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Wyszukujesz frazę "Ahmed, Ali" wg kryterium: Autor


Tytuł:
Consequences of Mercury Used by Artisanal and Small-Scale Gold Mining Processes a Case of River Nile State Sudan
Autorzy:
Ahmed, Ali M.A.
Purwanto, Purwanto
Sunoko, Henna Rya
Powiązania:
https://bibliotekanauki.pl/articles/124413.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
artisanal gold mining
small-scale gold mining
workers occupationally exposed
WOE
residents in surrounding communities
RSC
distribution of mercury concentration
surface soil
surface water
meteorological factors
topographical factors
Opis:
On the discovery of gold reserves in 14 states in Sudan, traditional gold mining suddenly started to flourish and hundreds of thousands of laymen became engaged in gold extraction. The new source of revenue generation added much to the empty treasury and the loss in petroleum revenue due to cessation of the south in 2011 could thus be compensated. Since gold extraction by artisanal and small-scale gold mining does not require much finance or advanced technology, it suited unskilled workers and many young people found their way into the new business. Although gold extraction generates high revenues, the use of mercury in gold extraction poses much threat to the environment and general health of miners and the surrounding areas. The research tries to investigate the effects of traditional gold mining in Alebedia area, Berber Locality in the River Nile State. The investigation includes A/ the effects of extraction methods on the environment and general health. B/ the level of education and its distribution within the miners and how it affected the awareness of the miners about the dangers of mining activities. C/ the period of stay that miners spend in the mining area its contribution on the awareness about the dangers and diseases inflicted on the miners, D/ the effects of traditional gold mining activities on natural environmental impacts and E/ the effects of the meteorological and topographical factors, the distribution and concentration of mercury in the area and their effects on the environment and general health. The research adopted the techniques of using random sampling and quantitative qualitative in addition to the analytical techniques. The research finally concluded that traditional gold mining has positive effects on the economic side and negative effects on the environment and general health.
Źródło:
Journal of Ecological Engineering; 2019, 20, 2; 106-115
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Social benefits of solar energy: Evidence from Bangladesh
Autorzy:
Salah Uddin, Gazi
Abdullah-Al-Baki, Chowdhury
Park, Donghyun
Ahmed, Ali
Tian, Shu
Powiązania:
https://bibliotekanauki.pl/articles/19905143.pdf
Data publikacji:
2023
Wydawca:
Instytut Badań Gospodarczych
Tematy:
energy transition
solar adaption
clean energy
education
welfare
Bangladesh
Opis:
Research background: The Bangladeshi government has set a plan to generate one-tenth of its electricity from solar and other renewable sources by 2030. Solar adoption surged in Bangladesh up until 2015, setting a global precedent for electrifying areas that were previously unconnected. The enhanced lighting offered by solar systems provides immediate benefits, including additional hours for household and business activities and extended study hours for school-going children. Purpose of the article: This study seeks to identify the determinants and welfare gains of solar adoption in rural areas by analysing three rounds of the Bangladesh Integrated Household Survey from 2011–12, 2015, and 2018–19. In addition to presenting new estimates of economic, environmental, and educational welfare gains, our research offers insights into how solar adoption relates to rural employment and the nutrition of children under five. Methods: We utilized both ordinary least squares and propensity score matching techniques to estimate the welfare effects of solar adoption. Only households that do not use electricity as their primary lighting source, such as those relying on solar or kerosene, are considered in our sample. Findings & value added: We have discovered that adopting solar is linked to higher income, increased expenditure, and growth in asset value. Additionally, there is a significant reduction in kerosene expenditure among adopters compared to non-adopters. Other observations reveal that households with solar setups tend to transition from sharecropping to trading and poultry farming. Children in these households also benefit from solar adoption in terms of education and nutrition. This study illustrates how solar energy can effectively address various welfare concerns in areas where the government cannot supply electricity. Given that recent global events have rendered underdeveloped countries more vulnerable to providing consistent electricity to their entire populations, this research suggests solar energy as a resilient electrification solution during crises.
Źródło:
Oeconomia Copernicana; 2023, 14, 3; 861-897
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Artificial Neural Network for Estimation of Local Scour Depth Around Bridge Piers
Autorzy:
Shakir Ali Ali, Ahmed
Günal, Mustafa
Powiązania:
https://bibliotekanauki.pl/articles/2097766.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
artificial neural network
bridge pier
hydraulics
local scour
Opis:
Local scour around bridge piers impairs the stability of bridges’ structures. Therefore, a delicate estimation of the local scour depth is vital in designing the bridge piers foundations. In this research, MATLAB software was used to train artificial neural network (ANN) models with four hundred laboratory datasets from different laboratory studies, including five parameters: pier diameter, flow depth flow velocity, critical sediment velocity, sediment particle size, and equilibrium local scour depth. The outcomes present that the ANN model with the Levenberg-Marquardt algorithm and 11 nodes in the single hidden layer gives an accurate estimation better than other ANN models trained with different training algorithms based on the regression results and mean squared error values. Besides, the ANN model accurately provides predicted local scour depth and is better than linear and nonlinear regression models. Furthermore, sensitivity analysis shows that removing pier diameter from training parameters diminishes the reliability of prediction.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2021, 68, 2; 87--101
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Designing an upper stage steering system for a formula FSAE car
Autorzy:
Wheatley, Greg
Ali, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/2091236.pdf
Data publikacji:
2021
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
design
steering
race car
projekt
układ kierowniczy
samochód wyścigowy
Opis:
The objective of this work is to design an upper stage steering system for the Formula FSAE car “Omega” that will effectively translate driver input force to the rack and pinion. The system consists of a steering wheel, steering shafts, universal joints, a quick release mechanism, and connection points to the car. Critical loads have been determined, and the final design has been validated using finite element analysis to ensure the safety of the assembly during normal operation and worst-scenario cases. The design key factors were performance, weight, cost, ergonomics, maintainability, manufacturability and reliability.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2021, 113; 205--218
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shifter mechanism design for FSAE motor sports vehicle JCU
Autorzy:
Wheatley, Greg
Ali, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/2091242.pdf
Data publikacji:
2021
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
mechanical shifter
solid linkage
spline attachments
FEA
mechaniczna skrzynia biegów
trwałe połączenie
mocowanie wielowypustowe
MES
Opis:
This report provides a design analysis of a replacement’s shifter mechanism for the 2014 model JCU Motorsports FSAE vehicle. Common FSAE shifter mechanisms were researched and reviewed to provide a better understanding of the needs required. A design approach was constructed to ultimately design a mechanism that conformed to all existing constraints and FSAE rules. Realistic load cases were identified and employed in the FEA analysis of the design. Supporting hand calculations were developed, proving the analysis to be accurate. Results showed the shifter mechanism does not fail under infinite life, with some parts of the design having a reasonably high safety factor, ensuring stability.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2021, 113; 219--229
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancing the flexural load capacity of the reinforced concrete simply supported slabs using damaged tires strips (DTS)
Autorzy:
Ali, Saba
Alalikhan, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/35556446.pdf
Data publikacji:
2022
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
flexural strength
reinforced concrete slabs
damaged tires strips
Opis:
Damaged tires or ended-life tires represent a difficult problem due to their ability to sustain for a long time which are not able to be dissolved easily. Present study focuses on the ability of using the damaged tires strips (DTS) in the field of structural engineering as an innovative reinforcing material used additionally with the main reinforcement. The adopted technique in the present work represents a clean solution to reuse and recycle DTS to increase the ultimate flexural capacity of the reinforced concrete one-way and two-way slabs used in structural systems satisfying clean environment and economic considerations. The tests were conducted upon eight specimens of reinforced concrete one-way slabs (RCOWS) and two specimens of reinforced concrete two-way slabs (RCTWS) reinforced by the DTS as an additional reinforcement. Experimentally obtained results exhibited enhancement for the ultimate flexural load capacity of the RCOWS and RCTWS models reinforced by the DTS in the range of 16–80 and 14.28% respectively, compared to the original reference specimens.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2022, 31, 2; 101-112
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved CSE with DLS-MMSE Criteria in TH-UWB System
Autorzy:
Djebbari, Ali
Elahmar, Sid Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/2058501.pdf
Data publikacji:
2022
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
channel shortening equalizer
inter-symbol interferences
rake receiver
time hopping
ultra-wide band
ZF-MMSE
Opis:
This article presents a study on the use of deter ministic least squares criteria combined with the minimum mean square error method for the purpose of computing filter coefficients of the channel shortening equalizer. This method is well known to alleviate inter-symbol interference in time hopping UWB systems. The validity of this method is applied to shorten the impulse response of the effective UWB channels and, therefore, reduce the complexity of the rake receiver. Results show a very promising advantage compared to partial rake (P-Rake), selective-rake (S-Rake) and optimal maximum shortening signal-to-noise ratio methods.
Źródło:
Journal of Telecommunications and Information Technology; 2022, 1; 93--98
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluating the connectivity level of Fayoum city roads network: a new method using GIS
Ocena poziomu spójności sieci dróg miejskich Fayoum: nowa metoda wykorzystująca GIS
Autorzy:
Saleh, Ahmed Younes
Abdu, Saeed Ahmed
Ali, Hanaa Nazer
Powiązania:
https://bibliotekanauki.pl/articles/2089773.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Gdański. Komisja Geografii Komunikacji Polskiego Towarzystwa Geograficznego
Tematy:
connectivity level
GIS
map algebra
network analysis
urban road network
poziom spójności
algebra mapy
analiza sieci
sieć dróg miejskich
Opis:
Road networks within cities are a vital component of the socio-economic development processes. Many countries have sought to examine and evaluate the efficiency of road networks within urban areas because of the increasing demand for transportation. Thus, networks should be evaluated to guide the development of transport systems and infrastructure within cities. This study evaluates the connectivity level of the road network parts in Fayoum city, Egypt, through the application of some indicators of connectivity measurement, such as Beta, Alpha, Gamma, Connectivity degree, and the density of edges and nodes. The study follows a new method for evaluation; it does not apply the indicators on the network as a whole; however, it divides the city into zones and calculates the indicators of each zone using the Arc GIS 10.2.1 program. The authors applied the map Algebra method to map the results of the six indicators in one index called the Total Connectivity Index (TCI). The TCI gives more consistent results than other indices, and it is more related to different spatial patterns of roads. According to this indicator, most of the city road network seem to have a good connectivity level, whereas the city marginal areas prove to have a poor connectivity level. Therefore, any efforts to develop or construct new roads should be in the marginal areas of the city.
Źródło:
Prace Komisji Geografii Komunikacji PTG; 2018, 21(4); 60-72
1426-5915
2543-859X
Pojawia się w:
Prace Komisji Geografii Komunikacji PTG
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Desulfurization of Crude Oil by Laboratory Developed Multipumping Flow Injection Analysis System with Optimization by Response Surface Methodology
Autorzy:
Hadi, Ahmed Abdulrazzaq
Ali, Ali Abdulkhabeer
Khathi, Mohammed Turki
Powiązania:
https://bibliotekanauki.pl/articles/2202370.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
multi-pumping flow system
desulfurisation
response surface
optimal conditions
Opis:
Sour crude oil is the crude oil that contains a high level of sulfur impurity. It can be toxic and corrosive. Before this lower-quality crude can be processed into other crude oil derivatives, the sulfur content must be reduced, raising the processing cost. A homemade semi-automated multipumping flow analysis system was constructed, consisting of several parts available on the local markets and at low economic costs to decrease the sulfur content of crude oil samples collected. The central composite design (CCD) and response surface methodology (RSM) have been used for modeling and optimization. The effects of the operational parameters, including polar and nonpolar solvent types, solvent flow rates (10–40 ml/min), mixing coil lengths (120–200 min), temperature (30–60 °C), and solvent entry time to the system (0–60 sec) were studied. Experimental and theoretical applications were made to determine the optimal sulfur content, which came out to be 1.438 and 1.395 wt.%, respectively. This system evaluated the effectiveness of the sulfur removal content for actual heavy crude oil by experimentally and theoretically to be 65.73 and 66.75% respectively. The semi-automated system was applied successfully to reduce the sulfur content in a highly sensitive and accurate way.
Źródło:
Journal of Ecological Engineering; 2023, 24, 2; 328--339
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel approach for big data classification based on hybrid parallel dimensionality reduction using spark cluster
Autorzy:
Ali, Ahmed Hussein
Abdullah, Mahmood Zaki
Powiązania:
https://bibliotekanauki.pl/articles/305766.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
big data
dimensionality reduction
parallel processing
Spark
PCA
LDA
Opis:
The big data concept has elicited studies on how to accurately and efficiently extract valuable information from such huge dataset. The major problem during big data mining is data dimensionality due to a large number of dimensions in such datasets. This major consequence of high data dimensionality is that it affects the accuracy of machine learning (ML) classifiers; it also results in time wastage due to the presence of several redundant features in the dataset. This problem can be possibly solved using a fast feature reduction method. Hence, this study presents a fast HP-PL which is a new hybrid parallel feature reduction framework that utilizes spark to facilitate feature reduction on shared/distributed-memory clusters. The evaluation of the proposed HP-PL on KDD99 dataset showed the algorithm to be significantly faster than the conventional feature reduction techniques. The proposed technique required >1 minute to select 4 dataset features from over 79 features and 3,000,000 samples on a 3-node cluster (total of 21 cores). For the comparative algorithm, more than 2 hours was required to achieve the same feat. In the proposed system, Hadoop’s distributed file system (HDFS) was used to achieve distributed storage while Apache Spark was used as the computing engine. The model development was based on a parallel model with full consideration of the high performance and throughput of distributed computing. Conclusively, the proposed HP-PL method can achieve good accuracy with less memory and time compared to the conventional methods of feature reduction. This tool can be publicly accessed at https://github.com/ahmed/Fast-HP-PL.
Źródło:
Computer Science; 2019, 20 (4); 411-429
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differential designing for FSAE motor sports vehicle JCU
Autorzy:
Marciano, Pieta
Wheatley, Greg
Ali, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/2173482.pdf
Data publikacji:
2022
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
torque transition
shaft system
FEA
przejście momentu obrotowego
układ wałów
Opis:
The objective of this work was to design a differential assembly for an FSAE motor sports vehicle. The designed differential system consists of 3 braces made of AISI 1045 steel. The output shafts were made of AISI 4140 steel with hardened splines. These shafts were initially going to drive 94 mm constant velocity shafts. A 75 mm tripod joint was used to minimize the weight and cost of the system. The housing was held together with grade 12.8 hex head bolts, and the shafts were bolted onto the tri-pod joints using bolts of grade 8.8 which complies with FSAE rules. The input shaft which acts on the differential itself is made of EN36A steel and is where the drive sprocket is bolted to. All components were modeled using Finite Element Analysis to determine stresses and displacements under operating conditions.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2022, 114; 67--78
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rola ultrasonografii w rozpoznawaniu utajonych złamań kości łódeczkowatej
The role of ultrasonography in the diagnosis of occult scaphoid fractures
Autorzy:
Ali, Mohammed
Ali, Mujtaba
Mohamed, Ahmed
Mannan, Syed
Fallahi, Farshid
Powiązania:
https://bibliotekanauki.pl/articles/1032202.pdf
Data publikacji:
2018
Wydawca:
Medical Communications
Tematy:
złamanie kości łódeczkowatej
Opis:
Background: Ultrasonography is widely utilized by emergency physicians and radiologists to diagnose various orthopaedic diseases, including fractures. We aim to derive a definitive estimate of the diagnostic accuracy of ultrasonography in clinically suspected scaphoid fractures. Methods: We undertook a systematic review and meta-analysis of included diagnostic cohort studies that discussed the use of ultrasonography in the diagnosis of occult scaphoid fractures. We searched the National Institute for Health and Care Excellence database using the Healthcare Databases Advanced Search tool. In addition, we utilized the PubMed database to search the Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Cumulative Index of Nursing and Allied Health and Allied and Complimentary Medicine databases. Studies were included if they discuss the role of ultrasound imaging in the diagnosis of scaphoid fractures based on cortical interruption, radio-carpal effusion and scapho-trapezium-trapezoid effusion. Quality assessment was performed using the methodological index for non-randomized studies scoring system. Results: 6 non-randomized control studies met the inclusion criteria. Collectively, these included 236 patients with a mean age ranging from 18 to 41.2 years. The quality of these articles ranged between moderate and high based on the methodological index for nonrandomized studies score. The mean sensitivity was 88.95% (standard deviation 10.03) and mean specificity was 89.50% (standard deviation 12.21). Conclusion: The current literature reveals high sensitivity and specificity in the use of ultrasonography in scaphoid fracture diagnosis. However, multiple factors including technical differences in ultrasound machines and probes, small sample sizes and variability of subsequent confirmatory tests have created a challenge in determining the ultimate reliability of ultrasonography in the diagnosis of occult scaphoid fractures. Considering these factors and limitations, large-sample and high-quality clinical trials are needed to adequately assess its reliability for this purpose. One stop clinics, in the authors’ opinion, would be an ideal setting for its introduction as well as for future trials.
Wprowadzenie: Ultrasonografia jest szeroko wykorzystywana w medycynie ratunkowej i radiologii do diagnozowania różnych schorzeń narządu ruchu, w tym złamań. Celem pracy jest jednoznaczne ustalenie stopnia dokładności badania ultrasonograficznego w przypadku klinicznego podejrzenia złamania kości łódeczkowatej. Metody: W pracy podjęto się przeglądu systematycznego i metaanalizy wybranych badań kohortowych, które dotyczą wykorzystania ultrasonografii w rozpoznawaniu utajonych złamań kości łódeczkowatej. Przeszukano bazę National Institute for Health and Care Excellence z wykorzystaniem narzędzia wyszukiwania Healthcare Databases Advanced Search. Wykorzystano również bazę PubMed do przeszukania baz danych Medical Literature Analysis and Retrieval System Online, Excerpta Medica, Cumulative Index of Nursing and Allied Health oraz Allied and Complimentary Medicine Database. Do analizy włączano te badania, które dotyczą roli badania ultrasonograficznego w rozpoznawaniu złamań kości łódeczkowatej na podstawie przerwania ciągłości istoty zbitej, wysięku w stawie promieniowo-nadgarstkowym oraz wysięku w stawie łódeczkowato-czworobocznym. Oceny jakości analizowanych prac dokonywano na bazie klasyfikacji punktowej badań nierandomizowanych. Wyniki: Kryteria włączenia spełniło 6 badań porównawczych bez randomizacji. Badania te obejmowały łącznie 236 pacjentów o średniej wieku od 18 lat do 41,2 roku. Jakość artykułów wahała się pomiędzy średnią a wysoką na podstawie wyniku w klasyfikacji punktowej badań nierandomizowanych. Średnia czułość badania w analizowanych pracach wynosiła 88,95% (odchylenie standardowe: 10,03), a średnia swoistość 89,50% (odchylenie standardowe: 12,21). Wnioski: Najnowsze doniesienia literaturowe mówią o wysokiej czułości i swoistości badania ultrasonograficznego w rozpoznawaniu złamania kości łódeczkowatej. Ustalenie wiarygodności badania ultrasonograficznego w rozpoznawaniu utajonych złamań kości łódeczkowatej jest jednak trudne ze względu na liczne czynniki, takie jak różnice techniczne pomiędzy stosowanymi aparatami i głowicami ultrasonograficznymi, niska liczebność badanych prób oraz różnice w typie badania stosowanego do potwierdzenia rozpoznania. Ze względu na te czynniki i ograniczenia do właściwej oceny wiarygodności badania ultrasonograficznego stosowanego do omawianego celu potrzebne są badania kliniczne wysokiej jakości. Według autorów ośrodki kompleksowej diagnostyki typu „one stop clinic” byłyby idealnym miejscem na wprowadzenie badań ultrasonograficznych do diagnostyki złamań kości łódeczkowatej oraz na prowadzenie badań klinicznych w przyszłości.
Źródło:
Journal of Ultrasonography; 2018, 18, 75; 325-331
2451-070X
Pojawia się w:
Journal of Ultrasonography
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural analysis of functionally graded material using sigmioadal and power law
Autorzy:
Abd-Ali, Nabel Kadum
Madeh, Ahmed Raee
Powiązania:
https://bibliotekanauki.pl/articles/1955209.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
FGM shell
sigmoidal law
power law
Hamilton’s principle
stress analysis
prawo sigmoidalne
zasada Hamiltona
analiza naprężeń
Opis:
The stress-strain relations, displacement distribution, stress resultants and mid plane strain resultants of a functionally graded material plate are studied using Hamilton’s principle. A simply supported rectangular thick shell direct stress, inplane shear stress, transverse stress and displacement are investigated. The analysis and modeling of five layers FGM shell is carried out using MATLAB19 code with ABAQUS20 software. Using distinct materials on the top and bottom layers of the shell, a transverse uniform load in five degrees - of - freedom is applied with a specific Poisson's ratio and Young's modulus in a power and sigmoidal law function through the thickness direction. A power law was used to determine the distribution of properties through shell thickness. The results showed that the bottom layer affected significantly most stress due to subjected to the most in-plane stress while the displacement is greatest at the top layer.
Źródło:
Diagnostyka; 2021, 22, 4; 59-65
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The stress analysis effect on structural health monitoring in functionally graded shell
Autorzy:
Madeh, Ahmed Raee
Abd-Ali, Nabel Kadum
Powiązania:
https://bibliotekanauki.pl/articles/2096204.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
health monitoring
FG shell
power law
sigmoidal law
virtual energy method
thickness ratio
monitorowanie konstrukcji
prawo energetyczne
prawo sigmoidalne
Opis:
The common damage in engineering structures, especially in functionally graded materials, such as failure resulting from fiber breaking or cracking in the matrix or deboning between fibers and matrix, as well as the delamination between the composite material plies and between its layers, may be due to thermal effects, vibration, load concentration as a result of stress and strain for provides information’s about structural health monitoring. Virtual energy method such as Hamilton's was used to investigate the effect of the design parameters such as side to thickness and modular as well as material graduation index ratio on the stress-strain relationships, displacement, resultants of stresses, and resultants of mid plane strain. The analysis and simulation of the FGM shells is done in this paper utilizing MATLAB19 code and ABAQUS20 programs. The distribution of characteristics across shell thickness had also been determined using a power law. Normal stress was varied gradually from 5.74 MPa to 9.55 MPa with material index (n) from 0 to 10 respectively, while shear stress varied from 4.2 to 8.23 MPa for the same value of (n). The strain percent increased slightly from 0.00059 to 0.0012 with displacement 0.22 and 1.2 respectively for the same value of (n).
Źródło:
Diagnostyka; 2022, 23, 3; art. no. 2022302
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Health monitoring of composite car roof failure under effect of different impact velocity
Autorzy:
Madeh, Ahmed Raee
Abd-Ali, Nabel Kadum
Powiązania:
https://bibliotekanauki.pl/articles/27313827.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
failure index
Tsai-Wu
health monitoring
car roof
stress analysis
wskaźnik uszkodzeń
dach samochodu
analiza naprężeń
uderzenie
Opis:
During this work, the roof of the car was used as an engineering application to study and monitor the occurrence of failures under the influence of various loads. The shells are made of multilayer composite materials using epoxy resin reinforced with carbon fiber and aluminium oxide granules as reinforcing materials to increase the impact resistance that vehicles may be exposed to while driving, in addition to other loads and conditions such as vibration and constant exposure to moisture and sunlight. The simulation program was used the finite elements method through software Abaqus program in addition to the program MATLAB v.2020a to process the data obtained from the method that used in this study. The results showed that the specified failure criteria work well for predicting the overall structural response such as strain, stress, maximum force and displacement. The losses of energy of impact collision increase as an increase in impact velocity. The dissipation of energy which depend on the stress and strain distribution during elastic deformations. The effect of thickness of the lamina plays an important role in health monitoring the structure.
Źródło:
Diagnostyka; 2023, 24, 4; art. no. 2023406
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Internet of things in Smart Environment: Concept, Applications, Challenges, and Future Directions
Autorzy:
Elmustafa, Sayed Ali Ahmed
Mujtaba, Elbagir Yousef
Powiązania:
https://bibliotekanauki.pl/articles/1059415.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Agriculture Control
Air Pollution
Chemical Leakage
IoT
Monitoring Systems
Radiation Monitoring
Smart Environment
Waste Management
Water Quality
Weather Monitoring
Opis:
Environmental phenomena have a major impact on our daily lives. These include changes affecting the sources of life such as in the waters and air of our world, which have been degraded in purity. The term ‘smart environment’ is defined as a technology that provides many facilities and solutions for many environmental application issues related to water quality and health, air pollution, weather, radiation monitoring, waste management, natural disaster, and many other environment indicators. Smart environment sensors integrated with ‘Internet of Things’ (IoT) technology can provide a new concept in tracking, sensing and monitoring objects of environment. This can provide potential benefits leading up to the possibility of achieving a green world and a sustainable lifestyle. IoT allows environmental sensors to connect with other systems such smart phones through Bluetooth or Wi-Fi to send enormous amounts of data to the network and can allow us to have a better understanding of our surroundings and find suitable solutions for today environmental problems. In this review article, we will provide a brief conception of environment areas of study based on IoT technology and discuss the justification behind using IoT in the field of environmental studies. Moreover, we will investigate many proposed applications of environmental research based upon IoT.
Źródło:
World Scientific News; 2019, 134, 1; 1-51
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanotechnology in Communication Engineering: Issues, Applications, and Future Possibilities
Autorzy:
Elmustafa, S. Ali Ahmed
Sohal, Harwinder Singh
Powiązania:
https://bibliotekanauki.pl/articles/1182754.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Molecular Nano Technology (MNT)
Molecular communication
Nano machines
Nano-communications
Nanotechnology
Opis:
Nanotechnology nowadays became the most amazing studies developed and an active research areas in many fields including civil, chemical engineering, electronics, and medicine, also in materials. In modern sciences, nanotechnology is considered as the next industrial revolution which it may give more possibilities exceed our expectations in many fields. In telecommunication engineering nanotechnology could provide effective solutions for power efficient computing, sensing, memory enlargement, and human machine interaction. Nanotechnology in communication systems also provides ability for manufacturers to produce computer chips and sensors that are considerably smaller, faster, more energy efficient, and cheaper to manufacture than their present-day modules. In this paper an overview of many issues related to nanotechnology in communication systems are discussed, and also paper will provides a brief ideas of the potential application of various nanotechnology developments in the communication systems and the potential for future possibilities researches that may lead to improved communication systems.
Źródło:
World Scientific News; 2017, 66; 134-148
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Analysis of Atmospheric Water Harvester Using Ammonia Vapour Absorption System
Autorzy:
Qandil, Ahmed
Othman, Ali
Beithou, Nabil Ibrahim
Powiązania:
https://bibliotekanauki.pl/articles/2202359.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
atmospheric water harvester
vapour absorption system
velocity effect
AWH analysis
AWG application
Opis:
There are increasing concerns for the promising future of atmospheric water harvesters (AWH). AWH have been analysed theoretically and experimentally using different technologies such as Vapour Compression (VC) Thermoelectric (TE), Sorption (absorption, adsorption) and shape-based techniques. These techniques are suffering from low water harvesting or high energy consumption. The ammonia vapour absorption system (VAS) (which can be operated using renewable energy sources) has not yet been analysed experimentally. In this study, the AWH based on ammonia VAS has been studied experimentally, the effect of air flow velocity and ambient conditions have been analysed. The comparison between the existing techniques and VAS was performed to explore the possibility of implementing biomass, geothermal and solar energy in generating water from atmosphere, thus reducing the cost of the m3 of water produced.
Źródło:
Journal of Ecological Engineering; 2023, 24, 2; 221--229
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Food Loss Factors in the Cold Supply Chain: a Case Study in the Poultry Sector
Autorzy:
Ayadi, Imen
Elleuch, Mohamed Ali
Frikha, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/33914803.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Ekonomiczny w Katowicach
Tematy:
cold chain (CC)
food loss factors (FLF)
MCDM
poultry supply chain
sensitivity analysis
Opis:
Food loss is one of the challenges in the cold chain (CC), which can lead to serious problems with human safety, environment, and economies around the world. Recently, reducing food loss has drawn public attention; previous studies mostly gave attention to food loss drivers in the retailer-consumer stages of the supply chain. In this study, we focused on identifying food-loss-factors (FLF) all over the CC, and developed an approach based on multi decision-making methods and fuzzy sets to rank FLFs by those who have more influence on food loss in the poultry sector. The first phase concerns the identification of FLFs based on the literature as well as experts opinions in the poultry field. Then fuzzy Delphi method was implemented to reach the consistency level of >75% among all the group members. In the second phase, fuzzy AHP method was employed for the weighting of FLFs, in order to rank them. For the validation of our contribution, a sensitivity analysis was performed. This research presents a guide for decision makers in the CC to help them make an efficient strategy plan to reduce food loss during logistic activities.
Źródło:
Multiple Criteria Decision Making; 2023, 18; 5-28
2084-1531
Pojawia się w:
Multiple Criteria Decision Making
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Leczenie choroby zwyrodnieniowej stawu biodrowego przy zastosowaniu iniekcji osocza bogatopłytkowego pod kontrolą ultrasonograficzną: systematyczny przegląd piśmiennictwa
The use of ultrasound-guided platelet-rich plasma injections in the treatment of hip osteoarthritis: a systematic review of the literature
Autorzy:
Ali, Mohammed
Mohamed, Ahmed
Elamin Ahmed, Hussam
Malviya, Ajay
Atchia, Ismael
Powiązania:
https://bibliotekanauki.pl/articles/1032150.pdf
Data publikacji:
2018
Wydawca:
Medical Communications
Tematy:
osocze bogatopłytkowe
Opis:
Purpose: This review aims to determine whether ultrasound-guided platelet-rich plasma injection has any role in improving clinical outcomes in patients with hip osteoarthritis. Methods: A search of the National Institute for Health and Care Excellence database using the Healthcare Databases Advanced Search tool was conducted. The PubMed database was also utilised to search the Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Cumulative Index of Nursing and Allied Health and Allied and Complimentary Medicine databases. The Preferred Reporting Items for Systematic Review and Meta-Analysis methodology guidance was employed and a quality assessment was performed using the Jadad score. Results: Three randomised clinical trials met the inclusion criteria and were included for analysis. All three trials were of good quality based on the Jadad score. A total of 115 patients out of 254 received platelet-rich plasma injections under ultrasound guidance. The platelet-rich plasma recipient group included 61 males and 54 females with an age range from 53 to 71 years. Outcome scores show an improvement of symptoms and function maintained up to 12 months following platelet-rich plasma injection. Conclusions: Literature to date concludes that intra-articular platelet-rich plasma injections of the hip, performed under ultrasound guidance to treat hip osteoarthritis, are well tolerated and potentially efficacious in delivering long-term and clinically significant pain reduction and functional improvement in patients with hip osteoarthritis. Larger future trials including a placebo group are required to further evaluate these promising results. Level of evidence: Level I, a systematic review of level I studies.
Cel: Celem przeglądu jest ustalenie, czy iniekcja osocza bogatopłytkowego pod kontrolą ultrasonograficzną przyczynia się do poprawy wyników klinicznych u pacjentów z chorobą zwyrodnieniową stawu biodrowego. Metody: Przeszukano bazę danych National Institute for Health and Care Excellence przy użyciu narzędzia Healthcare Databases Advanced Search. Wykorzystując bazę danych PubMed, przeszukano również: Medical Literature Analysis and Retrieval System Online, Excerpta Medica, Cumulative Index of Nursing and Allied Health Literature oraz Allied and Complementary Medicine Database. Zastosowano metodologię zgodną z deklaracją Preferred Reporting Items for Systematic Review and Meta-Analysis, a ocenę jakości badań przeprowadzono przy wykorzystaniu skali Jadada. Wyniki: Trzy randomizowane badania kliniczne spełniły kryteria włączenia do przeglądu i zostały uwzględnione w analizie. Na podstawie wyników w skali Jadada stwierdzono, że wszystkie trzy badania odznaczały się wysoką jakością. Łącznie 115 spośród 254 uczestniczących w badaniach pacjentów otrzymało iniekcje z osocza bogatopłytkowego pod kontrolą ultrasonograficzną. Grupa osób leczonych osoczem bogatopłytkowym liczyła 61 mężczyzn i 54 kobiety w przedziale wiekowym od 53 do 71 lat. Wyniki oceny wskazują na zmniejszenie nasilenia objawów i poprawę stanu czynnościowego stawu, które utrzymywały się do 12 miesięcy od iniekcji osocza bogatopłytkowego. Wnioski: Jak wskazuje dostępne piśmiennictwo, iniekcje osocza bogatopłytkowego podawane dostawowo pod kontrolą ultrasonograficzną w leczeniu choroby zwyrodnieniowej stawu biodrowego są dobrze tolerowane i potencjalnie skuteczne pod względem długotrwałego i istotnego klinicznie ograniczania dolegliwości bólowych i poprawy stanu czynnościowego stawu. W celu bardziej szczegółowej oceny tych obiecujących wyników niezbędne są zakrojone na większą skalę badania z uwzględnieniem grupy placebo. Poziom dowodów: Poziom I, systematyczny przegląd badań poziomu I.
Źródło:
Journal of Ultrasonography; 2018, 18, 75; 332-337
2451-070X
Pojawia się w:
Journal of Ultrasonography
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of tractor wheels on physical properties of different soil types and the irrigation efficiency of the furrow irrigation method
Autorzy:
Vistro, Rahim Bux
Talpur, Mashooque Ali
Shaikh, Irfan Ahmed
Mangrio, Munir Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/2073733.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
furrow storage efficiency
ridge storage efficiency
irrigation methods
soil physical properties
tractor wheel trafficking
water use efficiency
Opis:
In furrow irrigation, the maximum lateral movement of water in ridges is more desirable than the vertical downward movement. This can be achieved by compacting the furrows. Thus, the study examines the impact on furrow soil compaction by tractor wheel trafficking during mechanical operations in the different soil types. In this experiment, the three-wheel tractor compaction includes: 1) control (no soil compaction), 2) compaction through 3-wheel tractor passes, and 3) compaction through 6-wheel passes under three different soil textural classes such as: clay loam, silty clay loam and silty loam soils. The impact of various treatments on clay loam, silty clay loam, and silty loam under 3- and 6-wheel passes showed increased bulk density (7–12%), field capacity (9–19%), ridge storage efficiency (35–38%), water use efficiency (16–20.5%) and decreased soil porosity (7–16%), infiltration (8–20%), and furrow storage efficiency (28–41%) over the control. This study shows comparable results of 6-passes with other studies in which more than 6-passes were used to compact the soil. This study suggested that farmers can maximise water use efficiency by compacting their furrows using 6-passes tractor trafficking.
Źródło:
Journal of Water and Land Development; 2022, 52; 166--171
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Apolocystis proventus sp. nov. (Apicomplexa: Monocystinae) a New Species of Aseptate Gregarine from Egyptian Earthworms: Pheretima californica and Pheretima elongata (Annelida: Oligochaeta)
Autorzy:
RAMADAN, Nadia
FAWZ, Samia
ALI, Medhat
NIGM, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/763776.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Gregarine, Pheretima, Coelom, Apolocystis, Pharyngeal glands, Apicomplexa and Monocystinae
Opis:
A new acephaline gregarine is described from the earthworms Pheretima californica and Pheretima elongata. The gregarine was either embedded in the pharyngeal glandular tissue or found free in the coelomic fluid around the pharyngeal region in front of the crop. Adult trophozoites measured 48–65 µm in diameter and are mostly active with a wavy pellicle. Heterogeneity in the endoplasm of active trophozoites was observed. Gametocysts measured 56–81 µm in diameter, with a characteristic thick cyst wall. Navicular sporocysts measured 5.8 ± 0.2 × 3.5 ± 0.4 µm, with small truncate plugs.
Źródło:
Acta Protozoologica; 2015, 54, 3
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Internet of Things Applications, Challenges and Related Future Technologies
Autorzy:
Zeinab, Kamal Aldein Mohammed
Elmustafa, Sayed Ali Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/1178659.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Future Technologies
IoT Applications
Smart Cities
Smart Energy and Grid
Smart Environment
Smart Healthcare
Smart Manufacturing
Opis:
Nowadays Internet of Things (IoT) gained a great attention form researchers, since it becomes an important technology that promises a smart human being life, by allowing a communications between objects, machines and every things together with peoples. IoT represents a system which consists a things in the real world, and sensors attached to or combined to these things, connected to the Internet via wired and wireless network structure. The IoT sensors can use various types of connections such as RFID, Wi-Fi, Bluetooth, and ZigBee, in addition to allowing wide area connectivity using many technologies such as GSM, GPRS, 3G, and LTE. IoT-enabled things will share information about the condition of things and the surrounding environment with people, software systems and other machines. by the technology of the IoT , the world will becomes smart in every aspects , since the IoT will provides a means of smart cities , smart healthcare , smart homes and building , in addition to many important applications such as smart energy , grid , transportation , waste management and monitoring . In this paper we review a concept of many IoT applications and future possibilities for new
Źródło:
World Scientific News; 2017, 67, 2; 126-148
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Face Recognition Comparative Analysis Using Different Machine Learning Approaches
Autorzy:
Ahmed, Nisar
Khan, Farhan Ajmal
Ullah, Zain
Ahmed, Hasnain
Shahzad, Taimur
Ali, Nableela
Powiązania:
https://bibliotekanauki.pl/articles/2024199.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
linear discriminant analysis
k-nearest neighbor
support vector machine
principal component analysis
liniowa analiza dyskryminacyjna
maszyna wektorów podporowych
analiza głównych składowych
Opis:
The problem of a facial biometrics system was discussed in this research, in which different classifiers were used within the framework of face recognition. Different similarity measures exist to solve the performance of facial recognition problems. Here, four machine learning approaches were considered, namely, K-nearest neighbor (KNN), Linear Discriminant Analysis (LDA), Support Vector Machine (SVM), and Principal Component Analysis (PCA). The usefulness of multiple classification systems was also seen and evaluated in terms of their ability to correctly classify a face. A combination of multiple algorithms such as PCA+1NN, LDA+1NN, PCA+ LDA+1NN, SVM, and SVM+PCA was used. All of them performed with exceptional values of above 90% but PCA+LDA+1N scored the highest average accuracy, i.e. 98%.
Źródło:
Advances in Science and Technology. Research Journal; 2021, 15, 1; 265-272
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power System Transient Stability Case Study: A Power Sub-Station Plant in Sudan
Autorzy:
Abbas, Asma
Kamal, Ramadan Doud
Elmustafa, Sayed Ali Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/1193487.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Dynamic Stability
GARRI power stations
Swing Equation
Transient Stability
power angle
synchronism
Opis:
Power system stability is defined by the tendency of the energy system to develop recovery forces equal or greater than the disturbing forces to maintain a stable equilibrium state. In general, power system stability problems are usually divided into two parts, steady state and transient state. An extension of steady-state stability is dynamic stability. Transient stability deals with the effects of large disturbances such as malfunctions, sudden line interruptions, and sudden application or load removal. This research is presents load angle method to transient stability problem for multi-machine system. The ETAP program is used to simulate the above method to study transient stability. A sub-station plant in Khartoum (GARRI) with four generation sections (1, 2 and 4) has been taken as a case study. The simulation result shows that when a single line-ground fault occurs at main busbar and cleared at time t = 0.4 sec the system is stable, in case 2, when the same fault cleared at t = 3 sec the system become unstable.
Źródło:
World Scientific News; 2021, 158; 267-284
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of heat transfer on peristaltic flow in presence of heat generation against higher value of Reynolds number using FEM
Autorzy:
Javed, Tariq
Hamid, Abdul H.
Ahmed, Bilal
Ali, Nasir
Powiązania:
https://bibliotekanauki.pl/articles/1839717.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
finite element method
peristaltic flow
heat transfer
Opis:
In the present investigation, heat transfer analysis of peristaltic flow in the presence of heat generation against high values of the Reynolds number using a numerical technique is presented. The Finite Element Method with the assistance of Galerkin’s variational method has been used on the governing Navier-Stokes equation in the stream-vorticity form. The graphs of computed longitudinal velocity, temperature distribution and pressure rise per wavelength are plotted against different values of an emerging parameter using a stream function and vorticity. The presented results are valid beyond the restrictions of long wavelength and low Reynolds number limits. Moreover, large values of the Reynolds number increases pressure rise per wavelength.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 2; 279-292
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical vapour compression refrigeration system: review part 1: environment challenge
Autorzy:
Mahmood, Raid Ahmed
Ali, Omar M.
Noor, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/1839710.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
czynnik chłodniczy
układ chłodniczy
warstwa ozonowa
alternative refrigerant
mixture refrigerants
vapour compression refrigeration system
ozone depletion potential
global worming potential
R507A refrigerant
natural refrigerant
R-718 (water/steam)
Opis:
In Australia and others developed countries, concerns about global warming have increased, and these concerns influence the use of refrigerants as working fluids in mechanical vapour compression refrigeration systems. One of the most important aspects of refrigerant selection is to reduce its impact on the environment and the ozone layer. This paper provides a comprehensive review of various theoretical and experimental studies which have been carried out on air conditioning and refrigeration applications to investigate the effect of refrigerants on the environment. The analysis in this paper reveals that alternative refrigerants are the most suitable working fluids that can be used in refrigeration systems to meet the needs of the environment. This study also suggests that natural types of refrigerants such as water, carbon dioxide, and hydrocarbon will play a significant role in protecting the environment and providing alternative friendly refrigerants to be used in refrigeration and air conditioning systems.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 4; 130-147
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Modified Rice Husks for Removal of Aniline in Batch Adsorption Process: Optimization and Isotherm Study
Autorzy:
Dakhil, Ihsan Habib
Naser, Ghazi Faisal
Ali, Ahmed Hassan
Powiązania:
https://bibliotekanauki.pl/articles/1955426.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
adsorption
aniline
modified rice husk
optimization
Opis:
The present work is aimed at investigating the capability of chemically modified rice husks (MRH) for the reduction of aniline ions from industrial wastewater. The experiments have been conducted to examine the influence of four operating parameters in the batch adsorption technique. The effect of initial concentrations of aniline (10–100) mg•L-1, MRH dose (0.1–1) g/100 ml, pH (3–9), and contact time (10–90) min has been studied. The selected range of operating factors was designed using the response surface method to establish a mathematical model that describes the adsorption process. The optimum parameters were 25 mg•L-1 initial concentration of aniline, 0.68 g MRH dose, 6.6 pH, and 70 min contact time. The point of zero charge was found equal to 6.8. The maximum removal efficiency of 84.97% was found under optimum conditions. The consistency of the mathematical model has been examined and the equilibrium results confirmed with the standard adsorption isotherm models, Langmuir and Freundlich, with a high correlation coefficient.
Źródło:
Journal of Ecological Engineering; 2021, 22, 7; 179-189
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In-situ performance evaluation of photovoltaic solar water pumping system in the rural region
Autorzy:
Maka, Ali Omar
Chaudhary, Tariq Nawaz
Hasan, Abdulazez
Gatou, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/95219.pdf
Data publikacji:
2019
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
water pumping
performance analysis
rural region
photovoltaic solar
pompownia wody
analiza wydajności
region wiejski
energia słoneczna fotowoltaiczna
Opis:
The Photovoltaic solar cells convert the radiant energy from the Sun directly to electricity. Solar photovoltaic systems can help to fulfil the entire energy demands in rural areas by harnessing all the opportunities and potentials. The water is an important element in the life of plants, animals and human being. In this paper, it has been studied that solar energy could be used for water pumping applications such as providing water to rural and remote areas. It is being practiced in south Libya. The data is being collected over two years by measuring the water flow on daily basis at pumping head of (35m). In addition, this presents an evaluation of PV system in water pumping and piping systems and estimation of pumping energy cost. The solar pumping systems depend on water flow rate, pumping head and solar irradiance. The system components contain inverter, pump and PV generator. Besides, the effects of the climate and operating conditions on the performance of PV pumping systems has been discussed.
Źródło:
Journal of Mechanical and Energy Engineering; 2019, 3, 1; 69-76
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beam Pattern Optimization Via Unequal Ascending Clusters
Autorzy:
Abdulqader, Ahmed Jameel
Mohammed, Jafar Ramadhan
Ali, Yessar E. Mohammad
Powiązania:
https://bibliotekanauki.pl/articles/2200966.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
beam pattern
clustered array
genetic algorithm
sidelobes
Opis:
In this paper, two different architectures based on completely and sectionally clustered arrays are proposed to improve the array patterns. In the wholly clustered arrays, all elements of the ordinary array are divided into multiple unequal ascending clusters. In the sectionally clustered arrays, two types of architectures are proposed by dividing a part of the array into clusters based on the position of specific elements. In the first architecture of sectionally clustered arrays, only those elements that are located on the sides of the array are grouped into unequal ascending clusters, and other elements located in the center are left as individual and unoptimized items (i.e. uniform excitation). In the second architecture, only some of the elements close the center are grouped into unequal ascending clusters, and the side elements were left individually and without optimization. The research proves that the sectionally clustered architecture has many advantages compared to the completely clustered structure, in terms of the complexity of the solution. Simulation results show that PSLL in the side clustered array can be reduced to more than −28 dB for an array of 40 elements. The PSLL was −17 dB in the case of a centrally clustered array, whereas the complexity percentage in the wholly clustered array method was 12 .5 %, while the same parameter for the partially clustered array method equaled 10%.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 1; 1--7
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testing the performance of a solar energy cooling system in Baghdad city
Autorzy:
Ahmed, Muna H.
Al-Salihi, Ali M.
Hussain, Hazim H.
Powiązania:
https://bibliotekanauki.pl/articles/35537880.pdf
Data publikacji:
2021
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
cool building
solar chimney
ground heat exchanger
weather conditions
Opis:
Renewable energy resources have become a promissory alternative to overcome the problems related to atmospheric pollution and limited sources of fossil fuel energy. The technologies in the field of renewable energy are used also to improve the ventilation and cooling in buildings by using the solar chimney and heat exchanger. This study addresses the design, construction and testing of a cooling system by using the above two techniques. The aim was to study the effects of weather conditions on the efficiency of this system which was installed in Baghdad for April and May 2020. The common weather in these months is hot in Baghdad. The test room of the design which has a size of 1 m3 was situated to face the geographical south. The test room is thermally insulated and connected to a solar chimney which generates a convection current to draw the air out of the room through a heat exchanger. The heat exchanger was submerged in a water tank of 2 m length, 1 m width and 1 m height. It was also covered with a layer of soil mixture with a thickness of 10 cm. The experiment simulates the natural conditions of a shallow water surface, connected to the room from the other side. The study results revealed that the air temperature inside the test room was lower than that of the ambient air outside. Pearson correlation coefficient showed that there was a strong direct relationship between solar radiation, temperature and wind speed from one side and the cooling efficiency from the other side. Also, there was a negative correlation between relative humidity and cooling efficiency.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2021, 30, 2; 283-292
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Lower Zab river water quality using both Canadian Water Quality Index Method and NSF Water Quality Index Method
Autorzy:
Ahmed, Sarah M.
Taha, Omer M.E.
Najemalden, Mohamed A.
Ahmed, Rehab T.
Abedulwahab, Ali A.
Powiązania:
https://bibliotekanauki.pl/articles/118599.pdf
Data publikacji:
2020
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
NSF Water Quality Index
Canadian Water Quality Index
Lower Zab river
physicochemical parameters
dissolved oxygen
biochemical oxygen demand
Opis:
Rivers are considered the most important sources of surface water on Earth. They are play a significant role in all human activities and the quality of river water is needed. Therefore, the importance of the water quality index is arising through providing data base about quality of the water source, and explain the change in the water quality over a period of time continually. This study involved determination of physicochemical and biological parameters of Lower Zab river in Kirkuk city at two different points. The objectives of the study are to assess the present water quality, through analysis of some selected water quality parameters like pH, TDS, BOD, dissolved oxygen, turbidity, EC, alkalinity, and salinity etc. and to compare the results with the Canadian Council of Ministers of the Environment and National Sanitation Foundation Water Quality Indices. Raw water samples were collected from the Lower Zab river twice a month by one sample every 15 days from each station. The water quality data include 16 different parameters. Tests were carried out following the American Public Health Association standard methods. The results show that all parameters values were within the standards of drinking water proposed by the CCME standards and Iraqi standards or the World Health Organization standards for drinking purpose, except turbidity, DO, nitrate, calcium, which were mostly higher than the standards and sometimes BOD and potassium. The results of WQI showed that the water quality at LZ3 station is lower than LZ2 station due to the polluting activity of the Lower Zab river. Furthermore, for the years 2014, 2015, and 2016, the water quality was degraded due to the ISIS war. Also, it was noted in the 2013 year that the water quality degraded more in fall and winter seasons due to that the earth has exposed to the long-dried season and then suddenly exposed to a high rainfall season which in turns leads to increase some parameters very high (i.e. turbidity). Finally, the Lower Zab river water cannot be use for drinking directly. However, a pretreatment is needed before the drinking use.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2020, 29, 2; 155-171
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of ultrasonic peening on mechanical properties of low carbon steel AISI 1020 TIG welding joints process
Autorzy:
Mohammed Ali, Ghusoon Ridha
Ridha, Ali Zuhair
Sadeq, Dina Abbas
Ebraheem, Ahmed Absullah
Atta, Amal Sadeq
Powiązania:
https://bibliotekanauki.pl/articles/27312407.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
stal niskowęglowa
śrutowanie ultradźwiękowe
właściwości mechaniczne
low carbon steel
gas tungsten arc
ultrasonic peening
mechanical properties
Opis:
In this paper, the effect of ultrasonic peening surface treatment on the mechanical properties of TIG butt weld joints of low-carbon steel (AISI 1020) was studied. A single V-angle (45°) was made on sheets of metal used then welded at constant parameters, namely: current, voltage. Wire filler ER70S-3 with argon was used to obtain many butt welding joints. Some of them were subjected to ultrasonic peening at one, two and three passes. The micro-hardness, microstructure, tensile and bending were tested. The results show increases in the tensile strength after the welding process. The test results showed improvements in the tensile strength of the weldments in comparison to the base metal. On the other hand, the tensile strength decreased with the ultrasonic process. Nevertheless, the tensile strength increased at a high number of ultrasonic passes. On the contrary, the ultrasonic process enhanced the bending strength compared to the base metal, whereas the weldments ability to bend deteriorated.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 4; 194--204
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy and environmental performance analysis of grid-connected photovoltaic systems under similar outdoor conditions in the Saharan environment
Autorzy:
Deriche, Mohammed Amine
Hafaifa, Ahmed
Tahri, Ali
Mohammedi, Kamal
Tahri, Fatima
Powiązania:
https://bibliotekanauki.pl/articles/328057.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
performance assessment
Saharan outdoor conditions
grid-connected PV
thin film photovoltaic modules
energy payback
greenhouse gases emissions
system fotowoltaiczny
energia
emisja gazów cieplarnianych
ocena wydajności
Sahara
Opis:
The aim of this paper is to present a one-year performance analysis of four grid-connected PV systems installed at Ghardaia city in Algeria’s Sahara. The grid-connected PV systems are based on four different PV module technologies which are: monocrystalline silicon (m-Si), multi-crystalline silicon (mc-Si), cadmium telluride (Cd-Te) and amorphous (a-Si) PV module technologies. The PV systems based on the thin film technologies have their performance ratio better throughout the year when the performance ratio of the mc-Si technology is better in the winter season. The a-Si PV system has its performance ratio about 6.13 % more better than mc-Si and 8.90 % better than m-Si. The AC energy produced with the a-Si PV system is 13.32 % more than what the mc-Si system produces. It was found that the a-Si PV system performs better than the other technologies under the Saharan climate conditions of Ghardaia city. The energy payback time (EPBT) and greenhouse gases (GHG) emissions of the different PV systems were analyzed. The EPBT and GHG emissions per year, vary from a minimum value of 2.8 years to a maximum value of 5.73 years and from 13.24 tons to 32.03 tons of CO2/kWh for CdTe and m-Si respectively. The CdTe PV system performs better in terms of EPBT and GHG emissions compared to the other technologies (m-Si, mc-Si and a-Si) due to its low life cycle energy requirement.
Źródło:
Diagnostyka; 2020, 21, 2; 13-23
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design optimization for the weight reduction of 2-cylinder reciprocating compressor crankshaft
Autorzy:
Arshad, Ali
Cong, Pengbo
Elsayed Elmenshawy, Adham Ahmed Awad
Blumbergs, Ilmārs
Powiązania:
https://bibliotekanauki.pl/articles/1845022.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reciprocating compressor
crankshaft optimization
weight reduction
topology optimization
stress
distribution
crank web
lightweight crankshaft design
crack modeling
static structural analysis
modal analysis
sprężarka tłokowa
optymalizacja wału korbowego
redukcja wagi
optymalizacja topologii
naprężenie
dystrybucja
wstęga korby
lekka konstrukcja wału korbowego
modelowanie pęknięć
statyczna analiza konstrukcji
analiza modalna
Opis:
This study aims to optimize the 2-cylinder in-line reciprocating compressor crankshaft. As the crankshaft is considered the "bulkiest" component of the reciprocating compressor, its weight reduction is the focus of current research for improved performance and lower cost. Therefore, achieving a lightweight crankshaft without compromising the mechanical properties is the core objective of this study. Computational analysis for the crankshaft design optimization was performed in the following steps: kinematic analysis, static analysis, fatigue analysis, topology analysis, and dynamic modal analysis. Material retention by employing topology optimization resulted in a significant amount of weight reduction. A weight reduction of approximately 13% of the original crankshaft was achieved. At the same time, design optimization results demonstrate improvement in the mechanical properties due to better stress concentration and distribution on the crankshaft. In addition, material retention would also contribute to the material cost reduction of the crankshaft. The exact 3D model of the optimized crankshaft with complete design features is the main outcome of this research. The optimization and stress analysis methodology developed in this study can be used in broader fields such as reciprocating compressors/engines, structures, piping, and aerospace industries.
Źródło:
Archive of Mechanical Engineering; 2021, LXVIII, 4; 449-471
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mining operations and geotechnical issues in deep hard rock mining – case of Boukhadra iron mine
Autorzy:
Benyoucef, Ali Ahmed
Gadri, Larbi
Hadji, Riheb
Mebrouk, Faouzi
Harkati, Elhaddi
Powiązania:
https://bibliotekanauki.pl/articles/2201672.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie
Tematy:
geomechanic
mining gallery
discontinuity
iron ore
underground mine
geomechanika
kopalnia węgla
kopalnia podziemna
nieciągłość
ruda żelaza
Opis:
Underground mining operations are a very problematic task, especially in poor geotechnical conditions. The right choice of excavation and support techniques leads to adequate and secure mining operations. This should ensure the overall stability of the underground mine with the best productivity and stability performance. In this paper, an empirical model for obtaining support systems for underground galleries was applied. Then, a numerical model for the evaluation of the performance of support measures for rock masses in the Boukhadra iron mine was introduced. Extensive field and laboratory tests were performed to obtain geological, geotechnical, and mechanical data on the entire geologic formations of the (1105 m) level. The performance of the design is supported by the selection of a common support plan between RMR, Q, and UBC systems for each geotechnical unit. Therefore, the rock masses classification based on the geo-mechanical model has determined the suitable support systems. The finite element model (FEM) was used for the analysis of rock mass behaviour, displacements, stress, and plastic point distribution. The results permit the optimization of the plastic zone thickness around the gallery. The outcomes of this study could improve the stability of the mine by choosing the right direction of excavation in consideration to the direction of the discontinuity planes. In order to choose between the current and the recommended mining operations, an equivalent calculation sequence was verified. Our study demonstrated that the consideration of discontinuity sets in the orientation of excavation highly improves the mining conditions with or without support.
Źródło:
Geomatics, Landmanagement and Landscape; 2022, 4; 27--46
2300-1496
Pojawia się w:
Geomatics, Landmanagement and Landscape
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluid dynamic and acoustic optimization methodology of a formula-student race car engine exhaust system using multilevel numerical CFD models
Autorzy:
Mohamad, Barhm
Ali, Mohammed Qasim
Neamah, Hayder Ahmed
Zelentsov, Andrei
Amroune, Salah
Powiązania:
https://bibliotekanauki.pl/articles/328318.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
engine performance
sound pressure level
computational fluid dynamics
modeling
simulation
exhaust system
wydajność silnika
poziom ciśnienia akustycznego
obliczeniowa mechanika płynów
modelowanie
symulacja
układ wydechowy
Opis:
In this work a multilevel CFD analysis have been applied for the design of an engine exhaust system include manifold and muffler with improved characteristics of noise reduction and fluid dynamic response. The approaches developed and applied for the optimization process range from the 1D to fully 3D CFD simulation, exploring hybrid approaches based on the integration of a 1D model and 3D tools. Once the best configuration has been defined, the 1D-3D approach has been adopted to confirm the prediction carried out by means of the simplified approach, studying also the impact of the new configuration on the engine performances.
Źródło:
Diagnostyka; 2020, 21, 3; 103-111
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on the structural, optical and topographical behavior of Cadmium oxide polycrystalline thin films using electrochemical depositing method at different times
Autorzy:
Abd, Ahmed N.
Dawood, Mohammed O.
Hassoni, Majid H.
Hussein, Ali A.
Powiązania:
https://bibliotekanauki.pl/articles/1192094.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Cadmium oxide
thin film
optical characteristics of film
electrochemical depositing method
Opis:
The optical and structure properties of Cadmium oxide (CdO) thin film prepared by electrochemical deposition method at different times (15, 30 and 60) min were investigated in this paper. Results of optical Transmission, absorption, reflection spectra, optical conductance, refractive index, extension coefficient, real and imaginary dielectric constants studies are reported. The optical transmittance of the CdO thin film which formed at room temperature was 20% at wavelength ≈350 nm then increases to 60% at wavelength ≈1100 nm for thin film of CdO. The band-gap was also calculated from the equation relating absorption coefficient with the wavelength. The energy band gap changes from 2.3eV (Bulk CdO) to 2.45eV (CdO thin film). The plotted graphs show the optical characteristics of the film which varied with the wavelength and the photon energy. The optical conductance and band-gap indicated that the film is transmitting within the visible range. The dielectric constant and optical conductance of the film initially decreases slowly with increase in photon energy. The extinction coefficient and refractive index of the films also evaluated, which affected with the change in transmittance. The structure of synthesised CdO thin film was analyzed by X-ray diffraction XRD which revealed that the CdO thin film are polycrystalline and have several peaks of cubic face structure. The crystallite size, dislocation density, microstrain and number of dislocations of the thin film were calculated and listed.
Źródło:
World Scientific News; 2016, 37; 249-264
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Triangular Core Rotation of a Hybrid Porous Core Terahertz Waveguide
Autorzy:
Ali, S.
Ahmed, N.
Alwee, S.
Islam, M.
Rana, S.
Bhuiyan, T.
Powiązania:
https://bibliotekanauki.pl/articles/227154.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
porous core waveguide
THz waveguide
flat EML
hybrid design
flat dispersion
triangular design
core rotation
Opis:
In this paper, we investigate the effects for rotating the triangular core air hole arrangements of a hybrid design porous core fiber. The triangular core has been rotated in anticlockwise direction to evaluate the impact on different waveguide properties. Effective Material Loss (EML), confinement loss, bending loss, dispersion characteristics and fraction of power flow are calculated to determine the impacts for rotating the triangular core. The porous fiber represented here has a hybrid design in the core area which includes circular rings with central triangular air hole arrangement. The cladding of the investigated fiber has a hexagonal array of air hole distribution. For optimum parameters the reported hybrid porous core fiber shows a flat EML of ±0.000416 cm⁻¹ from 1.5 to 5 terahertz (THz) range and a near zero dispersion of 0.4±0.042 ps/THz/cm from 1.25 to 5.0 THz. Negligible confinement and bending losses are reported for this new type of hybrid porous core design. With improved concept of air hole distribution and exceptional waveguide properties, the reported porous core fiber can be considered as a vital forwarding step in this field of research.
Źródło:
International Journal of Electronics and Telecommunications; 2017, 63, 1; 25-31
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Does managerial coaching effect subordinates’ feedback orientation? Mediating role of affective supervisory commitment
Czy coaching kierowniczy wpływa na orientację opinii podległych pracowników? Mediacyjna i emocjonalna rola nadzoru
Autorzy:
Ali, Muhammad
Arbi, Khalil Ahmed
Raza, Basharat
Malik, Sania Zahra
Sheikh, Labiba
Powiązania:
https://bibliotekanauki.pl/articles/2021573.pdf
Data publikacji:
2020
Wydawca:
Politechnika Częstochowska
Tematy:
managerial coaching
affective supervisory commitment
subordinate feedback orientation
social exchange
coaching menedżerski
emocjonalne zaangażowanie w nadzór
orientacja na informacje zwrotne podwładnych
wymiana informacji
Opis:
Managerial coaching has become a widely used human resource development strategy to improve various employee outcomes within organizations. However, existing literature lacks empirical evidence regarding the effectiveness of managerial coaching and less known about how managerial coaching influences subordinate feedback orientation through the mediating effect of employees’ commitment to the supervisor. This study uses a structured questionnaire to gather data from a cross-sectional sample of 257 employees working in the banking sector of Lahore, Pakistan, with a response rate of approximately 57%. Structural Equation Modeling (SEM) is used to test the proposed hypotheses. The results reveal that managerial coaching has a positive and direct significant impact on the subordinate feedback orientation and affective supervisory commitment. Affective supervisory commitment has a positive and direct significant relationship with the subordinate feedback orientation. Affective supervisory commitment also mediates the indirect relationship between managerial coaching and subordinate feedback orientation. This research also provides implications for managers and leaders, specifically looking to improve various employee outcomes through managerial coaching in the workplace.
Coaching menedżerski stał się szeroko stosowaną strategią rozwoju zasobów ludzkich w celu poprawy wyników różnych pracowników w organizacjach. Jednak w istniejącej literaturze brakuje dowodów empirycznych dotyczących skuteczności coachingu menedżerskiego i mniej wiadomo na temat tego, jak coaching menedżerski wpływa na orientację zwrotną podwładnych poprzez mediacyjny efekt zaangażowania pracowników wobec przełożonego. W badaniu tym zastosowano ustrukturyzowany kwestionariusz w celu zebrania danych z przekrojowej próby 257 pracowników zatrudnionych w sektorze bankowym w Lahore w Pakistanie, przy wskaźniku odpowiedzi wynoszącym około 57%. Modelowanie równań strukturalnych (SEM) służy do testowania proponowanych hipotez. Wyniki pokazują, że coaching menedżerski ma pozytywny i bezpośredni znaczący wpływ na orientację zwrotną podwładnych i afektywne zaangażowanie przełożonych. Zaangażowanie w nadzór afektywny ma pozytywny i bezpośredni znaczący związek z podporządkowaną orientacją na informację zwrotną. Zaangażowanie w nadzór afektywny pośredniczy również w pośrednim związku między coachingiem menedżerskim a orientacją zwrotną podwładnych. Badania te dostarczają również implikacji dla menedżerów i liderów, w szczególności chcących poprawić wyniki różnych pracowników poprzez coaching menedżerski w miejscu pracy.
Źródło:
Polish Journal of Management Studies; 2020, 22, 2; 9-21
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Image encryption based on Chebyshev chaotic map and S8 S-boxes
Autorzy:
Hussain, Iqtadar
Anees, Amir
Alkhaldi, Ali Hussain
Aslam, Muhammad
Siddiqui, Nasir
Ahmed, Rehan
Powiązania:
https://bibliotekanauki.pl/articles/173918.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image encryption
chaos
noise-resistant
statistical analysis
key sensitivity
Opis:
The encryption of image data is artful as compare to others due to some special characteristics such as entropy, contrast, the correlation between the pixels, intensity, and homogeneity. During encryption process, it is conventionally not easy to manage these characteristics with non-chaotic cryptosystems. Therefore for the sake of strong encryption algorithms, in last decades many cryptographers have presented invulnerable schemes for image encryption based on the chaotic maps. This manuscript aims to propose a strong encryption scheme based on a symmetric group of permutation advanced encryption standard (AES) substitution boxes and modified Chebyshev map. Principally, the secret key depends upon the parameters of Chebyshev map to create confusion in the main image and is encrypted by the scheme made from the S8 AES S-boxes and chaotic map. By this procedure, one can obtain an encrypted image that is entirely twisted. The results of analyses showed that the presented image encryption is strong and invulnerable.
Źródło:
Optica Applicata; 2019, 49, 2; 317-330
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties and fatigue life detection of copper particle filled polyester composite material under rotating bending load
Autorzy:
Hamzah, Ahmed Fadhil
Al-Turaihi, Ali S.
Hunain, Mustafa Baqir
Fadhel, Essam Zuheir
Powiązania:
https://bibliotekanauki.pl/articles/1840852.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
polymer matrix composite
particle copper reinforcement
tensile strength
fatigue
kompozyt polimerowy
wytrzymałość na rozciąganie
zmęczenie
Opis:
In the present investigation, the fatigue life detection of composite material by adding copper particle of about than 25 μm diameter with 5, 10, 15 % volume fraction, as a reinforcements into the unsaturated polyester polymer composite material on fatigue life detection of composite material were studied experimentally and numerically. Composites were made using hand lay-up technique and evaluated for mechanical and fatigue properties in accordance with ASTM standards. The experimental results of the tensile test showed that adding 15% of copper particle in unsaturated polyester gives maximum ultimate tensile stress. Fatigue tests including test rod specimens made of composite materials under completely reversed cyclic loading in a rotating cantilever reversed bending machine. It is found that, the fatigue life and fatigue strength increase with increasing in the copper percentage volume fraction in unsaturated polyester resin compared with pure polyester composites. The experimental work was compared with numerical work, which was done by using ANSYS/19 and good agreement has been found. The maximum overall difference between the experimental and numerical work was around 9 %.
Źródło:
Diagnostyka; 2021, 22, 3; 35-42
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemical Composition, Cytotoxic and Antioxidant Activities of Celosia trigyna L. Grown in Saudi Arabia
Autorzy:
El-Desouky, Samy
Abdelgawad, Ahmed
El-Hagrassi, Ali
Hawas, Usama
Kim, Young-Kyoon
Powiązania:
https://bibliotekanauki.pl/articles/895232.pdf
Data publikacji:
2019-08-30
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
GC-MS
antioxidant activity
cytotoxic activity
Celosia trigyna
flavonoid-glycosides
Opis:
The methanol extract of the aerial parts of Celosia trigyna (Amaranthaceae) was successively fractionated using n-hexane, dichloromethane, ethyl acetate and n-butanol. The cytotoxic activity of the obtained fractions was investigated using sulphorhodamine-B (SRB) assay against three carcinoma cell lines; breast adenocarcinoma (MCF-7), colorectal carcinoma (HCT-116) and hepatocellular carcinoma cells (HepG2). The dichloromethane fraction showed significant in vitro cytotoxic activities against the human cancer cell lines HCT-116 and HEP-G2 with IC50 values of 10.9 and 11.2 µg/mL, respectively, while all fractions revealed weak antioxidant activity using DPPH free radical scavenging method. The GC-MS analysis of the most cytotoxic dichloromethane fraction has resulted in the identification of 12 compounds. The main constituents were tetrahydroisoquinoline derivative (31.44%), 2,3-dimethylheptadecane (16.71%) and 3-octadecanone (15.56%). Moreover, the phytochemical study of the dichloromethane and n-butanol fractions led to the isolation and identification of five known compounds identified as β-amyrin acetate (1), acacetin 8-C-α-rhamnosyl-(1→2)-β-glucopyranoside (2), apigenin 8-C-α-rhamnosyl-(1→2)-β-glucopyranoside (3), quercetin 3-O-α-rhamnosyl-(1→6)-β-glucopyranoside (4) and 3-hydroxyglutaric acid (5).
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2019, 76, 4; 691-699
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties and fatigue life detection of copper particle filled polyester composite material under rotating bending load
Autorzy:
Hamzah, Ahmed Fadhil
Al-Turaihi, Ali S.
Hunain, Mustafa Baqir
Fadhel, Essam Zuheir
Powiązania:
https://bibliotekanauki.pl/articles/1840866.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
polymer matrix composite
particle copper reinforcement
tensile strength
fatigue
kompozyt polimerowy
wytrzymałość na rozciąganie
zmęczenie
Opis:
In the present investigation, the fatigue life detection of composite material by adding copper particle of about than 25 μm diameter with 5, 10, 15 % volume fraction, as a reinforcements into the unsaturated polyester polymer composite material on fatigue life detection of composite material were studied experimentally and numerically. Composites were made using hand lay-up technique and evaluated for mechanical and fatigue properties in accordance with ASTM standards. The experimental results of the tensile test showed that adding 15% of copper particle in unsaturated polyester gives maximum ultimate tensile stress. Fatigue tests including test rod specimens made of composite materials under completely reversed cyclic loading in a rotating cantilever reversed bending machine. It is found that, the fatigue life and fatigue strength increase with increasing in the copper percentage volume fraction in unsaturated polyester resin compared with pure polyester composites. The experimental work was compared with numerical work, which was done by using ANSYS/19 and good agreement has been found. The maximum overall difference between the experimental and numerical work was around 9 %.
Źródło:
Diagnostyka; 2021, 22, 3; 35-42
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Electrical Properties for Cantilever-Based Piezoelectric Energy Harvester
Autorzy:
Ali, Ahsan
Pasha, Riffat Asim
Sheeraz, Muhammad Abdullah
Butt, Zubair
Elahi, Hassan
Khan, Afzaal Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/102729.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
piezoelectric
micro-electromechanical systems
energy harvesting
microsystems
bimorph
systemy mikroelektromechaniczne
zbieranie energii
mikrosystemy
bimorf
Opis:
In the present era, the renewable sources of energy, e.g., piezoelectric materials are in great demand. They play a vital role in the field of micro-electromechanical systems, e.g., sensors and actuators. The cantilever-based piezoelectric energy harvesters are very popular because of their high performance and utilization. In this research-work, an energy harvester model based on a cantilever beam with bimorph PZT-5A, having a substrate layer of structural steel, was presented. The proposed energy scavenging system, designed in COMSOL Multiphysics, was applied to analyze the electrical output as a function of excitation frequencies, load resistances and accelerations. Analytical modeling was employed to measure the output voltage and power under pre-defined conditions of acceleration and load resistance. Experimentation was also performed to determine the relationship between independent and output parameters. Energy harvester is capable of producing the maximum power of 1.16 mW at a resonant frequency of 71 Hz under 1g acceleration, having load resistance of 12 kΩ. It was observed that acceleration and output power are directly proportional to each other. Moreover, the investigation conveys that the experimental results are in good agreement with the numerical results. The maximum error obtained between the experimental and numerical investigation was found to equal 4.3%.
Źródło:
Advances in Science and Technology. Research Journal; 2019, 13, 3; 76-85
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing the organizational commitment, subjective vitality and burnout effects on turnover intention in private universities
Autorzy:
Parmar, Vishnu
Channar, Zahid Ali
Ahmed, Rizwan Raheem
Streimikiene, Dalia
Pahi, Munwar Hussain
Streimikis, Justas
Powiązania:
https://bibliotekanauki.pl/articles/19322490.pdf
Data publikacji:
2022
Wydawca:
Instytut Badań Gospodarczych
Tematy:
turnover intention
job burnout
emotional exhaustion
organizational cynicism
professional efficacy
subjective vitality
affective commitment
normative commitment
continuance commitment
Opis:
Research background: Faculties of private universities are under immense working pressure, which causes stress and burnout. The job burnout triggers the psychological pressure, which increases the turnover intention.  Purpose of the article: The undertaken study aims to evaluate the scale of burnout with its three-element model, which affects faculty members of private universities of Pakistan. This research also aims to examine the mediating effect of organizational commitment (e.g., affective, normative & continuance commitments), and moderating influence of subjective vitality in a relationship of job burnout and its constituents, for example exhaustion, efficacy & cynicism, and the turnover intention. Methods: The 712 responses were collected through a structured questionnaire from the junior and senior faculty members of private universities of Pakistan. The data was examined by using second order partial least square - structural equation approach - PLS-SEM. Findings & value added: The research findings exhibited that emotional exhaustion, cynicism, and professional efficacy have a direct significant influence on job burnout. The findings further demonstrated that the job burnout has a cogent and negative impact on faculty turnover intention. The findings demonstrated that elements of organizational commitment (e.g., normative, affective & continuance commitments) have a forceful serial mediating influence between burnout & its constituents for example exhaustion, efficacy & cynicism, and turnover intention. Finally, the findings have revealed that subjective vitality has a significant and positive impact as a moderating variable in a relationship between job burnout and turnover intention. This research has a long-term theoretical contribution, as it provides a novel conceptual framework, which can be replicated in different industries. Thus, this unique model provides the solution to reduce employees' turnover for other industries as well. 
Źródło:
Oeconomia Copernicana; 2022, 13, 1; 251-286
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Climate change necessitates a change in the cultivation date of caraway (Carum carvi L.)
Autorzy:
Ibrahim, Mostafa Fathi
Ali, Muhammad Moaaz
Lamlom, Sobhi F.
Kalaji, Hazem M.
Yousef, Ahmed F.
Powiązania:
https://bibliotekanauki.pl/articles/2174359.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
climate change
condiment
leafy vegetable
sowing time
vegetative growth
volatile oil
Opis:
By 2050, global crop demand is projected to rise by 60-110%. Crop yields have also been impacted by cli mate change in some nations, and these impacts are likely to continue. To prevent the influence of climate change on crop output, it is critical to adjust planting times in weather-related open fields to meet food security concerns. Present study was carried out at Experimental Farm of Faculty of Agriculture, Al-Azhar University, Assiut, Egypt, during two successive seasons, 2019 and 2020. It was aimed to study the effect of different sowing times (1st and 15th October, 1st and 15th November), and plant spacings (25, 20, and 15 cm) on growth, fruit yield, and oil production of caraway (Carum carvi L.) plants. The results showed that sowing caraway plants on 15th October with plant spacing of 25 cm gave the highest dry weight (72.6 g∙plant-1), fresh weight (266.15 g∙plant-1), seed yield (37.43 g∙plant-1), and oil yield (0.659 cm 3∙plant-1). The maximum umbels (50.83 number per plant) and essential oil (1.78%) were also recorded in the plants receiving same treatment. On the other hand, plants sown at 15th November with spacing of 15 cm exhibited the minimum values of recorded traits. While the highest value of plant height gave with sowing caraway plants on 15th October with plant spacing of 15 cm (135.35 cm). In conclusion, the plants sowed on October 15th with a maximum plant spacing of 25 cm had the highest values of the evaluated morphological, biochemical, and yield attributes of caraway.
Źródło:
Journal of Water and Land Development; 2022, 54; 38--47
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study the Effectiveness of the Natural Lagoons for Removal of Organic Matter, Nutrients and Fecal Coliform from Urban Domestic Wastewater under Arid Climate (Morocco)
Autorzy:
Osmane, Ahmed
Zidan, Khadija
Benaddi, Rabia
Sebah, Imane
Elmouraille, Nadia
Ait Ali, Mustapha
Belmouden, Moustapha
Powiązania:
https://bibliotekanauki.pl/articles/2202383.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
natural lagoon
urban domestic wastewater
organic matter
nutrients
faecal coliforms
Opis:
Morocco is one of the countries most affected by the scarcity of water resources and the poor distribution of rainfall. Natural lagoon is the most widely used treatment process in Morocco. Indeed, Morocco is a sunny country throughout the year. The lagoon system requires minimal effort in operation and maintenance. Moreover, this system is the best process for removing bacteria indicators. For these reasons, a study of the purification performance of natural lagoons during five years, located in Chichaoua region (Morocco) was carried out. The lagoon system was monitored for five years, with measurements taken every three months at the input and output of the system. It received a hydraulic loading rate (HLR) between 1171 and 2760 m3 with an average of 2053 m3/day. The obtained results show the removal of 37% of TSS, 63% of BOD5, 60% of COD, 61% of NH4+, 37% of TP, and 6.5 log units of coliforms during the mentioned monitoring period. Thus, the effluent values do not always comply with the Moroccan water quality requirement for irrigation reuse. Additionally, the statistical analyses confirm the presence of a strong linear correlation between almost all variables in the lagoon output. Therefore, the performance efficiency of the lagoon in removing organic matter and nutrients was significantly (p < 0.05) dependent on the season. However, the fecal contamination was not significantly (p > 0.05) affected by the seasons in this study. At the end of this study a complementary treatment before the reuse of treated wastewater, was proposed.
Źródło:
Journal of Ecological Engineering; 2023, 24, 2; 196--207
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and activity evaluation of Ce-Mn-Cu mixed oxide catalyst for selective oxidation of co in automobile engine exhaust: effect of Ce/Mn loading content on catalytic activity
Autorzy:
Bilal, Yasir
Nasir, Muhammad Ali
Nasreen, Sadia
Akhter, Niaz Ahmed
Pasha, Riffat Asim
Noor, Muhammad Farhan
Powiązania:
https://bibliotekanauki.pl/articles/101992.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
base metal oxide catalyst
catalytic converter
CO sensor
CO-precipitation
catalytic activity
katalizator tlenku metalu zasadowego
katalizator
czujnik CO
strącanie CO
aktywność katalityczna
Opis:
A series of Mn-doped CeO2-CuO catalyst (CeO2-MnOx-CuO) (Ce/Mn molar ratio of 0.5, 1.0 2.0 and 3.0) were prepared using co-precipitation method for the selective oxidation of CO in automobile engine exhaust. The content of copper was 5.0 wt. % in each sample. Catalysts were installed on the automobile engine exhaust and CO amount was recorded with help of CO sensor, with and without the catalyst. The catalytic converter efficiency was estimated for each catalyst through efficiency formula. It was observed that Ce/Mn catalyst with a molar ratio of 2.0 shows the maximum efficiency (88.35%). Stability of conversion process was analyzed by plotting the CO amount with respect to time. The catalyst with Ce/Mn molar ratio of 2.0 performed the most streamline conversion process with least deviations.
Źródło:
Advances in Science and Technology. Research Journal; 2018, 12, 1; 260-266
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of tropospheric NO2 over Iraq using OMI satellite measurements
Autorzy:
Rajab, Jasim M.
Hassan, Ahmed S.
Kadhum, Jasim H.
Al-Salihi, Ali M.
San Lim, Hwee
Powiązania:
https://bibliotekanauki.pl/articles/118650.pdf
Data publikacji:
2020
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
nitrogen dioxide
air pollution
remote sensing
Baghdad
Iraq
Opis:
Tropospheric nitrogen dioxide (NO2) is a trace gas with important impact on atmospheric chemistry, human health and a key pollutant in particular cities, measured from space since the mid-1990s by the GOME, SCIAMACHY, OMI, and GOME-2 instruments. This study present ten years (monthly and yearly averaged) dataset from Ozone Monitoring Instrument (OMI) used to investigate tropospheric NO2 characteristics and variations over Iraq during 2005–2014. Annual NO2 shows an elevation from the northern to the southern and highest values was at central parts of Iraq. Monthly distributions revels higher values NO2 in winter and summer than spring and autumn seasons, and rising NO2 throughout study period over industrial and crowded urban zones. The trend analysis over Baghdad shows a linear growth rate 9.8% per year with an annual average (5.6·1015 molecules per 1 cm2). The air mass trajectory analysis as hotspot regions shows seasonal fluctuations between winter and summer seasons depend on weather conditions and topography. The increased NO2 values in winter are due to anthropogenic emissions and subsequent plumes from Europe. In addition, in summer because of hot weather and large paddy fields emissions. The lowest NO2 value was at monsoon period mostly linked to the rains. The OMI data and satellite information are able to observe the troposphere NO2 elevation at different regions.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2020, 29, 1; 3-16
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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