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Wyświetlanie 1-35 z 35
Tytuł:
Seru production as an alternative to a traditional assembly line
Autorzy:
Zwierzyński, P.
Ahmad, H.
Powiązania:
https://bibliotekanauki.pl/articles/125631.pdf
Data publikacji:
2018
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
seru production
production management
simulation
organizacja produkcyjna seru
zarządzanie produkcją
symulacja
Opis:
The article presents the concept of seru production and a simple simulation experiment to check the application effectiveness of the seru production concept in the assembly line of finished products. The article presents the concept of seru production created by Japanese electronics manufacturing companies in the 90s. The simulation experiment showed, better results using the seru production concept compared to a traditional assembly line. Three types of production cells were used and each option turned out to be better than a traditional assembly line.
Źródło:
Engineering Management in Production and Services; 2018, 10, 3; 62-69
2543-6597
2543-912X
Pojawia się w:
Engineering Management in Production and Services
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Work-related musculoskeletal disorders among information technology professionals in Riyadh, Saudi Arabia
Autorzy:
Alghadir, Ahmad H.
Khalid, Salman
Iqbal, Zaheen A.
Powiązania:
https://bibliotekanauki.pl/articles/2152945.pdf
Data publikacji:
2022
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
occupational health
IT professionals
COVID-19
Riyadh
ergonomics
desktop use
Opis:
Background This study was done to see the prevalence of work-related musculoskeletal disorders among information technology (IT) professionals in Saudi Arabia, the risk factors associated with them, their consequences, and to propose some preventive measures. Material and Methods A self-administered online questionnaire that included questions on the demographic data, job nature, medical history, work-related pain after joining information technology profession and distribution and severity of pain was sent to 250 information technology professionals working in Saudi Arabia. Results Out of 250, 202 (81%) IT professionals participated in the study. At least 62 (32%) reported that they have developed some type of musculoskeletal pain after joining their profession and 38 (61%) respondents further reported that it was so severe that they had to seek some sort of treatment for their pain. On the Visual Analog Scale ranging 0–10, 14 (23%) respondents reported that their worst ever pain was >7. Despite lower representation 67% of the females reported to develop work-related pain. Conclusions Development of work-related musculoskeletal pain among information technology professionals has been shown to affect their activities of daily living. It may even force them to change their work setting or reduce working hours. Information technology sector has rapidly grown in Saudi Arabia in the recent times and there is no data on the incidence or prevalence of such disorders among them. Role of ergonomics and counseling should be emphasized during their training that help them work effectively and efficiently. A similar large-scale study should be conducted to see the effect of lifestyle related to COVID-19 on the lives of working population especially IT professionals.
Źródło:
Medycyna Pracy; 2022, 73, 5; 397-406
0465-5893
2353-1339
Pojawia się w:
Medycyna Pracy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Air Quality Assessment and Forecasting Using Neural Network Model
Autorzy:
Hamdan, Mohammad A.
Ata, Mohammad F. Bani
Sakhrieh, Ahmad H.
Powiązania:
https://bibliotekanauki.pl/articles/1838288.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
air pollutant
ANN
MATLAB
forecasting
Opis:
Air pollution is a major obstacle faced by all countries which impacts the environment, public health, socioeconomics, and agriculture. In this study, the air pollutants in the city of Amman were presented and analyzed. Nonlinear Autoregressive Exogenous (NARX) model was used to forecast the daily average levels of pollutants in Amman, Jordan. The model was built using the MATLAB software. The model utilized a Marquardt-Levenberg learning algorithm. Its performance was presented using different indices, R2 (Coefficient of Determination), R (Coefficient of Correlation), NMSE (Normalized Mean Square Error), and Plots representing network predictions vs original data. Historical measurements of air pollutants were obtained from 4 of the Ministry of Environment (MoEnv) air quality monitoring stations in Amman. The meteorological data representing three years (2015, 2016, and 2017) were used as predictors to train the Artificial Neural Network (ANN) while the data of the year 2018 were used to test it. The results showed good performance when forecasting SO2, O3, CO, and NO2, and acceptable performance when forecasting Particulate Matter (PM10) at the given 4 locations.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 1-11
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Air Quality Assessment and Forecasting Using Neural Network Model
Autorzy:
Hamdan, Mohammad A.
Ata, Mohammad F. Bani
Sakhrieh, Ahmad H.
Powiązania:
https://bibliotekanauki.pl/articles/1838392.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
air pollutant
ANN
MATLAB
forecasting
Opis:
Air pollution is a major obstacle faced by all countries which impacts the environment, public health, socioeconomics, and agriculture. In this study, the air pollutants in the city of Amman were presented and analyzed. Nonlinear Autoregressive Exogenous (NARX) model was used to forecast the daily average levels of pollutants in Amman, Jordan. The model was built using the MATLAB software. The model utilized a Marquardt-Levenberg learning algorithm. Its performance was presented using different indices, R2 (Coefficient of Determination), R (Coefficient of Correlation), NMSE (Normalized Mean Square Error), and Plots representing network predictions vs original data. Historical measurements of air pollutants were obtained from 4 of the Ministry of Environment (MoEnv) air quality monitoring stations in Amman. The meteorological data representing three years (2015, 2016, and 2017) were used as predictors to train the Artificial Neural Network (ANN) while the data of the year 2018 were used to test it. The results showed good performance when forecasting SO2, O3, CO, and NO2, and acceptable performance when forecasting Particulate Matter (PM10) at the given 4 locations.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 1-11
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Success factors of project and process management — lessons learned from EPPM 2016
Autorzy:
Ahmad, H. S.
Bazlamit, S. M.
Jurczuk, A.
Orłowski, C.
Powiązania:
https://bibliotekanauki.pl/articles/125625.pdf
Data publikacji:
2017
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
post-conference report
materiał pokonferencyjny
Opis:
The aim of this post-conference report is to present key-issues delivered by participants of the Project and Process Management sessions (PPM) at the 7th International Conference on Engineering, Project, and Production Management (EPPM 2016). EPPM 2016 was held in Bialystok, Poland in 21-23 September. The format of the EPPM 2016 Conference involved a mixture of keynote speeches, individual presentations on topical issues, and extensive panel discussions. It featured 89 papers in five thematic sessions across the two conference days. Over 115 delegates attended EPPM 2016 from more than 20 countries across Europe, Asia, and the rest of the world.
Źródło:
Engineering Management in Production and Services; 2017, 9, 3; 7-9
2543-6597
2543-912X
Pojawia się w:
Engineering Management in Production and Services
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Driver performance through the yellow phase using video cameras at urban signalized intersections
Autorzy:
Al-Mistarehi, Bara’ W.
Alomari, Ahmad H.
Obaidat, Mohammed T.
Al-Jammal, Areen A.
Powiązania:
https://bibliotekanauki.pl/articles/2203849.pdf
Data publikacji:
2021
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
driver behavior
signalized intersections
red light running
yellow phase
zachowanie kierowcy
skrzyżowanie z sygnalizacją
przejazd na czerwonym świetle
żółta faza
Opis:
The main objective of this research is to examine the influencing parameters of driver performance through the yellow phase at urban signalized intersections with and without red-light running (RLR) cameras. Data were collected to include the intersection type, vehicle type, turning movement type, whether the vehicle position is in a platoon or not, presence of RLR cameras, green light flash devices, pedestrians, and pavement markings. A total of 2168 driver observations were extracted. Only 33.3% of the drivers stopped before the stop line, 59% of the drivers passed the intersection through the yellow phase, and 7% of the drivers committed RLR violations. The results showed that drivers were more likely to stop before the stop line through the yellow phase at locations with RLR cameras, green light flash devices, pavement markings, where pedestrians were present, and at a four-leg intersection. Chi-square tests indicated that all parameters had a significant impact on driver performance, except for the type of turning movement.
Źródło:
Transport Problems; 2021, 16, 1; 51--64
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyperelastic models for the description and simulation of rubber subjected to large tensile loading
Autorzy:
Jebur, Q.H.
Jweeg, M.J.
Al-Waily, M.
Ahmad, H.Y.
Resan, K.K.
Powiązania:
https://bibliotekanauki.pl/articles/2175788.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
rubber
carbon black
filler
hyperelastic models
Abaqus
FEM
guma
sadza
wypełniacz
modele hiperelastyczne
MES
Opis:
Purpose: Rubber is widely used in tires, mechanical parts, and user goods where elasticity is necessary. Some essential features persist unsolved, primarily if they function in excessive mechanical properties. It is required to study elastomeric Rubber's performance, which is operational in high-level dynamic pressure and high tensile strength. These elastomeric aims to increase stress breaking and preserve highly pressurised tensile strength. Design/methodology/approach: The effects of carbon black polymer matrix on the tensile feature of different Rubber have been numerically investigated in this research. Rubber's material characteristics properties were measured using three different percentages (80%, 90%and 100%) of carbon black filler parts per Hundreds Rubber (pphr). Findings: This study found that the tensile strength and elongation are strengthened as the carbon black filler proportion increases by 30%. Practical implications: This research study experimental tests for Rubber within four hyperelastic models: Ogden's Model, Mooney-Rivlin Model, Neo Hooke Model, Arruda- Boyce Model obtain the parameters for the simulation of the material response using the finite element method (FEM) for comparison purposes. These four models have been extensively used in research within Rubber. The hyperelastic models have been utilised to predict the tensile test curves—the accurate description and prediction of elastomer rubber models. For four models, elastomeric material tensile data were used in the FEA package of Abaqus. The relative percentage error was calculated when predicting fitness in selecting the appropriate model—the accurate description and prediction of elastomer rubber models. For four models, elastomeric material tensile data were used in the FEA package of Abaqus. The relative percentage error was calculated when predicting fitness in selecting the appropriate model. Numerical Ogden model results have shown that the relative fitness error was the case with large strains are from 1% to 2.04%. Originality/value: In contrast, other models estimate parameters with fitting errors from 2.3% to 49.45%. The four hyperelastic models were tensile test simulations conducted to verify the efficacy of the tensile test. The results show that experimental data for the uniaxial test hyperelastic behaviour can be regenerated effectively as experiments. Ultimately, it was found that Ogden's Model demonstrates better alignment with the test data than other models.
Źródło:
Archives of Materials Science and Engineering; 2021, 108, 2; 75--85
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Analysis of Titanium Dioxide Synthesis from Synthetic Rutile Waste using a Moderate Acid Concentration and Temperature
Autorzy:
Ahmad Mukifza, H.
Awang, H.
Yusof, S.
Farid, E.
Powiązania:
https://bibliotekanauki.pl/articles/1031724.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
synthetic rutile
titanium dioxide
caustic hydrothermal
sodium titanate
Opis:
The present study is to clarify the present influences of acid concentration and temperature of caustic hydrothermal method on extracting the titanium dioxide (TiO₂) from synthetic rutile waste. In this experimental work, the caustic hydrothermal method comprises two processes: a decomposition and the sulphate process. The extracted titanium is characterized by using a electron dispersive X-ray spectroscopy to specify its chemical composition, field emission scanning electron microscope to determine the morphology and particle size, and lastly it is the X-ray diffraction to analyse the crystallinity of extracted titanium. In this study, we found that both acid concentration and temperature affected the TiO₂ growth while the calcination process could improve the crystallinity of extracted titanium.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 833-835
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly efficient cladding pumped dual-wavelength thulium ytterbium co-doped fiber laser
Autorzy:
Latiff, A.A.
Babar, I.
Shamsudin, H.
Paul, M.
Halder, A.
Das, S.
Bhadra, S.
Ahmad, H.
Harun, S.
Powiązania:
https://bibliotekanauki.pl/articles/1058544.pdf
Data publikacji:
2016-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.55.Wd
42.60.Fc
42.70.-a
Opis:
This paper describes the all-fiber dual-wavelength thulium ytterbium co-doped fiber laser by using a newly developed octagonal shaped double-clad thulium-ytterbium co-doped fiber as gain medium in conjunction with spatial filtering effect. The thulium ytterbium co-doped fiber laser operates at wavelengths of 1990.64 nm and 1998.92 nm with a signal to noise ratio of more than 34 dB as the 980 nm multimode pump power is increased above a threshold value of 1.5 W. The slope efficiency of the dual-wavelength laser is measured to be around 26.16%, which is comparable with the conventional thulium laser pumped by 800 nm single mode pump.
Źródło:
Acta Physica Polonica A; 2016, 130, 6; 1332-1335
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Facies and diagenetic evolution of the Bathonian-Oxfordian mixed siliciclastic-carbonate sediments of the Habo Dome, Kachchh Basin, India
Autorzy:
Ahmad, A. H. M.
Irshad, R.
Bhat, G. M.
Powiązania:
https://bibliotekanauki.pl/articles/2077322.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
facies
diagenetic evolution
Habo Dome
Kachchh Basin
India
facja
diageneza
ewolucja diagenetyczna
Kachchh
Indie
Opis:
This paper examines the depositional environment and diagenetic aspects of the exposed Patcham and Chari formation within the Habo Dome. The Patcham Formation is represented by the Black Limestone Member. The Chari Formation is represented by two distinct sedimentary successions: (i) shale and carbonates, and (ii) coarse clastics. The paper describes eleven lithofacies from these successions. The depositional framework constituents of these facies have been greatly modified by diagenetic evolution through time. Two main depositional environments, i.e. foreshore intertidal and shoreface (subtidal), have dominated during their deposition. The diagenetic signatures observed within these sediments suggest early or syndepositional changes in marine phreatic and burial environments. Two phases of early mechanical compaction have largely governed porosity evolution within the limestone facies. Micritization of the allochems was caused by endolithic algae prevalent within the restricted lagoon environments with stagnant marine phreatic zone conditions. Random dissolution of microcrystalline grains has created vugs with patchy distribution reflecting neomorphism within the meteoric vadose zone. The types of cements within the sandstone facies include silica, calcite, and its replacement by Fe-calcite cement. The sandstones were deposited in a relatively low energy environment below storm wave base. The depositional conditions have controlled the early diagenesis of the sandstones which in turn have influenced their burial diagenesis.
Źródło:
Volumina Jurassica; 2015, 13, 1; 83--104
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Demarcation energy properties of regenerated fiber Bragg grating sensors in few-mode fibers
Autorzy:
Mohd Nazal, N. A.
Lai, M.-H.
Lim, K.-S.
Gunawardena, D. S.
Chong, W.-Y.
Yang, H.-Z.
Ahmad, H.
Powiązania:
https://bibliotekanauki.pl/articles/174756.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
regenerated fiber Bragg grating
thermal regeneration
thermal decay
few-mode fibers
Opis:
In this work, thermal regeneration of fiber Bragg gratings inscribed in single-mode fibers, two-mode step index fibers and four-mode step index fibers is performed, where the single-mode fibers are used as the reference in the analysis. Specifically, we investigate the behavior of the thermal decay, recovery and eventually the permanent erasure of the gratings in the temperature range from 25 to 1300°C. In the domain of demarcation energy, the thermal responses of the gratings can be normalized and they share similar characteristic curves despite the different temperature ramping rates used in the annealing treatment. It is found that the demarcation energy at the regeneration point and the attempt-to-escape frequency for each grating can be associated with the confinement factors of the fibers. The finding in this work has provided a new insight in the manufacture of regenerated fiber Bragg grating sensors by using few-mode fibers for multiparameter sensing in high temperature environments.
Źródło:
Optica Applicata; 2018, 48, 2; 263-271
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Granulometric and facies analysis of Middle–Upper Jurassic rocks of Ler Dome, Kachchh, western India: an attempt to reconstruct the depositional environment
Autorzy:
Ghaznavi, Asma A.
Quasim, M. A.
Ahmad, A. H. M.
Ghosh, Sumit K.
Powiązania:
https://bibliotekanauki.pl/articles/94565.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
grain size analysis
hydrodynamic conditions
microtexture
sedimentation
marine environment
analiza wielkości ziarna
warunki hydrodynamiczne
mikrotekstura
sedymentacja
środowisko morskie
Opis:
Grain size analysis is an important sedimentological tool used to unravel hydrodynamic conditions, mode of transportation and deposition of detrital sediments. For the present study, detailed grain size analysis was carried out in order to decipher the palaeodepositional environment of Middle–Upper Jurassic rocks of the Ler Dome (Kachchh, western India), which is further reinforced by facies analysis. Microtextures were identified as grooves, straight steps and V-shaped pits, curved steps and solution pits suggesting the predominance of chemical solution activity. Grain size statistical parameters (Graphic and Moment parameters) were used to document depositional processes, sedimentation mechanisms and conditions of hydrodynamic energy, as well as to discriminate between various depositional environments. The grain size parameters show that most of the sandstones are medium- to coarse-grained, moderately to well sorted, strongly fine skewed to fine skewed and mesokurtic to platykurtic in nature. The abundance of medium- to coarse-grained sandstones indicates fluctuating energy levels of the deposition medium and sediment type of the source area. The bivariate plots show that the samples are mostly grouped, except for some samples that show a scattered trend, which is either due to a mixture of two modes in equal proportion in bimodal sediments or good sorting in unimodal sediments. The linear discriminant function analysis is predominantly indicative of turbidity current deposits under shallow-marine conditions. The C-M plots indicate that the sediments formed mainly by rolling to bottom suspension and rolling condition in a beach subenvironment. Log probability curves show that the mixing between the suspension and saltation populations is related to variable energy conditions.
Źródło:
Geologos; 2019, 25, 1; 51-73
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Limit cycle oscillation prediction based on Finite Element-Modal approach
Autorzy:
Ahmad, K.
Wu, Z.
Rahman, H.
Powiązania:
https://bibliotekanauki.pl/articles/140294.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
geometrical nonlinearity
unsteady aerodynamics
bending mode
torsional mode
aeroelasticity
flexible structure
nieliniowość geometryczna
aerodynamika niestabilna
tryb zginania
tryb skrętny
aeroelastyczność
struktura elastyczna
Opis:
The central theme of this work was to analyze high aspect ratio structure having structural nonlinearity in low subsonic flow and to model nonlinear stiffness by finite element-modal approach. Total stiffness of high aspect ratio wing can be decomposed to linear and nonlinear stiffnesses. Linear stiffness is modeled by its eigenvalues and eigenvectors, while nonlinear stiffness is calculated by the method of combined Finite Element-Modal approach. The nonlinear modal stiffness is calculated by defining nonlinear static load cases first. The nonlinear stiffness in the present work is modeled in two ways, i.e., based on bending modes only and based on bending and torsion modes both. Doublet lattice method (DLM) is used for dynamic analysis which accounts for the dependency of aerodynamic forces and moments on the frequency content of dynamic motion. Minimum state rational fraction approximation (RFA) of the aerodynamic influence coefficient (AIC) matrix is used to formulate full aeroelastic state-space time domain equation. Time domain dynamics analyses show that structure behavior becomes exponentially growing at speed above the flutter speed when linear stiffness is considered, however, Limit Cycle Oscillations (LCO) is observed when linear stiffness along with nonlinear stiffness, modeled by FE-Modal approach is considered. The amplitude of LCO increases with the increase in the speed. This method is based on cantilevered configuration. Nonlinear static tests are generated while wing root chord is fixed in all degrees of freedom and it needs modification if one requires considering full aircraft. It uses dedicated commercial finite element package in conjunction with commercial aeroelastic package making the method very attractive for quick nonlinear aeroelastic analysis. It is the extension of M.Y. Harmin and J.E. Cooper method in which they used the same equations of motion and modeled geometrical nonlinearity in bending modes only. In the current work, geometrical nonlinearities in bending and in torsion modes have been considered.
Źródło:
Archive of Mechanical Engineering; 2018, LXV, 4; 497-514
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dye removal from textile waste water using potato starch : parametric optimization using Taguchi design of experiments
Autorzy:
Ahmad, S. W.
Zafar, M. S.
Ahmad, S.
Mohsin, M.
Qutab, H. G.
Powiązania:
https://bibliotekanauki.pl/articles/204634.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optimization
potato starch
Taguchi method
spent dye
Opis:
Typical textile waste water contains a high concentration of spent dye that can pose serious destructive impact on aquatic environment. Therefore, treatment of textile industry effluents is strictly imposed by the relevant government authorities and environmental protection agencies. During present studies, spent dye was removed using potato starch, an environmental friendly, biodegradable and cost effective coagulant, through coagulation/flocculation process. Analysis of variance (ANOVA) was performed that indicated the interaction of process parameters. It was observed that the interaction of temperature, pH and coagulant dosage were the most significant parameters that can affect the coagulation/flocculation process. So, temperature, pH and coagulant dosage were optimized by Taguchi optimization technique. The results indicated that maximum dye (about 27%) was removed when temperature, pH and coagulant dosage were kept at 55°C, 10 and 0.5% (w/v), respectively.
Źródło:
Archives of Environmental Protection; 2018, 44, 2; 26-31
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary Investigation on the Ballistic Limit of Ultra High Molecular Weight Polyethylene Unidirectional Coated Fabric System
Wstępne badania balistyczne pakietów z pokrywanych tkanin typu UD wykonanych z polietylenu o ultra wysokiej masie cząsteczkowej
Autorzy:
Ahmad, M. R.
Hassim, N.
Ahmad, W. Y. W.
Samsuri, A.
Yahya, M. H. M.
Powiązania:
https://bibliotekanauki.pl/articles/231828.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
unidirectional fabric
natural rubber latex
ballistic limit
energy absorption
pokrywana tkanina
kauczuk naturalny
lateks
ograniczenia balistyczne
absorpcja energii
Opis:
This paper reports an investigation on the ballistic impact performance of high strength unidirectional (UD) fabrics UHMWPE coated with natural rubber latex (NRL). The effects of adding calcium carbonate in the NRL on the ballistic impact were also studied. Several NRL coated UD fabrics were assembled together with neat UD fabrics in a 12-ply fabric system. The ballistic limit and energy absorption of the fabric systems were determined. Results of the ballistic limit test showed that the NRL coated UD fabrics gave some positive effects in enhancing the ballistic impact performance of the fabric systems in comparison with all-neat fabric systems. Several mechanisms of energy absorption were observed on the fabric systems which include burn marks, fibre stretching, fibre pull-out, shearing, delamination of fabric plies for completely penetrated fabric systems and a punched-out effect on the back ply of partially penetrated fabric systems.
Badania dotyczyły efektu uderzenia pocisku w balistyczny pakiet wykonany z pokrywanych naturalną gumą tkanin typu UD wykonanych z polietylenu o ultra wysokiej masie cząsteczkowej. Dodatkowo badano wpływ dodania węglanu wapnia do kauczuku naturalnego. W pakietach składano tkaniny powlekane i niepowlekane w systemy zawierające do 12 warstw. Określano limit balistyczny i energię absorpcji uzyskanych pakietów. Wyniki badań wskazują, że powlekanie warstw gumą naturalną daje pozytywne efekty poprawiając zachowanie pakietu na uderzenie pocisku. Obserwowano pojawianie się przypalenia pakietów, rozciąganie włókien, wyciąganie włókien, ścinanie, delaminację pakietów aż do całkowitej penetracji wszystkich warstw systemu.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 3 (99); 89-94
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phenolic, carotenoid, ascorbic acid contents and their antioxidant activities in bell pepper
Autorzy:
Akhtar, M.
Ahmad, A.
Masud, T.
Wattoo, F.H.
Powiązania:
https://bibliotekanauki.pl/articles/12661132.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
plant cultivation
sweet pepper
chemical composition
phenolic acid
carotenoid content
ascorbic acid content
antioxidant activity
Opis:
Essential nutritional components are quantified in the study in addition to major antioxidants, carotenoids, phenols and flavonoids. Their antioxidant activities were also analyzed using DPPH, ABTS and hydrogen peroxide radical scavenging activities and by determining their iron reducing power. Results indicated that the highest quantity of nutritional and antioxidant components was obtained in red variety (4.63 mg/g ascorbic acid, 10.32 mg/g total carotenoid content, 61.50 mg/g total flavonoid content, 310.27 mg/g total phenolic content) followed by orange, yellow and green varieties. Similar trend was observed while analyzing their antioxidant activities by different methods. In studying correlation between components and antioxidant activity, a strong correlation was obtained for ABTS radical scavenging activity with total phenolic content (R2 = 0.722) and total carotenoid contents (R2 = 0.709), while moderate correlation was observed for ABTS radical scavenging activity with total flavonoid contents (R2 = 0.517) and ascorbic acid (R2 = 0.673).
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2019, 18, 1; 13-21
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production of Shape Memory Alloy Core-Sheath Friction Yarns
Wytwarzanie przędz rdzeniowych z udziałem drutów posiadających pamięć kształtu
Autorzy:
Ahmad, M. R.
Yahya, M. H. M.
Hassan, M. R.
Salleh, J.
Ahmad, W. Y. W.
Hassim, N.
Powiązania:
https://bibliotekanauki.pl/articles/233234.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
shape memory alloy
DREF 3000 spinning system
conductive yarn
druty z pamięcią kształtu
przędzarka DREF 3000
przędze rdzeniowe
wpływ parametrów przędzenia
pamięć kształtu przędzy
Opis:
This paper describes some studies on the development of shape memory alloy (SMA) coresheath friction yarns. SMA wires for actuating purposes were utilised as a conductive element in the core-sheath friction yarn. A DREF 3000 friction spinning machine was used to produce the yarns. The conductive yarn was spun with the SMA actuator wire at the core and 100% cotton fibers in the second layer as the sheath producing a yarn called SMA core-sheath friction yarn (SMA CSFY). During spinning, the core-sheath ratio and spinning drum speeds were varied. The main purposes of the study were to evaluate the SMA CSFY single yarn tensile strength and its actuating performance against changes in the spinningprocess parameters. The results showed that SMA CSFY with the highest spinning drumspeed and 60% core gave the highest tensile strength and fastest actuation performance.
Badania dotyczyły opracowania przędz rdzeniowych z udziałem składnika posiadającego pamięć kształtu. Druty z pamięcią kształtu zostały zastosowane jako elementy elektrycznie przewodzące. Do produkcji tych przędz zastosowano przędzarkę DREF 3000. Przędze przewodzące były produkowane z rdzeniem z drutów o pamięci kształtu oraz otoczką z włókien bawełnianych (100%). Przędzenie przeprowadzano przy zmianie prędkości bębna przędącego. Głównym celem badań była ocena właściwości wytrzymałościowych otrzymanej przędzy oraz wpływ parametrów przędzenia na pamięć kształtu przędzy. Wyniki badań wskazują, że przędze otrzymane przy najwyższych prędkościach bębna przędącego i udziale rdzenia 60% posiadają najlepsze właściwości wytrzymałościowe i korzystne reakcje na zmianę kształtu.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 3 (99); 68-72
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phosphate-induced changes in fatty acid biosynthesis in Chlorella sp. KS-MA2 strain
Autorzy:
Ahmad, A.
Osman, S.M.
Cha, T.S.
Loh, S.H.
Powiązania:
https://bibliotekanauki.pl/articles/80623.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2016, 97, 4
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jurassic rhynchonellide brachiopods from the Jordan Valley
Autorzy:
Feldman, H.R.
Schemm-Gregory, M.
Ahmad, F.
Wilson, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/23239.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Jurassic
rhynchonellid brachiopod
brachiopod
Jordan Valley
Brachiopoda
Rhynchonellida
Mughanniyya Formation
Opis:
Jurassic rhynchonellide brachiopods from the Jordan Valley are herein revised and new taxa are added to the faunal list. In this study of Jurassic rhynchonellides from Wadi Zarqa, northwestern Jordan, we recognize the following taxa: Eurysites rotundus, Cymatorhynchia quadriplicata, Daghanirhynchia triangulata, D. angulocostata, Pycnoria magna, Schizoria elongata, and Schizoria cf. intermedia. The following new taxa are described: Daghanirhynchia susanae sp. nov. and Amydroptychus markowitzi sp. nov. The Middle Jurassic Mughanniyya Formation of northwest Jordan is dominated by limestone beds. The sedimentary environment is interpreted as neritic, light, and nutrient−rich resulting in high faunal diversity. The high rhynchonellide endemism of this fauna is yet another confirmation of pronounced Middle Jurassic endemism along the southern Tethyan margin of the Ethiopian Province. Brachiopods of the Jordanian Mughanniyya Formation can be correlated with the fauna of the Aroussiah Formation in Sinai and the Zohar and Matmor formations in Southern Israel.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and properties of vinylpyrrolidone/ (trimethoxysilyl)propyl methacrylate gels containing different amounts of crosslinking agent
Synteza i właściwości żelu N-winylopirolidon/metakrylan3-(trimetoksysililo)propylu z różną zawartością czynnika sieciującego
Autorzy:
Mohammed, A. H.
Ahmad, M. B.
Ibrahim, N. A.
Zainuddin, N.
Powiązania:
https://bibliotekanauki.pl/articles/947044.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
high conversion copolymers
swelling parameters
mechanical properties
oxygen permeability
crosslinking density
kopolimery o wysokim stopniu konwersji
parametry pęcznienia
właściwości mechaniczne
przepuszczalność tlenu
gęstość sieciowania
Opis:
High conversion copolymers containing 90 wt % of N-vinylpyrrolidone (NVP) and 10 wt % of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) with 0, 1, 2, 3 and 4 wt % (in conversion to mass of NVP/TMSPM) of ethylene glycol dimethacrylate (EGDMA) as crosslinker have been successfully synthesized. Proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the resulting copolymers. The effect of EGDMA amount on the mechanical and thermal properties, swelling parameters, clarity, and oxygen permeability of the prepared xerogels and hydrogels were studied. 3 wt % of EGDMA is required to obtain clear xerogels and hydrogels. The water content (EWC), volume fraction of polymer (φ2) and weight loss during swelling decrease with increasing EGDMA content. Young’s and shear modulus (E and G) increase as EGDMA content increases, the values of E and G are 0.570–3.531 MPa and 0.217–1.359 MPa, respectively. The hydrogels were characterized in terms of modulus crosslinking density (ve and vt) and polymer-solvent interaction parameters (χ). The results are 0.220–0.613 mol/dm3 for ve, 0.105–0.441 mol/dm3 for vt, and 0.595–0.822 for χ. Thermal properties enhance by adding EGDMA whereas the oxygen permeability (P) of hydrogels decreases from 48.6 to 44.3 as water content decrease from 70.3 to 55.1.
Kopolimery zawierające 90 % mas. N-winylopirolidonu (NVP) i 10 % masmetakrylanu 3-(trimetoksysililo)propylu (TMSPM) z udziałem 0, 1, 2, 3 i 4 % mas. (w przeliczeniu na masę NVP/TMSPM) dimetakrylanu glikolu etylenowego (EGDMA) jako środka sieciującego zsyntetyzowano z wysokim stopniem konwersji. Otrzymane kopolimery charakteryzowano metodami protonowego rezonansu jądrowego (H1 NMR) i spektroskopii w podczerwieni (FT-IR). Badano wpływ udziału środka sieciującego na właściwości mechaniczne i termiczne, parametry pęcznienia, klarowność i przepuszczalność tlenu wytworzonych hydro- i kserożeli. Stwierdzono, że dodatek już 3 % mas. EGDMA wystarcza do uzyskania klarownego żelu, a w miarę zwiększania zawartości EGDMA zmniejsza się zawartość wody (EWC), ułamek objętości polimeru (φ2) oraz strata masy w procesie pęcznienia żelu NVP/TMSPM. Wartość modułu zarówno Younga (E), jak i ścinania (G) zwiększa się (E = 0,570–3,531 MPa, G = 0,217–1,359 MPa) wraz ze wzrostem udziału EGDMA w kompozycji. Wytworzone hydrożele charakteryzowano za pomocą modułów gęstości sieciowania (ve = 0,220–0,613 mol/dm3, vt = 0,105–0,441 mol/dm3) i parametru oddziaływania polimer-rozpuszczalnik (χ = 0,595–0,822). Właściwości termiczne otrzymanych hydrożeli zawierających EGDMA poprawiły się wraz ze zmniejszeniem zawartości wody (70,3–55,1), natomiast przepuszczalność tlenu się pogorszyła (P = 48,6–44,3).
Źródło:
Polimery; 2018, 63, 9; 577-585
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and monomer reactivity ratios of acrylamide with 3-(trimethoxysilyl)propyl methacrylate and tris(methoxyethoxy)vinylsilane copolymers
Współczynniki reaktywności monomerów w syntezie kopolimerów akryloamidu, metakrylanu 3-(trimetoksysililo)propylu i tris(metoksyetoksy)-winylosilanu
Autorzy:
Mohammed, A. H.
Ahmad, M. B.
Ibrahim, N. A.
Zainuddin, N.
Powiązania:
https://bibliotekanauki.pl/articles/947173.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
vinylsilane monomers
acrylamide
reactivity ratios
sequence distribution
sekwencja monomerów
Opis:
Copolymers of acrylamide (AM) with 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) and tris(methoxyethoxy)vinylsilane (TMEVS) with different compositions were synthesized at low conversion by free radical polymerization in dimethylformamide (DMF) using benzoyl peroxide (BPO) as an initiator. The copolymers were characterized by Fourier transform infrared spectroscopy (FT-IR), and their thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The copolymers composition was determined by elemental analysis. The monomer reactivity ratios were estimated by linearization methods proposed by Fineman-Ross and Kelen-Tudos, the intersection method proposed by Mayo-Lewis and nonlinear method proposed by curve fitting procedure. The derived reactivity ratios (r1, r2) are: 1.87, 0.80 for TMSPMA-co-AM and 0.22, 1.21 for TMEVS-co-AM. Both copolymers formed blocks of one of the monomer units. The microstructure of copolymers and sequence distribution of monomers in the copolymers were calculated by statistical method based on the average reactivity ratios and found that these values are in agreement with the derived reactivity ratios.
Kopolimery akryloamidu (AM) z metakrylanem 3-(trimetoksysililo)propylu (TMSPMA) itris(metoksyetoksy)winylosilanem (TMEVS), o różnych składach, zsyntetyzowano w warunkach małej konwersji metodą wolnorodnikowej polimeryzacji w dimetyloformamidzie (DMF), z zastosowaniem nadtlenku benzoilu (BPO) jako inicjatora. Otrzymane kopolimery charakteryzowano za pomocą spektroskopii w podczerwieni z transformacją Fouriera (FT-IR), różnicowej kalorymetrii skaningowej (DSC) oraz analizy termograwimetrycznej (TGA). Skład kopolimerów ustalono metodą analizy elementarnej. Współczynniki reaktywności monomerów oszacowano metodami linearyzacji zaproponowanymi przez: Finemana-Rossa, Kelena-Tudosa, Mayo-Lewisa i metodą nieliniową z zastosowaniem procedury dopasowania krzywej. Otrzymane współczynniki reaktywności (r1, r2) wynosiły: 1,87 i 0,80 dla TMSPMA-co-AM oraz 1,21 i 0,22 dla TMEVS-co-AM. Oba kopolimery miały budowę złożoną zbloków utworzonych z jednostek monomerów składowych. Mikrostrukturę oraz sekwencję monomerów w kopolimerach wyznaczono metodą statystyczną na podstawie średnich współczynników reaktywności. Stwierdzono zgodność obliczeń z wartościami otrzymanymi doświadczalnie.
Źródło:
Polimery; 2016, 61, 11-12; 758-765
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Wildlife Conservation Awareness and practices in some selected secondary school around Kainji Lake National Park, Nigeria
Autorzy:
Akande, O. A.
Ahmad, Y. A.
Yusuf, H. O.
Akinade, T. G.
Powiązania:
https://bibliotekanauki.pl/articles/1076522.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Awareness
Practices and Secondary school
Wildlife conservation
Opis:
One of the challenges facing wildlife conservation is how to change the way people perceive wildlife. Therefore this study examine wildlife conservation awareness and practices in some selected secondary school around Kainji Lake National Park. Data was collected through the use of pre tested structured questionnaires among six selected secondary school in the study area. The sample of the research was one hundred (100) respondents. Data was analysis using descriptive statistics. The findings reveals that majority of the respondents (74%) are male and age group 15-20 years had the highest with 43%. 63% of the respondents are aware of wildlife conservation in the study area and majority (66%) of the respondent has not visit the Kainji Lake National Park. 50% of the respondents had about wildlife through direct communication. 63% and 80% of the respondents are willing and are ready to support wildlife conservation in the study area. The finding still reveal that awareness is still lacking in most schools among the communities. Therefore more wildlife conservation awareness is needed in our various schools so as to get the interest of the students when they are still young so that generation coming will also be thought.
Źródło:
World Scientific News; 2019, 115; 91-103
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Theoretical Study of Magnetic Behavior of Diamond Doped with Transition Metals
Autorzy:
Hussain, F.
Ullah, M.
Ullah, H.
Rashid, M.
Imran, M.
Ahmad, E.
Powiązania:
https://bibliotekanauki.pl/articles/1399279.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Kt
75.10.Pq
75.30.Hx
Opis:
We study the magnetic behavior of the diamond system. In this system diamond bulk is involved which is doped with different transition metals, namely Cu, Cd, Hg, and Zn. The VASP code is employed for all calculations which are based on density functional theory. The substitutional point defects is introduced in the diamond bulk and occupied by the transition metals. Results exhibit that all transition metals show ferromagnetism behavior and Cu is a good advocate of conductivity among all transition metals. The range of magnetic moments is 2.89, 1.99, 1.96, and 1.80 $μ_{B}$ per Cu, Cd, Hg, and Zn atom in diamond bulk, respectively. Strong magnetic behavior points out that these materials could be used for spintronics.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 823-826
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deposition of a polymeric porous superhydrophobic thin layer on the surface of poly(vinylidenefluoride) hollow fiber membrane
Autorzy:
Ahmad, A. L.
Mohammed, H. N.
Ooi, B. S.
Leo, C. P.
Powiązania:
https://bibliotekanauki.pl/articles/778912.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Superhydrophobic layer
PVDF
Gas-liquid contactor
CO2
porous
Opis:
Porous superhydrophobic layer of low-density polyethylene (LDPE) was created by a simple approach on the Poly(vinylidenefluoride) (PVDF) hollow fiber membranes. Acetone and ethanol mixtures with different volume ratios were used as the non-solvent on the coating surface. A 5:1 (v/v) acetone/ethanol ratio provided a porous surface with a 152° ± 3.2 water contact angle. The high contact angle could reduce membrane wettability for better carbon dioxide capture when the membrane was used as gas-liquid contactor in absorption processes. To assess the effect of the created superhydrophobic layer, the pristine and modified membranes were tested in a CO2 absorption system for ten days. The results revealed that the absorption flux in the modified membrane was higher than that of pristine membrane.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 3; 1-6
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Weave Design and Yarn Types on Mechanical and Surface Properties of Woven Fabric
Wpływ wzoru tkackiego i rodzaju przędzy na mechaniczne i powierzchniowe właściwości tkaniny
Autorzy:
Azeem, M.
Ahmad, Z.
Wiener, J.
Fraz, A.
Siddique, H. F.
Havalka, A.
Powiązania:
https://bibliotekanauki.pl/articles/231703.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
PC yarn
ring spun
open-end
weave design
abrasion
pilling
przędza PC
system obrączkowy
splot płócienny
splot atłasowy
wytrzymałość na zerwanie
Opis:
The purpose of this study was to examine the effect of spinning technologies and weave design on fabric mechanical and surface properties. For this purpose, ring spun (combed, carded) and open-end (OE) techniques were used to manufacture yarns of polyester cotton (50:50) which were used in the weft, and 100% cotton yarn in the warp. Plain, twill, and satin weave designs were selected to construct woven samples on a projectile loom. The variation in fabric tensile strength is obvious with respect to weave designs. Higher interlacing of yarn produces more crimp in the load bearing, which may cause lower breaking strength and fewer broad floats. The mechanical and surface properties of these fabric samples were investigated and statistical analysis was performed, which showed a significant effect of the spinning technique and weave design on these properties.
Celem tego badania było zbadanie wpływu technologii przędzenia i splotu na właściwości mechaniczne i powierzchniowe tkaniny. Przy zastosowaniu systemu obrączkowego i bezwrzecionowego wytworzono przędzę bawełniano-poliestrową(50:50) i przędzę w 100% bawełnianą. Następnie na krośnie chwytakowym wytworzono tkaniny o splotach płóciennym i atłasowym. Różnice w wytrzymałości na rozciąganie tkanin są oczywiste w odniesieniu do wzorów splotów. Większe przeplatanie przędzy powoduje więcej karbikowania, co może powodować niższą wytrzymałość na zerwanie. Zbadano mechaniczne i powierzchniowe właściwości próbek tkanin i wykonano analizę statystyczną, która wykazała istotny wpływ techniki przędzenia i rodzaju splotu na właściwości mechaniczne i powierzchniowe tkanin.
Źródło:
Fibres & Textiles in Eastern Europe; 2018, 1 (127); 42-45
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, characterization and thermal polymerization of new 3,4-dihydro-2H-1,3-naphthoxazine monomers
Synteza, charakterystyka i polimeryzacja termiczna nowych monomerów 3,4-dihydro-2H-1,3-naftoksazynowych
Autorzy:
Gabbas, A. U. G.
Ahmad, M. B. H.
Zainuddin, N.
Ibrahim, N. A.
Powiązania:
https://bibliotekanauki.pl/articles/946991.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
1,3-naphthoxazine
polynaphthoxazine
thermal polymerization
thermal properties
1,3-naftoksazyna
polinaftoksazyna
polimeryzacja termiczna
właściwości termiczne
Opis:
Two new 1,3-naphthoxazine monomers (M-A and M-B) were synthesized via a modified stepwise procedure in which methylene bromide was used for the ring-closure reaction. Condensation of 2-hydroxy-1-naphthaldehyde with 1,6-hexamethylenediamine or 1,4-phenylenediamine gives imine compounds, which were converted to 2-hydroxynaphthylamines by reduction with NaBH4 in methanol. Ring-closure reaction between the 2-hydroxynaphthylamines and methylene bromide results in the formation of 1,3-naphthoxazine monomers M-A or M-B with good yields. The structures of the synthesized monomers were confirmed using different spectroscopic techniques (including FT-IR, 1H NMR and 13C NMR), mass spectrometry, and elemental analysis. Thermal polymerization of the monomers was investigated by FT-IR and differential scanning calorimetry (DSC). Both the 1,3-naphthoxazine monomers undergo ring-opening polymerization, leading to the formation of the corresponding polynaphthoxazines [P(M-A) and P(M-B)]. The thermal stability of the polynaphthoxazines was thereafter studied by thermogravimetric analysis (TGA).
Za pomocą zmodyfikowanej trójetapowej syntezy, w której do reakcji zamknięcia pierścienia zastosowano bromek metylenu, otrzymano dwa nowe monomery 1,3-naftoksazyny (M-A i M-B). Kondensacja 2-hydroksy-1-naftaldehydu z 1,6-heksametylenodiaminą lub 1,4-fenylenodiaminą pozwala na wytworzenie związków iminowych, które następnie przez redukcję NaBH4 w metanolu są przekształcane w 2-hydroksynaftylaminy. Reakcja zamknięcia pierścienia pomiędzy 2-hydroksynaftylaminą i bromkiem metylenu prowadzi do utworzenia z dobrymi wydajnościami monomerów 1,3-naftoksazyny M-A i M-B. Struktury zsyntetyzowanych monomerów potwierdzono stosując różne techniki spektroskopowe, spektroskopię masową oraz analizę elementarną. Polimeryzację termiczną monomerów badano za pomącą spektroskopii w podczerwieni z transformatą Fouriera (FT-IR) i różnicowej kalorymetrii skaningowej (DSC). Oba monomery 1,3-naftoksazyny uległy polimeryzacji z otwarciem pierścienia dając odpowiednie polinaftoksazyny [P(M-A) i P(M-B)]. Za pomocą analizy termograwimetrycznej (TGA) zbadano stabilność termiczną otrzymanych polinaftoksazyn.
Źródło:
Polimery; 2017, 62, 2; 86-92
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carbon emissions, energy use, gross domestic product and total population in China
Autorzy:
Ahmad, M.
Hengyi, H.
Rahman, Z. U.
Khan, Z. U.
Khan, S.
Khan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/96260.pdf
Data publikacji:
2018
Wydawca:
Fundacja Ekonomistów Środowiska i Zasobów Naturalnych
Tematy:
energy consumption
carbon emission
GDP
Granger causality
ARDL
EKC
zużycie energii
emisja dwutlenku węgla
PKB
przyczynowość w sensie Grangera
Opis:
The current study explores the impact of energy consumption, total population, gross domestic product on carbon emissions by utilizing time series data of 1971-2013 for China. Earlier studies concentrated on testing the present form of an environmental Kuznets curve not taking total population in a model. Specifically, this study focuses on analyzing the long run existence of environmental Kuznets curve. The methodology of auto regressive distributed lag model is utilized. The quadratic linkage between national income and emissions of carbon have been detected, confirming the presence of long run linkage between quadratic national income and emissions of carbon. Granger causality test divulge one-way causality between gross domestic product and carbon emissions. The empirical findings also reveal that the energy use and national income are important factors of carbon emanations in the long run. Total population has an insignificant positive influence on emissions of carbon. It is suggested that government should focus to extract that substitute sources of energy which is more environmental friendly.
Źródło:
Ekonomia i Środowisko; 2018, 2; 32-44
0867-8898
Pojawia się w:
Ekonomia i Środowisko
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of optimum temperature, humidity, and vapour pressure deficit for microclimate evaluation and control in greenhouse cultivation of tomato: a review
Autorzy:
Shamshiri, R.R.
Jones, J.W.
Thorp, K.R.
Ahmad, D.
Che Man, H.
Taheri, S.
Powiązania:
https://bibliotekanauki.pl/articles/26637.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Źródło:
International Agrophysics; 2018, 32, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of pre-sowing magnetic field doses through RSM in pea
Autorzy:
Iqbal, M.
Ahmad, I.
Hussain, S.M.
Khera, R.A.
Bokhari, T.H.
Shehzad, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/25738.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Opis:
Seed pre-sowing magnetic field treatment was reported to induce biochemical and physiological changes. In the present study, response surface methodology was used for deduction of optimal magnetic field doses. Improved growth and yield responses in the pea cultivar were achieved using a rotatable central composite design and multivariate data analysis. The growth parameters such as root and shoot fresh masses and lengths as well as yield were enhanced at a certain magnetic field level. The chlorophyll contents were also enhanced significantly vs. the control. The low magnetic field strength for longer duration of exposure/ high strength for shorter exposure were found to be optimal points for maximum responses in root fresh mass, chlorophyll ‘a’ contents, and green pod yield/plant, respectively and a similar trend was observed for other measured parameters. The results indicate that the magnetic field pre-sowing seed treatment can be used practically to enhance the growth and yield in pea cultivar and response surface methodology was found an efficient experimental tool for optimization of the treatment level to obtain maximum response of interest.
Źródło:
International Agrophysics; 2013, 27, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effectiveness of fMRI Data when Combined with Polygraph Data
Эффективность сочетания данных фМРТ с данными полиграфа
Autorzy:
Gordon, Nathan J.
Mohamed, Feroze B.
Platek, Steven M.
Ahmad, Harris
Williams, J. Michael
Faro, Scott H.
Powiązania:
https://bibliotekanauki.pl/articles/523470.pdf
Data publikacji:
2018
Wydawca:
Krakowska Akademia im. Andrzeja Frycza Modrzewskiego
Tematy:
Integrated Zone Comparison Technique
Polygraph
ASIT PolySuite Scoring Algorithm
Horizontal Scoring System
fMRI
Pneumo
Electro-dermal Response
Cardio
Opis:
The Integrated Zone Comparison Technique (IZCT) was utilized with computerized polygraph instrumentation and the Academy for Scientific Investigative Training’s Horizontal Scoring System ASIT PolySuite algorithm, as part of a blind study in the detection of deception. This paper represents a synergy analysis of combining fMRI only deception data with each of the three individual physiological parameters that are used in polygraph. They include the electro-dermal response (EDR), pneumo, and cardio measurements. In addition, we compared the detection accuracy analysis using each single parameter by itself. The fMRI score and each individual polygraph parameter score on individual subjects were averaged to establish an overall score.
Źródło:
European Polygraph; 2018, 12, 1(43); 19-25
1898-5238
2380-0550
Pojawia się w:
European Polygraph
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Introducing key advantages of intensified flotation cells over conventionally used mechanical and column cells
Autorzy:
Hassanzadeh, Ahmad
Safari, Mehdi
Khoshdast, Hamid
Güner, Mustafa K.
Hoang, Duong H.
Sambrook, Tim
Kowalczuk, Przemyslaw B.
Powiązania:
https://bibliotekanauki.pl/articles/2146874.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
pneumatic flotation cells
energy input
mean particle retention time
fine particles
bubble size distribution
Opis:
The present paper introduces the key advantages of ImhoflotTM, JamesonTM, and RefluxTM flotation cells over the conventionally used mechanical and column cells from different perspectives. The impact of slurry mean retention time, bubble size distribution, and energy input was studied for all cell types. The mean retention time of laboratory scale ImhoflotTM (V030-cell) and RefluxTM flotation cells (RFC100) were measured experimentally using KCl as a tracer. Also, initially a statistical and practical overview of previously installed ImhoflotTM, and JamesonTM cells was presented in this work. It was found that more industrial data is available for the JamesonTM cell. The diagnostic results showed that RefluxTM, JamesonTM, and ImhoflotTM functionally operate similarly based on providing intensive turbulence in the downcomer. They were initially applied to the Australian and the UK coal industries and installed in the cleaning stage of flotation circuits, while there are now more applications in a wide variety of minerals across the world in different flotation stages. First pilot trials on a Russian gold ore were reported operating both JamesonTM and ImhoflotTM cells at the rougher-scalper and cleaner stages providing superior results using the ImhoflotTM cell as rougher-scalper and the JamesonTM at the cleaner. Formation of sub-micron and micron-sized bubbles, effective hydrodynamic characteristics, and low capital and operating costs were reported as major advantages of intensified flotation cells over the conventionally used ones in improving the recoverability of ultra-fine particles. Literature data showed that these cells provide greater gas-hold-up values (40-60%) over the mechanical (5-20%) and column cells (5-25%) with substantially lower power inputs. It was indicated that low mean slurry retention time could lead to a potential enhancement in their throughputs, but further industrial measurements are required to prove this statement. The RefluxTM cell showed a plug-flow mixing regime, while ImhoflotTM V-Cell followed the trend of perfect mixing and plug-flow dispersion regimes.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 5; art. no. 155101
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antibacterial activity of iron oxide nanoparticles synthesized by co-precipitation technology against Bacillus cereus and Klebsiella pneumoniae
Autorzy:
Ansari, S. A.
Oves, M.
Satar, R.
Khan, A.
Ahmad, S. I.
Jafri, M. A.
Zaidi, S. K.
Algahtani, M. H.
Powiązania:
https://bibliotekanauki.pl/articles/778380.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
antibacterial activity
co-precipitation
iron oxide nanoparticles
Klebsiella pneumoniae
physico-chemical characterization
Opis:
The present study investigates the synthesis and characterization of iron oxide nanoparticles (Fe3 O4 -NPs) for their antibacterial potential against Bacillus cereus and Klebsiella pneumonia by modified disc diffusion and broth agar dilution methods. DLS and XRD results revealed the average size of synthesized Fe3 O4 -NPs as 24 nm while XPS measurement exhibited the spin-orbit peak of Fe 2p3/2 binding energy at 511 eV. Fe3 O4 -NPs inhibited the growth of K. pneumoniae and B. cereus in both liquid and soild agar media, and displayed 26 mm and 22 mm zone of inhibitions, respectively. MIC of Fe3 O4 -NPs was found to be 5 μg/mL against these strains. However, MBC for these strains was observed at 40 μg/mL concentration of Fe3 O4 -NPs for exhibiting 40–50% loss in viable bacterial cells and 80 μg/mL concentration of Fe3 O4 -NPs acted as bactericidal for causing 90–99% loss in viability. Hence, these nanoparticles can be explored for their additional antimicrobial and biomedical applications.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 4; 110-115
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extraction, Chemical Composition and Antidiabetic Potential of Crude Polysaccharides from Centella asiatica (L.) Urban
Autorzy:
Li, Meng
Shahid, Muhammad
Zhang, Xiaobin
Law, Douglas
Mackeen, Mukram M.
Teh, Arnida H.
Najm, Ahmad A.
Fazry, Shazrul
Othman, Babul A.
Powiązania:
https://bibliotekanauki.pl/articles/31341117.pdf
Data publikacji:
2024-05-24
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
alcohol insoluble residue
antidiabetic
mineral elements
monosaccharide composition
response surface methodology
Opis:
The global prevalence of diabetes mellitus (DM) is escalating, posing a significant challenge to human healthcare systems. In the present study, mineral and monosaccharide compositions, and antidiabetic potential of polysaccharide fractions separated from Centella asiatica (L.) leaves (CAL) were assessed. Initial single-factor experiments identified key extraction parameters, further optimized through response surface methodology (RSM) with optimal conditions determined as a liquid-to-solid ratio of 24.43:1 (mL/g), extraction time of 60.76 min, and a temperature of 83.31℃. Alcohol insoluble residue (AIR) extraction yielded three crude polysaccharide fractions (P50, P70, and P90). P50 was obtained with the highest yield (14.31%) and exhibited the highest content of total sugars and uronic acids (68.01 and 24.28 g/100 g, respectively). Calcium, magnesium, and manganese were dominant minerals in P50 and P70. Monosaccharide composition analysis via high-performance liquid chromatography (HPLC) demonstrated enrichment of galacturonic acid, galactose, and arabinose in P50 and P70. Furthermore, both fractions (P50 and P70) exhibited dose-dependent inhibitory effects on α-amylase and α-glucosidase. At 5 mg/mL, P50 caused 68.3% α-amylase inhibition and 62.3% α-glucosidase inhibition, while P70 triggered 46.8% and 34.1% inhibition, respectively. In conclusion, this study is the first to provide valuable insights into optimizing CAL extraction conditions. Potential utilization of polysaccharide fractions obtained from CAL as components for formulating functional foods can be explored in the future.
Źródło:
Polish Journal of Food and Nutrition Sciences; 2024, 74, 2; 177-187
1230-0322
2083-6007
Pojawia się w:
Polish Journal of Food and Nutrition Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioaccumulation of Heavy Metals in Mackerel and Red Hybrid Tilapia Collected From
Autorzy:
Dabwan, Ahmed H. A.
Saluddin, Ummu Asma’ Hafifah Bt. Mohmad
Isa, Nursuhaili Bt. Mohd
Abdullah, Abdul Hadi
Mohamed, Amri Bin Hj.
Ahmad, Anuar Bin
Powiązania:
https://bibliotekanauki.pl/articles/27314829.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
heavy metals
biomonitoring
oreochromis niloticus
Rastrelliger kanagurta
Oreochromis niloticus
metale ciężkie
ekosystem morski
makrela indyjska
tilapia
Opis:
The major goal of this study is to determine the bioaccumulation of heavy metals in the tissues and bones of Red Hybrid Tilapia (Oreochromis niloticus) and Mackerel (Rastrelliger kanagurta) taken from two distinct sites in Terengganu state, Malaysia, namely Kijal and Paka. Zinc (Zn), copper (Cu), nickel (Ni), and lead (Pb)were the metals examined. Soil analysis also was carried out for the same elements. The tissues and bones of the fishes were separated before further analysis was made. Drying process technique was used to determine the moisture content for all samples at 80°C for 24 hours. Water content ranged between 70 & 77%. Triplicate samples were evaluated by using Atomic Absorption Spectrophotometer (AAS) to find out heavy metals concentration. Oven and Teflon beakers were used to fully digest all solid samples at 120oC for 3 hours. Highest readings of Zn, Ni and Pb were found in the fish bone for the samples collected from both mentioned locations. However, different pattern was noticed for Cu where higher values were found in the tissues for the same samples. Values of Pb in the tissues were higher than the acceptable value in edible fish by Food and Agriculture Organization (FAO); 1 ppm and Malaysian Food Act (MFR) & World Health Organization (WHO); 2 ppm, whereas values of Cu, Zn were in the acceptable range set by the same organizations. No values recommended for Ni by MFR. In general heavy metals in the bones and tissues from both locations can be sorted in descending order as follows; Pb>Zn>Cu>Ni. Soil samples collected from both locations showed different pattern where high concentration was found for Zn followed by Pb then Cu and Ni. Moreover analysis for soil samples collected from Paka River showed higher content for all elements compared to Kijal. More investigation is needed to clarify whether this contamination is solely from industry or due to geology of the area.
Źródło:
Civil and Environmental Engineering Reports; 2022, 32, 4; 270--281
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Equilibrium, kinetics and thermodynamic study of the adsorptive removal of methylene blue from industrial wastewater by white cedar sawdust
Autorzy:
Gardazi, Syed Mubashar H.
Shah, Jehanzeb Ali
Ashfaq, Tayyab
Sherazi, Tauqir A.
Ali, Muhammad Arif
Pervez, Arshid
Rashid, Naim
Iqbal, Javed
Amin, Bilal Ahmad Zafar
Bilal, Muhammad
Powiązania:
https://bibliotekanauki.pl/articles/207373.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
methylene blue
industrial wastewater
white cedar sawdust
WCS
dye adsorption
błękit metylenowy
ścieki przemysłowe
trociny białego cedru
adsorpcja barwników
Opis:
The study evaluated the adsorption potential of white cedar sawdust (WCS) for dye removal. WCS was chosen from five preferred, abundant waste biomasses from Pakistan. Various parameters such as contact time, adsorbent dose, dye concentration, pH, and particle size were optimized for methylene blue (MB) dye adsorption. The adsorbent was characterized by FTIR, SEM, EDX and BET analyses. The surface area of the adsorbent was 1.43 m2·g-1 and pore volume was 0.000687 cm3·g-1. The adsorption data best fitted the isotherm models of Langmuir, Temkin, Dubinin–Radushkevich, and Freundlich. The maximum experimental adsorption capacity obtained was 55.15 mg·g-1, which was in close agreement to the calculated adsorption capacity. Fitness of the pseudo-second order kinetics suggested chemisorption as the rate-limiting step. Thermodynamic study for adsorption was carried out to evaluate the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). The negative values ΔG° at the examined temperature range confirmed the spontaneous adsorption of MB onto WCS.
Źródło:
Environment Protection Engineering; 2019, 45, 3; 5-22
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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