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Tytuł:
Followership moderation between the relationship of transactional leadership style and employees reactions towards organizational change
Umiar w podążaniu za przywódcą pomiędzy relacjami transakcyjnego stylu przywództwa a reakcjami pracowników w kierunku zmiany organizacyjnej
Autorzy:
Khan, S. N.
Busari, A. H.
Abdullah, S. M.
Mughal, Y. H.
Powiązania:
https://bibliotekanauki.pl/articles/405181.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska
Tematy:
transactional leadership style
followership
employees’ reactions
organizational change
Pakistan
transakcyjny styl przywództwa
podążanie za przywódcą
reakcje pracowników
zmiana organizacyjna
Opis:
The purpose of the present study is to analyze the relationship between transactional leadership style and factors of employees’ reactions towards organizational change in the telecommunication companies of Pakistan. Furthermore, to understand the importance of followership this study has also incorporated followership as a moderating variable. Quantitative methodology is applied to investigate the underline relationships. The Pearson correlation results have identified that transactional leadership is positively related to all three factors (frequency of change, trust in management, and employees’ participation) of employees’ reactions towards change. The moderation results further clarify that followership significantly moderates the relationship between transactional leadership style, frequency of change and employees participation. However, there is no moderation effect found between transactional leadership style and trust in management.
Celem niniejszego badania jest analiza związku między stylem przywództwa transakcyjnego a czynnikami reakcji pracowników na zmiany organizacyjne w przedsiębiorstwach telekomunikacyjnych w Pakistanie. Ponadto, aby zrozumieć znaczenie podążania za przywódcą, zostało ono włączone jako zmienna moderująca. W celu zbadania istniejących zależności, zastosowana została metodologia ilościowa. Wyniki korelacji Pearsona wykazały, że przywództwo transakcyjne jest pozytywnie powiązane ze wszystkimi trzema czynnikami (częstością zmian, zaufaniem do zarządzania i udziałem pracowników) reakcji pracowników na zmiany. Uzyskane wyniki pozwoliły stwierdzić, że wyniki moderacji dodatkowo wyjaśniły, że podążanie za przywódcą znacząco moderowało związek pomiędzy stylem przywództwa transakcyjnego, częstotliwością zmian a udziałem pracowników. Jednak nie znaleziono efektu powiązania pomiędzy stylem przywództwa transakcyjnego a zaufaniem do zarządzania.
Źródło:
Polish Journal of Management Studies; 2018, 17, 1; 131-143
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Classification of EEG Signals Using Adaptive Time-Frequency Distributions
Autorzy:
Khan, N. A.
Ali, S.
Powiązania:
https://bibliotekanauki.pl/articles/221878.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Adaptive Directional Time-Frequency Distribution
EEG signals
Time-Frequency features
pattern recognition
Opis:
Time-Frequency (t-f) distributions are frequently employed for analysis of new-born EEG signals because of their non-stationary characteristics. Most of the existing time-frequency distributions fail to concentrate energy for a multicomponent signal having multiple directions of energy distribution in the t-f domain. In order to analyse such signals, we propose an Adaptive Directional Time-Frequency Distribution (ADTFD). The ADTFD outperforms other adaptive kernel and fixed kernel TFDs in terms of its ability to achieve high resolution for EEG seizure signals. It is also shown that the ADTFD can be used to define new time-frequency features that can lead to better classification of EEG signals, e.g. the use of the ADTFD leads to 97.5% total accuracy, which is by 2% more than the results achieved by the other methods.
Źródło:
Metrology and Measurement Systems; 2016, 23, 2; 251-260
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unsteady hydromagnetic flow of Oldroyd-B fluid over an oscillatory stretching surface: a mathematical model
Autorzy:
Khan, S. U.
Ali, N.
Powiązania:
https://bibliotekanauki.pl/articles/297856.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
Oldroyd-B fluid
oscillatory stretching sheet
homotopy analysis method
Opis:
In the present work, we have studied an unsteady, two-dimensional boundary layer flow of a magnetohydrodynamics (MHD) Oldroyd-B fluid over an oscillatory stretching surface. The problem is modeled by using constitutive equations. The number of independent variables in the governing equations are reduced by using appropriate dimensionless variables. The analytical solution is computed by using homotopy analysis method. The influences of various physical parameters such as Deborah numbers, ratio of angular frequency to stretching rate parameter and Hartmann number on time-series of velocity and transverse velocity profiles at different time instants are investigated and discussed quantitatively with the help of various graphs. It is observed that amplitude of velocity increases by increasing ratio of oscillating frequency to stretching rate parameter while decreases by increasing Hartmann number. It is further observed that the magnitude of velocity decreases by increasing Hartmann number and Deborah numbers in the terms of relaxation time parameter.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2017, 20(1); 87-100
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Entropy generation on mhd flow of Powell-Eyring fluid between radially stretching rotating disk with diffusion-thermo and thermo-diffusion effects
Autorzy:
Khan, N. A.
Aziz, S.
Ullah, S.
Powiązania:
https://bibliotekanauki.pl/articles/386796.pdf
Data publikacji:
2017
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
axisymmetric flow
entropy generation
stretching disk
Powell-Eyring fluid
diffusion
Opis:
An investigation is performed for an alyzing the effect of entropy generation on the steady, laminar, axisymmetric flow of an incompressible Powell-Eyring fluid. The flow is considered in the presence of vertically applied magnetic field between radially stretching rotating disks. The Energy and concentration equation is taking into account to investigate the heat dissipation, Soret, Dufour and Joule heating effects. To describe the considered flow non-dimensionalized equations, an exact similarity function is used to reduce a set of the partial differential equation into a system of non-linear coupled ordinary differential equation with the associated boundary conditions. Using homotopy analysis method (HAM), an analytic solution for velocity, temperature and concentration profiles are obtained over the entire range of the imperative parameters. The velocity components, concentration and temperature field are used to determine the entropy generation. Plots illustrate important results on the effect of physical flow parameters. Results obtained by means of HAM are then compared with the results obtained by using optimized homotopy analysis method (OHAM). They are in very good agreement.
Źródło:
Acta Mechanica et Automatica; 2017, 11, 1; 20-32
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel approach to enhance performance of multilayer coated carbide insert in hard turning
Nowe podejście do poprawy osiągów w toczeniu na twardo przy użyciu wielowarstwowej płytki z ceramiki narzędziowej
Autorzy:
Shihab, S. K.
Khan, Z. A.
Siddiquee, A. N.
Khan, N. Z.
Powiązania:
https://bibliotekanauki.pl/articles/140027.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hard turning
flank wear
Taguchi approach
multi-coated carbide
micro-channel
toczenie na twardo
zużycie krawędzi
podejście Taguchi
węglik wielowarstwowy
mikrokanał
Opis:
Flank wear of multilayer coated carbide (TiN/TiCN/Al2O3/TiN) insert in dry hard turning is studied. Machining under wet condition is also performed and flank wear is measured. A novel micro-channel is devised in the insert to deliver the cutting fluid directly at the tool-chip interface. Lower levels of cutting parameters yield the minimum flank wear which is significantly affected by cutting speed and feed rate. In comparison to dry and wet machining, insert with micro-channel reduces the flank wear by 48.87% and 3.04% respectively. The tool with micro-channel provides saving of about 87.5% in the consumption of volume of cutting fluid and energy.
W pracy przedstawiono badania nad zużyciem krawędzi skrawającej wielowarstwowej płytki z ceramiki narzędziowej (TiN/TiCN/Al2O3/TiN) w toczeniu twardym na sucho. Badano także zużycie krawędzi skrawającej w warunkach toczenia na mokro. Nowatorskim rozwiązaniem było zastosowanie mikrokanału w płytce skrawającej, przez który płyn smarny dostarczany jest bezpośrednio do styku między narzędziem i wiórem. Uzyskany tą drogą niższy poziom parametrów skrawania zapewnia minimalne zużycie krawędzi skrawającej, na które w istotny sposób wpływają prędkość skrawania i szybkość posuwu. W porównaniu do warunków toczenia na sucho i na mokro, zastosowanie mikrokanału zmniejsza zużycie krawędzi skrawającej o odpowiednio 48,87% i 3,04%. Narzędzie z mikrokanałem zapewnia także oszczędność zużycia płynu smarnego i energii o ok. 87,5%.
Źródło:
Archive of Mechanical Engineering; 2015, LXII, 4; 539-552
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of chilling exposure and vapor heat treatment duration on the quality of sweet orange during simulated marketing
Autorzy:
Hussain, I.
Rab, A.
Khan, N.U.
Sajid, M.
Ali, N.
Khan, S.M.
Ali, S.
Powiązania:
https://bibliotekanauki.pl/articles/11543553.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Opis:
Sweet orange fruits were exposed to vapor heat treatment (50°C) in water bath for 0, 5, 10, 15 and 20 min in plastic covered structure. The data were recorded on different physico chemical factors immediately after the storage and after seven days simulated marketing under ambient condition (20°C). Low temperature storage enhanced weight loss, surface pitting, disease incidence, total soluble solids accumulation, TSS/Acid ratio but decreased reducing sugars, acidity and ascorbic acid content. Chilling exposure up to 45 days had no significant effect on weight loss and TSS. However, increased weight loss (2.63%), TSS (11.75), TSS/Acid ratio (8.45 ºBrix), disease incidence (8.93%) and lowest reducing sugars (3.90) were noted in sweet orange exposed to chilling temperature for 75 days. Among the VHT durations, the highest weight loss (2.29%) was found in VHT for 0 min while the highest TSS (11.81 ºBrix), TSS/Acid ratio (8.10) and disease incidence (6.22%) and least reducing sugars (4.12%) were found in VHT 20 for min. Vapor heat treatment ranging from 5–10 min resulted in lowest weight loss (1.79%), TSS (10.81 ºBrix) TSS/Acid ratio (7.33), disease incidence (1.00%) and highest reducing sugars (4.75%) in sweet orange fruits. However, non-reducing sugars were least affected by both LTSs and VHTs. It is concluded that the chilling exposure (5°C) beyond 45 days aggravated the decline of fruit physio-chemical quality characteristics. Whereas, VHT with 5–10 min maintained the sweet orange fruit quality during simulated marketing; however, VHT of 15–20 min adversely affected the sweet orange fruit quality attributes.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2017, 16, 5; 39-47
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heterosis for yield and yield components in diallel crosses of Brassica napus L.
Heterozja dla plonu i jego składników w krzyżowaniu diallelicznym rzepaku (Brassica napus L.)
Autorzy:
Farhatullah, F.
Khan, N.A.
Abbas, S.J.
Powiązania:
https://bibliotekanauki.pl/articles/832735.pdf
Data publikacji:
2006
Wydawca:
Instytut Hodowli i Aklimatyzacji Roślin
Tematy:
heterosis
yield
yield component
diallel cross
Brassica napus
hybrid
F1 hybrid
rapeseed
Pakistan
breeding programme
plant breeding
Źródło:
Rośliny Oleiste - Oilseed Crops; 2006, 27, 1
1233-8273
Pojawia się w:
Rośliny Oleiste - Oilseed Crops
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of nutrient media and phytohormones on in vitro establishment of Bambusa balcooa Roxb.
Autorzy:
Khan, H.R.
Burla, S.
Siri, N.
Lavanya, P.
Powiązania:
https://bibliotekanauki.pl/articles/11261.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
nutrient
phytohormone
in vitro
establishment
Bambusa balcooa
bamboo
plant growth regulator
Opis:
Bambusa balcooa.Roxb. is one of the most commercially important bamboo species. Some varieties of bamboo are being grown in the company’s green house. However this species is very rare and it was not cultured until now due to lack of demand and maintenance problems. In this work B. balcooa ex-plants have been established and propagated by the axillary shoot bud proliferation method. Earlier several works have been done on this plant and a protocol has been. This work emphasizes on effects of phytohormones at different concentrations and combinations upon the novel propagules that develop from the bamboo explants on placing them in multiplication media. The propagules placed in media containing cytokinins BAP (2 mg/L) and Kinetin (1 mg/L) exhibited best results of linear as well as radial growth. The other propagules in media with combinations of BAP, Kinetin and NAA were found to be dried out and did not depict noticeable growth. Comparatively next best growth pattern to the former was observed in control media that lacked phytohormones. This experiment was helpful in estimating the quantity and effect of particular plant growth regulating hormones on the Bambusa balcooa.Roxb.
Źródło:
International Letters of Natural Sciences; 2014, 12, 1
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Developed jet-centrifugal spray devices: experimental testing to establish the possibility of their application in plants spraying technologies
Autorzy:
Vambol, S.
Khan, N. A.
Khan, A. H.
Kiriyenko, M.
Borysova, L.
Taraduda, D.
Zakora, A.
Bilotserkivska, N.
Powiązania:
https://bibliotekanauki.pl/articles/1818826.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
jet-centrifugal spray device
experimental testing
operational characteristics
plants spraying
urządzenie natryskowe
badania eksperymentalne
właściwości eksploatacyjne
opryskiwanie roślin
Opis:
Purpose: Experimentally substantiate the possibility of using the developed jet-centrifugal spraying device in plants spraying technologies. Design/methodology/approach: Many years of experience in creating spraying devices for solving practical problems in various industries made it possible to propose a design diagram of a single-phase jet-centrifugal spraying device. The tests were aimed at achieving device characteristics that are acceptable for use in plants spraying technologies such as jet coverage distance, droplet size and droplet deposition area (spray diameter). For this a several tests series with different design parameters was done. Before testing, the tightness of the device body was checked (the holding time under a pressure of 1 MPa is not less than 2 minutes). Findings: Based on the obtained jet coverage distance, droplet size and droplet deposition area, the developed spray device of some modifications can be used in plants spraying technologies. However, it is necessary to determine the quality of the spray device according to the BCPC classification; the device should be tested with some insecticides, fungicides and in plants spraying technologies to develop recommendations for their use. Research limitations/implications: The influence of design features of developed jetcentrifugal spray device on the jet coverage distance, droplet size and droplet deposition area was studied. Practical implications: The results obtained are useful in the field of improving national plants spraying technologies in order to improve the quality of the plant protection agent application and reduce the loss of the drug into the environment. Originality/value: To ensure maximum efficiency the proposed design of the jetcentrifugal spray device can be upgraded directly by the farmer by installing interchangeable nozzles that are attached with a union nut. Replaceable nozzles have different diameters and modifications and can be selected depending on the required jet coverage distance and spraying dispersion according to the current environmental conditions.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2020, 102, 1; 30--41
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Transition in Quasi-Two-Dimensional Horizontally Driven Granular System
Autorzy:
Shah, S.
Li, Y.
Khan, W.
Din, N.
Chand, R.
Powiązania:
https://bibliotekanauki.pl/articles/1489921.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Rm
64.60.-i
Opis:
In an experimental setup, consisting of quasi-two-dimensional square cell, the motion of monodisperse spherical steel balls is studied. The cell is vibrated horizontally to eradicate the compaction of balls due to gravity. By raising the number density of the steel balls, the dilute fluid has been gradually alternated into dense fluid. The temperature of granular media, along the driven and transverse directions, has been found to be anisotropic. Transition from granular gas to the liquid-like fluid has been observed. The radial distribution function of the balls in the cell is investigated for the authentication of the structural changes. Furthermore, the fast Fourier transformation for the 2D system is carried out to confirm these changes.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 699-702
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Genetic diversity of Brassica rapa germplasm of Khyber Pakhtunkhwa Pakistan revealed by molecular markers
Autorzy:
Ali, N.
Ali, S.
Khan, N.U.
Jan, S.A.
Rabbani, M.A.
Hussain, I.
Powiązania:
https://bibliotekanauki.pl/articles/12690092.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
Pakistan
plant breeding
Brassica rapa
germplasm
genetic diversity
plant genotype
molecular marker
SSR marker
Opis:
A total of 96 indigenous Brassica rapa accessions were collected from different locations of Khyber Pakhtunkhwa, Pakistan. Simple Sequence Repeats (SSR) markers were used to identify the most diverse genotypes among the collected lots. Twenty six (26) different SSR primers were used for (genetic) variability among collected genotypes. These primers were selected from literature based on their previous results. These primers produced 135 scorable bands of which 75 were polymorphic, with an average of 55.5% polymorphic loci, and reflected the broader genetic background of the collected genotypes. An average 2.88 polymorphic bands with an average PIC value of 0.49 was recorded. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) divided all genotypes into three main groups. Group one contained three clusters, while group two and three had four and two clusters each. Based on the UPGMA dendrogram, genotypes collected from Kohat, Bannu, Swat and Haripur showed considerable amount of variation. From the present study, it is concluded that SSR markers can be proved as the best tool for the genetic variability of other local and exotic B. rapa genotypes.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2019, 18, 6; 57-65
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytochemical and pharmacological aspects of Nothapodytes nimmoniana. An overview
Profil fitochemiczny i farmakologiczny Nothapodytes nimmoniana. Przegląd
Autorzy:
Khan, N.
Tamboli, E.T.
Sharma, V.K.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/72676.pdf
Data publikacji:
2013
Wydawca:
Instytut Włókien Naturalnych i Roślin Zielarskich
Tematy:
phytochemistry
pharmacology
Nothapodytes nimmoniana
Icacinaceae
camptothecin
medicinal property
human disease
treatment
Opis:
Nothapodytes nimmoniana (J. Graham) (Icacinaceae), commonly known as Amruta is found in India particularly in Maharashtra, Goa, Kerala, Assam, Jammu and Kashmir as well as Tamilnadu areas. It is an important medicinal plant, the major source of a potent alkaloid, namely camptothecin, of a wide spectrum of pharmacological activities like anti-cancer, anti-HIV, antimalarial, antibacterial, anti-oxidant, anti-inflammatory, anti-fungal and also applied in the treatment of anaemia. Camptothecin is still not synthesized, therefore, its production entirely depends on natural sources. N. nimmoniana is one such plant which yields contain camptothecin in significantly high amount. The plant is gaining international recognition due to its diversified medicinal uses. It is subjected to excessive harvest. It has been categorized as a vulnerable and endangered plant. The present review encompasses the phytochemical, analytical, pharmacological, biotechnological, and other specific aspects of N. nimmoniana.
Nothapodytes nimmoniana (J. Graham) (Icacinaceae), powszechnie znana jako Amruta, rośnie w Indiach, szczególnie w prowincjach Maharashtra, Goa, Kerala, Assam, Dżammu i Kaszmir, a także na niektórych obszarach Tamilnadu. Jest jedną z ważnych roślin leczniczych, głównym źródłem silnego alkaloidu, kamptotecyny, mającej szerokie spektrum działania: przeciwnowotworowe, anty-HIV, antymalaryczne, antybakteryjne, przeciwutleniające, przeciwzapalne, przeciwgrzybicze. Znajduje również zastosowanie w leczeniu anemii. Jak dotąd kamptotecyna nie została zsyntetyzowana, dlatego jej produkcja całkowicie zależy od źródeł naturalnych. N. nimmoniana jest jedną z roślin zawierających duże ilości kamptotecyny. Zyskała ona międzynarodowe uznanie dzięki szerokiemu spektrum zastosowań, co powoduje zwiększenie jej eksploatacji. Z tego powodu została uznana za gatunek zagrożony. Poniższy przegląd obejmuje badania fitochemiczne, analityczne, farmakologiczne, biotechnologiczne i inne prowadzone nad gatunkiem N. nimmoniana.
Źródło:
Herba Polonica; 2013, 59, 1
0018-0599
Pojawia się w:
Herba Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of flux composition on the percentage elongation and tensile strength of welds in submerged arc welding
Efekt składu topnika na wydłużenie procentowe i wytrzymałość na rozciąganie spawów przy spawaniu łukiem krytym
Autorzy:
Singh, B.
Khan, Z. A.
Siddiquee, A. N.
Maheswari, S.
Sharma, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/140322.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultimate tensile strength
carbon equivalent
basicity index
elements transfer
delta quantity
UTS
wytrzymałość na rozciąganie
równoważnik węglowy
współczynnik zasadowości
transfer pierwiastków
wielkość delta
Opis:
This experimental study reveals the effects of CaF2, FeMn and NiO additions to the base fluxes on tensile strength and percentage elongation of the weld metal. The aim of this study is to develop suitable flux for mild steel for high tensile strength, impact strength and ductility. Bead on plate welds were made using submerged arc welding process. Mathematical model for percentage elongation and UTS of mild steel welds were made. The elements transfer to the welds have been correlated with the above mechanical performance characteristics. The effect of oxygen content on weld elongation and UTS also has been deduced. This study shows that CaF2 and NiO are the significant factors for tensile strength while FeMn is not significant for tensile strength. However, for elongation besides CaF2, the interaction of CaF2 and FeMn was also found significant. The effects of basicity index of the flux and carbon equivalent of the welds on tensile strength and percentage elongation of the welds have also been evaluated.
W studium eksperymentalnym, przedstawionym w pracy, pokazano wpływ domieszek CaF2, FeMn i NiO do podstawowego składu topnika na wytrzymałość na rozciąganie i procentowe wydłużenie metalu spawu. Celem studium było opracowanie topnika odpowiedniego dla stali niskowęglowej, który zapewnia wysoką wytrzymałość na rozciąganie, wytrzymałość na udary i plastyczność. Ściegi spawów wykonano metodą spawania łukiem krytym. Opracowano model matematyczny wydłużenia procentowego i wytrzymałości na rozciąganie (UTS) dla spawów ze stali niskowęglowej. Zbadano korelację między wymienionymi charakterystykami mechanicznymi a transferem pierwiastków do spawu. Wyznaczono także wpływ zawartości tlenu na wydłużenie spawu i ostateczną wytrzymałość na rozciąganie. W badaniach doświadczalnych wykazano, że domieszki CaF2 oraz NiO są istotnymi czynnikami wpływającymi na wytrzymałość na rozciąganie, podczas gdy domieszka FeMn nie ma istotnego wpływu. Oceniono także wpływ współczynnika zasadowości topnika i równoważnika węglowego spawu na wydłużenie procentowe spawu.
Źródło:
Archive of Mechanical Engineering; 2016, LXIII, 3; 337-354
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pollution and health risk assessment of water quality: a case study in Mohammedia prefecture in Morocco
Autorzy:
El morabet, R.
Berhazi, L.
Khan, R. A.
Bouhafa, S.
Khan, N. A.
Hakh, T.
Romaniv, A.
Powiązania:
https://bibliotekanauki.pl/articles/2055750.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
water quality assessment
water pollution index
ecological risk
non-carcinogenic risk
carcinogenic risk
ocena jakości wody
wskaźnik zanieczyszczenia wody
ryzyko ekologiczne
ryzyko nierakotwórcze
ryzyko rakotwórcze
Opis:
Purpose: Water is vital for the sustenance of every life form. Urbanization, growing population and industrial development has led to exploitation of water resources globally. This study assesses quality of water resources of Mohammedia prefecture. Design/methodology/approach: The water quality analysis was carried out based on physio-chemical and heavy metal concentrations. The physio-chemical analysis comprised of status of concentration, overall quality and water pollution index evaluation. The heavy metal evaluation consisted of Ecological Risk Index, non-carcinogenic risk and carcinogenic risk assessment. Findings: The landfill near Ben Nfifikh River reported insignificant (WPI<1) – low level of pollution (>1≤1.5) for surface and groundwater points. However, the groundwater for Zenata region was found to pose both carcinogenic (CRt > 0.0001, range 0.4-35.31) and non-carcinogenic risks (HQ>1, range 6 -34) of higher degree rendering it unfit for human consumption. Hence, this study concludes that groundwater resources should not as water supply; instead, Oud El Maleh River can serve as surface water source for meeting requirements of Zenata region. Research limitations/implications: The data obtained can be categorized as landfill area near river Nfifikh and landfill area near river El Maleh. Both areas have been investigated for groundwater and surface water quality assessment. Practical implications: This study demonstrates the need to study the characteristics of groundwater (depth, flow rate, water renewal, etc.) before arranging a waste dump. This problem is especially relevant for arid countries, since residents experience a shortage of water, as well as a lack of rainfall provides a weak renewal of groundwater, which can contribute to the accumulation of a higher concentration of carcinogens in groundwater and provide a high risk to public health. If policymakers in arid countries and decision-makers have effective water quality maps, then the country can be more efficiently managed water resources without risking the population. Originality/value: The current study is planned as a multi-stage, each of which is supposed to conduct field studies of groundwater and surface water quality with appropriate parameters, analysis of institutional reports and related scientific studies in order to create an effective water quality map for rational water use.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 110, 2; 67--85
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical Estimation and Mathematical Modelling of Tropospheric Radio Refractivity Based on Meteorological Data
Autorzy:
Alimgeer, K. S.
Awais, M.
Ijaz, B.
Khan, S. A.
Subhan, F.
Ahmad, N.
Powiązania:
https://bibliotekanauki.pl/articles/221069.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radio refractivity
statistical estimation
ITU
mathematical modelling
Opis:
To obtain optimal performance, estimation of radio refractivity is essential in planning and design of radio links/systems. The dependence of radio refractivity on different climatic parameters such as temperature, pressure, humidity and scale height is studied. The method proposed by International Telecommunication Union (ITU) is used in calculation of tropospheric radio refractivity. The main objective of this work is to formulate a mathematical equation/expression which can be used to predict/estimate the value of radio refractivity for an arbitrary day of any year, with a low error of estimation, in a local environment. Sensitivity of radio refractivity to temperature, pressure and humidity has been evaluated for a period of 5 years from 2008 to 2012, in a particular area under consideration. The results presented for tropospheric radio refractivity take into consideration both the location height and scale height parameters. The results are analysed in terms of statistical measures such as the moving averages, probability density function, monthly mean values, and their corresponding standard deviations. Finally, a mathematical model is formulated to calculate the radio refractivity for any day of a whole year. Reliability of error analysis in respect to accuracy is also shown. It was implemented in the industrial enterprise.
Źródło:
Metrology and Measurement Systems; 2018, 25, 1; 115-128
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 22

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