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Tytuł:
The impact of Cu alloy on auxiliary and invisible options of splash kept CdS slims
Autorzy:
Kadhim, Mohammed A.
Powiązania:
https://bibliotekanauki.pl/articles/1188099.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CdS
spray pyrolysis
optical properties
Cu concentration
Opis:
Cadmium Sulfide and copper alloyed Cd1-xS Cux slims have been set up by the spray pyrolysis technique. The optical gap crevices at unadulterated and doped Cadmium Sulfide were observed to be shifted from (2.34 to 2.45) eV with increment x from (0 to 0.1). The X-beam diffraction (XRD) investigation uncovered that slims were polycrystalline and showed two phases cubic and hexagonal structure with increasing the hexagonal phase with increment Cu ratio.
Źródło:
World Scientific News; 2016, 56; 217-228
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of human resource practices on the employee commitment and performance
Wpływ praktyk zasobowych na zaangażowanie i wyniki pracowników
Autorzy:
Al Doghan, Mohammed A.
Powiązania:
https://bibliotekanauki.pl/articles/27315182.pdf
Data publikacji:
2022
Wydawca:
Politechnika Częstochowska
Tematy:
HR practices
employee commitment
employee behavior
employee performance
praktyki HR
zaangażowanie pracowników
zachowania pracowników
wydajność pracowników
Opis:
The present study examines the HR practices on the employee commitment, employee behavior and employee performance and also among employee behavior and employee commitment, and employee behavior and employee performance of petroleum industry in Saudi Arabia. This research also investigates the mediating role of employee behavior among the links of HR practices, employee commitment, and employee performance of the petroleum industry in Saudi Arabia. The present article has used questionnaires for data collection and smart-PLS to test the relationships among variables. The results revealed that HR practices have a positive linkage with employee commitment, employee behavior and employee performance, and employee behavior also has a positive association with employee commitment and employee performance of the petroleum industry in Saudi Arabia. The findings also indicated that employee behavior significantly mediates among the relations of HR practices, employee commitment and employee performance of the petroleum industry in Saudi Arabia.
Niniejsze badanie analizuje praktyki HR w zakresie zaangażowania pracowników, zachowań pracowników i wydajności pracowników, a także wśród zachowań i zaangażowania pracowników oraz zachowań pracowników i wydajności pracowników przemysłu naftowego w Arabii Saudyjskiej. Badanie to analizuje również pośredniczącą rolę zachowania pracowników wśród powiązań praktyk HR, zaangażowania pracowników i wydajności pracowników przemysłu naftowego w Arabii Saudyjskiej. W niniejszym artykule wykorzystano kwestionariusze do zbierania danych oraz smart-PLS do testowania relacji między zmiennymi. Wyniki ujawniły, że praktyki HR mają pozytywny związek z zaangażowaniem pracowników, zachowaniem pracowników i wydajnością pracowników, a zachowanie pracowników ma również pozytywny związek z zaangażowaniem pracowników i wynikami pracowników przemysłu naftowego w Arabii Saudyjskiej. Wyniki wskazały również, że zachowanie pracowników istotnie pośredniczy w relacjach praktyk HR, zaangażowania pracowników i wyników pracowników przemysłu naftowego w Arabii Saudyjskiej.
Źródło:
Polish Journal of Management Studies; 2022, 25, 1; 27--40
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of bearing capacity effect in swelling soil
Autorzy:
Mohammed, A. N.
Khalil, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174193.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
grunt nawodniony
nośność gruntu
ciśnienie pęcznienia gruntu
swell pressure
swelling soil
bearing capacity
water content
dry unit weight
Opis:
The current study aims to investigate the effects of swell pressure on the bearing capacity of swelling soil. A model and some laboratory tests have been created to investigate the swell pressure effect on the bearing capacity variation of soil swelling due to swelling pressure. The influence of varying water content [...] and dry unit weight [...] on the shear strength and swelling pressure was studied. The soil has been taken from Diwan Residential Compound-Mosul. It is classified as highly swelling soil. The swell pressure of soils at their natural water content reached [...]. Experiment results show that the parameters of shear resistance decreased with the [...] wcincrease at the constant value of [...], and increased with the [...] increase when the [...] was constant. Results show that the swelling pressure decreased with the wc increase, while it increased with the [...] increase. Also, the results obtained using was model show that the resistance of bearing capacity of pre-saturated selected soil was [...], while the bearing capacity was [...] when taking into account in the generation of swelling pressure.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 4; 167--178
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Existence results of ψ-Hilfer integro-differential equations with fractional order in Banach space
Autorzy:
Almalahi, Mohammed A.
Panchal, Satish K.
Powiązania:
https://bibliotekanauki.pl/articles/1797178.pdf
Data publikacji:
2020-07-20
Wydawca:
Uniwersytet Pedagogiczny im. Komisji Edukacji Narodowej w Krakowie
Tematy:
ψ-Hilfer fractional derivative
Mönch fixed point theorem
Eα-Ulam-Hyers stability
δ-approximate solution
Opis:
In this article we present the existence and uniqueness results for fractional integro-differential equations with ψ-Hilfer fractional derivative. The reasoning is mainly based upon different types of classical fixed point theory such as the Mönch fixed point theorem and the Banach fixed point theorem. Furthermore, we discuss $E_{α}$-Ulam-Hyers stability of the presented problem. Also, we use the generalized Gronwall inequality with singularity to establish continuous dependence and uniqueness of the δ-approximate solution.
Źródło:
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica; 2020, 19; 171-192
2300-133X
Pojawia się w:
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stress–strain relationship of ductile materials and flexural behavior of ductile over-reinforced concrete beams
Autorzy:
Duhaim, Hussein M.
Mashrei, Mohammed A.
Powiązania:
https://bibliotekanauki.pl/articles/36058847.pdf
Data publikacji:
2022
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
ductile material
SFRC
SIFCON
UHPFRC
over-reinforced beam
flexural behavior
ductility
Opis:
This paper aimed to investigate the effect of using ductile materials in the compression zone on the flexural performance of over-reinforced concrete beams. In order to avoid brittle compression failure, partial replacement of concrete with ductile materials layer in the compression zone was used. Four over-reinforced concrete beams of size 120 × 180 × 1,300 mm were cast and tested under three-point loading conditions. The steel fibers reinforced concrete (SFRC), slurry infiltrated fiber concrete (SIFCON), and ultra-high performance fiber reinforced concrete (UHPFRC) were used as ductile materials. The flexural capacity of the beams, failure modes, crack patterns, load-deflection relationships, ductility index, and toughness were investigated. The results showed that using ductile materials in the compression zone is an effective technique to increase the ultimate load, ductility, and toughness by up to 52.46, 84.78 and 279.93%, respectively, compared to the reference beam. In addition, the failure mode changed from brittle to ductile failure. Noting that the use of SFRC layer enhanced the ductility of over-reinforced concrete beams more than using UHPFRC and SIFCON layers. Also, one of the main advantages of this technique is led to increase the tensile reinforcement ratio up to 8.548% without needing the compressive reinforcement. Thus, ductile composite beams with a high flexural capacity were generated using an economical amount of ductile materials.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2022, 31, 4; 225-237
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Challenges and prospects of contraceptives use among women attending family planning services in Yobe State, Nigeria
Autorzy:
Imam, Mohammed A. N. A.
Khan, Bhola
Powiązania:
https://bibliotekanauki.pl/articles/1075579.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Challenges
Contraceptives
Family Planning
Prospects
Services
Opis:
The study focuses on the challenges and prospects of contraceptive use among the women attending family planning services in Potiskam general hospital. The main objective of this study is to identify the major challenges facing the ideal use of the best contraceptive methods among women and to address the available prospects to be adapted in order to contribute for the improvement of family planning services in Yobe State. The population of the to study comprises of one hundred women attending family planning services in Potiskam General Hospital, and Sample size technique adopted using Krejcie and Morgan formula. The structured questionnaire was used to collect data for this study. The data obtained were analyzed by using mean and standard deviation. The findings of the study revealed that the fear of health risk, Lack of consensus among partners, Cultural norms and Religious are considered as the main challenges prevent family planning practice among women mainly the use of contraceptive methods. The findings also revealed that, the use of withdrawal (Coitus Interrupts), the use of Oral Contraceptives (The Pills) method, the use of Female and male Condoms is some of the common methods of family planning devices among women in study area. Finally, the results indicated that, the use of mass media campaign to educate women about family planning devices, use of symbols to display appropriate family planning equipment’s for women and use of guidance and counseling in Primary Health Care to educate women about family planning devices are some of the available prospects and solutions to be adopted for effective promoting family planning services in general and use of contraceptives in particular among women. It is recommended among others that, there is need for government through the Ministry of Health and its partners to revive and support family planning education to both household and community level.
Źródło:
World Scientific News; 2019, 122; 122-132
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficacy of Lepidium Sativum to act as an anti-diabetic agent
Autorzy:
Mishra, N.
Mohammed, A.
Rizvi, S.I.
Powiązania:
https://bibliotekanauki.pl/articles/1918412.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Medyczny w Białymstoku
Tematy:
Lepidium sativum
diabetes
insulin
streptozotocin
oxidative stress
cholesterol
Opis:
Objective: Lepidium sativum, commonly known as chandrashoor in India, has been used in the Indian traditional medicine system for the treatment of various diseases. The present study was undertaken to investigate the hypoglycemic effect of Lepidium sativum in normal and streptozotocin-induced diabetic rats. Materials and methods: Thirty (30) adult male Wistar rats weighing 157±51g were randomly assigned to five groups of six rats each as Normal control, Diabetic control, Diabetics supplemented with Lepidium sativum extract, Diabetics treated with insulin, and Normal rats supplemented with Lepidium sativum. All rats were fed with a normal laboratory diet, nutrient rich pellets, and had free access to drinking water. The rats were injected with streptozotocin at a dose of 45 mg/kg body weight intraperitoneally to induce diabetes. The extracts were then given orally to different groups of rats at a dose of 20mg/kg body weight for 16 days. Thereafter, the rats were sacrificed, and blood samples collected by cardiac puncture were used for the determination of Glucose, Creatinine, Alkaline Phosphatase, Cholesterol, Malondialdehyde level, % DPPH, and FRAP content. Results: Administration of lepidium extract showed a significant reduction in glucose, creatinine, and alkaline phosphatase levels. Elevated cholesterol level was restored approximately to normal; a significant decrease in malondialdehyde levels was also observed compared to diabetic controls. Conclusion: Lepidium sativum extract shows efficacy in the prevention and management of diabetes mellitus and its related complications.
Źródło:
Progress in Health Sciences; 2017, 7(1); 44-53
2083-1617
Pojawia się w:
Progress in Health Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metal Surface Dipole Moment and Work Function in the Linear Potential Model
Autorzy:
Mohammed, A. E.
Ghaly, A. Y.
Frege, O. M.
Powiązania:
https://bibliotekanauki.pl/articles/1891682.pdf
Data publikacji:
1991-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.30.+y
Opis:
Jellium metal surface properties such as the surface dipole barrier and work function are obtained in the linear potential approximation to the effective potential at the surface. The metal surface position and field strength are determined respectively by the requirement of overall charge neutrality and the constraint set on the electrostatic potential by the Budd-Vannimenus theorem. The calculations are primarily analytic and these properties are given in terms of universal functions of the field strength. The results obtained employing the Ceperly-Alder expression for the correlation energy closely approximate those of Lang and Kohn.
Źródło:
Acta Physica Polonica A; 1991, 80, 4; 591-600
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cancer growth treatment using immune linear quadratic regulator based on crow search optimization algorithm
Autorzy:
Hussein, Mohammed A.
Karam, Ekhlas H.
Habeeb, Rokaia S.
Powiązania:
https://bibliotekanauki.pl/articles/1837793.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
oncolytic virotherapy
feedback mechanism
crow search algorithm
Immune-LQR
wiroterapia onkolityczna
mechanizm sprzężenia zwrotnego
algorytm wyszukiwania w tłumie
Opis:
The rapid and uncontrollable cell division that spreads to surrounding tissues medically termed as malignant neoplasm, cancer is one of the most common diseases worldwide. The need for effective cancer treatment arises due to the increase in the number of cases and the anticipation of higher levels in the coming years. Oncolytic virotherapy is a promising technique that has shown encouraging results in several cases. Mathematical models of virotherapy have been widely developed, and one such model is the interaction between tumor cells and oncolytic virus. In this paper an artificially optimized Immune-Linear Quadratic Regulator (LQR) is introduced to improve the outcome of oncolytic virotherapy. The control strategy has been evaluated in silico on number of subjects. The crow search algorithm is used to tune immune and LQR parameters. The study is conducted on two subjects, S1 and S3, with LQR and Immune-LQR. The experimental results reveal a decrease in the number of tumor cells and remain in the treatment area from day ten onwards, this indicates the robustness of treatment strategies that can achieve tumor reduction regardless of the uncertainty in the biological parameters.
Źródło:
Applied Computer Science; 2021, 17, 2; 56-69
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Environmental and Economic Impacts of Municipal Solid Wastes Management System: A Case Study
Autorzy:
Mosbah, Ezzeddine B.
Alsanad, Mohammed A.
Sassine, Youssef N.
Powiązania:
https://bibliotekanauki.pl/articles/2025720.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
environmental impact
economic impact
municipal solid waste management
MSW
life cycle analysis
life cycle cost analysis
Saudi Arabia
LCA&LCCA
Opis:
In pursuance of the Saudi vision 2030, the Al-Hasa municipality has been allocating a total of US$ 60.1 million since 2018 to the implementation of a modern Municipal Solid Wastes (MSW) management system. In addition to the improved old components, the system involves six new-engineered cells, five of which will be gradually implemented in progresses, two waste sort-out lines station, and LFG energy recovery. The present research aimed at investigating the environmental and economic impacts of this MSW management system. For this purpose, the authors applied the Life Cycle Analysis (LCA) and Life Cycle Costs Analysis (LCCA) approaches. The main results showed that the air quality was not affected. For instance, gas emission, like carbon monoxide, was less than 0.1 ppm. However, soil and groundwater were contaminated due to leachate infiltration from the uncontrolled cell in which Chloride, Nitrate, and Sulfate exceeded the maximum limits. As for noise, it was found to be high near the sorting-out station at 71.1 Leq dBA. In terms of the financial aspect, the improved MSW management was relatively feasible despite its high costs over its revenues. Thus, the negative cash-flow could be supplemented by setting household taxes at US$ 29 per capita per year, which makes the project cost-effective. Thus, the research recommends continuing the MSW management project.
Źródło:
Journal of Ecological Engineering; 2022, 23, 1; 137-145
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative study of uni-univalent H⁺/Na⁺ and uni-bivalent H⁺/Ca²⁺ ion exchange reactions using nuclear grade resin Indion-223
Autorzy:
Singare, P. U.
Mohammed, A. L. K.
Dixit, N. N.
Powiązania:
https://bibliotekanauki.pl/articles/411747.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ion exchange reactions
nuclear grade resins
cation exchange resins
enthalpy
equilibrium constant
Indion-223
Opis:
The present paper deals with the ion exchange equilibrium studies of uni-univalent and uni-bivalent ion exchange reactions using nuclear grade anion exchange resin Indion-223 in H⁺ form towards Na⁺ and Ca²⁺ ions in the solution. It was observed that with rise in temperature the equilibrium constants K values for H⁺/Na⁺ uni-univalet ion exchange reaction increases from 0.01389 to 0.01855. Similarly for H⁺/Ca²⁺ uni-bivalet ion exchange reaction the equilibrium constants K values increases from 0.000397 to 0.000639. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 25.55 and 38.92 kJ/ mol respectively.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 14, 2; 127-135
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of uni-univalent H+/K+ and uni-bivalent H+/Mg2+ ion exchange reactions using nuclear grade resin Indion-223
Autorzy:
Singare, P. U.
Mohammed, A. K. L.
Dixit, N. N.
Powiązania:
https://bibliotekanauki.pl/articles/411848.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ion exchange equilibrium
nuclear grade resins
cation exchange
enthalpy change
equilibrium constant
Indion-223
Opis:
In the present paper the uni-univalent and uni-bivalent ion exchange reactions were investigated using nuclear grade anion exchange resin Indion-223 in H+ form. For both H+/K+ uni-univalet ion exchange reactions and H+/Mg2+ uni-bivalet ion exchange reactions, the equilibrium constant K values increases from 0.01710 to 0.02374 and from 0.000177 to 0.000333 respectively as the reaction temperature rises from 35.0 °C to 45.0 °C. The increase in K values with temperature suggest endothermic ion exchange reactions having the enthalpy change values of 22.72 and 51.46 kJ/ mol respectively. The results of such studies will help in selection of suitable ion exchange resins in order to bring about efficient separation of different ionic species present in the waste water effluents released from nuclear as well as chemical process industries.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 14, 2; 231-239
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ion exchange equilibrium studies of uni-univalent H+/Na+ and uni-bivalent H+/Mg2+ ion exchange reactions using nuclear grade resin Indion-223
Autorzy:
Singare, P. U.
Mohammed, A. L. K.
Dixit, N. N.
Powiązania:
https://bibliotekanauki.pl/articles/412153.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
cation exchange
nuclear grade resins
ion exchangers
change in enthalpy
equilibrium constant in standard state
Indion-223
Opis:
In the present investigation the uni-univalent and uni-bivalent ion exchange reactions were studied using nuclear grade anion exchange resin Indion-223 in H+ form. It was observed that for H+/Na+ uni-univalet ion exchange reaction, with rise in temperature the equilibrium constants K values increases from 0.01389 to 0.01855. Similarly increase in K values was observed from 0.000177 to 0.000333 for H+/Mg2+ uni-bivalet ion exchange reaction. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 25.55 and 51.46 kJ/ mol respectively. It is expected that the present study will provide valuable information in order to decide about the selection of those resins for efficient separation of various ionic species present in the industrial waste water effluents.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 14, 2; 199-207
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on preferential selectivity of nuclear grade resin Indion-223 towards some bivalent ions
Autorzy:
Singare, P. U.
Mohammed, A. L. K.
Dixit, N. N.
Powiązania:
https://bibliotekanauki.pl/articles/412085.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
bivalent exchange reactions
nuclear grade resins
cation exchange
reaction thermodynamics
enthalpy change
ionic selectivity
equilibrium constant
Indion-223
Opis:
In the present paper attempts are made to understand the selectivity of nuclear grade cation exchange resin Indion-223 in H+ form towards Ca2+ and Mg2+ bivalent ions in the solution based on thermodynamic concept. It was observed that with rise in temperature the equilibrium constant K values for H+/Ca2+ uni-bivalet ion exchange reactions increases from 0.000397 to 0.000639. Similarly for H+/Mg2+ uni-bivalet ion exchange reactions the equilibrium constant K values increases from 0.000177 to 0.000333. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 38.92 and 51.46 kJ/ mol respectively. The difference in K values and enthalpy values were used to predict the selectivity behaviour of the resin towards the Ca2+ and Mg2+ bivalent ions in the solution. The thermodynamic concept of the present study can be applied to understand the selectivity behaviour of different nuclear as well as non-nuclear grade resins towards wide range of ionic species present in the exchanging liquid medium.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 15; 11-21
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamics of uni-univalent H+/K+ and uni-bivalent H+/Ca2+ ion exchange reactions using nuclear grade resin Indion-223
Autorzy:
Singare, P. U.
Mohammed, A. L. K.
Dixit, N. N.
Powiązania:
https://bibliotekanauki.pl/articles/412388.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ion exchange
nuclear grade resins
cation exchangers
enthalpy change
standard equilibrium constant
Indion-223
Opis:
The present paper deals with the thermodynamic of uni-univalent and uni-bivalent ion exchange reactions using nuclear grade anion exchange resin Indion-223. It was observed that with rise in temperature the equilibrium constants K values for H+/K+ uni-univalet ion exchange reaction increases from 0.01710 to 0.02374. Similarly for H+/Ca2+ uni-bivalet ion exchange reaction the equilibrium constants K values increases from 0.000397 to 0.000639. The increase in K values with rise in temperature for both the reactions indicates its endothermic nature having the enthalpy change values of 22.72 and 38.92 kJ/ mol respectively. The technique used here can be extended further to standardise the process parameters in order to bring about the efficient separation of the desired ionic species from the solution.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 14, 2; 190-198
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic study to evaluate the selectivity behaviour of nuclear grade resin Indion-223 towards some univalent ions
Autorzy:
Singare, P. U.
Mohammed, A. L. K.
Dixit, N. N.
Powiązania:
https://bibliotekanauki.pl/articles/412486.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
uni-univalent ion exchange reactions
ionic selectivity
nuclear grade resins
cation exchangers
enthalpy change
equilibrium constant
Indion-223
Opis:
The present paper deals with the application of thermodynamic concept in understanding the preferential selectivity of nuclear grade anion exchange resin Indion-223 in H+ form towards Na+ and K+ ions in the solution. In the study it was observed that the equilibrium constants K values for H+/Na+ and H+/K+ uni-univalet ion exchange reactions increases from 0.01389 to 0.01855 and from 0.01710 to 0.02374 respectively as the temperature increases from 35.0 °C to 45.0 °C. The increase in K values with rise in temperature suggests endothermic ion exchange reactions having the enthalpy change values of 25.55 and 22.72 kJ/ mol respectively. Based on difference in K values and enthalpy values for the two uni-univalent ion exchange reactions, the preferential selectivity of the resin for the univalent ions in the solution was predicted. From the results of present study, it appears that the experimental technique used here can be applied further to understand the ionic selectivity of different industrial grade ion exchange resins. It is expected that such studies will provide valuable information in order to decide about the selection of those resins for efficient separation of various ionic species present in the industrial waste water effluents.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 15; 22-29
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient analysis of transversely functionally graded Timoshenko beam (TFGTB) in conjunction with finite element method
Autorzy:
Khafaji, Salwan Obaid Waheed
Al-Shujairi, Mohammed A.
Aubad, Mohammed Jawad
Powiązania:
https://bibliotekanauki.pl/articles/140231.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FGM beam
transient response
free vibration
fundamental frequency
finite element method
Timoshenko beam theory
Opis:
In this work, transient and free vibration analyses are illustrated for a functionally graded Timoshenko beam (FGM) using finite element method. The governing equilibrium equations and boundary conditions (B-Cs) are derived according to the principle of Hamilton. The materials constituents of the FG beam that vary smoothly along the thickness of the beam (along beam thickness) are evaluated using the rule of mixture method. Power law index, slenderness ratio, modulus of elasticity ratio, and boundary conditions effect of the cantilever and simply supported beams on the dynamic response of the beam are studied. Moreover, the influence of mass distribution and continuous stiffness of the FGM beam are deeply investigated. Comparisons between the current free vibration results (fundamental frequency) and other available studies are performed to check the formulation of the current mathematical model. Good results have been obtained. A significant effect is noticed in the transient response of both simply supported and cantilever beams at the smaller values of the power index and the modulus elasticity ratio.
Źródło:
Archive of Mechanical Engineering; 2020, LXVII, 3; 299-321
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potential Application of Used Coffee Grounds in Leather Tanning
Autorzy:
Nasr, Ahmed I.
El Shaer, Mohammed A.
Abd-Elraheem, Mohamed A.
Powiązania:
https://bibliotekanauki.pl/articles/24201785.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
leather properties
tannins
vegetable tanning
Opis:
Safety of environment and human health is an essential requirement of modern industrial techniques. Therefore, using natural agents in tanning industry may emerge as a trusted method to avoid the chemical contamination caused by using traditional chromium salts in tanning process. This study aimed to evaluate the hot water extract of used coffee grounds (UCGs) as a vegetable tanning agent. The collected UCGs were dried and extracted with hot water at 90 °C for 2h. The phytochemical screening properties of UCGs extract were determined. Sufficient amount of extract was prepared to be used in leather tanning. Three groups were tanned with UCGs extract solely at concentrations of 20, 30 or 40% of pelts’ weight, while another three groups were tanned with the same concentrations and then re-tanned with 10% of a synthetic tanning agent “Phenol sulfonates”. On tanned leathers, organoleptic, physical and chemical properties were determined; scanning electron micrographs were depicted to examine the leather surface and collagen fiber bundles. Analysis of UCGs extract revealed that it has good tanning properties, as it contained tannins (14.92%), tannins/non tannins ratio (2.06), hide powder (39.57) and Stiasny number (21.16). The results of leather properties showed that using UCGs extract alone at concentration of 40% achieved the best results for the vegetable tanning where the tanned leather had higher (P<0.05) tensile strength, tearing strength and shrinking temperature than that treated with the lower level of 20% UCGs extract. However, 40% of UCGs extract is highly recommended to be used to accomplish the required shrinkage temperature that should be ≥ 70 °C. UCGs extract could be successfully used as tanning agent in vegetable tanning to produce durable leathers with good fullness; it may be used for different manufacturing products, such as footwear and bags. Moreover, using a combination of UCGs extract at any of the used concentrations with phenol sulfonates 10% led to significant improvement in all studied traits as compared with using UCGs extract alone.
Źródło:
Journal of Ecological Engineering; 2023, 24, 3; 10--19
2299-8993
Pojawia się w:
Journal of Ecological Engineering
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:
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:
Maintenance and management of wastewater system components using the condition index system, prediction process and costs estimation
Konserwacja i zarządzanie systemem kanalizacji ściekowej za pomocą systemu wskaźnika stanu, procesu przewidywania i szacowania kosztów
Autorzy:
Amani, N.
Ali, N. M.
Mohammed, A. H.
Samat, R. A.
Powiązania:
https://bibliotekanauki.pl/articles/302164.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
proces zarządzania konserwacją
instalacja
optymalizacja
analiza kosztów
studium przypadku
maintenance management process
component
optimization
cost analysis
case study
Opis:
Component maintenance management of public building is complex and dynamic as the execution of the engineering management system is subjected to sensitive staff and users' requirements and high expectation of the top management for supporting the business. This paper presents the practices and survey need for maintaining the facilities systems in the building. The purpose of this study is maintenance time optimization of building component using the USACERL condition index (CI) system. To achieve this objective, cast iron pipe within wastewater plumbing system is surveyed using the financial analysis for implementation of optimal maintenance time based on limited cost. The findings show how a best time approach to plumbing system maintenance can assist the owner for decision making in component maintenance time based on existing cost.
Zarządzanie konserwacją instalacji budynku publicznego jest złożone i dynamiczne z uwagi na fakt, iż realizacja systemu zarządzania technicznego poddana jest zarówno wymaganiom personelu i użytkowników końcowych jak i oczekiwaniom kierownictwa w zakresie wsparcia rozwoju przedsiębiorstwa. W niniejszym artykule przedstawiono praktykę oraz badania dotyczące potrzeb wiążących się z konserwacją instalacji w budynkach. Celem tego opracowania jest optymalizacja czasu konserwacji tej części budynku za pomocą systemu wskaźnika stanu (condition index - CI) USACERL. Aby osiągnąć ten cel, przeanalizowano za pomocą analizy finansowej system kanalizacji ściekowej oparty na rurach żeliwnych pod kątem przyjęcia optymalnego czasu obsługi w oparciu o ograniczone koszty. Wyniki pokazują jak optymalne podejście czasowe do konserwacji systemu hydraulicznego może pomóc właścicielowi w procesie podejmowania decyzji w aspekcie czasu konserwacji na podstawie rzeczywistych kosztów.
Źródło:
Eksploatacja i Niezawodność; 2013, 15, 2; 161-168
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A complexity efficient PAPR reduction scheme for FBMC-based VLC systems
Autorzy:
Roshdy, Radwa A.
Hussein, Aziza I.
Mabrook, Mohamed M.
Salem, Mohammed A.
Powiązania:
https://bibliotekanauki.pl/articles/2204164.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
filter bank multicarrier
peak-to-average power ratio reduction
computational complexity
cube satellite communication link
inter-satellite communications
Opis:
Visible light communication based on a filter bank multicarrier holds enormous promise for optical wireless communication systems, due to its high-speed and unlicensed spectrum. Moreover, visible light communication techniques greatly impact communication links for small satellites like cube satellites, and pico/nano satellites, in addition to inter-satellite communications between different satellite types in different orbits. However, the transmitted visible signal via the filter bank multicarrier has a high amount of peak-to-average power ratio, which results in severe distortion for a light emitting diode output. In this work, a scheme for enhancing the peak-to-average power ratio reduction amount is proposed. First, an algorithm based on generating two candidates signals with different peak-to- average power ratio is suggested. The signal with the lowest ratio is selected and transmitted. Second, an alternate direct current-biased approach, which is referred to as the addition reversed method, is put forth to transform transmitted signal bipolar values into actual unipolar ones. The performance is assessed through a cumulative distribution function of peak-to-average power ratio, bit error rate, power spectral density, and computational complexity. The simulation results show that, compared to other schemes in literature, the proposed scheme attains a great peak-to-average power ratio reduction and improves the bit the error rate performance with minimum complexity overhead. The proposed approach achieved about 5 dB reduction amount compared to companding technique, 5.5 dB compared to discrete cosine transform precoding, and 8 dB compared to conventional direct current bias of an optical filter bank multicarrier. Thus, the proposed scheme reduces the complexity overhead by 15.7% and 55.55% over discrete cosine transform and companding techniques, respectively.
Źródło:
Opto-Electronics Review; 2023, 31, 1; art. no. e144919
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization and Beneficiation of Clays from Ewekoro for use as Drilling Mud
Autorzy:
Olatunde, Abayomi O.
Olafadehan, Olaosebikan A.
Usman, Mohammed A.
Adeosun, Tunde A.
Powiązania:
https://bibliotekanauki.pl/articles/1193491.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Beneficiation
Bentonite
Chemical analysis
Mineralogical analysis
Montmorillonite
Opis:
The proven bentonite reserve in Nigeria has been modestly estimated at more than 700 million tonnes, however her bentonite does not meet the API regulation standard. Hence this work was done with the aim of characterizing and beneficiating Nigeria bentonite clay to meet the required standard. Bentonite clay was gotten from Ewekoro in Ogun state of Nigeria, it was characterized using X-Ray Diffraction (XRD) to identify the structural layers which indicates the arrangement of the atoms in clay samples and X-Ray Fluorescence Spectrophotometer (XRF) which was used in the quantitative analysis of the elements in the sample. The XRD confirmed the presence of montmorillonite meaning the sample contained bentonite, while the XRF confirmed that the sample is Ca-based rather than the standard Na-based, hence the need for beneficiation. Beneficiation of the bentonite was done by ion exchange with Na2CO3 followed by addition with different compositions of viscosifiers namely: carboxymethyl cellulose (CMC), drispac and guar gum. The rheological properties together with the swelling ratio and filter loss of the clay were determined. Although some of the bentonite compositions met the required standard, but the bentonite formulation with the combination of 20.125 g bentonite + 2.875 g guar gum + 0.6 g drispac gave the best result.
Źródło:
World Scientific News; 2021, 159; 45-58
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 153

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