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Wyszukujesz frazę "Mahmood, A." wg kryterium: Autor


Tytuł:
Task allocation algorithms for maximizing reliability of heterogeneous distributed computing systems
Autorzy:
Mahmood, A.
Powiązania:
https://bibliotekanauki.pl/articles/205582.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
heurystyka
niezawodność
obliczenie zdecentralizowane
przetwarzanie rozproszone
A* algorithm
branch-and-bound
distributed computing
heuristics
reliability
task allocation
Opis:
The rapid progress of microprocessor and communication technologies has made the distributed computing system economically attractive for many computer applications. One of the first problems encountered in the operation of a distributed system is the problem of allocating the tasks among the processing nodes. The task allocation problem is known to be computationally intractable for large task sets. In this paper, we consider the task allocation problem with the goal of maximizing reliability of heterogeneous distributed systems. After presenting a quantitative task allocation model, we present a least-cost branch-and-bound algorithm to find optimal task allocations. We also present two heuristic algorithms to obtain suboptimal allocations for realistic size large problems in a reasonable amount of computational time. Simulation was used to study the performance of the proposed algorithms for a large number of problems. Also, performance of the proposed algorithms has been compared with a well-known heuristics available in the literature.
Źródło:
Control and Cybernetics; 2001, 30, 1; 115-130
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling and Simulation of a Photovoltaic Module in Different Operating Regimes
Autorzy:
Jadallah, A.
Mahmood, D.
Abdulqader, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1402513.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.40.+w
77.80.-e
Opis:
Modern research focuses on the renewable energy sources such as solar energy. This paper presents the modeling and performance of a photovoltaic (PV) cell. A simulation code is built using MATLAB. Results show that the increase of solar radiation and of ideality factor of diode lead to an increase in the output power of PV module, while the increease of cell temperature and of the dark saturation current lead to a decrease of the power. Curves of I-V and P-V dependencies are presented for module having 50 branches connected in parallel, with each branch having 50 cells connected in series. Data for certain Iraqi governorates are taken and applied for proposed module.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-461-B-464
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Study of Some Electrical Properties of PVA-Ni(NO3)2 Composites
Autorzy:
Salman, S.A.
Bakr, N. A.
Mahmood, M.H.
Powiązania:
https://bibliotekanauki.pl/articles/411873.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
polyvinyl alcohol
Casting method
Electrical properties
Composites
Opis:
The aim of this paper is to prepare and study the (D.C.) electrical conductivity of (PVA-Ni(NO₃)₂) composites at different temperatures. For that purpose, PVA films with Ni(NO₃)₂ salt additive were prepared with different concentrations 2, 4, 6, 8 and 10 wt. % and with thickness of 45μm by using casting technique. The experimental results for PVA-Ni(NO₃)₂) films show that the (D.C.) electrical conductivity increased with increasing the filler content and the temperature, and the activation energy was decreased with increasing the filler content.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2015, 40; 36-42
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybridization of solar/wind energy system for power generation in rural aeras
Autorzy:
Jadallah, A.
Mahmood, D.
Er, Z.
Abdulqaedr, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1068565.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.20.Bb
89.30.Cc
Opis:
This work is devoted to modeling, analysis and simulation of a small-scale stand-alone wind/PV hybrid power generation system. Wind turbine is modelled and many parameters are taken into account, such as pitch angle, rotor diameter, wind speed, etc. The PV module is then modelled under nominal conditions such as cell temperature, solar radiation, etc. A MATLAB computer programs is developed to solve the mathematical model for small scale horizontal axis wind turbine and PV system. The experimental study has been conducted using a small scale wind turbine based on 500 W permanent magnet synchronous generator. A PV panel used has 36 monocrystalline silicon cells connected together in series having the ability to generate 50 W of rated power. Results show that the load consumes power from both systems but there is an excess and lack of power supply in some operating conditions, such as variation of solar radiation and wind speed.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 434-437
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of Natural radioactivity in tap water samples for selected regions in Thi-Qar Governorate - Iraq
Autorzy:
Hadi, Hasan A.
Karim, Mahmood S.
Mahi, Ali T.
Abood, Tareq H.
Powiązania:
https://bibliotekanauki.pl/articles/1192660.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
(HPGe) detector
Thi-Qar governorate
tap water
specific activity
radionuclides
Opis:
In the present work, we have measured specific activity concentrations in ten tap water samples for selected regions in Thi-Qar governorate by using high purity germanium (HPGe) detector. The results have shown that, the specific activity, for 238U was ranged from (0.65±0.8 Bq/kg) in AL- Nasir region to (1.32±0.7.8 Bq/kg) in AL-Refai region, for 232Th the specific activity was ranged from (0.120±0.34 Bq/kg) in AL-Garraf region to (0.980±0.99 Bq/kg) in AL- Dwaya region, for 40K the specific activity was ranged from (13.33±3.6 Bq/kg) in AL-Nasir region to (38.54±6.2 Bq/kg) in (AL-Garraf) region, with an average values of (0.933±0.16 Bq/kg), (0.737±0.17 Bq/kg), (24.451±7.5Bq/kg), for 238U, 232Th and 40K, respectively. In order to asses the radiological hazards of the radioactivity in tap water, we have been calculated the parameters (Raeq , DƔ, AEDin , AEDout , EAD , Iɣ , Hin and Hex).
Źródło:
World Scientific News; 2016, 47, 2; 112-122
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatiotemporal monitoring of CO2 and CH4 over Pakistan using Atmospheric Infrared Sounder (AIRS)
Autorzy:
Mahmood, I.
Iqbal, M.F.
Shahzad, M.I.
Waqas, A.
Atique, L.
Powiązania:
https://bibliotekanauki.pl/articles/11805.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Carbon dioxide (CO2), Methane (CH4) are two most potent greenhouse gases and are major source of climate change. Human activities particularly fossil fuels burning have caused considerable increase in atmospheric concentrations of greenhouse gases. CO2 contributes 60% of anthropogenic greenhouse effect whereas CH4 contributes 15%. Ice core records also show that the concentrations of Carbon dioxide and methane have increased substantially. The emission of these gases alters the Earth’s energy budget and are drivers of climate change. In the present study, atmospheric concentration of CO2 and CH4 over Pakistan is measured using Atmospheric Infrared Sounder (AIRS). Time series and time averaged maps are prepared to measure the concentrations of CO2 and CH4. The results show considerable increase in concentration of Carbon dioxide and methane. The substantial increase in these concentrations can affect human health, earth radiative balance and can damage crops.
Źródło:
International Letters of Natural Sciences; 2016, 58
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of micronutrients (Cu, Zn, Mn, and Fe) on the growth of Spathoglottis plicata plantlets
Autorzy:
Yasin, Z.A.M.
Mahmood, M.
Shaharudiin, N.A.
Powiązania:
https://bibliotekanauki.pl/articles/79811.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2017, 98, 1
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and Theoretical Investigation to Study the Molecular Structure, Electronic Properties, UV–Vis Spectra of Coumarin 102
Autorzy:
Mohi, Ali T.
Abood, Tareq H.
Hadi, Hasan A.
Karim, Mahmood S.
Mutlik, Falah A-H.
Alwan, Tariq J.
Powiązania:
https://bibliotekanauki.pl/articles/1178533.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
DFT
Ionization potential
TDDFT
electron affinity
energy gap and UV spectra
Opis:
In this work, we study the structure, electronic properties and electronic spectra of Coumarin 102 (C102) dissolved in ethanol as an experimental-theoretical investigation. The various properties of the ground and excited electronic states of coumarins 102 using density functional theory (DFT) and time-dependent density functional theory (TDDFT) was calculated by the B3LYP density functional model with 6-31G(d,p) basis set by Gaussian 09 W program. Spectral characteristics of coumarin 102 have been probed into by methods of experimental UV-visible, and quantum chemistry. The UV spectrum was measured in Ethanol. The optimized structures, total energies, electronic states (HOMO- LUMO), energy gap, ionization potentials, electron affinities, chemical potential, global hardness, softness, global electrophilictity, dipole moment and electrostatic potential was calculated. were calculated. We find good agreement between experimental data of UV spectrum and TDDFT excitation energies.
Źródło:
World Scientific News; 2017, 70, 2; 216-229
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of the etching time and current density on Capacitance-Voltage characteristics of P-type of porous silicon
Autorzy:
Hadi, Hasan A.
Abood, Tareq H.
Mohi, Ali T.
Karim, Mahmood S.
Powiązania:
https://bibliotekanauki.pl/articles/1178661.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
electrochemical etching
heterojunction
porous silicon
thin films
Opis:
In This paper, electrochemical etching teqniques was using to formation of nano crystalline porous silicon layer on p-type Si substrates. Measurement of capacitance – voltage characteristics at various etching time and current densities were used for calculated built in voltage and type of heterojunction. The built in voltage values were decreased with increasing etching time and current densities for both anisotype Al/PS/p-Si/Al heterojunction. These characteristics are interpreted by assuming the abrupt heterojunction model. The effect of different etching time and current densities on electrical properties of PS have been investigated.
Źródło:
World Scientific News; 2017, 67, 2; 149-160
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel lignocellulosic wastes for comparative adsorption of Cr(VI): equilibrium kinetics and thermodynamic studies
Autorzy:
Haroon, H.
Gardazi, S. M. H.
Butt, T. A.
Pervez, A.
Mahmood, Q.
Bilal, M.
Powiązania:
https://bibliotekanauki.pl/articles/778473.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
chromium VI
equilibrium kinetics
lignocellulosic waste adsorbents
thermodynamics
Opis:
Cr(VI) adsorption was studied for abundantly available low-cost lignocellulosic adsorbents in Pakistan namely, tobacco stalks (TS), white cedar stem (WCS) and eucalyptus bark (EB). Several process variables like contact time, adsorbent dose, pH, metal concentration, particle size and temperature were optimized in batch mode. EB showed high Cr(VI) adsorption of 63.66% followed by WCS 62% and TS 57% at pH 2, which is higher than most of the reported literature. Langmuir isotherm (R2  = 0.999) was well fitted into the equilibrium Cr(VI) data of EB, suggesting homogeneous active sites and monolayer coverage of Cr(VI) onto the EB surface. Freundlich (R2  = 0.9982) isotherm was better fitted to the equilibrium data of TS and WCS, revealing the adsorption sites with heterogeneous energy distribution and multilayer Cr(VI) adsorption. Moreover, the Cr(VI) adsorption of studied adsorbents followed the pseudo-second order kinetic model. Thermodynamic properties were investigated in two temperature ranges, i.e., T1  (303–313 K) and T2  (313–323 K). TS and EB showed the exothermic at T1 and endothermic reactions at T2 with entropy controlled adsorption at the solid-liquid interface, and WCS exhibited an opposite thermal trend with decreasing disorderness at solid-liquid interface as temperature rises. Gibbs free energy (ΔG>0) confirmed the non-spontaneous adsorption process for all studied adsorbents.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 2; 6-15
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ranking criteria for assessment of municipal solid waste dumping sites
Autorzy:
Mahmood, K.
Batool, S. A.
Chaudhary, M. N.
Ul-Haq, Z.
Powiązania:
https://bibliotekanauki.pl/articles/205345.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
MSW dumping facility
hazard assessment
ranking criteria
geographic information system (GIS)
remote
sensing
Opis:
Priority wise channelization of resources is the key to successful environmental management, especially when funds are limited. The study in hand has successfully developed an algorithmic criterion to compare hazardous effects of Municipal Solid Waste (MSW) dumping sites quantitatively. It is a Multi Criteria Analysis (MCA) that has made use of the scaling function to normalize the data values, Analytical Hierarchy Process (AHP) for assigning weights to input parameters showing their relevant importance, and Weighted Linear Combination (WLC) for aggregating the normalized scores. Input parameters have been divided into three classes namely Resident’s Concerns, Groundwater Vulnerability and Surface Facilities. Remote Sensing data and GIS analysis were used to prepare most of the input data. To elaborate the idea, four dumpsites have been chosen as case study, namely Old-FSD, New-FSD, Saggian and Mahmood Booti. The comparison has been made first at class levels and then class scores have been aggregated into environmental normalized index for environmental impact ranking. The hierarchy of goodness found for the selected sites is New-FSD > Old-FSD > Mahmood Booti > Saggian with comparative scores of goodness to environment as 36.67, 28.43, 21.26 and 13.63 respectively. Flexibility of proposed model to adjust any number of classes and parameters in one class will be very helpful for developing world where availability of data is the biggest hurdle in research based environmental sustainability planning. The model can be run even without purchasing satellite data and GIS software, with little inaccuracy, using imagery and measurement tools provided by Google Earth.
Źródło:
Archives of Environmental Protection; 2017, 43, 1; 95-105
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Under Pressure DFT Investigations on Optical and Electronic Properties of PbZrO₃
Autorzy:
Nazir, G.
Tariq, Saad
Afaq, A.
Mahmood, Q.
Saad, S.
Mahmood, A.
Tariq, Samar
Powiązania:
https://bibliotekanauki.pl/articles/1030608.pdf
Data publikacji:
2018-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
density functional theory
optical properties
electronic structure
high pressure
Opis:
In this article, density functional theory has been used to investigate the structural and optoelectronic properties of PbZrO₃ (PZO) under pressure from 0 to 350 GPa. In order to achieve ground state structural stability, generalized gradient approximations has been utilized. By studying electronic properties, indirect band-gap nature of PZO appears to change at 15 GPa to direct band-gap. Optical analysis include under pressure responses of real and imaginary parts of dielectric function, optical conductivity, optical absorption coefficient, energy loss function, refractive index, reflectivity and extinction coefficient. Most of the results have been found to be consistent with literature. Study reveals that static dielectric constant and band-gap are in accordance with the Penn model which validates our computed results. Moreover, static dielectric constant and static refractive index directly increases with pressure. Material preserves its positive value of refractive index at all pressures and therefore, it is not a negative index metamaterial. Plasma frequency increases directly with pressure that destabilize the under study material. Our results could be very useful for developing novel optoelectronic devices based on PZO suitable to work under extreme conditions.
Źródło:
Acta Physica Polonica A; 2018, 133, 1; 105-113
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
USE OF GLUTARIC ACID TO IMPROVE THE SOLUBILITY AND DISSOLUTION PROFILE OF GLIPIZIDE THROUGH PHARMACEUTICAL COCRYSTALLIZATION
Autorzy:
Batool, Fakhra
Ahmad, Mahmood
Minhas, Muhammad U.
Khalid, Qandeel
Idrees, Hafiz A.
Khan, Fahad M.
Powiązania:
https://bibliotekanauki.pl/articles/895470.pdf
Data publikacji:
2019-02-28
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
FTIR
SEM
PXRD
thermal analysis
glipizide
glutaric acid
Opis:
The purpose of current study was to improve the solubility and dissolution profile of BCS class-II drug Glipizide using glutaric acid as a coformer via various cocrystalization techniques i.e., dry grinding, liquid assisted grinding, slurry and solvent evaporation. Fourier Transform Infrared Spectroscopy (FTIR) was performed to determine the interaction between components of glipizide-glutaric acid (GPZ-GLU) cocrystals. Powder X-ray Diffraction (PXRD) studies confirmed the crystalline nature of formulated cocrystals. Scanning Electron Microscopy (SEM) revealed cylindrical to rectangular shape of cocrystals. Flow properties of GPZ-GLU cocrystals were evaluated by micromeritics analysis. Size and surface morphology was determined by zeta sizer analysis and optical microscopy. Differential scanning calorimetry (DSC) and Thermogravimetric (TGA) analysis were performed to determine the melting points as well as thermal stability of pure components and formulated GPZ-GLU cocrystals. In-vitro drug release studies were carried out using dissolution apparatus-II. GPZ-GLU cocrystals showed higher drug release at pH 6.8 as compared to pH 1.2. However, percent drug release of optimum formulations at pH 6.8 was determined as; 24%-92.2% (F3) and 12.0%-93.5% (F7). Solubility studies revealed improved solubility as compared to pure drug in water i.e., 53 folds and 54.27 folds from F3 and F7 cocrystals, respectively. Finally it was concluded that glutaric acid has improved the solubility and dissolution profile of glipizide. However, many cocrystal formers have been reported in literature that can be used to enhance the physicochemical properties as well as bioavailability of poorly soluble drugs via cocrystalization technique.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2019, 76, 1; 103-114
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Buckling and bending properties of aluminium plate with multiple cracks
Autorzy:
Mohmmed, J. H.
Mahmood, N. Y.
Ali, M.
Zainulabdeen, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/1818485.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
buckling stability
bending strength
crack
aluminium plate
ANSYS package
stabilność wyboczeniowa
wytrzymałość na zginanie
pęknięcie
płyta aluminiowa
pakiet ANSYS
Opis:
Purpose: In this paper, the bending strength and buckling stability of (AA 7075-T6) aluminium plate weakened by many transverse cracks, which located at different positions, subjected to concentrated loads applied at the ends were analysed. Design/methodology/approach: Numerical modelling and calculation by the finite element method (ANSYS Package), for the critical load of bending and compression panel were estimated. Findings: It found that the variation of the critical stress in bending and buckling is proportional to the crack conditions (no. of crack and location). In general, the critical load in bending and buckling decreases with increasing the crack number in structure. Research limitations/implications: For both bending and buckling, two transverse cracks on one face of plate is more stable than two transverse cracks on opposite faces. Practical implications: In addition, many experimental tests were carried out by using an INSTRON test machine to obtain the buckling critical loads, where the experimental results were compared with the ones of the finite element method. Furthermore, bending strength was calculated theoretically for the cracked panel. Originality/value: Comparison between the experimental and numerical (FE based model) data and between the theoretical and nu-merical (FE based model) data for buckling and bending strength respectively indicate the precise and the simplicity of the developed models to determine the critical loads in such cases.
Źródło:
Archives of Materials Science and Engineering; 2020, 106, 2; 49--58
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First principle analysis of electronic, optical and thermoelectric characteristics of XBiO3 (X = Al, Ga, In) perovskites
Autorzy:
Mahmood, Q.
Rouf, S. A.
Algrafy, E.
Murtaza, G.
Ramay, S. M.
Mahmood, A.
Powiązania:
https://bibliotekanauki.pl/articles/1818225.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
density functional theory
structural stability
optoelectronics
thermoelectric applications
indirect band gap semiconductors
Opis:
The perovskites XBiO3 (X = Al, Ga, In) have been studied in terms of mechanical, optical and thermoelectric behavior for energy harvesting application. Density functional theory is applied to study electronic, optical and thermoelectric properties of the studied materials. Structural, mechanical and thermodynamic stabilities are confirmed from the tolerance factor, Born mechanical stability and formation energy/specific heat capacity. Poisson and Plough ratios show the studied materials are ductile and have ability to withstand pressure. Band structure analysis shows the indirect band gap 3.0/2.1/1.0 eV for ABO/GBO/IBO. A complete set of optical spectra is reported by dielectric constants, refractive index, optical conduction, absorption of light and optical loss energy. Shifting of maximum absorption band to visible region increases the potential of perovskites XBiO3. Transport characteristics are also investigated by electrical conductivity, Seebeck coefficient and figure of merit.
Źródło:
Opto-Electronics Review; 2020, 28, 1; 8--14
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł

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