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    Wyświetlanie 1-6 z 6
    Tytuł:
    Investigation on the structural, optical and topographical behavior of Cadmium oxide polycrystalline thin films using electrochemical depositing method at different times
    Autorzy:
    Abd, Ahmed N.
    Dawood, Mohammed O.
    Hassoni, Majid H.
    Hussein, Ali A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1192094.pdf
    Data publikacji:
    2016
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Cadmium oxide
    thin film
    optical characteristics of film
    electrochemical depositing method
    Opis:
    The optical and structure properties of Cadmium oxide (CdO) thin film prepared by electrochemical deposition method at different times (15, 30 and 60) min were investigated in this paper. Results of optical Transmission, absorption, reflection spectra, optical conductance, refractive index, extension coefficient, real and imaginary dielectric constants studies are reported. The optical transmittance of the CdO thin film which formed at room temperature was 20% at wavelength ≈350 nm then increases to 60% at wavelength ≈1100 nm for thin film of CdO. The band-gap was also calculated from the equation relating absorption coefficient with the wavelength. The energy band gap changes from 2.3eV (Bulk CdO) to 2.45eV (CdO thin film). The plotted graphs show the optical characteristics of the film which varied with the wavelength and the photon energy. The optical conductance and band-gap indicated that the film is transmitting within the visible range. The dielectric constant and optical conductance of the film initially decreases slowly with increase in photon energy. The extinction coefficient and refractive index of the films also evaluated, which affected with the change in transmittance. The structure of synthesised CdO thin film was analyzed by X-ray diffraction XRD which revealed that the CdO thin film are polycrystalline and have several peaks of cubic face structure. The crystallite size, dislocation density, microstrain and number of dislocations of the thin film were calculated and listed.
    Źródło:
    World Scientific News; 2016, 37; 249-264
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Theoretical model to determine the Porosity and refractive index of porous silicon type-n by using Atomic force microscope
    Autorzy:
    Abdulridha, Wasna'a M.
    Abd, Ahmed N.
    Dawood, Mohammed O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1193012.pdf
    Data publikacji:
    2016
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Atomic Force Microscope
    Porous silicon
    n-PS
    porosity
    refractive index
    thickness
    Opis:
    Porous silicon (PS) layer was produced by photochemical etching process at (5, 7, 10, 12 and 15) etching time and 7 mA/cm2 current density then after investigation by Atomic Force Microscope (AFM) the thickness of PS layer from about 3.4 µm to 15.8 µm was determined. The surface of porous silicon is formed from small pyramids with porous structure, where the porosity of n-PS is from ≈ (32-72%). Porous silicon layer formed on the silicon substrates by photochemical etching contains also the nanopores with diameter about (16.41-42) nm in current density (7mA/cm2). The porosity and thickness was determined from AFM results and compared with the result from the usually measured porosity and thickness through a gravimetric method we found that the values of porosity and thickness calculated from two methods are approximately similar to each other with few difference, the influence of structure changes on optical properties such as refractive index, which decreases exponentially with porosity.
    Źródło:
    World Scientific News; 2016, 28; 29-40
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Proximate analysis of lignocellulosic biomass and its utilization for production, purification and characterization of ligninolytic enzymes by Aspergillus flavus
    Autorzy:
    Khan, Jehangir
    Asad, Muahammad Javaid
    Mahmood, Raja Tahir
    Wattoo, Feeroza Hamid
    Zainab, Tayyaba
    Nazir, Sidrah
    Shah, Muhammad Basir
    Ahmed, Dawood
    Powiązania:
    https://bibliotekanauki.pl/articles/205277.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Aspergillus flavus
    acid detergent lignin
    ammonium sulfate
    ligninolytic enzymes
    Platanus orientalis
    Opis:
    Ligninolytic enzymes are employed for the production of second-generation biofuel to minimize fuel crisis. Additionally, they play a crucial role in global carbon cycle and a variety of applications in food, agriculture, paper and textile industries. On a large scale production of ligninolytic enzymes, microorganisms can be cultured on lignocellulosic wastes. In the present study, proximate analysis including acid detergent lignin (ADL), acid detergent cellulose (ADC), acid detergent fiber (ADF) and acid insoluble ash (AIA) were performed for Platanus orientalis (chinar), Bauhinia variegata (orchid tree), Pinus roxburghii (chirpine), wheat straw and wheat husk. Platanus orientalis was selected as substrate because of higher lignin contents for the production of ligninolytic enzymes by Aspergillus flavus. Solid State Fermentation was used and Response Surface Methodology was employed for optimizing various parameters and enzymes production. Maximum production was achieved at temperature 32°C, fermentation period 120 hours, pH 4.5, inoculums size 3.5 mL, substrate mesh size 80 mm, substrate size 7 g. Maximum purification of laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP) was achieved with 50%, 60% and 40% ammonium sulfate respectively and it was enhanced by gel filtration chromatography. Characterization of enzymes shows that Laccase has 35°C optimum temperature, 4.5 pH, 0.289 mM Km and 227.27 μM/ml Vmax. Manganese peroxidase has 30°C optimum temperature, 5.5 pH, 0.538 mM Km and 203.08 μM/ml Vmax. Lignin peroxidase has 30°C optimum temperature, 3 pH, 2 mM Km and 2000 uM/ml Vmax. Protein concentrations found in crude extracts and partially purified enzymes are respectively: laccase 1.78 and 0.71 mg/ml, MnP 1.59 and 0.68 mg/ml. LiP, 1.70 and 0.69 mg/ml.
    Źródło:
    Archives of Environmental Protection; 2020, 46, 1; 3-13
    2083-4772
    2083-4810
    Pojawia się w:
    Archives of Environmental Protection
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Longitudinal shear in composite deck slabs using corrugated steel sheets
    Autorzy:
    Alkurayshi, Hakim S. M.
    Jawad, Adnan K.
    Dawood, Alaa M.
    Hakim S., Ahmed
    Powiązania:
    https://bibliotekanauki.pl/articles/35540380.pdf
    Data publikacji:
    2021
    Wydawca:
    Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
    Tematy:
    corrugated sheets
    shear transfer
    shear span
    slip
    deflection
    Opis:
    Profile deck steel sheets are used in composite deck slabs. These sheets are standard in dimensions and shapes besides they are supplied with embossments and indentations. Such sheets are not available in Iraqi markets nowadays therefore people used another type of sheets which are corrugated without embossments or indentations in very wide range. This study covers the use of such sheets in composite slabs as decks instead of standard profiled steel sheets. The study comprises testing slabs of dimensions 0.9 × 2.5 m reinforced by steel fabric mesh and rested on corrugated sheets. Two types of shear spans are selected shorter and longer to study the longitudinal shear force transmitted due to the applied loads according to the Eurocode 4. The shorter shear spans are 600, 500 and 400 mm while longer one is 800, 750 and 700 mm. The study extended to support the requirements of design equation of the Eurocode by shear bond method also known as m–k method. The evaluated values of m and k are 0.094 and 65 respectively. The result of k which plays a very important role in shear transfer is small compared to what available in literature, therefore it is recommended to make use of shear connectors in such construction or any else method.
    Źródło:
    Scientific Review Engineering and Environmental Sciences; 2021, 30, 3; 411-423
    1732-9353
    Pojawia się w:
    Scientific Review Engineering and Environmental Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Autonomy of urban light rail transport systems and its influence on users, expenditures, and operational costs
    Autorzy:
    Kostrzewski, Mariusz
    Eliwa, Ahmed
    Dawood, Ahmed
    Powiązania:
    https://bibliotekanauki.pl/articles/2203863.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
    Tematy:
    light rail
    transport system
    autonomy
    automation
    expenditures
    operational cost
    lekka kolej miejska
    system transportu
    autonomia
    automatyzacja
    wydatki
    koszty operacyjne
    Opis:
    The aim of this paper is to study and highlight various effects of automizing urban light rail transport systems by examining the impact of such structures on common users, as well as the expenditures and operational costs involved. By providing an overview of different transportation networks through the three categories of expenditure— transportation, maintenance, and administration—an idea of the general operational cost can be established. Additionally, by indicating the aforementioned cost, the effect of the grade of automation on costs can be determined and explained. However, this paper does not include an attempt to estimate these costs; it only states what may affect such costs. Furthermore, the factor of safety is considered by underlining the changes expected to occur with the implementation of such networks. The implementation of autonomous rail systems would result in lower operational costs, which is discussed in this paper based on another study. At the same time, the factor of safety was also observed as simultaneously increasing, as were the overall experiences of users, both in terms of aesthetics and function. The only setback found by the research is that some users would be reluctant to use a network without an operator.
    Źródło:
    Transport Problems; 2022, 17, 4; 165--175
    1896-0596
    2300-861X
    Pojawia się w:
    Transport Problems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design and Simulation of 2× 2Micro Strip Circular Patch Antenna Array at 28 GHz for 5G Mobile Station Application
    Autorzy:
    Hasan, Salim Abdullah
    Ahmed, Abdulsattar Mohamed
    Abdulqader, Mohanad Nawfal
    Dawood, Younis Shareef
    Powiązania:
    https://bibliotekanauki.pl/articles/2200728.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    patch
    5G
    return loss
    dielectric
    array
    divider
    substrate
    directivity
    bandwidth
    Opis:
    This paper proposes the design and simulation of 2×2 circular patch antenna array working at 28 GHz by using four inset feed micro strip circular patch antennas to achieve beam forming with directivity around 13dB which is required to overcome part of high path loss challenge for high data rate mm-5G mobile station application. Four element 2x2 array consists of two 1x2 circular patch antenna arrays based on power divider and quarter wavelength transition lines as a matching circuit. The designed antenna array is simulated on RT/duroid 5880 dielectric substrate with properties of 0.5mm thickness, dielectric constant ε r =2.2, and tangent loss of 0.0009 by using Computer System Technology (CST) software. The performances in terms of return loss, 3D–radiation pattern is evaluated at 28 GHz frequency band. The design also includes the possibility of inserting four identical 2x2 antenna arrays at four edges of mobile station substrate to achieve broad space coverage by steering the beams of the mobile station arrays.
    Źródło:
    International Journal of Electronics and Telecommunications; 2022, 68, 4; 721--729
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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