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Wyszukujesz frazę "Ahmadi, M." wg kryterium: Autor

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    Wyświetlanie 1-23 z 23
    Tytuł:
    Cutoff grade optimization based on maximizing net present value using a computer model
    Autorzy:
    Ahmadi, M. R.
    Powiązania:
    https://bibliotekanauki.pl/articles/91898.pdf
    Data publikacji:
    2018
    Wydawca:
    Główny Instytut Górnictwa
    Tematy:
    cut-off grade optimization
    maximization of net present value
    Lane's theory
    computer model
    optymalizacja doboru granicy opłacalności
    maksymalizacja wartości bieżącej netto
    teoria Lane’a
    model komputerowy
    Opis:
    After designing the final range of open pit mines, one of the first essential decisions to be made in the production planning framework is to determine the cutoff grade. The cutoff grade of mines, due to interconnections with technical and economic parameters, is one of the most important parameters for the design of open pit mines. Considering the fundamental role of plant cutoff grade on the economical operation of a mine, the optimal selection of this grade is of great importance. One of the main problems in mining operations is how to determine the optimal cutoff grades of ore deposits at different periods during the life of a mine, it can be considered based on one of the goals of maximizing annual profit or net present value extraction during the mining period. Despite the existence of a range of different techniques for determining the optimal cutoff grade, Lane's algorithm is usually the most widely used cutoff grade optimization technique, which is calculated taking into account the technical and economic factors of production. Cutoff grade optimization with the goal of maximizing the net present value over the years of the mine's life, as well as the correlation with the distribution of the grade and tonnage of the remaining ore, requires a long calculation process, especially for large mines. In this research, optimal cutoff grade programming based on Lane's theory and aimed at maximizing the net present value in MATLAB software (computer model) has been carried out. Mineral operations consist of three phases: mining, processing, and refining. In single-product and single-process mode, the optimum cut-off grade and the net present value of production are calculated for each year of the mine's life. After validating the outputs of the model, the implementation of the computer model based on the data of Gol Gohar iron mine No.1 in a five-year plan was carried out. The changes in optimal cutoff grade and changes in net present value from 48.65% to 18,582 billion rials in the early years of the mine increased to 40.5% and approximately 3000 billion rials at the end of the mine's life.
    Źródło:
    Journal of Sustainable Mining; 2018, 17, 2; 68-75
    2300-1364
    2300-3960
    Pojawia się w:
    Journal of Sustainable Mining
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonlinear vibration analysis of prebuckling and postbuckling in laminated composite beams
    Analiza drgań nieliniowych przed i po wyboczeniu laminowanych belek kompozytowych
    Autorzy:
    Abdollahzadeh, G.
    Ahmadi, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/230118.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    drgania nieliniowe
    belka kompozytowa
    metoda analityczna
    wyboczenie
    nonlinear vibration
    composite beam
    analytical method
    buckling
    Opis:
    In this study, we attempt to analyse free nonlinear vibrations of buckling in laminated composite beams. Two new methods are applied to obtain the analytical solution of the nonlinear governing equation of the problem. The effects of different parameters on the ratio of nonlinear to linear natural frequencies of the beams are studied. These methods give us an agreement with numerical results for the whole range of the oscillation amplitude.
    Niniejsze opracowanie podejmuje temat analizy swobodnych drgań nieliniowych wyboczenia laminowanych belek kompozytowych. Zastosowano dwie nowe metody w celu uzyskania rozwiązania w postaci kluczowego równania nieliniowego, opisującego ten problem. Przestudiowano wpływ różnych parametrów na stosunek częstotliwości drgań nieliniowych do drgań liniowych w odniesieniu do badanych belek. Metody te umożliwiły nam weryfikację otrzymanych wyników dla całego zakresu amplitudy oscylacji.
    Źródło:
    Archives of Civil Engineering; 2015, 61, 2; 161-178
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nutrient uptake, proline content and antioxidant enzymes activity of pepper (Capsicum annuum L.) under higher electrical conductivity of nutrient solution created by nitrate or chloride salts of potassium and calcium
    Autorzy:
    Ahmadi, M.
    Souri, M.K.
    Powiązania:
    https://bibliotekanauki.pl/articles/12611712.pdf
    Data publikacji:
    2019
    Wydawca:
    Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
    Tematy:
    plant cultivation
    chilli pepper
    Capsicum annuum
    nutrient uptake
    proline content
    antioxidant enzyme
    electrical conductivity
    nutrient solution
    chloride salt
    potassium salt
    calcium salt
    Opis:
    This study was conducted to evaluate the effects of higher conductivity of nutrient solution created by nitrate or chloride salts of potassium and calcium on growth characteristics of pepper plants (Capsicum annuum var annuum) during four months of growth period. Two EC5 and EC8 dS/m of Hoagland nutrient solutions were prepared using various salt combinations, namely: KCl + CaCl2, KNO3 + CaNO3, and KNO3 + CaNO3 + NaCl. Hoagland nutrient solution with EC 1.8 dS/m served as a control. Higher conductivity treatments had different effects on pepper plant growth. The most significant reduction in growth parameters of plant height, shoot fresh weight, fruit yield and nutrients uptake was in plants treated with KCl + CaCl2 particularly at EC8. Application of KNO3 + CaNO3 particularly at EC5, showed no difference as compared to the control regarding many growth parameters. Application of KNO3 + CaNO3 at EC5 resulted in higher shoot fresh weight compared to the control. All salinity treatments, except from KNO3 + CaNO3 at EC5, reduced the fruit yield compared to the control. Treatments of KCl + CaCl2 and KNO3 + CaNO3 + NaCl particularly at EC8 of nutrient solution, resulted in higher leaf proline concentration, catalase and peroxidase enzymes activity compared to the control. Other conductivity treatments showed no difference in catalase or peroxidase enzymes activities. Significantly the lowest amount of leaf N, K, Mg and Ca was in KCl + CaCl2 at EC8. On the other hand, the highest leaf macronutrient concentrations were in KNO3 + CaNO3 at EC5 and/or EC8 that showed only higher leaf N and Ca values compared to the control. Leaf micronutrient concentrations were the highest in KNO3 + CaNO3 at EC5 that generally showed no difference with control plants. However, application of KCl + CaCl2 particularly at EC8 and to less extent KNO3 + CaNO3 + NaCl at EC8, reduced the leaf micronutrient concentrations. Application of KNO3 + CaNO3 at EC5 increased and KCl + CaCl2 or KNO3 + CaNO3 + NaCl at EC8 decreased the leaf Fe concentration compared to control plants.
    Źródło:
    Acta Scientiarum Polonorum. Hortorum Cultus; 2019, 18, 5; 113-122
    1644-0692
    Pojawia się w:
    Acta Scientiarum Polonorum. Hortorum Cultus
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characteristics of GZO/IZO Dual-Layer as an Electron Transport Layer in Dye-Sensitized Solar Cell
    Autorzy:
    Manzari Tavakoli, M. H.
    Ahmadi, M.
    Sabet, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/353232.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    dual-layer
    sol-gel
    spin coating
    thin film
    GIZO
    solar cell
    Opis:
    GZO/IZO semiconductor thin films were prepared on the ITO substrate via sol-gel spin coating method for using in the dye-sensitized solar cells (DSSCs). For this purpose, GZO and IZO thin films were optimized by the percentage of doping gallium and indium in zinc oxide and were studied their electrical, optical and structural properties. After that, the layers with the best performance were selected for use in the DSSCs. The concentration of all solutions for spin coating processes was 0.1 M and zinc oxide has been doped with gallium and indium, with different doping percentages (0, 0.5, 1, 2 and 4 volume percentage). So, by studying the properties of the fabricated thin films, it was found the films with 0.5%GZO and 0.5%IZO have the best performance and hence, the optimized dual-layer (0.5% GZO/0.5% IZO (GIZO)) were prepared and studied their electrical and optical properties. The synthesized optimized dual-layer film was successfully used as the working electrode for dye-sensitized solar cells. The sample with 0.5%IZO shows the 9.1 mA/cm2 short-circuit current density, 0.52 V open circuit voltage, 63% fill factor and 2.98% efficiency.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 4; 1609-1614
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Removal of benzotriazole by Photo-Fenton like process using nano zero-valent iron: response surface methodology with a Box-Behnken design
    Autorzy:
    Ahmadi, M.
    Rahmani, K.
    Rahmani, A.
    Rahmani, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/779500.pdf
    Data publikacji:
    2017
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    benzotriazole
    Photo-Fenton
    Response surface methodology
    Box-Behnken
    Opis:
    In this paper, the removal of benzotriazole (BTA) was investigated by a Photo-Fenton process using nano zero valent iron (NZVI) and optimization by response surface methodology based on Box-Behnken method. Effect of operating parameters affecting removal efficiency such as H2O2, NZVI, and BTA concentrations as well as pH was studied. All the experiments were performed in the presence of ultraviolet radiation. Predicted levels and BTA removal were found to be in good agreement with the experimental levels (R2 = 0. 9500). The optimal parameters were determined at 60 min reaction time, 15 mg L-1 BTA, 0.10 g L-1 NZVI, and 1.5 mmol L-1 H2O2  for Photo-Fenton-like reaction. NZVI was characterized using X-ray diffraction (XRD), transmission electron microscope (TEM) images, and scanning electron microscope (SEM) analysis.
    Źródło:
    Polish Journal of Chemical Technology; 2017, 19, 1; 104-112
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermally activated persulfate treatment and mineralization of a recalcitrant high TDS petrochemical wastewater
    Autorzy:
    Jorfi, S.
    Pourfadakari, S.
    Ahmadi, M.
    Akbari, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/779544.pdf
    Data publikacji:
    2017
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    Industrial wastewater treatment
    Thermally activation
    persulfate Petrochemical industry
    High TDS wastewater
    Opis:
    Thermally activated persulfate efficiency for the treatment of a recalcitrant high TDS wastewater was investigated. The specific character of studied wastewater was high TDS content of around 23820 mg/L and BOD5/COD ratio of 0.07. Effective operational parameters including initial pH values of 3–9, reaction temperature of 40–80°C and persulfate concentrations of 0.5–5 g/L for COD removal were investigated in batch mode experiments. Removal efficiency was pH and temperature dependent. The COD and TOC removal of 94.3% and 82.8% were obtained at persulfate concentration of 4 g/L, initial pH value of 5 and temperature of 70°C after 180 min for initial COD concentration of 1410 mg/L. The pseudo first-order kinetic model was best fitted with COD removal (R2  = 0.94).
    Źródło:
    Polish Journal of Chemical Technology; 2017, 19, 2; 72-77
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characteristics of postharvest quality of chrysanthemum cut flowers under pretreatment with nitrogenous compounds
    Autorzy:
    Souri, M.K.
    Goodarzizadeh, S.
    Ahmadi, M.
    Hatamian, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/11865013.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
    Tematy:
    plant cultivation
    chrysanthemum
    ornamental plant
    flowering plant
    cut flower
    shelf life
    postharvest quality
    pretreatment
    nitrogenous nutrient
    ammonium
    carotenoid
    Opis:
    This study was done using three nitrogenous compounds to evaluate their effects on postharvest characteristics of chrysanthemum (Chrysanthemum indicum) cut flowers. The study consisted of three separate and parallel experiments, in which ammonium sulfate, calcium nitrate and potassium nitrate were used in different concentrations of zero, 50, 100, 200 and 500 mg dm ‒3 N for pretreatment of stems for 6 hour before transferring to holding d-water solution. The results showed that petal ion leakage and leaf SPAD values were increased by increasing ammonium sulfate, but not calcium or potassium nitrate. Petal carotenoids were increased by pretreatment of ammonium sulfate and potassium nitrate. There was constant increase in water uptake by increasing the levels of calcium nitrate and potassium nitrate, while ammonium sulfate at high concentrations (200 and 500 mg dm ‒3 N) resulted in significant less water uptake compared to control. Ammonium sulfate in 50 and 100 mg dm ‒3 increased shelf life of pretreated stems, but higher concentrations significantly reduced cut flowers shelf life. Increasing concentrations of calcium nitrate and particularly potassium nitrate have led to prolongation of flower shelf life to 12 days compared to 6 days of control. The results indicate that pretreatment of chrysanthemum cut flowers with ammonium sulfate in rather low concentrations or with moderate to high concentrations of calcium nitrate or potassium nitrate can significantly improve shelf life and postharvest flower qualities.
    Źródło:
    Acta Scientiarum Polonorum. Hortorum Cultus; 2018, 17, 3; 83-90
    1644-0692
    Pojawia się w:
    Acta Scientiarum Polonorum. Hortorum Cultus
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    First observation of vertically aligned cesium doped ZnO nanorods as an efficient electron transporter in polymer solar cell
    Autorzy:
    Ahmadi, M.
    Rashidi Dafeh, S.
    Ghazanfarpour, S.
    Khanzadeh, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/355661.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    inverted polymer solar cell
    Cs doped ZnO nanorod
    electron transporter
    Opis:
    Single crystalline cesium doped ZnO nanorods with homogeneous size and shape were grown hydrothermally on ITO substrates that are presented in our previous work. According to the previous work, XRD analysis showed that cesium doped ZnO nanorods are wurtzite single crystals and are grown preferentially along the c-axis. Also, the electrical conductivity of doped ZnO showed higher values for the 1% cesium, which confirmed incorporation of the cesium dopant. Cesium doped ZnO nanorods are suitable candidates for applications in solar cells. So, in this research, we employed cesium doped ZnO nanorods with the different dopant concentration in inverted polymer solar cell. By comparing the effect of doped ZnO nanorods with diverse dopant concentration (0, 0.5, 1.0, 1.5 and 2%) on the performance of devices, 1.0% cesium doped ZnO was found as the most effective doping level among the selected doping concentrations. Also, using 1.0% cesium doped ZnO nanorods, Jsc of 8.21 mA/cm2, Voc of 0.541V and Fill Factor of 63.01% were achieved, which led to power conversion efficiency of 2.80%.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 4; 1571-1574
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Enhancement the conditioning of waste activated sludge through a sequence of freeze/thaw-electro-Fenton process
    Autorzy:
    Shahheidar, N.
    Jorfi, S.
    Takdastan, A.
    Jaafarzadeh, N.
    Ahmadi, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/779096.pdf
    Data publikacji:
    2018
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    Sludge conditioning
    freeze
    thaw
    electro-Fenton
    Opis:
    Sludge conditioning is an important stage in sludge management. In the present study, a sequence of freeze/thaw-electro-Fenton process was designed and specific resistance filtration (SRF) was monitored during sludge conditioning as an important factor in sludge dewaterability. Furthermore, protein and polysaccharide concentrations were measured during the experiments. Results showed that the lowest SRF value contributed to −10°C in freezing process which showed a reducing trend by decreasing solution pH. In addition, results revealed that solution pH less than 3 caused a significant improvement in sludge dewatering; so the lowest SRF has been registered at pH = 2. By increasing current intensity from 0.5 to 1A, SRF values were reduced and then followed by an enhancement with increasing current intensity to 3.2 A. The lowest SRF value (6.1 × 104 m/kg) was obtained at H2O2 = 30 mg/L which was the best conditions for sludge dewatering.
    Źródło:
    Polish Journal of Chemical Technology; 2018, 20, 1; 47-53
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An optimum level of nano-selenium supplementation of a broiler diet according to the performance, economical parameters, plasma constituents and immunity
    Autorzy:
    Ahmadi, M.
    Poorghasemi, M.
    Seidavi, A.
    Hatzigiannakis, E.
    Milis, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/1192473.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
    Tematy:
    broiler
    nutrition
    nanotechnology
    selenium
    production traits
    immunity
    Opis:
    An optimum nano-Se content in a diet of highly productive broilers has not been defined yet. Meanwhile, there are contradictory reports regarding effects of nano-Se on production traits and the etiology of possible positive effects. The aims of the present study were to test the hypothesis that low levels of nano-Se can improve productivity and metabolic functions during a 42-day-long broiler production cycle, to determine an optimum nano-Selenium (nano-Se) concentration of the diet, and finally to explore the etiology of these effects. One-hundred-eighty 1-day-old, male, Ross 308 broiler chicks were used in a completely randomized experiment, where the birds were placed in experimental pens, in three replicate pens of 10 chicks each, making a total of 18 experimental units. They were assigned diets with different nano-Selenium levels. All birds were fed an almost identical diet from 1 until 42 d, different only in the nano-Se content, namely: 1) control (CON) group 0.0 nano-Se, 2) NS1 group 0.1 mg kg-1 dietary nano-Se, 3) NS2 group 0.2 mg kg-1 dietary nano-Se, 4) NS3 group 0.3 mg kg-1 dietary nano-Se, 5) NS4 group 0.4 mg kg-1 dietary nano-Se, 6) NS5 group 0.5 mg kg-1 dietary nano-Se, supplied from 1 to 42 day of life. The significance level was declared at P<0.05. The final bird weight was higher and production cost was lower in NS3 and NS4 groups compared to CON, NS1 and NS5. The weight of an eviscerated carcass was lower in CON group compared to the other groups. The serum blood parameters as well as the weight of organs related with the immune system were not significantly different between groups. Nano-Se supplementation positively affected body weight gain (BWG) and feed conversion ratio (FCR). Higher BWG was achieved owing to better FCR rather than higher feed intake. The supplementation of 0.3-0.4 mg nano-Se kg-1 is the optimum level to be added as a feed additive in broiler diets, increasing animal productivity and diminishing environmental impact
    Źródło:
    Journal of Elementology; 2020, 25, 3; 1187-1198
    1644-2296
    Pojawia się w:
    Journal of Elementology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of temperature regimes on seed germination asafoetida (Ferula assafoetida L.)
    Autorzy:
    Zangoie, M.
    Parsa, S.
    Mahmoodi, M.
    Al-Ahmadi, M. Jami
    Sanjari, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/2199584.pdf
    Data publikacji:
    2014-06-19
    Wydawca:
    Instytut Hodowli i Aklimatyzacji Roślin
    Tematy:
    asafetida
    constant temperature
    fluctuating temperature
    medicinal plants
    seed biology
    Opis:
    Asafoetida is a medicinal plant belonging to the Apiaceae family. Gum obtained from the lower part of the stem and roots of this plant has many industrial and pharmaceutical applications. This plant is subject to extinction in its natural habitats due to over-utilization. Understanding the biology of seed germination can help to restore such degradation by implementing agricultural development programs. The present study is an attempt to determine the germination responses to two temperature regimes (constant and fluctuating) during the course of the study. The experiment was planned based on a factorial-completely randomized design with two factors (constant and fluctuating temperature regimes) at 3 levels each (15, 20 and 25°C) with 4 replications. The results showed that the characteristics of germination in asafoetida were significantly improved under the fluctuating temperature as compared with the constant regime. It showed a mean germination time of 1.88 days for the fluctuating regime, while it was 4.88 days for the constant regime. The same results were found on germination rates in favor of fluctuating (0.62 per day) in comparison with constant regime (0.33 per day). Under the fluctuating regime, the lowest level of imposed temperature (daily application of 10 and 20 degree during the first and the second 12 hours, respectively) was the best for seed germination in this experiment.
    Źródło:
    Plant Breeding and Seed Science; 2014, 69; 59-67
    1429-3862
    2083-599X
    Pojawia się w:
    Plant Breeding and Seed Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Earthquake analysis of arch dams including the effects of foundation discontinuities and proper boundary conditions
    Autorzy:
    Ferdousi, A.
    Mostafa Gharabaghi, A. R.
    Ahmadi, M. T.
    Chenaghlou, M. R.
    Emami Tabrizi, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/279306.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    concrete arch dam
    non-homogeneous and discontinuous rock foundation
    nonlinear dynamic analysis
    boundary conditions
    Opis:
    The interaction between dam foundation and rocks plays a significant role in the design and analysis of concrete arch dams. In the current study, comprehensive dynamic analysis of the dam-reservoir-foundation system is performed by developing a non-linear finite element program. The objective of this paper is to study the seismic behavior of a concrete arch dam taking into account the effects of foundation discontinuities and foundation inhomogeneity on the stability. Proper modeling truncated boundary conditions at the far-end of the foundation and reservoir fluid domain as well as to correctly apply the in-situ stresses for the foundation rock represents field conditions in the model more realistically. In this paper, the nonlinear seismic response of the dam-reservoir-foundation system includes dam-canyon interaction, dam body contraction joint opening, discontinuities (possible sliding planes) of the foundation rock and the failure of the joined rock and concrete materials. The results for the Karun 4 dam as a case study revealed the substantial effect of modeling discontinuities and boundary conditions of the rock foundation under seismic excitation that needs to be considered in the design of new dams and can be applied to seismic safety evaluation of the existing dams.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2014, 52, 3; 579-594
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Adsorption of Cr(VI) by Natural Clinoptilolite Zeolite from Aqueous Solutions: Isotherms and Kinetics
    Autorzy:
    Jorfi, S.
    Ahmadi, M. J.
    Pourfadakari, S.
    Jaafarzadeh, N.
    Soltani, R. D. C.
    Akbari, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/778561.pdf
    Data publikacji:
    2017
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    Adsorption
    Clinoptilolite Zeolite
    Cr(VI)
    Isotherm
    Reaction Kinetics
    Opis:
    The main aim of this study was to evaluate the efficiency of natural zeolite for Cr(VI) removal from aqueous solutions. Following simple modification of adsorbent, the effect of operational parameters including pH (2–10), adsorbent dosage (2–20 g/L), contact time (5–150 min) and Cr(VI) concentration (10–50 mg/L) were studied according to one-factor-at-a-time procedure. The maximum Cr(VI) removal of 99.53% was obtained at initial pH of 2, contact time of 30 min, adsorbent dosage of 8 g/L and initial chromium concentration of 10 mg/L. The Freundlich isotherm was best fitted with experimental data (R2 = 0.951). Also, type 1pseudo second order kinetic model showed the most correlation (R2 = 1) with the experimental data. According to obtained results, it can be concluded that the application of clay-like adsorbents such as natural clinoptilolite zeolite can be considered as an efficient alternative for final treatment of effluents containing Cr(VI).
    Źródło:
    Polish Journal of Chemical Technology; 2017, 19, 3; 106-114
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    New hardware engine for new operating systems
    Autorzy:
    Ahmadi, N.
    Kaveh, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/11375.pdf
    Data publikacji:
    2013
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    hardware engine
    new system
    operating system
    genetic algorithm
    chromosome
    genetic diversity
    problem solution
    Opis:
    Genetic algorithm is a soft computing method that works on set of solutions. These solutions are called chromosome and the best one is the absolute solution of the problem. The main problem of this algorithm is that after passing through some generations, it may be produced some chromosomes that had been produced in some generations ago that causes reducing the convergence speed. From another respective, most of the genetic algorithms are implemented in software and less works have been done on hardware implementation. Our work implements genetic algorithm in hardware that doesn’t produce chromosome that have been produced in previous generations. In this work, most of genetic operators are implemented without producing iterative chromosomes and genetic diversity is preserved. Genetic diversity causes that not only don’t this algorithm converge to local optimum but also reaching to global optimum. Without any doubts, proposed approach is so faster than software implementations. Evaluation results also show the proposed approach is faster than hardware ones.
    Źródło:
    International Letters of Natural Sciences; 2013, 05
    2300-9675
    Pojawia się w:
    International Letters of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On new aging classes based on the reversed mean residual life order
    Autorzy:
    Ahmadi, K.
    Rezaei, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/205810.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    reversed mean residual life
    stochastic order
    aging class
    preservation
    characterizations
    IRMR
    Opis:
    In this paper, we introduce new concepts of aging for lifetime distributions. The main idea is the comparison between reversed mean residual life of the random variables X and (X − t | X > t), for all t > 0. Firstly, with some examples, we highlight the role of the proposed aging classes in reliability and life testing. Then, we try to find the connection between the new aging classes and other aging classes well-known from the literature. Reliability properties of the new classes are studied. Formally, we derive the preservation property under monotonic transformations. Some Rother characterization and implications are studied.
    Źródło:
    Control and Cybernetics; 2013, 42, 3; 727-737
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of neural networks for the prediction of rock fragmentation in Chadormalu iron mine
    Zastosowanie sieci neuronowych do prognozowania stopnia rozdrobnienia skał w kopalni rud żelaza w Chadormalu
    Autorzy:
    Monjezi, M.
    Ahmadi, Z.
    Khandelwal, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/219333.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    stopień rozdrobnienia
    prace strzałowe
    sztuczna sieć neuronowa (ANN)
    kopalnia rudy żelaza Charnomalu
    fragmentation
    blasting operations
    ANN
    Chadormalu iron mine
    Opis:
    Most open-pit mining operations employ blasting for primary breakage of the in-situ rock mass. Inappropriate blasting techniques can result in excessive damage to the wall rock, decreasing stability and increasing water influx. In addition, it will result in either over and/or under breakage of rocks. The presence of over broken rocks can result in decreased wall stability and require additional excavation. In contrast, the presence of under broken rocks may require secondary blasting and additional crushing. Since blasting is a major cost factor, both cases (under and over breakage) create additional costs reflected in the increase of the operation and maintenance of the machinery. Quick and accurate measurements of fragment size distribution are essential for managing fragmented rock and other materials. Various fragmentation measurement techniques are available and are being used by industry/researchers but most of the methods are time consuming and not precise. An ideally performed blasting operation enormously influences the overall mining cost. This aim can be achieved by proper prediction and attenuation of fragmentation. Prediction of fragmentation is essential for optimizing blasting operation. Poor performance of the empirical models for predicting fragmentation has urged the application of new approaches. In this paper, artificial neural network (ANN) method is implemented to develop a model to predict rock fragmentation size distribution due to blasting in Chadormalu iron mine, Iran. In the development of the proposed ANN model, ten parameters such as UCS, drilling rate, water content, burden, spacing, stemming, hole diameter, bench height, powder factor and charge per delay were incorporated. Training and testing of the model was performed by the back-propagation algorithm using 97 datasets. A four-layer ANN was found to be optimum with architecture of 10-7-5-1. A comparison has made between measured results of fragmentation with predicted results of fragmentation by ANN and multiple regression model. Sensitivity analysis was also performed to understand the effect of each influencing parameters on rock fragmentation.
    W większości kopalń odkrywkowych stosuje się prace strzałowe w celu wstępnego rozbicia skał górotworu in situ. Niewłaściwe prowadzenie prac strzałowych spowodować może nadmierne uszkodzenie skał, obniżając stabilność górotworu i powodując zwiększony napływ wód. Ponadto, prowadzić może do nadmiernego lub niedostatecznego rozdrobnienia skał. Obecność nadmiernie rozdrobnionych skał spowodować może zmniejszenie stabilności ścian i wymaga dodatkowego odgruzowania. Z kolei obecność niedostatecznie rozdrobnionych skał powoduje konieczność ponownego wykonania prac strzałowych celem rozdrobnienia dalszego skały. Z uwagi na to, że prace strzałowe stanowią zasadniczy element kosztów, obydwa przypadki (niedostateczne lub nadmierne rozdrobnienie skał) mogą pociągać za sobą dodatkowe koszty, odzwierciedlone w zwiększonych kosztach eksploatacji sprzętu. Szybkie i dokładne pomiary rozkładu wielkości fragmentów skał są niezbędne dla zapewnienia właściwej gospodarki rozdrobnionymi skałami i pozostałymi materiałami. Istnieje wiele metod pomiarów i są one szeroko wykorzystywane przez badaczy oraz w przemyśle, jednakże większość metod okazuje się czasochłonna i niewystarczająco dokładna. Idealne przeprowadzenie prac strzałowych w znacznym stopniu przyczynia się do ograniczenia kosztów prowadzenia prac górniczych. Cel ten osiągnąć można poprzez odpowiednie prognozowanie i kontrolowanie stopnia rozdrobnienia. Prognozowanie konieczne jest dla optymalizacji prowadzenia prac strzałowych. Niska skuteczność metod empirycznych wykorzystywanych do prognozowania stopnia rozdrobnienia skał stanowi zachętę do stosowania nowego podejścia. W artykule przedstawiono zastosowanie metody sztucznych sieci neuronowych (ANN) do opracowania modelu prognozowania rozkładu wielkości skal rozdrobnionych w wyniku prac strzałowych w kopalni Chadormalu, w Iranie. W opracowanym modelu ANN uwzględniono dziesięć parametrów: wytrzymałość skały na ściskanie jednoosiowe (UCS), prędkość wiercenia, zawartość wody, rodzaj nadkładu, rozstawienie, rodzaj przybitki, wysokość ławy, rodzaj materiału wybuchowego oraz wielkość ładunku w stosunku do zwłoki czasowej. Uczenie i testowanie modelu odbywa się przy użyciu algorytmu propagacji wstecznej (back-propagation) z wykorzystaniem 97 baz danych. Stwierdzono, że optymalna sieć złożona jest z czterech warstw a jej architekturę opisać można jako 10-7-5-1. Wyniki pomiarów stopnia rozdrobnienia porównano z wyniki prognoz stopnia rozdrobnienia przeprowadzonych przy pomocy sieci neuronowej w oparciu o metodę regresji wielokrotnej. Przeprowadzono analizę wrażliwości dla lepszego zrozumienia wpływu poszczególnych parametrów na stopień rozdrobnienia skały.
    Źródło:
    Archives of Mining Sciences; 2012, 57, 3; 787-798
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of systemic effects of four plant extracts compared with two systemic pesticides, acetamiprid and pirimicarb through leaf spraying against Brevicoryne brassicae L. (Hemiptera: Aphididae)
    Autorzy:
    Shafiei, F.
    Ahmadi, K.
    Asadi, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/66810.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    systemic effect
    plant extract
    pesticide
    acetamiprid
    pirimicarb
    leaf
    spraying
    Brevicoryne brassicae
    Hemiptera
    Aphididae
    cabbage aphid
    aphid
    plant pest
    toxicity
    Opis:
    Aphids are one of the most important economic pests and vectors of viral diseases in crops. Brevicoryne brassicae L., one of the most serious aphid pests in Brassicaceae, if not controlled, often reaches very high densities. The present study compared the systemic effects of ethanolic, methanolic and aqueous Melia azedarach L., Peganum harmala L., Calendula officinalis L. and Otostegia persica Boissier extracts with two systemic pesticides, acetamiprid and pirimicarb (at the maximum label-recommended rate). Population growth percentages of B. brassicae through leaf spraying under greenhouse conditions were assessed. The chemicals were sprayed on one of the leaves in greenhouse condition. The results indicated that all the plant extracts have systemic effects at different levels. Among different extracts, O. persica ethanolic extract, P. harmala methanolic extract and M. azedarach aqueous extract resulted in a reduction of the B. brassicae population
    Źródło:
    Journal of Plant Protection Research; 2018, 58, 3
    1427-4345
    Pojawia się w:
    Journal of Plant Protection Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Assessment of safflower for susceptibility to Pythium ultimum, the causal agent of damping-off.
    Autorzy:
    Pahlevani, M.
    Ahmadi, A.
    Razavi, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2199591.pdf
    Data publikacji:
    2010-12-01
    Wydawca:
    Instytut Hodowli i Aklimatyzacji Roślin
    Tematy:
    disease
    resistance
    seed
    seedling
    soil
    Opis:
    Genetic resistance against Pythium species would be an efficient control of this major seed and seedling fungal pathogen in safflower (Carthamus tinctorius), but so far no source has been identified. Therefore, identifying and then incorporating genetic resistance into the cultivars would be an ideal method of control for this disease. So in this study the resistance to seed rot and damping-off caused by Pythium ultimum among seventeen genotypes of safflower collected from all major production regions of the crop in Iran and some other countries was investigated. Pythium ultimum, previously identified as the most prevalent Pythium isolates on safflower, were used to infest the sterilized soil, which was seeded with safflower genotypes in greenhouse conditions. The experiment was conducted as a split plot design in which sterile and Pythium-infested soils were considered as main plots, and seventeen genotypes of safflower were sub plots. In sterile media, percent of seedling emergence (SES) and in Pythium-infested media, percent of seedling emergence (SEI), percent of diseased seedlings (DSI), percent of uninfected seedlings (USI) and percent of non-emerged seeds (NSI) were recorded. Symptoms showed that in safflower, damping-off occurred in both forms of pre and post emergence. Genotypic variation was existed for level of susceptibility to P. ultimum. Significant differences in SES and SEI were detected among safflower genotypes (P < 0.01), and a significant correlation between SES and seed weight (P < 0.05); SES with SEI (P < 0.05) were detected. Result showed that between evaluated genotypes there wasn’t any genotype with complete resistance (100%) to P. ultimum, so the susceptibilities were assayed. Based on the assessed variables, genotypes LRV-55-295, Aceteria, PI-250537 and IL-111 appear to be highly susceptible to the Pythium infection, whereas 34040, Arak281, and Isfahan were the least susceptible to the disease. Further research will be conducted to determine whether the resistance detected in these genotypes is heritable...
    Źródło:
    Plant Breeding and Seed Science; 2010, 62; 17-30
    1429-3862
    2083-599X
    Pojawia się w:
    Plant Breeding and Seed Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improvement of chalcopyrite atmospheric leaching using controlled slurry potential and additive treatments
    Autorzy:
    Jafari, M.
    Karimi, G.
    Ahmadi, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/110092.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    chalcopyrite
    improved leaching
    controlled oxidation-reduction potential
    additive treatment
    pyrite
    sodium chloride
    silica
    Opis:
    In this study, the synergistic effects of the oxidation-reduction potential (ORP) of leaching slurry and additives (pyrite, sodium chloride and silica) on chalcopyrite atmospheric leaching were investigated. According to the best results of leaching experiments, in the optimum ORP range of 410-430 mV, galvanic (pyrite mass ratio of 4:1), chemical (1.5 mol/dm3 sodium chloride concentration), galvanochemical (pyrite mass ratio of 4:1 and 1.5 mol/dm3 sodium chloride concentration) and mechanical (30 g/dm3 silica concentration) treatments provided 29.8, 46.4, 48.6 and 6.7% increase in the copper recovery, respectively. In galvanic treatments, effective surface corrosion of chalcopyrite was the reason for enhanced chalcopyrite dissolution. In chemical and galvanochemical treatments, considerable surface porosity of chalcopyrite was responsible for accelerated leaching. Also, in mechanical treatments, removing the remained passive layer from the chalcopyrite surface improved leaching. SEM results showed extensive porosity in the chalcopyrite surface in the presence of pyrite and sodium chloride and even more porosity in the presence of their combination. SEM results also showed obviously clean surface of chalcopyrite in the presence of silica. The comparison of ORP-assisted and non-ORP-assisted experiments showed that there were 8, 5.2, 3.9 and 0.5% more copper recoveries in galvanic, chemical, galvanochemical and mechanical treatments with ORP assistance, respectively. The reason was the fewer chalcopyrite surface passivation, which caused the additives to perform better.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1228-1240
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Raman Spectra and Structural Data of the Nanocrystalline KTP $(KTiOPO_4)$ Synthesized by Pechini Method
    Autorzy:
    Malekfar, R.
    Cheraghi, A.
    Ahmadi, G.
    Khanzadeh, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1585099.pdf
    Data publikacji:
    2009-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.30.-j
    77.84.Fa
    Opis:
    Nanocrystalline KTP powders are synthesized using a modified Pechini method. The structural and lattice modes of the products are investigated via X-ray diffraction, micro Raman backscattering spectroscopy, UV/vis/NIR and FT-IR transmission spectroscopy. The Debye-Scherrer formula is used to confirm the grain sizes estimated by the scanning electron microscopy slides.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 6; 1073-1075
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Soil-line vegetation indices for corn nitrogen content prediction
    Autorzy:
    Bagheri, N.
    Ahmadi, H.
    Alavipanah, S.K.
    Omid, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/24745.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Opis:
    The soil-line vegetation indices for prediction of corn canopy nitrogen content were investigated. Results indicated that the vegetation indices applied were correlated with corn canopy nitrogen content and the wavelengths between 630-860 nm are suitable for nitrogen diagnosis. The second-order polynomial equation was the best model for nitrogen content prediction among different regression types. Analyses based on both predicted and measured data were carried out to compare the performance of existing vegetation indices.
    Źródło:
    International Agrophysics; 2012, 26, 2
    0236-8722
    Pojawia się w:
    International Agrophysics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Physical properties of psyllium seed
    Autorzy:
    Ahmadi, R.
    Kalbasi-Ashtari, A.
    Gharibzahedi, S.M.T.
    Powiązania:
    https://bibliotekanauki.pl/articles/24892.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    physical property
    psyllium
    seed
    postharvest technology
    Plantago ovata
    India
    plant cultivation
    Opis:
    Physical properties ie dimensions, volume, surface area, sphericity, true density, porosity, angle of repose, terminal velocity, static and dynamic friction coefficients on plywood, stainless steel, glass and galvanized iron sheet, force required for initiating seed rupture in horizontal and vertical orientations of psylliumseed at amoisture content of 7.2%(w.b.)were determined.
    Źródło:
    International Agrophysics; 2012, 26, 1
    0236-8722
    Pojawia się w:
    International Agrophysics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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