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


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

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