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Strongly Clean Matrix Rings over a Skew Monoid Ring

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Algebra Colloquium 2023年第3期30卷 361-370页

作者： Arezou Karimimansoub mohammad-Reza(Rafsanjani)sadeghi Department of Mathematics and Computer Science Amirkabir University of TechnologyTehranP.O.Box ***Iran

Let R be a ring with an endomorphismσ,F∪{0}the free monoid generated by U={u1,…,ut}with 0 added,and M a factor of F obtained by setting certain monomials in F to 0 such that M^(n)=0 for some *** we can form the non-semiprime skew monoid ring R[M;σ].A local ring R is called bleached if for any j∈J(R)and any u∈U(R),the abelian group endomorphisms l_(u)−r_(j) and l_(j)−r_(u) of R are *** R[M;σ],we provide various classes of both bleached and non-bleached local *** of the main problems concerning strongly clean rings is to characterize the rings R for which the matrix ring M_(n)(R)is strongly *** investigate the strong cleanness of the full matrix rings over the skew monoid ring R[M;σ].

关键词： skew monoid rings strongly clean rings matrix rings

Effects of operating parameters on oxidative coupling of methane over Na-W-Mn/SiO_2 catalyst at elevated pressures

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Journal of Natural Gas Chemistry 2011年第2期20卷 204-213页

作者： Jafar Sadeghzadeh Ahari mohammad Taghi sadeghi Saeed Zarrinpashne Process Simulation and Control Laboratory Chemical Engineering College Iran University of Science and Technology (IUST) Gas Research Division-Research Institute of Petroleum Industry (RIPI)

The effects of operating parameters on oxidative coupling of methane （OCM） over Na-W-Mn/SiO2 catalyst have been studied at elevated pressures of 0.2, 0.3 and 0.4 MPa under low gaseous hourly space velocity （GHSV） and low temperature conditions. Experimental results show that when the operating pressure is increased, C2＋ yield slightly decreases, while the maximum ratio of ethylene to ethane remains unchanged. Moreover, it has been found empirically that increase of pressure does not affect the catalyst behavior permanently, the catalyst recovers its original low pressure performance without hysteresis behavior by reducing the pressure. Under the investigated conditions, when oxygen is completely consumed, the increase of GHSV leads to improvement in C2 selectivity, while C3＋ and COx selectivities decrease slightly. The C2＋ selectivity increases by increase of nitrogen diluent in the feed, but the C3＋ hydrocarbons selectivities decrease with increase of nitrogen since it is possible that further dilution at high pressure may reduce the probability of collision between CH3 and C2＋ hydrocarbons. During the stability test at high pressure, the catalyst performance remains unchanged throughout the 20 h running. The fresh and used catalysts were characterized using XRD, SEM and N2 adsorption-desorption methods. It was found that the phase transformation of the support from α-cristobalite to tridymite and quartz does not have obvious effect on catalyst performance at high pressure.

关键词： operating parameters oxidative coupling of methane Na-W-Mn/SiO2 catalyst elevated pressure

Perfect field concentrator using zero index metamaterials and perfect electric conductors

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Frontiers of physics 2014年第1期9卷 90-93页

作者： mohammad Mehdi sadeghi Hamid Nadgaran Huanyang Chen School of Physical Science and Technology Soochow University Suzhou 215006 China Department of Physics Shiraz University Shiraz 71454 Iran

We design a perfect field concentrator from a singular radial mapping. Such a device can be implemented using alternating radial slices of zero index metamaterials and perfect electric conductors. Numerical simulation... 详细信息

关键词： field concentrator transformation optics zero index metamaterials perfect electricconductors

Soft sensor design for hydrodesulfurization process using support vector regression based on WT and PCA

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Journal of Central South University 2015年第2期22卷 511-521页

作者： Saeid Shokri mohammad Taghi sadeghi Mahdi Ahmadi Marvast Shankar Narasimhan Department of Chemical Engineering Iran University of Science and Technology (IUST) Tehran 16765?163 Iran Process & Equipment Technology Development Division Research Institute of Petroleum Industry (RIPI) Tehran 14665?137 Iran Department of Chemical Engineering IIT Madras Chennai 600036 India

A novel method for developing a reliable data driven soft sensor to improve the prediction accuracy of sulfur content in hydrodesulfurization(HDS) process was proposed. Therefore, an integrated approach using support vector regression(SVR) based on wavelet transform(WT) and principal component analysis(PCA) was used. Experimental data from the HDS setup were employed to validate the proposed model. The results reveal that the integrated WT-PCA with SVR model was able to increase the prediction accuracy of SVR model. Implementation of the proposed model delivers the best satisfactory predicting performance(EAARE=0.058 and R2=0.97) in comparison with SVR. The obtained results indicate that the proposed model is more reliable and more precise than the multiple linear regression(MLR), SVR and PCA-SVR.

关键词： soft sensor support vector regression principal component analysis wavelet transform hydrodesulfurization process

Improvement of the prediction performance of a soft sensor model based on support vector regression for production of ultra-low sulfur diesel

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Petroleum Science 2015年第1期12卷 177-188页

作者： Saeid Shokri mohammad Taghi sadeghi Mahdi Ahmadi Marvast Shankar Narasimhan Department of Chemical Engineering Iran University of Science and Technology (IUST) Process and Equipment Technology Development Division Research Institute of Petroleum Industry (RIPI) Department of Chemical Engineering

A novel data-driven, soft sensor based on support vector regression （SVR） integrated with a data compression technique was developed to predict the product quality for the hydrodesulfurization （HDS） process. A wide range of experimental data was taken from a HDS setup to train and test the SVR model. Hyper-parameter tuning is one of the main challenges to improve predictive accuracy of the SVR model. Therefore, a hybrid approach using a combination of genetic algorithm （GA） and sequential quadratic programming （SQP） methods （GA-SQP） was developed. Performance of different optimization algorithms including GA-SQP, GA, pattern search （PS）, and grid search （GS） indicated that the best average absolute relative error （AARE）, squared correlation coefficient （R2）, and computation time （CT）（AARE = 0.0745, R2 = 0.997 and CT = 56 s） was accomplished by the hybrid algorithm. Moreover, to reduce the CT and improve the accuracy of the SVR model, the vector quantization （VQ） technique was used. The results also showed that the VQ technique can decrease the training time and improve prediction performance of the SVR model. The proposed method can provide a robust, soft sensor in a wide range of sulfur contents with good accuracy.

关键词： Soft sensor Support vector regression Hybrid optimization method Vector quantization Petroleum refinery Hydrodesulfurization process Gas oil

Pectin-Based Biodegradable Hydrogels with Potential Biomedical Applications as Drug Delivery Systems

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Journal of Biomaterials and Nanobiotechnology 2011年第1期2卷 36-40页

作者： mohammad sadeghi 不详

In this work, synthesis and swelling behavior of a superabsorbent hydrogel based on Pectin (Pc) and polyacrylonitrile (PAN) were investigated. A mechanism for hydrogel formation was proposed and the structure of the product was es-tablished using FTIR spectroscopy. The Pc-poly (sodium acrylate-co-acrylamide) hydrogel exhibited a pH-responsive swelling-deswelling behavior at pH’s 2 and 8. This on-off switching behavior provides the hydrogel with the potential to control delivery of bioactive agents. Release profiles of ibuprofen (IBU), a poor water-soluble drug, from the hydro-gels were studied under both simulated gastric and intestinal pH conditions.

关键词： Pectin Polyacrylonitrile Hydrogel Ibuprofen Drug Delivery

Enhanced Sensitivity and Stability in Gelatin-Based Fricke gel Dosimeters:Impact of Benzoic Acid on Low-Dose Radiation Measurements

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Instrumentation 2024年第3期11卷 23-29页

作者： Seyed Amir Saeedi-Sini Sedigheh Sina mohammad Hossein sadeghi Ebrahim Farajzadeh Nuclear Engineering Department School of Mechanical EngineeringShiraz UniversityShirazIran Radiation Research Center School of Mechanical EngineeringShiraz UniversityShirazIran Secondary Standard Dosimetry Laboratory(SSDL) Pars Isotope Co.KarajIran

Fricke gel dosimetry is a critical technique for accurate radiation dose measurement, leveraging the radiation-induced oxidation of ferrous to ferric ions within a hydrogel matrix. This study aimed to advance the field by preparing and evaluating seventy-one Fricke gel dosimeter(FGD) samples with varying chemical compositions, focusing on the incorporation of benzoic acid. Two gelatin-based samples demonstrated superior sensitivity, particularly for low-dose measurements. Our findings indicated that the sample without benzoic acid exhibited a 1.75 times higher sensitivity compared to the sample containing benzoic acid, with lower limits of detection at 0.04 Gy and 0.1 Gy, respectively. Stability tests revealed temperature-dependent responses, with better performance observed under refrigerated conditions. Reproducibility was confirmed through consistent calibration curves across multiple trials. Additionally, the dosimeters' responses varied with different radiation types, underscoring the need for specific calibrations. The study concludes that while benzoic acid slightly reduces sensitivity, it provides consistent responses across various radiation energies, suggesting its potential as a beneficial additive in diverse clinical scenarios. This research contributes to the ongoing optimization of FGDs for precise radiation dose assessment.

关键词： chemical dosimeter freak dosimeter benzoic acid

Using ELECTRE-TRI and FlowSort methods in a stock portfolio selection context

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Financial Innovation 2022年第1期8卷 331-365页

作者： Mir Seyed mohammad Mohsen Emamat Caroline Maria de Miranda Mota mohammad Reza Mehregan mohammad Reza sadeghi Moghadam Philippe Nemery Department of Industrial Management Faculty of Management and AccountingAllameh Tabataba’i UniversityTehran 14348-63111Iran Universidade Federal de Pernambuco RecifeBrazil University of Tehran TehranIran SAP BeLux BrusselsBelgium

In recent years,multi-criteria sorting problems have become an interesting topic for researchers working on multi-criteria *** and Choice Expressing REality(ELECTRE)-TRI and FlowSort are well-known approaches suggested for such a *** current study aimed to implement ELECTRE-TRI and FlowSort methods in the stock portfolio selection(SPS)as one of the most popular and important decision-making subjects and compare the outcomes of each method to understand how these methods perform in SPS *** this study,the best–worst method was applied to determine the weights of *** approaches for ELECTRE-TRI and 15 approaches for FlowSort were ***,19 different approaches were considered to select stocks from a large pool of *** indicated that the model parameter should be properly defined to minimize inconsistencies and improve the power of the model.

关键词： Multi-criteria decision-making ELECTRE-TRI FlowSort Best-worst method Finance

Temperature-, and pH-Responsiveness Properties of a Biopolymer Based on kC-g-poly （AA-co-NIPAM）

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Journal of Chemistry and Chemical Engineering 2011年第6期5卷 569-575页

作者： mohammad sadeghi Mojgan Yarahmadi Department of Chemistry Science Faculty Islamic Azad University Arak Branch Arak Iran Department of English Islamic Azad University Arak Branch Arak 38135-567 Arak Iran

A novel thermo-sensitive superabsorbent hydrogel with salt- and pH-responsiveness properties was obtained by grafting of mixtures of acrylic acid （AA） and N-isopropylacrylamide （N1PAM） monomers onto kappa-carrageenan, kC, using ammonium persulfate （APS） as a free radical initiator in the presence of methylene bisacrylamide （MBA） as a crosslinker. Infrared spectroscopy was carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy （SEM）. The effect of MBA concentration and AA/NIPAM weight ratio on the water absorbency capacity has been investigated. The swelling variations of hydrogels were explained according to swelling theory based on the hydrogel chemical structure. The hydrogels exhibited salt-sensitivity and cation exchange properties. The temperature- and pH-reversibility properties of the hydrogels make the intelligent polymers as good candidates for considering as potential carriers for bioactive agents, e.g. drugs.

关键词： Superabsorbent carrageenan acrylic acid N-isopropylacrylamide hydrogel swelling.