Investigating the Effect of CuO/NiO and CuO/CoO Relative Composition on the Reduction Time of (CuO)x-(NiO)(1-x) and (CuO)x-(Co3O4)(1-x) with Methane Gas as the Reducing Agent in the Synthesis of Nano-bimetallic Nix-Cu(1-x) and Cux-Co(1-x)

In this paper, the reduction duration of (CuO)x-(NiO)(1-x) and (CuO)x-(Co3O4)(1-x) binary mixtures was studied using thermogravimetric method. The reduction reaction was performed using copper, nickel and cobalt oxides as metal precursors and methane gas as the reducing agent, under atmospheric pressure. The products as well as the raw materials were characterized and analyzed using X-Ray diffraction (XRD) and Energy Dispersive Spectroscopy (EDS). Initially, CoO, NiO and CuO were transformed to Co, Ni and Cu through reduction reactions with 23 Vol.% of methane at 830 °C. Results demonstrated that the reduction times of NiO, CoO and CuO NPs with CH4 at 830 °C were 14, 39 and 47 min, respectively. EDS and XRD analysis indicated that more than 97 % of copper, nickel and cobalt oxides were transformed to copper, nickel and cobalt NPs. The reaction time of (CuO)x-(NiO)(1-x) and (CuO)x-(Co3O4)(1-x) binary mixtures with methane was investigated to evaluate the effect of CuO (x=0, 0.4, 0.6, 1) relative composition. In addition, the reaction time of ternary mixture of (NiO)0.6-(CuO)0.2-(Co3O4)0.2 with methane gas was also studied

Effect of BA and Ovule Developmental Stages on Embryo Rescue in Perlette Grape (Vitis Vinifera L.) Cultivar

Production of seedless varieties is one of the major breeding goals in grape vine. Traditional methods result in low percentage of seedless progeny production. Today for producing high percentage of seedless progeny, embryo rescue are used. In this research, the effects of BA concentrations (0, 30, 60 and 100 mg L-1) and the stage of ovule development (25, 35, 45, 55 and 65 days after pollination) were assessed on the success rate of the embryo rescue in Perlette grape (Vitis vinifera L.). BA was sprayed 14 days before and 7days after the anthesis. The berries were harvested at 25, 35, 45, 55 and 65 days post pollination. Ovules were cultured  in Nitch and Nitch medium with 0.35 mg L-1gibberellic acid (GA3) and 1 mg L-1 indolacetic acid (IAA). Characters such as germination, collapsed, callus-formed and enlarged ovules were recorded. The results revealed the effect of BA pre-treating and ovule developmental stage on percentage of germinated embryos, collapsed, callus- formed and enlarged ovules. The highest germination percentage was observed in BA 100 mg L-1 at 65 days post pollination treatment. The highest percentage of the collapsed ovules was observed at 25 days after pollination in all treatments. The highest percentage of the callus formation was observed in the BA treatment of 30 mg L-1 at 55 days after pollination. The highest percentage of the enlarged ovules was observed in the BA treatment of 60 mg L-1 at 45 days after pollination

Efficiency assessment and managerial ability analysis of the regional electricity transmission sector with the presence of contextual variables

The electricity industry plays a pivotal role in a country's economic growth and development. Therefore, it is imperative to assess its performance and identify the strengths and weaknesses of its different sectors, such as production, transmission, and distribution, to enhance economic growth in diverse areas. Given the significance of the transmission sector, this research focuses on analyzing and evaluating the performance of 16 regional electricity companies in Iran from 1390 to 1398, with the aim of comprehending the impact of contextual variables on efficiency. To achieve this, the study will utilize two techniques - Data Envelopment Analysis (DEA) and Ordinary Least Squares (OLS) - to determine the efficiency score and estimate the effect of contextual variables on efficiency, respectively. In the first stage, the DEA technique is employed to calculate the technical efficiency of each company, considering their specific inputs and outputs. In the second stage, the logarithm of the efficiency scores obtained is regressed on contextual variables to establish their effect on efficiency. The residual derived from the regression is referred to as managerial ability. Finally, the companies are ranked based on their modified efficiency after removing the impact of contextual variables. Introduction The electricity industry comprises three key sectors: production, transmission, and distribution. It stands as one of the most crucial economic infrastructures in the country, exerting significant influence on industrial, agricultural, service, and other sectors. Undoubtedly, the growth of the electricity industry drives the nation's economic development and progress, contributing to the prosperity and comfort of its citizens (Tavassoli et al., 2020). Consequently, analyzing and examining the growth trajectory of each sector across different years becomes pivotal in mitigating adverse effects and fostering progress within this domain. In recent years, numerous researchers have conducted studies in this field. Some have independently evaluated each production, transmission, and distribution sector, while others have adopted a comprehensive approach by considering the integrated three-stage network structure. The research background highlights that the transmission sector has received less attention from researchers than other sectors. This is noteworthy because, following electricity production, the transmission process and energy accessibility to consumers are paramount. The absence of proper energy transfer can result in consumer dissatisfaction, financial losses, and stagnation within the competitive economic market. Therefore, identifying the strengths and weaknesses of the transmission sector's performance and comparing regional electricity transmission companies can effectively help enhance the performance level of each. One technique that has captured researchers' attention for evaluating the electricity industry's performance is the data envelopment analysis (DEA) technique. DEA is a non-parametric method used to assess the performance of homogeneous units, considering multiple inputs and outputs. It was initially introduced in 1978 by Charnes et al. The initial model was built upon the assumption of constant returns to scale. Subsequently, Banker et al. (1984) extended it by presenting a model under the assumption of returns to a variable scale. Importantly, traditional DEA models evaluate a system's performance based on specific inputs and outputs consumed and produced by the unit. However, various factors, such as contextual variables, managerial ability, and skill, can significantly influence performance and productivity. A crucial point to consider is that managerial abilities are not always overtly visible. This lack of direct visibility can impede accurate measurement. Hence, recognizing these variables among the existing indicators and assessing their influence on the performance and efficiency of each unit holds particular significance. This procedure enhances the precision of evaluation and opens avenues for delivering enhanced solutions aimed at improving the system's overall performance. Methodology The objective of this study is to analyze and evaluate the performance of Iran's regional electricity transmission sector while considering contextual variables and establishing a ranking methodology based on managerial ability. This perspective enables the identification of strengths and weaknesses in the system's structure from various angles and offers appropriate solutions for enhancement. To accomplish this, the first step involves identifying all variables within the transmission section, encompassing inputs, outputs, and contextual factors. Subsequently, we determine the technical efficiency of each regional power transmission company, taking into account specific inputs and outputs, using meta-frontier technology. The concept of meta-frontier in DEA measures the gap or distance between decision-making units (DMUs) across different boundaries. This approach assumes a unified boundary for all subgroups, enabling efficiency estimation based on a single boundary (Battese, 2004; O'Donnell, 2008). Its primary advantage lies in resolving the challenge of evaluating efficiency at varying levels. As a result, meta-frontier technology enhances the precision of evaluating regional power companies over multiple periods. After assessing the efficiency of each regional electricity transmission company, we employ the linear regression method to estimate the impact of contextual variables on efficiency, subsequently yielding a measure of managerial ability. Ultimately, we introduce a method for ranking each company based on managerial ability. The advantage of the proposed method is that, in addition to reviewing and analyzing the technical efficiency of each of the companies in the regional electricity transmission sector during different periods, it will be possible to evaluate the managerial ability of each of the companies. Such a perspective allows for companies to be compared from different dimensions. Moreover, providing a new ranking criterion based on managerial ability also facilitates a better and more accurate comparison. Results In this study, the performance of Iran's regional power companies was analyzed and evaluated from two systems and management perspectives during the years 1390-1398. Additionally, a new rating criterion based on managerial ability was presented to compare the performance of companies during 9 time periods. In this regard, firstly, the technical efficiency of 16 regional electricity companies during 9 time periods was calculated based on the inputs of the number of employees and receiving energy from neighboring companies and the outputs of sending energy to neighboring companies and delivering energy to distribution companies, using meta-frontier technology and the DEA approach. Then, the effect of contextual variables, such as line length, transformer capacity, and loss magnitude, on the efficiency score of each company was estimated using the ordinary least squares method (OLS). Furthermore, the managerial ability of each company was determined during different periods. Ultimately, a ranking criterion was established based on the results of technical efficiency after removing the effect of contextual variables. Conclusion The results of efficiency measurements over 9 time periods indicate that the highest and lowest average efficiencies were observed in the years 1390 and 1398, respectively. Furthermore, it's evident that, in general, the performance of Iran's 16 regional electricity companies exhibited a consistent upward trend from 1390 to 1398. Among the 16 evaluated companies, the Guilan regional electricity company consistently achieved the highest level of efficiency across all 9 time periods, reflecting its strong performance. Conversely, the Fars regional electricity company consistently had the lowest efficiency, indicating its weaker performance compared to other companies. When analyzing the companies' performance by year, it's noteworthy that the Tehran regional electricity company secured the highest rank in 1390, 1391, and 1394, while the Fars regional electricity company held the top spot in the remaining years. In contrast, the Sistan regional electricity company consistently displayed the lowest performance throughout all periods. The assessment of management performance over the 9 time periods indicates that the Kerman regional electricity company demonstrated superior performance from 1390 to 1393, whereas the Guilan regional electricity company excelled from 1394 to 1398, outperforming other companies. Conversely, the Gharb regional electricity company exhibited weaker performance compared to its counterparts. Additionally, the results of the regression analysis highlight a positive relationship between the efficiency score and two variables: line length and transformer capacity. Conversely, the relationship with loss magnitude is observed to be inversely correlated

Propolis and its constituents against cardiovascular risk factors including obesity, hypertension, atherosclerosis, diabetes, and dyslipidemia: A comprehensive review

Cardiovascular diseases (CVDs) are some of the major causes of death worldwide. The modern lifestyle elevates the risk of CVDs. CVDs have several risk factors such as obesity, dyslipidemia, atherosclerosis, hypertension, and diabetes. Using herbal and natural products plays a pivotal role in the treatment of different diseases such as CVDs, diabetes, and metabolic syndrome. Propolis, a natural resinous mixture, is made by honey bees. Its main components are phenolics and terpenoid compounds such as caffeic acid phenethyl ester, chrysin, and quercetin. In this review, multiple studies regarding the pharmacological impacts of propolis and its constituents with their related mechanisms of action against mentioned CVD risk factors have been discussed in detail. Here, we used electronic databases or search engines such as Scopus, Web of Science, Pubmed, and Google Scholar without time limitations. The primary components of propolis are phenolics and terpenoid compounds such as caffeic acid phenethyl ester, chrysin and quercetin. Propolis and its constituents have been found to exhibit anti-obesity, anti-hypertension, anti-dyslipidemic, anti-atherosclerosis, and anti-diabetic effects. The vast majority of studies discussed in this review demonstrate that propolis and its constituents could have therapeutic effects against mentioned CVD risk factors via several mechanisms such as antioxidant, anti-inflammatory, reducing adipogenesis, HMG-CoA reductase inhibitory effect, inhibition of the ACE, increasing insulin secretion, NO level, etc

Carbon nanotube synthesis via the catalytic chemical vapor deposition of methane in the presence of iron, molybdenum, and iron–molybdenum alloy thin layer catalysts

In this study, we documented the catalytic chemical vapor deposition synthesis of carbon nanotubes (CNTs) using ferrocene and molybdenum hexacarbonyl as catalyst nanoparticle precursors and methane as a nontoxic and economical carbon source for the first time. Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, wavelength dispersive X-ray spectrometry and transmission electron microscopy of the thin layer catalyst as a simple and cost effective catalyst preparation after methane decomposition reaction, along with Fourier transform infrared spectroscopy and Raman spectroscopy confirmed the growth of CNTs, from bimetallic nanoparticles, which are converted into iron–molybdenum alloy nanoparticles at 700 °C for pretreatment by hydrogen after chemical vapor deposition of thin layers. An investigation of the weight percentages of the chemical elements present in the CNTs synthesized from iron–molybdenum catalyst using quartz sheet substrate at 750 °C, confirmed a significant carbon yield of 75.4% which represents high catalyst activity. Additionally, multi-walled carbon nanotubes (∼16–55 nm in diameter and 1.2 µm in length) were observed in the iron–molybdenum alloy sample after methane decomposition reaction at 750 °C for 35 min. To show the role of iron and molybdenum coated on silicon substrate as two thin layer catalysts, samples were considered for CNTs growth (diameter ∼47–69 nm) at 800 °C and 830 °C, respectively. Moreover, the effect of hydrogen pretreatment was evaluated in terms of active metal coating properly. The best graphitic structure due to Raman spectroscopy outcomes (ID/IG ratio) was obtained for iron coated on a quartz sheet, which was estimated at 0.8505. Thermogravimetric analysis proved the thermal stability of the synthesized CNTs using iron thin-layer catalyst up to 350 °C. Keywords: Methane decomposition reaction, Chemical vapor deposition, Carbon nanotubes, Thin layer, Iron–molybdenum alloy catalys

A Data Envelopment Analysis Approach to Supply Chain Efficiency

Supply chain management is an important competitive strategies used by modern enterprises. Effective design and management of supply chains assists in the production and delivery of a variety of products at low costs, high quality, and short lead times. Recently, data envelopment analysis (DEA) has been extended to examine the efficiency of supply chain operations. Due to the existence of intermediate measures, the usual procedure of adjusting the inputs or outputs, as in the standard DEA approach, does not necessarily yield a frontier projection. The current paper develops a DEA model for measuring the performance of suppliers and manufacturers in supply chain operations. Additive efficiency decomposition for suppliers and manufacturers in supply chain operations is proposed

Evaluation of Ability of Hydrogen Absorption in SAB-16/Pd Nanostructure Composite

The purpose of this work was to study the hydrogen adsorption on the surface of mesoporous materials based on silica (SBA-16) modified with palladium via temperature. Since mesoporous silica materials have a high specific surface area, and the ordered mesoporous size of 2-10nm, they are suitable for adsorption and storage of hydrogen. SBA-16 is suitable for this purpose due to its cubic crystalstructure and open pores. Single-stage sol-gel method was used to produce nanostructure composite from salt of palladium (PdCl3) and mesoporous silica precursor. The aging time was selected as 12 hr at 80˚C. Furthermore, the obtained materials were heated at 550˚C for 6 hr to remove surfactant and to form pores. Then the materials were characterized by large angle and small angle x-ray diffraction analysis, and hydrogen absorption analysis at upto 200kPa pressure at three different temperatures of -196˚C (77 K), -123˚C (150 K) and 30˚C (303 K). Furthermore, adsorption-desorption of nitrogen gas was studied. The surface morphology was observed by field emission scanning electron microscope (FESEM). In addition, the amount of palladium, oxygen, and silicon were measured by using energy dispersive spectroscopy) EDS ). Finally, the functional groups on the surface of mesoporous silica materials were evaluated using Fourier transform infrared spectroscopy (FTIR). The results of XRD and EDS analyses confirmed the presence of palladium and palladium oxide in mesoporous amorphous silica. In addition, BET results showed that addition of palladium in SBA-16 decreased the surface area, and produced 791 and 538m2/g for SBA-16 and SBA-16/Pd, respectively. Hydrogen absorption in nano structure composite was decreasing with temperatur in comparison with SAB-16. On the other hand, the maximum hydrogen absorption in the nano structure composite containing palladium was obtained at -196˚C (77 K)