An improvement to seismic design of substation support structures

Mohammadi, Reza Karami,Akrami, Vahid,Nikfar, Farzad Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.6

The acceleration that the electrical equipment experiences on a structure can be several times the ground acceleration. Currently, substation support structures are being designed according to ASCE (Substation Structure Design Guide 2008), without any consideration about effects of these structures on dynamic behavior of mounted equipment. In this paper, a parametric study is implemented in order to improve seismic design of candlestick substation structures based on this design guide. To do this, dynamic amplification factor (DAF) of different candlestick support-equipment combinations is evaluated and compared to the target DAF presented in IEEE STD 693 (2006). Based on this procedure, a new criterion is developed to restrict maximum acceleration at support-equipment intersection.

Seismic mitigation of substation cable connected equipment using friction pendulum systems

Reza Karami Mohammadi,Masoud Mirtaheri,Mojtaba Salkhordeh,Erfan Mosaffa,Golsa Mahdavi,Mohammad Amin Hariri-Ardebili 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.6

Power transmission substations are susceptible to potential damage under seismic excitations. Two of the major seismic failure modes in substation supplies are: the breakage of brittle insulator, and conductor end fittings. This paper presents efficient isolation strategies for seismically strengthening of a two-item set of equipment including capacitive voltage transformer (CVT) adjacent to a Lightning Arrester (LA). Two different strategies are proposed, Case A: implementation of base isolation at the base of the CVT, while the LA is kept fixed-base, and Case B: implementation of base isolation at the base of the LA, while the CVT is kept fixed-base. Both CVT and LA are connected to each other using a cable during the dynamic excitation. The probabilistic seismic behavior is measured by Incremental Dynamic Analysis (IDA), and a series of appropriate damage states are proposed. Finally, the fragility curves are derived for both the systems. It is found that Friction Pendulum System (FPS) isolator has the potential of decreasing flexural stresses caused by intense ground motions. The research has shown that when the FPS is placed under LA, i.e. Case B (as oppose to Case A), the efficiency of the system is improved in terms of reducing the forces and stresses at the bottom of the porcelain. Several parametric studies are also performed to determine the optimum physical properties of the FPS.

Identifying Superior Rainfed Barley Genotypes in Farmers' Fields Using Participatory Varietal Selection

Reza Mohammadi,Kouresh Nader Mahmoodi,Reza Haghparast,Stefania Grando,Maryam Rahmanian,Salvatore Ceccarelli 한국작물학회 2011 Journal of crop science and biotechnology Vol.14 No.4

This study was carried out to identify superior barley genotypes for the rainfed areas of western Iran using a participatory varietal selection (PVS) approach. Three field experiments were conducted in two randomly selected farmers' fields and in one rainfed research station in the 2006 - 07 cropping season with 69 genotypes (including one local and one improved check). Several univariate and multivariate methods were used to analyze qualitative (farmers' scores) and quantitative (grain yield) data. Individual farmers'scores in each village were positively correlated, indicating that the farmers tended to discriminate genotypes in similar fashion,although the genotypes actually selected by farmers were different in the two villages. In recent years, a greater number of farmers in western Iran preferred the improved variety (Sararood-1) over the local barley (Mahali), while in this project the farmers preferred the new genotypes over the two checks. This was also verified by the quantitative data showing that the checks were outyielded by the new genotypes. Farmers were efficient in identifying the best genotypes for their specific environment, as shown by biplot analysis,indicating their competence in selection. The genotypes selected by the breeder and farmers were almost similar but some differences existed. In conclusion, PVS is a powerful way to involve farmers for selecting and testing new cultivars that are adapted to their needs, systems and environments.

Identifying Superior Rainfed Barley Genotypes in Farmers' Fields Using Participatory Varietal Selection

Mohammadi, Reza,Mahmoodi, Kouresh Nader,Haghparast, Reza,Grando, Stefania,Rahmanian, Maryam,Ceccarelli, Salvatore 한국작물학회 2011 Journal of crop science and biotechnology Vol.14 No.4

This study was carried out to identify superior barley genotypes for the rainfed areas of western Iran using a participatory varietal selection (PVS) approach. Three field experiments were conducted in two randomly selected farmers' fields and in one rainfed research station in the 2006 - 07 cropping season with 69 genotypes (including one local and one improved check). Several univariate and multivariate methods were used to analyze qualitative (farmers' scores) and quantitative (grain yield) data. Individual farmers' scores in each village were positively correlated, indicating that the farmers tended to discriminate genotypes in similar fashion, although the genotypes actually selected by farmers were different in the two villages. In recent years, a greater number of farmers in western Iran preferred the improved variety (Sararood-1) over the local barley (Mahali), while in this project the farmers preferred the new genotypes over the two checks. This was also verified by the quantitative data showing that the checks were outyielded by the new genotypes. Farmers were efficient in identifying the best genotypes for their specific environment, as shown by biplot analysis, indicating their competence in selection. The genotypes selected by the breeder and farmers were almost similar but some differences existed. In conclusion, PVS is a powerful way to involve farmers for selecting and testing new cultivars that are adapted to their needs, systems and environments.

An improvement to seismic design of substation support structures

Reza Karami Mohammadi,Vahid Akrami,Farzad Nikfar 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.6

The acceleration that the electrical equipment experiences on a structure can be several times the ground acceleration. Currently, substation support structures are being designed according to ASCE (Substation Structure Design Guide 2008), without any consideration about effects of these structures on dynamic behavior of mounted equipment. In this paper, a parametric study is implemented in order to improve seismic design of candlestick substation structures based on this design guide. To do this, dynamic amplification factor (DAF) of different candlestick support-equipment combinations is evaluated and compared to the target DAF presented in IEEE STD 693 (2006). Based on this procedure, a new criterion is developed to restrict maximum acceleration at support-equipment intersection.

The Relationship between Management bonuses with Earnings stability in Information technology and Computer listed companies on the Tehran Stock Exchange

Reza Moghani,Shaban Mohammadi Mohammadi,Hamed Esmaeilioghaz 국제융합경영학회 2016 융합경영연구 Vol.4 No.4

The purpose of the present study is to investigate the relationship between Management bonuses and earnings stability of the listed companies on the Tehran Stock Exchange (TSE). The population includes 94 firms selected through systematic sampling. The data is collected from the audited financial statements of the firms provided by TSE’s website from 2009 to 2016. The results of multiple linear regression analysis show that there is a significant relationship between Management bonuses and earnings stability. The aim of this study primarily investigating the relationship between earnings stability and management bonus. In the case of this target, the next goal of this research is to develop a proposal for legislation in the domain of capital market, students and faculty as well as accounting information users provide research interests. Observations show many companies despite the decline in profitability, bonus managers to continually pay. Increase in listed companies Stock Exchange as well as the importance of communication between earnings quality and bonus managers in Financial Accounting the authors created an incentive to research about this relationship do. The results of this research could be the development of literature done in the past. Thus, more knowledge about the issue of sustainability and its relation to bonus managers the users of accounting information, accounting courses provide students and faculty.

Weed control in irrigated corn by hairy vetch interseeded at different rates and times

Mohammadi, Gholam Reza The Korean Society of Weed Science and The Turfgra 2010 Weed Biology and Management Vol.10 No.1

In order to study the potential of interseeded hairy vetch as a living mulch to control weeds in corn, a field study was conducted at the Agricultural Research Farm, Razi University, Kermanshah, Iran. The experiment was carried out in a split-split plot arrangement with four replications. The main plots were two weed treatments (weedy and weed-free for all of the growing season), the subplots were two hairy vetch planting dates (simultaneous with corn planting and 10 days after corn emergence), and the sub-subplots were three hairy vetch planting rates (0, 25, and 50 $kg\;ha^{-1}$).The results indicated that the weedy condition for all of the growing season reduced corn plant traits, including the seed yield, number of ears per plant, number of seeds per ear, 100-seed weight, height, Leaf Area Index, and leaf chlorophyll content, as compared to the weed-free condition for the entire growing season. The hairy vetch dry weight also was reduced by the full-season weedy condition. The traits under study were not significantly influenced by the hairy vetch planting times, but increasing the hairy vetch planting rate from 0 to 50 $kg\;ha^{-1}$ improved the corn yield, number of seeds per ear, 100-seed weight, height, Leaf Area Index, and leaf chlorophyll content. However, the number of ears per plant was not significantly influenced and the weed dry weight was reduced by half. Overall, from the standpoint of corn seed production, an interseeding amount of 25 $kg\;ha^{-1}$ of hairy vetch is recommended; taking into consideration the legume forage yield, an interseeding amount of 50 $kg\;ha^{-1}$ of hairy vetch is more beneficial.

Genotype x Environment Interaction for Durum Wheat Grain Yield and Selection for Drought Tolerance in Irrigated and Droughted Environments in Iran

Reza Mohammadi,Ahmed Amri 한국작물학회 2011 Journal of crop science and biotechnology Vol.14 No.4

Durum wheat is grown in the Mediterranean region under stressful and variable environmental conditions. In a 4-year-long experiment,14 genotypes [including 11 durum breeding lines, two durum (Zardak) and bread (Sardari) wheat landraces, and one durum (Saji) newly released variety] were evaluated under rainfed and irrigated conditions in Iran. Several selection indices [i.e. stress tolerance index (STI), drought tolerance efficiency (DTE), and irrigation efficiency (IE)] were used to characterize genotypic differences in response to drought. The GGE biplot methodology was applied to analyze a three-way genotype-environment-trait data. Combined ANOVA showed that the year effect was a predominant source of variation. The genotypes differed significantly (P < 0.01) in grain yield in the both rainfed and irrigated conditions. Graphic analysis of the relationship among the selection indices indicated that they are not correlated in ranking of genotypes. The two wheat landraces and the durum-improved variety with high DTE had minimum yield reduction under drought-stressed environments. According to STI, which combines yield potential and drought tolerance, the "Saji" cultivar followed by some breeding lines (G11, G8, and G4) performed better than the two landraces and were found to be stable and high-yielding genotypes in drought-prone rainfed environments. The breeding lines G8, G6, G4, and G9 were the efficient genotypes responding to irrigation utilization. In conclusion, the identification of the durum genotypes (G12, G11, and G4) with high yield and stability performance under unpredictable environments and high tolerance to drought stress conditions can help breeding programs and eventually contribute to increasing and sustainability of durum production in the unpredictable conditions of Iran.

Influence of commercial culture composition and cow milk to soy milk ratio on the biochemical, microbiological, and sensory characteristics of a probiotic fermented composite drink

Reza Mohammadi,Mojtaba Yousefi,Zahra Sarlak,Nagendra Prasad Shah,Amir Mohammad Mortazavian,Ehsan Sadeghi,Maryam Zabihzadeh Khajavi 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.3

In this study, the effects of various ratios of cow milk to soy milk (100:0, 75:25, 50:50, 25:75, and 0:100) and three types of commercial culture composition (ABY- 1, MY-720, and YO-Mix 210; all of them containing Lactobacillus acidophilus, Bifidobacterium lactis, and yogurt cultures) on the biochemical, microbiological, and sensory characteristics of a probiotic fermented composite drink during incubation and refrigerated storage were investigated. It was found that the shortest fermentation time, greatest mean pH drop rate, and mean acidity increase rate were related to the 50:50/ABY treatment. 25:75/ABY and 25:75/MY treatments exhibited the highest viability of B. bifidum and/or L. acidophilus at the end of 21 days of refrigerated storage. The influence of the type of starter culture composition on the sensory properties of the final products was not significant. Based on microbial and sensory evaluations, using the 50:50 ratio with each type of culture composition was considered as the most suitable treatment.

Analysis of Genotype-by-Environment Interaction for Grain Yield of Rainfed Durum Wheat Genotypes in Warm Winter Areas of Iran

Reza Mohammadi,Mohtasham Mohammadi,Rahmatollah Karimizadeh,Ahmed Amri 한국작물학회 2010 Journal of crop science and biotechnology Vol.13 No.4

This study was performed for pattern analysis of genotype-by-environment (GE) interaction on 20 durum wheat genotypes grown in 15 testing environments during 2004 - 06 in Iran. Combined analysis of variance showed significant genotypes (G), environments (E), and GE interactions (P < 0.01), with environmental main effects being the predominant source of variation, followed by GE interaction. The results showed various patterns of genotype responses to different environment groups and assisted in structuring the durum wheat testing locations with identification of two major-environment groups with high genotype discrimination ability. The locations (Gachsaran and Ilam) corresponding to warm and semi-arid aresa were similar in genotype discrimination and showed no association with the other testing locations (Gonbad, Moghan, and Khoramabad) representing the Mediterranean area, indicating they differ in rankings of genotypes. The top-yielding genotypes, G13, G14 and G9, were highly adapted to warm and semi-arid environments,but those corresponding to the Mediterranean area had a high ability to discriminate the genotypes G16, G11, and Saimareh. The stability and adaptability of specific genotypes were assessed by plotting their nominal grain yields at specific environments in an ordination biplot, which aided in the identification of environment groups. Appropriate check genotypes for all environments or for specific environments were also identified. Pattern analysis allowed a sensible and useful summarization of GE interaction data set and helped to facilitate selecting superior genotypes for target-growing sites.