78 research outputs found

    Effect of Turbocharger Compression Ratio on Performance of the Spark-Ignition Internal Combustion Engine

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    Internal Combustion Engines (ICE) are one of the most important engineering applications that operate based on the conversion of chemical energy from fuel into thermal energy as a result of direct combustion. The obtained thermal energy is then turned into kinetic energy to derive various means of transportation, such as marine, air, and land vehicles. The efficiency of ICE today is considered in the range of the intermediate level, and various improvements are being made to enhance its efficiency. The turbocharger can support the ICE, which works by increasing the pressure in the engine to enhance its efficiency. In this investigation, the effect of the turbocharger pressure on ICE performance was studied in the range of 2 to 10 bar. It was found that the increase in turbocharger pressure enhanced the pressure inside the engine, positively affecting engine efficiency indicators. Therefore, the increase in turbocharger pressure is directly proportional to the ICE efficiency. Doi: 10.28991/ESJ-2022-06-03-04 Full Text: PD

    An explanatory model of depression among female patients in Fars, Kurds, Turks ethnic groups of Iran

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    Background: Depressive disorder is globally estimated to be as many as one in five visits to primary health care. Approximately more than 50 of depressed women in primary care are not diagnosed. As a part of a major investigation into perceptions of women's depression, this study explored how female patients and their relatives conceptualize patients' conditions in three ethnic groups in Iran (Fars, Kurds and Turks). Methods: Qualitative methods were used for data collection. Depressed women and their relatives were purposively selected from the public psychiatric clinics affiliated to university of medical sciences in the three study cities. Twentyfive depressed women and 14 relatives were interviewed in three ethnic groups. Results: One theme "illness meaning", including three categories: perceived symptoms, label of the illness, and effects of the illness was found through the content analysis. The participants perceived symptoms of illness as somatic and psychological depending on the participant's assumed reason for the onset of the illness. There were most similarities in term used for of the illness in the three ethnic groups. Most of the study participants described the illness in terms of nerve problems/illness, and depression "afsordehgi". The most important effects that depressed women had experienced because of their illness were marital conflict or a guilt feeling originating from their inability to support family. Conclusion: These findings suggest the need to recognize and choose appropriate diagnostic approach for depressed women in the context of Iran

    First direct measurement of resonance strengths in 17O({\alpha}, {\gamma})21Ne

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    The reaction 17O({\alpha},{\gamma})21Ne has been measured by in-beam gamma spectroscopy for the first time in the energy range E{\alpha} = 750 keV to 1650 keV using highly enriched anodized Ta2(17O)5 targets. Resonances were found at E({\alpha}) = 1002 keV, 1386 keV and 1619 keV. Their strengths and primary gamma-ray branchings are given. The new results exclude the low reaction rate of Descouvemont and support the rate of Caughlan and Fowler. Implications for the neutron poisoning efficiency of 16O in the weak s process are discussed.Comment: 5 pages, 5 figures, 2 tables, Accepted for publication in Phys. Rev.

    Constraining the S factor of 15N(p,g)16O at Astrophysical Energies

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    The 15N(p,g)16O reaction represents a break out reaction linking the first and second cycle of the CNO cycles redistributing the carbon and nitrogen abundances into the oxygen range. The reaction is dominated by two broad resonances at Ep = 338 keV and 1028 keV and a Direct Capture contribution to the ground state of 16O. Interference effects between these contributions in both the low energy region (Ep < 338 keV) and in between the two resonances (338 <Ep < 1028 keV) can dramatically effect the extrapolation to energies of astrophysical interest. To facilitate a reliable extrapolation the 15N(p,g)16O reaction has been remeasured covering the energy range from Ep=1800 keV down to 130 keV. The results have been analyzed in the framework of a multi-level R-matrix theory and a S(0) value of 39.6 keV b has been found.Comment: 15 pages, 9 figure

    Induction of population triploid-interploid in rainbow trout (Oncorhynchus mikiss) using by indirect

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    Induced polyploidy is a suitable tool for producing sterile fish which made commercial benefits in the aquaculture industry. This study carried out in order to produce triploid-interploid population via mating tetraploid female with diploid male rainbow trout. Heat shock was used for making tetraploid population and the best temperature and induction time were examined. Result showed that highest mortality from 1 day after fertilization to emerging were in groups 6 of embryos (40.1%) and the lowest were in groups 3 (33 %). Flowcytometry results showed that some fish were polyploidy. Comparative analyze of genome levels in tetraploid fish to control fish (diploid) and hen as standard indicator, confirmed tetraploid fishes in this study. In conclusion we can state that heat shock induction for 7 minutes at 65 hour –degree after fertilization in 28ºC is optimum temperature for inducting tetraploid rainbow trout

    Investigation of chromosome and ploidy levels of rainbow trout produced from imported eyed eggs

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    Rainbow trout is the main cultural species of coldwater fishes in iran. Often, aquaculturists intend to breeding in order to production of lines with higher growth rate potential and disease resistant. Nevertheless in the country, no trout breeding programs, has been performed yet and most of the farms focused on the cultivation of the first (unbred) race. While European countries progressed in trout breeding techniques and production lines with higher growth through genetic manipulation (chromosomal number and type changes of fish) and/or selection and their fish products derived from this technology, including eyed eggs and so on have sold to other regions of the world (eg: Iran). In this study, some biological parameters including survival, growth, feed conversion ratio (FCR.) and chromosomal number of two juvenile groups from imported( group 1) and native(group 2) eyed fish eggs were compared. For chromosomal investigation, blood smear test and flow cytometry were performed. sults showed a significant difference (P≤5%) in growth rate of native fishes and French group Native fish feed conversion ratio (0.9) was significantly difference (P≤5%) from that of French fishes (1.15). Chromosomal analysis showed no difference in chromosome number in treatments and two fish groups were 2n chromosome. Based on the results, the fishes of group 1 had faster grow potential and gain weight in less time than that of group 2 and this has been achieved to go through the process of selection and feminization without any change in number of ploidy. Whereas the ability of native fishes in food efficiency ( lower FCR.) was better. However, the reduction of rearing period is the benefit and preference of cultivation of imported or origionally foreign

    Genetic improvement of rainbow trout in Iran

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    Inthisstudy, Iranian and French male and female Oncorhynchus mykiss broodstocks were invided into two groups 50 and 24 respectivelyin Research center of genetic and breeding of coldwater fishers, Yasouj,Iran and the genetic structure of them was investigated using 6 microsatellite markers. Along with broodstock maturation, fertilization 1:1(female:male) were randomly assigned and occurred in25 of12Iranian andFrench treatment respectively. Reproductive parameters were recordedfor the whole family.Average number of observed alleles in Iranian and French stocks was 6.68 and 6.83, respectively.Average number of effective alleles in Iranian and French stocks was 3.13 and 3.45 respectively.Fixation index Fstwas calculated based on allelic frequency between two stocks was 0.058 with significant difference between 2 stocks. Eyed percentage for french broodstock calaulated zero and deleted. Fertilization rate(100-0), the eyed percentage (98-0), The hatch rate(98- 0),the averagefecundity4114.708, the average eggs size 4.88 mm, Survivalinthe first three months 19-73% calculated for Iranian broodstocks. Considering the quality of eggs and larvaeat different stages and selection between the different family and the within family remained 10 treatments and are keptas future broodstocks. Therelationship between fecundity-egg size, fecundity-weight, fecundity-length, egg sizeweightwas performed using regression. The results showed that Fecundity wasinfluenced more byweight and productivelength. The research is beginning to IDthe broodstockin our country

    Exploring the role of individual level and firm level dynamic capabilities in SMEs’ internationalization

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    This paper presents a multi-level model that examines the impact of dynamic capabilities on the internationalization of SMEs while taking into account the interactions among them. The purpose of the research is to understand the applicability of dynamic capabilities at the individual and the firm level to the SME internationalization process in developing country context and to assess to what extent a firm’s asset position and individual level dynamic capabilities influence the generation of firm level dynamic capabilities in SMEs. First, the dynamic capabilities theory was theoretically linked to the internationalization phenomenon. The relationships among firm-level dynamic capabilities, individual-level dynamic capabilities (owner specific dynamic capabilities), and internationalization were identified. The research framework and hypotheses were developed and empirically tested with 197 SMEs. The findings established that owner-specific dynamic capabilities have a positive influence on both firm dynamic capabilities and internationalization, and firm dynamic capabilities positively influence internationalization. It was also found that the market assets position measured as perceptual environmental dynamism positively influenced firm dynamic capabilities but structural and reputational asset positions of SMEs did not influence generation of firm dynamic capabilities. Moreover, firm dynamic capabilities had a mediation effect in the relationship between owner-specific dynamic capabilities and internationalization. Theoretically, this confirms the relevance of dynamic capability theory to internationalization and the possibility of integrating existing internationalization theories. Entrepreneurs, SME managers, and policy-makers could gain valuable insights on how entrepreneur and firm capabilities lead to better international prospects from this outcome
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