Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 4: OEPSS design concepts

This study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advanced Launch System (ALS) program, the results of the OEPSS study have been organized into a series of OEPSS Data Books. This volume describes three propulsion concepts that will simplify the propulsion system design and significantly reduce operational requirements. The concepts include: (1) a fully integrated, booster propulsion module concept for the ALS that avoids the complex system created by using autonomous engines with numerous artificial interfaces; (2) an LOX tank aft concept which avoids potentially dangerous geysering in long LOX propellant lines; and (3) an air augmented, rocket engine nozzle afterburning propulsion concept that will significantly reduce LOX propellant requirements, reduce vehicle size and simplify ground operations and ground support equipment and facilities

An investigation on relationship of chemical indices of kilka (Clupeonella engrauliformis) with weight loss during cold storage at -18C

We studied the relationship between physical and chemical properties of frozen kilka with weight loss for packed and unpacked products during storage at amal 8 ' C. Statistical analysis of the results including variance, Duncan test and ANOVA showed relationships existed between changes in Total Volatile Nitrogen (TVN), Peroxide Value (PV), pH, moisture, organoleptic properties of frozen packed and unpacked kilka with product weight losses during cold storage at -18°C. The statistical treatment of the results showed that weight losses for packed samples in comparison to unpacked one at the level of P<0.0I was significant. The weight losses, changes of TVN, PV, pH and moisture losses for unpacked samples were 1.5, 1.35, and 4.5, 132 and 1.32 times more in comparison to the packed one, respectively. Also, the statistical analysis of the results showed a correlation between weight losses in unpacked samples of frozen kilka and the measured factors. The results of chemical and physical properties measured for packed samples of frozen kilka during cold storage and their statistical analysis showed a significant correlation P<0.01 between weight losses and the changes in TVN from 7 to 28mg/100gr, PV from 2.28 to 6.01meq/kg, pH from 6.08 to 6.37 and 1.72% loss in the moisture of the samples. According to these results and the organoleptic tests, the shelf life for packed and unpacked frozen kilka in cold storage at 48°C, is recommended 60 and 30 days, respectively

The Effect of Social Responsibility and Corporate image on Enhancing the Brand Equity

Customers are one of the pillars of success in organizations and have been studied from different aspects. The aim of this study is scrutinizing the factors influencing brand equity in the tobacco industry in Tehran. Therefore, by referring to previous studies, dimensions and components of associated with variables have been identified and a standard questionnaire based on these variables has been used. The validity of the questionnaire has been approved by the elites of management and the reliability of them has been calculated through the software. The statistical population of research consisted of all customers of the tobacco industry in Tehran. In order to determining the sample size the Cochran formula, to the extent of 384 individuals, has been used. In order to test the research hypotheses Structural equation modeling through Lisrel software has been used. The results showed that different variables have significant impact on brand equity and customer loyalty is an important mediating factor in influencing on brand equity

An Experimental Study on Concrete’s Durability and Mechanical Characteristics Subjected to Different Curing Regimes

 Considering a constant demand in construction of concrete structures to develop novel approaches for predicting the concert’s properties, a host of investigations were performed on concrete’s mechanical properties and durability under various curing regimes. However, few studies were concerned with evaluating the concrete’s durability using non-destructive concrete surface resistivity tests by applying various curing conditions. The present study compares the influence of different curing regimes on durability and compressive strength of concrete to recommend the most effective curing conditions on concrete’s characteristics.  Five curing conditions including ambient, laboratory, dry oven, wet oven and 7-days were analyzed. Accordingly, a non-destructive concrete surface resistivity test was performed on the concrete specimens using hand-held Wenner Resipod probe meter as a reliable and rapid approach. To analyze specimen’s durability, results of the surface sensitivity tests were correlated to chloride ion penetration rate based on the cylinder specimen dimensions and the degree of chloride ion penetration. The compressive strength tests were conducted on the specimens after 7, 28 and 56 days to determine the effect of curing conditions at different ages. Based on the reported outcomes, applying the wet oven curing regime results in higher compressive strength and durability compared to the other curing conditions. Doi: 10.28991/cej-2021-03091681 Full Text: PD

Classification of organizational failure root causes producing human error

The formal study of human error is relatively recent, especially in medical domain, and is tied closely to a several other relatively new fields. Organizational root cause of human error is less considered. Despite growing social, industrial and scientific interest in the organizational causes of incidents, the concept of organizational failure and related tools are still less considered in many developing countries e.g. Iran. Also, there is few incident record-keeping in medical domain on human error. Therefore, this study draws on case study research to investigate the applicability of a European taxonomy of organizational failure in Iran, in aviation domain with a fair incident record-keeping. This case study resulted in 10 incident in-depth descriptions, which occurred during one year in a part of civil aviation due to operator error. Within each case study, an explanation building method is used to develop a tool for classifying organizational root causes. Results include 100 root causes. The distribution of organizational root causes over the main categories of the former taxonomy shows a need to add a new sub-category to improve its applicability in Iran. The new sub-category is related to culture

Mental health in high-tech system

Stress and mental health at the place of work have received great attention by researchers. In spite of technology improvement in high-tech systems, the operators face new problems, which can affect mental health. There is hardly any published research about stress or mental health in such workplaces in developing countries. This paper presents the application of the self-rating scale General Health Questionnaire (GHQ-28) to study mental health of 160 controllers working in a part of Air Traffic Control (ATC) as a high tech system in Iran. Logistic regression analysis showed that demographic variables did not exhibit a statistically significant effect on scores of the test. In order to compare mental health of these operators with general population, an exposure / non-exposure study was designed. Three age groups (less than 29 years, 30 through 39 y, and more than 40 y) were compared in exposed and non-exposed groups. The results of Fisher’s exact test showed that mental distress symptoms were significantly higher in the exposed group. There were significant job effects on somatization, anxiety and depression as well as on the total score of GHQ-28 for the two first age groups (P<.05). No significant effects of the job were found on social dysfunction symptoms in any age groups. The risk ratio of expressing depression and anxiety symptoms were more than three times greater in these operators than general population

SEX-SPECIFIC RESTORATION OF MK-801-INDUCED SENSORIMOTOR GATING DEFICIT BY ENVIRONMENTAL ENRICHMENT

Despite ample evidence of N-methyl-D-aspartate (NMDA) receptor dysfunction in schizophrenia, no study has addressed the effects of enriched environment (EE) on sensorimotor gating deficits induced by postnatal NMDA receptor blockade. We evaluated the effect of EE on sensorimotor gating (measured by prepulse inhibition, PPI), or on sensorimotor gating deficit induced by the NMDA receptor antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cy clohepten-5,10-imine maleate (MK-801) in both sexes of Wistar rats. Rats were injected with MK-801 (1 mg/kg) on postnatal days (P) 6–10. EE was provided from birth up to the time of experiments on P28–30 or P58–60. PPI data were collected at three prepulse intensities and then averaged to yield global PPI. MK-801 treatment reduced PPI significantly in both sexes. While EE per se had no significant effect on PPI, it restored MK-801-induced PPI deficit only in male rats. An extended period of EE did not influence PPI deficit in female rats. Our results indicate that postnatal exposure to MK-801 may exert long-lasting effects on neuronal circuits underlying sensorimotor gating. Sex-specific modulation of such effects by EE suggests sexually dimorphic mechanisms are involved. � 2015 IBRO. Published by Elsevier Ltd. All rights reserved

Improvement in the Production of L-Lysine by Overexpression of Aspartokinase (ASK) in C. glutamicum ATCC 21799

Purpose: To clone Corynebacterium glutamicum ATCC21799 aspartokinase gene (EC 2.7.2.4) using shuttle expression vector pEKEx2 in order to increase lysine production.Methods: C. glutamicum DNA was extracted and used for amplification of aspartokinase gene (ask) by cloning into an E. coli/C. glutamicum shuttle expression vector, pEKEx2. Initially, the recombinant vector transformed into E. coli DH5á and then into C. glutamicum.Results: Electrophoresis of recombinant protein by SDS-PAGE showed that the molecular weight of the recombinant protein was 42 KD. The induction of recombinant vector by IPTG had an inhibitory effect on cell growth due to over-expression of the cloned gene. The results of lysine assay by Chinard method showed that lysine production increased about two-fold, compared with the parent strain, as a result of increased copy numbers of lysC gene in recombinant strain.Conclusion: A two-fold increase in lysine production was observed by cloning of the ASK gene in C. glutamicum rather than in E. coli, due to the presence of lysine exporter channel which facilitates lysine extraction.Keywords: LysC gene, Corynebacterium glutamicum, L- lysine, Cloning, Aspartokinase, E. col