Design optimization of coil gun to improve muzzle velocity

Recently, a coil gun was brought to the attention of engineering community as electromagnetic alternative to the chemical launchers. Various studies were performed on coil gun systems focused on achieving the high muzzle velocity in military applications and for satellite launching. Most of these studies focused on improvement of muzzle velocity via increase in the size of the coil gun. Present paper describes the process of design optimization where the size of the coli gun system is restricted. The design of experiment approach utilizes the orthogonal array table that reduces the required number of experiments. The design of experiment is carried out with a commercial PIAnO tool, where the finite element analysis is performed at each experimental point. Then, Kriging model is created to achieve accurate approximation in problems of many design variables or strongly nonlinear model. The coil gun is optimally designed using an evolutionary algorithm (EA) as optimization technique. In order to verify the improvement of muzzle velocity by optimal design, the prototypes of coil gun system are manufactured and the experiments to launch the projectile are performed

Concordance between the underlying causes of death on death certificates written by three emergency physicians

Objective This study was conducted to evaluate the concordance between the underlying causes of death (UCOD) on the death certificates written by three emergency physicians (EPs). We investigated errors on the death certificates committed by each EP. Methods This study included 106 patients issued a death certificate in the emergency department of an academic hospital. Three EPs reviewed the medical records retrospectively and completed 106 death certificates independently. The selection of the UCOD on the death certificates by each EP (EP-UCOD) was based on the general principle or selection rules. The gold standard UCOD (GS-UCOD) was determined for each patient by unanimous consent between three EPs. We also compared between the EP-UCOD and the GS-UCOD. In addition, we compared between UCODs of three EPs. The errors on the death certificates were investigated by each EP. Results The rates of concordance between EP-UCOD and the GS-UCOD were 86%, 81%, and 67% for EP-A, EP-B, and EP-C, respectively. The concordance rates between EP-A and EP-B were the highest overall percent agreement (0.783), and those between EP-A and EP-C were the lowest overall percent agreement (0.651). Although each EP had differences in the errors they committed, none of them listed the mode of dying as UCOD. Conclusion This study confirmed that each EP wrote death certificates indicating different causes of death for the same decedents; however, the three EPs made fewer errors on the patients’ death certificates compared with those reported in previous studies

Design optimization of coil gun to improve muzzle velocity

Recently, a coil gun was brought to the attention of engineering community as electromagnetic alternative to the chemical launchers. Various studies were performed on coil gun systems focused on achieving the high muzzle velocity in military applications and for satellite launching. Most of these studies focused on improvement of muzzle velocity via increase in the size of the coil gun. Present paper describes the process of design optimization where the size of the coli gun system is restricted. The design of experiment approach utilizes the orthogonal array table that reduces the required number of experiments. The design of experiment is carried out with a commercial PIAnO tool, where the finite element analysis is performed at each experimental point. Then, Kriging model is created to achieve accurate approximation in problems of many design variables or strongly nonlinear model. The coil gun is optimally designed using an evolutionary algorithm (EA) as optimization technique. In order to verify the improvement of muzzle velocity by optimal design, the prototypes of coil gun system are manufactured and the experiments to launch the projectile are performed

Design optimization of coil gun to improve muzzle velocity

Recently, a coil gun was brought to the attention of engineering community as electromagnetic alternative to the chemical launchers. Various studies were performed on coil gun systems focused on achieving the high muzzle velocity in military applications and for satellite launching. Most of these studies focused on improvement of muzzle velocity via increase in the size of the coil gun. Present paper describes the process of design optimization where the size of the coli gun system is restricted. The design of experiment approach utilizes the orthogonal array table that reduces the required number of experiments. The design of experiment is carried out with a commercial PIAnO tool, where the finite element analysis is performed at each experimental point. Then, Kriging model is created to achieve accurate approximation in problems of many design variables or strongly nonlinear model. The coil gun is optimally designed using an evolutionary algorithm (EA) as optimization technique. In order to verify the improvement of muzzle velocity by optimal design, the prototypes of coil gun system are manufactured and the experiments to launch the projectile are performed

The Effect of Age at First Calving and Calving Interval on Productive Life and Lifetime Profit in Korean Holsteins

This study was performed to estimate the effect of age at first calving and first two calving intervals on productive life and life time profit in Korean Holsteins. Reproduction data of Korean Holsteins born from 1998 to 2004 and lactation data from 276,573 cows with birth and last dry date that calved between 2000 and 2010 were used for the analysis. Lifetime profit increased with the days of life span. Regression of Life Span on Lifetime profit indicated that there was an increase of 3,800 Won (approximately $3.45) of lifetime profit per day increase in life span. This is evidence that care of each cow is necessary to improve net return and important for farms maintaining profitable cows. The estimates of heritability of age at first calving, first two calving intervals, days in milk for lifetime, lifespan, milk income and lifetime profit were 0.111, 0.088, 0.142, 0.140, 0.143, 0.123, and 0.102, respectively. The low heritabilities indicated that the productive life and economical traits include reproductive and productive characteristics. Age at first calving and interval between first and second calving had negative genetic correlation with lifetime profit (−0.080 and −0.265, respectively). Reducing age at first calving and first calving interval had a positive effect on lifetime profit. Lifetime profit increased to approximately 2,600,000 (2,363.6) from 800,000 Won ($727.3) when age at first calving decreased to (22.3 month) from (32.8 month). Results suggested that reproductive traits such as age at first calving and calving interval might affect various economical traits and consequently influenced productive life and profitability of cows. In conclusion, regard of the age at first calving must be taken with the optimum age at first calving for maximum lifetime profit being 22.5 to 23.5 months. Moreover, considering the negative genetic correlation of first calving interval with lifetime profit, it should be reduced against the present trend of increase

Accuracy of Imputation of Microsatellite Markers from BovineSNP50 and BovineHD BeadChip in Hanwoo Population of Korea

Until now microsatellite (MS) have been a popular choice of markers for parentage verification. Recently many countries have moved or are in process of moving from MS markers to single nucleotide polymorphism (SNP) markers for parentage testing. FAO-ISAG has also come up with a panel of 200 SNPs to replace the use of MS markers in parentage verification. However, in many countries most of the animals were genotyped by MS markers till now and the sudden shift to SNP markers will render the data of those animals useless. As National Institute of Animal Science in South Korea plans to move from standard ISAG recommended MS markers to SNPs, it faces the dilemma of exclusion of old animals that were genotyped by MS markers. Thus to facilitate this shift from MS to SNPs, such that the existing animals with MS data could still be used for parentage verification, this study was performed. In the current study we performed imputation of MS markers from the SNPs in the 500-kb region of the MS marker on either side. This method will provide an easy option for the labs to combine the data from the old and the current set of animals. It will be a cost efficient replacement of genotyping with the additional markers. We used 1,480 Hanwoo animals with both the MS data and SNP data to impute in the validation animals. We also compared the imputation accuracy between BovineSNP50 and BovineHD BeadChip. In our study the genotype concordance of 40% and 43% was observed in the BovineSNP50 and BovineHD BeadChip respectively

The Stability of Hydroxyapatite/Poly-L-Lactide Fixation for Unilateral Angle Fracture of the Mandible Assessed Using a Finite Element Analysis Model

Recently, a hydroxyapatite particle/poly-L-lactide (HA-PLLA) composite device was introduced as an alternative to previous fixation systems. In this study, we used finite element analysis to simulate peak von Mises stress (PVMS) and deformation of bone plates and screws with the following four materials—Ti, Mg alloy, PLLA, and HA-PLLA—at a unilateral mandibular fracture. A three-dimensional virtual mandibular model was constructed, and the fracture surface was designed to run from the left mandibular angle. Masticatory loading was applied on the right first molars. Stress was concentrated at the upper part and the neck of the screw. The largest PVMS was observed for Ti; that was followed by Mg alloy, HA-PLLA, and PLLA. The largest deformation was observed for PLLA; next was HA-PLLA, then Mg alloy, and finally Ti. We could rank relative superiority in terms of mechanical properties. The HA-PLLA screw and mini-plate deformed less than 0.15 mm until 300 N. Thus, we can expect good bone healing with usual masticatory loading six weeks postoperatively. HA-PLLA is more frequently indicated clinically than PLLA owing to less deformation. If the quality of HA-PLLA fixation is improved, it could be widely utilized in facial bone trauma or craniofacial surgery

ANALYSIS OF REGIONAL GROWTH: A STUDY OF EFFICIENCY/EQUALITY RELATIONS

The research is concerned with the process of regional growth. The purpose is two-fold: (i) to analyze the relations between national aggregate efficiency and interregional income equality in the regional policy decision-making process; and (ii) to explain the historic change in the levels of interregional income inequality in the United States. The study gives particular attention to two different political-economic systems: a planned economy and a free market system. The analysis of regional growth in a planned economy shows the relations between two regional policy goals (i.e., efficiency and equality) through both static and dynamic analyses. The important policy variable adopted here is the regional allocation of investment. This study departs from the existing literature by dropping faulty assumptions from neoclassical regional economic growth theory such as: (i) constant returns to scale; (ii) identical production functions; and (iii) a two-region economy. The static analysis presents various relations between efficiency and equality such as trade-off, non-trade-off and mixed-relations. The dynamic analysis concludes that the two goals conflict in most cases, even though there might be some fluctuation on the short-term planning horizon. The analysis of regional growth in a free market system deals with the following question: Why do regional income inequalities decrease (or increase) as the economy develops? The study shows several interesting results. First, regional income inequalities in the U.S. have been decreasing over time except for the short-time effect of the Great Depression. This finding is quite different from Myrdal\u27s expectation and Williamson\u27s inverted-U hypothesis. Second, neoclassical growth theory as a theoretical rationale for interregional income convergence has a limited predictive accuracy. Both empirical and theoretical analyses indicate that interregional factor flows neither ensure full convergence nor full divergence. Finally, it has been found that the convergence toward regional equality is caused by the long-term geographic dispersion of factors such as wage income, property income, transfer payments, the urbanization rate, the employment structure and the labor participation rate. It is concluded that the convergence results from intraregional, rather than interregional, allocation of resources