Numerical analysis of flow and heat transfer in the VAFB LOX storage Dewar tank

The present report describes numerical simulation of three-dimensional transient distributions of velocity and temperature of liquid oxygen (LOX) in the LOX Dewar tank of Vendenberg Air Force Base (VAFB). The present analyses cover the replenish time period only. Four test cases have been considered. For all four cases, the input boundary conditions are comprised of LOX facility heat loads, drain flow rates, recirculation flow rates and dewar heating. All the quantities are prescribed as functions of time. The first two test cases considered sensitivity of results to the computational grid. In Case 3, system heat load was changed, while in Case 4, a lower LOX level was specified. Cases 1 and 2 showed that the temperatures were not sensitive to the grid refinement. This provided a basic check on the numerical model. Cases 3 and 4 showed that the thermal boundary layer motion near the tank surface becomes more significant at the late time, e.g., 5 1/2 hours from replenish start. Comparison between results of Cases 3 and 4 showed, as expected, that the smaller initial LOX volume given in Case 4, results in higher temperature level. All calculated velocity and temperature distributions were found to be plausible

Discrete element weld model, phase 2

A numerical method was developed for analyzing the tungsten inert gas (TIG) welding process. The phenomena being modeled include melting under the arc and the flow in the melt under the action of buoyancy, surface tension, and electromagnetic forces. The latter entails the calculation of the electric potential and the computation of electric current and magnetic field therefrom. Melting may occur at a single temperature or over a temperature range, and the electrical and thermal conductivities can be a function of temperature. Results of sample calculations are presented and discussed at length. A major research contribution has been the development of numerical methodology for the calculation of phase change problems in a fixed grid framework. The model has been implemented on CHAM's general purpose computer code PHOENICS. The inputs to the computer model include: geometric parameters, material properties, and weld process parameters

Dynamic Body VSLAM with Semantic Constraints

Image based reconstruction of urban environments is a challenging problem that deals with optimization of large number of variables, and has several sources of errors like the presence of dynamic objects. Since most large scale approaches make the assumption of observing static scenes, dynamic objects are relegated to the noise modeling section of such systems. This is an approach of convenience since the RANSAC based framework used to compute most multiview geometric quantities for static scenes naturally confine dynamic objects to the class of outlier measurements. However, reconstructing dynamic objects along with the static environment helps us get a complete picture of an urban environment. Such understanding can then be used for important robotic tasks like path planning for autonomous navigation, obstacle tracking and avoidance, and other areas. In this paper, we propose a system for robust SLAM that works in both static and dynamic environments. To overcome the challenge of dynamic objects in the scene, we propose a new model to incorporate semantic constraints into the reconstruction algorithm. While some of these constraints are based on multi-layered dense CRFs trained over appearance as well as motion cues, other proposed constraints can be expressed as additional terms in the bundle adjustment optimization process that does iterative refinement of 3D structure and camera / object motion trajectories. We show results on the challenging KITTI urban dataset for accuracy of motion segmentation and reconstruction of the trajectory and shape of moving objects relative to ground truth. We are able to show average relative error reduction by a significant amount for moving object trajectory reconstruction relative to state-of-the-art methods like VISO 2, as well as standard bundle adjustment algorithms

Physical Acoustics

Contains reports on two research projects.U. S. Navy - Office of Naval Research (Contract NO0014-67-A-0204-0019

A Survey on Index Support for Item Set Mining

It is very difficult to handle the huge amount of information stored in modern databases. To manage with these databases association rule mining is currently used, which is a costly process that involves a significant amount of time and memory. Therefore, it is necessary to develop an approach to overcome these difficulties. A suitable data structures and algorithms must be developed to effectively perform the item set mining. An index includes all necessary characteristics potentially needed during the mining task; the extraction can be executed with the help of the index, without accessing the database. A database index is a data structure that enhances the speed of information retrieval operations on a database table at very low cost and increased storage space. The use index permits user interaction, in which the user can specify different attributes for item set extraction. Therefore, the extraction can be completed with the use index and without accessing the original database. Index also supports for reusing concept to mine item sets with the use of any support threshold. This paper also focuses on the survey of index support for item set mining which are proposed by various authors

ANTIOXIDANT AND HEPATOPROTECTIVE EFFECT OF QUERCUS ILEX LEAVES EXTRACT IN ETHANOL INDUCED LIVER DAMAGE IN WISTAR RATS

Objective: This study was undertaken to investigate the hepatoprotective and antioxidant activity of Quercus ilex leaves extract (QILE) on ethanol-induced toxicity in Wistar rats. Methods: Hepatotoxicity was induced by administering ethanol (40%) at a dose of 7.9 gm/kg/day; p. o. (1:1 of ethanol in olive oil) for 28 d. Silymarin 100 mg/kg/day; p. o. was used as a standard drug. The whole study was divided into a prophylactic and curative study. In the prophylactic study, the Silymarin and QILE (test drug) 100, 200, and 400 mg/kg Body Weight(BW) given orally one hour before administration of 40% ethanol administration for 28 d. In the curative study, 7 d of treatment of Silymarin and QILE 200 and 400 mg/kg BW was given orally after 28 d of ethanol administration to different groups. Results: Hepatoprotectivity was confirmed by the highly significantly (p<0.001) restoration of elevated biochemical parameters like SGPT, SGOT, ALP, TB, and highly significantly (p<0.001) depleted Albumin and Total protein levels by 200 mg/kg BW QILE in comparison to the positive control group. QILE 200 mg/kg highly significantly (p<0.001) raised the antioxidants by draining the elevated oxidative stress markers in comparison of positive control group. At dose levels QILE 200 mg/kg, significant (p<0.05) protection from loss in body weight and in liver weight was found when the comparison was done with the positive control group. Histopathology revealed that QILE 200 mg/kg reduced the markers of cell necrosis. Conclusion: Present study revealed that Quercus ilex leaves have antioxidant and hepatoprotective activity due to its chemical constituents

A comparative randomized controlled parallel group study of efficacy and tolerability of labetalol versus methyldopa in the treatment of mild preeclampsia

Background: The objective of the current study was to compare the efficacy and tolerability of labetalol versus methyldopa in the treatment of mild preeclampsia.Methods: We carried out a prospective randomized controlled parallel group study on 100 outpatients of Obstetrics and Gynaecology Department of Government Medical College, Patiala, a tertiary care teaching hospital. Pregnant patients (20-40 weeks gestational age) newly diagnosed with blood pressure (BP) of ≥140/90 mm Hg were included in the study. All patients with systolic BP (SBP) ≥160 mm Hg and diastolic BP (DBP) ≥110 mm Hg after 20 weeks of gestation, history of hypertension, renal diseases, diabetes mellitus, epilepsy, and thyroid diseases were excluded from the study. After taking the informed consent, 50 patients each were randomized to either of the two treatment arm-oral labetalol or oral methyldopa. Difference in the BP measurements at the time of admission and at the time of delivery were analyzed by applying paired t-test. For intergroup analysis, we applied independent t-test using SPSS version 16. A p<0.05 was regarded as significant.Results: Both methyldopa and labetalol cause significant fall in SBP, DBP and mean arterial pressure (MAP) in their groups (p<0.001). However, when we compared both groups it was labetalol, which causes significant fall in MAP as compared to methyldopa (p<0.001). The incidence of adverse effects like hypotension, headache, and sedation were also less in labetalol group.Conclusion: Labetalol has an upper edge over methyldopa in control of BP during pregnancy with minimal adverse effects