Mechanical and Structural Behavior of Granular Material Packed Beds for Space Life Support System Applications

Long-term human mission to space, such as living in International Space Station (ISS), Lunar, and Martian bases, and travel to Mars, must m ake use of Advanced Life Support Systems (ALSS) to generate and recycle critical life supporting elements like oxygen and water. Oxygen Gen eration Assembly (OGA) and Water Processor Assembly (WPA), critical c omponents of ALSS, make use of series of granular material packed beds for generation and recycling of oxygen and water. Several granular m aterials can be used for generation, recycling, processing and recovery of oxygen and water. For example, they may include soft bed media, e.g. ion exchange resins for oxygen generation assembly and hard bed media such as, activated alumina, magchem (Magnesium oxide) and activa ted carbon to remove organic species like ethanol, methanol, and urea from wastewater in Water recovery/processing assembly. These beds are generally packed using a plate-spring mechanism to provide sufficien t compaction to the bed media throughout the course of operation. This paper presents results from an experimental study of a full-scale, 3 8.1 cm (15 inches) long and 3.7 cm (1.44 inches) diameter. activated alumina bed enclosed in a cylinder determining its force-displacement behavior, friction mobilizing force, and axial normal stress distribu tion under various axially applied loads and at different levels of packing. It is observed that force-displacement behavior is non-linear for low compaction level and becomes linear with increase in compaction of the bed media. Axial normal stress distribution along the length of the bed media decreased non-linearly with increase in depth from the loading end of the granular media. This paper also presents experimental results on the amount of particulates generated corresponding to various compaction levels. Particulates generated from each of the tests were measured using standard US sieves. It was found that the p articulates and the overall displacement of the bed media increased with decrease in initial compaction of the bed media. This effect could be attributed to the greater tendency for inter-particle sliding/rub bing due to smaller internal friction angles, as seen from the shear tests, at lesser initial compacted levels. Upon unloading, it was obse rved that there was no change in displacement (especially rebounding) in the bed media. This effect could be attributed to the fact that th e porous activated alumina particles fracture/break upon increase in applied load (during loading phase) and occupy void spaces in between the material grains; thereby leading to settling of the media. The lo ad-displacement curve becomes more linear with increase in initial compaction of the bed media. It is concluded that compaction considerabl y affects the load-displacement behavior of the bed media. A series of tests were also conducted on the packed bed media to determine the f orce required to mobilize the friction between the bed media and the housing cylinder. The results from these tests showed the existence of significant friction between the bed media and the encasing stainles s steel cylinder. Further, it was found that friction effects were more pronounced for media with higher initial compaction. Internal frict ion of the granular media was measured using direct shear apparatus. It was observed that the internal friction increased with increase in initial compaction of the bed media. In this study, a computational m odel (CM) is also developed using finite element software ANSYS to verify experimental results obtained for the distribution of the axial n ormal stress and axial displacement along the length of the full-scal e activated alumina bed media. In the computational model, the granular material is considered to have appropriate failure and frictional c ontact exists between the wall and the granular media. It is observed that the model predicts results closely with the experimental method. The compational results show that the axial normal stress distribution along the length of the activated alumina media decreases non-linea rly from the loading end and is negligible beyond a certain depth. Th is can be attributed to the existence of friction between the walls and the media and that the friction takes up most of the applied load

Application of GPS tracking techniques to orbit determination for TDRS

In this paper, we evaluate two fundamentally different approaches to TDRS orbit determination utilizing Global Positioning System (GPS) technology and GPS-related techniques. In the first, a GPS flight receiver is deployed on the TDRSS spacecraft. The TDRS ephemerides are determined using direct ranging to the GPS spacecraft, and no ground network is required. In the second approach, the TDRSS spacecraft broadcast a suitable beacon signal, permitting the simultaneous tracking of GPS and TDRSS satellites from a small ground network. Both strategies can be designed to meet future operational requirements for TDRS-2 orbit determination

Synthesis of multifunctional nanocomposite material: tungstate-pillared Mg-Al hydrotalcite-like compound

Hydrotalcite-like compounds (HTLC) with different cationic ratios (Mg/AI) and charge-balancing inter layer anions were prepared and characterized. The surface areas of HTLCs were found to increase with increasing Mg/AI ratio. Pure HTLCs were obtained when the Mg/AI ratio was below 7. Water adsorption properties of HTLCs show that they are microporous. BET surface areas with water and nitrogen are dependent on the Mg/AI ratio of HTLC. Tungstate-pillared HTLC (synthesized from Mg/AI=7) was prepared and characterized, resulting in higher gallery height and surface area

Law Enforcement Agencies in Disaster Response in Nepal: Analyzing the Competency of the Nepal Police and the Armed Police Force

Although Nepal Police and Armed Police Force are the key responding tools of disaster response in Nepal, their response competency does not suffice the need for effective response. Applying quantitative research methodology, this research has in-depth investigated the fundamental and technical knowledge, and preparedness activities of such police personnel. Ultimately it was discovered that their knowledge and preparedness are not adequate to meet the need. On the other hand, the practice of the usage of disaster untrained police personnel in response operations is prevalent in the country. And this tendency is not only risking the life of the disaster victims but also putting the responders’ lives at stake. Amidst such bleakness, during the investigation, the perception of the police personnel on their engagement in disaster response was found highly aspiring. Indeed this tendency will work as the force multiplier if their capacity is enhanced properly. The study has further investigated that the lethargic national investment in the disaster response capacity building process is the fundamental problem in terms of the competency building process. Heavy reliance on foreign aids and national and international non-government agencies has not only increased the dependency on capacity building process but also mired the national mechanism turning responsible authorities and institutions lethargic

Draft bills and research reports on: reducing judicial corruption and child labor in Nepal

These two draft bills and accompanying research report comprise the work of two teams of Nepali officials from Nepal's Ministry of Law and Justice who prepared them in the context of the Boston University School of Law Program on Legislative Drafting for Democratic Social Change. They attended that Program as part of a larger Ministry of Law and Justice Program, funded by the United Nations Development Program (UNDP), to strengthen Nepal's legal framework and the Rule of Law. Using the bills and reports as case studies, the four officials aimed to learn legislative theory, methodology and techniques. The Ministry had assigned them, on their return to Nepal, to play a significant role in institutionalizing an on-going learning process to strengthen Nepali drafters' capacity to prepare the effectively implementable legislation necessary to ensure good governance and development

HRD practices in co-operative sugar mills in north coastal andra pradesh

Human resources are considered as the most valuable strategic assets to the organization. The success of any organization depends on the efficient use of human resources in the organization. This paper aims to analyze the various Human resource development (HRD) practices in the co-operative sugar industry in north coastal Andhra Pradesh. The study measured an evaluation of HRD practices in the sugar industry. A sample of 100 employees from five co-operative sugar mills responded to a questionnaire which measured the evaluation of HRD practices and improves the values. HRD practices like training and development, performance appraisal system, quality of work life and development were positively related to organizational values of humane treatment. However, performance appraisal system, career planning, and contextual analysis variables were negatively associated with values such as trust and creativity. The analysis was limited to existing HRD practices. Further studies are needed on a larger sample to examine why some HRD practices and contextual analysis contributed negatively to organizational values. The result of the study can be useful in designing effective employee development programs that promote cherished organizational values. Little empirical knowledge exists on HRD practices and organizational values linkages in the context of the co-operative sugar industry in Andrapradesh. The paper makes a modest attempt to fill the gap

A review of GPS-based tracking techniques for TDRS orbit determination

This article evaluates two fundamentally different approaches to the Tracking and Data Relay Satellite (TDRS) orbit determination utilizing Global Positioning System (GPS) technology and GPS-related techniques. In the first, a GPS flight receiver is deployed on the TDRS. The TDRS ephemerides are determined using direct ranging to the GPS spacecraft, and no ground network is required. In the second approach, the TDRS's broadcast a suitable beacon signal, permitting the simultaneous tracking of GPS and Tracking and Data Relay Satellite System satellites by ground receivers. Both strategies can be designed to meet future operational requirements for TDRS-II orbit determination

ANTIOXIDANT AND ANTIPROLIFERATIVE POTENTIALS OF MARINE ACTINOMYCETES

Objective: The aim of present studyis to isolate and characterize a novel actinomycetes strain from marine sediments collected at Kakinada coast. To evaluate antioxidant and antiproliferative activities of the crude methanolic extract of isolated actinomycetes.Methods: Actinomycetes was isolated from marine sediments collected at Kakinada coast using starch casein agar. Morphological, biochemical and molecular characterization was performed and the crude methanolic extract was used for determination of in vitro antioxidant activity and antiproliferative activity against MDA-MB 231 breast cancer cells.Results: The crude methanolic extract exhibited significant antioxidant activity with IC­50­ value in the range of 30-46 µg/ml in different radical scavenging assays. Moreover, the extract showed concentration dependent cytotoxicity against triple negative breast cancer cell line, MDA-MB 231 with IC50 of 42.5µg/ml. The extract also inhibited cell proliferation with IC50 value 44.1 µg/ml probably by arresting cell cycle at S phase. The antioxidant activity of the extract was strongly correlated with cytotoxic and antiproliferative activity.Conclusion: The isolated marine actinomycetes can be the potential source of antioxidants with the anticancer property

Spatial orientations of angular momentum vectors of galaxies in Supercluster S [173+014+0082]

The spin vector orientation of 1302 SDSS (Sloan Digital Sky Survey) galaxies in Supercluster S[173+014+0082] having redshift 0.076 to 0.091 has been analyzed. The positions, position angles, and inclination angles of galaxies are used to convert two-dimensional observed parameters into three-dimensional angular momentum vectors of the galaxy using the `position angle-inclination' method. The expected isotropic distribution curves are determined by performing numerical simulation by generating 107 virtual galaxies. The observed distribution is compared with the expected isotropic distribution curves using three statistical tools namely Chi-square test, autocorrelation test, and Fourier test. Redshift map is studied and found that the distributions fit with the Gaussian. No preferred alignment of angular momentum vectors is noticed, supporting the Hierarchy model of galaxy formation. BIBECHANA 18 (1) (2021) 26-32