Application of nitrogen metabolism in autotrophic bacteria to chemosynthetic bioregeneration in space missions, supplement

The chemolithotroph, Hydrogenomonas eutropha, was considered as a life support, bioregenerative system. This project focuses on several metabolic functions that are related to the proposed nitrogen cycle between man and this microbe. Specifically this organism has the capability to utilize as the sole nitrogen source such urine components as urea and fifteen individual amino acids, but not nine other amino acids. The effectiveness of utilization was high for many amino acids. Several specific growth inhibitions were also observed. The enzyme that catalyzes the incorporation of ammonia in the medium into amino acids was identified as a NADP-specific, L-glutamate dehydrogenase. This enzyme has a constitutive nature. This organism can synthesize all of its amino acids from carbon dioxide and ammonia. Therefore with the background literature of multiple pathways of individual amino acid biosyntheses, our evidence to date is consistent with the Hydrogeneomonas group having the same pathway of valine-isoleucine formation as the classical E. coli

Self-propagating high temperature synthesis and dynamic compaction of titanium diboride/titanium carbide composites

Self-propagating High-temperature Synthesis (SHS) of titanium and boron carbide (B 4 C) combined with explosively driven Dynamic Compaction (DC) was employed for the fabrication of composite TiB 2 /TiC compacts. A 2 3 factorially designed experiment set was used to examine the effects of the TiB 2 /TiC ratio, delay time and C/M ratio on the consolidation and properties of the compacts. The delay time is the time between completion of the SHS reaction and compaction. The C/M ratio, the ratio of the explosive mass to that of the flyer plate, influences the pressure applied to the samples during compaction. Composites with molar TiB 2 /TiC ratios of 2:1 or 1:2 were prepared using Ti and B 4 C or Ti, C and B 4 C, respectively, as reactants. The SHS/DC of Ti and B 4 C resulted in high quality, near fully dense TiB 2 /TiC composite compacts. Under best conditions, the densities were greater than 98% of the theoretical maximum. While the microhardness and densities of the compacts with TiB 2 /TiC ratio of 2:1 were comparable to those of monolithic TiB 2 and TiC, compacts with TiB 2 /TiC ratios of 1:2 were poorly consolidated and contained extensive cracks. Given the high energy and time efficiency, high product quality and inexpensive reactants, the SHS/DC of Ti and B 4 C represents an attractive technique for the economical fabrication of TiB 2 /TiC composites.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44760/1/10853_2004_Article_263157.pd

Using Management Objectives to Specify Management Information Systems - A Contribution to MIS Success

Data warehouse projects, today, are in an ambivalent situation. On the one hand, data warehouses are critical for a company’s success and various methodological and technological tools are sophisticatedly developed to implement them. On the other hand, a significant amount of data warehouse projects fails due to non-technical reasons such as insufficient management support or in-corporative employees. But management support and user participation can be increased dramatically with specification methods that are understandable to these user groups. This paper aims at overcoming possible non-technical failure reasons by introducing a user-adequate specification approach within the field of management information systems.\u

A conceptual framework for the adoption of big data analytics by e-commerce startups: a case-based approach

E-commerce start-ups have ventured into emerging economies and are growing at a significantly faster pace. Big data has acted like a catalyst in their growth story. Big data analytics (BDA) has attracted e-commerce firms to invest in the tools and gain cutting edge over their competitors. The process of adoption of these BDA tools by e-commerce start-ups has been an area of interest as successful adoption would lead to better results. The present study aims to develop an interpretive structural model (ISM) which would act as a framework for efficient implementation of BDA. The study uses hybrid multi criteria decision making processes to develop the framework and test the same using a real-life case study. Systematic review of literature and discussion with experts resulted in exploring 11 enablers of adoption of BDA tools. Primary data collection was done from industry experts to develop an ISM framework and fuzzy MICMAC analysis is used to categorize the enablers of the adoption process. The framework is then tested by using a case study. Thematic clustering is performed to develop a simple ISM framework followed by fuzzy analytical network process (ANP) to discuss the association and ranking of enablers. The results indicate that access to relevant data forms the base of the framework and would act as the strongest enabler in the adoption process while the company rates technical skillset of employees as the most important enabler. It was also found that there is a positive correlation between the ranking of enablers emerging out of ISM and ANP. The framework helps in simplifying the strategies any e-commerce company would follow to adopt BDA in future. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

Structural and mechanical properties of TiB 2 and TiC prepared by self-propagating high-temperature synthesis/dynamic compaction

Titanium-diboride and titanium-carbide compacts with diameters of 100 mm and thicknesses of 25 mm were fabricated by self-propagating high-temperature synthesis/dynamic compaction (SHS/DC) of the elemental powders. Under the best conditions, the densities were greater than 99% and 96.8% of the theoretical densities for TiB 2 and TiC, respectively. The microhardness, compressive strength, and elastic modulus of the TiB 2 prepared by the SHS/DC method were comparable to reported values for hot-pressed TiB 2 . While the microhardness and elastic modulus of the TiC compacts were comparable to those for hotpressed TiC, the compressive strength was lower due to extensive cracks in the compacts. The TiB 2 prepared using a low-purity boron powder (1–5% carbon impurity) compacted to higher densities and had less cracking than that prepared using a high-purity boron powder (0.2% carbon). This result could have an impact on the cost of producing TiB 2 /TiC structural components by the SHS/DC process.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44732/1/10853_2005_Article_BF01162518.pd