Cooling system design tool for rapid development and analysis of chilled water systems aboard U.S. Navy surface ships

Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis. Vita.Includes bibliographical references (p. 155-157).Over the last several decades, there has been a dramatic increase in the complexity and power requirements of radars and other combat systems equipment aboard naval combatants and this trend is expected to continue for the foreseeable future. This increase in the power demand has a direct effect on the amount of heat which has to be removed by the cooling systems, with future combatants expected to require 5-10 times the cooling capacity currently installed on naval combatants (McGillan, Perotti, McCunney, & McGovern). In the past, the cooling system could be designed and integrated into the ship towards the later stages of the ship design process; however, this is no longer possible. The growing complexity and size of the cooling systems needed require preliminary design and integration in the early-stages of the ship design process. To design and integrate cooling systems several tools are available to the naval architect, but vary in complexity and usefulness depending on the design stage considered. The focus of this thesis is on the early-stage design of cooling systems aboard U.S. Navy surface ships utilizing the principles of naval architecture and mechanical engineering concepts. The intent was to study the heat transfer process within the chilled water system and the auxiliary seawater system and develop a Cooling System Design Tool (CSDT) based on the thermodynamic laws that govern heat transfer as well as the hydrodynamic principles that govern fluid flow, specifically the incorporation of flow network analysis (FNA). The key purposes of the CSDT are to provide rapid visualization and analysis of the cooling system to test overall feasibility and performance of the system. The framework of the model was built using Matlab in conjunction with Excel. The program interacts with the user primarily through the command window, guiding the user through the design process. Some visualization is provided as the design progresses, allowing the user to quickly determine and correct errors in the design. The CSDT also displays important results of various analyses that can be performed on the data, including a weight summary, a static temperature distribution, and a temperature distribution that captures transients in space and time. The program interaction, chilled water plots and analyses output enables the user with the ability to quickly visualize, develop and analyze cooling systems aboard naval vessels.by Amiel B. Sanfiorenzo.Nav.E.and S.M

Implementation and Evaluation of Power Consumption of an Iris Pre-processing Algorithm on Modern FPGA

In this article, the efficiency and applicability of several power reduction techniques applied on a modern 65nm FPGA is described. For image erosion and dilation algorithms, two major solutions were tested and compared with respect to power and energy consumption. Firstly the algorithm was run on a general purpose processor (gpp) NIOS and then hardware architecture of an Intellectual Property (IP) was designed. Furthermore IPs design was improved by applying a number of power optimization techniques. They involved RTL level clock gating, power driven synthesis with fitting and appropriate coding style. Results show that hardware implementation is much more energy efficient than a general purpose processor and power optimization schemes can reduce the overall power consumption on an FPGA

Intranasal insulin administration decreases cerebral blood flow in cortico‐limbic regions: A neuropharmacological imaging study in normal and overweight males

Aim: To assess and compare the effects of 160 IU intranasal insulin (IN‐INS) administration on regional cerebral blood flow (rCBF) in healthy male individuals with normal weight and overweight phenotypes. / Methods: Thirty young male participants (mean age 25.9 years) were recruited and stratified into two cohorts based on body mass index: normal weight (18.5‐24.9 kg/m2) and overweight (25.0‐29.9 kg/m2). On separate mornings participants received 160 IU of IN‐INS using an intranasal protocol and intranasal placebo as part of a double‐blind crossover design. Thirty minutes following administration rCBF data were collected using a magnetic resonance imaging method called pseudocontinuous arterial spin labelling. Blood samples were collected to assess insulin sensitivity and changes over time in peripheral glucose, insulin and C‐peptide. / Results: Insulin sensitivity did not significantly differ between groups. Compared with placebo, IN‐INS administration reduced rCBF in parts of the hippocampus, insula, putamen, parahippocampal gyrus and fusiform gyrus in the overweight group. No effect was seen in the normal weight group. Insula rCBF was greater in the overweight group versus normal weight only under placebo conditions. Peripheral glucose and insulin levels were not affected by IN‐INS. C‐peptide levels in the normal weight group decreased significantly over time following IN‐INS administration but not placebo. / Conclusion: Insulin‐induced changes within key regions of the brain involved in gustation, memory and reward were observed in overweight healthy male individuals. Following placebo administration, differences in gustatory rCBF were observed between overweight and normal weight healthy individuals

Impact of Knowledge and Attitude on Preventive Practice Regarding Dengue Fever among Residents in Dasmariñas City, Cavite: A Structural Equation Modelling Approach

Dengue has been considered one of the major health problems in the world. Philippines is one of the most affected countries of this epidemic disease during the year 2015. Dasmariñas City is one of the cities in the Philippines affected by dengue fever outbreak. This study aims to assess the current level and to identify the relationships between knowledge, attitude and preventive practice about dengue fever of the respondents within Dasmariñas City, Cavite. This study used purposive sampling in selecting respondents from ten barangays with the highest number of dengue cases during the year 2015. Survey questionnaires was used to gather information from 419 respondents about their demographic profile, involvement in health promotion and educational intervention, sources of information, knowledge, attitude, and preventive practice regarding dengue fever. The results of this study showed that most of the respondents have moderate knowledge level, positive attitude, and fair preventive practices. Preventive practice has a significant relationship with barangay, family income, health promotional activities and educational intervention, and received information. A structural equation model was developed, tested and fitted to the data well (chi-square= 81.960, df= 52, CFI= .947, TLI=.933, and RMSEA= .037). Furthermore, a positive attitude towards dengue fever had a positive impact on the dengue preventive practice of the residents in Dasmariñas, however high knowledge about dengue fever does not guarantee good practice of preventive measures

Mitochondrial respiratory capacity is a critical regulator of CD8⁺ T cell memory development

CD8+ T cells undergo major metabolic changes upon activation, but how metabolism influences the establishment of long-lived memory T cells after infection remains a key question. We have shown here that CD8+ memory T cells, but not CD8+ T effector (Teff) cells, possessed substantial mitochondrial spare respiratory capacity (SRC). SRC is the extra capacity available in cells to produce energy in response to increased stress or work and as such is associated with cellular survival. We found that interleukin-15 (IL-15), a cytokine critical for CD8+ memory T cells, regulated SRC and oxidative metabolism by promoting mitochondrial biogenesis and expression of carnitine palmitoyl transferase (CPT1a), a metabolic enzyme that controls the rate-limiting step to mitochondrial fatty acid oxidation (FAO). These results show how cytokines control the bioenergetic stability of memory T cells after infection by regulating mitochondrial metabolism

Commitment to glycolysis sustains survival of NO-producing inflammatory dendritic cells

TLR agonists initiate a rapid activation program in dendritic cells (DCs) that requires support from metabolic and bioenergetic resources. We found previously that TLR signaling promotes aerobic glycolysis and a decline in oxidative phosphorylation (OXHPOS) and that glucose restriction prevents activation and leads to premature cell death. However, it remained unclear why the decrease in OXPHOS occurs under these circumstances. Using real-time metabolic flux analysis, in the present study, we show that mitochondrial activity is lost progressively after activation by TLR agonists in inflammatory blood monocyte–derived DCs that express inducible NO synthase. We found that this is because of inhibition of OXPHOS by NO and that the switch to glycolysis is a survival response that serves to maintain ATP levels when OXPHOS is inhibited. Our data identify NO as a profound metabolic regulator in inflammatory monocyte–derived DCs

Fatty acid oxidation is essential for egg production by the parasitic flatworm Schistosoma mansoni

Schistosomes, parasitic flatworms that cause the neglected tropical disease schistosomiasis, have been considered to have an entirely carbohydrate based metabolism, with glycolysis playing a dominant role in the adult parasites. However, we have discovered a close link between mitochondrial oxygen consumption by female schistosomes and their ability to produce eggs. We show that oxygen consumption rates (OCR) and egg production are significantly diminished by pharmacologic inhibition of carnitine palmitoyl transferase 1 (CPT1), which catalyzes a rate limiting step in fatty acid β-oxidation (FAO) and by genetic loss of function of acyl CoA synthetase, which complexes with CPT1 and activates long chain FA for use in FAO, and of acyl CoA dehydrogenase, which catalyzes the first step in FAO within mitochondria. Declines in OCR and egg production correlate with changes in a network of lipid droplets within cells in a specialized reproductive organ, the vitellarium. Our data point to the importance of regulated lipid stores and FAO for the compartmentalized process of egg production in schistosomes

Lhx3, a LIM domain transcription factor, is regulated by Pou4f3 in the auditory but not in the vestibular system

A dominant mutation of the gene encoding the POU4F3 transcription factor underlies human non-syndromic progressive hearing loss DFNA15. Using oligonucleotide microarrays to generate expression profiles of inner ears of Pou4f3 ddl/ ddl mutant and wild-type mice, we have identified and validated Lhx3, a LIM domain transcription factor, as an in vivo target gene regulated by Pou4f3. Lhx3 is a hair cell-specific gene expressed in all hair cells of the auditory and vestibular system as early as embryonic day 16. The level of Lhx3 mRNA is greatly reduced in the inner ears of embryonic Pou4f3 mutant mice. Our data also show that the expression of Lhx3 is regulated differently in auditory and vestibular hair cells. This is the first example of a hair cell-specific gene expressed both in auditory and in vestibular hair cells, with differential regulation of expression in these two closely related systems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72019/1/j.1460-9568.2007.05332.x.pd