Innovative Thermal Management Systems for Autonomous Vehicles — Design, Model, and Test

Emphasis on reducing fossil fuel consumption and greenhouse gas emissions, besides the demand for autonomy in vehicles, made governments and automotive industries move towards electrification. The integration of an electric motor with battery packs and on-board electronics has created new thermal challenges due to the heat loads\u27 operating conditions, design configurations, and heat generation rates. This paradigm shift necessitates an innovative thermal management system that can accommodate low, moderate, and high heat dissipations with minimal electrical or mechanical power requirements. This dissertation proposes an advanced hybrid cooling system featuring passive and active cooling solutions in a thermal bus configuration. The main purpose is to maintain the heat loads’ operating temperatures with zero to minimum power requirements and improved packaging, durability, and reliability. In many operating instances, a passive approach may be adequate to remove heat from the thermal source (e.g., electric motor) while a heavy load would demand both the passive and active cooling systems operate together for reduced electric power consumption. Further, in the event of a failure (e.g., coolant hose leak, radiator tube leak) in the conventional system, the passive system offers a redundant operating mode for continued operation at reduced loads. Besides, the minimization of required convective heat transfer (e.g., ram air effect) about the components for supplemental cooling enables creative vehicle component placement options and optimizations. Throughout this research, several cooling system architectures are introduced for electric vehicle thermal management. Each design is followed by a mathematical model that evaluates the steady-state and transient thermal responses of the integrated heat load(s) and the developed cooling system. The designs and the mathematical models are then validated through a series of thermal tests for a variety of driving cycles. Then, the cooling system design configuration is optimized using the validated mathematical model for a particular application. The nonlinear optimization study demonstrates that a 50\% mass reduction could be achieved for a continuous 12kW heat-dissipating demand while the electric motor operating temperature has remained below 65 centigrade degrees. Next, several real-time controllers are designed to engage the active cooling system for precise, stable, and predictable temperature regulation of the electric motor and reduced power consumption. A complete experimental setup compares the controllers in the laboratory’s environment. The experimental results indicate that the nonlinear model predictive control reduces the fan power consumption by 73% for a 5% increase in the pump power usage compared to classical control for a specific 60-minute driving cycle. In conclusion, the conducted experimental and numerical studies demonstrate that the proposed hybrid cooling strategy is an effective solution for the next generation of electrified civilian and combat ground vehicles. It significantly reduces the reliance on fossil fuels and increases vehicle range and safety while offering a silent mode of operation. Future work is to implement the developed hybrid cooling system on an actual electric vehicle, validate the design, and identify challenges on the road

EXPERIMENTAL INVESTIGATION OF HEAT LEAKAGE AND AIR LEAKAGE IN DOMESTIC REFRIGERATORS

The optimization of the energy consumption in household refrigerators should consider the influence of the gasket which determines the heat transfer and air infiltration rate. In this research project, engineering methods are developed to evaluate the heat leakage due to the gasket and air infiltration in domestic refrigerators. In the first study, experimental and numerical approaches are applied to evaluate the gasket heat transfer based on the “Reverse Heat Load Methodâ€. The main objective is to find the effective heat leakage with the dimensions of energy leakage per gasket length per temperature difference (W/m.K). An insulated cubic box with a 216,000 〖cm〗^3 interior enclosure (60cm x 60cm x 60cm) was designed to accept a matching set of adjoining refrigerator door and wall cuts placed inside the cavity. The door and walls are surrounded by thick insulation material so that only the gasket region is exposed to the ambient environment. A heat source was placed inside the center of the box to create a desired temperature difference between the interior and the ambient. Thermocouples measured the interior and ambient temperatures while six heat flux sensors, mounted on the exposed gasket region, measured the heat flux exiting the box through this region. Two restrictions were imposed with the heat flux sensors to evaluate the heat leakage purely experimentally. The heat flux sensors did not offer sufficient resolution to fully resolve the surface heat flux distribution, and they were incapable of directly measuring the heat flux leaving through the gasket due to its complex geometry. Therefore, Computational Fluid Dynamics (CFD) simulations were necessary to complete the heat flux profile between the experimental data points recorded by the sensor). Accordingly, a two dimensional (2D) simulation was performed to provide a shape profile of the heat flux leaving the gasket region which may be used to fit the experimental data using a “Least Mean Square Error†approach. The estimated heat loss at the gasket region with the original gasket installed on the sample refrigerator was 0.20 W/m.K. Extensive testing with other gaskets showed that their design and materials influenced the heat loss of the refrigerator. The second study developed a methodology to identify the leaks, to estimate the air infiltration rate, and to calculate the energy loss associated with air leaks in domestic refrigerators. The water drain tube was determined to be the primary air leak source due to the presence of the evaporator fan inside the freezer compartment. In addition, many other leaks with unknown sizes were found through bubble tests about the cabinet. Two identical refrigerators were employed to evaluate the impact of the air loads. One refrigerator remained with its original conditions and the other unit was completely sealed so that there existed a single inlet (water drain tube) and a single outlet (a drilled hole). The intact refrigerator was used to measure the normal operating conditions with respect to the ambient environment (e.g. pressure and temperature differences) to mimic these conditions in the sealed unit. The sealed unit had a hole drilled into the cabinet and the water drain tube remained open to the ambient. The size of the drilled hole was adjusted until the same pressure difference was achieved on the new unit at the same temperature difference. A flow meter measured the air flow through the hole and thermocouples measured the ambient and interior temperatures simultaneously. The energy leakage due to the air infiltration was calculated using the first law of thermodynamics based on two temperatures and mass flow rates at the inlet and outlet. The actual air infiltration rate was measured and the effective heat transfer rate due to the air infiltration rate was calculated 4.4 Watts. Modeling shows that refrigerators are not under steady state operation. They “breathe†drawing air in during cooling and forcing air out during warming between compressor cycles. A hypothetical perfectly sealed unit is shown to produce forces upwards of 350 lbf on the fresh food door due to this effect alone

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An Analysis of the Investment Decisions on the European Electricity Markets, over the 1945-2013 Period

12 pagesThe aim of the article is to understand how the drivers for investment decisions in the capacities of electricity production have evolved over time, from 1945 to the present day, in the specific context of Europe facing wars and conflicts, scientific and technological progress, strong political and academic developments. We study the electric investment decisions by comparing the history of the European electricity markets with the successively dominant economic theories in this field. Therefore, we highlight differences between rational behaviors, such as described by the theories, and actual behaviors of investors and governments. Thus the liberalization of electricity markets in the European Union, more than twenty-five years ago, parts of a rationalization prescribed by new economic theories. It is clear that liberalization is being discussed. First, it remains very heterogeneous, which complicates the goal of creating a large single market for electricity in the Union. Second, we see a recent re-centralization of energy policy in the European Union (EU), which takes the form of a new regulation mainly relating to climate and renewables. However, this re-regulation is different from centralized control experienced by all European electricity markets until the mid-1980s

Dialogue between organizations and publics in the digital era: the “unfulfilled promise” of new media and the consultancy discourse in Spain

The expansion of digital communication technologies has been accompanied by the development of a “dialogical theory” of Public Relations, a theory that saw in new media the potential to implement ethical principles about dialogue to communications between organizations and publics. This article studies the current situation of the subject from two points of view: a critical literature review and discourse analysis of the 40 largest public relations consulting companies in Spain. As a result of the first component, “the unfulfilled promise” of the new media is highlighted. The analysis of the consulting discourse, on the other hand, shows the preference given to conversation and engagement as alternative concepts, the persistence of the discursive connection between digital technology and dialogic processes, as well as the existence of three basic forms this connection assumes. Theoretical and practical implications of these results are discussed

Alcance y potencialidad cognoscitiva del lenguaje metafórico en el estudio de la opinión pública

Esta tesis parte por presentar la importancia de las metáforas en el conocimiento y, sobre esta base, identifica metáforas centrales en el campo de la opinión pública, describe el alcance que tienen estas figuras en la caracterización de las áreas temáticas fundamentales de este campo y, finalmente, ofrece una serie de pautas para un uso deliberado y sistemático de las metáforas en el desarrollo cognoscitivo sobre el tema. Para ello, desarrolla un modelo de análisis formado por tres elementos: la delimitación de un corpus de estudio constituido por seis obras de referencia clave en la opinión pública, la identificación de las áreas temáticas fundamentales que componen este campo (definición, historia, dinámica, política, medios e investigación) y el establecimiento de criterios para identificar metáforas, describirlas y determinar su alcance epistémico dentro de las teorías a través de un análisis del discurso.Como resultado, se observa que cada obra se apoya en una metáfora central o dos metáforas mutuamente complementarias: la “imagen” y el “estereotipo” (Walter Lippmann), la “vida” y la “máquina” (John Dewey), el “espacio” y la “esfera” (Jürgen Habermas), la “agenda” (Maxwell McCombs) la “piel” y el “clima” (Elisabeth Noelle-Neumann) y la “red informática” (Manuel Castells). Para mostrar la importancia epistémica de estas metáforas en cada perspectiva teórica —y en cada área temática de la opinión pública— se reconstruyen los discursos a través de textos que relacionan los argumentos de cada autor con el uso de dichos recursos figurados del lenguaje. Por otra parte, aplicando investigaciones disponibles sobre el papel de la metáfora en el desarrollo cognitivo, se establecen y ejemplifican tres pasos para el uso del lenguaje metafórico en el avance del conocimiento sobre la opinión pública: identificación de anomalías, presentación de metáforas y generación de experiencias. Además, se presenta la potencialidad cognitiva que supone la interacción entre diferentes metáforas como parte del mencionado proceso. Finalmente, se exploran consecuencias de estos hallazgos para el campo de la opinión pública

Geographical distribution of host's specific SARS-CoV-2 mutations in the early phase of the COVID-19 pandemic

PURPOSE: To assess, if the SARS-CoV-2 mutate in a similar pattern globally or has a specific pattern in any given population. RESULTS: We report, the insertion of TTT at 11085, which adds an extra amino acid, F to the NSP6 at amino acid position 38. The highest occurrence of TTT insertion at 11,085 position was found in UK derived samples (65.97%). The second and third highest occurrence of the mutation were found in Australia (8.3%) and USA (4.16%) derived samples, respectively. Another important discovery of this study is the C27945T mutation, which translates into the termination of ORF-8 after 17 amino acids, reveals that the SARS-CoV-2 can replicate without the intact ORF-8 protein. We found that the 97% of C27945T mutation of global occurrence, occurred in Europe and the USA derived samples. CONCLUSION: Two of the reported mutations (11085TTT insertion and C27945T nonsense), which seemed to reduce Type I interferon response are linked to specific geographical locations of the host and implicate region-specific mutations in the virus. The findings of this study signify that SARS-CoV-2 has the potential to adapt differently to different populations

Genetic effects on longitudinal cognitive decline during the early stages of Alzheimer's disease

Cognitive decline in early-stage Alzheimer’s disease (AD) may depend on genetic variability. In the Swedish BioFINDER study, we used polygenic scores (PGS) (for AD, intelligence, and educational attainment) to predict longitudinal cognitive change (measured by mini-mental state examination (MMSE) [primary outcome] and other cognitive tests) over a mean of 4.2 years. We included 260 β-amyloid (Aβ) negative cognitively unimpaired (CU) individuals, 121 Aβ-positive CU (preclinical AD), 50 Aβ-negative mild cognitive impairment (MCI) patients, and 127 Aβ-positive MCI patients (prodromal AD). Statistical significance was determined at Bonferroni corrected p value < 0.05. The PGS for intelligence (beta = 0.1, p = 2.9e−02) was protective against decline in MMSE in CU and MCI participants regardless of Aβ status. The polygenic risk score for AD (beta = − 0.12, p = 9.4e−03) was correlated with the rate of change in MMSE and was partially mediated by Aβ-pathology (mediation effect 20%). There was no effect of education PGS on cognitive measures. Genetic variants associated with intelligence mitigate cognitive decline independent of Aβ-pathology, while effects of genetic variants associated with AD are partly mediated by Aβ-pathology

A comprehensive analysis of methods for assessing polygenic burden on Alzheimer’s disease pathology and risk beyond APOE

Genome-wide association studies have identified dozens of loci that alter the risk to develop Alzheimer’s disease. However, with the exception of the APOE-ε4 allele, most variants bear only little individual effect and have, therefore, limited diagnostic and prognostic value. Polygenic risk scores aim to collate the disease risk distributed across the genome in a single score. Recent works have demonstrated that polygenic risk scores designed for Alzheimer’s disease are predictive of clinical diagnosis, pathology confirmed diagnosis and changes in imaging biomarkers. Methodological innovations in polygenic risk modelling include the polygenic hazard score, which derives effect estimates for individual single nucleotide polymorphisms from survival analysis, and methods that account for linkage disequilibrium between genomic loci. In this work, using data from the Alzheimer’s disease neuroimaging initiative, we compared different approaches to quantify polygenic disease burden for Alzheimer’s disease and their association (beyond the APOE locus) with a broad range of Alzheimer’s disease-related traits: cross-sectional CSF biomarker levels, cross-sectional cortical amyloid burden, clinical diagnosis, clinical progression, longitudinal loss of grey matter and longitudinal decline in cognitive function. We found that polygenic scores were associated beyond APOE with clinical diagnosis, CSF-tau levels and, to a minor degree, with progressive atrophy. However, for many other tested traits such as clinical disease progression, CSF amyloid, cognitive decline and cortical amyloid load, the additional effects of polygenic burden beyond APOE were of minor nature. Overall, polygenic risk scores and the polygenic hazard score performed equally and given the ease with which polygenic risk scores can be derived; they constitute the more practical choice in comparison with polygenic hazard scores. Furthermore, our results demonstrate that incomplete adjustment for the APOE locus, i.e. only adjusting for APOE-ε4 carrier status, can lead to overestimated effects of polygenic scores due to APOE-ε4 homozygous participants. Lastly, on many of the tested traits, the major driving factor remained the APOE locus, with the exception of quantitative CSF-tau and p-tau measures

The importance of small non-coding RNAs in human reproduction: A review article

Background: MicroRNAs (miRNA) play a key role in the regulation of gene expression through the translational suppression and control of post-transcriptional modifications. Aim: Previous studies demonstrated that miRNAs conduct the pathways involved in human reproduction including maintenance of primordial germ cells (PGCs), spermatogenesis, oocyte maturation, folliculogenesis and corpus luteum function. The association of miRNA expression with infertility, polycystic ovary syndrome (PCOS), premature ovarian failure (POF), and repeated implantation failure (RIF) was previously revealed. Furthermore, there are evidences of the importance of miRNAs in embryonic development and implantation. Piwi-interacting RNAs (piRNAs) and miRNAs play an important role in the post-transcriptional regulatory processes of germ cells. Indeed, the investigation of small RNAs including miRNAs and piRNAs increase our understanding of the mechanisms involved in fertility. In this review, the current knowledge of microRNAs in embryogenesis and fertility is discussed. Conclusion: Further research is necessary to provide new insights into the application of small RNAs in the diagnosis and therapeutic approaches to infertility