Contribution to the Analysis, Design and Assessment of Compact Antenna Test Ranges At Millimeter Wavelengths - Contribución al Análisis, Diseño y Caracterización de Sistemas de Medida de Antenas en Rango Compacto para Frecuencias Milimétricas

This Doctoral Thesis entitled Contribution to the analysis, design and assessment of compact antenna test ranges at millimeter wavelengths aims to deepen the knowledge of a particular antenna measurement system: the compact range, operating in the frequency bands of millimeter wavelengths. The thesis has been developed at Radiation Group (GR), an antenna laboratory which belongs to the Signals, Systems and Radiocommunications department (SSR), from Technical University of Madrid (UPM). The Radiation Group owns an extensive experience on antenna measurements, running at present four facilities which operate in different configurations: Gregorian compact antenna test range, spherical near field, planar near field and semianechoic arch system. The research work performed in line with this thesis contributes the knowledge of the first measurement configuration at higher frequencies, beyond the microwaves region where Radiation Group features customer-level performance. To reach this high level purpose, a set of scientific tasks were sequentially carried out. Those are succinctly described in the subsequent paragraphs. A first step dealed with the State of Art review. The study of scientific literature dealed with the analysis of measurement practices in compact antenna test ranges in addition with the particularities of millimeter wavelength technologies. Joint study of both fields of knowledge converged, when this measurement facilities are of interest, in a series of technological challenges which become serious bottlenecks at different stages: analysis, design and assessment. Thirdly after the overview study, focus was set on Electromagnetic analysis algorithms. These formulations allow to approach certain electromagnetic features of interest, such as field distribution phase or stray signal analysis of particular structures when they interact with electromagnetic waves sources. Properly operated, a CATR facility features electromagnetic waves collimation optics which are large, in terms of wavelengths. Accordingly, the electromagnetic analysis tasks introduce an extense number of mathematic unknowns which grow with frequency, following different polynomic order laws depending on the used algorithmia. In particular, the optics configuration which was of our interest consisted on the reflection type serrated edge collimator. The analysis of these devices requires a flexible handling of almost arbitrary scattering geometries, becoming this flexibility the nucleus of the algorithmia’s ability to perform the subsequent design tasks. This thesis’ contribution to this field of knowledge consisted on reaching a formulation which was powerful at the same time when dealing with various analysis geometries and computationally speaking. Two algorithmia were developed. While based on the same principle of hybridization, they reached different order Physics performance at the cost of the computational efficiency. Inter-comparison of their CATR design capabilities was performed, reaching both qualitative as well as quantitative conclusions on their scope. In third place, interest was shifted from analysis - design tasks towards range assessment. Millimetre wavelengths imply strict mechanical tolerances and fine setup adjustment. In addition, the large number of unknowns issue already faced in the analysis stage appears as well in the on chamber field probing stage. Natural decrease of dynamic range available by semiconductor millimeter waves sources requires in addition larger integration times at each probing point. These peculiarities increase exponentially the difficulty of performing assessment processes in CATR facilities beyond microwaves. The bottleneck becomes so tight that it compromises the range characterization beyond a certain limit frequency which typically lies on the lowest segment of millimeter wavelength frequencies. However the value of range assessment moves, on the contrary, towards the highest segment. This thesis contributes this technological scenario developing quiet zone probing techniques which achieves substantial data reduction ratii. Collaterally, it increases the robustness of the results to noise, which is a virtual rise of the setup’s available dynamic range. In fourth place, the environmental sensitivity of millimeter wavelengths issue was approached. It is well known the drifts of electromagnetic experiments due to the dependance of the re sults with respect to the surrounding environment. This feature relegates many industrial practices of microwave frequencies to the experimental stage, at millimeter wavelengths. In particular, evolution of the atmosphere within acceptable conditioning bounds redounds in drift phenomena which completely mask the experimental results. The contribution of this thesis on this aspect consists on modeling electrically the indoor atmosphere existing in a CATR, as a function of environmental variables which affect the range’s performance. A simple model was developed, being able to handle high level phenomena, such as feed - probe phase drift as a function of low level magnitudes easy to be sampled: relative humidity and temperature. With this model, environmental compensation can be performed and chamber conditioning is automatically extended towards higher frequencies. Therefore, the purpose of this thesis is to go further into the knowledge of millimetre wavelengths involving compact antenna test ranges. This knowledge is dosified through the sequential stages of a CATR conception, form early low level electromagnetic analysis towards the assessment of an operative facility, stages for each one of which nowadays bottleneck phenomena exist and seriously compromise the antenna measurement practices at millimeter wavelengths.

STC power for 15MW of PV comparing nameplate, initial power and power after 4 years

To date, the majority of quality controls performed at PV plants are based on the measurement of a small sample of individual modules. Consequently, there is very little representative data on the real Standard Test Conditions (STC) power output values for PV generators. This paper presents the power output values for more than 1300 PV generators having a total installed power capacity of almost 15.3 MW. The values were obtained by the INGEPER-UPNA group, in collaboration with the IES-UPM, through a study to monitor the power output of a number of PV plants from 2006 to 2009. This work has made it possible to determine, amongst other things, the power dispersion that can be expected amongst generators made by different manufacturers, amongst generators made by the same manufacturer but comprising modules of different nameplate ratings and also amongst generators formed by modules with the same characteristics. The work also analyses the STC power output evolution over time in the course of this 4-year study. The values presented here could be considered to be representative of generators with fault-free modules.

Bankable procedures for the technical quality assurance of large scale PV plants

Strict technical quality assurance procedures are essential for PV plant bankability. When large-scale PV plants are concerned, this is typically accomplished in three consecutive phases: an energy yield forecast, that is performed at the beginning of the project and is typically accomplished by means of a simulation exercise performed with dedicated software; a reception test campaign, that is performed at the end of the commissioning and consists of a set of tests for determining the efficiency and the reliability of the PV plant devices; and a performance analysis of the first years of operation, that consists in comparing the real energy production with the one calculated from the recorded operating conditions and taking into account the maintenance records. In the last six years, IES-UPM has offered both indoor and on-site quality control campaigns for more than 60 PV plants, with an accumulated power of more than 300 MW, in close contact with Engineering, Procurement and Construction Contractors and financial entities. This paper presents the lessons learned from such experience.

An accurate model for simulating energetic behavior of PV grid connected inverters

This paper proposes a new model for characterizing the energetic behavior of grid connected PV inverters. The model has been obtained from a detailed study of main loss processes in small size PV inverters in the market. The main advantage of the used method is to obtain a model that comprises two antagonistic features, since both are simple, easy to compute and apply, and accurate. One of the main features of this model is how it handles the maximum power point tracking (MPPT) and the efficiency: in both parts the model uses the same approach and it is achieved by two resistive elements which simulate the losses inherent to each parameter. This makes this model easy to implement, compact and refined. The model presented here also includes other parameters, such as start threshold, standby consumption and islanding behavior. In order to validate the model, the values of all the parameters listed above have been obtained and adjusted using field measurements for several commercial inverters, and the behavior of the model applied to a particular inverter has been compared with real data under different working conditions, taken from a facility located in Madrid. The results show a good fit between the model values and the real data. As an example, the model has been implemented in PSPICE electronic simulator, and this approach has been used to teach grid-connected PV systems. The use of this model for the maintenance of working PV facilities is also shown.

Toward a consolidation of the CPV-specific-test procedures for inverters

The inverter in a photovoltaic system assures two essential functions. The first is to track the maximum power point of the system IV curve throughout variable environmental conditions. The second is to convert DC power delivered by the PV panels into AC power. Nowadays, in order to qualify inverters, manufacturers and certifying organisms use mainly European and/or CEC efficiency standards. The question arises if these are still representative of CPV system behaviour. We propose to use a set of CPV – specific weighted average and a representative dynamic response to have a better determination of the static and dynamic MPPT efficiencies. Four string-sized commercial inverters used in real CPV plants have been tested.

Avaliação do desempenho do sistema de mini-geração fotovoltaico na Faculdade de Ciências

Tese de mestrado integrado, Engenharia da Energia e do Ambiente, Universidade de Lisboa, Faculdade de Ciências, 2016

Experimenter effects on behavioral test scores of eight inbred mouse strains under the influence of ethanol.

ight standard inbred mouse strains were evaluated for ethanol effects on a refined battery of behavioral tests in a study that was originally designed to assess the influence of rat odors in the colony on mouse behaviors. As part of the design of the study, two experimenters conducted the tests, and the study was carefully balanced so that equal numbers of mice in all groups and times of day were tested by each experimenter. A defect in airflow in the facility compromised the odor manipulation, and in fact the different odor exposure groups did not differ in their behaviors. The two experimenters, however, obtained markedly different results for three of the tests. Certain of the experimenter effects arose from the way they judged behaviors that were not automated and had to be rated by the experimenter, such as slips on the balance beam. Others were not evident prior to ethanol injection but had a major influence after the injection. For several measures, the experimenter effects were notably different for different inbred strains. Methods to evaluate and reduce the impact of experimenter effects in future research are discussed.

The impact of the juvenile intervention facility on the adjudication of delinquent youth in Broward County

Considerable funds have been allocated in the area of juvenile justice in attempts to reduce and prevent the problem of juvenile delinquency. Much of these funds have been funneled to various community-level intervention programs. This dissertation reports the results of a study that examined the effects of one such program, the Juvenile Intervention Facility (JIF) in Broward County, Florida, on reducing the number of cases handled judicially by the Juvenile Court in that county. ^ Juvenile justice policy, which precipitated the creation of the JIF program, assumed that more structured and integrative efforts at the point of entry into the juvenile justice system would lead to greater diversion from the courts to much needed intervention services. By virtue of this process, the number of juveniles handled judicially by the courts was expected to decrease and future delinquent behavior would be prevented. Archival data from four fiscal years were examined, two years pre-JIF, two years post-JIF, a third-year follow-up, and a concurrent outcome measure corresponding to the first year of JIF operations. Data included all juvenile cases referred during the fiscal years defined for Broward and St. Lucie Counties, the state of Florida, and the United States. The study tested four hypotheses: (a) the JIF would reduce the number of cases handled judicially in Broward County Juvenile Court, (b) the decrease in judicially handled cases would be greater for females than for males, (c) there would be greater decreases in judicially handled cases for whites than non-whites, (d) there would be greater decreases in judicial handling for younger than older offenders. Bivariate analyses were conducted, consisting of chi square tests, to test the hypotheses. ^ Results indicate that the impact of the JIF was in the opposite direction of what was expected in that more juvenile offenders were handled judicially through juvenile court. This fact points to the possibility that the JIF has failed to provide the intended consequences of the policy. In the discussion, these “unintended” consequences are addressed in the context of juvenile justice policy creation and the competing constituencies involved in such policy development. ^

The politics of professional sports facility subsidies in Florida

Political leaders in urban settings regularly confront difficult decisions over how to distribute public funds. Those decisions may be even more controversial when they involve public subsidies of professional sports facilities. Yet, state and local governments in the United States have granted billions of dollars in financial and land-based subsidies for professional sports facilities over the past two decades, raising questions about how these types of corporate welfare decisions are made by local leaders. Scholarship on urban politics and community power suggests a number of theories to explain political influence. They include elitism, pluralism, political economy and growth machines, urban regimes, coalition theory, and minority empowerment. My hypothesis is that coalition theory, a theory that argues that public policy decisions are made by shifting, ad hoc alliances within a community, best describes these subsidy decisions. ^ To test this hypothesis I employ a public policy process model and develop a framework of variables that is used to methodically examine four sports facilities funding decisions in two Florida counties between 1977 and 1998: Joe Robbie Stadium and the American Airlines Arena in Miami-Dade, and the Ice Palace Arena and the Raymond James Stadium in Hillsborough County. The framework includes six variables that permit a rigorous examination of the actors involved in the decision, their interactions, and the political environment within which they operate. The variables are formal political structure, informal sector, subsidy proponents, subsidy opponents, public policy options, and public opinion. ^ This research rests on qualitative data gathered from interviews of public and private officials involved in subsidy decisions, public records, and media reports Employing a case study analysis, I offer a rich description of the decision making process to publicly fund sports stadiums and arenas in Florida. My findings confirm that the best theory to explain decisions to subsidize sports facilities is one in which short-term, temporary coalitions are formed to accomplish policy goals. ^

Development of test-based wind-driven rain intrusion model for hurricane-induced building interior and contents damage

Major portion of hurricane-induced economic loss originates from damages to building structures. The damages on building structures are typically grouped into three main categories: exterior, interior, and contents damage. Although the latter two types of damages, in most cases, cause more than 50% of the total loss, little has been done to investigate the physical damage process and unveil the interdependence of interior damage parameters. Building interior and contents damages are mainly due to wind-driven rain (WDR) intrusion through building envelope defects, breaches, and other functional openings. The limitation of research works and subsequent knowledge gaps, are in most part due to the complexity of damage phenomena during hurricanes and lack of established measurement methodologies to quantify rainwater intrusion. This dissertation focuses on devising methodologies for large-scale experimental simulation of tropical cyclone WDR and measurements of rainwater intrusion to acquire benchmark test-based data for the development of hurricane-induced building interior and contents damage model. Target WDR parameters derived from tropical cyclone rainfall data were used to simulate the WDR characteristics at the Wall of Wind (WOW) facility. The proposed WDR simulation methodology presents detailed procedures for selection of type and number of nozzles formulated based on tropical cyclone WDR study. The simulated WDR was later used to experimentally investigate the mechanisms of rainwater deposition/intrusion in buildings. Test-based dataset of two rainwater intrusion parameters that quantify the distribution of direct impinging raindrops and surface runoff rainwater over building surface — rain admittance factor (RAF) and surface runoff coefficient (SRC), respectively —were developed using common shapes of low-rise buildings. The dataset was applied to a newly formulated WDR estimation model to predict the volume of rainwater ingress through envelope openings such as wall and roof deck breaches and window sill cracks. The validation of the new model using experimental data indicated reasonable estimation of rainwater ingress through envelope defects and breaches during tropical cyclones. The WDR estimation model and experimental dataset of WDR parameters developed in this dissertation work can be used to enhance the prediction capabilities of existing interior damage models such as the Florida Public Hurricane Loss Model (FPHLM).^

Robustness in facility location

Facility location concerns the placement of facilities, for various objectives, by use of mathematical models and solution procedures. Almost all facility location models that can be found in literature are based on minimizing costs or maximizing cover, to cover as much demand as possible. These models are quite efficient for finding an optimal location for a new facility for a particular data set, which is considered to be constant and known in advance. In a real world situation, input data like demand and travelling costs are not fixed, nor known in advance. This uncertainty and uncontrollability can lead to unacceptable losses or even bankruptcy. A way of dealing with these factors is robustness modelling. A robust facility location model aims to locate a facility that stays within predefined limits for all expectable circumstances as good as possible. The deviation robustness concept is used as basis to develop a new competitive deviation robustness model. The competition is modelled with a Huff based model, which calculates the market share of the new facility. Robustness in this model is defined as the ability of a facility location to capture a minimum market share, despite variations in demand. A test case is developed by which algorithms can be tested on their ability to solve robust facility location models. Four stochastic optimization algorithms are considered from which Simulated Annealing turned out to be the most appropriate. The test case is slightly modified for a competitive market situation. With the Simulated Annealing algorithm, the developed competitive deviation model is solved, for three considered norms of deviation. At the end, also a grid search is performed to illustrate the landscape of the objective function of the competitive deviation model. The model appears to be multimodal and seems to be challenging for further research.

Prevalence of diabetic retinopathy in type II diabetic patients in a health facility in Karachi, Pakistan

Purpose: To study the prevalence of diabetic retinopathy in known diabetic patients attending the diabetes outpatient department (OPD) of Sind Government Hospital (SGH), New Karachi Township (NKT), Pakistan. Methods: A cross-sectional observational study was carried out at the diabetic OPD of SGH, NKT over the period of 17 months from March 2013 to August 2014. The selected patients were interviewed based on a questionnaire; laboratory investigations were performed and examination of the eye was conducted by a specialist ophthalmologist. One hundred and fifty four (154) subjects out of 305 patients contacted fully completed the study. Stratification of the data on gender basis was done, after which one-way ANOVA, χ2 test of correlation, binary logistic regression and relative risk analyses were carried out using SPSS-20. Results: It was found that 66 % men of normal weight (χ2 = 4.667, p < 0.05) and 60.7 % overweight women (χ2 = 5.143, p < 0.05) were more likely to present with diabetic retinopathy (DR). Prevalence of DR in this target population was 42.86 % (N = 66). Background DR (56 %) and maculopathy (23 %) were more prevalent than advanced conditions of the disease. There was no gender-based preponderance for the presentation of DR (χ2 = 0.663; p > 0.05), nor was this seen in different ethnic groups. Conclusion: DR is prevalent in the target population and, therefore, emphasis should be on the education of the local population of New Karachi Township on how to attain euglycemic state with regular medication, diet and exercise to avoid development and progress of DR.

Gender-specific association of MSA2756G with hypertension in patients attending a health facility in Ningxia Province, China

Purpose: To investigate the distribution of methionine synthase A2756G (MSA2756G) in the hypertensive patients in northwest Chinese population. Methods: A total of 378 unrelated hypertensive patients attending Ningxia Peoples Hospital, Ningxia Province, China, were recruited for this study. We analyzed genotype by amplication - created restriction sites (ACRS) and polymerase chain reaction - restrict fragment length polymorphism (PCR - RFLP) in hypertensive patients, and inspected the relation of the genotype with hypertension by χ2 and t test. Results: The frequency of G allele was 10.25 % in the control group and 14.04 % in hypertension group; it was not statistically different (p > 0.05). In the male group, the frequency of allele G was 11.50 % in control group, and 8.79 % in hypertension group. There was no significant difference between control and hypertension groups (p > 0.05). In the female group, the frequency of allele G was 9.00 %, in control and 19.54 % in hypertension group (p < 0.05), while in the hypertension group, allele G was 8.79 % in males which is significantly lower (p < 0.05) than in females (19.54 %) . Conclusion: Allele G of MSA2756G is a risk factor for hypertension in female in this Chinese population of this study.