A MANUFACTURING PROCESS TO IMPLEMENT TRANSONIC COMPRESSOR ENDWALL CASING TREATMENTS

The goal of this thesis is to create a manufacturing process that will be used to implement transonic compressor treatments in the form of grooves or passages beneath the endwall surface. The main goal of the treatments are to extend the stability margin of the gas turbine engine without significantly harming its efficiency. This is done by redirecting flow to the axial direction near stall or by hindering the formation of harmful flow features such as the tip leakage vortex. The specific geometries of the treatments are based on empirical and experimental data previously collected in other studies. Implementing treatments was done by casting the desired geometry into a layer of epoxy on the endwall surface, using molds and attachments made by additive manufacturing. It was found that using water soluble molds was a necessary feature of surface treatment molds in epoxy. The same material was used to mold internal passages that would be used to recirculate high pressure air from behind the rotor to the low pressure region upstream of the rotor. Fanno flow calculations provided a way to determine the mass flow rate through a single passage, and therefore how many passages of a specific size and shape would be needed to recirculate a certain percentage of mass flow through the compressor. By keeping the passages within the epoxy layer, the inner diameter of the casing was only increased by about 2 percent.Outstanding ThesisEnsign, United States NavyApproved for public release. Distribution is unlimited

Requirements degradation for the creation of a first prototype

The requirements engineering process is typically executed, irrespective of the process model chosen, for the final commercially viable system. The system requirements generated are for a system deployed and used in its final form and function. However, the first prototype that is generated is typically representative of a minimum viable technology, and represents a degraded set of the initial system requirements specification. Typically, a first prototype is used as a technology demonstrator, and its failure or success will determine the continuation of the project, with success triggering the allocation of additional financial and personal resources. This paper explores techniques for requirements degradation that can be used to form the system requirements specification for the first prototype. A requirements Engineering methodology is proposed based upon a survey of literature. It takes into consideration the characteristics of the project, i.e. a market driven, technology implementation research project with limited budget and a flexible timeline executed in an academic environment. The techniques must take into cognizance the main risk items, and core requirements, that need to be demonstrated in the minimum viable technology to secure the future of the project. The degradation cannot undermine or jeopardize the future success of the commercially viable system in determining the subset of requirements for the minimum viable technology

Peace in Guatemala and Immigrant Health in the United States

Background: The civil war between the indigenous Mayans and other Guatemalans lasted for 36 years, killed civilians, decimated villages, and resulted in many refugees. The Guatemalan Peace Agreement of 1996 aimed to alleviate the ongoing conflict. Studies of peace agreements more typically evaluate local political outcomes while neglecting global health outcomes. Objective: Our research quantified associations between pre-migration exposure to the peace agreement in Guatemala and the post-migration health status of Guatemalan immigrants in the United States. Methods: We used chi-square tests to compare the distribution of health status before and after peace. We used ordered probit regressions to estimate associations between peace in Guatemala and health in the United States, conditional on the observed distributions of age, age squared, age cubed, and linear time trends before and after peace. Findings: The study sample included 4,115 female and 5,282 male Guatemalan immigrants between the ages of 15 and 85. The mean age was 38.8 years for females (standard deviation, 14.2) and 35.4 years for males (standard deviation, 12.6). Chi-square tests found statistically significant differences in the distribution of health status before and after the peace agreement, for females (P < .001) and males (P < .001). In unadjusted results, the peace agreement was associated with a 7.3 percentage point increase in excellent post-migration health for females (95% confidence interval, 4.9 to 9.8) and a 6.0 percentage point increase for males (95% confidence interval, 3.8 to 8.2). In adjusted results, we found that the peace agreement was associated with a 6.1 percentage point increase in excellent post-migration health for females (95% confidence interval, 0.8 to 11.4) and a 5.5-percentage point increase for males (95% confidence interval, 1.0 to 10.0). Conclusions: The peace agreement in Guatemala was associated with statistically significant improvements in the health status of Guatemalan immigrants to the United States

Armed Conflict in Central America and Immigrant Health in the United States

Background: While many researchers document the immediate and localized health effects of armed conflicts on combatants are well documented in the literature, less is known about the effects of armed conflict on individuals who have subsequently migrated elsewhere. Objective: This study aims to estimate associations between pre-migration armed conflict in Central America and post-migration health in the United States. Methods: We created a new dataset that combines information on armed conflicts in Central America and immigrant health in the United States. We used ordered probit regressions to estimate age-adjusted associations between pre-migration armed conflict and post-migration health. Findings: The study sample of Central American immigrants included 15,563 females and 16,236 males between the ages 15 and 69. The mean age was 37.2 years (standard deviation, 11.6 years) for females and 35.5 years (standard deviation, 11.2 years) for males. After adjusting for age, pre-migration armed conflict was associated with a 8.6 percentage point decrease in excellent health for females (95% confidence interval, 6.0 to 11.1), and a 7.3 percentage point decrease for males (95% confidence interval, 4.0 to 10.7). Each decade of pre-migration armed conflict was associated a 2.9-percentage point decrease in excellent health for females (95% confidence interval, 2.0 to 3.8) and a 1.6-percentage point decrease for males (95% confidence interval, 0.6 to 2.6). For those individuals exposed to armed conflict, each decade since the most recent armed conflict was associated with a 1.5 percentage point increase in excellent health for females (95% confidence interval, 0.4 to 2.5). For males, the average marginal effect of decades since last conflict was not statistically significant (95% confidence interval, –0.001 to 0.002). Conclusions: Pre-migration armed conflict in Central America is associated with decreases in excellent post-migration health in the United States. The effects of armed conflict are cumulative and fade over time for females

Subcellular localization of MC4R with ADCY3 at neuronal primary cilia underlies a common pathway for genetic predisposition to obesity.

Most monogenic cases of obesity in humans have been linked to mutations in genes encoding members of the leptin-melanocortin pathway. Specifically, mutations in MC4R, the melanocortin-4 receptor gene, account for 3-5% of all severe obesity cases in humans1-3. Recently, ADCY3 (adenylyl cyclase 3) gene mutations have been implicated in obesity4,5. ADCY3 localizes to the primary cilia of neurons 6 , organelles that function as hubs for select signaling pathways. Mutations that disrupt the functions of primary cilia cause ciliopathies, rare recessive pleiotropic diseases in which obesity is a cardinal manifestation 7 . We demonstrate that MC4R colocalizes with ADCY3 at the primary cilia of a subset of hypothalamic neurons, that obesity-associated MC4R mutations impair ciliary localization and that inhibition of adenylyl cyclase signaling at the primary cilia of these neurons increases body weight. These data suggest that impaired signaling from the primary cilia of MC4R neurons is a common pathway underlying&nbsp;genetic causes of obesity in humans

Nonclassic lipoid congenital adrenal hyperplasia masquerading as familial glucocorticoid deficiency

Context: Familial glucocorticoid deficiency (FGD) is an autosomal recessive disorder resulting from resistance to the action of ACTH on the adrenal cortex. Affected individuals are deficient in cortisol and, if untreated, are likely to succumb to hypoglycemia and/or overwhelming infection. Mutations of the ACTH receptor (MC2R) and the melanocortin 2 receptor accessory protein (MRAP), FGD types 1 and 2 respectively, account for approximately 45% of cases. Objective: A locus on chromosome 8 has previously been linked to the disease in three families, but no underlying gene defect has to date been identified. Design: The study design comprised single-nucleotide polymorphism genotyping and mutation detection. Setting: The study was conducted at secondary and tertiary referral centers. Patients: Eighty probands from families referred for investigation of the genetic cause of FGD participated in the study. Interventions: There were no interventions. Results: Analysis by single-nucleotide polymorphism array of the genotype of one individual with FGD previously linked to chromosome 8 revealed a large region of homozygosity encompassing the steroidogenic acute regulatory protein gene, STAR. We identified homozygous STAR mutations in this patient and his affected siblings. Screening of our total FGD patient cohort revealed homozygous STAR mutations in a further nine individuals from four other families. Conclusions: Mutations in STAR usually cause lipoid congenital adrenal hyperplasia, a disorder characterized by both gonadal and adrenal steroid deficiency. Our results demonstrate that certain mutations in STAR (R192C and the previously reported R188C) can present with a phenotype indistinguishable from that seen in FGD

Interleukin 1β and Prostaglandin E2 Affect Expression of DNA Methylating and Demethylating Enzymes in Human Gingival Fibroblasts

Periodontitis is a common chronic inflammatory condition that results in increased levels of inflammatory cytokines and inflammatory mediators. In addition to oral disease and tooth loss, it also causes low-grade systemic inflammation that contributes to development of systemic conditions including cardiovascular disease, pre-term birth, diabetes and cancer. Chronic inflammation is associated with epigenetic change, and it has been suggested that such changes can alter cell phenotypes in ways that contribute to both ongoing inflammation and development of associated pathologies. Here we show that exposure of human gingival fibroblasts to IL-1β increases expression of maintenance methyltransferase DNMT1 but decreases expression of de novo methyltransferase DNMT3a and the demethylating enzyme TET1, while exposure to PGE2 decreases expression of all three enzymes. IL-1β and PGE2 both affect global levels of DNA methylation and hydroxymethylation, as well as methylation of some specific CpG in inflammation-associated genes. The effects of IL-1β are independent of its ability to induce production of PGE2, and the effects of PGE2 on DNMT3a expression are mediated by the EP4 receptor. The finding that exposure of fibroblasts to IL-1β and PGE2 can result in altered expression of DNA methylating/demethylating enzymes and in changing patterns of DNA methylation suggests a mechanism through which inflammatory mediators might contribute to the increased risk of carcinogenesis associated with inflammation

Stretched Strings in Noncommutative Field Theory

Motivated by recent discussions of IR/UV mixing in noncommutative field theories, we perform a detailed analysis of the non-planar amplitudes of the bosonic open string in the presence of an external B-field at the one-loop level. We carefully isolate, at the string theory level, the contribution which is responsible for the IR/UV behavior in the field theory limit. We show that it is a pure open string effect by deriving it from the factorization of the one-loop amplitude into the disk amplitudes of intermediate open string insertions. We suggest that it is natural to understand IR/UV mixing as the creation of intermediate ``stretched strings''.Comment: 20 pages AMSLaTeX using JHEP.cls, 6 eps figures. Typos corrected and references adde

Mammut pacificus sp. nov., a newly recognized species of mastodon from the Pleistocene of western North America

A new species of mastodon from the Pleistocene of western North America, Mammut pacificus sp. nov. is herein recognized, with specimens identified throughout California and from two localities in southern Idaho. This new taxon differs from the contemporaneous M. americanum in having narrower teeth, most prominently in M3/m3, as well as six sacral vertebrae, femur with a proportionally greater mid-shaft diameter, and no mandibular tusks at any growth stage. All known Pleistocene Mammut remains from California are consistent with our diagnosis of M. pacificus, which indicates that M. americanum was not present in California

The incremental validity of borderline personality disorder relative to major depressive disorder for suicidal ideation and deliberate self-harm in adolescents

Few studies have examined the relation between suicide-related behaviors and Borderline Personality Disorder (BPD) in adolescent samples. The current study investigated the incremental validity of BPD relative to Major Depressive Disorder (MDD) for suicide-related behaviors in a psychiatric sample of adolescents at the cross-sectional level of analysis. The sample included N = 156 consecutive admissions (55.1% female; M age = 15.47; SD = 1.41), to the adolescent treatment program of an inpatient treatment facility. Of the sample 19.2% (n = 30) met criteria for BPD on the Child Interview for DSM-IV Borderline Personality Disorder and 39.1% (n = 61) met criteria for MDD on the Computerized Diagnostic Interview Schedule for Children-IV. Results showed that BPD conferred additional risk for suicidal ideation and deliberate self-harm. Our findings support the clinical impression that BPD should be evaluated in inpatient samples of adolescents either through intake interviews or more structured assessments