Cooling of rocket thrust chambers with liquid oxygen

Rocket engines using high pressure liquid oxygen (LOX) and kerosene (RP-1) as the propellants have been considered for future launch vehicle propulsion. Generally, in regeneratively cooled engines, the fuel is used to cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability at high temperatures and pressures. Therefore, LOX is being considered as an alternative coolant. However, there has been concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot-gas side wall. To address this concern, an investigation was previously conducted with simulated fatigue cracks upstream of the thrust chamber throat. When these chambers were tested, an unexpected melting in the throat region developed which was not in line with the simulated fatigue cracks. The current experimental program was conducted in order to determine the cause for the failure in the earlier thrust chambers and to further investigate the effects of cracks in the thrust chamber liner upstream of the throat. The thrust chambers were tested at oxygen-to-fuel mixture ratios from 1.5 to 2.86 at a nominal chamber pressure of 8.6 MPa. As a result of the test series, the reason for the failure occurring in the earlier work was determined to be injector anomalies. The LOX leaking through the simulated fatigue cracks did not affect the integrity of the chambers

High-pressure calorimeter chamber tests for liquid oxygen/kerosene (LOX/RP-1) rocket combustion

An experimental program was conducted to investigate the rocket combustion and heat transfer characteristics of liquid oxygen/kerosene (LOX/RP-1) mixtures at high chamber pressures. Two water-cooled calorimeter chambers of different combustion lengths were tested using 37- and 61-element oxidizer-fuel-oxidizer triplet injectors. The tests were conducted at nominal chamber pressures of 4.1, 8.3, and 13.8 MPa abs (600, 1200, and 2000 psia). Heat flux Q/A data were obtained for the entire calorimeter length for oxygen/fuel mixture ratios of 1.8 to 3.3. Test data at 4.1 MPa abs compared favorably with previous test data from another source. Using an injector with a fuel-rich outer zone reduced the throat heat flux by 47 percent with only a 4.5 percent reduction in the characteristic exhaust velocity efficiency C* sub eff. The throat heat transfer coefficient was reduced approximately 40 percent because of carbon deposits on the chamber wall

A new record of Percursaria percursa (Ulvaceae, Ulvales) on the North Island, New Zealand

The filamentous green alga Percursaria percursa (Ulvaceae, Ulvales) was recorded for the first time on the North Island of New Zealand at mokoroa Estuary, Tauranga Harbour. This species is previously known within New Zealand from only two records, both from the South Island. In Tauranga Harbour, this species was restricted to anoxic estuarine sediments where mangrove forests had been mulched, and mulchate left in situ. Percursaria percursa was found intertwined with Ulva spp. and Rhizoclonium spp. Surveys of other North and South Island estuaries suggest that this alga, although occurring as part of nuisance green algal blooms in Tauranga Harbour, has only colonized human-impacted locations, and has not yet been observed in natural' estuarine ecosystems in New Zealand. As this species was found intertwined with other mat-forming filamentous green algae, it can easily be misidentified in the field, leading to both over- and under-reporting of species occurrence

Understanding Lung Cancer Resources and Barriers among Worksites with Mostly Male Employees in Eight Rural Kentucky Counties: A Focus Group Discussion

Kentucky has the highest cancer incidence and mortality rates in the United States, and lung cancer is Kentucky\u27s leading cause of cancer deaths. Males in Kentucky have higher lung incidence and mortality rates than females. Through support from the SelfMade Health Network, Kentucky developed a Regional Resource Lead Organization that collaboratively developed a multi-component worksite intervention on lung cancer among male populations. The intervention targets eight Kentucky counties. The first component and focus of this manuscript included focus group meetings with organizational representatives in each county that provide health, educational, and social services to men and worksites. The focus groups discussed four distinct areas: (a) lung cancer-related resources and services in each county; (b) perceived ways men in worksites learn about and access health-related services; (c) identification of potential challenges and barriers to reaching men in worksites; and (d) creation of linkages and potential partnerships between community organizations and worksites. Forty-five organizational representatives participated in the eight focus groups. Most resources and services discussed were related to tobacco treatment. Employers were the most commonly perceived way men learn about and access health-related services, while attitudes and behaviors were the most commonly perceived barriers preventing men from accessing services. The most common potential linkages and partnerships across all areas were community organizations and groups, employers, health-care providers, and mass media. Partnering with employers may provide an opportunity to reach males with lung cancer prevention and control resources and services

Law Enforcement Preferences for PTSD Treatment and Crisis Management Alternatives

Evidence-based treatments (EBT) for posttraumatic stress disorder (PTSD) remain underutilized. Analog research, however, indicates that patients may be more amenable to receiving EBT for PTSD than utilization rates suggest. This study sought to extend previous studies by investigating PTSD treatment preferences among law enforcement individuals (i.e., active duty officers, cadets, criminal justice students). We asked 379 participants, with varying trauma histories, to read a police traumatic event and imagine they had developed PTSD. Participants rated the credibility of six treatment options which they might encounter in a treatment setting, and chose their most and least preferred treatments. Next, they evaluated a widely used debriefing intervention aimed at preventing PTSD. Almost 90% of participants chose exposure or cognitive processing therapy as their first or second most preferred treatment, and they rated these interventions as significantly more credible than the other 4 treatment options. The sample showed ambivalence regarding the perceived efficacy of debriefing but found the rationale credible. This study supports previous analog research indicating that patients may be more interested EBT than indicated by utilization rates, and suggests that law enforcement departments should consider offering EBT to officers who develop PTSD

Interprofessional Team Collaboration for Routine and Emergent Mental Health Concerns Among Collegiate Student-Athletes: A Case Series from the Association for Athletic Training Education Research Network

Collegiate student-athletes experience an increasing number of mental health concerns. To help address these concerns and provide high-quality health care for student-athletes, institutions of higher education are being encouraged to create interprofessional health care teams that are specifically dedicated to managing mental health. We interviewed 3 interprofessional health care teams who collaborate to manage routine and emergency mental health conditions in collegiate student-athletes. Teams represented all 3 National Collegiate Athletics Association (NCAA) divisions and included athletic trainers, clinical psychologists, psychiatrists, dietitians and nutritionists, social workers, nurses, and physician assistants (associates). The interprofessional teams indicated that the existing NCAA recommendations helped to solidify members and roles of the mental health care team; however, they all believed their teams would benefit from more counselors and psychiatrists. Teams had different mechanisms for referral and accessing mental health resources on their campuses, which may make on-the-job training for new members of the team an organizational necessity

Recruitment of latent pools of high-avidity CD8+ T cells to the antitumor immune response

A major barrier to successful antitumor vaccination is tolerance of high-avidity T cells specific to tumor antigens. In keeping with this notion, HER-2/neu (neu)-targeted vaccines, which raise strong CD8+ T cell responses to a dominant peptide (RNEU420-429) in WT FVB/N mice and protect them from a neu-expressing tumor challenge, fail to do so in MMTV-neu (neu-N) transgenic mice. However, treatment of neu-N mice with vaccine and cyclophosphamide-containing chemotherapy resulted in tumor protection in a proportion of mice. This effect was specifically abrogated by the transfer of neu-N–derived CD4+CD25+ T cells. RNEU420-429-specific CD8+ T cells were identified only in neu-N mice given vaccine and cyclophosphamide chemotherapy which rejected tumor challenge. Tetramer-binding studies demonstrated that cyclophosphamide pretreatment allowed the activation of high-avidity RNEU420-429-specific CD8+ T cells comparable to those generated from vaccinated FVB/N mice. Cyclophosphamide seemed to inhibit regulatory T (T reg) cells by selectively depleting the cycling population of CD4+CD25+ T cells in neu-N mice. These findings demonstrate that neu-N mice possess latent pools of high-avidity neu-specific CD8+ T cells that can be recruited to produce an effective antitumor response if T reg cells are blocked or removed by using approaches such as administration of cyclophosphamide before vaccination

Mesothelioma trends in the ACT and comparisons with the rest of Australia

OBJECTIVES Inhalation of asbestos fibres is the predominant cause of malignant mesothelioma. Domestic exposure to asbestos is a major community concern in the Australian Capital Territory (ACT) because of loose-fill asbestos home insulation. Little is known about how trends in mesothelioma rates in the ACT compare with those elsewhere. The objective of this study was to describe trends in mesothelioma rates in the ACT and compare them with those for the rest of Australia. METHODS We used de-identified data from the ACT Cancer Registry (1982- 2014), and the Western Australia (WA) Cancer Registry and the Australian Cancer Database (1982-2011). We calculated crude mesothelioma rates, by 3-year periods, for the ACT and for the rest of Australia (excluding WA). We used Poisson regression to analyse mesothelioma trends from 1994 to 2011 (complete reporting period) using an indirect standardisation approach to adjust for age and sex. RESULTS There were 140 mesothelioma cases reported to the ACT Cancer Registry between 1982 and 2014 - 81% male and 19% female. Between 1994 and 2011, age- and sex-adjusted mesothelioma rates in the ACT increased over time, on average by 12% per 3-year period (relative risk [RR] 1.12; 95% confidence interval [CI] 0.99, 1.26). Compared with the rest of Australia (excluding WA), ACT rates were, on average, lower (RR 0.84; 95% CI 0.69, 1.02), but they increased at a higher rate (RR 1.12 per 3-year period; 95% CI 0.99, 1.27). These results are strongly influenced by the higher rate of mesothelioma observed in the ACT in 2009-2011, when ACT rates became similar to those for the rest of Australia (excluding WA). CONCLUSIONS Although mesothelioma rates may have increased more in the ACT than the rest of Australia (excluding WA) during the past two decades, there is considerable uncertainty in the trends. More information is needed regarding the health risks associated with living in a house with loose-fill asbestos insulation. This is the subject of further studies within the ACT Asbestos Health Study.Includes Appendix table: Number of mesothelioma cases and person-years (PY) by sex, age group and year, ACT, 1982 to 201

Comparative susceptibility of mosquito populations in North Queensland, Australia to oral infection with dengue virus.

Dengue is the most prevalent arthropod-borne virus, with at least 40% of the world's population at risk of infection each year. In Australia, dengue is not endemic, but viremic travelers trigger outbreaks involving hundreds of cases. We compared the susceptibility of Aedes aegypti mosquitoes from two geographically isolated populations to two strains of dengue virus serotype 2. We found, interestingly, that mosquitoes from a city with no history of dengue were more susceptible to virus than mosquitoes from an outbreak-prone region, particularly with respect to one dengue strain. These findings suggest recent evolution of population-based differences in vector competence or different historical origins. Future genomic comparisons of these populations could reveal the genetic basis of vector competence and the relative role of selection and stochastic processes in shaping their differences. Lastly, we show the novel finding of a correlation between midgut dengue titer and titer in tissues colonized after dissemination

Receipt of Cardiac Medications Upon Discharge Among Men and Women With Acute Coronary Syndrome and Nonobstructive Coronary Artery Disease

Background Management of acute coronary syndrome (ACS) patients with nonobstructive epicardial coronary artery disease (CAD) remains poorly understood. Hypothesis Acute coronary syndrome patients with nonobstructive CAD are less likely to receive effective cardiac medications upon discharge from the hospital. Methods We identified patients hospitalized with ACS that underwent coronary angiography and had a 6-month follow-up. Patients were grouped by CAD severity: nonobstructive CAD (<50% blockage in all vessels) or obstructive CAD (≥50% blockage in ≥ 1 vessels). Data were collected on demographics, medications at discharge, and adverse outcomes at 6 months, for all patients. Results Of the 2264 ACS patients included in the study: 123 patients had nonobstructive CAD and 2141 had obstructive CAD. Cardiac risk factors including hypertension and diabetes were common among patients with nonobstructive CAD. Men and women with nonobstructive CAD were less likely to receive cardiac medications compared to patients with obstructive CAD including aspirin (87.8% vs 95.0%, P = 0.001), Β-blockers (74.0% vs 89.2%, P < 0.001), or statins (69.1% vs 81.2%, P = 0.001). No gender-related differences in discharge medications were observed for patients with nonobstructive CAD. However, women with nonobstructive CAD had similar rates of cardiac-related rehospitalization as men with obstructive CAD (23.3% and 25.9%, respectively). Conclusions Patients with nonobstructive CAD are less likely to receive evidence-based medications compared to patients with obstructive CAD, despite the presence of CAD risk factors and occurrence of an ACS event. Further research is warranted to determine if receipt of effective cardiac medications among patients with nonobstructive CAD would reduce cardiac-related events. Copyright © 2010 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64902/1/20701_ftp.pd