140,326 research outputs found

    New paint and a new engine

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94505/1/23187_ftp.pd

    Scaling Film Cooling Adiabatic Effectiveness with Mass Transfer and Thermal Experimental Techniques

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    With increasing engine temperatures, it is becoming more important to design effective film cooling schemes. Low temperature, large scale tests are often implemented in the design process to reduce cost and complexity. A nondimensional adiabatic effectiveness can be used as an indication of the performance of a film cooling scheme. However, the coolant flow rate must be properly scaled between the low temperature tests and engine temperatures to accurately predict film cooling effectiveness. This process is complicated by gas property variation with temperature. Tests are commonly conducted using thermal measurement techniques with infrared thermography (IR), but the use of pressure sensitive paints (PSPs) can be used implementing the heat-mass transfer analogy. Thus, the question arises whether mass transfer methods can be used as a surrogate to thermal methods. In this study, a thermal technique with IR was compared to a heat-mass transfer method with PSP. A new method for collecting large datasets with PSP was implementing in this study to account for paint degradation. Results indicate that adiabatic effectiveness is best scaled by accounting for specific heat with the advective capacity ratio (ACR) using thermal techniques. Results also indicated that the mass flux ratio (M) is an appropriate parameter to scale adiabatic effectiveness results between gases using the mass transfer technique. This has significant implication for engine designers that rely on experimental data to predict engine behavior

    The New Zealand workforce survey II: occupational risk factors for asthma.

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    INTRODUCTION: We conducted a cross-sectional population-based survey in New Zealand that collected information on work history, current workplace exposures, and selected health outcomes. We report here the findings on occupational risk factors for asthma symptoms. METHODS: A random sample of men and women aged 20-64 years were selected from the New Zealand Electoral Roll and invited to take part in a telephone survey. Current asthma was defined as: (i) woken up by shortness of breath in the past 12 months; or (ii) an attack of asthma in the past 12 months; or (iii) currently taking asthma medication. Adult-onset asthma was defined as first attack of asthma at age 18 or over. Prevalence odds ratios (ORs) for all occupations were calculated using logistic regression adjusting for sex, age, smoking, and deprivation. RESULTS: Totally, 2903 participants were included in the analyses. The prevalence of current asthma was 17% and the prevalence of adult-onset asthma was 9%. Prevalence ORs for current asthma were elevated for ever working as a printer [OR = 2.26; 95% confidence interval (CI) = 1.09-4.66], baker (OR = 1.98; 95% CI = 1.02-3.85), sawmill labourer (OR = 3.26; 95% CI = 1.05-10.16), metal processing plant operator (OR = 2.48; 95% CI = 1.22-5.05), and cleaner (OR = 1.60; 95% CI = 1.09-2.35). Excess risks of adult-onset asthma were also found for ever working as a printer, baker, and sawmill labourer as well as ever-working as a market-oriented animal producer (OR = 1.66; 95% CI = 1.14-2.41), and other agricultural worker (OR = 2.08; 95% CI = 1.03-4.20). A number of occupations not previously considered at high risk for asthma were also identified, including teachers and certain sales professionals. CONCLUSION: This population-based study has confirmed findings of previous international studies showing elevated risks in a number of high-risk occupations. The strongest risks were consistently observed for printers, bakers, and sawmill labourers. Several occupations were also identified that have not been previously associated with asthma, suggesting that the risk of occupational asthma may be more widely spread across the workforce than previously assumed

    Flight service evaluation of Kevlar-49/epoxy composite panels in wide-bodied commercial transport aircraft

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    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after three years' service, and found to be performing satisfactorily. There are six Kevlar-49 panels on each aircraft, including sandwich and solid laminate wing-body panels, and 150 C service aft engine fairings. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure

    Clean Boating

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    Learn how to protect your boat, help control costs at the marina, and conserve the environment. This issue tells vessel owners the importance of communicating with marina management, responding properly to fuel spills, and using best management practices in waste disposal. Pointers are also included on how to avoid fire danger, prevent corrosion and electrolysis, follow safe procedures during fueling, and take necessary steps to winterize and store your vessel. This is volume 4 of the "Alaska Seas and Coasts" series.Ye

    Design of VR app applied to cognitive training

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    L’objectiu principal d’aquest projecte és el disseny d’una aplicació de realitat virtual per millorar el tractament dels pacients amb deteriorament cognitiu lleu, així com estudiar els possibles avantatges que aquesta tecnologia pot proporcionar en aquest camp. Es va escollir la realitat virtual perquè permet augmentar la sensació d’immersió pel que fa a les tecnologies actuals. Actualment la realitat virtual s’està utilitzant amb aquest tipus de tractament i està aconseguint gran resultats amb els pacients. A més, mitjançant l’ús d’aquesta tècnica d’immersió visual, s’espera que ajudi a millorar la capacitat dels pacients davant nous problemes, com pot ser la iniciació a la realitat virtual, una qüestió fonamental que ajuda a la millora dels pacients que es troben en les primeres etapes de la malaltia. L’aplicació consisteix en un entorn de supermercat virtual on el pacient pot realitzar diverses proves. En aquesta hi haurà diferents nivells amb diverses complexitats, sempre després d’haver realitzat un tutorial previ. L’aplicació s’ha realitzat en dues fases diferents: primer es va crear el guió, amb col·laboració amb la unitat d’Alzheimer de l’Hospital Clínic. Els nivells de l’aplicació es van definir aquí. El següent va ser la realització de l’aplicació amb col·laboració amb la companyia Vysion 360. Per a la seva utilització per la unitat d’Alzheimer de l’Hospital Clínic, l’aplicació tenia que complir diferents criteris. En primer lloc, els nivells de dificultat tenen que ser suficients per realitzar un tractament a llarg termini. En segon lloc, per crear una bona experiència de immersió, l’entorn creat té que ser el més realista possible. Finalment, s’ha creat una base de dades local per guardar la informació de totes les sessions, utilitzat posteriorment en l’anàlisi de evolució dels pacients. Amb aquesta aplicació, s’espera que els resultats en els pacients amb deteriorament cognitiu lleu milloren respecte a les tècniques anteriors. Especialment gràcies a la gran experiència d’immersió aconseguida amb la realitat virtual, la qual ajuda a la concentració dels pacients durant el tractament

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    Electrostatic propulsion beam divergence effects on spacecraft surfaces, volume 3

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    Tests were conducted to determine the effects of electrostatic propulsion beam divergence effects on spacecraft surfaces. The subjects discussed are: (1) sensitive surfaces on the ATS 6 spacecraft, (2) the cesium ion source and testing facility, (3) cesium ion effects on thermophysical properties, and (4) simulated charge-exchange ion exposure. The compatibility of the ATS 6 ion engine experiment with the engineering subsystems and other experiments aboard the ATS 6 spacecraft was analyzed
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