7,692 research outputs found
Performance of a building integrated photovoltaic/thermal (BIPVT) solar collector
The idea of combining photovoltaic and solar thermal collectors (PVT collectors) to provide electrical and heat energy is an area that has, until recently, received only limited attention. Although PVTs are not as prevalent as solar thermal systems, the integration of photovoltaic and solar thermal collectors into the walls or roofing structure of a building could provide greater opportunity for the use of renewable solar energy technologies. In this study, the design of a novel building integrated photovoltaic/thermal (BIPVT) solar collector was theoretically analysed through the use of a modified HottelâWhillier model and was validated with experimental data from testing on a prototype BIPVT collector.
The results showed that key design parameters such as the fin efficiency, the thermal conductivity between the PV cells and their supporting structure, and the lamination method had a significant influence on both the electrical and thermal efficiency of the BIPVT. Furthermore, it was shown that the BIPVT could be made of lower cost materials, such as pre-coated colour steel, without significant decreases in efficiency.
Finally, it was shown that by integrating the BIPVT into the building rather than onto the building could result in a lower cost system. This was illustrated by the finding that insulating the rear of the BIPVT may be unnecessary when it is integrated into a roof above an enclosed air filled attic, as this air space acts as a passive insulating barrier
Preliminary catalog of pictures taken on the lunar surface during the Apollo 16 mission
A catalog of all pictures taken from the lunar module or the lunar surface during the Apollo 16 lunar stay is presented. The tabulations are arranged for the following specific uses: (1) given the number of a particular frame, find its location in the sequence of lunar surface activity, the station from which it was taken and the subject matter of the picture; (2) given a particular location or activity within the sequence of lunar surface activity, find the pictures taken at that time and their subject matter; and (3) given a sample number from the voice transcript listed, find the designation assigned to the same sample by the lunar receiving laboratory
Application of Airborne Gamma Ray Spectrometric Surveys Meguma Terrane, Nova Scotia
Between 1976 and 1983 a series of airborne gamma-ray spectrometric surveys with flight lines spaced at one kilometer intervals were carried out in the Province of Nova Scotia. These surveys covered most of the Meguma Terrane and have yielded radioelement distribution patterns that have proven useful in delineating various aspects of the region's geology.
Within a cogenetic suite of Devonian-Carboniferous peraluminous granitic rocks uranium concentrations are shown to increase progressively with increasing differentiation while thorium concentrations reflect two contrasting trends- The most prevalent trend, shown by the granitic rocks of the eastern part of the South Mountain Batholith (New Ross area) and Eastern Meguma Terrane, is one of decreasing thorium concentrations with increasing differentiation. A second, less prominent trend exhibited by the granitic rocks of the western part of the South Mountain Batholith shows increasing thorium concentrations with increasing differentiation. The more prevalent inverse relationship between uranium and thorium results in high eU/eTh ratios associated with the more differentiated phases of the granitic suite. In addition, certain slate units of the Meguma Group are shown to have distinctly higher radioelement contents, in particular thorium, compared to the other slate units and the remainder of the Meguma Group.
Follow-up investigations of these airborne gamma-ray spectrometric surveys have confirmed the relationships between uranium and thorium. Limited lithogeochemical sampling has shown that those phases of the granitic suite which exhibit a high eU/eTh ratio also exhibit increased levels of other lithophlle elements, Sn and Be and occasionally Li and F.
RÉSUMÉ
Entre 1976 et 1983 une série de levées de terrains spectomètrlque aérien de rayons gamma, avec des lignes de vois éspacées à intervals d'un kilomètre, ont été effectuées dans la province de la Nouvelle Écosse. Ces levées s'étendent sur la pluspart du terrain Meguma et ont fourni aes pattrons de distribution d'éléments radioactifs qui ont été utiles pour décrire divers aspects de la géologie de la région.
Dans une suite Dévoniene-Carbonifère cogénétique de roches granitiques per-alumineuse, il a été démonté que les concentrations d' uranium augmentent progressivement avec des hausses de dlfférenciations alors que les concentrations de thorium montrent deux tendences contrastantes. La tendence la plus dominante, démontrée par les roches granitiques du batholithe de la "South Mountain", (région de New Ross) et du terrain "Eastern Meguma", est une baisse de concentration de thorium avec un accroissement de différenciation. Une autre tendance, moins accentuée, exposée par les roches granitiques de la partie de l'ouest du batholithe de la "South Mountain" montre une hausse des concentrations de thorium avec une hausse de différenciation. Les rélations inverses les plus dominantes entre l'uranium et le thorium donnent des rapports eU/eTh, qui sont associés avec les phases plus différenciees de la suite granitique. De plus, certaines unités d'ardoise du groupe Meguma, ont des teneurs d'éléments radioactlf qui sont nettement plus élevées, surtout pour le thorium, cooparé aux autres unités d'ardoise dans le reste du groupe Meguma.
De plus amples investigations de ces levées spectrometriques à rayons gamma, ont confirmé les rélations entre l'uranium et le thorium. Des prévèlements d'échantlllons limite de géochimie, ont demontré ces phases de la suite granitique, qui exposent de hautes proportions de eU/eTh, comprennent aussi des niveaux élevés d'autres éléments, lithophiles, Sn, Be, et desfois Li et F.
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The Higher Derivative Expansion of the Effective Action by the String-Inspired Method, Part I
The higher derivative expansion of the one-loop effective action for an
external scalar potential is calculated to order O(T**7), using the
string-inspired Bern-Kosower method in the first quantized path integral
formulation. Comparisons are made with standard heat kernel calculations and
with the corresponding Feynman diagrammatic calculation in order to show the
efficiency of the present method.Comment: 13 pages, Plain TEX, 1 figure may be obtained from the authors,
HD-THEP-93-4
Inpatient urine cultures are frequently performed without urinalysis or microscopy: Findings from a large academic medical center
OBJECTIVETo describe the frequency of urine cultures performed in inpatients without additional testing for pyuriaDESIGNRetrospective cohort studySETTINGA 1,250-bed academic tertiary referral centerPATIENTSHospitalized adultsMETHODSThis study included urine cultures drawn on 4 medical and 2 surgical wards from 2009 to 2013 and in the medical and surgical intensive care units (ICUs) from 2012 to 2013. Patient and laboratory data were abstracted from the hospitalâs medical informatics database. We identified catheter-associated urinary tract infections (CAUTIs) in the ICUs by routine infection prevention surveillance. Cultures without urinalysis or urine microscopy were defined as âisolated.â The primary outcome was the proportion of isolated urine cultures obtained. We used multivariable logistic regression to assess predictors of isolated cultures.RESULTSDuring the study period, 14,743 urine cultures were obtained (63.5 cultures per 1,000 patient days) during 11,820 patient admissions. Of these, 2,973 cultures (20.2%) were isolated cultures. Of the 61 CAUTIs identified, 31 (50.8%) were identified by an isolated culture. Predictors for having an isolated culture included male gender (adjusted odds ratio [aOR], 1.22; 95%; confidence interval [CI], 1.11â1.35], urinary catheterization (aOR, 2.15; 95% CI, 1.89â2.46), ICU admission (medical ICU aOR, 1.72; 95% CI, 1.47â2.00; surgical ICU aOR, 1.82; 95% CI, 1.51â2.19), and obtaining the urine culture â„1 calendar day after admission (1â7 days aOR, 1.91; 95% CI. 1.71â2.12; >7 days after admission aOR, 2.81; 95% CI, 2.37â3.34).CONCLUSIONSIsolated urine cultures are common in hospitalized patients, particularly in patients with urinary catheters and those in ICUs. Interventions targeting inpatient culturing practices may improve the diagnosis of urinary tract infections.Infect Control Hosp Epidemiol2017;38:455â460</jats:sec
Study of methane fuel for subsonic transport aircraft
The cost and performance were defined for commercial transport using liquid methane including its fuel system and the ground facility complex required for the processing and storage of methane. A cost and performance comparison was made with Jet A and hydrogen powered aircraft of the same payload and range capability. Extensive design work was done on cryogenic fuel tanks, insulation systems as well as the fuel system itself. Three candidate fuel tank locations were evaluated, i.e., fuselage tanks, wing tanks or external pylon tanks
Intra-individual movement variability during skill transitions: A useful marker?
Applied research suggests athletes and coaches need to be challenged in knowing when and how much a movement should be consciously attended to. This is exacerbated when the skill is in transition between two more stable states, such as when an already well learnt skill is being refined. Using existing theory and research, this paper highlights the potential application of movement variability as a tool to inform a coachâs decision-making process when implementing a systematic approach to technical refinement. Of particular interest is the structure of co-variability between mechanical degrees-of-freedom (e.g., joints) within the movement systemâs entirety when undergoing a skill transition. Exemplar data from golf are presented, demonstrating the link between movement variability and mental effort as an important feature of automaticity, and thus intervention design throughout the different stages of refinement. Movement variability was shown to reduce when mental effort directed towards an individual aspect of the skill was high (target variable). The opposite pattern was apparent for variables unrelated to the technical refinement. Therefore, two related indicators, movement variability and mental effort, are offered as a basis through which the evaluation of automaticity during technical refinements may be made
Small bowel stomas are associated with higher risk of circulating food-specific-IgG than patients with organic gastrointestinal conditions and colostomies
Objective The effects of food sensitivity can easily be masked by other digestive symptoms in ostomates and are unknown. We investigated food-specific- IgG presence in ostomates relative to participants affected by other digestive diseases.
Design Food-specific- IgG was evaluated for 198 participants with a panel of 109 foods. Immunocompetency status was also tested. Jejunostomates, ileostomates and colostomates were compared with individuals with digestive tract diseases with inflammatory components (periodontitis, eosinophilic esophagitis, duodenitis, ulcerative colitis, Crohnâs disease and appendicitis), as well as food malabsorption due to intolerance. A logistic regression model with covariates was used to estimate the effect of the experimental data and demographic characteristics on the likelihood of the immune response.
Results Jejunostomates and ileostomates had a significant risk of presenting circulating food-specific- IgG in contrast to colostomates (OR 12.70 (p=0.002), 6.19 (p=0.011) and 2.69 (p=0.22), respectively). Crohnâs disease, eosinophilic esophagitis and food malabsorption groups also showed significantly elevated risks (OR 4.67 (p=0.048), 8.16 (p=0.016) and 18.00 (p=0.003), respectively), but not the ulcerative colitis group (OR 2.05 (p=0.36)). Individuals with profoundly or significantly reduced, and mild to moderately reduced, levels of total IgG were protected from the formation of food-specific IgG (OR 0.09 (p=\u3c0.001) and 0.33 (p=0.005), respectively). Males were at higher risk than females.
Conclusion The strength of a subjectâs immunocompetence plays a role in the intensity to which the humoral system responds via food-specific- IgG. An element of biogeography emerges in which the maintenance of a colonic space might influence the risk of having circulating food-specific- IgG in ostomates.
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