The measurement of lubricant-film thickness using ultrasound

Ultrasound is reflected from a liquid layer between two solid bodies. This reflection depends on the ultrasonic frequency, the acoustic properties of the liquid and solid, and the layer thickness. If the wavelength is much greater than the liquid-layer thickness, then the response is governed by the stiffness of the layer. If the wavelength and layer thickness are similar, then the interaction of ultrasound with the layer is controlled by its resonant behaviour. This stiffness governed response and resonant response can be used to determine the thickness of the liquid layer, if the other parameters are known. In this paper, ultrasound has been developed as a method to determine the thickness of lubricating films in bearing systems. An ultrasonic transducer is positioned on the outside of a bearing shell such that the wave is focused on the lubricant-film layer. The transducer is used to both emit and receive wide-band ultrasonic pulses. For a particular lubricant film, the reflected pulse is processed to give a reflection-coefficient spectrum. The lubricant-film thickness is then obtained from either the layer stiffness or the resonant frequency. The method has been validated using fluid wedges at ambient pressure between flat and curved surfaces. Experiments on the elastohydrodynamic film formed between a sliding ball and a flat surface were performed. Film-thickness values in the range 50-500 nm were recorded, which agreed well with theoretical film-formation predictions. Similar measurements have been made on the oil film between the balls and outer raceway of a deep-groove ball bearing

Thermal Imaging and Physiological Analysis of Cold-Climate Caribou-Skin Clothing

Protective clothing is essential for human existence in the Arctic, and caribou-skin clothing has played a pivotal role for millennia. Although people with northern experience often extol caribou-skin clothing, few scientific studies have investigated its properties. We used infrared thermal imaging in a pilot study to compare authentic caribou-skin clothing sewn by traditional Inuit seamstresses with two other types of cold-weather clothing: a standard-issue, Canadian army, winter uniform and an ensemble of modern retail clothing designed for extreme cold (a down anorak and snowmobile pants). To make the comparison, two subjects sequentially wore the three types of clothing—caribou skin, army uniform, and modern retail—in a still air, uniform thermal environment (where radiant temperatures of all environmental surfaces were equal to air temperature) at −21°C to −23°C (−6°F to −10°F). Thermal imaging quantifies the temperature of the outer surface of clothing, thereby providing key, functionally relevant information on the interface where clothing and environment meet. Under otherwise similar conditions, a low clothing surface temperature indicates superior clothing performance and a reduced rate of heat loss from the body to the environment. Caribou-skin clothing was similar to modern extreme-cold retail clothing: the whole-body composite surface temperature of our subjects wearing caribou-skin clothing was −22.1°C to −22.7°C, compared with −21.6°C in both subjects wearing the modern retail clothing. The army winter uniform (−18.9°C to −20.0°C) was inferior. These quantitative results were mirrored by the subjects’ subjective impressions. A particular advantage of thermal imaging is that it pinpoints locations in clothing where heat leaks occur. Although the two types of modern clothing exhibited heat leaks at zippered structures (even though fully closed), the caribou-skin clothing evaded such heat leaks by lacking such structures, because it is donned over the head. The integral hood characteristic of a caribou-skin parka was also superior in comparison to the detachable hood of the army uniform.Les vêtements de protection sont essentiels à l’existence humaine dans l’Arctique, et les vêtements en peau de caribou y jouent un rôle vital depuis des millénaires. Même si les gens qui ont évolué dans le Nord vantent souvent les mérites des vêtements en peau de caribou, peu d’études scientifiques ont été réalisées au sujet de leurs propriétés. Nous nous sommes servi d’imagerie thermique infrarouge dans le cadre d’une étude pilote visant à comparer les vêtements en peau de caribou authentique cousus par des couturières inuites traditionnelles à deux autres types de vêtements pour temps froid : un uniforme d’hiver standard de l’Armée canadienne et un ensemble de vêtements modernes du détail conçus pour des froids extrêmes (un anorak en duvet et des pantalons de motoneige). À des fins de comparaison, deux sujets ont porté, dans l’ordre séquentiel, les trois types de vêtements — vêtement en peau de caribou, uniforme de l’armée et vêtements modernes du détail — dans des conditions de vent nul thermique uniforme (où les températures radiatives de toutes les surfaces environnementales sont égales à la température de l’air) moyennant des températures allant de −21 °C à −23 °C (de −6 °F à −10 °F). L’imagerie thermique quantifie la température de la surface extérieure du vêtement, ce qui permet d’obtenir de l’information fonctionnellement pertinente et essentielle sur le point de rencontre du vêtement et de l’environnement. Dans des conditions par ailleurs semblables, la faible température du vêtement en surface indique un rendement supérieur pour ce vêtement et un taux réduit de perte de chaleur du corps à l’environnement. Les vêtements en peau de caribou ont donné des résultats semblables aux vêtements pour froid extrême modernes du détail : la température composite du corps entier de nos sujets portant les vêtements en peau de caribou variait de −22,1 °C à −22,7 °C, comparativement à −21,6 °C chez les deux sujets portant les vêtements modernes du détail. Les températures de l’uniforme d’hiver de l’armée étaient inférieures (de −18,9 °C à −20,0 °C). Ces résultats quantitatifs cadraient avec les impressions subjectives des sujets. Un des avantages particuliers de l’imagerie thermique, c’est qu’elle permet de repérer là où les pertes de chaleur se produisent dans les vêtements. Bien que les deux types de vêtements modernes perdaient de la chaleur à l’endroit des fermetures éclair (même si elles étaient fermées complètement), les vêtements en peau de caribou n’affichaient pas de telles pertes de chaleur en raison de l’absence de structures de ce genre parce que ces vêtements s’enfilent par la tête. Par ailleurs, il y a lieu de noter que la caractéristique intégrale du capuchon du parka en peau de caribou était également supérieure à celle du capuchon amovible de l’uniforme militaire

Heteromysis cocoensis n. sp. (Crustacea: Mysida: Mysidae) from coastal waters of Isla del Coco, Costa Rica

A survey of the invertebrate fauna of coral reef hard bottom communities in the shallow waters of Isla del Coco yielded a new species of mysid belonging to the genus Heteromysis S. I. Smith, 1873. Heteromysis (Olivemysis) cocoensis, n. sp. was collected from coral rubble at depths of 8 to 34 m. It differs from its congeners by having male pleopods 1, 3, and 4 with modified setae. Within the subgenus Olivemysis Băcescu, 1968, the new species is morphologically most similar to Heteromysis. ekamako Wittmann and Chevaldonne, 2017 from the Pacific, Heteromysis. gomezi Băcescu, 1970, H. mayana Brattegard, 1970, and H. rubrocinta, Băcescu, 1968 from the Western Atlantic, and Heteromysis. dardani Wittmann, 2008, Heteromysis. wirtzi Wittmann, 2008, and Heteromysis. sabelliphila Wittmann and Wirtz, 2017 from the Eastern Atlantic. However, H. cocoensis n. sp. is distinguished from these six apparently closely related species by the following combination of characters: flagellate, modified setae on articles 1 and 3 of the antennular peduncle, and setation of thoracic endopod 3, male pleopods 1, 3 and 4, uropodal endopods, and the apical and lateral margins of the telson. A diagnostic table separating these eight species is given.Universidad de Costa Rica/[]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

How low can SUSY go? Matching, monojets and compressed spectra

If supersymmetry (SUSY) has a compressed spectrum then the current mass limits from the LHC can be drastically reduced. We consider a possible 'worst case' scenario where the gluino and/or squarks are degenerate with the lightest SUSY particle (LSP). The most sensitive searches for these compressed spectra are via the final state LSPs recoiling against initial state radiation (ISR). Therefore it is vital that the ISR is understood and possible uncertainties in the predictions are evaluated. We use both MLM (with Pythia 6) and CKKW- L (with Pythia 8) matching and vary matching scales and parton shower properties to accurately determine the theoretical uncertainties in the kinematic distributions. All current LHC SUSY and monojet analyses are employed and we find the most constraining limits come from the CMS Razor and CMS monojet searches. For a scenario of squarks degenerate with the LSP and decoupled gluinos we find $M_{\tilde{q}}>340$ GeV. For gluinos degenerate with the LSP and decoupled squarks, $M_{\tilde{g}}>500$ GeV. For equal mass squarks and gluinos degenerate with the LSP, $M_{\tilde{q},\tilde{g}}>650$ GeV.Comment: References added, version submitted to ep

Positron interactions with water-total elastic, total inelastic, and elastic differential cross section measurements

9 págs.; 5 figs.; 4 tabs.© 2014 AIP Publishing LLC. Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.This work has been supported by the Australian Research Council’s Centre of Excellence Program. G.G. and F.B. would like to acknowledge the Spanish Ministerio de Economıa y Competitividad (project FIS2012-31230). Some financial support through COST Action “Nano-IBCT” is also gratefully acknowledged.Peer Reviewe

Advance care planning in patients with incurable cancer: Study protocol for a randomised controlled trial

Introduction: There is limited evidence documenting the effectiveness of Advance Care Planning (ACP) in cancer care. The present randomised trial is designed to evaluate whether the administration of formal ACP improves compliance with patients' end-of-life (EOL) wishes and patient and family satisfaction with care. Methods and analysis: A randomised control trial in eight oncology centres across New South Wales and Victoria, Australia, is designed to assess the efficacy of a formal ACP intervention for patients with cancer. Patients with incurable cancer and an expected survival of 3-12 months, plus a nominated family member or friend will be randomised to receive either standard care or standard care plus a formal ACP intervention. The project sample size is 210 patient-family/friend dyads. The primary outcome measure is family/friendreported: (1) discussion with the patient about their EOL wishes and (2) perception that the patient's EOL wishes were met. Secondary outcome measures include: documentation of and compliance with patient preferences for medical intervention at the EOL; the family/friend's perception of the quality of the patient's EOL care; the impact of death on surviving family; patient-family and patient-healthcare provider communication about EOL care; patient and family/ friend satisfaction with care; quality of life of patient and family/friend subsequent to trial entry, the patient's strength of preferences for quality of life and length of life; the costs of care subsequent to trial entry and place of death. Ethics and dissemination: Ethical approval was received from the Sydney Local Health District (RPA Zone) Human Research Ethical Committee, Australia (Protocol number X13-0064). Study results will be submitted for publication in peer-reviewed journals and presented at national and international conferences. Trial registration number: Pre-results; ACTRN12613001288718