44,659 research outputs found
A device for generating motive force through the expansion of a non-elastic dense fluid
A device for generating motive force through the expansion of a dense, nonelastic fluid is described. It consists of an exterior block of a material with a low expansion coefficient, the interior of which is equipped with two circular cavities, both of which are equipped with rotors having blades constantly stressed outward by springs, so that they make contact with the cavity walls. One cavity is heated externally, and both have an exterior wall made of a friction ring which keeps the volume constant when their length varies. These cavities are interconnected by ducts which, at the inlet, are a prolongation of a peripheral groove made in the friction ring. The excess fluid produced by expansion flows through the groove, subsequently entering the cavity again after passing through a cooler located in the exterior part of the block. Both rotors are connected to gears with appropriate ratios which are equipped with a blocking device to guarantee that they always rotate in the same direction
Do price-tags influence consumers' willingness to pay ? On external validity of using auctions for measuring value
The paper considers the external validity of the growing set of literature that uses laboratory auctions to reveal consumers' willingness to pay for consumer goods, when the concerned goods are sold in retailing shops through posted prices procedures. Here, the quality of the parallel between the field and the lab crucially depends on whether being informed of the actual field price influences a consumer's willingness to pay for a good or not. We show that the elasticity of the WTP revision, according to the field price estimation error, is significant, positive and can be roughly approximate to one quarter of the error. We then discuss the normative implications of these results for future experiments aimed at eliciting private valuations through auctions.EXPERIMENTAL ECONOMICS;WILLINGNESS TO PAY;AUCTION;POSTED PRICE;VALUE ELICITATION;CONSUMER BEHAVIOR
Design Optimization for an Electro-Thermally Actuated Polymeric Microgripper
Thermal micro-actuators are a promising solution to the need for
large-displacement, gentle handling force, low-power MEMS actuators. Potential
applications of these devices are micro-relays, assembling and miniature
medical instrumentation. In this paper the development of thermal
microactuators based on SU-8 polymer is described. The paper presents the
development of a new microgripper which can realize a movement of the gripping
arms with possibility for positioning and manipulating of the gripped object.
Two models of polymeric microgripper electrothermo- mechanical actuated, using
low actuation voltages, designed for SU-8 polymer fabrication were presented.
The electro-thermal microgrippers were designed and optimized using finite
element simulations. Electro-thermo-mechanical simulations based on finite
element method were performed for each of the model in order to compare the
results. Preliminary experimental tests were carried out.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/handle/2042/16838
Detection of Carbon Monoxide within the Magellanic Bridge
The Mopra 22m and SEST 15m telescopes have been used to detect and partially
map a region of 12CO(1-0) line emission within the Magellanic Bridge, a region
lying between the Large and Small Magellanic Clouds. The emission appears to be
embedded in a cloud of neutral hydrogen, and is in the vicinity of an IRAS
source. The CO emission region is found to have a 60um/100um flux density ratio
typical for 12CO(1-0) detections within the SMC, although it has a
significantly lower 12CO brightness and velocity width. These suggest that the
observed region is of a low metallicity, supporting earlier findings that the
Magellanic Bridge is not as evolved as the SMC and Magellanic Stream, which are
themselves of a lower metallicity than the Galaxy. Our observations, along with
empirical models based on SMC observations, indicate that the radius of the
detected CO region has an upper limit of ~16 pc. This detection is, to our
knowledge, the first detection of CO emission from the Magellanic Bridge and is
the only direct evidence of star formation through molecular cloud collapse in
this region.Comment: 8 pages, 6 Figures. LaTeX. Accepted for publication by MNRA
Study, selection, and preparation of solid cationic conductors
Crystal chemical principles and transport theory have been used to predict structures and specific compounds which might find application as solid electrolytes in rechargeable high energy and high power density batteries operating at temperatures less than 200 C. Structures with 1-, 2-, and 3-dimensional channels were synthesized and screened by nuclear magnetic resonance, dielectric loss, and conductivity. There is significant conductivity at room temperature in some of the materials but none attain a level that is comparable to beta-alumina. Microwave and fast pulse methods were developed to measure conductivity in powders and in small crystals
Recommended from our members
Understanding needle-related distress in children with cystic fibrosis
Objective. To explore the nature and management of needle-related distress in children and adolescents with cystic fibrosis (CF).
Design. Qualitative study using semi-structured interviews.
Methods. Fourteen child–parent dyads took part. Children (5 male; 9 female) had a mean age of 12.4 years (range 7–17) and were mostly diagnosed with CF at birth (N= 11). Frequency of needle procedures ranged from once to six times a year. Parents (3 male; 11 female) had a mean age of 41.5 years and were from a variety of socio-economic backgrounds. Interviews were transcribed and analysed using thematic analysis.
Results. Most participants identified previous needle experiences and pain as related to their needle anxiety. Over half of parents and children considered ‘taking control’ to be the optimum coping strategy. The majority of parents and children thought inhaled nitrous oxide gas during needle procedures was helpful in managing needle-related distress. Parent and staff influences on needle-related distress are also examined.
Conclusions. Needle-related distress in children with CF has a substantial impact on children and their parents, and may lead to management problems and treatment refusal. Psychological and pharmacological interventions could reduce distress and aid management
Consistency of Lunar Orbiter residuals with trajectory and local gravity effects
Harmonic models and Doppler data used to analyze orbital perturbation of Lunar Orbite
- …