4,330 research outputs found
Report on the ESO Workshop ''Science with ALMA Band 5''
No full textA small complement of receivers for the ALMA Band 5 (163-211 GHz) is under construction. This workshop was devoted to the scientific potential and goals of a full set of Band 5 receivers for ALMA, with emphasis on the detection of water in the local Universe and the 158 μm emission line of C+ from high redshift galaxies
Computational manikin for radiation simulation (male and female models covering 1-99% BMI and height diversity in US)
No full text3D meshes of adults in the United States covering 1 to 99 percentile variation in body mass index and height. Based on manikins generated from The National Health and Nutrition Examination Survey (NHANES) using the Manikin Fetcher tool from Open Design Lab. All manikins have simplified "mitten-finger" hands with effective radiation areas corresponding to the "average hand."
The manikin files are in the following format: "MB01P01"--referring to "M"-male "B01"-BMI percentile, "P01"-posture percentile. The percentile to absolute values are specified in the document "percentile to value" (PDF).
See the README for additional information.</p
CMS Production of iron plates in Russia/H Rykaczewski. Barrel situation/H Gerwig. Endcap situation/ D Loveless. Coil situation/D Campi. Review of physics group activities/D Denegri. NOVEL instrumental signatures of GMSB in CMS/G Wrochna
No full textNeed for monitoring and maintaining sustainable marine ecosystem services
No full textAbstract
Increases in human population and their resource use have drastically intensified pressures on marine ecosystem services. The oceans have partly managed to buffer these multiple pressures, but every single area of the oceans is now affected to some degree by human activities. Chemical properties, biogeochemical cycles and food-webs have been altered with consequences for all marine living organisms. Knowledge on these pressures and associated responses mainly originate from analyses of a few long-term monitoring time series as well as spatially scattered data from various sources. Although the interpretation of these data can be improved by models, there is still a fundamental lack of information and knowledge if scientists are to predict more accurately the effects of human activities. Scientists provide expert advices to society about marine system governance, but such advices should rest on a solid base of observations. Nevertheless, many monitoring programs around the world are currently facing financial reduction. Marine ecosystem services are already overexploited in some areas and sustainable use of these services can only be devised on a solid scientific basis, which requires more observations than presently available
Sustaining dry surfaces under water
No full textabstract: Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments.The final version of this article, as published in Scientific Reports, can be viewed online at: https://www.nature.com/articles/srep1231
Thermal and Vibration Characterization of Flexible Heat Sinks
No full textabstract: In nature, it is commonly observed that animals and birds perform movement-based thermoregulation activities to regulate their body temperatures. For example, flapping of elephant ears or plumage fluffing in birds. Taking inspiration from nature and to explore the possibilities of such heat transfer enhancements, augmentation of heat transfer rates induced by the vibration of solid and well as novel flexible pinned heatsinks were studied in this research project. Enhancement of natural convection has always been very important in improving the performance of the cooling mechanisms. In this research, flexible heatsinks were developed and they were characterized based on natural convection cooling with moderately vibrating conditions. The vibration of heated surfaces such as motor surfaces, condenser surfaces, robotic arms and exoskeletons led to the motivation of the development of heat sinks having flexible fins with an improved heat transfer capacity. The performance of an inflexible, solid copper pin fin heat sink was considered as the baseline, current industry standard for the thermal performance. It is expected to obtain maximum convective heat transfer at the resonance frequency of the flexible pin fins. Current experimental results with fixed input frequency and varying amplitudes indicate that the vibration provides a moderate improvement in convective heat transfer, however, the flexibility of fins had negligible effects.Dissertation/ThesisMasters Thesis Mechanical Engineering 201
Method for Generation of Pendant Drops Through Localized Condensation for Contact Angle Measurements in Conditions Deviating from Standard Environment
No full textabstract: Contact angle goniometer is one of the most common tools in surfaces science. Since the introduction of this instrument by Fox and Zisman1 in 1950, dispensing the liquid using a syringe has generated pendant drops. However, using such approach at conditions significantly deviating from standard pressure and temperature would require an elaborate and costly fluidic system. To this end, this thesis work introduces alternative design of a goniometer capable of contact angle measurement at wide pressure and temperature range. In this design, pendant droplets are not dispensed through a pipette but are generated through localized condensation on a tip of a preferentially cooled small metal wire encapsulated within a thick thermal insulator layer. This thesis work covers experimental study of the relation between the geometry of the condensation-based pendant drop generator geometry and subcooling, and growth rate of drops of representative high (water) and low (pentane) surface tension liquids. Several routes that the generated pendant drops can be used to measure static and dynamic contact angles of the two liquids on common substrates well as nanoengineered superhydrophobic and omniphobic surfaces are demonstrated.Dissertation/ThesisMasters Thesis Mechanical Engineering 201
A Friction and Adhesion Characterization Setup for Extreme Temperatures
No full textabstract: It is well known that the geckos can cling to almost any surface using highly dense micro/nano fibrils found on the feet that rely on Van Der Waals forces to adhere. A few experimental and theoretical approaches have been taken to understand the adhesion mechanism of gecko feet. This work explains the building procedure of custom experimental setup to test the adhesion force over a temperature range and extends its application in space environment, potentially unsafe working condition.
This study demonstrates that these adhesive capable of switching adhesive properties not only at room environment but also over a temperature range of -160 degC to 120 degC in vacuum conditions. These conditions are similar to the condition experienced by a satellite in a space orbiting around the earth. Also, this study demonstrated various detachment and specimen patch preparation methods. The custom-made experimental setup for adhesion test can measure adhesion force in temperature and pressure controlled environment over specimen size of 1 sq. inch. A cryogenic cooling system with liquid nitrogen is used to achieve -160 degC and an electric resistive heating system are used to achieve 120 degC in controlled volume. Thermal electrodes, infrared thermopile detectors are used to record temperature at sample and pressure indicator to record vacuum condition in controlled volume. Reversibility of the switching behaviour of the specimen in controlled environment confirms its application in space and very high or very low-temperature conditions.
The experimental setup was developed using SolidWorks as a design tool, Ansys as simulation tool and the data acquisition utilizes LabVIEW available in the market today.Dissertation/ThesisMasters Thesis Mechanical Engineering 201
- …
