Tribological Studies on Scuffing Due to the Influence of Carbon Dioxide Used as a Refrigerant in Compressors

The refrigeration and air conditioning industry has expressed a great interest in the use of carbon dioxide (CO2) as a refrigerant. CO2 is anticipated to replace HFC refrigerants, which are known to have a negative effect on the environment. The reason behind the interest in CO2 is the fact that it is a natural refrigerant, thus environmentally acceptable. Of course, such a replacement raises concerns regarding design criteria and performance due to the different thermodynamic properties of CO2 and the very different range of pressures required for the CO2 refrigeration cycle. So far, work related to CO2 has been done from a thermodynamics point of view and researchers have made significant progress developing automotive and portable air-conditioning systems that use the environmentally friendly carbon dioxide as a refrigerant. The purpose of this work is to develop an understanding of how CO2 plays a role from a tribology standpoint. More specifically, the goal of this work is to gain an understanding on how CO2 influences friction, lubrication, wear and scuffing of tribological pairs used in compressors. Work in the area of tribology related to CO2 is very limited. Preliminary work by Cusano and coworkers showed that consistent data for tests using CO2 could not be acquired nor could a satisfactory explanation be offered for the inconsistency. Their results triggered the initiation of the work presented here. In this first attempt to understand the tribological behavior of CO2 several problems were encountered. During this work we noted that its behavior, unlike conventional refrigerants, could not always be predicted. We believe that this can be attributed to the thermodynamic properties of CO2, which cannot be ignored when studying its tribological behavior. Thermodynamic Properties such as miscibility are very important when tribological testing is performed. A limiting factor with our tester was that it was not designed for CO2 testing, but for other conventional refrigerants and therefore made previously developed testing protocols non-applicable with CO2. Through a different approach and some modifications to our tester we were able to establish a protocol for testing under the presence of CO2. CO2 was then compared to R134a and the experimental results showed that it performs equally well.Air Conditioning and Refrigeration Project 13

Rancang Bangun Mesin Pemintal Agel

Industri kerajinan agel telah ada dan berkembang di beberapa wilayah di Indonesia. Sentra industri tali (tampar) agel berada di Desa Kapasan, Kecamatan Nguling, Kabupaten Pasuruan, sedangkan sentra industri kerajinan agel berada di Kecamatan Sentolo, Kabupaten Kulonprogo. Industri ini menghasilkan berbagai macam produk kerajinan bernilai ekonomi tinggi seperti; tas, topi, furnitur, noken dan masih banyak lagi produk kerajinan lainnya. Permasalahan yang dihadapi industri kerajinan agel adalah proses produksi dilakukan secara manual dengan keterbatasan pada kapasitas produksi dan ketidakstabilan kualitas produk bahan baku tali agel. Tujuan penelitian ini adalah untuk membuat prototype mesin pintal agel yang dapat mempersingkat tahapan proses dan meningkatkan kapasitas produksi industri kerajinan agel. Metode yang digunakan yaitu pengumpulan data melalui survey literatur dan lapangan, perancangan desain, penyiapan bahan dan alat, pembuatan mesin, uji coba dengan variabel kecepatan putaran dan panjang agel, analisa dan pembahasan hasil uji coba. Penelitian ini menghasilkan satu unit mesin pemintal agel dengan spesifikasi panjang: 110 cm, lebar: 46 cm, tinggi: 90 cm, kapasitas produksi : 47 m/jam, penggerak motor listrik 1 phase, 220 volt, 250 watt, 1400 rpm

Quantum Yield Calculations for Strongly Absorbing Chromophores

This article demonstrates that a commonly-made assumption in quantum yield calculations may produce errors of up to 25% in extreme cases and can be corrected by a simple modification to the analysis.Comment: 3 pages, 2 figures. Accepted by Journal of Fluorescenc

On Ex Situ NMR: Developing portable low-cost and/or single sided NMR/MRI

Nuclear magnetic resonance spectroscopy (NMR) is of unsurpassed versatility in its ability to non-destructively probe for chemical identity. Portable, low-cost NMR sensors would enable on site identification of potentially hazardous substances, such as signatures from production of nuclear, chemical, and biological weapon agents, narcotics, explosives, toxins, and poisons. There exist however problems that need to be considered in the case of such sensors: (a) small-scale magnets produce inhomogeneous magnetic fields and therefore undesired Larmor frequency distributions that conceal much of the useful spectral information, and (b) sensitivity in most experiments decreases due to the inherently low and strongly inhomogeneous fields associated with portable instruments. Our approach is to: (a) try to improve the field of low cost magnets either with hardware (e.g. magnet design and construction of ''shim coils'') or via special pulse sequences, where the field is ''effectively shimmed'' to appear homogeneous to the sample, and (b) to use microcoils to improve sensitivity and to allow focusing in smaller regions and therefore smaller static field variations. We have been working in setting up a table top, 2-Tesla permanent Halbach magnet system for tabletop NMR. The Spectrometer console is a Tecmag Apollo, controlled by a dell notebook. Currently an external linear chemagnetics rf amplifier is being used, though the power requirements for our system are quite low (a few Watts). The Magnetic Resonance lab in LLNL, has developed several types and sizes of microcoils, which have been proven to perform well for NMR experiments. We have evaluated an rf, 360 {micro}m O.D., microcoil probe that was built previously. We have finished mapping the magnetic field of the magnet. In the optimal position (in terms of field quality), the field inhomogeneity was at 17ppm. Preliminary fluorine spectra with a resolved two peak separation have now been obtained. For the field, as mapped, we have initial designs of first degree shimming, or gradient coils (linear correction to the field). We have calculated ''shim pulses'' to effectively shim the mapped field, for ideal gradient coils. These calculations will be repeated after the coils will be built and evaluated

Railton Community Assessment Project

A collaborative project between Railton Foundation and Stellenbosch University.This booklet is about sharing our process with other people so that they may be able to do the same in other communities. We have realised how valuable this kind of research is in the process of community development and we would like to help share our experiences of collaborative and community participative research. We hope that this handbook will serve as a guideline for any community leader, teacher or researcher who would like to undertake similar research projects. We realise that there are other ways of doing this, but you may find it helpful to see how we went about the community assessment process. In this booklet we will be providing background information that will help to create a context for doing this kind of research, and we will be outlining various steps in the process. To help bring life to this research process, we will give real lived experiences and examples from the Railton Community Assessment Project (CAP) team. Please consult the Railton Community Assessment Project Report for a comprehensive description of the research processes and findings referred to in this booklet. We hope this handbook is helpful to you and your community.Stellenbosch UniversityRailton FoundationPublishers' versio

A fruit diet rather than invertebrate diet maintains a robust innate immunity in an omnivorous tropical songbird

Experiments were funded by the Royal Netherlands Academy of Arts and Sciences (KNAW) Academy Ecology Fund to C.J.N—(KENMERK J1618/ECO/G437). C.J.N. was supported by a studentship funded by the Leventis Conservation Foundation through the University of St. Andrews UK and an Ubbo Emmius grant of the University of Groningen, The Netherlands. B.I.T. was supported by the Netherlands Organisation for Scientific Research (NWO‐Vidi 864.10.012).1. Diet alteration may lead to nutrient limitations even in the absence of food limitation, and this may affect physiological functions, including immunity. Nutrient limitations may also affect the maintenance of body mass and key life history events that may affect immune function. Yet, variation in immune function is largely attributed to energetic trade-offs rather than specific nutrient constraints. 2. To test the effect of diet on life history traits, we tested how diet composition affects innate immune function, body mass and moult separately and in combination with each other, and then used path analyses to generate hypotheses about the mechanistic connections between immunity and body mass under different diet composition. 3. We performed a balanced parallel and crossover design experiment with omnivorous common bulbuls Pycnonotus barbatus in out-door aviaries in Nigeria. We fed 40 wild-caught bulbuls ad libitum on fruits or invertebrates for 24 weeks, switching half of each group between treatments after 12 weeks. We assessed innate immune indices (haptoglobin, nitric oxide and ovotransferrin concentrations, and haemagglutination and haemolysis titres), body mass and primary moult, fortnightly. We simplified immune indices into three principal components (PCs), but we explored mechanistic connections between diet, body mass and each immune index separately. 4. Fruit fed bulbuls had higher body mass, earlier moult and showed higher values for two of the three immune PCs compared to invertebrate fed bulbuls. These effects were reversed when we switched bulbuls between treatments after 12 weeks. Exploring the correlations between immune function, body mass and moult, showed that an increase in immune function was associated with a decrease in body mass and delayed moult in invertebrate fed bulbuls, while fruit fed bulbuls maintained body mass despite variation in immune function. Path analyses indicated that diet composition was most likely to affect body mass and immune indices directly and independently from each other. Only haptoglobin concentration was indirectly linked to diet composition via body mass. 5. We demonstrated a causal effect of diet composition on innate immune function, body mass and moult: bulbuls were in better condition when fed on fruits than invertebrates, confirming that innate immunity is nutrient specific. Our results are unique because they show a reversible effect of diet composition on wild adult birds whose immune systems are presumably fully developed and adapted to wild conditions – demonstrating a short-term consequence of diet alteration on life history traits.Publisher PDFPeer reviewe

Can agricultural cultivation methods influence the healthfulness of crops for foods

The aim of the current study was to investigate if there are any health effects of long-term consumption of organically grown crops using a rat model. Crops were retrieved over two years from along-term field trial at three different locations in Denmark, using three different cultivation systems(OA, organic based on livestock manure; OB, organic based on green manure; and C, conventional with mineral fertilizers and pesticides)with two field replicates. The cultivation system had an impact on the nutritional quality, affecting γ-tocopherol, some amino acids, and fatty acid composition. Additionally, the nutritional quality was affected by harvest year and location. However, harvest year and location rather than cultivation system affected the measured health biomarkers. In conclusion, the differences in dietary treatments composed of ingredients from different cultivation systems did not lead to significant differences in the measured health biomarkers, except for a significant difference in plasma IgGl evels

Study protocol: can a school gardening intervention improve children's diets?

BACKGROUND: The current academic literature suggests there is a potential for using gardening as a tool to improve children's fruit and vegetable intake. This study is two parallel randomised controlled trials (RCT) devised to evaluate the school gardening programme of the Royal Horticultural Society (RHS) Campaign for School Gardening, to determine if it has an effect on children's fruit and vegetable intake. METHOD/DESIGN: Trial One will consist of 26 schools; these schools will be randomised into two groups, one to receive the intensive intervention as "Partner Schools" and the other to receive the less intensive intervention as "Associate Schools". Trial Two will consist of 32 schools; these schools will be randomised into either the less intensive intervention "Associate Schools" or a comparison group with delayed intervention. Baseline data collection will be collected using a 24-hour food diary (CADET) to collect data on dietary intake and a questionnaire exploring children's knowledge and attitudes towards fruit and vegetables. A process measures questionnaire will be used to assess each school's gardening activities. DISCUSSION: The results from these trials will provide information on the impact of the RHS Campaign for School Gardening on children's fruit and vegetable intake. The evaluation will provide valuable information for designing future research in primary school children's diets and school based interventions. TRIAL REGISTRATION: ISRCTN11396528

Анализ судебной практики по спорам, связанным с обжалованием корректировки ТС

В работе рассмотрена история развития нормативно-правовой базы таможенной стоимости с 1990-х по 2016 г. и процедуры корректировки ТС. Проанализирована судебная практика, связанная с обжалованием действий таможенных органов по корректировке таможенной стоимости за 2011-2016 гг. а также выявлены пути повышения эффективности процедуры корректировки ТС и обозначена рекомендуемая стратегия поведения для таможенных органов и участников ВЭД в вопросах корректировки таможенной стоимости.The work considers the history of the development of the regulatory framework of customs value from 1990 to 2016 and the procedures for updating the customs value. The judicial practice connected with the appeal of actions of customs bodies on adjustment of customs cost for 2011-2016 is analyzed. As well as ways to increase the effectiveness of the procedure for adjusting the customs value and outlined the recommended behavior strategy for the customs authorities and participants in foreign economic activity in matters of adjusting customs value