A project and competition to design and build a simple heat exchanger

To address a declining interest in process engineering, a project to design and build a compact heat exchanger was initiated in the second year of a four-year, multidisciplinary degree programme in biotechnology. The heat exchangers had a double-pipe configuration and employed plastic outer pipes and copper inner pipes of various diameters. Designs produced ranged from coiled inner pipes to various multi-pass arrangements and were assessed on the basis of heat transfer achieved per unit mean temperature difference per unit cost. The project, which also formed the basis of a competition, was very well received by students and gave them hands-on experience of engineering design and construction, as well as team work, problem solving, engineering drawing and the use of simple tools. Based on the success of this project, a similar problem based learning approach will be initiated in the third year of the same degree programme and will focus on bioethanol production

Supply Chain Resilience: Assessing USAF Weapon System Life Cycle

The Air Force Global Logistics Support Center (AFGLSC) is responsible for the United States Air Force’s supply chain. One of the AFGLSC’s responsibilities is to improve AF supply chain processes. This thesis investigates the subject of supply chain resilience and its potential impact for improving supply chain management. Through literature a supply chain resilience framework and measurement tool was identified for potential benefit to Air Force supply chain management. Air Force weapon systems were identified and segmented into two phases of the weapon system life cycle. This research analyzes data collected on supply chain resilience factors, vulnerabilities and capabilities, for each individual weapon system to determine if differences exist as weapon systems progress through the weapon system life cycle. The results indicate that the supply chain resilience framework and measurement tool provides Air Force leadership with beneficial information to improve and assist in the strategic management of their supply chain

Comments on Guidance for Tax-Exempt Social Welfare Organizations on Candidate-Related Political Activities

The Notice is a good first step. It creates bright-line standards that are easy to apply and that will eliminate much of the gray area regarding permissible political activity. Clearer lines will reduce the discretion on the part of the IRS. By decreasing the IRS’s discretion, the regulation will reduce the opportunity for the IRS to be used as a political tool in an Administration’s tool box. However, the Notice does not go far enough. Congress has established a regulatory regime that has as its central purpose the disclosure of any significant campaign contributions by individuals or firms. In recent years many organizations have exploited the confidentiality rules of § 501(c)(4) to evade that regime, to the detriment not only of U.S. political discourse but also the non-profit sector. The Final Rule should ensure that groups with significant partisan political activity cannot obtain exemption under § 501(c)(4), or indeed under any parallel provision of § 501. We believe, however, that groups carrying out substantial electioneering activities should generally be eligible for exemption under § 527, and that the IRS should make that clear in the Final Rule. The main consequence of any ruling denying § 501(c)(4) status based on the political activity of the organization, therefore, would simply be to require the disclosure of an organization’s donors, and to ensure that the organization’s political expenditures are disclosed contemporaneously with the election they seek to influence. Accordingly, the Final Rule should be designed in a way that channels organizations with any substantial amount of undisclosed electioneering activity into § 527. For example, we propose a strong presumption that any group with candidate-related political activity of more than 10% of its budget, or of more than an overall cap of some amount, such as $1 million, whichever is lesser, should be recognized as a § 527 political organization and not as a § 501c(4) social welfare organization. The final rule should interpret electioneering broadly to include facially non-partisan activities that can be used to partisan advantage, including candidate-related advertising that falls outside the window immediately surrounding an election. Groups that voluntarily disclose their donors could retain c(4) status. Additionally, we suggest that the IRS seriously consider developing rules to limit the use of for-profit entities to evade § 527. We urge the IRS to take a clearer stand on its enforcement plans and legally dubious Forms 990. And we argue that nothing in the Notice, or in what we additionally suggest here, would raise serious First Amendment concerns

Localisation of gamma-ray interaction points in thick monolithic CeBr3 and LaBr3:Ce scintillators

Localisation of gamma-ray interaction points in monolithic scintillator crystals can simplify the design and improve the performance of a future Compton telescope for gamma-ray astronomy. In this paper we compare the position resolution of three monolithic scintillators: a 28x28x20 mm3 (length x breadth x thickness) LaBr3:Ce crystal, a 25x25x20 mm3 CeBr3 crystal and a 25x25x10 mm3 CeBr3 crystal. Each crystal was encapsulated and coupled to an array of 4x4 silicon photomultipliers through an optical window. The measurements were conducted using 81 keV and 356 keV gamma-rays from a collimated 133Ba source. The 3D position reconstruction of interaction points was performed using artificial neural networks trained with experimental data. Although the position resolution was significantly better for the thinner crystal, the 20 mm thick CeBr3 crystal showed an acceptable resolution of about 5.4 mm FWHM for the x and y coordinates, and 7.8 mm FWHM for the z-coordinate (crystal depth) at 356 keV. These values were obtained from the full position scans of the crystal sides. The position resolution of the LaBr3:Ce crystal was found to be considerably worse, presumably due to the highly diffusive optical in- terface between the crystal and the optical window of the enclosure. The energy resolution (FWHM) measured for 662 keV gamma-rays was 4.0% for LaBr3:Ce and 5.5% for CeBr3. The same crystals equipped with a PMT (Hamamatsu R6322-100) gave an energy resolution of 3.0% and 4.7%, respectively

Distinct phosphorylation clusters determines the signalling outcome of the free fatty acid receptor FFA4/GPR120

It is established that long-chain free fatty acids including ω-3 fatty acids mediate an array of biological responses through members of the free fatty acid receptor family, which includes FFA4. However, the signalling mechanisms and modes of regulation of this receptor class remain unclear. Here we employ mass spectrometry to determine that phosphorylation of mouse (m)FFAR4 occurs at five serine and threonine residues clustered in two separable regions of the C terminal tail, designated cluster 1 (Thr347, Thr349 and Ser350) and cluster 2 (Ser357 and Ser361). Mutation of these phospho-acceptor sites to alanine completely prevented phosphorylation of mFFA4 but did not limit receptor coupling to ERK1/2 activation. Rather an inhibitor of Gq/11 proteins completely prevented receptor signalling to ERK1/2. In contrast, the recruitment of arrestin 3, receptor internalization and activation of Akt were regulated by mFFA4 phosphorylation. The analysis of mFFA4 phosphorylation-dependent signalling was extended further by selective mutations of the phospho-acceptor sites. Mutations within cluster 2 did not affect agonist activation of Akt but instead significantly compromised receptor internalization and arrestin 3 recruitment. Distinctly, mutation of the phospho-acceptor sites within cluster 1 had no effect on receptor internalization and a less extensive effect on arrestin 3 recruitment, but significantly uncoupled the receptor from Akt activation. These unique observations define differential effects on signalling mediated by phosphorylation at distinct locations. This hallmark feature supports the possibility that the signalling outcome of mFFA4 activation can be determined by the pattern of phosphorylation (phosphorylation barcode) at the C-terminus of the receptor

Spaceflight Nutrition Research: Platforms and Analogs

Understanding human adaptation to weightlessness requires research in either the true microgravity environment or iii a ground-based model. Over the years, many flight platforms have been available, and many ground models have emerged for both human and animal studies of the effects of spaceflight on physiology. In this review, we provide a brief description of these models and the main points to be considered when choosing a model. We do not intend to provide a comprehensive overview of each platform or model, but rather to provide the reader with an overview of the options available for space nutrition research, and the relative merits and/or drawbacks of each

Photocontrol of Upper and Lower Rim Complexation of Neutral and Cationic Species by p-tert-butylcalix[4]arene Tetraethyl Ester

A number of sodium salt complexes of p-tert-butylcalix[4]arene tetraethyl ester, 1, were isolated both with and without upper-rim encapsulated solvent. Selective decomplexation of lower rim bound sodium cations and upper rim encapsulated solvent molecules could be successfully achieved using low pressure light sources. Oxidation of the counter anion at the lower rim of p-tert-butylcalix[4]arene tetraethyl ester triggered both the upper and lower rim decomplexation process. The extent of decomplexation at both rims is controlled both by the nature of the counter-anionic species at the lower rim and by the fate of the photoproducts generated. The calixarene host molecule, 1, remains intact during the decomplexation process

Time variability in the bipolar scattered light nebula of L1527 IRS: A possible warped inner disk

Context. The bipolar outflows associated with low-mass protostars create cavities in the infalling envelope. These cavities are illuminated by the central protostar and inner disk, creating a bipolar scattered light nebula at near-infrared and mid-infrared wavelengths. The variability of the scattered light nebula in both total intensity and intensity as a function of position in the scattered light nebula can provide important insights into the structure of the inner disk that cannot be spatially resolved. Aims. We aim to determine the likelihood that a warped inner disk is the origin of the surface brightness variability in the bipolar scattered light nebula associated with L1527 IRS. Methods. We present results from near-IR imaging conducted over the course of seven years, with periods of monthly cadence monitoring. We used Monte Carlo radiative transfer models to interpret the observations. Results. We find a time varying, asymmetrical brightness in the scattered light nebulae within the outflow cavities of the protostar. Starting in 2007, the surface brightnesses of the eastern and western outflow cavities were roughly symmetric. Then, in 2009, the surface brightnesses of the cavities were found to be asymmetric, with a substantial increase in surface brightness and a larger increase in the eastern outflow cavity. More regular monitoring was conducted from 2011 to 2014, revealing a rotating pattern of surface brightness variability in addition to a slow change of the eastern and western outflow cavities toward symmetry, but still not as symmetric as observed in 2007. We find that an inner disk warp is a feasible mechanism to produce the rotating pattern of surface brightness variability.Comment: 14 pages, 7 figures. Accepted for publication in Astronomy & Astrophysic

Altered TNF-Alpha, Glucose, Insulin and Amino Acids in Islets Langerhans Cultured in a Microgravity Model System

The present studies were designed to determine effects of a microgravity model system upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF-alpha) activity and indices of insulin and fuel homeostasis of pancreatic islets of Langerhans. Islets (1726+/-1 17,150 u IEU) from Wistar Furth rats were treated as: 1) HARV (High Aspect Ratio Vessel cell culture) , 2) HARV plus LPS, 3) static culture, 4) static culture plus LPS. TNF-alpha (L929 cytotoxicity assay) was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (p<0.05). A decrease in insulin concentration was demonstrated in the LPS stimulated HARV culture (p<0.05). We observed a greater glucose concentration and increased disappearance of arginine in islets cultured in HARVs. While nitrogenous compound analysis indicated a ubiquitous reliance upon glutamine in all experimental groups, arginine was converted to ornithine at a two-fold greater rate in the islets cultured in the HARV microgravity model system (p<0.05). These studies demonstrate alterations in LPS induced TNF-alpha production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV. These alterations in fuel homeostasis may be promulgated by gravity averaged cell culture methods or by three dimensional cell assembly