Tensile Properties and Microstructures of Laser-Formed Ti-6Al-4V

The room temperature tensile properties of Ti-6Al-4V alloy prepared under two different processing routes were evaluated and compared. One group of samples was prepared by conventional casting-forging-rolling into flat plates. The other group was prepared by using Triton\u27s Laser Free-Form Fabrication (LF3)(TM) processes, i.e., a laser was used to melt pre-alloyed powders of the required metallic composition as they were dropped onto a moveable substrate programmed to move in such a manner as to form a solid alloy plate. Five populations of Ti-6Al-4V were evaluated: a standard wrought form, an as-deposited form, a machined as-deposited form, a heat-treated as-deposited form, and a machined as-deposited and heat-treated form. The poorest mechanical properties occurred with the rough surfaces, likely due to existing microcracks and stress concentrations. The LF3 (TM) as-deposited material had mechanical properties comparable to, if not higher than, the mechanical properties of the wrought material. Further evaluations of the laser-formed material for complex spacecraft piece parts were warranted, specifically in regards to improving the surface finish of the materials

Engineered Single-Domain Antibodies with High Protease Resistance and Thermal Stability

The extreme pH and protease-rich environment of the upper gastrointestinal tract is a major obstacle facing orally-administered protein therapeutics, including antibodies. Through protein engineering, several Clostridium difficile toxin A-specific heavy chain antibody variable domains (VHHs) were expressed with an additional disulfide bond by introducing Ala/Gly54Cys and Ile78Cys mutations. Mutant antibodies were compared to their wild-type counterparts with respect to expression yield, non-aggregation status, affinity for toxin A, circular dichroism (CD) structural signatures, thermal stability, protease resistance, and toxin A-neutralizing capacity. The mutant VHHs were found to be well expressed, although with lower yields compared to wild-type counterparts, were non-aggregating monomers, retained low nM affinity for toxin A, albeit the majority showed somewhat reduced affinity compared to wild-type counterparts, and were capable of in vitro toxin A neutralization in cell-based assays. Far-UV and near-UV CD spectroscopy consistently showed shifts in peak intensity and selective peak minima for wild-type and mutant VHH pairs; however, the overall CD profile remained very similar. A significant increase in the thermal unfolding midpoint temperature was observed for all mutants at both neutral and acidic pH. Digestion of the VHHs with the major gastrointestinal proteases, at biologically relevant concentrations, revealed a significant increase in pepsin resistance for all mutants and an increase in chymotrypsin resistance for the majority of mutants. Mutant VHH trypsin resistance was similar to that of wild-type VHHs, although the trypsin resistance of one VHH mutant was significantly reduced. Therefore, the introduction of a second disulfide bond in the hydrophobic core not only increases VHH thermal stability at neutral pH, as previously shown, but also represents a generic strategy to increase VHH stability at low pH and impart protease resistance, with only minor perturbations in target binding affinities. These are all desirable characteristics for the design of protein-based oral therapeutics

More important than guns or grog: The role of television for the health and wellbeing of Australian Aboriginal prisoners

Published online: 30 Nov 2018This article examines the provision of television in the South Australian prison system and its importance to the identity, health, wellbeing and ontological security of Aboriginal prisoners. Existing research has explored the use of broadcast and print media by prisoners in the United Kingdom, United States and Europe and has established that television has an impact on incarcerated audiences far beyond its role as an ‘electronic babysitter’ or a means of filling time. It is also recognised that television plays a significant role in the lives of Aboriginal people (Michaels 1986). However, little is known about television in relation to incarcerated Aboriginal and Torres Strait Islander Australians. This article draws on data concerning in-cell television (‘TV’) among Aboriginal men in prison,1 which found that, when asked to identify the most important factors in the prison environment, 87 per cent of participants identified access to in-cell television as the single most important factor contributing to their congruency with prison accommodation. The article further indicates that access to in-cell television has the potential to reduce incidents of suicide and self-harm and should be adopted as a ‘best-practice’ principle for Aboriginal prisoners in Australian correctional environments.Elizabeth Grant and Yvonne Jewkeshttp://heinonline.org/HOL/Index?index=journals/cicj&collection=journal

Supporting Marine Corps Enhanced Company Operations : a quantitative analysis

This research explores the capability requirements for the employment of a Marine Rifle Company organized to conduct Enhanced Company Operations (ECO). It uses a simulation model, built in an agent-based simulation tool called MANA, to evaluate the logistical impact of ECO on a Marine Expeditionary Unit (MEU). ECO involves reorganizing and augmenting the traditional rifle company in a manner that contributes to "enhanced" command and control, intelligence, logistics, and fires capabilities. The end state is to develop the company's ability to become the base maneuver element of the Marine Air Ground Task Force, a role traditionally held by the infantry battalion. This research used a robust design of experiments method called the Nearly Orthogonal Latin Hypercube to vary a set of design factors in an efficient manner, culminating in over 5,460 simulated missions. Statistical results indicate that it is possible to support an enhanced company with current MEU assets, and that resupply responsiveness is more important than the unit's distance to the seabase. This research also confirms the validity of investing in the MV-22, due to the increased capabilities it brings to the MEU commander.http://archive.org/details/supportingmarine109455290US Marine Corps (USMC) authorApproved for public release; distribution is unlimited

4. TITLE AND SUBTITLE Supporting Marine Corps Enhanced Company Operations: A Quantitative Analysis

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After the congressional veto: Assessing the alternatives

Congressional choice of effective replacements for the recently banned legislative veto will require an accurate understanding of the actual results of the now unconstitutional device. The impact of the veto varied strikingly depending on, among other things, the type and target of the veto and on the principal sites of review in Congress itself. No single mechanism will suffice. Rather a variety of devices are available and under consideration. The underlying question raised by this analysis is which effects of the veto are worth perpetuating in light of past results and stated congressional objectives.

Calibration of the Beam-Position Monitor System for the SLAC PEP-II B Factory *

The Beam-Position Monitors (BPM) for the PEP-II B Factory consist of four 1.5cm diameter button style pickups mounted on the diagonals of the quadrupole vacuum chambers. Before installation of the vacuum chambers in the quadrupole assemblies, the electrical center of the BPMs is measured with respect to the mechanical center in a calibration test stand. In this paper the calibrations test stand is described and the precision and accuracy of the calibrations are presented. After installation of the quadrupole assemblies in the PEP-II tunnel, the passive attenuation for each channel of the system is measured to preserve the accuracy of the calibration. Finally, the active electronics includes an on-board calibrator. Results for these portions of the calibration are presented