Benchmarking DoD Use of Additive Manufacturing and Quantifying Costs

Additive Manufacturing (AM), or three-dimensional (3D) printing as it is commonly referred to, is a rapidly developing technology that has the potential to revolutionize the way that firms develop and produce parts, as well as how they manage their supply chains. AM allows organizations to print prototypes, parts, tools, fixtures, tooling and a variety of other items at their production location. This can remove long lead times and high inventory levels for one-time or rare items. This research examines current AM use within the military services. Additionally, this study details the costs associated with fielding different levels of AM capability, specifically metal printing, production level polymer printing, and desktop level polymer printing. Finally, this research quantifies the cost of producing a metal part using AM. Ten parts with long lead times were chosen for analysis, and the cost calculated for AM production is compared to the price the Air Force currently pays to procure these parts. Topics for future research into of AM will be presented

2,2'-{2-[(E)-3-Phenylprop-2-enyl]-2,3-dihydro-1H-isoindol-1,3-diylidene}dimalononitrile, a π-deficient system for π...π (1:1) stacking investigations

The title compound, C₂₃H₁₃N₅, derived from cinnamyl alcohol and 2,2'-(isoindolin-1,3-diylidene)bispropanedinitrile, is a heterocyclic TCNQ analogue of interest as an electron-deficient component in charge-transfer complexes. A small perturbation of the four C-C≡N angles from linearity is observed, which are in the range 173.41 (18)-176.3 (2)°; the C≡N bond lengths are in the range 1.144 (2)-1.146 (2) Å. The terminal phenyl group is oriented at an angle of 77.17 (6)° to the C₄N ring and the C=C bond is short, 1.319 (2) Å. There are no classical hydrogen bonds, although intramolecular C-H...N and intermolecular C-H...π(arene) interactions influence the crystal-structure packing

Liquid Metal Application for Continuously Tunable Frequency Reconfigurable Antenna

This paper presents two different designs for frequency reconfigurable antennas capable of continuous tuning. The radiator, for both antenna designs, is a microstrip patch, formed from liquid metal, contained within a microfluidic channel structure. Both patch designs are aperture fed. The microfluidic channel structures are made from polydimethylsiloxane (PDMS). The microfluidic channel structure for the first design has a meander layout and incorporates rows of posts. The simulated antenna provides a frequency tuning range of approximately 118% (i.e. 4.36 GHz) over the frequency range from 1.51 GHz to 5.87 GHz. An experimental result for the fully filled case shows a resonance at 1.49 GHz (1.3% error compared with the simulation). Experienced rheological behavior of the liquid metal necessitates microfluidic channel modifications. For that reason, we modified the channel structure used to realise the radiating patch for the second design. Straight channels are implemented in the second microfluidic device. According to simulation the design yields a frequency tuning range of about 77% (i.e. 3.28 GHz) from 2.62 GHz to 5.90 GHz

Determination of parameters for successful spray coating of silicon microneedle arrays

Coated microneedle patches have demonstrated potential for effective, minimally invasive, drug and vaccine delivery. To facilitate cost-effective, industrial-scale production of coated microneedle patches, a continuous coating method which utilises conventional pharmaceutical processes is an attractive prospect. Here, the potential of spray-coating silicon microneedle patches using a conventional film-coating process was evaluated and the key process parameters which impact on coating coalescence and weight were identified by employing a fractional factorial design to coat flat silicon patches. Processing parameters analysed included concentration of coating material, liquid input rate, duration of spraying, atomisation air pressure, gun-to-surface distance and air cap setting. Two film-coating materials were investigated; hydroxypropylmethylcellulose (HPMC) and carboxymethylcellulose (CMC). HPMC readily formed a film-coat on silicon when suitable spray coating parameter settings were determined. CMC films required the inclusion of a surfactant (1%, w/w Tween 80) to facilitate coalescence of the sprayed droplets on the silicon surface. Spray coating parameters identified by experimental design, successfully coated 280 μm silicon microneedle arrays, producing an intact film-coat, which follows the contours of the microneedle array without occlusion of the microneedle shape. This study demonstrates a novel method of coating microneedle arrays with biocompatible polymers using a conventional film-coating process. It is the first study to indicate the thickness and roughness of coatings applied to microneedle arrays. The study also highlights the importance of identifying suitable processing parameters when film coating substrates of micron dimensions. The ability of a fractional factorial design to identify these critical parameters is also demonstrated. The polymer coatings applied in this study can potentially be drug loaded for intradermal drug and vaccine delivery

Valuing seasonal climate forecasts in the northern Australia beef industry

Seasonal climate forecasts (SCFs) provide opportunities for pastoralists to align production decisions to climatic conditions, as SCFs offer economic value by increasing certainty about future climatic states at decision-making time. Insufficient evidence about the economic value of SCFs was identified as a major factor limiting adoption of SCFs in Australia and abroad. This study examines the value of SCFs to beef production system management in northern Australia by adopting a theoretical probabilistic climate forecast system. Stocking rate decisions in October, before the onset of the wet season, were identified by industry as a key climate sensitive decision. The analysis considered SCF value across economic drivers (steer price in October) and environmental drivers (October pasture availability). A range in forecast value was found (0-$14/head) dependent on pasture availability, beef price and SCF skill. Skilful forecasts of future climate conditions offered little value with medium or high pasture availability, as in these circumstances, pastures were rarely over-utilised. In contrast, low pasture availability provided conditions for alternative optimal stocking rates and for SCFs to be valuable. Optimal stocking rates under low pasture availability varied the most with climate state (i.e. wet or dry), indicating that producers have more to gain from a skilful SCF at these times. Although the level of pasture availability in October was the major determinant of stocking rate decisions, beef price settings were also found to be important. This analysis provides insights into the potential value of SCFs to extensive beef enterprises and can be used by pastoralists to evaluate the cost-benefit of using a SCF in annual management

Liquid Metal Bandwidth-Reconfigurable Antenna

This letter shows how slugs of liquid metal can be used to connect/disconnect large areas of metalization and achieve a radiation performance not possible by using conventional switches. The proposed antenna can switch its operating bandwidth between ultrawideband and narrowband by connecting/disconnecting the ground plane for the feedline from that of the radiator. This could be achieved by using conventional semiconductor switches. However, such switches provide point-like contacts. Consequently, there are gaps in electrical contact between the switches. Surface currents, flowing around these gaps, lead to significant back radiation. In this letter, the slugs of a liquid metal are used to completely fill the gaps. This significantly reduces the back radiation, increases the bore-sight gain, and produces a pattern identical to that of a conventional microstrip patch antenna. Specifically, the realized gain and total efficiency are increased by 2 dBi and 24%, respectively. The antenna has potential applications in wireless systems employing cognitive radio (CR) and spectrum aggregation

Relationship between MRI Derived Right Ventricular Mass and Left Ventricular Involvement in Patients with Anderson-Fabry Disease

Poster presentationpublished_or_final_versio

Rabbit and Human Non-Keratinising Stratified Squamous Oesophageal Epithelium Displays Similar Microridge Structure by Scanning Electron Microscopy

Since the oesophageal epithelium of common laboratory animals, rats and mice, is keratinized it is unsuitable for comparison with typical non-keratinized stratified squamous human epithelium. It is thus important to find a suitable animal model for the study of human oesophageal tissue changes. This study investigated the microridge structure of immature and adult rabbit specimens, and adult human biopsies by scanning electron microscopy and morphometry. The investigation revealed a similarity between typical squamous human and adult rabbit oesophageal mucosal epithelium. While human epithelium specimens subdivided into two other groups (non-typical squamous and non-squamous); all typical squamous human biopsies were from patients who had normal endoscopy reports and no reflux symptoms. The surface cells of typical squamous human epithelium displayed complex microridge patterns (64% of cell surface) but patterns in non-typical squamous specimens were more variable (38%) (P \u3c 0.001) and cell boundaries less obvious. Rabbit squames displayed clear microridge patterns with an elevation in the percentage of cell surface covered by microridges, with increasing age, from immature to adult specimens (P \u3c 0.001). There was no statistically significant differences between adult rabbit, and \u27typical squamous\u27 human biopsies (range 51-65%), results which suggest potential use of a rabbit model to study changes in human oesophageal tissue

Multi-scale investigation of uranium attenuation by arsenic at an abandoned uranium mine, South Terras

Detailed mineralogical analysis of soils from the UK’s historical key uranium mine, South Terras, was performed to elucidate the mechanisms of uranium degradation and migration in the 86 years since abandonment. Soils were sampled from the surface (0 – 2 cm) and near-surface (25 cm) in two distinct areas of ore processing activities. Bulk soil analysis revealed the presence of high concentrations of uranium (<1690 ppm), arsenic (1830 ppm) and beryllium (~250 ppm), suggesting pedogenic weathering of the country rock and ore extraction processes to be the mechanisms of uranium ore degradation. Micro-focus XRF analysis indicated the association of uranium with arsenic, phosphate and copper; µ-XRD data confirmed the presence of the uranyl-arsenate minerals metazeunerite (Cu(UO2)2(AsO4)2·8H2O) and metatorbernite (Cu(UO2)2(PO4)2·8H2O) to be ubiquitous. Our data are consistent with the solid solution of these two uranyl-mica minerals, not previously observed at uranium-contaminated sites. Crystallites of uranyl-mica minerals were observed to coat particles of jarosite and muscovite, suggesting that the mobility of uranium from degraded ores is attenuated by co-precipitation with arsenic and phosphate, which was not previously considered at this site

Cardiovascular magnetic resonance demonstration of the spectrum of morphological phenotypes and patterns of myocardial scarring in Anderson-Fabry disease

published_or_final_versio