Long term storage test of titanium material with liquid fluorine propellant

The compatibility of 6AL-4V Ti with propellant grade GF2 and LF2 at 77 K for up to 3 years was investigated. Titanium double coupons, annealed or heat treated, with 16 or 64 RMS finishes, were immersed in F2 in individual Pyrex capsules and stored under LN2 for 29 and 39 months. Pre and post immersion tests were performed on the propellant and coupons. Chemical analysis of the propellant did not reveal any significant changes due to titanium corrosion. Gravimetric, visual, microscopic, and metallurgical examination with pitting analysis did not reveal gross corrosion of the titanium although pitting appears to be greater after 39 months exposure. The increase in pit size and number raises the possibility of unpredictable crack propagation instability. Fracture toughness tests are necessary to define this possibility

Water compatible resin for separation and recovery of dissolved precious metals

Trace Contaminants in Water: Genesis, Rapid Detection and Sustainable Removal Processes: abstract no. 353fOpen URL - http://apps.aiche.org/proceedings/Abstract.aspx?PaperID=119742The value of precious metals such as gold to be recovered in the industrial effluents within Pearl River Delta area is over HK$20 million per annual. Furthermore, with the expected tightening of environmental legislation and enforcement in the Mainland China, there is a growing need of effluent treatment technology. Traditionally, ion-exchange resin, polymer ultra-filtration and micro-emulsion are applied in the treatment of plating effluents. However, they all have different weaknesses. Many reports have been published for the separation using aqueous biphasic system. Based on this methodology, polystyrene-grafted-polyglycidol (PS-PG), a water-compatible polymer was synthesized. This type of polymer can be used for gold or silver extraction. After extraction, the recovery of metal can be achieved by direct electro-deposition or reverse extraction using sodium cyanide.postprintThe 2008 AIChE Annual Meeting (AIChE 100), Philadelphia, PA., 16-21 November 2008. In Conference Proceedings, 2008, p. 1-

An innovation approach on the separation of metal

There has been increasing environmental concerns on the metallic pollution in recent decades. The conventional technologies used for metal extraction are ion-exchange resins, polymer ultrafiltration and microemulsion. The whole extraction mechanism can be divided into 4 steps: 1) The binding of dissolved metal to active sites, 2) Separation of the metal load extractant from the lean phase, 3) Reverse extraction of loaded metal for recovery 4) Recycling of extractant for repeated extraction. Each of the conventional methods suffers different drawbacks in different steps of the extraction mechanism….postprintThe 2008 AIChE Annual Meeting (AIChE 100), Philadelphia, PA., 16-21 November 2008. In Proceedings of the 2008 AIChE Annual Meeting, AIChE 10

Produksi Antosianin Dari Daun Miana (Plectranthus Scutellarioides) Sebagai Pewarna Alami

Miana (Coleus scutellaroides) termasuk ke dalam tanaman hias yang berdaun tunggal dan berwarna ungu. Warna ungu yang terdapat pada daun miana adalah indikator keberadaan pigmen antosianin.Pemanfaatan daun miana sebagai sumber antosianin dapat dimanfaatkan sebagai pigmen alami untuk berbagai keperluan pewarna terutama dalam industri pangan, pemanenan antosianin pada daun miana dapat dilakukan setiap saat dan tidak bergantung pada musim dikarenakan ketersediannya yang selalu melimpah di alam.Tujuan dari penelitian ini adalah untuk mengisolasi, mengidentifikasi, dan mikroenkapsulasi pigmen antosianin dari daun miana.Berdasarkan hasil analisis didapati bahwa ekstrak pigmen daun miana memiliki karakteristik warna nampak ungu dan serapan maksimum absorbansinya berada pada panjang gelombang 529 nm, pigmen diduga sebagai turunan antosianin yaitu sianidin-3-rutinosida.Total antosianim yang sudah dimikroenkapsulasi sebesar 0.149542 mg/g. Dari hasil uji thermostabilitas pigmen terenkapsulasi maltodekstrin, stabilitas pigmen antosianin dari daun miana cenderung stabil dengan adanya pemaparan panas suhu 100C hingga 60 menit.Berdasarkan hasil dan pengujian, pigmen daun miana terenkapsulasi dapat menjadi pertimbangan produk untuk digunakan sebagai bahan tambahan pewarna dalam industri pangan

First direct observation of Dirac fermions in graphite

Originating from relativistic quantum field theory, Dirac fermions have been recently applied to study various peculiar phenomena in condensed matter physics, including the novel quantum Hall effect in graphene, magnetic field driven metal-insulator-like transition in graphite, superfluid in 3He, and the exotic pseudogap phase of high temperature superconductors. Although Dirac fermions are proposed to play a key role in these systems, so far direct experimental evidence of Dirac fermions has been limited. Here we report the first direct observation of massless Dirac fermions with linear dispersion near the Brillouin zone (BZ) corner H in graphite, coexisting with quasiparticles with parabolic dispersion near another BZ corner K. In addition, we report a large electron pocket which we attribute to defect-induced localized states. Thus, graphite presents a novel system where massless Dirac fermions, quasiparticles with finite effective mass, and defect states all contribute to the low energy electronic dynamics.Comment: Nature Physics, in pres

The Integrated Medical Model: Statistical Forecasting of Risks to Crew Health and Mission Success

The Integrated Medical Model (IMM) helps capture and use organizational knowledge across the space medicine, training, operations, engineering, and research domains. The IMM uses this domain knowledge in the context of a mission and crew profile to forecast crew health and mission success risks. The IMM is most helpful in comparing the risk of two or more mission profiles, not as a tool for predicting absolute risk. The process of building the IMM adheres to Probability Risk Assessment (PRA) techniques described in NASA Procedural Requirement (NPR) 8705.5, and uses current evidence-based information to establish a defensible position for making decisions that help ensure crew health and mission success. The IMM quantitatively describes the following input parameters: 1) medical conditions and likelihood, 2) mission duration, 3) vehicle environment, 4) crew attributes (e.g. age, sex), 5) crew activities (e.g. EVA's, Lunar excursions), 6) diagnosis and treatment protocols (e.g. medical equipment, consumables pharmaceuticals), and 7) Crew Medical Officer (CMO) training effectiveness. It is worth reiterating that the IMM uses the data sets above as inputs. Many other risk management efforts stop at determining only likelihood. The IMM is unique in that it models not only likelihood, but risk mitigations, as well as subsequent clinical outcomes based on those mitigations. Once the mathematical relationships among the above parameters are established, the IMM uses a Monte Carlo simulation technique (a random sampling of the inputs as described by their statistical distribution) to determine the probable outcomes. Because the IMM is a stochastic model (i.e. the input parameters are represented by various statistical distributions depending on the data type), when the mission is simulated 10-50,000 times with a given set of medical capabilities (risk mitigations), a prediction of the most probable outcomes can be generated. For each mission, the IMM tracks which conditions occurred and decrements the pharmaceuticals and supplies required to diagnose and treat these medical conditions. If supplies are depleted, then the medical condition goes untreated, and crew and mission risk increase. The IMM currently models approximately 30 medical conditions. By the end of FY2008, the IMM will be modeling over 100 medical conditions, approximately 60 of which have been recorded to have occurred during short and long space missions