Directed Vapor Technologies (United States)

This work reports yarn pull-out studies of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride and silver) via a directed vapor deposition process. The uncoated control and metal-coated Kevlar® yarns are hand-woven into fabric swatches for quasi-static pull-out experiments. To perform these experiments, a yarn pull-out fixture is custom-designed and fabricated to apply transverse pre-tension to the fabric. Three levels of transverse pre-tensions are studied at 100 N, 200 N, and 400 N. The results showed that both peak pull-out force and energy absorption during the pull-out process increase with increase in transverse pre-tension. All the metal-coated groups showed an approximately 200% increase in peak pull-out force and a 20% reduction in tenacity compared to uncoated control. Furthermore, all the metal-coated groups showed an increase in energy absorption, with aluminum-coated yarns showing the highest increase of 230% compared to control. These results suggest enhanced frictional interactions during yarn pull-out in metal-coated yarns compared to uncoated control as evidenced by the surface roughness profile of individual fibers and inter-yarn frictional calculations.

Autorka v pojednání odpovídá na čtyři reflexe své knihy Hegelova fenomenologie světa. V první části se věnuje základním pojmům, tak jak je komentuje Pirmin Stekeler, který vyzdvihuje především vztah pojmu světa ke svému vlastnímu pojmu životních forem. Vypořádává se rovněž s odlišnými interpretacemi vztahu sebevědomí na straně jedné a boje na život a na smrt na straně druhé. V závěru tohoto oddílu se zaměřuje na Stekelerovu koncepci Fenomenologie ducha jako mundiceje. V této souvislosti se autorka obrací k tématu náboženství, které je stěžejní pro příspěvek Olgy Navrátilové. Autorka odmítá návrh Olgy Navrátilové chápat Hegelovu řeč o konci náboženství jako anticipaci zániku náboženství. Zdůrazňuje, že Hegel usiluje o podržení všech tří momentů ducha, které jsou na symbolické rovině vyjádřeny jako Otec – Syn – Duch Svatý. Přestože vychyluje dynamiku směrem k Duchu, netvrdí, že by pojem transcendence, tak jak jej na úrovni náboženství ztělesňuje Bůh, měl být překonán ve smyslu jeho zničení. V reakci na pojednání od Josefa Vojvodíka zdůrazňuje autorka důležitost děl romantiků pro Hegelovu filosofii, především ironie a humoru, avšak vždy v jejich objektivních, nikoliv subjektivních podobách. Ironie není vlastností subjektivního ducha, ale objektivní skutečnosti. V poslední části se autorka věnuje reflexi Tomáše Kordy, který vznáší nárok radikální aktualizace: podle autora by bylo záhodno domyslet Fenomenologii a promítnout její tezi, resp. Hegelovu filosofii vůbec do naší současnosti, a tak sledovat, do jaké míry se duch vzdělával i po Hegelově době. Tento typ aktualizace autorka odmítá a navrhuje, že aktualizovat je možné Hegelův styl, méně již jeho pojem dějin.

O que o filósofo canadense Charles Taylor chamou de ética da autenticidade foi o deslocamento do acento moral do geral para o particular. Assim sendo, fala-se de um significado moral independente e crucial para formar seres humanos verdadeiros e completos segundo a lógica do mundo atual. Este estudo compõe-se de uma pesquisa bibliográfica por meio da qual pretende demonstrar as consequências dessa nova forma de eticidade para o funcionamento dos regimes ditos democráticos, vez que, estes carecem bem mais do que o voto para um bom funcionamento das instituições públicas. Logo, se uma das características desse modelo ético é, exatamente, uma sociedade fragmentada, onde as inciativas dizem respeito apenas a interesses individuais ou corporativos, cresce – cada vez mais – o sentimento de que o eleitorado é indefeso contra o Estado que não é mais democrático, mas transvestido por um “despotismo suave”.

Abstract A novel research apparatus is developed to measure the fluid thermal conductivity while in shearing flow, and to determine its dependence on the shearing itself, contrary to the current state-of-the-art of measuring thermal conductivity under the condition of motionless fluid. A concentric cylinders’ apparatus was developed to provide controlled heat transfer in the radial direction, orthogonal to the circumferential fluid velocity, thus virtually preserving pure conductive heat transfer mode. The measurement and control are accomplished and integrated by using a computerized data acquisition system and a comprehensive virtual instrument, developed using the LabVIEW application software. It was found that the thermal conductivity of a Newtonian fluid, such as distilled water, was virtually independent of the fluid motion, as expected. However, for non-Newtonian fluids such as 1000 and 2000 wppm aqueous polyacrylamide (Praestol) solutions, there was up to 10–20% increase of thermal conductivity in the operating shear rate range (40 ≤ γ ≤ 510 sec−1) at 27°C average fluid temperature.

Fuel-cell electric vehicles have the potential to provide the range, acceleration, rapid refueling times, and other creature comforts associated with gasoline-powered vehicles, but with virtually no environmental degradation. To achieve this potential, society will have to develop the necessary infrastructure to supply hydrogen to the fuel-cell vehicles. Hydrogen could be stored directly on the vehicle, or it could be derived from methanol or other hydrocarbon fuels by on-board chemical reformation. This infrastructure analysis assumes high-pressure (5,000 psi) hydrogen on-board storage. This study evaluates one approach to providing hydrogen fuel: the electrolysis of water using off-peak electricity. Other contractors at Princeton University and Oak Ridge National Laboratory are investigating the feasibility of producing hydrogen by steam reforming natural gas, probably the least expensive hydrogen infrastructure alternative for large markets. Electrolytic hydrogen is a possible short-term transition strategy to provide relatively inexpensive hydrogen before there are enough fuel-cell vehicles to justify building large natural gas reforming facilities. In this study, the authors estimate the necessary price of off-peak electricity that would make electrolytic hydrogen costs competitive with gasoline on a per-mile basis, assuming that the electrolyzer systems are manufactured in relatively high volumes compared to current production. They then compare this off-peak electricity price goal with actual current utility residential prices across the US.

This report determines cost and performance requirements for Proton Exchange Membrane (PEM) fuel cell vehicles carrying pure H{sub 2} fuel, to achieve parity with internal combustion engine (ICE) vehicles. A conceptual design of a near term FCEV (fuel cell electric vehicle) is presented. Complete power system weight and cost breakdowns are presented for baseline design. Near term FCEV power system weight is 6% higher than ICE system, mid-term FCEV projected weights are 29% lower than ICE`s. There are no inherently high-cost components in FCE, and at automotive production volumes, near term FCEV cost viability is closer at hand than at first thought. PEM current vs voltage performance is presented for leading PEM manufacturers and researchers. 5 current and proposed onboard hydrogen storage techniques are critically compared: pressurized gas, cryogenic liquid, combined pressurized/cryogenic, rechargeable hydride, adsorption. Battery, capacitor, and motor/controller performance is summarized. Fuel cell power system component weight and cost densities (threshold and goal) are tabulated.

Alternative electrochemical power sources are under consideration for use In the Unmanned Underwater Vehicle (UUV) Prototype Program of the Defense Advanced Research Projects Agency. The current configuration uses a silver-zinc secondary battery to demonstrate the propulsion, structures, electronics, and mission systems of the UUV. An eight fold improvement in energy capacity can be realized, within the same volume, through various fuel cell and metal anode semi-cell options. A systems level analysis has been conducted to determine the overall energy capacity enhancement, vehicle performance, safety, cost/availability, and logistic considerations of these alternative electrochemical sources.