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A decrease in the c-lattice parameter was observed in Li1.2Co0.1Mn0.55Ni0.15O2 during constant voltage holding at 4.5 V by in situ X-ray diffraction. Comparison of magnetic susceptibility data before and after high-voltage hold reveals the change in average oxidation states of transition metal ions during high-voltage holding process. Transmission electron microscopy studies show the spinel reflections with fundamental trigonal spots from the particles after high-voltage hold indicating substantial structural modification. The structural transformation was believed to occur due to the oxygen release and/or the migration of transition metal cations to lithium layer during constant voltage holding.

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A comprehensive method for separating proton exchange membrane fuel cell (PEMFC) cathode catalyst-layer and gas diffusion layer (GDL) mass-transport overpotentials was derived utilizing kinetic and ohmic analysis of high humidified H 2 /O 2 and low humidified H 2 /air polarization data. A hybridized method was applied accounting for electrochemical surface area, hydrogen crossover, and exchange current density. This method delineates separate cathode GDL and electrode mass-transport overpotentials as a function of current density and operating time. The methodology is systematic and generalized and can be applied to polarization data from any type of durability test. The derivation was applied to periodic polarization data from a steady-state 1050 h durability test and is shown to provide an accurate breakdown of the sources of performance losses. Increases in mass-transport overpotential for the cathode GDL and oxygen reduction reaction overpotential were predominantly offset by improvements in the mass-transport overpotential of the cathode catalyst layer and reductions in the high frequency resistance. Little increase in the GDL mass-transport overpotential was observed during the first ∼500 h period, but a substantial increase was seen during the second ∼500 h period. The mass-transport overpotential of the cathode catalyst layer was almost negligible at the end of ∼1000 h of operation, suggesting little O 2 diffusion resistance through the ionomer and adjacent void volume.

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Neutron reflectivity (NR) is being used to measure simulated long-term behavior of idealized electrode interfacial structures in varying humidity environments. Nafion® ionomer dispersions were examined after deposition onto glassy carbon (GC) substrates before and after accelerated testing, and significant changes in the oxide content of GC and scattering length density of Nafion® were observed. Single layers of Nafion® and Nafion®/Pt bilayers on GC have also been investigated. Data was obtained for these samples with Nafion® 1100-EW films equilibrated in three different water vapor relative humidity (RH) environments - ambient ~10% H2O, 10% D2O, and 100% D2O. This data shows that a multilayer, in-situ NR model is needed to describe thin Nafion films when equilibrated with water vapor and is discussed in context of its implications on the oxygen reduction reaction and Pt-Nafion microelectrode studies.

Morphological changes occurring in membrane electrode assemblies (MEAs) were monitored using transmission electron microscopy (TEM) during the course of life testing of H 2 /air polymer electrolyte fuel cells (PEFCs). In the fresh catalyst layers, anode Pt particles were found to have smaller particle sizes, better dispersion, and less agglomeration on the carbon-support surfaces than did the cathode Pt 3 Cr alloy particles. The operation-induced agglomeration of catalyst particles was evaluated for both the anode and cathode after defined life testing periods. Agglomeration of catalyst particles occurred primarily during the first 500 h of testing, which was confirmed by both TEM analysis and electrocatalytic surface area measurement. After 500 h, degradation of the recast Nafion ionomer network within the catalyst layers likely contributes more significantly to MEA performance degradation. Migration of metal catalyst particles toward the interface between the catalyst layer and membrane was observed at both electrodes. The Pt anode catalyst was less stable than the Pt 3 Cr cathode catalyst under high current density and high humidity conditions, which was confirmed by the higher extent of migration observed for the pure Pt than for the Pt 3 Cr. Some Pt particles (from both electrodes) were found to migrate into the membrane during the testing period.

This work addresses issues of long-term durability of hydrogen-air polymer electrolyte fuel cells (PEFCs). The chromium in a Pt 3 Cr binary alloy catalyst has been found to migrate from cathode to anode during the course of life testing when operating within the oversaturated, or high-humidity, gas feed regime (one or both inlet feeds with a dew point equal to or higher than cell operating temperature) above 1 A/cm 2 current density. Other major factors such as membrane degradation, dissolution of catalyst-layer recast ionomer, catalyst oxidation, and catalyst agglomeration/growth have been identified as simultaneous, gradual processes that can lead to long-term PEFC failure. In situ cyclic voltammetry measurement of electrochemically active catalyst surface area shows a continuous decrease, revealing that catalyst agglomeration and/or growth may be a major cause of membrane electrode assembly degradation during middle-term life tests (i.e., operation times up to about 2000 h) under high-humidity conditions. Membrane and/or recast ionomer degradation was confirmed by the presence of fluoride and sulfate anions in the cathode outlet water. Scanning and transmission electron microscopy observation of a tested MEA suggest the loss of carbon-supported catalyst clusters and possible dissolution of recast Nafion ionomer.

MaleIps paraconfususselected a host, ponderosa pine (Pinus ponderosa), over a non-host, white fir (Abies concolor), only after the beetles had bored through the outer bark and into the phloem. Males, when given a choice between bark discs of these tree species in petri dishes, bored readily through the outer bark of either species. However, the beetles penetrated no more than 1 mm into the phloem of white fir, but they bored extensively in the phloem of ponderosa pine. The beetle’s preference for the pine over fir phloem was apparent with intact samples of phloem with the outer bark removed and with ground phloem. No preferences were apparent for the ground or intact pine or fir outer bark, with the phloem removed. The beetles bored preferentially in fissured as opposed to smooth outer bark of either tree. Beetles did not feed in the outer bark but did feed in the phloem of either species. In field experiments beetles attracted to logs of pine and fir bored through the outer bark of each species in nearly equal numbers. In white fir they re-emerged and departed soon after penetration of the phloem, whereas in ponderosa pine they continued excavation of tunnels in the phloem. In contrast, few beetles penetrated even the outer back of incense cedar (Calocedrus decurrens), another non-host species.

The possibility that the high blood cholesterol accompanying protected lipid feeding would cause deposition of cholesterol in body tissues and counteract advantages due to higher polyunsaturated fatty acid content was studied by comparing tissue cholesterol from cows, calves and steers fed polyunsaturated fats with those on conventional diets. Chuck, round, heart, liver, fat, plasma and milk were compared from cows fed either protected safflower oil-casein-formaldehyde (SOC-F), unprotected safflower oil-casein (SOC) or a conventional (control) hay-grain ration for 2–1/2 yr. Mean cholesterol, as mg %, for SOC-F, SOC and control cows were: chuck, 41, 52, 52; round, 46, 50, 50; heart, 96, 119, 103; liver 256, 231, 222; plasma, 336, 287, 200; milk, 12, 12, 12. Calves were fed milk high in 18:2 for 10 wk, followed by SOC-F for 8 wk, while a second group was fed normal milk, followed by SOC. Cholesterol for SOC-F and SOC calves were: chuck, 80, 68; plasma, 208, 166. Other calves were fed high 18:2 milk (SOC-F) or normal milk (control). Cholesterol for SOC-F and control were: chuck, 84, 68 (p < 0.025); round 72, 63; plasma, 197, 208. Ground beef of steers fed SOC-F or SOC for 6 wk had cholesterol levels of 67.1 and 65.0 mg/100 g and C18:2 levels of 14% and 2%. Our data show that the cholesterol content of these polyunsaturated meats was not greater than in conventional products.

Design parameters, tower configuration, and analysis and design considerations utilized in determining optimized 345-kv tangent tower to be used on southern half of Houston-Dallas Interconnecting 345-kv Transmission line; methods and means of analysis, design criteria, member selection, and proposed test of prototype tower are examined.

Improved techniques are described for cleaning gauges used in measuring the oleoresin exudation pressure (o.e.p.) of large numbers of ponderosa pines. These techniques are being used in a study of the relationship of o.e.p. and bark beetle attack in westside Sierra coniferous forests. Standard hydrostatic pressure gauges (Bourdon type) were modified by the addition of a threaded extension made of steel rod which permitted both insertion into a tree and newly-designed cleaning rack. A 9/32-in. hole in the steel rod reduced to a minimum the amount of oleoresin exudate necessary for an accurate reading. The cleaning racks, each accepting 30 gauges, were capped to confine the solvent (xylene) under pressure.

An in-depth historical and current review is presented on the science of lithium-ion battery (LIB) solid electrolyte interphase (SEI) formation on the graphite anode, including structure, morphology, composition, electrochemistry, and formation mechanism. During initial LIB operation, the SEI layer forms on the graphite surfaces, the most common anode material. The SEI is essential to the long-term performance of LIBs, and it also has an impact on its initial capacity loss, self-discharge characteristics, rate capability, and safety. While the presence of the anode SEI is vital, it is difficult to control its formation and growth, as they depend on several factors. These factors include the type of graphite, electrolyte composition, electrochemical conditions, and temperature. Thus, SEI formation and electrochemical stability over long-term operation should be a primary topic of future investigation in the LIB development. This article covers the progression of knowledge regarding the SEI, from its discovery in 1979 to the current state of understanding, and covers differences in the chemical and structural makeup when cell materials and components are varied. It also discusses the relationship of the SEI layer to the LIB formation step, involving both electrolyte wetting and subsequent slow charge–discharge cycles to grow the SEI.

General Motors requires that tires used on its vehicles meet certain performance requirements. Since the establishment of this Tire Performance Criteria (TPC) System, tire design, compounding technology, and testing capabilities have improved. Additional performance parameters important to the total tire/vehicle system have been identified and appropriate additional tire performance requirements have been established. Updated TPC test procedures and specifications are presented. Prior to 1984, three generations of TPC specification tires had been developed for General Motors' vehicles. For 1984 and 1985 model years, development of a fourth generation of TPC specification tires was completed. The considerations which led to establishment of performance goals are discussed. Test data in major tire performance categories are presented in general summary form comparing fourth generation to third generation TPC specification tires. Fourth generation tire performance specifications are contained in the Appendix.

Raw, commercial, and extrusion cooked full fat soy flours were treated with formaldehyde and then fed to dairy cows. This treatment protected the polyunsaturated fats of the soy from hydrogenation by microbial action in the cow’s rumen. With all of these materials, higher than usual amounts of polyunsaturated fats were incorporated into the milk. In a screening test limited to one cow, an advantage as measured by milk yield, fat yield, protein, solids-not-fat, and increased milk fat C18:2 was seen for the formaldehyde treated, full fat soy flour. The percentage of linoleic acid more than doubled in the milk fat of cows receiving the protected products. Only very slight quantities of formaldehyde (0.1–0.2 ppm) were found in the milk. The efficiency of transfer of the C18:2 from the feed to milk was ca. 37%. This represented a marked improvement over previous trials in which we fed expensive safflower oil-casein-formaldehyde supplements.

Describes the Data Reconfiguration Service (DRS) now being implemented at MIT, UCLA, UCSB and RAND for the ARPA computing network.

Inorganic solid-state electrolytes (SSEs), especially Li7La3Zr2O12 (LLZO), are promising candidates for all solid-state batteries. Generally, SSEs are synthesized by solid-state reactions at high temperatures. The high temperature required to synthesize useful polymorphs (e.g., cubic phase, in the case of LLZO) increases their production cost. To lower the synthesis temperature, several approaches, including doping and crystallite size control via sol-gel processes, have been explored. Recently, electrospinning was used to synthesize the inorganic SSE fibers to control the crystallite size and lower the calcination temperature. Several publications followed that investigated the properties of fibers and demonstrated the use of these fibers in inorganic-polymer composite SSEs. This paper presents a concise discussion of electrospinning, the parameters that control fiber morphology, the synthesis of inorganic SSE fibers, the effect of sintering conditions on the fiber morphology and composition, and the recent use of these fibers in making composite SSEs and other battery applications. Most of the discussion focuses on LLZO, but this paper also discusses applications of other types of electrospun inorganic electrolyte fibers, the challenges of using these fibers, and possible future directions in this research field.

The penta-aquamethylchromium(III) ion is formed in high yield from the chromium(II)–hydrogen peroxide–dimethyl sulphoxide system in aqueous solution. The methyl-deuteriated analogue has been prepared by the corresponding reaction with [2H6]dimethyl sulphoxide. The secondary kinetic deuterium isotope effect for the acid-catalysed aquation has been measured. The analogous ‘Fenton reagents’ with pentacyanocobaltate(II) and with vanadium(II) yield the pentacyanomethylcobaltate(III) ion and methane, respectively.

Fenton reagents (aqueous solutions of hydrogen peroxide and reducing metal ions) containing tracer tritium in the solvent are shown to effect a small amount of tritium exchange with a dissolved organic solute (dioxan or diethyl ether). The effectiveness of the metal ions (which are in stoicheiometric excess over hydrogen peroxide) follows the order CrII > VII > TiIII > FeII and is thought to reflect their reducing power towards the organic radicals (which are formed by hydrogen abstraction by hydroxyl radicals from the substrates). The reduction of radicals by CrII is known to proceed via the formation of isolable organochromium(III) complexes, and the trends in yields and rate constants suggest that the same sequence of steps may be involved with the other ions. The observation of exchange using the complex Cr(bipy)32+ in place of an ordinary metal ion of a Fenton reagent points to the additional possibility of outer-sphere reduction of radicals to carbanions as unstable intermediates. The low yield of the hydrogen isotope exchange in all cases is attributed to the combined operation of (i) a substantial kinetic isotope effect and (ii) reactions of radicals competing with their reduction.

The rates of some reactions of penta-aquaorganochromium(III) ions with electrophilic reagents (HgMe+, Br2, H3O+, and water) have been measured in mixtures of H2O and D2O. The first two reagents effect substitution on carbon without the formal involvement of water, and the observed solvent isotope effect is accordingly ascribed to the isotopic change in the five water ligands and, for the reaction with bromine, in the solvation of the incipient bromide ion. With this information an attempt has been made to separate the isotope effects on proton transfer from the isotope effects on the water ligands for aquation reactions involving aqueous hydrogen ion or water as a proton (deuteron) donor. It is shown that the large solvent and product isotope effects observed in these reactions are then readily explained in terms of fractionation factor theory. The analysis leads to transition-state fractionation factors in the range observed for the extensively studied reactions involving a rate-limiting proton transfer to carbon in purely organic substrates.