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Since the development of the Nimonic1 alloys for Sir Frank Whittle’s first jet engine, Henry Wiggin Ltd, now part of Special Metals Corporation, has been involved with the design and improvement of nickel alloys for aerospace engineering. Whilst much of this work continues to be in relation to alloys for the high strength/high temperature applications of turbine blades, discs, seals, rings and casings of aero engines, nickel alloys are being utilised for other key aerospace engineering areas such as tooling for composite manufacture. The focus of this paper is on four recent developments in nickel alloys for aerospace engineering, namely: disc alloys; low expansion superalloys; Inconel alloy 718SPF – a nickel base superalloy capable of being superplastically formed; Nilo (low expansion alloys) for composite tooling.

Refinement of the crystallographic structure of (1:1) CdII3[(FeIII/CoIII)(CN)6]2·14H2O (I) has been carried out by means of three-dimensional single-crystal X-ray diffractometry. This novel disordered mixed anionic complex crystallizes in the cubic space groupFm 3 m(Z=11/3) witha0=10.638(1) A. Based on 166 unique reflections, the employed full-matrix least-squares method yielded a final reliability factor ofR=0.041 (Rw=0.047) and a goodness-of-fit value (Σ2) of 1.79. Indexed power diffraction data are reported and evaluated according to the quantitative figures-of-meritF21=114 (0.007, 25) andM20=154.9. A thermal gravimetric analysis revealed 14 water molecules per formula unit and the experimental density is 1.93(5) Mg m−3[calc., 1.87(1) Mg m−3]. The divalent Cd atoms are linked to the (1:1) mixed metal atoms by linear cyanide bridging. The disordered structure I is isomorphous with the hydrated cobalticyanides of Mn and Cd. A hydrogen-bonding network is set up within cavities of the crystal lattice created by the molecular disorder. Selective geometric parameters as well as conoscopic and IR spectral results are presented.

A chiral anthrylamine derivative was prepared and adsorbed on the surface of pre-packed porous graphitic carbon, and was evaluated as a chiral stationary phase in packed-column supercritical (and sub-critical) fluid chromatography. It successfully separated the enantiomers of two commercial anti-inflammatory agents and also a series of racemic tropic acid derivatives.

Chiral separations of related compounds within a series of potassium channel activator (KCA) analogues were compared by supercritical fluid chromatography (SFC) and high-performance liquid chromatography (HPLC) at several temperatures between 0° and 52°C. Mobile phases as close as possible in performance were selected for the two modes of analysis, and the same chiral stationary phase (CSP) was used, namely, cellulose tris(3,5-dimethylphenyl-carbamate) (Chiralcel-OD). Two of the compounds, which differed only by replacement of a benzoyl group by a n-pentanoyl group, showed quite strikingly different temperature dependencies. These indicate that one compound is above, and the other below, its isoenantioselective temperature (Tiso), at which separation of enantiomers is not possible. The thermodynamic parameters for these chiral discriminations support the conclusion that, in spite of their very similar structures, quite different chiral recognition factors operate for these two racemic mixtures.

Using classical trajectory calculations the translational energy ratio of the final and initial energy ( E f E i ) for Ar inelastically scattered from a Pt(111) surface has been investigated for thermal and hyperthermal energies up to 30 eV. The Ar Pt (111) potential is based on a Hartree-Fock-Slater calculation for an Ar atom with a Pt4-cluster. The energy ratio varies strongly across the surface unit cell. There is a most unusual energy dependence: for energies below 16 eV the atop site shows the larger loss than the bridge and centre sites, whereas for higher energies the situation is reversed. This reversal can be understood in terms of a simple analytical model. The calculations show a site dependent onset for trapping and implantation.

A molecular dynamics simulation has been developed to study the trapping and scattering of rare gases at metal surfaces. We have carried out deterministic trajectory calculations of the interaction of Ar with a Pt(111) surface. We do not use the generalized Langevin method with periodic boundaries but instead use a crystal containing a relatively large number of atoms. The sandbag method is used to thermostat the surface. The interaction can be divided into two distinct channels; a trapping channel and a direct scattering channel. Trapping probabilities were calculated for different incident energies and angles for a range of surface temperatures (0 to 190 K). For low surface temperatures, the trapping scales with the normal kinetic energy of the Ar. The reported change in this energy scaling with surface temperature is shown to be due to atoms which trap but leave the surface after a short residence time. For the trapping channel, energy exchange with the surface was found to have greater efficiency for the perpendicular direction. Scattering has also been studied and the results are compared for high and low surface temperatures (80 and 500 K). The key issue addressed here is how the initial energy partitioning is changed as a consequence of interacting with the moving surface.

A molecular dynamics simulation using a large number of atoms has been developed to study scattering and trapping of heavy rare gases on metal surfaces. Trapping probabilities were calculated for different incident energies and angles for a range of surfaces temperatures for the Ar/Pt(111) system. At T s = 0 and 80 K trapping is strongly dependent upon the incident normal energy component and we observe near-normal energy scaling. At higher surface temperatures indirect inelastic scattering is observed. This fraction of the trajectories “desorbs” after a few bounces on the surface. During their encounters with the surface, these atoms begin to loose memory and as a consequence they overturn the normal energy scaling relationship.

The passivation behavior of nickel in 0.15 N Na2SO4 chloride-free solution is compared with that which occurs in a chloride-containing electrolyte. Insitu techniques, such as differential reflectometry and electrochemical polarization, are utilized in this study. The presence of Cl- ions did not alter the composition of the passivating film nor does Cl- alter the mechanisms by which passive film formation occurs. However, Cl− ions delay the growth of a passivating film at pH values of 4 and 8. In these solutions, film breakdown as well as severe pitting occurs subsequent to passivation. In contrast, in solutions of pH 12, the chlorides affect neither the film formation process nor film stability.

The purpose of this Safety Evaluation for Packaging (SEP) is to authorize the use of three U.S. Department of Transportation (DOT) 7A, Type A metal boxes (Capital Industries Part No. S 0600-0600-1080- 0104) to package 12 Plutonium Recycle Test Reactor (PRTR) ion exchange columns as low-level waste (LLW). The packages will be transferred from the 309 Building in the 300 Area to low level waste burial in the 200 West Area. Revision 1 of WHC-SD-TP-SEP-035 (per ECN No. 621467) documents that the boxes containing ion exchange columns and grout will maintain the payload under normal conditions of transport if transferred without the box lids

The Type B Drum package is a transportation cask capable of shipping a single 55-gal (208 L) drum of transuranic (TRU) waste. The Type B Drum is smaller than existing certified packages, such as the TRUPACT-II cask, but will allow payloads with higher thermal and gas generation rates, thus providing greater operational flexibility. The Type B Drum package has double containment so that plutonium contents and other radioactive material may be transported in Type B quantities. Conceptual designs of unshielded and shielded versions of the Type B Drum were completed in Report on the Conceptual Design of the Unshielded Type B Drum Packaging and Report on the Conceptual Design of the Shielded type B Drum Packaging (WEC 1994a, WEC 1994b), which demonstrated the Type B Drum to be a viable packaging system. A Type B package containment system must withstand the normal conditions of transport and the hypothetical accident conditions, which include a 9-m (30-ft) drop onto an unyielding surface and a 1-m (3-ft) drop onto a 15-cm (6-in.) diameter pin, and a fire and immersion scenarios.

HIV-I was used to spike a monoclonal antibody preparation which was subsequently purified by affinity chromatography. Presence of HIV-I was assessed at different stages of the process, by a syncitial assay, a p24 antigen ELISA, and by presence of reverse transcriptase. Keywords:- HIV-I, validation, syncitial assay, p24 core antigen, reverse transcriptase.

Simulation par dynamique moleculaire impliquant un grand nombre d'atomes pour suivre la dynamique d'un atome de gaz pendant les premieres etapes de piegeage

In situ differential reflectometry in conjunction with ESCA techniques are used to identify various surface films which form electrochemically on nickel. The film observed on pure Ni in a 0.15 N Na 2 SO 4 electrolyte has been identified to be primarily Ni(OH) 2 . At different values of pH and potential, NiO has been found to form simultaneously with Ni(OH) 2 . At solutions with pH > 8, the Ni(OH) 2 film partially transforms into a third oxide, presumably NiOOH, which can only be observed in situ .

Discussion sur le calcul du temps mort qui mene a des contradictions; on presente deux interpretations

A brief review is given of the physiological effects of carbon dioxide, methane, ammonia, and hydrogen sulphide on pigs. All of these components are evolved during the storage of manure in an under-slat pit. In addition, carbon dioxide is contributed by pig respiration. Manure composition is discussed in terms of broad chemical classes such as carbohydrates, proteins, and lipids. A tentative composition in terms of molar amounts of carbon, hydrogen, oxygen, nitrogen, and sulphur is then derived and used to predict the relative amounts of carbon dioxide, methane, ammonia, and hydrogen sulphide that would be generated during gasification of volatile solids. A simple model based on complete-mix anaerobic digesters is proposed for the kinetics of manure degradation in a pit. A mathematical model is then presented that predicts mass transfer between the manure and the air if bulk mean values of concentrations and partial pressures are known. The paper concludes with a presentation of numerical results from solution of the mathematical model for climatic and management conditions that are typical in the midwestern states of North America. The model indicates that carbon dioxide from pig respiration will be the component of greatest concern in a pig unit with good internal air movement. The model also suggests that hydrogen sulphide should not accumulate in the manure when there is adequate air movement over the manure. Mass balances on the four components suggest that the model is inadequate with respect to ammonia and that an additional phenomenon, such as urine on the slats, must be invoked to explain measured levels of ammonia in confinement-building atmospheres.

The film responsible for the passive behavior of nickel and the mechanisms of film formation was studied in situ. Electrochemical polarization techniques were used in conjunction with Differential Reflectometry. It was found that the film which causes nickel to passivate in 0.15 N Na2SO4 (pH = 4.0–12.0) is Ni(OH)2. It is suggested that the film forms via a precipitation mechanism in the acid solutions subsequent to active metal dissolution. At low values of pH, this precipitated film, once formed, generally does not change in thickness as the potential is made increasingly anodic. Conversely, the Ni(OH)2 film formed in higher pH solutions (pH = 8.0 open, pH = 12.0 open and de-aerated) grows by virtue of a solid state mechanism. Both NiO and NiOOH are observed to form subsequent to Ni(OH)2 but only at higher values of pH. Although the films formed at alkaline pH values are thinner than those in the lower pH environments, they were found to be more protective.

Several statistical and iterative methods for the calculation of the retention indices of Kovats have been compared using retention data obtained on a wide range of columns. Using homologues ranging from C1 to C22 and the linear relationship between the logarithm of adjusted retention times and carbon numbers, it has been shown that the iterative method of Guardino et al. [J. Chromatogr., 118 (1976) 13] is of adequate accuracy in the majority of analyses. It has further been shown that while higher degree polynomial relationships between carbon numbers and the logarithm of adjusted retention times give improved accuracy, their interpretation is difficult.

An extensive study has been made of three methods of determining dead-times mathematically from retention data of n -alkanes. It has been shown that the linearization procedure suggested by Grobler and Balisz is sufficiently accurate for online data acquisition and that four alkanes are adequate to calculate accurately the dead-time provided that the retention times are not excessive.

The purpose of the experiments reported were to determine whether chronic treatment with either a monoamine oxidase (MAO) inhibitor or an uptake inhibitor would increase extracellular levels of 5-HT in vivo and whether such treatment resulted in a down-regulation of the 5-HT 1B -mediated decrease in extracellular levels of 5-HT. Rats were given either saline, (E)- β -fluoromethyline- m -tyrosine (MDL 72394 0.25 mg/kg p.o.) or amitriptyline (10 mg/kg p.o.) once a day for 21 days. Twenty-four hr after the final injection, dialysis loops were implanted into the frontal cortices of these rats and basal extracellular levels of 5-HT were measured. The effect of the 5-HT 1 receptor agonist 5-methoxy-3(1,2,3,6-tetrahydropyridin-4-yl)1H indole succinate (RU 24969 10 mg/kg i.p.) on the extra- cellular level of 5-HT was then studied. Basal levels of 5-HT in saline-treated rats was found to be 27.9 + 3.9 fmol/20 μl perfusate. Chronic treatment with amitriptyline had no effect on extracellular levels of 5-HT but chronic treatment with MDL 72394 significantly increased extracellular levels of 5-HT. Chronic treatment with either MDL 72394 or amitriptyline had no significant effect on the ability of RU 24969 to reduce extracellular levels of 5-HT. These results suggest that 5-HT 1B receptors are not down-regulated in response to chronically raised extracellular levels of 5-HT.

This study was designed to examine the fibrogenic and carcinogenic potentials of three smelter slags (primary copper slag, secondary copper slag, and nickel slag) that have been used for a number of years as substitutes for sand in abrasive blasting operations. Seven groups of 85 male Fischer 344 rats (approximately 180 g) were used. Each group was given a single 20-mg dose of one of the following test materials via intratracheal instillation: primary copper slag, secondary copper slag, nickel slag, feldspar, Min-U-Sil, novaculite, or vehicle control. Chemical, particle size, and surface area analyses were performed for each test dust. Animals were weighed monthly, and ten animals per group were necropsied at the 6-, 12-, and 18-mo interim sacrifices. The terminal sacrifice was conducted at 22 mo. Hematoxylin and eosin stained histologic sections were prepared from designated formalin-fixed tissues collected at necropsy and examined microscopically. The pulmonary fibrogenic and carcinogenic potentials of the three smelter slags were compared histopathologically with feldspar, novaculite, Min-U-Sil, and vehicle controls. Only minimal to slight alveolar wall fibrosis was seen in the two copper slag groups, while the response seen with nickel slag was consistent with a foreign body reaction with minimal fibrosis seen in only an occasional animal. The major reaction seen in both the feldspar- and the novaculite-treated rats was a granulomatous inflammation with varying degrees of fibrosis associated with the granulomas. Significant numbers of primary lung tumors, principally adenocarcinomas and adenomas, were seen in the copper slag (p = 0.005 and p = 0.022 for the primary and secondary slags, respectively), in the feldspar (p = 0.007), in the novaculite (p less than 0.001), and in the Min-U-Sil (p less than 0.001) groups when compared to the vehicle control group. In addition, the Min-U-Sil and novaculite groups had significantly elevated pulmonary tumor proportions relative to the other treatments (p less than or equal to 0.002), with the Min-U-Sil being higher than the novaculite (p = 0.012). On the basis of the tumor incidence data, one must conclude that both copper slags tested in this study are carcinogenic to rats.

A procedure is presented to separate diatoms and radiolaria from marine sediments and from each other, to purify them of elements associated with other phases, and to dissolve them to determine their elemental composition. The cleaning procedure eliminates artifacts due to the presence of detrital clays and the high sorption capacity of hydrated silica. The concentration of trace elements (Al, Fe, Mg, and Ba) that we find in alkaline dissolutions of clean diatoms are at least an order of magnitude lower than previously reported. The overall long-term precision in the determination of Ge/Si in a sub-standard of clean diatoms is ±0.024 × 10 −6 (1σ). Ge/Si measured in diatoms and radiolaria from core tops indicates that high-latitude Holocene diatoms accurately record the present-day oceanic Ge/Si, while radiolarian ratios are systematically lower and display more scatter. Evaluation of Ge/Si in diatoms and radiolaria from Hole DSDP 265 (Plio-Pleistocene) suggests that post-depositional alteration of the ratio does not occur at this site, but the average ratio carried by diatoms over this time interval was lower than that in the present ocean.

Comparaison des indices de retention pour des alkylbenzenes (alkyl=methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl) et des alcenylbenzenes ou des phenols-1 alcenes-1 avec deux types de phase stationnaire OV1 et LB550X

The problem of accurate determination of mathematical dead-time is discussed. A comparison of the several methods of calculation is made. The effect of small changes in retention time of n-alkanes on the calculated dead-time has been examined and reasons for inaccurate dead-time estimates are suggested.

To increase the usefulness of gas chromatography, a method qf data presentation is required that removes interlaboratory variations. All such methods require the determination of the system dead time, with the most useful being the retention index system of Kovats. This paper reviews the many theoretical, experimental and mathematical methods of estimating system dead time and evaluates their usefulness, not only in the estimation of dead time, but also in the subsequent calculation of Kovats indices. Recommendations are made as to the appropriate method to be used, and the expected accuracy in retention index values is estimated.

The passivation of Ni-30% Cu alloys in 0.15 N Na2SO4 solutions was investigated in situ at various values of pH and potential by utilizing differential reflectometry and electrochemical polarization techniques. The film responsible for passivating Ni-Cu alloy is, as was the case for pure nickel, Ni(OH)2. A mixed film, consisting of Ni(OH)2 and Cu2O has been found for pH 4, open solution, and for pH 8, de-aerated solution, both at low potentials. In the case of pH 4, de-aerated solution, de-alloying of copper has been found, particularly at anodic potentials. As a rule, the passivating film thickness for the alloy has been observed to be larger than for pure nickel (except in the case of pH 4 and 8, de-aerated solutions). The alloy was found to passivate at more anodic potentials than pure nickel and the passivating current was higher. In pH 12 solutions (open and de-aerated) both pure nickel and Ni-30% Cu behaved fairly similarly, that is, passivation occurred without active dissolution and the film thickness was nearly a linear function of the electrode potential.

1. 1. Isolated mouse TLT hepatoma chromatin has no measurable protease activity, whereas some of the chromatin fragments separated on exclusion agarose columns possess endogenous RNA polymerase activity. 2. 2. The template capacity of the template active chromatin fractions is 5–50-fold greater than usual when measured using a portion of E. coli RNA polymerase, apparently modified by purification and aging. 3. 3. Any contaminating nuclease activity in partially-purified RNA polymerase had minimal modifying effects on template capacity; the addition of pancreatic DNase but not RNase essentially eliminates the template capacity of chromatin fractions. 4. 4. Under conditions avoiding chromatin aggregation, similar template capacity patterns of chromatin fractions are obtained when the RNA incorporation reaction is executed either prior to, or subsequent to, the fractionation of the sheared chromatin.

Oligomers of ampicillin and amoxicillin were isolated by preparative chromatography on DEAE-Sephadex and purified by chromatography on Amberlite XAD-2. The purity of the oligomers was checked by thin-layer chromatography and by high-performance liquid chromatography. Proton magnetic resonance and fast atom bombardment mass spectrometry showed that ampicillin yielded mainly the dimer, trimer and tetramer, and amoxicillin the dimer, trimer and some tetramer. The corresponding penicilloates were also present. For amoxicillin an important amount of the piperazinedione was formed simultaneously.

Male CD-1 mice were castrated between 12 and 14 days of age. Between 20 and 60 days of age the development of the submandibular glands were compared with those of normal males, normal females, and sham-operated males. Although granular tubules were apparent in the normal male at 25 days and in the normal female at 35–40 days, no distinct granular tubules were observed in castrated males until 60 days of age. An extensive development of striated ducts, however, was apparent in the castrated male submandibular gland between 35 and 60 days of age. Amylase activity, observed with a starch substrate film method, was first apparent in the normal male at 25 days and in the normal female at 35 days. In each case, the reaction was localized to the granular tubules. Amylase activity increased in direct relation to the increasing differentiation of granular tubules. In the prepubertally castrated male, weak amylase activity was detectable at 30 days in some striated ducts. This activity increased slowly up to 60 days, the age at which the granular tubules first appeared. Although the submandibular glands of castrated males and normal females appeared generally similar in morphology and amylase activity by 60 days of age, the achievement of these similarities had been attained by distinctly different patterns of development in the two groups.

Hydrogen content effect on annealed and work hardened palladium wire tensile properties, determining yield/tensile stress and elongation

The submandibular gland of the Chilian rodent, Octodon degas , was studied histochemically with Alcian blue, Azure A, toluidine blue, PAS with diastase controls, and a starch substrate film method for amylase. Granular tubules were well developed in both males and females. The acini were amylase-positive. There were no apparent sexual differences in amylase activity. The Alcian blue and Azure A reactions, in addition to toluidine blue metachromasia, indicated that the acini were also acid mucosubstance-positive. The granular tubules were negative for both acid mucosubstances and amylase. The PAS reaction was intense in male acinar cells and moderate in female acinar cells. The granular tubules had a faint PAS reaction.