Laboratory Furnace for Studies in Controlled Atmospheres; Melting Points of MgO in a N2 Atmosphere and of Cr2O3 in N2 and in Air Atmospheres

An induction furnace design which readily permits the determination of melting points and basic phase studies is described. The melting point of MgO was redetermined to be 2825°C., and the melting point of Cr₂O₃ is reported as 2330° and 2315°C. in air and in nitrogen atmospheres, respectively.     

COMPARISON OF MULLER-KAUFFMANN'S TETRATHIONATE BROTH AND MODIFIED RAPPAPORT'S MEDIUM FOR ISOLATION OF SALMONELLA

Results obtained with tetrathionate broth (TBB) using the standard method and Rappaport-Vassiliadis medium (RV) did not differ markedly with respect to the proportion of positive samples or the sero- and phage types of salmonellae isolated from minced beef and pork. TBB, based on the commercial dehydrated medium of Oxoid (CM 343), gave fewer positive samples while that of Merck (Art. No. 5172) was equivalent to RV. In individual experiments results were sometimes markedly different. Results obtained for reference samples of minced meat, with salmonellae added, demonstrated that the chances of detecting salmonellae increase with increasing numbers present initially. At the same time it was also demonstrated that the presence of minced meat and its competing microflora have an unpredictable effect on the detection of salmonellae.     

1,4-Dihydroxyanthraquinone-2-thioethers. Dyes for Synthetic-polymer Fibres

The synthesis of a series of 2-thioethers of 1,4-dihydroxyanthraquinone by various preparative routes is described. The colour, dyeing and fastness properties on synthetic-polymer fibres of these dyes is discussed in terms of the nature of the substituent in the thiol group. 2-(2-aminophenylthio)-l, 4-dihydroxyanthraquinone, which gave the new heterocycle 6,13-dihydroxyanthra-[2,3-b]benzo[d] thiophen-7,12-dione on Pschorr intramoleadar cyclization, was observed to undergo cyclization, during both its synthesis and its application to polyester fibres, to the blue coloured 7-hydroxy-14H-mphtho[2,3-a] pheno-thiazine-8,13-dione.     

Synthesis and Electronic Spectra of some 4–Aminoazobenzenes

The synthesis of a range of monoazo disperse dyes prepared from monosubstituted anilines as the diazo components is reported The absorption maxima of the dyes are recorded, and shifts resulting from the effect of different substituents in both the diazo component and the coupling component are correlated with the nature of the substituent. The use of monosubstituted aniline; as diazo components, coupled to different TV–substituted anilines, can result in dyes with λD_max differing by about 100 nm.     

直喷式柴油发动机缸内三维温度场的计算与试验

为计算直喷式柴油发动机缸内燃烧温度,提出利用理想混合比质量分数空间来计算缸内温度场.通过引入混合比质量分数基本概念,推导出各种组分与混合比质量分数的关系.通过引入小火焰的假设,分析典型非预混合小火焰结构,推导出绝热状况下缸内温度与混合比质量分数的关系.在理想混合比质量分数空间坐标系下建立新的温度输运方程,提供一种将湍流化学反应场和湍流运动场分离开的方法.经过一系列参数的输入,计算出缸内温度与扩散尺度速率关系,缸内温度与混合比质量分数关系以及缸内火焰温度分布,试验验证了计算结果.为计算直喷式柴油发动机缸内燃烧温度以及污染物成分提供新的计算方法.     

Scanning microphotolysis: A new photobleaching technique based on fast intensity modulation of a scanned laser beam and confocal imaging

The fluorescence photobleaching method has been widely used to study molecular transport in single living cells and other microsystems while confocal microscopy has opened new avenues to high-resolution, three-dimensional imaging. A new technique, scanning microphotolysis (Scamp), combines the potential of photobleaching, beam scanning and confocal imaging. A confocal scanning laser microscope was equipped with a sufficiently powerful laser and a novel device, the ‘Scamper’. This consisted essentially of a filter changer, an acousto-optical modulator (AOM) and a computer. The computer was programmed to activate the AOM during scanning according to a freely defined image mask. As a result almost any desired pattern could be bleached (‘written’) into fluorescent samples at high definition and then imaged (‘read’) at non-bleaching conditions, employing full confocal resolution. Furthermore, molecular transport could be followed by imaging the dissipation of bleach patterns. Experiments with living cells concerning dynamic processes in cytoskeletal filaments and the lateral mobility of membrane lipids suggest a wide range of potential biological applications. Thus, Scamp offers new possibilities for the optical manipulation and analysis of both technical and biological microsystems.     

DEPOSITION OF SUBMICRON AEROSOL PARTICLES DURING INTEGRATED CIRCUIT MANUFACTURING: THEORY

ABSTRACT

Submicron (≤1μm) particle contamination can produce unacceptably low yields in the manufacture of integrated circuits. Calculations were made to predict deposition velocities of 0·01-lOμm particles, incorporating gravitational, dlffusional, and electrostatic effects. The results were summarized in equations that correlate non-dimensional deposition (Sherwood number) with convective-diffusion (Peclet number) and with electrostatics (Boltzmann and Fuchs charge distributions). These equations were used In conjunction with particle size distributions to predict particle deposition. In a companion paper |25| the predictions were shown to compare well with limited experimental data. To reduce deposition product surfaces should not be electrically charged and, where possible, these surfaces should be at higher temperatures than the ambient gas. For quality control purposes, the deposition flux predictions could serve to link the specifications of gas cleanliness with the specifications of surface cleanliness.     

Environmental Fluid Catalytic Cracking Technology

The fluid catalytic cracking (FCC) process converts heavy oil into voluable fuel products and petrochemical feedstocks. Environmental regulations are a key driving force for reducing FCC process air-pollutant emissions and for changing the composition of fuel products. Environmental considerations are affecting the design and operation of the FCC and are providing opportunities for the development of in-process additives. The present article reviews developments in these environmental technologies.     

Effect of pH and prefreezing treatment on the texture of yellowtail rockfish (Sebastes flavidus) as measured by the Ottawa Texture Measuring System

Texture is very important to the organoleptic quality of fish products. Poor frozen storage conditions or improper prefreezing treatment can result in unacceptably tough fillets. With some species, undesirable soft, mushy texture develops during chill storage.
This study is concerned with the influence of treatment prior to freezing (samples were frozen pre-rigor, in-rigor, post-rigor and after 6 days' chill storage in ice or refrigerated sea water) on the texture of yellowtail rockfish stored frozen as whole gutted fish or as fillets. The effect of pH was also studied. Texture was measured objectively using the Ottawa Texture Measuring System on samples stored for 6 months at −28°C.
A very good negative correlation was found between pH level and toughness as measured using a Kramer shear-compression cell in the Ottawa Texture Measuring System. Fish stored in refrigerated sea water prior to freezing were appreciably more tender. There was no statistical difference in texture (shear press force) values between samples stored as whole fish versus samples stored as fillets.