RELATIONSHIP BETWEEN COMPOSITION AND STABILITY OF SAUSAGE-TYPE EMULSIONS

SUMMARY— A laboratory technique for the preparation of small batches of sausage emulsion was developed for a comparative study of the effectiveness of fresh and frozen beef in achieving emulsion stability. The technique consisted of three basic steps: (1) low speed chopping and blending of ingredients at −2° to +2°C; (2) low speed blending with the gradual addition of soybean oil at 2°−8°C; and (3) high speed chopping to a temperature of 15°-16°C. The preparation and evaluation of emulsions with widely varying compositions revealed that the lean and fat percentages could be varied over wide ranges without significantly affecting emulsion stability, but the range for percentage of water was narrow and critical to stability. The relative stability for fresh and frozen lean was influenced by the amount of added water. For example, at 30% fat level, there was a sharp drop in stability as the added water was reduced below 16% for fresh beef; whereas, an equivalent drop in stability was found as the added water was reduced below 21 % for frozen beef. The theory is proposed that emulsion instability is highly dependent upon the level of added water based on results of this investigation.     

Particle Deposition in the GE90 Pyrometer Purge Air System

This paper investigates the flow field and particle trajectories in the GE90 pyrometer purge air design in order to illustrate the fouling mechanism that drives the deposition of particulates onto the lens. It is shown that the predominant flow feature within the purging system is a swirl pattern that develops at the mouth of the unit's still tube. This feature has the ability to draw contaminant particles into the still tube and thus significantly increase the likelihood of particle deposition resulting in optical fouling of the pyrometer's optics.     

Solid state interfacial reactions in electrodeposited Cu/Sn couples

Cu/Sn couples, prepared by sequentially electroplating Cu and Sn layers on metallized Si wafers, were employed to study the microstructures, phases and the growth kinetics of Cu-Sn intermediate phases, when electroplated Cu/Sn couples were aged at room temperature or annealed at temperatures from 373 K to 498 K for various time. Only Cu6Sn5 formed in aged couples or couples annealed at temperature below 398 K. The Cu6Sn5 layer was continuous, but not uniform, with protrusions extending into the Sn matrix. W...     

Microstructural analysis of Pd/Pt/Au/Pd ohmic contacts to InGaP/GaAs

Microstructural evolution during the annealing of Pd/Pt/Au/Pd p-ohmic contacts (with and without a thin layer of Zn) to InGaP/GaAs HBTs has been studied using transmission electron microscopy (TEM). Metal layers were deposited by electron beam evaporation directly onto the InGaP emitter layer with the intention of consuming the InGaP during annealing to contact the heavily C-doped p-type GaAs (3×10¹⁹ cm⁻³) base layer below. Initial reaction between Pd and Pt and InGaP formed a five-component amorphous layer (Pd, Pt, In, Ga and P), which crystallized to (Pt_xPd_1−x)5(In_yGa_1−y)P (0≤x, y≤1) at the interface between Pt and the amorphous layer. Annealing at temperatures ≥415°C caused complete decomposition of the InGaP and partial decomposition of the GaAs base layer, producing a contact consisting of (Pt_xPd_1−x)5(In_yGa_1−y)P, PtAs₂ and PdGa. The attainment of low contact resistances did not depend on the presence of Zn. Minimum values of 0.10−0.12 Ω mm were achieved after annealing at 415–440°C for contacts both with and without Zn. This revised version was published online in July 2006 with corrections to the Cover Date.     

THE MEASUREMENT OF EMULSIFYING CAPACITY BY ELECTRICAL RESISTANCE

SUMMARY— A method was developed to objectively measure the emulsifying capacity (ECJ of meat and fish protein extracts by electrical resistance. The method of Swift et al. (1967) was modified to deliver oil at a constinuous rate at the point of blender agitation, thus forming an emulsion for testing the validity of the electrical resistance method. This modification reduced the variance of the end-point determination within samples. The precision of end-point determinations by electrical resistance was equivalent to the modified visual method, and had the advantages of being objective, having a finite end-point and providing a continuous record of the emulsion during formation and collapse. The EC of fresh muscle slurry extracts from fish were higher than those from beef and pork. However, the EC of fresh muscle supernatant extracts ranked from highest to lowest are beef, fish and pork, respectively. In all cases, the EC of supernatant and fresh muscle extracts was higher than the slurry and frozen muscle extracts, respectively.     

Solid state interracial reactions in electrodeposited Cu/Sn couples

Cu/Sn couples, prepared by sequentially electroplating Cu and Sn layers on metallized Si wafers, were employed to study the microstructures, phases and the growth kinetics of Cu-Sn intermediate phases, when electroplated Cu/Sn couples were aged at room temperature or annealed at temperatures from 373 K to 498 K for various time. Only Cu₆Sn₅ formed in aged couples or couples annealed at temperature below 398 K. The Cu₆Sn₅ layer was continuous, but not uniform, with protrusions extending into the Sn matrix. When Cu/Sn couples were annealed at temperatures from 423 K to 498 K, two continuous and uniform Cn₆Sn₅/Cu₃Sn layers formed within the reaction region between Sn and Cu. There were many voids near the Cu₃Sn/Cu interface and within the Cu₃Sn layer. Cu₆Sn₅ and Cu₃Sn formations both follow parabolic growth kinetics with activation energies of 41.4 kJ/mol for Cu₆Sn₅ and 90.4 kJ/mol for Cu₃Sn, respectively.     

电沉积Ag／Sn偶界面反应及其动力学

采用扫描电子显微镜(SEM)、电子能谱仪(EDS)、X射线衍射仪(XRD)对室温时效及125～225 ℃热处理的电沉积Ag/Sn偶反应区结构及相组成进行分析,研究Ag/Sn界面固相反应的动力学过程.研究表明:在刚电沉积的Ag/Sn偶中发生Ag/Sn界面固相反应,形成Ag3Sn;在室温时效过程中Ag3Sn层生长缓慢,但随着热处理温度的提高(125～200 ℃),Ag3Sn层生长速率显著提高;Ag/Sn界面固相反应为一扩散控制的反应过程,反应的激活能为70.0 kJ/mol.     

Performance of Pd–Ge based ohmic contacts to n-type GaAs

The performance of Pd–Ge based ohmic contacts, with and without Ti–Pt or Ti–Pt–Au capping layers, has been investigated. The contacts were deposited by electron beam evaporation, then characterized electrically using a modified transmission line method (TLM) and structurally using both cross-section and plan-view transmission electron microscopy (TEM). Although both capped and non-capped contact structures underwent the same phase transformations during annealing, capped contacts had significantly better contact resistances (a minimum value of 4×10-7 Ω cm² was achieved) – almost three orders of magnitude better. The superior performance is attributed to the capping layers providing protection for the Pd–Ge layers during contact processing, where the metallization was exposed to a CF₄–O₂ plasma, oxyen descumming, organic solvents and deionized water. Non-capped contacts exhibited PdGe decomposition and oxidation of exposed Ge. Long-term reliability testing of capped contacts showed virtually no change in contact resistance at 235°C (1350 h) and a sevenfold increase after ageing at 290°C for 370 h. There were no phase changes during ageing; the increase in contact resistance was attributed to interdiffusion between Ge and GaAs. This revised version was published online in July 2006 with corrections to the Cover Date.