Model system evaluations of the effects of different levels of K(2)HPO(4) NaCl and oil temperature on emulsion stability and viscosity of fresh and frozen turkish style meat emulsions

The effects of different levels of K(2)HPO(4), NaCl, and the effects of oil temperature used in the evaluation of emulsion stability and viscosity of fresh and frozen beef (fat level adjusted with tail fat from sheep) was studied by utilizing a model system. Emulsion stability (ES) and emulsion viscosity (EV) of frozen meat tissue were both decreased, by 3·6% and 10·5% respectively, when compared to fresh meat. ES was decreased by 4·0% and 3·7% at 5°C and 11°C oil temperature respectively when compared to 21°C. While EV decreased 12·2% at 11°C compared to 21°C, it did not show any statistically significant (P < 0·01) change at 5°C oil temperature. ES and EV were elevated with the addition of phosphate and increasing phosphate levels. These increases for ES were 3·9% and 3·7% with 0·50% and 0·75% phosphate levels respectively, when compared to the 0·00% phosphate control group. Also, the increases for EV were 22·3% and 27·0% with 0·50% and 0·75% phosphate levels respectively, compared to the 0·00% phosphate control group. The alteration of the ES was not statistically P < 0·01) significant for the 0·50% phosphate level when compared to the 0·75% phosphate level. The ES decreased 1·1% for a 3·0% salt level when compared to a 2·5% salt level, and there was statistically (P < 0·05) no effect on the EV.     

Tenderness of ovine semimembranosus: Is collagen concentration or solubility the critical factor?

The concentration and heat-dependent solubility of collagen were measured in the semimembranosus (36 animals) and, for comparison, the gluteus (108) muscles of sheep aged 4 months to 5 years. For both muscles, solubility declined with age but concentration remained unchanged. Compared to gluteus and other major ovine muscles, the semimembranosus had markedly insoluble collagen at a relatively low concentration. To assess the relative importance of collagen concentration and solubility on tenderness/texture for a muscle with this profile, the semimembranosus muscles contralateral to those used for collagen analysis were cooked to an endpoint of 75°C and assessed by sensory panel and Warner-Bratzler shear tests. The panel data showed that collagen concentration was the more important determinant of eating quality, whereas shear data were more clearly related to solubility. The implications of the sensory results are discussed for muscles that contain a different collagen profile.     

The effect of preheated tendon as a lean meat replacement on the properties of fine emulsion sausages

Tendon from beef hind leg muscles was used to replace some of the lean in a conventional emulsion formulation. The tendon was homogenized and either used raw or preheated for 2·5 h at a range of temperatures (50, 60, 70, 80°C) before use. Texture analysis and sensory evaluation were performed on cylinders of cooked sausage. Texture analysis was carried out on formulations which had 20% of meat protein replaced by 20% tendons which were raw or had been preheated to 50, 60, 70, or 80°C. Fracturability decreased by about 40% with raw tendon, but was restored to within 20% of the no-replacement control if the tendon had been preheated. Hardness was approximately doubled by replacement with raw tendon or tendon heated at 50°C. At temperatures higher than that, hardness returned to approximately no-replacement levels. For sensory evaluation (0-25% replacement; preheating at 70°C), sausages were assessed by a 12-member panel for texture, flavour and overall acceptability. All attributes decreased with increasing collagen content, the decrease being less marked with preheated tendon. Thus more connective tissue could be added for the same panel score if the tissue was preheated. Comparison of the texture profile and the panel scores for texture at the same lean replacement level suggested that reduced fracturability was the texture parameter that panellists objected to when heated tendon replaced some of the lean. Other researchers have shown that connective tissue preheated to 100°C before addition in emulsion sausages results in improved yields and better sensory attributes, but the present results show that temperatures as low as 60°C can be effective for beef tendon.     

Measuring active wood fracture surfaces

This report describes a measurement method, based on image processing, for calculating the proportion of active wood fractures in a sheet of particle board that has been pulled apart. This method gives an indirect measurement of the effectiveness of the glue in a particle board. The basic procedure is to separate different surfaces on both sides of the tensile fracture. The separation of the glue covered surfaces from wood surfaces has been enhanced by a development process. The separated surfaces for each side, represented in the form of a binary image, are added, and a proportion of the surface with coinciding wood surfaces represents the proportion of wood fractures. The error analysis covers the randomly obtained coinciding surfaces.     

Optimization of Carrot Juice Color and Cloud Stability

Investigations were conducted on the effects of heating, acidification, and enzyme treatment on carrot juice color and cloud stability. Heating whole carrots to 93°C prior to milling and pressing improved juice color, but reduced juice yield compared to heating milled carrots to 93°C. Juice color was improved by acidification of milled carrots to pH 5 or 4 with citric acid prior to pressing. Juice from carrots heated before milling clarified quickly if not acidified before pressing. Acidification after juice extraction did not stabilize cloud. A commercial pectinase/hemicellulase preparation improved juice color, but not juice yield. Only 20% of potential β-carotene was extracted from carrots during pressing, and β-carotene was extracted to a greater extent than α-carotene.     

Thermionic arc breakdown in small discharge gaps: model andapplications

A model for thermionically induced breakdown is developed which predicts the voltage levels experienced in low-voltage discharges. Initially, electron emission across an active discharge minigap must be established. Prior to breakdown, emitted electrons populate the cathode space-charge region and the remaining gap is unionized. Breakdown criteria and a means for estimating the reduced breakdown voltage in the bulk gas are derived in terms of conventional Townsend ionization mechanisms, wherein multistep or cumulative ionization must be active. Since the cathode space-charge region is replete with emitted electrons, positive ions traversing it release to the bulk gas considerably more electrons than would be available with the conventional Townsend γ mechanism at the cathode surface. This equivalently higher γ significantly shifts the Paschen curve toward lower minima. One practical thermionic assisting device is a tungsten light-bulb-grade filament, which shunts the primary discharge electrodes and, within the filament's minigaps, breakdown occurs. Thermionic arc breakdown has been implemented in the starting of arc devices for lamps and in thermionic power converters; an application to ionization chambers in electrostatic thrusters is also discussed     

Discussion of “Transmission equipment reliability data fromCanadian Electrical Association” [and reply]

The original paper “Transmission Equipment Reliability Data from Canadian Electrical Association” by D.O. Koval (see ibid., vol. 32, p. 1431-9, 1996) presents transmission equipment reliability data collected by the Canadian Electrical Association (CEA) during the period 1988-1992, Historic reliability data are sometimes unavailable or difficult to obtain. The author argues that, keeping this in mind, one can easily see the usefulness of this paper in the task of reliability analysis of transmission systems. Based on the data presented, a number of comments are given as is the original author's reply     

Electronic lighting interference

This article presents empirical laboratory and field data documenting electromagnetic interference between high-efficiency electronic lighting and certain other electronic devices. Typical equipment involved are power-line carrier systems, security systems, and remote controls for televisions and VCRs. Reported cases involving both electronic lighting emissions and immunity in building power systems are summarized according to basic interference mechanisms. To illustrate the potential complexities of this problem, the article describes a case where high-efficiency lighting interfered with a hearing aid. The discussion of the case includes a field survey, laboratory investigations, and recommended solutions to the problem. To conserve energy, electric utilities have carried out demand-side management (DSM) programs that include installing electronic lighting in commercial and government buildings. Millions of electronic ballasts and compact fluorescent lamps (CFLs) have been installed. Several cases of new electronic lighting interfering with other appliances have been documented and are being studied by the Electric Power Research Institute (EPRI) Power Electronics Applications Center (PEAC). This research will help to determine how appliances interact with radiated and conducted emissions from ballasts. Although these cases do not represent a large percentage of installations, lighting manufacturers have risen to the challenge of identifying design solutions to several of the problems that have been identified.     

Positive streamer propagation in large oil gaps: electricalproperties of streamers

This paper presents experimental data and calculations concerning the electrical properties of positive streamers in mineral oil at large gaps and HV. The experiments concern the measurement of charge, electric field, and the determination of the potential drop along streamers, either in the liquid alone, or for streamers guided within insulating tubes. Calculations of charge and field distribution around streamers are carried out by charge simulation. To do this, streamers are represented by objects with simple shapes (spheres or cylinders) equivalent to their macroscopic aspect. These models lead to a correct agreement with measured streamer charge and field on the plane electrode. Qualitative correlations are established between calculated field distributions and streamer behavior such as velocity, transitions between propagation modes. It is also concluded that the potential drop in streamers and branching both act as regulating mechanisms that help to keep the streamer tip field, and hence the velocity, constant over a wide voltage range     

A synchronous generator fuzzy excitation controller optimallydesigned with a genetic algorithm

Design of a fuzzy logic power system controller with satisfactory performance is not an easy task. The difficulties come from two aspects. First, design of a fuzzy logic controller mainly uses the experience of the human experts. To acquire enough heuristic knowledge from the domain experts and to represent this kind of knowledge appropriately with a set of fuzzy rules present difficulties. Second, it is difficult to appropriately tune the parameters used in the fuzzy logic controller. These parameters are commonly determined by a “trial and error” method which is rather time consuming. In this paper, genetic algorithm is introduced to design an optimal fuzzy logic controller. The proposed method has been used to design an optimal fuzzy logic excitation controller for a generating unit. Test results with the fuzzy logic controller show very satisfactory results