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991.
A specially designed tube viscometer was used to measure apparent viscosity during flow of Bologna type sausage emulsions moving through a pipe. Emulsions varied in fat content (from 21.8 to 44.3%) and in moisture/protein ratio (from 3.7 to 5.6), and the effects of added sodium chloride, sodium diphosphate, starch and blood plasma were investigated in a 36% fat, 3.7 moisture/protein emulsion.
The shear stresses determined as a function of shear rate were fitted by a power law. Yield stress of the emulsions was negligible relative to the applied stress. However, inspection of the flow profiles indicated that considerable slip of the sausage emulsion occurred at the pipe wall. Both emulsion flow and slip contribute to overall flow behaviour, so a kind of effective viscosity is determined. Intrinsic rheological properties and wall slip will both be affected by the composition of the sausage emulsion.  相似文献   
992.
The effects of several modified atmospheres (100% O2, 100% N2, 100% CO2+ O2 scavenger, and 25% CO2 9% N2 66% O2) and vacuum on the color stability of turkey were studied. Microbiological examinations were performed at days 0, 7, 14 and 21. pH and pigment content measurements were performed at days l and 2, respectively. Color coordinates were determined at intervals of 2, 5, 7, 11, 14 and 21 days storage in the CIELAB system (1976). Meat kept under vacuum and 100% CO2+ O2 scavenger treatment showed the highest a* values color stability (p < 0.05) and the lowest rate of myoglobin oxidation (p < 0.05). The level of microbiological contamination of turkey breast meat stored with 100% CO2+ O2 scavenger was the lowest. Conditioning breast turkey meat with 100% CO2+ O2 scavenger or under vacuum would improve the color stability during storage.  相似文献   
993.
Dichotic listening procedures have been used to assess cerebral lateralization in normal Ss. One particularly useful technique is the use of stimuli that fuse into a single percept. Although this procedure has many advantages over other dichotic listening methods, it is particularly susceptible to stimulus dominance, which acts as noise in a S's response data, thus reducing the power of any statistical test of the ear advantage. It is proposed that the solution to this problem is a log-linear analysis of the response data to yield a λ-type index (λ*) that is a measure of ear dominance independent of stimulus dominance. Details of the analysis are provided, as well as a sample analysis of data collected from 104 right-handed and 30 left-handed Ss. Comparisons are drawn between the log-linear analysis and other methods that have been proposed to control for stimulus dominance in this single-response dichotic fusion procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
994.
It is shown how very simple velocity-tracking robust controllers for permanent magnet motors driving nonlinear loads can be designed based on variable structure systems techniques. Very fast dynamics, accurate and robust velocity-tracking are achieved with very simple hardware components without resorting to powerful digital signal processors and related interface hardware. A cascade control structure is used to ensure maximum flexibility. The controller for a DC motor is considered in great detail. Extension to AC synchronous PM motors is also presented. At the different control levels robustness is addressed with specific algorithms and the simplest solution is always selected. The controller architecture for both DC and AC synchronous motor are presented and discussed in the paper. Experimental results related to the control of a DC motor driving a nonlinear load are also shown. They demonstrate feasibility and excellent performances of the proposed approach  相似文献   
995.
This paper presents the state of the art in the control of robotic manipulators in constrained motion tasks. Contact control concepts are classified using different criteria, and their main characteristics are analyzed. For each of the presented contact control concepts, the essential characteristics are stated. The paper covers some early ideas and their later improvements, as well as trends in this field. The advantages and drawbacks of the various control schemes are outlined, and they are compared from the standpoint of their implementation issues. In the paper, all characteristic results in the stability analysis of robotic manipulators in the constrained motion tasks are briefly reported. A new approach to the correct solution of contact tasks control is mentioned as well  相似文献   
996.
This paper proposes a new method to describe and identify a 3-D curved object for the purpose of validating a fabricated object to the design specification. Curved 3-D objects are, in general, difficult to represent and identify because they lack distinct properties such as edges, planes, or cylindrical surfaces which are the building blocks in representing objects. In this paper, the authors propose to use principal axes of a 3-D object to establish a reference for the representation. A method of obtaining an inertia matrix from a 3-D range image is developed. The unique set of principal axes is obtained from the inertia matrix of an object with an arbitrary 3-D position and orientation, and the object can be described uniquely on these principal axes. On the principal axes, an object is described by a set of features describing the shape of the object such as spine, section size, section orientation, and section contraction. The features are used for comparing two objects for the validation purpose. The authors also propose a direct measure of similarity between two objects as a mean-squared difference of radii. As an experiment, two 3-D object models are designed through a CAD package, and fabricated objects are compared with the designed models for validation purposes  相似文献   
997.
A boost type converter is described that is suitable for low-voltage DC-supply of fluorescent lamps. It has inherent lamp current limitation (ballast action) and provides the high voltage pulses and electrode heating that are required for igniting the lamp. The proposed circuit is applicable in automotive, emergency, and portable light sources.<>  相似文献   
998.
Power semiconductor devices find wide application in modern power electronic converters. Protection of these devices against overload/short circuit conditions is of paramount importance. Present day protection topologies employing different circuits have invariably one main drawback in that the fault current reaches the set value before action is initiated to trip the system. This poses a severe stress on the device. Hence an adequate safety margin has to be necessarily provided to prevent excessive device stresses and care has to be taken to see that the device is operated well within its safe operating areas. The present paper proposes a method wherein the slope or rate of rise of the fault current is detected and once the slope exceeds the set reference, action is initiated to trip the system much before the fault current reaches dangerous levels. The method provides a fast means of detection of overload and short circuit currents and can be conveniently adopted for the protection of devices in power transistor/IGBT based inverters against short circuited load conditions or shoot through faults. The possible reduction of stresses in the power devices are also highlighted  相似文献   
999.
The bistable field effect transistor (BISFET) is a novel inversion-channel switching device exhibiting abrupt current transitions and hysteresis in its output characteristics. The semiconductor structure of the BISFET is compatible with a range of electronic and optoelectronic devices. In this work, integration of a BISFET with an LED is reported. Both devices have been implemented on a single semiconductor substrate using a single fabrication sequence. The BISFET is used to current drive the LED. Abrupt transitions and hysteresis are seen in the optical output from the circuit in the range of gate voltage from 1.75 V to 1.9 V  相似文献   
1000.
In this paper, an analytic current-voltage model for submicrometer fully-depleted (FD) silicon-on-insulator (SOI) MOSFET's is presented. This model takes into account the source/drain series resistances which can be especially high in thin film SOI devices. The effect of drain induced conductivity enhancement is also included, which is important for submicrometer channels. The model is verified by comparison to measured SOI I-V characteristics. Good agreement is obtained for SOI film thicknesses ranging from 40 to 220 nm and effective channel lengths down to 0.25 μm  相似文献   
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