Elimination Of Spots Research Articles

Elimination of Outdoor Wireless Services Coverage Blind Spot by Use of Flat Metallic Reflector

Outdoor wireless services quality is greatly tarnished by the existence of coverage blind spots or any areas of inadequate reception. It is thus of interest to eliminate or fill in the blind spots in order to boost the receiving signal strength which ultimately leads to better service quality. The authors propose the use of a simple flat metallic reflector as a device to divert some energy in the service coverage towards the blind spots or any existing areas of inadequate reception. The method of moment is employed in analysing the effectiveness of the authors' proposed technique. Experiments have been carried out to verify calculation results as well as to find out on the proposed technique's viability. It is found that the elimination of blind spots by using a reflector is a viable approach. The received power at the blind spot locations are increased by about 3 dB to 5 dB when the reflector is present.

A novel low cost texturization method for large area commercial mono-crystalline silicon solar cells

Texturization of mono-crystalline silicon for solar cell fabrication is still a key issue due to consumption of large amount of costly isopropyl alcohol (IPA) in conventional NaOH/KOH solution. The need of IPA arises due to the improvement in the uniformity of pyramidal structures and elimination of spots caused by bubbles sticking on the wafer surface during the texturization process. We investigated a new texturization technique for mono-crystalline silicon solar cells with tribasic sodium phosphate (Na 3PO 4, 12H 2O) solution with much less amount of IPA. The proposed texturization method of this paper is cost effective due to reduction in the consumption of expensive IPA. The cost comparison of our novel texturization approach with conventional NaOH texturization has also been reported in this paper. We are reporting for the first time such a novel approach of using tribasic sodium phosphate for texturization of mono-crystalline silicon surface with which solar cells of efficiency 14–14.8% are fabricated with more than 90% yield.

Negative Temperature Programming Using Microwave Open Tubular Gas Chromatography

A microwave gas chromatography (GC) column oven is engineered to generate a uniform microwave field around an open tubular column with the elimination of cold spots, which are common in a domestic microwave oven. Short cool-down time in microwave heating makes it possible to employ negative temperature programming for the enhanced separation of compounds during the process. The feasibility of negative temperature programming in microwave GC is investigated for the analysis and quantitation of four different pairs of nonvolatile and volatile compounds. The influence of intermediate column cooling rate, holding time in the cooling ramp, and reheating rate after the cooling ramp for enhanced resolution are investigated. The results obtained from negative temperature programming are compared with those from positive temperature programming. Negative temperature programming affords greater resolution of some critical pairs of analytes.

A neural network approach to identify forest stands susceptible to wind damage

The artificial neural network technique to model wind damage to forests was examined. The network used in the investigation was a three-layered feed-forward neural network with a backpropagation training-algorithm using a momentum term and flat spot elimination. To yield insights into the performance of the network, a logistic regression model was fitted as a baseline. Two different types of models were set up and analyzed for both approaches. A dichotomous model that predicted the categories “damaged” versus “undamaged” for two different damage thresholds and a multinomial model that predicted the damage in four damage classes. The performance of the network and the logistic regression model was measured using the mean squared sensitivity error. The results of the dichotomous model demonstrate that a feed-forward network is able to better classify forests susceptible to wind damage than a logistic regression model, especially when the frequency of the undamaged and damaged forest stands differs significantly. This study also shows that the network has a higher capacity to identify damaged forest stands, compared to the logistic regression model applied in this investigation. With the specific dataset used in the present study, the proportion of damaged forest stands predicted by the network was between the observed proportion and the proportion predicted by the logistic regression model. The results of the multinomial models showed that both, the statistical model and the neural network were unable to classify all four damage classes but showed a dichotomous behavior in predicting the damage only in the two extreme damage classes. Possibilities to optimize the network performance by using different training algorithms or topologies and principal differences between the two models referring to their specific properties are discussed.

Proximity correction simulations in ultra-high resolution x-raylithography

This paper follows previous demonstrations of demagnification by bias in ultra-high resolution proximity x-ray lithography. The demagnification, ×1-×6, is achieved without lenses or mirrors. Two-dimensional proximity corrections, applied to rectangular mask shapes, are simulated. A V-shaped inrigger, cut into the mask, is particularly effective. When a typical range of broadband illumination wavelengths is used, several beneficial effects are observed when the gap is held at the `critical condition'. Maintaining fine resolution, oscillations - due to Fresnel diffraction parallel to the longer dimension of a rectangle - are virtually eliminated, and the image intensity is made uniform by the elimination of bright spots near the ends of a rectangle.

The Interchangeability of Learning Rate and Gain in Backpropagation Neural Networks

The backpropagation algorithm is widely used for training multilayer neural networks. In this publication the gain of its activation function(s) is investigated. In specific, it is proven that changing the gain of the activation function is equivalent to changing the learning rate and the weights. This simplifies the backpropagation learning rule by eliminating one of its parameters. The theorem can be extended to hold for some well-known variations on the backpropagation algorithm, such as using a momentum term, flat spot elimination, or adaptive gain. Furthermore, it is successfully applied to compensate for the nonstandard gain of optical sigmoids for optical neural networks.

Reduction of surface defects in the production of HDG-DDQ steel for automotive use

The present paper describes the main measures adopted to improve the surface quality of hot dip galvanized (HDG) steels on llva galvanizing lines (Sendzimir type, horizontal furnaces).Improvements of coating adhesion and elimination of bare spots are achieved by the control of strip contamination, its temperature furnace atmosphere, zinc bath composition. Ripple and drop-mark defects are avoided by optimization of line speed, wiping pressure and distance, base steel roughness and zinc coating weight.Further improvements are expected.

Droop: a rapidly computable descriptor of local minimum tissue temperature during conductive interstitial hyperthermia.

Although the goal of local hyperthermia therapy for cancer is to elevate the temperature of a tumour to cytotoxic levels, without the presence of 'cold spots', varying blood flow has made the achievement of consistent, therapeutic temperature distributions extraordinarily difficult. The paper presents a novel approach to estimating local minimum tumour temperatures during conductive interstitial hyperthermia which facilitates identification and elimination of cold spots. Conductive interstitial hyperthermia is modelled mathematically for a parallel array of implanted, electrically heated catheters which warms the treated tissue by thermal conduction and blood perfusion. Computer simulations employing the bioheat transfer equation reveal a predictive relationship between implanted catheter temperature, catheter power, implantation geometry and local minimum tumour temperature. Formulation of this relationship in terms of a parameter named 'droop' allows estimation of local minimum intratumoural temperatures from individual catheter temperature and power. Computer simulations are also performed to determine the sensitivity of the droop-based estimator to variations in properties of the tissue and catheters. Generally, variations in geometry or thermal properties of about 10 per cent cause estimation errors of less than 1 degree C in magnitude. These results suggest that online estimates of thermal 'droop' may provide a practical route to more consistent control of intratumoural minimum temperature during conductive interstitial heat therapy.

Dioxin emissions: Possible techniques for maintaining the limit of 0.1 ng TE m −3 (as of 1990/91)

Processes which will achieve up to 100-fold reduction of exhaust gas emissions of dioxin as proposed for the new German Standards are reviewed. A combination of processes which remove fly ash, NO x, SO x, HCl and other pollutants will also remove dioxins. Reduction of chlorinated compounds fed to the incinerator is not likely to make any significant difference. Good turbulence with elimination of cold spots in the firebox will ensure initial thermal destruction. Dioxins are synthesized on fly ash particles at temperatures between 200 and 400° C. Rapid temperature reduction across this range by water injection will greatly reduce dioxin levels. Catalytic inhibitors can also be used. Since dioxin is adsorbed on fly ash, efficient scrubbing is essential for high removal efficiency. Sorption on active carbon beds is also being evaluated.

Dioxin Emissions: Techniques for Maintaining the Limit of 0.1 ng Te m-3 (as of 1990/91)

Processes which will achieve up to 100-fold reduction of exhaust gas emissions of dioxin as proposed for the new German Standards are reviewed. A combination of processes which remove fly ash, NOx, SOx, HCl and other pollutants will also remove dioxins. Reduction of chlorinated compounds fed to the incinerator is not likely to make any significant difference. Good turbulence with elimination of cold spots in the firebox will ensure initial thermal destruction. Dioxins are synthesized on fly ash particles at temperatures between 200 and 400° C. Rapid temperature reduction across this range by water injection will greatly reduce dioxin levels. Catalytic inhibitors can also be used. Since dioxin is adsorbed on fly ash, efficient scrubbing is essential for high removal efficiency. Sorption on active carbon beds is also being evaluated.

Factors Affecting the Incidence of Blood Spots and Their Detection in Hen’s Eggs

INTRODUCTIONBLOOD spots in chicken eggs represent a serious loss to the poultry industry. The reduction or elimination of blood spots presents a complex problem involving genetic, nutritional and environmental factors. Blood spots are one of the most serious obstacles to the marketing of high quality eggs. Loss is due not only to eggs candled out in grading but also to possible decreased consumer demand because of the effect on the consumer of blood spots overlooked in grading.The importance of blood spots as a factor in consumer demand was brought out by Stadelman (1950). Results of a survey showed that 7 percent of all consumer complaints about egg quality concerned blood and meat spots. Since the study was on a graded egg basis, these would be mainly spots overlooked in candling.Most of the previously reported work on this problem has been by use of the candle for identifying .

Improvements in motion picture laboratory apparatus

A number of miscellaneous improvements in laboratory apparatus are described, which have for their object the elimination of spots, scratches, and unevenness of density in processed motion picture film. Modifications in developing room equipment include a vacuum cleaner for removing sludge from developers, a cooling coil for adjusting developer temperature, a new type of rack guide for a developer tank, a compact rack light lock, a waterproof and corrosion-resisting portable darkroom lamp, and some auxiliaries for the prevention of spots and contamination on film. — Improvements in printing room equipment include the addition of a flywheel to a continuous printer to eliminate unevenness in density due to variation in the motion of the film during exposure. Also, a light change has been equipped to control either of two lamps of different wattage giving in each case exposure values which have precisely equal relationships. — Some changes have been made in rewinding equipment which include the addition of a weighted roller to make more firmly wound rolls and a large portable winding core. The design of a standard disk rewind has been changed to facilitate removal of the wound roll. — A film storage cabinet has been designed for laboratory use which gives an increased degree of protection from fire and water, at the same time assisting in the convenient and orderly arrangement of the film.