Physical and frictional properties of non-treated and steam exploded barley, canola, oat and wheat straw grinds

During storage and handling, accurate knowledge of the physical and frictional behaviors of biomass grinds is essential for the efficient design of equipment. Therefore, experiments were performed on non-treated and steam exploded barley, canola, oat and wheat straw grinds to determine their coefficient of internal friction and cohesion at three hammer mill screen sizes of 6.4, 3.2 and 1.6 mm, three normal stress values of 9.8, 19.6 and 39.2 kPa at 10% moisture content (wb). At any specific hammer mill screen size, the geometric mean particle size and bulk density of non-treated straw was significantly larger than steam exploded straw. The bulk density of ground straw significantly increased with a decrease in hammer mill screen sizes. The steam exploded straw grinds resulted in higher coefficient of internal friction compared to non-treated straw grinds primarily because of lower bulk densities. The coefficient of friction for non-treated barley, canola, oat and wheat straw were in the range of 0.505 to 0.584, 0.661 to 0.665, 0.498 to 0.590, and 0.532 to 0.591, respectively. Similarly, the coefficient of friction for steam exploded barley, canola, oat and wheat straw were in the range of 0.562 to 0.738, 0.708 to 0.841, 0.660 to 0.860, and 0.616 to 1.036, respectively, which were higher than non-treated straw of the kind. Power, logarithmic or exponential equations were developed to predict the coefficient of internal friction and cohesion with respect to average geometric mean particle sizes for non-treated and steam explode barley, canola, oat and wheat straw grinds.     

An analytical method for comparing natural diversity to DSMcontrolled diversity

The purpose of this paper is to report an analytical method of comparing natural diversity with controlled diversity, and to show the results of comparing the peak load resulting from natural diversity in a set of air conditioning units to the peak load that can be achieved with DSM control of the same set of air conditioners. In this study it is assumed that the energy use by the air conditioners is the same in both cases. Under this assumption, an analytical model for finding the probabilities of all the possible peak loads is developed and illustrated in case studies     

Review of expert systems in bulk power system planning andoperation

Advantages and disadvantages of expert systems are discussed. An overview of expert system applications being developed or considered high potential is given     

Seismic stability of embankments with different densities and upstream conditions related to the water level

Modeling an embankment by subjecting it to different upstream conditions in a centrifuge is challenging. However, the response of an embankment to shaking under different upstream conditions needs to be studied to ensure that the necessary precautions are taken during its construction and maintenance. Herein, the influence of different upstream conditions and embankment densities are investigated. The pore water pressure values at different locations in an embankment were recorded during seepage and under induced shaking. Accelerometers recorded the response of the embankment to shaking, and a linear variable differential transformer (LVDT) measured the settlement at the top of the embankment as a result of the shaking. An image analysis was used to trace the resulting deformation of the embankment due to the shaking. The results indicate that the upstream conditions of the embankment determine the failure mechanism of the embankment in cases of lower density. In addition, the distribution of the water content within the embankment was found to have a greater influence on its response to shaking than the water level height on its upstream side.     

Rheological properties of ice cream mixes and frozen ice creams containing fat and fat replacers

Ice cream mixes and frozen ice creams at milk fat levels of 12%, 8%, 6%, 6% plus a protein-based fat replacer, and 6% plus a carbohydrate-based fat replacer were evaluated for viscoelastic properties by dynamic testing with sinusoidal oscillatory tests at various frequencies. The storage modulus (G'), loss modulus (G"), and tan delta (G"/G') were calculated for all the treatments to determine changes in the viscous and elastic properties of the mixes and frozen ice creams due to fat content. In ice cream mixes, G' and G" exhibited a strong frequency dependence. The G" was higher than G' throughout the frequency range (1 to 8 Hz) examined, without any crossover, except for the 12% mix. Elastic properties of the ice cream mixes decreased as fat content decreased. Tan delta values indicated that fat replacers did not enhance the elastic properties of the ice cream mixes. In all frozen ice creams, G' and G" again showed a frequency dependence throughout the range tested (0.5 to 10 Hz). The amount of fat in ice creams and the degree of fat destabilization affected the elasticity in the frozen product. Even though the ice creams did not have significant elastic properties, when compared as a group the samples with higher fat content had higher elastic properties. The addition of protein-based and carbohydrate-based fat replacers did not enhance the elastic properties of the ice creams but did increase the viscous properties.     

MECHANISMS OF ICE CRYSTALLIZATION AND RECRYSTALLIZATION IN ICE CREAM: A REVIEW

This review article focuses on the mechanisms of ice crystallization and recrystallization and factors that influence them in ice creams. Ice crystallization is an important factor that determines ice cream's final quality. The smaller the ice crystal size is in the final product, the better the quality is. Large ice crystals cause a coarse, grainy, and icy texture in ice cream. The initial ice crystals are formed in the freezer barrel and then grow in size during hardening and storage. Recrystallization during storage is influenced by various factors, including total solids, initial freezing temperature, unfrozen water, stabilizer type, sweetener type, and storage temperature. The roles of these factors, especially stabilizers, are discussed.     

Thyristor controlled series compensation application study-controlinteraction considerations

A study of the potential for control interaction between a proposed thyristor controlled series compensation (TCSC) and an existing static VAr compensator (SVC) is presented. The results indicate that a control interaction exists between the voltage-input power swing damping control (PSDC) of the TCSC, the series compensated AC system resonances, and the SVC controls. The addition of recommended filtering and synthesized angle-input PSDC showed improved performance     

Estimating the variance of production cost using a stochastic loadmodel

The purpose of this paper is to provide a realistic load variation model to be used in short-term (one to three years) planning studies. A stochastic model is proposed, and this model is used to quantify the variation of the estimated production cost that is directly affected by the load uncertainty. The paper presents a method of estimating the variation of production cost. This is the first paper to use a Gauss-Markov stochastic model of load with a chronological production simulation model. This load model captures the stochastic load variation behavior and the correlation between weekly peak demand and weekly energy. A weekly Gauss-Markov sampling scheme is incorporated in the proposed approach to model load variation. This stochastic load model is used to generate sample chronological load profiles that represent the annual load variation in weekly detail. These load profiles are then used in annual Monte Carlo production simulation. Case studies illustrate the implementation of this stochastic load variation modeling. These case studies illustrate that load uncertainty has a significantly larger effect on cost uncertainty than does uncertainty in unit availability