CONTROL OF FUGITIVE DUST BY WINDBREAKS

Fugitive dust generated by industrial haul roads can be reduced by windbreaks placed upwind or downwind of the road. For an elementary wind profile downwind of a windbreak, the fractional efficiency has been predicted as a function of downwind distance, wind speed and windbreak height and porosity. An analytical model and computer algorithm are proposed to enable engineers to predict the fractional efficiency for any source and wind profile of their choosing.     

A FAST ALGORITHM FOR OPTIMAL HYDROTHERMAL SCHEDULING WITH CASCADED AND INDEPENDENT HYDRO PLANTS

ABSTRACT

This paper presents a fast algorithm for solving the short-term hydrothermal scheduling problem in a power system consisting of cascaded plants with time delay and independent hydro plants. The operational planning of such problem is concerned with the determination of scheduling for hydro as well as thermal plants to meet the daily system demand with the objective of minimizing the total fuel cost of the thermal plants over the day subject to the relevant operating constraints associated with the thermal and hydro plants.

The algorithm employs a fast and simple alternating solution approach for hydrothermal scheduling in which the hydro subproblem is solved using the method of local variation while the associated thermal subproblem is solved through a judicious combination of Successive Linear Programming (SLP) method and Participation Factor method. Many computational features are incorporated in the solution algorithm exploiting the inherent characteristic of the complex hydrothermal scheduling problem.     

Prolactin gene polymorphism in Nili‐Ravi buffaloes in relation to Sahiwal and Achai Cattle

In this study, prolactin gene polymorphism was investigated in Nili‐ Ravi buffaloes, Sahiwal and Achai cattle breeds, 100 per group, using polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) technique. Only genotype GG was observed in the case of Nili‐Ravi buffaloes. In Sahiwal and Achai cattle, three genotypes were found, AA, AG and GG: the frequency of these genotypes were 72%, 18% and 10% in Sahiwal cattle and 44%, 34% and 22% in Achai cattle, respectively. The frequency of genotype AA was found to be higher in both cattle breeds. Results of chi‐square test at P < 0.05 revealed that animals of Achai cattle were in Hardy–Weinberg equilibrium, whereas Sahiwal cattle were found to be deviating.     

POSTHARVEST SENSORY AND PHYSIOCHEMICAL ATTRIBUTES OF PROCESSING AND NONPROCESSING TOMATO CULTIVARS

Fruits of processing and nonprocessing tomato cultivars harvested at the “breaker” stage of maturity were evaluated for changes in physical, chemical and sensory quality characteristics during storage at 20C and 30C after 7, 14 and 21 days. Percentage marketable fruits after 21 days at 20C and 30C were 61.9% and 56.6% for processing cultivars and 65.9% and 50.9% for nonprocessing cultivars. Fruits of the processing cultivars ripened earlier, remained firmer and were less prone to physical injuries than fruits of nonprocessing cultivars. Nonprocessing fruits had a higher mean fruit weight of 17.0 g, fruit diameter of 1.10 mm and locule number of 13 compared with fruits of the processing cultivars. Nonprocessing fruit cultivars had higher sugar/acid ratios and vitamin C contents as well as lower pH and total titratable acidity than processing fruit cultivars. Accordingly, nonprocessing cultivars on the whole, but specifically Walters, Floradel, Carnival, Calypso, Star Pak, Floradade and Early Set were most suitable as fresh-market fruits. Excellent processing quality attributes were obtained for Donore, Peto 94C, Rio Grande and Advantage. Among processing cultivars Caraibe, Cascade, Dorado and Neema 1401 gave good dual purpose fruits.     

CONSUMER ATTITUDES, PREFERENCES AND SHOPPING BEHAVIOR TOWARD HOT PEPPERS IMPORTED FROM TRINIDAD AND TOBAGO

A survey consisting of 108 completed interviews was conducted in two locations in Toronto, Canada, to identify and describe Canadian consumer views at different retail outlets concerning quality, services offered, buying habits and preferences of hot peppers imported from Trinidad and Tobago. At both locations, more consumers preferred to buy hot peppers at supermarkets compared with roadside or farmers’ markets, respectively. Convenience, freshness and sorted and graded produce combined with lower postharvest losses experienced were major factors influencing the decision to shop at supermarket outlets. However, consumers at all retail outlets ranked pungency as the most important quality factor followed by flavor, shelf-life and color. Awareness among growers and exporters at the supply end and brokers and retailers at the receiving end of the export marketing system of this commodity could influence consumer demand for these quality characteristics to result in mutual economic benefits.     

Effects of size on mass density and its influence on mechanical and thermal properties of ZrO<Subscript>2</Subscript> nanoparticles in different structures

This study investigates the effect of size on mass density and its subsequent influence on the other physical parameters of zirconia nanoparticles in the structural forms of cubic, tetragonal and monoclinic. The general equations for these calculations are established based on the variation of lattice parameter model and surface internal atoms ratio. The mass density of nanoparticles differs from the bulk value when particle size decreases. At a diameter of 4 nm, the mass density values of zirconia nanoparticles are 3.898, 3.626 and 3.488 g ? cm^?3 compared to 6.25, 6.1 and 5.87 g? cm^?3 for bulk cubic, tetragonal and monoclinic forms, respectively. These results indicate that the variation in mass density is largely due to the differences on their boundaries and the variation in lattice parameters. The calculated results agree well with the available experimental data for the monoclinic form structure of ZrO ₂ nanoparticles. The relationship between mass density and melting temperature; and Debye temperature and cohesive energy are proposed. All these parameters have the same nanosize dependence in this regard.     

Three Centuries of Polycyclic Aromatic Hydrocarbons and Teriterpane Records In Tebrau Strait,Malaysia; Recent Pollution Concern in a Pristine Marine Environment

In the last century, application of fossil fuel as the primary source of energy caused environmental pollution in many countries including Malaysia. Polycyclic Aromatic Hydrocarbons (PAHs) are an important class of petroleum contamination. Two sediment cores were collected from the Tebrau Strait at the southern part of Peninsular Malaysia near the border line to Singapore, where entering into the South China Sea. The samples were sliced in certain intervals, extracted with Dichloromethane in Soxhlet apparatus, cleaned and fractionated in 2-steps column chromatography, and analyzed in Gas Chromatography – Mass Spectrometry. The results showed that PAHs input were started soon after World War II and exponentially increased from 1980 onward by 310 ng/g d. w., in comparison it was negligible and probably nature derived during 18^th and 19^th century. The application of compound-specific ratios and pentacyclic teriterpanes suggested the vicinity of sources that atmospherically transported to the sampling locations. They were originated from combusted oil of Southeast Asian and the Middle East, polluting urban sediment and street dusts prior to final deposition. Biomass burning appeared historically as a predominant minor background pollution of both cores. Remarkably, crankcase oil was not traced in this study while it was reported as a predominant source in Malaysia. This study suggested ocean-going ships and Singapore International Airport as the main sources of petroleum pollution in recent decades since there was insignificant rural development surrounding the studied area.     

A systematic method for eigenstructure assignment and application to response shaping

The simultaneous assignment of eigenvalue and eigenvector in a dynamic system using a constant-gain state-feedback controller is formulated as a static optimization problem. Response shaping by adequately damping the dominant modes or by eliminating the uncontrollable modes is possible in this formulation. Systematic solution through a standard LP routine makes the method attractive for practical implementation. The proposed eigenstructure-assignment algorithm is illustrated through two examples, one of which is the stabilization of a single machine connected to an infinite-bus power system.