Comparative analysis of energy resources

This paper examines the problems encountered by a growing demand for energy consumption and a dwindling reserve of conventional energy sources Development of alternative clean energy sources should be vigorously pursued in order to improve or maintain the quality of life. The search for new energy sources has indicated the need for developing approaches to evaluate feasibility and competitiveness of the alternative sources. Frequently mentioned as alternative energy sources are wind power, water power, tidal power, coal, fission energy with or without breeders, geothermal energy, ocean thermal energy conversion, low temperature solar energy, solar power through photosynthesis and solar electric: generation. Factors considered in comparing these energy sources are given. An illustration based on United States energy consumption rates and available energy resources provide revealing information about future directions in energy production.

Requirements for economic comparative models are discussed and an example is given.     

Extrusion of Pinto Bean High Protein Fraction Pretreated with Papain and Cellulase Enzymes

High protein fraction of pinto bean was pretreated with papain and cellulase enzymes and extruded at a temperature of 120°C. The effect of enzyme type and concentration, moisture and duration of incubation on expansion, texture, color, water absorption and solubility, pH, sugars, nitrogen solubility index and in vitro protein digestibility of the extrudate were investigated. Enzymatic modification had differential effects on nitrogen and carbohydrate components and on some physical and functional preperties of extrudates, depending on type of enzyme and incubation conditions. Results indicated the possibility of controlling protein and fiber hydrolysis at low moisture to obtain a desirable degree of modification to improve extruded products. This method may be used in food applications to obtain new snack type products from beans or their fractions.     

Mechanical wet-milling and subsequent consolidation of ultra-fine Al2O3-（ZrO2＋3%Y2O3） bioceramics by using high-frequency induction heat sintering

Alumina/zirconia composites were synthesized by wet-milling technique and rapid consolidation with high frequency induction heat sintering(HFIHS). The starting materials were a mixture of alumina micro-powder (80%, volume fraction) and 3YSZ nano-powders (20%). The mixtures were optimized for good sintering behaviors and mechanical properties. Nano-crystalline grains are obtained after 24 h milling. The nano-structured powder compacts are then processed to full density at different temperatures by HFIHS. Effects of temperature on the mechanical and microstructure properties were studied. Al2O3-3YSZ composites with higher mechanical properties and small grain size are successfully developed at relatively low temperatures through this technique.     

High Temperature Extrusion Effects on Protein Solubility and Distribution in Navy and Pinto Beans

Osborne protein solubility fractionation and polyacrylamide gel electrophoresis (PAGE) showed changes in protein distribution during high temperature extrusion of pinto and navy bean high starch fraction (HSF). A high degree of protein insolubility was found after extrusion, which resulted in a decrease in solubility of albumin and globulin fractions and an increase in the residue. An extrusion temperature of 110°C had a greater effect on solubility of albumin and globulin fractions of pinto than navy bean. Sodium dodecyl sulfate (SDS)-PAGE showed more changes in subunit patterns of albumin and globulin for pinto than for navy beans at 110°C. Higher temperatures of 135 and 150°C caused greater changes in gel electrophoretic patterns of albumin and globulin fractions of navy beans.     

Functional Properties of Extrudates from High Starch Fractions of Navy and Pinto Beans and Corn Meal Blended with Legume High Protein Fractions

High protein fractions (HPF) of navy and pinto beans were mixed with high starch fraction (HSF) or corn meal and extrusion-cooked. HSF of pintos blended with hull fractions was extruded at 132°C. Expansion index (EI), density, color, water absorption (WAI), water (WSI) and nitrogen solubility (NSI), oil absorption (OAC) and emulsification (OEC) were evaluated. Extruded blends had lower EI and OAC, higher protein density and OEC than extruded corn or HSF. WAI and WSI were variable. EI decreased with increased protein. Scanning electronic microscopy showed protein level had pronounced influence on microstructure, size of air cells and smoothness of cell walls. Hull fraction added to HSF, caused decreases in EI, WAI, WSI while NSI, OAC and OEC were unaffected.     

THE EFFECT OF PHYTATE AND FIBER CONTENT ON COOKING QUALITY IN FABA BEANS

Seventy-six faba bean lines were analyzed for their phytic acid content in the whole seeds and in the cotyledons. The fiber content was also determined in 17 Faba bean lines. The seed weights; % testa weight-of the seeds; and % moisture uptake (water imbibition) after overnight soaking in distilled water or increasing concentrations of EDTA solutions were measured and recorded. The relation between the above mentioned dependent variables and the cooking time for seed softening (min.) in 76 faba bean lines was studied and simple and multiple correlation coefficients were computed with a total of 70 operations. Significant correlation coefficients were found between phytic acid content in the cotyledons, % testae weight of the seeds; moisture uptake after soaking the seeds in distilled water overnight and cooking time for 50% softening (min). The faba bean lines 606/ 303; 606/ 308, 608/ 334, 609/ 350, proved to be of excellent cooking quality, since their cooking time for 50% seed softening did not exceed 10 min.     

Prediction of crack opening stress levels for 1045 quenched and tempered steel under service loading spectra

The opening stresses of a crack emanating from an edge notch in a 1045 quenched and tempered steel specimen were measured under two different Society of Automotive Engineers (SAE) standard service load histories having different average mean stress levels. The two spectra are the Grapple Skidder history (GSH), which has a positive average mean stress, and the Log Skidder history (LSH), which has a zero average mean stress. To capture the behaviour of the crack opening stress in the material, the crack opening stress levels were measured at 900X using an optical video microscope, at frequent intervals for each set of histories scaled to two different maximum stress ranges.A crack growth analysis based on a fracture mechanics approach was used to model the fatigue behaviour of the steel specimens for the given load spectra and stress ranges. Crack growth analysis was based on an effective strain‐based intensity factor, a crack growth rate curve obtained during closure‐free loading cycles and a local notch strain calculation based on Neuber's rule.The crack opening stress (S_op) was modelled and the model was implemented in a fatigue notch model, and the fatigue lives of the specimens under the two different spectra scaled to several maximum stress levels were estimated. The average measured crack opening stresses were between 6 and 12% of the average calculated crack opening stresses. In the interest of simplifying the use of S_op in design, the average S_op was correlated with the frequency of occurrence of the cycle reducing the S_op to the average crack opening stress level. The use of an S_op level corresponding to the cycle causing a reduction in S_op to a level reached once per 10 cycles gave a conservative estimate of average crack opening stress for all the histories.     

Growth and Compositional Changes During the Various Developmental Stages of Some Saudi Arabian Date Cultivars

Compositional changes during fruit maturation were studied in two important date cultivars grown in Saudi Arabia. Physical analyses showed that the fruit weight, length, diameter and weight of seed were highest at the mature color stage. Chemical analyses including moisture, total nitrogen, fat, fiber, ash, tannins, vitamin C, β-carotene, and 10 nutritionally essential minerals showed that all were highest at the early stages of development and decreased during maturation. Reducing sugars were dominant in both cultivars and showed progressive increase during ripening with fructose and glucose as the only detected constituents. Sucrose content reached its maximum in both cultivars at the mature color stage then dropped sharply at the ripe stage. The total sugar content in both cultivars tended to increase all throughout maturation.     

Instrumental and Sensory Evaluation of Textural Properties of Extrudates from Blends of High Starch/High Protein Fractions of Dry Beans

A Wenger X5 single-screw extruder was used to produce bean extrudates from formulations modified by addition of high protein bean fraction or hull. The effect of process temperature was investigated. The higher the process temperature, the lower was the sample stress and the higher the sensory score for crispness. Product processed below 121°C was unacceptable. Crispness was good for samples containing 13–16% protein or 17–21% fiber; outside these ranges the extrudates were too hard. Shear stress increased uniformly with increasing protein or fiber content. A satisfactory correlation was observed between sensory and instrumental test results for texture: the higher the shearing stress, the lower was the sensory score for crispness.     

Chemical Composition and Nutritional Quality of Camel Milk

The chemical composition and nutritional quality of camel milk was studied. Results showed 11.7% total solids, 3.0% protein, 3.6% fat, 0.8% ash, 4.4% lactose, 0.13% acidity and a pH of 6.5. The levels of Na, K, Zn, Fe, Cu, Mn, niacin and vitamin C were higher and thiamin, riboflavin, folacin, vitamin Bt₁₂, pantothenic acid, vitamin A, lysine and tryptophan were relatively lower than those of cow milk. Gas liquid chromatography analysis of milk fat showed a molar percent of 26.7 for palmitic, 25.5 oleic, 11.4 myristic, and 11.0 palmitoleic. In vitro protein digestibility and calculated protein efficiency ratio values were 81.4% and 2.69, respectively, based on 90.0% and 2.50 for ANRC-Casein.