Home About us Contact
|
Home About us Contact | ||
|
|
||
Extraction Rate (extraction + rate)
Selected AbstractsCMR 2005: 1.02: Extraction rate of SPIO by the normal and gadolinium chloride-treated liverCONTRAST MEDIA & MOLECULAR IMAGING, Issue 2 2006S. Hirohashi [source] Comparison of conventional and ultrasound-assisted extraction of carvone and limonene from caraway seedsFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2004Smain Chemat Abstract Extraction experiments with hexane were carried out at atmospheric pressure in Soxhlet, conventional and ultrasound extractions of ,aked caraway seeds, and detailed results are given for two major plant extract components, carvone and limonene. The results indicate that carvone yield and plant extract quality are better in ultrasound extraction compared to those given by conventional methodology. Extraction rates of carvone and limonene reported that ultrasound-assisted extraction was 1.3,2 times more rapid, depending on temperature, than a conventional system, according to the rate constant obtained during the initial 10 minutes of extraction. Moreover, the SEM micrographs provided more evidence for the mechanical effects of ultrasound, mainly appearing on cell walls and shown by the destruction of cells, faulitating the release of their contents, in contrast to conventional maceration or extraction, which involve diffusion of plant extracts across glandular walls and causing cell rupture over longer time periods. Copyright © 2004 John Wiley & Sons, Ltd. [source] Recharge of aquifers by flood events in an arid regionHYDROLOGICAL PROCESSES, Issue 4 2003Isabella Shentsis Abstract The process of aquifer recharge by flood events in an arid region was investigated as applied to the Hazeva Formation (the Karkom graben, the Wadi Paran watershed, Israel). The hydrological model was established as a complex system, with due regard for groundwater and transmission losses of surface runoff. It was based on a previously outlined hydrogeological model of the Karkom graben and a model of transmission losses in arid watercourses under conditions of data deficiency. Proceeding from calculation of groundwater balances, the contribution of surface runoff as a decisive balance component was confirmed. The main characteristics of aquifer regimes, such as changes in storage volume and groundwater level, as well as lateral flow, were all found to be dependent upon the net extraction rate, i.e. pumpage discounting replenishment by flood events. Analysis and physical interpretation of model parameters enabled assessment of the influence of groundwater extraction on aquifer recharge. This became apparent as increasing absorption capacity and recharge availability of the aquifer as a result of the groundwater abstraction. Copyright © 2002 John Wiley & Sons, Ltd. [source] Exergetic performance assessment of a ground-source heat pump drying systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 8 2007Ebru Hancioglu Kuzgunkaya Abstract In evaluating the efficiency of heat pump (HP) systems, the most commonly used measure is the energy (or first law) efficiency, which is modified to a coefficient of performance (COP) for HP systems. However, for indicating the possibilities for thermodynamic improvement, energy analysis is inadequate and exergy analysis is needed. This study presents an exergetic assessment of a ground-source (or geothermal) HP (GSHP) drying system. This system was designed, constructed and tested in the Solar Energy Institute of Ege University, Izmir, Turkey. The exergy destructions in each of the components of the overall system are determined for average values of experimentally measured parameters. Exergy efficiencies of the system components are determined to assess their performances and to elucidate potentials for improvement. COP values for the GSHP unit and overall GSHP drying system are found to range between 1.63,2.88 and 1.45,2.65, respectively, while corresponding exergy efficiency values on a product/fuel basis are found to be 21.1 and 15.5% at a dead state temperature of 27°C, respectively. Specific moisture extraction rate (SMER) on the system basis is obtained to be 0.122 kg kW,1 h,1. For drying systems, the so-called specific moisture exergetic rate (SMExR), which is defined as the ratio of the moisture removed in kg to the exergy input in kW h, is also proposed by the authors. The SMExR of the whole GSHP drying system is found to be 5.11 kg kW,1 h,1. Copyright © 2006 John Wiley & Sons, Ltd. [source] Experimental investigation of the performance of a solar-assisted ground-source heat pump system for greenhouse heatingINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2005Onder Ozgener Abstract The main objective of the present study is to investigate the performance characteristics of a solar-assisted ground-source heat pump system (SAGSHPS) for greenhouse heating with a 50 m vertical 1¼ in nominal diameter U-bend ground heat exchanger. This system was designed and installed in the Solar Energy Institute, Ege University, Izmir (568 degree days cooling, base: 22°C, 1226 degree days heating, base: 18°C), Turkey. Based upon the measurements made in the heating mode, the heat extraction rate from the soil is found to be, on average, 54.08 Wm,1 of bore depth, while the required borehole length in meter per kW of heating capacity is obtained as 12.57. The entering water temperature to the unit ranges from 8.2 to 16.2°C, with an average value of 9.1°C. The greenhouse air is at a maximum day temperature of 25°C and night temperature of 14°C with a relative humidity of 40%. The heating coefficient of performance of the heat pump (COPHP) is about 2.13 at the end of a cloudy day, while it is about 2.84 at the end of sunny day and fluctuates between these values in other times. The COP values for the whole system are also obtained to be 5,15% lower than COPHP. Copyright © 2004 John Wiley & Sons, Ltd. [source] Indigenous children and receipt of hospital dental care in AustraliaINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 5 2006L. M. JAMIESON Summary., Objective., The aim of this study was to investigate dental procedures received under hospital general anaesthetic by indigenous and non-indigenous Australian children in 2002,2003. Methods., Separation data from 1297 public and private hospitals were obtained from the Australian Institute of Health and Welfare National Hospital Morbidity Database for 2002,2003. The dependant variable was the admission rate of children receiving four categories of dental care (i.e. extraction, pulpal, restoration or other). The explanatory variables included sex, age group, indigenous status and location (i.e. major city, regional or remote). Rates were calculated using estimated resident population counts. Results., The sample included 24 874 children aged from 2 to 14 years. Some 4·3% were indigenous (n = 1062). Admission rates for indigenous and non-indigenous children were similar, with indigenous males having 1·2 times the admission rate of indigenous females (P < 0·05). Indigenous children aged < 5 years had 1·4 times the admission rate of similarly aged non-indigenous children (P < 0·001) and 5·0 times the admission rate of 10,14-year-old indigenous children (P < 0·001). Remote-living indigenous children had 1·5 times the admission rate of their counterparts in major cities or regional areas (P < 0·001), and 1·4 times the admission rate of remote-living non-indigenous children (P < 0·01). The extraction rate of indigenous males was 1·3 times that of non-indigenous males (P < 0·01), and 1·2 times that of indigenous females (P < 0·05). Pre-school indigenous children had 2·2 times the extraction rate of similarly aged non-indigenous children (P < 0·001), and 5·3 times that of indigenous 10,14-year-olds (P < 0·001). The extraction rate of remotely located indigenous children was 1·5 times that of indigenous children in major cities (P < 0·01), and 1·8 times that of remote-living non-indigenous children (P < 0·001). Conclusions., In certain strata , particularly males, the very young and those in remote locations , indigenous children experienced higher rates of extractions than non-indigenous children when undergoing care in a hospital dental general anaesthetic setting. [source] Influence of prey size on predation success by Zelus longipes L. (Het., Reduviidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 2-3 2002R. Cogni The effects of prey size on the predatory responses of the reduviid Zelus longipes were studied through laboratory tests using larvae of the noctuid moth Spodoptera frugiperda as preys. In tests with one caterpillar, larvae of three different weight classes were offered individually to the predator. The prey weight was positively correlated with relative weight gain by the predator, mean feeding time and discarded biomass, but not with the relative extraction rate (defined as the relative weight gain by the predator by feeding time). The different sizes of caterpillars were attacked with the same frequency, but the successful attacks were more frequent in small larvae. The median mass of successfully attacked larvae was also less than that of unsuccessfully attacked. In tests with three caterpillars, larvae of three weight classes were offered at the same time; small caterpillars were more often attacked and killed than the medium and large ones. The results showed that even if larger preys resulted in more energy intake, when the choice is possible, smaller caterpillars were more likely to be attacked than medium and large. This is probably related to the fact that successful attacks were more frequent in small larvae, and also reduced the risk of injury to the predator. [source] Supercritical CO2 extraction of accumulated capsidiol from biotic elicitor-activated Capsicum annuum L fruit tissuesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2005ur Salg Abstract This work investigates the supercritical CO2 extraction of capsidiol from pepper fruit tissues activated with Alternaria alternate (Fr) Keissler suspension culture as a biotic elicitor. Capsidiol production in the fruit tissue was markedly increased by the treatment with a biotic elicitor and reached its maximum level after 4 days of elicitation. The effects of separation parameters such as temperature, pressure, supercritical solvent flow rate, particle diameter and also initial capsidiol concentration were investigated on solubility, initial extraction rate and extraction yield. The optimal extraction conditions were obtained at the temperature of 40 °C, the pressure of 400 bar, the supercritical CO2 flow rate of 2 cm3 min,1, and the average particle diameter of 116 µm. The results showed that the ratio of the supercritical CO2 extraction yield to the organic solvent extraction yield was changed from 84 to 97 wt-% depending on the initial capsidiol concentration. Copyright © 2004 Society of Chemical Industry [source] EFFECT OF PENTOSANASE ON DOUGH AND BREAD PROPERTIES PRODUCED BY DIFFERENT TYPES OF FLOURSJOURNAL OF FOOD QUALITY, Issue 2 2008ÖZKAN KOYUNCU ABSTRACT The effects of pentosanase at different doses (20, 60 and 100 ppm) on physical dough properties and bread quality were studied using three types of wheat flours. Flour A was a regular bread flour, flour B had a high hardness ratio and protein content, and flour C was prepared from the same blend of flour A but had a high extraction ratio. Regarding farinograph data, water absorption values of the high extraction (86%) flour C and high hardness (65%) blend flour B increased with introduction of pentosanase. Extensibility values of the flours increased moderately with pentosanase addition, while resistance and energy values decreased. The volume of breads made with flours C and B decreased upon addition of pentosanase. But loaf volume of breads prepared with regular bread flour A with 50% hardness and 76% extraction rate increased with high levels of pentosanase addition. In conclusion, flour A as a regular bread flour gave satisfactory results with pentosanase supplementations, whereas the harder-blend (65%) and higher-extraction-rate (85%) flours from the same cultivars did not. PRACTICAL APPLICATIONS Pentosanase addition was more effective on soluble pentosans than on insoluble ones. Because of these effects, it enhanced the bread-making properties of regular flour more effectively than those of the high-extraction and harder-blend flours of the same cultivars. [source] Air Current Segregation of Alumina PowderPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 2 2007Stefan Zigan Abstract This paper outlines the industrial problem of air current segregation in alumina storage silos which occurs with the handling of the feedstock alumina in aluminium plants and investigates the parameters that affect the severity of the segregation. Bates [1] stated that the feeding rate influences segregation which we can confirm with own experimental findings. Higher powder flow rates tend to reduce air current segregation. Cooper et al. [2] pointed out that the air extraction rate affects the content of fine particles (dust) in the circulating air currents and we confirm his finding. The importance of the effect of different feeding rates on air current segregation was discovered in a two dimensional apparatus. The investigation of the influence of air extraction rate was realised in a cylindrical silo. Both experiments show a strong relationship between the strength of the particle-air flow in the silo and air current segregation. It is found that an increase of the powder feeding rate or the air extraction rate reduces air current segregation in the experimental equipment. The aim of our experiments was to find all significant parameters and to apply dimensional analysis to develop a method which scales the findings from small scale experiments to large industrial alumina silos. Five dimensionless groups were obtained, which is unwieldy. To reduce the number of dimensionless groups, physical properties were lumped into the terminal velocity. This simplified approach gives three dimensionless groups. Experiments in a water model and an air model justify more research using this simplified scaling method. [source] Effect of Modified Enzymatic Catalysis on the Extraction of Diosgenin from Dioscorea zingiberensis C.,H.CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2007Wright Abstract Multi-enzymatic catalysis combined with acid hydrolysis is studied in order to enhance the efficiency of the enzymatic catalysis and reduce the mass transfer resistance from starch and cellulose in the extraction of diosgenin from Dioscorea zingiberensis C.,H. Wright. The cellulase is modified by polyethylene to increase its optimal reaction temperature and pH value. The modified cellulase shows better thermostability and resistance to alkali. The modified cellulase, , -amylase and , -glycosidase are used to construct the multi-enzyme and multi-enzyme catalysis is used as a pretreatment process. Compared to primary industrial techniques including acid hydrolysis, spontaneous fermentation and enzymatic catalysis, conventional techniques are optimized by using multi-enzymatic catalysis together with acid hydrolysis because of the higher reaction efficiency and lower levels of manipulation required. The purity of the product is more than 96,% with this technique, and the melting point is 205,207,°C. The diosgenin yield rate and the extraction rate reached are 2.43,% and 98,%, respectively. IR and 1H NMR spectroscopy were used to confirm the structure of the product. [source] Soil water dynamics along a tree diversity gradient in a deciduous forest in Central GermanyECOHYDROLOGY, Issue 3 2010Inga Krämer Abstract This study aimed to investigate whether soil water dynamics differ along a tree species diversity gradient. The 12 study plots in the Hainich National Park, Germany, were composed of up to 11 tree species. Fagus sylvatica formed the monospecific plots. Mixed forest plots consisted of a variable admixture of other broad-leaved deciduous tree species such as Tilia spp., Fraxinus excelsior, Carpinus betulus, and Acer pseudoplatanus. Volumetric soil water content and soil water potential were measured for about two and a half years. Overall patterns of soil water dynamics were similar in all study plots. However, during a desiccation period in summer 2006, significant correlations between soil water in the upper soil and tree species diversity of the 12 study plots were observed. At the beginning of this period, soil water was extracted at higher rates in the species-rich plots than in the beech-dominated plots. However, later during the desiccation period, when atmospheric evaporative demand was higher, only the beech-dominated stands were able to increase soil water extraction. In plots of high tree species diversity, soil water reserves were already low and soil water extraction reduced. Possible explanations for high water extraction rates in mixed species plots at the beginning of the desiccation period include species-specific characteristics such as high maximum water use rate of some species, enhanced exploitation of soil water resources in mixed stands (complementarity effect), and additional water use of the herb layer, which increased along the tree species diversity gradient. Copyright © 2010 John Wiley & Sons, Ltd. [source] ENZYMATIC HYDROLYSIS OF SOYBEAN FOR SOLVENT AND MECHANICAL OIL EXTRACTIONJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2000PRAVEEN C. BARGALE ABSTRACT Due to inefficient extractability of its low oil content, soybeans are often bypassed in village-scale processing. Soygrits, flakes, and expanded collets were hydrolyzed by proteases, cellulases, and pectinases before oil extraction by solvent and static mechanical pressure. Driselase with multi-enzyme activity and two proteases improved solvent extraction rates but only Driselase enhanced mechanical pressing. Up to 58% of seed oil was pressed from enzyme-hydrolyzed flakes but 88% was pressed from Driselase-treated collets. Either pretreatment is a feasible adjunct to mechanical pressing in small batch operations. [source] Extraction Using Moderate Electric FieldsJOURNAL OF FOOD SCIENCE, Issue 1 2004I. SENSOY ABSTRACT: During moderate electric field (MEF) processing, a voltage applied across a food material may affect the permeability of cell membranes. It is known that high electric fields can cause either reversible or irreversible rupture of cell membranes. In this research, the effect of MEF processing on permeability was studied. Effects of frequency and electric field strength were investigated. Cellular structure was investigated by transmission electron microscopy (TEM). Fermented black tea leaves and fresh or dry mint leaves were placed in tea bags or cut in 1 cm2 squares, depending on the experiment, and immersed in an aqueous fluid medium. Control samples were heated on a hot plate. MEF treatments were conducted by applying a voltage across electrodes immersed in opposite sides of the beaker. Control and MEF-treated fresh mint leaf samples heated to 50°C were analyzed by TEM. MEF processing significantly increased the extraction yield for fresh mint leaves because of additional electric field effects during heating. Dried mint leaves and fermented black tea leaves were not affected by the treatment type. Low frequency resulted in higher extraction rates for fresh mint leaves. The electric field strength study showed that electrical breakdown is achieved even at low electric field strengths. MEF treatment shows potential to be used as an alternative to conventional heating for extraction from cellular materials. [source] Protein and the demand for hard wheats,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 2 2009William W. Wilson Wheat protein is one of the most important specifications used in domestic and import purchase contracts and is used partly as a proxy for functional quality. The purpose of this article is to analyse the demand for wheat delineated by protein class. A choice-based econometric model is specified and estimated using a novel dataset of pooled wheat shipments to individual importing countries. Buyers are importing countries that make purchase decisions among different protein levels. The model frames the choice in terms of attributes of the choice and of the importing countries. Results indicate that there have been shifts over time, and purchase probabilities are highly price elastic and vary across importing regions. Functional characteristics including wet gluten content and extraction rates have significant impacts on purchase probabilities. These results have implications for breeders as it clearly illustrates the role of protein and functional characteristics on demand. The results also have implications for analysts modelling wheat trade in that there are many factors impacting market segments that would not be captured in conventional demand specifications. [source] | ||||||||||||||||