Enhanced in situ ethanolysis of Jatropha curcas L. in the presence of cetyltrimethylammonium bromide as a phase transfer catalyst

Limited solubility of alcohols in vegetable oils hinders transesterification reaction process. Phase transfer catalysis can be of great advantage to enhance the reaction rates. Addition of cetyltrimethylammonium bromide as a phase transfer catalyst on in situ transesterification of Jatropha curcas L. with alkaline ethanol was investigated. Use of cetyltrimethylammonium bromide increased the yield of fatty acid ethyl esters. Optimum operating conditions were experimentally established. Yield of fatty acid ethyl esters increased from 89.2 wt% to 99.5 wt% with reduced requirement of ethanol by 16.7 v%, sodium hydroxide catalyst by 33.3 wt%, at a lower temperature of 30 °C and reduced mixing speed in shorter reaction time. The quality of fatty acid ethyl esters fuel conforms to the standards of ASTM D6751 and EN-14214.     

Employment,income, migration and public services: A simultaneous spatial panel data model of regional growth*

We estimate a regional spatial panel simultaneous‐equations growth model, using a five‐step new estimation strategy that generalizes an approach outlined in Kelejian and Prucha. The study region consists of the 418 Appalachian counties 1980?2000. Estimates show feedback simultaneities among the endogenous variables, conditional convergence with respect to the respective endogenous variables, and spatial autoregressive lag and spatial cross‐regressive lag effects with respect to the endogenous variables. A key policy conclusion is that sector‐specific programs should be integrated and harmonized and that regionally differentiated development policies may yield greater returns than treating all locations the same. Estimamos un modelo de crecimiento de panel espacial regional por ecuaciones simultaneas, utilizando una nueva estrategia de estimación de cinco pasos que generaliza una enfoque descrito en Kelejian y Prucha. La región de estudio comprende los 418 condados Apalaches 1980‐2000. Las estimaciones muestran simultaneidades de retroalimentación entre las variables endógenas, convergencia condicional con respecto a las variables endógenas respectivas, y un retardo espacial autorregresivo y efectos de retardo regresivos cruzados espaciales con respecto a las variables endógenas. Una conclusión clave sobre políticas es que los programas sectoriales específicos deberían estar integrados y armonizados, y que las políticas de desarrollo diferenciadas regionalmente podrían producir mejores retornos que si se tratasen todas las localizaciones del mismo modo.      

Spontaneously induced atom–radiation entanglement in an ensemble of trapped two-level atoms

Analysis of the effects of the spontaneously induced correlation on atom–radiation entanglement in an ensemble of two-level atoms initially prepared in the upper energy level and then trapped in a cavity containing a source of a squeezed radiation employing the method of evaluating the coherent-state propagator is presented. It is found that the cavity radiation exhibits squeezing which is directly attributed to the squeezed radiation initially present in the cavity. The intensity of the cavity radiation increases with the squeeze parameter and interaction time. It is also shown that a substantial degree of entanglement between the atomic state and radiation mode exits at a particular time which depends on the coupling constant and squeeze parameter. It is understood that although the squeezed radiation is directly accountable for the cavity squeezing, it significantly destroys the atom–radiation entanglement induced by the correlation between spontaneously emitted radiation and the atoms.     

County-level determinants of local public services in Appalachia: a multivariate spatial autoregressive model approach

We develop a multivariate spatial autoregressive model of local public expenditure determination based on the maximization of a strictly quasi-concave community utility function. The existence of spatial interdependence is tested for both the spatial error and spatial lag model. The full model is estimated by efficient GMM following Kelejian and Prucha (J Real Estate Finan Econ 17(1):99?C121, 1998). The results indicate significant spillover effects among local governments with respect to spending on public services. The OLS estimates of the conventional (non-spatial) model and the corresponding maximum likelihood estimates of the spatial lag and the spatial error models are presented for comparison purposes. The GMM estimates are found to be more efficient.     

Effect of body fatness and glucogenic supplement on lipid and protein mobilization and plasma leptin in dairy cows

Twenty-four multiparous Ayrshire cows were used in an experiment to test the effect of body fatness and glucogenic supplement, fed during the transition period, on lipid and protein mobilization and plasma hormone concentrations. Eight weeks before their expected calving date, the cows were divided into blocks of 4. Two cows with the highest body condition score within each block were then allocated to a test (T) group and the other 2 cows to a control (C) group. To scale up the differences between fatter and thinner cows, the estimated energy allowance was 40% higher in group T than in group C between d 56 and 21 prepartum. For the final 3 wk before calving, all the cows were fed according to energy recommendations for pregnant cows. Within C and T groups and blocks, cows were randomly assigned into groups with (G1) or without (G0) glucogenic supplement. Division to G0 and G1 groups was made 2 wk before the expected calving and continued for 56 d postpartum. After calving, all the cows received grass silage ad libitum and a common daily concentrate allowance. No significant differences were detected in feed intake and milk yield between C and T. The T groups showed an earlier rise of nonesterified fatty acids as calving approached and had higher plasma nonesterified fatty acids during the final week of pregnancy and lactation wk 1 to 3. At the same time, adipose tissue samples from fatter cows tended to show higher in vitro lipolytic responses to added norepinephrine, as monitored by glycerol release. Protein mobilization was elevated during the final week of pregnancy and tended to be more increased in fatter cows. Glucogenic supplement did not decrease lipid or protein mobilization. Fatter cows had higher plasma leptin concentration prepartum, showed a more pronounced decrease in leptin concentration near calving, and had higher plasma leptin concentration after calving. In conclusion, fatter cows initiated more extensive mobilization of body fat before calving and this continued during the first lactation weeks. Plasma leptin concentration in early-lactation cows was associated with body fatness and not with estimated energy balance.     

Safer-sex education for persons with mental illness

1. Safer-sex education is crucial for controlling the spread of HIV and this education is within the realm of nursing practice. 2. Safer-sex education for persons with mental illness must include repetitive, interactive education capitalizing on verbal, visual, written, tactile, and motor skill teaching methods to compensate for learning disabilities that have been identified in this population. 3. In this study, individual rather than a group teaching approach to the sensitive subject of safer-sex provided the most learning. The study subjects did not exhibit overt sexual behavior, increased sexual acting out, regression, or overstimulation when safer-sex education was presented.     

Prediction models for density and viscosity of biodiesel and their effects on fuel supply system in CI engines

Biodiesel is a promising non-toxic and biodegradable alternative fuel used in the transport sector. Nevertheless, the higher viscosity and density of biodiesel poses some acute problems when it is used it in unmodified engine. Taking this into consideration, this study has been focused towards two objectives. The first objective is to identify the effect of temperature on density and viscosity for a variety of biodiesels and also to develop a correlation between density and viscosity for these biodiesels. The second objective is to investigate and quantify the effects of density and viscosity of the biodiesels and their blends on various components of the engine fuel supply system such as fuel pump, fuel filters and fuel injector. To achieve first objective density and viscosity of rapeseed oil biodiesel, corn oil biodiesel and waste oil biodiesel blends (0B, 5B, 10B, 20B, 50B, 75B, and 100B) were tested at different temperatures using EN ISO 3675:1998 and EN ISO 3104:1996 standards. For both density and viscosity new correlations were developed and compared with published literature. A new correlation between biodiesel density and biodiesel viscosity was also developed. The second objective was achieved by using analytical models showing the effects of density and viscosity on the performance of fuel supply system. These effects were quantified over a wide range of engine operating conditions. It can be seen that the higher density and viscosity of biodiesel have a significant impact on the performance of fuel pumps and fuel filters as well as on air-fuel mixing behaviour of compression ignition (CI) engine.     

交变磁场对换热器阻垢效果的研究

采用自行研制的电子除垢仪所产生的交变磁场对换热器进行阻垢试验,考察了磁感应强度、水的硬度、温度、流速及压力对结垢量的影响.结果表明,不同进水硬度下,管壁的结垢量均随磁感应强度的增加而减少;使用电子除垢仪时的管壁结垢量较未使用电子除垢仪时显著减少;使用电子除垢仪时,管壁的结垢量随溶液硬度、温度的增加而呈缓慢上升趋势,流速和压力对结垢量几乎无影响;不使用电子除垢仪时,管壁的结垢量随溶液硬度、温度、流速的增加而迅速上升,但压力对结垢量基本无影响.     

Effect of decoherence on the radiative and squeezing properties in a coherently driven trapped two-level atom

Analysis of the effects of decoherence on the radiative and squeezing properties of a coherently driven two-level atom trapped in a resonant cavity applying the corresponding master equation is presented. The atomic dynamics as well as the squeezing and statistical properties of the emitted radiation are investigated. It is found that the atom stays in the lower energy level more often at steady state irrespective of the strength of the coherent radiation and thermal fluctuations entering the cavity. Moreover, a strong external coherent radiation results in the splitting of the line of the emission spectrum, whereas the decoherence broadens the width and significantly decreases the height. It is also found that the emitted radiation exhibits photon anti-bunching, super-Poissonian photon statistics and squeezing, despite the presence of the decoherence which is expected to destroy the quantum features.