Drying of post-harvest rough rice with silica gel: A preliminary investigation

Rice drying operations can encounter problems of over drying and losses in head rice yield (HRY) through the formation of fissures. Typical rice drying methods also utilize large volumes of expensive fossil fuels to dry the kernels. Drying of rice with a solid desiccant such as silica gel has several potential advantages that avoid some of these problems. Two cultivars of long-grain rough rice, ‘Cheniere’ and ‘Wells’ with harvest moisture contents of 17.8% and 22.0%, respectively, were dried over a 48-h period with various ratios of rough rice-to-silica gel. It was found that an intimate mixture of 3:1 rough rice to silica gel was sufficient to dry these rice lots to 12.5% and 14.3% within 12 h, respectively. Head rice yields of desiccant-dried rice showed no considerable differences from the control. Rough-rice drying curves for all rough rice-to-silica gel mixtures followed exponential relationships

Intermittent fluctuations in the Alcator C-Mod scrape-off layer for ohmic and high confinement mode plasmas

Plasma fluctuations in the scrape-off layer of the Alcator C-Mod tokamak in ohmic and high confinement modes have been analyzed using gas puff imaging data. In all cases investigated, the time series of emission from a single spatially-resolved view into the gas puff are dominated by large-amplitude bursts, attributed to blob-like filament structures moving radially outwards and poloidally. There is a remarkable similarity of the fluctuation statistics in ohmic plasmas and in edge localized mode-free and enhanced D-alpha high confinement mode plasmas. Conditionally averaged wave forms have a two-sided exponential shape with comparable temporal scales and asymmetry, while the burst amplitudes and the waiting times between them are exponentially distributed. The probability density functions and the frequency power spectral densities are self-similar for all these confinement modes. These results are strong evidence in support of a stochastic model describing the plasma fluctuations in the scrape-off layer as a super-position of uncorrelated exponential pulses. Predictions of this model are in excellent agreement with experimental measurements in both ohmic and high confinement mode plasmas. The stochastic model thus provides a valuable tool for predicting fluctuation-induced plasma-wall interactions in magnetically confined fusion plasmas.Comment: 17 pages, 10 figure

Marine crude-oil biodegradation: a central role for interspecies interactions

The marine environment is highly susceptible to pollution by petroleum, and so it is important to understand how microorganisms degrade hydrocarbons, and thereby mitigate ecosystem damage. Our understanding about the ecology, physiology, biochemistry and genetics of oil-degrading bacteria and fungi has increased greatly in recent decades; however, individual populations of microbes do not function alone in nature. The diverse array of hydrocarbons present in crude oil requires resource partitioning by microbial populations, and microbial modification of oil components and the surrounding environment will lead to temporal succession. But even when just one type of hydrocarbon is present, a network of direct and indirect interactions within and between species is observed. In this review we consider competition for resources, but focus on some of the key cooperative interactions: consumption of metabolites, biosurfactant production, provision of oxygen and fixed nitrogen. The emphasis is largely on aerobic processes, and especially interactions between bacteria, fungi and microalgae. The self-construction of a functioning community is central to microbial success, and learning how such " microbial modules" interact will be pivotal to enhancing biotechnological processes, including the bioremediation of hydrocarbons. © 2012 McGenity et al.; licensee BioMed Central Ltd

USE OF ALTERNATIVE DEPRECIATION METHODS TO ESTIMATE FARM TRACTOR VALUES

Six depreciation methods were used to simulate the value of farm tractors with indexed and expected prices. Accuracy of simulated values was evaluated using paired t-tests of mean absolute percentage errors and forecast accuracy regression models. Results varied with age and use. Some depreciation methods were more accurate than others.Farm Management, Financial Economics,

Comparison between mirror Langmuir probe and gas puff imaging measurements of intermittent fluctuations in the Alcator C-Mod scrape-off layer

Statistical properties of the scrape-off layer (SOL) plasma fluctuations are studied in ohmically heated plasmas in the Alcator C-Mod tokamak. For the first time, plasma fluctuations as well as parameters that describe the fluctuations are compared across measurements from a mirror Langmuir probe (MLP) and from gas-puff imaging (GPI) that sample the same plasma discharge. This comparison is complemented by an analysis of line emission time-series data, synthesized from the MLP electron density and temperature measurements. The fluctuations observed by the MLP and GPI typically display relative fluctuation amplitudes of order unity together with positively skewed and flattened probability density functions. Such data time series are well described by an established stochastic framework which model the data as a superposition of uncorrelated, two-sided exponential pulses. The most important parameter of the process is the intermittency parameter, {\gamma} = {\tau}d / {\tau}w where {\tau}d denotes the duration time of a single pulse and {\tau}w gives the average waiting time between consecutive pulses. Here we show, using a new deconvolution method, that these parameters can be consistently estimated from different statistics of the data. We also show that the statistical properties of the data sampled by the MLP and GPI diagnostic are very similar. Finally, a comparison of the GPI signal to the synthetic line-emission time series suggests that the measured emission intensity can not be explained solely by a simplified model which neglects neutral particle dynamics

Johnson Space Center's regenerative life support systems test bed

The Regenerative Life Support System (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for the evaluation of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. When completed, the facility will be comprised of two large scale plant growth chambers, each with approximately 10 m(exp 2) growing area. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), will be capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in Lunar or Martian habitats; the other chamber, the Ambient Pressure Growth Chamber (APGC) will operate at ambient atmospheric pressure. The root zone in each chamber will be configurable for hydroponic or solid state media systems. Research will focus on: (1) in situ resource utilization for CELSS systems, in which simulated lunar soils will be used in selected crop growth studies; (2) integration of biological and physicochemical air and water revitalization systems; (3) effect of atmospheric pressure on system performance; and (4) monitoring and control strategies

Effective mass and quantum lifetime in a Si/Si0.87Ge0.13/Si two-dimensional hole gas

Measurements of Shubnikov de Haas oscillations in the temperature range 0.3–2 K have been used to determine an effective mass of 0.23 m0 in a Si/Si0.87Ge0.13/Si two-dimensional hole gas. This value is in agreement with theoretical predictions and with that obtained from cyclotron resonance measurements. The ratio of the transport time to the quantum lifetime is found to be 0.8. It is concluded that the 4 K hole mobility of 11 000 cm2 V−1 s−1 at a carrier sheet density of 2.2×1011 cm−2 is limited by interface roughness and short-range interface charge scattering

Wave function-dependent mobility and suppression of interface roughness scattering in a strained SiGe p-channel field-effect structure

The 4 K Hall mobility has been measured in a top-gated, inverted, modulation-doped Si/Si0.8Ge0.2 structure having a Si:B doping layer beneath the alloy. From comparisons with theoretical calculations, we argue that, unlike an ordinary enhancement-mode SiGe p-channel metal–oxide–semiconductor structure, this configuration leads to a decrease of interface roughness scattering with increasing sheet carrier density. We also speculate on the nature of the interface charge observed in these structures at low temperature