Fermentative bioenergy production from distillers grains using mixed microflora

The feasibility of hydrogen production from distillers grains substrate, an industrial cellulosic waste, was investigated. A substrate concentration of 80 g/L gave the maximum production at 50 °C and pH of 6.0 using sewage sludge. Four controllable factors with three levels: seed sludge (two sewage sludges and cow dung), temperature (40, 50, and 60 °C), pH (6, 7 and 8) and seed pretreatment (none, heat, and acid) were selected in Taguchi experimental design to optimize fermentation conditions. The peak hydrogen and ethanol productions were found with heat-treated cow dung seed, substrate concentration 80 g/L, 50 °C and pH 6. The peak hydrogen production rate and hydrogen yield were 7.9 mmol H₂/L/d and 0.40 mmol H₂/g-COD respectively whereas the peak ethanol production was 3050 mg COD/L and rate 0.22 g EtOH/L/d. A total bioenergy yield of 41 J/g substrate was obtained which was 21% and 79% from hydrogen and ethanol respectively.     

Fermentative biohydrogen production from starch-containing textile wastewater

The present study deals with the biohydrogen production from starch-containing wastewater collected from the textile industry in Taiwan. The effects of inoculums collected from different sources (sewage sludge, soil and cow dung), substrate concentrations (5–25 g COD/L) and pH (4.0–8.0) on hydrogen production from wastewater were investigated.     

Pilot-scale hydrogen fermentation system start-up performance

A high-rate hydrogen production process able to produce H₂ at a maximum rate of 15 L/L/h was successfully developed by the Feng Chia University (FCU) biohydrogen research team. This highly efficient hydrogen fermentation system includes a 400 L pilot-scale system constructed for determining scale-up operation parameters for commercializing the bioH₂ production technology. The pilot-scale system is composed of a feedstock tank, mixing system, fermentor, gas/liquid separator and automatic control system. The fermentor is fed with sucrose (20 g COD/L) and operated at 35 °C. A batch strategy is used for system start-up. The fermentor was first operated in a batch mode for two days and then switched to a continuous-feeding mode (HRT 12 h) for one month. During the continuous operation, pH notably affected H₂ production efficiency and bacterial community. For the first 14-day operation, the H₂ production rate increased from 0.017 to 0.256 L/L/h with a pH variation from 5.0 to 7.0. The DGGE results indicate the presence of two Clostridium species (namely, Clostridium butyricum and Clostridium pasteurianum) in the fermenter. Stable hydrogen production rate was obtained at pH 5.5–6.0 when C. pasteurianum became dominant in the mixed culture.     

Differences in attentional strategies by novice and experienced operating theatre scrub nurses.

This study investigated the effect of nursing experience on attention allocation and task performance during surgery. The prevention of cases of retained foreign bodies after surgery typically depends on scrub nurses, who are responsible for performing multiple tasks that impose heavy demands on the nurses' cognitive resources. However, the relationship between the level of experiences and attention allocation strategies has not been extensively studied. Eye movement data were collected from 10 novice and 10 experienced scrub nurses in the operating theater for caesarean section surgeries. Visual scanning data, analyzed by dividing the workstation into four main areas and the surgery into four stages, were compared to the optimum expected value estimated by SEEV (Salience, Effort, Expectancy, and Value) model. Both experienced and novice nurses showed significant correlations to the optimal percentage dwell time values, and significant differences were found in attention allocation optimality between experienced and novice nurses, with experienced nurses adhering significantly more to the optimal in the stages of high workload. Experienced nurses spent less time on the final count and encountered fewer interruptions during the count than novices indicating better performance in task management, whereas novice nurses switched attention between areas of interest more than experienced nurses. The results provide empirical evidence of a relationship between the application of optimal visual attention management strategies and performance, opening up possibilities to the development of visual attention and interruption training for better performance. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Hot topic: Black spot defect in Cheddar cheese linked to intramammary teat sealant

The objective of this work was to characterize a novel appearance defect found in Cheddar cheese, heretofore referred to as black spot defect (BSD), and to determine an etiology. Uniformly distributed throughout the cheese mass, BSD appears as small spherical black spots from 0.20 to 4.7 mm in diameter and at an average frequency of about 2 spots per kg of cheese. To date, BSD has only been found in aged Cheddar cheese. Selected elemental analysis found the BSD region in cheese to have average concentrations of the element bismuth of approximately 400 μg/g, representing an approximately 2,500-fold increase over native levels of bismuth in cheese. Transmission electron microscopy analysis of the BSD region revealed amorphous solid structures and one-dimensional hair-like structures, neither of which was present in non-BSD regions. Such amorphous “nanorod” structures can be formed by the crystallization of bismuth III sulfide and are proposed to be a source of black discoloration. We hypothesize that localized bismuth salts entrained within the cheese curd react with hydrogen sulfide generated during aging to generate bismuth III sulfide. We further propose that the presence of localized bismuth salt precursor results from residual levels of a commercial intra-mammary teat sealant containing bismuth subnitrate that becomes unintentionally entrained within the cheese milk.     

Envelope-constrained filters: adaptive algorithms

We consider an envelope-constrained (EC) optimal filter design problem involving a quadratic cost function and a number of linear inequality constraints. Using the duality theory and the space transformation function, the optimal solution of the dual problem can be computed by finding the limiting point of an ordinary differential equation given in terms of the gradient flow. An iterative algorithm is developed via discretizing the differential equation. From the primal-dual relationship, the corresponding sequence of approximate solutions in the original EC filtering problem is obtained. Based on these results, an adaptive algorithm is constructed for solving the stochastic EC filtering problem in which the input signal is corrupted by an additive random noise. For illustration,a practical example is solved for both noise-free and noisy cases     

Process analysis and optimization of biodiesel production from soybean oil

The overall goal of this work is to design and optimize a biodiesel production process from soybean oil. To achieve this goal, several inter-connected activities were undertaken. First, an initial flowsheet for the process was synthesized. The performance of this flowsheet along with the key design and operating criteria were identified by conducting computer-aided simulation using ASPEN Plus. Various scenarios were simulated to provide sufficient understanding and insights and to select a base-case flowsheet. Next, mass and energy integration studies were performed to reduce the consumption of material and energy utilities, improve environmental impact, and enhance profitability. Capital cost estimation was carried out using the ICARUS Process Evaluator computer-aided tool linked to the results of the ASPEN Plus simulation. The operating cost of the process was estimated using the key information on process operation such as raw materials, utilities, and labor. A profitability analysis was carried out by examining the return on investment and the payback period. It was found that the cost of soybean oil is the largest contributor to the production cost. A sensitivity analysis was carried out to determine the effect of soybean oil prices on the process profitability.     

Design of robust envelope-constrained filter with orthonormal bases

In the continuous-time envelope-constrained (EC) filtering problem using an orthonormal filter structure, the aim is to synthesize an orthonormal filter such that the noise enhancement is minimized while the noiseless output response of the filter with respect to a specified input signal stays within the upper and lower bounds of the envelope. The noiseless output response of the optimum filter to the prescribed input signal touches the output boundaries at some points. Consequently, any disturbance in the prescribed input signal or error in the implementation of the optimal filter will result in the output constraints being violated. In this paper, we review a semi-infinite envelope-constrained filtering problem in which the constraint robustness margin of the filter is maximized, subject to a specified allowable increase in the optimal noisy power gain. Using a smoothing technique, it is shown that the solution of the optimization problem can be obtained by solving a sequence of strictly convex optimization problems with integral cost. An efficient optimization algorithm is developed based on a combination of the golden section search method and the quasi-Newton method     

Neural network cost estimates for heart bypass surgery

This paper reports on the results of using artificial neural network (ANN) technology to estimate treatment costs of heart bypass patients based on their diagnostic condition and clinical criteria. Our applications include: (1) predicting total episode cost using clinical data; (2) a method for providing rapid feedback to assess change in total costs within a turbulent environment; and (3) a procedure for identifying activity-based cost driver candidates that would normally not surface from an analysis of accounting data. Clinical data were collected on 250 heart bypass patients at the University of Ottawa Heart Institute. The data analysed support the following conclusions: (1) clinical and diagnostic indicators obtained before surgery for individual patients can be used to estimate the total cost of their heart bypass surgery; (2) the average cost estimate error decreases as we add clinical information available during and after the surgical event; (3) the procedure used to estimate individual patient cost does not require access to accounting records; (4) the forecasting system we describe may improve exception reporting for individual patients by tracking costs and clinical criteria on a real-time basis throughout the treatment episode.     

Semantic retrieval of multimedia by concept languages: treating semantic concepts like words

This paper presents a retrieval approach that uses concept languages to deal with nonverbally expressed information in multimedia. In operation, a finite number of elecepts of a concept language are identified and used to index multimedia documents. The elecepts then allow a large number of compound semantic queries to be expressed and operated as sentences of elecepts. We believe that managing semantics by concept languages is a prudent proposition. Not only does it extend an intuitive query regime where semantic queries can be specified more expressively and extensively, the approach also allows concept detection to be restricted to a more manageable sum of semantic classes. Two example applications are discussed in the paper. One uses a color artistry language to retrieve art images and the other utilizes a tennis concept language to retrieve tennis videos