Search

An anode relative humidity (ARH) model is set up to analyze the effects of anode relative humidity on the fastest voltage decay single cell in a stack. In the ARH model, the saturation pressure related to relative humidity is established by anode pressure drop instead of using conventional empirical equation in Fluent model. First, a three dimensional (3D) model incorporating geometry and grids is established. Second, experiment is conducted including a 10-cell stack, single cell distribution and test schematic. Third, both experiment and simulation results are discussed in detail. Furthermore, for the fastest voltage decay single cell, a comparable analysis among ARH model, Fluent model and experiment is carried out at the different anode relative humidities (55%, 70%, 85% and 100%). The results show that FC10 (the furthest distance single cell from gas inlet) voltage decay is the fastest in the stack. ARH model applied to FC10 voltage decay shows good agreement with Fluent model and experiment. ARH model accuracy increases by 47% compared to Fluent model. And the error between ARH model and experiment is reduced to 3% at 350 mA/cm 2 for 100% anode relative humidity. FC10 species molar concentration distributions inside fuel cell in each case are non-uniform. [ABSTRACT FROM AUTHOR]

A set of unconventional electro-osmosis (EO) experiments using intermittent current was conducted on dredger fill samples from a land reclamation site at Liaoning Coast in China. This study focused on the quantitative evaluation of the use of EO to enhance the effect of surcharge preloading consolidation, thus improving the mechanical and physical properties of soil. The sand wells were used to avoid excessive consumption of electrical energy in the process of repeated seepage. A systematic comparative study on preloading combined with electro-osmotic consolidation shows that the EO coefficient decreases with water content. The increase in shear strength at a potential difference of 15 V combined with a loading of 2.67 kPa is approximately twice as high as that of preloading only, but the electrical power consumption is merely 23% more. Mercury injection tests and scanning electron microscopy images showed that the subsidence mechanism of Liaoning Bay soil is the change of macropores to mesopores. Furthermore, using the combined method of EO and preloading results in even treatment effects in different soil depths. Electrochemical reaction and economic benefit are further analyzed. All of these results indicate that combining preloading and EO ensures better performance than individual operation. [ABSTRACT FROM AUTHOR]

Main conclusion: A gene targeting method has been developed, which allows the conversion of 'breeding stacks', containing unlinked transgenes into a 'molecular stack' and thereby circumventing the breeding challenges associated with transgene segregation. A gene targeting method has been developed for converting two unlinked trait loci into a single locus transgene stack. The method utilizes intra-genomic homologous recombination (IGHR) between stably integrated target and donor loci which share sequence homology and nuclease cleavage sites whereby the donor contains a promoterless herbicide resistance transgene. Upon crossing with a zinc finger nuclease (ZFN)-expressing plant, double-strand breaks (DSB) are created in both the stably integrated target and donor loci. DSBs flanking the donor locus result in intra-genomic mobilization of a promoterless selectable marker-containing donor sequence, which can be utilized as a template for homology-directed repair of a concomitant DSB at the target locus resulting in a functional selectable marker via nuclease-mediated cassette exchange (NMCE). The method was successfully demonstrated in maize using a glyphosate tolerance gene as a donor whereby up to 3.3 % of the resulting progeny embryos cultured on selection medium regenerated plants with the donor sequence integrated into the target locus. The process could be extended to multiple cycles of trait stacking by virtue of a unique intron sequence homology for NMCE between the target and the donor loci. This is the first report that describes NMCE via IGHR, thereby enabling trait stacking using conventional crossing. [ABSTRACT FROM AUTHOR]

Harvested hay or biomass are traditionally baled for better handling and they are transported to the outlet for final utilization. For better management of bale logistics, producers often aggregate bales into stacks so that bale-hauling equipment can haul multiple bales for improved efficiency. Objectives of this research include simulation of bale collection logistics after forming subfield stacks, evaluation of location effects of bale stack and field outlet, the number of stacks, transported bales/trip, and other field parameters on logistics distances (aggregation, transportation, and total). The software ‘R’ performed the simulation, statistical analysis, and data visualization. Formation of bale stacks decoupled aggregation and transportation components. Stacks formation thus allows for aggregation and transportation to be performed at different times. Increasing the number of subfield stacks and the number of transported bales/trip significantly reduced the total logistics distances. The order for the best bale stack and outlet locations was: middle, near middle, mid-edge along the length, mid-edge along the width, and finally, corners. Except for swath and windrow variation, the studied field variables had a highly significant influence on the logistics distances. Increased bales/trip (≥6) reduced the variations of outlet locations. Locating the field outlet at or near the center of the field along with an appropriate number of square subfields with stacks at the middle, and increased bales/trip will be the most efficient infield logistics strategy. [ABSTRACT FROM AUTHOR]

In this study, an experimental-based comparative analysis among different options to the baffles settup in a drying kiln was carried. The experiments consisted in measuring the air velocity in different points located at the outlet face of stacks. The results showed that the position of baffles inside a drying kiln plays an important role on mean air velocity and its uniformity withing the wood stacks. In the analyzed case the best option to place the baffles was in the middle of the stacks. [ABSTRACT FROM AUTHOR]

The understanding and description of collectively excited multichromophores is of crucial importance for many areas of basic and applied research. DNA has been used for the construction of well-defined heterochromophoric stacks. Electronic coupling among non-adjacent chromophores of the same type leads to the co-existence of PDI and pyrene H-aggregates in hybrids composed of alternating chromophore stacks. [ABSTRACT FROM AUTHOR]

Abstract: Reverse electrodialysis (RED) is a sustainable technology for salinity gradient energy harvesting. In order to make the process economically competitive, it is desirable to operate it at the highest possible net power density, which depends on the RED stack geometry and on the pressure drop along its pathways and, thus, on the energy spent for solutions pumping. The fluid flow in RED stacks generally occurs in rectangular compartment channels, equipped with spacers. The effects of spacers design and properties have been studied extensively in recent years. However, the other possible causes for a RED stack and their relative impact on the process performance have not yet been systematically studied. In this study the partial pressure drops in (1) distribution ducts, (2) branches, (3) beams, (4) due to sudden section expansion between the beam and the compartment channel and (5) in the compartment channel were taken into consideration. A model for the total pressure drop inside a RED stack, with a parallel fluid flow distribution through the compartments, is proposed and experimentally validated for lab-scale RED stacks with sheet flow spacers and compared with an open channel (spacer-free) design. The importance of each partial pressure drop was then evaluated quantitatively through model simulations for industrial-scale stacks with an increasing number of cell pairs. It was found that the net power density decreases when the cell-pair number increases, since the partial pressure drop in the branches becomes dominant. Moreover, the possible reasons for a non-uniform fluid flow distribution are discussed, thus making the proposed model useful for planning and/or optimization of RED stacks design. [Copyright &y& Elsevier]

Abstract: Volatile organic compounds (VOCs) are potentially harmful air pollutants that are commonly encountered in urban environments. Various chemicals known to produce VOCs are used in laboratory fume hoods; however little research has been done to show the effect of such chemicals and associated VOCs on the local air quality. This study aims to assess the concentration of various VOCs emitted from the exhaust stacks of rooftop fume hoods mounted on laboratory buildings, as well as to determine factors that contribute to different concentrations of commonly encountered VOCs. A total of six university campus buildings, comprising four laboratory buildings and two non-laboratory buildings as controls, were selected as case studies. VOCs were sampled using activated charcoal tubes in front of fume hood exhausts located on the rooftops of buildings and were analyzed GC/FID. Factors such as meteorological conditions and the amount of chemicals utilized in the building of interest were investigated. A total of 11 individual compounds were quantified in the samples collected. The concentrations of 11 VOCs at laboratory buildings were significantly higher (GM; 184.74 μg/m3, GSD; 3.38) than those of non-laboratory buildings (GM; 12.1 μg/m3, GSD; 1.64, p < 0.001). The concentrations of 10 individual compounds emitted from laboratory buildings were significantly higher than those emitted from non-laboratory buildings (p < 0.001) with the exception of m- and p-xylene (p = 0.155). We found that the amount of chemical use was the predominant factor determining the composition and concentrations of VOCs found (p < 0.001). From this study, we suggest that installation of an air purification system in fume hood ventilation systems is necessary to prevent atmospheric pollution and adverse health effects in university populations, as well as supporting efforts towards creating ‘green campus’ environments. [Copyright &y& Elsevier]

Abstract: Rotary ultrasonic machining (RUM) has been successfully used to drill Ti (titanium and its alloy), CFRP, and CFRP/Ti stacks. In all studies on RUM reported in the literature, feedrate was fixed during each experimental test. It has been shown that low feedrate should be used for RUM of Ti, but RUM of CFRP could be done using feedrate 10 times higher. This paper, for the first time, reports a study on RUM of CFRP/Ti stacks using variable feedrate (high feedrate for CFRP and low feedrate for Ti). It also makes comparisons on RUM of CFRP/Ti stacks using fixed and variable feedrate. [Copyright &y& Elsevier]

In this work, statistical design was applied for the optimization of process parameters for the biofiltration of toluene using mixed microorganisms obtained from pharmaceuticals wastewater sludge in a packed bed biofilter. The effects of process parameters such as gas flow rate, initial toluene concentration, height of the packing material, and temperature on removal efficiency (RE) of toluene was studied and optimized using response surface methodology. Using Box-Behnken Design, 30 experiments were carried out for the four test variables. From the results, the optimum condition for maximum RE was found to be: gas flow rate-0.01 m h, initial toluene concentration-0.25 g m, packing height-0.75 m, and temperature-31 °C. At these optimized conditions, the removal efficiency of toluene was found to be 95 %. A high R value of greater than 0.9 indicates the fitness of the model to predict the experimental data. Biokinetic studies led to a good fit between experimental data and mathematical equations, yielding a calculated maximum toluene degradation rate of 140.42 g m h with a half-velocity constant, K, of 0.076 g m. [ABSTRACT FROM AUTHOR]

Some lichens that occur in mountains and arid regions have developed an unusual anatomy resembling window-leaved plants. In these lichens, algal cells occur in thick vertical stacks (algal stacks) separated by vertical channels of light-transferring fungal hyphae (fungal stacks). We present experimental evidence that this anatomy permits higher rates of area-based CO2 assimilation in strong light, but that it also leads to higher respiration resulting in higher compensation irradiance. The net effect of this anatomy must be beneficial in regions of high insolation, as it has arisen many times in different parts of the world, and in unrelated lichens, and these lichens often dominate the communities in which they occur. [ABSTRACT FROM AUTHOR]

Abstract: Stack-pretreatment is introduced to gain higher biogas production from corn stover through solid state anaerobic digestion. The purpose of this study is to find the effects of naturally microbial pretreatment on stalk lignin, cellulose and hemicellulose degradation, and biogas production. The result indicates that the corn straws which had been stack-pretreated for 20 days decreases of the content of the middle corn straws cellulose, hemi-cellulose and lignin by 5.8%, 16.8% and 5.7% respectively lower than that of the untreated samples. The highest cumulative biogas yield for 60-day digestion was obtained in B group, which was 23.2% higher than that of A group, 29.1% higher than H group and also 40.7% higher than I group. The result indicates the biogas yield of anaerobic digestion of the pretreated corn stover mixed with cow dung is higher than that of the untreated ones mixed with cow dung, and higher than that of the untreated ones alone, also higher than the cow dung alone. The biogas yield of the pretreated corn stover mixed with cow is higher than the pretreated ones with the sludge. [Copyright &y& Elsevier]

Abstract: A dual purpose greenhouse was designed, developed and tested for simultaneously producing full crop on the greenhouse floor and nursery plants on the existing north wall (in optimized stacks) for higher economic gains. Using solar geometry, it was computed that the optimum ratio between the height of two consecutive stacks (H) and width of the tray (W) is 1.07 at 31°N. The optimally designed nursery trays were mounted in two stacks on the north wall in such a way that at solar noon no fraction of solar radiation leaves through it and also does not cast any shadow of the upper stack onto the lower stack and on the plants grown on the floor. Nursery plants of tomato crop were raised on these two stacks having three trays of length (L) as 160cm and width (W) as 67cm size each with H as 72cm. During the four winter months, the small greenhouse of 600cm×400cm size can be used commercially to produce about 45,000 nursery plants by completing five cycles. This can be done in addition to the normal crop raised on the greenhouse floor and significant extra revenue can be generated. These returns can further be increased at higher latitudes because at constant H, width of the tray (W) increases with increase in latitude. Economic analysis showed that for tomato crop, currently the cost of greenhouse construction (without north wall stacks) can be recovered after five years time but with simultaneous nursery raising on the north wall, the whole investment cost (greenhouse and stacks) can be recovered in less than two year’s time and thereafter it becomes a profitable venture. Optimum number of stacks and other stack parameters for realistic north wall heights of 210cm, 260cm and 310cm have been computed and discussed at 30°N, 35°N, 40°N, 45°N and 50°N latitudes. [Copyright &y& Elsevier]

In wheat, the use of gene 'pyramids' or 'stacks' of major genes that confer resistance to all local strains of the fungal stem rust pathogen Puccinia graminis f. sp. tritici (Pgt) can increase durability of resistance where wheat cultivars with the single gene components are not widely deployed. Stacking two or more resistance genes becomes a breeding challenge, particularly when pathogen races that discriminate the genes are not available. The use of DNA markers and doubled-haploid technology provides a route for producing lines homozygous for multiple resistance genes. We have applied this approach to produce gene pyramids of two or more of the stem rust resistance genes Sr24 and new sources of SrR, Sr31 and Sr26 on reduced alien chromatin in the genetic backgrounds of Westonia and Pavon wheat. These genes, which are all derived from 'alien' sources ( SrR and Sr31 from rye, Sr24 and Sr26 from Agropyron elongatum) each provide resistance to all currently known pathotypes of Pgt in Australia, and SrR and Sr26 also provide resistance against all the variants of stem rust race Ug99 (TTKS group). [ABSTRACT FROM AUTHOR]

Co-incineration of wastes started more than 20 years ago. In the last 10 years, the use of alternative fuels in the cement industry is continuously increasing. The use of solid wastes in cement kilns is one of the best technologies for a complete and safe destruction of these wastes, due to the fact that there is a simultaneous benefit of destroying wastes and getting the energy. However, particulate matters (PM) and gaseous chemicals emitted from a source into the environment could be directly transmitted to humans through air inhalation. Therefore, for accurate health risk estimation, the emission of pollutants must be determined. In this work, the analysis of the emission of different pollutants when replacing partially the fuel type used in a cement kiln is done. PM, PM10, heavy metals and inorganic pollutants are analyzed. The methods used for sampling and analysis are the standard methods suggested by the EU regulations for stack analysis. Experimental results have shown the encouraging results: in particular clinker characteristics were unmodified, and stack emissions (NOx, SO2 and CO mainly) were in the case of tires, slightly incremented but remaining almost always below the law imposed limits, and in some cases were even decreased. [ABSTRACT FROM AUTHOR]

Discrete, well-defined stacks of the polarized aromatic pyrene-4,5-dione (1) were assembled in the cavities of organic-pillared coordination cages (2). The number (n) of stacked guests depends on the pillar length, and up to quintuple stacks (n = 5) were observed when long (16.5 Å) organic pillar ligands were incorporated. As previously reported, pyrene-4,5-dione (1) assembles into infinite columnar stacks in the solid state, but the present work demonstrates that the polarized 1 has a strong propensity to stack in layers even in the absence of crystal packing effects. For n = 2 and 3 structures, crystallographic studies revealed that 1 stacks by π-π interactions in the cavity in such a way that a net dipole moment is canceled. These results emphasize the important role of dipole-dipole interactions as well as π-stacking interactions in the formation of columnar stacks of 1. [ABSTRACT FROM AUTHOR]

Abstract: By monitoring silage temperature at different locations inside silage stacks, it is possible to detect any significant increases in temperature occurring during silage decomposition. The objectives of this study were: (1) to develop novel noninvasive wireless sensor nodes for measuring the temperature inside silage stacks; (2) to design a suitable sensor protection housing that prevents physical and chemical damage to the sensor; and (3) to mathematically model temperature variations inside a silage stack, using system identification techniques. The designed wireless nodes were used to monitor temperatures in a full-sized silage stack over 53 days. Results showed that the wireless sensor nodes accurately monitored the temperature inside the silage stack at depths of 25 and 50cm and reliably transmitted the measured data through the network; between 98.9% and 99.4% of the packets disseminated from the sensor nodes were successfully delivered to the gateway. The reliable performance of the network confirmed the correct choice of network characteristics (i.e., frequency range of 433MHz, a handshaking communication protocol, and 10mW transmission power). The designed sensor housings were capable of withstanding the high loads that occurred during ensiling, storage, and feed-out. Mathematical models estimating the relations between the silage temperatures (at depths of 25 and 50cm) and air and soil temperatures were obtained. Black-box modeling using the prediction error method (PEM) was selected as the identification method. Among different black-box models such as ARX, ARMAX, output-error (OE), and Box–Jenkins (BJ), with different model orders, a third-order Box–Jenkins model structure gave the best performance in terms of prediction accuracy. The success rate of the models proposed for silage temperature prediction ranged between 90.0% and 94.3%. Furthermore, there was no significant autocorrelation remaining in the residuals. The results of this study indicate that the designed wireless sensor nodes could potentially be used for detecting silage decomposition processes and improving the efficacy of silage conservation systems. [Copyright &y& Elsevier]

Abstract: The effect of two different diet types (concentrate feed+hay and grazing) on the pharmacokinetic profiles of triclabendazole following oral administration in goats was investigated. A total of 12 goats were randomly allocated into two groups which were either indoor and fed concentrate+hay ration (housed group) or were grazing on pasture (grazing group). Triclabendazole was administered orally to animals in two groups at 10mg/kg bodyweight. Blood samples were collected from 1h to 192h post-treatment and analyzed by high performance liquid chromatography (HPLC). Feeding with different diets significantly effected the plasma disposition of triclabendazole sulphoxide. Maximum plasma concentration (C max: 13.22±2.81μg/ml), time to reach maximum plasma concentration (t max: 18.4±2.19h), area under the curve (AUC: 613±137μgh/ml), half-life (t 1/2: 24.77±1.94h) and mean resident time (MRT: 40.22±4.36h) of triclabendazole sulphoxide in housed group were significantly different from those of grazing group (C max: 10.17±1.51μg/ml, t max: 14.0±2.19h, AUC: 406±98μgh/ml), t 1/2: 16.16±1.17h and MRT: 34.48±4.40h). It is concluded that anthelmintically more active sulphoxide metabolite has higher plasma concentration when triclabendazole is administered to goats fed with concentrate feed+hay compared to grazing goats. [Copyright &y& Elsevier]

In conjunction with investigating the quality of imported grass hays, the present study set out to develop an evaluation standard. A total of 123 hay samples were tested: 70 of timothy hay, 23 of sudangrass hay, 20 of oat hay and 10 of bermudagrass hay. Crude protein content, nitrogen cell wall free extract (NCWFE) content, Oa (organic a fraction in cell wall, non-lignified portion of cell wall) content and Ob (organic b fraction in cell wall, lignified portion of cell wall) content were measured for each sample, and the values of these were used as the basis for the determination of digestible carbohydrate content and dry matter intake (DMI). The variation in crude protein, NCWFE, Oa and Ob content within each grass species was large. The coefficients of variation for the chemical composition of all 123 samples were 24.9% for crude protein, 37.4% for NCWFE, 30.7% for Oa and 11.0% for Ob. Because variation in composition was large, variations in digestible carbohydrate content and DMI within each species were also large. On the basis of the mean values of chemical composition, it was determined that the harvesting period was after the flowering stage. Evaluation standards were set using a five-point scale (5, excellent; 4, good; 3, medium; 2, low; 1, poor), based on the 123 samples tested in the present study, using the mean values and standard deviations of chemical parameters, digestible carbohydrate content and DMI. Consequently, in assessing DMI (per bodyweight of 600 kg), a grade of 5 was given for values of 14.3 kg or higher, 4 for values between 11.5 and 14.3 kg, 3 for values between 8.7 and 11.5 kg, 2 for values between 5.9 and 8.7 kg, and 1 for values lower than 5.9 kg. [ABSTRACT FROM AUTHOR]