Reversibly crosslinked self‐healing PCL‐based networks

Poly(ε‐caprolactone) (PCL)‐based thermoreversible networks with self‐healing properties were prepared through Diels–Alder (DA) and retro‐DA reactions. Bis‐ or Tris‐maleimide compounds and a series of copolymer(caprolactone‐diene) PCL_XF_Y (X: degree of polymerization and Y: furan‐average functionality) with Y between 2.4 and 4.9 were used. The successive sequences of formation and dissociation of polycaprolactone networks via DA and retro‐DA reactions were observed repeatedly by dynamic mechanical analyses (DMA) and their gel‐temperatures determined. The cross‐linking densities, thermal properties, and thermal reversibility of the PCL_XF_Y/multimaleimide polymers have been modulated by the structure and functionalities of the used diene and dienophile moieties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Growth optimization of thraustochytrid strain 12B for the commercial production of docosahexaenoic acid

High yield of cell, lipid, and docosahexaenoic acid (DHA) from thraustochytrid strain 12B were achieved without the use of a complex medium and at low NaCl concentration which is detrimental to avoid unnecessary corrosion of steel tank equipment during cultivation. Culture medium that contained only 0.1% NaCl and 1% MgSO₄ in an organic base solution containing 8% glucose, 1% yeast extract, and 1% peptone, referred here as NM medium, was found to be as good as or superior to the culture medium prepared from 50%(v/v) seawater with percentage lipid/dry cell weight (DCW) of 66.4%(w/w) and DHA yield up to 43.95 mg/g DCW for the thraustochytrid strain 12B. The NM medium was also applicable to the prominently high DHA-accumulating Schizochytrium limacinum SR21, and therefore this medium could probably be used for other thraustochytrid and other types of microbial strains as well.     

UHF Band Short Range Propagation Model

The purpose of this study is to characterize the indoor and indoor–outdoor propagation in different scenarios, using monopole antennas working at 410 and 890 MHz. Propagation of narrow band and wide bands have been studied. In scenarios with a continuous variation of the distance between the transmitter and receiver antenna (1 D scenarios), we use a log-distance path loss model to determine the equations that describe the mean value of the path loss. In scenarios where the position of the receiver is not a uniform function of the distance between the transmitter and the receiver, we represent the basic propagation gain as a function of the measurement point index. Results show that the indoor propagation gain can be described using two slopes propagation model. For the multiwall attenuation loss it is shown that each wall has an attenuation of almost 2.5 dB at 410 MHz increasing to almost 4 dB at 890 MHz. The obstruction gain (loss) due to human beings shows that this can be within a 40 dB interval.     

WCDMA Multiclass Downlink Capacity and Interference Statistics of Cigar-Shaped Microcells in Highways

In this paper, the multiclass downlink capacity and the interference statistics of the sectors of a cigar-shaped microcells using wideband code-division multiple-access with soft handover mode are analyzed. The two-slope propagation model with log-normal shadowing is used in the analysis where a model of 8 cigar-shaped microcells is utilized. The performance of the downlink is studied for different [sector range R, standard deviation of the shadowing ( $\sigma _{1}$ and $\sigma _{2})$ and propagation exponents ( $\text{ s}_{1}$ and $\text{ s}_{2})$ ]. It is found that increasing the sector range from 500 to 1,000 m will increase the sector downlink capacity. Also, it is found that increasing the value of the propagation parameters ( $\sigma _{1}$ and $\sigma _{2})$ will reduce the downlink sector capacity. It is noticed that, the effect of changing the propagation exponent $\text{ s}_{1}$ is null while increasing the propagation exponent $\text{ s}_{2}$ will increase the downlink capacity.     

Efficient Decoding for Generalized Quasi-Orthogonal Space–Time Block Codes

Space–time coding can achieve transmit diversity and power gain over spatially uncoded systems without sacrificing bandwidth. There are various approaches in coding structures, including space–time block codes. A class of space–time block codes namely quasi-orthogonal space–time block codes can achieve the full rate, but the conventional decoders of these codes experience interference terms resulting from neighboring signals during signal detection. The presence of the interference terms causes an increase in the decoder complexity and a decrease in the performance gain. In this article, we propose a modification to the conventional coding/decoding scheme that will improve performance, reduce decoding complexity, and improve robustness against channel estimation errors as well.     

Enhancing Inflow Forecasting Model at Aswan High Dam Utilizing Radial Basis Neural Network and Upstream Monitoring Stations Measurements

The Nile River is considered the main life artery for so many African countries especially Egypt. Therefore, it is of the essence to preserve its water and utilize it very efficiently. Developing inflow-forecasting model is considered the technical way to effectively achieve such preservation. The hydrological system of the Nile River under consideration has several dams and barrages that are equipped with control gates. The improvement of these hydraulic structures’ criteria for operation can be assessed if reliable forecasts of inflows to the reservoir are available. Recently, the authors developed a forecasting model for the natural inflow at Aswan High Dam (AHD) based on Artificial Intelligence (AI). This model was developed based on the historical inflow data of the AHD and successfully provided accurate inflow forecasts with error less than 10%. However, having several forecasting models based on different types of data increase the level of confidences of the water resources planners and AHD operators. In this study, two forecasting model approach based on Radial Basis Function Neural Network (RBFNN) method for the natural inflow at AHD utilizing the stream flow data of the monitoring stations upstream the AHD is developed. Natural inflow data collected over the last 30 years at four monitoring stations upstream AHD were used to develop the model and examine its performance. Inclusive data analysis through examining cross-correlation sequences, water traveling time, and physical characteristics of the stream flow data have been developed to help reach the most suitable RBFNN model architecture. The Forecasting Error (FE) value of the error and the distribution of the error are the two statistical performance indices used to evaluate the model accuracy. In addition, comprehensive comparison analysis is carried out to evaluate the performance of the proposed model over those recently developed for forecasting the inflow at AHD. The results of the current study showed that the proposed model improved the forecasting accuracy by 50% for the low inflow season, while keep the forecasting accuracy in the same range for the high inflow season.     

Mitigation of Major Peanut Allergens by Pulsed Ultraviolet Light

Peanut allergy represents one of the most severe IgE-mediated reactions with food, but to date, the only effective way to prevent peanut allergy is total avoidance. If allergens could be mitigated during food processing before a product reaches the consumer, this would substantially lessen the food allergy problem. The efficacy of pulsed ultraviolet light (PUV), a novel food processing technology, on reducing peanut allergens, was examined. This study revealed for the first time that PUV was also capable of deactivating Ara h 2, the most potent allergenic protein of peanut. Protein extracts from raw and roasted peanuts were treated for 2, 4, and 6?min and peanut butter slurry was treated for 1, 2, and 3?min in a Xenon Steripulse XL 3000? PUV system. The distance from the central axis of the lamp was varied at 10.8, 14.6, and 18.2?cm. The SDS?CPAGE showed a reduction in the protein band intensity for Ara h 1, Ara h 2, and Ara h 3 at the energy levels ranging from 111.6 to 223.2?J/cm². Reduction of the protein band intensity for peanut allergens increased with treatment time but decreased with increased distance from the PUV lamp. The ELISA for peanut extracts and peanut butter slurry showed a reduction in IgE binding of up to 12.9- and 6.7-folds, respectively, compared to control.     

Antibacterial activity of chitosan against Aeromonas hydrophila

The effect of chitosan on growth and production of haemolysin by Aeromonas hydrophila was investigated as well as the effects of temperature, pH, salts and irradiation on the antibacterial activity of chitosan. It was found that chitosan affected growth and haemolysin production of A. hydrophila in varying degrees compared to the control. Growth and haemolysin production were clearly suppressed at 0.04% of chitosan. Suppression was more effective at pH 6.0 than at pH 7.0. The bactericidal effects of chitosan increased with increasing temperature and decreasing pH. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Sodium ions at concentrations of 10 and 25 mM also reduced chitosan's activity. Irradiation of chitosan at 150 kGy under dry condition was effective in slightly increasing its activity.     

Geological Engineering,Civil Engineering,Traffic and Transportation Engineering Electrical capacitance volume tomography for measurement soil water infiltration in vessel experiments简

Electrical capacitance volume tomography （ECVT） is a recently-developed technique for real-time, non-invasive 3D monitoring of processes involving materials with strong contrasts in dielectric permittivity. This work is first application of the method to visualization of water flow in soil. We describe the principles behind the method, and then demonstrate its use with a simple laboratory infiltration experiment. 32 ECVT sensors were installed on the sides of an empty PVC column. Water was poured into the column at a constant rate, and ECVT data were collected every second. The column was then packed with dry sand and again supplied with water at a constant rate with data collected every second. Data were analyzed to give bulk average water contents, which proved consistent with the water supply rates. Data were also analyzed to give 3D images （216 voxels） allowing visualization of the water distribution during the experiments. Result of this work shows that water infiltration into the soil, wall flow, progress of the unstable wetting front and the final water distribution are clearly visible.     

The effects of highways on school segregation

The purpose of this paper is to investigate the effects of interstate highway building on school segregation in US cities. The simple ordinary least squares (OLS) model might suffer from endogeneity bias and therefore an instrumental variables (IV) model is employed to account for endogeneity of highway routes. Dissimilarity and interaction indices are used to measure segregation and the results of the OLS and IV models indicate that school segregation increased due to the additions to the highway system. The estimates suggest that highways can explain 7–10% of the variation in school segregation.