Performance of laser bonded glass/polyimide microjoints in cerebrospinal fluid

In this paper, laser bonded microjoints between glass and polyimide is considered to examine their potential applicability in encapsulating neural implants. To facilitate bonding between polyimide and glass, a thin titanium film with a thickness of 2 μm was deposited on borosilicate glass plates by a physical vapor deposition (PVD) process. Titanium coated glass was then joined with polyimide by using a cw fiber laser emitting at a wavelength of 1.1 μm (1.0 W) to prepare several tensile samples. Some of the samples were exposed to artificial cerebrospinal fluid (aCSF) at 37^∘C for two weeks to assess long-term integrity of the joints. Both the as-received and aCSF soaked samples were subjected to uniaxial tensile loads for bond strengths measurements. The bond strengths for the as-received and aCSF soaked samples were measured to be 7.31 and 5.33 N/mm, respectively. Although the long-term exposure of the microjoints to aCSF has resulted in 26% reduction of bond strength, the samples still retain considerably high strength as compared with the titanium-polyimide samples. The failed glass/polyimide samples were also analyzed using optical microscopy, and failure mechanisms are discussed. In addition, a two dimensional finite element analysis (FEA) was conducted to understand the stress distribution within the substrate materials while the samples are in tension. The FEA results match reasonably well with the experimental load-displacement curves for as-received samples. Detailed discussion on various stress contours is presented in the paper, and the failure mechanisms observed from the experiment are shown in good agreement with the FEA predicted ones.     

Tensile behavior of clay-filled polyester composites

In this study, the tensile behavior of clay-filled unsaturated orthophthalic polyester composites was evaluated. Specifically, ultimate strength, yield strength, fracture strain, and Young's modulus of two composites with small but varying fractions of clay particulates were determined. Several predictive approaches were considered for correlation with experimental values. Only the Young's modulus of the composites could be predicted satisfactorily. The irregular shape and size distribution of clay particulates seriously complicate attempts to analytically model the mechanical behavior of filled composites. Microcracking response of the composites was evaluated using an acoustic emission (AE) technique. The addition of clay is shown to embrittle the composites and is confirmed by the AE count rate and amplitude distribution data. Scanning electron microscopy of the fracture surface shows evidence of flaw initiated fracture. This study provides an insight into the influence of clay particulates in altering the properties of a polyester matrix.     

A fast and facile microwave irradiation method for the synthesis of ZnO@ZrO2 core-shell nanocomposites and the investigation of their optical properties

ZnO@ZrO₂ core-shell nanocomposites (NCs) were prepared by a novel and accessible path employing microwave (MW) irradiation to regulate photocatalytic property of ZnO. The synthesized ZnO@ZrO₂ NCs were further examined to discern their optical and chemical properties by FT-IR, XPS, XRF, XRD, FE-SEM, EDX, TEM, UV–vis, and PL analysis. XPS data analysis confirmed the presence of zirconium and oxygen on the coated surface. An almost similar zeta potential curve was observed for the pure ZrO₂ and ZrO₂ coated ZnO NCs, predicting the presence of the ZrO₂ layer on ZnO. Photoluminescence studies show the enhanced intensity of ZnO@ZrO₂ nanostructure compared to uncoated ZnO. Photocatalytic activity of ZnO could be controlled by the amorphous ZrO₂ layer, which was guaranteed by the photo mineralization of methylene blue under UV irradiation at room temperature.     

Physicochemical and functional properties of ten cultivars of seem (Lablab purpureus L.), an underexploited bean in Bangladesh

BACKGROUND: Increasing global protein consumption has led to the demand for new sources of food protein, particularly plant sources. Many inexpensive but protein‐rich bean cultivars have not been well evaluated and are thus underutilised. In this study the physicochemical and functional properties of seeds of ten seem cultivars were assessed. RESULTS: In agreement with their sizes, seeds of Airet had the highest 1000‐seed weight and volume, while those of Bari had the lowest. In terms of proximate composition (g kg^?1), protein content ranged from 240.08 (Ashina) to 292.63 (Puti), fat content from 31.47 (Goalgadda) to 38.40 (Puti), ash content from 32.80 (Puli) to 45.53 (Goalgadda) and fibre content from 21.90 (Tatulia) to 28.90 (Noldog). Hydration (g kg^?1) and swelling (mL L^?1) capacities ranged from 1688.60 and 1850.43 (Goalgadda) to 1999.40 and 2208.66 (Rupbhan) respectively. Similarly, cooking time (min) varied from 114 (Rupbhan) to 179 (Goalgadda). Lowest gelation concentration was in the range 80–100 g kg^?1. Water and fat absorption capacities (g kg^?1) ranged from 941.00 and 644.44 (Ashina) to 1043.33 and 749.26 (Puti) respectively. Foaming capacity and stability (mL L^?1) ranged from 443 (Puli) to 635 (Puti) and from 314 (Ashina) to 643 (Rupbhan) respectively. CONCLUSION: Seeds of seem cultivars appear to be a promising food in terms of their protein content and functionality. Copyright © 2009 Society of Chemical Industry     

Optimum Abstraction of Groundwater for Sustaining Groundwater Level and Reducing Irrigation Cost

Adaptation to increasing irrigation cost due to declination of groundwater level is a major challenge in groundwater dependent irrigated region. The objective of this study is to estimate the optimum abstraction of groundwater for irrigation for sustainable management of groundwater resources in Northwest Bangladesh. A data-driven model using a support vector machine (SVM) has been developed to estimate the optimum abstraction of groundwater for irrigation and a multiple-linear regression (MLR)-based model has been developed to estimate the reduction of the irrigation cost due to the elevation of the groundwater level. The application of the SVM model revealed that the groundwater level in the area can be kept within the suction lift of a shallow tube-well by reducing pre-monsoon groundwater-dependent irrigated agriculture by 40%. Adaptive measures, such as reducing the overuse of water for irrigation and rescheduling harvesting, can keep the minimum level of groundwater within the reach of shallow tube-wells by reducing only 10% of groundwater-based irrigated agriculture. The elevation of the groundwater level through those adaptive measures can reduce the irrigation cost by 2.07 × 10³ Bangladesh Taka (BDT) per hectare in Northwest Bangladesh, where the crop production cost is increasing due to the decline of the groundwater level. It is expected that the study would help in policy planning for the sustainable management of groundwater resources in the region.     

Earthquake-related Natech risk assessment using a Bayesian belief network model

Natural hazard triggering technological disasters (Natech) events pose risks to industrial facilities and process plants. As these plants handle hazardous materials, they can endanger nearby residential areas and have financial consequences. Thus, proper Natech risk assessment is required for effective prevention, mitigation and emergency response planning at industrial plants and nearby residential areas. The parameters used to quantify Natech risk assessment are subject to uncertainties and their interactions are non-linear. In this study, a Bayesian belief network-based Natech risk assessment model is developed to assess the earthquake-related Natech risk considering different levels of uncertainties. The cause and effect relationships between different parameters are constructed based on published body of knowledge and expert knowledge. The capabilities of the proposed model are demonstrated for the earthquake-related Natech risk assessment of Kobe City, Higashinada Ward, Japan because of the Great Hanshin earthquake in 1995. The proposed model is also capable of performing both predictive analysis and diagnostic analysis.     

Quantification of high-resolution (1)H NMR spectra from rat brain extracts

Extracting quantitative information about absolute concentrations from high-resolution (1)H NMR spectra of complex mixtures such as brain extracts remains challenging. Partial overlap of resonances complicates integration, whereas simple line fitting algorithms cannot accommodate the spectral complexity of coupled spin systems. Here, it is shown that high-resolution (1)H NMR spectra of rat brain extracts from 11 distinct brain regions can be reproducibly quantified using a basis set of 29 compounds. The basis set is simulated with the density matrix formalism using complete prior knowledge of chemical shifts and scalar couplings. A crucial aspect to obtain reproducible results was the inclusion of a line shape distortion common among all 73 resonances of the 29 compounds. All metabolites could be quantified with <10% and <3% inter- and intrasubject variation, respectively.     

A Robust Bivariate Control Chart Alternative to the Hotelling's T2 Control Chart

In this paper, we proposed a new bivariate control chart denoted by based on the robust estimation as an alternative to the Hotelling's T² control chart. The location vector and the variance‐covariance matrix for the new control chart are obtained using the sample median, the median absolute deviation from the sample median, and the comedian estimator. The performance of the proposed method in detecting outliers is evaluated and compared with the Hotelling's T² method using a Monte‐Carlo simulation study. A numerical example is considered to illustrate the application of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd.