Understanding the charge transfer and defect states in ZnO/In2O3 composite nanostructures (CNs)

Journal of Materials Science: Materials in Electronics - This report presents the VLS synthesis and the study of the charge carrier transport through defect states across the interface in ZnO/In2O3...     

Effect of alumina content and heat treatment on microstructure and upconversion emission of Er3+ions in oxyfluoride glass-ceramics

The effect of alumina content and heat treatment temperature and time, on microstructure and Er3+ (0.5 mol.%) emission of oxy-fluoride glass-ceramics were investigated in this research. Two values of 1.8 (SA1.8Er0.5) and 2.18 (SA2.18Er0.5) were selected in this re-search for SiO2/Al2O3 ratio. According to DTA results, precursor glasses were heat treated at 630, 660 and 690 °C for 4 h and some glasses were also heat treated at 630 °C for 48 and 72 h. The results indicated that alumina content had significant effect on phase separation and vis-cosity of the glasses. Therefore the size, size distribution, and volume concentration of nano CaF2 crystals which precipitated during the heat treatment depended on alumina content of the glass. Due to the much smaller size of the precipitated CaF2 crystals in the glasses of low alumina content, these samples maintained excellent transparency and had narrower crystal size distribution than the high alumina glasses. The crystal size was increased markedly with the temperature increasing from 630 to 690 °C. On the other hand a slight increase was observed in the crystal size by raising the heat treatment time in both glasses. Results indicated that in low alumina content glass (SA2.18Er0.5) the size of CaF2 nanocrystals was controlled in one order of magnitude. The increase of heat treatment time and temperature led to the incorporation of Er3+ ions into CaF2 crystalline phase, increasing significantly the upconversion intensity. After heat treatment at 690 ℃ for 4 h, atomic force microscope (AFM) re-vealed the development of small crystals with an average size of 80 and 30 nm in SA1.8Er0.5 and SA2.18Er0.5 samples, respectively.     

Change Point Estimation Methods for Control Chart Postsignal Diagnostics: A Literature Review

Control charts are the most popular monitoring tools used to distinguish between special (assignable) and common causes of variation and to detect any changes in processes. The time that a control chart gives an out‐of‐control signal is not the real time of change. The actual time of the change is called the change point. Knowing the real time of the change will help and simplify finding the assignable causes of the signal, which may be the result of a shift in the process mean or change in process variability. This article gives an overview of change point estimation in control charts, provides a classification scheme, and describes the research that has previously appeared in the literature. In addition, a gap analysis in this area provides direction for future research. Copyright © 2011 John Wiley & Sons, Ltd.     

Surfactant-assistant solvo/hydrothermal methods for preparation of nanoscale calcium aminodiphosphonates exhibiting high methylene blue adsorption affinity

Using surfactant-assistant solvo/hydrothermal methods, nanoscale calcium aminodiphosphonate species (CadP) with different morphologies, namely nanobelts, nanorods, and nano-networks have been synthesized. The final products with various morphologies have been obtained through controlled experimental conditions such as type of surfactant (with different concentrations), solvent, and base. Selected samples have been characterized by elemental analysis, FT-IR, TGA, XRD, SEM and TEM. Removal of a cationic/basic dye (methylene blue) from aqueous solution was investigated using synthesized nano-networks (CadP-N) as adsorbents. Effects of process parameters such as adsorbent morphology, adsorbent dose, pH, contact time, and initial dye concentration on the extent of methylene blue (MB) adsorption were investigated. Both the Langmuir and the Freundlich isotherms are fit to explain the MB adsorption on CadP-N. The maximum adsorption capacity of CadP-N was found to be 138.89 mg/g. Desorption experiments showed that CadP-N has the ability to remove adsorptive on the MB treatment for recycling use.     

One-Dimensional Quantum Compass Model in an Out-plane Magnetic Field

The one-dimensional quantum compass model (1D-QCM) in an out-plane magnetic field is investigated by numerical and analytical methods. The presence of the 1D-QCM in an area of the ground-state magnetic phase diagram where the odd couplings are antiferromagnetic and larger than the even couplings is studied. Using pseudo spin ladder operators indicates that the 1D-QCM in an out-plane magnetic field can be mapped to the one-dimensional Ising model in a transverse magnetic field (ITF). Analytical investigation of the effective ITF Hamiltonian predicts the occurrence of two quantum phase transitions with increasing magnetic field. Also, the critical fields are obtained from this method, which are completely in agreement with the results of the numerical experiment based on the Lanczos method. This numerical method accurately determined the behavior of the energy gap, magnetization and string order parameter, and therefore it is a very useful method for indicating the ground-state phases of the system.     

Investigation of tensile properties and dyeing behavior of various polypropylene/amine modifier blends

Polypropylene is utilized in manifold applications due to its unique properties. However, its use has been limited in the textile industry because conventional dyestuffs have no affinity for this polymer. Amine modifiers, generally improve the dye‐ability of polypropylene. Polyamide 6 (PA6) is a traditional amine modifier which improves the dyeing ability of polypropylene with disperse dyes. In this investigation, polyetheramine (PEA) is introduced as a novel amine modifier which improves the dye‐ability of polypropylene with disperse and acid dyestuffs. To this end, the dyeing behavior as well as possible impairments of tensile properties of PEA modified polypropylene were studied and compared to PA6 modified polypropylene. As with the PA6 containing blends, the tensile properties of the incompatible PP/PEA blends decreased due to weak interfacial adhesions between the components of the blends. However, the incorporation of a compatibilizer into such blends led to better dispersions of modifiers in the matrix as well as formation of amide or imide linkages which in turn reincreased the tensile properties almost to their initial values. Both PEA and PA6 modifiers improved the disperse dye uptake of the blends. However, Only Jeffamine ED‐2003 (i.e., PEA) was capable of enhance the acid dye uptake of modified polypropylene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Bearing capacity of strip footings on sand slopes reinforced with geogrid and grid-anchor

This paper presents the effect of a new type of geogrid inclusion on the bearing capacity of a rigid strip footing constructed on a sand slope. A broad series of conditions, including unreinforced cases, was tested by varying parameters such as geogrid type, number of geogrid layers, vertical spacing and depth to topmost layer of geogrid. The results were then analyzed to find both qualitative and quantitative relationships between the bearing capacity and the geogrid parameters. A series of finite element analyses was additionally carried out on a prototype slope and the results were compared with the findings from the laboratory model tests and to complete the results of the model tests. The results show that the bearing capacity of rigid strip footings on sloping ground can be intensively increased by the inclusion of grid-anchor layers in the ground, and that the magnitude of bearing capacity increase depends greatly on the geogrid distribution. It is also shown that the load-settlement behavior and bearing capacity of the rigid footing can be considerably improved by the inclusion of a reinforcing layer at the appropriate location in the fill slope. The agreement between observed and computed results is found to be reasonably good in terms of load-settlement behavior and optimum parameters.     

Courtyard design impact on indoor thermal comfort and utility costs for residential households: Comparative analysis and deep-learning predictive model

A courtyard is an architectural design element which is often known as microclimate modifiers and is responsible to increase the indoor occupant comfort in traditional architecture. The aim of this study is to conduct a parametric evaluation of courtyard design variants in a residential building of different climates with a focus on indoor thermal comfort and utility costs. A brute-force approach is applied to generate a wide range of design alternatives and the simulation workflow is conducted by Grasshopper together with the environmental plugins Ladybug and Honeybee. The main study objective is the evaluation of the occupant thermal comfort in an air-conditioned residential building, energy load, and cost analysis, derived from different design variables including courtyard geometry, window-to-wall ratio, envelope materials, heating, and cooling set-point dead-bands, and building geographical location. Furthermore, a Deep Learning model is developed using the inputs and outputs of the simulation and analysis to transform the outcomes into the algorithmic and tangible environment feasible for predictive applications. The results suggest that regarding the thermal loads, costs, and indoor thermal comfort index (PMV), there are high correlations between the outdoor weather variation and dead-band ranges, while in extreme climates such as Singapore, courtyard spaces might not be efficient enough as expected. Finally, the highly accurate deep learning model is also developed, delivering superior predictive capabilities for the thermal comfort and utility costs of the courtyard designs.     

Bird strike analysis on a typical helicopter windshield with different lay-ups

In the current paper, bird strike to a typical helicopter windshield is investigated using smoothed particles hydrodynamic (SPH) finite element method. Five types of lay-ups in a windshield (single layer stretch acrylic, single layer glass, two-wall cast acrylic, acrylic with Polyvinyl butyral (PVB) interlayer and glass with PVB interlayer) is considered and in each case the thickness which prevents the bird from perforating the windshield is calculated. Since helicopters can have lateral movement in addition to their longitudinal movement, the effect of incident angle on the integrity of windshield is also investigated. Simulations showed that among the five cases presented, glass with PVB interlayer can be the best choice for being used in windshield against bird strike. Another conclusion is that for the same initial velocity, the angled impact can cause more damage in the windshield than the direct impact.     

A fuzzy multi-objective programming model for supplier selection with volume discount and risk criteria

In contemporary supply chain management, the performance of potential suppliers is evaluated against multiple criteria. In this paper, a fuzzy multi-objective programming model is outlined to propose supplier selection taking quantitative, qualitative, and risk factors into consideration. Also quantity discount has been considered to determine the best suppliers and to place the optimal order quantities among them. The mixed integer derivative nonlinear programming is obtained from fuzzy multi-objective programming model by chance-constrained method. To solve this problem, an innovative method is proposed. In addition, several “what if” scenarios are facilitated. Finally, a real-life sample is used to validate the proposed model.