Weigert's effect mechanism observed in dyes

Anisotropic grains have been shown to be spontaneously induced in films that have been oversaturated and overcooled with dye in which Weigert's effect can be observed. Some of the grains exposed to active linearly polarized light are destroyed with the result that the film becomes anisotropic.     

Evaluating the performance of geosynthetic-reinforced unpaved roads using plate load tests

This study evaluates the performance of geosynthetic-reinforced unpaved road sections over soft subgrade using plate load test. The parameters investigated included the location and tensile modulus of geosynthetics, and the number of geosynthetic layers. Stress distribution on top of the subgrade layer and strain distribution along the geosynthetic reinforcements were also investigated. The test results indicated that geosynthetic reinforcement resulted in appreciable reduction of surface deformation and increase of bearing capacity. The test results also demonstrated the effects of geogrid arrangement/location on the performance of unpaved test sections, with double reinforcement location consistently yielded the best improvement. The definite trend of increasing Bearing Capacity Ratio (BCR) and reloading elastic modulus with increasing tensile modulus of geosynthetics was observed when geosynthetics were grouped according to aperture shape and polymer type. The BCR is defined as the ratio of the bearing capacity of reinforced unpaved sections to that of unreinforced unpaved section.     

THERMAL CONDUCTIVITY OF GASEOUS AMMONIA IN THE TEMPERATURE RANGE 358-925 K.

Thermal conductivity of research grade pure ammonia gas has been measured by the column method at pressures of 12.9, 26.5, and 45.0 kN/m² over the temperature range 358 to 925 K. The maximum probable error of measurement is 1.5% at 874 K and it increases in magnitude as the temperature decreases. At 405 K, it is about 4.8%. The experimental data are correlated by the following cubic polynomial in temperature:

k(T)=5.237× 10^-3 + 5.179 × 10^-4 T + 8.404 × 10^-7 T² + 1.557 × 10^-10 T³.

Here k is in mW/cm-K and T is in K.

The experimental values are compared with three kinetic theory expressions for thermal conductivity of polyatomic gases in conjunction with the Stockmayer (12-6-3) potential. It is concluded that none of the theories can accurately predict the thermal conductivity of ammonia and probably of polar gases in general. The diffusion coefficient characterizing the transport of vibrational energy is computed as a function of temperature and on the basis of experimental data and the theory due to Ahtye. It has been long known that the transfer of energy by polyatomic and polar molecules is quite complex because of the presence of internal degrees of freedom and the possibility of resonant energy transfer in the latter (Hirschfelder, Curtiss and Bird, 1964).     

Effect of ethylene carbonate on properties of PVP-CsAlO2-LiClO4 solid polymer electrolytes

ABSTRACT

Solid polymer electrolytes (SPEs) have been widely studied due to its extensive applications in high energy rechargeable batteries, supercapacitors, fuel cells, photoelectrochemical and electrochromic displays. Herein, SPEs based on polyvinyl pyrrolidone (PVP) doped with cesium aluminate (CsAlO₂) nanoparticles (NPs), lithium perchlorate (LiClO₄) as an electrolyte and varying amounts viz., 2, 4, 6 and 8 wt.% of ethylene carbonate (EC) as plasticizer have been fabricated by solution intercalation technique. The structural features of PVP-CsAlO₂-LiClO₄-EC SPEs have been studied by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The morphology of PVP-CsAlO₂-LiClO₄-EC SPEs has been examined by scanning electron microscopy (SEM). The thermal properties of the SPEs were characterized by the thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC) techniques. The TGA and DSC results revealed that a significant reduction in thermal stability and glass transition temperature (T_g) of PVP with an increase in EC content in SPE films. The optoelectrical properties of PVP-CsAlO₂-LiClO₄-EC SPE films have been evaluated using UV–visible spectroscopy. The band gap energy (E_g) was found to decrease with an increase in EC content, exhibiting a minimum of 4.23 eV for PVP-8 wt.% CsAlO₂-15 wt.% LiClO₄-8 wt.% EC. This could be ascribed to the formation of localized states and increased degree of disorder in the PVP-CsAlO₂-LiClO₄ SPE films. The integrated plasticizers increase the values of refractive index (RI), optical conductivity, and dielectric constants of PVP-CsAlO₂-LiClO₄ SPE films. The AC conductivity of the SPEs has been evaluated at room temperature using digital LCR meter in the frequency range 100 Hz – 5 MHz. The conductivity strongly depends on CsAlO₂ NPs and EC plasticizer content in SPEs.     

Selective oxidation of cyclohexane over the bi-functional catalysts Co-MO-TUD-1 (MO = Al2O3, CeO2, NiO,or ZnO)

Journal of Porous Materials - The selective oxidation of cyclohexane was catalyzed by applying a new series of catalytic materials. The new catalytic series consists of two different active sites...     

Novel Nano Structure for Green Energy Harvesting at 10 μm Thermal Radiation

In recent years, the potential of renewable green energy sources has been extensively studied. The proven technology which is photovoltaic solar cells strictly depends on daylight and produces low-efficiently. To overcome the restrictions, one technology studied is through harvesting the thermal radiation energy which can provide a 24-hour energy source. The continuity of energy sources promises very good energy conversion especially for military applications. This article presents a new structure that can harvest the abundant thermal radiation energy into usable energy at the wavelength of 10 m. A rectangular structure with a perturbation slit was designed to integrate with a rectifier circuit for green energy conversion. The slit tunnel junction guided the electromagnetic field into a junction where the energy could be collected and converted. An enhancement factor of approximately 110.6 can be achieved by a perturbation slit length of 1.0 m. The results extracted from the proposed design promise a better candidate to overcome the disadvantages of photovoltaic solar cells for energy harvesting devices.     

Measurement of functional impairments in human locomotion using pattern analysis

The authors have developed a measurement methodology for the efficient and reliable analysis of human gait dynamics at a level that quantifies variations from morphometrically adjusted normal in three dimensions and in real-time. The large quantities of acquired kinetic, kinematic and electromyographic data are dealt with as aggregate information granules, enabling an efficient partition of input space and more rapid analysis. The process of data aggregation or granulation is predicted on an understanding and application of the functional relationships of human movement and are expressed in an implication table. This implication table is the basis of a fuzzy relational matrix, a feature pattern, established between the dynamic activities during locomotion.The performance and efficiency of the system have been evaluated using two case studies of gait impairments involving two patients each with cerebral palsy and with multiple sclerosis, respectively.     

Mechanistic–empirical analysis of the results of finite element analysis on flexible pavement with geogrid base reinforcement

A finite-element response model was developed using ABAQUS software package to investigate the effect of geogrid base reinforcement on the response of a flexible pavement structure. Finite-element analyses were then conducted on different unreinforced and geogrid-reinforced flexible pavement sections. In this analysis, the base course (BC) layer was modelled using an elasto-plastic bounding surface model. The results of the finite-element analyses showed that the geogrid reinforcement reduced the lateral strains within the BC and subgrade layers, the vertical strain and shear strain at top of subgrade, and the surface permanent deformation. The higher tensile modulus geogrid resulted in larger reduction of surface permanent deformation. Based on the response parameters computed from the finite element analysis, the improvement of using geogrid for BC reinforcement was then evaluated using the damage models for rutting in the mechanistic–empirical method developed through NCHRP Project 1-37a. The results of mechanistic–empirical analyses showed that the traffic benefit ratio values can reach as high as 3.7 for thin base pavement section built over weak subgrade using high tensile modulus geogrid.