Comment on ‘Thermoelsatic analysis of the functionally graded rotating disk’

In their paper, Hosseini Kordkheili and Naghdabadi (2007) [1] have obtained the Navier thermoelastic equation, along with some coefficients, incorrectly. This has resulted in considerable error in their numerical results. Other authors in this field frequently use the work of Kordkheili and Naghdabadi in their own calculations. Asghari and Ghafoori (2010) [2] is an example of another work that has used the wrong Navier thermoelastic equation directly in their work. It is clear there is a need for corrected formulations, which will be presented here.     

Fourier transform infrared spectroscopic monitoring of sol-gel process in synthesis of PbS-TiO2 hybrid nanostructures

A typical hybrid nanostructure was prepared consisting of lead sulfide (PbS) nano-crystals, embedded in titanium oxide (TiO₂) using sol-gel method. The synthesis procedure was monitored by Fourier transform infrared spectroscopy. Spectroscopic investigations indicated that PbS nano-crystals are embedded in the TiO₂ matrix with no strong Ti-O-Pb-S bonding. The size of PbS hybrid nanostructures decreased with diminishing lead and sulfur mole concentrations. The smallest size of NCs has been obtained in 10% of mole concentration (30-45 nm particle size for the hybrid nanostructure). The morphology and microstructure of the nano hybrid was investigated by scanning electron microscope and X-ray diffraction.     

Analytical calculation of stress intensity factor of cracked steel I-beams with experimental analysis and 3D digital image correlation measurements

An analytical method to calculate the stress intensity factor for cracked steel I-beams under both bending moment and axial load is presented. The method is based on the approach of crack surface widening energy release rate. The crack surface widening energy release rate is formulated by a G^∗-integral and elementary strength theory of materials. Comparisons between the analytical results and results available in the literature for specific cases demonstrate the validity of the methodology. Furthermore, the fatigue and fracture behavior of the steel I-beam are experimentally investigated. The fatigue crack growth rate, residual deflection and stiffness reduction of a cracked beam under cyclic loading are studied. A three-dimensional digital image correlation system is used to illustrate the stress evolution pattern and the plasticity zone around the crack tip using image processing technique, thereby providing further verification of the theoretical models.     

Effects of Puccinellia Distans and Tall Fescue on Modification of C/N Ratios and Microbial Activities in Crude Oil-Contaminated Soils

Abstract

Petroleum contamination of soil is a serious problem throughout oil-producing countries. One of the cost-effective options for removing contaminants from shallow soils is phytoremediation. Vegetation, by stimulating the microorganisms via releasing root exudates near the rhizosphere, may play an important role in the biodegradation of toxic organic chemicals in soil. This experiment investigates the efficiency of this emerging technology following the implementation of five plant species. The study was carried out in a greenhouse using crude oil–contaminated soil from sites around the Tehran Refinery. To study the effect of a water-absorbent agent, we also used hydrogel in this experiment. The microbial population and the C and N content of soil were assessed in the beginning, middle, and the end of the trial. Our findings show that Puccinellia distans and tall fescue could increase microbial population significantly. Hydrogel has a positive impact in this increasing and improved capability of Puccinellia distans for hydrocarbon degradation. C/N ratio for Puccinellia distans treatments decline from 39.57 to 35.     

Experimental and laboratory assessment of clogging potential based on adhesion

Mechanized tunneling through clayey formations is threatened by encountering the clogging problem. Adhesion stress, as the tendency between clay and a metal surface, leads to clogging between TBM and excavated materials. Some empirical clogging classification charts were prepared based on the experienced clogging problems. Moreover, experimental attempts have been made to evaluate clogging potential. The relation between available empirical charts with laboratory measurements has not been fully defined. This research was conducted to clarify the relationship between measured adhesion values and to propose empirical charts to support a laboratory assessment method. In this regard, 35 clayey soil samples (assumed to have different levels of clogging potential) were selected using the main existing empirical evaluation charts. The clayey soil samples were tested at two different consistency indexes using the piston pullout test, as a highly qualified adhesion assessment tool. The performance of available classifications was examined by laboratory test results. For this purpose, distribution of the measured adhesion values and levels of clogging potential with classification charts were compared. Among the examined classification charts, one of them showed a high match with adhesion values. Using the resulting relationship, a new experimental method was proposed to evaluate clogging potential using laboratory data.

     

Assessment of the adhesion potential of kaolinite and montmorillonite using a pull-out test device

Bulletin of Engineering Geology and the Environment - The tendency of clay particles to stick other surfaces means it is adhesive and can cause clogging of tunnel boring machines. Clogging arising...     

Personality patterns among Black, White, and Hispanic combat veterans.

Little is known about racial and ethnic differences in personality pathology in combat veterans. This investigation explored the relationship between race, ethnicity, and personality disorders (PDs) in a sample of 96 combat veterans. Ethnoracial group status was based on self-identification, and the groups were mutually exclusive. PDs were assessed with the MCMI-III, posttraumatic stress disorder (PTSD) was assessed with the Clinician Administered PTSD scale, and combat exposure was assessed with the Combat Exposure Scale. The findings suggest that Hispanic veterans were more likely to have cluster A PDs compared to non-Hispanic veterans, even after controlling for demographics, level of combat exposure, and current PTSD. Implications of the results for the research and treatment of culturally diverse individuals with PDs are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)