Multi-material topology optimization of adhesive backing layers via J-integral and strain energy minimizations

Strong adhesives rely on reduced stress concentrations, often obtained via specific geometry or composition of materials. In many examples in nature and engineering prototypes, the adhesive performance relies on structural rigidity being placed in specific locations. A few design principles have been formulated, based on parametric optimization, while a general design tool is still missing. We propose to use topology optimization to achieve optimal stiffness distribution in a multi-material adhesive backing layer, reducing stress concentration at specified locations. The method involves the minimization of a linear combination of J-integral and strain energy. While the J-integral minimization is aimed at reducing stress concentration, we observe that the combination of these two objectives ultimately provides the best results. We analyze three cases in plane strain conditions, namely (i) double-edged crack and (ii) center crack in tension and (iii) edge crack under shear. Each case evidences a different optimal topology with (i) and (ii) providing similar results. The optimal topology allocates stiffness in regions that are far away from the crack tip, intuitively, but the allocation of softer materials over stiffer ones can be non-trivial. To test our solutions, we plot the contact stress distribution across the interface. In all observed cases, we eliminate the stress singularity at the crack tip. Stress concentrations might arise in locations far away from the crack tip, but the final results are independent of crack size. Our method ultimately provides optimal, flaw tolerant, adhesives where the crack location is known

The Relationship between Psychology and Phenomenology: an analysis based on Husserl’s views

The relationship between an independent scientific discipline called psychology with phenomenology that presents the methodology and method together is an excuse for investigating the relationship between Husserl and Brentano’s thoughts. Although their relationship is come from different sources, according to Husserl’s main problem, end, and concern in confronting psychology, a researcher can find a good issue for research. Psychology and phenomenology bond together in favor of philosophy and seek a different intuition. Husserl keeps a type of psychology and uses it to achieve a philosophical attitude. The difference between Husserl and Brentano is both thematic and methodological, and of course, we can refer to the understanding of others and empathy that reduces the subjective aspect of the experience in Husserl’s phenomenology. Husserl goes to descriptive psychology with criticizing Brentano’s opinion about inner perception and also he criticizes Brentano's psychological reality that is the only appearance for him.  Husserl’s attempt for modifying descriptive psychology makes to provides practical and functional solutions for contemporary psychologists. Of course, he does not forget the distinctions between psychology and phenomenology in terms of issue and method but especially holds them together. The brief article wants to follow the relationship between psychology and phenomenology from its origin (Husserl’s phenomenology) to achieve this purpose, the data of research have been collected through the library method and internet search then they are described and analyzed to reveal the concomitance of psychology and phenomenology. They must come together in the interpretation of the word description

Electrocatalytic determination of cysteine on the multi-wall carbon nanotubes glassy carbon electrode using a homogenous mediator

The electrocatalytic oxidation of cysteine on multi-wall carbon nanotubes glassy carbon electrode (MWCNT-GCE) in phosphate buffer solution in pH (4.0) has been characterized using cyclic voltammetry, chronoamperometry and differential pulse voltammetry. The results showed that the catalytic current of 1,5-bis(3,4-dihydroxy phenyl)penta-1,4-dien-3-one (BPO) depended on the concentration of cysteine. Although cysteine itself showed a very poor electrochemical response at the glassy carbon electrode, the response could be greatly enhanced by using BPO as a mediator, which enabled a sensitive determination of cysteine. The kinetics parameters of this process were calculated, the apparent catalytic rate constant (kÎh) and electron transfer (a) were 867 M-1s-1 and 0.57 respectively. The differential pulse voltammetry response of the modified MWCNT-GCE was linear against the concentration of cysteine in the range 0.5 to 30 μM the limit of detection was found to be 0.17μM

Nanostructured Modified Electrode for Electrocatalytic Determination of Epinephrine in the Presence of Acetaminophen

Abstract In this paper, a nanostructured modified electrode was fabricated by incorporating of 2,2′-[1,9-nonanediylbis(nitriloethylidyne)]-bishydroquinone (NNH) as a newly synthesized modifier and TiO 2 nanoparticles to the carbon paste (MTCPE) and then was used for the electroanalysis of epinephrine (EP). The electrochemical studies were carried out by using cyclic voltammetry, chronoamperometry and differential pulse voltammetry (DPV) techniques. It has been found that the oxidation of EP at the surface of this electrode occurs at a potential about 235 mV less positive than that of an unmodified carbon paste electrode. A dynamic range of 1.0-2000.0 µM, with a detection limit of 0.37 µM for EP, was obtained using DPV. Also, this modified electrode exhibits well separated oxidation peaks for EP and acetaminophen (AC) using DPV. JNS All rights reserve

Investigation of biofilm formation among methicillin-resistant Staphylococcus aureus isolated from children

Background: The aim of the present study was to investigate biofilm formation among Methicillin-resistant Staphylococcus aureus (MRSA) isolated from children referring to a pediatric hospital in Tehran. Methods: In total, 98 MRSA isolates were collected from children referring to a pediatric hospital during 2014 - 2015. All the isolates were confirmed to be MRSA using PCR amplification of the mecA gene. The antibiotic susceptibility patterns of the isolates were determined using the Kirby-Bauer disk-diffusion and E-test methods. In order to assess the ability of biofilm formation among the isolates, Congo red agar (CRA) and Microtiter Plate (Mtp) methods were used. Results: All the isolates were found to be susceptible to linezolid and vancomycin and, likewise, the majority was susceptible to minocycline and rifampicin. CRA and Mtp methods showed that 81.6 and 63.3 of the MRSA isolates, respectively, were biofilm producers. Conclusions: The early identification of S. aureus and detection of biofilm formation by the Mtp method are essential steps towards the prevention of the most serious nosocomial infections. © 2017, Archives of Pediatric Infectious Diseases

Investigation of biofilm formation among methicillin-resistant Staphylococcus aureus isolated from children

Background: The aim of the present study was to investigate biofilm formation among Methicillin-resistant Staphylococcus aureus (MRSA) isolated from children referring to a pediatric hospital in Tehran. Methods: In total, 98 MRSA isolates were collected from children referring to a pediatric hospital during 2014 - 2015. All the isolates were confirmed to be MRSA using PCR amplification of the mecA gene. The antibiotic susceptibility patterns of the isolates were determined using the Kirby-Bauer disk-diffusion and E-test methods. In order to assess the ability of biofilm formation among the isolates, Congo red agar (CRA) and Microtiter Plate (Mtp) methods were used. Results: All the isolates were found to be susceptible to linezolid and vancomycin and, likewise, the majority was susceptible to minocycline and rifampicin. CRA and Mtp methods showed that 81.6 and 63.3 of the MRSA isolates, respectively, were biofilm producers. Conclusions: The early identification of S. aureus and detection of biofilm formation by the Mtp method are essential steps towards the prevention of the most serious nosocomial infections. © 2017, Archives of Pediatric Infectious Diseases

Designing a simple electrochemical method for ozone generation and using for removal of C.I. Reactive blue 203 (RB 203) from textile wastewater

Textile wastewater is one of the most important environmental pollutants. These wastewaters are containing different kinds of dyes, chemicals and salts. Therefore, it is essential to remove these dyes and chemicals from wastewaters before discharging them into the environment. One of the best methods to remove these dyes and chemicals from wastewater is using oxidation agents such as H2O2, O3 and etc. Ozone is an important oxidizing agent which is widely used in the purification of water, wastewater treatment, water disinfection and decomposition of organic materials. The main aim of this study is the investigation of the removal of C. I. Reactive Blue RB 203 as a textile dye from aqueous solutions by using electrochemical ozone generation with a titanium anode electrode modified with a mixture of nickel, antimony and tin oxides. Some parameters such as the pH of the solution, current density and ozonation time were optimized. The textile dye concentration during the degradation process was estimated from the calibration curve (the UV-Vis absorption values versus the dye concentration) and also the kinetic order of the removal of RB 203 was investigated. The results showed that removal of the dye (100 ppm) from the solution increased by increasing ozonation time at a constant current density of 20 mA/cm2 for 40 min electrolysis and also it was removed from solutions with an efficiency of 99%

L-Cysteine determination in embryo cell culture media using Co (II)-phthalocyanine modified disposable screen-printed electrodes

Thiol-containing compounds such as L-cysteine have been demonstrated to play an important role in metabolism and cellular growth, acting as powerful antioxidants. Consequently, their analytical determination in biological media has received a considerable amount of attention. In this work, an electrochemical sensor for the accurate electroanalytical determination of L-cysteine is proposed, based upon a Co(II)-phthalocyanine bulk modified disposable screen-printed graphite electrode (CoPc-SPE). Cyclic (CV) and Square Wave (SWV) voltammetry experiments have demonstrated an excellent electrocatalytic activity towards the electrochemical oxidation of L-cysteine using CoPc-SPEs within optimum neutral or basic pH. Moreover, the SWV response of L-cysteine is found to exhibit a linear range of 2.6–200 μM, with a low limit of detection of 4 μM (S/N = 3) and a sensitivity of 0.78 μA cm− 2 μM− 1. Coefficient of variation for reproducibility and repeatability of L-cysteine determination using the CoPc-SPE are 3 and 0.4%, respectively. The effect of inherent interferences such as naturally occurring amino acids, cystine and cysteic acid has been also evaluated. Finally, the applicability of the L-cysteine electrochemical sensor based upon CoPc-SPEs has been successfully demonstrated for the first time for the assessment of L-cysteine in a complex embryo cell culture medium