Optimal characteristics and heat transfer efficiency of SiO2/water nanofluid for application of energy devices: A comprehensive study

In a comprehensive study, the thermal conductivity, dynamic viscosity, and the rheological behavior of a SiO₂/water nanofluid are investigated experimentally at the temperatures, solid concentrations, and the shear rates of 25°C to 50°C, 0% to 1.5%, and 400 to 1400(s^?1), respectively. The Response Surface Methodology (RSM) is utilized to obtain regression models for the thermal conductivity and the dynamic viscosity. Subsequently, the sensitivity of the aforementioned models to 10% changes in the temperature, and the nanofluid concentration is analyzed. Afterward, Nondominated Sorting Genetic Algorithm II (NSGA‐II) is utilized to find the maximum thermal conductivity and the minimum viscosity. The nondominated optimal points are presented through a fitted correlation on a Pareto front to make the results more practical. The measurements of the investigated nanofluid could be summarized as a paper of a handbook. The workability of the investigated nanofluid is also examined in both laminar and turbulent flow regimes through analysis of the heat transfer merit graphs. To this end, the ratio of the dynamic viscosity enhancement to the thermal conductivity enhancement and the Mouromtseff number are chosen as two criteria of the laminar and turbulent flow regimes, respectively. Finally, the results are compared with those for SiO₂/glycerin and SiO₂/ethylene glycol nanofluids to check the workability in different base fluids. From a thermal‐efficiency point of view, the SiO₂/water nanofluid is not suggested for use in both laminar and turbulent pipe flows, except in temperatures higher than 30°C and volume concentrations lower than 1% for the case of laminar flow. This is because the favorable heat transfer enhancement of the nanofluid is more than the unfavorable increase of the pumping power. From the rheological point of view, though, a SiO₂/water nanofluid would be a good choice in lubricating moving surfaces for both laminar and turbulent flow regimes. It is found that in higher nanofluid concentrations, the thermal conductivity of a SiO₂/water nanofluid is highly influenced by temperature. Moreover, adding nanoparticles at temperatures of 35°C to 40°C would have the highest increasing effect on the thermal conductivity. It is also revealed that increasing the temperature does not significantly affect the viscosity when 1% SiO₂ nanoparticles are suspended within the water.     

A contextual approach towards more accurate duplicate bug report detection and ranking

The issue-tracking systems used by software projects contain issues, bugs, or tickets written by a wide variety of bug reporters, with different levels of training and knowledge about the system under development. Typically, reporters lack the skills and/or time to search the issue-tracking system for similar issues already reported. As a result, many reports end up referring to the same issue, which effectively makes the bug-report triaging process time consuming and error prone. Many researchers have approached the bug-deduplication problem using off-the-shelf information-retrieval (IR) tools. In this work, we extend the state of the art by investigating how contextual information about software-quality attributes, software-architecture terms, and system-development topics can be exploited to improve bug deduplication. We demonstrate the effectiveness of our contextual bug-deduplication method at ranking duplicates on the bug repositories of the Android, Eclipse, Mozilla, and OpenOffice software systems. Based on this experience, we conclude that taking into account domain-specific context can improve IR methods for bug deduplication.     

Improvements on approximation algorithms for clustering probabilistic data

Knowledge and Information Systems - Uncertainty about data appears in many real-world applications and an important issue is how to manage, analyze and solve optimization problems over such data....     

Preparation,characterization, and in vitro bioactivity of magnetic co-polymer [N,N-dimethylaminopropylacrylamide-co-1-allylimidazole] as a new nanocarrier for delivery of cefotaxime

In this research, new magnetic nanoparticles (MNPs) conjugated radical co-polymerization with N, N-dimethylaminopropylacrylamide (N, N-DMAPAAm) as a thermosensitive monomer and 1-allylimidazole (AI) as a cross-linker agent was prepared as a magnetic nanocomposite (MNC). The synthesized MNC were characterized by Fourier transform infrared spectroscopy, Elemental analysis (CHN), Field emission scanning electron microscopy, Vibrating Sample Magnetometer, and Thermo Gravimetric Analysis. Cefotaxime was selected as a model drug and was loaded into the synthesized polymer. The main factors of adsorption process such as pH, contact time, temperature, and eluent were evaluated and optimized. The mechanism of cefotaxime adsorption is explained by Langmuir isotherm. Also, in vitro cefotaxime delivery in the simulated gastric and intestinal fluids was investigated. The drug release profile revealed that about 30.35% of the adsorbed cefotaxime was released in the first 30 min. at pH =1.2 (simulated gastric fluid) and 62.65% was released during 15 h at pH =7.4 (simulated intestinal fluid).     

Effects of Al–5Ti–1B on the structure and hardness of a super high strength aluminum alloy produced by strain-induced melt activation process

In this study the effect of Al–5Ti–1B grain refiner on the structural characteristics and hardness of Al–12Zn–3Mg–2.5Cu aluminum alloy has been investigated. The alloy was produced by modified strain-induced melt activation (SIMA) process. Reheating condition to obtain a fine globular microstructure was optimized. The specimens subjected to deformation ratio of 40% (at 300 °C) and various heat treatment times (5–40 min) and temperature (550–620 °C) regimes were characterized in this study. Microstructural study was carried out on the alloy by the use of optical and scanning electron microscopy (SEM) in both unrefined and Ti-refined conditions. The results showed that for the desired microstructures of the alloy during SIMA process, the optimum temperature and time are 575 °C and 20 min respectively. The hardness test results of the alloy also revealed that T6 heat treatment is more effective in hardness enhancement of all specimens in comparison with SIMA processing.     

PROSE treatment of corneal ectasia

PurposeProsthetic replacement of the ocular surface ecosystem (PROSE) uses custom designed and fabricated prosthetic devices in a treatment that restores vision, supports healing, reduces symptoms and improves quality of life in patients with complex corneal disease. We report the success rate for PROSE treatment of corneal ectasia.MethodsRecords of 59 patients with corneal ectasia seen in consultation over 6 months were reviewed. Candidacy for treatment, topographic indices, change in visual acuity, achievement of satisfactory fit, device wear status and change in visual function at 6 months were recorded.ResultsSixteen eyes were non-candidates because conventional correction was adequate. Trial devices were inserted but not dispensed for 13 eyes. No eyes were excluded for severity of ectasia. In the remaining 89 eyes, satisfactory fit was achieved and a device was dispensed. Twenty-one eyes (15 patients) had undergone penetrating keratoplasty. Device wear at 6 months was documented in 78/89 eyes (88%). NEI VFQ-25 score improved 27.6 points (p < 0.001) on a 100 point scale in patients wearing a device at 6 months.ConclusionAll candidate eyes with corneal ectasia could be fitted with a PROSE device. PROSE treatment has a high success rate when measured by ability to achieve satisfactory fit, impact on visual acuity and 6 month data on both rate of continued wear and impact on visual function. PROSE treatment is an alternative to penetrating keratoplasty for patients with corneal ectasia who are contact lens intolerant.     

Enhanced Anti-Tumoral Activity of Methotrexate-Human Serum Albumin Conjugated Nanoparticles by Targeting with Luteinizing Hormone-Releasing Hormone (LHRH) Peptide

Active targeting could increase the efficacy of anticancer drugs. Methotrexate-human serum albumin (MTX-HSA) conjugates, functionalized by luteinizing hormone-releasing hormone (LHRH) as targeting moieties, with the aim of specifically targeting the cancer cells, were prepared. Owing to the high expression of LHRH receptors in many cancer cells as compared to normal cells, LHRH was used as the targeting ligand in this study. LHRH was conjugated to MTX-HSA nanoparticles via a cross-linker. Three types of LHRH targeted nanoparticles with a mean particle size between 120-138 nm were prepared. The cytotoxicity of LHRH targeted and non-targeted nanoparticles were determined on the LHRH positive and negative cell lines. The internalization of the targeted and non-targeted nanoparticles in LHRH receptor positive and negative cells was investigated using flow cytometry analysis and fluorescence microscopy. The cytotoxicity of the LHRH targeted nanoparticles on the LHRH receptor positive cells were significantly more than non-targeted nanoparticles. LHRH targeted nanoparticles were also internalized by LHRH receptor positive cells significantly more than non-targeted nanoparticles. There were no significant differences between the uptake of targeted and non-targeted nanoparticles to the LHRH receptor negative cells. The active targeting procedure using LHRH targeted MTX-HSA nanoparticles could increase the anti-tumoral activity of MTX.