38 research outputs found
Shape memory nanocomposite of poly(L-lactic acid)/graphene nanoplatelets triggered by infrared light and thermal heating
Get PDFIn this study, the effect of graphene nanoplatelets (GNPs) on the shape memory properties of poly(L-lactic acid) (PLLA) was studied. In addition to thermal activation, the possibility of infrared actuating of thermo-responsive shape memory PLLA/GNPs nanocomposite was investigated. The incorporated GNPs were expected to absorb infrared wave’s energy and activate shape memory PLLA/GNPs. Different techniques such as differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), field emission gun scanning electron microscope (FEG-SEM) and dynamic mechanical thermal analysis (DMTA) were used to characterize samples. DSC and WAXD results indicated that GNPs augmented crystallinity due to nucleating effect of graphene particles. GNPs improved both thermal and infrared activating shape memory properties along with faster response. Pure shape memory PLLA was slightly responsive to infrared light and its infrared actuated shape recovery ratio was 86% which increased to more than 95% with loading of GNPs. Drastic improvement in the crystallinity was obtained in nanocomposites with lower GNPs contents (0.5 and 1 wt%) due to finer dispersion of graphene which resulted in more prominent mechanical and shape memory properties enhancement. Infrared activated shape memory PLLA/GNPs nanocomposites can be developed for wireless remote shape control of smart medical and bio-systems
Epidermodysplasia verruciformis associated with sensorineural hearing loss in a 9 years old boy
No full textComparison of 40% trichloroacetic acid and cryotherapy for the treatment of plantar warts; a single‐blind, randomized clinical trial
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Thermal, Tensile, Electrical, Dynamic Mechanical Thermal and Rheological Properties of Polyvinylidene Fluoride and Fluoroelastomer Composites Filled with Carbon Black
No full textEffect of Er: YAG Laser Irradiation and Acidulated Phosphate Fluoride Therapy on Re-Mineralization of White Spot Lesions
No full textClinical evaluation of efficacy, safety and tolerability of cysteamine 5% cream in comparison with modified Kligman's formula in subjects with epidermal melasma: A randomized, double-blind clinical trial study
No full textEffect of Er: YAG Laser Irradiation and Acidulated Phosphate Fluoride Therapy on ReMineralization of White Spot Lesions
No full textبررسی آثار آلودگی هوا در میزان مرگ و میر و کاهش امید به زندگی با استفاده از توابع دوز ـ واکنش و اولویتبندی آلایندههای مسئول (مطالعهی موردی: شهر مشهد)
No full textToday, developed and developing countries try to plan the economic, industrial, and urban developments based on environmental protection due to air pollution and its consequences as a global issue. Air pollution as a potential and permanent risk has gradually threatened human health, especially in large cities. Environmental requirements depend highly on management parameters and
play a very important role in the quality of life of citizens. In this study, a series of dose-response functions were applied to analyze the adult mortality due to chronic diseases, the reduced life expectancy as a result of acute and chronic diseases, and the resulting risks for ozone emissions in the city of Mashhad. There are a total of 12 stations in Mashhad which carry out monitoring, measuring, and indexing of the 5 types of pollutants, including CO, , , , and . Information monitored with minimal error, which owned by the year 1393, has been analyzed in this study.One of the main objectives in the field of analysis and monitoring of air pollution is the determination of dominant or responsible pollutant as influential factors. The prioritizing and comparison of air pollutants can offer important contributions as well as create a management view in the allocation of funds in a specified time period. The major air pollutants were prioritized from the point of view of risk using AHP and ELECTRE methods. The results show a maximum amount of 20.8\% in adult mortality and a maximum amount of 8.22 years for men and 8.51 years for women in reduced life expectancy due to chronic diseases which are on the verge of a crisis situation. Statistical
investigation conducted over a period of one year (1393) in the city of Mashhad suggests that the main cause of air pollution is particulate matter less than 2.5 microns (). The results of this research can be used to control pollutants and impose special regulations and restrictions on each contaminant
Heat transfer and flow region characteristics study in a non-annular channel between rotor and stator
No full textThis paper will present the results of the experimental investigation of heat transfer in a non-annular channel between rotor and stator similar to a real generator. Numerous experiments and numerical studies have examined flow and heat transfer characteristics of a fluid in an annulus with a rotating inner cylinder. In the current study, turbulent flow region and heat transfer characteristics have been studied in the air gap between the rotor and stator of a generator. The test rig has been built in a way which shows a very good agreement with the geometry of a real generator. The boundary condition supplies a non-homogenous heat flux through the passing air channel. The experimental devices and data acquisition method are carefully described in the paper. Surface-mounted thermocouples are located on the both stator and rotor surfaces and one slip ring transfers the collected temperature from rotor to the instrument display. The rotational speed of rotor is fixed at three under: 300rpm, 900 rpm and 1500 rpm. Based on these speeds and hydraulic diameter of the air gap, the Reynolds number has been considered in the range: 4000<Rez<30000. Heat transfer and pressure drop coefficients are deduced from the obtained data based on a theoretical investigation and are expressed as a formula containing effective Reynolds number. To confirm the results, a comparison is presented with Gazley’s (1985) data report. The presented method and established correlations can be applied to other electric machines having similar heat flow characteristics
