Experimental investigation on stability of an elastically mounted circular tube under cross flow in normal triangular arrangement

Experimental investigation on flow perturbations coupled with tube vibrations along the interstitial flow path are presented. A Normal Triangular tube arrays at different operating conditions with a pitch ratio of 1.85 was calculated. Interstitial flow perturbations Measurements all along the flow path were recorded by means of a hot-wire probe while monitoring the tube vibration in the stream wise and cross flow directions. A single flexible tube located in the centre of a rigid array was equipped with pressure transducers to observe the surface pressure deviation. The amplitude of flow perturbation and phase with respect to the tube vibrations were acquired at a number of positions alongside the flow path in the array. The consequence of tube vibration amplitude, mean gap velocity frequency, and measurement position of the hot wire probe on the amplitude of the flow perturbation and comparative phase were examined. It is observed that the perturbations of the fluid flow are primarily evident at the position of separation of the fluid flow from the test tube and decay swiftly with space from this position. It shows that the time delay between tube vibration and perturbation of the flow is associated with separation of the flow and enhanced vortices resulted due to the tube vibration

Reduction of Silver Ions by Cell Free Extracts of Westiellopsis

Biosynthesis of silver nanoparticles using Westiellopsis sp. (A15), a filamentous cyanobacterium belonging to the family Fischerellaceae, has been demonstrated. Aqueous silver ions (Ag+) when exposed to the culture filtrate of Westiellopsis were reduced in the solution, which were characterized by biophysical measures utilizing the UV-Vis spectroscopy, scanning electron microscopy (SEM), and FTIR. The nanoparticles exhibited the maximum absorbance at 420 nm in UV-Vis spectroscopy, while the SEM micrograph revealed that the aggregated nanoparticles vary in size between 20 nm and 5 µm. However, the FTIR analysis provided evidence for presence of proteins in the filtrate to be involved in the reduction of silver ions

Evaluation of doctors’ performance as facilitators in basic medical science lecture classes in a new Malaysian medical school

Background: Didactic lecture is the oldest and most commonly used method of teaching. In addition, it is considered one of the most efficient ways to disseminate theories, ideas, and facts. Many critics feel that lectures are an obsolete method to use when students need to perform hands-on activities, which is an everyday need in the study of medicine. This study evaluates students’ perceptions regarding lecture quality in a new medical school. Methods: This was a cross-sectional study conducted of the medical students of Universiti Sultan Zainal Abidin. The study population was 468 preclinical medical students from years 1 and 2 of academic year 2012–2013. Data were collected using a validated instrument. There were six different sections of questions using a 5-point Likert scale. The data were then compiled and analyzed, using SPSS version 20. Results: The response rate was 73%. Among 341 respondents, 30% were male and 70% were female. Eighty-five percent of respondents agree or strongly agree that the lectures had met the criteria with regard to organization of lecture materials. Similarly, 97% of students agree or strongly agree that lecturers maintained adequate voices and gestures. Conclusion: Medical students are quite satisfied with the lecture classes and the lectures. However, further research is required to identify student-centered teaching and learning methods to promote active learning

Salvinorin A Regulates Dopamine Transporter Function Via A Kappa Opioid Receptor and ERK1/2-Dependent Mechanism

Salvinorin A (SalA), a selective κ-opioid receptor (KOR) agonist, produces dysphoria and pro-depressant like effects. These actions have been attributed to inhibition of striatal dopamine release. The dopamine transporter (DAT) regulates dopamine transmission via uptake of released neurotransmitter. KORs are apposed to DAT in dopamine nerve terminals suggesting an additional target by which SalA modulates dopamine transmission. SalA produced a concentration-dependent, nor-binaltorphimine (BNI)- and pertussis toxin-sensitive increase of ASP+ accumulation in EM4 cells coexpressing myc-KOR and YFP-DAT, using live cell imaging and the fluorescent monoamine transporter substrate, trans 4-(4-(dimethylamino)-styryl)-N-methylpyridinium) (ASP+). Other KOR agonists also increased DAT activity that was abolished by BNI pretreatment. While SalA increased DAT activity, SalA treatment decreased serotonin transporter (SERT) activity and had no effect on norepinephrine transporter (NET) activity. In striatum, SalA increased the Vmax for DAT mediated DA transport and DAT surface expression. SalA up-regulation of DAT function is mediated by KOR activation and the KOR-linked extracellular signal regulated kinase-½ (ERK1/2) pathway. Co-immunoprecipitation and BRET studies revealed that DAT and KOR exist in a complex. In live cells, DAT and KOR exhibited robust FRET signals under basal conditions. SalA exposure caused a rapid and significant increase of the FRET signal. This suggests that the formation of KOR and DAT complexes is promoted in response to KOR activation. Together, these data suggest that enhanced DA transport and decreased DA release resulting in decreased dopamine signaling may contribute to the dysphoric and pro-depressant like effects of SalA and other KOR agonists

Tungsten heavy alloys with molybdenum, Y₂O₃ and lanthanum. A review

The consolidated results of studies of tungsten doping with various metals and compounds (Ni, Fe, Cu, Mo, Y₂O₃, La₂O₃) are presented, the advantages of doping with regard to its conditions, microwave and plasma sintering techniques are shown. It has been found that the mechanical properties of tungsten are significantly improved by the addition of the above elements. The resulting heavy fame tungsten can be used to protect against nuclear radiationПредставлено консолідовані результати досліджень легування вольфраму різними металами і сполуками (Ni, Fe, Cu, Mo, Y₂O₃, La₂O₃), показано переваги легування з урахуванням його умов, техніки мікрохвильового і плазмового спікання. Виявлено, що механічні властивості вольфраму значно покращилися при додаванні вищевказаних елементів. Отримані важкі слави вольфраму можуть бути використані для захисту від ядерного випромінювання.Представлены консолидированые результаты исследований легирования вольфрама различными металлами и соединениями (Ni, Fe, Cu, Mo, Y₂O₃, La₂O₃), показаны преимущества легирования с учетом его условий, техники микроволнового и плазменного спекания. Обнаружено, что механические свойства вольфрама значительно улучшились при добавлении вышеуказанных элементов. Полученные тяжелые славы вольфрама могут быть использованы для защиты от ядерного излучения

Characterization and tribological analysis on AA 6061 reinforced with AlN and ZrB2 in situ composites

This research paper deals with AA 6061 composite material with various amounts of weight percentage (wt%) of reinforcements of aluminium nitride (AlN) and zirconium boride (ZrB2). The various amounts of reinforcements like 0 wt%, 3 wt%, 6 wt%, 9 wt% and 12 wt% were mixed with matrix by in situ method of stir casting. Then, the mechanical properties like hardness, tensile and compressive strengths were analyzed as per ASTM standards. The microstructure shows the particle distribution and dispersion within the composites and X-ray diffraction (XRD), energy dispersive spectrograph (EDS) analyzed the constituents of AA 6061 composites. The wear resistance is examined by pin on disc method with various input parameters like composites (wt%), Load (N) and Velocity (m/s). The wear rate (mm3/m) was calculated for each wt% of reinforcements by mass loss (g). The SEM examination was conducted before and after the wearing of AA composites to study the consequent worn surfaces and defects. The optimization techniques like Taguchi and ANOVA were then applied to obtain the best processing parameter and most significant parameter of the AA 6061 composites. The theoretical and optimization results were compared for identifying the best results with GA. Keywords: Aluminium matrix composites (AMC), Particle reinforcements, Mechanical properties, Metallurgical properties, Tribology and optimization technique

Neuromorphic vision: From sensors to event-based algorithms

Regardless of the marvels brought by the conventional frame-based cameras, they have significant drawbacks due to their redundancy in data and temporal latency. This causes problem in applications where low-latency transmission and high-speed processing are mandatory. Proceeding along this line of thought, the neurobiological principles of the biological retina have been adapted to accomplish data sparsity and high dynamic range at the pixel level. These bio-inspired neuromorphic vision sensors alleviate the more serious bottleneck of data redundancy by responding to changes in illumination rather than to illumination itself. This paper reviews in brief one such representative of neuromorphic sensors, the activity-driven event-based vision sensor, which mimics human eyes. Spatio-temporal encoding of event data permits incorporation of time correlation in addition to spatial correlation in vision processing, which enables more robustness. Henceforth, the conventional vision algorithms have to be reformulated to adapt to this new generation vision sensor data. It involves design of algorithms for sparse, asynchronous, and accurately timed information. Theories and new researches have begun emerging recently in the domain of event-based vision. The necessity to compile the vision research carried out in this sensor domain has turned out to be considerably more essential. Towards this, this paper reviews the state-of-the-art event-based vision algorithms by categorizing them into three major vision applications, object detection/recognition, object tracking, localization and mapping. This article is categorized under: Technologies > Machine Learnin