Localized radiative energy transfer from a plasmonic bow-tie nanoantenna to a magnetic thin film stack

Localized radiative energy transfer from a near-field emitter to a magnetic thin film structure is investigated. A magnetic thin film stack is placed in the near-field of the plasmonic nanoantenna to utilize the evanescent mode coupling between the nanoantenna and magnetic thin film stack. A bow-tie nano-optical antenna is excited with a tightly focused beam of light to improve near-field radiative energy transfer from the antenna to the magnetic thin film structure. A tightly focused incident optical beam with a wide angular spectrum is formulated using Richards-Wolf vector field equations. Radiative energy transfer is investigated using a frequency domain 3-D finite element method solution of Maxwell’s equations. Localized radiative energy transfer between the near-field emitter and the magnetic thin film structure is quantified for a given optical laser power at various distances between the near-field emitter and magnetic thin film

Pressure drop across micro-pin heat sinks under boiling conditions

Two-phase pressure drop was studied in four different micro pin fin heat sinks. Micro pin fin heat sinks used in the current studies were operated under boiling conditions using water and R-123 as working fluids. It was observed that once boiling was initiated severe temperature fluctuations and flow oscillations were recorded for three of the micro pin fin heat sinks, which was characterized as unstable boiling. Pressure drop signals were presented just before and after the unstable boiling conditions. Flow images and FFT (fast Fourier Transform) profiles of pressure signals were used to explain experimental results and unstable nature in flow boiling observed in the three of the devices. Stable boiling conditions where the temperature and pressure drop had a steady and stable profile could be only obtained from one micro pin fin heat sink at high mass velocities. The two-phase pressure drop in this hydrofoil-based micro pin fin heat sink has been investigated using R-123 as the working fluid. Two-phase frictional multipliers have been obtained over mass fluxes from 976 to 2349 kg/m2. It has been found that the two-phase frictional multiplier is strongly dependent on flow pattern. The theoretical prediction using Martinelli parameter based on the laminar fluid and laminar gas flow represented the experimental data fairly well for the spray-annular flow. For the bubbly and wavy-intermittent flow, however, large deviations from the experimental data were recorded. The Martinelli parameter was used successfully to determine the flow patterns, which were bubbly, wavy-intermittent, and spray-annular flow in the current study

Assessment of Asthma Control and Severity among Children According to Global Initiative for Asthma Guidelines in Sulaimani City-Iraq

Background: Asthma is a common and potentially serious chronic disease that imposes a substantial burden on patients, their families and the community. Objective: Assessment of the level of asthma control and severity in asthmatic children in Sulaimani city according to the global initiative for asthma (GINA) guidelines. Methods: A cross-sectional study of 82 patients who are known cases of asthma, aged 5 – 15 years , from 1st of March 2014 to 1st of August 2014. Results: Out of 82 patients in our study, 20.8%were classified as having intermittent asthma all of them have well controlled asthma, 42.7% of those classified as having mild persistent asthma 65.7% of them have well controlled asthma, 26.8% of those classified as having moderate persistent asthma 54.5% of them have partly controlled asthma, and 9.8%of those classified as having severe persistent asthma the majority of them 87.5% have uncontrolled asthma and none of them reached to the controlled asthma level according to GINA guidelines. Regarding the peak expiratory flow (PFT) we notice that 58.8% of asthmatic children who were classified as having intermittent severity, their PEF measurements ranged between 160- 250 l/min while those with severe persistent asthma 75% of them have readings between 50-150 l/min. Conclusion: Current levels of asthma control in the Sulaimani city fall far short of the goals specified in the GINA guidelines for asthma management. Also there is a strong correlation between PEF measurements and the level of asthma severity

Thermoelectric-coupled hydrodynamic cavitation energy harvesting system

The ever growing energy demand has led to the advent of different energy harvesting systems. This study investigates the performance of a thermoelectric coupled hydrodynamic cavitation system as an energy harvesting device. The effect of changing the working fluid from water to Titania-water nanofluid on the heat generation of the cavitation system is discussed in this study and also the coupling of the cavitation system with one of the micro thermoelectric generators in the literature is included. At the end, the device performance is quantified by comparing its power generation with the required power for the daily used miniature electrical devices

Changing bubble dynamics in subcooled boiling with TiO₂ nanoparticles on a platinum wire

Bubble dynamics in pool boiling provides a suitable platform for researchers to understand the mechanisms of subcooled boiling heat transfer. Besides, the effects of nanoparticles on this phenomenon have not been fully understood yet. In this study, the effect of TiO2 nanoparticles (with two weight fractions, 0.002% and 0.005%) mixed in de-ionized water during subcooled pool boiling on a thin platinum wire with a diameter of 250 μm was experimentally investigated for working bulk fluid temperatures between 30 and 50 °C at atmospheric pressure, and new bubble dynamics phenomena were reported. Applied heat fluxes varied from onset of nucleate boiling point to higher heat fluxes up to nucleation jet flow. The experiments were visualized with a high speed camera system, and acquired videos and images were utilized for analysing prevalent phenomena, such as bubble-bubble and nucleation site-bubble interactions, surface tension and Marangoni convection, structural disjoining pressure, pinning and nanoparticles deposition effects as well as the main mechanisms. In general, migration, coalescence, leaping and detaching were recorded for nanofluids with weight fractions of 0.002 wt% and 0.005 wt%, while oscillation, dancing and stick processes were exclusively observed only in nanofluids with a weight fraction of 0.005 wt%. The images, results, and related discussion provide new knowledge and physics for pool boiling phenomena on platinum fine wires in the presence of nanoparticles

Knowledge, Attitude and Performance Associated with Disaster Preparedness in Iranian Nurses: A Systematic Review and Meta-analysis

Context: Nurses are the largest group of health service providers with a vital role in assisting victims during disasters. They must be therefore appropriately prepared to respond to health requirements in these situations. Evidence acquisition: Three articles were ultimately extracted from a comprehensive search conducted in the present systematic review and meta-analysis in Google Scholar, SID, Magiran, Scopus, PubMed and Web of Science using English keywords and their Persian equivalents. The I2 index was used to evaluate the heterogeneity between the studies, and the analyses were performed in STATA 14. Results: This review was conducted on 586 nurses working in hospitals. The final meta-analysis included three articles. The matched mean scores of knowledge, attitude and performance concerning disaster preparedness were respectively found to be 43.49 (95% CI: 37.67-49.31, P=0.581, I2=0.0%), 68.81 (95% CI: 63.04-70.58, p=0.913, I2=0.0%) and 56.19 (95% CI: 53.95-58.42, P=0.001, I2=86.2%). Conclusion: The present findings suggested moderate levels of knowledge and performance and good attitudes associated with preparedness in disasters in the Iranian nurses. These parameters can be therefore improved to desirable levels and the overall preparedness for coping with disasters boosted in nurses by training nurses and performing hospital drills

Cytotoxicity assessment of Labisia pumila on prostate cancer cell lines (DU145)

Labisia pumila or locally known as Kacip Fatimah devours the great prospective in the herbal industry. This herbaceous undershrub of the Myrsinaceae family has been used a long time ago and has been exploited aggressively as drinks, cosmetics and health supplement There are three varieties of L pumila, which is L pumila var alata, L pumila var pumila and L pumila var lanceolata and each has their own use and properties. It is believed that L pumila var alata may demonstrate some anticancer activities exerted by certain phytochemical abundant such as gallic acid in this plant. The leaves of L pumila var alata were extracted using three different types of extraction which are maceration, direct and indirect ultrasound assisted extraction. Water was used as the solvent for each type of extraction. MTT, viability test and morphological studies were carried out to determine the cytotoxicity effects of three types of plant extracts on human prostate cancer cell tines (DU 145). The phenolic compound such as gallic acid, kaemferol and caffeic was detected via HPLC. The MTT assay indicated that plant extracts from maceration induce apoptosis and inhibit around 42% of the cell population compare to negative controls. In case of viability studies, maceration extracts have killed a!! the cells within 9 days white the negative control recorded 12 days for alt cells to die. The morphological changes were observed using an inverted microscope to perceive the irregular detachment and clumping of the cells. There was some morphological changing of the cells from hexagonal to round shape after treatment with the extracts. Blabbing cells, chromatin condensation, apoptotic cells and late apoptotic body can be seen after staining. As conclusion, L pumila shows the significant inhibition of growth of prostate cancer cell tines and can be applied as cytotoxic agents in the future treatment of prostate cancer

COVID-19: Features, clinical course and concerns

The coronavirus disease 2019 (COVID-19) was first detected in December 2019 in Wuhan, China . So far, 136 reports from the WHO were reported. In the latest report, 6416828 patients in almost all countries have been infected with the COVID-19. The present study discusses the different aspects of COVID such as emergence, signs and symptoms, comparisons with SARS and MERS, concerns, governments' actions in controlling the virus and a descriptive analysis of the spread and death. The emergence of the coronavirus family in the last two decades has created a public health issue around the world. It has also caused serious damages to infrastructure, economy, culture and communities of countries. Thus, affected governments have taken steps to reduce these concerns such as quarantine, education, traffic control, closure of recreational centers, reduction of working hours etc. Despite strict measures to contain the COVID-19, this virus is still expanding and the question of "what actions should be taken with what political package?" is being asked. To answer this question, it is important to understand the process of disease occurrence and modeling different interventions on changing the natural course of the disease is very importan

Investigation of Single Air Bubble Dynamics and the Effect of Nanoparticles in Rectangular Minichannels

Bubble dynamics and understanding related mechanisms based on force analysis are necessary for better understanding two-phase flow phenomena in small channels. To address this subject, experiments were conducted with injected single air bubbles into rectangular minichannels containing flows of pure water, pure ethanol and TiO2-nanoparticle-based nanofluids, which had a nanoparticle mass fraction of 0.005 wt% for both water and ethanol base fluids. For a range of fluid flow rates, bubble movement and temperature profiles were captured along the channel using high-speed and infrared (IR) cameras, respectively. Upon heating, when using nanofluids, deposition of TiO2 nanoparticles occurred. The results in the channels with cross sectional dimensions of 2 mm × 4 mm and heated length of 7 cm were compared with their counterparts on plain surfaces. Heat fluxes were applied by means of a tantalum film heater on the outer surface of the channel. Bubble dynamics and forces acting on the bubbles were quantitatively analyzed in relation to the fluid type, heat flux, flow rate and deposition. This study highlights the effects of TiO2-nanoparticles (dispersed in two different base fluids) on single-bubble dynamics in minichannels. The nanoparticle deposition was found to have a retarding effect on the bubble movement and led to a more elliptical shape rather than a spherical bubble shape. The bubble behavior is comprehensively assessed in the light of the visualization data and acting forces