The bacteriological assessment of urine in patients with premature rupture of membranes

Background: PROM occurs in 10% of all pregnancies. Urinary tract infections (UTIs) are the most common bacterial infections in pregnancy. Asymptomatic bacteriuria (ASB), occurring in 2-11% of pregnancies, is a significant predisposition to the development of pyelonephritis and UTI, which are associated with obstetrical complications, such as preterm labor and low birth weight infants. Methods: This study was carried out at the Department of Obstetrics and Gynaecology, Mymensingh Medical College Hospital, Mymensingh, Bangladesh, over a period of 6 Months from July 2011 to December 2011. Results: A total of 100 patients of PROM were included in this study within this period. The mean age was 27.10±4.49 (SD) years in patients’ of PROM, and the prevalence of gestational week was found at 26 (26%) at 30 weeks, 20 (20%) at 32 weeks, 22 (22%) at 33 weeks, 28 (28%) were at 34 weeks, and 4 (4%) were at 39 weeks. Most of the cases were no growth (84%), E. coli (12%), Streptococcus (2%), Candida (1%), and anaerobs (1%). 52% were preterm, and 42% were term delivery. 40% developed chorioamnionitis, 10% developed puerperal sepsis, and 8% developed DIC, and this prospective observational study revealed that 16% of cases of PROM patients’ were associated with urinary tract infection. Conclusions: This study was undertaken to determine the bacteriological assessment of urine of patient’s with premature rupture of membrane. It is found that 16% of patients’ with PROM have urinary tract infection with E. coli, Group B streptococcus, anaerobs, and candida organisms

Is metal nanofluid reliable as heat carrier?

Abstract not availableJ. Nine, Hanshik Chung, Riyad Tanshen, N.A.B. Abu Osman, Hyomin Jeon

Analysis of pressure fluctuations to evaluate thermal performance of oscillating heat pipe

The oscillations of liquid slugs and vapor plugs inside an oscillating heat pipe (OHP) are captured and shown in terms of pressure frequency spectrum. Pressure fluctuation inside a single loop OHP between the evaporative and the condensing sections is analyzed to evaluate thermal performance. De-Ionized (DI) water and Cu/water nanofluid with different mass fractions (0.5wt%, 1wt%, 2wt% and 3wt%) are studied subjected to the evaporative heat load of 20-120W. Swirling, bubble creation and bubble growth phenomena are observed inside OHP integrated with circulation and oscillating motion of vapor plug and liquid slug. Furthermore, deposition of nanoparticles is found on the surface of the evaporative section of OHP when charged with nanofluid. Experimental results show that Cu/Water nanofluid containing 2wt% of Cu nanoparticles facilitates lowest thermal resistance and highest magnitude of pressure fluctuation inside OHP. Maximum 22% efficiency is achieved by Cu/Water nanofluid with 2wt% of Cu nanoparticles at 80Wof evaporative power input. However, thermal performance is found significantly interrelated with inside pressure fluctuation of OHP. Cu/water nanofluid is found to promote circulation and oscillation of the liquid slug and the vapor plug rather than reinforcing bubble formation and bubble growth inside OHP. © 2014 Elsevier Ltd.Md J. Nine, Md. Riyad Tanshen, B. Munkhbayar, Hanshik Chung, Hyomin Jeon

Surfactant-free dispersion of silver nanoparticles into MWCNT-aqueous nanofluids prepared by one-step technique and their thermal characteristics

This paper reports a significant enhancement in the thermal conductivity of silver-nanoparticle-based aqueous nanofluids with the addition of negligible amounts of multi-walled carbon nanotubes (MWCNTs). The present work was conducted using purified MWCNTs/water nanofluids prepared by a wet grinding method. Silver nanoparticles were dispersed into the MWCNT/water nanofluids via a one-step method using pulse power evaporation, which was observed to improve the dispersibility and thermal conductivity of the nanofluids. A particle sizing system (PSS) and transmission electron microscopy (TEM) were used to confirm the size of silver nanoparticles in base fluids. The PSS measurement results reveal that the size of the silver nanoparticles was approximately 100 nm, which is in good agreement with the results obtained from TEM and SEM. The maximum absorbance (2.506 abs at a wavelength of 264 nm) and highest thermal conductivity enhancement (14.5% at 40 °C) were achieved by a fluid containing '0.05 wt% MWCNTs-3 wt% Ag' composite

A numerical investigation on LNG flow and heat transfer characteristic in heat exchanger

Abstract not availableHandry Afrianto, Md. Riyad Tanshen, B. Munkhbayar, U. Tony Suryo, Hanshik Chung, Hyomin Jeon

Experimental investigation of the mechanical grinding effect on graphene structure

Graphene has been proven to be a promising material for various applications due to its outstanding chemical, physical, optical as well as mechanical properties. To further improve these properties of graphene, here we apply a grinding method with various speeds (100–600 rpm) of a planetary ball mill under wet conditions in graphene based aqueous solution. Therefore, the improvements in dispersion and thermal characteristics of the graphene–water solution were investigated based on the morphological and structural changes. The best dispersibility and highest thermal conductivity of graphene–water solution were observed for a grinding speed of 500 rpm. As a result, the grinding speed of 500 rpm is found as the optimum condition of planetary ball milling in the case study. The reason for the grinding speed of 500 rpm revealing the best condition is attributed to the reduced ratio (/D//G=0.221)of the D band and the G band in Raman spectroscopy. We believe that structurally upgraded graphene in this study would greatly improve the performance of the graphene based devices.Munkhshur Myekhlai, B. Munkhbayar, Taejin Lee, Md. Riyad Tanshen, Hanshik Chung and Hyomin Jeon

Thermal conductivity of TiO(2) nanoparticles based aqueous nanofluids with an addition of a modified silver particle

Nanofluid is a colloidal suspension which has received great attention over the past two decades, but its limited heat transfer enhancement is a matter of concern for industrial applications. We demonstrate an improvement in the thermal conductivity of TiO2 nanofluids with an addition of negligible amounts of modified silver “Ag” nanoparticles. In this work, the surface/shape of newly synthesized “Ag” nanoparticles is modified by planetary ball milling. Then, to enhance the thermal conductivity of TiO2 nanofluids, the flattened “Ag” particles are incorporated with the combination of small (15 nm) and large (300 nm) TiO2 nanoparticles in an aqueous solution. The thermal conductivities of Ag/TiO2−water nanofluids with various weight concentrations are measured at temperatures ranging from 15 to 40 °C. As a result, the present study confirms that the thermal conductivity of TiO2 based solution can be improved by introducing the flattened “Ag” particles.Munkhbayar Batmunkh, Md. R. Tanshen, Md. J. Nine, Munkhshur Myekhlai, Heekyu Choi, Hanshik Chung, and Hyomin Jeon

Thermal conductivity of TiO2 nanoparticles based aqueous nanofluids with an addition of a modified silver particle

Nanofluid is a colloidal suspension which has received great attention over the past two decades, but its limited heat transfer enhancement is a matter of concern for industrial applications. We demonstrate an improvement in the thermal conductivity of TiO2 nanofluids with an addition of negligible amounts of modified silver "Ag" nanoparticles. In this work, the surface/shape of newly synthesized "Ag" nanoparticles is modified by planetary ball milling. Then, to enhance the thermal conductivity of TiO2 nanofluids, the flattened "Ag" particles are incorporated with the combination of small (15 nm) and large (300 nm) TiO2 nanoparticles in an aqueous solution. The thermal conductivities of Ag/TiO2 water nanofluids with various weight concentrations are measured at temperatures ranging from 15 to 40 degrees C. As a result, the present study confirms that the thermal conductivity of TiO2 based solution can be improved by introducing the flattened "Ag" particles

Single Axis Solar Tracker for Maximizing Power Production and Sunlight Overlapping Removal on the Sensors of Tracker

This paper presents the design and execution of a solar tracker system devoted to photovoltaic (PV) conversion panels. The proposed single-axis solar tracker is shifted automatically based on the sunlight detector or tracking sensor. This system also removes incident sunlight overlapping from sensors that are inside the sunlight tracking system. The Light Dependent Resistor (LDR) is used as a sensor to sense the intensity of light accurately. The sensors are placed at a certain distance from each other in the tracker system to avoid sunlight overlapping for maximum power production. The total system is designed by using a microcontroller (PIC16F877A) as a brain to control the whole system. The solar panel converts sunlight into electricity. The PV panel is fixed with a vertical axis of the tracker. This microcontroller will compare the data and rotate a solar panel via a stepper motor in the right direction to collect maximum photon energy from sunlight. From the experimental results, it can be determined that the automatic (PV solar tracker) sun tracking system is 72.45% more efficient than fixed panels, where the output power of the fixed panel and automatically adjusted panel are 8.289 watts and 14.287 watts, respectively