41 research outputs found
Convective heat transfer from circular cylinders located within perforated cylindrical shrouds
The influence of perforated cylindrical shrouds on the convective heat transfer to circular cylinders in transverse flow has been studied experimentally. Geometries studied were similar to those used in industrial platinum resistance thermometers. The influence of Reynolds number, ventilation factor (ratio of the open area to the total surface area of shroud), radius ratio (ratio of shroud's inside radius to bare cylinder's radius), and shroud orientation with respect to flow were studied. The experiments showed that perforated shrouds with ventilation factors in the range 0.1 to 0.4 and radius ratios in the range 1.1 to 2.1 could enhance the convective heat transfer to bare cylinders up to 50%. The maximum enhancement occurred for a radius ratio of 1.4 and ventilation factors between 0.2 and 0.3. It was found that shroud orientation influenced the heat transfer, with maximum heat transfer generally occurring when the shroud's holes were centered on either side of the stagnation line. However, the hole orientation effect is of second order compared to the influence of ventilation factor and radius ratio
Directional emittance surface measurement system and process
Apparatus and process for measuring the variation of directional emittance of surfaces at various temperatures using a radiometric infrared imaging system. A surface test sample is coated onto a copper target plate provided with selective heating within the desired incremental temperature range to be tested and positioned onto a precision rotator to present selected inclination angles of the sample relative to the fixed positioned and optically aligned infrared imager. A thermal insulator holder maintains the target plate on the precision rotator. A screen display of the temperature obtained by the infrared imager, and inclination readings are provided with computer calculations of directional emittance being performed automatically according to equations provided to convert selected incremental target temperatures and inclination angles to relative target directional emittance values. The directional emittance of flat black lacquer and an epoxy resin measurements obtained are in agreement with the predictions of the electromagnetic theory and with directional emittance data inferred from directional reflectance measurements made on a spectrophotometer
COMPARISON OF SECOND-DEGREE BURNS HEALING TIME IN TWO METHODS OF DRESSING WITH FUNDERMOL HERBAL OINTMENT AND% 1 SILVER SULFADIAZINE OINTMENT
BACKGROUND: Burn wounds are one of the health problems in modern societies that are associated with irreparable harms
and many side problems for patients and their families. Infection due to burn wounds is the main cause of death in such
patients. One of the methods to prevent infection of burn wounds is topical antibiotic ointments. This study aimed to investigate
and identify effective ointments to treat burn wounds. For this purpose, the effects of two types of ointment, fundermol
and 1% silver sulfadiazine cream on second degree burn wounds were compared.
METHODS: This was a clinical trial study conducted in 2008. Using convenient and continuous sampling method, 50 patients
referred to Imam Mousa Kazem Burn Injury Clinic in Isfahan, Iran with 2nd degree burn wounds in 1% to 10% surface
area were enrolled. The patients were randomly divided into two groups of treatment with fundermol and sulfadiazine
and the dressing was changed once a day. The healing time for burn wounds in each patient was recorded in a checklist
and data were analyzed by independent t-test via SPSS software.
RESULTS: The healing time of burn wounds in the group treated with fundermol was shorter than that in the group treated
with sulfadiazine (p < 0.001).
CONCLUSIONS: The present study showed that fundermol ointment accelerates burn wound healing. Therefore, fundermol
can be introduced as a good replacement for current treatments of burn wounds
Surface temperature measurements using a thin film thermal array
A thin film device was designed and fabricated to measure surface temperatures. An array of eight integrated thermal sensors are mounted on a 0.002 inch (0.05 mm) Kapton film and multiplexed to obtain an area thermal measurement. The device was tested on a flat plate airfoil and demonstrated a temperature variation of 0.55 C maximum and 0.05 C minimum compared to embedded thermocouples. Future improvements are also discussed
Emissivity Results on High Temperature Coatings for Refractory Composite Materials
The directional emissivity of various refractory composite materials considered for application for reentry and hypersonic vehicles was investigated. The directional emissivity was measured at elevated temperatures of up to 3400 F using a directional spectral radiometric technique during arc-jet test runs. A laboratory-based relative total radiance method was also used to measure total normal emissivity of some of the refractory composite materials. The data from the two techniques are compared. The paper will also compare the historical database of Reinforced Carbon-Carbon emissivity measurements with emissivity values generated recently on the material using the two techniques described in the paper
Thermal conductivity of refractory glass fibres
In the present study, the current international
standards and corresponding apparatus for measuring the
thermal conductivity of refractory glass fibre products have
been reviewed. Refractory glass fibres are normally produced
in the form of low-density needled mats. A major
issue with thermal conductivity measurements of these
materials is lack of reproducibility in the test results due to
transformation of the test material during the test. Also
needled mats are inherently inhomogeneous, and this poses
additional problems. To be able to compare the various
methods of thermal conductivity measurement, a refractory
reference material was designed which is capable of
withstanding maximum test temperatures (1673 K) with
minimum transformation. The thermal conductivity of this
reference material was then measured using various
methods according to the different standards surveyed. In
order to compare different materials, samples have been
acquired from major refractory glass fibre manufacturers
and the results have been compared against the newly
introduced reference material. Materials manufactured by
melt spinning, melt blowing and sol–gel have been studied,
and results compared with literature values