Experimental investigation of solar heating of bridge decks

The addition of monomers or the inclusion of wax within highway bridge decks are two methods being used to prevent salt penetration during winter deicing. Both of these methods require the addition of heat until the upper two inches of bridge deck reaches from 160-190 F. This study investigated the potential for using solar energy as a means of providing the required heat. The bridge was modeled analytically and the time varying temperature distribution was determined for both a flat plate type cover collector and focusing collector scheme did show promise for providing the required heat. Both models suffered from lack of accurate thermal properties data for the concrete. Experimental studies were conducted on a simulated bridge deck using flat plate covers and Northrup focusing Fresnel Lens collectors. Neither scheme was able to provide the desired temperatures. A major difficulty encountered was the design of an appropriate heat exchanger to transfer the collected energy from the heat transfer flud to the bridge deck. Several different designs were tested, but none of the methods used would provide the desired bridge deck temperatures for the collector area used. The collectors did not perform up to their expectations.4-77 to 6-79N

Тонкі плівки CdZnO з покриттям: Застосування для пристроїв перетворення енергії

Wide band gap semiconductors have appeared as promising materials suitable for high temperature high frequency high power operations in electronics as well as optoelectronic devices because of their ex-ceptional material characteristics. More specially CdO and ZnO films possess an outstanding ability to ma-terialize short wavelength light emitting devices due to their large band gap energy. CdO and ZnO films are widely used for optoelectronic applications in the short wave length visible-light region especially for laser diodes (LDs) and light emitting diodes (LEDs). In this paper we report structural, optical and electri-cal properties of wide band gap CdZnO thin film prepared by spray-pyrolysis on glass substrate. Charac-terization of the samples was carried out with UV-spectroscopy, Х-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectroscopy and four-probe measurements. The XRD pattern exhibited a mix-ture of cadmium oxide cubic and hexagonal ZnO phases. Surface morphology of sample was identified from SEM micrograph as porous surface. Raman spectra exhibit the strong E2 (High) phonon peak in addition to other multiphonon peaks. Optical absorption spectroscopy and DC conductivity measurements give the optical band gap of 2.87 eV and semiconductor nature with activation energy of 0.33 eV.Широкозонні напівпровідники є перспективними матеріалами, придатними для високотемпера-турних, високочастотних, високоенергетичних операцій в електроніці, а також оптоелектронних при-строях через їх виняткові характеристики. Більш конкретно, на основі плівок CdO і ZnO можна реалі-зувати короткохвильові пристрої, що випромінюють світло, завдяки великій ширині забороненої зони. Плівки CdO і ZnO широко використовуються для оптоелектронних приладів в області короткохвильо-вого видимого світла, особливо для лазерних діодів і світлодіодів. У даній роботі наведено структурні, оптичні та електричні властивості широкозонної тонкої плівки CdZnO, одержаної методом спрей-піролізу на скляній підкладці. Визначення характеристик зразків проводили за допомогою УФ-спектроскопії, рентгенівської дифракції, скануючого електронного мікроскопа, комбінаційної спектро-скопії та чотиризондових вимірювань. На рентгенограмі виявлено суміш кубічної та гексагональної фаз оксиду кадмію. Морфологію поверхні зразка ідентифікували за допомогою скануючого електрон-ного мікроскопа як пористу поверхню. Спектри комбінаційного розсіювання світла показують силь-ний фононний пік на додаток до інших багатофононних піків. Оптично-абсорбційна спектроскопія та вимірювання провідності постійного струму дають оптичну ширину забороненої зони 2.87 еВ і напівп-ровідникову природу з енергією активації 0.33 еВ

Comparison of p.o. or i.v. proton pump inhibitors on 72-h intragastric pH in bleeding peptic ulcer

BACKGROUND AND AIMS: After successful endoscopic hemostasis in bleeding peptic ulcer, addition of proton pump inhibitors reduce the rate of recurrent bleeding by maintaining intragastric pH at neutral level. The aim of the present study was to evaluate the effect of various proton pump inhibitors given through different routes on intragastric pH over 72 h after endoscopic hemostasis in bleeding peptic ulcer

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions. © Copyright