نتایج جستجو برای: polyurethane
تعداد نتایج: 6803 فیلتر نتایج به سال:
BACKGROUND Improvements in the design of the endotracheal tube (ETT) have been achieved in recent years. We evaluated tracheal injury associated with ETTs with novel high-volume low-pressure (HVLP) cuffs and subglottic secretions aspiration (SSA) and the effects on mucociliary clearance (MCC). METHODS Twenty-nine pigs were intubated with ETTs comprising cylindrical or tapered cuffs and made o...
Polyurethanes (PURs) are very versatile polymeric materials with a wide range of physical and chemical properties. PURs have desirable properties such as high abrasion resistance, tear strength, shock absorption, flexibility and elasticity. Although they have relatively poor thermal stability, this can be improved by using treated clay. Polyurethane/clay nanocomposites have been synthesized fro...
There are only a few published reports describing the pathology of regional lymph nodes from patients with silicone breast implants. Systematic analytical chemical verification of foreign material has not previously been reported. In this study, biopsies of regional lymph nodes from 96 patients with breast implants were studied using conventional histology as well as laser-Raman microprobe spec...
N. Burham; S.M.Abdel-Azeem; M. F. El-Shahat, Separation and determination of trace amounts of zinc, lead, cadmium and mercury in tap and qaroun lake water using polyurethane foam functionalized with 4-hydroxytoluene and 4-hydroxyacetophenone,Analytica Chimica Acta 579 (2006) 193–201. Abstract : N. Burham; S.M.Abdel-Azeem; M. F. El-Shahat, Determination of lead and cadmium in tap water and apple...
objective: in order to improve the water solubility and bioavailability of curcumin in cancer therapy, we prepared and tested a novel waterborne cationic polyurethane (pu) as a nano-carrier for curcumin loading (cu-pu). we studied the effect of this prepared nano-drug on melanoma (f10b16) and fibroblasts cells (l929). methods: morphology, size and cell internalization ability of the prepared n...
Corrosion is one of the major problems in the oil and gas industry is one that automatically allocates huge sums annually. Polyurethane is a thermoses polymer with various applications. Using form this polymer has spread for military applications by Otto Bayer in 1930. In one general look polyurethane is product of Iso Syanate and ploy with each other, So that: Iso + ploy = polyurethane. Spend ...
Silicone is a polymer widely used for medical purposes, including breast implants. The aim of this work is to verify the occurrence of silicone gel diffusion through the lining membrane (bleed) of gel breast implants with smooth, textured, and polyurethane foam coated surfaces, sterilized by dry heat and ethylene oxide. The results enable us to conclude that there is significant difference for ...
Comparing to the conventional bath heating, the effects of liquefaction parameters on the degree of liquefaction of wood in polyhydric alcohols by using microwave as an energy source were evaluated. Polyurethane foams were successfully prepared from the liquefied biomass-based polyols. The effects of heating methods (conventional bath heating and microwave) and liquefaction reaction time on the...
In this research scotch pine (Pinus sylvestris L.), Eastern beech (Fagus orientelis L.), oak (Quercus petraea L.) samples have been covered with polyurethane, acrylic, cellulosic varnish. In order to determine the physical changes which occurred on varnish layers caused by steam and wet heat, the samples were exposed to TS 4982 EN 12721 wet heat and TS EN 438-2 steam. According the results, the...
Spray application of polyurethane foam for thermal insulation of buildings represents the polyurethane application with the highest potential worker exposure to MDI. This paper reviews the existing work done to characterize the MDI exposures of the sprayed polyurethane foam workers as well as identifying several elements of an effective industrial hygiene program suggested by the existing work....
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