نتایج جستجو برای: thermal cycles

تعداد نتایج: 304319  

2017
Tingting Qian Jinhong Li Wuwei Feng Hong’en Nian

A striking contrast in the thermal conductivities of polyethylene glycol (PEG)/diatomite form-stable phase change composite (fs-PCC) with single-walled carbon nanotubes (SWCNs) as nano-additive has been reported in our present study. Compared to the pure PEG, the thermal conductivity of the prepared fs-PCC has increased from 0.24 W/mK to 0.87 W/Mk with a small SWCNs loading of 2 wt%. SWCNs are ...

2017
Nadja Rohr Jens Fischer

BACKGROUND Resin composite cements are used in dentistry to bond ceramic restorations to the tooth structure. In the oral cavity these cements are subjected to aging induced by masticatory and thermal stresses. Thermal cycling between 5 and 55 °C simulates the effect of varying temperatures in vitro. Purpose of this study was to compare indirect tensile to compressive strength of different ceme...

Journal: :Entropy 2017
Per Lundqvist Henrik Öhman

Analysis of global energy efficiency of thermal systems is of practical importance for a number of reasons. Cycles and processes used in thermal systems exist in very different configurations, making comparison difficult if specific models are required to analyze specific thermal systems. Thermal systems with small temperature differences between a hot side and a cold side also suffer from diff...

Aida Moradi, Masumeh Hasani Tabatabaei, Sara Valizadeh, Sedighe Hashemi Kamangar,

Background and Aim: Improving the bond strength at the resin-dentin interface is an important challenge in adhesive dentistry. This study examined the effect of low-power, non-thermal atmospheric pressure plasma (NT-APP) treatments on the adhesion of a self-adhesive resin composite to dentin. Materials and Methods: In this experimental in-vitro study, buccal enamel of extracted bovine incisors...

2007
A. R. King

We give a global analysis of mass transfer variations in CVs. We show that limit cycles driven by variations of the secondary star's radius alone require this radius to be sensitive to the instantaneous mass transfer rate. The only promising mechanism for this is irradiation of the secondary by the accreting primary. Explicit modelling of this process shows however that cycles do not occur for ...

Journal: :The Journal of the Acoustical Society of America 1999
M D Seale E I Madaras

Lamb waves offer a promising method of evaluating damage in composite materials. The Lamb wave velocity is directly related to the material parameters, so an effective tool exists to monitor damage in composites by measuring the velocity of these waves. The Lamb Wave Imager (LWI) uses a pulse/receive technique that excites an antisymmetric Lamb mode and measures the time-of-flight over a wide f...

Die casting process is used since long, but even today problems like erosion, corrosion, soldering and sticking affect die life. These dies undergo thermal cyclic loads from 70 oC to 600 oC during processing. Physical Vapor Deposition (PVD) hard coating can play an important role in such extreme applications. In the present work, we report the use of Chromium based multila...

Journal: :Europan journal of science and technology 2021

In this study, energetic performance analysis of an endoreversible modified dual cycle is performed. context, the net work and thermal efficiency cycle, are formulated with respect to certain basic design parameters. Also, conditions for maximum investigated, classical cycles, compression ratio that maximizes analytically obtained extreme temperature ratio, isothermal expansion cutoff ratio. Th...

2001
J. GUCKENHEIMER

Slow-fast systems on the two-torus T 2 provide new effects not observed for systems on the plane. Namely, there exist families without auxiliary parameters that have attracting canard cycles for arbitrary small values of the time scaling parameter ε. In order to demonstrate the new effect, we have chosen a particularly simple family, namely ẋ = a − cosx − cos y, ẏ = ε, a ∈ (1, 2) being fixed. T...

Journal: :Journal of occupational and environmental hygiene 2011
Catherine O'Brien Laurie A Blanchard Bruce S Cadarette Thomas L Endrusick Xiaojiang Xu Larry G Berglund Michael N Sawka Reed W Hoyt

Personal protective equipment (PPE) refers to clothing and equipment designed to protect individuals from chemical, biological, radiological, nuclear, and explosive hazards. The materials used to provide this protection may exacerbate thermal strain by limiting heat and water vapor transfer. Any new PPE must therefore be evaluated to ensure that it poses no greater thermal strain than the curre...

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