In this research, Mechanical response and energy absorption of ceramic foam sandwich panels filled with Newtonian and non-Newtonian fluid subjected to quasi-static indentation loads were investigated experimentally. In addition, the effects of number of face-sheet layers (face-sheet thickness) and boundary conditions on the mechanical response and energy absorption of sandwich panels were discussed. Sandwich panels consisted of two glass/epoxy face-sheets with different thicknesses (4 and 8 layers) and an open cell ceramic foam core. This foam saturated with Newtonian (Glycerol) and non-Newtonian (mixture of Ethylene glycol and Aerosil) fluids. Sandwich panels were tested in two different kinds of supporting conditions, simply-supported and

This work presents a model of kinetic theory of fracture for predicting the fatigue life of carbon fiber/epoxy composite ring from a combination of thermogravimetric analyses and Fourier transform infrared spectroscopy of mechanical tests under different loading strains and investigates the effect of environmental exposure on the surface morphology, thermal, and fatigue properties of the composite ring. Three kinetic parameters of the model are first calibrated by means of experimental data. Then, the model is capable of predicting the fatigue life of the composite ring under ambient condition. Eventually, the influence of material constant on the fatigue life of the composite ring is studied. The main result of this work is the arrangemen

Graphene reinforced polymer derived carbon (carbon/graphene) aerogels were synthesized by carbonization of novolac/graphene oxide aerogels. Novolac/graphene oxide aerogels were synthesized using solvent-saturated-vapor-atmosphere technique. To this aim, 20 wt% solution of novolac resin with 0, 2, and 5 wt% graphene oxide in 2-propanol were made and were cured in an autoclave. Wet aerogels were dried in air and were carbonized at 800 ?C in nitrogen atmosphere. Eliminating the time-consuming methods of drying like supercritical and freeze drying is one of the advantages of this method of synthesis of organic aerogles. Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, nitrogen adsorp

Polyethylene glycol (PEG) is established as an organic solid–liquid phase-change material (PCM) offering a wide range of enthalpies and phase transition temperatures as a function of its molecular weight. PCMs are known for their high-energy absorbance; however, they also have two main drawbacks of leakage and enthalpy reduction during melting. In this work, polyethylene glycol as a phase-change material and graphene oxide (GO), expanded graphene (EG), and epoxy resin (EP) as shape stabilizing materials were used and designed based on experimental design—Taguchi method to find the composition with the least molten PEG leakage and the highest enthalpy of melting. Based on improvements made on main drawbacks, two samples were introduced,

This article aims to analyze heat transfer behavior based on morphological investigation of polymeric novolac aerogel insulation material. In other words, a nano-scale cubic-like structural model was proposed in consideration of novolac aerogel homogeneity only by using FESEM image in order to review scale effect on heat transfer and also structure related variables. The results show that aerogel colloids scale variation from micro to nano has remarkable influence on microstructure properties such as porosity, density, wall thickness, effective thermal conductivity the same as heat transfer performance. Results validation with experimental data turned out to be in acceptable resemblance that introduces structural model as decent and accurat

In this study, a high-performance multilayer super insulation with improved thermal characteristics was manufactured by novolac aerogel/polyester mat as a spacer layer. The novolac aerogel blankets were prepared through the sol–gel polymerization method under vapor of solvent-saturated atmosphere in the presence of the polyester mat. The effect of novolac resin concentration in the initial sol and the layer density on the thermal performance of the novolac aerogels and the multilayer insulations (MLIs) with and without aerogel blankets were studied in details from morphological and thermo-physical points of view. The results indicated that the MLI with 12 aerogel blanket spacer layers, each spacer layer of which had a density of 0.173?g/c

This work deals with the synthesis and physico-chemical characterization of nanoencapsulated paraffin wax with polyurethane (PU) via interfacial polymerization method. In synthesized nanocapsules, the paraffin wax has a function of phase change material, while PU acts as a shell material. The nanoencapsulated PCMs were characterized chemically and morphologically by using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results of morphological study showed that the particle size distribution of the nanocapsules were 80–400 nm by digimizer analysis.

Today, hydrogel plugs as a new and effective technology are widely used for temporary oil and gas well plugging. Although, the strength and fluidity of the hydrogels in the oil wells conditions are still most important challenges in their applications in workover operation. In this study, silica nanoparticles were used to improve the network characteristics and strength of hydrogels in addition to reduce the viscosity. It was found that network parameter can be introduced as an effective method for finding the optimum concentration of silica nanoparticles; by application of this method, rheology study is not necessary. The bottle and rheological tests were used to determine the hydrogel strength in desired oil well conditions (high temperat

The recently global energetic context is recognized by a requirement to reduce our energy consumption, to prolong the fossil fuel shortage, and to decelerate greenhouse gas transpiration. In order to reduce energy consumption, using insulator and decrease its thermal conductivity recognized as the most effective way over the last few years. Aerogels as super insulating materials permit reducing the heat exchange between two environments while producing via the facile sol-gel and divers drying routes. Aerogels have intrigued scientists and engineers due to their unique nano characteristics, such as low density, fine internal void spaces and open-pore geometry, which originate from sol particles 3D random network. Noteworthy, aerogel-based ma