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Thermophysical Properties

Arsalan Mirjafari, Taha Hmissa, Xiafei Zhang, Nilesh Dhumal, Gregory McManus, Xu Zhou, Hunaid Nulwala
Ionic liquids with bifluoride anions possess properties such as high conductivity, wide electrochemical windows and low viscosity, which make them attractive materials for various electrochemical devices. However, due to the lack of reliable synthetic routes, bifluoride-based ionic liquids have seldom been explored. Herein, an autocatalytic strategy for the HF-free synthesis of bifluoride-based sulfonamide ionic liquids via the sulfur(VI) fluoride exchange (SuFEx) reaction was reported. This reaction requires no chromatographic purification and yields are quantitative...
August 15, 2018: Angewandte Chemie
Francisco Cordovilla, Ángel García-Beltrán, Miguel Garzón, Diego A Muñoz, José L Ocaña
One of the main limiting factors for a widespread industrial use of the Selective Laser Melting Process it its lack of productivity, which restricts the use of this technology just for high added-value components. Typically, the thickness of the metallic powder that is used lies on the scale of micrometers. The use of a layer up to one millimeter would be necessarily associated to a dramatic increase of productivity. Nevertheless, when the layer thickness increases, the complexity of consolidation phenomena makes the process difficult to be governed...
August 12, 2018: Materials
Renata S Rabelo, Isabela F Oliveira, Vanessa M da Silva, Ana S Prata, Miriam D Hubinger
A nanostructured lipid carrier (NLC) has been developed as a loading system for Vitamin D (VD). The NLCs were obtained by melt-emulsification method and coated with chitosan (CHI) by electrostatic deposition. The lipids used in the formulations were selected in order to provide higher encapsulation efficiency. Thermophysical properties of particles were evaluated by differential scanning calorimetry; particle stability was characterized by size distribution, polydispersity index, zeta-potential and light backscattering...
July 28, 2018: International Journal of Biological Macromolecules
Yajnaseni Biswas, Pratyush Ghosh, Tarun K Mandal
In this article, we demonstrate design and synthesis of a series of zwitterionic ionic liquids (ZILs) to understand the structure-property relationship towards the increase of thermal stability, variation of glass transition temperature, shape-tuning of nanostructured aggregates and tuning of stimuli-responsiveness. The substitution reaction of imidazole with various aliphatic and aromatic bromides followed by the reaction of the corresponding substituted imidazoles with bromoalkyl carboxylic acids of varying spacer length produces these ZILs...
July 3, 2018: Chemistry: a European Journal
Yoshihiro Takasugi, Koichi Futagawa, Takashi Umeda, Kouhei Kazuhara, Satoshi Morishita
Thermosoftening treatment of polyvinyl chloride (PVC) nasotracheal tubes (NTTs) can reduce the incidence and amount of epistaxis during nasotracheal intubation. The optimal thermal setting for thermosoftening treatment of NTTs without burn injury was investigated. Two composite types of PVC NTTs were used. Following withdrawal of the PVC NTTs from a bottle of water at 45 or 60°C, the changes in the surface temperature of the NTTs were measured by infrared thermography. Hardness of the NTTs at 25, 30, 35, and 40°C was measured...
2018: Anesthesia Progress
Tuan A H Nguyen, Simon R Biggs, Anh V Nguyen
Current analytical models for sessile droplet evaporation do not consider the nonuniform temperature field within the droplet and can overpredict the evaporation by 20%. This deviation can be attributed to a significant temperature drop due to the release of the latent heat of evaporation along the air-liquid interface. We report, for the first time, an analytical solution of the sessile droplet evaporation coupled with this interfacial cooling effect. The two-way coupling model of the quasi-steady thermal diffusion within the droplet and the quasi-steady diffusion-controlled droplet evaporation is conveniently solved in the toroidal coordinate system by applying the method of separation of variables...
June 12, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Richard A Messerly, S Mostafa Razavi, Michael R Shirts
In this study, we present an approach for rapid force field parameterization and uncertainty quantification of the non-bonded interaction parameters for classical force fields. The accuracy of most thermophysical properties, and especially vapor-liquid equilibria (VLE), obtained from molecular simulation depends strongly on the non-bonded interactions. Traditionally, non-bonded interactions are parameterized to agree with macroscopic properties by performing large amounts of direct molecular simulation. Due to the computational cost of molecular simulation, surrogate models (i...
June 12, 2018: Journal of Chemical Theory and Computation
Shila Shirdel Ghadikolaei, Abdollah Omrani, Morteza Ehsani
The BCNs were chemically modified using acetic anhydride with the aim of improving its dispersion and interfacial adhesion. Acetylation of BCNs was confirmed by FT-IR spectroscopy. Morphology studies using TEM and SEM revealed that a reasonable dispersion of the modified BCNs in the EVA matrix was accomplished. The DSC data displayed a little shift in the Tg to higher temperatures with the incorporation of both modified and unmodified BCNs. Increased thermal stability of the nanocomposites consisting acetylated BCNs was confirmed by TGA technique...
August 2018: International Journal of Biological Macromolecules
Brian Wowk, Gregory M Fahy, Susan Ahmedyar, Michael J Taylor, Yoed Rabin
Vitrification tendency and stability of the amorphous state were analyzed by means of differential scanning calorimetry (DSC) for the vitrification solution DP6, with and without additional solutes to enhance ice suppression. This study is a part of an ongoing research effort to characterize the thermophysical and mechanical properties of DP6 and its derivatives, and their qualities as cryoprotective solutions. DP6 was determined to have a critical cooling rate necessary to ensure vitrification of 2.7 °C/min...
June 2018: Cryobiology
Xiaoyi Zhu, David M Phinney, Sravanti Paluri, Dennis R Heldman
Specific heat capacity (cp ) is a temperature dependent physical property of foods. Lipid-being a macromolecular component of food-provides some fraction of the food's overall heat capacity. Fats/oils are complex chemicals that are generally defined by carbon length and degree of unsaturation. The objective of this investigation was to use advanced specific heat capacity measurement to determine the effect of fatty acid chemical structure on specific heat capacity of food lipids. In this investigation, the specific heat capacity of a series of triacylglycerols were measured to quantify the influence of fatty acid composition on specific heat capacity based on two parameters; the -average carbon number (C) and the average number of double bonds (U)...
April 2018: Journal of Food Science
Zachary H Levine
A measurement of a thermophysical property of water is made using items found in the author's home. Specifically, the ratio of the energy required to heat water from the melting point to boiling to the energy required to completely boil away the water is found to be 5.7. This may be compared to the standard value of 5.5. The close agreement is not representative of the actual uncertainties in this simple experiment. Heating water in a microwave oven can let a student apply the techniques of quantitative science based on questions generated by his or her scientific curiosity...
February 2018: The physics teacher
Annalisa Dalmoro, Carlo Naddeo, Silvestro Caputo, Gaetano Lamberti, Liberata Guadagno, Matteo d'Amore, Anna Angela Barba
This study is focused on the characterization of the thermal behavior and physical properties of the most consumed legumes in the daily diet such as beans, lentils and chickpeas. Because of a lack of information in the literature about the effect of microwave treatments on legumes, characterization protocols have been applied before and after subjecting them to microwave irradiation suitable for pest disinfestation. The effects of two different radiative treatments, one suitable for inactivating the infesting fauna and the other simulating uncontrolled treatments, characterized by very high temperatures, were tested...
March 1, 2018: Food & Function
Shanguo Zhao, Guoying Xu, Ning Wang, Xiaosong Zhang
The solar gravity heat pipe has been widely used for solar thermal water heating because of its high efficient heat transfer and thermal diode characteristics. Operated on fluctuant and low intensity solar radiation conditions, a solar gravity heat pipe may frequently start up. This severely affects its solar collection performance. To enhance the thermal performance of the solar gravity heat pipe, this study proposes using graphene/water nanofluid as the working fluid instead of deionized water. The stability of the prepared graphene/water nanofluid added with PVP was firstly investigated to obtain the optimum mass ratios of the added dispersant...
January 28, 2018: Nanomaterials
Valery Ya Rudyak, Andrey V Minakov
This paper discusses the current state of knowledge of the thermophysical properties of nanofluids. The viscosity, thermal conductivity and heat transfer of nanofluids are considered. Experimental and molecular dynamics data are presented. It is shown that viscosity and thermal conductivity of nanofluids generally cannot be described by classical theories. The transport coefficients of nanofluids depend not only on the volume concentration of the particles but also on their size and material. The viscosity increases with decreasing the particle size while the thermal conductivity increases with increasing the particle size...
January 31, 2018: European Physical Journal. E, Soft Matter
Bo Song, Jonathan M Waldrop, Xiaopo Wang, Konrad Patkowski
We have developed a new krypton-krypton interaction-induced isotropic dipole polarizability curve based on high-level ab initio methods. The determination was carried out using the coupled-cluster singles and doubles plus perturbative triples method with very large basis sets up to augmented correlation-consistent sextuple zeta as well as the corrections for core-core and core-valence correlation and relativistic effects. The analytical function of polarizability and our recently constructed reference interatomic potential [J...
January 14, 2018: Journal of Chemical Physics
Chenyang Wen, Xianyang Meng, Marcia L Huber, Jiangtao Wu
The Paris Agreement on climate change, in which many nations have agreed to limit greenhouse gas emissions, has spurred interest in developing working fluids with low global warming potential (GWP) that can satisfy environmental concerns and have thermophysical properties that can meet engineering performance requirements. One such fluid is 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone (also known as Novec-649 and Novec-1230), which has potential applications in organic Rankine cycles (ORC), electronics cooling, computer/data center cooling and fire extinguishing...
October 12, 2017: Journal of Chemical and Engineering Data
Abdelmajid Bousselham, Omar Bouattane, Mohamed Youssfi, Abdelhadi Raihani
The aim of this paper is to present a GPU parallel algorithm for brain tumor detection to estimate its size and location from surface temperature distribution obtained by thermography. The normal brain tissue is modeled as a rectangular cube including spherical tumor. The temperature distribution is calculated using forward three dimensional Pennes bioheat transfer equation, it's solved using massively parallel Finite Difference Method (FDM) and implemented on Graphics Processing Unit (GPU). Genetic Algorithm (GA) was used to solve the inverse problem and estimate the tumor size and location by minimizing an objective function involving measured temperature on the surface to those obtained by numerical simulation...
January 2018: Journal of Thermal Biology
Marco A Marcos, David Cabaleiro, María J G Guimarey, María J P Comuñas, Laura Fedele, Josefa Fernández, Luis Lugo
This study presents new Nano-enhanced Phase Change Materials, NePCMs, formulated as dispersions of functionalized graphene nanoplatelets in a poly(ethylene glycol) with a mass-average molecular mass of 400 g·mol-1 for possible use in Thermal Energy Storage. Morphology, functionalization, purity, molecular mass and thermal stability of the graphene nanomaterial and/or the poly(ethylene glycol) were characterized. Design parameters of NePCMs were defined on the basis of a temporal stability study of nanoplatelet dispersions using dynamic light scattering...
December 29, 2017: Nanomaterials
Mohammad Amani, Pouria Amani, Alibakhsh Kasaeian, Omid Mahian, Ioan Pop, Somchai Wongwises
This research investigates the applicability of an ANN and genetic algorithms for modeling and multiobjective optimization of the thermal conductivity and viscosity of water-based spinel-type MnFe2 O4 nanofluid. Levenberg-Marquardt, quasi-Newton, and resilient backpropagation methods are employed to train the ANN. The support vector machine (SVM) method is also presented for comparative purposes. Experimental results demonstrate the efficacy of the developed ANN with the LM-BR training algorithm and the 3-10-10-2 structure for the prediction of the thermophysical properties of nanofluids in terms of the significantly superior accuracy compared to developing the correlation and employing SVM regression...
December 12, 2017: Scientific Reports
Hedieh Torabifard, Luke Reed, Matthew T Berry, Jason E Hein, Erik Menke, G Andrés Cisneros
The development of Li-ion batteries for energy storage has received significant attention. The synthesis and characterization of electrolytes in these batteries are an important component of this development. Ionic liquids (ILs) have been proposed as possible electrolytes in these devices. Thus, the accurate determination of thermophysical properties for these solvents becomes important for determining their applicability as electrolytes. In this contribution, we present the synthesis and experimental/computational characterization of thermodynamic and transport properties of a pyrrolidinium based ionic liquid as a first step to investigate the possible applicability of this class of ILs for Li-ion batteries...
October 28, 2017: Journal of Chemical Physics
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