Optimisers for the Brascamp-Lieb inequality

The Double C Block (DCB) is an innovative composite Concrete Masonry Unit (CMU) developed to offer enhanced thermal performance over standard hollow core blocks (HCBs). The DCB features an original design consisting of a polyurethane (PUR) foam inserted between two concrete c-shaped layers, thus acting as the insulating layer and the binding agent of the two concrete elements simultaneously. The purpose of this research is to describe the results obtained when assessing the thermal transmittance (UDCB and UHCB) of these blocks using three different methodologies: theoretical steady-state U-value calculations, numerical simulation using a Finite Element Method (FEM), and in situ monitoring of the U-value by means of the Heat Flow method (HFM). The results obtained show that the three methodologies corroborated each other within their inherent limitations. The DCB showed a performance gap of 52.1% between the predicted FEM simulation (UDCB was 0.71 W/(m2K)) and the values measured via HFM, which converged at 1.47 W/(m2K). Similarly, a gap of 19.9% was observed when assessing the HCB. The theoretical value via FEM of UHCB was 1.93 W/(m2K) and the measured one converged at 2.41 W/(m2K). Notwithstanding this, the DCB showed superior thermal performance over the traditional block thanks to a lower U-value, and it complies with the Maltese building energy code. Further improvements are envisaged.

Sustainable construction materials for low-cost housing: Thermal insulation potential of expanded SBR composites with leather waste

<p>The Arctic MArine Geoscience Expedition (AMAGE) program led by the Korea Polar Research Institute (KOPRI) is a multidisciplinary undertaking to investigate the geological environment and methane release phenomena in the Arctic seas. The icebreaking research vessel (IBRV) Araon has carried out three expeditions in the Chukchi Plateau (CP) and the East Siberian Seas in 2016, 2018 and 2019. In the first 2016 expedition, a chain of topographic mounds (with the height of several tens meters and the width of hundreds meters) was identified by subbottom profiler and multibeam bathymetric survey in the western continental slope of the CP. Gas hydrate samples were first retrieved in the Araon Mound-6 among the mound structures in the CP and ESS areas during the expedition. The detailed morphology and subsurface structures of the mounds were mapped from the subsequent expeditions in 2018 and 2019. More gas hydrate samples were obtained in the Araon Mound-3 and Araon Mound-6 in these expeditions. To examine gas hydrate occurrence conditions, we conducted geophysical surveys including seismic (sparker in 2018 and multi-channel in 2019) and heat flow methods during these expeditions. The seismic profiles obtained using two seismic methods show very well-developed bottom simulating reflectors (BSRs) which are widespread on the western slope of the study area. The BSR depths detected on the seismic profiles are well coincided with the depths of the lower boundary of the gas hydrate stability zone calculated from the geothermal gradient of heat flow measurement.</p><p>Arctic gas hydrates are considered to be vulnerable to the ongoing rapid Arctic warming. The AMAGE program will provide comprehensive understanding on poorly-known gas hydrate in the Arctic in the various research fields of geology, geophysics, geochemistry, biogeoscience, and oceanography.</p>

Summary This work demonstrates the possibilities of the marine geothermy (heat flow methods) to reconstruct the formation process of heat-related geological objects with an example of 2D inversion of data from in-situ temperature measurements in seafloor sediments for gas hydrate deposit study in Danube paleodelta, Black Sea.

Temperature changes affect pavement performance such as strength reduction at elevated temperature or crack initiation and development at low thermal conditions. Thermal diffusivity of paving materials is one of parameters helps to determine exactly temperature distribution in pavement structures. Currently, the thermal diffusivity can be determined through thermal conductivity, mass density of material, and specific heat capacity. Nevertheless, the specific heat capacity is quite complicated to obtain for composite materials. Literature reported different experimental methods used for determining the thermal conductivity of building materials such as heat flow method (ASTM C 518), guarded-hot-plate approach (ASTM C 177), hot wire technique (ASTM C 1113), and transient plane heat source solution (ISO 22007-2:2015). However, these methods were found not suitable for pavements due to large granular sizes and heterogeneous properties of pavement materials. This study developed a device to determine the thermal diffusivity of pavement materials in the laboratory without the needs of heat capacity and thermal conductivity of the composites. The temperature distributed in the hot mixed asphalt concrete type 19 having air void content of 9.7%, bitumen content of 4%, and density of 2.14 (T/m3) was first measured by this device. The thermal diffusivity was then determined based on the heat transfer theory, and the result was 4.556 × 10−7(m2/s), consistent with the one from previous studies.

Effect of Sb and In additives on thermal and electrical properties of Sn–9Zn–4Bi alternative lead-free solder alloy

The present article investigates the collective influence of chemical reaction, viscous dissipation and Hall current magnetic effects on timedependent radiative magnetohydrodynamic flow, heat and mass transfer from an inclined wall embedded in a homogenous, isotropic highpermeability porous medium. The model developed is relevant to near wall magnetohydrodynamic energy generator transport phenomena in which chemical corrosion effects may arise during operations. The governing non-linear partial differential equations for mass, momentum, energy and species conservation are transformed into a system of coupled non-linear dimensionless partial differential equations with appropriate similarity variables. The normalized conservation equations are then solved with a robust finite element method (MATLABFEM) subject to corresponding initial and boundary conditions. Important dimensionless parameters emerging are Eckert number, thermal Grashof number, solutal Grashof number, magnetic body force parameter, Hall parameter, permeability parameter, Dufour number, Soret number, time, radiation-conduction parameter, chemical reaction parameter, heat absorption parameter, Prandtl number, Schmidt number and wall angle. Primary velocity is enhanced with Eckert number, thermal Grashof number, solutal Grashof number, Hall parameter, permeability parameter, Dufour number, Soret number, radiation-conduction parameter and time whereas it is reduced with first order chemical reaction parameter, heat absorption, magnetic body force parameter, Prandtl number, Schmidt number and wall inclination. Secondary velocity is elevated with Eckert number, solutal Grashof number, thermal Grashof number, magnetic body force parameter, Hall parameter, radiation-conduction parameter, Dufour number, Soret number and time whereas it is suppressed with reaction parameter, heat absorption, Prandtl number, Schmidt number and wall inclination. Temperature is enhanced with Eckert number, Dufour number, heat absorption, radiation-conduction parameter and time whereas it is depressed with Prandtl number. Species concentration is reduced with increasing chemical reaction parameter (destructive homogenous reaction) and Schmidt number whereas it is elevated with Soret number and time. Extensive discussion of the finite element formulation, convergence and validation is provided Skin friction, Nusselt number and Sherwood number distributions are also provided for selected parameter variation. Validation of solutions with published literature is also included for several special cases, namely non-reactive, non-dissipative flow in the absence of heat generation or absorption. Further validation is included using a multi-step differential transform method (MS-DTM). The present simulations provide an interesting insight into complex fluid/thermal/species diffusion characteristics in the boundary layer region of relevance to working MHD generator systems.

Viscous flow over a nonlinearly stretching sheet

Role of relativistic knowledge in intelligent tutoring

Estimation of MHD boundary layer slip flow over a permeable stretching cylinder in the presence of chemical reaction through numerical and artificial neural network modeling

On laminar hydromagnetic mixed convection flow in a vertical channel with symmetric and asymmetric wall heating conditions

Analytical solutions for hydromagnetic natural convection flow of a particulate suspension through isoflux–isothermal channels in the presence of a heat source or sink

This work compares a number of CFD transient models of an impinging jet with both LES and URANS models. The specific case considered is that of an impinging jet with H/D = 6 and Re 23000. The study spans over a wide number of variables for the purpose to access and directly compare different approaches. The variables tested are: turbulence model (LES Smagorinsky, standard low Reynolds k-e and V2F), numerical discretization schemes, mesh density (total cell number and local cell distribution), synthetic turbulence inlet fluctuations. The model assessment is based on the comparison with available experiments for wall heat transfer and flow turbulent quantities. The computational cost is also considered for completeness.

A novel method for measuring the thermal conductivity of an electrical conductor is described. The heat flow is radial, giving important advantages for high-temperature studies. It is an electrical method and is, therefore, most suited to resistive materials which have a high temperature coefficient of resistance, such as semiconductors. Since the outside temperature of the sample need not be determined directly, and the sample is best kept thin, the method holds promise for studies of liquids, especially where convection problems have occurred in the past. In many of these aspects, the proposed method works best where the conventional axial guarded heat flow method fails.

The thermal conductivity of SX-5 graphite