Experimental Study on Thermal Performance of Pre-formed Thin Heating Floor Filled with Shaped PCM

A shape-stabilized phase change material (PCM) with high-density polyethylene was prepared as the supporting material to be added to a pre-fabricated light and dry-type heating floor. A system for underfloor heating experiments was set up in the laboratory to test the effects of average supply and return water temperatures and different temperature differences on the thermal performance of two floor heating systems under 10 different operating conditions, respectively. The results show that the surface heat-flux density of a phase change floor (PCF) is higher than that of an ordinary one at the stable stage. The proportion of heat transfer to the heating room is about 13% higher in the phase change system compared to the normal system, and the heat loss is reduced by more than 10%. At the cooling stage, the surface temperature of PCF decreases slowly, compared to the rapid decrease of the ordinary one.

Biodiversity and Climate Change

This article analyses the question of a relationship between biodiversity and climate change. The legal framework for the protection of biodiversity from climate change is contained in the climate change system of treaties, i.e. the 1992 United Nations Framework Convention on Climate Change; the 1997 Kyoto Protocol; the 2015 Paris Agreement, on one hand; and the 1992 Convention on Biological Diversity on the other. There are also important global Conventions which contribute to combating of impacts of climate change on biodiversity, such as the Desertification Convention and the Ramsar Convention. The article discusses the principle of common but differentiated responsibilities within the context of climate change and biodiversity. The case study is the Arctic, which illustrates the impact of climate change on biodiversity.

Effect of modified Ohm's and Fourier's laws on magneto thermoviscoelastic waves with Green-Naghdi theory in a homogeneous isotropic hollow cylinder

This paper deals with the modified Ohm's law, including the temperature gradient and charge density effects, and the generalized Fourier's law, including the present current density impact, the problem of conveyance of thermal stresses and temperature in a generalized Magneto–Thermo-Viscoelastic Solid Cylinder of radius L. The formulation is applied to the generalized thermoelasticity dependent on the Green-Naghdi (G-N II) hypothesis. The Laplace change system is utilized to solve the problem. At last, the outcomes got are introduced graphically to show the impact of Magnetic Field and time and on the field variables.

Dynamic Simulation Analysis on Axle Spline of High-Speed Train Gauge-Change System

Spline couplings are widely used in transmission systems to transfer torque due to their higher load carrying capacity and better durability performance. Most researches are conducted under static and quasistatic loading cases; however, very little is known about their contact behavior and stress distribution under dynamic loading cases, especially as a key transmission component between wheel and axle. In this paper, a 3D dynamic contact and impact analysis model of the wheel-axle spline of high-speed train gauge-change system is employed in order to investigate the effect of driving velocity and assembling error and vibration on spline couplings. Three categories of loading cases are considered: (i) 0.3 m/s2 driving rate representing quasistatic loading case; (ii) 0.5 m/s2 driving rate representing normal loading case, and (iii) 1 m/s2 driving rate representing exceptional loading case. Aside from this, influence of spline misalignment, including radial misalignment and circumferential misalignment, has been investigated under normal loading case. Numerical results for surface integral contact analysis conducted by LS-DYNA and MATLAB were presented and compared for the verification of the results.