REDUCING THERMAL INERTIA TO IMPROVE THERMAL COMFORT BY CONFIGURATION OF A NEW BRICK

Climate change has changed seasons, affecting the indoor temperature of buildings and causing a strong feeling of discomfort, especially in hot weather. This feeling of discomfort is mainly due to thermal inertia. The aim of this work is to reduce the indoor temperature of buildings by using a new brick with a low thermal inertia. As part of this work we have designed a brick with the same characteristics as the ordinary ones but which are perforated so that in the construction of the wall they form a conduit for the transport of air. The latter thus acts as a heat transfer fluid in its upward convective movement, bringing with it the heat stored in the wall. In order to improve thermal exchange, an air-extractor roller system has been installed. This air extractor allows to increase convection in the walls, reducing thermal inertia and implicitly improving thermal comfort.

СОЗДАНИЕ И ИССЛЕДОВАНИЕ ГЕЛИОТЕХНОЛОГИЧЕСКОЙ УСТАНОВКИ С ПОЛИКАРБОНАТНЫМ ПОКРЫТИЕМ

The proposed solar dryer (S / D) has a polycarbonate coating, which is actually a combined dryer. By drying an agricultural products in the proposed apparatus, it is possible to get ecologically pure and high quality food. The "greenhouse effect" in S / D ensures the temperature under the glass is 15-25°C, higher than the ambient temperature. In windy weather, the product to be dried cannot be left in the open air due to strong winds, in this device drying in windy weather occurs no less intensively than in hot weather, although the air temperature in S / D is not high. During wind it is recommended to locate the S / D with the inlet towards the wind. The high drying speed occurs due to the increased convective movement. The wind creates a fan effect both at the inlet S / D and at the outlet - at the end of the pipe. In the proposed installation, it is possible to dry various agricultural products, both in direct sunlight and without them.

DETERMINATION OF THE NATURE AND SPEED OF CONVECTIVE FLOWS IN THE PHYSICAL SIMULATION OF THE PROCESS OF SOLIDIFICATION OF INGOTS

The paper describes in detail the application of the shadow method for physical modeling of the solidification process of large ingots, for visualizing and quantifying convective flows. As a result of the experiment, the proposed method allowed to visualize convective flows during casting and solidification of the model ingot. At the end of casting, the flows are represented as a vortex movement, as the further solidification of the flow changes to a more uniform appearance, they have a laminar appearance, while their visualization deteriorates. In the initial moments of time, the rate of descending flows is higher than the rate of ascending ones. Further, as the solidification continues, the rate of descending flows decreases, and the rate of ascending flows increases. The results obtained are in good agreement with the literature data, as well as with industrial experiments, which makes it possible to consider this method of studying the convective movement of a liquid in an ingot appropriate.

Study on Diffusion Coefficient of Fluorophores in 3D Hydrogel with Cationic Charge using Microchip

The diffusion coefficients of ions are measured in a microchip filled with a cationic charged 3D hydrogel in order to study the effect of cationic charged 3D hydrogel on the diffusivity of ions. In this study, poly-diallyl-dimethyl-ammoniumchloride (poly-DADMAC) is used to produce a 3D hydrogel. Four different fluorophores are used in the 3D hydrogel rhodamine 6G, rhodamine-BSA, fluorescein isothio-cyanate (FITC) and FITC-BSA. The rhodamine 6G and rhodamine-BSA are positively charged (cations), while fluorescein isothio-cyanate (FITC) and FITC-BSA are negatively charged (anions). Two widely used techniques which are short time diffusivity measurement technique and long time diffusivity measurement techniques are used to measure the diffusion coefficients. For the short time measurement, Fluorescence recovery after photo-bleaching (FRAP) is used by a 3D confocal microscope. For the long time measurement, fluorescence images are taken for 11 days to observe a pure diffusivity without any convective movement. As a result, the diffusivity of the cations was found to be lower than that of the anions in the cationic charged hydrogel.

Analysis of a Haze Event over Nanjing, China Based on Multi-Source Data

We analyzed a June 2018 Nanjing, China haze event using ground-based and spaceborne sensors, combined with sounding and HYSPLIT backward trajectory data, with the ground-based and spaceborne sensor data exhibiting good consistency. Water vapor content showed significant positive correlation with AOD (aerosol optical depth), and AOD measured in urban and industrial areas was much higher compared to other similar zones. The afternoon convection caused the aerosol uplift during the haze event. Higher aerosol concentration was detected below 2 km. Due to the summer afternoon convective movement, pollutants at high altitude were dominated by small particles, while the overall pollutant mix was dominated by mixed aerosols. During a stable period over June 11–18, a single, near-surface inversion layer, and occasional two inversion layers, stopped pollutant dispersal, with only very stable ocean air mass transport in the southeast direction available. The Air Quality Index drop which took place during June 28–30 was caused by two inversion layers, combined with the immigration of pollutants from inland air masses.

Dimensional Analysis of Grid Pattern on a Nematic Liquid Crystal

Grid pattern (GP) was observed on planarly aligned nematic liquid crystal 4-methoxy-benziledene-4-n-buthyl-aniline (MBBA) when it applied by certain frequency and certain voltage which exceeds a threshold voltage, VGP. The GP appeared due to convective movement of MBBA molecules. Dimensions on GP were distinguished into length and width of GP rectangular shape. Width-area of GP is product of the length and the width. Dimensional analysis carried on image processing used ImageJ software. Observation on the pattern showed that the frequency affected GP dimensions, which were proportional to the GP length and inversely proportional to the GP width. Variation on frequency also showed that the frequency was inversely proportional to GP width-area that formed on image, but was proportional to sample thickness.

OXYGEN TRANSPORT AND UTILIZATION: AN INTEGRATION OF THE MUSCLE SYSTEMS

Exercise offers a unique stage from which to study and teach the integration of physiological systems. In this article, the process of matching O2 transport from air to its ultimate consumption in the contracting cell is utilized to integrate the workings of the cardiac, smooth, and skeletal muscle systems. Specifically, the physiology of exercise and the maximal oxygen consumption (V˙o2 max) achieved through the precise linking of these three muscle systems are utilized to highlight the complexity and importance of this integration. Smooth muscle plays a vital “middleman” role in the distribution of blood-borne O2 to the appropriate area of demand. Cardiac muscle instigates the convective movement of this O2, whereas skeletal muscle acts as the recipient and ultimate consumer of O2 in the synthesis of ATP and performance of work. In combination, these muscle systems facilitate the remarkable 15- to 30-fold increase in metabolic rate from rest to maximal effort in endurance-type exercise.

Experimental Study of Heat and Mass Transfers at the Interface of Solidification of a Binary Solution

This paper deals with the experimental analysis of the influence of thermohaline natural convection on phase change liquid-solid of multicomponent mixtures. We present solidification experiments (dendritic front) from a horizontal plane heat exchanger placed in a cavity filled with a binary NH4Cl-H2O mixture. The solid grows simultaneously on the upper and lower faces of the exchanger and permits the study of two simultaneous configurations. We qualitatively study phenomena met in the presence of thermohaline convection in the liquid phase (cooling from the top) and we analyze in detail the case of the growth without convective movement in the liquid phase (cooling from the bottom). Thus, coupled effects of salt rejection and solid fraction on the front kinetics are examined by measurements of the front temperature and solid fraction. A simple model confirms the weak role played by these two phenomena for the range of characteristic parameters studied. Two conflicting effects of the solid fraction are nevertheless put in evidence.

Energy Separation in a Jet Flow

Fluids in motion can separate into regions of higher and lower energy (temperature); this is called “energy separation.” The present study concerns the mechanism of energy separation in a free, circular, air jet, including the effects of acoustic excitation. Starting with the initial energy separation occurring in the boundary layer inside the nozzle, the energy separation in a jet begins to be affected by the action of vortices from an axial location, measured from the jet exit, of about 0.3D (D is the diameter of nozzle exit), becomes intensified at about 0.5D, begins to be diffused from about 1D, and there is no discernible energy separation at about 14D. The entrainment of the ambient fluid considerably affects the energy separation, and its effects appear at axial locations between about 6D and 8D. The present definition of the energy separation factor renders its distribution independent of the jet Reynolds number; except for axial locations between about 0.3D and 4D. The development of energy separation in the region close to the nozzle exit is faster when the jet Reynolds number is higher. Acoustic excitation not only enhances the energy separation, but also accelerates its diffusion. This effect is greatest for axial locations between about 1D and 4D. The fact that the acoustic excitation has a strong effect on the vortex structure and the energy separation provides good evidence that the convective that the convective that the convective movement of vortices is the cause of energy separation in jets.