Design And Development Of An External Glass Wall Cleaning System

The increasing number of skyscrapers calls for an increasing demand for regular maintenance and cleaning of the large glass panes or windows of these buildings. Cleaning these windows, is not only tough and a risky job but also time consuming. Thus, an effort has been made to introduce a new system which not only reduces the human effort but also aims in cleaning the windows effectively as well as efficiently. This project aims to produce a clean view through the windows which helps in maintaining the aesthetic view of the building. This device can be used periodically for efficient cleaning of the external glass walls, as there is no involvement of a human being suspended from the top of the building. The Current device can be used as a replacement for an existing method in order to ensure safety of the workers.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. KINEMATIC AND STRESS STATES OF THE PLASTIC REGION IN CONTACT WITH THE CONICAL SURFACE OF THE MATRIX

For the extrusion of glasses with a conical bottom using the method of plastic flow by A. L. Vorontsov, the kinematic and stress states of the extruded metal in the area of the plastic deformation zone in contact with the conical surface of the matrix were determined. The results are combined with the results obtained earlier for the cylindrical region located under the forming glass wall. The resulting formulas will be used to determine the stress state in the areas of the focus located under the end of the punch. The derived formula for the maximum pressure on the matrix wall is necessary for calculating the matrix strength and making an informed decision about the need for its banding.

COMBINED EXTRUSION OF GLASSES WITH A CONICAL BOTTOM. KINEMATIC AND STRESS STATES OF A CYLINDRICAL PLASTIC REGION LOCATED UNDER THE FORMING GLASS WALL

For extrusion of glasses with a conical bottom using the method of plastic flow by A. L. Vorontsov, the kinematic and stress states of the extruded metal in the area of the plastic deformation center located under the formed wall of the glass and adjacent to the cylindrical section of the matrix were determined. The resulting formulas will be used to determine the stress state in the areas of the focus located under the punch end.

Study of load-bearing timber-wall elements using experimental testing and mathematical modelling

Combining timber and glass in the wall elements of the building envelope with the proper orientation of such transparent façade elements enables the utilization of solar energy for heating and internal illumination of the building. However, the asymmetrical layout of timber-glass wall elements in such buildings can result in problems with the horizontal stability of the structure, so their participation to load-bearing capacity of the structure is usually neglected. The study deals with solutions for such elements as horizontal load-bearing members with proper connection details. First, specifically developed timber-glass wall elements were experimentally tested under monotonic and cyclic horizontal point load, and further in combination with classical timber-framed wall elements implemented into special single and two-storey box-house models, which were further experimentally tested on the shaking table. In the second part as the main goal of the study, a quite simple mathematical model of the box-house prototypes is developed using a fictive diagonal element for simulating the racking stiffness of the bracing timber-glass wall element. The calculated results for the 1st vibration period are compared with the previously measured experimental results to prove an accuracy of the developed model. Finally, a linear time-history calculation is done as a sample presentation of the developed mathematical model using Landers acceleration spectrum. The developed mathematical model enables a simple and effective seismic response calculation of timber buildings considering the developed timber-glass wall elements as load-bearing bracing elements against horizontal load actions. The model can also be recommended for using in further parametric numerical academic studies analysing the influence of various parameters.

Simulation of Thermal Radiation and Turbulent Free Convection in an Enclosure with a Glass Wall and a Local Heater

In this study, a numerical modelling of thermal radiation and turbulent thermogravitational convection in a large-scale chamber containing a thermally-generating element is conducted. The lower border of the cabinet is maintained under adiabatic conditions, while on the other walls the convective boundary conditions (Robin boundary condition) are used. The managing equations with corresponding restrictions are transformed using the stream function–vorticity formulation and then solved by employing a finite difference method. The influence of both the height and wall emissivity of the heated source on fluid motion and the heat transmission in a large-scale chamber is investigated. Our results of the calculations on non-uniform grids with algebraic transformation are in excellent agreement with other available experimental and numerical outcomes for turbulent thermal convection in enclosures. The computations indicate that the average total Nusselt number is enhanced up to 2 times with an increase in the heater height. The results show that the surface emissivity of the heat source has a great influence on the total thermal transference coefficient. Furthermore, a growth of the heater surface emissivity has no significant effect on the flow structure.

Casimir-Polder Interaction of an Atom with a Cavity Wall Made of Phase-Change Material out of Thermal Equilibrium

We consider the out-of-thermal-equilibrium Casimir-Polder interaction between atoms of He*, Na, Cs, and Rb and a cavity wall made of sapphire coated with a vanadium dioxide film which undergoes the dielectric-to-metal phase transition with increasing wall temperature. Numerical computations of the Casimir-Polder force and its gradient as the functions of atom-wall separation and wall temperature are made when the latter exceeds the temperature of the environment. The obtained results are compared with those in experiment on measuring the gradient of the Casimir-Polder force between 87Rb atoms and a silica glass wall out of thermal equilibrium. It is shown that the use of phase-change wall material significantly increases the force magnitude and especially the force gradient, as opposed to the case of a dielectric wall.

PUNCHING CUPS WITH BOTTOM FLANGE BY DIRECT EXTRUSION WITH COUNTER-PUNCH. INDUSTRIAL TESTING AND ITS RESULTS

The results of industrial testing of a new method of manufacturing glasses with a flange in the bottom part by direct extrusion with a counter-punch are presented. The characteristics of the tools used, the geometrical parameters of the stamping, and also the lubrication are described in detail. A method for eliminating the meniscus of the end face of the extruded glass wall is described. The results of practical studies of the strength properties and hardness of billets and obtained products are presented. Additionally, the high accuracy of the obtained calculation formulas is confirmed.