Investigation of the Load-Carrying Capacity of Barretes for a 56-Storey Residential Building

Soil Mechanics and Foundation Engineering - We present the results of full-scale tests of barretes in the area of future building of a 56-storey residential building in Moscow. These tests were...     

Controlling the microporosity of SBA-15 silicate material by background salt solution

The structure of silicate material of the SBA-15 type has been studied under variable composition of a salt solution in synthesis. Ammonium and sodium chlorides, as well as ammonium fluoride, introduced into the composition of the reaction mixture both at the first stage of precipitation and at the second stage of the thermal treatment (TT), have been used as the salt additives. The mesostructure was controlled by X-ray diffraction, gas adsorption and transmission electron microscopy. It was found that the multiple increase of the ionic strength of the solutions in the presence of chloride salts disrupt the stoichiometry of the silicate-surfactant interaction at the first stage of formation of mesostructure and leads to the formation of an impurity of irregular structure. The ions of ammonium promote an increase in the microporosity of the silicate wall. The presence of sodium ions reduces microporosity. Small quantities of fluoride ions (F^?: Si = 0.032) improve the ordering of the product at the stage of primary precipitation. At the ratio F^?: Si = 0.16, the hexagonal mesostructure is not formed. The introduction of fluorides at the TT stage leads to a decrease of the silicate pore wall thickness, microporosity and hexagonality of the pore.     

Changes in the mesostructure and properties of MCM-41 depending on the formation medium

Changes in the mesostructure and hydrothermal stability of the MCM-41 silicate material, depending on the synthesis conditions have been investigated. The mesostructure was characterized by the X-ray structural analysis, adsorption surface measurements, and hydrothermal stability. Changes in the synthesis conditions consisted in changing the reaction solution basicity using ammonia and alkali and replacing the mother liquor used in hydrothermal treatment by water, as well as salt and alcohol-ammonia solutions. The increase of the pore diameter is caused, as a rule, by the water osmotic pressure. Moreover, if the silica polycondensation is slowed or sterically hindered, the pores acquire a hexagonal shape or, under conditions promoting polycondensation, a cylindrical one. Predominance of the hexagonal shape over the cylindrical one points to the reduced hydrothermal stability of the material. Pore wall consists of two-layer silica pack with thickness of 0.08–0.10 nm. Ammonia applying, as reaction medium basicity factor, provides maximal silica polymerisation rate and hight hydrothermal stability of the material.     

Small signal frequency response studies for plasma electrolytic oxidation

Plasma assisted electrochemical treatments provide new possibilities in surface modification of various materials including light weight alloys. However, their large-scale application is still restricted, mainly due to poor understanding of the process mechanisms and consequent limitations in process control and automation. This problem can be resolved if the frequency response (FR) of the system is known and applied for process diagnostics. Our previous work has shown the effectiveness of the large signal mode for FR studies of plasma electrolytic oxidation (PEO) of aluminium. This research is dedicated to FR measurements during PEO of Al in the small signal mode corresponding to small perturbations of voltage signal around large DC values. The study was carried out during PEO of Al at DC voltages which were varied from 450 to 600 V. The FR obtained is a frequency dependent admittance of the PEO electrolyser; this complex number is represented by a modulus and a phase angle. Under potentiostatic conditions, the modulus evolution strongly correlates with the average current value; therefore, it bears insufficient amounts of independent information. The FR phase angle measured within this study was never obtained before. Depending on the frequency, it varies between 0° and 70 ° in the capacitive domain. One of the most notable features of this characteristic is low values at 500-5000 Hz when microdischarges appear during PEO. The other feature is a correlation with the coating growth. As a result, a new diagnostic tool was developed and shown to be effective for evaluation of microdischarges and surface properties during the treatment, thus decreasing the uncertainty in the system.     

Conducted IEMI threats for commercial buildings

While most of the emphasis has been focused on the radiated threat represented by intentional electromagnetic interference, it is clear that the threat from conducted disturbances should not be neglected. Conducted threats include those that are produced by the cable coupling of radiated fields and from the direct injection of conducted disturbances into the wiring of a building. It is well known that in the majority of cases, cables provide the most efficient means of transporting potentially damaging energy into equipment. The first part of this paper describes how electrical disturbances can impact electronic equipment inside a building through the power and earthing circuits. Measured data are summarized to illustrate how electrical signals propagate through the power and earthing circuits from the outside to the inside and what levels of signals create problems with electronic equipment. With this understanding of the impact of transient waveforms on electronic equipment and how these disturbances can propagate throughout a building, calculations are then used to evaluate different types of conducted threats to buildings.     

The problems of present-day enterology

The European Union has a formal interest in public health under the Article 129 of the Maastricht Treaty. Hitherto, the main contribution of the European Union action in public health has been limited to research, health information and education concerning, in particular major diseases and drug dependence. Unfortunately the European architects did not clearly conceive a plan for the establishment of a common health policy despite the fact that the European health policies are fragmented and are often the indirect results of economic policies. Indeed, the domain of public health is essentially governed by the principle of national sovereignty, onto which the principle of subsidiarity has been grafted. Whereas Article 129 of the Maastricht Treaty applies especially to preventive health policies, the concomitant affirmation of the principle of subsidiarity in this field tends to suspend any establishment of a European health policy. In the same way, the lack of compulsory provisions relating to Community actions, expressed as recommendations, raises the question whether the European Union is willing to move to a European health policy.