Mortar to Repair Rammed-Earth Walls’ Surfaces: Do we still Need it?

A rammed-earth technique has been echoed worldwide due to being conceived not only as an environment-friendly method of construction but also standing as an alternative method to arguably replacing cement. The technique however shows several pitfalls. One concerns the lengthy process of curing upon erecting the rammed-earth walls due to the low process of a chemical reaction occurred throughout the curing stage. A second bias followed from the slow curing and concerns the degradation accentuated at the outer wall’s texture, particularly at the edges, due to effects of the weather cycle. These drawbacks have been observed while accomplishing a funded research project. This article has at its stake remedying the above pitfalls. A natural sandy limestone shows a low percentage of calcium carbonate needed for a cohesive mixture. The method suggested here is based on an experiment that uses minerals of the fruits’ and vegetables’ waste as a binding substance. Curing time in this method has been reduced to the half. It is also suggested here that each stage has its importance, including mixing the soil particles dry and wet, compacting the moistened soil mixture, a well-made formwork and curing, towards remedying the above pitfalls.

Experience of High-Density Polyethylene as a Binding Substance in Grinding Wheels

The possibility and efficiency of the use of high-density polyethylene as a binding substance in grinding wheels for cutting-off, as well as for finish cylindrical grinding, is researched. It is determined that: - breaking mechanical strength of such circles ensures their safe operation at maximum operating speeds of 30–35 m/sec; - the use of high-density polyethylene as a binding substance in cutting wheels is not advisable, due to intensive wear and low cutting power of these tools; - wheels for finish cylindrical grinding on the basis of high-density polyethylene and hollow spherocorundum as abrasive grains in a number of key indicators (cutting power, roughness of machined surfaces) are highly competitive with grinding wheels on a bakelite bond or are comparable to them, and significantly exceed the latter in terms of wear resistance.

Low-Molecular-Weight Chromium-Binding Substance (LMWCr) May Bind and Carry Cr(III) From the Endosome

Objectives Transferrin, Tf, the protein that transports iron as Fe(III) from the blood to the tissues via endocytosis, is believed to also transport chromium(III), Cr(III). Under physiological conditions, Tf binds and releases Cr(III) rapidly; however, whether Cr(III) released from Tf in endosomes can be transported from the endosome before the endosome fuses with the cell membrane has been questioned. Cell culture studies have suggested a component(s) of the blood may be required for this Cr(III) transport, including potentially the metal-free form of oligopeptide low-molecular-weight chromium-binding substance, LMWCr. Methods Human serum Cr(III)2-Tf was prepared in a buffered solution at pH 7.4 (100 mM HEPES) containing 25 mM bicarbonate at 37 °C. LMWCr was isolated from bovine liver; Cr was removed from LMWCr by acidification in the presence of EDTA. To examine the release of Cr(III) from Cr(III)2-Tf, the pH of solutions of Cr(III)2-Tf and apoLMWCr were acidified from pH 7.4 to pH 5.5. After time intervals, aliquots were removed and frozen for analysis by electron paramagnetic resonance (EPR) spectroscopy, which can distinguish aquated Cr(III), Cr(III) bound to the two metal binding sites of Tf, and Cr(III) bound to LMWCr. Results The acidification of solutions of Cr(III)2-Tf and apoLMWCr in 100 mM HEPES and 25 mM bicarbonate solution, pH 7.4 to pH 5.5 resulted in a loss of Cr(III) from the N-terminal lobe of Tf with a t1/2 of 41 min, a ten-fold decrease from the t1/2 in the absence of apoLMWCr. Including simple chelating ligands such as citrate, ascorbate, or EDTA instead of apoLMWCr, only results in a 2-fold decrease. For loss of Cr(III) from the C-terminal lobe of Tf, inclusion of apoLMWCr resulted in a t1/2 of 1.8 minutes, a 3-fold decrease, while simple chelating ligands had no effect on the rate of Cr(III) loss. Released Cr(III) bound faster to apoLMWCr than to the chelating ligands. Conclusions The results suggest apoLMWCr has a unique effect in accelerating the loss of Cr(III) from Cr(III)2-Tf. LMWCr, which carries Cr(III) from the tissues to the urine for elimination from the body, may play a role in the removal of Cr(III) from Cr(III)-Tf and the transport of Cr(III) in endosomes into cells. Funding Sources The University of Alabama Bioinorganic Chemistry of Chromium Research Fund.

О влиянии анизотропной проводимости углекомпозитных материалов на параметры рупорной антенны C-диапазона

The influence of anisotropic conductivity of composite materials used in the manufacture of antennas on the parameters of antenna-feeder microwave devices has been considered. To test experimentally the possibility of such an effect, horn antennas of the L– and C– frequency bands were created from carbon-composite materials of various structures with a graphene-containing epoxy-binding substance. The study of the polarization characteristics of these antennas showed that the presence of anisotropic conductivity of the walls of the waveguide part of horn antennas made of composite materials leads to a change in the parameters of the antennas, which is more noticeable for high –frequency C-band antennas.

Functions of Portland Cement Ingredients with Benefits and Limitations

Cement industry plays a fundamental role in the development and improvement of India. It is binding substance required while building something. In this paper we are discussing various types of ingredients and the ratio of these ingredients that are be used in Portland cement. In this paper we also discussing about the functionality of these ingredient.

Study on the Granulation of FLY Ash from Thermal Power Station

The effect of the type and amount of binding substance on the yield and strength of granules prepared from fly ash was studied. The highest yield of granules was achieved with clayish slip used as binder. The granules obtained are brittle, with compression strength 0,1МРа. The apparent density of the sintered granulates was in the range1200-1500kg/m3 and the total porosity was 55-40%.