scholarly journals Effects of Quartzite on the Desiccation Cracks of Clayey Soils Exposed to Wetting-Drying Cycles

2022 ◽  
Vol 11 (01) ◽  
pp. 31-34
Author(s):  
Necmi Yarbaş ◽  
Ekrem Kalkan

The compacted clayey soils crack on drying because of their high swelling potential, and their hydraulic conductivities increase. To solve this problem, it is essential to stabilize the clayey soils using additive materials. The aim of this study is to examine the suitability of quartzite as a stabilization material to reduce the development of desiccation cracks in compacted clayey liner and cover systems. Experimental study was conducted to investigate the effect of wetting-drying cycles on the initiation and evolution of cracks in compacted clayey soils. For experimental studies, seven samples were prepared stabilized by using 0%, 2.5%, 5%, 7,5%, 10%, 12,5% and 15% quartzite and then they were subjected to four subsequent wetting-drying cycles. The results show that quartzite decreases the development of desiccation cracks on the surface of compacted samples. It is concluded that quartzite as a geological material can be successfully used to reduce the development of desiccation cracks in compacted clayey liner and cover systems exposed wetting-drying cycles.

2021 ◽  
pp. 63-67
Author(s):  
I.I. Khusnitdinov ◽  

Purpose. Еxperimental substantiation of the effectiveness of biocompatible biodegradable hydrogels based on hyaluronic acid and chitosan succinate as a carrier of ranibizumab in antiglaucoma operations. Material and methods. Hydrogel drainage (HD) was obtained immediately before surgery. A solution of ranibizumab (0.23 ml) was mixed with a solution of hyaluronic acid dialdehyde (0.5 ml), then a solution of chitosan succinate (0.5 ml) was added. Experimental studies were performed in 12 (12 eyes) healthy rabbits. The first group consisted of 6 eyes – 0.187 ml of ranibizumab per 1 ml of gel. In the control group, HD was used intraoperatively without the addition of ranibizumab (6 eyes). Morphological studies were performed on 7th, 21st, and 42nd days. Results. In experimental studies in vitro and in vivo, it was proved that ranibizumab, administered as a part of 0.1 ml of hydrogel drainage in the antiglaucoma surgery area is released within 3 weeks and suppresses vascularization, scarring of the operating area, and preserves the intrascleral cavity. The optimal concentration of ranibizumab was selected-0.02 ml in 0.1 ml of gel. Conclusion. The safety and effectiveness of the use of hydrogel drainage with ranibizumab based on hyaluronic acid dialdehyde and chitosan succinate in anti-glaucoma operations has been proven. Key words: experimental research, hydrogel drainage, ranibizumab, glaucoma surgery.


2021 ◽  
Vol 14 (4) ◽  
pp. 1-24
Author(s):  
Sushant Kafle ◽  
Becca Dingman ◽  
Matt Huenerfauth

There are style guidelines for authors who highlight important words in static text, e.g., bolded words in student textbooks, yet little research has investigated highlighting in dynamic texts, e.g., captions during educational videos for Deaf or Hard of Hearing (DHH) users. In our experimental study, DHH participants subjectively compared design parameters for caption highlighting, including: decoration (underlining vs. italicizing vs. boldfacing), granularity (sentence level vs. word level), and whether to highlight only the first occurrence of a repeating keyword. In partial contrast to recommendations in prior research, which had not been based on experimental studies with DHH users, we found that DHH participants preferred boldface, word-level highlighting in captions. Our empirical results provide guidance for the design of keyword highlighting during captioned videos for DHH users, especially in educational video genres.


Author(s):  
A. L. Lebedev ◽  
I. V. Avilina

Experimental study of kinetics of dissolution of hypso anhydrites at 25 ᵒC made it possible to formulate model of the process in the form of a balance equation for the kinetics of dissolution of gypsum, anhydrite (first and second orders, respectively) and kinetics of precipitation of gypsum (second order). The processing of the experimental data were carried out on the basis of the solution of the Riccati equation. When taking into account the common-ion effect on the solubility of gypsum and anhydrite, the calculated values turned out to be more comparable with the experimental ones.


2021 ◽  
Vol 58 (4) ◽  
pp. 55-68
Author(s):  
F. Capligins ◽  
A. Litvinenko ◽  
A. Aboltins ◽  
E. Austrums ◽  
A. Rusins ◽  
...  

Abstract The paper presents a study of the chaotic jerk circuit (CJC) employment capabilities for digital communications. The concept of coherent chaos shift keying (CSK) communication system with controlled error feedback chaotic synchronization is proposed for a specific CJC in two modifications. The stability of chaotic synchronization between the two CJCs was evaluated in terms of voltage drop at the input of the slave circuit and the impact of channel noise using simulations and experimental studies.


2021 ◽  
Vol 64 (10) ◽  
pp. 728-735
Author(s):  
I. A. Rybenko ◽  
O. I. Nokhrina ◽  
I. D. Rozhikhina ◽  
M. A. Golodova ◽  
I. E. Khodosov

The article presents results of theoretical and experimental studies of the processes of iron solid-phase reduction from an iron-containing concentrate obtained as a result of hydrometallurgical dressing of ferromanganese and polymetallic manganese-containing ores with coals of grades D (long-flame) and 2B (brown). The method of thermodynamic modeling using TERRA software complex was used to study the reducing properties of hydrocarbons by calculating equilibrium compositions in the temperature range of 373 - 1873 K. The authors obtained the dependences of compositions and volume of the gas phase formed as a result of the release of volatile components during heating on the temperature for the coals of the grades under consideration. As a result of thermodynamic modeling, the optimal temperatures and consumption are determined, which ensure the complete iron reduction from an iron-containing concentrate. The results of experimental studies were obtained by modern research methods using laboratory and analytical equipment, as well as methods of statistical processing. Results of the coals analysis carried out using the Setaram LabSys Evo thermal analyzer showed that the process of thermal decomposition of coals of the studied grades proceeds according to general laws. The process of thermal decomposition of long-flame coal proceeds less intensively than of brown coal. The results of an experimental study of the processes of thermal decomposition of reducing agents have shown that volumes of the gas phases, formed when coals are heated to a temperature of 1173 K in an argon atmosphere, practically coincide with the calculated values. As a result of thermodynamic modeling and experimental study, the optimal consumption of D and 2B grades of coal is determined at a temperature of 1473 K. The best reducing agent with a minimum specific consumption is long-flame coal of D grade. When determining the optimal amount of reducing agent in charge mixtures during the study of metallization processes, it was found that with an excess of reducing agent, it is possible to achieve almost complete extraction (98 - 99 %) of iron from the concentrate.


2021 ◽  
Vol 2057 (1) ◽  
pp. 012041
Author(s):  
V I Valiullina ◽  
A I Mullayanov ◽  
A A Musin ◽  
L A Kovaleva

Abstract Experimental studies of the gravitational deposition of a polydisperse water-in-oil emulsion under heat influence are carried out. When the rate of thermal convection exceeds the rate of precipitation, partial delamination of the emulsion is found to occur. The viscosity of the dispersion medium decreases with increasing temperature, which contributes to an increase in the deposition rate of water droplets in the emulsion. In the presence of a temperature difference, convective flows occur in the liquid, while the drops of the emulsion coagulate and form larger agglomerates that settle faster to the bottom of the cell.


2019 ◽  
Vol 20 (2) ◽  
pp. 292-308
Author(s):  
V. Chernov ◽  
Е. Golomisyuk ◽  
Р. Evseev

The features of the expert study of traces from the effects of foreign objects on the inner surfaces of the cylinder mechanisms are considered. With the trasological examination of locks, most experts after examining the external and internal surfaces of the cylinder mechanisms of locks, unlocked by various types of keys, falsified or selected keys, ambiguously understand the mechanism of their trace formation, which can sometimes lead to a false conclusion. The purpose of the work is to present the results of the investigation of the mechanism of trace formation and localization of signs of exposure of foreign objects (lock pick, selected or fake keys) on the internal surfaces of the cylinder mechanisms of locks and recommendations to forensic experts in drawing conclusions during the course of the Trasological research. The mechanism of trace formation is considered, the characteristic and classification of traces of exposure to foreign objects are provided (lock pick, selected or fake keys). Groups of lock pick are identified, which are most often found in the Commission of criminal offenses, for their further research. A number of experimental studies have been carried out to study and analyze the mechanism of trace formation, as well as to localize the signs of influence of certain groups of lock pick on the internal surfaces of the cylinder mechanisms of the lock. The progress of the experimental studies has been described in stages. The results of the research on the opening of the cylinder mechanisms of locks are presented with various types of lock pick, depending on their design features. The illustrations explain the conditions for the location of traces on the relevant parts of the cylinder mechanisms of locks from the influence of the respective groups of lock pick. The results of an experimental study are summarized and conclusions are made on the possible conditions for the mechanism of trace formation. Recommendations to judicial experts on the formulation of conclusions in the course of trasological studies of cylinder locking mechanisms are proposed.


2012 ◽  
Vol 15 (1) ◽  
Author(s):  
Simone de Rocio Senger de Souza ◽  
Marllos Paiva Prado ◽  
Ellen Francine Barbosa ◽  
José Carlos Maldonado

Several techniques and criteria are available to help conducting testing activity. The choice for one of them depends on different aspects, such as the time restrictions, ef- fectiveness of the testing criteria or the features of the program under test. In this context, the programming paradigm might influence in the testing activity cost. This paper presents the results of an experimental study to characterize and evaluate the cost and strength of structural and functional testing criteria, comparing object-oriented and procedural programming paradigms. A set of 32 programs from the data structure do- main was considered in this study. The main goals in the execution of this research were: i) to obtain initial results about the investigated questions; ii) to generate artifacts which can be used as basis to define and conduct further experimental studies; iii) to support training and teaching of software testing activity.


2013 ◽  
Vol 409-410 ◽  
pp. 668-672
Author(s):  
Yong Mei Xu ◽  
Jian Tang ◽  
Jun Han ◽  
Chu Qin Lin

Aimed at a new type of ventilation - stratum ventilation, air distributions at a breathing-zone in a model office were measured under kinds of air changes, the measure parameters in the experimental studies included temperatures, wind speeds and pollutant concentrations, based on which the thermal comfort at a breathing-zone were studied. Experimental results show that, the temperature, pollutant concentration and wind speeds in a breathing-zone under 5 times air changes are better than those under 6 times air changes. The calculating results of PMV and PPD indicate that the thermal comfort at a breathing-zone under 5 times air changes is better. The experimental study is instructive for the development of the ventilation.


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