LAB-SCALE EXPERIMENTS FOR SOIL CEMENTING THROUGH BIO-CHEMICAL PROCESS

Ureolytic bacteria strains of Bacillus show its ability of calcium carbonate precipitation through metabolic activity. Different studies related to self-healing concrete material were reported associated with the generated calcium carbonate of Bacillus subtilis HU58 metabolism in recent communications. In this paper, recent findings of soil cementing with a combination of such precipitated products were presented. The experiments relied on the lab-scale studies with the use of sand-clay mixture as the controlled soil specimens. Bacillus bacteria and nutrients were mixed to introduce in the sand matrix and then curing in high moisture condition. The composition and morphology of soil specimens were characterized after solidifying by FTIR, XRD, and SEM. Water percolation and mechanical stability for the physicomechanical properties were also tested with the unconventional method. Discussing the relevant results can help to figure out the next experiments in the field of geotechnical engineering. From the perspective of this study, the sustainability factor should be considered to apply this promising technique for soil stabilization and improvement and/or for the formulation of bio-brick as an alternative to sintered clay-based brick. From the perspective of this study, this technique for soil stabilization and improvement and/or for the formulation of bio-brick can be considered a promising sustainable alternative to sintered clay-based brick.

The Problem of Halitosis in Prosthetic Dentistry, and New Approaches to Its Treatment: A Literature Review

The aim of this work is a review of recent information about halitosis among patients using prosthetic dentures. Halitosis is a condition in which an unpleasant smell comes out of the oral cavity, which is caused mainly by volatile sulfur and non-sulfured compounds. The etiology of halitosis may be intra- or extra-oral; in most patients, however, it is due to the activity of microorganisms in the oral cavity. The problem of the occurrence of halitosis has accompanied patients for many years. In dental prosthetics, the problem of halitosis occurs in patients using removable or fixed dentures. In both cases, new niches for the development of microorganisms may be created, including those related to halitosis. It should be noted that dentures—both fixed and removable—are a foreign body placed in the patient’s oral cavity which, in case of insufficient hygiene, may constitute a reservoir of microorganisms, causing this unpleasant condition. Conventional treatment of intraoral halitosis reduces microbial activity via chemical and/or mechanical action. Currently, the search for new strategies in the treatment of halitosis is in progress. One idea is to use photodynamic therapy, while another is to modify poly(methyl methacrylate) (PMMA) with silver and graphene nanoparticles. Additionally, attempts have been made to combine those two methods. Another unconventional method of treating halitosis is the use of probiotics.

Biographical method for analyzing the results of the application of the technological model of accompanying adolescents registered in juvenile affairs departments

In the introduction, the problem of the competence of the inspector for juvenile affairs when conducting preventive measures with registered adolescents is updated. One of the options for organizing effective preventive measures based on the Technological model of pedagogical support for registered adolescents is proposed. The article describes an unconventional method used by the PD inspector in working with a teenager, the method of prevention "express smartphone control". The purpose of this article is to describe examples of the implementation of a Technological model of pedagogical support for adolescents registered in juvenile affairs departments, which led to a successful change in value attitudes in their worldview. The consequence of the change was the moral choice when the teenager realized himself in society five, ten, fifteen years after the preventive work carried out according to the developed model. In the main part of the article, through the biographical method of research, specific examples are presented that were the result of the use of a Technological model of accompanying adolescents who are registered in juvenile affairs departments. The conclusion of the article contains a generalizing conclusion based on the results of the application of the Technological Model of pedagogical support for adolescents registered in juvenile affairs departments.

THE DEPENDENCE OF THE COEFFICIENT OF EFFICIENCY (CE) OF THE HEATING INSTALLATION “EFI” UPON THE INITIAL TEMPERATURE OF THE HEAT-CARRYING AGENT

The purpose of the study is to determine the increase in the efficiency of the electrophysical ionization device on a scientific basis, which produces thermal energy based on the regularity of the electrophysical ionization process. This research article discusses the dependence of the amount of thermal energy obtained in the device of electrophysical ionization on temperature. It is noted that if in the case of the traditional method of heating the substance used in the heating industry, the relative heat capacity of the substance is important, then when heated by an unconventional method, in other words, the temperature of the substance is important in the electrophysical ionization device. This indicator, determined on the basis of the experiment, emphasizes the need to apply depending on the correct choice of the physical parameters of the substance the electrophysical ionization method for the efficient production of thermal energy in the heating industry from the heat-carrying substance. Although the heating of water is mainly carried out using various well-known traditional and non-traditional methods, the natural law of heating water is unique. This law notes the dependence of the magnitude of changes in the internal energy of water in a certain volume of heated water and on the speed of movement of this mass. Considering from the point of view of the regularity of the above direction, it is noted that in order to compare the water heated by the traditional method, appropriate calculations have been made.

Characteristics of Porous Aluminium Materials Produced by Pressing Sodium Chloride into Their Melts

The paper deals with research related to the production of metal cellular aluminium systems, in which production is based on the application of sodium chloride particles. In this paper, the properties of porous aluminium materials that were produced by an unconventional method—by pressing salt particles into the melt of aluminium alloy—are described. The new methodology was developed and verified for the production of these materials. The main feature of this methodology is a hydraulic forming press and a simple-shaped foundry mould. For these purposes, four different groups of sodium chloride particle sizes (1 to 3, 3 to 5, 5 to 7 and 8 to 10 mm) were applied. The preferred aluminium foundry alloy (AlSi12) was used to produce the porous aluminium samples. Based upon this developed methodology, samples of porous aluminium materials were produced and analysed. Their weight and volume were monitored, their density and relative density were calculated, and their porosity was determined. In addition, the porosity of samples and continuity of their air cells were monitored as well. An industrial computed tomograph and a scanning electron microscope were applied for these purposes.

An Unconventional Method for the Diagnosis and Study of Generator Rotor Thermal Bows

The rotor thermal sensitivity often affects the dynamic behavior of power unit generators. Owing to this phenomenon, increments of field current and other process parameters that are related to it may cause a shaft thermal bow and significant changes in the synchronous vibration. This symptom can also be caused by many other common malfunctions that affect rotating machines. Therefore, diagnostic techniques aimed at identifying the actual fault are very useful for optimizing maintenance activities. The thermal sensitivity of generator rotors can be deemed as a fault because it is commonly caused by a local deterioration of the winding insulation as well as by jamming phenomena between conductors and rotor slots, caused by friction forces due to the different thermal expansions of these components. This paper shows the results obtained applying a diagnostic method, based on multiple linear regression models, which has been developed for the analysis of generator vibrations caused by thermal sensitivity. Nevertheless, non-linear relationships between vibration and process parameters have also been taken into account. The capabilities of this diagnostic technique have been validated using the analysis of experimental data collected in a power plant. The results of this investigation are shown and discussed in the paper.

An Unconventional Method for the Diagnosis and Study of Generator Rotor Thermal Bows

The rotor thermal sensitivity often affects the dynamic behavior of power unit generators. Owing to this phenomenon, increments of field current and other process parameters that are related to it may cause a shaft thermal bow and significant changes in the synchronous vibration. This symptom can also be caused by many other common malfunctions that affect rotating machines. Therefore, diagnostic techniques aimed at identifying the actual fault are very useful for optimizing maintenance activities. The thermal sensitivity of generator rotors can be deemed as a fault because it is commonly caused by a local deterioration of the winding insulation as well as by jamming phenomena between conductors and rotor slots, caused by friction forces due to the different thermal expansions of these components. This paper shows the results obtained applying a diagnostic method, based on multiple linear regression models, which has been developed for the analysis of generator vibrations caused by thermal sensitivity. Nevertheless, nonlinear relationships between vibration and process parameters have also been taken into account. The capabilities of this diagnostic technique have been validated using the analysis of experimental data collected in a power plant. The results of this investigation are shown and discussed in the paper.

Recycling of crystalline silicon photovoltaic solar panel waste to modified composite products

This investigation highlights effective technology to convert crystalline silicon photovoltaic solar panel waste to composite products. The main problem with recycling photovoltaic modules is to economically separate and extract the materials in the laminated structure. This investigation was attempted to recycle c-Si photovoltaic modules using an unconventional method in which the cumbersome process of separating the materials in the module is avoided altogether. The aluminium frame, outer glass and junction box are removed mechanically and the rest of the c-Si PV module waste is powdered and blended with recycled polypropylene (PP) and Low Density Polyethylene (LDPE) each to make compression moulded tiles. A total of six compression moulded tiles were made. Three tiles from each base material blended in three blend ratios (0%, 10% and 20%) with the powdered PV module waste. The tensile strengths of the tiles were tested and compared. The results prove that tiles made with recycled PP as a base material show very low tensile strength. However, recycled tiles made by blending with LDPE show appreciable tensile strength of more than 8 MPa. These tiles may be used to make furniture.