Constant Electric Current Research Articles

External Factors Influence on Defects Detection by Scanning Contact Potentiometry

Scanning contact potentiometry (SCP) method was used to detect structural inhomogeneities in a welded joint under the application of heat and constant electric current. For this purpose, a special sample was prepared, welded by manual arc welding from two halves of X8CrNiTi18-10 (Chromium-Nickel-titanium stainless Steel) austenitic steel, each with dimensions of 200×110×13.5mm. After welding, welded sample was inspected using X-ray radiography. The sample was stored for five months at room temperature, and the sample surface was scanned using different scanning speed ranging from 0.36 to 1.8 mm/sec. It was found that when scanning speed was increased, the signal values remained the same. In another experiment, a constant electric current was passed through the sample from 0.01 to 0.1A. Applying current led to the excitation of weak structural inhomogeneities from the welding joint butt, although it was machined. While heat led to an increase in diagnostic signal amplitude.

Theoretical and practical aspects of the mathematical description electrochemical purification of oil-contaminated soil

Abstract The electrochemical method is one of the most promising solutions for oil-contaminated soil remediation by passing small constant electric currents. The creation of installations for the electrochemical treatment of oil-contaminated soils requires an understanding of the ongoing processes, which can be achieved by developing a mathematical model. In this paper, we consider obtaining a mathematical description of the change of the oil pollution concentration from the time of direct current treatment and the distance to the electrodes, followed by experimental verification of the adequacy of the models to real electrochemical processes in oil-contaminated soils. The article shows the main approaches and stages of obtaining mathematical models for assessing the cleaning effectiveness. Mathematical models of pollutant concentration changes of the depending on the time and distance to the electrodes were obtained. A correlation between the most important design parameters of the installation and the parameters of the electrochemical process has been established. The resulting models can be used to design installations for electrochemical treatment of oil-contaminated soils.

Exploring the frontiers of neurostimulation: The role of transcranial direct current stimulation in modern neuroscience

ABSTRACT Introduction: Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that has gained significant interest in both clinical and research settings. It involves applying a low, constant electrical current to the scalp to modulate neuronal activity. tDCS is valued for its cost-effectiveness, portability, and simplicity compared to other brain stimulation methods such as transcranial magnetic stimulation (TMS). This article explores the historical context, mechanisms, and clinical applications of tDCS, highlighting its potential in treating neurological and psychiatric disorders and enhancing cognitive functions. Objectives: The noninvasive brain stimulation method known as tDCS has drawn a lot of attention in both clinical and scientific contexts. To alter neuronal activity, a low, steady electrical current is applied to the scalp. When compared to other brain stimulation techniques such as TMS, tDCS is prized for its affordability, mobility, and ease of use. The historical background, workings, and clinical uses of tDCS are examined in this article, with an emphasis on how it may be used to cure mental and neurological conditions as well as improve cognitive abilities. Methods: tDCS, a noninvasive brain stimulation technique, has garnered significant interest in both clinical and scientific settings. A low, constant electrical current is given to the scalp to change neural activity. tDCS is valued for its cost, portability, and simplicity of usage in contrast to other brain stimulation methods such as TMS. This article explores the history, mechanism, and clinical applications of tDCS, focusing on its potential for treating neurological and mental disorders and enhancing cognitive function. Results: Participants’ depression levels significantly decreased, according to the study. By the end of the intervention, over 50% of the participants had responded, and at the 1-month follow-up, this percentage had risen to almost 77%. Only minor, self-limiting adverse effects, such as tingling and soreness at the stimulation site, were experienced during the well-tolerated treatment. These results show that tDCS is effective in treating depression and is in line with international research. Conclusion: The tDCS significantly reduces depression symptoms and is a well-tolerated and successful supplementary treatment for treatment resistant depression. The study encourages more research into the therapeutic uses of tDCS, especially for people who do not react to conventional antidepressant drugs. Notwithstanding the encouraging outcomes, the study admits its shortcomings, including its limited sample size and lack of a control group. To maximize the use of TDCS in clinical practice, future studies should concentrate on maintenance procedures, long-term effects, and customized treatment strategies.

Exploring the Differential Effects of Transcranial Direct Current Stimulation: A Comparative Analysis of Motor Cortex and Cerebellar Stimulation

BackgroundTranscranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation technique. Constant electric current is passed through the patient's scalp with the aim of modulating cortical excitability. Stroke is a cerebrovascular disease characterized by hemorrhage or cerebral ischemia. This systematic review and meta-analysis are aimed at comparing the efficacy of motor cortex stimulation with that of cerebellar stimulation by using transcranial direct current stimulation. MethodGoogle Scholar, PubMed, EMBASE, Cochrane CENTRAL, and Physiotherapy Evidence Database (Pedro) databases were searched for studies. The extracted qualitative data was synthesized systematically. Cochrane RevMan software was used to conduct a meta-analysis of quantitative data. The fixed effects mean difference of the collected data was calculated at a 95% confidence interval (CI) for the changes in balance and side effects. ResultsThis research included 10 articles with seven studies assessing changes in balance (outcome measured in CoP and FMA scores) and side effects (tingling and itching were the most prevalent). There was no significant difference between the efficacy levels of m1-tDCS versus ctDCS (P = 0.18), m1-tDCS versus sham (P = 0.92), and ctDCS versus sham (P = 0.19). Itching and tingling sensation were the most common and were significantly prevalent in sham interventions (P < 0.00001). ConclusionWe found that motor cortex and cerebellar stimulations are both effective in improving motor function in stroke patients. There are no adverse effects to using the interventions besides mild itching and tingling experienced during the stimulation.

Electrostimulable polymeric films with hyaluronic acid and lipid nanoparticles for simultaneous topical delivery of macromolecules and lipophilic drugs.

This study focused on developing electrically stimulable hyaluronic acid (HA) films incorporating lipid nanoparticles (NPs) designed for the topical administration of lipophilic drugs and macromolecules. Based on beeswax and medium-chain triglycerides, NPs were successfully integrated into silk fibroin/chitosan films containing HA (NP-HA films) at a density of approximately 1011 NP/cm2, ensuring a uniform distribution. This integration resulted in a 40% increase in film roughness, a twofold decrease in Young's modulus, and enhanced film flexibility and bioadhesion work. The NP-HA films, featuring Ag/AgCl electrodes, demonstrated the capability to conduct a constant electrical current of 0.2mA/cm2 without inducing toxicity in keratinocytes and fibroblasts during a 15-min application. Moreover, the NPs facilitated the homogeneous distribution of lipophilic drugs within the film, effectively transporting them to the skin and uniformly distributing them in the stratum corneum upon film administration. The sustained release of HA from the films, following Higuchi kinetics, did not alter the macroscopic characteristics of the film. Although anodic iontophoresis did not noticeably affect the release of HA, it did enhance its penetration into the skin. This enhancement facilitated the permeation of HA with a molecular weight (MW) of up to 2 × 105 through intercellular and transcellular routes. Confocal Raman spectroscopy provided evidence of an approximate 100% increase in the presence of HA with a MW in the range of 1.5-1.8 × 106 in the viable epidermis of human skin after only 15min of iontophoresis applied to the films. Combining iontophoresis with NP-HA films exhibits substantial potential for noninvasive treatments focused on skin rejuvenation and wound healing.

SELECTION OF THE OPTIMAL METHOD OF INTENSIFICATION AND STABILIZATION OF OIL PRODUCTION IN THE FIELDS OF WESTERN KAZAKHSTAN

The article discusses research aimed at determining the effectiveness of measures to intensify oil production in the fields of Western Kazakhstan. Based on the results obtained, recommendations were developed for the further application of oil production intensification methods for the conditions of West Kazakhstan fields. The highest oil displacement coefficient (ODC) in the development of high-viscosity oils can be achieved using thermal production methods. To reduce viscosity, in practice, deep warming of the bottom-hole zone of the well is used, which can be carried out by electrothermal treatment of the bottom-hole zone of the formation, steam treatment of wells using downhole solid fuel heat generators, and so on. A combined heating method is proposed that allows heating the well products. Heating is provided by a solar panel all year round. In case of a decrease in solar activity, it automatically switches to a constant electric current. This method differs from others in that the solar panel continuously supplies electricity, reducing the consumption of electrical energy. In addition, the article presents the results of studies of the optimal heating temperature of the bottom-hole formation zone, potential well flow rates at this temperature and oil viscosity. Recommendations are given on the most rational way of heating the bottom-hole zone of wells in the fields of Western Kazakhstan.

A ubiquitous, nearby reservoir of electromagnetic energy hidden in the fourth spatial dimension as a consequence of Kelvin’s rule (for constant electric currents) and of the Poynting vector

When applying what is called Kelvin’s principle to the elementary currents of two permanent magnets that attract each other, an apparent energy paradox appears. For Kelvin’s principle says that when constant electric currents are displaced with respect to one another, the mechanical work yielded as a result of the action of magnetic forces is equal in amount to the increase (not decrease) in the energy of the total magnetic field. The energy provided by the power supply in order to keep the currents constant is thus twice as large as the mechanical work yielded during the displacement of the current-carrying wires. But when dealing with permanent magnets and their polarization currents, there is still the yield of mechanical work and also the increase in energy of the total magnetic field, but no such thing as a visible power supply. In this article, things are analyzed by using the Poynting vector as an instrument. As a result, the topological assumption of a hidden reservoir of energy sitting in the direction of a fourth spatial dimension turns out to be indispensable in order to save the principle of local conservation of energy and of action by contact. A recognition of this kind was foreshadowed by Mie 100 years ago, who postulated that, in certain, but nevertheless common situations, energy flowed into ambient space out of the particles themselves both in the gravitational and the electromagnetic case.

Influence of current density on constant current electric field enhanced aluminum induced crystallization of amorphous silicon thin films

In this study, electric field-enhanced aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) thin films was investigated considering various current densities. Constant electric currents of 4, 5, and 6 A were applied to assess the Joule heating characteristics during specific durations (40, 15.5, and 9 s). The samples were prepared by depositing a 200-nm thick a-Si layer on a glass substrate and sputtering a 300-nm thick aluminum (Al) layer onto the a-Si layer. During the AIC process, layer exchange occured via the diffusion of silicon (Si) into the Al layer. This phenomenon was verified by the in-situ reflectivity, which was in excellent agreement with thin-film optics calculations. During the annealing, processing temperatures were lower than 470 °C, which is less than the Al-Si eutectic temperature of 577 °C. The Raman peak observed near a wavenumber of 519 cm−1 revealed the formation of polycrystalline silicon films through Joule heating processes. Field-effect scanning electron microscopy images were captured and analyzed to investigate the surface morphology of the samples, specifically focusing on grain growth.

Effects of Age and Sex on the Anorectal Sensory Threshold to Electrical Stimulation: A Single-center Observational Study.

Anorectal sensation is an essential component for maintaining normal defecation and continence. This study aimed to investigate changes in anorectal sensation with age and sex using the anorectal sensory threshold to electrical stimulation in a large population with a broad age spectrum. This study enrolled consecutive adult patients (20-89 years old) who underwent anorectal physiology tests to screen for functional or organic anorectal disease. Anorectal sensitivity was measured using an endoanal electrode with a 45-mm long bipolar needle. A constant electrical current was delivered to the lower end of the rectum and the anal canal. The minimum current in milliamperes at which the initial sensation was felt was defined as the sensory threshold. Overall, 888 patients were included in this study. The most frequent comorbidities were constipation and hemorrhoids. The median sensory threshold for all patients was 0.5 (interquartile range, 0.2-1.5) mA, and the overall sensory threshold was significantly higher in men than in women. The 95% confidence interval of the sensory threshold for men and women were 0.1-6.8 and 0.1-5.1 mA, respectively. The sensory threshold increased significantly with age in both sexes (men, r = 0.384; women, r = 0.410). There was no sex difference in the sensory threshold between ages 20 and 40 years; however, between ages 50 and 70 years, men had a higher sensory threshold than women. The anorectal sensory threshold to electrical stimulation increased with age, and the influence of aging was more significant in men than in women.

Impact of high constant charging current rates on the charge/discharge efficiency in lead acid batteries, for residential photovoltaic system applications

The charging and discharging of lead acid batteries using Traditional Charge Controllers (TCC) take place at constantly changing current rates. These techniques do not permit the accurate estimation of energy input and energy output during charge and discharge processes. In this work, the main objective is to investigate the effect of high constant charging current rates on energy efficiency in lead acid batteries, extending the current range to 8A from 5A already reported in literature. We also present the experimental proof of the variation of electrolyte temperature with magnitude of the constant electric charging current. Firstly, a Constant Current Circuit (CCC), capable of charging the battery at current rates ranging from 0.5A to 8A was built and used to run experiments on two sample lead acid batteries, battery sample 01, the Vanbo battery and battery sample 02, a Winbright battery. Charge and discharge processes were conducted on these batteries through the CCC and efficiencies computed per current rate tested. Secondly, to compare the results of the CCC built with those of a TCC, the very batteries (battery sample 01 and battery sample 02) were charged and discharged through a TCC and their corresponding efficiencies computed. Thirdly, three constant charging current regimes (0.5A, 5A and 8A) were chosen within the tested current rates for which further electrolyte temperature monitoring tests were carried out, using two other lead acid battery samples of different health states. This was carried out on battery sample 03 which was a SIGA lead acid battery type with a compromised state of health and on battery sample 04, another brand new Winbright battery with relatively good state of health. It was noticed that, for the CCC, efficiencies between 62 % and 82 %, were recorded for the Vanbo Battery (Sample 01) while efficiencies of 53 % to 91 % were recorded for the Win Bright Battery (Sample 02). On the other hand, the efficiency of the Vanbo Battery (Sample 01) through the TCC was found to be 66 % while that for the Winbright battery (Sample 02) was found to be 79 %. As for electrolyte temperature monitoring, battery sample 03 with compromised health state registered higher temperatures for higher charging rates while battery sample 04 of good state of health registered no noticeable increase in temperatures even for constant charging current rates up to 8A. Since existing literature had tackled lower current values from 0.5A to 5A, this work therefore comes in with an extension of the current rates, testing higher current magnitudes and obtaining the same results with conclusion that, if the same energy is stored in a lead acid battery at precise rates, the charge/discharge efficiency of the battery increases as the charging current rate increases. As regards electrolyte temperature monitoring, the work provides further proof that even at charging current rates as high as 8A, battery electrolyte temperatures still remain within acceptable limits(below 50 °C).

Investigation of the antimicrobial effect of anodic iontophoresis on Gram-positive and Gram-negative bacteria for skin infections treatment

Iontophoresis, a non-invasive application of a constant low-intensity electric current, is a promising strategy to accelerate wound healing. Although its mechanisms are not yet fully elucidated, part of its action seems related to inhibiting bacteria growth. This work aimed to investigate the antimicrobial effect of iontophoresis using Staphylococcus epidermidis and Escherichia coli strains, Gram-positive and Gram-negative bacteria, respectively. Anodic iontophoresis was applied to each bacterial suspension using Ag/AgCl electrodes, and bacteria viability was evaluated after 24 h incubation by counting colony-forming units. A Quality-by-Design approach was performed to assess the influence of the iontophoresis’ intensity and application time on bacterial viability. Cell morphology was evaluated by scanning electron microscopy. Iontophoresis showed antimicrobial effects on the Gram-positive bacteria only at 5 mA and 60 min application. However, a linear relationship was observed between intensity and application time for the Gram-negative one, causing drastic morphological changes and up to 98 % death. The cell wall of Gram-negative bacteria seems more susceptible to disorganization triggered by iontophoresis-induced ion transport than Gram-positive ones. Therefore, anodic iontophoresis can be a powerful ally in controlling Gram-negative bacteria proliferation in wounds.

Rapid electric field-enhanced crystallization of amorphous silicon thin films with an aluminum layer

A rapid aluminum induced crystallization (AIC) method of amorphous silicon (a-Si) thin film was suggested. A constant electrical current is supplied to an aluminum (Al) layer deposited on the a-Si thin film and anneals the Al/Si stack fast by Joule-heating. The Joule heating is presumed to expedite a-Si thin film crystallization. To investigate the crystallization mechanism, an in-situ temperature and reflectivity measurement was adopted during the process. The maximum crystallization temperature was 744.15 K, which was found to be similar to the typical furnace AIC process temperature and less than the Al/Si eutectic temperature of 850 K. The measured and calculated surface reflectivity demonstrated the rapid Al induced layer exchange behavior between Si and Al layers. The entire process was accomplished for only a few dozens of seconds. This rapid layer exchange is caused by sudden increase of temperature-dependent Al diffusion coefficient in a Si layer and additional electric field enhancement. The Raman peak of 519 cm−1 verified the formation of polycrystalline silicon (p-Si) after the Al etching process. Scanning electron microscopy images showed that the resulting p-Si structure was porous with an average pore size of around 1.2 μm.

Effect of thickness and chemical composition on thermal resistance of steel dilatometric specimens under heating‐cooling cycles by Joule heating

AbstractThe effect of thickness and chemical composition on the electrical power and thermal resistance of dilatometric specimens heated by Joule heating are analyzed in different steels, using stepped tests of constant temperature and electrical current. In the stepped constant temperature tests, the electric current necessary to maintain the target temperature in a specific time is measured, while in the electric current tests the electrical current is maintained until the maximum temperature stabilizes. The results show that the electrical power behaves linearly with the thickness associated with the transfer area, while the thermal resistance behaves potentially; both values depend on the chemical composition due to electrical resistivity. The steels with a higher concentration of alloying elements have a better response to Joule heating. However, thickness is the parameter that most influences electrical power due to changes in transfer area and electrical current density, as well as in the mass of the specimen to be heated. Finally, based on the results obtained, predictions are realized for the design of thicker specimens, maintaining the observed behavior; i. e., as the thickness of the specimen increases, the increase in electrical power and thermal resistance is maintained.

MORPHOLOGICAL CHARACTERISTICS OF REPARATIVE OSTEOGENESIS IN THE RATS LOWER JAW UNDER THE CONDITIONS OF USING ELECTRICAL STIMULATION.

Aim: The purpose of the study was to identify the morphological features of reparative osteogenesis in the rats lower jaw under the conditions of using electrical stimulation. Materials and Methods: An experiment was conducted on 24 mature male rats of the WAG population. Two groups were formed. Group 1 included 12 rats that were modeled with a perforated defect of the lower jaw body. Group 2 included 12 animals that were modeled with a perforated defect similar to group 1. In animals, a microdevice for electrical action was implanted subcutaneously in the neck area on the side of the simulated bone defect (a temporary Videx AG 4 battery; a constant sinusoidal electric current of an unchanging nature 1 milliampere, frequency 30 W). The negative electrode connected to the negative pole of the battery was in contact with the bone defect. The battery and electrode were insulated with plastic heat shrink material. Morphological and statistical methods were used. Results: The positive effect of electrical stimulation on reparative osteogenesis was due to a decrease in the severity of hemodynamic disorders, activation of angiogenesis in granulation tissue, which was one of the components of the regenerate that filled the bone defect, matured and turned into connective tissue; stimulation of the proliferative potential of fibroblastic cells and cells with osteoblastic activity in granulation tissue; increasing the proliferative potential of osteoblastic elements of bone tissue bordering the cavity; stimulation of macrophage cells and processes of cleansing the bone cavity from fragments of a blood clot and alteratively changed tissues; formation of clusters of adipocytes in the loci of connective and granulation tissue of the regenerate; the process of metaplasia of connective tissue into bone tissue; an increase of the foci of hematopoiesis in the intertrabecular spaces of lamellar bone tissue. Conclusions: A comprehensive clinical and experimental study conducted by the authors proved that electrical stimulation activates the reparative osteogenesis in the lower jaw, which occurs through direct osteogenesis and does not finish on the 28th day of the experiment.

Degradation mechanism of blended cement pastes in sulfate-bearing environments under applied electric fields: Sulfate attack vs. decalcification

Applied electric fields, the reason behind stray currents, accelerate the ingress of sulfate into cementitious materials. To identify mitigation approaches, this study investigates the effects of slag and fly ash on sodium sulfate attacks of cement pastes under a constant electric current. The mineralogical alterations induced by the attacks were analyzed using X-ray diffractometry, thermogravimetric analysis, scanning electron microscopy, and thermodynamic modeling. The dissolution of aluminates in the slag and fly ash induced a monosulfate-rich area (>∼20 mm from the cathode surface) to form next to the ettringite-rich area on the sample surface (<∼20 mm). This effect reduced the availability of SO42− in the pore solution, thereby hindering the penetration of sulfate. Meanwhile, the consumption of portlandite by the pozzolanic reaction lowered the decalcification resistance of the materials. This produced a wide area that endured the decomposition of portlandite and carbonate-AFm. Overall, blending 30% fly ash did not improve the resistance of the material to either sulfate attacks or decalcification; blending 50% slag can effectively mitigate sulfate ingress, though decalcification may become a governing mechanism in the degradation process.

Fluctuational electrodynamics in and out of equilibrium

Dispersion forces between neutral material bodies are due to fluctuations of the polarization of the bodies. For bodies in equilibrium these forces are often referred to as Casimir–Lifshitz forces. For bodies in relative motion, in addition to the Casimir–Lifshitz force, a lateral frictional force (“quantum friction”, in the zero temperature limit) comes into play. The widely accepted theory of the fluctuation-induced forces is based on the “fluctuational electrodynamics”, when the Maxwell equations are supplemented by random current sources responsible for the fluctuations of the medium polarization. The first part of our paper touches on some conceptual issues of the theory, such as the dissipation-less limit and the link between Rytov’s approach and quantum electrodynamics. We point out the problems with the dissipation-less plasma model (with its unphysical double pole at zero frequency) which still appears in the literature. The second part of the paper is devoted to “quantum friction”, in a broad sense, and it contains some novel material. In particular, it is pointed out that in weakly dissipative systems the friction force may not be a stationary process. It is shown, using an “exact” (nonperturbative) quantum treatment, that under appropriate conditions, an instability can occur when the kinetic energy (due to the relative motion between the bodies) is transformed into coherent radiation, exponentially growing in intensity (the instability gets eventually limited by nonlinear effects). We also discuss a setup when the two bodies are at rest but a constant electric current is flowing in one of the bodies. One may say that only the electron component of one body is dragged with respect to the other body, unlike the usual setup when the two bodies are in relative motion. Clearly, there are differences in the frictional forces between the two setups.

Experimental Analysis on the Impact of Current on the Strength and Lifespan of a Ni-Ti Element

Intelligent materials, especially materials with shape memory, are an important discovery, with technical applications in the medical and aerospace field, among others, which led to the development of systems and applications with multiple advantages and disadvantages due to ignorance about their functionality. This paper presents an application developed in the research laboratory for determining and monitoring the behavior of a material element with Ni-Ti shape memory, and its lifespan. The application allows the stress level of the Ni-Ti element subjected to numerous repeated cycles of deformation to be determined by supplying it to a constant electric current. Thus, the results show the variation of the Ni-Ti element force, in the form of a spring, at the ambient temperature variations as well as force variations at different numbers of attempts. The Ni-Ti alloy has both shape retention and superelasticity properties, being the most common in the fields of applicability. Due to its unique properties, it can be used in the most demanding applications in the medical field, usually involving difficult conditions of resistance to fatigue.

Transient behaviour of electrovortex flow in a cylindrical container

This study is a continuation of the combined experimental and numerical investigation [1] of the flow of the eutectic GaInSn alloy inside a cylindrical vessel exposed to a constant electrical current. The emerging electrovortex flow driven by the interaction of the current, which is applied through a tapered electrode, with its own magnetic field might have both detrimental and advantageous effects in liquid metal batteries. While the former work [1] was mainly concerned with time-averaged results, this paper focuses on the transient behaviour of the electrovortex flow which becomes most relevant under the influence of an external axial field. The additional Lorentz force generated by the interaction of the imposed current with the vertical component of the geomagnetic field bz drives the ordinary electrovortex jet flow into a swirling motion. Velocity distributions and motion characteristics, such as spiral streamlines and shortened and irregularly swinging jet regions, are investigated. The mechanism is analysed in detail for bz = 25.5 {\mu}T. The maximum angular velocity of the rotating jet is basically linearly dependent on bz, at least for the values studied here. A good agreement between the transient simulation and the experimental result is shown.

Competition of localized thermal buoyancy and Lorentz forces in an electrolyte enclosed in a cavity

We study the flow of an electrolyte inside a slender square cavity produced by two competing localized forces, the thermal buoyancy force produced by the heating of a central part of the horizontal bottom wall and a vertical downward Lorentz force. This force is produced by a constant horizontal electric current between the slender vertical walls and a couple of circular magnets with opposing polarization placed on the center of both square vertical walls. The flow inside the cavity is considered two dimensional and simulated using the lattice Boltzmann equation method. We find the map of the flow patterns and their transitions for a Grashof number Gr in the range 0≤Gr≤4×103 and a Chandrasekhar number Ch in 0≤Ch≤1×107. For Gr≤2×103, the plane Gr-Ch can be divided in three regions with sharp changes in the flow patterns and the average Nusselt number on the top wall and the average asymmetry. One region is dominated by the buoyancy force, another by the Lorentz force, and there is an intermediate one, where neither of these forces dominates. For larger Gr, there are no sharp transitions.

Monocathode installation for electrochemical cleaning of oil-contaminated soils

One of the promising solutions for soil remediation is the impact on oil-contaminated areas with a constant electric current of small magnitude. The features of this method in comparison with others that require soil excavation or treatment with sorbents are ease of implementation, energy efficiency and economic feasibility. The cleaning process is carried out directly on the contaminated site. Electrochemical cleaning occurs when the electrodes are submerged into the soil to a depth of contamination and electric voltage applied to them. In this case, the pollutants transfer processes of under the influence of electric current and redox reactions are initiated. However, the traditional realization of the electrochemical method of cleaning soils contaminated with oil and oil products is accompanied by a high material consumption due to the large number of electrodes used, various energy losses depending on the materials of the cathode and anode and their relative position in the contaminated area, as well as insufficient environmental efficiency due to the accumulation of contaminated liquid in the cathode area. In view of the indicated disadvantages, the practical application of the method requires scientifically grounded engineering, the purpose of which is to design new energy- efficient, environmentally friendly, mobile installations.