Reverse Phenomenon Research Articles

Challenging anticoagulation decisions in atrial fibrillation: a narrative review.

Atrial fibrillation (AF) is common and warrants consideration of oral anticoagulant (OAC) medication. Usually, the decision is straightforward, following the pathway outlined in the European Society of Cardiology's guideline; however, certain situations fall outside of this evidence base - such as a diagnosis of subclinical AF made via implanted devices or wearable electrocardiogram monitors, or alternatively diagnosis of 'secondary AF' following a major stressor. Subclinical AF is associated with stroke, though not to the extent of clinical AF, and the benefits of anticoagulation appear to be lower. Longer episodes are more clinically meaningful, and recent randomised controlled trials have demonstrated that some patients derive benefit from OAC. Similarly, when AF is triggered by sepsis or non-cardiac surgery, specific evidence supporting OAC initiation is lacking and clinician behaviour is variable. Observational data demonstrate poorer outcomes in these patients, implying that the perception of a transient, reversible phenomenon may not be correct. Contrastingly, cardiac surgery very frequently induces AF, and the benefits of anticoagulation rarely outweigh the risks of bleeding. Following ischaemic stroke, recent evidence suggests that early (re-)initiation of OAC should be considered as this does not increase the risk of haemorrhagic transformation as previously hypothesised. This narrative review summarises the available literature and outlines, where possible, practical advice for clinicians facing these common clinical dilemmas.

КОМПЛЕКСНЫЙ ПОДХОД К ПРЕДУПРЕЖДЕНИЮ ДЕПРИВАЦИИ ПОДРОСТКОВ

This article analyzes an integrated approach to the prevention of adolescent deprivation, including evochomological, behavioral, and prosocial components. The importance of objective and subjective factors in the deprivation development of personality is shown. The definition of adolescent “deprivation” is interpreted by the authors as a lack of attention, attitudes necessary for the full development of personality. The inability of an individual to build a constructive dialogue with the institutions of social space initiates the development of a sense of detachment, dislike, abandonment, uselessness to others, including family institutions and schools. As a result of deprivation, a teenager loses the ability to empathy, tolerance, cannot listen and hear another, initiates destructive conflicts, cynicism, snobbery, aggressiveness, indifference, abuse, lack of self-criticism. The author of the article argues the importance of the symbiosis of teachers, psychologists, doctors, lawyers, juvenile psychologists, mediators, evohomologists, preventologists in preventing and minimizing adolescent deprivation. It is necessary to treat not the disease, but the patient, therefore, before making a plan for the prevention and leveling of adolescent deprivation, it is necessary to identify the psychological and pedagogical causes of its occurrence, the specifics of the course and consequences for the development of the personality of minors. Institutions of education and socialization should remember that deprivation as a psychological and pedagogical phenomenon is a reversible phenomenon. The main trends in the prevention of deprivation, taking into account individual factors, should be aimed at creating a favorable psychological climate in the family, supporting constructive communication between adults and children, self-actualization of adolescents, the development of their social maturity, social immunity, and responsible behavioral strategy.

A review of the electrochemical and galvanic corrosion behavior of important intermetallic compounds in the context of aluminum alloys.

Aluminum alloys are widely sought for different applications due to their high strength-to-weight ratio. Most often this increased strength of the alloy is achieved by specific alloying elements and heat treatment processes which give rise to second phases intermetallic particles (IMPs) also known as intermetallic compounds (IMCs). These second phases play a dominant role in the corrosion susceptibility of aluminum alloys. This review provides a systematic survey of the electrochemical, and galvanic corrosion behavior of IMPs in the context of aluminum alloys. A discussion of the electrochemical/galvanic corrosion behavior of selected/important intermetallic compounds that are commonly found in aluminum alloys such as the Q-phase (Al4Cu2Mg7Si8), π-phase (Al8Mg3FeSi6), θ-phase (Al2Cu), S-phase (Al2CuMg), the β-phase (Mg2Si), β-phase (Al3Mg2), δ (Al3Li), η-phase (MgZn2), and β-phase (Al3Fe) is provided. In addition, the limitations in the electrochemical characterization of intermetallic compounds, the research gap, and prospects are also provided in addition to the phenomenon of galvanic polarity reversal and self-dissolution of IMPs.

Establishment of analytical model for electrostatic discharge gate-to-source capacitance of power metal-oxide-semiconductor field-effect transistor

In the actual human body model (HBM) test, it is found that the electrostatic discharge (ESD) test results of various power metal-oxide-semiconductor field-effect transistor (MOSFET) devices show asymmetry between forward withstand voltage and reverse withstand voltage, while the ESD process does not distinguish between positive direction and negative direction. Large differences between forward and reverse withstand voltages are unacceptable for power MOSFETs or as ESD protection devices. The problem of its causing device failure is particularly pronounced. In this work, by establishing the analytical model of gate-to-source capacitance of SGT-MOSFET, VUMOSFET and VDMOS under the forward and reverse voltages, we comparatively analyze the reasons for the asymmetry of the forward and reverse withstand voltages and their different ratios of the three kinds of power MOSFETs, which provides a theoretical basis for testing the device’s ESD and the analyzing their reliability. It is found that the ESD forward and reverse withstand voltage asymmetry phenomena of different power MOSFET structures are related to the variation of gate-to-source capacitance, caused by the reverse-type layer. When a forward voltage is applied across the gate and source, the device gate-to-source capacitance consists of the oxide layer capacitance around the gate in parallel; when a reverse voltage is applied, the gate-to-source capacitance consists of the virtual gate-to-drain capacitance in series with the inverse layer capacitance and then in parallel with the other oxide layer capacitance around the gate. This results in a decrease of the gate-to-source capacitance at the reverse voltage, making the device reverse withstand voltage greater than the forward withstand voltage. The difference in the ratio of ESD reverse withstand voltage to forward withstand voltage among different devices is related to the change of the capacitance of the inverse layer in the gate-to-source capacitor under reverse voltage caused by the difference in device structure.

Hydrostatic pressure-induced reversible phase transformation in iron oxide nanoparticles.

We report hydrostatic pressure-induced reversible phase transformation in maghemite γ-Fe2O3 nanoparticles (cubic → tetragonal → cubic) using an in situ diamond anvil cell (DAC) technique. Thermal arc plasma-synthesized nanoparticles, particularly in a He gas medium, exhibit the reversible phase transformation under pressure ranging from 0 to 2.58 GPa. Rietveld refinement reflects that cubic to tetragonal maghemite phase transformation coexists with a cubic metallic Fe phase at 0.55 GPa pressure. The generation of two new superlattice reflections at 6.93° and 8.11°, respectively, reflects the phase transformation. The presence of a core-shell-type nanostructure observed from transmission electron microscopy micrographs is found to exhibit a spin glass shell-type behavior. This triggers pressure-induced fluctuating magnetization and interparticle interaction-induced surface anisotropy and spin disorder with broken bonds, translational symmetry, and incomplete coordination. This leads to overcoming the nucleation barrier at the surface, subsequently denser nucleation sites and increased nucleation probability. This further leads to an atomic rearrangement and tetragonality in the maghemite phase. Furthermore, with increasing pressure, the reversible structural change, i.e. from the tetragonal to cubic maghemite phase, has been explained in the light of the "internal stress model". The grains are again forced back to the cubic phase via generation of uniform compression along the c-axis and tension along the a and b axes. The spin glass behavior of the core-shell nanostructure along with the "internal stress model" explain the whole reversible phase transformation phenomenon in the γ-Fe2O3 phase.

Exploring cross-modal plasticity in the auditory-visual cortex post cochlear implantation: implications for auditory and speech function recovery and mechanisms.

The aim of this is to explore changes in cross-modal reorganization within the auditory-visual cortex after cochlear implantation, examining their influence on auditory and speech functions along with their underlying mechanisms. Twenty prelingually deaf children who received cochlear implantation and rehabilitation training at our hospital between February 2022 and February 2023 comprised the prelingual deaf group. Simultaneously, 20 healthy children served as the control group. The prelingual deaf group underwent brain cortical activity assessment and evaluation of auditory-speech recovery pre-surgery, at postoperative weeks 1 and 2, and at months 1, 3, 6, 9, and 12. The control group underwent parallel assessments and evaluations. We analyzed the correlation between cortical activity in the auditory-visual cortex of patients and their auditory-speech functional recovery. The group with prelingual deafness displayed elevated levels of auditory and visual cortical electromagnetic intensity compared to the control group, both prior to and 9 months after surgery. However, by the 12-month mark post-surgery, there was no discernible distinction between the two groups. Following surgery, the prelingually deaf group exhibited a progressive improvement in both Categories of Auditory Performance (CAP) and Speech Intelligibility Rate (SIR), initially lagging behind the control group. Notably, a negative correlation emerged between auditory and visual cortical electromagnetic intensity values and CAP/SIR scores at the 12-month post-surgery assessment. Cochlear implantation in prelingually deaf children results in elevated activity within the auditory and visual cortices, demonstrated by heightened electromagnetic intensity readings. Cross-modal reorganization is observed temporarily at 3 months post-surgery, which resolves to baseline levels by 12 months post-surgery. This phenomenon of reversal correlates with the restoration of auditory and speech functions in these children.

Significant role of thermal effects in current-induced exchange bias field switching at antiferromagnet/ferromagnet interface

The current-induced switching of in-plane exchange bias field (<i>H</i><sub>eb</sub>) has many advantages, such as switching without assistance of external magnetic field, excellent immunity to magnetic field, and robust magnetic anisotropy. However, the blocking temperature of the nanoscale antiferromagnet/ferromagnet (AFM/FM) heterostructure is relatively low and susceptible to thermal effects. Therefore, the Joule heating theoretically plays a substantial role in the switching of <i>H</i><sub>eb</sub> driven by current, but its underlying mechanism requires further investigation and verification. We prepare a series of Pt/IrMn/Py heterostructures with varying antiferromagnet IrMn thicknesses and systematically investigate the role of thermal effects in current-driven <i>H</i><sub>eb</sub> switching. These results demonstrate that under millisecond-level current pulses, Joule heating heats the device above the blocking temperature, leading to the decoupling of exchange coupling at AFM/FM interface. Simultaneously, the Oersted field and spin-orbit torque field generated by the current switch the ferromagnetic moments, and then a new <i>H</i><sub>eb</sub> will be induced along the direction of the ferromagnetic moments in the cooling process. Furthermore,in the switching process of <i>H</i><sub>eb</sub>, the anisotropic magnetoresistance curve of the AFM/FM heterostructure exhibits a temperature-dependent two-step magnetization reversal phenomenon. Theoretical analysis indicates that this phenomenon arises from the competitive relationship between exchange bias coupling at AFM/FM interface and direct exchange coupling between the ferromagnetic moments. The findings of this study elucidate the crucial role of thermal effects in the current-driven switching of <i>H</i><sub>eb</sub>, thereby contributing to the advancement of spintronic devices based on electrically controlled <i>H</i><sub>eb</sub>.

Intrinsic Sinus Node/Atrioventricular Node Dysfunction Requiring Pacemaker Implantation: Role of Former Professional Sport Activity.

Sinus bradycardia and first degree or second degree Mobitz type I atrioventricular (AV) block in an athlete are considered adaptive and reversible phenomena; however, some evidence suggests that they may persist after detraining and become pathological. The aim of the study was to investigate the characteristics of a group of former professional athletes who required pacemaker (PM) implantation for intrinsic (idiopathic) sinus node (SN) dysfunction or AV block in comparison to control groups of sedentary individuals. We included all patients who underwent PM implantation during 2022. Three groups were compared: group 1 including 18 former professional athletes who received a PM for SN dysfunction/AV block in the absence of heart disease; group 2 including the first 20 sedentary individuals without heart disease who underwent PM implantation; and group 3 including all other 323 patients who received PM, the majority with underlying heart diseases. Compared to the non-athlete control group 2, the mean age at diagnosis and at the time of PM implantation of former professional athletes did not show statistically significant differences. However, subgroup analysis revealed significant differences depending on the type of sports discipline: the age at diagnosis and at PM implantation was significantly lower in former endurance athletes than former strength/mixed athletes, control non-athletes, and all other patients. Moreover, former endurance professional athletes exhibited a higher prevalence of second or third degree AV block (78%) as the reason for PM implantation compared to power/mixed athletes (44%). The other clinical characteristics, including echocardiographic parameters, did not differ between former athletes and non-athletes. Former professional endurance athletes with idiopathic SN dysfunction/AV block manifested the disease earlier in the life course compared to former power/mixed athletes and non-athletes. This suggests that bradycardia/AV block caused by intense and prolonged endurance sports may not always be benign and adaptive phenomena.

Reversible evolution phenomenon of particle during crystal growth: A phase-field study

The two-dimensional thermodynamically consistent phase field model, which consists of the anisotropic Allen-Cahn type equation and the heat equation, is used to study the morphological pattern of the particle in the initial stage of crystal growth. The results reveal the locally reversible growth of the particle in the initial stage of crystal growth. Specifically, some parts of the particle interface first grow inward, while others grow outward from the interface of critical nucleation, until the growth speed of the interface becomes zero. After this, the inward growth parts start to grow outward with other parts. The locally reversible growth of the particle leads to the development of a petal-like shape. The particle radius size dependence of the temperatures along the parts of the particle interface in different crystallographic directions at different time points is studied. By a series of results, the correlations between the morphological pattern selection of the particle and the model parameters, including undercooling and anisotropic strength, are analyzed. These results contribute to understanding the fundamental mechanism of the particle evolution during crystal growth.

The Power of Reference Electrodes in AEM Electrolysis

The use of reference electrodes is a powerful diagnostic tool to determine the overpotentials associated with oxygen and hydrogen evolution reaction. Yet, the use of reference electrodes in flow cells is still uncommon and provides several challenges especially related to the stability of the potential of the reference electrode. This study investigates the use of a reference electrode in a well-performing iridium-free AEM flow cell with a cell potential of <1.8 V @ 1.5 A cm-2. The reference electrode consists of electrically insulating foil with two platinum wire electrodes on one side as shown in Figure 1(left). A small micro-current is passed through the platinum wires to maintain hydrogen coverage on the reference electrode to establish equilibrium cell potential. The use of the reference electrode shows that the platinum-ruthenium cathode performs particularly well with an overpotential of <0.1 V @ 0.2 A cm-2.The reference electrode also is useful for the study of cell degradation. One of the major challenges of coupling electrolyzer directly to renewables are reverse currents flowing after shutdown in alkaline and AEM electrolyzers [1]. In this study, polarities were reversed to simulate these reverse currents. This lead to a significant increase in cell potential. It is clearly evident from Figure 1(right) that the cathode overpotentials increased significantly after this reverse current application, thereby indicating that the platinum-ruthenium cathode is vulnerable to reverse currents.[1]Ashraf Haleem et al, Effects of operation and shutdown parameters and electrode materials on the reverse current phenomenon in alkaline water analyzers, Journal of Power Sources, Volume 535, 2022, 231454, ISSN 0378-7753, https://doi.org/10.1016/j.jpowsour.2022.231454 Figure 1

99mTc-MIBI washout rate as a marker of myocardial mitochondrial dysfunction: A systematic review and meta-analysis

BACKGROUND: This review outlines the features of the pharmacokinetics of the perfusion radiopharmaceutical 99mTc-MIBI, which allows the assessment of myocardial mitochondrial dysfunction, and shows the main clinical applications of the phenomenon of increased 99mTc-MIBI washout rate. AIM: To systematize the data of fundamental (experimental) and clinical studies evaluating and estimating mitochondrial dysfunction according to myocardial perfusion scintigraphy data and perform meta-analysis of clinical studies in this field. MATERIALS AND METHODS: PubMed, Scopus, Google Scholar, and eLibrary databases were searched until mid-2023. The following keywords, their combinations, and Russian-language counterparts were used: mitochondrial dysfunction, 99mTc-MIBI, 99mTc-Tetrofosmin, myocardial perfusion scintigraphy, reverse redistribution, washout, and washout rate. In the meta-analysis, a random-effects model was used to calculate the mean difference estimate. RESULTS: Forty articles were selected for systematic analysis: 13 were experimental, 24 were original clinical papers, 2 were clinical cases, and 1 was a review. Six studies using a case–control design were selected for the meta-analyses. The total number of patients in the systematic review and meta-analysis were 551 and 196, respectively. In the analysis of the literature, the severity of the reverse redistribution phenomenon and 99mTc-MIBI washout rate correlated with mitochondrial and myocardial microstructure, left ventricular contractility and hemodynamics, natriuretic peptide levels, exercise tolerance, coronary atherosclerosis severity, myocardial oxidative metabolism, and risk of cardiovascular events. The meta-analysis showed that the washout rate was statistically significantly accelerated in individuals with cardiac pathologies, relative to controls (mean difference score, 9.5771 [95%]; confidence interval, 6.6001–12.5540; z=6.3053, p 0.0001). CONCLUSION: The assessment of mitochondrial function by 99mTc-MIBI washout evaluation may provide additional insights into the functional status of cardiac muscles.

Onsager-Casimir reciprocal relations as a consequence of the equivalence between irreversibility and dissipation

Abstract The equivalence between irreversibility and dissipation entails that the Onsager reciprocal relations hold unconditionally, requiring the part of the phenomenological matrix describing dissipative phenomena to be symmetric. The antisymmetric part of the phenomenological matrix corresponds to the Casimir’s variant of the reciprocal relations and describes reversible phenomena. Further, we discuss the relationship of the reversibility and entropy production, including the role of the level of description, and we use the chemotaxis as an illustrative example.

Analysis of third alternatives' impact on PROMETHEE II ranking

AbstractSo far, the rank reversal (RR) phenomenon has been heavily discussed in the multiple criteria analysis literature. In this work, instead of focusing on RR occurrences within PROMETHEE II, an analysis of the third alternative with respect to a given pair of alternatives is conducted. The aim is to provide a way to identify third alternatives able to cause RR between a specific pair. This opens the question of building alternatives causing RR occurrences. Such alternatives can then be used to assess the resistance a given ranking has to RR. In the end, two different approaches are used. The first considers the number of third alternatives to be added to generate RR for a given pair of alternatives. While, the second one, provides a new threshold for RR occurrences in PROMETHEE II.

Performance of rough secant slider bearing lubricated with couple stress fluid in the presence of magnetic field

The effect of surface roughness, magnetic field, and couple stress on the performance of secant slider bearing is studied in this paper. The effectiveness of the bearing is assessed by using a couple stress liquid as the lubricant in the process. Because of microstructural impacts, couple stress fluids have distinctive rheological characteristics. These features have the potential to make a major impact on the bearing’s performance. The novel aspect of this study is that the roughness of the secant slider is taken into consideration. The modified Reynolds equation is derived using Christensen’s stochastic theory for roughness. Here, both transverse and longitudinal roughness patterns are considered. The analytical solutions are obtained for steady-state pressure, load-carrying capacity, film stiffness, and damping coefficient. The results are presented for various parameters through graphs and tables. The combined effect of the magnetic field and couple stress is significant on bearing characteristics. It is noticed that the bearing features increase with the longitudinal roughness parameter, and the reverse phenomenon is observed with the transverse roughness parameter. When a transverse roughness pattern is assumed on a secant slider bearing, characteristics like pressure, load, stiffness of the film, and damping coefficient increase significantly.

The Investigation of critical thinking disposition among Chinese primary and middle school students

PurposeCritical thinking has become the essential competency for students in the 21st century. the purpose of this study is to understand the present situation critical thinking disposition among Chinese primary and middle school students. Methodthe study surveys of 18,737 students from the fourth grade of primary school to the twelfth grade of senior high school in 13 provinces in China using a self-designed questionnaire, and interviews 25 primary and middle school students in depth. ResultThe results show that: (a) The average critical thinking disposition score of Chinese primary and middle school students is 7.33 point, indicating room for improvement. (b) The development of the subordinate dimensions of critical thinking disposition of Chinese primary and middle school students is unbalanced, students perform better in open-mindedness and curiosity, but struggle with truth-seeking spirit and independent thinking. (c) In terms of the change of academic stage, the critical thinking disposition of students is generally improving, but the relationship between critical thinking and grade level is not linear, and there is a reverse phenomenon in the dimensions of curiosity and independent thinking. (d) middle school students do not meet the standards and requirements of critical thinking spirit set by the curriculum standards, and they are generally dissatisfied with their critical thinking disposition; (e) Students from cities perform better than those from rural areas in self-examination, open-mindedness, inquisitiveness and evidence-based reasoning.

Thermally Reversible Luminescence in Ferroelastic Phase Transition Materials

AbstractThe thermally reversible luminescent materials with information encryption are important and widely used in the information age. However, it is challenging to obtain such materials. In this work, a 0D In‐based hybrid compound [(CH3)3NCH2CHCH2]2InCl5 ((TAMAC)2InCl5) is synthesized and undergoes a high‐temperature ferroelastic phase transition with an Aizu notation of mmF2/m at 333 K. In the room temperature phase (RTP), it shows a weak blue glow with a photoluminescent quantum yield (PLQY) of 0.32% under the UV lamp at 365 nm. By using a metal ion doping strategy to improve the photophysical properties, a series of compounds is obtained: (TAMAC)2In1‐xCl5:xSb3+ (x = 0.1%,0.5%,1%, and 1.5%, x represents the actual amount) with the same ferroelastic phase transition as that found in (TAMAC)2InCl5. When x = 0.5%, the PLQY reaches 50.66% with the luminous color change from blue to orange. Interestingly, it is found that the orange luminescence of the doped materials can rapidly and reversibly quench and recover between heating and cooling cycles, where the thermally induced phase transition results in this thermally reversible luminescence phenomenon. This discovery reveals the mechanism of luminescence quenching and phase transition, and provides a new pathway for the construction of new thermal‐sensitive luminescent materials with information encryption.

Photochromic Nucleosides and Oligonucleotides.

Photochromism is a reversible phenomenon wherein a material undergoes a change in color upon exposure to light. In organic photochromes, this effect often results from light-induced isomerization reactions, leading to alterations in either the spatial orientation or electronic properties of the photochrome. The incorporation of photochromic moieties into biomolecules, such as proteins or nucleic acids, has become a prevalent approach to render these biomolecules responsive to light stimuli. Utilizing light as a trigger for the manipulation of biomolecular structure and function offers numerous advantages compared to other stimuli, such as chemical or electrical treatments, due to its non-invasive nature. Consequently, light proves particularly advantageous in cellular and tissue applications. In this review, we emphasize recent advancements in the field of photochromic nucleosides and oligonucleotides. We provide an overview of the design principles of different classes of photochromes, synthetic strategies, critical analytical challenges, as well as structure-property relationships. The applications of photochromic nucleic acid derivatives encompass diverse domains, ranging from the precise photoregulation of gene expression to the controlled modulation of the three-dimensional structures of oligonucleotides and the development of DNA-based fluorescence modulators. Moreover, we present a future perspective on potential modifications and applications.

Estimating the yield stress of soft materials via laser-induced breakdown spectroscopy

Taking three typical soft samples prepared respectively by loose packings of 77-, 95-, and 109-μm copper grains as examples, we perform an experiment to investigate the energy-dependent laser-induced breakdown spectroscopy (LIBS) of soft materials. We discovered a reversal phenomenon in the trend of energy dependence of plasma emission intensity: increasing initially and then decreasing separated by a well-defined critical energy. The trend reversal is attributed to the laser-induced recoil pressure at the critical energy just matching the sample’s yield strength. As a result, a one-to-one correspondence can be well established between the samples’ yield stress and the critical energy that is easily obtainable from LIBS measurements. This allows us to propose an innovative method for estimating the yield stress of soft materials via LIBS with attractive advantages including in-situ remote detection, real-time data collection, and minimal destructive to sample.

Polarization- and Gate-Tunable Optoelectronic Reverse in 2D Semimetal/Semiconductor Photovoltaic Heterostructure.

Polarimetric photodetector can acquire higher resolution and more surface information of imaging targets in complex environments due to the identification of light polarization. To date, the existing technologies yet sustain the poor polarization sensitivity (<10), far from market application requirement. Here, the photovoltaic detectors with polarization- and gate-tunable optoelectronic reverse phenomenon are developed based on semimetal 1T'-MoTe2 and ambipolar WSe2 . The device exhibits gate-tunable reverse in rectifying and photovoltaic characters due to the directional inversion of energy band, yielding a wide range of current rectification ratio from 10-2 to 103 and a clear object imaging with 100 × 100 pixels. Acting as a polarimetric photodetector, the polarization ratio (PR) value can reach a steady state value of ≈30, which is compelling among the state-of-the-art 2D-based polarized detectors. The sign reversal of polarization-sensitive photocurrent by varying the light polarization angles is also observed, that can enable the PR value with a potential to cover possible numbers (1→+∞/-∞→-1). This work develops a photovoltaic detector with polarization- and gate-tunable optoelectronic reverse phenomenon, making a significant progress in polarimetric imaging and multifunction integration applications.

MHD Free Convection Heat Transfer in Nano-Fluid Flow in Square Porous Cavity of TiO2 Nanoparticles with Base Fluid Engine Oil

In this article, the MHD-free convection heat transfer behaviour of oil-based nanofluids is explored numerically inside a square cavity enclosure filled with a porous material. The governing equations are derived using Brinkman and Buongiorno’s two-phase nanofluid models. We developed the mathematical model for the over-research problem for heat transfer enhancement applications; the finite volume approach was used to solve dimensionless governing equations. The SIMPLE algorithm is used to calculate the values of pressure and velocity. The investigation of nanofluid with engine oil in the presence of magnetic field in square cavity for the thermal application is not studies. The following parameters are investigated to find out the heat transfer analysis: Ra = 0, porosity = 10, initial volume concentrations = 0–0.05, constant angle of magnetic field = 0, Hartmann Number Ha = 0,100, Prandtl Number Pr = 0.8. The results are also compared with existing literature. It is also indicated that the effect of Nusselt number is very interesting at different values of Ra, i.e., heat transfer rate increases when volume fraction increases at the contact hot wall of the cavity, but reverse phenomena are observed at the cold wall.