Double Step Research Articles

Thermal explosion and distribution of hydromagnetic Eyring–Prandtl double exothermic diffusion-reaction fluid in a porous channel

Harmful waste discharge poses a global threat to environmental degradation, as incomplete combustion of hydrocarbons can lead to unusual diseases and natural disasters, as well as toxic discharge. Therefore, this research aims to investigate the thermal explosion and distribution of hydromagnetic Eyring–Prandtl fluid during double exothermic combustion in a porous channel. The working Eyring–Prandtl fluid is assumed to be fully viscoelastic to inspire the combustion process in the absence of material deformation. A partial differential model of an electromagnetic pressure-driven flow is developed to govern the combustion reaction process in the presence of chemical kinetics, non-isothermal fixed wall constraints, and without fluid material reactant consumption. The model is transformed into an invariant form by introducing similarity variables; the resultant dynamical equations are solved via a finite difference semi-implicit scheme. The graphs and tables demonstrate that the rising parameter values for the double reaction step propelled heat transfer to help improve combustion processes. Also, the material dilatant parameter enhanced the fluid viscosity for increased chemical industrial usage which implies that, excessive heat generation due to exothermic combustion must be supervised to circumvent reactant species blowup. In addition, the magnetic field created complex dynamics in the fluid by introducing electromagnetic Lorentz forces, which changed the reaction rate and heat distribution inside the channel. Furthermore, there is a strong positive correlation between the results obtained in the current study and the existing published data.

MEMS fast steering mirror with a large optical aperture and high surface quality for free-space optical communication

This work presents a MEMS fast steering mirror fabricated by an 8-inch AlScN platform, with a large optical aperture of up to 10 mm and high surface quality (RMS < 20 nm, PV < 120 nm), intended for free-space optical communication. The device comprises a high reflective mirror plate, a pillar and four cantilever beams with AlScN thin films. This device is prepared by a wafer-level eutectic bonding process. A reinforcement structure is proposed to increase the resonant frequency and the resistance to deformation. The mechanical performance, including resonant frequency, step response, linearity, and long-term stability are characterized. The maximum tilting angle is 1.38 mrad at 68 V, the settling time is improved from 400 ms in the open-loop control mode to 0.5 ms with the double step algorithm. The relationship of the resonant frequency, surface figure, and the depth of reinforced ribs is studied through characterizing devices with different depths of reinforced ribs. The bonding quality and the mutual melting states of bonding layers interface are investigated.

Analysis of Spatiotemporal Gait Variables before and after Unilateral Total Knee Arthroplasty

This study aimed (a) to evaluate the spatiotemporal gait variables of total knee arthroplasty (TKA) before (pre-) and after the procedure (post-), and (b) to investigate the influence of the surgical side on these variables. Twenty-one volunteers (13 females and 8 males) participated, undergoing assessments pre-surgery and nine to 12 months post-surgery. Clinical tests indicated significant reductions in knee pain and improvements in active and passive extension post-surgery. TKA resulted in decreased pain, extension deficits, and functional assessments, with lower scores on the WOMAC questionnaire. A gait analysis showed post-surgery improvements in gait speed (5.8%), cycle time (−4.8%), step time (4.4%), double limb support time (−11.1%), step (4.4%) and stride (6.3%) lengths, and step (5.1%) and stride (5.0%) cadences. Comparisons between surgical side and limb dominance indicated significant differences in gait speed, stance, swing and step times, double limb support time, step and stride lengths, and step cadence. The non-dominant limb demonstrated greater improvements across most parameters compared to the dominant limb. These findings emphasize the importance of considering the limb dominance of patients with knee osteoarthritis when evaluating post-TKA function. These conclusions can be helpful for personalized rehabilitation programs, allowing tailored interventions for individuals undergoing knee surgery.

Double Step Technique for Accurate Microwave High Attenuation Measurements

Double Step Technique for Accurate Microwave High Attenuation Measurements

محاكاة تدفق السوائل النانوية الصفائحية على خطوة ساخنة مزدوجة مواجهة للخلف

This research focuses on heat transfer enhancement by separating flow over a double backward-facing step using nanofluid. To conduct this research, a numerical model was constructed using the ANSYS Workbench, and the governing equations were solved using the realizable k-ε model with a second-order upwind scheme. Three different types of base fluid (water, engine oil, and ethylene glycol) with nanoparticles (AL2O3, TiO2, and Cu) were used for Reynolds numbers ranging from 200 to 1000. The constant heat flux of the 2000 W/m2 boundary condition is considered on the lower wall. The effect of nanoparticle material, nanoparticle concentrations, nanoparticle sizes, and Reynolds numbers on the Nusselt number is investigated. Two different approaches for estimating nanofluid thermal conductivity and viscosity have been used. The numerical code results were verified with previous numerical data. The results showed that the peak of the Nusselt number occurs immediately after the steps. The results demonstrated a significant improvement in the heat transfer performance of nanofluids, especially Cu/engine oil nanofluids, compared to conventional base fluids with other nanoparticles. It was noticed that the Nusselt number increases with decreasing nanoparticle diameter and also with increasing Reynolds number.

Convenient Access to a N,N’‐bis(2,6‐terphenyl) Substituted N‐Heterocyclic Carbene

AbstractThe efficient synthesis of a N,N’‐bis(2,6‐terphenyl) substituted N‐heterocyclic carbene (NHC) is reported. The gain in efficiency and total yield, compared to traditional synthesis, is the result of a high yielding and scalable double Suzuki coupling step, affording a 2,6‐terphenyl aniline, catalyzed by a Pd β‐diketiminate complex. A stereoelectronic study revealed the new NHC to be very similar to the only other N,N’‐bis(2,6‐terphenyl) substituted NHC. Application to the stabilization of Group 13 trihydrides gives acceptable outcomes but inferior to those observed when the bulky IPr* NHC is deployed.

Microstructural development in a hot rolled multi-phase steel

The present work describes the development of microstructures in multi-phase steels with minimum ultimate tensile strength (UTS) in the range of 750–800 MPa. A relatively leaner composition was designed to achieve the strength, and with two compositions, the UTS values of about 750 MPa and 800 MPa were achieved. In both cases, multi-phase microstructures were developed, which consisted of ferrite, bainite and martensite. Bainite was the major phase in these microstructures. The cooling rate played a vital role. Ferrite was observed to form as the major phase along with islands of bainite at a cooling rate of 2 °C/s or less than that. The desired amount of bainite phase could be obtained at and above a cooling rate of 20 °C/s. A double step cooling strategy was applied to achieve the desired multi-phase microstructure. After the completion of hot rolling at around 850 °C, a fast cooling to a temperature of 580 °C and holding there for a duration of 5–12 s led to the formation of ample bainite in the microstructure, followed by transformation of remaining austenite into martensite during the second step cooling at 250 °C.

Utilizing sustainable trichalcogenide semiconductor BaS:MnS:DyS to maximize supercapacitor efficiency via innovative single-source precursor method

Electrochemical energy storage has garnered significant attention from the scientific community and energy stakeholders due to its prospective applications, including e-vehicles. The present work aims to improve charge-storage device performance through the use of the novel semiconductor chalcogenide BaS:MnS:DyS, which is synthesized by chelating with diethyldithiocarbamate ligand. Remarkable photo-activity was detected for this semiconductor with an energy band gap of 3.59 eV. With mixed crystalline phases, the generated chalcogenide had an average crystallite size of 18.73 nm, exhibiting auspicious crystallinity. Furthermore, infrared spectroscopy was used to identify metallic sulfide connections, which were found to range between 400 and 967 cm−1. Double step thermal decomposition was confirmed by thermogravimetric analysis. A greater volume-surface area ratio and the existence of many sites were suggested by particles with varying shapes and a fusion resembling rod. With a background electrolyte of 1 M KOH, a conventional three-electrode setup was used to assess the BaS:MnS:DyS electrochemical performance. With a specific power density of 10826.7 W kg−1 and a specific capacitance of up to 824.13 F g−1, BaS:MnS:DyS is an excellent electrode material for energy storage applications. This noteworthy electrochemical performance was further substantiated by the similar series resistance (Rs) = 0.77 Ω.

Increased concentrations of P2X7R in oligodendrocyte derived extracellular vesicles of Multiple sclerosis patients

Activation of the purinergic receptor P2X7 (P2X7R) is believed to be deleterious in autoimmune diseases and it was hypothesized to play a role in the pathogenesis of MS. P2X7R is an ATP-gated non-selective cationic channel; its activation can be driven by high concentrations of ATP and leads to the generation of large, cytolytic conductance pores. P2X7R activation can also result in apoptosis as a consequence of the activation of the caspase cascade via P2X7R-dependent stimulation of the NLRP3 inflammasome. We measured P2X7R in oligodendrocyte derived extracellular vesicles (ODEVs) in MS patients and in healthy subjects.Sixty-eight MS patients (50 relapsing-remitting, RR-MS, 18 primary progressive, PP-MS) and 57 healthy controls (HC) were enrolled. ODEVs were enriched from serum by a double step immunoaffinity method using an anti OMGp (oligodendrocyte myelin glycoprotein) antibody. P2X7R concentration was measured in ODEVs lysates by ELISA.One–way Anova test showed that P2X7R in ODEVs is significantly higher in PP-MS (mean: 1742.89 pg/mL) compared both to RR-MS (mean: 1277.33 pg/mL) (p < 0.001) and HC (mean: 879.79 pg/mL) (p < 0.001). Comparison between RR-MS and HC was also statistically significant (p < 0.001). Pearson's correlations showed that P2RX7 in ODEVs was positively correlated with EDSS (p = 0.002, r = 0.38, 0.15–0.57 95% CI) and MSSS (p = 0.004, r = 0.34, 0.12–0.54 95% CI) scores, considering MS patients together (PP-MS + RR-MS) and with disease duration in PP-MS group (p = 0.02, r = 0.53, 0.09–0.80 95% CI).Results suggest that ODEVs-associated P2X7R levels could be a biomarker for MS.

RNA Complexes with Nicks and Gaps: Thermodynamic and Kinetic Effects of Coaxial Stacking and Dangling Ends.

Multiple RNA strands can interact in solution and assume a large variety of configurations dictated by their potential for base pairing. Although duplex formation from two complementary oligonucleotides has been studied in detail, we still lack a systematic characterization of the behavior of higher order complexes. Here, we focus on the thermodynamic and kinetic effects of an upstream oligonucleotide on the binding of a downstream oligonucleotide to a common template, as we vary the sequence and structure of the contact interface. We show that coaxial stacking in RNA is well correlated with but much more stabilizing than helix propagation over an analogous intact double helix step (median ΔΔG°37°C ≈ 1.7 kcal/mol). Consequently, approximating coaxial stacking in RNA with the helix propagation term leads to large discrepancies between predictions and our experimentally determined melting temperatures, with an offset of ≈10 °C. Our kinetic study reveals that the hybridization of the downstream probe oligonucleotide is impaired (lower kon) by the presence of the upstream oligonucleotide, with the thermodynamic stabilization coming entirely from an extended lifetime (lower koff) of the bound downstream oligonucleotide, which can increase from seconds to months. Surprisingly, we show that the effect of nicks is dependent on the length of the stacking oligonucleotides, and we discuss the binding of ultrashort (1-4 nt) oligonucleotides that are relevant in the context of the origin of life. The thermodynamic and kinetic data obtained in this work allow for the prediction of the formation and stability of higher-order multistranded complexes.

Examination time-distance characteristics of gait and pelvic kinematics in individuals with Diabetic polyneuropathy: a case-control study

ABSTRACT Background Diabetic Peripheral Neuropathy (DPN) disrupts body and movement biomechanics, increases mechanical stress during walking, and predisposes individuals to injuries owing to the repetitive effects of these stresses. Aims This study aimed to assess and compare the impact of neuropathy on gait and pelvic kinematics in individuals with DPN. Methods This case-control study included two groups: 23 individuals diagnosed with DPN aged between 35–70 and 23 healthy individuals aged–35–70. The BTS-G, a wireless motion sensor, was used to assess the time-distance characteristics of walking in all participants. The system analyzed data pertaining to walking speed, cadence, percentages of stance and swing phases, durations of walking cycles, double-step lengths, pelvic tilt, obliquity, and rotation symmetries. Results There were no statistically significant differences between the groups in cadence, left and right stance phase percentages, or left and right swing phase percentages (p > 0.05). However, significant differences were observed between the groups in terms of speed, left and right walking cycle durations, and left and right double-step lengths (p < 0.05). Additionally, no statistically significant difference was found between the groups in pelvic tilt symmetry and left and right pelvic tilt range of motion values (p > 0.05). Nevertheless, significant differences were identified between the groups in pelvic obliquity symmetry, pelvic rotation symmetry, left and right pelvic obliquity range of motion, and left and right pelvic rotation range of motion values (p < 0.05). Conclusions The findings of this study suggest that individuals with DPN exhibit decreased walking speed, prolonged gait cycle duration, increased double step length, and reduced pelvic obliquity and rotation range of motion.

Numerical investigations of fluid flow and heat transfer in double forward facing step in the presence of a fin

Fluid flow overstep has many interesting physics such as flow separation, reattachment, recirculation, development of wall boundary layer, and primary and secondary vortices are few of them. Numerical simulation of this situation has been successfully employed for more than 3 decades. In the present investigation, a fin is introduced in the flow passage and explored its role in fluid flow and heat transfer. A fin is attached either to the top wall or bottom wall is considered and its position and size are varied. Further Reynolds number is also varied by assuming the flow is turbulent. Commercial software ANSYS Fluent is used for conducting the numerical simulation. For all the cases results were reported for flow physics and heat transfer in terms of streamline contour, isotherm, local Nusselt number as well as average Nusselt number. It is observed that the local Nusselt number is varied to a maximum value and further is decreased in the downstream direction. By varying the Reynolds number average Nusselt number can be improved from 20% to 85%. The fin size influences to increase of the average Nusselt number if it exceeds 0.3H. However, beyond a certain distance, the location of the fin is less influenced for improving the average Nusselt number. 22% hike in average Nusselt number is achieved when fin is located at top wall when compared to no fin case. However, the peak Nusselt number always occurred at the reattachment of the primary vortex.

Enhancement of thermal energy transfer behind a double consecutive expansion utilizing a variable magnetic field

This research focuses on utilizing non-uniform magnetic fields, induced by dipoles, to control and enhance thermal energy transfer in a two-dimensional cooling conduit including a double backward-facing step. The presence of electronic equipment along the straight channel path creates such arrangements, and cooling is often ineffective in the corners of the formed steps. The use of a non-constant magnetic field is a passive technique to improve the cooling rate in these sections without changing the internal geometry, thereby increasing the heat transfer rate. A commercial software based on the finite volume technique is employed to solve the governing equations of fluid flow and heat transfer. Multiple parameters are examined in this study, including the flow Reynolds number (12.5–50), dipole location and strength (0.1–5 A-m), and the number of dipoles (single or double). The results indicate that all of these parameters have a significant impact on the thermal energy transfer. The results of the study show that a single dipole increase the average heat transfer by about 22%, two magnetic fields by 40%, the strength of the magnetic source by 24% with respect to the non-magnetic field in the present study.

Synchronous Electrochromism and Electrofluorochromism in a Zirconium Pyrenetetrabenzoate Metal–Organic Framework

AbstractRedox‐active materials that exhibit both electrochromism and electrofluorochromism have great potential as multifunctional elements in optoelectronics. Here, in situ spectroelectrochemistry is presented on NU‐1000, a zirconium pyrenetetrabenzoate metal–organic framework. A thin film of NU‐1000 exhibits reversible color changes between light yellow and dark blue when subjected to an alternating electrochemical potential. In situ fluorescence excitation‐emission spectral mapping elucidates a dominant blue emission of highly fluorescent electrochromic NU‐1000 that is being quenched via an oxidation reaction. Density‐functional theory calculations reveal the forbidden optical transition between the singly occupied molecular orbital (SOMO) and the lowest unoccupied molecular orbital (LUMO) in the oxidized linker as the cause of the quenching. Double potential step chronoamperometry measures response times as fast as a dozen seconds and excellent switching stability over 500 cycles without noticeable attenuation of the color contrast. These findings provide valuable insight into the electrochromism and electrofluorochromism in metal–organic frameworks, offering exciting opportunities for developing advanced multifunctional porous materials with potential applications in optoelectronics and sensing.

Evaluating the Atypical Aging Potential Development in Sparkling Wines Can Be Achieved by Assessing the Base Wines at the End of the Alcoholic Fermentation.

Traditional sparkling wine production is a lengthy and costly process, involving a double fermentation step and a period of aging sur lie; thus, monitoring quality during the key manufacturing stages is crucial. The effects of the second fermentation on the development of 2-aminoacetophenone (AAP), the main marker of the atypical aging (ATA) defect, were investigated on 55 base wines (BWs) and corresponding sparkling wines (SWs) produced in an experimental winery. While the AAP content of the SWs was observed to be higher than the BWs, it was found that an artificial aging test carried out on the BWs could be a good predictor of ATA development in SWs. Further, the antioxidant capacity of the SWs was noticed to correlate well with the potential AAP formed during accelerated aging. Finally, an analysis of covariance (ANCOVA) model of linearization capable of predicting AAP formation in SWs using the data obtained from the corresponding BWs was created.

Convergence of a double step scheme for a class of second order Clarke subdifferential inclusions

In this paper we deal with a second order evolution inclusion involving a multivalued term generated by a Clarke subdifferential of a locally Lipschitz potential. For this problem we construct a double step time-semidiscrete approximation, known as the Rothe scheme. We study a sequence of solutions of the semidiscrete approximate problems and provide its weak convergence to a limit element that is a solution of the original problem.

Relationship between respiratory muscle strength and dynamic balance in older persons requiring care or support: Focusing on the maximal single step length test and maximal double step length test as dynamic balance indices

BackgroundFalls are a major health problem. The relationship between dynamic balance related to falls and respiratory muscle strength related to sarcopenia and frailty is poorly understood. Research questionHow do dynamic balance measures, such as maximal single step length test (MSL) and maximal double step length test (MDST), and respiratory muscle strength measures, such as maximal inspiratory (PImax) and maximal expiratory (PEmax), related to the requirement for long-term care or support in older people who live in the community? MethodsThis was a cross-sectional study of 39 older people (17 men, 22 women) aged ≥ 65 years community-dwelling who were certified as requiring long-term care or support under the Japanese system. The participants’ PImax, PEmax, MSL, and MDST results were recorded. The measurement data were evaluated using Pearson’s correlation coefficients and multiple regression analysis. ResultsMDST showed a positive correlation with PImax (r = 0.430, p = 0.006) but no correlation with PEmax. MSL showed no correlation with PImax or PEmax. A positive correlation was found between MDST and MSL (r = 0.851, p < 0.001), and multiple regression analysis with MDST as the dependent variable and PImax and MST as independent variables showed significant differences for MSL (p < 0.001) and PImax (p = 0.027). SignificanceIn older people requiring long-term care or support, MDST had a greater association with inspiratory muscle strength compared with MSL. These results suggest the importance of inspiratory muscle strength training and MDST assessment in the prevention of falls in older people requiring long-term care or support.

Observing temporary changes in gait using a mobile phone

The purpose of the article is to analyze temporary changes in human gait, the parameters of which are recorded using the accelerometer of a mobile phone in everyday use. The work presents trends in the field of personalized medicine and monitoring the health of employees in the manufacturing sector based on wearable and mobile devices. The features of collecting and processing data on a person’s gait using a mobile phone are presented, which act as a comprehensive assessment of human health parameters. The results of a year-long research of changes in human gait are presented. Daily, weekly and annual trends are identified. The research analyzed mobile phone accelerometer time series representing double steps during gait. When constructing trends, the maximum value of the cross-correlation function of data segments was used. Data segmentation was carried out according to the length of the double step. Based on the results of the research, an assumption is made about the possibility of recording individual characteristics of the functioning of the human musculoskeletal system using a mobile phone and conducting further research in order to accumulate statistical material and identify the relationship between a person’s lifestyle and changes in gait parameters.

Three Stage Helical Gearbox: A Review of Materials - Scope and Challenges

Many research articles on various helical gearbox stages are accessible in reputable journals. The majorities of earlier research, despite the fact that triple step helical gearboxes have several benefits, were confined on single step and double step helical gears. Lately, most researching experts who work in this field have started paying close attention to the importances of three stage helical gearboxes. Throughout this research, authors seek to carry out an exhaustive evaluation of the current triple step helical transmission articles for examining the most widely used survey designs, approaches, tools &amp; techniques. The above investigation expansively analysed 315 journal articles on helical gearbox various stages and then used content analysis procedure with an inductive method of research for carrying out an organized review of 45 literatures on three step helix transmission box that appeared in different scientific publications over the preceding two decades. Apart from this; the study presents a broad assessment of currently utilized materials, several future possibilities and problems in employing different materials for various parts of gearbox and its casing. This important research finding indicates there’s an enormous potentiality towards dominating the area of research as well as continuing more chances for exploring growth of three stage helical gearboxes, which provides novel career opportunities for both experts and industrial professionals.

Simultaneous electrochemical sensing of dopamine and uric acid with the aids of chemometric methods

It is important to simultaneously detect dopamine (DA) and uric acid (UA) for health monitoring and disease diagnostics. Studies shows that bimetallic catalysts with synergistic effect have a better catalytic performance in the simultaneous determination. Herein, a composite of N-doped CoFe on carbon matrix doped with ▪ (CoFe/▪/NC) was prepared by pyrolyzing a metal-organic framework. Then the composite was modified on glassy carbon electrodes to simultaneously detect DA and UA. The study of double potential step chronoamperometry showed that the diffusion coefficients and the catalytic rate constants for UA were less than those of DA. Since the electrochemical signals related to DA and UA interfere with each other, the concentration calibration curve of one component would distort if the concentration of coexisting component varied. The simultaneous detection was executed via differential pulse voltammetry with the aid of chemometric methods. The models established by partial least squares regression analysis have little help for the simultaneous detection, especially for the concentration of UA in the samples. The models build by back propagation artificial neural network can realize the simultaneous determination with only 4 neurons in three-layer network. DA and UA in normal human serum were detected by the CoFe/▪/NC electrode with the aids of chemometrics.