Ra Values Research Articles

Opioid-free anesthesia with ultrasound-guided quadratus lumborum block in the supine position for lower abdominal or pelvic surgery: a randomized controlled trial

In the past, quadratus lumborum block (QLB) was mostly used for postoperative analgesia in patients, and few anesthesiologists applied it during surgery with opioid-free anesthesia (OFA). Consequently, it is still unclear whether QLB in the supine position can provide perfect analgesia and inhibit anesthetic stress during surgery under the OFA strategy. To observe the clinical efficacy of ultrasound-guided quadratus lumborum block (US-QLB) in the supine position with OFA for lower abdominal and pelvic surgery. A total of 122 patients who underwent lower abdominal or pelvic surgery in People’s Hospital of Wanning between March 2021 and July 2022 were selected and divided into a quadratus lumborum block group (Q) (n = 62) and control group (C) (n = 60) according to the random number table method. Both groups underwent general anesthesia combined with QLB in the supine position. After sedation, unilateral or bilateral QLB was performed via the ultrasound guided anterior approach based on images resembling a “human eye” and “baby in a cradle” under local anesthesia according to the needs of the operative field. In group Q, 20 ml of 0.50% lidocaine and 0.20% ropivacaine diluted in normal saline (NS) were injected into each side. In group C, 20 ml of NS was injected into each side. The values of BP, HR, SPO2, SE, RE, SPI, NRS, Steward score, dosage of propofol, dexmedetomidine, and rocuronium, the number of patients who needed remifentanil, propofol, or diltiazem, puncture point, block plane, duration of anesthesia, catheter extraction, and wakefulness during the operation were monitored. There were no significant differences in the general data, number of cases requiring additional remifentanil, propofol, or diltiazem treatment, as well as puncture point and puncture plane between the two groups (P > 0.05). HR, SBP, and DBP values were higher in group Q than in group C at T1; HR, SPI, and SE, while RE values were lower in group Q than in group C at T3, SE, and RE; the Steward score was higher in group Q than in group C at T4 and T5, and the difference was statistically significant (P < 0.05). The extubation and awake times were lower in group Q than in group C, and the difference was statistically significant (P < 0.05). The SE, RE, and SPI values were lower at T1, T2, T3, and T4 than at T0. The Steward scores at T4 and T5 were higher in group Q than in group C, and were lower than at T0, with a statistically significant difference (P < 0.05). There were significant differences in the effectiveness of postoperative analgesia between the two groups at t1, t3 and t4 (P < 0.05). US-QLB in the supine position with OFA is effective in patients undergoing lower abdominal or pelvic surgery with stable intraoperative vital signs, complete recovery and better postoperative analgesia.

An experimental study of Lode angle impact on the rock failure procession based on acoustic emission

The laws of acoustic emission (AE) before and during rock failure are different under different stress states. In this article, a new multi-functional true triaxial geophysical (TTG) apparatus was applied to analyze the AE law of sandstone under different stress paths. The results show that (1) with the increase of Lode angle, the tensile fractures in the sandstone increase initially, followed by a decrease. The number of AE decreases initially, followed by an increase, while the average energy of AE signal increases initially, followed by a decrease. (2) During the loading process, the IB values of rock can be divided into wave type, band type and mixed type, which represent crack propagation process driven by external force, self-driving and mixed driving. It can provide a basis for early warning of underground engineering construction disasters. (3) The variation characteristics of RA and AF in rock failure process show the corresponding relationship with IB value. The RA value corresponding to the IB value of band, wave and distribution type distribution mainly concentrated around 0.05, 0.03 and widely distributed, respectively. According to the value of RA, the types of cracks show different characteristics under different driving forces. (4) With the increase of Lode angle, the failure types of rocks change from single oblique fracture (− 30°) to double-X-type fracture (10°), and finally changes to single-X-type fracture when Lode angle is 30°. The fracture angle of rock decreases initially, followed by an increase with the increase of Lode angle. Therefore, it is important to explore the AE law of rock failure process under different stress states for the early warning of underground engineering construction disasters, and can provide a guidance for the application of human underground space.

Effect of an Effervescent Multivitamin on Color and Surface Roughness of Micro-Hybrid Dental Resin Composites.

The use of multivitamins has become widespread globally, yet there is a scarcity of studies investigating their impact on resin composite restorations. This study aimed to evaluate the effect of an effervescent multivitamin tablet on micro-hybrid dental resin composites' surface roughness and color. Fifty disc-shaped samples (8 × 2 mm, shade A2; n = 10) were prepared and polished using five different micro-hybrid resin composites (Pergamon, Dentac, Turkey; Estelite Posterior, Tokuyama, Japan; Geanial Anterior, GC, Japan; Charisma Opal, Kulzer, Germany; Beautifil II, Shofu, USA). Samples were immersed in 200 mL water to one effervescent multivitamin tablet (Redoxon Triple Action, Bayer) at 24 °C for 2 min a day in 24 h intervals for 30 days. All samples' surface roughness (Ra) and ΔE(L*a*b) measurements were recorded at the beginning and end of the 30 days. The Wald chi-square and a two-way ANOVA were used for statistical analysis (significance level p < 0.05). The resin composite type and exposure to the multivitamin had a statistically significant effect on Ra values (p < 0.05). The resin composite type had a statistically significant effect on ΔE values, likely due to the higher mean value of BII (p = 0.040). The surface roughness and color of resin composites can be affected by multivitamins with a pH value of 3.0. Therefore, it is important to consider the patient's routine vitamin intake during resin composite selection. Additional research is required to explore the properties of different dental restorative materials.

Modeling surface quality, cost and energy consumption during milling of alloy 2017A: a comparative study integrating GA-ANN and RSM models

ABSTRACT The use of simple machining features to determine cutting parameters and the machining process is limited, as parts may contain complex features interacting with each other. This study, therefore, focuses on pocket/groove features and proposes an approach integrating hybrid GA-ANN and RSM algorithms to predict surface quality, cost, and energy consumption (QCE). A parametric study was carried out, taking into account the swarm population size (pop) and the number of neurons (n) in the hidden layer, to find the best prediction using the hybrid GA-ANN algorithm. The results showed the highest correlation values (R2) for all output variables (above 0.97%). The study also revealed that the allocation of machining strategies and sequences can have a significant impact on energy consumption, with a 99.25% variation between minimum and maximum values. Mean square error (MSE) data confirmed the effectiveness of the GA-ANN model. Compared with RSM model predictions, energy consumption (Etot), cost (Ctot), and surface quality (Ra) values all showed statistically significant increases of 90.9%, 96.55%, and 40.18%, respectively. This study highlights the potential of the GA-ANN hybrid approach for multi-criteria prediction (quality, cost, and energy: QCE) in comparison with the RSM method, offering potential improvements for machining 2017A alloy.

Are Hansen solubility parameters relevant in predicting the post-treatment effect on polyamide-based TFC membranes?

This study investigates the impact of solvent post-treatment on polyamide-based thin film composite (TFC) membranes, specifically examining the effect on commercial nanofiltration (NF) and reverse osmosis (RO) membranes. Na2SO4 rejection and increase in pure water permeance (PWP) were considered as the output parameters. The disparity in Hansen solubility parameters (HSP) between the post-treatment solution and the polyamide layer of the TFC membrane, denoted by Ra, is well adapted to understand the enhancement in water permeance through the membranes upon treatment. Aqueous solutions of dimethylformamide with a Ra value of 4, acetonitrile with a Ra value of 8.3, and ethanol with a Ra value of 12.7 were used as the post-treatment solutions. Our experimental design, based on the Box-Behnken design of Response Surface Methodology, incorporates variables such as the concentration of the solvent in the solution (% v/v), Ra value, and treatment time (s). Our findings demonstrate that the effect of post-treatment on the TFC membranes is not governed by the Ra value. Notably, while the post-treatment with the aqueous solution of acetonitrile, 80% v/v for 30 s, had considerable effects on NF membranes (124.5% enhancement in PWP; reduction of 3.5% in Na2SO4 rejection), its impact on RO membranes was negligible. Several factors explain this discrepancy, including the limitations of the HSP model for composite polymers, the inaccuracy of the PWP or salt rejection as a swelling indicator, variations in the HSP values of the polyamide layers for different membranes, and possible modifications in the interface between the support membrane and the polyamide layer. In summary, our study provides insights into the complex interactions between solvents and composite membranes, indicating that HSP alone is not a decisive factor in predicting post-treatment effects on polyamide-based TFC membranes.

Conjugate free convection in a non-uniform heating walled enclosure filled by ternary hybrid nanofluid under magnetic field

A study was conducted using numerical simulations to analyse the behaviour of heat transfer in a square enclosure filled with a ternary hybrid nanofluid in the occurrence of a magnetic field. The flow in the enclosure is characterised by steady and laminar conjugate-free convection. The enclosure has a vertical border with a finite thickness, while the other three borders are assumed to be very thin. The investigation aims to analyse the impact of several key factors on the average Nusselt number using the finite element method. These parameters include the volume fraction of ternary hybrid type nanoparticles (ranging from 0 to 0.03), Rayleigh number (varying from 103 to 106), solid wall thickness (changing from 0.1 to 0.3), Hartmann number (varying from 0 to 100), and the ratio of thermal conductivities (ranging from 0.1 to 10). A notable enhancement in heat transfer is found by employing a ternary hybrid nanofluid. This enhancement becomes more significant for small Rayleigh numbers, where heat conduction governs the primary means of heat transfer. Also, at low levels of Ra, the development of energy transfer strength becomes insignificant in the existence of a magnetic field. This magnetic field effect is primarily controlled by high values of Ra, which consequently leads to an enhancement in the strength of energy transmission.

The Surface Roughness of Contemporary Indirect CAD/CAM Restorative Materials That Are Glazed and Chair-Side-Finished/Polished.

The surface roughness (Ra) of indirect computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated dental restorations is crucial for their long-term durability. This study intended to evaluate the Ra of five different types of contemporary indirect CAD/CAM restorative materials with varying compositions that were glazed and finished/polished. A total of 75 specimens, disc-shaped (10 mm × 2 mm), were obtained from five materials (n = 15) (Tetric CAD, IPS e.max CAD, IPS e.max ZirCAD, CELTRA Duo, and Vita Enamic) and fabricated by CAD/CAM. One of the two surfaces for each specimen was subjected to glazing, while the other surface was subjected to finishing/polishing. The Ra of the two surfaces in micrometers (μm) was evaluated using a Profilometer, while the surface topography was examined using a scanning electron microscope. Using SPSS, the Kruskal-Wallis, post hoc Conover, and Mann-Whitney tests were used to statistically evaluate the data. A comparison of the Ra for the finished/polished surfaces of the five test materials showed significant differences (p < 0.0001). Among the finished/polished surfaces, the mean rank values of Vita Enamic were significantly higher than the other four test materials (p < 0.0001). A comparison of the Ra of glazed surfaces among the five study materials revealed significant differences (p < 0.0001). The Ra for the IPS e.max ZirCAD material was significantly higher than the rest of the four materials (p < 0.001). A comparison of the Ra for two types of surface conditioning within each of the five test materials showed a significant difference (p < 0.05). Only for IPS e.max ZirCAD was the Ra of the glazed surface significantly higher than the finished/polished surface (p < 0.0001). Significant variations in the surface roughness (Ra) were exhibited between the finished/polished and glazed surfaces of the five test materials. Hybrid ceramics showed the highest Ra values for the finished/polished surfaces, and zirconia exhibited the highest Ra values among the glazed surfaces among the tested materials. The Ra values of either finished/polished or glazed surfaces of the test materials were within the clinically acceptable range (0.2-0.5 μm), except for the glazed surface of the zirconia ceramics (0.84 μm).

Effect of Printing Layer Thickness on Optical Properties and Surface Roughness of 3D-Printed Resins: An In Vitro Study.

To investigate the impact of printing layer thickness on the optical properties and surface roughness of various 3D-printed resins manufactured by digital light processing (DLP) and indicated for provisional and definitive restorations. A total of 240 specimens from four different 3D-printing resins-VarseoSmile Crown Plus (Bego; VS), Crowntec (Saremco Dental; CR), GC Temp PRINT (GC Dental; TG), and NextDent C&B MFH (NextDent; ND)-were divided into four groups (n = 60 per group). Each group was further divided into three subgroups (n = 20) according to printing layer thickness (25, 50, and 100 μm). All specimens were subjected to thermocycling with coffee before measurements were taken with a spectroradiometer to calculate color differences. The Kubelka-Munk (K-M) absorption (K) and scattering coefficients (S), translucency parameters (TP), and surface roughness (Ra) values were calculated for each printing layer thickness and compared with those of the 2M2 shade tab (target). The data were analyzed using Mann-Whitney U test, the variance accounted for (VAF) coefficient by Cauchy-Schwarz, and post hoc comparisons using Tukey test (α ≤ .05). S (79% ≤ VAF ≤ 100%) and K (40.45% ≤ VAF ≤ 100%) spectral distribution depended on the wavelength. A 25-μm layer thickness resulted in no significant differences from the 2M2 shade for S (P > .230) and K (P > .200). VS showed significantly different S (P = .004) and K (P = .003) values from those of the shade tab with 50-μm layering thickness, whereas other materials did not show significant differences from the 2M2 shade for S (P > .280) and K (P > .301). The 100-μm layer thickness specimens had significantly different S and K values compared to the 2M2 shade tab (P < .004). TP values of resins with 100-μm layer thickness were significantly lower than resins in 25- and 50-μm layer thicknesses (P < .001). The Ra values of resins increased significantly with 100-μm layer thickness (P ≤ .001). All tested materials, except for VS, showed color properties similar to the target shade when 25- and 50-μm printing layer thicknesses were used. The translucency of resins tended toward an inverse relationship with printing layer thickness. The surface roughness of resins increased significantly with 100-μm layer thickness. However, all resins with a printing thickness of 25 μm showed better color properties and surface roughness.

Comprehensive analysis of heat transfer and pressure drop in square multiple impingement jets employing innovative hybrid nanofluids

This study presents a comprehensive analysis of heat transfer and pressure drop characteristics in square multiple impingement jets utilising a novel class of hybrid nanofluids. This study goes beyond the usual vertical impingement method by looking at the use of oblique impingement in a multiple impinging jet configuration with a hybrid nanofluid. Al2O3–Cu/water with different volume fractions (φhnf) such as 0.1%, 0.33%, 0.75%, and 1.0% are employed as a working fluid. The purpose of the study is to clarify the impact of the jet angle (β), the jet Reynolds number (Re), extended jet height (Ej), and different volume fraction (φhnf) on the heat transfer behaviours of the curved target surface. The jet Reynolds number varies from 8000 to 24,000, and five different jet angles (β = 15 °, 30°, 45°, 60°, 90 °) and three extended jet heights (Ej = 0.2H, 0.4H, and 0.6H) are adopted. Outcomes disclosed that the highest values of Re and φhnf greatly led to an increase in heat transfer rate and pressure drop of the system. It is uncovered that the heat transfer rate of binary hybrid nanofluids enhances with increasing volume fraction from for all jet angles and Re. Results also exposed that the angle of jet, which is 45°, gives a higher Nusselt number compared to other angles proposed in this study, and the maximum boost reaches 35%. Besides, despite the fact that reducing the height of the extended jet yields enhanced heat transfer rates in comparison to other methods, it concurrently results in an elevation in pressure drop. Finally, this research yielding insights that can be applied to improve the efficiency of heat transfer systems in practical applications.

Thermo-entropy analysis of water-FMWCNT nano-fluid flow in a backward-facing channel with obstacle

Thermo hydraulic analysis of nano-fluid flow phenomena through backward-facing channel has currently gained attention of the researchers, and is applied in a variety of engineering applications. Hydro-thermal properties of water/FMWCNT nano-fluid flow in a backward-facing channel embedded with an obstacle under uniform heat flux have been studied numerically with the variations in the values of Reynolds numbers ( Re ) , weight percentage of carbon nano-particle ( wt . % ) , and differently shaped obstacles. The governing equations (continuity, x-momentum, y-momentum, and energy) have been solved using the finite volume approach, and fluent software has been used to visualize the simulation results. Impact of various forms of obstacle (plane, elliptical, and triangular), the ratio of obstacle height to width (A/B), the ratio of obstacle pitch to width ( B 1 / B ) , wt . % , and the values of Re on the different rheological behaviour of nano-fluid flow have been investigated. For all the forms of obstacle configuration, the distributions of velocity streamlines, temperature contours, absolute pressure drop ( Δ p ) , average friction factor ( F ) , local Nusselt number ( Nu ( x ) ) , skin friction coefficients ( c f ( x ) ) , average Nusselt number ( N u avg ), and pumping power ( P ) have been demonstrated for several values of Re ( 1 , 50 and 150 ) , and wt . % ( 0 , 0.12 and 0.25 ) . For several values of Re and wt . % , generations of frictional entropy ( N frictional ) , thermal entropy ( N thermal ) , and Bejan number ( Be ) have been explored. It seems that the presence of obstacle, and the increase in the values of Re , wt . % causes the rise of the values of Δ p , P , and N u avg than the case of smooth channel. Moreover, at wt . % = 0.25 and Re = 150 , it has been found that the % increase in N u avg becomes 47.37 in the case of backward-facing channel with plane obstacle (A/B = 1) as compared to the case of smooth channel. Furthermore, at a constant value of wt . % it has been found that the generation of N thermal decreases but the generation of N frictional entropy increases with the rise in the values of Re .

Machinability and Surface Properties of Cryogenic Poly(methyl methacrylate) Machined via Single-Point Diamond Turning.

Poly(methyl methacrylate) (PMMA), with a glass transition temperature (Tg) over 100 °C, shows good mechanical and optical properties and has broad applications after being machined with single-point diamond turning (SPDT) at room temperature. Because of the high Tg, current efforts mostly focus on optimizing machining parameters to improve workpiece precision without considering the modification of material properties. Cryogenic cooling has been proven to be an effective method in assisting ultra-precision machining for certain types of metals, alloys, and polymers, but has never been used for PMMA before. In this work, cryogenic cooling was attempted during the SPDT of PMMA workpieces to improve surface quality. The machinability and surface properties of cryogenically cooled PMMA were investigated based on the mechanical properties at corresponding temperatures. Nanoindentation tests show that, when temperature is changed from 25 °C to 0 °C, the hardness and Young's modulus are increased by 37% and 22%, respectively. At these two temperature points, optimal parameters including spindle speed, feed rate and cut depth were obtained using Taguchi methods to obtain workpieces with high surface quality. The surface quality was evaluated based on the total height of the profile (Pt) and the arithmetic mean deviation (Ra). The measurement results show that the values of Pt and Ra of the workpiece machined at 0 °C are 124 nm and 6 nm, respectively, while the corresponding values of that machined at 25 °C are 291 nm and 11 nm. The test data show that cryogenic machining is useful for improving the form accuracy and reducing the surface roughness of PMMA. Moreover, the relationship between temperature, material properties and machinability weas established with dynamic mechanical analysis (DMA) data and a theoretical model. This can explain the origin of the better surface quality of the cryogenic material. The basis of this is that temperature affects the viscoelasticity of the polymer and the corresponding mechanical properties due to relaxation. Then, the material property changes will affect surface profile formation during machining. The experimental results and theoretical analysis show that cryogenically cooled PMMA has good machinability and improved surface quality when using SPDT compared to that at ambient temperature.

Self-etching primer versus hydrofluoric acid and air-abrasion: effects on flexural and resin bond strengths of resin-based CAD/CAM material

This study aimed to evaluate the effect of self-etching primer (Monobond Etch & Prime; MEP), hydrofluoric acid (HF), and air-abrasion (A) protocols on shear bond strength (SBS) of resin cement and flexural strength (FS) of nanoparticle-filled resin-based CAD/CAM material. Bar- and rectangular-shaped specimens (n = 130 for each) were obtained from a resin-based material (Cerasmart 270). The specimens were divided into 13 subgroups according to surface treatments: Control (C); HF for 60, 90, and 120 s; MEP for 60, 90, and 120 s; air-abrasion for 10, 15, and 20 s; air-abrasion followed by HF; air-abrasion followed by MEP; HF followed by MEP. Surface roughness (Ra) values were measured using a profilometer (Surftest SJ-210) by applying 9 readings per specimen. One specimen per group was examined by atomic force microscopy (AFM; Multimode 8) in a 20 μm × 20 μm area, and scanning electron microscopy (SEM; EVO LS-10) under ×1000 magnification. FS and SBS data were obtained using a universal test device (Marestek) at a crosshead speed of 1 mm/min. Air-abraded groups showed the highest Ra (A10: 1.331 ± 0.213; A15: 1.409 ± 0.110; A20: 1.491 ± 0.111; A + HF: 1.415 ± 0.138; A + MEP: 1.309 ± 0.071 μm) and the lowest FS values (A10: 122.59 ± 16.80; A15: 118.94 ± 11.74; A20: 117.22 ± 11.18; A + HF: 114.42 ± 18.09; A + MEP: 128.98 ± 19.74 MPa). FS values of HF- and/or MEP-applied groups were statistically similar to the control group (C: 167.37 ± 27.02; HF60: 186.74 ± 30.66; HF90: 162.79 ± 29.31; HF120: 184.11 ± 17.18; MEP60: 171.98 ± 29.65; MEP90: 162.49 ± 20.38; MEP120: 173.55 ± 22.50; HF + MEP: 175.09 ± 21.64 MPa). SBS values of MEP-applied groups were higher than those of HF-etched groups with the same duration. Significant differences in SBS values were found after etching protocols with different durations (HF60: 4.14 ± 0.64; HF90: 4.48 ± 0.33; HF120: 6.76 ± 1.65; MEP60: 6.24 ± 1.23; MEP90: 9.92 ± 1.25; MEP120: 10.22 ± 1.27 MPa). Prolonged MEP application (90 s and 120 s) can be the preferred surface treatment for resin-based CAD/CAM materials. However, air-abrasion may adversely affect its mechanical properties.

Steady and Unsteady Dynamics of Magneto-Nanofluidic Flow in a Bottom-Heated Top-Cooled Recto-Triangular Thermal System

This work numerically explores the evolution flow features during the journey through unsteady to steady dynamics in a magneto-nanofluidic thermal system of recto-triangular shape. This system, which is partially heated using the triangular surface and employs a top-cooling configuration, features an upper rectangular and a lower triangular part. The study addresses laminar flow for various Rayleigh numbers (Ra) up to 105 considering uniform magnetic fields at different inclination angles and utilizing a 0.1% nanoparticle concentration (fixed) CuO-water nanofluid along with a finite element-based solver. The results reveal the formation of multi-vortical structures with varying numbers of circulation cells. The most important observation is the transformation of cells from a four-cell configuration to a one-cell configuration, and finally to a two-cell configuration as Ra changes from 103 to 104 to 105 without a magnetic field. The one-cell structure sustains over a narrow range of Ra and is sensitive to the Hartmann number (Ha). The inclined magnetic fields have a severe impact on the flow structure. Starting from a quiescent state and progressing through the unsteady flow stages, the system rapidly reaches a steady state under different temperature differences (simulated by Ra), except for a few exceptions of Ra and Ha values. The analysis of the unsteady stages of flow development provides deeper insights into the dynamics of multi-cellular flows.

Entropy generation for thermo-magnetic fractional order convective flow in complex porous enclosures: a numerical study

PurposeThis study aims to analyze the impact of fractional derivatives on heat transfer and entropy generation during transient free convection inside various complex porous enclosures, such as triangle, L-shape and square-containing wavy surfaces. These porous enclosures are saturated with Cu-water nanofluid and subjected to the influence of a uniform magnetic field.Design/methodology/approachIn the present study, Darcy’s model is used for the momentum transport equation in the porous matrix. Additionally, the Caputo time fractional derivative is introduced in the energy equation to assess the heat transfer phenomenon. Furthermore, the total entropy generation has been computed by combining the entropy generation due to fluid friction (Sff), heat transfer (Sht) and magnetic field (Smf). The complete mathematical model is further simulated using the penalty finite element method, and the Caputo time derivative term is approximated using the L1 scheme. The study is conducted for various ranges of the Rayleigh number (102≤Ra≤104), Hartmann number (0≤Ha≤20) and fractional order parameter (0<α<1) with respect to time.FindingsIt has been observed that the fractional order parameter α governs the characteristics of entropy generation and heat transfer within the selected range of parameters. The Bejan number associated with heat transfer (Beht), fluid friction (Beff) and magnetic field (Bemf) further demonstrate the dominance of flow irreversibilities. It becomes evident that the initial evolution state of streamlines, isotherms and local entropy varies according to the choice of α. Additionally, increasing Ra values from 102 to 104 shows that the heat transfer rate increases by 123.8% for a square wavy enclosure, 7.4% for a triangle enclosure and 69.6% for an L-shape enclosure. Moreover, an increase in the value of Ha leads to a reduction in heat transfer rates and entropy generation. In this case, Bemf→1 shows the dominance of the magnetic field irreversibility in the total entropy generation.Practical implicationsRecently, fractional-order models have been widely used to express numerous physical phenomena, such as anomalous diffusion and dispersion in complex viscoelastic porous media. These models offer a more accurate representation of physical reality that classical models fail to capture; this is why they find a broad range of applications in science and engineering.Originality/valueThe fractional derivative model is used to illustrate the flow pattern, heat transfer and entropy-generating characteristics under the influence of a magnetic field. Furthermore, to the best of the author’s knowledge, a fractional-derivative-based mathematical model for the entropy generation phenomenon in complex porous enclosures has not been previously developed or studied.

Evaluating the Efficacy of Continuous Water-Cooling 115-Watt 6.78-MHz Monopolar RF Therapy for Fine Wrinkle Reduction.

Cosmetic procedures using radiofrequency (RF) technology have garnered significant attention as noninvasive approaches to skin rejuvenation and wrinkle reduction. This study investigates the efficacy of RF therapy in enhancing skin texture, firmness, and appearance. By harnessing the 6.78-MHz "VolNewMer" RF device, skin aging concerns, particularly in terms of skin roughness, laxity, and wrinkles, can be treated. This study engaged a cohort of 50 participants seeking wrinkle reduction and skin-lifting treatments. Employing noninvasive methods, the efficacy of RF therapy was evaluated immediately posttreatment and 1-month posttreatment. Skin roughness was quantified using a computer-based analysis of standardized 3D scanner images, capturing uniform lighting and angles to ensure accurate measurements. Among the 45 participants who completed the study, significant improvements in skin roughness were observed. The average roughness (Ra) value decreased from 16.71 to 11.88 arbitrary units immediately posttreatment, signifying a 28.42% enhancement. At the 1-month follow-up, the Ra value further decreased to 12.33 arbitrary units, reflecting a sustained 26.23% improvement. However, 16 participants exhibited even greater improvements at 1 month than immediate. RF therapy's profound impact on skin tightening and rejuvenation is rooted in its ability to trigger immediate collagen contraction, bolstering skin elasticity. The dual-phase process of immediate and delayed skin improvement underscores the intricate interplay between thermal stimulation and collagen remodeling. Optimal energy levels and controlled endpoint monitoring ensure safe and effective RF treatments. The use of the VolNewMer device tips and sliding technique contributes to patient comfort and treatment precision.

Integrating response surface methodology and machine learning for analyzing the unconventional machining properties of hybrid fiber‐reinforced composites

AbstractThe aim of this investigation was to delve into the impact of abrasive water jet machining (AWJM) process variables on the surface roughness (Ra) and kerf angle (Ka) of hybrid fiber‐reinforced polyester composites. Utilizing both response surface methodology (RSM) and artificial neural network (ANN) prediction models, the study sought to optimize the input parameters for abrasive water jet machining, specifically in the context of paddy straw and PALF‐reinforced polyester hybrid composites. The process parameters targeted for optimization included the abrasive flow rate, traverse rate, and standoff distance during AWJM. The investigation identified an optimal combination of AWJM parameters that effectively meets the practical requirements for machining hybrid fiber‐reinforced polyester composites. According to the RSM, the suggested optimal values for the process parameters are an abrasive flow rate set at 300 g/min, traverse speed at 110 mm/min, and standoff distance at 1 mm. The ANN exhibited robust predictive capabilities, achieving high R2 scores of 0.932 and 0.962 for surface roughness and kerf angle, respectively. To enhance the performance of abrasive water jet machining and minimize surface roughness and kerf angle, the researchers conducted an optimization of the process parameters. Subsequently, confirmation experiments were executed to validate the predictive model and fine‐tune the set of process parameters for practical application.Highlights Investigated AWJM impact on Ra value and kerf angle of hybrid composites. Used RSM and ANN models for parameter optimization in biocomposite. Optimal AWJM parameters: AFR (300 g/min), TS (110 mm/min), and SOD (1 mm). ANN showed strong predictions: R2 scores 0.932 (Ra) and 0.962 (Ka). Confirmation experiments validated the predictive model for applications.

Uterine Arteriovenous Malformation, Grey- Scale and Colour Doppler findings: A Case Report and Review

Introduction: Uterine arteriovenous malformations can either be congenital or acquired and are rare vascular disorders seen in women of child bearing age, with varied presentation. The clinical features range from being asymptomatic to life threatening haemorrhage. Imaging, particularly grey scale and color Doppler ultrasonography play a major role in the prompt diagnosis of this condition as the findings are useful when differentiating between the types as well as in planning the management of these patients. Objectives: To make a report of a rare case of arteriovenous malformation of the uterus in a young female patient with a review of relevant literature as well as to highlight the importance of Colour Doppler ultrasonography in the evaluation of uterine lesions. Case Presentation: The case is of a 36year old female patient with a 2 years history of amenorrhoea following multiple sessions of dilatation and curettage. She also had chemotherapy due to choriocarcinoma. Pregnancy test was negative. Pelvic ultrasound scan done showed multiple cystic tubular spaces that were hypervascular on colour Doppler interrogation. High velocities and low RI values were recorded. Conclusion: Uterine arteriovenous malformations (AVMs) are important rare vascular disorders of the uterine vessels that need to be recognized early on imaging for appropriate management to be instituted.

Incompressible smoothed particle hydrodynamics solutions of double diffusion of nanoparticle-enhanced phase change materials in vertical mounted circular cylinders

The scheme of incompressible smoothed particle hydrodynamics (ISPH) method is developed to solve the time-conformable systems that control the double diffusion of nanoparticle-enhanced phase change materials (NEPCM) inside two circular cylinders saturated by a porous medium. The use of the time-conformable operator in the ISPH approach for addressing the double diffusion of NEPCM in a new domain is what distinguishes this work. This investigation revealed a comprehensive rate of change that impacts the quickening and slowdown of the monotonicity for the nonlinear systems. The physical parameters are time-conformable operator α , time parameter τ , nanoparticles parameter ϕ , Hartmann number Ha , thermal radiation parameter Rd , Darcy parameter Da , Rayleigh number Ra , and fusion temperature θ f . The principal outcomes of the numerical simulations revealed that the nanofluid flow is slowing down by an augmentation in ϕ , Ha , and Rd . The Rayleigh number is working well in enhancing the nanofluid flow and thermosolutal convection within the two circular cylinders. As a result, variable values of Ra are affecting the phase change material. The fusion temperature parameter controls the position/intensity of the phase change material within the two circular cylinders. Besides, the numerical results indicate the significance of α on the transition process of reaching the steady state. The thermosolutal convection and nanofluid speed are varied with the changes on the time-conformable derivative.

Heavy metals contamination and ecological risks in agricultural soils of Uşak, western Türkiye: a geostatistical and multivariate analysis.

This research aimed to determine and evaluate the concentrations ofAs, Cu, Hg, Ni, and Pb, and the physicochemical properties of 48 agricultural soil samples, to identify potential ecological risks and their sources associated with heavy metals contamination in Usak, western Türkiye. Various methods were used to assess ecological risks, including geoaccumulation index (Igeo), enrichment factor (EF), degree of contamination (Cdeg), potential ecological risk (RI), and pollution load index (PLI). The heavy metals concentrations ranged from 4 to 61mg/kg for As, 8-48mg/kg for Cu, 0.01-0.06mg/kg for Hg, 30-813mg/kg for Ni, and 4-30mg/kg for Pb. The mean As and Ni concentrations were much greater than Earth's crustal average, the world's mean values, and mean values from many other emerging countries. Igeo and EF values for As, Ni, and Pb indicate various degrees of contamination. Cdeg values show that 96% of the study area is affected to some degree by contamination. For RI values, 38% indicate ecological risks ranging from moderate to considerable degrees. PLI values show that 75% of the agricultural soils are moderately polluted. Spatial distribution maps of Cdeg, RI, and PLI show that the northeastern and southwestern parts of the study area have been polluted to different levels by As, Ni, and Pb. Industrial activities and excessive use of fertilizers, pesticides, fungicides, and herbicides were identified as major sources of heavy metals contamination in the agricultural soils of Uşak.

Parametric optimization to establish eco-friendly nanofluid minimum quantity lubrication (NMQL) practice for turning superalloy Inconel 718

Purpose The purpose of this paper, an experimental study, is to investigate the optimal machining parameters for turning of nickel-based superalloy Inconel 718 under eco-friendly nanofluid minimum quantity lubrication (NMQL) environment to minimize cutting tool flank wear (Vb) and machined surface roughness (Ra). Design/methodology/approach The central composite rotatable design approach under response surface methodology (RSM) is adopted to prepare a design of experiments plan for conducting turning experiments. Findings The optimum value of input turning parameters: cutting speed (A), feed rate (B) and depth of cut (C) is found as 79.88 m/min, 0.1 mm/rev and 0.2 mm, respectively, with optimal output response parameters: Vb = 138.633 µm and Ra = 0.462 µm at the desirability level of 0.766. Feed rate: B and cutting speed: A2 are the leading model variables affecting Vb, with a percentage contribution rate of 12.06% and 43.69%, respectively, while cutting speed: A and feed rate: B are the significant factors for Ra, having a percentage contribution of 38.25% and 18.03%, respectively. Results of validation experiments confirm that the error between RSM predicted and experimental observed values for Vb and Ra is 3.28% and 3.75%, respectively, which is less than 5%, thus validating that the formed RSM models have a high degree of conformity with the obtained experimental results. Practical implications The outcomes of this research can be used as a reference machining database for various metal cutting industries to establish eco-friendly NMQL practices during the turning of superalloy Inconel 718 to enhance cutting tool performance and machined surface integrity. Originality/value No study has been communicated till now on the turning of Inconel 718 under NMQL conditions using olive oil blended with multi-walled carbon nanotubes-based nanofluid. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2023-0317/