Wedge Angle Research Articles

The Relationship Between Different Body and Udder Shapes and Sizes with Milk Yield in Buffaloes

Several studies have been conducted with the objective of examining the potential relationship between different udder and body shapes and sizes and milk yield in buffaloes. In one study, it was stated that the relationship between milk yield and teat diameter was significant. In another study, conical and round teats were found to have the highest milk yield. Milk yield and udder width and lactation number were also positively correlated. It was found that there were some positive correlations between rear udder width, rear udder height, rear udder distance, udder length, front-rear teat distance; left rear teat length, left front teat length; right rear teat length and right front teat length. It was observed that body length was significantly associated with milk yield. While 1 cm increase in body length increased milk yield by 15.96 grams/day on average, each 1 cm increase in chest circumference increased milk yield by 17.96 grams/day. The highest milk yield was recorded at the height of the withers (145 cm) and at the depth of the chest (80 cm). A positive relationship was found between the distance between the hip bones and upper wedge angle and milk yield. Another study found that the thickness of the skin affects how much milk buffaloes produce. The thicker the skin in the flank and udder regions, the less milk the buffalo produces. The correlation coefficient in the flank region was -0.334 and in the udder region was -0.264.

Analysis of cutting forces and microdamage during indentation cutting of bone.

In surgery, bone can be cut by applying force to a wedge-shaped blade. The published literature is relatively sparse regarding the biomechanics of this type of indentation cutting, especially regarding the relationships between blade geometry, bone quality, cutting force and microdamage. Microdamage created near the cut surfaces can be beneficial, as a trigger for bone remodelling, but it is known that excessive fracture damage can prolong the healing time. In this research, specimens of compact bovine bone were tested by cutting using wedge blades of different geometries. We labelled and measured microdamage occurring during bone cutting for the first time. We found that there were statistically significant effects arising from the variation in wedge angle, edge radius and blade orientation (with respect to bone's anisotropic structure) on both the magnitude of the cutting force and the extent of the microdamage. Interestingly, we found that the amount of damage occurring during cutting is directly correlated to the cutting force which causes the damage, independent of other factors. This work contributes to a better understanding of the biomechanics of this important surgical cutting process.

Fracture Energy Determination of Wedge-opening Double Cantilever Beam Tests

ABSTRACT Adhesive fracture energy is often measured using the double cantilever beam (DCB) test method. However, opening a DCB specimen using a wedge differs the direction of the applied load from that of standard methods. The additional moment due to the longitudinal load alters the load-displacement-crack length relationship, requiring modifications in fracture energy calculation. The energy release rate (ERR) approach and the J-integral approach have been proposed to evaluate the fracture energy in wedge-opening DCB tests. However, these theories have limitations regarding wedge angles. In this study, we extended these theories to accommodate arbitrary wedge angles and performed numerical analyses to evaluate the accuracy of the theories. When the additional moment effect is neglected, the more obtuse the wedge angle and the thinner the adherend, the greater the error in the ERR. The error was over 5% when the wedge angle exceeded 90°. However, using the proposed ERR method, the error was reduced to less than 2% for all the wedge angles. When pin blocks were introduced into the DCB specimen, the additional moment effects increased the error to more than 5% even using the proposed ERR method. In this case, the modified J integral method yielded the lowest error results.

Twenty year outcomes following short-segment posterior instrumentation and fusion for thoracolumbar burst fractures: A retrospective observational study.

This study reviews the long-term efficacy of short-segment posterior instrumentation and fusion (SSPIF) in treating thoracolumbar burst fractures. Authors retrospectively reviewed the radiographic results of single-level thoracolumbar burst fractures treated by SSPIF. Vertebral body height and wedge angles were measured on the preoperative, postoperative, and follow-up radiographic images. The degree of pain and work ability was measured using the Denis scale. The analysis consisted of 12 patients with a mean age of 39.7 years (range 21-60) and a mean follow-up of 225.6 ± 20.3 months. There were significant differences among the wedge angles at preoperative and other periods of time, but there was no significant difference between the early postoperative and all other time periods afterwards (P < .001, P = .567, P = .937, P = .879). SSPIF effectively restored the anterior and middle vertebral body height and wedge angle deformities, and the improvement was maintained for almost 20 years after the surgery. Therefore, SSPIF is a safe and effective modality of treatment for thoracolumbar burst fractures.

Optimization and sensitivity analysis of magnetic fields on nanofluid flow on a wedge with machine learning techniques with joule heating, radiation and viscous dissipation

PurposeIn this study, the flow of nanofluids (NFDs), consisting of water and copper nanoparticles over a wedge, is simulated. The analysis considers the effects of a magnetic field (MFD) and Joule heating (JOH). Variables such as nanoparticle volume fraction (NVF), Eckert number (EC), radiation, and wedge angle (BT) are also examined for their impacts on the Nu and Cf. Design/methodology/approachThe simulation utilizes the similarity method and the Keller box method, implemented through custom coding. Additionally, machine learning techniques are applied for sensitivity analysis and optimization of the results by varying the parameters. FindingsThe findings indicate that increasing the BT, NVF and MFD strength can elevate the average friction coefficient (Cf-m) by up to 42.8 %. Sensitivity analysis reveals that factors like BT and MFD significantly influence the Cf-m and Nu. An increase in MFD strength generally reduces the Nu-m. A larger BT substantially boosts the Nu-m; however, heightened JOH results in a sharp decline in the Nu. An increase in the EC leads to a decrease in the Nu-m. At low radiation parameter (RD) values, increasing this parameter reduces the Nu-m, whereas at higher values, it increases the Nu. Originality/valueThe key contribution of the article is the optimization and sensitivity analysis of NFD flow over a surface, considering the effects of a MFD, JOH, radiation, EC, and BT. This is done to achieve maximum heat transfer and minimum friction loss.

Numerical study on flow and combustion properties of oblique detonation engine in a wide speed range

Ensuring safe flight is a fundamental prerequisite for developing hypersonic propulsion systems. A comprehensive investigation of the steady boundary associated with oblique detonation wave in a wide speed range was conducted, with the aim of exploring the feasibility of oblique detonation engine across a diverse array of flight conditions. In this study, the wedge angle applicable in a wide-speed range was acquired via the analysis of oblique detonation wave polar curve. The configuration of the internal injection oblique detonation engine was subsequently designed and established, considering the effect of fuel-air inhomogeneity and complex wave system interactions within a confined combustor. The compressible Euler equations coupled with a 9-species and 19-step chemical reaction mechanism are employed to simulate the oblique detonation process. Ultimately, the safe flight envelope of an air-breathing vehicle equipped with the internal injection oblique detonation engine is mapped across a broad range of Mach numbers, demonstrating the engine’s capability to operate within the Mach 8 to 12 range. Furthermore, the findings reveal that decreasing either the flight Mach number or altitude results in unsteady oblique detonation wave within the internal injection oblique detonation engine combustor, however, reducing the equivalence ratio can stabilize the oblique detonation wave once again. This study provides valuable guidance for the design and wide-speed-range operation of an internal injection oblique detonation engine.

Study on the characteristics of cavitation and COD removal of an addendum rotational hydrodynamic cavitation reactors

AbstractThis paper presented an addendum rotational hydrodynamic cavitation reactors (ARHCR) that enabled circumferential shear cavitation, axial cavitation, and the Venturi effect, thus increasing cavitation efficiency. The experiments on hydroxyl (·OH) release and chemical oxygen demand (COD) removal demonstrate the feasibility of cavitation performance characterization and COD removal rate. The findings indicate that the COD removal rate can reach a maximum value of 28% or 30% with an increase in flow rate or rotating speed, respectively. Specifically, the maximum values were achieved at a rotation speed of 2,500 rpm or a flow rate of 1.0 m3·h−1. Based on the mechanism of the addendum cavitation, the wedge angles, and the crucial structural parameters, were examined for optimizing cavitation performance. The results revealed that the cavitation number and cavitation bubble were significantly influenced by wedge angles, as well as the efficiency of cavitation energy. The mechanical shear of fluid was enhanced by wedge angles, resulting in constant compression and release of fluid with increased kinetic energy. This led to stronger effects on bulge blocks, and the formation of vortexes that rebounded constantly, resulting in lower pressure areas and expanded regions of cavitation. Among the wedge angles tested, the wedge angle of 15° exhibited the highest cavitation bubbles with a maximum value of 46%. This was 31% higher than the grooves‐type cavitator reported. Furthermore, the cavitation performance was extremely improved with a wedge angle of 15°, as corresponding with the maximum efficiency of cavitation energy. These explorations provide references for the removal of COD in industrial and agricultural wastewater, as well as the development of novel reactors for wastewater treatment.

Evaluation of Dose Calculation Algorithms Accuracy for ISOgray Treatment Planning System in Motorized Wedged Treatment Fields.

Different dose calculation methods vary in accuracy and speed. While most methods sacrifice precision for efficiency Monte Carlo (MC) simulation offers high accuracy but slower calculation. ISOgray treatment planning system (TPS) uses Clarkson, collapsed cone convolution (CCC), and fast Fourier transform (FFT) algorithms for dose distribution. This study's primary goal is to evaluate the dose calculation accuracy for ISOgray TPS algorithms in the presence of a wedge. This study evaluates the dose calculation algorithms using the ISOgray TPS in the context of radiation therapy. The authors compare ISOgray TPS algorithms on an Elekta Compact LINAC through MC simulations. The study compares MC simulations for open and wedge fields with ISOgray algorithms by using gamma index analysis for validation. The percentage depth dose results for all open and wedge fields showed a more than 98% pass rate for points. However, there were differences in the dose profile gamma index results. Open fields passed the gamma index analysis in the in-plane direction, but not all points passed in the cross-plane direction. Wedge fields passed in the cross-plane direction, but not all in the in-plane direction, except for the Clarkson algorithms. In all investigated algorithms, error increases in the penumbra areas, outside the field, and at cross-plane of open fields and in-plane direction of wedged fields. By increasing the wedge angle, the discrepancy between the TPS algorithms and MC simulations becomes more pronounced. This discrepancy is attributed to the increased presence of scattered photons and the variation in the delivered dose within the wedge field, consequently impacts the beam quality. While the CCC and FFT algorithms had better accuracy, the Clarkson algorithm, particularly at larger effective wedge angles, exhibited greater effectiveness than the two mentioned algorithms.

Is it safe to treat osteoporotic burst thoracolumbar fracture using percutaneous vertebroplasty? A minimum of 5-year follow-up study

BACKGROUND CONTEXTPercutaneous vertebroplasty for the treatment of osteoporotic burst fractures remains controversial. A previous study has shown that an osteoporotic burst fracture with asymptomatic spinal canal compromise is not a contraindication for percutaneous vertebroplasty. PURPOSETo determine whether these outcomes persist over a long term, we continued to observe patients in their short-term study over a long-term period. STUDY DESIGNProspective study. PATIENT SAMPLEPatients with osteoporotic vertebral fractures were classified as Dennis type I and II and AO type A1-A4, and no neurological deficits were observed. OUTCOME MEASURESOswestry disability index and visual analog scale (VAS11VAS, visual analogue scale.) for pain were outcome measures. Radiological outcomes were vertebral body height and kyphotic angle. Complications included cement leakage, adjacent fractures, and transition to instrumented fusion. METHODSBetween June 2015 and December 2016, 96 patients with osteoporotic vertebral fractures who met the inclusion criteria were prospectively enrolled. Preoperative, postoperative, and latest follow-up clinical outcomes were assessed using the Oswestry disability index and VAS. The radiological outcomes included vertebral body height, kyphotic angle, and adjacent fractures. Patients with intractable pain and neurological deficits during the follow-up were indicated for surgical treatment using decompression and instrumented fusion. RESULTSFifty-one patients with osteoporotic compression fractures and 45 with osteoporotic burst fractures were included in this study. Mean follow-up duration was 74 months, and posterior vertebral body height, kyphotic wedge angle, and VAS score were not altered during the follow-up period. Three (5.9%) patients in an osteoporotic compression fracture group and three (6.7%) in a osteoporotic burst fracture group developed persistent pain, further collapse, and neurological deficits, and were indicated for surgical treatment. No significant differences were observed in the rates of adjacent fractures. Percentage of patients who required surgical treatment was not significantly different between the groups. CONCLUSIONSOsteoporotic burst fractures with asymptomatic spinal canal compromise treated with percutaneous vertebroplasty are safe and effective for pain management during long-term follow-up.

Regular reflection to Mach reflection (RR–MR) transition in short wedges

Regular reflection (RR) to Mach reflection (MR) transitions ( ${\rm RR}\leftrightarrow {\rm MR}$ ) on long wedges in steady supersonic flows have been well studied and documented. However, in a short wedge where the wedge length is small, the transition prediction becomes really challenging owing to the interaction of the expansion fan emanating from the trailing edge of the wedge with the incident shock and the triple/reflection point. The extent of this interaction depends on the distance between the wedge trailing edge and the symmetry line (Ht). This distance is a geometric combination of the distance of the wedge leading edge from the symmetry line $(H)$ , the wedge angle ( $\theta$ ) and the wedge length $(w)$ . In the present study, we used the method of characteristics to model the complete wave interactions which accurately predicted shock curvatures and the reflection configurations for all ranges of the incoming flow Mach number. In the case of short wedges, the transition criterion strongly depends on the wedge length, which can be so adjusted even to eliminate the ${\rm RR}\rightarrow {\rm MR}$ transitions till the wedge angle reaches the no-reflection domain. Transition lines for both the detachment criterion and von Neumann criterion are also drawn to investigate the dual solution domain, and the reflection configurations were verified experimentally for the first time on short wedges. By using proper input configuration parameter ( $w/H$ ), various types of shifts in the dual solution domain for short wedges are studied and categorised into three types, namely Type I, Type II and Type III.

Tool–Branch Interaction Mechanism of Impact-Pruning Process Based on Finite Element Method

This study addresses the necessity for a more profound comprehension of the mechanical behavior and fracture mechanisms of tree branches during impact pruning. The methodologies of the research are to develop a failure model of impact-cutting mechanics and a tool–branch interaction model using the finite element method (FEM). The validation of the model was conducted through the measurement of cutting forces and cross-sectional morphology in the field. A comparative analysis between experimental and simulation data revealed an average relative error below 15% for cutting force and below 10% for the cross-sectional ratio, thereby confirming the accuracy of the model. The findings indicate the presence of plastic deformation within the cutting zone, with elastic deformation prevailing in the surrounding region. As the branch approaches the yield point, the phenomenon of plastic deformation intensifies, resulting in a notable increase in internal energy demands, particularly in larger branches. The optimal pruning diameter was identified as 15 mm. An increase in cutting velocity raises the peak cutting force by 460.9 N per m/s, while a 1° increase in the blade wedge angle adds 34.9 N. A reduction in normal stress by increasing the tool back angle improves energy efficiency. This study provides insights to optimize pruning practices, enhancing efficiency and precision.

Thermal transportation of radiative cathode nanotube‐based nanofluid on a stretching/shrinking wedge with varying magnetism and heat source

AbstractThe complex heat transfer processes occurring in a magnetized water‐based hybrid nanofluid flowing past a stretching or shrinking wedge are investigated in this work. The research highlights the significant influence of the wedge angle on fluid flow patterns and temperature gradients, emphasizing how larger angles cause changes in pressure, flow separation, and temperature profiles. Additionally, the study emphasizes the importance of radiation effects near surfaces, where increased radiation often leads to cooling due to thermal energy emission. The findings have implications in industries such as aerospace, electronics, thermal management, and groundwater resources management where precise temperature control is critical for safe and efficient operations. The numerical method applied to solve the governing equations in the study is the fourth‐order Runge–Kutta technique with shooting technique. This method efficiently solves the boundary value problem by converting it into a system of first‐order initial value problems. Then shooting technique is used to solve the system, starting with an adequate initial guess. The study's results are presented in tabular and graphical forms, providing valuable insights into the complex fluid dynamics and thermal behavior in the given setting, enabling more informed decision‐making and optimization in relevant engineering applications. Increased radiation frequently results in a cooling effect owing to thermal energy output. Heat sinks/heat sources are crucial in temperature regulation and are effective in lowering temperatures via processes. We also emphasize the importance of radiation impacts near surfaces, where increased radiation frequently leads to cooling owing to thermal energy emission. The numerical values of skin friction and Nusselt number for various parameters in the cases of shrinking and stretching provide crucial insights into the heat transmission and frictional properties of the system under examination. These quantitative results contribute to a better understanding of the complex fluid dynamics and thermal behavior in the given setting, emphasizing the significance of the research findings.

Error analysis based on a tunable wave plate polarization interferometric imaging spectrometer

Interference imaging spectroscopy combines modern imaging technology with spectral technology, holding significant importance for object imaging and spectral detection. This article introduces the principle of an adjustable wave plate polarization interferometric imaging spectrometer. The example design specifications are set for an observation wavelength range of 450–780 nm and a maximum resolution of 2 nm at 450 nm, with a 0.5 in detector as the base for calculating the specific dimensions of the Soleil–Babinet compensator. An investigation was conducted on the issues of nonuniform sampling, as well as three types of mechanical errors: flatness, wedge angle tolerance, and optical axis orientation accuracy. Emphasis was placed on discussing the impact of these errors on the instrument’s optical path difference and spectral reconstruction accuracy. This research provides theoretical guidance for the design and engineering of this miniaturized imaging spectrometer.

Effect of screw insertion depth into fractured vertebrae in the treatment of thoracolumbar fractures

PurposeThe study’s objective was to assess the effect of the screw insertion depth into fractured vertebrae in treating thoracolumbar fractures.Materials and methodsThis was a retrospective analysis of 92 patients with thoracolumbar fractures from December 2018 to February 2020. Patients had AO type A2, A3 thoracolumbar fractures. The patients were divided into two groups according to the screw insertion depth. The vertebral wedge angle (VWA), Cobb angle (CA), anterior vertebral body height (AVBH), middle vertebral body height (MVBH), visual analog scale (VAS) score, and Oswestry Disability Index (ODI) were compared preoperatively and at one week and 12 months postoperatively. The correlation between Vertebral height loss and potential risk factors, such as sex, age, BMD and BMI was evaluated.ResultsCompared with the preoperative data, the postoperative clinical and radiographic findings were significantly different in both groups, But no significant difference between the two groups at 1 week. At 1 year postoperatively, there was a significant difference in the CA (p < 0.0001), VWA (p = 0.047), AVBH (p < 0.0001), MVBH (p < 0.0001), VAS score (p < 0.0001), and ODI (p < 0.0001) between the two groups, Except for age, bone density and other influencing factors the long screw group had better treatment results than the short screw group.ConclusionA longer screw provides greater grip on the fractured vertebral body and stronger support to the vertebral plate. The optimal screw placement depth exceeds 60% of the vertebral body length on the lateral view.

Overloaded Vertebral Body Following Consecutive Three-Level Hybrid Surgery Comparing with Anterior Cervical Discectomy and Fusion.

Based on the varying number and relative positions of cervical disc replacement (CDR) and anterior cervical discectomy and fusion (ACDF) procedures, three-segment hybrid surgery (HS) presents a diverse structural approach. Currently, the potential differential effects of HS with different segment combinations and surgical procedures on overloaded vertebral body (OVB) occurrence remain unexplored. The purpose of this retrospective study is to compare the clinical and radiological outcomes of HS and ACDF in treating cervical degenerative disc disease (CDDD), aiming to provide further insights into OVB. This study included patients with three-level CDDD who underwent ACDF or HS at our institution. Eligible patients were divided into three groups: Type I (one-level CDR and two-level ACDF), Type II (two-level CDR and one-level ACDF), and ACDF (three-level ACDF). For radiographic analysis, patients were further divided into the Replacement Segment Group and the Nonreplacement Segment Group based on the presence of replacement segments above and below the OVB. Clinical outcomes were evaluated using visual analog scale (VAS) scores for neck and arm pain, Japanese Orthopedic Association (JOA) scores, and neck disability index (NDI) scores. The cervical radiological parameters assessed included (1) vertebral cross-sectional area (CSA), (2) wedge angle (WA), (3) anterior vertebral height (AH), (4) posterior vertebral height (PH), and (5) Hounsfield unit (HU) values. Statistical methods included paired t-test, ANOVA test, and chi-square test. Independent samples t-test, Mann-Whitney U test, and Wilcoxon signed-rank test were used to compare the differences between two groups according to the results of normal distribution test. A total of 123 patients, evenly distributed among three groups, were included and were well matched in terms of demographic characteristics. The likelihood of vertebral body collapse (VBC) was notably higher in the ACDF group (41.5%) compared with the Type I (17.9%) and Type II (8.9%) groups (p < 0.01). Following surgery, both at 3 and 6 months, the ACDF group demonstrated higher VAS neck scores and NDI scores compared with the Type I and Type II groups (p < 0.01). Additionally, the WA and AH values of the upper and lower adjacent OVB were consistently lower in the ACDF group than in the Type I and Type II groups at 6 and 12 months and at the final follow-up (p < 0.01). Notably, in the Nonreplacement Segment Group, WA significantly decreased at 12 months postoperatively and at the final follow-up compared with the Replacement Segment Group (p < 0.01). Three levels of HS appear to reduce stress concentrations and alleviate morphological changes in OVB. The occurrence of more VBC patients with OVB was associated with the use of Zero-P or Zero-P VA implants.

Ultrasonography-guided canal decompression combined with vertebroplasty and cement-augmented pedicle screw fixation for stage III Kümmell’s disease with neurological deficits: a retrospective cohort study

BackgroundPercutaneous vertebroplasty or kyphoplasty is the preferred procedure for stage I and II Kümmell’s diseases (KDs), but there exist controversies on the operative option of stage III KD. This study aimed at exploring the safety and efficacy of ultrasonography-guided canal decompression (UG-CD) combined with vertebroplasty and cement-augmented pedicle screw fixation (CA-PSF) for treating stage III KD with neurological deficit (ND).MethodsBetween September 2017 and December 2023, all patients who received the UG-CD combined with vertebroplasty and CA-PSF for managing stage III KD with NDs were reviewed retrospectively with their demographic and operation data, and complications recorded. Besides, the scores of Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI), together with imaging data including the kyphotic Cobb angle (KCA), wedge angle (WA), spinal canal area (SCA) at the narrowest level as well as anterior (AHR) and middle (MHR) height ratios were measured and compared between pre- and post-operation.ResultsA total of eleven patients with a mean age of 70.09 ± 2.98 years old were included in our study with their surgical time, hospitalization length, blood loss, and follow-up time being 150.91 ± 17.94 min, 202.09 ± 39.95 ml, 8.18 ± 1.17 days, and 16.91 ± 4.09 months, respectively. During the final follow-up, the KCA, WA, VAS scores, ODI scores, AHR, MHR, and SCA were significantly improved (P < 0.01). Intraoperatively, one case suffered a transient decrease in the motor evoked potential. Another case experienced a cerebrospinal fluid leakage postoperatively that was then successfully treated.ConclusionUG-CD combined with vertebroplasty and CA-PSF could be a feasible procedure for safely and effectively handling stage III KD with NDs.

Bone density as a risk of early loss of correction after percutaneous posterior spinal fixation for traumatic thoracolumbar fracture: a study on the usefulness of Hounsfield unit values on computed tomography scan.

Vertebral Hounsfield unit values on computed tomography scan (CT values) have been found to be correlated with bone density measured using dual-energy X-ray absorptiometry. We hypothesized that low preoperative CT values are risk factors for early loss of correction after percutaneous posterior spinal fixation (PPSF). This study aimed to evaluate the usefulness of measuring preoperative CT values. In total, 104 patients underwent PPSF due to traumatic thoracolumbar fracture. Among them, 53 with a range of fixation that was within two vertebrae above and below the fractured vertebra were selected. CT values were measured preoperatively from the most cephalad vertebrae on the fixed vertebrae. Vertebral wedge angle (VWA) and local kyphosis angle (LKA) were measured before and after surgery. participants were classified into progression (P) and nonprogression (NP) groups. The P group comprised patients with LKA progressing > 10° from the immediate postoperative period to 3months postoperatively. Meanwhile, the NP group included patients without progression. Eight (15.1%) patients were included in the P group. The vertebral CT values were 102.2 ± 36.7 in the P group and 162.4 ± 59.7 in the NP group (p < 0.01). The pedicle CT values were 114.4 ± 45.9 in the P group and 170.8 ± 72.3 in the NP group (p < 0.05). At 2weeks postoperatively, VWA and LKA of the P group progressed to 9.8° ± 7.0° and 10.9° ± 7.6°, respectively. CT values can predict progressive loss of correction after PPSF.

Formation of property gradient in coarse-grained niobium using a wedge tool: Experiment and analysis

We introduce a novel severe plastic deformation process for coarse-grained niobium, which employs a tool with an inclined (wedge) surface for deforming the material by a reverse shear scheme. The process increases the intensity of shear deformations and the depth of plastic deformation in the body of the workpiece when a wedge tool acts on its surface. The essence of the process is in the repeated displacement of the workpiece material in opposite directions during the asymmetrical introduction of a wedge tool until the required degree of deformation is accumulated in the tool-affected volume. This deformation scheme applies a 15° angle wedge tool to a 21-mm high workpiece. After nine cycles of plastic deformation, a gradient of the accumulated degree of deformation in the range of true strain e = 0.3–4.5 was created. At maximum deformation, the microhardness of the workpieces increased by 1.86 times and the tensile strength by 1.6 times. Fractograms show a significant influence of the accumulated degree of deformation on the nature of the fracture. The finite element method simulation of the deformation process showed that creating a uniformly strengthened layer requires at least five deforming operations. For example, the proposed reverse shear process with a wedge tool can be applied to improve the structure of the surface layers of niobium ingots for subsequent forming. Due to the creation of a significant gradient of properties, the reverse shear process can be used as an express method for determining the mechanical characteristics of different materials in a wide range of accumulated degree of deformation.

Analysis of Wedge Angle Variations in the Treatment Planning System Based on Dose Volume Histogram on Ca Mammae Sinistra

Breast cancer ranks first in terms of the highest number of cancers in Indonesia and is one of the first contributors to cancer deaths. According to IARC, radiotherapy is one of the most important modalities in the treatment of breast cancer. Radiotherapy is a type of treatment that uses ionizing radiation to kill cancer cells without damaging surrounding healthy tissue. To obtain an even or homogeneous dose distribution on an uneven skin surface, a wedge is used so that the radiation given to the tumor area is truly optimal and the surrounding healthy tissue receives a minimum dose. This research was carried out by evaluating the Planning Target Volume (PTV) value based on ICRU-83 and dose distribution in Organs at Risk (OAR) based on QUANTEC standards at four different wedge angles, namely 15°, 30°, 45°, and 60°, used the 3D-CRT technique of tangential radiation with a dose of 50 Gy in 25 fractions on 5 left-sided breast cancer patients. The research results showed that the average Homogeneity Index (HI) values for the 15°, 30°, 45° and 60° wedges were 0.286, 0.346, 0.436 and 0.578, respectively. In the left and right lung dose distribution, the results obtained for the 15°, 30°, 45°, and 60° wedge were respectively 2231.4 and 116.2 cGy, 2257.8 and 114.6 cGy, 2141 and 100 cGy, and 2059.4 and 88.8 cGy. For the average dose distribution to the heart, the values obtained at the 15°, 30°, 45°, and 60° wedges were 2005.6 cGy, 2040.4 cGy, 1930.6 cGy, and 1844.4 cGy, respectively. where the average dose received by OAR is still below the limit allowed by QUANTEC. Using a wedge angle of 15° provides a homogeneous dose distribution for the PTV and a wedge angle of 60° provides the lowest dose distribution for the OAR.

Significances of melting heat transfer and bioconvection phenomena in nanofluid flow over a three different geometries

This study addresses the numerical investigation of the steady and two-dimensional flow of magnetohydrodynamic nanofluid containing motile microorganisms over three distinct configurations: a wedge, a plate, and the stagnation point of a flat plate. The impacts of activation energy, melting phenomena, thermophoresis, and Brownian motion are taken into account. The dimensionless form of the governing coupled nonlinear partial differential equations is obtained by using similarity transformations. The system of ordinary differential equations is numerically solved using the “bvp4c” solver in MATLAB, and obtained results are also validated with an analytical approach Optimal Auxiliary Function Method (OAFM). Skin friction, heat, mass and motile microorganisms transfer rates are discussed through graphs and tables. Findings indicate that profile for Nusselt number enhances for higher inputs of melting parameter while Sherwood number lowers with increasing inputs of activation energy parameter. An improving pattern of velocity profiles is magnificent for stagnation point flow [f(η = 1) = 0.943711] compared to wedge [f(η = 1) = 0.915698]and horizontal plate [f(η = 1) = 0.868617]with respect to wedge angle parameter keeping velocity ratio parameter A < 1. For the wedge surface, the temperature profiles decrease [θ(η = 1.5) = 0.933075, 0.895245, 0.858931] for increasing inputs of radiation parameter (2.5 ≤ Nr ≤ 4.5) while motile microorganism profiles enhance [χ(η = 1.3) = 0.532505, 0.621569, 0.690635] with bioconvection Schmidtt number (0.3 ≤ Sb ≤ 0.7) respectively. Furthermore, it was found that, as velocity slip parameter increases then velocity of fluid also improves over a plate, wedge, and stagnation point of a flat plate considering velocity ratio parameter A < 1 .