Timing of Radiotherapy (RT) After Radical Prostatectomy (RP): Long-term outcomes in the RADICALS-RT trial [NCT00541047].

BACKGROUND: The optimal timing of radiotherapy (RT) after radical prostatectomy for prostate cancer has been uncertain. RADICALS-RT compared efficacy and safety of adjuvant RT versus an observation policy with salvage RT for PSA failure. METHODS: RADICALS-RT was a randomised controlled trial enrolling patients with ≥1 risk factor (pT3/4, Gleason 7-10, positive margins, pre-op PSA≥10ng/ml) for recurrence after radical prostatectomy. Patients were randomised 1:1 to adjuvant RT ("Adjuvant-RT") or an observation policy with salvage RT for PSA failure ("Salvage-RT") defined as PSA≥0.1ng/ml or 3 consecutive rises. Stratification factors were Gleason score, margin status, planned RT schedule (52.5Gy/20 fractions or 66Gy/33 fractions) and treatment centre. The primary outcome measure was freedom-from-distant metastasis, designed with 80% power to detect an improvement from 90% with Salvage-RT (control) to 95% at 10yr with Adjuvant-RT. Secondary outcome measures were bPFS, freedom-from-non-protocol hormone therapy, safety and patient-reported outcomes. Standard survival analysis methods were used; HR<1 favours Adjuvant-RT. FINDINGS: Between Oct-2007 and Dec-2016, 1396 participants from UK, Denmark, Canada and Ireland were randomised: 699 Salvage-RT, 697 Adjuvant-RT. Allocated groups were balanced with median age 65yr. 93% (649/697) Adjuvant-RT reported RT within 6m after randomisation; 39% (270/699) Salvage-RT reported RT during follow-up. Median follow-up was 7.8 years. With 80 distant metastasis events, 10yr FFDM was 93% for Adjuvant-RT and 90% for Salvage-RT: HR=0.68 (95%CI 0·43-1·07, p=0·095). Of 109 deaths, 17 were due to prostate cancer. Overall survival was not improved (HR=0.980, 95%CI 0.667-1.440, p=0.917). Adjuvant-RT reported worse urinary and faecal incontinence one year after randomisation (p=0.001); faecal incontinence remained significant after ten years (p=0.017). INTERPRETATION: Long-term results from RADICALS-RT confirm adjuvant RT after radical prostatectomy increases the risk of urinary and bowel morbidity, but does not meaningfully improve disease control. An observation policy with salvage RT for PSA failure should be the current standard after radical prostatectomy.

Short and Long-Term Clinical Outcomes in Octogenarian Patients With Non-ST-Elevation Myocardial Infarction: A Comparative Analysis of Revascularization Strategies Versus Medical Management.

INTRODUCTION: As the primary cause of morbidity and mortality among older individuals, cardiovascular disease remains a major concern. Choosing between revascularization and medical management of elderly patients remains controversial. This study aims to evaluate the clinical implications of these treatment approaches in the context of non-ST-elevation myocardial infarction (NSTEMI) in octogenarian patients. METHODS: This observational cohort study involved 41 octogenarian patients who were diagnosed with NSTEMI from 2019 to 2021 and were managed by revascularization (with either percutaneous coronary intervention, coronary artery bypass graft surgery, or both) or conservative medical therapy. All NSTEMI patients were diagnosed based on symptoms, electrocardiographic changes, and cardiac biomarkers. The study compared the short- and long-term outcomes of 13 patients in the revascularization group and 28 in the medical therapy group. RESULTS: Overall, the mean patient age was 84.63 years. Eighteen patients were men (43.9%), and 23 were women (56.1%). The most prevalent disease among the sample was hypertension (34 patients, 82.9%), followed by diabetes mellitus (27 patients, 65.9%) and prior ischemic heart disease (21 patients, 51.2%). Almost all patients in the revascularization-treated group developed complications after the procedure (84.6%), while 46.4% of the patients in the medication-only group developed a complication later on. The revascularization-treated group showed higher mortality rates in both the short- and long-term (23.1% and 38.5%, respectively) compared to the medication-only group, which showed better survival rates numerically in both the short- and long-term (14.3% and 32.1%, respectively). This was not statistically significant. CONCLUSION: Revascularization treatment in elderly patients with NSTEMI was associated with a higher risk of complications and a higher mortality rate compared with conservative medical management. Patients managed with only medications had a better survival rate in both the short- and long-term.

Retraction: Unicentric Castleman Disease With Systemic Symptoms: A Rare Case From Family Practice.

[This retracts the article DOI: 10.7759/cureus.21132.].

MPPT control of a solar pumping system based five-phase impedance source inverter fed induction motor.

This paper presents a control method for a system composed of a photovoltaic (PV) array, five-phase impedance source inverter, five-phase induction motor and centrifugal pump. This method is based on controlling the motor speed to control the pump power as the insolation level or temperature change to attain the maximum power extraction from the PV-array. The motor speed is controlled by using artificial neural network (ANN) which is trained to provide the desired inverter frequency and modulation index at any insolation level and temperature to attain the maximum PV operating power. The data of the neural network are based on the operation of the induction motor at constant air gap flux and perturb and observe method for maximum power point tracking. Simulation results are obtained using MATLAB Simulink to verify the proposed control method.

Review of speed estimation algorithms for three- phase induction motor.

In the field of evolving industrial automation, there is a growing need for refined sensorless speed estimation techniques for induction drives to cater the demands of various applications. In this paper, the sensorless speed estimation algorithms for induction motor drives are investigated and reviewed detailly for real-time industrial usages. The main objective of this paper is to classify sensorless techniques by highlighting the characteristics, merits and drawbacks of each sensorless speed estimation techniques of induction motor drives. Different techniques like Rotor slot harmonics, Signal Injection, and Machine model based system have the benefits of sensorless motor drives involving lower costs, higher reliability, simpler hardware complication, improved noise immunity, and lesser maintenance requirement. As a result of the advancement of current industrial automation, more improved sensorless estimation techniques are required to meet application demand. The various speed estimation techniques are distinguished based on criteria of steady state error, dynamic behavior, low speed operation, parameter sensitivity, noise sensitivity, complexity and computation time. This comparison allows to opt the best sensorless speed estimation technique for induction motor drive to be implemented based on a specific application. The results of comparison highlight the characteristics of each technique.

Analysis of active surveillance uptake for localized prostate cancer in Quebec in 2016: A Canadian bicentric study and comparison with 2010 data.

INTRODUCTION: Active surveillance (AS) has emerged as a primary management strategy for low-risk prostate cancer (PC) patients. We aimed to assess AS uptake over a 1-year snapshot throughout Quebec and to compare it to 2010 multicentric Canadian data. METHODS: A retrospective chart review and data collection was performed in 1 academic and 2 non-academic community centres from Quebec, among men identified in 2016 with localized T1c-T2c PC on biopsy, fulfilling NCCN criteria of low-risk (LR)-PC, including very-low-risk (VLR) and non-VLR-PC, and favourable-intermediate risk (FIR)-PC. AS adherence was defined when chosen as initial strategy, without any radical treatment within 6 months. RESULTS: Overall, 259 patients fulfilled the inclusion criteria with 50.2% of VLR-PC patients. At 6 months, 81% patients in the LR group and 65% in the FIR group were considered as adherent to AS, in both centres, but with an increased use of AS in the community centres compared to 2010 data. The rates of AS maintenance decreased at 12 months to respectively 69% and 58%. Among the VLR group, the rate of initiation was 98% and decreased to 85% at 12 months. CONCLUSION: Our data suggest that the majority of low-risk PC patients indeed initiated an AS in 2016, with even a greater proportion of VLR-PC patients compared to 2010. This ideal strategy should be encouraged and improved at 12 months, and assessed with recent data and longer follow-up.

Approximation of electrical double-layer thickness in hydrocarbon systems flowing through the pores of reservoir rocks.

In porous systems, such as in oil reservoir rock formations, the double layers from opposite sides of the pores may overlap if the pore size is narrow. This overlap is relatively likely to occur under low-electrolyte concentrations, such as those in crude oil, thus markedly affecting the electrokinetic measurements. This article evaluates the effects of overlap of the diffuse layers in the narrow capillaries of the reservoir rock cores in oils. Methods were developed to estimate the double-layer thickness in hydrocarbon systems, and to predict the effects of double-layer overlap on the streaming current and hence on the calculation of surface potentials for flat-sided capillaries. These methods are used to interpret results from sandstone cores in crude oil and hydrocarbon solvents. The estimation of double-layer thickness in non-aqueous solvents on the basis of 1:1 charge carriers by analogy to water systems, with correction for viscosity and permittivity differences provides good results with respect to those from streaming current measurements.

Early Surgical Reconstruction Versus Rehabilitation for Patients With Anterior Cruciate Ligament Rupture: A Systematic Review and Meta-Analysis.

Anterior cruciate ligament (ACL) rupture is a common and debilitating knee injury that can significantly impair knee function and stability. The optimal management of ACL injuries remains a topic of ongoing debate, with two primary treatment approaches being surgical reconstruction and adequate rehabilitation. The aim of this study is to compare the knee function and stability outcomes between these two treatment modalities, shedding light on their respective effectiveness. We utilized Scopus, PubMed, Cochrane Database, MEDLINE, and Web of Science from inception until April 20, 2022. We utilized the Cochrane risk of bias tool for quality assessment. The following outcomes were assessed: Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) Subjective Knee score, Lysholm score, the occurrence of the knee giving way, Tegner score, KT1000, Lachman test, pivot shift test, SF-36 score to assess the quality of life, and incidence of reinjury and reoperation. We included a total of six trials with a population sample size of 691 patients, which were divided into surgical versus non-surgical groups, accounting for 348 and 343 patients, respectively. The pooled estimate demonstrated that the surgical reconstruction was associated with a significant increase in the IKDC score (MD = 7.49 [2.04, 12.94], (P = 0.007)), and KOOS score was significant in the reconstruction cohort (MD = 5.87 [1.64, 10.09], (P = 0.007)). The incidences of reoperation (RR = 0.43 [0.20, 0.91], (P = 0.03)), reinjury (RR = 0.49 [0.27, 0.88], (P = 0.02)), and occurrence of the knee giving way (RR = 0.19 [0.08, 0.49], (P = 0.005)) were significantly decreased in the surgical cohort. There is no significant difference between both cohorts regarding the Lysholm score (1.27 [-1.39, 3.93], (P = 0.35)). The findings of this comprehensive analysis indicate that early reconstruction does not demonstrate clear superiority over rehabilitation alone in terms of knee function, Lysholm score, and Tegner score among patients with ACL rupture. However, early reconstruction does exhibit a substantial reduction in the incidence of reinjury, reoperation, and knee giving way, suggesting potential benefits in terms of stability outcomes. These results underscore the importance of considering individual patient characteristics and preferences in treatment decision-making.

Asphaltene Remediation and Improved Oil Recovery by Advanced Solvent Deasphalting Technology.

Resin molecules play a crucial role in the stability of colloidal asphaltene particles in petroleum reservoirs. De-stabilization of the asphaltene/resin interaction due to changes in thermodynamic parameters can cause asphaltene precipitation, thus leading to petroleum field problems such as decreased in situ permeability, as well as severe plugging problems in production facilities. One remedial technology used in the oil industry involves developing synthetic resins with enhanced chemical potential to increase the stability of asphaltene in the oil phase. However, accurately predicting what synthetic resin structures are compatible with asphaltenes in this context can be difficult and ineffective. Here, we introduce a method that enhances the stability of colloidal asphaltene in petroleum fluid by increasing the concentrations of natural-state oil resins and increases reservoir oil recovery by increasing the oil's aromatic power solvency. The stability of colloidal asphaltene and improvements in oil reservoir recovery were investigated by using an oil prefractionation process and a solvent deasphalting technology based on the residuum oil supercritical extraction process to develop three types of deasphalted oils derived from Kuwait Marrat oil. Using these methods, we found that resin concentration by volume in Marrat oil increased with the removal of more oil fractions. Asphaltene stability in the oil phase was strongly influenced by resin concentration. The deasphalted oils' aromatic power solvency increased the oil reservoir permeability by twofold. No formation damage was observed for all DAO products in core flooding tests.

Pyrolysis of Mixed Date Stones and Pistachio Shells: Identification of Bio-Oil and Utilization of Bio-Char as Activated Carbon Precursor.

Thermal pyrolysis of mixed date stones and pistachio shells in a semi-batch reactor was addressed in this study. The highest yield of liquids (51.20 %) was produced at 500 °C, 90 min, 20 °C/min heating rate, and 50 mesh particle size. Under these conditions, yield of liquid from date stones and pistachio shells separately was 49.12 % and 47.67 %, respectively. The FT-IR results confirmed the presence of multiple oxygen-containing compounds in the bio-oil. Results from GC-MS declared that it was predominately composed of acids (57.57 %), esters (21.35 %), phenols (4.63 5), and alcohols (3.49 5). The obtained biochar was transformed into activated carbon (AC) by the optimized ZnCl2 activation method. The ideal AC was synthesized at 600 °C for 60 min using a 2 : 1 ZnCl2 : biochar impregnation ratio. FESEM and XRD measurements showed that the AC was amorphous. The prepared AC was effective in eliminating dibenzothiophene (DBT) from model fuel (200 ppm DBT/hexane) with a maximum performance 95.26 % at 40 °C for 1h using 0.35 g of the AC. The exhausted AC was regenerated and reutilized 4 times, and removal efficiency reached 88.23 % in the 4th cycle under ideal working conditions.

Interfacial Adsorption Kinetics of Methane in Microporous Kerogen.

Rapid declines in unconventional shale production arise from the poorly understood interplay between gas transport and adsorption processes in microporous organic rock. Here, we use high-fidelity molecular dynamics (MD) simulations to resolve the time-varying adsorption of methane gas in realistic organic rock samples, known as kerogen. The kerogen samples derive from various geological shale fields with porosities ranging between 20% and 50%. We propose a kinetics sorption model based on a generalized solution of diffusive transport inside a nanopore to describe the adsorption kinetics in kerogen, which gives excellent fits with all our MD results, and we demonstrate it scales with the square of the length of kerogen. The MD adsorption time constants for all samples are compared with a simplified theoretical model, which we derive from the Langmuir isotherm for adsorption capacitance and the free-volume theory for steady, highly confined bulk transport. While the agreement with the MD results is qualitatively very good, it reveals that, in the limit of low porosity, the diffusive transport term dominates the characteristic time scale of adsorption, while the adsorption capacitance becomes important for higher pressures. This work provides the first data set for adsorption kinetics of methane in kerogen, a validated model to accurately describe this process, and a qualitative model that links adsorption capacitance and transport with the adsorption kinetics. Furthermore, this work paves the way to upscale interfacial adsorption processes to the next scale of gas transport simulations in mesopores and macropores of shale reservoirs.

Trial Participation is Not Associated with Better Biochemical Recurrence-free Survival in a Large Cohort of External Beam Radiotherapy-Treated Intermediate- and High-Risk Prostate Cancer Patients.

AIMS: There is a widespread belief that outcomes of cancer patients treated within clinical trials might not be representative of the outcomes obtained within standard clinical settings. We sought to investigate the effect of trial participation on biochemical recurrence (BCR) in localised, D'Amico intermediate- and high-risk prostate cancer patients treated with external beam radiotherapy (EBRT). MATERIALS AND METHODS: We relied on a study population treated with EBRT between January 2001 and January 2021 at a single tertiary care centre, stratified according to trial enrolment. Separate Kaplan-Meier and multivariable Cox regression models tested BCR-free survival at 60 months within intermediate- and high-risk EBRT patients, after adjustment for covariables. Additionally, the analyses were refitted after inverse probability treatment weighting was performed separately for both risk subgroups. RESULTS: Of 932 eligible patients, 635 (68%) and 297 (32%) had intermediate- and high-risk prostate cancer, respectively. Overall, 53% of patients were trial participants. BCR rates were 11 versus 5% (P = 0.27) and 12 versus 14% (P = 0.08) in trial participants versus non-participants for intermediate- and high-risk subgroups, respectively. Differences in patient and clinical characteristics were recorded. Trial participation status failed to reach predictor status in multivariable Cox regression models for BCR in both intermediate-risk (hazard ratio 1.34; 95% confidence interval 0.71-2.49; P = 0.4) and high-risk patients (hazard ratio 1.03; 95% confidence interval 0.45-2.34; P = 0.9). Virtually the same results were recorded in inverse probability treatment weighting cohorts. CONCLUSIONS: Relying on a large cohort of EBRT-treated intermediate- and high-risk patients, no BCR differences were recorded between trial participants and non-participants after accounting for confounders.

A Zintl Cluster for Transition Metal-Free Catalysis: C═O Bond Reductions.

The first fully characterized boron-functionalized heptaphosphide Zintl cluster, [(BBN)P7]2- ([1]2-), is synthesized by dehydrocoupling [HP7]2-. Dehydrocoupling is a previously unprecedented reaction pathway to functionalize Zintl clusters. [Na(18-c-6)]2[1] was employed as a transition metal-free catalyst for the hydroboration of aldehydes and ketones. Moreover, the greenhouse gas carbon dioxide (CO2) was efficiently and selectively reduced to methoxyborane. This work represents the first examples of Zintl catalysis where the transformation is transition metal-free and where the cluster is noninnocent.

Effects of Omega-3 Polyunsaturated Fatty Acids on Brain Functions: A Systematic Review.

Omega is a polyunsaturated fatty acid (PUFA) that has an essential impact on cognitive performance at all stages of life. Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA) are essential for brain functions. DHA, the dominant omega-3 in the brain, impacts neurotransmitters and functions of the brain. This systematic review aimed to assess the effects of omega-3 on brain functions. We searched for articles from 2010 to 2022 in PubMed, electronic databases: discover, academic search complete (EBSCO), and Cochrane. To increase search efficiency, search terms include database-specific indexed phrases and keywords. Search terms included "omega three," "DHA," "fish oil," "eicosapentaenoic acid," "EPA," "docosahexaenoic acid," "omega-3," "cognition," "brain," "mental health," and "PUFAs".We conducted a review of only randomized clinical trials (RCTs) that were published in English. We evaluated the quality of the studies using the Cochrane Collaboration bias assessment tool. Our search strategy yielded 174 articles, out of which 33 full-text articles were reviewed and nine articles were selected for data abstraction. The overall number of individuals in all nine studies was 1319. Of the participants, 591 (44.81%) were men, and 728 (55.19%) were women. Participants who received omega-3 were 700 (65.06%) compared to 376 (34.94%) who received a placebo, and their mean age was 45. Ingestion of omega-3 fatty acids increases learning, memory, cognitive well-being, and blood flow in the brain. Omega-3 treatments are advantageous, well-tolerated, and risk-free. Lonelier people, the elderly, and those who eat fewer healthy foods containing omega-3 may benefit from an omega-3 supplement. We suggest that natural omega-3 consumption through the diet should be promoted.

Neuropsychiatric Lupus and Lupus Nephritis Successfully Treated with Combined IVIG and Rituximab: An Alternative to Standard of Care.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with unpredictable course and flares. The clinical manifestation can vary from mild to severe and life-threatening disease. Infection is the primary cause of mortality in hospitalized SLE patients. There is a paucity of evidence to support the co-management of SLE with major organ involvement and sepsis. We describe the clinical response of a 35-year-old male diagnosed with SLE; then, he developed severe sepsis and a flare of SLE with major organ involvement including lupus nephritis (LN), myocarditis, and neuropsychiatric systemic lupus erythematosus (NPSLE). Based on the patient's condition, a treatment dilemma was encountered, and after a multidisciplinary meeting, the decision was made to use a combination of rituximab (RTX), intravenous immunoglobulin (IVIG), and pulse steroid. Shortly, the patient's condition started to improve, and his symptoms were resolved. In conclusion, our clinical case suggests that combined RTX, IVIG, and pulse steroid seem to be effective and safe in achieving clinical response, thus representing a good choice for managing severe SLE flares in sepsis.

High gain chopper supplied from PV system to fed synchronous reluctance motor drive for pumping water application.

Power generation for renewable energy sources increased rapidly during last few years. Similarly, the high gain dc-dc boost choppers are taking place of conventional power converters used for photovoltaic (PV) appliances. Researchers are developing different methods in order to provide high voltage gain, low ripple, reduced switch stress, low converter costs, and minimized variations of PV operating points. This study proposes a two-stage converter for a freestanding water pumping motor drive power by solar PV system. According to the proposed system, at first, a high gain (HG) cell and a DC-to-DC boost converter are combined to increase the PV voltage to high levels. Later on, the resulting dc voltage feds a three-phase synchronous reluctance motor drive that operates centrifugal pump load. The perturb and observe approach is utilized to get the maximum power out of the solar PV module. Moreover, indirect field-oriented control is implemented to accomplish smooth starting of synchronous reluctance motor. In order to validate the effectiveness of proposed technique, a MATLAB/Simulink environment-based simulation setup along with an experimental prototype is developed. Additionally, various cases are considered based on different operating conditions and irradiance levels to collect and analyse the results.

Matching-adjusted indirect treatment comparison of the efficacy of enzalutamide versus apalutamide for the treatment of nonmetastatic castration-resistant prostate cancer.

BACKGROUND: To date, the efficacy of the androgen receptor inhibitors enzalutamide and apalutamide for the treatment of nonmetastatic castration-resistant prostate cancer (nmCRPC) has not been compared directly in a clinical trial setting. Indirect comparisons can be used to assess relative efficacy and provide important information to guide treatment decisions. PROSPER and SPARTAN were double-blind, randomized, placebo-controlled, phase III trials in patients with nmCRPC with overall similar study designs and inclusion and exclusion criteria. Using an anchored matching-adjusted indirect comparison, based on the final data from the PROSPER and SPARTAN studies, we assessed the comparative efficacy of enzalutamide and apalutamide, both plus androgen deprivation therapy. METHODS: Using placebo as the common comparator, individual patient data from PROSPER were matched to the aggregate patient data from SPARTAN and efficacy endpoints from PROSPER were re-weighted accordingly. Patient baseline characteristics and endpoints were clinically and statistically tested to identify potential effect modifiers, according to National Institute for Health and Care Excellence guidelines. Hazard ratios for overall survival (OS), metastasis-free survival (MFS), and time to chemotherapy (TTCx) were re-estimated for PROSPER using weighted Cox proportional hazards models and indirectly compared with those of SPARTAN using a Bayesian network meta-analysis. RESULTS: Estimated hazard ratios [95% credible interval (CrI)] for enzalutamide versus apalutamide were 0.80 (95% CrI 0.58-1.10) for OS, 0.94 (95% CrI 0.69-1.29) for MFS2, and 0.90 (95% CrI 0.63-1.29) for TTCx. Similar results were seen for sensitivity analyses conducted for OS and MFS. Bayesian probability analyses showed a 91.7% favoring enzalutamide for OS, 65.1% for MFS, and 71.4% for TTCx. CONCLUSIONS: The results of this matching-adjusted indirect comparison of final data from PROSPER and SPARTAN indicate comparable efficacy of enzalutamide and apalutamide with potentially a greater probability of longer MFS, OS, and TTCx in patients with nmCRPC treated with enzalutamide versus apalutamide.

Impact of Surface Roughness on Flow Physics and Entropy Generation in Jet Impingement Applications.

In this paper, a numerical investigation was performed of an air jet incident that normally occurs on a horizontal heated plane. Analysis of flow physics and entropy generation due to heat and friction is included using a simple easy-to-manufacture, surface roughening element: a circular rib concentric with the air jet. This study shows how varying the locations and dimensions of the rib can deliver a favorable trade-off between entropy generation and flow parameters, such as vortex generation and heat transfer. The performance of the roughness element was tested at three different radii; R/D = 1, 1.5 and 2, where D was the jet hydraulic diameter and R was the radial distance from the geometric center. At each location, the normalized rib height (e/D) was increased from 0.019 to 0.074 based on an increment of (e/D) = 0.019. The jet-to-target distance was H/D = 6 and the jet Reynolds number (Re) ranged from 10,000 to 50,000 Re, which was obtained from the jet hydraulic diameter (D), and the jet exit velocity (U). All results are presented in the form of entropy generation due to friction and heat exchange, as well as the total entropy generated. A detailed comparison of flow physics is presented for all ribs and compared with the baseline case of a smooth surface. The results show that at higher Reynolds numbers, adding a rib of a suitable height reduced the total entropy (St) by 31% compared to the no rib case. In addition, with ribs of heights 0.019, 0.037 and 0.054, respectively, the entropy generated by friction (Sf) was greater than that due to heat exchange (Sh) by about 42%, 26% and 4%, respectively. The rib of height e/D = 0.074 produced the minimum St at R/D = 1. As for varying R/D, varying rib location and Re values had a noticeable impact on Sh, Sf and (St). Placing the rib at R/D = 1 gave the highest total entropy generation (St) followed by R/D = 1.5 for all Re. Finally, the Bejan number increased as both rib height and rib location increased.