bluuebunny/crossref_metadata_2025 huggingface dataset:
Anesthetic management of cesarean sections in coronavirus disease 2019 patients at our coronavirus disease center
Authors: Sinha Chandni , Kumari Poonam , Bhadani Umesh K. , Anant Monika , Shettru Kotresh Arun
Published: September 2024

Coronavirus disease 2019 (COVID-19) is a contagious pulmonary infectious disease with respiratory symptoms. The virus, SARS-CoV-2 has shown 85% resemblance to SARS coronavirus (SARS-CoV) and MERS coronavirus (MERS-CoV). The management of a COVID-19 positive mother is challenging as the virus is extremely contagious and can be life threatening to mothers and health-care personnel. Here, we describe the successful anesthetic management of 20 pregnant women with confirmed COVID-19 infection undergoing cesarean section in our hospital. A dedicated operating room was used for cesarean delivery of a parturient with COVID-19. This dedicated operating room was located in the secluded area of our hospital, away from the rest of the operating rooms. The first choice of anesthesia was a single-shot subarachnoid block with 0.5% heavy bupivacaine.
Comparison between low-dose intravenous and caudal dexamethasone as adjuvants to caudal bupivacaine in children undergoing lower abdominal surgeries
Authors: Abdelrazik Amr N. , Raouf Mina M. , Mousa Sarah O.
Published: September 2024

Background

Caudal block is the most common regional anesthetic technique performed for analgesia for pediatric surgeries. The aim of this study was to evaluate dexamethasone through intravenous and caudal routes as adjuvants to caudal block for postoperative analgesia for pediatric patients who underwent lower abdominal surgeries.

Patients and methods

This prospective, randomized, double-blinded controlled study included 150 children who were divided into three equal groups. All patients received caudal analgesia with 0.125% hyperbaric bupivacaine 1 ml/kg. Group C received an intravenous injection of 10 ml normal saline, group D received 0.1 mg/kg dexamethasone added to the caudal analgesia, and 10 ml normal saline intravenous, while group IV received dexamethasone 0.1 mg/kg in 10 ml normal saline intravenous. The primary outcomes were the duration and severity of postoperative pain. The amount of rescue analgesic doses, residual motor block, and side effects such as nausea, vomiting, and hyperglycemia (secondary outcomes) were monitored.

Results

Dexamethasone groups (D, IV) showed a significantly prolonged duration of postoperative analgesia in comparison to the control group (C) and group D showed a longer duration of analgesia and delayed analgesic rescue when compared with the dexamethasone IV group. CHIPPS was the least in group D compared with group C and group IV at 3, 6, 12, and 24 h. Postoperative nausea and vomiting were significantly lower in group IV compared with the other two groups.

Conclusions

Dexamethasone either caudal or low-dose intravenous was effective for prolonging the duration of analgesia from caudal blockade with bupivacaine, while caudal dexamethasone was more effective. Intravenous dexamethasone had the upper hand in decreasing postoperative nausea and vomiting.
The neutrophil-to-lymphocyte ratio as a prognostic index for short-term outcome in the ICU admitted COVID-19 adult patients
Authors: Kamel Emad Zarief , Sayed Jehan Ahmed , Hashem Maiada K. , Elagan Moataz , Soliman Omar M.
Published: September 2024

Context

The neutrophil-to-lymphocyte ratio (NLR), which can be easily computed from a standard blood test, has been found to be useful in determining a patient’s overall inflammatory condition.

Aim

To find out if the NLR cut-off point could be used to predict mortality in coronavirus disease 2019 (COVID-19) patients admitted to the intensive care unit (ICU).

Setting and design

A prospective cohort study, carried out between March and August 2021, and included 92 COVID-19 ICU admitted patients of Assiut University Hospital.

Methods and material

The NLR, platelet-to-lymphocyte ratio (PLR), ventilation assessment, and short-term outcome were assessed throughout the study period.

Results

Receiver operating characteristic curves analysis on the 7th day was done for NLR and PLR in relation to mortality rate. There was a high AUC for both NLR and PLR (0.946 and 0.931, respectively). The cut-off points were NLR 6.9 and PLR 258.35; above these, the mortality was increased. Patients who were discharged to home were 62 (67.39%), those who were transferred to an intermediate care unit were 9 (9.78%), and those who died were 21 (22.8%).

Conclusion

NLR and PLR levels above a certain threshold were linked to severe COVID-19 and mortality. Prior to clinical application, more research is needed to determine the best cut-off value for NLR.
Continuous sciatic nerve block as preoperative care for lower-limb revascularization surgery
Authors: Linhares Rafael M. , Souza de Lima Marcelo F. , Bersot Carlos D. , Pereira José E.G. , Lobo Clara A.
Published: September 2024

Background

The prevalence of peripheral arterial disease increases with age and it is highly prevalent (15–20%) over 70 years. Surgery can be the best option to resolve the disabling pain. The Anesthesiology and Acute Pain Service routinely adopts continuous popliteal nerve-analgesic block as preoperative care.

Patients and methods

This case series analyzes the medical records of patients under continuous ultrasound-guided sciatic block, during 2 years (2017–2018) before lower-limb revascularization surgery. From a total number of 25 records identified, 15 were selected for analysis. The primary outcome was pain relief from basal line to 24 h postcatheter placement, measured by the Numerical Rating Pain Scale, and the secondary outcomes were reduction of Numerical Pain Rating Scale after 72 h, complications, and possible technical difficulties.

Results

We found pain reduction in the first 24 h of catheter placement, with median Numerical Rating Pain Scale reduction from 10 [interquartile range (IIQ) 10–10] to 0 (IIQ 0–2) (P<0.001); and from 0 to 72 h of catheter placement, with Numerical Rating Pain Scale decreasing median from 10 (IIQ 10–9) to 2 (IIQ 0–2) (P<0.0001). Four (26.7%) patients had their catheters displaced, and in another four (26.7%) patients, hyperemia was observed around the catheter’s introduction ostium on the skin.

Conclusion

Preoperative continuous sciatic nerve block seems to be an effective and safe approach for pain management of peripheral vascular occlusive disease patients waiting for surgery.
Lidocaine versus dexamethasone for reduction of sore throat after general anesthesia
Authors: Mohammed Mohammed N. , El Said Rashad Ali
Published: September 2024

Background

Postoperative sore throat (POST) is commonly reported by patients after endotracheal intubation. This study was conducted to compare the efficacy of intravenous lidocaine and dexamethasone in the prevention of such problem.

Patients and methods

We included a total of 394 cases who were randomly divided using the closed-envelope method into two groups: group D that included 197 cases who received intravenous dexamethasone (8 mg), and group L that included the remaining 197 cases who received intravenous lidocaine (1.5 mg/kg). Both the incidence and risk factors for POST were assessed.

Results

Sore throat was reported by 115 (58.4%) cases in group L, whereas it was reported by 82 (41.6%) cases of cases in the other group. There was a marked reduction of sore-throat sensation in group D (P<0.001). Logistic regression revealed that the presence of blood on suction was a significant risk factor for developing sore throat after intubation.

Conclusion

Intravenous administration of dexamethasone appears to be more promising than lidocaine in decreasing the incidence of POST.
Effectiveness of combined pulsed radiofrequency and steroid injection to the dorsal root ganglion in the treatment of postherpetic neuralgia: a prospective randomized clinical trial
Authors: Elhossieny Khadeja M. , Medhat Marwa M. , Elasser Heba M. , Fathi Heba M.
Published: September 2024

Purpose

The present study aimed to evaluate the effectiveness of a combination of pulsed radiofrequency and transforaminal steroid injection to the dorsal root ganglion for the treatment of postherpetic neuralgia (PHN).

Patients and methods

Forty-six patients suffering from thoracic PHN with a duration of between 1 and 3 months were enrolled and were randomly assigned to either steroid group (n=23) or combination group (n=23). The efficacy was assessed by visual analog scale and by recording the dose of anticonvulsant before and after the procedure.

Results

Visual analog scores decreased in both groups in the postintervention period (2 h, 1 week, and 1 month) with no significant difference found between them. Throughout assessments, visual analog scale in the combination group was significantly lower than in the steroid group in third and sixth months. Regarding the dosage of anticonvulsant, in the first follow-up visit 1 week from intervention, the same preintervention dose of pregabalin was prescribed and then the dose was gradually decreased until the first month in both groups. In the steroid group, the dose was increased again after the first month, while in the combination group there was a gradual decease in the dose. The dose was significantly lower in the combination group compared with the steroid group in third and sixth months.

Conclusion

Pulsed radiofrequency in combination with steroid injection is more effective and lasting for a longer duration than the transforaminal steroid injection alone when used for controlling of pain in patients with thoracic PHN.
Two versus five bilateral local anesthetic injections for submucosal resection
Authors: Naja Zoher , Kanawati Saleh , Naja Ahmad S. , Ziade Fouad
Published: September 2024

Background

Submucous resection (SMR) is performed under general anesthesia, local anesthesia, or a combination of both. The combination was associated with less postoperative pain and shorter hospital stay. The purpose of this clinical trial was to compare the effectiveness of two versus five bilateral local anesthetic injections in terms of postoperative pain relief at 24 h postoperatively.

Patients and methods

This was a prospective, randomized, double-blind clinical trial conducted at a tertiary care center between May 2015 and December 2016. Patients aged between 15 and 63 years scheduled for elective SMR of the nasal septum were included. Eligible patients received general anesthesia and were randomly assigned to receive either two or five bilateral local anesthetic injections. The primary outcome was pain assessed by the Numeric Rating Scale. Other outcomes were hemodynamic stability, analgesic consumption, nausea and vomiting, as well as patient’s and surgeon’s satisfaction.

Results

A total of 120 patients were included in the study and were divided equally into the two groups. Both groups were similar in terms of age, height, weight, surgery duration, and hemodynamic characteristics. There was no significant difference for both groups in pain scores at 24 h (1.53±1.25 vs. 2.07±1.82, P=0.069 for two vs. five injections, respectively) and over the 10 postoperative days. Similarly, the number of patients who consumed analgesics was similar between the two groups.

Conclusion

The present study revealed that two bilateral local anesthetic injections at the suprazygomatic and infraorbital areas could be an alternative to five injections in patients undergoing SMR.
Brake Particle Emission Influenced by Grooved Disc Friction Surfaces with or without a Hard Coating
Authors: Cai Ran , Nie Xueyuan , Lyu Yezhe , Wahlstrom Jens
Published: September 2024

Many performance sport passenger vehicles use drilled or grooved cast iron brake rotors for a better braking performance or a cosmetic reason. Such brake rotors would unfortunately cause more brake dust emission, appearing with dirty wheel rims. To better understand the effects of such brake rotors on particle emission, a pin-on-disc tribometer with two particle emission measurement devices was used to monitor and collect the emitted airborne particles. The first device was an aerodynamic particle sizer, which is capable of measuring particles ranging from 0.5 to 20 μm. The second device was a condensation particle counter, which measures and collects particles from 4 nm to 3 μm. The testing samples were scaled-down brake discs (100 mm in diameter) against low-metallic brake pads. Two machined surface conditions (plain and grooved) with uncoated or ceramic-coated friction surfaces were selected for the investigation. The results showed that the grooved friction surface led to a higher particle emission than a plain friction surface finish. The ceramic coating can indeed reduce the negative effect of the grooving through reductions of both the brake wear and particle emission.
Niobium Alloyed Ferritic Nitrocarburized Brake Rotors
Authors: Holly Mike
Published: September 2024

Niobium (Nb) alloyed Grey cast iron in combination with Ferritic Nitrocarburize (FNC) case hardening heat treatment is proposed to improve wear resistance and reduce brake dust generation of brake rotors. Standard Eutectic and Hypereutectic Grey irons alloyed with Niobium were evaluated in comparison to baseline unalloyed compositions. Brake speed snub sensitivity tribological testing was performed on a matrix including Niobium alloyed, Unalloyed, FNC, Non FNC, Non-Asbestos Organic (NAO) friction and Low metallic (Low Met) friction materials. Full size brake rotors were evaluated by Block Wear and Corrosion Cleanability.

Improved wear, corrosion resistance and reduced brake dust debris were demonstrated by the Niobium alloyed FNC brake rotor combinations. Corrosion is an important consideration when evaluating brake performance. Combining cyclic corrosion and brake rotor testing provides the best comparison with field exposure.
Objectively Quantify Creep Groan and Dynamic Grunt Performance of Different Brake Friction Materials
Authors: Barot Ankit , Wang Weicherng
Published: September 2024

The assessment of brake friction materials extends beyond squeal noise and thermal roughness testing as it play crucial role in other brake noise phenomena such as creep groan and dynamic grunt. These low frequency noise types are significant as they directly affect passengers comfort levels. Creep groan noise defined as audible stick-slip noise at low vehicle speed during partial brake application, typically encountered in dense traffic conditions. Dynamic grunt is another form of stick-slip noise observed during high-speed braking and it is noticeable just prior to vehicle’s complete stop. This noise is indicative of frictional interaction between the brake pad and disc under deceleration scenario. Comparative analysis of two distinct brake friction materials was conducted utilizing both NVH dynamometer and real-world vehicle testing. The NVH dynamometer procedure was designed to evaluate the creep groan and dynamic grunt phenomena under controlled environmental conditions. For the creep groan assessment, a static motor varied speed between 0 and 2 kph under a constant brake pressure, whereas the dynamic grunt evaluation involved applying various braking speeds at different deceleration rates. Vehicle testing for dynamic grunt evaluated under varied temperature and humidity conditions, with the procedure repeated after 10,260 and 510 burnish stops to gauge materials performance consistency over time. Objective quantification of the dynamometer test data was achieved by analyzing peak-to-peak vibration amplitudes from accelerometer channel, vibration duration, brake torque variation, spectral density within the 0 to 1000 Hz range. In contrast, the vehicle tests relied on subjective evaluations from the drivers to gauge noise characteristics. The test results demonstrated the significant impact of the friction materials on both the dynamometer and vehicle testing outcomes. Material A exhibited superior performance, evidenced by notably lower peak-to-peak vibration amplitudes and spectral density values compared to Material B, implying the importance of material selection in mitigating undesirable brake noise phenomena.
Glow Discharge Optical Emission Spectroscopy Study of Cr(III) Sealing in Anodized Aluminum-Silicon Alloys
Authors: Pavesi Arianna , Fumagalli Luca , Abello Mary Angel , Bonfanti Andrea , Mancini Alessandro , Vedani Maurizio , Bertasi Federico
Published: September 2024

The work investigates the penetration depth of a low environmental impact Cr(III)-based sealing on two anodized Aluminum-Silicon alloys (i.e., EN AC-42200 and EN AC-43200) for brake system applications. EN AC-42200 and EN AC-43200 specimens are: 1) obtained by sectioning of gravity cast components; 2) anodized using different process times to obtain different anodic layer thicknesses; and 3) sealed in a Cr(III)-based proprietary sealing solution at low temperature. The obtained sealed anodic layers are characterized using several techniques including: Glow Discharge Optical Emission Spectroscopy (GDOES), metallographic analyses and Eddy current thickness measurements. Results demonstrate that: a) the Cr(III) concentration within the anodic layers shows an exponentially decreasing trend from the specimen surface toward the anodic layer-substrate interface; b) the typical thickness of the sealing layer is in the order of 1.5μm; and c) the Cr(III) penetration depth is only marginally affected by the thickness of the anodic layers and composition of the Aluminum-Silicon alloy under investigation.
Application of Topology Optimization and Artificial Intelligence based Evolutionary Algorithm to Minimize the Contribution of the Caliper in Brake Squeal Noise
Authors: Kumar Dinesh , Inoue Hayuru , Yamamoto Masayuki , Khare Prashant , Kasahara Teruyasu , Hasegawa Keita
Published: September 2024

The squeal noise is one of the critical factors to qualify a disc brake design from the Noise Vibration and Harshness (NVH) perspective. It is imperative to be watchful of the unstable natural modes of the brake assembly which trigger squeal. Any design modification for reducing a part’s contribution to targeted squeal mode can adversely affect and give rise to new squeal modes. Also, controlling conflicting requirements like mass, strength, and casting manufacturability, further adds up complexity, which increases design iterations and product cost. In view of these challenges, the application of the topological optimizations embedded under an artificial intelligence (AI) driven optimization workflow is explored. The scope of optimization is kept limited only to the caliper. Complex eigenvalue (EV) finite element analysis (FEA) of baseline design brake assembly is performed which predicts critical squeal mode having 34% strain energy contribution from caliper. To improve the squeal performance, surface morphing-based shape optimization with mode tracking is explored, which can be useful in the finetuning stages of the design. However, at the initial stages, topological optimizations play an important role in obtaining suitable concepts. Since commercial topological optimization tools do not support complex EV analysis, an integrated & automated workflow is developed. In this, the caliper geometry is first topologically optimized for mass, stiffness, casting manufacturing constraints, followed by complex EV analysis of the optimized geometry. A dummy thermal analysis is included in topology optimization, which equivalently simulates irrotational inviscid fluid flow to improve casting filling performance. Furthermore, a computational fluid dynamics (CFD) solver is added to the workflow to simulate the viscous flow effects during filling process. AI based evolutionary multi-objective optimization algorithm is used to perform multi-disciplinary optimization on the caliper geometry. The best candidate obtained from virtual design iterations exhibited significant reduction in caliper’s strain energy contribution to 9% or less in squeal all modes, reduction in number of squeal modes while having better strength as compared to baseline design with controlled weight addition.
Establishing a Method of Optimizing Wheel Bearing Outer Ring Design for Bearing Life Using a Surrogate Model
Authors: Kitada Tatsuya , Seki Makoto , Imanaka Hironori
Published: September 2024

Wheel bearings play a critical role in providing smooth rotation when vehicles move in straight line and turning motions. If a wheel bearing catastrophically fails, there is the possibility of vehicle damage or even personal injury. Since this is the case, wheel bearings require a higher level of reliability and robustness. With the drive towards a carbon neutral society against the background of global warming in recent years, the demand for lightweighting and lower friction for wheel bearings has become a priority. Weight reductions will cause larger deformation of each bearing component, and especially raceway deformation of the outer ring will impact bearing life. Therefore, optimization of the outer ring geometry is required to meet bearing life requirements and to achieve a lightweight design. In this research, we clarified not only the relationship between outer ring raceway deformation and multiple outer ring geometries under turning load using FEM (Finite Element Method) but also between outer ring shape and bearing life. After performing FEM for multiple outer ring shapes by design of experiments, we calculated both deformation in the raceway and bearing life. As a result, we can predict bearing life given deformation of the outer ring, defining each dimension of the outer ring as design variable using the response surface method. Our findings reveal that optimizing the outer ring geometry significantly enhances bearing life while achieving a lightweight design.
An Archive-Based Micro Genetic Algorithm Approach for Optimizing Wheel Bearing Performance and Reducing Friction
Authors: Bogliacino Fabio , Re Paolo , Ferrero Alessandro
Published: September 2024

Cars and vans are accountable for 14.5% of the total CO2 emissions in the European Union, exerting a significant impact on public health and the environment. To align with the climate objectives set by the Council and the European Parliament, the Fit for 55 package encompasses a series of proposals aimed at revising and modernizing EU legislation while introducing new initiatives. The ultimate goal is to ensure that EU policies are in harmony with the climate targets, specifically the EU’s aspiration to reduce greenhouse gases (GHGs) by at least 55% by 2030 compared to 1990 levels and achieve climate neutrality by 2050. To meet the fleet average emissions targets, automotive Original Equipment Manufacturers (OEMs) are compelled to reduce emissions from their vehicles by addressing various components. The urgent need for car makers to reduce their carbon footprint, combined with the imperative to improve the mileage range of electric vehicles, has led to the creation of a novel methodology.

This approach focuses on optimizing car wheel bearing performance, with a particular emphasis on reducing friction. In contrast to traditional methodologies relying on Design of Experiments (DOE) investigations, the newly developed tool leverages an Archive-based Micro Genetic Algorithm (AMGA) for optimization. This algorithm excels in identifying the optimal bearing design within a constrained timeframe and significantly reduces the number of calculations required. Consequently, this innovation leads to a streamlined customer response process with a notably reduced lead time and fully customized design. The tool comprehensively improves bearing performance by evaluating the internal design geometry to assess ball set friction and identifying optimal dimensions for the seal design.

The objective of this paper is to delineate the comprehensive process involved in setting up and executing optimization, beginning with the identification of the most suitable algorithm. The paper further details the formulation of the optimization strategy tailored to meet customer requirements, highlights the key design factors identified for optimization and concludes by presenting the optimization results that underscore the potential for friction reduction. This holistic exploration covers the entire spectrum of optimization, offering insights into algorithm selection, strategy customization, and the tangible benefits achieved through friction reduction in the outcomes.
Evaluation of Friction Torque in Tapered Roller Bearings
Authors: Lee Seungpyo , An Hyun Gyu
Published: September 2024

A bearing is a mechanical component that transmits rotation and supports load. Depending on the type of rotating mechanism, bearings are categorized into ball bearings and tapered-roller bearings. Tapered-roller bearings are superior to ball bearings in load-bearing capabilities. They are used in applications where high loads, such as, the wheel bearings for commercial vehicles and trucks, aircraft, high-speed trains, and heavy-duty spindles for heavy machinery must be supported. The demand for reducing the friction torque in automobiles has recently increased owing to carbon-emission regulations and fuel-efficiency requirements. Therefore, research on the friction torque of bearings is essential; studies have been conducted on lubrication, friction, and contact in tapered-roller bearings. There have also been studies on lip friction, roller misalignment, and so on; however, research on the influence of roller geometries and material properties is scarce. This study investigated the friction torque of tapered-roller bearings taking roller geometries and material uncertainties into consideration. The friction torque of tapered-roller bearings subject to axial loads was calculated theoretically and compared to experimental results. A Monte Carlo simulation was performed to evaluate the influence of roller geometries and material uncertainties on the friction torque of the bearings. The results of the Monte Carlo simulation showed a distribution skewed to the left. A correlation analysis of the random variables suggested that the outer raceway half angle and rib angle had a significant impact on the friction torque. In conclusion, the method proposed in this study enables the identification of factors influencing the torque of tapered-roller bearings. It is anticipated that these results can be utilized in the design of tapered-roller bearings.
Comprehensive Study on Challenges to Introduce Autonomous Emergency Braking (AEBS) Feature in Indian Perspective
Authors: Kartheek Nedunuri , Khare Rashmita , Sathyamurthy Sainathan , Manickam Praveenkumar , Kuchipudi Venkata Sai Pavan
Published: September 2024

India is a diverse country in terms of road conditions, road maintenance, traffic conditions, traffic density, quality of traffic which implies presence of agricultural tractors, bullock carts, autos, motor bikes, oncoming traffic in same lane, vulnerable road users (VRU) walking in the same lanes as vehicles, VRU’s crossing roads without using zebra crossings etc. as additional traffic quality deterrents in comparison to developed countries. The braking capacity of such vivid road users may not be at par with global standards due to their maintenance, loading beyond specifications, driver behavior which includes the tendency to maintain a close gap between the preceding vehicle etc. which may lead to incidents specifically of rear collisions due to the front vehicle going through an emergency braking event. The following paper provides a comprehensive study of the special considerations or intricacies in implementation of Autonomous Emergency Braking (AEBS) feature into Indian traffic perspective. The paper provides a comparison of the AEBS standard between Indian and EU markets. The paper provides the differences in traffic quality of Indian roads in comparison with EU to justify the limitations to be dealt with and eventually this paper also provides a detailed study on the special considerations to be inculcated in developing such feature specific to Indian customer and to enhance the safety of occupant as well as other road users.
Research on Acceleration Slip Regulation for Battery Electric Vehicle
Authors: Kang Kailei , Liu Xingchen , Liu XinHong
Published: September 2024

As an important part of the automobile electronic control system, the acceleration slip regulation takes the tire slip rate as the main control target. By controlling the wheel driving force, the tire maintains a stable adhesion state to obtain good driving stability and power. This paper takes battery electric vehicles as the research object and explores the application of acceleration slip regulation in vehicle drive control. In order to obtain the true vehicle speed when the wheel slips, a vehicle speed observer based on extended Kalman Filter is proposed. Secondly, this paper designs a road surface recognition method based on fuzzy theory, which obtains the optimal slip rate under current road conditions by taking the actual slip rate and road surface adhesion coefficient as input. When a vehicle is driving on a road with different adhesion coefficients on the left and right sides, one side of the wheel may slip severely while the opposite side wheel does not slip. In order to ensure the longitudinal stability of the car while driving, this paper designs a torque distribution system based on the optimal slip rate. Then, through software Carsim/simulink Co-simulation, the simulation results are analyzed and it is found that the acceleration slip regulation designed in this paper has good implementation effects and significant Improves the longitudinal stability and safety of the vehicle.
Modelling and Simulation of Electronic Brake Booster with Fuzzy Logic Control
Authors: Soliman Amr M.E. , Kaldas Mina M. , Soliman Aref M.A. , Huzayyin Ahmed
Published: September 2024

On one hand, simulation tools are widely used to study and examine new technologies before building prototypes. It is a cost and time saver if it is mathematically modeled with and simulated in real time with sufficient fidelity. On the other hand, the expansion of electric and hybrid vehicle development requested advancing the Electronic Brake Booster (EBB) technologies. In this paper, a simulation tool for the EBB is developed to simulate the performance in real time with a very quick response compared to the previous models with a novel fuzzy logic control (FLC) for the position tracking control. The configuration of the EBB is established, and the system model, including the permanent magnet synchronous motor (PMSM), a double reduction transmission (gears and a ball screw), a servo body, a reaction disc, and the hydraulic load, is modeled. The load-dependent friction has been compensated by using the Karnopp-friction model. FLC has been used for the control algorithm. The control concept focused on transforming the pressure control of the EBB into position tracking control to overcome the nonlinearity and achieve the control process with the required precision and dynamics. The EBB simulation model has been developed using MATLAB/Simulink, and an ode4 Runge-Kutta solver with a step size of 10 milliseconds is used to solve the differential equations of the model. In order to present the reliability of the developed simulation model, a comparison was made with a widely referenced and validated EBB model that was developed to simulate the performance. The simulation results showed a very good correlation between the developed model and the widely referenced model. In addition to that, the developed model is able to simulate the performance of the EBB faster than the widely referenced model and has real-time behavior.
Application of Machine Learning Models to Enable Virtual Development of High Performance Brake Systems
Authors: Antanaitis David
Published: September 2024

The once rarified field of Artificial Intelligence, and its subset field of Machine Learning have very much permeated most major areas of engineering as well as everyday life. It is already likely that few if any days go by for the average person without some form of interaction with Artificial Intelligence. Inexpensive, fast computers, vast collections of data, and powerful, versatile software tools have transitioned AI and ML models from the exotic to the mainstream for solving a wide variety of engineering problems. In the field of braking, one particularly challenging problem is how to represent tribological behavior of the brake, such as friction and wear, and a closely related behavior, fluid consumption (or piston travel in the case of mechatronic brakes), in a model. This problem has been put in the forefront by the sharply crescendo-ing push for fast vehicle development times, doing high quality system integration work early on, and the starring role of analysis-based tools in enabling this strategy. Focusing even further, brake corner systems under duress – such as high temperatures, and high braking power, can exhibit highly non-linear and in-stop varying behavior that can be exceedingly difficult to model accurately. The present work chronicles efforts by the author and colleagues to develop machine learning models that capture this complex behavior and generalize sufficiently well to continue representing the performance of the brake under high energy driving conditions, even as the models are presented with new braking conditions that were not part of the training of the models. The utility of the models in the prediction of system-level performance is demonstrated through a case study application to calibrating a fade warning feature. The present work is shown from the perspective of a practicing engineer, not a data scientist, with some details that may prove mundane to the latter – but a strong motivation behind this work is to share the experience of getting started and some practical lessons learned towards the use of these powerful machine learning tools to solving practical problems in the field of brake engineering.
Brake Heat Capacity Prediction Using a Machine-Learned Friction Coefficient Model and Virtual Wheel Brake
Authors: Cho Sunghyun , Baek SangHeum , Kim Min Soo , Hong Incheol , Kim Hyun Ki , Kim Gwichul , Lee Jounghee
Published: September 2024

Recently, the increasing complexity of systems and diverse customer demands have necessitated the development of highly efficient vehicles. The ability to accurately predict vehicle performance through simulation allows for the determination of design specifications before the construction of test vehicles, leading to reduced development schedules and costs. Therefore, detailed brake thermal performance predictions are required both for the front and rear brakes. Moreover, scenarios requiring validation, such as alpine conditions that apply braking severity to xEV with the regenerative braking system, have become increasingly diverse. To address this challenge, this study proposes a co-simulation method that incorporates a machine-learned brake pad friction coefficient prediction model to enhance the accuracy of brake thermal capacity predictions within the vehicle simulation environment. This innovative method allows for the simultaneous prediction of both front and rear-wheel brakes. The required brake torques for the front and rear wheels are calculated based on the vehicle model and driving scenarios. The brake system model generates the necessary pressure during deceleration, whereas the friction coefficient is crucial in creating brake torque, resulting in brake power for both the front and rear brakes. Within the simulation model, the virtual wheel brake calculates the speed, pressure, and disc temperature based on vehicle driving schedules. The machine-learned model utilizes these variables as inputs and returns the friction coefficient. The prediction accuracy of torque and disc temperature improved significantly as the virtual wheel brake utilized the friction coefficient received from the model trained using the mixed-effects random forest algorithm.
Moisture Adsorption and Compression Deformation Behavior of Semimet vs. NAO Brake Pads: Effect of Pad Cure Temperatures and Moisture Adsorption on Low-Speed Friction
Authors: Rhee Seong Kwan , Rathee Aman , Singh Shivraj , Sharma Devendra
Published: September 2024

Moisture adsorption and compression deformation behaviors of Semimet and Non-Asbestos Organic brake pads were studied and compared for the pads cured at 120, 180 and 240 0C. The 2 types of pads were very similar in moisture adsorption behavior despite significant differences in composition. After being subjected to humidity and repeated compression to 160 bars, they all deform via the poroviscoelastoplastic mechanism, become harder to compress, and do not fully recover the original thickness after the pressure is released for 24 hours. In the case of the Semimet pads, the highest deformation occurs with the 240 °C-cure pads. In the case of the NAO pads, the highest deformation occurs with the 120 0C-cure pads. In addition, the effect of pad cure temperatures and moisture adsorption on low-speed friction was investigated. As pad properties change all the time in storage and in service because of continuously changing humidity, brake temperature and pressure, one must question any approach trying to relate unused virgin pad properties to brake friction and noise in service, including any attempt to model or simulate brake friction and noise using virgin pad properties.
Cumhuriyet Kavramına İlişkin İlkokul Öğrencilerinin Metaforik Algıları
Authors: Yılmaz Büşra , Yıldız Kaya
Published: September 2024

Öz
Bu araştırmanın amacı ilkokul öğrencilerinin Cumhuriyet kavramına yönelik metaforik algılarını saptamaktır. Araştırmanın çalışma grubunu, 2023-2024 eğitim-öğretim yılının birinci döneminde Bolu ili Merkez ilçe sınırları içerisindeki bir ilkokulda öğrenim gören 2.sınıf, 3.sınıf ve 4.sınıf toplam 486 öğrenci oluşturmaktadır. Öğrencilerin Cumhuriyet kavramına yükledikleri metaforik anlamların ortaya çıkartılıp incelenmesini amaçlayan bu çalışmada, olgubilim (fenomenoloji) deseni kullanılmıştır. Araştırma verilerini toplamak için, kodlama, temaların bulunması, verilerin kod ve temalara göre örgütlenmesi aşamalarından oluşan yarı yapılandırılmış görüşme formu kullanılmıştır. Verilerin analizinde içerik analizi kullanılmıştır. Öğrencilerin algılarına dayalı olarak Cumhuriyet kavramına ilişkin tüm sınıflarda ortak 48 metafor, bireysel 176 metafor olmak üzere toplam 224 adet metafor üretilmiştir. Öğrenciler tarafından üretilen en çok beş metafor incelendiğinde sırasıyla; Özgürlük, Bayram, Güneş, Atatürk ve Bayrak olduğu görülmektedir. Öğrenciler tarafından üretilen 224 adet metafor araştırmacılar tarafından 9 kategori altında toplanmıştır. Bu kategoriler; Bağımsızlık, Değer, Güç, Güven, İlerleme, Öncü, Şenlik, Yönetim Şekli ve Zafer. Araştırmanın sonuçları incelendiğinde tüm sınıf düzeylerindeki öğrencilerin Cumhuriyet kavramına ilişkin olumlu bir algıya sahip oldukları görülmüştür.
Anahtar Kelimeler: Cumhuriyet, Metafor, Hayat Bilgisi, Sosyal Bilgiler, İlkokul
Dynamical and optimal control analysis of lymphatic filariasis and buruli ulcer co-infection
Authors: Edogbanya Helen Olaronke Edogbanya , Emmanuel Sabastine , Artes Rosalio G Artes Jr , Rasid Regimar A.
Published: September 2024

This study delves into the dynamics of lymphatic filariasis and buruli ulcer coinfection, two overlooked yet impactful tropical diseases. With lymphatic filariasis, commonly referred to as elephantiasis, and buruli ulcer, a chronic affliction caused by mycobacterium ulcerans, both posing significant health challenges, understanding their interaction is crucial. Utilizing a mathematical model, this research aims to analyze the dynamics of this coinfection, elucidating its complexities. The study establishes the local asymptotic stability of the disease-free equilibrium and calculates the basic reproduction number using the next generation matrix. It uncovers transcritical and backward bifurcation phenomena within the model. Additionally, the integration of time-dependent controls enables the exploration of optimal disease management strategies. Numerical simulations highlight the efficacy of employing a comprehensive approach, utilizing all available controls simultaneously, as the most effective strategy for disease control. These findings underscore the importance of integrated interventions in combating lymphatic filariasis and buruli ulcer coinfection, offering valuable insights for public health policymakers and practitioners.
Convolution equation and operators on the Euclidean motion group
Authors: Bassey U. N. , Edeke U. E.
Published: September 2024

Let $G = \mathbb{R}^2\rtimes SO(2)$  be the Euclidean motion group, let g be the Lie algebra of G and let U(g) be the universal enveloping algebra of g. Then U(g) is an infinite dimensional, linear associative and non-commutative algebra consisting of invariant differential operators on G. The Dirac measure on G is represented by $\delta_G$, while the convolution product of functions or measures on G is represented by $\ast$. Among other notable results, it is demonstrated that for each u in U(g), there is a distribution E on G such that the convolution equation $u\ast E = \delta_G$ is solved by method of convolution. Further more, it is established that the (convolution) operator $A^\prime : C^\infty_c(G)\rightarrow C^\infty(G),$, which is defined as $A^\prime f = f\ast T^n\delta(t)$ extends to a bounded linear operator on $L^2(G)$, for $f\in C^\infty_c(G)$, the space of infinitely differentiable functions on G with compact support. Furthermore, we demonstrate that the left convolution operator LT denoted as $L_Tf = T\ast f$ commutes with left translation, for $T\in D^\prime(G)$.
Synthesis and Characterization of MnO2 nanoparticles mediated by Raphia hookeri seed
Authors: Akpeji Bamidele  H. , Lari Bulouebibo , Igbuku Ufuoma A. , Tesi Godswill , Elemike Elias E. , Akusu Paul O.
Published: September 2024

In this study, managanese dioxide nanoparticles (MnO2-NP) was synthesized. Raphia hookeri seed was used as a bioreductant for the synthesis of MnO2-NPs. The biosynthesized MnO2-NPs was investigated for their reaction, structure and morphology. The MnO2-NPs was characterized using the UV-Visible spectrophotometry, Fourier Transform Infrared Spectrophotometry (FTIR), Energy Dispersive Spectrometry (EDX), Powdered X-ray Diffractometry (PXRD), Scanning electron microscpopy (SEM) and Transmission Electron Microscopy (TEM). UV-Visible spectra revealed that MnO2-NPs showed maximum 421nm respectively. FTIR results showed prominent reactive functional groups for hydroxyl (-OH) and carbonyl (-C=O). The EDX results revealed the elemental composition in percentages of the elements in the nanoparticles. PXRD revealled that the manganese dioxide nanoparticle is in a crystaline state. The morphology of the synthesized nanoparticle was found irregular and with porous surface for SEM. The average particle size of the nanoparticles as characterized by TEM was found to be 3.92 nm.
KINETIC AND THERMODYNAMIC ADSORPTION STUDIES ON THE REMOVAL AND TREATMENT OF TEXTILES EFFLUENTS USING ACTIVATED CARBON DERIVED FROM DIOSPYROS MESPILLIFORMIS SEEDS.
Authors: Nwaedozie J.M , Mathew J. , Aliyu A.O. , Agbogo V. U , Nwankwo R.C
Published: September 2024

An agricultural waste Diospyros mespiliformis seeds were treated, and activated with 30% of 0.3M sodium hydroxide base, to obtain an activated carbon employed in an adsorption process. It was utilize to treat effluent textile water sample from African Textile Manufacturers Limited in Dala, Kano State, Nigeria. Various techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and proximate analysis were employed to investigate the adsorption process. The adsorbent was able to remove the dark red color to colorless found in textile effluents and shown a higher removal affinity for zinc ( 99.4%) and least affinity for nickel (0.11%), also Chromium (Cr) reduced by 39.4%, Copper (Cu) reduced by 20.9%, Iron (Fe) reduced by 91.9% , Manganese (Mg) reduced by 79.3%, are reduced significantly, the PH change from acidic PH 6.4 to neutral PH 7.1, turbidity decrease from 131 to 14 NTU , electrical conductivity change from 723 to 110 ?s·cm?1 .Diospyros mespiliformis seeds activated carbon was used for removal of congo red and malachite green from an aqueous solution. The effect of adsorbent dose, adsorbate concentration and contact time on the process of adsorption was investigated. The optimum dosage was found to be 0.5g had a percentage removal of 98.1% for congo red and 94.4% for malachite green. 10mg/l and 80minute was found to optimum concentration and optimum time in adsorption of congo red and malachite green. The equilibrium, kinetic and thermodynamic properties of the dyes removal were also investigated. The experimental data were modeled using linear regression method of analysis. The correlation coefficient was used as a criterion for model adequacy and acceptance. The pseudo second-order kinetic model was found to best correlate the experimental data with R2 of 0.9523 for CR and 0.9297 for MG. The experimental data were investigated at three different temperature, 305k, 325k and 335k were found to follow the Langmuir model with R2 of 0.9679, 0.9662 and 0.989 for CR and 0.9529, 0.9662 and 0.994 for MG. also were found to follow Temkinp model with with R2 of 0.9549, 0.9318 and 0.9952for CR and 0.9885, 0.9443 and 0.9209 for MG. The negative free gribbs energy indicated that the adsorption processes were spontaneously feasible. The positive values of +31.66KJ/mol and +92.3KJ/mol on both CR and MG indicate that adsorption process has been found to be endothermic in nature. The removal of congo red was found to be more spontaneous and feasible than the removal of malachite green on the adsorbent. From the study, it was deduced that the Diospyros mespiliformis seeds activated with sodium hydroxide was found to be a good adsorbent for the treatment of textile wastewater containing Congo red and Malachite green.
COMPETITIVE ADSORPTION OF Fe2+, Pb2+, AND Zn2+ IONS FROM MULTI-METAL ION SOLUTION ON AMMONIUM OXALATE MODIFIED KAOLINITE CLAY
Authors: Lawal J. A. , Olaremu A. G. , Odeyemi O. T. , Omeiza F. S. , Sanni I.
Published: September 2024

The competitive adsorption of Fe2+, Pb2+, and Zn2+ ions from mixed multi-metal aqueous solution on ammonium oxalate-modified kaolinite clay (AOK) was studied to determine the competitive influence of the metal ions on the adsorption of other metal ions. The kaolinite clay was modified by treating it with 0.2 M of ammonium oxalate solution at 50 oC. The adsorption of the metal ions was carried out using initial concentrations of 20, 35, and 50 mg L-1 in both the single and multi-metal ion solutions. The results revealed that at a low concentration of 20 mg L-1, the adsorption capacity for the uptake of the metal ions on AOK is non-competitive. At higher adsorbate concentrations of 35 and 50 mg L-1, the single to multi-metal ions equilibrium adsorption capacity ratio value obtained was less than 1. This indicated an antagonistic effect on competing for the adsorption site in the following order: Pb2+ (9.9 mg g-1) > Fe2+ (3.85 mg g-1) > Zn2+ (2.85 mg g-1). The outcome revealed that ammonium oxalate-modified kaolinite is a potential adsorbent for remediation of multi-heavy metal-laden wastewater with preferentially higher affinity for Pb2+ ions than other metal ions.