bluuebunny/crossref_metadata_2025 huggingface dataset:
Unilateral Purtscher's Retinopathy
Authors: Fuentes-Perez Daniel , Garcia-Roa Marlon , Silva-Lepe Ariadna , Vazquez-Membrillo Miguel
Published: April 2021

We report herein a case of a 17-year-old male who presented status postmotor vehicle accident resulting in severe polytrauma and reduced visual acuity in his right eye (OD). Best-corrected visual acuity (BCVA) was 20/400 OD and 20/20 in his left eye (OS). Slit-lamp examination confirmed normal anterior segment anatomy in both eyes (OU). Indirect ophthalmoscopy and subsequent fluorescein angiography confirmed the presence of multiple cotton-wool spots, intraretinal hemorrhages, a well-circumscribed area of macular whitening, and vascular tortuosity throughout the posterior pole and peripapillary region, all suggestive of an arterio-occlusive event OD, with a normal fundus examination OS. Imaging of the macula with optical coherence tomography demonstrated hyperreflectivity of the inner retina, along with subfoveal irregularities of the outer retinal segments OD. Systemic steroid therapy was initiated, and after 1 month, BCVA improved to 20/70 OD.
Perioperative care of obstructive sleep apnea patients
Authors: Bamgbade Olumuyiwa A. , Oluwole Oluwafemi , Khalaf Wael M. , Namata Christine , Metekia Lidya M.
Published: April 2021

Background:

Obstructive sleep apnea (OSA) is prevalent in the surgical patient population and is associated with high risk of perioperative complications. There are limited guidelines and wide practice variations regarding the perioperative care of obese and OSA patients. This is a study of European anesthesiologists' clinical practice of perioperative care of OSA patients.

Methods:

This survey evaluated United Kingdom anesthesiologists' clinical practice of the perioperative care of OSA patients. Outcomes and variables were compared between 4100 anesthesiologists of different clinical experience and hospital settings.

Results:

Approximately 45% of respondents manage OSA patients rarely, 42% occasionally, and 13% regularly. Most respondents order OSA screening tests if patients have tonsillar hypertrophy, head/neck tumor, BMI >35, increased neck circumference, craniofacial anomaly, and right-sided electrocardiography (ECG) anomaly. Majority request preoperative polysomnography, ECG, overnight pulse oximetry, and arterial blood gas analysis. Majority recommend preoperative weight loss, optimisation, smoking cessation, reduction of substance use, and regular mask-CPAP use. Majority consider endoscopy, and ophthalmology as appropriate day case procedures, but not laparoscopy. Majority postpone elective airway, laparoscopic, laparotomy, and head/neck surgery; if patients are not optimized preoperatively. For major surgery, combined general + neuraxial anesthesia was ranked as 3rd option. For major limb surgery, neuraxial anesthesia without sedation was ranked as 1st option, nerve block without sedation was ranked 2nd, and general anesthesia + nerve block was ranked 3rd or 4th. At anesthesia emergence, majority ensure that patients have normal consciousness, respiration and neuromuscular function. Majority ensure postoperative oximetry, telemetry, and oxygen supplementation.

Conclusion:

This study highlights variations in anesthesiologists' perioperative care of OSA patients; even in developed countries with advanced medical training and standards. The study outcomes will improve perioperative care of OSA patients.
Successful perioperative management of a pediatric patient with medium-chain acyl-CoA dehydrogenase deficiency using a continuous tissue glucose monitoring device
Authors: Hidekazu Ito , Shoji Mizuno
Published: April 2021

Medium-chain acyl-CoA dehydrogenase deficiency can cause symptoms resulting from β-oxidation disorder during preoperative fasting. Tight perioperative glucose monitoring is needed to avoid these symptoms. We report the first pediatric case using continuous tissue glucose monitoring devices. The patient was a 9-year-old boy with medium-chain acyl-CoA dehydrogenase deficiency for whom femoral osteotomy and selective muscle release of the hip and knee was planned to treat hip dislocation and joint contracture. To monitor tissue glucose levels continuously during preoperative fasting, a percutaneous sensor was attached to the right upper extremity, 2 days before the operation. Anesthetic management using Ringer's acetate containing 5% glucose, an inhalational agent, and epidural anesthesia without a muscle relaxant or propofol was performed without complications. The device achieved tight perioperative glucose monitoring. Continuous tissue glucose monitoring devices helped perioperative glucose monitoring of the pediatric patient with medium-chain acyl-CoA dehydrogenase deficiency.
Anaesthetic considerations in Aarskog Scott Syndrome
Authors: Gahlot Divya , Aggarwal Munisha
Published: April 2021

Aarskog Scott syndrome is a rare genetic disorder characterised by facial, limb and genital abnormalities first described in 1970. Its evolving nature in terms of associated features and increased surgical interventions necessitates anaesthesiologists to have a thorough knowledge about this syndrome for a better preparedness. Although multiple case reports have been published in literature since its discovery, no case report regarding its anaesthetic considerations and challenges have been described in literature till now. We report challenges encountered and successful anaesthetic management of a seven-year-old girl with Aarskog Scott Syndrome posted for a corneal repair in view of traumatic corneal perforation.
Comparative evaluation of intubation performances using two different barrier devices used in the COVID-19 era
Authors: Kannaujia Ashish , Haldar Rudrashish , Shamim Rafat , Mishra Prabhakar , Agarwal Anil
Published: April 2021

Background and Aims:

Protection of anaesthesiologists from contaminated aerosols of COVID 19 patients during endotracheal intubation has spurred the development of barrier devices like aerosol boxes and clear transparent plastic sheets and usage of videolaryngoscopes in COVID 19 patients. However, the efficiency, feasibility and difficulties faced by anaesthesiologist while performing endotracheal intubations under barrier devices require scientific validation. This manikin-based pilot study aims to assess the laryngoscopic performances of experienced anaesthesiologists under two different barrier enclosures.

Methods and Materials:

53 anaesthesiologists (14 Consultants and 39 Senior Residents) who were undergoing an airway training module as a part of preparedness for handling the COVID 19 pandemic were recruited. Using an aerosol box over a manikin, the participants attempted intubation using a Glidescope Videolaryngoscope and Macintosh laryngoscopes (GA and MA Groups). Subsequently, intubation was attempted under a transparent plastic sheet using both laryngoscopes (GP and MP groups). Time required for intubation, first pass success rates, subjective ease of intubation and the feedback obtained from the participants were recorded and analysed.

Results:

Time required for accomplishing successful intubation was 38.55 ± 12.16 seconds, 26.58 ± 5.73 seconds, 46.89 ± 15.23 seconds and 37.26 ± 8.71 seconds for GA, MA, GP and MP groups respectively. Time for intubation and difficulty (VAS) was least for Macintosh group with aerosol box (MA) and maximum time was taken in Glidescope group with transparent polythene drape (GP). First attempt success rate for Glidescope groups (GP and GA) were 100% and in MA and MP group was 98% and 96% respectively. Restriction in hand movement and stylet removal were the major difficulties reported

Conclusion:

Longer intubation times were observed while using Glidescope Videolaryngoscopes with either of the two barrier devices in place compared to Macintosh laryngoscopes.
The role of magnesium in perioperative management of intracranial aneurysm surgery
Authors: Choudhary Nitin , Bhalotra Anju R. , Magoon Rohan
Published: April 2021

As the motivation to potentially allow for a more expansive role of opioid-sparing anaesthesia in various surgical specialities transpire with new zeal, promising evidence needs to be accumulated to substantiate the same. Appropriate to this context, the index case series highlight the beneficial effects of an intraoperative magnesium sulphate infusion on perioperative hemodynamic profile and postoperative recovery in patients undergoing intracranial cerebral aneurysm surgery.
The factors affecting nurses' assessments toward pain management in Saudi Arabia
Authors: Samarkandi Osama A.
Published: April 2021

Background and Aims:

Pain assessment requires an extensive practice in diagnosis coupled with proficiency in recognizing health factors that lead to its occurrence. Nurses' education and training could be the main factor influencing pain perception and diagnosis. This study aims at comparing nurses' academic qualifications and relevant training courses that may impact their assessment skills toward patients in pain.

Methods:

A descriptive cross-sectional design using a Knowledge and Attitudes Survey Regarding Pain questionnaire was administered to a total of 247 nurses. In this survey, the nurses were asked to answer specific questions related to correctly diagnosing and assessing patients' pain, as well as answer questions about their previous training in pain assessment.

Results:

A total of 247 nurses answered the questionnaire, with an overall response rate of 82%. Questionnaires revealed that more than half (50.6%) of the nurses involved in this study have not received any pain education related to pain management in the 5 years following their initial nursing licensure or supervision under a nurse supervisor.

Conclusions:

The results of the paper show that nurses' experiential level has the highest impact on their knowledge of pain relief management and medications necessary for treating it. Also, nurses' pain education following their initial licensure and during their professional practice has the second highest impact on their pain relief management knowledge, whereas their primary nursing education had the lowest.
Lumbar erector spinae plane block obtunding knee and ankle reflexes
Authors: Diwan Sandeep , Nair Abhijit
Published: April 2021

The erector spinae plane block (ESPB) has recently been described as an effective analgesic strategy for various surgeries at ventral and dorsal parts of body. The block has been utilized for postoperative pain relief in hip surgeries. Cadaveric and clinical studies performed at the lumbar level depict a dorsal spread and minimal ventral spread in the lumbar plexus. So far to our knowledge there is one case report which has described reduced quadriceps strength in a parturient after caesarean section. We report two patients who presented with absent knee reflexes (decreased quadriceps strength) and one patient with absent ankle reflex (foot drop) following continuous ESPB at the level of L3. The initial bolus was with 30 ml of 0.1% bupivacaine followed by a continuous infusion of 0.1% ropivacaine at 8ml/hour. The loss of knee reflexes in two patients and diminished reflexes in one patient suggested spread of local anaesthetic (LA) to the lumbosacral plexus. The LA infusion were stopped in all 3 patients. The average duration of motor block was 18 hours. These complications should be considered if early ambulation is mandatory for patients.
Intraoperative central diabetes insipidus in a postpartum patient during decompression of base of brain lesion
Authors: Bithal Parmod K. , Jan Ravees , Butt Yasser Majid , Alshuaibi Khalid
Published: April 2021

A 35-year-old female presented with headache in the third week postpartum period following uneventful cesarean delivery. She had left sided ptosis, pain, and numbness over left face since third trimester. Post-delivery magnetic resonance imaging revealed invading left sphenoid sinus meningioma. She was planned for combined endonasal and pterional craniotomy. Her preoperative investigations including sodium, glucose, and liver functions were normal. Intraoperatively during endonasal phase a high urine output (UO) with rising sodium were noticed which continued with worsening sodium (156 mEq/L after 3 h). Desmopressin 1 mcg IV administered which normalized UO for the rest of surgical duration with trends of declining sodium (149 mEq/L at the end of procedure). Her postoperative MRI was normal however desmopressin could not be discontinued because of increasing sodium and UO without it. She was discharged on oral desmopressin, hydrocortisone and levothyroxine. On her follow-up 3.5 months later she had normal sodium and normal UO.
Blind intubation through Laryngeal Mask Airway in a cannot intubate-difficult to ventilate patient with massive hematemesis
Authors: Cataldo Rita , Zdravkovic Ivana , Petrovic Zaklina , Corso Ruggero M. , Pascarella Giuseppe , Sorbello Massimiliano
Published: April 2021

Massive hematemesis could be challenging situation requiring emergency airway control and urgent surgical treatment. We report a case of difficult airway management with blind intubation through Laryngeal Mask Airway in a 56-year-old patient with massive hematemesis. After failed endoscopic attempts to stop bleeding, worsening of hemodynamics called for emergency intubation and surgery. After failed intubation attempts and face-mask ventilation worsening, a classic LMA was used for rescue ventilation and decision was made to intubate through LMA. The airway exchange was aided by a nasogastric tube (NGT) through LMA, confirmed with capnography and surgery was started successfully and uneventfully. Unexpected difficult airway can be extremely challenging situation, especially in emergency settings with no possibility to delay surgery. In those cases, literature suggests different intubating techniques through LMA. Blind intubation through LMA aided by NGT showed to be a suitable option in resources-limited settings, where advanced supraglottic devices and/or optical devices are not available.
The comparison of the efficacy of ultrasound-guided paravertebral block versus erector spinae plane block for postoperative analgesia in modified radical mastectomy
Authors: Agarwal Shilpi , Bharati Sachidanand Jee , Bhatnagar Sushma , Mishra Seema , Garg Rakesh , Gupta Nishkarsh , Kumar Vinod , Khan Maroof Ahmad
Published: April 2021

Introduction:

The ultrasound (US)-guided erector spinae plane (ESP) block is a new regional anesthetic technique that offers significant advantages over paravertebral block as it is easy and safe to perform. We aim to compare the efficacy of US-guided paravertebral block with ESP block for postoperative analgesia in modified radical mastectomy (MRM).

Methods:

Eighty female patients of age group 18–70 years, belonging to physical status American Society of Anesthesiologists (ASA) I and II, undergoing MRM were included in the study. In Group P, patients received paravertebral block and in Group E, patients received ESP block before induction of general anesthesia. Both the groups received 0.5% 20 mL ropivacaine. The time to first rescue analgesia and total doses of rescue analgesics were recorded in the postoperative period. Numeric Rating Scale (NRS) scores at 0 min, 30 min, 1 h, 2 h, 6 h, 12 h, and 24 h were noted, and patient satisfaction was evaluated at 24 h. Unpaired t-test or the Mann–Whitney U test was used to compare quantitative variables while Chi-square test or Fisher's exact test was used to compare qualitative variables.

Results:

The time for the first analgesic request was 232.5 min (140-1200) in ESP group as compared to paravertebral group in which the duration was 205 min (135-1190) (P value = 0.29). The total dose of rescue analgesics and NRS scores in postoperative period were comparable. However, the time to perform ESP block was significantly shorter than that of paravertebral block.

Conclusion:

ESP block can be used as a safe and easy to perform alternative analgesic technique over paravertebral block in breast cancer surgeries.
Cost-effectiveness analysis of colorectal cancer screening in a low incidence country
Authors: Naber Steffie K. , Almadi Majid A. , Guyatt Gordon , Xie Feng , Lansdorp-Vogelaar Iris
Published: April 2021

Background:

Colorectal cancer (CRC) screening is cost-effective in many Western countries, and many have successfully implemented CRC screening programs. For countries with a lower CRC incidence, like Saudi Arabia, the value of CRC screening is less evident and requires careful weighing of harms, benefits, and costs.

Methods:

We used the MISCAN-Colon microsimulation model to simulate a male and female cohort with life expectancy and CRC risk as observed in Saudi Arabia. For both cohorts, we evaluated strategies without screening, with annual or biennial faecal immunochemical testing (FIT), and with 10-yearly or once-only colonoscopy. We also considered different start and end ages of screening. For both cohorts, we estimated lifetime costs and effects of each strategy. We then identified a set of potentially cost-effective strategies using incremental cost-effectiveness ratios (ICERs) defined as the additional cost per additional quality-adjusted life year (QALY).

Results:

Without CRC screening, an estimated 14 per 1,000 males would develop CRC during their lifetime and 9 would die from CRC. Several strategies proved potentially cost-effective including biennial FIT at ages 55-65 (ICER of $7,400), once-only colonoscopy at age 55 (ICER of $7,700), and 10-yearly colonoscopy at ages 50–65, 45–65, and 45–75 (ICERs of $34,000, 71,000, and 375,000, respectively). For females, risk of CRC was lower and CRC screening was therefore less cost-effective, but efficient strategies were largely similar.

Conclusions:

Despite low CRC incidence in Saudi Arabia, some FIT or colonoscopy screening strategies may meet reasonable thresholds of cost-effectiveness. The optimal strategy will depend on multiple factors including the willingness to pay per QALY, the colonoscopy capacity, and the accepted budget impact.
Visual SLAM in Long-Range Autonomous Parking Application Based on Instance-Aware Semantic Segmentation via Multi-Task Network Cascades and Metric Learning Scheme
Authors: Yan Yixiong , Hang Yang , Hu Tianren , Yu Hao , Lai Feng
Published: April 2021

Long-range Autonomous Parking is becoming an attractive application in terms of demands. The vehicle is capable of driving autonomously into the appointed parking slot when the driver leaves it at the drop-off spot. In this application, the ability of accurate localization has become a key issue, especially in GPS-denied environments. This paper proposes a method of localization and mapping for Long-range Autonomous Parking, which is achieved by Visual SLAM based on deep learning algorithms. Firstly, we propose an instance segmentation via multi-task network cascades, and even in a complex visual environment, the main roadway instances of interest in the parking lot IPM image can be detected, such as parking corners, speed bumps. Then we combine the information of wheel encoders to build a global semantic map of the parking lot. Vehicles can often rely on semantic map matching to achieve high-precision localization. However, without a good initial position, it is difficult to infer an accurate position by matching the semantic map, such as randomly selecting entrances to enter the parking lot. Therefore, we propose an area feature network based on metric learning to extract features that distinguish different areas and infer the approximate initial position of the vehicle. Specifically, we extract features from the images of the surround-view cameras, use the vehicle position as weak supervision, and finally construct an area feature map. In summary, our proposed method provides accurate vehicle localization and parking lot maps for Long-range Autonomous Parking.
Investigation of Temperature Distribution inside the Diesel Particulate Filter (DPF) during the Drop to Idle Test (DTIT) Performed at Steady-State and Worst-Case Driving Cycles
Authors: Shankar Radhakrishnan , Chauhan Aadhar , Krishnan Nandhakumar , Chandrasekaran Vasudevan
Published: April 2021

The present work investigates the temperature distribution inside the diesel particulate filter (DPF) regeneration during the drop to idle test (DTIT), which is considered as life-threatening to the DPF. To study this scenario in detail, experiments were carried out with the filter volume of 3 liters. Initially, the experiments were done at a steady-state level, where the optimization for optimal soot loading was performed with setpoint temperature varying from 620 to 660°C. The soot loading was varied from 8 g/l to 11 g/l. The DTIT performed at a steady-state level indicated the different peak temperatures attained inside the DPF at different locations. The peak temperature was found to be in the center plane of the filter. The next peak temperature locations were found to be in downstream of the filter at different locations, which shows the non-uniformity in the soot deposition inside the filter. The temperature gradient was estimated based on the measured peak temperature and was higher at the center plane of the filter. The different soot loading and the setpoint temperature were correlated for different cases. The importance of selecting the optimal soot loading and setpoint temperature were discussed. The time taken from the start of idle speed to reach the peak temperature from the DTI test suggests the importance of the setpoint temperature, which is evident from the fact that it is promoting the burning rate of the accumulated soot with a higher setpoint. Decreasing the soot loading with relaxing the setpoint temperature can be a better option to operate the DPF in the safe zone and to avoid the failure of the DPF. A similar study was carried out at the vehicle level at different operating conditions. The temperature distribution inside the DPF in different worst-case driving maneuvers was measured.
Thermally Conductive Electrically Insulative (TCEI) Materials for E-Motors
Authors: Sundararaman Saikrishna , Szparagowski Ray
Published: April 2021

Engineering plastics are often used in electric components and systems. For these materials, many requirements such as electrical resistance, mechanical properties, temperature capability, flammability, thermal conductivity, moldability etc. are considered for material selection. In general plastics are good electric insulators (electrically safe) but poor conductors of heat (compared to metals). In electric motors, losses due to friction, windage losses, winding losses, iron losses etc. manifest as undesirable heat, resulting in temperature buildup inside the motor. So, choice of materials which offer high thermal conduction and electrical insulation can directly impact motor performance.

Material properties of engineering plastics are greatly influenced by the filler reinforcements used. Although unfilled polymers typically have a thermal conductivity of ~0.2 W/m/K, appropriate choice of fillers can increase this value many-fold. One of the challenges with injection molded plastics is that material properties, including thermal conductivity, are a function of material orientation (orthotropic). In the present work, TCEI materials have been developed for use in bobbins. Freudenberg Sealing Technologies, with its knowledge of filled polymeric systems has developed multiple TCEI grades with improved thermal conductivity compared to commercially available materials. Thermal conductivity measurements on these novel material grades have been conducted to quantify improvements. A finite element model has been developed to capture effect of material choice on temperature distribution within the system. The model incorporates varying material orientation within the bobbin and components within the motor and uses temperature dependent material properties for the analysis. The effect of varying thermal conductivity values on thermal performance and influence of an air gap are studied. Results show that materials with improved thermal conductivity show reduced bobbin and winding temperatures, offering significant performance benefits.
Supervised Terrain Classification with Adaptive Unsupervised Terrain Assessment
Authors: Kurup Akhil , Kysar Sam , Bos Jeremy , Jayakumar Paramsothy , Smith William
Published: April 2021

Off road navigation demands ground robots to traverse complex and often changing terrain. Classification and assessment of terrain can improve path planning strategies by reducing travel time and energy consumption. In this paper we introduce a terrain classification and assessment framework that relies on both exteroceptive and proprioceptive sensor modalities. The robot captures an image of the terrain it is about to traverse and records corresponding vibration data during traversal. These images are manually labelled and used to train a support vector machine (SVM) in an offline training phase. Images have been captured under different lighting conditions and across multiple locations to achieve diversity and robustness to the model. Acceleration data is used to calculate statistical features that capture the roughness of the terrain whereas angular velocities are used to calculate roll and pitch angles experienced by the robot. These features are used to train a k-means clustering classifier, where k is the number of terrain types the robot is expected to encounter. Human intervention is required only to set k. Cluster indices are auto labelled during training. In the operating phase, the SVM predicts the terrain that the robot will encounter and the corresponding cluster center predicts the vibration features associated with that terrain type. These features can be used to assess traversability. Vibration features are measured and the clusters are updated as the robot traverses, thus adapting to change in terrain over time. An accuracy of 92% has been achieved using visual data to classify terrain and 76% to predict the physical properties across different terrain classes.
High-Speed 3D Optical Sensing and Information Processing for Automotive Industry
Authors: Zhang Song
Published: April 2021

This paper explains the basic principles behind two platform technologies that my research team has developed in the field of optical metrology and optical information processing: 1) high-speed 3D optical sensing; and 2) real-time 3D video compression and streaming. This paper will discuss how such platform technologies could benefit the automotive industry including in-situ quality control for additive manufacturing and autonomous vehicle systems. We will also discuss some of other applications that we have been working on such as crime scene capture in forensics.
Stainless Steel Thermal Spray Coating of Cylinder Bores for VC-Turbo Engine
Authors: Hirayama Hayato , Higuchi Tsuyoshi , Hoshikawa Hiroaki , Noshi Yoshitsugu , Terada Daisuke , Oosaki Mototsugu
Published: April 2021

Nissan’s variable compression turbo (VC-Turbo) engine has a multilink mechanism that continuously adjusts the top and bottom dead centers of the piston to change the compression ratio and achieve both fuel economy and high power performance. Increasing the exhaust gas recirculation (EGR) rate is an effective way to further reduce the fuel consumption, although this increases the exhaust gas condensation in the cylinder bores, causing a more corrosive environment. When the EGR rate is increased in a VC-Turbo engine, the combined effect of piston sliding and exhaust gas condensation at the top dead center accelerates the corrosive wear of the thermal spray coating. Stainless steel coating is used to improve the corrosion resistance, but the adhesion strength between the coating and the cylinder bores is reduced. Trial production of the coatings with different linear expansion coefficients was conducted, and the sensitivity of the linear expansion coefficient and adhesion strength was obtained. Consequently, the adhesion strength was found to have a maximum value with respect to the linear expansion coefficient. By contrast, the surface observation of this coating after the honing process showed an increase in surface porosity. The martensitic content in the coating was reduced, and the appropriate martensitic content and chemical composition with the optimal corrosion resistance, adhesion strength, and surface porosity were found. Using this coating (0.01C-12Cr-0.22Ni-0.35Mn), the corrosive wear at the top dead center was resolved. Consequently, the fuel economy was improved by more than 4% compared with that of the current VC-Turbo engine, which has already adopted a carbon-steel-based coating.
Artificial Intelligence for Damage Detection in Automotive Composite Parts: A Use Case
Authors: Ciampaglia Alberto , Mastropietro Antonio , De Gregorio Alessandro , Vaccarino Francesco , Belingardi Giovanni , Busto Enrico
Published: April 2021

The detection and evaluation of damage in composite materials components is one of the main concerns for automotive engineers. It is acknowledged that defects appeared in the manufacturing stage or due to the impact and/or fatigue loads can develop along the vehicle riding. To avoid an unexpected failure of structural components, engineers ask for cheap methodologies assessing the health state of composite parts by means of continuous monitoring. Non Destructive Technique (NDT) for the damage assessment of composite structures are nowadays common and accurate, but an on-line monitoring requires properties as low cost, small size and low power that do not belong to common NDT. The presence of a damage in composite materials, either due to fatigue cycling or low-energy impact, leads to progressive degradation of elastic moduli and strengths. Since there is a well-known relationship between the elastic modulus reduction and the amount of damage, the stiffness degradation can be used for the scope of detecting the position and the amount of damage that has taken place. Relying on these concepts, a novel strain-based damage sensing procedure is here proposed, that can identify damages in composite structures by processing strain measures from a distributed sensors network. To achieve this result a combined Machine Learning pipeline, composed by Principal Component Analysis (PCA) and One Class Support Vector Machine (OC-SVM) is proposed. First, PCA learns a linear transformation on the undamaged measurements to reduce the data dimensionality; secondly, OC-SVM trained to detect anomalies in the projected components. A cross-validation procedure is used to find the optimal pipeline configuration. The methodology is virtually tested on a carbon fiber suspension. The results suggest dropping the first components of the PCA to feed the classifier. In addition, results show the capability of the algorithm to detect anomalies in the component strain response.
EGR Dilution and Fuel Property Effects on High-Efficiency Spark-Ignition Flames
Authors: Dal Forno Chuahy Flavio , Splitter Derek , Wissink Martin , Boronat Colomer Vicente
Published: April 2021

Modern spark ignition internal combustion engines rely on fast combustion rates and high dilution to achieve high brake thermal efficiencies. To accomplish this, new engine designs have moved towards increased tumble ratios and stroke-to-bore ratios. Increased tumble ratios correlate positively with increases in turbulent kinetic energy and improved fuel and residual gas mixing, all of which favor faster and more efficient combustion. Longer stroke-to-bore ratios allow higher geometric compression ratios and use of late intake valve closing to control peak compression pressures and temperatures. The addition of dilution to improve efficiency is limited by the resulting increase in combustion instabilities manifested by cycle-to-cycle variability. A number of effects - preferential diffusion, turbulence-combustion interactions, stochastic flow patterns, laminar-turbulent flame kernel transitions, and relative length and velocity scales between flame and turbulence - are believed to be responsible for the increase in cycle-to-cycle variations, where their contributions are likely interlinked. Several studies have shown the influence of stochastic flow characteristics on the nature of combustion instabilities, such as velocity patterns on flame kernel formation and cycle-to-cycle variations in residual gas. However, few have focused on the specific effects of fuel properties. The objective of this work is to contrast the effects of dilution on propane stoichiometric combustion against gasoline. Dilution tolerance experiments were conducted in a purpose-built high stroke-to-bore ratio single cylinder engine with both gasoline and LPG. Three-dimensional full cycle computational fluid dynamics (CFD) simulations employing a level-set combustion approach and Reynolds averaged Navier-Stokes (RANS) turbulence modeling was used to qualitatively assess the changes in length and velocity scales for turbulence and the flame. The experimental results showed that LPG can tolerate higher exhaust gas recirculation (EGR) dilution under a variety of conditions. Analysis of CFD simulations showed that propane flames are likely less sensitive to influences from the flow field due to less thickening of the flame and higher effective flame speeds.
Design and Modelling of the Powertrain of a Hybrid Fuel Cell Electric Vehicle
Authors: Carello Massimiliana , de Carvalho Pinheiro Henrique , Longega Leonardo , Di Napoli Luca
Published: April 2021

This paper presents a Fuel Cell Electric Vehicle (FCEV) powertrain development and optimization, aiming to minimize hydrogen consumption. The vehicle is a prototype that run at the Shell Eco-marathon race and its powertrain is composed by a PEM fuel cell, supercapacitors and a DC electric motor. The supercapacitors serve as an energy buffer to satisfy the load peaks requested by the electric motor, allowing a smoother (and closer to a stationary application) working condition for the fuel cell. Thus, the fuel cell can achieve higher efficiency rates and the fuel consumption is minimized.

Several models of the powertrain were developed using MATLAB-Simulink and then experimentally validated in laboratory and on the track. The proposed models allow to evaluate two main arrangements between fuel cell and supercapacitors: 1) through a DC/DC converter that sets the FC current to a desired value; 2) using a direct parallel connection between fuel cell and supercapacitors.

The results obtained with the direct parallel connection (with the appropriate sizing of the overall capacity) have highlighted a significant efficiency advantage, while the DC/DC converter insertion enables an improved control of the fuel cell current and requires a smaller capacitance.

Furthermore, a sizing methodology for the supercapacitors capacitance is proposed for both layouts: with the DC/DC converter it mainly depends on the energy range provided by supercapacitors to the electric motor, while in the direct parallel connection the supercapacitors sizing is outlined by concurrently evaluating the circuit’s predicted hydrogen consumption and granting the most suitable conditions to increase the fuel cell performance.

Finally, the results obtained from the model were validated by comparing them with experimental data obtained in the laboratory and on the track.
A Data Driven Fuel Cell Life-Prediction Model for a Fuel Cell Electric City Bus
Authors: Zheng Lu , Hou Yongping , Li Wenqi , Hao Dong
Published: April 2021

Life prediction is a major focus for a commercial fuel cell stack, especially applied in fuel cell electric vehicles (FCEV). This paper proposes a data driven fuel cell lifetime prediction model using particle swarm optimized back-propagation neural network (PSO-BPNN). For the prediction model PSO-BP, PSO algorithm is used to determine the optimal hyper parameters of BP neural network. In this paper, total voltage of fuel cell stack is employed to represent the health index of fuel cell. Then the proposed prediction model is validated by the aging data from PEMFC stack in FCEV at the actual road condition. The experimental results indicate that PSO-BP model can predict the voltage degradation of PEMFC stack at actual road condition precisely and has a higher prediction accuracy than BP model.
Dynamic Modelling of Multiphase Machines Based on the VSD Transformation
Authors: Taylor Joshua , Valencia Garcia Diego Fernando , Taha Wesam , Mohamadian Mustafa , Luedtke Daniel , Nahid-Mobarakeh Babak , Bilgin Berker , Emadi Ali
Published: April 2021

Multiphase machines continue to increase in popularity in high power applications due to their proven benefits compared to their three-phase counterparts. However, with the increased phase number and, therefore, the increased number of degrees of freedom, the complexity of both modelling and control strategies significantly increases. This paper proposes a dynamic modelling method for six-phase interior permanent magnet machines using the vector space decomposition transformation, which can be extended to machines with any number of phases. The proposed technique considers the nonlinear characteristics of the machine, such as spatial harmonics, magnetic saturation, and cross-coupling, which are based on flux linkage look-up tables from finite element analysis. The main contribution of this paper is the consideration of the effect of harmonic components and asymmetries within the machine windings on losses. These effects are mapped into a subspace orthogonal to the conventional dq subspace, which calls for additional transformations based on the field-oriented control structure. The proposed modelling strategy also allows for the inclusion of the high-frequency components generated from the switching instances from an inverter. The accuracy of the proposed model is validated through a comparison of the finite element analysis and Simulink torque waveforms and a comparison of Simulink and experimental current waveforms at low load operating conditions.
Energy-Efficient Braking Torque Distribution Strategy of Rear-Axle Drive Commercial EV Based on Fuzzy Neural Network
Authors: Ge Guoxue , Wang Tao , Lv Yiheng , Zou Xiaojun , Song Wei , Zhang Guofang
Published: April 2021

Regenerative braking is identified as an essential step toward extending cruising mileage for electric vehicle (EV). Braking energy recovery strategies usually focus on passenger EV and commercial EV is ignored. In this paper, an energy-efficient braking torque distribution strategy is proposed for a rear-axle drive commercial EV to improve braking energy recovery and safety. Firstly, the braking force distribution curve is determined referring to the EU braking law for commercial vehicle and the ideal braking distribution curve. Secondly, a novel braking torque distribution strategy is established adopting fuzzy control algorithm, where the ratio between hydraulic braking torque and regenerative braking torque is updated instantaneously according to vehicle velocity, braking strength and state of charge of battery. Then, the corresponding controller is synthesized on ideal braking condition and several classic cycles. To further enhance the performance of the controller, a neural network based framework is established to optimize the membership function in fuzzy controller. Simulations on ideal braking condition demonstrate the controller can always meet emergency braking needs. For the standard cycles, including NEDC and WLTC, the energy-efficient strategy based on fuzzy control can recover up to 18.88% and 16.56% of energy under NEDC and WLTC cycles, and on this basis, the optimized strategy based on adaptive neuro-fuzzy control can improve energy recovery by 2.84% and 3.6% under these two cycles. The developed braking torque distribution strategy can potentially be embedded in real-time supervisory systems to realize the energy saving and increase the cruising mileage for commercial EV.
Identification and Measurement of Best Practice in Implementation of Lean Operation
Authors:   Automotive Quality and Process Improvement Committee
Published: April 2021

SAE J4000 is a tool to identify and measure best practice in the implementation of lean operation in a manufacturing organization. Implementation of lean operation is defined as the process of eliminating waste exhibited in an organization’s value stream. Best practice in this process is Level 3 conduct as described in the standard’s component statements. A description of the levels of implementation is:

A procedure for evaluation and scoring of each component will be included in the SAE J4001 Implementation of Lean Operation User Manual.
Development of a Solar Distiller for the Production of Potable Water for Human Consumption
Authors: Manta I.H. , Awu J.I. , Kasali M.Y. , Ubah J.I.
Published: April 2021

The study is a continual quest towards the provision of affordable, health-friendly fresh potable water in rural areas; using available, affordable and durable materials for the construction of a solar distiller for freshwater production. The aim of this study was to develop a solar distiller for the production of potable water in waterborne diseases infested rural communities in northern Nigeria. Solar radiation with an intensity of 32 kcal/day was made to pass through a transparent polythene of 1039.6 cm2 that covers a 6800 cm3 of water collected through evaporator made with 78% refined clay constituent distilling 1.3 litres/day of pure water. An efficiency of 77% was determined after several test runs. Information from this study will serve as a guide to researchers on the production of portable water from the solar distiller. Also, it will guide the government and agencies on policy and decision making on water resources.

Keywords: Distilling water, solar radiation, collector and evaporator
Editorial
Authors: Bokka Rama Rao
Published: April 2021

No Abstract.
Sacred Kingship and Political Power in Ancient Rwanda
Authors: Nkaka Raphael , Mulinda Charles Kabwete
Published: April 2021

This article revisits the sacred kingship in ancient Rwanda. The existing literature presented it as either obvious or doubtful. Using local sources and exploring theories related to sacred kingship, we argue that the kingship in Rwanda was sacred. We also identify the role that this sacred kingship played in the processes of unification the territory of Rwanda, creation of material culture, origins and consolidation of the kingship and the kingdom. The most important role of the sacred kingship appears to have been mainly the legitimization of the King’s power. We use documentary research and the historical method to present and discuss the following narratives related to the Rwandan kingdom: the tale of origins or the myth of Kigwa, the royal ideology during the reign of Mibambwe III Sentabyo, Gihanga seen as the Incarnation of the Sacred Kingship, the sacrality of Power as source of legitimacy of King Ruganzu II Ndori, and the role of the sacred kingdom through the rituals of the royal court known as Ubwiru.

Key words: Rwandan sacred kingship, power rituals, Rwandan history
Topical Skills for Accounting Graduates within Changing Business Environment: Stakeholders’ Satisfaction Levels in Rwanda
Authors: Nsengiyumva Innocent , Bokka Rama Rao
Published: April 2021

Institution managers have always been seeking competent accountants and accounting technicians to fill the gaps created by the requirements of changing business environment and criticize the existing skills of newly graduated and less experienced accounting job aspirants from Rwandan  Institutions of Higher Learning. This paper analyses the satisfaction levels of various stakeholders in Rwanda towards the skills held by accounting-employees and employers’ expectations, as this could remedy to the competence gap between the job market demand and human resource availability in accounting field. The target population includes the managers of selected institutions in Rwanda, the accountants employed by these institutions and the heads of departments in higher learning institutions delivering accounting programs. The sample was chosen randomly from each stratum of population from the selected districts. The study discovers that the competences acquired are not appropriate to fulfil the necessary skills required in accounting job. Collaboration between accounting firms and academic institutions is needed to synergize accounting practical training with theoretical learning in the classroom. Accountants will also have to equip with other extra knowledge and soft skills (information technology, critical thinking and effective communication) to match the market needs.

Key Words: Business environment, competences, topical skills, accountants, accounting technicians, employers’ requirements,
Conflicting Expectations by Lecturers and Students Regarding the Production of Good Academic Writing: A Case Study at the University of Rwanda
Authors: Twagilimana Innocent , Naidoo Devika
Published: April 2021

In the academic context, lecturers often describe students’ academic writing as very poor whereas the students themselves affirm not to understand the lecturers’ expectations with regard to ‘good writing skills’. This is a report on a study conducted in Rwanda to explore students and lecturers’ expectations of good academic writing. The investigation is underpinned by recent developments in academic writing theories. Based on a qualitative approach and a case study methodology, data were collected by analysing key teaching materials, visiting classes and interviewing academics and students. The findings revealed that lecturers’ conception of teaching and learning academic writing is underpinned by an autonomous view - based on discrete skills. It is recommended that the lecturers’ understanding of the academic literacies approach should be properly developed to meet the expected literacy competence goals.

Key words: ESL, Writing skills, Academic writing, Literacies, Conceptualisation
A preliminary investigation into genotype x environment interaction in South African Holstein cattle for reproduction and production traits
Authors: Neser FWC , Van Wyk JB , Ducrocq V
Published: April 2021

The purpose of the study was to investigate a possible genotype by environment interaction in first calf South African Holstein cows for both production and reproduction traits. Data from 100 975 cows on a total mixed ration (TMR) and 22 083 pasture based cows were used. These cows were the progeny of 4 391 sires and 84 935 dams produced over a period of 11 generations. Traits analysed were milk production (corrected to a 305-day equivalent) and age at first calving (AFC). Both were recorded over a period of 30 years from 1980 - 2010. Production or AFC in each environment (TMR vs. pasture) was treated as a separate trait. Bivariate analyses, fitting an animal model using the ASREML software, were used to obtain genetic correlations between the traits measured in each environment. The fixed factors included were a concatenation of breeder-keeper-year for both milk production and AFC and age at first calving which was fitted as a linear regression for milk production. The random part consisted of the direct additive effects only. The genetic correlation for milk production measured in the two different environments was 0.90 (0.027) and that of age at first calving 0.28 (0.12). The heritability estimates for milk production were 0.23 (0.008) under the TMR system and 0.32 (0.015) for the pasture based system, while the estimates for AFC were 0.063 (0.005) and 0.055 (0.009), respectively. The rather large-scale effect in the heritability (0.23 → 0.32), as well as the correlation of less than one for milk production between the two environments, indicates that a G x E may exist. However, the low genetic correlation between the two environments for AFC is much more real and indicates that G x E should be taken into account when sire selection is performed.Keywords: Age at first calving, milk production, total mixed ration, pasture