bluuebunny/crossref_metadata_2025 huggingface dataset:
Including the Eccentric Phase in Resistance Training to Counteract the Effects of Detraining in Women: A Randomized Controlled Trial
Authors: Coratella Giuseppe , Beato Marco , Bertinato Luciano , Milanese Chiara , Venturelli Massimo , Schena Federico
Published: September 2021

Coratella, G, Beato, M, Bertinato, L, Milanese, C, Venturelli, M, and Schena, F. Including the eccentric phase in resistance training to counteract the effects of detraining in women: a randomized controlled trial. J Strength Cond Res 36(11): 3023–3031, 2022—The current study compared the effects of concentric-based (CONC), eccentric-based (ECC), and traditional concentric-eccentric (TRAD) resistance training on muscle strength, mass, and architecture and the postdetraining retention of the training-induced effects in women. Sixty women were randomly assigned to unilateral volume-equated CONC, ECC, or TRAD knee extension training or control (N = 15 per group). Before training, after an 8-week intervention period, and after an 8-week detraining period, isokinetic concentric, eccentric, and isometric torque were measured. In addition, thigh lean mass was assessed by dual X-ray absorptiometry and vastus lateralis thickness, pennation angle, and fascicle length by ultrasound. After training, concentric and isometric torque increased (p < 0.05) similarly in all groups, whereas eccentric torque increased more in ECC than that in CONC (+13.1%, effect size (ES): 0.71 [0.04–1.38]) and TRAD (+12.6%, ES: 0.60 [0.12–1.08]). Thigh lean mass increased in ECC (+6.1%, ES: 0.47 [0.27–0.67]) and TRAD (+3.1%, ES: 0.33 [0.01–0.65]). Vastus lateralis thickness and pennation angle increased (p < 0.05) similarly in all groups, whereas fascicle elongation was visible in ECC (+9.7%, ES: 0.92 [0.14–1.65]) and TRAD (+7.1%, ES: 0.64 [0.03–1.25]). After detraining, all groups retained (p < 0.05) similar concentric torque. ECC and TRAD preserved eccentric torque (p < 0.05), but ECC more than TRAD (+17.9%, ES: 0.61 [0.21–1.21]). All groups preserved isometric torque (p < 0.05), but ECC more than CONC (+14.2%, ES: 0.71 [0.04–1.38]) and TRAD (+13.8%, ES: 0.65 [0.10–1.20]). Thigh lean mass and vastus lateralis fascicle length were retained only in ECC (p < 0.05), pennation angle was preserved in all groups (p < 0.05), and thickness was retained in CONC and ECC (p < 0.05). Including the eccentric phase in resistance training is essential to preserve adaptations after detraining.
Balancing Injury Risk and Power Development by Weighted Jump Squat Through Controlling Eccentric Loading
Authors: Songsupap Tongthong , Newton Robert U. , Lawsirirat Chaipat
Published: September 2021

Songsupap, T, Newton, RU, and Lawsirirat, C. Balancing injury risk and power development by weighted jump squat through controlling eccentric loading. J Strength Cond Res 35(11): 2999–3005, 2021—Weighted jump squat (WJS) training is highly effective for increasing neuromuscular power but entails higher injury risk than traditional resistance training because of the impact of landing. Braking mechanisms can be used to control the landing impact; however, the optimal eccentric loading condition that balances injury risks and power output is still unclear. The purpose of this study was to assess different eccentric braking conditions. Twenty-two male varsity basketball players aged 20.8 ± 1.1 years and a 1 repetition maximum (1RM) of back squat-to-body mass ratio of 2.0 ± 0.2 participated in the study. The subjects performed 2 sets of WJS of 6 repetitions with additional 30% of 1RM load under 4 randomly assigned conditions: (a) traditional load, no braking (B0), (b) 25% braking load reduction during landing (B25), (c) 50% braking load reduction during landing (B50), and (d) 100% braking load reduction during landing with release at touchdown (B100R). A repeated measures analysis of variance was used to determine differences of dependent variables: peak power output, peak force, peak velocity, and impulse. B100R resulted in statistically lower eccentric peak force and impulse for the first 50 milliseconds than the other 3 conditions (p < 0.05), but the largest concentric peak power. Furthermore, B0 resulted in statistically lower concentric peak power and peak velocity than the other 3 conditions (p < 0.05). We suggest that B100R was a more favorable loading condition that balanced injury risk and power production in WJS.
Acute Inflammatory, Anthropometric, and Perceptual (Muscle Soreness) Effects of Postresistance Exercise Water Immersion in Junior International and Subelite Male Volleyball Athletes
Authors: Horgan Barry G. , West Nicholas P. , Tee Nicolin , Drinkwater Eric J. , Halson Shona L. , Vider Jelena , Fonda Christopher J. , Haff G. Gregory , Chapman Dale W.
Published: September 2021

Horgan, BG, West, NP, Tee, N, Drinkwater, EJ, Halson, SL, Vider, J, Fonda, CJ, Haff, GG, and Chapman, DW. Acute inflammatory, anthropometric, and perceptual (muscle soreness) effects of postresistance exercise water immersion in junior international and subelite male volleyball athletes. J Strength Cond Res 36(12): 3473–3484, 2022—Athletes use water immersion strategies to recover from training and competition. This study investigated the acute effects of postexercise water immersion after resistance exercise. Eighteen elite and subelite male volleyball athletes participated in an intervention using a randomized cross-over design. On separate occasions after resistance exercise, subjects completed 1 of 4 15-minute interventions: control (CON), cold water immersion (CWI), contrast water therapy (CWT), or hot water immersion (HWI). Significance was accepted at p ≤ 0.05. Resistance exercise induced significant temporal changes (time effect) for inflammatory, anthropometric, perceptual, and performance measures. Serum creatine kinase was reduced (g = 0.02–0.30) after CWI (p = 0.007), CWT (p = 0.006), or HWI (p < 0.001) vs. CON, whereas it increased significantly (g = 0.50) after CWI vs. HWI. Contrast water therapy resulted in significantly higher (g = 0.56) interleukin-6 concentrations vs. HWI. Thigh girth increased (g = 0.06–0.16) after CWI vs. CON (p = 0.013) and HWI (p < 0.001) and between CWT vs. HWI (p = 0.050). Similarly, calf girth increased (g = 0.01–0.12) after CWI vs. CON (p = 0.039) and CWT (p = 0.018), and HWI vs. CON (p = 0.041) and CWT (p = 0.018). Subject belief in a postexercise intervention strategy was associated with HSP72 (“believer”>“nonbeliever,” p = 0.026), muscle soreness (“believer”>“nonbeliever,” p = 0.002), and interleukin-4 (“nonbeliever”>“believer,” p = 0.002). There were no significant treatment × time (interaction effect) pairwise comparisons. Choice of postexercise water immersion strategy (i.e., cold, contrast, or hot) combined with a belief in the efficacy of that strategy to enhance recovery or performance improves biological and perceptual markers of muscle damage and soreness. On same or subsequent days where resistance exercise bouts are performed, practitioners should consider athlete beliefs when prescribing postexercise water immersion, to reduce muscle soreness.
Leaning the Trunk Forward Decreases Patellofemoral Joint Loading During Uneven Running
Authors: AminiAghdam Soran , Epro Gaspar , James Darren , Karamanidis Kiros
Published: September 2021

AminiAghdam, S, Epro, G, James, D, and Karamanidis, K. Leaning the trunk forward decreases patellofemoral joint loading during uneven running. J Strength Cond Res 36(12): 3345–3351, 2022—Although decline surfaces or a more upright trunk posture during running increase the patellofemoral joint (PFJ) contact force and stress, less is known about these kinetic parameters under simultaneous changes to the running posture and surface height. This study aimed to investigate the interaction between Step (10-cm drop-step and level step) and Posture (trunk angle from the vertical: self-selected, ∼15°; backward, ∼0°; forward, ∼25°) on PFJ kinetics (primary outcomes) and knee kinematics and kinetics as well as hip and ankle kinetics (secondary outcomes) in 12 runners at 3.5 ms−1. Two-way repeated measures analyses of variance (α = 0.05) revealed no step-related changes in peak PFJ kinetics across running postures; however, a decreased peak knee flexion angle and increased joint stiffness in the drop-step only during backward trunk-leaning. The Step main effect revealed significantly increased peak hip and ankle extension moments in the drop-step, signifying pronounced mechanical demands on these joints. The Posture main effect revealed significantly higher and lower PFJ kinetics during backward and forward trunk-leaning, respectively, when compared with the self-selected condition. Forward trunk-leaning yielded significantly lower peak knee extension moments and higher hip extension moments, whereas the opposite effects occurred with backward trunk-leaning. Overall, changes to the running posture, but not to the running surface height, influenced the PFJ kinetics. In line with the previously reported efficacy of forward trunk-leaning in mitigating PFJ stress while even or decline running, this technique, through a distal-to-proximal joint load redistribution, also seems effective during running on surfaces with height perturbations.
Cross-Sectional Study of the Physical Fitness and Anthropometric Profiles of Adolescent Hurling, Camogie, and Gaelic Football Players
Authors: Byrne Louise M. , Byrne Paul J. , Byrne Emma K. , Byrne Aaron P. , Coyle Colin
Published: September 2021

Byrne, LM, Byrne, PJ, Byrne, EK, Byrne, AP, and Coyle, C. Cross-sectional study of the physical fitness and anthropometric profiles of adolescent hurling, camogie, and Gaelic football players. J Strength Cond Res 36(12): 3422–3431, 2022—The primary aim of this study was to identify the physical fitness profile of Irish adolescents playing hurling, camogie, and Gaelic football according to age and gender. To establish relationships between the physical fitness tests and anthropometry for these male and female adolescents. This cross-sectional study design included 311 adolescents between age of 13–18 years. Subjects completed a physical fitness test battery of 9 tests which included the following: height, body mass, modified sit and reach (SR), seated medicine ball throw (MBT), countermovement jump (CMJ), standing long jump (SLJ), 15-m sprint, 505 agility, and a 6-minute modified Cooper test (m-CT). Female subjects scored significantly higher in the SR than males, and older adolescents scored significantly higher than younger adolescents (p < 0.05). In the remaining fitness tests (MBT, SLJ, CMJ, 15-m sprint, agility, and m-CT), males outperformed females, males had greater anthropometry scores than females, and older adolescents outperformed and had higher changes in anthropometry than younger counterparts (p < 0.05). Normative data for gender and age-specific percentile values (5th, 10th, 25th, 50th, 75th, 90th, and 95th) for these tests in these adolescent players are provided. These data are useful for clubs, parents, coaches, clinicians, and secondary schools in monitoring adolescents and to provide training programs that develop athletic performance.
Rapid and Bihemispheric Reorganization of Neuronal Activity in Premotor Cortex after Brain Injury
Authors: Moreau-Debord Ian , Serrano Éléonore , Quessy Stephan , Dancause Numa
Published: September 2021

Brain injuries cause hemodynamic changes in several distant, spared areas from the lesion. Our objective was to better understand the neuronal correlates of this reorganization in awake, behaving female monkeys. We used reversible inactivation techniques to “injure” the primary motor cortex, while continuously recording neuronal activity of the ventral premotor cortex in the two hemispheres, before and after the onset of behavioral impairments. Inactivation rapidly induced profound alterations of neuronal discharges that were heterogeneous within each and across the two hemispheres, occurred during movements of either the affected or nonaffected arm, and varied during different phases of grasping. Our results support that extensive, and much more complex than expected, neuronal reorganization takes place in spared areas of the bihemispheric cortical network involved in the control of hand movements. This broad pattern of reorganization offers potential targets that should be considered for the development of neuromodulation protocols applied early after brain injury.

SIGNIFICANCE STATEMENTIt is well known that brain injuries cause changes in several distant, spared areas of the network, often in the premotor cortex. This reorganization is greater early after the injury and the magnitude of early changes correlates with impairments. However, studies to date have used noninvasive brain imaging approaches or have been conducted in sedated animals. Therefore, we do not know how brain injuries specifically affect the activity of neurons during the generation of movements. Our study clearly shows how a lesion rapidly impacts neurons in the premotor cortex of both hemispheres. A better understanding of these complex changes can help formulate hypotheses for the development of new treatments that specifically target neuronal reorganization induced by lesions in the brain.
Aerodynamic study of three cars in tandem using computational fluid dynamics
Authors: H. Abdul-Rahman  , Moria H. , Mohammad Rasani Mohammad Rasidi
Published: September 2021

Aerodynamics of vehicles account for nearly 80% of fuel losses on the road. Today, the use of the Intelligent Transport System (ITS) allows vehicles to be guided at a distance close to each other and has been shown to help reduce the drag coefficients of the vehicles involved. In this article, the aim is to investigate the effect of distances between a three car platoons, to their drag and lift coefficients, using computational fluid dynamics. To that end, a computational fluid dynamics (CFD) simulation was first performed on a single case and platoon of two Ahmed car models using the STAR-CCM+ software, for validation with previous experimental studies. Significant drop in drag coefficients were observed on platoon models compared to a single model. Comparison between the k-w and k-e turbulence models for a two car platoon found that the k-w model more closely approximate the experimental results with errors of only 8.66% compared to 21.14% by k-e turbulence model. Further studies were undertaken to study the effects of various car gaps (0.5L, 1.0L and 1.5L; L = length of the car) to the aerodynamics of a three-car platoon using CFD simulation. Simulation results show that the lowest drag coefficient that impacts on vehicle fuel savings varies depending on the car's position. For the front car, the lowest drag coefficient (CD) can be seen for car gaps corresponding to X1 = 0.5L and X2 = 0.5L, where CD = 0.1217, while its lift coefficient (CL) was 0.0366 (X1 and X2 denoting first to second and second to third car distance respectively). For the middle car, the lowest drag coefficient occurred when X1 = 1.5L and X2 = 0.5L, which is 0.1397. The lift coefficient for this car was -0.0611. Meanwhile, for the last car, the lowest drag coefficient was observed when X1 = 0.5L and X2 = 1.5L, i.e. CD = 0.263. The lift coefficient for this car was 0.0452. In this study, the lowest drag coefficient yields the lowest lift coefficient. The study also found that for even X1 and X2 spacings, the drag coefficient increased steadily from the front to the last car, while the use of different spacings were found to decrease drag coefficient of the rear car compared to the front car and had a positive impact on platoon driving and fuel-saving.
Numerical studies for effect of geometrical parameters on water jet pump performance via entropy generation analysis
Authors: Helios Muhammad Penta , Asvapoositkul Wanchai
Published: September 2021

This paper presented an implementation of entropy generation analysis in the main flow field of a water jet pump via the CFD method. This study aimed to identify the inefficient location of energy conversion and to analyse entropy generation sources in each region of the water jet pump. The 2D-axisymmetric model and realisable k-ε (RKE) turbulence model at steady-state conditions were performed to validate jet pump performance and to assess the entropy generation. Likewise, the effects of the projection ratio  and throat-aspect ratio as independent parameters were investigated. As a result, the throat is the most inefficient part due to the high total entropy generation rate, following by diffuser part. Also, the entropy generation rate was assessed dominant than viscous dissipation due to the turbulent dissipation, which was caused by a turbulent shear stress layer of mixing the streams. In conclusion, the projection ratio influenced the growth of the shear stress layer as well as the entropy generation. Further, the throat-aspect ratio affected the distribution of entropy generation in the throat section. An appropriate combination of both parameters has an impact on the jet pump performance improvements reducing the entropy generation rate in the future.
Study on Lubrication Efficiency and Friction Power Loss of Engine Based on a Hybrid Hydrodynamic Model
Authors: Jiao Renqing , Nguyen Vanliem
Published: September 2021

Friction loss is one of the main factors affecting engine power. Reducing friction power losses to improve the power of engines is a significant concern for designers. Especially, under the background of energy-saving and emission reduction, it is indispensable to carry out an in-depth investigation on engine bearing lubrication characteristics. Unlike the previous studies of separate modelling, a new modelling method of coupling the dynamic and lubrication model is proposed in this paper. The bearing capacity, friction force, friction coefficient and eccentricity ratio were taken as the evaluation criterion, and the influence of design parameters such as angular speed, bearing radius and width on the lubrication efficiency and friction power loss (LE-FPL) were studied. The results indicate that increasing the angular speed, bearing radius or width can effectively reduce the eccentricity ratio and raise the minimum oil film thickness, which is beneficial to improve the lubrication efficiency. However, the above methods to improve engine lubrication efficiency will lead to more power loss of engine to a certain extent. Therefore, studies on reducing the friction power loss for the engine and on improving the lubrication efficiency for the engine should be considered coordinately in the dynamic design and optimisation of the engine.
Numerical Prediction of Creep Rupture Life of Ex-Service and As-Received Grade 91 Steel at 873 K
Authors: FERDOUS IMAM UL , ALANG NASRUL AZUAN , Alias Juliawati , Nadzir Suraya Mohd
Published: September 2021

Infallible creep rupture life prediction of high  temperature steel needs long hours of robust  testing over a domain of stress and temperature. A substantial amount of effort has been made to  develop alternative methods to reduce the time  and cost of testing. This study presents a finite  element analysis coupled with a ductility based  damage model to predict creep rupture time  under the influence of multiaxial stress state of  ex-service and as-received Grade 91 steel at 873 K. Three notched bar samples with different  acuity ratios of 2.28, 3.0 and 4.56 are modelled in commercial Finite Element (FE) software,  ABAQUS v6.14 in order to induce different stress  state levels at notch throat area and investigate  its effect on rupture time. The strain-based  ductility exhaustion damage approach is  employed to quantify the damage state. The  multiaxial ductility of the material that is  required to determine the damage state is  estimated using triaxiality-ductility Cock and  Ashby relation. Further reduction of the ductility  due to the different creep mechanisms over a  short and long time is also accounted for in the  prediction. To simulate the different material conditions: ex-service and as-received material,  different creep coefficients (A) have been  assigned in the numerical modelling. In the case  of ex-service material, using mean best fit data  of minimum creep strain rate gives a good life  prediction, while for new material, the lower  bound creep coefficient should be employed to  yield a comparable result with experimental  data. It is also notable that ex-service material  deforms faster than as-received material at the  same stress level. Moreover, higher acuity  provokes damage to concentrate on the small  area around the notch, which initiates higher  rupture life expectancy. It also found out that,  the stress triaxiality and the equivalent creep  strain influence the location of damage initiation  around the notch area.
Drag Reduction by Application of Different Shape Designs in a Sport Utility Vehicle
Authors: Elsayed Omer , Omar Ashraf A. , Jeddi Ali , EL HESSNI Saad , Hachimy Fatima Zahra
Published: September 2021

Road vehicles drag is a direct consequence of a  large wake area generated behind. This area is  created owing to the vehicle shape, which is  determined by the class, functional and aesthetic  of the vehicle. Aerodynamic  characteristics are a ramification and not the  reason for the vehicle architecture. To enhance  pressure recovery in the wake region, hence  reduce drag, three different passive flow control  techniques were applied to sport-utility-vehicle  (SUV). A three-dimensional SUV was designed in  CATIA, and a numerical flow simulation was  conducted using Ansys-Fluent to evaluate the  aerodynamic effectiveness of the proposed flow  control approaches. A closed rectangular flap as  an add-on device modifies the wake vortex  system topology, enhances vortex merging, and  increases base pressure which leads to a drag  reduction of 15.87%. The perforated roof surface  layer was used to delay flow separation. The  measured base pressure values indicate a  higher-pressure recovery, which globally  reflected in a drag reduction of 19.82%. Finally,  air guided through side rams was used as steady  blowing. A steady passive air jet introduced at the core of the longitudinal trailing  vortices leads to a confined wake area.  The net effects appear in a global increase in the  base pressure values and the pronounced drag  reduction of 22.67%.
Numerical Analysis of Thick Isotropic and Transversely Isotropic Plates in Bending using FE Based New Inverse Shear Deformation Theory
Authors: BHASKAR DHIRAJ , G. Thakur Ajaykumar , I. Sayyad Imran , V. Bhaskar Santosh
Published: September 2021

In this work, using new inverse trigonometric kinematic displacement function, the bending solution of simply supported isotropic and transversely isotopic thin, moderately thin and thick square plates with aspect ratio variations is given. The paper introduces a new inverse trigonometric shear deformation theory (nITSDT) for the bi-directional bending study, which is variationally compatible. The transverse shear stress can be obtained directly from the constitutive relationships on the top and bottom surfaces of the plate that satisfy the shear stress free surface conditions, so the theory does not need a factor for shear correction. The dynamic version of the virtual work principle is used to obtain the governing equations and boundary conditions of the theory. The Finite Element (FE) solution has been developed using MATLAB code based on the present theory for simply supported laminated composite plates. In order to illustrate the efficiency of the proposed theory, the results of displacements and stresses are compared with those of other refined theories and exact solution. The findings obtained from the use of the theory are found to agree well with the precise results of elasticity.
SMED Simulation in Optimising the Operating Output of Tandem Press Line in the Automotive Industry using WITNESS Software
Authors: Basri A.Q. , Nik Mohamed Hj Nik Mohd Zuki , . Nelfiyanti , Y. Yusoof
Published: September 2021

The automotive industry is one of the most advanced industries in the world. The demand for vehicles keeps increasing over time, mainly influenced by technology’s sophistication and impressive designs. This research is focusing on the production performance of the stamping process in Malaysia’s automotive industry. The main issue observed and evidenced in data collected from industry players is that an unacceptably long time is taken in the die/tooling change process, which grossly affects the planned production output. The most significant direct impact on this situation is the increase in operating costs due to additional time taken to meet the planned production output. Therefore, this research aims to establish a new framework that can optimise the efficiency of the dies changeover process, which could lower the overall production cost, which could partially transfer the saving to the consumers. The study was conducted in two stages; the first is on data collection correlates with the automotive stamping premise to create a simulation procedure, and the second is to analyse the current production output using WITNESS simulation. These simulated output data have later been compared to the actual industrial data. Using a systematic dies changeover process, a new alternative framework was proposed. The framework combined single minute exchange of die (SMED), lean tools and simulation to become an integrated single minute exchange of die (ISMED). It shows that the proposed method decreased the changeovers processes from the initial of 1509.5 seconds to 750.75 seconds, then further reduced to 569.75 seconds, with the nett time reduction of 62.2%. The result shows that the daily production output has increased gradually from 1100 pieces to 1500 pieces, further increasing to 2145 pieces. As evidenced in analytical data, it is believed that this new framework can strengthen the total output in the manufacturing process, especially in the manufacturing of automotive stamping parts.
A CFD Analysis on the Influence of Upstream Surface Geometry Modifications of Clerestory Shaped Rib on Heat Transfer Characteristics of Solar Air Heater
Authors: Fernandes Dr. Dolfred Vijay , M.S. Manjunath
Published: September 2021

Two-dimensional numerical analysis is conducted to determine the influence of upstream surface modifications of a novel clerestory shaped rib turbulator on thermal performance augmentation. The upstream surface of the rib is divided into two parts where the upper rib surface is always normal to the incoming flow and the lower rib surface, which is inclined to the flow. The elevation of the vertical surface is varied using non-dimensional approach length (h/e=0, 0.25, 0.5 and 0.75), and the inclination of the lower surface is varied using the rib angle (θ=15°, 45° and 90°). The relative roughness height and pitch of rib is fixed as 0.0421 and 12.5, respectively. RNG k-ϵ turbulence model is used in the analysis, and Reynolds number is varied from 8000-20000. The results reveal that the combined effect of flow impingement and the suppression of formation of recirculation zone leads to increased heat transfer. Lower values of non-dimensional approach length and rib angle provides a higher thermal enhancement factor. The highest increase in Nusselt number is found to be about 1.82 times that of the smooth duct at Re=8000 for h/e=0.25 and rib angle of 15°. The maximum thermal enhancement factor is found to have a range of 1.6-1.45 for an approach length of 0.25 and a rib angle of 15°.
Holes' Parameters Analysis of a Perforated Thin-Walled Lipped Beam Buckled Under a Bending Load
Authors: Khazaal D.S. , Al-Khafaji Hussein M. H. , Abdulsahib I.A.
Published: September 2021

This work studied the effects of holes on the buckling characteristic of an open thin-walled lipped channel beam under a bending load. A nonlinear finite element method was utilised to examine the buckling behaviour of the beam. Experimental works were carried out to verify the finite element simulation. Three factors were chosen to examine their influence on the buckling of the beam. These factors namely, the holes’ shape, perforated ratio (hole length to beam height) and spacing ratio (centre to centre distance between holes to beam height). The finite elements output was analysed by implementing the Taguchi method to distinguish the best group of three parameters collections for optimal strength of buckling. Whereas the analysis of variance technique (ANOVA) method was applied to specify the impact of each parameter on critical buckling load. Outcomes showed that the combination of parameters that gives the best buckling strength is the hole with a hexagonal shape, perforated ratio =1.7  and spacing ratio =1.3, and the holes’ shape is the most effective factor. In addition, the study demonstrated that the hole's shape factor has the greatest influence on the buckling capacity. While the perforated ratio factor is the least influential.
Optimal Speed Control Humps Design Based on Driver Comfort
Authors: Gheibollahi Hamid , Masih-Tehrani Masoud
Published: September 2021

The purpose of this study is to optimise the different speed control humps by considering the vertical and horizontal acceleration of the driver’s head. In previous researches, the main focus was only on vertical acceleration, but in this study, horizontal acceleration of the head is also considered. Here, the root mean square (RMS) of acceleration of head is considered as a measure of occupant comfort. The modelling is performed by a non-linear half-car suspension system (4-DOF) with a linear model of a driver (10-DOF) and a seat. The hamps under study are circular, sinusoidal, half-sinusoidal, and trapezoidal. Finally, by analysing the results, the optimal design of each type of hump is performed. The objective function used is a combination of horizontal and vertical acceleration which is performed using MATLAB genetic algorithm. The results show a significant reduction in horizontal and vertical acceleration at all speeds. From this modelling, it is possible to extract a suitable range for passing the speed of cars over different types of humps. In this study, it is shown that the acceleration values for the circular and half-sinusoidal humps at all speeds are quite close to each other.
Fabrication and Modelling of Tribological Performance of Al-Si/12Al2O3/2MoS2 Composite using Taguchi Technique
Authors: VUDDAGIRI HARI KIRAN , Vadapalli Srinivas , Sagari Jaikumar , R. Sivasankara Raju
Published: September 2021

This paper investigates the effect of mechanical, microstructural and dry sliding wear behaviour of Al-Si/2wt%MoS2, Al-Si/12wt%Al2O3, and Al-Si/12wt% Al2O3/2wt%MoS2 composites that prepared using the stir-casting route. To avoid friction and wear at the interfaces of materials, an attempt has been made by adding solid lubricant MoS2 to build such a self-lubricating composite with Al-matrix. The tribological analysis has been described based on the Taguchi orthogonal array (L27). Three variables combination such as sliding velocity, sliding distance and contact pressure are used for this study to determine the tribological responses, i.e. wear rate and coefficient of friction. The properties of composites were improved by increasing the weight % of MoS2 and Al2O3. The tensile strength of Al-Si/2MoS2, Al-Si/12Al2O3, and Al-Si/12 Al2O3/2MoS2 composites is 6.02%, 12.46%, and 2.44% compared to the base matrix. The addition of MoS2 helps the hybrid composite to attain better tribological properties with a slightly lower specific strength. Analysis of variance showed that the composites such as Al-Si/2 MoS2 and Al-Si/12Al2O3/2MoS2 were strongly influenced by the pressure in wear rate. Similarly, sliding velocity affects the coefficient of friction for Al-Si/2MoS2. Wear tracks formed during the dry slide process were analysed using optical and SEM with an EDS. It was discovered that pressure plays a vital effect in the wear mechanism. The hybrid composite (Al-Si/12 Al2O3/2MoS2) material can be utilised in place of conventional materials in tribological demanding automotive applications
Statistical Analysis of Tribological Performance of Functionally Graded Copper Composite Using DOE
Authors: N. Radhika , Sam M.
Published: September 2021

Dry sliding performance of Cu-11Ni-4Si/10wt.%Al2O3 graded composite was investigated statistically and experimentally using pin-on-disc wear tester. Microstructural analysis revealed maximum gradient concentration of ceramics towards the inner radial wall of developed composite. The wear analysis was based on Taguchi’s L27 orthogonal array and Regression models, at tribo-parameters (load-15, 25, 35 N, slide velocity-1.5, 2.5, 3.5 m/s and slide distance-750, 1500, 1250 m). Wear raised with proportional rise in load and distance. Trend analysis of influential factors against wear response was studied using Analysis of Variance. The influence of process conditions and their interactions on the wear are also detailed. Worn surface analysis identified the formation of Mechanically Mixed Layers at intermediate velocity. This had a major influence over the improvement of wear resistance. This developed composite is suggestable for diverse automobile components of various tribology applications.
Effect of Nitromethane and Jatropha Biodiesel on the Combustion, Performance and Emission Characteristics of Diesel Engine
Authors: Valipour Berenjestanaki Alireza , Hussain Dilawar
Published: September 2021

The experimental work reported has been carried out in two parts; Jatropha biodiesel production and engine test. The engine test has been carried out on a direct injection, single-cylinder, water-cooled stationary diesel engine. Several diesel fuel blends which contain 10% and 20% by volume of JBD and 1% and 3% nitromethane were prepared. The effects of these blends on the combustion, performance, and emission characteristics of diesel engine were studied. The tests were performed under constant speed and varying load conditions without altering injection timing. A maximum increase of 11.73%, 3.2 % and 7.68 % in the brake thermal efficiency, the brake specific fuel consumption and exhaust gas temperature were achieved respectively for 20% Jatropha biodiesel and 3% nitromethane at full engine load. Compared to the pure diesel operation, the peak in-cylinder pressure of blended fuels was lower at the full load conditions. Also, the maximum net heat release rate of blended fuels was lower than that of diesel at all loading conditions. In regards to the engine emissions, the results showed that the blended fuels reduced carbon monoxide at 18.6–28.9% and unburned hydrocarbon of 7.5-24.2%, while increased the emission of nitrogen oxides at 6.9–14.3% and carbon dioxide at 4.3-10.5%.
Manufacturing of Polymer-based 1×2 Y-branch Symmetric and Asymmetric Waveguide Coupler through Moulding Technique
Authors: Ghazali Mohd Shafiq , Mohd Romlay Fadhlur Rahman , Ehsan Abang Annuar
Published: September 2021

Manufacturing of Y-branch coupler depends on high technology production equipment and in-factory accuracy assembly tools. The manufacturing of a 1×2 Y-branch symmetric and asymmetric waveguide coupler based on the mould replication process and Epoxy OG142 as an optical core is presented; an alternative to provide a less complex technique. The polymer optical waveguide adopted two basic designs: the 1×2 Y-branch symmetric coupler as the core structure and the 1×2 asymmetric coupler that allows non-symmetric optical splitting. This paper focused on the main structure fabrication of the 1×2 symmetric and asymmetric waveguide coupler that produces a power output. The fabrication was done by engraving acrylic to produce a master mould using CNC machining tools for optical devices. Both 1×2 devices were made via soft lithography, which duplicated the pattern from the master mould onto a second mould to produce an actual device. Optical polymer epoxy OG142 was injected into the second mould, of which the product was then put on top of acrylic. The device was completed after curing the optical polymer glue, epoxy OG142, by exposing the assembly on the second mould under UV light until both parts bonded. The difference between the simulation and design TOFR value was only ±2%. This showed that the simulation and design are in good agreement, which provides similar performance.
Effects of Post-Injection Characteristics on the Combustion, Emission, and Performance in a Diesel-Syngas Reactivity Controlled Compression Ignition Engine
Authors: Noroozi M. J. , Seddiq M.
Published: September 2021

This paper presents a numerical investigation of the separate effects of post-injection characteristics in a heavy-duty turbocharged direct injection diesel engine under pure diesel combustion (PDC) and diesel-syngas combustion (DSC) operating conditions. Converge CFD code was used coupled with a detailed n-heptane/toluene/PAH chemical kinetic mechanism (consists of 71 species and 360 reactions) for diesel-syngas dual-fuel combustion simulation. A total of 36 strategies based on the post-injection characteristics (post-injection timing, fuel quantity, spraying pressure, and main-post dwell time) on the combustion characteristics, exhaust gas emissions, and engine performance under PDC and DSC conditions were investigated. Numerical achievements revealed that 40% substitution of diesel fuel with syngas significantly decreased particulate matter emission and enhanced the indicated thermal efficiency (ITE), compared to the baseline PDC case. However, carbon monoxide noticeably increased. In addition, retarding the post-injection timing prolonged the combustion duration and also reduced the nitrogen oxides emissions and ITE. By increasing the post-injection quantity up to 15%, the combustion process deteriorated, and carbon-based emissions such as particulate matter, carbon monoxide, and unburnt hydro-carbon in the exhaust gases increased under PDC and DSC conditions. Furthermore, increasing post-injection pressure (PIP) from 1000 to 1450 bar under both PDC and DSC conditions led to higher flame temperature, and as a result, the heat release rate peak point and temperature peak point for the second combustion event increased. However, at a PIP of 1600 bar, the ITE deteriorated under PDC and DSC operating cases.
Biomimetic Designs for Automobile Engineering: A Review
Authors: Wijegunawardana I. D. , De Mel W.R.
Published: September 2021

Automobile engineering often demands creative and innovative concepts to achieve their performance and efficiency targets. However, the strategies used to create these concepts are evolving with time. Recently, heightened attention has been noticed to using biomimetic concepts in the field of automobile design. The studies that apply biomimicry to automobile design often exhibit improvements in vehicle performance and fuel efficiency. Consequently, biomimetic concepts have extended an opportunity to the automobile industry to generate futuristic designs with advanced technology. However, the innovations and inventions in biology are usually published with more complex terminology that is not convenient for the research community working on automobile engineering. Hence, a notable delay is present in transferring the recent discoveries in biology to engineering researches so that they can develop strategies to mimic them. The purpose of this paper is to provide a brief overview of the biomimetic design approaches that have been and can be used in automobile design. In addition, the paper includes a classification of biomimetic concepts, which reveals the current research interests and highlights the areas with a deficit of research that is required to be addressed extensively in the future.
Suitability Analysis of Solar Tracking PV System in the Airport Based on Glare Assessment
Authors: Sreenath S. , Sudhakar K. , Yusop A.F.
Published: September 2021

Due to the concerns with harmful emissions, airports have a great interest in solar photovoltaic technology. On the one hand, the vacant land areas in the airport can house solar PV arrays. On the other hand, there is an aviation safety issue due to the reflections from the solar PV arrays. This paper aims to perform a glare analysis of a conceptual solar PV array for three different solar tracking techniques. This suitability analysis is carried out for fixed-tilt, single-axis and dual-axis tracking techniques using ForgeSolar software. It is observed that a single-axis tracking solar PV system is a suitable tracking technique for the selected site. This can be attributed to zero minutes of glare duration and the highest value of energy generation. In addition to compliance with the FAA’s solar glare policy, the single-axis tracking solar PV system will generate 40 % more electricity than a fixed-tilt solar PV system. Unlike previously reported studies, the results of this study strengthen the theoretical support for tracking solar PV systems in airport locations. The findings provided in this study will be beneficial to energy professionals and serve as reference material for tracking solar PV in airports.
Performance characteristics of diesel engine using blends of Jatropha biodiesel
Authors: Mahmood Tariq , Khan Zain Ali , Hassan Shahid , Chaudhry Ijaz A.
Published: September 2021

Jatropha is a tropical herb and can be matured in a diverse soil with low to high rainfall. It provides a chunk of the fuel supply in the transportation and energy sectors. Jatropha biodiesel implies a diesel equivalent and consist of methyl esters. It is produced through the transesterification process which is a chemical reaction of jatropha oil with an alcohol in the presence of a catalyst. In the present work, the physical and chemical attributes of jatropha biodiesel were determined. Various blended samples of jatropha biodiesel with mineral diesel were used to run diesel engine to see the variation of the brake power, brake specific fuel consumption and brake thermal efficiency of engine with percentage increase of jatropha biodiesel in the mixture. It was observed that these properties remain unchanged for 5% and 10% blend of jatropha biodiesel to mineral diesel and hence its use is quite feasible without any change in engine design. This provides an edge to the countries having surplus lands in low rain areas to generate 10% of their energy resources for power generation and transport through the cultivation and growth of jatropha plants.
Simulation of bypass electric water pump to reduce the engine warm-up time
Authors: Abdul Jalal Rifqi Irzuan , Mohd Yusoff M.A , Abid Hasan H.M , Yahya M.N
Published: September 2021

There are several strategies have been developed in the automotive cooling system to improve engine thermal management. Basically, these designs use controllable actuators and mechatronic components such as electric water pump, controllable thermostat, and controllable electric fan to improve engine temperature control on most operating ranges. Most of the strategies are complicated and costly. This paper introduced a different approach to improve coolant temperature warm-up during cold start. The new strategy was by promoting a higher coolant flow rate inside the engine block by just installing an electric water pump in the bypass hose. The new approach’s cold start performance was studied using GT-SUITE on a transient model, complete with finite-element of engine block design, lubrication system, components friction model, engine with combustion model and vehicle system. The proposed strategy clearly showed faster coolant temperature increase (18 seconds faster compared to the conventional cooling system). The strategy not only increase the coolant temperature faster, but also increases the oil temperature faster, lower Friction Mean Effective Pressure (FMEP), and lower fuel consumption at certain condition during the warm-up period.
Three-dimensional fluid-thermal-structure multiphysics interaction simulation model of aluminium extrusion process
Authors: Al-Baghdadi Maher A. R. Sadiq , Al-Waily Muhannad
Published: September 2021

Three dimensional fluid-thermal-structure multiphysics interaction simulation model of aluminium extrusion process has been simulated and presented in this paper. This multiphysics complex geometrical engineering process is simulated effectively using computational fluid dynamics (CFD) simulation with very high accuracy, where the aluminium material is treated as a fluid that has a very high viscosity which depends on temperature and velocity. When aluminium moving, the inner friction will work as a heat source, therefore the model of the heat transfer is completely coupled together with those governing model of the fluid dynamics. Material properties come into a viscosity function that can be related to the flow stress locally depending on forming velocity and temperature. In addition, the stresses distribution in the die that introduces due to the fluid pressure and the thermal loads has been modelled by fully coupled the simulation model with the structural mechanic's analysis. Fully three-dimensional results during the process of the temperature distribution, velocity profile, von Mises stress distribution, total displacement and deflection distribution, equivalent volumetric strain distribution, and pressure distribution are presented and analysed with a focus on the fundamental understanding. The model is shown to be able to provide a computer-aided design tool for optimize this complex engineering process by improving productivity and reducing scrap.
Thermodynamic investigation of intercooling location effect on supercritical CO2 recompression Brayton cycle
Authors: Jarungthammachote Sompop
Published: September 2021

In S-CO2 recompression Brayton cycle, use of intercooling is a way to improve the cycle efficiency. However, it may decrease the efficiency due to increase of heat rejection. In this work, two S-CO2 recompression Brayton cycles are investigated using the thermodynamic model. The first cycle has intercoolings in a main compression and a recompression process (MCRCIC) and the second cycle has an intercooling in only the recompression process (RCIC). The thermal efficiencies of both cycles are compared with that of S-CO2 recompression Brayton cycle with intercooling in the main compression process (MCIC). Effects of a split fraction (SF) and a ratio of pressure ratio of the recompression (RPRRC) on the thermal efficiencies of MCRCIC and RCIC are also studied. The study results show that the intercooling of recompressor in MCRCIC and RCIC can reduce the compression power. However, it also rejects heat from the cycle and this leads to increasing added heat in the heater. The thermal efficiency of MCRCIC and RCIC are, then, lower than that of the MCIC. For the effects of RPRRC and SF to the thermal efficiency of the cycles, in general, when RPRRC increases, the thermal efficiency decreases due to increasing rejected heat. The increase in SF causes increasing thermal efficiency of the cycles and the thermal efficiency, then, decrease when SF is beyond the optimal value.