bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffusion toward non-overlapping partially reactive spherical traps: Fresh insights onto classic problems
Authors: Grebenkov Denis S.
Published: June 2020

Several classic problems for particles diffusing outside an arbitrary configuration of non-overlapping partially reactive spherical traps in three dimensions are revisited. For this purpose, we describe the generalized method of separation of variables for solving boundary value problems of the associated modified Helmholtz equation. In particular, we derive a semi-analytical solution for the Green function that is the key ingredient to determine various diffusion–reaction characteristics such as the survival probability, the first-passage time distribution, and the reaction rate. We also present modifications of the method to determine numerically or asymptotically the eigenvalues and eigenfunctions of the Laplace operator and the Dirichlet-to-Neumann operator in such perforated domains. Some potential applications in chemical physics and biophysics are discussed, including diffusion-controlled reactions for mortal particles.
The formation mechanism of voids in physical vapor deposited AlN epilayer during high temperature annealing
Authors: Ben Jianwei , Shi Zhiming , Zang Hang , Sun Xiaojuan , Liu Xinke , Lü Wei , Li Dabing
Published: June 2020

The voids will be formed in the physical vapor deposited (PVD)-AlN epilayer after high temperature annealing. In this work, the formation mechanism of voids and its effect on crystal quality are investigated. Based on microstructural analysis and first principles calculations, it is confirmed that (1) the dislocations mainly gather around the voids and the strain status around the voids is similar to other regions in the same PVD-AlN epilayer, (2) the paired dislocations with opposite signs prefer to move closer and react with each other during high temperature annealing, thus contributing to the formation of voids, (3) the voids provide the inner surface for dislocations to terminate, decreasing the density of the threading dislocation propagating to the surface, and (4) the emergence of dislocations is energetically favorable and the energy dropped by 5.93 eV after the two isolated dislocation lines fused into a void by overcoming a barrier of 1.34 eV. The present work is of great significance for improving the quality and performance of AlN materials and devices.
Vanadium gate-controlled Josephson half-wave nanorectifier
Authors: Puglia C. , De Simoni G. , Ligato N. , Giazotto F.
Published: June 2020

Recently, the possibility to tune the critical current of conventional metallic superconductors via electrostatic gating was shown in wires, Josephson weak-links, and superconductor-normal metal–superconductor junctions. Here, we exploit such a technique to demonstrate a gate-controlled vanadium-based Dayem nano-bridge operated as a half-wave rectifier at 3 K. Our devices exploit the gate-driven modulation of the critical current of the Josephson junction and the resulting steep variation of its normal-state resistance, to convert an AC signal applied to the gate electrode into a DC one across the junction. All-metallic superconducting gated rectifiers could provide the enabling technology to realize tunable photon detectors and diodes useful for superconducting electronics circuitry.
Structure, distribution patterns and ecological responses to hydrological changes in benthic macroinvertebrate assemblages in a regulated semi-arid river: baseline for biomonitoring studies
Authors: Leiva Marta , Marchese Mercedes , Diodato Liliana
Published: June 2020

Biological monitoring requires a comprehensive baseline of assemblage distribution patterns and their environmental drivers. In this study we evaluated benthic macroinvertebrates in a regulated river, located in a semi-arid region, which has a seasonal flood pulse and is affected by several anthropogenic pressures. Taxonomic and trophic structures of benthic macroinvertebrate assemblages were analysed in terms of their longitudinal distribution, hydrological regime and environmental factors, including the effects of hydromorphology, riparian land use and water abstraction. Most taxa were generalists and classified in the collector–gatherer functional feeding group. A large taxonomic replacement was associated with hydromorphological characteristics. Local environmental variables were critical for macroinvertebrate assemblages. There was significant temporal variability regarding seasonal flood pulse. Water abstraction for irrigation had a strong effect on assemblage structure. We suggest some challenges and issues for successful implementation of biomonitoring tools in the Dulce River, related primarily to high spatiotemporal variability.
Preparation of Cu–Al–Ni shape memory alloy strips by spray deposition-hot rolling route
Authors: Agrawal Ashish , Vajpai Sanjay Kumar
Published: June 2020

The present work describes the preparation of near-full density Cu–Al–Ni shape memory alloy (SMA) strips via a novel processing route consisting of ‘spray deposition’ of atomised liquid Cu–Al–Ni alloy with a jet of argon gas followed by hot-rolling densification of the deposited preform. The subsequent homogenisation of the hot rolled Cu–Al–Ni strips resulted in complete martensitic structure in the finished strip, consisting of self-accommodated plates of β1′ and γ1′ martensites. The characteristic transformation temperatures and shape memory effects of Cu–Al–Ni strips were studied. It has been demonstrated that the Cu–Al–Ni SMA strips, prepared in the present work, resulted in relatively finer grain size with better combination of strength and ductility compared to other techniques based on conventional casting method.
Potential Pitfalls of Applying a Therapeutic Logic in Mental Health Law Proceedings
Authors: Pedersen Sven H. , Nilsson Thomas , Eriksson Lena
Published: June 2020

This paper presents an in-depth interview study with individuals who are at the same time patients in forensic psychiatric services, and parties in recurring mental health law proceedings (MHLPs). While previous studies have highlighted issues with the rule of law that can arise when MHLPs prioritize concern for the mental health of the patient over the stringent test of the legal rights of the party, this paper seeks to bring to the fore the potential pitfalls it presents in terms of distress to patients. Drawing on qualitative interview analyses, we untangle the apparent paradox of MHLPs being described in the literature as both guided by concern for patients’/parties’ mental well-being and as distressing. We tentatively raise the question of whether MHLPs might risk being distressing to the patient/party, not despite of but in part because of court actors’ efforts to the contrary.
E1784K, the most common Brugada syndrome and long-QT syndrome type 3 mutant, disrupts sodium channel inactivation through two separate mechanisms
Authors: Peters Colin H. , Watkins Abeline R. , Poirier Olivia L. , Ruben Peter C.
Published: June 2020

Inheritable and de novo variants in the cardiac voltage-gated sodium channel, Nav1.5, are responsible for both long-QT syndrome type 3 (LQT3) and Brugada syndrome type 1 (BrS1). Interestingly, a subset of Nav1.5 variants can cause both LQT3 and BrS1. Many of these variants are found in channel structures that form the channel fast inactivation machinery, altering the rate, voltage dependence, and completeness of the fast inactivation process. We used a series of mutants at position 1784 to show that the most common inheritable Nav1.5 variant, E1784K, alters fast inactivation through two separable mechanisms: (1) a charge-dependent interaction that increases the noninactivating current characteristic of E1784K; and (2) a hyperpolarized voltage dependence and accelerated rate of fast inactivation that decreases the peak sodium current. Using a homology model built on the NavPaS structure, we find that the charge-dependent interaction is between E1784 and K1493 in the DIII–DIV linker of the channel, five residues downstream of the putative inactivation gate. This interaction can be disrupted by a positive charge at position 1784 and rescued with the K1493E/E1784K double mutant that abolishes the noninactivating current. However, the double mutant does not restore either the voltage dependence or rates of fast inactivation. Conversely, a mutant at the bottom of DIVS4, K1641D, causes a hyperpolarizing shift in the voltage dependence of fast inactivation and accelerates the rate of fast inactivation without causing an increase in noninactivating current. These findings provide novel mechanistic insights into how the most common inheritable arrhythmogenic mixed syndrome variant, E1784K, simultaneously decreases transient sodium currents and increases noninactivating currents, leading to both BrS1 and LQT3.
Supplementary pressure comparison from 10 MPa to 100 MPa in hydraulic media at gauge mode
Authors: Durgut Y , Vámossy C , Petrovski N , Kaçarski V , Tomçini B , Djurić P , Vulić A , Al-Jattal N , Justice B K , Alotaibi H M , Alanazi Naif A , Dapkeviciene K , Brzozowski A , Setina J , Bermanec L G , Geel J V , Saxholm S , Altintas A , Bošnjaković A , Ališić  , Hetherington P
Published: June 2020

The regional supplementary comparison EURAMET.M.P-S13 for pressure measurements in liquid media from 10 MPa to 100 MPa was piloted by the TÜBİTAK UME Pressure Laboratory, Turkey. The transfer standard was a digital pressure gauge, serial number 116321, manufactured by Paroscientific Inc. Eighteen laboratories participated in this comparison. Fourteen laboratories are from EURAMET region; namely UME, MKEH, BoM, DPM, DMDM, MBM, GUM, IMT, HMI/FSB-LPM, VSL, VTT MIKES, FORCE Technology, IMBIH, NSAI NML. VMC is from COOMET and QAF, EMI, SASO NMCC are from GULFMET region.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Final report on EURAMET project 1395/EURAMET.M.FF-K4.1.2016: volume comparison at 20 L
Authors: Malengo A , Batista E , Arias R , Mićić L , Bošnjaković A , Mirjana M , Piluri E , Svendsen G K , Huu M de , Sarevska A , Mišovich M , Turnšek U , Xhuraj A , Miteva M , Milkamanavičienė I , Smits E , Terradillos González J Á , Wennergren P , Niessner A , Czibulka C , Benkova M
Published: June 2020

During the EURAMET TC-F annual meeting, held in Boras in 2015, it was agreed to perform the follow up of the CCM.FF-K4.1.2011 organized for the EURAMET NMIs for volume of liquids at 20 L. The transfer standard was a 20 L pipette supplied by CENAM. The participants of this comparison also involved in the comparison CCM.FF-K4.1.2011 were: CENAM, INRIM, IPQ, RISE and VSL, in total there were twenty-one participants. The comparison was organized in two petals, INIRM perform three measurements, at the beginning, after the first petal and at the end of the circulation. The comparison measurements started in April 2016 and ended in October 2017. It should be noted that most of the participants (thirteen) declared an expanded uncertainty less than 0,005 %.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
For physics majors, gender differences in introductory physics do not inform future physics performance
Authors: Whitcomb Kyle M , Singh Chandralekha
Published: June 2020

Analysis of institutional data for physics majors showing predictive relationships between required mathematics and physics courses in various years is important for contemplating how the courses build on each other and whether there is need to make changes to the curriculum for the majors to strengthen these relationships. We used 15 years of institutional data at a US-based large research university to investigate how introductory physics and mathematics courses predict male and female physics majors’ performance on required advanced physics and mathematics courses. We used structure equation modeling (SEM) to investigate these predictive relationships and find that among introductory and advanced physics and mathematics courses, there are gender differences in performance in favor of male students only in the introductory physics courses after controlling for high school GPA. We found that a measurement invariance fully holds in a multi-group SEM by gender, so it was possible to carry out analysis with gender mediated by introductory physics and high school GPA. Moreover, we find that these introductory physics courses that have gender differences do not predict performance in advanced physics courses. In other words, students could be using invalid data about their introductory physics performance to make their decision about whether physics is the right field for them to pursue, and those invalid data in introductory physics favor male students. Also, introductory mathematics courses predict performance in advanced mathematics courses which in turn predict performance in advanced physics courses. Furthermore, apart from the introductory physics courses that do not predict performance in future physics courses, there is a strong predictive relationship between the sophomore, junior and senior level physics courses.
Reference dosimetry in MRI-linacs: evaluation of available protocols and data to establish a Code of Practice
Authors: de Pooter Jacco , Billas Ilias , de Prez Leon , Duane Simon , Kapsch Ralf-Peter , Karger Christian P , van Asselen Bram , Wolthaus Jochem
Published: June 2020

With the rapid increase in clinical treatments with MRI-linacs, a consistent, harmonized and sustainable ground for reference dosimetry in MRI-linacs is needed. Specific for reference dosimetry in MRI-linacs is the presence of a strong magnetic field. Therefore, existing Code of Practices (CoPs) are inadequate. In recent years, a vast amount of papers have been published in relation to this topic. The purpose of this review paper is twofold: to give an overview and evaluate the existing literature for reference dosimetry in MRI-linacs and to discuss whether the literature and datasets are adequate and complete to serve as a basis for the development of a new or to extend existing CoPs.

This review is prefaced with an overview of existing MRI-linac facilities. Then an introduction on the physics of radiation transport in magnetic fields is given. The main part of the review is devoted to the evaluation of the literature with respect to the following subjects:

• beam characteristics of MRI-linac facilities;

• formalisms for reference dosimetry in MRI-linacs;

• characteristics of ionization chambers in the presence of magnetic fields;

• ionization chamber beam quality correction factors; and

• ionization chamber magnetic field correction factors.

The review is completed with a discussion as to whether the existing literature is adequate to serve as basis for a CoP. In addition, it highlights subjects for future research on this topic.
Characterization of a multi-pinhole molecular breast tomosynthesis scanner
Authors: Wang Beien , van Roosmalen Jarno , Kreuger Rob , Huizenga Jan , Beekman Freek J , Goorden Marlies C
Published: June 2020

In recent years, breast imaging using radiolabelled molecules has attracted significant interest. Our group has proposed a multi-pinhole molecular breast tomosynthesis (MP-MBT) scanner to obtain 3D functional molecular breast images at high resolutions. After conducting extensive optimisation studies using simulations, we here present a first prototype of MP-MBT and evaluate its performance using physical phantoms. The MP-MBT design is based on two opposing gamma cameras that can image a lightly compressed pendant breast. Each gamma camera consists of a 250 × 150 mm2 detector equipped with a collimator with multiple pinholes focusing on a line. The NaI(Tl) gamma detector is a customised design with 3.5 mm intrinsic spatial resolution and high spatial linearity near the edges due to a novel light-guide geometry and the use of square PMTs. A volume-of-interest is scanned by translating the collimator and gamma detector together in a sequence that optimises count yield from the scan region. Derenzo phantom images showed that the system can reach 3.5 mm resolution for a clinically realistic 99mTc activity concentration in an 11-minute scan, while in breast phantoms the smallest spheres visible were 6 mm in diameter for the same scan time. To conclude, the experimental results of the novel MP-MBT scanner showed that the setup had sub-centimetre breast tumour detection capability which might facilitate 3D molecular breast cancer imaging in the future.
Novel vertical power MOSFET with partial GaN/Si heterojunction to improve breakdown voltage by breakdown point transfer terminal technology
Authors: Wang Xiameng , Duan Baoxing , Yang Xin , Yang Yintang
Published: June 2020

In this paper, the vertical power MOSFET with partial GaN/Si heterojunction is proposed, and the partial GaN/Si heterojunction double-diffused MOSFET (partial GaN/Si VDMOS) and U-shaped MOSFET (partial GaN/Si UMOS) are simulated. Thanks to the breakdown point transfer technology, the breakdown point is transferred from the high electric field area to the low electric field area, therefore, the breakdown voltage (BV) is improved. Different types of dangling bonds are introduced to simulate the influence of different interface state densities on the forward characteristics of the device, the proposed structure alleviates the influence of interface state occurring in the whole GaN/Si heterojunction VDMOS and UMOS (GaN/Si VDMOS and GaN/Si UMOS). The results show that the BV and the specific on-resistance of partial GaN/Si VDMOS are 325 V and 10.17 mΩ cm2, and of partial GaN/Si UMOS are 279 V and 2.34 mΩ cm2, all of which break the limit relation of silicon.
Pair correlations in the normal phase of an attractive Fermi gas
Authors: Pini M , Pieri P , Jäger M , Denschlag J Hecker , Strinati G Calvanese
Published: June 2020

In a recent paper (2019 Phys. Rev. A
99, 053617), the total number of fermion pairs in a spin-balanced two-component Fermi gas of 6Li atoms was experimentally probed in the normal phase above the superfluid critical temperature, in order to investigate the sectors of pseudogap and preformed-pair in the temperature–coupling phase diagram. Here, we present a theoretical account of these experimental results in terms of an ab initio self-consistent t-matrix calculation, which emphasizes the role of the pair-correlation function between opposite-spin fermions at equilibrium. Good agreement is found between the available experimental data and the theoretical results obtained with no adjustable parameter.
Flagellar length control in biflagellate eukaryotes: time-of-flight, shared pool, train traffic and cooperative phenomena
Authors: Patra Swayamshree , Jülicher Frank , Chowdhury Debashish
Published: June 2020

Flagella of eukaryotic cells are transient long cylindrical protrusions. The proteins needed to form and maintain flagella are synthesized in the cell body and transported to the distal tips. What ‘rulers’ or ‘timers’ a specific type of cells use to strike a balance between the outward and inward transport of materials so as to maintain a particular length of its flagella in the steady state is one of the open questions in cellular self-organization. Even more curious is how the two flagella of biflagellates, like Chlamydomonas reinhardtii, communicate through their base to coordinate their lengths. In this paper we develop a stochastic model for flagellar length control based on a time-of-flight (ToF) mechanism. This ToF mechanism decides whether or not structural proteins are to be loaded onto an intraflagellar transport (IFT) train just before it begins its motorized journey from the base to the tip of the flagellum. Because of the ongoing turnover, the structural proteins released from the flagellar tip are transported back to the cell body also by IFT trains. We represent the traffic of IFT trains as a totally asymmetric simple exclusion process (TASEP). The ToF mechanism for each flagellum, together with the TASEP-based description of the IFT trains, combined with a scenario of sharing of a common pool of flagellar structural proteins in biflagellates, can account for all key features of experimentally known phenomena. These include ciliogenesis, resorption, deflagellation as well as regeneration after selective amputation of one of the two flagella. We also show that the experimental observations of Ishikawa and Marshall are consistent with the ToF mechanism of length control if the effects of the mutual exclusion of the IFT trains captured by the TASEP are taken into account. Moreover, we make new predictions on the flagellar length fluctuations and the role of the common pool.
Entropic time–energy uncertainty relations: an algebraic approach
Authors: Bertoni Christian , Yang Yuxiang , Renes Joseph M
Published: June 2020

We address entropic uncertainty relations between time and energy or, more precisely, between measurements of an observable G and the displacement r of the G-generated evolution e−irG
. We derive lower bounds on the entropic uncertainty in two frequently considered scenarios, which can be illustrated as two different guessing games in which the role of the guessers are fixed or not. In particular, our bound for the first game improves the previous result by Coles et al [Phys. Rev. Lett. 122 100401 (2019)]. To derive our bounds, we extend a recently proposed novel algebraic method by Gao et al [arXiv:1710.10038 [quant-ph]] which was used to derive both strong subadditivity and entropic uncertainty relations for measurements.
A Hybrid Haptic Feedback Stimulation Device to Recover the Missing Sensation of the Upper Limb Amputees
Authors: Nemah Mohammed Najeh , Aldulaymi Omar Hammad , Low Cheng Yee , Che Zakaria Noor Ayuni , Mohamaddan Shahrol
Published: June 2020

Providing sensory feedback for prostheses users increases the manipulation ability, as well as introduces a feeling of the embodiment. A novel hybrid haptic feedback stimulation system of the amputees of upper limb mutilation was designed, developed, and evaluated in this study. The haptic wearable device was built by mean of single servomotor as a pressure feedback display and a pair of vibration motors as a vibration feedback display. Accordingly, the pressure display is responsible for conveying the missing sensing of the contact pressure and its force level. While the vibration display has utilized to provide an indication about the continued contact pressure. Able-body participants are engaged to evaluate the performance of the proposed feedback stimulation system. The results show that the participants are able to distinguish the touch, the start of touch, the end of touch, and the range of force with 100 % accuracy. While 96 % and 88 % of the able-body participants are capable to identify the grasp and the slipping objects, respectively. Furthermore, the ability of the proposed haptic wearable device to convey the tactile sensory information to the user’s brain without confusing or pre-training was improved.
Aerodynamics Analysis on the Effect of Canard Aspect Ratio on Blended Wing Body Aircraft using CFD Simulation
Authors: Ali Z. M. , Kuntjoro W. , Wisnoe W. , Ishak I. S. , Katon M. Z. , Ahmad N.
Published: June 2020

Blended Wing Body Aircraft (BWB) is an unconventional aircraft that combined the conventional and flying wing aircraft’s design. The unique design of the BWB offers a high fuel efficiency, low noise, and large payload volume for the size of aircraft. However, the BWB is unstable due to the absence of the its vertical stabilizer. A possible solution to improve this problem is using a horizontal control surface, the canard. For this purpose, the numerical simulation using NUMECA Computational Fluid Dynamic (CFD) software were conducted to obtain the aerodynamics forces subjected on this aircraft. The lift coefficient (CL), drag coefficient (CD) and moment coefficient (CM) are analysed at Mach number 0.1. The study is specifically to discuss the effect of canard setting angle ™ of BWB from ™ = -10° to 10° in that particular of aspect ratio (AR 2, 4, 6 and 8) towards aerodynamics parameters, CL, CD, and CM.
Improving Teaching and Learning Experience in Engineering Education Using Sentiment Analysis Techniques
Authors: Kaur Wandeep , Balakrishnan Vimala , Singh Baljit
Published: June 2020

Students are the golden commodity when it comes to ringing in revenue for academic institution. Therefore, it is vital to ensure the opinions and feedback of students is taken seriously to ensure continuous improvement in the teaching and learning experience. In an era of digital information and rich opinionated text being easily available, it is crucial to look into different forms of data analysis from which vital information can be extracted. Sentiment and emotion analysis are one such area of research that looks to extract implicit information from written text and analyse data that would be able to provide a deeper insight compared to conventional measures. This paper is an extension of a previously conducted study of analysing emotion as well as sentiment of students’ feedback taking Thermal Engineering (MEC551) from Universiti Teknologi Mara (UiTM). Supervised learning technique was adopted and data analysed revealed students were biased towards assignment and quizzes as these would help improve their carry forwards for the subject and the preference of chapters to the exam was more for conduction and convection compared to others which had more mathematical related calculation.
Computational fluid dynamics analysis on the effect of flow distribution on pedestrian in urban area
Authors: Abu Kasim Haszeme Bin , Bin Mohamad Mohd Faizal , Alias Siti Khadijah , Khalid Ahmad Hilmi , Bin Zainol Muhd Azhar , Ahmad Tajudin Nur Asyikin Binti
Published: June 2020

Buildings in urban area consist of various heights and building arrangements. Meanwhile, the pedestrians at the area must be considered for their wind comfort and wind safety. This is because, near high-rise buildings, high wind velocities are often introduced at pedestrian level that can be experienced as uncomfortable or even dangerous. Nowadays feasibility Computational Fluid Dynamics (CFD) for the assessment in wind engineering such as wind comfort and safety of pedestrian are very demanding. Hence, this study is conducted using CFD to analyses the effect of different building heights on the wind flow distribution towards pedestrian. The study was done on two different cases based on two different buildings (uniform height and non-uniform height) with squared and staggered arrangements. The turbulent wind over the pedestrian was acquired by solving the 3D steady state Reynold’s-Average Navier-Stokes (RANS) equations using RNG k-ε turbulence closure model. The results show that changes on the height of the buildings varies from the center of the urban canyon based on the vorticity of the flow distribution.
Effect of Welding Preheats on Metallurgical Analysis and Microstructural Development
Authors: Mazni Mazleenda , Bin Ismail Muhammad Hussain , Bin Pahroraji Hazriel Faizal , Malik Norjasween Abdul , Mohd Hamami Mohd Ghazali Bin , Sukarman F. , Sulong Nurulsaidatulsyida
Published: June 2020

This project is to study the effect of welding preheat on metallurgical analysis and microstructural development. Variables such as current, speed of welding and size of specimen were fixed. In the present work, a mild steel plate with thickness of 100 mm and width size of 20 mm was used. SMAW (Shielded Metal Arc Welding) technique was chosen as it is the easiest way to perform and widely used in oil & gas and marine industries. Three different preheat temperatures were performed during the study; ambient temperature (no preheat), between 60 °C to 70°C and greater than 200 °C. The study emphasizes on the minimum preheat temperature that produce good quality welding by taking into account some of metallurgical aspects; microstructure and macrostructure development, hardness distribution at important areas in weld (Heat Affected Zone, parent metal and weld area) through thickness. From this study, code American Welding Society (AWS) D1.1 was used as a reference and it stated that for plate that has 100 mm thickness the preheat temperature should be in the range of 60 °C and 70°C. The result of microstructure and macrostructure showed that the depth of penetration was not vary too much. Hardness measurement, macro and microstructure observation were performed in order to obtain a good correlation exist between these parameters studied.
A Case Study on Change Management Readiness for an Oil & Gas SME Company in Malaysia
Authors: Baharudin I. S. , Abdullah B. , Mohd Salleh N. A. , Shariffudin P.
Published: June 2020

Change management is vital in sustaining and remain competitive in a volatile environment. A well-planned change management effort has been craved by organizations in need as being more profitable, reputable and sustainable is the ultimate achievement. These changes to the pillars of the organization normally are more transformative than incremental in nature. All arrows pointing to the single biggest step an organization is to embark if they choose to ride the path of a successful change management execution – the change management readiness. This paper discusses the aspects of change management readiness which entails the need for readiness, the activities within readiness, the factors of leadership, communication and awareness that embodies the readiness as a whole. A case study of an actual organization participated in the study using leadership profiling assessment, organizational communication survey, change management awareness survey and maturity assessment. The results from this study is realistic and impactful to its readers. This paper validates the underlying theory of the three factors in a real industry environment and how successful change management readiness can be obtained with diligent planning and execution.
Tool-path Generation for Groove Machining Feature
Authors: Zubair Ahmad Faiz , Abu Mansor Mohd Salman
Published: June 2020

In this study, algorithm in generating machining sequences and tool-path for groove machining features are developed. The algorithm is based on ruled-based method and enhancing automatic feature recognition (AFR) via volume decompositions method. From the position of the vertex in z-axis and x-axis directions, machining sequences can be determined, and machining features can be sorted out. From the sub delta volume (SDV) generated from the recognized features of 3D part model, vertex positions of each SDV is determined thus positioning of the tool-path can be obtained. To validate the generated machining sequence and tool-path, one workpiece has been assigned to the algorithm. This workpiece is also tested with commercial software CAM function. The result shows that the developed algorithm is capable in generating the tool-path and can be visualized.
Crash Performance of Double Hat Column Subjected to Compression Loading
Authors: Salwani MS , Mohamad Hisyam K
Published: June 2020

There are many types of structure designed to act like an energy absorber. Energy absorber is the one that responsible to absorb energy during crashes. An energy absorber is a system that converts, totally or partially, kinetic energy into another form of energy. Energy converted is either reversible or irreversible. One of the examples of the most important structure to absorb energy is the crash box. Crash box can be found in many shapes, and double hat column is the common one. The objective of this study is to study the effect of heat treatment and notch on the performance of the double hat column structure. The results of different specimens were compared in terms of tensile strength and also energy absorbed. It was found that the tensile strength and energy absorbed was slightly higher for specimens that were quenched in lower temperature and longer time and for notching distance of 20mm.
CAE Analysis for Disposable Mouth Mirror Based on Autodesk Moldflow Plastic Insight
Authors: Saedon J B , Azlan Mujahidah Zaira , Adenan Mohd Shahriman , Azuddin M
Published: June 2020

This study is carried out to focus on computer aided engineering analysis on dental toolkit for disposable mouth mirror by using Autodesk Moldflow Insight (AMI) software. Disposable mouth mirror designs contain with a very small and precise features for it handles and fix angle between shank and working area (mirror). A 3D cad model of disposable mouth mirror has been construct and imported to the simulation software. The part has been analysed with thermoplastic material of Polypropylene (PP) as a part material for its light weight and durability. The simulation and analysis by moulding software package is used in order to determine the best range of operating parameter for injection moulding process in furtherance to get the low manufacturing defect. The process parameters that has been selected includes mould surface temperature, melt temperature, flow rate and cooling time during the injection moulding process. At the end, the best range of operating parameters has been proposed and simulates to study the product behaviour.
Analysis of distortion of coupled process forming to welding using fem-based virtual manufacturing with experimental verification
Authors: Ishak D P , Prajadhiana K P , Manurung Y H P , Sulaiman M S , Saberi M K A
Published: June 2020

In this paper, the numerical model of coupled process forming to welding by means of FEM is developed in order to analyse the displacement. Simufact. Forming and Simufact. Welding are utilized to execute a thermomechanical FEM analysis of forming to welding coupled process. Prior to welding process, a sheet metal bending process is performed in order to bend the 2mm plate into a U-shaped geometry. The material used for this process is S235 low carbon steel along with filler material ER70s. Goldak’s double ellipsoid model is chosen as the heat source model for GMAW simulation. A series of sheet metal bending and GMAW experiment is executed in order to verify the distortion result produced by FEM analysis. ABB IRB 2400/16 is the assigned robotic welding equipment used in GMAW process while sheet metal bending machine SUNFLUID 800/2007 is utilized for sheet metal bending process. For the calibration model, a forming force between FE simulation will be compared with the forming force of experimental bending process. The final results have shown that the distortion result of FEM analysis of coupled process forming to welding shows a good agreement with the experimental coupled process.
Anatomical modelling and simplified modelling in total hip replacement: difference in contact mechanics perspective
Authors: Manap M F A , Shuib S , Yamin A F M , Shokri A A
Published: June 2020

Total hip replacements (THR) is a surgical operation to replace defect bone at the hip joints. The rate of succession of THR post-operative still debatable as complication and failure rate of the prosthesis still exists. Edge-loading, dislocation, fracture and longevity are among the concerned issues with many studies were conducted via software analysis. This study aims to simulate the difference of anatomical and simplified modelling in finite element analysis (FEA) and investigate edge-loading effect at different inclination angle in both modelling conditions. A CT scan hemi-pelvic model was reshaped and converted into 3D model in SolidWorks and the next step, FEA was conducted in ANSYS Workbench V16 at different inclination angle. Anatomical and simplified model were run in ANSYS Workbench and the results were recorded. The anatomical modelling produced less contact pressure range 26% to 51% compared with simplified modelling at four inclination angle conditions. Von Mises stress and total deformation in anatomical also produced reduction of more than 65%. Both modelling conditions shows agreement that elevated inclination angle had induced higher contact pressure at superior region of acetabular cup. The inclusion of hemi-pelvic model gives lower value recorded in FEA as contact stress dispersed into the bone that already integrated with the implant given statistically significant (p<0.05). Noteworthy to include bone integration into implant during FEA study to produce unambiguous contact mechanics studies.
Emission characteristics of biodiesel ratios of 10%, 20%, and, 30% in a single-cylinder diesel engine
Authors: Jalaludin Helmisyah Ahmad , Abdullah Nik Rosli , Sharudin Hazim , Asiah A R , Jumali Muhammad Firdaus
Published: June 2020

This research is devoted to investigate the effects of biodiesel ratios of 10%, 20%, and 30% to the emission of single cylinder diesel engine. Fuel blends comprise of 10% (B10), 20% (B20), and 30% (B30) with adding 0.1 ml of additives to each litre of fuel blend volume are put to the test on a diesel engine, comparing each aspect to differentiate the best fuel blend. A reference experiment with 100% diesel (D100) had been done to have a clear view of the working diesel engine emissions. These blends were used for testing in a four stroke, vertical single-cylinder, air-cooled diesel engine at a constant speed of 1500 rpm as with varying engine load of 2, 4, and 6 Nm. Exhaust emissions of nitrogen oxide (NOx), carbon monoxide (CO), carbon dioxide (CO2), and unburned hydrocarbon (HC) are taken into account. The results show that the increase biodiesel blend in fuels does increase the NOx and CO2 emission with steady increase of load. This is because these emissions relate to the complete combustion, high post-combustion and high oxygen content increase the amount of emission. Besides, the results prove that the higher percentage of biodiesel in the blends provides lower emission of CO and HC. Lower CO and HC emission due to better combustion efficiency as it reaches better overall combustion, producing higher energy output and better emissions. Thus, the findings provide helpful information for researchers to understand the technology of biodiesel and a possible substitute for the current diesel for a better fuel source.
Enhanced application of virtual manufacturing: influences of material parameters on numerical Simulation of forming process
Authors: Sulaiman M S , Manurung Y H P , Graf M , Bauer A , Awiszus B , Omar A R , Kuntjoro W , Adenan M S
Published: June 2020

This paper describes the sensitive influence of material parameters on the final numerical simulation result of forming process as one of virtual manufacturing applications. Although existing commercial software system provide predefined material properties, these can nevertheless differ with the actual material which might result in inaccuracies. Hence, material data needs to be enhanced to gain better simulation results. This investigation begins with development of flow curve of steel DC04 (1.0338) based on compressive test with various effective plastic strains under consideration of rolling direction. Further, Forming Limit Diagram (FLD) is to be defined by using Nakajima test to determine the strains up to the fracture for deep drawing process. In this research, the enhanced application on sheet forming process is modelled and simulated as well as verified under laboratory condition using an oil-hydraulic press. It can be demonstrated that the numerical simulation results are very sensitive due to the essential differences in material properties. However, this procedure will lead to time and cost intensive measurements of the material behaviour, which is mandatory for an accurate forecast of real forming process.
The Effects of Sintering Schedule on Alloy Powder ASC 100.29 Compacts Formed at Elevated Temperature
Authors: Hasan Z , Ismail M A , Rahman M M
Published: June 2020

This paper presents the outcomes of an experimental investigations on the effect of sintering schedule i.e. holding time and temperature to the final properties of alloy powder ASC 100.29 formed through uniaxial die compaction process at elevated temperature. A lab-scale powder compaction rig with uniaxial compression and installation of heater was designed and fabricated in order to produce green compact from powder mass at elevated temperature. Alloy powder ASC 100.29 (99.7 wt%) and lubricant, zinc stearate (0.3 wt%) were mixed mechanically for 30 min at a rotation of 30 rpm. The powder mass was compacted at 150°C via simultaneous upward and downward uniaxial compression load of 425 MPa. Defect-free green compacts were generated from the compaction and were subsequently sintered at 1000°C using a custom argon gas fired furnace at three different sintering rates, i.e., 5, 10 and 15°C/min for three holding times, i.e., 30, 60 and 90 min, respectively. The final products were characterized through their physical, electrical and mechanical properties and their microstructures evaluated. The results revealed that the sample sintered for a longer period of time, i.e. 90 minutes at the slowest sintering rate, i.e. 5°C/min obtained the better final characteristics.
Experimental research and modelling of the response of magnetorheological elastomers to cyclic load
Authors: Petríková Iva , Marvalová Bohdana
Published: June 2020

Magnetorheological elastomers (MREs) belong to the new group of functional materials called “smart”. The MR effect is increased by choosing the material of the particles with high permeability. The dependence of dynamic moduli and damping of MREs on the external magnetic field and the applied frequency of cyclic shear deformation was studied. Samples of MRE were made of the silicon rubber matrix filled with micron-sized particles. The dynamic stiffness of MRE depends on magnetic flux density and rises with increasing frequency. The loss factor of MRE samples is controlled by the magnetic flux density and it depends also on the testing frequency. The behaviour of viscoelastic materials under uniaxial loading may be represented using rheological models composed of elastic and viscous elements. The dynamic variables storage and loss moduli and loss tangent were determined on the basis of the fitted parameters of the fractional model.
Antioxidant Activities Bioactive Compound of Ethyl Acetate Extracts from rose myrtle Leaves (Rhodomyrtus tomentosa (Ait.) Hassk.)
Authors: Salni  , Marisa Hanifa , Repi Lili Arista
Published: June 2020

One of the plants traditionally used as medicine is rose myrtle (Rhodomyrtus tomentosa (Ait.) Hassk.). Rose myrtle has the potential as an antioxidant because it has secondary metabolites including flavonoids, phenols, terpenoids, tannins, saponins, and steroids. The purpose of this study was to determine the fraction that has antioxidant activity and obtain antioxidant compounds from ethyl acetate extract of rose myrtle leaves. The research methods included extraction by Soxhletasi, fractionation by vacuum liquid chromatography, purification of compounds with gravity columns, and antioxidant activity test using the DPPH method. The results obtained 32% yield of ethyl acetate extract which was then followed by fractionation. The fractionation results obtained 13 fractions. The fractions that have antioxidant activity namely fractions 5-6, 7, and 8. The fraction was continued to purification and obtained by compound E.1, compound E.2 from the essential oil, and compound E3 allegedly rhodomyrtone. The bioactive compound determined by IC50 value obtained that E1, E2 and E3 that have IC50 value of 218, 207 and 90 μg/mL, respectively. The bioactive compounds of ethyl acetate extract have strong antioxidant activity in E3 and very weak in E1 and E2 compounds.
Methylene Blue Adsorption Isotherm on Spirulina sp. Microalgae Biomass Coated by Silica-Magnetite
Authors: Kausar R A , Buhani  , Suharso
Published: June 2020

In this study, it has been performed modification of Spirulina sp. algae biomass with silica (HAS) coated with magnetite particles (HASM) and its adsorption test on a solution of methylene blue dye (MB) in solution. The identification of functional groups from HASM adsorbent was studied using infra-red (IR) spectrophotometer, the degree of crystallinity of the material was determined by X-ray diffraction (XRD), while the morphology and HASM constituent elements were analyzed by Scanning Electron Microscopy-Energy-Dispersive-X-Ray (SEM-EDX). The HASM adsorption isotherm of MB solution was studied by applying adsorption experiments using the batch method. The concentrations of MB dye in the adsorption process were analyzed by a UV-Vis spectrometer. Adsorption of 100 mg L−1 MB dye solution by HASM adsorbent at pH of 6 with a contact time of 60 minutes resulted in an adsorbed MB amount of 90.90 mg g−1. The adsorption isotherm model of the MB dye solution in the HASM adsorbent tends to follow the model of Freundlich adsorption isotherm. The adsorbent HASM is the effective adsorbent to absorb MB dye in solution.
Radioluminescence by synchrotron radiation with lower energy than the Cherenkov light threshold in water
Authors: Hirano Yoshiyuki , Komori Masataka , Onoda Daichi , Nagae Takayuki , Yamamoto Seiichi
Published: June 2020

Radioluminescence by protons and carbon ions of energy lower than the Cherenkov threshold (∼260 keV) in water has been observed. However, the origin of the luminescence has not been investigated well. In the present work, we imaged radioluminescence in water using synchrotron radiation that was of sufficiently lower energy (11 keV) than the Cherenkov threshold and we measured its spectrum using a high-sensitivity cooled CCD camera and optical longpass filters having 5 different thresholds. In addition, to determine effects of impurities in water, the water target was changed from ultrapure water to tap water. Monte Carlo simulation (Geant4) was also performed to compare its results with the experimentally obtained radioluminescence distribution. In the simulation, photons were generated in proportion to the energy deposition in water. As a result, the beam trajectory was clearly imaged by the radioluminescence in water. The spectrum was proportional to λ
−3.4±0.4 under an assumption of no peaks. In the spectrum and distribution, no differences were observed between ultrapure water and tap water. TOC (total organic carbon) contents of ultrapure water and tap water as an impurity were measured and these were 0.26 mg l−1 and 2.3 mg l−1, respectively. The radioluminescence seemed to be attributable to water molecules not impurities. The radioluminescence distribution of the simulation was consistent with the experimental distribution and this suggested that radioluminescence was proportional to dose, which is expected to allow use for dose measurement.
A facile synthesis of CDs from quinoa for nanosensors and bio-imagining
Authors: Xu Dandan , Li Yong , Li Naixin , Lei Fang , Liu Jinliang , Shi Ying , Yin Luqiao , Zhang Lei
Published: June 2020

Carbon dots (CDs) with strong fluorescence were synthesized by a facial and green hydrothermal method using biomass quinoa as the carbon source. The as-prepared carbon dots (CDs) aqueous solution shows bright blue photoluminescence under the irradiation of UV lamp with a quantum yield of 14% and considerable luminescence stability and excellent strong photobleaching resistance. The as-prepared CDs was nontoxic for in vitro and in vivo applications. In addition, not only the as-prepared CDs were used for HeLa cells imaging, but also detect Fe3+ ions in cells, and the ideal imaging pictures were obtained under excitation of 405 nm. The as-prepared carbon dots possessed excellent responsive properties towards Fe3+. The quenching phenomenon can be used to detect the Fe3+ ions within a linear range of 0–300 μmol l−1 with a limit of detection of 50 nmol l−1.