bluuebunny/crossref_metadata_2025_split huggingface dataset:
Samarium (III) oxide thin film as a saturable absorber for the passively Q-switched Tm-doped fiber laser
Authors: Rusdi K N , Hisyam M B , Rusdi M F M , Zulkipli N F , Latiff A A , Harun S W , Saidin N 
Published: December 2019

Abstract
We have demonstrated a passive Q-switched Thulium-doped fiber laser (TDFL using samarium oxide (Sm2O3) nanomaterial as saturable absorber (SA). The Sm2O3 based SA was fabricated by simply mixing the Sm2O3 powder solution with polyvinyl alcohol (PVA) solution. The homogeneously mixed solution was spread and dry to form a thin film. A piece of 1 mm x 1 mm of the SA thin film is sandwiched between two fiber ferrules and incorporated into a TDFL ring cavity for pulses generation. By controlling the loss and gain in the cavity, stable Q-switching operation was generated. The repetition rate was tunable from 17.62 kHz to 29.20 kHz by varying the pump power from 619 mW to 784 mW. The smallest pulse width of 3.54 µs and the highest pulse energy of 0.20 uJ were obtained at the highest pump power.
Microfibre deposited NiS2 for all-fibre optical thresholding
Authors: Li Shi , Yin Yu , Wang Pengfei 
Published: December 2019

Abstract
We demonstrate a microfibre deposited NiS2 for optical thresholding. By employing the fabricated NiS2 device, an all-optical thresholding function based on the saturable absorption effect has been successfully realized. The signal-to-noise ratio of the input pulse signal can be improved from 2.7 dB to 14.5 dB. The results achieved indicate that this NiS2-based microfibre device could be operated as an excellent nonlinear photonics device for all-optical signal processing.
Unprecedented recent late-summer warm extremes recorded in tree-ring density on the Tibetan Plateau
Authors: Duan Jianping , Wu Peili , Ma Zhuguo , Duan Yawen 
Published: December 2019

AbstractTree-ring records have shown a significant upward trend of late summer temperatures over the Tibetan Plateau (TP) in recent decades. More detailed instrumental observations over the TP have also shown an increase in warm extremes, especially in the high-altitude area. It is not clear whether the recent increase in occurrence of warm extremes on the TP reflects an amplification of recent temperature fluctuations or it relates to the long-term climate trend. This study aims to address the above question by analyzing long-term late summer (August–September) temperature extremes over the TP using temperature reconstructions derived from tree-ring maximum latewood density. Our results show that the recent frequency of late summer warm extremes was unprecedented over the past four centuries, while the occurrence of cold extremes in the instrumental interval was minimal. However, after the removal of long-term trend, the frequencies of both warm and cold extremes in the instrumental period are actually smaller than the pre-instrumental period, indicating a decreased variability of late summer temperatures. Thus, we conclude that the recent observed increase in warm extremes is related to the long-term warming trend, rather than an amplification of temperature variability. This finding implies that the persistent warming on the TP in the future might trigger much more frequent warm extremes with potential ecological and environmental effects.
Elucidating emissions control strategies for ozone to protect human health and public welfare within the continental United States
Authors: Lyu Congmeng , Capps Shannon L , Hakami Amir , Zhao Shunliu , Resler Jaroslav , Carmichael Gregory R , Sandu Adrian , Russell Armistead G , Chai Tianfeng , Henze Daven K 
Published: December 2019

Abstract
Ground-level ozone, which forms photochemically in the atmosphere from precursor emissions of oxides of nitrogen (NO
x
) and volatile organic compounds, is a criteria pollutant that harms human health and public welfare. For a representative summer episode, premature mortality and potential productivity losses (PPLs) of selected crops and trees attributable to ozone exposure have been quantified using ozone fields from the Community Multiscale Air Quality (CMAQ) model. We applied exposure-response models for the increased risk of premature mortality due to long-term exposure to ozone over a theoretical minimum risk exposure level (TMREL) and for the reduced accumulation of vegetative biomass for four crop species and eleven tree species using the W126 metric designed to capture impacts on plants. To elucidate which emissions contributed to these disbenefits, we applied adjoint-based sensitivity analysis, which efficiently estimates sensitivities of concentration-based metrics with respect to numerous emissions parameters simultaneously. The adjoint of CMAQ was applied to the continental US to calculate the influence of spatially-resolved ozone precursor emissions on the annual average, domain-wide daily maximum 8 h average over the TMREL (elevated MDA8), premature mortality attributable to exposure to ozone above the TMREL, and PPLs. These quantities provide the impact in terms of the percent reduction in precursor emissions. Additionally, locations where similar percent reductions in ozone precursor emissions would impact one or more endpoints greater than average have been identified. NO
x
emissions were found to contribute most to the three metrics. The distinct spatial patterns of emissions influences on public welfare disbenefits as compared to the elevated MDA8 and premature mortality suggest that the current regulatory averaging time motivates different emissions control strategies than those that could most directly protect public welfare.
Application of ductility exhaustion based damage model to predict creep rupture time of grade 92 steel
Authors: Alang N A , Razak N Ab 
Published: December 2019

Abstract
To accurately predict the creep rupture time of notched bar becomes a challenge to academia and structural engineer due to complex stress-strain distribution around the notch throat. This paper presents a Finite Element (FE) simulation employing ductility exhaustion based damage model to predict creep rupture time of multiaxial notched bar Grade 92 steel. Three different notch acuity, η = 2.5, 5.0 and 12.0 were simulated and the FE predicted rupture time was compared to the available experimental rupture data. The reduction of creep ductility due to geometrical constraint is considered during the simulation by employing the void growth model. Further reduction in ductility in long term period arises from internal microstructural changes or damage is also accounted. Furthermore, empirical-type exponential prediction model coupled with skeletal stresses is applied to provide upper/lower bounds for short and long term rupture data. It is found that the FE prediction agreed well with the experimental data. At short-term, notched bar ruptured is controlled by the von-Mises stress while at long-term the rupture is controlled by the maximum principal stress.
Thermal Comfort Study of a Classroom in Northern Malaysia: A CFD Approach
Authors: Suhaila H , Suhaimi I , Mohamed M A S , Mustaffa M T , Kartini A , Atikah A 
Published: December 2019

Abstract
A conducive environment is essential in creating an ideal condition for the impartment of knowledge. One of the essential parts of such a conducive environment is to have a thermally comfortable condition. A study was conducted to assess the thermal comfort in one of the classrooms of a university located in the northern most part of Malaysia. The particular classroom was randomly chosen from a total of 4 classrooms of the same size and condition. Measurements of the dimensions of the room together with temperature and velocity were taken to make the computational model and as boundary conditions for the Computational Fluid Dynamics (CFD) simulation. The simulation was conducted to visualize and predict the temperature distribution and flow pattern inside the classroom. The results of the simulation showed that there exists a non-uniform circulation of cold air from the air-conditioning outlet to the rest of the classroom. The distribution of the cold air seems to be limited to only the location under the air-conditioning outlet making it thermally uncomfortable there. Hence, it is recommended to either reduce the airflow velocity coming out of the air-conditioning outlet or change the size or location of the air-conditioning outlets.
Investigation on the effect of drilling parameters on tensile loading of fibre-metal laminates
Authors: Azwan S , Sahira N I , Abdullah M R , Yahya M Yazid 
Published: December 2019

Abstract
This study conducted to investigate the effect of different drilling parameters on the strength of vacuum infusion fibre reinforced epoxy resin-based fibre metal laminates (FML). The effect of several parameters such as the speed of drilling (1050, 2020, and 2750 rpm) and feed rate of (0.05, 0.1, and 0.15 mm/rev), and the thickness of FML on the strength of the composite materials were studied experimentally. The FML has been analysed under static loading. Drilling at lower spindle speed and lower feed rate results in better strength than higher spindle speed and feed rate. Then, the thicker FML gives more strength compare to the one with less thickness.
Effect of synthetic fibres on tensile properties of Napier fibres reinforced epoxy composites
Authors: Ridzuan M J M , Majid M S Abdul , Khasri A , Cheng E M , Sulaiman M H , Basaruddin K S 
Published: December 2019

Abstract
This paper present the effect of synthetic fibres on the tensile properties of Napier fibres reinforced epoxy composites. The composites were fabricated using the vacuum infusion method, which the Napier grass fibre placed between the synthetic fibres, then mixed the epoxy resin with a ratio of fibres and epoxy was 70:30. There were four different types of composite samples were fabricated based on various volume fractions. The samples were manufactured using vacuum infusion process. The composites are tested using a universal testing machine according with ASTM standard D638. The tensile strength of the hybrid synthetic/Napier fibre reinforced epoxy composites increased as the content of the synthetic fibre content increased. The tensile properties of the hybrid carbon/Napier reinforced epoxy composites were observed higher than the hybrid glass/Napier reinforced epoxy composites.
Implementation of multi-component dusty-gas model for species transport in quasi-three-dimensional numerical analysis of solid oxide fuel cell. Part I: hydrogen fuel
Authors: Tan W C , Iwai H , Kishimoto M , Yoshida H 
Published: December 2019

Abstract
Quasi-three-dimensional numerical model of solid oxide fuel cell, which assumes constant physicochemical properties within the cell components in the thickness direction, typically employs a simple gas diffusion model for species transport in the porous electrodes, such as the Fick’s model. In this study, a three-dimensional grid system is introduced in the anode layer and coupled with the quasi-three-dimensional solid oxide fuel cell model. The multi-component dusty-gas model is implemented to solve the conservation of species on this three-dimensional grid system. The results with the developed model are compared with experimental data obtained under hydrogen fuel. The obtained results show that the dusty-gas model can accurately predict the transport of gas species in the porous anode.
A short review on the use of coconut shell powder as filler in cement concrete
Authors: Nadzri S N I H A , Sultan M T H , Shah A U M , Safri S N A 
Published: December 2019

Abstract
Environmentally-friendly composites had been the interest of researchers nowadays. Therefore the use of natural sources to gradually replace the conventional materials had been rapidly developed. Besides the use of natural fibres as reinforcement in polymer matrix composites, the use of fillers from natural sources, such as rice husk and corn cobs, was implemented in ceramic matrix composites. Solid waste like coconut shell is one of the potential material to be used as filler in this composites. Coconut shell in powder forms is usually used together with cement to produce high strength, more durability and lightweight concrete for structural component in construction area. Based on this review paper, coconut shell concrete showed comparable mechanical properties to the conventional concrete, in terms of its compressive strength. These properties suggested coconut shell powder as potential material to replace course aggregate in concrete.
Static analysis on Malaysian Yankee’s pineapple leaf fiber/epoxy composite
Authors: Najeeb M I , Sultan M T H , Shah A U M , Safri S N A 
Published: December 2019

Abstract
The static analysis on pineapple leaf fibre (PALF) reinforced epoxy composites was carried out in this study. The effect of fiber alignment in X and Y axis were studied while maintaining total fiber loading of 10% by weight. The bending and compression strength were analyzed by performing flexural and compression test. The composite properties was strongly influence by the fiber orientation where Y axis shows improvement about 97% in bending and 5.3% in compressive strength compared to neat epoxy. However, as for X orientation bending test shows lower bending strength compared to neat epoxy but improve 4% in compressive strength. It can be concludedthat the fiber alignment in Y-direction is more suitable to be utilized for automotive interior or household applications that demand high strength properties.
Receding height of water droplet in the film boiling regime
Authors: Illias S , Hussain S , Rosman N A , Abdullah N S , Shaiful A I M , Omar M N B , Ismail K A , Ani H 
Published: December 2019

Abstract
The purpose of this research was to study and investigate the receding height of water droplet after it impinged on hot aluminum surface. On top of that, we also investigated the relationship between this receding phenomenon and residence time of water droplet. Degassed and distilled water was used as a droplet. The droplet diameter was maintained at 4.0 mm and the impact height was set to be around 65.0 mm corresponding to impact velocity of 1.129 m/s. The liquid temperature was kept around 16 °C corresponding to liquid subcooling of ΔT

sub
= 84 K. The material selected in this experiment was aluminum surface. The surface had been polished until it became a mirror polished surface. The dimensions of the material surface were 30.0 mm in diameter and 8.0 mm in height. The phenomena were recorded at 10,000 frames per second using a high speed video camera. As a result, it was observed that the receding height during film boiling regime was almost similar to each other even the surface temperature was different. Furthermore, the residence time during the experiment was also close to the theoretical calculation.
Analysis of insertion and removal torque loading for miniscrew and miniplate skeletal anchorage
Authors: Khor Z H , Daud R , Kamarrudin N S , Ibrahim I , Mat F , Basaruddin K S 
Published: December 2019

AbstractMini-Implant such as miniscrew and miniplate is used as a stabilizer in stable the crack occurs at the mandibular bone and maxillary bone for recovery. Reducing the screw loosening may reduce the trauma of insertion and removal that able to increase the rates of osseointegration. This paper presents the investigation of stress transfer between the interaction mini-implant and bone during applied in insertion and removal torque regards to stress distribution between mini-implant and bones. The finite element simulation involves three different materials mini-implant such as Titanium Alloy, (TiA), Stainless Steel, (SS) and Magnesium Alloy, (MgA). The result identified that the best material of mini-implant used to insert at mandibular bone is Titanium, (TiA) with the moment of 90 Nmm to perform high 0.70 STP value and average SEDTP of 2.60 compared to other materials. Whereas, for the material of mini-implant used to inserted at maxillary bone is Magnesium Alloy, (MgA) with the moment of 100 Nmm to perform high 1.11 STP value and average SEDTP of 1.20.
Biomechanical analysis of patient-specific femur model of osteogenesis imperfecta with cortical and cancellous bone
Authors: Tan L C , Som M H Mat , Basaruddin K S , Yazid H , Daud R , Awang M S 
Published: December 2019

Abstract
Osteogenesis imperfecta (OI) is a fragile bone disease characterized by easy fractures. The femur consists of cortical and cancellous bone, each with different mechanical properties. Bone fractures often occur throughout patients’ lifetime. However, doctors still have no quantitative method to predict fractures. This project’s purpose is to investigate the mechanical behaviour of patient-specific OI femur from the finite element analysis. The fracture risk in daily activities (ADL) were examined. All the stress values were judged by the fracture criteria, assumed as 115 MPa. The exercises that exerted force more than 6 times of body weight could cause fractures. Cancellous bone was not affected in any case of ADL. The effects of force and stress on cancellous bone and its impact on fracture risk are negligible.
Tribological properties of DLC coating under lubricated and dry friction condition
Authors: Sulaiman M H , Farahana R N , Mustaffa M N , Bienk K 
Published: December 2019

Abstract
Increasing demands on reducing abundant use of environmentally hazardous lubricants like chlorinated paraffin oil in production motivates extensive research on dry friction condition. However, the dry friction condition is not favourable, and it causes high friction and severe wear problems. This paper presents the tribological behaviour of a new hard coating, namely double-layer DLC/TiAlN, deposited onto the tool steel surface via a Physical Vapour Deposition (PVD) process. A pin-on-disk tribometer was used to study the long-term performance of DLC/TiAlN coated tool steel under lubricated and dry friction conditions. Surface damage after the experiment was observed by using a light optical microscope (LOM) and also, analysed by measuring wear scar profiles with a tactile roughness profilometer. The results were compared with uncoated tool steel. Based on the experimental result, applying the DLC/TiAlN coating to the tool steel surface has led to a significant reduction of friction and almost no wear scar was observed. The study proved that the DLC/TiAlN coating contributes to the better wear life of the tool steel, thereby improving the tool lifetime.
Laboratory development of low speed wind tunnel for educational purposes
Authors: Siregar R A , Umurani K 
Published: December 2019

Abstract
In this paper presents the design and development of wind tunnel for education purposes. The wind tunnel is designed as an open-type, low speed, able to provide wind speeds up to 20 m/s and maximum turbulent intensity is 5%. A 70 cm tube axial fan is driven by a 3 hp motor using a variable frequency drive to allow continuously variable wind speeds. The size of testing chamber is about 40 cm by 40 cm, large enough to conduct experiments such as drag coefficient, airfoil and wing. Preliminary test of air flow in testing chamber shows that wind tunnel is particularly suitable not only for education but also for aerodynamic researches.
CFD analysis of hydrodynamic lubrication effects of micro textured surface
Authors: Sulaiman M H , Zaid M F S , Farahana R N , Ridzuan M J M 
Published: December 2019

Abstract
A great number of lubricated mechanical components everywhere in life. Improvement in efficiency would lead to greater cost savings in many engineering applications. In the present paper, an approach to increase the efficiency in hydrodynamic lubrication for applications in metal forming processes by surface texturing was studied using Computational Fluid Dynamics (CFD) simulation. A two-dimensional fluid domain containing a flat upper wall with a tangential velocity and a static lower wall containing an oblong groove of the same sizes was studied. This includes the effect of varying distances between grooves on lubrication. With an isothermal lubrication flow condition and parallel walls, the pressure in the lubricant domain produces largest load carrying capacity and wall shear force, indicating large contact area contributes to an increase of frictional force. The present study revealed that the positive influence on hydrodynamic lubrication performance can be achieved by introducing a textured surface. Larger distance between the grooves has effectively produced a pressure build-up in the lubricant domain introducing a larger load carrying capacity. It is seen that a load carrying capacity exists for a small distance between the grooves.
Effect of surface treatment on drag coefficient of free-falling solid sphere in water
Authors: Mohamad M Sofwan , Dover C M Mackenzie , Sefiane K 
Published: December 2019

Abstract
The study aims to examine the influence of different surface treatments on the drag coefficient of free-falling spheres in water. The spheres used in the experiment are classified into four categories and labelled as: ref – no surface treatment, FDTS – coated with hydrophobic perfluorodecyltrichlorosilane (FDTS) coating, E8 – 8 minutes etched in ferric chloride (FeCl3) and E32 – 32 minutes etched in FeCl3. No significant difference is observed in drag coefficient of the etched spheres compare with the reference sphere. However, the FDTS sphere’s drag coefficient was increased by 13%.
Dynamic oblique crushing of single and bi-tubular aluminium conical tubes with imperfection
Authors: Mat Fauziah , Nazreen Hani Mohammad Syarul , Md Rejab Md Noor Arib 
Published: December 2019

Abstract
This paper aims to study the crashworthiness response of single and bi-tubular aluminium conical tubes subjected to oblique loading. The influence of imperfection on crashworthiness criteria is studied by introducing circular cutouts to the single and bi-tubular conical tubes. The explicit finite element (FE) code LS DYNA is employed to develop the FE model of the tubes. Satisfactory agreement between the developed FE model and previous experimental work has been obtained. The validated model is then employed to investigate the influence of imperfection on the tubes based on internal energy at maximum deformation. The finding shows that with the introduction of cutouts, the energy absorption capability and Specific Energy Absorption (SEA) of bi-tubular tubes are improved as high as 3.43 % and 3.44 %, respectively compared to the single tubes. Compared to the tubes without cutouts, there is a reduction of the internal energy and the SEA of the tubes with cutouts. For bi-tubular tubes, the reduction of the energy absorbed is only 6.41 % thus implies that bi-tubular tubes are better than single tubes when subjected to oblique loading. The similar pattern is also found in the SEA. Furthermore, the increase in loading angle, α reduces the internal energy and the SEA.
Evaluation of square deep drawn AA6061-T6 blank based on thinning pattern
Authors: Yusop N M , Abdullah A B 
Published: December 2019

AbstractDeep drawing can be generally described as a process of converting a metal sheet into a desired shape and geometry. Material flow and formability of the blank depends on the die and the punch geometries and it is important to predict the material behavior during square deep drawing to reduce possibility of defect and part rejection. In this research, a 3D Finite Element (FE) model is developed to simulate the square deep drawing process of an AA6061-T6 material using ANSYS Explicit Dynamics. The developed model can be used to predict the thinning pattern of the blank especially at the corner area. This research focus on the effect of design parameters namely punch corner radius (R1), punch nose radius (R2), die corner radius (R3) and die shoulder radius (R4) towards thinning pattern.