bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation and characterisation of the microstructure of ultra-fast heated dual-phase steel
Authors: Banis A. , Bouzouni M. , Petrov R. H. , Papaefthymiou S.
Published: June 2020

The current study focuses on the composition of the constituents that are obtained from ultra-fast heating and the composition of the parent austenite that was achieved at the peak temperature. In order to analyse the content and distribution of important elements such as carbon, manganese, chromium and molybdenum in the microstructure, simulation software was used. It is also found that the content of these elements shows a gradient in the microstructure in relation to the distance from the undissolved cementite. This leads to carbon-rich areas in the vicinity of cementite and carbon-depleted areas as the distance from the cementite grows. The former creates ideal conditions for the retainment of austenite due to the higher carbon content while the latter creates conditions that enable the formation of bainite in the microstructure.
The inverse problem of reconstructing reaction–diffusion systems
Authors: Kaltenbacher Barbara , Rundell William
Published: June 2020

This paper considers the inverse problem of recovering state-dependent source terms in a reaction–diffusion system from overposed data consisting of the values of the state variables either at a fixed finite time (census-type data) or a time trace of their values at a fixed point on the boundary of the spatial domain. We show both uniqueness results and the convergence of an iteration scheme designed to recover these sources. This leads to a reconstructive method and we shall demonstrate its effectiveness by several illustrative examples.
Ion acoustic solitary and shock waves in strongly coupled degenerate plasma with relativistic effects
Authors: Patidar Archana , Sharma Prerana
Published: June 2020

The ion acoustic solitary and shock waves are studied in strongly coupled nonrelativistic and relativistic plasma. The wave profile has been discussed for the kinetic and hydrodynamic regimes. The ions are considered to be strongly coupled, and electrons as degenerated and relativistic to deal with nonlinear waves using continuity and Poisson’s equations together with generalized hydrodynamical (GH) and quantum hydrodynamical (QH) models. The reductive perturbation method is used to formulate Korteweg–de Vries (KdV) and Korteweg–de Vries Burgers (KdVB) equations in both nondegenerate and degenerated cases. The effects of relativistic, degeneracy parameter and longitudinal viscosity coefficient on the profile of nonlinear waves are discussed. The amplitude and width of a shock in both nonrelativistic and ultrarelativistic cases increase with an increase in the viscosity coefficient, while with an increase in the electron diffraction parameter, the amplitude and width of the shock wave increase, and for a solitary wave decreases in both the nonrelativistic and ultra-relativistic cases. It is also shown that solitary ion acoustic wave propagates with more energy in nonrelativistic plasma than ultrarelativistic. The results of the work will be useful, for example, for astrophysics to understand the process of wave propagation in dense astrophysical bodies.
Energy transfers in magnetohydrodynamic shear turbulence
Authors: Nauman Farrukh , Guseva Anna
Published: June 2020

Astrophysical flows span a broad range of scales and thus require sub-grid modeling. We compute the energy fluxes in the Fourier and physical space for the turbulent magnetized shearing box simulations with a weak net vertical magnetic flux. The energy fluxes are dominated by the injection term from the mid-to-large scale range due to the Reynolds and Maxwell stresses in both cases while the small scales are dominated by dissipation. Since the nature of turbulent cascades requires a clear separation of scales, our work is unable to address these questions conclusively. But because our work is the first of its nature in trying to connect the Fourier and physical space energy flux behavior, we are able to make connections between the two profiles.
On the Lyapunov spectrum of an ensemble of vortices
Authors: van Veen L , Vela Martín A , Kawahara G
Published: June 2020

In space- and time-dependent dynamical systems, Lyapunov vectors correspond to spatio-temporal patterns of instability. These patterns can be used to parse and predict the interaction and break-down of coherent structures. The computation of Lyapunov vectors, however, is computationally demanding and has hitherto been restricted to systems with a comparatively low attractor dimension. We aim to study the dynamics of vortices in developed turbulence with an attractor dimension of order O(100). To this end, we compute the linear stability spectrum of an unstable periodic orbit embedded in the turbulent attractor and consider it a proxy for the Lyapunov spectrum. Along the periodic orbit at least 25 Lyapunov vectors can give the largest growth rate locally in time and space. We highlight one instance of a mutually induced instability of a vortex pair localized in the high-strain interstitial region.
On the structure of streamwise wall-shear stress fluctuations in turbulent channel flows
Authors: Cheng Cheng , Li Weipeng , Lozano-Durán Adrián , Fan Yitong , Liu Hong
Published: June 2020

In this study, we use a two-dimensional clustering methodology to identify the high-and low-speed structures of the streamwise wall-shear fluctuations in turbulent channel flows at different Reynolds numbers. The statistical properties of the high- and low-speed structures, such as geometrical characteristics, fluctuating intensities and conditional velocity fluctuations, are shown to be remarkably asymmetrical. The low-speed structures are closely related with the celebrated attached eddies. Our work may aid to the future development of the attached-eddy model.
Sub-Grid modelling based on vorticity-stretching
Authors: Bing Deng Xiao , Dong Siwei
Published: June 2020

A non-isotropic vorticity dyadic tensor (VDT) sub-grid scale model is developed. Based on the direct numerical simulation database of channel turbulence, the sub-grid scale energy dissipation of the model in wall-bounded turbulence is studied, and a wall damping function for VDT model is developed. The sub-grid scale energy dissipation produced by the wall-corrected VDT model is more accurate than that of the Smagorinsky model with Van Driest damping and the dynamic Smagorinsky model.
Dependence of tropical cyclone damage on maximum wind speed and socioeconomic factors
Authors: Ye Mengqi , Wu Jidong , Liu Wenhui , He Xin , Wang Cailin
Published: June 2020

Tropical cyclones (TCs) have devastating impacts and are responsible for significant damage. Consequently, for TC-induced direct economic loss (DEL) attribution all factors associated with risk (i.e. hazard, exposure and vulnerability) must be examined. This research quantifies the relationship between TC-induced DELs and maximum wind speed, asset value and Gross Domestic Product (GDP) per capita using a regression model with TC records from 2000 to 2015 for China’s mainland area. The coefficient of the maximum wind speed term indicates that a doubling of the maximum wind speed increases DELs by 225% [97%, 435%] when the other two variables are held constant. The coefficient of the asset value term indicates that a doubling of asset value exposed to TCs increases DELs by 79% [58%, 103%]; thus, if hazard and vulnerability are assumed to be constant in the future, then a dramatic escalation in TC-induced DELs will occur given the increase in asset value, suggesting that TC-prone areas with rapid urbanization and wealth accumulation will inevitably be subject to higher risk. Reducing the asset value exposure via land-use planning, for example, is important for decreasing TC risk. The coefficient of GDP per capita term indicates that a doubling in GDP per capita could decrease DELs by 54% [39%, 66%]. Because accumulated assets constantly increase people’s demand for improved security, stakeholders must invest in risk identification, early warning systems, emergency management and other effective prevention measures with increasing income to reduce vulnerability. This research aims to quantitatively connect TC risk (expected DELs, specifically) to physical and socioeconomic drivers and emphasizes how human dimensions could contribute to TC risk. Moreover, the model can be used to estimate TC risk under climate change and future socioeconomic development in the context of China.
Evidence-based mapping of the wildland-urban interface to better identify human communities threatened by wildfires
Authors: Miranda Alejandro , Carrasco Jaime , González Mauro , Pais Cristobal , Lara Antonio , Altamirano Adison , Weintraub Andrés , Syphard Alexandra D
Published: June 2020

The wildland-urban interface (WUI) is the spatial manifestation of human communities coupled with vegetated ecosystems. Spatial delineation of the WUI is important for wildfire policy and management, but is typically defined according to spatial relationships between housing development and wildland vegetation without explicit consideration of fire risk. A fire risk-based definition of WUI can enable a better distribution of management investment so as to maximize social return. We present a novel methodological approach to delineate the WUI based on a fire risk assessment. The approach establishes a geographical framework to model fire risk via machine learning and generate multi-scale, variable-specific spatial thresholds for translating fire probabilities into mapped output. To determine whether fire-based WUI mapping better captures the spatial congruence of houses and wildfires than conventional methods, we compared national and subnational fire-based WUI maps for Chile to WUI maps generated only with housing and vegetation thresholds. The two mapping approaches exhibited broadly similar spatial patterns, the WUI definitions covering almost the same area and containing similar proportions of the housing units in the area under study (17.1% vs. 17.9%), but the fire-based WUI accounted for 13.8% more spatial congruence of fires and people (47.1% vs. 33.2% of ignitions). Substantial regional variability was found in fire risk drivers and the corresponding spatial mapping thresholds, suggesting there are benefits to developing different WUI maps for different scales of application. We conclude that a dynamic, multi-scale, fire-based WUI mapping approach should provide more targeted and effective support for decision making than conventional approaches.
Durian pectin and rice husk ash (RHA) as partial replacement of cement in concrete
Authors: Chia Soi Lee , Zamri Zamsalwani , Muniandy Amruthavarsini , Joseph Evania , Sathasivam Jezzindren
Published: June 2020

Cement is one of the important materials in concrete mixture and use for building construction. High demand for cement usage due to the rapid development of construction in the country needs to be addressed. The objective of this study is to identify the workability and compressive strength of concrete at different level of replacement of cement. Cement was replaced with durian pectin and RHA by weight at 10%, 15% and 20%. Compressive strength and water absorption test were carried out on hardened 150mm x 150mm x 150mm concrete cubes after 7, 14 and 28 days of curing. The results revealed that the compressive strengths reduced as the percentage durian pectin and RHA increased in same ratio 5:5, 7.5:7.5 and 10:10. The sample consist of 5% of durian pectin and 5% of RHA is the optimum ratio replacement of cement in concrete with highest compressive strength 27.5 N/mm2, medium workability and water absorption 6%.
Influence of superplasticizer on performance of cement – bottom ash concrete
Authors: Che Amat R , Ismail K N , Mohamad Ibrahim N , Azmi N J
Published: June 2020

The issue related to disposing waste material from industries has become one of the major environmental, economic and social problems. However, natural resources consumed worldwide, while at the same time increased amount and type of the waste material has resulted in waste disposal crisis with a growing consumer population. Therefore, the solution to this crisis is recycling waste into useful materials. In this project, Municipal Solid Waste Incineration (MSWI) by product which is bottom ash is used as partial replacement in cement. However, its properties as water absorbent become the issue for concrete strength. This research paper is to investigate the influence of superplasticizer on performance of cement-bottom ash concrete and designed for strength of 20 MPa at 28 days will be evaluated for its early stage properties. Superplasticizer is used to reduce water in cement while keeping up a consistent workability. The percentage of replacement in cement is by 0% (control), 10% and also 10%, 20% and 30% with addition of 0.30% by weight of cement of superplasticizer. In order to achieve the objective, few tests were carried out including slump test, density test, water absorption test and compression test. The result of this research indicates that 10% of replacement of bottom ash with superplasticizer shows highest compressive strength with 33.215 MPa with density 2417 kg/m3, water absorption of 1.41% and 122 mm for slump loss at 28 days. This study proved that the addition of superplasticizer can increase the workability and strength of concrete containing bottom ash as replacement for cement.
The Impact of Various Soil Proportions Towards the Strength of Interlocking Compressed Earth Brick
Authors: Tonduba Y W , Mirasa A K , Asrah H
Published: June 2020

An interlocking compressed earth brick (ICEB) is a dry-stacked masonry brick with a similar production process to the Compressed Earth Brick (CEB). ICEB mainly consists of clay soil, sand, ordinary Portland cement (OPC) and water. This paper studies the properties of a combined soil (clay soil and sand), which affects the optimum moisture content (OMC) of the mixture and compressive strength of the produced specimens. There are five types of combined soils with mixture ratios of clay(C) soil to sand (S) of C55:S45, C50:S50, C45:S55, C40:S60, C35:S65 and C30:S70. Every mixture ratio shows a different OMC and varies in its compressive strength. The combination soil ratio of C45:S55, which means 45% of clay soil + 55% of sand, produced the highest compressive strength. The compressive strength increases as the clay content decreases and sand content increases. However, as the clay soil content decreased to lower than 45%, the compressive strength starts to decrease. It is due to the lack of plasticity properties from the clay which are responsible for bonding the material particles.
Influence of rice husk ash (RHA) on performance of green concrete roof tile in application of green building
Authors: Muhamad K , Zainol N Z , Yahya N , Noor S N A M , Hashim N H , Shahrazi D Z
Published: June 2020

This paper studies on the development of green concrete roof tiles by using rice husk ash (RHA) as a partial replacement of cement as a green material. Rice husk is a product of agricultural waste that can be found easily and in large quantities due to increased annual paddy production in Malaysia. Demand for cement in construction has increased over the years as a result of over dependence on the modern building materials, which are so expensive that low income earners cannot afford building houses of their own. Besides, the satisfaction of building users is closely related to thermal comfort which is a complex dynamics of temperature and humidity. In this study, cement was replaced by the RHA at 0% until 20% by weight. Roof tiles performance were assessed based on Malaysian Standard (MS) requirement comprised of transverse strength, water absorption and water permeability. Results show that up to 10% of RHA give a good performance of concrete roof tiles which comply with Malaysia Standard.
Ductility and energy dissipation of perforated steel plate shear walls
Authors: Abd Samat R , Tahir D , Fadzil A B , Abu Bakar S
Published: June 2020

Steel plate shear wall (SPSW) that consists of boundary elements and steel plate, has been used as a structural system to resist lateral loads such as strong wind and earthquake. The capability of SPSW to resist a relatively strong earthquake has been tested in an actual earthquake when a 35-story high rise building that employed SPSW stood still during 1995 Kobe earthquake while a nearby building collapsed during the catastrophe. The need for serviceability such as piping, duct for air conditioning, heating and ventilation as well as passageway requires SPSW to be perforated. Despite the expanding research on SPSW, there is a scarcity in the research on the effect of perforations on the performance of the SPSW. The objective of this research is to determine how openings of different sizes and orientations influence energy dissipation, shear load capacity, and ductility ratio of SPSW. Earthquake resistant building must have adequate energy dissipation capacity and ductility. Analysis was carried out on six SPSW models where three of them were denoted as Model A series. These models differ in the area of the openings. The rest of the models were denoted as Model B series which have the exact area of perforation, but different orientation. In both series, ASTM A36 steel was used for the plate and ASTM A992 steel was used for the boundary elements. The results were obtained with the aid of ABAQUS software application. Lateral loads were allowed in a cyclic orientation applied to a single side of the structure following the protocols of ATC 24. It is concluded that certain sizes of openings enhance the energy dissipation and ductility ratio. Model B3 which has the smallest dimension of the opening perpendicular to the load has the largest energy dissipation and shear load capacity but, has the smallest ductility.
Shear behaviour of 0.6 % and 0.7 % steel fibre reinforced concrete beams without stirrups
Authors: Lim J H , Lim S K , Mahzabin M S , Lee Y L , Yew M K , Ng C W
Published: June 2020

Concrete is a brittle material and respectively weak in tensile strength and tensile strain. Concrete technology is applied at which concrete is reinforced with steel fibre, as known as steel fibre reinforced concrete (SFRC) to produce a versatile structural material to exhibit superior strength properties in terms of ductility, fracture energy, toughness, strength and durability. The introduction of short, discontinuous and randomly oriented steel fibres into conventional concrete mixes possesses a strong bond with the concrete matrix with high elastic modulus. The goal of this study is to create a standard foresight in determining the potentiality of steel fibre as secondary shear reinforcement to partially or fully replace shear stirrups in conventional concrete. For this purpose, the series of SFRC beam specimens without stirrups which have the same concrete mixing ratios were produced with the inclusion of 0.6 % and 0.7 % steel fibre by volume fractions and compared with conventional normal weight reinforced concrete (NWRC) beam with stirrups. After the beam specimens had attained the target concrete characteristic strength of C25/30, four-point bending test was conducted to investigate the shear behaviour of reinforced concrete beams. The structural performance of shear beams was evaluated in the response of load-deflection, load-steel strain, crack patterns and failure modes. Test results indicated that with incorporation of steel fibres, the compressive strength and splitting tensile strength were improved, ultimate shear strength was improved up to 36 % at addition of 0.7 % steel fibre content, but water absorption was reduced. Besides, NWRC beam with stirrup increased 43 % in ultimate shear strength which possessed better performance in ductility.
An overview of the transportation issues in Kota Kinabalu, Sabah
Authors: Besar S N A , Ladin M A , Harith N S H , Bolong N , Saad I , Taha N
Published: June 2020

The explosive growth of population in Sabah has caused the rise of private vehicle ownership and utilizations which give significant defects on transportation and environmental conditions, especially in the central city of Sabah, Kota Kinabalu. As the demand in transportation increased, traffic congestion occurs due to the abundance of a private vehicle on the road while the improvement of traffic facilities is weak and slow. Traffic congestion is an urban mobility problem that worsens traffic flow and eventually, causing economic hindrance to happen. In order to overcome this problem, a good plan, systematic and safe transportation system should be developed. Hence, the purpose of this paper is to study and understand the transportation system in Kota Kinabalu and the feasibility of existing transportation plans for Kota Kinabalu. This paper outlines an overview of the existing transportation system available in Kota Kinabalu, Sabah, the issues encountered, as well as the impacts regarding the current city transport system. In summary, urban transportation relies on proper planning by experts based on passenger experience to find proper solutions to complex urban transport issues in Kota Kinabalu.
The effects of microclimate and air-infiltration on energy and long-term thermal comfort in high-rise buildings in tropical climate
Authors: Roslan N H , Ismail M R , Ahamed Hassain Malim N H
Published: June 2020

An increase in the number of high-rise buildings in most developing cities affects the surrounding microclimate. In this study, the influence of microclimate due to height variations and air infiltration were investigated for a building’s energy and long-term thermal comfort performances. A 20-storey high-rise office building with full glass façade in a hot and humid climate of Malaysia was studied using EnergyPlus to simulate the energy performance and RStudio programme for thermal comfort performance analysis. It was found that the building energy consumption reduced up to 2% when the air infiltration was removed from the building. However, the effect of microclimate showed insignificant reduction in energy consumption, but it had a significant difference in discomfort hours up to 17%. Air infiltration had less effect on thermal comfort with only 3 % reduction in discomfort hours. Microclimate should be considered to accurately evaluate the building performances in the densely built with high-rise buildings area. Removal of air infiltration from space helped in providing comfort and at the same time reduced the building energy consumption.
Enhanced carbon dioxide adsorption by amine-modified KCC-1
Authors: Nasir M S R M , Khairunnisa M P , Jusoh N W C , Jalil A A
Published: June 2020

The increase of carbon dioxide (CO2) emission due to anthropogenic activities has become a threat to our environment. Hence there is an urgent need to control its emission via carbon capture and storage (CCS) strategy. However, the readily available method, which is liquid amine absorption, possesses some drawbacks including being energy intensive and may cause material corrosion. Dry CO2 adsorption using amine-functionalized silica has been studied to provide a simple and cost-effective alternative for CO2 capture. Recently emerged dendritic fibrous silica possesses excellent morphology and characteristics to be developed as an effective CO2 adsorbent. Herein, the CO2 adsorption performance using amine-modified fibrous silica nanoparticle, KCC-1 was studied. As-synthesized KCC-1 was modified with tetraethylenepentamine (TEPA) via impregnation method. Its characteristics were studied before it was subjected to the CO2 adsorption experiment. The Fourier Transform Infra-red (FTIR) results indicates that TEPA was successfully impregnated with peaks at 3383 cm−1, 2935 cm−1, 2837 cm−1, 1558 cm−1, 1479 cm−1 and 1309 cm−1, while X-ray diffraction (XRD) analysis showed that KCC-1 structure was preserved. KCC-1/TEPA recorded higher adsorption capacity of CO2 compared to the unmodified KCC-1, with maximum adsorption capacity of 189.86 mg/g. Equilibrium isotherm model fitting of the CO2 adsorption was also carried out, and the adsorption data of KCC-1/TEPA fitted well to Toth isotherm. Overall, it has been demonstrated that KCC-1/TEPA has excellent potential to be used for CO2 adsorption, and more studies need to be conducted for its development.
The use of treatment train for stormwater quality control in urban areas in Malaysia: A short review
Authors: Osman M , Takaijudin H , Yusof K W , Goh H W , Ghani A Ab
Published: June 2020

Water pollution is a major challenge in urban areas. The main source of water pollution is the runoff accelerated from impervious areas and agricultural land. In recent years, planning and designing of urban water management in Malaysia is moving away from the conventional thinking of designing for flooding to balancing the impact of urban drainage on flood control and quality management. In order to minimize the environmental impact of water pollution, Best management practices (BMPs) and Low impact development (LID) approaches have been used to manage runoff as close as possible to its source. The individual practices often have a low ability to provide consistent pollutant removal. Therefore, the arrangement of several LID-BMPs is recommended. This arrangement in series is called a treatment train. There is a need to review findings in the use of treatment train for water quality control. Therefore, this review paper discussing the ability of the treatment train for water quality control of runoff in urban areas in Malaysia. In addition, it compares a single treatment with the treatment train. The use of treatment train was very effective for stormwater control when compared with a single treatment practice. However, the use of treatment train for treating other types of runoff such as agricultural runoff still not implemented yet. It is recommended to use this system for treating other types of runoff such as agricultural runoff in the future work.
Removal of ammonia from municipal solid waste (MSW) landfill using hydrated lime
Authors: Tengku Izhar Tengku Nuraiti , Chua J S , Hwidi Rajeb Salem , Mohd Saad Farah Naemah , Zakarya Irnis Azura
Published: June 2020

Leachate is known as a vigorous wastewater in terms of its organic matter and ammonia content. It is a major problem for municipal solid waste (MSW) landfill. It posed threat to surface water and groundwater. This study focusing on the removal of ammonia-nitrogen (NH3-N) by coagulation on a raw leachate sample taken from Rimba Mas municipal solid waste (MSW) landfill. The landfill leachate is tested for COD, colour and NH3N. Morphological features of calcium oxide are studied using XRF and SEM. Optimum dosage of coagulant for ammonia nitrogen removal from MSW leachate is investigated. The method used in this research was coagulant-flocculation treatment: jar test apparatus. The coagulant was conducted using hydrated lime, Ca(OH)2 with varying amount of coagulant to find the optimum dosage for ammonia nitrogen removal. A raw leachate sample taken from Rimba Mas landfill was treated with a different amount of hydrated lime (2, 4, 6, 8, 10 g/L) and 0 as a control to investigate the removal of ammonia nitrogen. The results showed that the pH of leachate (9.09) after treated with hydrated lime is increased when the dosage of hydrated lime is increased. Results showed that the best value of removal efficiency from leachate of colour, COD and NH3N were 54.70%, 56.22% and 85.25% respectively. We can conclude that as the optimum dosage increases, removal efficiency is increases.
Assessment of drinking water quality in water distribution system at new and old residential area at Kangar, Perlis
Authors: Mohd Sabri S N A , Wan Ahmad W A A , Kamarudzaman A N , Jalil M F Ab
Published: June 2020

Clean and safe drinking water is fundamental for human. Contaminated water can cause a vector of disease transmission and human health problem unless it is safe to drink. Although, a lot of technology developed to enhance the protected consuming water quality, water distribution system can adversely have an effect on the drinking water quality before it supplied to consumers. The aim of this study is to assess the physical and chemical parameters of drinking water quality in water distribution system at the old and new residential area in Kangar, Perlis. The water samples from tap water of old and new residential areas were collected and analysed for physical parameters (turbidity and colour) and chemical parameters (pH, free chlorine and ammoniacal nitrogen). From the findings, all the parameters tested complied to the limits set in the guidelines of the World Health Organization (WHO) and National Water Quality Standards of Malaysia.
The relationship between land use and marine litter at Kuala Perlis coastal area
Authors: Odli Z S M , Abdullah A L , Saad F N M , Fadzillah N S A
Published: June 2020

Abundance of litter exist in our ocean are listed among the crucial threat to the biodiversity that caused a particular concern due to the abundance, durability and persistence in the coastal environment since the area is highly productive. This research paper is to focus on coastal pollution with the objectives of identifying marine litter to relate with the land use in Kuala Perlis, Malaysia. Marine litter is collected at three points along the shoreline stretching 30 meters in length and 5 meters in width. Collected litter varied between categories and the highest amount was plastic weighing 53.15 kg/m2 followed by fabric, wood, glass, rubber and metal. Generally, there are significant relationship between land use and accumulation of marine debris. As there is a development in the area, the accumulation of marine debris increases, in contrast with the small amount of debris found in undeveloped or nonpopulated areas. The accuracy assessment obtained from Landsat 8 year 2014 and 2018 and Kappa statistics shows value range from 0.7 to 0.9 which indicate good classification performance using ERDAS Imagine 2015. Slight changes in urban development, cultivation area and forest with 1 % while for the water bodies and unclassified or cloud with 9% and 8 %.
Spatiotemporal analysis of seasonal SPEI in Peninsular Malaysia
Authors: Fung Kit Fai , Huang Yuk Feng , Koo Chai Hoon
Published: June 2020

Precipitation prevails in Peninsular Malaysia throughout the year. However, the extremity and inconsistencies in the pattern and intensity of precipitation also subject Malaysia vulnerable to droughts and dry spells. There are two main factors affecting the climate pattern in Peninsular Malaysia, namely the Northeast Monsoon and the Southwest Monsoon. Therefore, it is important to monitor the climate pattern in these periods to offer better drought prediction in Peninsular Malaysia. The Standardized Precipitation Evapotranspiration Index (SPEI), an index that considers both precipitation and temperature variables was adopted in the study. Seasonal SPEIs were built for the periods of the Northeast Monsoon (SPEI-NEM), the first inter-monsoon (SPEI-Inter1), the Southwest Monsoon (SPEI-SWM) and the second inter-monsoon (SPEI-Inter2) to represent the drought severity during these four periods. 133 precipitation and 28 temperature stations with availability of data from year 1983 to 2017 (35 years) were used to construct the seasonal SPEIs for whole Peninsular Malaysia. The number of dry seasons identified by the indices were first been tested to investigate the linear trend of seasonal drought occurrence in each region. Then, severity represented by the indices were spatially interpolated over Peninsular Malaysia to produce an overview of the changes of moisture condition over distance. Trend analyses using the Mann-Kendall trend test and the Sen’s Slope were also carried out on the drought index series. The results showed that the occurrence of seasonal droughts had increase throughout the years investigated. The spatial interpolation of drought severities also showed dissimilar variation among the seasons but justifiable on the premise of climatic change caused by monsoon winds and the topography of the study area. Thereafter, the spatial analysis of seasonal drought trend has also been carried out where the SWM season was found to be the most drought vulnerable season in the future, with the Southern region being the most vulnerable as its trend tests showed increasing drought trend regardless of the season period. These suggest that the water resources planning in the future should focus more on the two mentioned aspects for sustainable water supply.
Distribution of rainfall events in northern region of Peninsular Malaysia
Authors: Alang Othman M , Ghani A A , Alang Othman M S
Published: June 2020

Understanding of rainfall characteristics is important in designing Best Management Practices (BMPs) facilities. Because of intermittent rainfall, many researches on hydrology employ the concept of rainfall events. The selection of appropriate rainfall events for treatment design is essential to ensure the effectiveness of BMPs systems. Thus, the objective of this study is to identify the distribution of rainfall event using 6-hour Minimum Inter Event Time (MIT) and to identify the extreme rainfall thresholds over the study area. It shows that the rainfall data series consist of a large number of small events and rainfall depth of less than 2.5 mm (Type 1) contributes the highest percentage toward the overall record. About 63% of the rainfall record consists of Type 2 rainfall depth between 2.6 mm to 80 mm and only 1.3% recorded for rainfall event Type 3 with a depth exceeding 80 mm. It was found that the extreme rainfall threshold in Northern region of Peninsular Malaysia vary from 45 mm to 80 mm for R95 indices and 72 mm to 175 mm for R99 indices. These findings could be used as reference for better BMPs facilities design with extreme rainfall adaptation strategies.
Effect of indoor fine particulate matter (PM2.5) associated in Petaling Jaya LRTs
Authors: Suvennie S , Nordin S
Published: June 2020

This study was conducted to determine indoor PM2.5 concentration, which was measured at indoor settings in three different Light Rail Transits in Petaling Jaya. The selected locations were LRT Kelana Jaya, LRT Ara Damansara and LRT Glenmarie. This study focused on determining the indoor fine particulate matter (PM2.5) associated with samples collected from the three LRTs using Model 8532 DustTrakTM II Aerosol Monitor (DustTrak) at each LRT from 19:00 to 21:00 three times in a month from July till October 2018. Total of 33 mass concentrations were collected and 176 respondents were recorded from questionnaire given with information on health which was adapted from The American Thoracic Society, “Questionnaire ATS-DLD-C WHO (1982)”. Results were analyzed and compared with US Environmental Protection Agencies (EPA) and World Health Organization (WHO) standards and guidelines. LRT Glenmarie (37.64 µg/m3) was determined higher than US EPA (35 µg/m3) and WHO (25 µg/m3). More than 50% of the survey respondents were affected from the respiratory disease. Therefore, it is necessary to improve the ventilation in LRTs in order to provide a healthier indoor environment.
Active cool roof system for attic temperature reduction
Authors: Yew M C , Yew M K , Saw L H , Beh J H
Published: June 2020

The purpose of this project is to investigate the active cool roof system for the attic temperature reduction by using harvested rainwater system. A small scale metal roof model was designed and constructed to evaluate the attic temperature cooling performance. The measurements of the roof model were carried out indoor by utilizing the halogen lamp as the replacement for solar irradiation provided by sun. The surrounding ambient temperature was controlled to be around 25°C for the experimental. The rainwater harvesting system was implemented to cool down the roof top temperature that reduces the rate of heat transfer from the roof top to the attic region. The thermostat was installed with the water pump to reduce the roof top temperature efficiently. The hot water temperature of the heated roof was absorbed by the cool water and transferring into the small model of cooling tower and water collection tank. The result of the eco-friendly cool roof system has effectively reduced the attic temperature by 6.4 °C as compared to the conventional metal roof. The positive results of the integrated cool roof design have the ability to enhance the comfort of building occupants with sustainable renewable energy.
Optimization of hydrolysis and acidogenesis of food waste for production of organic acid
Authors: Zulkifli M A , Ong M Y , Nomanbhay S , Shamsuddin A H
Published: June 2020

The rising of human population in the world leads to the increasing number of food waste annually. To counter this problem, the food waste is suggested to be recycled into value-added product. Anaerobic digestion is one of the ways to recycle the food waste. The main product of a complete anaerobic digestion is methane (biogas). However, methane is very hard to handle since it is in gas form. Hence, this paper has drawn the attention toward the intermediate product of anaerobic digestion, the lactic acid. This paper presents the effect of 3 different variables: (a) pH values, (b) temperature and (c) amount of inoculum, on the hydrolysis and acidogenesis stages of anaerobic digestion of food waste. Besides, the optimal condition was determined. Experimental results show that the optimum, 0.0845 g/mL of lactic acid was obtained at pH value of 7, with 125 g of volatile solid food waste and 100 g of inoculum (Ragi Tapai), and was left in a pre-heated oven at 45°C for four days. This value was higher than the other previous study, and so showing promise in producing green acid from food waste that can be used as an intermediate substance for making other materials.
Aerosols characterization using satellite and ground based remote sensing during June 2013 haze episode over southern Peninsular Malaysia
Authors: Latiff Nur Atiqah Aainaa Abd , Machimura Takashi
Published: June 2020

Population and economic growth over the Southeast Asia region had triggered to the increasing of pollutant that been released by automotive emission, industrial activity or biomass burning. The occurrence of intense haze episodes become severe in every year degrading the surrounding air quality and reduce visibility which may cause economic loses. However, detailed study on the aerosols concentration, source and its properties remain a challenge due to the limitation of in-situ data. Therefore, this study aimed to analyse the aerosols properties over Southern Peninsular Malaysia by utilizing the satellite and ground based remote sensing. Thus, by emphasizing on 2013 intense haze episode, PM10 concentration combine with aerosols from Aerosol Robotic Network (AERONET) data and some environmental parameters, i.e. rainfall, visibility, and hotspot numbers were investigated. Southern Peninsular Malaysia experience a dry and dense condition in June 2013 with highest temperature with less rainfall were recorded. The aerosols concentration and properties through aerosol optical depth (AOD), Angstrom Exponent (AE) parameter and particle size distribut ion indicate the presence of fine aerosols during the June 2013 haze episode, which is associates with biomass burning aerosols. Meanwhile, the MODIS fire activity data represents more than 3000 hotspots were recorded over Sumatera region. HYSPLIT modelling shows the pollutant substance from biomass burning were transported to the study area on 21st of June 2013 from southwest area which mainly from the Sumatera area.
Study on Energy Consumption Structure of Guangdong Transportation Sector
Authors: Chen Hui , Yang Xi , Zhao Shasha , Wang Gang , Xie Wenli , Li Pei
Published: June 2020

Transportation energy is an important component of energy consumption. The research on the energy consumption structure of Guangdong Province’s transportation energy will help to predict the space for energy development, formulate energy development strategies and energy plans. At the same time, it also provides a scientific basis for China Southern Power Grid Corporation to realize the transformation of enterprise and energy. This paper uses the GCAM model, a bottom-up method, to study the trend of Guangdong’s transportation energy consumption structure by combining transportation technology, transportation mode, and transportation demand forecasting methods. It is found that the growth rate of transportation energy in Guangdong will slow down and decline after reaching the peak. Electricity consumption will become a major part of transportation energy consumption, and passenger turnover and cargo turnover will gradually increase.
Screening of Homogeneous CWAO Catalysts for Treatment of Ceramic Printing Waste-Water
Authors: Zhang Honghua , Zeng Qinglang , Wang Junfei , Shi Liang , Zhang Yongli
Published: June 2020

The ceramic printing and dyeing waste-water was treated by catalytic wet oxidation. The catalytic oxidation reaction was carried out under the conditions of 50 mg/L metal ion concentration, 180 °C of reaction temperature, 2.5 MPa of oxygen partial pressure and 500 rpm of stirring speed, and the time of catalytic oxidation was set at 90 min. Comparing the effect of structural auxiliaries and blank group on COD removal rate of effluent, the structural auxiliaries have no effect on effluent, that is, no catalytic effect; Comparing the blank group without adding catalyst, the copper nitrate has the highest cod removal rate of 72.5% for waste-water, so it can be used as the best homogeneous catalyst to treat waste-water. The order of catalytic effect from high to low is: Cu(NO3)2 > CuSO4 > Fe(NO3)3 > Fe2(SO4)3 > Co(NO3)2 > Cr(NO3)3 > Ni(NO3)2 > AgNO3 > Zr(NO3)4. Among the nine types of homogeneous catalysts, the most effective Cu(NO3)2•H2O catalyst treated the ceramic printing and dyeing waste-water, the COD decreased from 3775 mg/L to 1038 mg/L and the COD removal rate reached 72.5%, when the catalyst was not added under the same operating conditions. The COD removal rate of water samples was increased by 32.9%.
Design of 3D Simulation System for Natural Ignition Law in Gob Area of Multi-source and Multi-sink
Authors: Wang Qing , Li Weilong , zhang Canming
Published: June 2020

In order to comprehend the law of spontaneous combustion in “multi-source and multi-sink” goaf of coal mine, and to provide the basis for the prediction of early fire in goaf, the division of three zones of spontaneous combustion in goaf and the formulation of technical measures for fire prevention and extinguishing, a three-dimensional simulation system of spontaneous combustion law in goaf of “multi-source and multi-sink” coal mine is designed in this paper. The system uses energy conservation equation, Fick‘s law and mass conservation law to establish multi-source and multi-sink goaf flow field, oxygen concentration field, gas temperature field and caving coal and rock temperature field coupled mathematical model. The model is solved and programmed by using VB language mathematical model, which realizes the visual display of simulation results. The system is used to simulate the II929 mined-out area of Luling Mine, and good application results are obtained. The system has good operability and improves the calculation efficiency. It provides theoretical support for the prevention and control of spontaneous combustion in goaf of “multi-source and multi-sink” working face.
Comparative Research of Different Dimension Reduction Methods Combined with RWR Network Smoothing in Single Cell RNA-seq Data
Authors: Xiao Xuesong , Ye Pengchao , Ye Wenbin , Ji Guoli
Published: June 2020

Single-cell RNA sequencing (scRNA-seq) has been an important inspiration for the study of biomolecules through its reveal of cell heterogeneity. However, due to the low capture efficiency and frequent drop-out events in the single-cell sequencing process, the scRNA-seq data often has high sparsity and random missing values, which brings great difficulties to the subsequent analysis. The network propagation method based on random walk with restart (RWR) effectively fills in the missing values in the scRNA-seq data and reduces noise by referring to the prior information of gene interaction. Dimensionality reduction is also a commonly used pre-processing method for high-dimensional and sparse scRNA-seq data, which can be combined with the RWR-based data imputation to achieve noise reduction and feature extraction of scRNA-seq data. This article compares the performance of the commonly used single-cell data dimension reduction methods combined with the RWR network smoothing in different type of scRNA-seq data sets, and analyzes their applicability and stability.
Machine Learned Artificial Neural Networks Vs Linear Regression: A Case of Chinese Carbon Emissions
Authors: Sajid M J
Published: June 2020

China is the topmost source of world’s carbon emissions. Keeping this in view, a lot of work has focused on evaluating the relation between the Chinese carbon emissions and its drivers. However, these works mostly employ different types and extensions of the regression model to estimate the relations. The popular machine learning approaches like the artificial neural networks (ANN) are mostly overlooked in this regard. Furthermore, the studies based on the ANN and its different extensions often boast its superiority over the regression analysis. This claim has also not yet analysed for the relationship between a regions carbon emissions and their drivers. This study fills these critical research gaps. The results showed that the linear regression model with lesser ‘mean squared error’ outperformed the ANN model with linear activation code. This study can be a good starting reference for advanced future work on this much neglected research gap.
Analysis of the Main Controlling Factors of the Development Effect of a Single Well for Coalbed Methane
Authors: Zuo Yinqing , Xiao Qianhua , Wang Zhiyuan , Lu Xiuqin , Song Yang , Guo Wei , Zhang Lei
Published: June 2020

To determine the main controlling factors of the coalbed methane (CBM) development effect, 64 production wells were selected from the Mabidong Block as the study objective. Three aspects of the main controlling factors that affect production were analyzed: the reservoir geological conditions, the engineering construction quality and the drainage and production system. In addition, two new parameters, i.e., the resource index and the desorption index, were defined to better evaluate the influence laws of geological conditions on production. This study indicates that the resource index, the desorption index and the master fracture density are well correlated to stable gas production. Furthermore, fracturing is an effective way to improve the CBM development effect, but it must be based on the presence of adequate resources. Finally, the drainage and production intensity is strongly correlated with production, and the optimum value of drainage and production intensity for the Mabidong Block is 6∼7 m/d.
The Analysis of Green Building System Based on BIM
Authors: Ji-Xiang Liao , Tang-Ming Jiang , Xing-Ye Liu
Published: June 2020

The construction industry plays a decisive role in promoting social progress. With the rapid development of social economy, the construction industry is rising rapidly. The introduction of BIM technology into China, helps to reduce the consumption of building energy resource and advance building energy conservation. The comprehensive evaluation and analysis of building energy consumption is carried out through BIM technology. Revit software is used to simulate building construction and improve construction management. Quality and safety are the priority in the process of engineering construction projects while maintaining environment-friendly and sustainable development is next to this. This paper analyzes the BIM technology usage about Green Building in a systemic way, such as visual BIM model, design error correction, pipeline synthesis, construction coordination, virtual reality and operation management. BIM provides analysis and management for the sustainable development of green buildings, and has great potential in promoting the development and innovation of green buildings.