bluuebunny/crossref_metadata_2025 huggingface dataset:
Joint Planning Method of Virtual Power Plant for Distributed Generation and Grid in AC-DC Medium and Low Voltage Distribution Network
Authors: Liu Bei , Shen Xu , Zhang Ruosong , Chen Haofei , Zhou Xiaohang
Published: July 2023

The high proportion of virtual power plants (VPPs) used for distributed generation may cause problems such as power fluctuations and voltage distribution. In contrast, AC/DC hybrid power grid has strong transmission capacity due to its power information transmission. However, Its power grid structure and the location and capacity of VPP have an impact on the consumption capacity of the system, and the relationship between them are closely coupled. In addition, Under different operation modes, power grids of different voltage levels also have great differences. Therefore, the cooperative planning of medium and low voltage AC and DC distribution networks can improve the transmission capacity of the power grid Further improve the ability of distribution network to consume distributed power, A method is proposed in this paper about siting and capacity determination and AC-DC distribution grid frame transformation planning for medium and low voltage systems. The upper-layer model mainly focuses on AC-DC transformation scheduling in the power grid, distributed node location in the access grid and transmission line transmission capacity, while the lower-layer model effectively communicates with the low-voltage system through information flow and changes the operation of the power grid to a certain extent.The results show that the distributed generation system can reduce the operation cost and improve the overall operation efficiency of the power grid.
A Marx generator based on thyristors triggered in a shock ionization wave mode
Authors: Shang Tianyi , Ren Linyuan , Wang Yanan , Ding Weidong
Published: July 2023

Recently, a new trigger mode of thyristor which is called
shock ionization wave mode is researched. Compared with the
conventional trigger mode, this trigger mode can turn on the
thyristor rather fast. In this mode, a trigger voltage with a high
amplitude and fast rising speed is applied at both ends of the
thyristor. Many single-tube conduction experiments are reported
while the conduction threshold of shock ionization wave mode has not
been investigated. Besides, the application of this trigger mode in
some pulse power topology remains blank which is useful for this
mode. In this paper, to explore the impact ionization wave mode
conduction threshold of commercial thyristor, fast front high
voltage nanosecond pulses are generated by avalanche tube Marx
circuit. Pulse signals of different amplitudes are realized through
the voltage division resistor. The impact ionization wave mode
trigger threshold for commercial thyristors is about 2500 V in
amplitude and 250 V/ns in voltage rising speed and the higher the
rated parameter of the thyristor, the higher the threshold. To
broaden the application of this mode, a novel Marx generator based
on thyristors is proposed. A four-stage Marx generator is
constructed and the amplitude of the output voltage can reach
1869 V.
Assessing the knowledge, attitude, and practice among UTHM community towards scheduled waste management in UTHM
Authors: Ramli Najib , Lei Choi Xiang , Hashim Nor Haslina , Hakim Muhammad Fadhli
Published: July 2023

Universiti Tun Hussein Onn Malaysia (UTHM) laboratory is the major source of scheduled waste (SW) production which impacts human health and the environment if it is not well-managed. Therefore, management of SW involves serious cooperation from all SW generators (SWG), from students to both academic and non-academic staff in an educational institution. The purpose of the research is to understand the current status of SWG’s knowledge, attitude, and practices (KAP) in managing SW generated from laboratories activities in UTHM. The data gathering tool was a questionnaire with 30 questions its reliability and validity were approved. The survey consists of four sections: demographic (5 questions), knowledge (10 questions), attitude (10 questions), and practice (10 questions) were set. Data were analysed by using SPSS software version 25 for descriptive statistics, frequencies, and Spearman correlation test. The KAP evaluation finding indicated a High-Level in scheduled waste management (SWM) knowledge among the UTHM community (

x
¯

= 8.73). However, their attitudes and practices were at a Moderate-Level with attitude (

x
¯

= 26.82) and practice (

x
¯

= 22.61). Positive but weak correlation between SWGs attitude and practices discovered (r = 0.315, p < 0.05). Therefore, guidance for institution’s SWM program should provide knowledge, attitude and practices to the students and staff by publishing articles, hands-on training, or any environmental-related program to raise their awareness and enhance their attitude and practices toward SWM program.
Determining environmental ethics, personal norm, knowledge, and waste separation behaviour among households
Authors: Nasir Syukrie Mohd , Shafii Haryati , Yassin Azlina Md
Published: July 2023

The behaviour of separation of waste at the source has been identified as one of the key elements towards sustainable waste management which aims to prevent pollution and ultimately preserve the environment. However, the rate of waste separation in Malaysia is still low. Environmental ethics, personal norm and knowledge on waste separation have been identified as among the internal factors influencing household waste separation behaviour. The study employed quantitative research design with online questionnaire as a method of data acquisition while the study population is households in landed properties in the district of Kluang, Johor. Results show that the level of waste separation behaviours, personal norm towards waste separation and knowledge on waste separation are moderate. The study also found that households are holding ecocentric and biocentric environmental ethics orientation, indicating a good sign for pro-environmental support and behaviours through the activation of personal norm. The findings of the study can be used by stakeholders in formulating policies, initiatives, programmes and strategies towards sustainable waste separation among households as part of the whole sustainable waste management system in the country.
Repas lama dam water quality and heavy metal contamination using Qual2k
Authors: Gunesegeran Kishan , Sofiyan Mohd , Rahman Nurharniza Abdul , Muodzi Taurai Leonard
Published: July 2023

Repas Lama Dam in Bentong Pahang has been experiencing pollution by Non-Point Sources (NPS) that can be found upstream of the Sungai Repas, the pollution being so evident that discoloration of the water is observable at the location. The area is littered with mines active and inactive, with many of the inactive mines being improperly shut down. When there are mining activities, some major waste or tailings are produced as the by-products of the process which drastically increases the amount of pollution that a water body that runs through these areas will contain. The Water Quality Parameters at a location, whether biological, chemical, or physical, can give a lot of insight into the level of pollution found in a water body. Through collecting these parameters and running them through a water quality model, it can give a lot of information on the present state of a river and help in attaining predictions of the health of a river. QUAL2K is the water quality model that was used to analyse the water at Old Repas Dam and further make predictions on the state of the river after 10 years. After the modelling process, the water quality parameters and the heavy metals present were analyzed using the Malaysian National Water Quality Standard (NWQS), which also assisted in classifying the water at Old Repas Dam based off individual parameters and its overall Water Quality Index score. The major water quality parameters that were used for this study are Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Ammonia Nitrogen, pH and Total Suspended Solids (TSS). In terms of heavy metal analysis, the heavy metals that were looked at are Arsenic (As), Lead (Pb), Zinc (Zn), Copper (Cu), Tin (Sn) and Aluminium (Al). The data for these parameters being collected from studies that were conducted on the site in 2021 and information given by the Department of Statistics Malaysia.
An overview on the potential dam hazard and pre-qualitative analysis on the selected critical dam in Malaysia
Authors: Hashim Syarifah Intan Najla Syed , Talib Siti Hidayah Abu , Abustan Muhammad Salleh
Published: July 2023

Apart from flood control and water storage for irrigation, dams were used for hydropower generation, navigation, drinking water supply, recreation and in mining operations as tailing dams. Human errors and mistakes have undermined safety in many dam operations, resulting in serious safety issues and numerous failures. Safety concerns were also largely caused by increased population and land use in dam downstream areas and by failing to perform necessary inspection, maintenance, or upgrade work. Dam safety cannot be concerned only with the structure itself, but it should be considered in relation to the population at risk in the downstream flood plain. Several potential dam hazards were listed in MyDAMS guidelines but for this research, the hazards chosen are overtopping and seepage failure considering the condition of Malaysian dam. Only one (1) selected dam will be chosen as the most critical dam. The selection criteria of the dam will be based on their type of dam, hazard classification, dam purpose and downstream population. A qualitative analysis was done by using the secondary data prepared by DID and hazard classification was done using dam hazard rating. Batu Dam was chosen as the most critical dam with high hazard rating as it has the highest crest elevation, water level and has the shortest distance between dam and populated area downstream.
Legal and institutional assessment at Kedah’s Shoreline, Malaysia: A study report
Authors: Abustan M S H , Razi M A M , Gheethi A A , Mahmud M , Maarrof M , Yusop Y M , Iberahim N
Published: July 2023

The present paper examines the existing legal framework and administrative instruments outlined and adopted by various agencies to promote the sustainable development of the coastal areas for public safety, the protection of coastal communities and properties along the coast, and protection of environment at Kedah’s shoreline. The study provides an insight on the various laws and regulations governing developments in the coastal areas. An integrated and coordinated approach was proposed for the application of reclamation projects. The process which involved 11 stages is commonly adopted model by various state and planning authorities in Malaysia. Hence, the coastal development management strategies including deep sea zone management, coastal sea zone management and municipal sea zone management was seen to be the effective mechanism for long-term sustainability of coastal area and resources as well as able to improve the life quality in the coastal region.
Recycled waste of construction industry in Malaysia: A review
Authors: Lee Jin Chai , Thedy Wijaya Hansen , Ng Jing Lin , Lee Samuel
Published: July 2023

The increasing demand in the construction industry has led to a vast development in recent years. However, the impacts of this development are arising such as the increasing amount of waste. The majority of construction solid waste is dumped in landfills despite of its recyclable potential. Therefore, there should be a more viable solution to answer this issue. The objective of literature review is to obtain the information of each kind of construction waste that is most recycled with the methods. The review is based on the articles related to the recycled waste issues in Malaysia. In terms of recycling methods, paper and cardboard waste is mostly recycled into new paper while asphalt waste does have potential as aggregates for new asphalt layer. Moreover, brick and glass waste which are commonly found in demolition can be turned into pozzolanic materials and filler or glass fibre respectively. Meanwhile, the metals waste may be recycled as new metals while plastic waste can be turned into other plastic products or composite. Lastly, the timber and concrete waste can be recycled as boards and concrete aggregates respectively. The recycling system of construction waste is regulated by several bodies in Malaysia: National Solid Waste Management Department, Solid Waste and Public Cleansing Management Corporation Malaysia (SWCorp), and Department of Environment Malaysia.
Feasibility study of fine-metakaolin and coal bottom ash as cement and fine aggregate replacement in seawater-mixed concrete
Authors: Yeng C L , Md Noor N , Che Rahim N A N , Ismail M H , Inam I
Published: July 2023

The combination effect of fine-metakaolin (FMK) and coal bottom ash (CBA) as cement and fine aggregate replacement in seawater-concrete was investigated to reduce environmental issues such as carbon emission, global warming, and insufficient water resource. Optimum percentages of 10%, 20% and 30% of fine-metakaolin was determined in Stage 1 through compression strength test. Stage 2 involved testing on mixture with FMK obtained in Stage 1 and 10%, 20%, 30%, 40% and 50% of CBA as the fine aggregate replacement. Nine series of concrete mixtures were prepared to conduct a compressive strength test and water absorption test at 7 and 28 days. It was observed that 10% of FMK and 10% of CBA incorporated with seawater had the highest compressive strength. Water absorption of the seawater-concrete mixed increased as the percentage of the CBA increased. It can be concluded that 10% to 50% replacement of CBA is suitable as the fine aggregate replacement with the substitution of FMK at 10%.
Determination of Basic Wind Speed for the Design of Buildings in Cambodia
Authors: Lin Chanthorn , Chhin Rattana , Han Virak , Doung Piseth
Published: July 2023

Basic wind speed is a very essential parameter used for conversion into wind loads on building structures. In Cambodia, the information on basic wind speed remains uncertain due to insufficient fundamental studies on the wind characteristics associated with regional climatic conditions. The aim of this paper is to assess and discuss the basic wind speeds for structural wind-resistant design in Cambodia by using statistical and probabilistic approaches. The datasets have been collected from National Centers for Environmental Information datasets, National Oceanic and Atmospheric Administration under World Meteorological Organization, and Mekong River Commission in forms of hourly wind speeds. The hourly wind speeds were then statically converted to 3-second gusts speeds using Gaussian Distribution Transformation. The extreme value distributions namely, Gumbel and Gringorten were used to analyze the extreme speed in accordance with a return period. The results showed that with a return period of 10 to 1000 years, the basic wind speed varies from a minimum of 22m/s to a maximum of 53m/s, respectively. These results provided a new aspect over traditionally uncertain basic wind speed selection and can be an alternative for the estimation of wind loads for the design of building structures in Cambodia.
Influence of distance between the first sensor and support in determining tension of fixed-end cable using multiple synchronized vibration measurement
Authors: Syamsi Muhammad Ibnu , Wang Chung-Yue , Nguyen Van-Son
Published: July 2023

Non-destructive evaluation has been developed to identify cable tension for any end-rotational stiffness condition. One of the existing methods uses multiple vibration measurements. This paper aims to study the effect of shifting the closest sensor to the support in multiple vibration measurements through numerical simulation. A cable fixed at both ends vibrates under artificial random excitation is simulated. Three cases of five synchronized signal recording arrangements are applied to the cable, where the distance from the support to the first recorder (d1) is different for each case. The distance d1 of Case 1, Case 2, and Case 3 are d, 2d, and 3d, respectively, where d is the distance between the recorder, and d is taken as 7% of the total length and the same for all cases. Cable dynamical properties are analyzed using a stochastic subspace identification method, and effective lengths are figured out by curve fitting. Under the same frequency range, seven effective lengths are obtained in Case 1, while eight are detected in Cases 2 and 3. Besides, it can be concluded that Case 1 generates larger errors in predicting tension compared to other cases.
Perception of motorcyclists on safe riding in Kota Kinabalu
Authors: Saibin M I , Yaacob H , Hassan S A , Mohamed A , Kamarudin S N N , Jaya R P , Al-Safar Z H , Shaffie E
Published: July 2023

Despite the high risks reflected from the annual road traffic casualties, motorcycles remain a popular mode of transport in Malaysia due to economic and ease-of-use factors. Therefore, various parties need to play their roles, make proper plans and take actions to accommodate the needs of the motorcyclists in Malaysia. Consequently, some fundamental basis on how motorcyclists interact with the road environment and other drivers was needed. For this reason, this study was to examine and assess motorcyclist perception towards safe riding regarding the road environments and other drivers’ attitude and behaviour. A survey by distributing questionnaires among motorcyclists in Kota Kinabalu, Sabah was conducted and was analysed using Statistical Package for Social Science (SPSS) tools. It found that most motorcyclists, regardless of their demographic and riding background, perceive that poor road conditions such as road surface defects and slippery roads highly affect their safe motorcycling. Besides that, there was no statistically significant difference between motorcyclists’ perceptions of positive and negative attitudes and behaviour. These findings also guide the development of any road safety initiatives and strategies, as well as for future studies specifically related to motorcycle concerns.
The evaluation of crumb rubber as a filler in asphalt mixture to against moisture sensitivity
Authors: Aman MY , Taher M N M , Shahadan Z , Rohani M M , Daniel DB , Bujang H , Ahmad Termida N , Arumugam TN
Published: July 2023

In Malaysia, road pavements are frequently damaged by the accumulation of water on the surface caused by heavy rain, due to the humid climate. The presence of water within the asphaltic concrete mixture particles may impede their workability. Exposure towards natural phenomenon such as rain can be the main cause related to the presence of water inside the asphalt pavements. To improve road conditions for users, it is necessary to consider alternative road pavement designs. This study proposes using rubber crumb as modifier as its water-impermeable characteristic will be able to enhance the performance of standard asphalt mixtures to reduce asphalt mixtures moisture sensitivity. Subsequently, the Marshall Mix Design method was utilized to conduct Indirect Tensile Strength tests in order to achieve the objectives of this study. A total of 16 samples were prepared for this study, comprising of standard asphaltic combinations as well as asphaltic mixtures with different percentages of crumb rubber (0%, 4%, 6%, and 8%) relative to the overall weight of the asphalt mixtures. In comparison to the typical way of asphaltic mixture, the sample that utilized crumb rubber as a modifier had a substantially greater value of strength based on the Indirect Tensile Strength Test results. As expected from the findings of the study, the presents of water in asphalt mixtures reduces the asphalt mixtures strength and workability. To conclude, incorporating crumb rubber in asphalt mixtures enhances their effectiveness in resisting moisture sensitivity.
Performance of coconut fiber as bitumen modifier in asphalt mixture influence to fatigue resistance
Authors: Zulkafli Azril Zafran , Yunus Khairul Nizam Mohd , Kamaruddin Nurul Hidayah Mohd , Suhandri H.F.
Published: July 2023

One of the most prevalent challenges faced in road construction is pavement distresses produced by ageing asphalt pavement, which resulted in fatigue cracking. Fatigue cracking is regarded as one of the primary failure types when the tension in the bituminous layer is low due to high vehicle traffic load repetition. The study focuses on evaluating the performance of coconut fiber as modifier in bitumen penetration grade 60/70. The addition of 0.5%, 0.75% and 1% were used in this study to determine the effect on asphalt mixture. Indirect tensile fatigue test were conducted to determine the life cycle of the sample. The result showed that the increasing percentage of coconut fiber will improve the bitumen physical properties and increased the life cycle of asphalt mixture. In this study, 1% coconut fiber produced the best result. In conclusion, the addition of coconut fiber into bitumen can improve the performance of asphalt mixture in term of fatigue resistance.
Stiffness evaluation of Forta Fibre Reinforced Asphalt Concrete (FRAC) mixture under different pulse repetition load
Authors: Taher M. N. M , Aman M. Y. , Bujang H. , Rusli H.
Published: July 2023

Pavement structure can be designed either as a flexible or a rigid pavement based on its structural behaviour, with flexible pavements being frequently favored due to its advantages. One of the major problems that normally occurred in road construction was pavement distresses due to the quality of the materials. Numerous studies were carried out to explore sustainable ways to improve the pavement performance especially on modification of the asphaltic concrete in construction phases. This paper investigates the effect of Forta-Fi fiber on stiffness performance of hot mix asphalt mixture (HMA). In this respect, conventional asphalt binder grade 60/70 and Nominal Maximum Aggregate Size (NMAS) 12.5mm were used in the preparation of asphalt mixture specimens as specified in Superpave mix design method. Performance of modified samples incorporating 0.3, 0.5 and 0.7% of total mixture were evaluated for resilient modulus accordance to ASTM D4123 using Universal Testing Machine (UTM). The samples were tested at 25°C and 40°C with pulse repetition period 1000ms, 2000ms and 3000ms to simulate low, medium and high volume of traffic. As a result, the resilient modulus values of modified asphalt mixture improved 38% with 0.3% additive of Forta-Fi at 25°C with 3000ms pulse repetition period, while at 40°C with 3000ms pulse repetition period improved 23% with 0.5% additive of Forta-Fi. Based on these studies, the addition of fibers reinforcement into the asphalt mixture has a significant effect on resilient modulus of fibers reinforced asphalt mixture.
Simulation of 2D ground movement due to tunnel excavation using Finite Element Method (FEM)
Authors: Yian Bong Jia , Talib Zaihasra Abu
Published: July 2023

Sustainability in construction of tunnel is very important to reduce environmental impact and also minimal use of earth resources. Therefore, numerical modelling is proposing at design stage to achieved this objective. To evaluate the changes in soil settlements during tunnel excavation, empirical, analytical, and numerical methods have been frequently applied movement research and the numerical method is effective in anticipating possible underground excavation scenarios. This paper describes the project on prediction of 2D ground movement due to the tunnel excavation by using Finite Element Method via ADONIS with the soil properties data from certain soil section of Goose Creek Tunnel project. The tunnel is in horse-shoe shape and typically be 1.8 m wide by 2.2 m tall. However, in this paper, the tunnel is assumed as a circular tunnel with diameter 2.2 m. This paper is focus on the effects of the constitutive soil models. The influence of type of soil model to the ground settlement is investigated and discussed. The simulation is confirmed by comparing the output of the settlement with manual calculation. The findings prove the Plastic Hardening (PH) model is more suitable in modelling ground movement due to tunnel excavation. By designing a tunnelling structure with a low prediction error, the engineers can build the most efficient tunnel.
The effects of coconut shell ash admixed with lime in variation to curing time for road construction
Authors: Ramli R. , Masari M. H. A. , Idrus J. , Mansor S. , Albar A.
Published: July 2023

Poor subgrade soil conditions might cause insufficient pavement support and shorten the life of the pavement. The addition of chemical or cementation additives to subgrade soils can help pavement to perform better. Chemical additives can be anything from waste to manufactured components like lime and coconut shell ash (CSA). These additives can be used to improve the qualities of a of soils. The efficiency of these additives is determined by the type of soil treated and the amount of additive used. Therefore, this research investigated the properties of expansive clay soil when stabilized by lime and CSA. The physical properties tests were carried out on the natural soil sample for identification and classification; and later, the mechanical properties tests were performed on the soil sample namely California Bearing Ratio (CBR). All the tests were performed in accordance to BS 1377 (1990). The soil sample was added with lime in a constant quantity of 6%, while CSA was added in proportions of 2%, 4%, 6%, and 8% from the total weigh of admixed sample. The constant lime percentage of 6% was used for stabilization as it recorded the highest CBR value during testing. The highest percentage of lime-CSA mixture was achieved at Variation 2 (6% lime + 4% CSA) for 4, 7, and 28 days as the highest value of soaked CBR was observed at this stage. Thus, it is proven that treating expansive soil with CSA combined with lime enhances it strength.
Peat soil improvement using cement and quarry dust
Authors: Jumien Nur Latifah , Talib Mohd Khaidir Abu , Yusoff Mohammad Nasrul Mohd , Wahab Norhaliza
Published: July 2023

Peat soil is one of the soil types available in Malaysia, which has a high compressibility and low shear strength. Thus, peat is considered inappropriate to support a construction site in its natural state. Among the methods suitable for the stabilization of peat soil is using a cement. However, the quantity of cement required in peat stabilization is quite large and made this method not too environmentally friendly due to carbon dioxide, CO2 emission from the cement production. Therefore, in this study, quarry dusts are used to partially substitute to ordinary Portland cement in peat soil stabilization. Quarry dusts were expected to potentially act as a pozzolan (containing cementitious properties to replace cement). Laboratory testing to determine the physical, chemical and mechanical properties were carried out to investigate the strength, acidity and the microstructure of the treated and untreated peat soil. For mechanical properties, Unconfined Compressive Strength test (UCS), was conducted to determine the peat soil strength., Chemical and microstructure (Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray (EDX)) tests were carried out to assess the mechanism of strength gain in the stabilized peat soil. The results obtained show that by partially replacing the cement with 5% quarry dust, the soil strength increases from 47 to 684 kN/m2, which suitable for low loading construction such as car park area and outdoor sport court. The microstructural results also show PC and PCQ5 increases the calcium, Ca and decreases the carbon dioxide, which has an effect on increasing strength and decreasing the soil acidity.
Home modifications to improve accessibility of children with Cerebral Palsy in Malaysia
Authors: Halimi N H , Nawawi N M , Aripin S
Published: July 2023

The physical environment in homes plays a crucial part in accessibility to persons with disabilities from all angles. This includes persons with cerebral palsy (CP), a common childhood disability that affects many children worldwide. Currently it is estimated that 2 to 3 babies in every 1000 births globally are born with CP due to the injury to the brain that occurred during pregnancy, birth, or early years of life. Subsequently, the physical environment of children with cerebral palsy is frequently inaccessible. The objective of this study is to identify to what extent modifications are made in existing homes to improve accessibility and promote independence in children with cerebral palsy. An online survey via Google Form was disseminated to parents of children with CP with Gross Motor Function Classification System (GMFCS) Levels II, III and IV. From a total of 41 participating respondents, only nine respondents reported they had made modifications in their homes to improve their child’s accessibility. Those who were unable to make modifications faced obstacles such as cost, the inability to make changes to rented property and lack of urgency. Many studies conclude that the accessibility of the physical environment in homes of children with cerebral palsy is essential for promoting children’s independence. The study also informed that the modification would assist other physical disabilities, such as the ageing population and individuals with physical impairments. Therefore, this study suggests additional design strategies to incorporate requirements for children with cerebral palsy into the existing Malaysian Standard (MS) 1184: 2014 – Universal Design and accessibility in the built environment – Code of Practice reference and more incentives from the government, such as financial assistance to help ease the burden of home modification for the physically disabled.
Effects of natural ventilation on indoor thermal comfort in a residential house constructed with reinforced concrete wall
Authors: Choong X Y , Zakaria M A , Yasin M N , Hanipah M H , Alexson L Y L , Lee Y H
Published: July 2023

This study aims to investigate the effect of natural ventilation on the thermal performance of a double-story end-lot unit residential house constructed with reinforced concrete walls and structure in Kluang, Johor. Field measurement was conducted in the master bedroom of the house. Five ventilation cases were investigated which are night ventilation (case 1), no ventilation (case 2), day ventilation (case 3), day ventilation with fan (case 4), and night ventilation with fan (case 5). The measured data were indoor air temperature, outdoor air temperature, indoor relative humidity, outdoor relative humidity, and globe temperature. Then, the thermal comfort assessment was conducted based on the adaptive thermal comfort equation for hot-humid climate for all cases. The results show that the mean indoor temperature for all cases is in the range of 29°C to 31.5°C which indicates a high indoor air temperature. Furthermore, the analysis of air temperature difference between outdoor and indoor (out-in) for different natural ventilation modes showed that the indoor thermal conditions of the master bedroom were not significantly different when compared between cases. In the thermal comfort assessment, the night ventilation case (case 1) provided the most comfortable hours during the measurement with a range of 11 to 35.4 %, thanks to the lower outdoor climate conditions at night compared to the other cases. Overall, in this study, the effect of natural ventilation modes on the indoor thermal condition of a master bedroom in a residential house with concrete walls and structures was found not significantly different in the performance of air temperature reduction and comfort hour improvement when compared between cases.
A thermal response in architecture: Case study (Malaysian residential)
Authors: Zulkeply N , Sidik Md Sidik , Chuen C C
Published: July 2023

This study aims to create an awareness of the indoor and outdoor thermal conditions of a design and how design influences the outcome of as a responsive design. The desirable and undesirable thermal conditions are considered, and an analysis of the cause-and-effect is discussed. While thermal conditions, and its cause-and-effect considerations may be directed to any building, achieving an ideal solution requires careful integration of thermal comfort principles. Refinement through the understanding of thermal comfort principles can achieve significant energy saving without necessarily sacrificing functionality or aesthetics. Precedent studies are being discussed to see the benefits and usage of the materials based on the intention of the design and the function of the space that would impact the indoor quality environment. Based of field observation, data collection and result analysis, solutions are proposed to two different local residential buildings. Key finding shows different design factors, materials and operative conditions can influence the thermal performances of buildings. This analysis may help to improve energy efficiency in built environment and to be used for further study in thermal response in architecture while investigating new ways to design building walls that could possibly be modularized in the future with both external and internal design considerations. This intention is to be further explored with first the basic understandings of layering of materials before the simulations into the spaces.
Study on characterization technology of porosity and fractal dimension of micro-arc oxidation coating
Authors: Wang Xiao-Fei , Zhang Tao , Li Ya-Li , Liu Wei-Wei , Chen Yu-Di , Wang Jia-Qi , Li Shuang
Published: July 2023

The porosity of the micro-arc oxidation coating of pure titanium was assessed through the utilization of Mercury intrusion porosimetry (MIP). The porosity values were subsequently adjusted by accounting for the proportion of coating volume, resulting in a more precise determination of the coating’s porosity. Additionally, the fractal dimension of the pore structure was determined through the application of a linear regression equation utilizing the Mercury intrusion data. The findings indicate that the observed numerical dispersion from image metohd is substantial, with a range of 34.9% between the minimum and maximum values. This suggests that the precision and validity of the porosity outcomes derived from this approach are inadequate; The MIP is capable of determining both the porosity, average pore size and pore size distribution of the sample, while also mitigating the impact of the matrix through test result correction, thereby yielding precise porosity values. Additionally, the results of the verification experiment demonstrate a positive correlation between the porosity alteration of the MIP and oxidation duration, thereby affirming the reliability of the test outcomes; Through the analysis of pressure, pore size, cumulative Mercury intrude volume, and incremental Mercury intrude volume data obtained from MIP, the fractal dimension of the coating’s pore structure then be determined. Research showed that as the oxidation time increases, the pore fractal dimension of the MAO coating gradually expands within a narrow range, from 2.57 and finally stabilized at 2.77, indicating a gradual increase in pore structure complexity.
Representation of single neuron dynamics using 1-D and 2-D Discrete dynamical systems
Authors: Zeki Mustafa , Kapçak Sinan
Published: July 2023

Biological neurons are typically modeled using the Hodgkin-Huxley formalism, which requires significant computational power to simulate. However, since realistic neural network models require thousands of synaptically coupled neurons, a faster approach is needed. Discrete dynamical systems are promising alternatives to continuous models, as they can simulate neuron activity in far fewer steps. Many existing discrete models are based on Poincaré-map-like approaches, which trace periodic activity at a cross section of the cycle. However, this approach is limited to periodic solutions. Biological neurons have many key properties beyond periodicity, such as the minimum applied current required for a resting cell to generate an action potential. To address these properties, we propose a discrete dynamical system model of a biological neuron that incorporates the threshold dynamics of the Hodgkin-Huxley model, the logarithmic relationship between applied current and frequency, modifications to relaxation oscillators, and spike-frequency adaptation in response to modulatory hyperpolarizing currents. It is important to note that several critical parameters are transferred from the continuous model to our proposed discrete dynamical system. These parameters include the membrane capacitance, leak conductance, and maximum conductance values for sodium and potassium ion channels, which are essential for accurately simulating the behavior of biological neurons. By incorporating these parameters into our model, we can ensure that it closely approximates the continuous model’s behavior, while also offering a more computationally efficient alternative for simulating neural networks.
Robust detection of marine life with label-free image feature learning and probability calibration
Authors: Schanz Tobias , Ove Möller Klas , Rühl Saskia , Greenberg David S
Published: July 2023

Advances in in situ marine life imaging have significantly increased the size and quality of available datasets, but automatic image analysis has not kept pace. Machine learning has shown promise for image processing, but its effectiveness is limited by several open challenges: the requirement for large expert-labeled training datasets, disagreement among experts, under-representation of various species and unreliable or overconfident predictions. To overcome these obstacles for automated underwater imaging, we combine and test recent developments in deep classifier networks and self-supervised feature learning. We use unlabeled images for pretraining deep neural networks to extract task-relevant image features, allowing learning algorithms to cope with scarcity in expert labels, and carefully evaluate performance in subsequent label-based tasks. Performance on rare classes is improved by applying data rebalancing together with a Bayesian correction to avoid biasing inferred in situ class frequencies. A divergence-based loss allows training on multiple, conflicting labels for the same image, leading to better estimates of uncertainty which we quantify with a novel accuracy measure. Together, these techniques can reduce the required label counts ∼100-fold while maintaining the accuracy of standard supervised training, shorten training time, cope with expert disagreement and reduce overconfidence.
Tunneling magnetoresistance materials and devices for neuromorphic computing
Authors: Yao Yuxuan , Cheng Houyi , Zhang Boyu , Yin Jialiang , Zhu Daoqian , Cai Wenlong , Li Sai , Zhao Weisheng
Published: July 2023

Artificial intelligence has become indispensable in modern life, but its energy consumption has become a significant concern due to its huge storage and computational demands. Artificial intelligence algorithms are mainly based on deep learning algorithms, relying on the backpropagation of convolutional neural networks or binary neural networks. While these algorithms aim to simulate the learning process of the human brain, their low bio-fidelity and the separation of storage and computing units lead to significant energy consumption. The human brain is a remarkable computing machine with extraordinary capabilities for recognizing and processing complex information while consuming very low power. Tunneling magnetoresistance (TMR)-based devices, namely magnetic tunnel junctions (MTJs), have great advantages in simulating the behavior of biological synapses and neurons. This is not only because MTJs can simulate biological behavior such as spike-timing dependence plasticity and leaky integrate-fire, but also because MTJs have intrinsic stochastic and oscillatory properties. These characteristics improve MTJs’ bio-fidelity and reduce their power consumption. MTJs also possess advantages such as ultrafast dynamics and non-volatile properties, making them widely utilized in the field of neuromorphic computing in recent years. We conducted a comprehensive review of the development history and underlying principles of TMR, including a detailed introduction to the material and magnetic properties of MTJs and their temperature dependence. We also explored various writing methods of MTJs and their potential applications. Furthermore, we provided a thorough analysis of the characteristics and potential applications of different types of MTJs for neuromorphic computing. TMR-based devices have demonstrated promising potential for broad application in neuromorphic computing, particularly in the development of spiking neural networks. Their ability to perform on-chip learning with ultra-low power consumption makes them an exciting prospect for future advances in the era of the internet of things.
Expanding the potential of biosensors: a review on organic field effect transistor (OFET) and organic electrochemical transistor (OECT) biosensors
Authors: Niu Yue , Qin Ze , Zhang Ying , Chen Chao , Liu Sha , Chen Hu
Published: July 2023

Organic electronics have gained significant attention in the field of biosensors owing to their immense potential for economical, lightweight, and adaptable sensing devices. This review explores the potential of organic electronics-based biosensors as a revolutionary technology for biosensing applications. The focus is on two types of organic biosensors: organic field effect transistor (OFET) and organic electrochemical transistor (OECT) biosensors. OFET biosensors have found extensive application in glucose, DNA, enzyme, ion, and gas sensing applications, but suffer from limitations related to low sensitivity and selectivity. On the other hand, OECT biosensors have shown superior performance in sensitivity, selectivity, and signal-to-noise ratio, owing to their unique mechanism of operation, which involves the modulation of electrolyte concentration to regulate the conductivity of the active layer. Recent advancements in OECT biosensors have demonstrated their potential for biomedical and environmental sensing, including the detection of neurotransmitters, bacteria, and heavy metals. Overall, the future directions of OFET and OECT biosensors involve overcoming these challenges and developing advanced devices with improved sensitivity, selectivity, reproducibility, and stability. The potential applications span diverse fields including human health, food analysis, and environment monitoring. Continued research and development in organic biosensors hold great promise for significant advancements in sensing technology, opening up new possibilities for biomedical and environmental applications.
Review of regulating Zn2+ solvation structures in aqueous zinc-ion batteries
Authors: Zhang Wanyao , Chen Yufang , Gao Hongjing , Xie Wei , Gao Peng , Zheng Chunman , Xiao Peitao
Published: July 2023

Aqueous zinc-ion batteries, due to their high power density, intrinsic safety, low cost, and environmental benign, have attracted tremendous attentions recently. However, their application is severely plagued by the inferior energy density and short cycling life, which was mainly ascribed to zinc dendrites, and interfacial side reactions, narrow potential window induced by water decomposition, all of which are highly related with the Zn2+ solvation structures in the aqueous electrolytes. Therefore, in this review, we comprehensively summarized the recent development of strategies of regulating Zn2+ solvation structures, specially, the effect of zinc salts, nonaqueous co-solvents, and functional additives on the Zn2+ solvation structures and the corresponding electrochemical performance of aqueous zinc-ion batteries. Moreover, future perspectives focused on the challenges and possible solutions for design and commercialization of aqueous electrolytes with unique solvation structures are provided.
Instrumental Variable Analysis of Racial Discrimination and Blood Pressure in a Sample of Young Adults
Authors: Lawrence Jourdyn A , Kawachi Ichiro , White Kellee , Bassett Mary T , Williams David R
Published: July 2023

Racial inequities in blood pressure levels have been extensively documented. Experiences of racial discrimination could explain some of this disparity, although findings from previous studies have been inconsistent. To address limitations of prior literature, including measurement error, we implemented instrumental variable analysis to assess the relationship between racial discrimination in institutional settings and blood pressure. Using data from 3,876 Black and White adults with an average age of 32 years from examination 4 (1992–1993) of the Coronary Artery Risk Development in Young Adults Study, our primary analysis examined the relationship between self-reported experiences of racial discrimination in institutional settings and blood pressure using reflectance meter measurement of skin color as an instrument. Findings suggested that an increase in experiences of racial discrimination was associated with higher systolic and diastolic blood pressure (β = 2.23 mm Hg (95% confidence interval: 1.85, 2.61) and β = 1.31 (95% confidence interval: 1.00, 1.62), respectively). Our instrumental variable estimates suggest that experiences of racial discrimination within institutional settings contribute to racial inequities in elevated blood pressure and cardiovascular disease outcomes in a relatively young cohort of adults and may yield clinically relevant differences in cardiovascular health over the life course.
Regulation of synthesis of polyamines by progesterone, estradiol, and their receptors in uteri of cyclic ewes
Authors: Newton Makenzie G , Stenhouse Claire , Halloran Katherine M , Sah Nirvay , Moses Robyn M , He Wenliang , Wu Guoyao , Bazer Fuller W
Published: July 2023

Progesterone (P4), estradiol (E2), and expression of their receptors (PGR and ESR1, respectively) by cells of the uterus regulate reproductive performance of mammals through effects on secretion and transport of nutrients into the uterine lumen. This study investigated the effect of changes in P4, E2, PGR, and ESR1 on expression of enzymes for the synthesis and secretion of polyamines. Suffolk ewes (n = 13) were synchronized to estrus (Day 0) and then, on either Day 1 (early metestrus), Day 9 (early diestrus), or Day 14 (late diestrus) of the estrous cycle, maternal blood samples were collected, and ewes were euthanized before obtaining uterine samples and uterine flushings. Endometrial expression of MAT2B and SMS mRNAs increased in late diestrus (P < 0.05). Expression of ODC1 and SMOX mRNAs decreased from early metestrus to early diestrus, and expression of ASL mRNA was lower in late diestrus than in early metestrus (P < 0.05). Immunoreactive PAOX, SAT1, and SMS proteins were localized to uterine luminal, superficial glandular, and glandular epithelia, stromal cells, myometrium, and blood vessels. Concentrations of spermidine and spermine in maternal plasma decreased from early metestrus to early diestrus and decreased further in late diestrus (P < 0.05). The abundances of spermidine and spermine in uterine flushings were less in late diestrus than early metestrus (P < 0.05). These results indicate that synthesis and secretion of polyamines are affected by P4 and E2, as well as the expression of PGR and ESR1 in the endometria of cyclic ewes.