Impact of thermal behaviour on outdoor human thermal comfort in tropical climate

In recent years, the challenges of the urban environment have been identified as urban heat island phenomenon due to the impacts of thermal behaviour from the surrounding built-up environment, with a low surface albedo. Their impacts on individuals are getting worse due to improper urban building designs with albedo modification that changed thermal behaviour in cities which in turn affects the quality of thermal comfort, especially in tropical countries. Therefore, this research aims to evaluate human thermal comfort by developing a preferable range of Discomfort Index (DI) interpretation for tropical climate. Next, the study integrates the application of a Surrogate Human Sensor (SHS) with measurements of climatic variables. Following this, Heat Stress Index (HSI) and Thermal Comfort Index (TCI) are established, using the correlation of the thermal perception with SHS and climatic variables measurement for evaluating thermal comfort in outdoor spaces. In-situ field measurements were carried out to analyse the impacts of thermal behaviour and its relationship to human discomfort. Human discomfort levels were evaluated using Thom's DI and a new extended DI range of 20°C to 28.9°C for “partially comfortable”. It was proposed in association with local climate as a result of thermal adaptability. Outdoor thermal sensations for the outdoor environment can be assessed using questionnaire surveys and a SHS model that was initially developed as a sensor to receive data on the impacts of thermal behaviour. SHS significantly reflects the impacts of thermal behaviour from the surrounding ambient environment towards human skin surface and found to be useful as a simple sensor, or indicator, for pre-assessing thermal conditions and comfort. In this study, two factors, i.e. climatic and psychological factors, are taken into consideration. Within this combination, SHS acts like a sensor to predict the thermal responses of people with respect to the influence from climatic variables. Thermal perception regression models, which represent the HSI, and SHS temperature regression models were developed based on the local microclimate environment. With this correlation, TCI was established where it enhances the understanding of the relationship between human psychologies and the climatic environment using SHS. Then, the SHS can be used to identify the perception level of the people as the SHS correlated with the thermal perception and surrounding climate measurements. All the regressions established were verified through execution in the real case scenarios by comparing the observed and predicted outputs. These verifications have shown that the regressions may be suitably applied in all tropical climate locations, especially in Malaysia, to evaluate correctly outdoor thermal comfort

Dimensional Stability of Lightweight Foamed Concrete Containing Eggshell Powder and Calcium Stearate

In order to reduce eggshell (ES) waste and reduce utilization of pure cement, various researches were conducted to study effects of eggshell powder (ESP) on properties of concrete when it partially replaces ordinary Portland cement (OPC). Dimensional stability is one of the properties that related to cracking issue and soundness of concrete, and it is generally guided by movement of moisture. This study was conducted to study the sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete (LFC) that containing eggshell powder and calcium stearate (CS), where, replacement level (RL) of eggshell powder ranged from 0% to 10% at interval of 2.5%, and additional of 1% calcium stearate as cement mass applied for the mixture containing 0% and 5% eggshell powder. The result shows that eggshell powder improves sorptivity, initial surface absorption, and dimensional stability of lightweight foamed concrete and the optimal replacement level is 5%. The result also shows that calcium stearate significantly improves these properties, regardless that incorporation of eggshell powder in the mixture containing calcium stearate might slightly deteriorate these properties. Besides, based on the results, improved sorptivity and initial surface absorption result in increased magnitude of shrinkage as the specimen has lower ability to absorb water for expansion throughout the testing period

Tud-1 supported vanadium-doped titania photocatalyst

New photocatalyst of Techniche Universiteit Delft-1 (TUD-1) supported 5 mol% V doped TiO2 (5V-TiO2 /TUD-1) exhibited enhanced activity in methylene blue photodegradation. XRD results revealed the presence of both anatase and rutile phases in the V-doped TiO2 sample. After loading onto TUD-1, the crystallinity of the sample dropped significantly, implying well dispersion of both V and TiO2 on the TUD-1. DRUV-Vis results suggested alteration of Ti species in the presence of TUD-1. Besides, the band gap energy of V-doped TiO2 decreased after loading onto TUD-1. The sample 5V-TiO2 /TUD-1 possessed high surface area of 626 m2 /g. The photocatalytic performance of the sample was evaluated through the photodegradation of methylene blue under UV irradiation. It has been demonstrated that 5V-TiO2 /TUD-1 was a better photocatalyst compared to TUD-1 and unsupported V-doped TiO2 . The current findings strongly indicated that TUD-1 played an important role as support to improve the photocatalytic activity of V-doped TiO2

Systematic design of single-mode coupled-resonator optical waveguides in photonic crystals

By establishing a direct relation between the dispersion and the field profile of a coupled-resonator optical waveguide (CROW) and those of its constituent cavities, we present a systematic method for the design of a single-mode CROW and for control of its dispersion. The procedure includes the design of a single-mode cavity and control of its frequency by engineering its structure. Then, by chaining these cavities in the proper direction and at an appropriate distance, we achieve the desired dispersion for the CROW

EDITORIAL : EMPOWERING INDUSTRY AND TRANSFORMING SOCIETY TOWARDS SUSTAINABLE DEVELOPMENT

This special issue presents the selected peer-reviewed full-text papers from the 13th International UNIMAS Engineering Conference 2020 (EnCon 2020), which was successfully organised through an online platform on October 27-28, 2020 by the Faculty of Engineering of Universiti Malaysia Sarawak (UNIMAS), Malaysia, along with various prominent co-organizers, the Institution of Engineers, Malaysia (IEM), Swinburne University of Technology, Malaysia, SRM Institute of Science and Technology, India, the Institute of Electrical and Electronics Engineers (IEEE), Malaysia and Universiti Teknologi PETRONAS (UTP), Malaysia

A Comparative Assessment of Online Learning Readiness for First Year and Final Year Engineering Undergraduates

Measuring student readiness in online learning should also be of great concern to institutions, including all areas from their curricular development to the pedagogies they experience. Although there have been attempts at universities to develop online learning courses, students' readiness has yet to be investigated, particularly for engineering students who take a mix of theoretical and practical-based courses. This study evaluates the readiness of civil engineering students toward the implementation of online learning and their preferences and acceptance towards online instructional delivery and assessment methods. Ways for improvement are proposed in line with the students’ readiness to determine the best desirable practices and strategies for online pedagogy. Respondents are selected from first and final year students, to examine and compare their online learning perspectives. A survey questionnaire was used. Findings revealed that year one and year four students' readiness were relatively moderate for most of the components and relatively high for the components that involved hardware/software requirements and technology skills. Most respondents indicated a moderate acceptance level on online assessment, ranging from a mean score of 3.46 to 3.81. As online learning is gradually becoming another method for life-long and self-determined learning, findings from the study might help university educators to develop better online learning strategies, especially delivery methods and assessments, to help students cope with online learning

Monoclinic and Correlated Metal Phase in VO_2 as Evidence of the Mott Transition: Coherent Phonon Analysis

In femtosecond pump-probe measurements, the appearance of coherent phonon oscillations at 4.5 THz and 6.0 THz indicating the rutile metal phase of VO_2 does not occur simultaneously with the first-order metal-insulator transition (MIT) near 68^oC. The monoclinic and correlated metal(MCM) phase between the MIT and the structural phase transition (SPT) is generated by a photo-assisted hole excitation which is evidence of the Mott transition. The SPT between the MCM phase and the rutile metal phase occurs due to subsequent Joule heating. The MCM phase can be regarded as an intermediate non-equilibrium state.Comment: 4 pages, 2 figure

Classification of Potential Risk Factors through HIRARC Method in Assessing Indoor Environment of Museums

Museums were established in Malaysia more than hundred years ago. Since the year 2005, Malaysia has been moving away from constructing new buildings in favor of refurbishing historic and old ones. A healthy environment at the museum building has been identified as one of the important element that must been considered. Here, IAQ has become an important factor to provide a healthy environment in the museum building, but it is not sure either IAQ in the museum building provide a good air quality or not.  So, the purpose of this study was conducted to determine the potential risk factor of the museum building by using the Potential Risk Categories, as a tool to identify the suitable location to conduct the indoor environment assessment at the museum building. Based on four mains criteria in the Potential Risk Categories, it is found that, out of 24 museum buildings, there were 8 museum buildings has been identified as a medium potential risk while 16 museum buildings are low potential risk. So, the selection of location based on Potential Risk Categories is important for the next step of indoor environment assessment at museum building, so that the most critical risk museum building could be assessed and suggestion could be provided to minimize the potential risk available in the museum building

Cloning, expression and purification of squalene synthase from Candida tropicalis in Pichia pastoris

Squalene synthase (SS) is the key precursor and first committed enzyme of the sterol biosynthesis pathway. In a previous work, SS has been identified as one of the immunogenic proteins that could be a potential diagnostic candidate for the pathogenic fungus Candida tropicalis. In this study, SS from C. tropicalis was cloned and expressed as recombinant protein in Pichia pastoris to investigate its reactivity with serum antibodies. ERG9 gene that encodes for SS was amplified by PCR and cloned in-frame into pPICZB expression vector. The recombinant construct was then transformed into P. pastoris GS115 host strain. Expression of the recombinant protein was confirmed by SDS–PAGE and Western blot analysis using anti-His tag probe. Optimal protein production was achieved by cultivating the culture with 1.0% methanol for 72 h. The recombinant protein was purified to approximately 97% pure in a single step immobilized metal affinity chromatography with a yield of 70.3%. Besides, the purified protein exhibited specific reactivity with immune sera on Western blot. This is the first report on heterologous expression of antigenic SS from C. tropicalis in P. pastoris which can be exploited for large-scale production and further research. The results also suggested that the protein might be of great value as antigen candidate for serodiagnosis of Candida infection