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Dr. Sheikh Ahmad Zaki
Universiti Teknologi Malaysia

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0 Thermal Comfort
0 Wind Engineering
0 Wind Tunnel
0 urban climatology
0 Occupant Behavior

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Passive Cooling

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Journal article
Published: 13 August 2021 in Sustainability
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Comfort temperature and sleep quality involving 20 participants were determined in two cases: Case A (arbitrary, controlled air-conditioner setting) and Case B (adjustment of 3 °C higher than the setting of Case A with cool bed linen). Data of indoor thermal comfort and electricity consumption were collected every night throughout the measurement period. Questionnaires on thermal comfort and sleep quality were distributed twice a night for a duration of three nights for each case; the first night was for respondents’ adaptation and the following two nights were for measurement. The sleep quality of the respondents was objectively measured using a commercially available activity tracker. Results found that most respondents were thermally comfortable in both cases, with 39% lower energy consumption reported for Case B compared to Case A. The thermal conditions of Case B were found to be more tolerable than those of Case A. Most respondents reported to have a calm and satisfied sleep for both cases. Comfort temperature and Sleep Efficiency Index (SEI) were found to be maintained in both cases.

ACS Style

Sheikh Ahmad Zaki; Mohamad Faizal Rosli; Hom Bahadur Rijal; Farah Nurhanis Hassan Sadzli; Aya Hagishima; Fitri Yakub. Effectiveness of a Cool Bed Linen for Thermal Comfort and Sleep Quality in Air-Conditioned Bedroom under Hot-Humid Climate. Sustainability 2021, 13, 9099 .

AMA Style

Sheikh Ahmad Zaki, Mohamad Faizal Rosli, Hom Bahadur Rijal, Farah Nurhanis Hassan Sadzli, Aya Hagishima, Fitri Yakub. Effectiveness of a Cool Bed Linen for Thermal Comfort and Sleep Quality in Air-Conditioned Bedroom under Hot-Humid Climate. Sustainability. 2021; 13 (16):9099.

Chicago/Turabian Style

Sheikh Ahmad Zaki; Mohamad Faizal Rosli; Hom Bahadur Rijal; Farah Nurhanis Hassan Sadzli; Aya Hagishima; Fitri Yakub. 2021. "Effectiveness of a Cool Bed Linen for Thermal Comfort and Sleep Quality in Air-Conditioned Bedroom under Hot-Humid Climate." Sustainability 13, no. 16: 9099.

Journal article
Published: 23 April 2021 in Urban Climate
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In residential buildings, accurate forecast of time-varying electricity demands is important for the estimation and prediction of electricity consumption. Information of the end user's electricity consumption patterns is necessary as it has a significant impact on the load curve in the utility grid. Thus, this study aims to provide detailed information on the electricity use and indoor thermal environment for typical residential buildings. Field measurements were conducted in 19 selected dwellings in Kuala Lumpur, Malaysia to specifically measure the total and the air conditioner (AC) electricity usage along with the indoor thermal environment. There were significant differences in the total electricity consumption among low-, middle-, and high-income dwellings. However, for the AC electricity consumption, the different income groups do not display notable differences. This might be due to the occupant behaviour of using the air conditioner mostly during sleeping hours. The measurement results of all targeted dwellings showed that the daily averages of the total and the AC electricity consumption are 14.5 kWh/day and 3.9 kWh/day, respectively. The daily averages of the AC electricity usage in the living room and the bedroom are 2.7 kWh and 4.4 kWh, respectively. The fraction of the daily peak demand from all targeted dwellings shows that the peak at the nighttime is due to the use of the air conditioner. Moreover, the patterns of hourly indoor thermal environment showed an average of 30.1 °C (living room) and 29.3 °C (bedroom). Generally, the comfort level for the indoor temperature lies between 23 °C and 26 °C, while for relative humidity, the comfortable range is between 40% and 70%. These findings provide preliminary understanding of the detailed characteristics of residential electricity use and indoor environment in Malaysian dwellings and can be used to predict the electricity demand in the future.

ACS Style

Naja Aqilah; Sheikh Ahmad Zaki; Aya Hagishima; Hom Bahadur Rijal; Fitri Yakub. Analysis on electricity use and indoor thermal environment for typical air-conditioning residential buildings in Malaysia. Urban Climate 2021, 37, 100830 .

AMA Style

Naja Aqilah, Sheikh Ahmad Zaki, Aya Hagishima, Hom Bahadur Rijal, Fitri Yakub. Analysis on electricity use and indoor thermal environment for typical air-conditioning residential buildings in Malaysia. Urban Climate. 2021; 37 ():100830.

Chicago/Turabian Style

Naja Aqilah; Sheikh Ahmad Zaki; Aya Hagishima; Hom Bahadur Rijal; Fitri Yakub. 2021. "Analysis on electricity use and indoor thermal environment for typical air-conditioning residential buildings in Malaysia." Urban Climate 37, no. : 100830.

Journal article
Published: 06 April 2021 in Polymers
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Utilizing agro-waste material such as rice husk (RH) and coco peat (CP) reinforced with thermoplastic resin to produce low-cost green composites is a fascinating discovery. In this study, the effectiveness of these blended biocomposites was evaluated for their physical, mechanical, and thermal properties. Initially, the samples were fabricated by using a combination of melt blend internal mixer and injection molding techniques. Increasing in RH content increased the coupons density. However, it reduced the water vapor kinetics sorption of the biocomposite. Moisture absorption studies disclosed that water uptake was significantly increased with the increase of coco peat (CP) filler. It showed that the mechanical properties, including tensile modulus, flexural modulus, and impact strength of the 15% RH—5% CP reinforced acrylonitrile-butadiene-styrene (ABS), gave the highest value. Results also revealed that all RH/CP filled composites exhibited a brittle fracture manner. Observation on the tensile morphology surfaces by using a scanning electron microscope (SEM) affirmed the above finding to be satisfactory. Therefore, it can be concluded that blend-agriculture waste reinforced ABS biocomposite can be exploited as a biodegradable material for short life engineering application where good mechanical and thermal properties are paramount.

ACS Style

Nurul Norhasnan; Mohamad Hassan; Ariff Nor; S. Zaki; Rozzeta Dolah; Khairur Jamaludin; Sa’Ardin Aziz. Physicomechanical Properties of Rice Husk/Coco Peat Reinforced Acrylonitrile Butadiene Styrene Blend Composites. Polymers 2021, 13, 1171 .

AMA Style

Nurul Norhasnan, Mohamad Hassan, Ariff Nor, S. Zaki, Rozzeta Dolah, Khairur Jamaludin, Sa’Ardin Aziz. Physicomechanical Properties of Rice Husk/Coco Peat Reinforced Acrylonitrile Butadiene Styrene Blend Composites. Polymers. 2021; 13 (7):1171.

Chicago/Turabian Style

Nurul Norhasnan; Mohamad Hassan; Ariff Nor; S. Zaki; Rozzeta Dolah; Khairur Jamaludin; Sa’Ardin Aziz. 2021. "Physicomechanical Properties of Rice Husk/Coco Peat Reinforced Acrylonitrile Butadiene Styrene Blend Composites." Polymers 13, no. 7: 1171.

Journal article
Published: 01 March 2021 in Journal of Wind Engineering and Industrial Aerodynamics
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A rectangular cylinder in a fluid flow is known to show complicated cross-flow vibration behavior due to the interaction between the Kármán vortex-induced vibration and galloping. Wind tunnel experiments were carried out to investigate the cross-flow vibration behavior of several rectangular cylinders for which different stream-wise lengths, B and a fixed cross-flow height, D were used to define the side ratio, B/D of 1.0, 1.2, 1.4, and 1.6. For the isolated cylinder, stronger interaction between KVIV and galloping was demonstrated as the B/D was increased. The placement of a downstream square plate at a gap, S from the cylinder had a significant effect on the peak of VIV, AVIV of the cylinder. With the downstream square plate at S/D ​= ​1.17, the AVIV was enhanced about five times than that of the isolated cylinder (B/D ​= ​1.0). In contrast, the AVIV was suppressed by about 50% for two cylinders, B/D ​= ​1.2 and 1.6, with S/D ​= ​1.15 and 2.12, respectively. However, galloping was significantly enhanced for two cylinders, B/D ​= ​1.2 and 1.4 with S/D ​= ​1.15. These findings are useful to develop a vibration control technique crucial to avoid hazardous vibrations or to induce vibrations for beneficial purposes.

ACS Style

Azhar Mohamed; Sheikh Ahmad Zaki; Masataka Shirakashi; Mohamed Sukri Mat Ali; Muhammad Zulfahmi Samsudin. Experimental investigation on vortex-induced vibration and galloping of rectangular cylinders of varying side ratios with a downstream square plate. Journal of Wind Engineering and Industrial Aerodynamics 2021, 211, 104563 .

AMA Style

Azhar Mohamed, Sheikh Ahmad Zaki, Masataka Shirakashi, Mohamed Sukri Mat Ali, Muhammad Zulfahmi Samsudin. Experimental investigation on vortex-induced vibration and galloping of rectangular cylinders of varying side ratios with a downstream square plate. Journal of Wind Engineering and Industrial Aerodynamics. 2021; 211 ():104563.

Chicago/Turabian Style

Azhar Mohamed; Sheikh Ahmad Zaki; Masataka Shirakashi; Mohamed Sukri Mat Ali; Muhammad Zulfahmi Samsudin. 2021. "Experimental investigation on vortex-induced vibration and galloping of rectangular cylinders of varying side ratios with a downstream square plate." Journal of Wind Engineering and Industrial Aerodynamics 211, no. : 104563.

Journal article
Published: 05 February 2021 in Ocean Engineering
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We investigated the displacement and lift time series of a circular cylinder - strip plate cruciform system for energy harvesting in the Reynolds number range 1.1×103≤Re≤14.6×103, numerically using the open source C++ library: OpenFOAM. The Karman vortex-induced vibration (KVIV) regime was identified between reduced velocity, U*, 2.3 and 13.6, while the streamwise vortex-induced vibration (SVIV) regime was identified between 18.2≤U*≤29.5. We analysed the cylinder displacement and lift time series using the Hilbert-Huang transform (HHT). Within this range of U*, Karman vortex shedding contributes nearly as much as streamwise vortex shedding to the root-mean-square amplitude of total lift, while between 25.0≤U*≤29.5, the Karman component contribution is on average twice that of the streamwise component. These findings hint at the possibility to improve the power output of the harvester by a factor of two between 18.2≤U*≤22.7 and by a factor of three between 25.0≤U*≤29.5, if we can unite the contribution to the root-mean-square amplitude of the total lift under a single vibration-driving mechanism: the shedding of streamwise vortex.

ACS Style

Ahmad Adzlan; Mohamed Sukri Mat Ali; Sheikh Ahmad Zaki. Temporal evolution of lift in a pure cruciform system for energy harvesting. Ocean Engineering 2021, 223, 108648 .

AMA Style

Ahmad Adzlan, Mohamed Sukri Mat Ali, Sheikh Ahmad Zaki. Temporal evolution of lift in a pure cruciform system for energy harvesting. Ocean Engineering. 2021; 223 ():108648.

Chicago/Turabian Style

Ahmad Adzlan; Mohamed Sukri Mat Ali; Sheikh Ahmad Zaki. 2021. "Temporal evolution of lift in a pure cruciform system for energy harvesting." Ocean Engineering 223, no. : 108648.

Journal article
Published: 15 January 2021 in Sustainability
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Electricity-saving strategies are an essential solution to overcoming increasing global CO2 emission and electricity consumption problems; therefore, the determinant factors of electricity consumption in households need to be assessed. Most previous studies were conducted in developed countries of subtropical regions that had different household characteristic factors from those in developing countries of tropical regions. A field survey was conducted on electricity consumption for Malaysian households to investigate the factors affecting electricity consumption that focused on technology perspective (building and appliance characteristics) and socio-economic perspective (socio-demographics and occupant behaviour). To analyse the determinant factors of electricity consumption, direct and indirect questionnaire surveys were conducted from November 2017 to January 2018 among 214 university students. Direct questionnaire surveys were performed in order to obtain general information that is easily answered by respondents. On the other hand, some questions such as electricity consumption and detailed information of appliances must be confirmed by the respondents’ parents or other household members through an indirect questionnaire survey. The results from multiple linear regression analyses of the survey responses showed that appliance characteristic factors were the main variables influencing electricity consumption and house characteristics were the least significant. Specifically, air conditioners, fluorescent lamps, and flat-screen TVs emerged as appliances with the most significant effect on electricity consumption. Occupant behaviour factors had a more significant influence than socio-demographic factors. The findings in this study can be used by policymakers to develop electricity-saving strategies in Malaysia.

ACS Style

Boni Sena; Sheikh Zaki; Hom Rijal; Jorge Ardila-Rey; Nelidya Yusoff; Fitri Yakub; Mohammad Ridwan; Firdaus Muhammad-Sukki. Determinant Factors of Electricity Consumption for a Malaysian Household Based on a Field Survey. Sustainability 2021, 13, 818 .

AMA Style

Boni Sena, Sheikh Zaki, Hom Rijal, Jorge Ardila-Rey, Nelidya Yusoff, Fitri Yakub, Mohammad Ridwan, Firdaus Muhammad-Sukki. Determinant Factors of Electricity Consumption for a Malaysian Household Based on a Field Survey. Sustainability. 2021; 13 (2):818.

Chicago/Turabian Style

Boni Sena; Sheikh Zaki; Hom Rijal; Jorge Ardila-Rey; Nelidya Yusoff; Fitri Yakub; Mohammad Ridwan; Firdaus Muhammad-Sukki. 2021. "Determinant Factors of Electricity Consumption for a Malaysian Household Based on a Field Survey." Sustainability 13, no. 2: 818.

Journal article
Published: 09 January 2021 in Sustainability
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Understanding the characteristics of natural, wind-induced ventilation of buildings is essential for accurate predictions of ventilation flow rates; however, indoor ventilation is significantly influenced by surrounding buildings. Therefore, a series of wind-tunnel experiments were performed to clarify the relationship between outdoor and indoor air flows around and within a target cube model with several openings. Two surrounding building arrangements, namely square (SQ) and staggered (ST), were placed under the condition of a building coverage ratio of 25%. The results indicated that the wind speed near the windward openings on the streamwise faces showed 0.3 to the reference wind speed, whereas those on the lateral faces were less than 0.1; these numbers indicate that the opening positions significantly affect the mean indoor wind speed. Furthermore, the temporal fluctuations of velocities near the opening demonstrated that the introduction of the flow is significantly affected by turbulent flow due to the surrounding buildings. In addition, correlation between the outdoor and indoor air flows was observed. The highest correlations were obtained for both opening conditions with a certain temporal delay. This result indicates that indoor air flows become turbulent because of the turbulent flows generated by the surrounding outdoor buildings; however, slight temporal delays could occur between indoor and outdoor air flows. Although the present study focuses on the fundamental turbulent characteristics of indoor and outdoor air flows, such findings are essential for accurately predicting the ventilation flow rate due to turbulent air flows for sheltered buildings.

ACS Style

Ahmad Mohammad; Naoki Ikegaya; Ryo Hikizu; Sheikh Zaki. Turbulence Effect of Urban-Canopy Flow on Indoor Velocity Fields under Sheltered and Cross-Ventilation Conditions. Sustainability 2021, 13, 586 .

AMA Style

Ahmad Mohammad, Naoki Ikegaya, Ryo Hikizu, Sheikh Zaki. Turbulence Effect of Urban-Canopy Flow on Indoor Velocity Fields under Sheltered and Cross-Ventilation Conditions. Sustainability. 2021; 13 (2):586.

Chicago/Turabian Style

Ahmad Mohammad; Naoki Ikegaya; Ryo Hikizu; Sheikh Zaki. 2021. "Turbulence Effect of Urban-Canopy Flow on Indoor Velocity Fields under Sheltered and Cross-Ventilation Conditions." Sustainability 13, no. 2: 586.

Original paper
Published: 08 January 2021 in International Journal of Biometeorology
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Difficulties in controlling the effects of outdoor thermal environment on the human body are attracting considerable research attention. This study investigated the outdoor thermal comfort of urban pedestrians by assessing their perceptions of the tropical, micrometeorological, and physical conditions via a questionnaire survey. Evaluation of the outdoor thermal comfort involved pedestrians performing various physical activities (sitting, walking, and standing) in outdoor and semi-outdoor spaces where the data collection of air temperature, globe temperature, relative humidity, wind speed, solar radiation, metabolic activity, and clothing insulation data was done simultaneously. A total of 1011 participants were interviewed, and the micrometeorological data were recorded under outdoor and semi-outdoor conditions at two Malaysian university campuses. The neutral temperatures obtained which were 28.1 °C and 30.8 °C were within the biothermal acceptable ranges of 24–34 °C and 26–33 °C of the PET thermal sensation ranges for the outdoor and semi-outdoor conditions, respectively. Additionally, the participants’ thermal sensation and preference votes were highly correlated with the PET and strongly related to air and mean radiant temperatures. The findings demonstrated the influence of individuals’ thermal adaptation on the outdoor thermal comfort levels. This knowledge could be useful in the planning and designing of outdoor environments in hot and humid regions to create better thermal environments.

ACS Style

Nurnida Elmira Othman; Sheikh Ahmad Zaki; Hom Bahadur Rijal; Nurul Huda Ahmad; Azli Abd Razak. Field study of pedestrians’ comfort temperatures under outdoor and semi-outdoor conditions in Malaysian university campuses. International Journal of Biometeorology 2021, 65, 453 -477.

AMA Style

Nurnida Elmira Othman, Sheikh Ahmad Zaki, Hom Bahadur Rijal, Nurul Huda Ahmad, Azli Abd Razak. Field study of pedestrians’ comfort temperatures under outdoor and semi-outdoor conditions in Malaysian university campuses. International Journal of Biometeorology. 2021; 65 (4):453-477.

Chicago/Turabian Style

Nurnida Elmira Othman; Sheikh Ahmad Zaki; Hom Bahadur Rijal; Nurul Huda Ahmad; Azli Abd Razak. 2021. "Field study of pedestrians’ comfort temperatures under outdoor and semi-outdoor conditions in Malaysian university campuses." International Journal of Biometeorology 65, no. 4: 453-477.

Articles
Published: 30 September 2020 in Science and Technology for the Built Environment
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Many studies have been conducted to assess the effects of indoor air quality (IAQ) on human health. However, there is still a lack of studies available about the adverse health effects on children’s respiratory health at Child Care Centres (CCC). The aim of this paper was to investigate the risk factors for respiratory symptoms and identify the root cause of IAQ problems at CCCs in Malaysia. The Modified American Thoracic Society and the Division of Lung Diseases (ATS-DLD-82) questionnaire was used to gather information from parents regarding their children’s respiratory symptoms. The IAQ parameters measured were for air temperature, humidity, carbon dioxide, carbon monoxide, respirable particles (PM2.5), viable bacteria and fungi count while the information on CCC characteristics and potential surrounding air pollutants were collected via a combination of area monitoring, inspection and interviews. Factors found to be significantly associated with persistent cough and/or cold were age, type of ventilation, location of CCC, floor area per child (<3.5m2) and temperature. Children attending CCCs supplied by ACMV had the highest risk for prevalence of persistent productive cough [5.56 (CI: 2.20; 14.00)]. This study provided the baseline data on IAQ and possible factors that influenced indoor air contaminants, which could aid policy makers in formulating guidelines on IAQ for CCC in Malaysia.

ACS Style

Abdul Malik; Rafiza Shaharudin; Azli Abd Razak; Muhad Rozi Mat Nawi; Mohd Faizal Mohamad; Sheikh Ahmad Zaki Shaikh Salim. Prevalence and risk factors for respiratory symptoms among children at child care centers in Malaysia. Science and Technology for the Built Environment 2020, 27, 129 -138.

AMA Style

Abdul Malik, Rafiza Shaharudin, Azli Abd Razak, Muhad Rozi Mat Nawi, Mohd Faizal Mohamad, Sheikh Ahmad Zaki Shaikh Salim. Prevalence and risk factors for respiratory symptoms among children at child care centers in Malaysia. Science and Technology for the Built Environment. 2020; 27 (2):129-138.

Chicago/Turabian Style

Abdul Malik; Rafiza Shaharudin; Azli Abd Razak; Muhad Rozi Mat Nawi; Mohd Faizal Mohamad; Sheikh Ahmad Zaki Shaikh Salim. 2020. "Prevalence and risk factors for respiratory symptoms among children at child care centers in Malaysia." Science and Technology for the Built Environment 27, no. 2: 129-138.

Journal article
Published: 06 September 2020 in Sustainability
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As a Malay Agricultural Settlement established in 1900, Kampung Baru which is located in Kuala Lumpur, has become a subject of prolonged national interests in terms of economic, social, environment, and political issues along with the pressure of modern and future development. This study investigated the urban morphological impact of Kampung Baru on the intensity of urban heat island (UHI) by developing a smart geodatabase for urban climatic mapping. The database provided baseline data which was crucial to unveil the spatiotemporal characteristics of UHI in Kampung Baru. Determination of the urban heat island intensity (UHII) in Kampung Baru was carried out through two approaches, mobile and fixed measurements. In a period of six days, the mobile measurement was conducted within the target area at night using a motorcycle equipped with the temperature and relative humidity data logger while the fixed measurement was conducted using the similar equipment installed at a school building in the area. Building height data were also collected while building footprints were digitized using a topographical map and the satellite image was used as the base map. To estimate the UHII, the reference data for rural temperature was obtained from the Malaysian Meteorological Department (MMD). All of the data were analyzed using ArcGIS to portray the temperature pattern in the study area. The analysis revealed the presence of UHI effect in Kampung Baru at the average building height of six to ten metres. The results of the fixed measurement showed an island-like local maximum in the study area with the average and maximum UHII values of 4.4 °C and 6.0 °C, respectively. The results from the mobile measurement also showed that the highest temperature was recorded in Kampung Baru rather than in the surrounding areas of different land-use types throughout the observation days. The spatial temperature distribution in the study area also showed that the most affected part was the south-west of Kampung Baru which is surrounded by tall buildings. The findings of this study could be utilized in the planning of new development in the city of Kuala Lumpur.

ACS Style

Sheikh Zaki; Nor Azid; Mohd Shahidan; Mohamad Hassan; Mohd Md Daud; Nor Abu Bakar; Sheikh Ahmad Zaki Shaikh Salim; Fitri Yakub. Analysis of Urban Morphological Effect on the Microclimate of the Urban Residential Area of Kampung Baru in Kuala Lumpur Using a Geospatial Approach. Sustainability 2020, 12, 7301 .

AMA Style

Sheikh Zaki, Nor Azid, Mohd Shahidan, Mohamad Hassan, Mohd Md Daud, Nor Abu Bakar, Sheikh Ahmad Zaki Shaikh Salim, Fitri Yakub. Analysis of Urban Morphological Effect on the Microclimate of the Urban Residential Area of Kampung Baru in Kuala Lumpur Using a Geospatial Approach. Sustainability. 2020; 12 (18):7301.

Chicago/Turabian Style

Sheikh Zaki; Nor Azid; Mohd Shahidan; Mohamad Hassan; Mohd Md Daud; Nor Abu Bakar; Sheikh Ahmad Zaki Shaikh Salim; Fitri Yakub. 2020. "Analysis of Urban Morphological Effect on the Microclimate of the Urban Residential Area of Kampung Baru in Kuala Lumpur Using a Geospatial Approach." Sustainability 12, no. 18: 7301.

Journal article
Published: 16 July 2020 in Sustainability
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This study investigated the variation of outdoor air temperature in the shaded area covered by buildings in an urban university campus in Malaysia. In-situ field measurements were conducted to measure the distribution of outdoor air temperature at eight different locations for seven days. Meanwhile, the building-induced shadows were generated using the AutoCAD Revit software to investigate the air temperature change. The study used four urban morphological parameters namely building to greenery ratio, sky view factor (SVF), and height-to-street width (H/W) ratio. The relationship between building-induced shadow and outdoor air temperature (Tout) obtained from the in-situ measurement was investigated. The results showed that the building-induced shadows could lower air temperature. It can be noted that a high ratio of building to greenery resulted in a higher air temperature. In contrast, the area with a low SVF value due to the combination of prolonged shading by buildings and trees had a lower air temperature. Thus, the area with a high building ratio, low greenery ratio, higher SVF value, and low H/W ratio potentially has a higher outdoor air temperature. Conclusively, combination of building shading created by appropriate ratio of building morphology and sufficient greenery able to improve the microclimate of a campus area.

ACS Style

Sheikh Zaki; Siti Syahidah; Mohd Shahidan; Mardiana Ahmad; Fitri Yakub; Mohamad Hassan; Mohd Md Daud. Assessment of Outdoor Air Temperature with Different Shaded Area within an Urban University Campus in Hot-Humid Climate. Sustainability 2020, 12, 5741 .

AMA Style

Sheikh Zaki, Siti Syahidah, Mohd Shahidan, Mardiana Ahmad, Fitri Yakub, Mohamad Hassan, Mohd Md Daud. Assessment of Outdoor Air Temperature with Different Shaded Area within an Urban University Campus in Hot-Humid Climate. Sustainability. 2020; 12 (14):5741.

Chicago/Turabian Style

Sheikh Zaki; Siti Syahidah; Mohd Shahidan; Mardiana Ahmad; Fitri Yakub; Mohamad Hassan; Mohd Md Daud. 2020. "Assessment of Outdoor Air Temperature with Different Shaded Area within an Urban University Campus in Hot-Humid Climate." Sustainability 12, no. 14: 5741.

Journal article
Published: 13 May 2020 in Energy and Buildings
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Although various cooling approaches have been proposed to overcome the thermal discomfort in residential buildings, tropical developing countries still lack affordable and effective retrofitting methods. The objective of this study was to evaluate the effectiveness of an affordable retrofitting method with high-density polyethylene (HDPE) nets as roof covers for shading over the roof, supported by full day free-running ventilation, and heat insulation above the ceiling of residential buildings in hot–humid climate regions to overcome the thermal discomfort. Field measurements were carried out in a corner terrace house in Malaysia, from September to December 2018. The roof cover with HDPE nets maintained a consistent surface temperature at the roof tiles and reduced the convective heat flux by approximately 70–80% in the attic and 88% in the room. Further, it improved the compliance (acceptability: 80%) of the whole-day mean operative temperature in the room (hot–humid climate) by 10%. The roof cover can effectively provide thermal comfort in residential buildings in Malaysia, which has a hot–humid climate. Alongside active cooling with the ceiling fan, required comfortable indoor temperature can be reached under the hot–humid climate, particularly during the night-time. Furthermore, the zero-energy-consuming, low-cost low-technology roof cover method is very suitable for low-cost houses with roof tile in hot–humid climate regions.

ACS Style

Ng Wai Tuck; Sheikh Ahmad Zaki; Aya Hagishima; Hom Bahadur Rijal; Fitri Yakub. Affordable retrofitting methods to achieve thermal comfort for a terrace house in Malaysia with a hot–humid climate. Energy and Buildings 2020, 223, 110072 .

AMA Style

Ng Wai Tuck, Sheikh Ahmad Zaki, Aya Hagishima, Hom Bahadur Rijal, Fitri Yakub. Affordable retrofitting methods to achieve thermal comfort for a terrace house in Malaysia with a hot–humid climate. Energy and Buildings. 2020; 223 ():110072.

Chicago/Turabian Style

Ng Wai Tuck; Sheikh Ahmad Zaki; Aya Hagishima; Hom Bahadur Rijal; Fitri Yakub. 2020. "Affordable retrofitting methods to achieve thermal comfort for a terrace house in Malaysia with a hot–humid climate." Energy and Buildings 223, no. : 110072.

Journal article
Published: 08 April 2020 in Sustainability
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This study investigated the effects of urban morphology on microclimate parameters in an urban university campus in Malaysia. Outdoor air temperatures (Tout) were recorded at eight different locations inside the campus for seven days. The study used three urban morphological parameters such as green cover ratio, height-to-width (H/W) ratio, and sky view factor (SVF). The relationship between urban morphological parameters and Tout obtained from in situ measurements was investigated. The results showed that, at a dense green cover ratio of 22% in a 7833 m2 area where the H/W ratio was 0.2, Tout was reduced by about 1% due to a long building shadow cover (12 h) and a high range of SVF (from 0.61 to 0.68). The use of geographic information system (GIS) to generate the spatial data of Universiti Teknologi Malaysia Kuala Lumpur Campus (UTMKL), morphological features and in situ Tout distributions provided useful information of Tout variations, and proved the applicability of GIS as a useful tool in smart city urban planning.

ACS Style

Sheikh Ahmad Zaki; Nurnida Elmira Othman; Siti Wan Syahidah; Fitri Yakub; Firdaus Muhammad-Sukki; Jorge Alfredo Ardila-Rey; Mohd Fairuz Shahidan; Ahmad Shakir Mohd Saudi. Effects of Urban Morphology on Microclimate Parameters in an Urban University Campus. Sustainability 2020, 12, 2962 .

AMA Style

Sheikh Ahmad Zaki, Nurnida Elmira Othman, Siti Wan Syahidah, Fitri Yakub, Firdaus Muhammad-Sukki, Jorge Alfredo Ardila-Rey, Mohd Fairuz Shahidan, Ahmad Shakir Mohd Saudi. Effects of Urban Morphology on Microclimate Parameters in an Urban University Campus. Sustainability. 2020; 12 (7):2962.

Chicago/Turabian Style

Sheikh Ahmad Zaki; Nurnida Elmira Othman; Siti Wan Syahidah; Fitri Yakub; Firdaus Muhammad-Sukki; Jorge Alfredo Ardila-Rey; Mohd Fairuz Shahidan; Ahmad Shakir Mohd Saudi. 2020. "Effects of Urban Morphology on Microclimate Parameters in an Urban University Campus." Sustainability 12, no. 7: 2962.

Journal article
Published: 02 April 2020 in Urban Climate
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An increasingly recurring recent phenomenon in tropical urban areas is the occurrence of strong winds associated with rainfall. This study investigated the characteristics of strong winds during similar rainfall events. Wind speeds and directions were measured at a sampling frequency of 10 Hz with a high-frequency three-dimensional sonic anemometer from September 2015 until January 2016 during the northeast monsoon season in Kuala Lumpur, Malaysia. Rainfall events were categorised as non-rainfall, during rainfall, before rainfall, and after rainfall. Rainfall amounts were classified as non-rainfall, heavy rainfall, and heavy shower. The results indicated that strong winds (>6.0 m s−1) with slight turbulence (0.3 turbulence intensity) typically occurred 10 min before rainfall during the day from 15:00 to 17:00 LT. Wind speeds began to decline within the first 5 min of rainfall until after the rain had stopped with a range of 2.0–5.0 m s−1. Significantly, heavy rainfall occurred with wind speeds of 8.0–9.5 m s−1 at almost double the likelihood compared to non-rainfall conditions. These findings provide useful information for the design and construction of buildings with good airflow and strong structures in urban areas.

ACS Style

Husna Aini Swarno; Sheikh Ahmad Zaki; Aya Hagishima; Yusri Yusup. Characteristics of wind speed during rainfall event in the tropical urban city. Urban Climate 2020, 32, 100620 .

AMA Style

Husna Aini Swarno, Sheikh Ahmad Zaki, Aya Hagishima, Yusri Yusup. Characteristics of wind speed during rainfall event in the tropical urban city. Urban Climate. 2020; 32 ():100620.

Chicago/Turabian Style

Husna Aini Swarno; Sheikh Ahmad Zaki; Aya Hagishima; Yusri Yusup. 2020. "Characteristics of wind speed during rainfall event in the tropical urban city." Urban Climate 32, no. : 100620.

Journal article
Published: 25 March 2020 in Journal of Advanced Research in Fluid Mechanics and Thermal Sciences
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ACS Style

Azhar Mohamed; S. M Sheikh Ahmad Zaki; Masataka Shirakashi; Sheikh Ahmad Zaki Shaikh Salim; Muhammad Zulfahmi Samsudin; Ahmad Faiz Mohammad. Experimental Investigation of the Effect of a Downstream Square Plate on Vortex-induced Vibration and Galloping of a Square Cylinder. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 2020, 68, 98 -113.

AMA Style

Azhar Mohamed, S. M Sheikh Ahmad Zaki, Masataka Shirakashi, Sheikh Ahmad Zaki Shaikh Salim, Muhammad Zulfahmi Samsudin, Ahmad Faiz Mohammad. Experimental Investigation of the Effect of a Downstream Square Plate on Vortex-induced Vibration and Galloping of a Square Cylinder. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences. 2020; 68 (1):98-113.

Chicago/Turabian Style

Azhar Mohamed; S. M Sheikh Ahmad Zaki; Masataka Shirakashi; Sheikh Ahmad Zaki Shaikh Salim; Muhammad Zulfahmi Samsudin; Ahmad Faiz Mohammad. 2020. "Experimental Investigation of the Effect of a Downstream Square Plate on Vortex-induced Vibration and Galloping of a Square Cylinder." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 68, no. 1: 98-113.

Research article
Published: 17 March 2020 in Journal of Vibration and Control
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This study investigates the control performance of a structural building system during a seismic scenario using an adaptive nonsingular terminal sliding mode control. To realize the structural integrity of a building, it is necessary to equip the building with a structural control device. This research is focused on a hybrid control device that has excellent characteristics of passive and active control devices and implemented in a three degree-of-freedom system. The system, actuator, and controllers are designed by using the mathematical model developed in MATLAB/Simulink. The input excitation to the structure is taken from the El Centro earthquake that occurred in the 1940s with a magnitude of 6.9 Mw and the Southern Sumatra earthquake that occurred in 2007 with a magnitude of 8.4 Mw. Adaptive nonsingular terminal sliding mode control is the new proposed control strategy to be applied in structural control field is investigated in terms of controller performance in suppressing the vibrations, and then, compared with sliding mode control and fuzzy logic controller strategies. Sliding mode control is chosen to be compared with adaptive nonsingular terminal sliding mode control because of its advantages of robust performance, whereas fuzzy logic controller is chosen because of its intelligent control base. The effectiveness of the proposed controllers is evaluated based on the displacement response, performance indices, and the probability of building damage. The results have shown that the new proposed controller, an adaptive nonsingular terminal sliding mode control, reduced vibrations better and has superior performance compared with fuzzy logic controller and sliding mode control.

ACS Style

Normaisharah Mamat; Fitri Yakub; Sheikh Ahmad Zaki Shaikh Salim; Mohamed Sukri Mat Ali. Seismic vibration suppression of a building with an adaptive nonsingular terminal sliding mode control. Journal of Vibration and Control 2020, 26, 2136 -2147.

AMA Style

Normaisharah Mamat, Fitri Yakub, Sheikh Ahmad Zaki Shaikh Salim, Mohamed Sukri Mat Ali. Seismic vibration suppression of a building with an adaptive nonsingular terminal sliding mode control. Journal of Vibration and Control. 2020; 26 (23-24):2136-2147.

Chicago/Turabian Style

Normaisharah Mamat; Fitri Yakub; Sheikh Ahmad Zaki Shaikh Salim; Mohamed Sukri Mat Ali. 2020. "Seismic vibration suppression of a building with an adaptive nonsingular terminal sliding mode control." Journal of Vibration and Control 26, no. 23-24: 2136-2147.

Journal article
Published: 16 March 2020 in Sustainability
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Solar energy is currently an underutilized renewable energy source that could fulfill low-temperature industrial heat demands with significant potential in high solar irradiance counties such as Malaysia. This study proposes a new systematic method for optimization of solar heat integration for different process options to minimize the levelized cost of heat by combining different methods from the literature. A case study from the literature is presented to demonstrate the proposed method combined with meteorological data in Malaysia. The method estimates capital cost and levelized cost of solar heating considering important physical constraints (e.g., available space) and recovery of waste heat. The method determines and optimizes important physical dimensions, including collector area, storage size, and control design. As the result of the case study, the solar thermal integration with Clean-In-Place streams (hot water) gives the lowest levelized cost of heat with RM 0.63/kWh (0.13 EUR/kWh) due to its lowest process temperature requirement. The sensitivity analysis indicates that collector price and collector efficiency are the critical parameters of solar thermal integration.

ACS Style

Calvin Kong Leng Sing; Jeng Shiun Lim; Timothy Gordon Walmsley; Peng Yen Liew; Masafumi Goto; Sheikh Ahmad Zaki Bin Shaikh Salim. Time-Dependent Integration of Solar Thermal Technology in Industrial Processes. Sustainability 2020, 12, 2322 .

AMA Style

Calvin Kong Leng Sing, Jeng Shiun Lim, Timothy Gordon Walmsley, Peng Yen Liew, Masafumi Goto, Sheikh Ahmad Zaki Bin Shaikh Salim. Time-Dependent Integration of Solar Thermal Technology in Industrial Processes. Sustainability. 2020; 12 (6):2322.

Chicago/Turabian Style

Calvin Kong Leng Sing; Jeng Shiun Lim; Timothy Gordon Walmsley; Peng Yen Liew; Masafumi Goto; Sheikh Ahmad Zaki Bin Shaikh Salim. 2020. "Time-Dependent Integration of Solar Thermal Technology in Industrial Processes." Sustainability 12, no. 6: 2322.

Review article
Published: 16 March 2020 in Ocean Engineering
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The in-pipe inspection robotic system is crucial in examining the inside of a pipe without compromising its structural safety. The in-pipe inspection robotic system is a promising alternative to conventional methods of x-ray inspection and visual inspection. Despite the ongoing investigation, the effectiveness of the in-pipe inspection robotic system, particularly regarding the mathematical modeling of the system design, still needs to be improved. The in-pipe inspection robot which is normally equipped with a camera or non-destructive testing (NDT) equipment moves inside the pipeline to conduct a pipe integrity assessment. The main problem during an inspection is the restricted maneuverability of the robot due to geometric changes in the pipe. This can be overcome by designing a proper mathematical model to develop an effective inspection robotic system. Therefore, this paper provides a systematic review of different modeling types of the in-pipe inspection robotic systems, including the assessment of the kinematic and dynamic mathematical models for the system. This review paper covers in-pipe inspection robotic systems with several driving mechanisms such as fluid-driven, wheeled mobile drive (WMD), screw or helical drive, legged and biomimetic drives.

ACS Style

Mohd Zamzuri Ab Rashid; Mohd Fitri Mohd Yakub; Sheikh Ahmad Zaki Bin Shaikh Salim; Normaisharah Mamat; Sharifah Munawwarah Syed Mohd Putra; Shairatul Akma Roslan. Modeling of the in-pipe inspection robot: A comprehensive review. Ocean Engineering 2020, 203, 107206 .

AMA Style

Mohd Zamzuri Ab Rashid, Mohd Fitri Mohd Yakub, Sheikh Ahmad Zaki Bin Shaikh Salim, Normaisharah Mamat, Sharifah Munawwarah Syed Mohd Putra, Shairatul Akma Roslan. Modeling of the in-pipe inspection robot: A comprehensive review. Ocean Engineering. 2020; 203 ():107206.

Chicago/Turabian Style

Mohd Zamzuri Ab Rashid; Mohd Fitri Mohd Yakub; Sheikh Ahmad Zaki Bin Shaikh Salim; Normaisharah Mamat; Sharifah Munawwarah Syed Mohd Putra; Shairatul Akma Roslan. 2020. "Modeling of the in-pipe inspection robot: A comprehensive review." Ocean Engineering 203, no. : 107206.

Articles
Published: 10 March 2020 in Science and Technology for the Built Environment
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The present study used large eddy simulations (LES) to examine the pedestrian wind velocity distribution for several cases of terraced houses with extensions. Two simulation cases of idealised terraced houses were performed with extension elements in square (E-SQ) and staggered (E-ST) arrangements. These extension elements were treated as secondary roughness. A simulation of the terraced houses without extension (NE) was also performed to provide a baseline comparison. The mean velocity distribution from LES showed that the secondary roughness strictly limited the flow penetration in both cases, which reduced the turbulent kinetic energy (TKE) inside the canyon. In comparison, E-ST had a stronger effect on TKE than E-SQ with a maximum difference of 19%. Downwind extension elements severely reduced the wind speed at the street and neighbours’ houses by about 40% to 50%. However, upwind extension elements increased the wind speed at neighbours’ houses about threefold compared to NE. The weak pedestrian wind speed at upwind houses was improved about twelve times with E-SQ and eight times with E-ST when neighbours extended their houses. This indicates that the secondary roughness significantly influences the wind distribution around buildings. Selecting the extension area is important for providing effective outdoor flow conditions.

ACS Style

Sheikh Ahmad Zaki Shaikh Salim; Mohamad Nor Hafidz Arif Razali; Naoki Ikegaya; Ahmad Faiz Mohammad; Mohamed Sukri Mat Ali. Numerical simulation of the effects of secondary roughness in the form of extension to arrays of terraced houses on pedestrian wind. Science and Technology for the Built Environment 2020, 26, 928 -940.

AMA Style

Sheikh Ahmad Zaki Shaikh Salim, Mohamad Nor Hafidz Arif Razali, Naoki Ikegaya, Ahmad Faiz Mohammad, Mohamed Sukri Mat Ali. Numerical simulation of the effects of secondary roughness in the form of extension to arrays of terraced houses on pedestrian wind. Science and Technology for the Built Environment. 2020; 26 (7):928-940.

Chicago/Turabian Style

Sheikh Ahmad Zaki Shaikh Salim; Mohamad Nor Hafidz Arif Razali; Naoki Ikegaya; Ahmad Faiz Mohammad; Mohamed Sukri Mat Ali. 2020. "Numerical simulation of the effects of secondary roughness in the form of extension to arrays of terraced houses on pedestrian wind." Science and Technology for the Built Environment 26, no. 7: 928-940.

Journal article
Published: 02 February 2020 in Sustainability
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Emerging tropical cities are experiencing rapid population growth and development, which can greatly affect the thermal environments. The effects of roadside trees and road orientation on the outdoor thermal environment were investigated on four different roads in Kuala Lumpur, Malaysia. Field measurements were conducted to assess outdoor thermal environments, where the selection of sites was based on different roadside tree morphological features and road orientations. Outdoor air temperature (Ta), relative humidity (RH), globe temperature (Tg), wind speed (WS), and wind direction (WD) were measured. Absolute humidity (AH) was estimated based on relative humidity and air temperature. Planting dense canopy trees with an average sky view factor (SVF) of 0.07 reduced the mean radiant temperature (Tmrt) by 35% and the physiological equivalent temperature (PET) by 25%. East–West (E–W) and Northwest–Southeast (NW–SE) oriented roads had high PET values of 41 °C and 43 °C, respectively. North–South (N–S) and Northeast–Southwest (NE–SW) orientated roads had lower PET values (37 °C), providing improved outdoor microclimate. Roadside trees provided greater cooling potential in E–W and NW–SE oriented roads. The findings are useful for urban road design in tropical cities in order to improve the outdoor thermal environment and pedestrian comfort.

ACS Style

Sheikh Ahmad Zaki; Hai Jian Toh; Fitri Yakub; Ahmad Shakir Mohd Saudi; Jorge Alfredo Ardila-Rey; Firdaus Muhammad-Sukki. Effects of Roadside Trees and Road Orientation on Thermal Environment in a Tropical City. Sustainability 2020, 12, 1053 .

AMA Style

Sheikh Ahmad Zaki, Hai Jian Toh, Fitri Yakub, Ahmad Shakir Mohd Saudi, Jorge Alfredo Ardila-Rey, Firdaus Muhammad-Sukki. Effects of Roadside Trees and Road Orientation on Thermal Environment in a Tropical City. Sustainability. 2020; 12 (3):1053.

Chicago/Turabian Style

Sheikh Ahmad Zaki; Hai Jian Toh; Fitri Yakub; Ahmad Shakir Mohd Saudi; Jorge Alfredo Ardila-Rey; Firdaus Muhammad-Sukki. 2020. "Effects of Roadside Trees and Road Orientation on Thermal Environment in a Tropical City." Sustainability 12, no. 3: 1053.