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Alkali activated concretes have emerged as a prospective alternative to conventional concrete wherein diverse waste materials have been converted as valuable spin-offs. This paper presents a wide experimental study on the sustainability of employing waste sawdust as a fine/coarse aggregate replacement incorporating fly ash (FA) and granulated blast furnace slag (GBFS) to make high-performance cement-free lightweight concretes. Waste sawdust was replaced with aggregate at 0, 25, 50, 75, and 100 vol% incorporating alkali binder, including 70% FA and 30% GBFS. The blend was activated using a low sodium hydroxide concentration (2 M). The acoustic, thermal, and predicted engineering properties of concretes were evaluated, and the life cycle of various mixtures were calculated to investigate the sustainability of concrete. Besides this, by using the available experimental test database, an optimized Artificial Neural Network (ANN) was developed to estimate the mechanical properties of the designed alkali-activated mortar mixes depending on each sawdust volume percentage. Based on the findings, it was found that the sound absorption and reduction in thermal conductivity were enhanced with increasing sawdust contents. The compressive strengths of the specimens were found to be influenced by the sawdust content and the strength dropped from 65 to 48 MPa with the corresponding increase in the sawdust levels from 0% up to 100%. The results also showed that the emissions of carbon dioxide, energy utilization, and outlay tended to drop with an increase in the amount of sawdust and show more the lightweight concrete to be more sustainable for construction applications.

The post-occupancy evaluation process is pivotal for assessing the performance of indoor and outdoor living environments after occupation. This evaluation involves a multifaceted analysis, encompassing energy efficiency, indoor environmental quality, outdoor spaces, and occupant satisfaction. Despite the inherent advantages and potential applicability of post-occupancy evaluation in residential buildings, the lack of uniformity in research methodologies, data collection techniques, investigative approaches, and result interpretation has impeded cross-comparisons and method replication. In a concerted effort to enhance the understanding of prevailing post-occupancy evaluation methodologies, this study undertook a comprehensive systematic literature review of post-occupancy evaluation practices within the residential domain from 2000 to 2023. The results unequivocally underscored the pervasive lack of consistency in methodological applications, tool deployment, and data reporting across diverse post-occupancy evaluation investigations. The objectives of this review aimed to examine the existing post-occupancy evaluation (POE) methods, assess occupant-centric thermal comfort, evaluate the impact of POE feedback on building design, and develop recommendations for architects, engineers, facility managers, and policymakers on leveraging POE feedback to enhance thermal comfort and energy efficiency in buildings. This study offers critical insights into advocating for a more standardized and cohesive post-occupancy evaluation approach. The findings of this review can direct the establishment of a coherent and consistently implemented post-occupancy evaluation framework within the realm of residential architecture.

This paper presents a Hybrid Particle Swarm Optimization (HPSO) to solve the Unit Commitment (UC) problem. Problem formulation of the unit commitment takes into consideration the minimum up and down time constraints, start up cost and spinning reserve, which is defined as the minimization of the total objective function while satisfying all the associated constraints. Problem formulation, representation and the simulation results for a 10 generator-scheduling problem are presented. Results shown are acceptable at this early stage.

Load flow and short circuit studies are the two important power system analysis components to ensure the system upgrades, future upgrades and present distribution equipment meeting the present and future requirements. A number of power system analysis softwares are used to perform the analysis. This paper presents the analysis of load flow and short circuit studies of an offshore platform using ERACS software and analyses its performance by comparing with the existing EDSA software results. The EDSA software is commonly used in industries because of its accuracy and reliability while ERACS offers a user friendly with a powerful graphical user interface. The system analysis of an offshore platform, namely TBCP-A is performed to identify the peak load of full load and load shedding condition. The modeling of the TBCP-A network is then carried out using ERACS and the load flow study simulation is performed for three different scenarios, which are normal, maintenance services and emergency condition. The short circuit simulation is executed for two scenarios, namely during load exchange between two transformers and load exchanged between transformer and the emergency diesel generator. From the analysis, it is shown that no voltage violation occurs and all the bus bar ratings are sufficient except for one which is below the short circuit current rating. The ERACS software had produced an acceptable result where the deviation in both analyses is less than 7% between the two soft wares for all scenarios.

The global demand for energy is expected to rise up to 59% by the year 2035. This is due to the increasing technology developments and contemporary industrialization. Continues trends of these simultaneously will affects the crude fossil oil reserves progressively. Therefore, biofuels that are predominantly produced from the biomass based feedstocks such as plant, algae material and animal waste. Liquid or gaseous biofuels are the most simple to ship, deliver, and burn since they are easier to transport, deliver, and burn cleanly. The key contributor to the elevated green house gaseous concentration is carbon dioxide (CO2). Two-thirds of global anthropogenic CO2 emissions are due to fossil fuel combustion, with the remaining third attributed to land-use changes. Interestingly, recent literature has announced that the utilization of liquid biofuels capable of reducing the CO and CO2 emissions. Other positive impacts of the liquid biofuels are; (1) reduce the external energy dependence, (2) promote the regional engineering, (3) increase the Research & Development activities, (4) reduce the environmental effects of electricity generation and transformation, (5) improve the quality of services for rural residents and (6) provide job opportunities.

Abstract Many countries produced biodiesel from crude vegetable oil. However, current vegetable oil feedstock to produce biodiesel slow the growth of biodiesel blend implementation due to the high cost of feedstock production. As a result, waste cooking oil (WCO) is claimed to be economic and readily available without cultivation and highly potential feedstock for high yield biodiesel. In this study, Fe-exchanged montmorillonite K10 (Fe-MMT K10) was employed as a catalyst in converting WCO to biodiesel. In comparison, Fe-MMT K10 was able to produce 95.26% biodiesel, which is higher than biodiesel produced using unmodified MMT K10 as catalyst and reaction without catalyst (38.39% and 29.50%, respectively). The full process of biodiesel production was carried out by response surface methodology (RSM) in conjunction with the central composite design (CCD) for statistically optimization and modelling. From the ANOVA, it was found that the production of biodiesel achieved an optimum level of 92.74% biodiesel at 134.07 °C, under a specific optimized condition of 6.32 h reaction time, 4.68 wt% of catalyst and 11.77:1 methanol to oil ratio.

Abstract Liquid fuels are likely to remain the main energy source in long-range transportation and aviation for several decades. To reduce our dependence on fossil fuels, liquid biofuels can be blended to fossil fuels – or used purely. In this paper, coconut methyl ester, standard diesel fuel (EN590:2017), and their blends were investigated in 25 V/V% steps. A novel turbulent combustion chamber was developed to facilitate combustion in a large volume that leads to ultra-low emissions. The combustion power of the swirl burner was 13.3 kW, and the air-to-fuel equivalence ratio was 1.25. Two parameters, combustion air preheating temperature and atomizing air pressure were adjusted in the range of 150–350 °C and 0.3–0.9 bar, respectively. Both straight and lifted flames were observed. The closed, atmospheric combustion chamber resulted in CO emission below 10 ppm in the majority of the cases. NO emission varied between 60 and 183 ppm at straight flame cases and decreased below 20 ppm when the flame was lifted since the combustion occurred in a large volume. This operation mode fulfills the 2015/2193/EU directive for gas combustion by 25%, which is twice as strict as liquid fuel combustion regulations. The 90% NO emission reduction was also concluded when compared to a lean premixed prevaporized burner under similar conditions. This favorable operation mode was named as Mixture Temperature-Controlled (MTC) Combustion. The chemiluminescent emission of lifted flames was also low, however, the OH* emission of straight flames was clearly observable and followed the trends of NO emission. The MTC mode may lead to significantly decreased pollutant emission of steady-operating devices like boilers, furnaces, and both aviation and industrial gas turbines, meaning an outstanding contribution to more environmentally friendly technologies.

This study seeks to understand how entrepreneurs of SME beach resorts mitigate challenges in their efforts to survive and simultaneously expand their businesses. SMEs in tourism related industry including beach resorts cater towards accommodating increased number of tourist arrivals. Malaysia targets to bring in 36 million tourists, with RM168 billion tourism receipts by the year 2020. The sun, sea and sand are naturally the magnets of tropical islands of Malaysia. The authors employed in-depth interview technique on two resorts located on Perhentian Kecil Island, offshore Terengganu, Malaysia. Observation of the premises complements data collected from interviews. Findings suggest that the resorts employed various strategies to manage their operations. Cost saving methods like employing family members, constructing additional resort features during monsoon period and smart business arrangement with resorts suppliers contributed towards resorts expansion. The study outcome would amongst others benefit policymakers in nurturing the SME sector, further facilitating Malaysia towards a developed nation. This study also contributes to the performance management literature particularly on island beach resorts.