Journal of Sustainable Engineering (SUSTEN)

Ultrahydrophobic Surface for Water Treatment by Membrane Processes-Prediction of Water Contact Angle on Air/Solid Composite Surface by Solving Young-Laplace Equation

Takeshi Matsuura — 2025-04-07

The evaluation of contact angle (CA) of air-solid composite surface is growing in its importance in membrane separation technology. The reason is that the super-hydrophobic property of the surface allows self-cleaning of membrane surface in various membrane separation processes and also mitigates pore wetting, which is considered the serious disadvantage of membrane distillation. The Cassie-Baxter equation is currently considered one of the best tools to evaluate CA of the air-solid composite surface. However, most of the experimental works of CA measurement were carried out by the sessile drop method, in which the size of the droplet is limited to micro- or submicrometer range, and it is not known how CA is affected by the air content of the air-solid composite surface especially when the droplet size is in a range of millimeter. In this work, the meniscus shape of a large water droplet with a size greater than the capillary length (2.713 mm) was calculated for different air contents at the air-solid surface by solving the Young-Laplace differential equation. It was concluded that the effect of f_s(fraction of solid surface) on CA does not depend significantly on the droplet size, even though the droplet flattens considerably as the droplet size increases.

Factors Affecting the Implementation of Total Quality Management (TQM) in Contractors

Fihman Zulkarnain — 2025-03-27

Maintaining quality in construction projects is critical to project success, which is achieved through total quality management (TQM) techniques. Total quality management (TQM) is a systematic management technique for developing a process-driven culture within an organisation to achieve quality and customer satisfaction. Contractors, as the main actors in this industry, have a central role in ensuring the quality and success of a construction project. Thus, it is essential to identify the factors that influence the implementation of TQM to determine which factors can improve construction quality from the contractor's perspective. Therefore, this study aims to identify, rank, and analyse the factors that influence TQM implementation in North Moluccas contractor companies. A case study approach was utilised, and a survey data was collected from 96 respondents. Validity and reliability tests were conducted to ensure each indicator was valid and reliable. Relative Importance Index (RII) was used to identify factors affecting TQM implementation. As a result of the RII analysis of the 11 research variables, the most critical factor affecting the implementation of TQM based on all respondent groups (directors, site managers, quality control, and field implementers) was teamwork with an RII value of 0.820, identified as the most crucial factor. Despite the critical factor identified, all contributing factors significantly influence successful performance.

Evaluating the Integration of Sustainability Concepts in Plant Design Projects within the Chemical Engineering Programme at Universiti Malaysia Sabah

Chi-Ming Chu — 2025-04-28

This paper presents a brief evaluation of the Capstone Chemical Engineering Design Courses, Plant Design Project I & II, offered in the fourth and final year of undergraduate study at Universiti Malaysia Sabah. One main focus is to identify the elements of sustainability as concepts delivered in the courses to align with United Nations’ Sustainability Goals and the latest Engineering Accreditation Standard (2024). Though the concept of sustainability is not explicitly measured, it is found to be substantially linked to the criteria for selecting alternative designs and optimisation of the final design in the project. Strengths and weaknesses of the courses are discussed, with reference to five institutions’ concepts and pedagogy on sustainability, along with recommendations for improvements in the courses in the near future. According to a study by one of the institutions, the subject of process control requires particular attention when designing a plant, as it is highlighted by professional engineers as pivotal in optimising plant operation for sustainability.