Abdullah O. Bafail’s research while affiliated with King Abdulaziz University and other places

A new coupled global climate model (CGCM) has been developed at the Center of Excellence for Climate Change Research (CECCR), King Abdulaziz University (KAU), known as Saudi-KAU CGCM. The main aim of the model development is to generate seasonal to subseasonal forecasting and long-term climate simulations. The Saudi-KAU CGCM currently includes two atmospheric dynamical cores, two land components, three ocean components, and multiple physical parameterization options. The component modules and parameterization schemes have been adopted from different sources, and some have undergone modifications at CECCR. The model is characterized by its versatility, ease of use, and the physical fidelity of its climate simulations, in both idealized and realistic configurations. A description of the model, its component packages, and parameterizations is provided. Results from selected configurations demonstrate the model’s ability to reasonably simulate the climate on different time scales. The coupled model simulates El Niño-Southern Oscillation (ENSO) variability, which is fundamental for seasonal forecasting. It also simulates Madden-Julian Oscillation (MJO)-like disturbances with features similar to observations, although slightly weaker. The Saudi-KAU CGCM ability to simulate the ENSO and the MJO suggests that it is capable of making useful predictions on subseasonal to seasonal timescales.

Higher education sector in the Kingdom of Saudi Arabia has observed great leaps during the last National development plan (2011–2015) and the new one (2016–2020). The higher education authority always tries to solve the question of conflicting aspects concerning the distribution of preparatory-year students among faculties and departments while respecting available capacity, resources, GPA, and student desires and capabilities. Goal Programming (GP) is considered as one of the most powerful techniques for many applications comprising conflicting objectives. This paper proposes a Mixed Integer Nonlinear Goal Programming Model (MINLIGPM) for solving the problem of admission planning both at the faculty and departmental levels. The model aims to satisfy the required key objectives stated by higher authority related to the distribution of preparatory year students among various faculties and departments in a University. The model is described in a general form that can be adopted for any university taking into considerations its special requirements. The requirements, resources and constraints together with relevant data for the Faculty of Engineering and Department of Industrial Engineering at King Abdulaziz University, Saudi Arabia will be used as a case study. The simple linear GP model can be solved using many computerized software such as: Microsoft Excel Solver add-ins, Linear Program Solver (Tora), QM for Windows. However, such software fails to solve a model such that proposed in this paper. Therefore, an enhanced Differential Evolution (DE) algorithm for solving constrained optimization, named EDECO, will be developed to solve the proposed non-linear integer GP problem. The proposed algorithm introduces a new search mutation to improve both the local search tendency and the global exploration capability, and to accelerate the convergence of DE technique. Besides, adaptive crossover rate and randomized scale factors will be introduced as uniformly random numbers to enhance the population diversity.

This study was conducted in metalwork and woodwork industries in Jeddah Industrial Estate. The purpose of this study was to assess the magnitude of industrial noise exposure and to propose remedial actions. Noise was measured at different times of a day in 28 randomly selected factories and workshops. Results indicated that noise levels varied according to the type and size of a factory, and the type and number of machines used. Mean noise levels in metalwork factories were higher than those in woodwork factories. The highest noise levels were observed while manufacturing cans and forming steel reinforcement for concrete, where noise levels exceed 90 dB(A). All mean noise levels in all studied metalwork factories and in 50% of studied woodwork industries were higher than the standard level of 85 dB(A).

Summer heat in coastal subtropical Jeddah, augmented by heat from operating ground servicing equipment in King Abdul-Aziz International Airport (KAAIA), presents a major occupational problem to ground service operators, particularly the air traffic control coordinator (ATCC), that hinders their work efficiency and induces health disorders to them. The present study was conducted to assess the magnitude of this problem and propose heat control strategy and remedial actions for the Saudi Arabian Airlines (SAUDIA). Heat parameters including air temperature (T (a)), wet bulb temperature (T (w)), globe temperature (T (g)) and air velocity were measured around serviced planes and in other locations used by ATCC, and the WBGT and the ATCC-WBGT-TWAs were computed. Mostly all the T (a) measurements, and many T (w) measurements, were higher than T (a) and T (w) forecasted by the Presidency of Meteorology and Environment (PME) due to heat dissipated from operating vehicles and equipment in service. The measured and PME forecasted parameters have good and medium linear correlations (T (a): r (2) = 0.74 and T (w): r (2) = 0.64). The computed WBGT in the service stations around planes are considerably higher than the 25 and 27.5 degrees C recommended TLV(R) for non-acclimatized and acclimatized operators. However, the computed ATCC- WBGT-TWA levels indicate that the shift-work-schedule which was recommended to be implemented by SAUDIA has successfully reduced their heat exposure to acceptable levels, except for a very few operators (6.7% exceeding WBGT-TLV(R) of 25 degrees C and 2.2% exceeding TLV(R) of 27.5 degrees C) for whom the shift-work schedules might be corrected to achieve safe heat exposure.

Heat stress presents a main problem to Muslim Hajeej (pilgrims) during Hajj (pilgrimage) season, particularly in summer. Records of the Saudi Ministry of Health show close relation between heat casualties and climatic heat load through consequent Hajj seasons. The present study was conducted to evaluate the climatic heat load in Hajj locations during summer of 1995 as well as just before and during the Hajj season of 1997. Heat measurements including: T a, T w, T g, WBGT, relative humidity and air velocity were conducted through July–September 1995, and on March/April 1997, in 10 Hajj locations at morning, noon, afternoon and night. The highest WBGTs were at Haram court, Ghazzah area and Muna housing area, followed by Arafat areas and Muzdalefah, and the lowest at Azizia area. However, all the WBGTs were considerably higher than the ACGIH-TLV® for safe heat exposure, particularly during daytime; meanwhile, heat exposure considerably exceeded the ASHRAE comfort zone at all locations all times. The natural climatic condition is a major contributing factor to the overall heat load; moreover, potentiated by heat dissipated from Hajj activities, including Hajeej crowds, human activities, and the vehicles’ masses exhaust. This situation is further synergized by some pilgrims’ misbehavior (e.g. living in open sunny areas, using vehicles without roofs) and lack of awareness of the seriousness of heat exposure among them. An outline for a control strategy has been suggested based on planting open areas of Arafat and Muna, provision of air conditioned housing and tents in Muna, segregation of pedestrians from vehicles and their provision of shaded roads and rest areas, establishing more water spatters in Arafat and Muna, checking the performance of large vehicles before issuing their permits for operation during Hajj, providing vehicles parking isolated areas away from Hajeej tents, provision of ample amounts of quality drinking water in all Hajj locations, provision of ample optimal ambulance services, and dissemination of educational information to Hajeej for their taking advantage of Fiqh (religion rules) waivers in performing Hajj rituals to minimize their heat exposure, and for their personal protection.

The present work was conducted to define the magnitude of the problem of heat exposure in Jeddah and the role of both the climatic and the industrial factors on the total heat load. Indoor heat exposure was studied in an industrial complex of 5 plants for cables' manufacturing. Outdoor heat exposure was studied in shaded and unshaded operations in Jeddah Islamic Port (JIP). The heat exposure parameters, including air temperature (Ta), wet bulb temperature (Tw), and globe temperature (Tg), as well as the wet bulb globe temperature (WBGT) heat stress index, the relative humidity and the air velocity, were assessed at representative locations. Results of the study indicated that:(a) the levels of heat exposure exceeded the TLV in mostly all the work areas where no air-conditioning is provided. (b) the ambient heat is the factor contributing most to the heat load both in summer and in winter. (c) the radiant heat from furnaces and hot metal rolling and milling adds more heat load to the work environment in specific operations. An outline of a control strategy has been suggested, emphasizing evaporative engineering heat control, work and hygienic practices and auxiliary cooling clothing.

The levelling process of a vast area of land, for irrigation or any other development plan, is usually done in two stages. The first stage starts by determining the levels of the terrain, while the second stage solves the earthwork allocation for the predetermined levels. The most recent attempt, reported in the literature, to find global optimality for this problem was a trial-and-error approach which solves a linear transportation problem for every possible terrain's level and selects the level that results in the lowest transportation cost. This approach, however, being an iterative procedure, can only come closer to the optimum solution depending on how small the iteration steps are, but does not guarantee global optimality. The paper presented here offers a linear programming model that combines the levelling of terrains and the associated transportation in a single linear programming problem, thus guaranteeing global optimality.

In this paper a mathematical model is developed for allocating pre engineering students to available majors at an engineering college . The model considers departments' capacities and students' preferences . Moreover , it gives priority to students with higher Grade Points Averages (GPA) . The model is formulated as a goal programming problem . Its applicability is tested using real data . The model performed significantly better than the manual method presently at use .

Noise presents health and social problems in industrial operations, and is mainly related to machinery used in the industries. The present study was conducted in the different utilities industries in Jeddah Industrial Estate (JIE), in order to assess the magnitude of the problem of industrial noise exposure there in an endeavor to propose remedial controls to the problem. Noise was measured in a random sample of 28 factories, representing 6 activities, at different day times. Results indicated that the noise levels vary, mostly, according to the type of industry and the size of the enterprise and the type and the number of the machinery used. The highest noise exposures exist in the cables, the concrete and the construction supplies, and the glass industries where, mostly, all the recorded dB(A) measurements (Leq, Max SPL and Min SPL) are higher than 85 dB(A), while the lowest exposures exist in the food processing and the dairy products and beverages industries, where all the average Leq dB(A) measurements are lower than 85 dB(A). It has been concluded that such noise pollution can present health problems to the workers, a situation which calls for a rapid planning of strategies for noise control and hearing conservation programs including:  Measuring occupational noise exposure.  Creating noise map of the factories.  Controlling noise wherever is necessary.  Pre-employment hearing tests.  Periodical hearing test programs.