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The utilization of renewable energy to run desalination plants has enormously expanded in the last two decades. In this study, a grid-connected hybrid solar-wind system is proposed to power a small-scale Reverse Osmosis (RO) desalination unit. In a case study, the system's performance has been analyzed under the weather conditions of the Eastern Province, Saudi Arabia. A numerical model has been developed based on a mixed-integer linear programming (MILP) approach to design and size the proposed system. The developed model is solved on an hourly basis to capture hourly variations of weather conditions with the aim to obtain an efficient design to operate the RO plant and supply freshwater to a small community living in a remote area at minimum cost. The developed model allows finding the optimal number of wind turbines, the number of photovoltaic (PV) modules, and the energy purchased from the national grid. Since the desalination energy consumption depends on the feed water conditions, two energy consumption rates are considered, namely, 2 and 4 kWh/m3. The results show that brackish water can be purified for the two different energy requirements at a cost varying between 1.72 and 1.84 $/m3, respectively.

The inadequate risk management of public–private partnership (PPP) projects is a principal cause of project distress or failure. This research seeks to identify and empirically validate measures of effective risk management (ERM) in the context of PPPs in a developing country, a subject that has received scant attention in the extant literature. The research is based on a comprehensive literature review, expert interviews and a questionnaire survey. Mean score ranking and factor analysis were employed to rank and group the identified measures, respectively. Tests were performed to determine the respondents’ agreement and establish the reliability and validity of the survey instrument. Analysis results indicate that all identified measures are important, are distributed over the entire project’s life cycle and exhibit a multi-organizational focus. The most significant measures focus on PPP-specific artifacts and procurement activities that are vital for ERM. Factor analysis established six critical underlying dimensions for the ERM of PPP projects. The extracted factors generally acknowledge the need for expert public- and private-sector project stakeholders with mature organizational structures, business processes and relevant experience to successfully handle and deliver PPP projects. Furthermore, a comprehensive PPP policy and sound legal and regulatory frameworks are essential for supporting the ERM of PPP projects. The findings will enable a better understanding of factors that influence the quality and outcomes of risk management efforts and promote sustainable infrastructure development via PPPs, where the success of a project strongly relies on positively managing a project’s risks in the economic and the social domains.

Saudi Arabia, with no perennial rivers, is considered to be an arid land where water losses in the water distribution network (WDN) supply increase the need for sea water desalination. This paper provides a reliability model to enhance the WDN for a water pumping station in Saudi Arabia. The paper utilizes the fault tree analysis (FTA) reliability tool to mitigate water supply stoppages. In the case under study, the pump station utilizes two groundwater aquifers in the eastern part of Saudi Arabia to meet the raw water demand through a water distribution network (28 km-long pipelines). Data has been gathered from the maintenance history to estimate the system reliability based on the loss of water by which each component of the system is assessed on its contribution to the overall system reliability and water supply. The findings revealed that system availability can be improved by adding a new pump in the booster station which further enhances the availability of the system to 99.99% and saves the WDN more than 740,974.60 gallons of water loss per year. It is hoped that the paper's recommendations will enhance reliability practices in similar water network stations. HIGHLIGHTS The reliability of a community raw water distribution system in Saudi Arabia is assessed.; A reliability tool based on fault tree analysis is utilized to mitigate water supply stoppage.; Real data are collected to estimate system reliability.; The water distribution system availability is analyzed and improved.

In today’s business environment, contributions made by the manufacturing sector to the economy and social development is evident. With a focus on long-term development, the manufacturing sector has adopted advanced operating strategies, such as lean manufacturing, industry 4.0, and green practices in an integrated manner. The integrated impact of circular economy, industry 4.0, and lean manufacturing on sustainability performance has not been adequately addressed and investigated. Therefore, the aim of this study is to investigate the integrated impact of circular economy, industry 4.0, and lean manufacturing on the sustainability performance of organizations in Saudi Arabia. Data were collected through a questionnaire-based survey as a primary data instrument. A total of 486 organizations have responded to the survey within the timeframe. Moreover, the structural equation modeling method is utilized for data analysis through SmartPLS tool for the developed hypotheses of the research. The findings highlight the positive impact of circular economy on the sustainability of the organizations. Furthermore, the results indicate that industry 4.0 and lean manufacturing have positive mediating impacts as enablers for the successful implementation of circular economy toward the sustainable performance of organizations in Saudi Arabia. The study finding confirms that lean manufacturing is a substantial mediating variable that is essential for the successful implementation of industry 4.0 technologies. Moreover, the study indicates the recognition and acknowledgment of companies on circular economy principles, industry 4.0 technologies, and lean manufacturing tools to achieve the desired sustainability.

Construction is prone to disputes similar to other business dealings. Construction delays are the most common causes of disputes in construction projects. Most of the time, construction projects are delayed not only because of a lack of funding, but also because of disputes between the contractor and the client. Blockchain Technologies (BCT) have the potential to make the construction industry more efficient, inexpensive, or completely automated. In this paper, an extensive literature review is conducted to locate authoritative sources about the most common applications of blockchain technology in the construction industry. The study aims to identify the potential, benefits, challenges, and uses of blockchain in the construction industry. Furthermore, this paper explores the roles of BCTs in improving and enhancing the workflow efficiency of construction projects. In addition, this paper identifies the major causes of disputes and delays in the construction industry. These causes were used as the baseline for identifying the most relevant solutions provided by blockchain technologies to develop a matching model to find applicable solutions from the literature cases to resolve the identified causes of disputes and delays. The research findings indicated that the common cases of BCT including administrative purposes, smart contracts for transactions, permanent transaction records, and permanent ownership records contribute to solving the causes of disputes and delays in construction projects. The findings of this paper recommend that both public and private stakeholders in the construction sector adopt blockchain technologies and blockchain-based Building Information Models (BIMs) to improve construction workflows and processes.

In recent years, Carbon Dioxide (CO2) emission has been increased by 22% in Saudi Arabia, and the building construction sector is one of the major contributors to increased CO2. This necessitates Saudi Arabia's introduction of energy efficiency and sustainability in the construction sector. Green Concrete (GC) has recently gained popularity in the Kingdom as it is environmentally friendly and produced from waste and residual materials. However, every new technology faces application challenges that can stymie its adoption in the industry. As a result, this study aims to determine the potential benefits and application challenges of using GC technology in Saudi Arabian's construction industry. This study conducted a comprehensive literature review of the subject followed by a questionnaire survey to field practitioners and interviews with professional experts to determine the potential benefits and application challenges of GC technology. In addition, an analysis of GC trail test documents implemented in a local project and a meeting with the project team were also conducted to determine the trial test's advantages and implementation challenges. The major benefits identified in this study are reduced energy use, waste material reuse, CO2 reduction, natural resource conservation, and reduced landfill numbers, while the major implementation challenges identified in this study are discouraging building codes and a lack of information and understanding of GC benefits. Subsequently, recommendations for government agencies, private sector businesses, and concrete suppliers are provided to improve the benefits of GC, resolve application challenges, and promote and accelerate its adoption in Saudi Arabia.

The unloading of petroleum products is a complex and potentially dangerous operation since the unloading system contains complex interdependency components. Any failures in one of its components lead to a cut in the petroleum supply chain. Therefore, it is important to assess and evaluate the reliability of the unloading system in order to improve its availability. In this context, this paper presents the operation philosophy of the truck unloading system, failure modes of the components within the system, and a bottom-up approach to analyze the reliability of the system. In addition, it provides reliability data, such as failure rates, and mean time between failures of the system components. Furthermore, the reliability of the whole system was calculated and is presented for different time periods. The critical components, which are major contributors towards the system reliability, were identified. To enhance the system reliability, a reliability-based preventive maintenance strategy for the critical components was implemented. In addition, the preventive maintenance scheduling was identified based on the reliability plots of the unloading system. The best schedule for preventive maintenance of the system was determined based on the reliability function to be every 45 days for maintaining the system reliability above 0.9. Findings reveal that the reliability of the unloading system was significantly improved. For instance, the system reliability at one year improved by 80%, and this ratio increased dramatically as the time period increased.

The purpose of this article is to develop a mathematical optimization model for the optimal design of a cause selecting chart (CSC) for a real manufacturing case. The X¯ and CSC charts are designed...

In production-inventory control, economic order quantity (EOQ) and economic production quantity (EPQ) models are used to determine the optimal order quantities for purchasing and manufacturing. Most EOQ and EPQ models are constructed assuming constant costs. Recently, however, EOQ/EPQ models assuming varying costs (i.e., holding, ordering, and purchasing costs) have been receiving considerable attention. The objective of this paper is to review and classify EOQ and EPQ inventory models formulated under the assumption of variable holding costs. The relevant papers are reviewed and classified into three main types: time-dependent holding cost, stock-dependent holding cost, and multiple dependence or other holding cost variability. Additional classification is proposed for the reviewed models according to their objectives, solution methods, and applications. The paper identifies research trends and includes several suggestions for future research directions.

Plastic and petrochemical industries are lagging behind in terms of environmental sustainability performance because of the nature of these industries. Although plastic and petrochemical industries have adopted lean manufacturing and/or Industry 4.0 technologies, more efforts are needed to enhance sustainable development. The purpose of this study is to explore the integrated impact of Industry 4.0 technologies and lean manufacturing on the sustainability performance of plastic and petrochemical industries in Saudi Arabia. Moreover, it investigates the casual relationship between Industry 4.0 technologies and sustainability performance as well as the direct linkage between Industry 4.0 and lean manufacturing. A questionnaire is used as the primary instrument for collecting data from 112 plastic and petrochemical organizations. A hypothesized relationship is formulated and then analyzed using the structural equation modeling (SEM) approach. The outcome of the analysis shows that Industry 4.0 and lean manufacturing have a positive impact on sustainability performance. The study also presents a list of valid constructs for Industry 4.0 technologies, lean manufacturing, and sustainability performance. Furthermore, the study shows that the plastic and petrochemical industries in Saudi Arabia acknowledge and recognize the contribution of Industry 4.0 technologies and lean manufacturing principles to the protection of the environment as a dimension of sustainability performance.

Greenhouse gasses are by-products of using fossil fuels to generate energy. It is known that climate change is caused by an increase in greenhouse gasses in the Earth's atmosphere. Solar energy is a renewable energy source that is an environmentally friendly resource for generating power. The photovoltaic (PV) system is a well-established technology for transforming solar energy into electric power. Sizing-decisions of a PV system is a strategic decision-making process that has a long-term impact on the project. This work proposes a multi-objective optimization (MOO) model for sizing-decisions of a grid-connected PV system. The objectives consider the economic aspect in terms of minimizing the project lifespan costs and non-economic aspects, including maximizing system reliability and reducing CO2 emissions. The sizing decisions are the number of PV panels, the amount of energy purchased from the main grid, and the amount of energy supplied to the main grid. In addition to a binary variable for an either-or decision, either purchase or supply from the grid. The model generates Pareto-optima to assist the decision-maker in assessing trade-offs between alternatives. A case study based on monthly demand for the residential area at King Fahd University of Petroleum & Minerals (KFUPM) is provided to clarify the practicality of the model. It is found that 1713 PV modules are required to meet annual demand at an annual cost of M$1.61 over 25 years.

Oil and gas companies play an important role in the global economy since they supply a large portion of the necessary energy to the world. The optimal production of oil and gas should be performed in an integrated fashion for the whole supply chain. The downstream oil and gas supply chain (OGSC) has attracted the interest of many researchers due to its central role in the world economy. This paper develops an integrated multi-objective OGSC model for medium-term tactical decision making for the OGSC downstream segment. The selected objectives related to downstream activities are the following: minimize the total cost, maximize the total revenue, and maximize the service level. The model includes multi-period and multi-product inputs. The model is verified and solved using an improved augmented e-constraint algorithm to generate Pareto optimal solutions. The model assists in assessing various trade-offs among different objectives and guides decision makers for the effective management of the downstream OGSC. The utility of the proposed model is demonstrated using a real case from a Saudi Arabian downstream OGSC. Sensitivity analysis is conducted to investigate the effects of input parameters on the set of Pareto optimal solutions. The model is expected to have a positive impact on the future management of this important component of the energy sector.

The need for resilience and an agile waste management system in Saudi Arabia is vital to control safely the rapid growth of its municipal solid waste (MSW) with minimal environment toll. Similarly, the domestic energy production in Saudi Arabia is thriving and putting a tremendous pressure on its huge reserves of fossil oil. Waste to energy (WTE) plants provides a golden opportunity for Saudi Arabia, however, both challenges (MSW mitigation and energy production) are usually looked at in isolation. This paper at first explores the potential of expanding the WTE energy production in the eastern province in Saudi Arabia under two scenarios (complete mass burn with and without recycling). Secondly, this study analyzes the effect of 3Rs (reduce, reuse, recycle) practices implementation in a residential camp (11,000 population) to influence the behavior of the camp&rsquo, s citizens to reduce their average waste (kg/capita). The results of the 3R-WTE framework show a potential may reach 254 Megawatt (MW) of electricity by year 2030. The 3R system implementation in the camp reduced MSW production from 5,625 tons to 3000 tons of household waste every year, which is considered lower than what the surrounding communities to be produced in the same area.

In the present study, the influence of processing parameters of friction stir welding on the corrosion rate of the welded joints of aluminium SiC–Gr hybrid composites was investigated. The experimental results indicate that the corrosion resistance of the welded joints increases at high welding (traverse) speed and/or low values of rotational speed. These variations occur as a result of the changes in the joint microstructure, where fine grains are developed as a consequence of a relatively low heat input and fast cooling to room temperature by ambient air associated with low rotational speed and/or high welding speeds. The mixed electrode theory is used to explain these variations of the corrosion rate, where the area ratio of cathode/anode for the galvanic couple between the aluminium metal matrix and the reinforcement constituents becomes small for fine grains. Thus, the corrosion resistance of the welded joints is increased.

To clarify the role of pin profile geometry on some properties of friction stir welded of the considered aluminum matrix composites (Al-4 wt% Mg, reinforced with 1 wt% SiC and 1 wt% graphite particles) plates of 8 mm thickness were fabricated by compocasting method then annealed at 400°C for 2 h. Tools with different pin profiles (square, hexagonal, and octagonal) were manufactured to be used for friction stir welding (FSW) of aluminum matrix composites plates at four different levels of welding (transverse) and rotational speeds. The effects of these pin profiles on microstructure and some mechanical properties of the friction stir welded joints were studied. The results show that the plates welded by square head pin have better properties compared to the other pin profiles. This pin seems to cause better grain refinement and redistribution of SiC and graphite particles in the welded nugget zone (NZ) than the other two types. This has led to better improvements in the considered mechanical properties. Al...

In this study, the effect of friction stir welding (FSW) parameters such as rotational speed, welding (transverse) speed, and the type of pin profile tool on some mechanical properties was statistically investigated. Plates of aluminium matrix composites fabricated by stir casting method were joined by friction stir welding process. The statistical analysis has shown that the most important factor affecting hardness and tensile strength is the welding (transverse) speed, while the rotational speed has a second ranking and pin profile tool geometry is the least. The rotational speed has no statistical significant influence on the wear rate. However, the nugget zone, which was welded by square pin profile tool, seemed to exhibit better mechanical properties compared to those obtained by other pin profile tools.