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The visualisation and quantification of pore networks and main phases have been critical research topics in cementitious materials as many critical mechanical and chemical properties and infrastructure reliability rely on these 3D characteristics. In this study, we realised the mesoscale serial sectioning and analysis up to ∼80 μm by ∼90 μm by ∼60 μm on portland cement mortar using plasma focused ion beam (PFIB) for the first time. The workflow of working with mortar and PFIB was established applying a prepositioned hard silicon mask to reduce curtaining. Segmentation with minimal human interference was performed using a trained neural network, in which multiple types of segmentation models were compared. Combining PFIB analysis at microscale with X-ray micro-computed tomography, the analysis of capillary pores and air voids ranging from hundreds of nanometres (nm) to millimetres (mm) can be conducted. The volume fraction of large capillary pores and air voids are 11.5% and 12.7%, respectively. Moreover, the skeletonisation of connected capillary pores clearly shows fluid transport pathways, which is a key factor determining durability performance of concrete in aggressive environments. Another interesting aspect of the FIB tomography is the reconstruction of anhydrous phases, which could enable direct study of hydration kinetics of individual cement phases.

We consider a no-wait m-machine flowshop scheduling problem which is common in different manufacturing industries such as steel, pharmaceutical, and chemical. The objective is to minimize total tardiness since it minimizes penalty costs and loss of customer goodwill. We also consider the performance measure of total completion time which is significant in environments where reducing holding cost is important. We consider both performance measures with the objective of minimizing total tardiness subject to the constraint that total completion time is bounded. Given that the problem is NP-hard, we propose an algorithm. We conduct extensive computational experiments to compare the performance of the proposed algorithm with those of three well performing benchmark algorithms in the literature. Computational results indicate that the proposed algorithm reduces the error of the best existing benchmark algorithm by 88% under the same CPU times. The results are confirmed by extensive statistical analysis. Specifically, ANOVA analysis is conducted to justify the difference between the performances of the algorithms, and a test of hypothesis is performed to justify that the proposed algorithm is significantly better than the best existing benchmark algorithm with a significance level of 0.01.

The quality of engineering education has been improved by the accreditation criteria established by credentialing agencies. As a result, the Industrial and Management Systems Engineering program at Kuwait University has been maintaining accreditation by the Engineering Accreditation Commission of the Accreditation Board for Engineering and Technology for over 15 years. Since the assessment process needs to be thorough and simple at the same time, this paper explains how the Industrial and Management Systems Engineering program at Kuwait University designed and implemented an efficient and effective process for the establishment and assessment of the new Student Outcomes required by the Engineering Accreditation Commission of the Accreditation Board for Engineering and Technology. All the seven new Student Outcomes specified by Criterion 3 of the accreditation requirements are shown to be satisfied by using four different assessment tools, two of which are direct and the other two are indirect. All the results have been statistically verified by using hypothesis testing with a significance level of 0.01. The paper presents a simple and practical assessment method which can be used by other engineering programs that are in the process of implementing the new Student Outcomes.

We address the four-machine flowshop scheduling problem with the objective of minimizing makespan with uncertain processing times The problem was addressed in the literature (RAIRO Operations Research 54, 529-553) and different algorithms were proposed. In this paper, we propose a new algorithm for the problem. The new proposed algorithm is compared with the best algorithm in the literature by using extensive computational experiments. Computational experiments indicate that the new proposed algorithm performs much better than the best algorithm in the literature in terms of error while both have the same computational time. Specifically, the new proposed algorithm reduces the error of the best existing algorithm in the literature over 40%. This result has been confirmed by using tests of hypotheses with a significance level of 0.01.

Highly pure nanosilica was synthesized through a facile hydrometallurgy-based method from silicomanganese slag as a low cost silica source. The synthesis route included short-term nitric acid dissolution at room temperature, gelation, washing, drying, and calcination steps. The experimental dissolution conditions resulted in a dissolution efficiency of 98%. The crystalline structure, chemical composition, chemical bonding, microstructure and elemental analyses, particle size distribution, and surface area of the extracted silica were then studied by appropriate characterization techniques. The characterization findings indicated that the amorphous silica particles had a microporous nature with an average particle size of ~24 nm, exhibiting a high purity of more than 99% and a high specific surface area of ~474 m2 g−1. The overall results indicated that the proposed synthesis route is a promising feasible alternative method to produce highly pure microporous nanosilica from a low cost secondary resource. The proposed method can treat 98% of the slag and uses less chemicals than conventional methods and is therefore a greener nanosilica production process. The current process also competes with the traditional process and other recently introduced processes in terms of process economy and the quality of the produced product.

The four-machine flowshop scheduling problem is investigated with the objective of minimizing total completion time. Job processing times are uncertain where only the lower and upper bounds are known. This problem is common in some manufacturing environments. Some mathematical (dominance) relations are established, and an algorithm (with ten scenarios) is proposed. The proposed algorithm converts the four-machine problem to a single machine problem for which an optimal solution is known for the deterministic problem. The difference among the scenarios is related to the weights assigned to the lower and upper bounds of processing times on the machines. The proposed algorithm is further improved by the established mathematical relations and are evaluated based on extensive computational experiments. The computational results indicate that three scenarios of the proposed algorithm perform much better than the others, and the errors of these three scenarios get better as the size of the problem increases. The results are statistically verified by constructing the confidence intervals.

The two-machine flowshop scheduling problem to minimize total completion time with separate set-up times is addressed. Set-up times are modelled as uncertain within an interval where only the lower...

We consider the four-machine flowshop scheduling problem to minimize makespan where processing times are uncertain. The processing times are within some intervals, where the only available information is the lower and upper bounds of job processing times. Some dominance relations are developed, and twelve algorithms are proposed. The proposed algorithms first convert the four-machine problem into two stages, then, use the well-known Johnson’s algorithm, known to yield the optimal solution for the two-stage problem. The algorithms also use the developed dominance relations. The proposed algorithms are extensively evaluated through randomly generated data for different numbers of jobs and different gaps between the lower and upper bounds of processing times. Computational experiments indicate that the proposed algorithms perform well. Moreover, the computational experiments reveal that one of the proposed algorithms, Algorithm A7, performs significantly better than the other eleven algorithms for all possible combinations of the number of jobs and the gaps between the lower and upper bounds. More specifically, error percentages of the other eleven algorithms range from 2.3 to 27.7 times that of Algorithm A7. The results have been confirmed by constructing 99% confidence intervals and tests of hypotheses using a significance level of 0.01.

The interfacial transition zone (ITZ) in a concrete microstructure is a region of high porosity and low binding materials at the interface of cement paste and aggregate that causes significant reduction in compressive and flexural strengths and considerable increase in permeability of the concrete. Extensive research activities have been devoted to reduction of the ITZ, to avoid its negative effects on concrete properties. This research introduces reactive aggregate concrete (RAC), formed by partial replacement of natural aggregate with Portland cement (PC) clinker of the same size as a reactive aggregate in the concrete mix to reduce the ITZ and improve the concrete properties. After determining the optimum replacement level based on 28 and 60 d compressive strengths, the developed RAC was characterised by measuring its workability, setting time, compressive and flexural strengths, for varying age, water absorption, open-pore volume and chloride penetration depth. Microstructural studies of the ITZ were also performed using scanning electron microscopy. In all measurements, normal concrete was also considered for comparison purposes. The results confirm 121% and 33% enhancement in 7 and 90 d compressive strengths accompanied with 53, 19 and 22·4% reductions in 28 d chloride penetration depth, open-pore volume and water absorption, respectively.

We address a two-machine no-wait flowshop scheduling problem with respect to the performance measure of total completion time. Minimizing total completion time is important when inventory cost is of concern. Setup times are treated separately from processing times. Furthermore, setup times are uncertain with unknown distributions and are within some lower and upper bounds. We develop a dominance relation and propose eight algorithms to solve the problem. The proposed algorithms, which assign different weights to the processing and setup times on both machines, convert the two-machine problem into a single-machine one for which an optimal solution is known. We conduct computational experiments to evaluate the proposed algorithms. Computational experiments reveal that one of the proposed algorithms, which assigns the same weight to setup and processing times, is superior to the rest of the algorithms. The results are statistically verified by constructing confidence intervals and test of hypothesis.

In this study, to investigate the effects of organoclay nanoparticles on the properties of latexes as a cement additive, two kinds of acrylate latexes, poly(styrene-co-butyl acrylate-co-metacrylic ...

Continuous improvement of an engineering program is essential and a critical process. Development and implementation of such a process is not only required by the Accreditation Board for Engineering and Technology (ABET), but it is also a necessary condition for the maturation and development of any engineering program. This paper describes the process employed by the Industrial and Management Systems Engineering (IMSE) program at Kuwait University to continuously improve its program. The employed process includes identification of the lowest score among the seven student outcomes specified by ABET. Next, the courses in the IMSE curriculum addressing this student outcome are identified, and the instructors teaching these courses took remedial actions. In the following semesters, this outcome was measured, and it was found that there is a significant improvement on this outcome. Other engineering programs can benefit from the process described in this paper.

This work presents green lightweight reactive powder concrete (GLRPC) as a novel lightweight composite with improved properties by incorporating modified expanded polystyrene beads (MEPS) i...

Aluminum black dross (ABD) is a solid waste of aluminum smelting process that causes serious environmental and public health problems. In addition, it imposes significant disposal costs to the aluminum industry. In this study, synthesis and characterization of mesoporous alumina (MA) from the ABD using a novel recycling procedure consisting of leaching at low temperature (85 °C) and atmospheric pressure, co-precipitation, separation through selective dissolution, re-precipitation, aging and finally calcination at 600 °C for 2 h. No hard or soft template was used during the formation of the gel. The as-synthesized MA had a specific surface area, total pore volume and average pore diameter of 123–162 m2/g, 0.37 cm3/g and 10.6 nm, respectively which were obtained by nitrogen sorption analysis. The as-synthesized MA possessed more than 98% purity. Its XRD pattern exhibited the characteristic peaks of gamma, eta, theta, and delta phase alumina. FESEM and TEM analyses revealed nanoscale morphology of the as-synthesized MA; having crystal size of ∼11 nm. The TGA analysis showed that the as-synthesized MA is thermally stable and exhibits only ∼5 wt% mass loss for heating from 30 to 800 °C. The characterization of solid residue at the end of the proposed process proved that it contains mainly silica phase which can alternatively be reused as filling agent or aggregate in concrete materials applications. It is quite clear that the process of production of MA from the ABD is feasible and practical and provides a novel mitigation to the environmental problems of the ABD.

The present work evaluates 2-year durability performance of geopolymer cement (GC) mortar derived from a blend of low calcium fly ash and calcium aluminate cement in hydrochloric and sulfuric acid ...

This study deals with the synthesis of TiO2-based nano-adsorbents and their performance in methylene blue adsorption. Nano-adsorbents were made up of micronized powder of anatase TiO2 as a relatively low-cost precursor and a compound alkaline solution containing 5 mol of NaOH and 5 mol of KOH. To synthesize nano-adsorbents, the hydrothermal method was used at three different temperatures of 110, 155, and 200 °C and two calcination temperatures of 450 and 700 °C. The results of methylene blue adsorption tests indicated that the nano-structure synthesized at 155 °C was of maximum adsorption capacity and calcination process resulted in a significant decrease in adsorption capacity. This meso-porous nano-adsorbent was characterized by such techniques as Scanning Electrom Microscopy (SEM), Transmission Electron Microscopy (TEM), Field-Emission Scanning Electron Microscopy (FESEM), X-ray Diffractometry (XRD), Brunauer-Emmett-Teller (BET) analysis, Barrett-Joyner-Halenda (BJH) analysis, and Fourier-Transform Infrared (FTIR) spectroscopy. Pseudo-first-order and pseudo-second-order adsorption kinetics, as well as the Weber and Morris model, were then used to conduct a kinetic study. The adsorption kinetics was also analyzed with three adsorption isotherm models—i.e., Langmuir, Temkin, and Freundlich. The obtained results suggested that the nano-adsorbent exhibiting the maximum adsorption capacity of 96 mg/g was well fitted to the pseudo-second-order model with a correlation coefficient of 0.9938. The findings also showed that the Freundlich model with a correlation coefficient of 0.9592 was the most compatible adsorption isotherm model for this nano-adsorbent.

The performance of geopolymer cement based on blend of waste-glass powder and calcium aluminate cement in pH = 3 of HCl and H2SO4 solutions for 24 months were investigated and compared to Portland cement and high alumina cement mortars as reference. The residual compressive strength and mass loss were monitored at different time intervals, and the reaction products were characterized by XRD, FTIR spectroscopy and SE microscopy to quantify the compositional and microstructural changes. The findings revealed that geopolymer cement possessed superior acid resistance compared to references. H2SO4 attack caused more deterioration than HCl attack due to the accelerating effect of gypsum formation.

A senior design course provides engineering students the opportunity to identify, formulate, and solve complex real-world engineering problems. This outcome is one of the seven student outcomes adopted by The Accreditation Board for Engineering and Technology (ABET). Therefore, the senior design course is a part of the curriculum of most of the international engineering programs. Hence, it is also a required course in the curriculum of the Industrial and Management Systems Engineering (IMSE) program of Kuwait University (KU). In the senior design course of IMSE program at KU, students select a company and conduct their project at the company. In this paper, three of these companies are briefly described along with identified problems, proposed solutions, and obtained results. Student evaluation by the company’s representatives is also discussed. It has been shown that the senior design students improved the operations of the selected companies significantly. It has been also observed that the students are enthusiastic by applying the methodologies and tools of Industrial Engineering that they learned in their earlier courses to solve real life problems.

Nano-tube array is one of the most important types of titanium dioxide-based nanostructures that attracted researchers' attention because of its superior photocatalytic properties. In this research, a thin layer of a titanium dioxide nano-tube array was first prepared by a two-step electrochemical anodizing process by using a titanium sheet. The synthesized nano-tube array was then calcined to obtain a good crystalline structure for enhanced photocatalytic properties. The length, diameter, and thickness of the nano-tubes were measured using SEM imaging technique. In order to enhance the photocatalytic properties, the synthesized nano-tube array was then doped individually with three different chemicals including silver nitrate, potassium ferricyanide and copper sulfate using the chemical bath deposition technique. The photocatalytic properties of the synthesized nano-tube array and the doped samples were evaluated and compared by photoelectrochemical water splitting. The results show that the nano-tube array doped with copper sulfate increases the rate of hydrogen production by up to three times producing as much as 21.65 mmol after 5 h.

By finding appropriate recycling approaches, the volume of wastes, corresponding disposal cost, and the pollution of environment could be diminished. Also, such promising approaches can result in the conservation of natural sources and economic benefits. Aluminum dross as a hazardous solid waste in aluminum production industries has caused serious environmental and public health challenges. Various methods have been introduced for management, utilization, and recycling of the waste. The present review describes, firstly, different types of aluminum dross, their environmental and health hazards, composition, and production process and then focuses on the direct and indirect recycling approaches and recovery strategies.

We consider the two-machine no-wait flowshop scheduling problem to minimize maximum lateness, where setup times are considered separate from processing times. Moreover, setup times are uncertain (within some intervals), where only lower and upper bounds are known. The objective is to obtain a set of dominating schedules, which contain the optimal solution. The size of dominating set can be reduced by the development of dominance relations. In this paper, we establish local and global dominance relations. Furthermore, we provide examples to illustrate how the developed dominance relations either help in finding the optimal schedule or in reducing the size of dominating set. Moreover, we establish an algorithm to find the number of developed dominance relations for given input parameters. Computational experiments indicate that the established dominance relations are helpful in reducing the size of dominating schedules.

This work investigates the effects of both soluble and insoluble chemical activators and quality improvers on hydraulic activity of ground granulated blast-furnace slag-blended Portland cement. An optimum mix consisting of 48% Portland cement, 43% slag and 9% insoluble chemical activator was firstly opted based on 28-, 60- and 120-day compressive strengths. In the next stage, different soluble non-chlorine chemical activators of the type mild alkaline and two different quality improvers including triisopropanolamine and triethanolamine (TEA) were added to the optimum mix to enhance its hydraulic activity. The experimental results showed that the addition of 0.04% TEA resulted in about 8% increase in both 28- and 60-day compressive strengths. Non-chlorine soluble chemical activators, however, when used individually or in combination with quality improvers did not result in higher compressive strengths. Complementary studies by scanning electron microscopy and X-ray diffractometry on 60-day cured hardened paste of the material showed that the microstructure is composed of an amorphous matrix in which non- or partially reacted slag particles are embedded.

We consider the m-machine no-wait flowshop scheduling problem with respect to two performance measures; total tardiness and makespan. Our objective is to minimize total tardiness subject to the constraint that the makespan is not larger than a given value. We develop dominance relations and propose an algorithm, called Algorithm AA, which is a combination of simulated annealing and insertion algorithm. Moreover, we adapt five existing algorithms, including three well performing algorithms known to minimize total tardiness, to our problem. We conduct extensive computational experiments to compare the performance of the proposed Algorithm AA with the existing algorithms under the same CPU times. We also evaluate the effect of the dominance relations. The computational analysis indicates that the proposed Algorithm AA performs significantly better than the existing algorithms. Specifically, the relative error of the Algorithm AA is about 60% less than that of the best algorithm among the five existing algorithms considered. All the results are statistically verified. Hence, the proposed Algorithm AA is recommended for the considered problem.