Efficient business organizations must balance quality, cost, and time constraints in competitive environments. Reflecting the complexity of this task, we consider manufacturing systems including several stages of production chains requiring time measurement. When production scheduling is not prioritized in such enterprises, several negative effects may occur. A corporation may suffer financial penalties as well as negative brand exposure, and thus may find its credibility challenged. Therefore, in this study, we propose constructive methods to minimize a total tardiness criterion, considering preventative maintenance constraints to reflect the reality of industrial practice, focusing on a no-wait flowshop environment in which jobs are successively processed without operational interruptions. In addition to proposing constructive methods to solve the no-wait flowshop production scheduling problem, a metaheuristic is presented as an approach to improve results obtained by constructive methods. Computational experiments were designed and performed to compare several production scheduling algorithms. Among various constructive heuristics considered, an algorithm called HENLL using an insertion logic showed the best performance. The proposed metaheuristic is based on the iterated greedy (IG) search method, and the results obtained demonstrated significant improvement compared to the heuristics alone. It is expected that this study may be used by production planning and control (PPC) professionals to apply the proposed method to schedule production more efficiently. We show that the proposed method successfully presented a better solution in relation to total tardiness, considering the above mentioned environment.

A flat Aluminum specimen with a geometric discontinuity, which allows testing of the applicability of 2D and 3D Digital Image Correlation Strain measurements, has been considered for this research since it is prone to high stress concentration via Addis Ababa Institute of Technology research interest. Experimental strain using digital image correlation and geometry measurements should be measured with estimated material properties and compare the results with theoretical model predictions. Aluminum plate with central hole were subjected for far field stress in the Machine shop of School of Mechanical and Industrial Engineering at Addis Ababa University in order to test the agreement between DIC’s strain analysis, strain gauge strain analysis and calculated empirical formulas of strain analysis and for the stress distribution of the plate elastically deformed by using VIC-3D and strain gauge. The aim is to measure vertical strain field, Vertical strain along horizontal line through hole center as function of applied loading and vertical strain using theoretical formula along same line as measurements in a plate with central hole subjected to far field and near field tensile loading using visual image coloration (VIC-3D) software, Destensometere device and solid mechanics equations to compare strain results.

Transnational producers facing the present-day competitive global supply-chain environments need to pursue the most appropriate manufacturing scheme, quality screening task, and stock shipping plan to satisfy customer’s timely multi-item requirements under minimum overall product fabrication-delivery expenses. This study develops a producer-retailer incorporated multi-item two-stage economic production quantity- (EPQ-) based system with delayed differentiation, expedited-rate for common parts, multiple deliveries plan, and random scrap. It aims to assist current manufacturing firms in achieving the aforementioned operating goals. Mathematical methods help us build an analytical model to explicitly portray the studied problem’s features and derive its overall system expenses. Hessian matrix equations and optimization approaches help us prove convexity and derive the cost-minimized fabrication- delivery decision. This study gives a simulated example to illustrate the research outcome’s applicability and the proposed model’s capabilities numerically. Consequently, diverse crucial information becomes obtainable to the manufacturers to facilitate various operating decision makings as follows: (i) the cost-minimized fabrication-delivery policy; (ii) the behavior of system’s overall expenses and operating policy regarding mean scrap rate, and different relationships between common part’s values and completion-rate; (iii) the system’s detailed cost components; (iv) the system’s overall expenses, utilization, and common part’s uptime concerning different common part’s expedited rates; and (v) the collective effects of critical system features on the overall expenses, uptime, and optimal cycle length, etc.

Concrete is the most significant source of construction in the construction industry of the world. However, concrete causes excessive production of cement, which is one of the key contributors of carbon dioxide emissions to the environment. To minimize the use of cement in concrete, various innovative materials are being added in concrete to make it sustainable. In this study, a comparative study between three fibers Carbon Fiber, Glass Fiber, and steel fibers was done to determine which one is the most suitable fiber. For this purpose, testing on specimens was done for tensile and compressive strength at 0.5% addition of each fiber. Testing was done after 3, 7, 14, and 28 days of curing. The results spelled out that the highest compressive strength of 37.53 MPa of cube specimens was found in carbon fiber after 28 days, and Glass fibers exhibited the lowest gain in strength at about 32.335 MPa. Carbon Fiber gained 28% more strength than the control mix. On the other hand, tensile strength was also found highest in carbon fibers i.e. for the cubes the maximum difference between different fibers inducted concrete samples is 28% approximately, and for cylinders it is 27%, respectively. On the other hand, the highest tensile strength of concrete was also gained with the carbon fiber at about 3.61 MPa. The same was found lowest in glass fiber at 3.12 MPa. Carbon fiber got about 44 % improvements in tensile strength.

The vehicle routing problem is widespread in terms of optimization, which is known as being NP-Hard. In this study, the vehicle routing problem with capacity constraints is solved using cost- and time-efficient metaheuristic methods: an invasive weed optimization algorithm, genetic algorithm, savings algorithm, and hybridized variants. These algorithms are tested using known problem sets in the literature. Twenty-four instances evaluate the performance of algorithms from P and five instances from the CMT data set group. The invasive weed algorithm and its hybrid variant with savings and genetic algorithms are used to determine the best methodology regarding time and cost values. The proposed hybrid approach has found optimal P group problem instances with a 2% difference from the best-known solution on average. Similarly, the CMT group problem is solved with about a 10% difference from the best-known solution on average. That the proposed hybrid solutions have a standard deviation of less than 2% on average from BKS indicates that these approaches are consistent.

In this study, the delamination resistance of carbon fiber reinforced polymers (CFRP) consolidated with titanium alloy at the interface between the metal and composite was investigated experimentally and numerically. End-notched flexure (ENF) tests were performed to assess the fracture toughness (GIIC) for Mode II crack expansion of Ti6Al4V titanium alloy/CFRP composite parts. The EFN test is applied to Ti6Al4V-carbon fiber/low melt poly (aryl ether ketone) (CF/LM-PAEK) and Ti6Al4V-carbon fiber/poly (ether ketone ketone) (CF/PEKK) composites with the [0°]24 stacking sequence of unidirectional (UD) fibers. Experimental results indicate that the LM-PAEK composites exhibited Mode II strain energy release rate values 27.64 % higher than those of the PEKK composites. The finite element simulation by LS‐DYNA shows good correlations with the experimental results, with an average error of 5.44 % for the PEKK and 10.58 % for the LM-PAEK, respectively.

The fatigue behavior study on laminated glass/epoxy composite plates at elevated temperature is attempted in the present research work. INSTRON 8862 servo-electric universal testing machine with hydraulic suspension is utilized to perform low cyclic tension-tension fatigue tests at 0.5Hz and 0.7Hz frequencies. Bluehill universal software compatible with INSTRON 8862 is employed to obtain the relationship of fatigue stress upon cycles to failure (S – N) for each specimen. The parametric investigation is done for the loading frequency, lamination sequence and number of layers to understand their effects on fatigue behavior of composite laminated plates under ambient and thermal environment. The elicited results lead to the conclusion that above parameters greatly influenced the fatigue behavior of composite laminated plates under thermal loading. The rising temperature has significant adverse effects on fatigue life. The present research is beneficial for the analysis and design of laminated composite plate or plate-like structures in the domain of fatigue analysis.

Sustainable tourism is known as an effort to prevent the negative impacts of tourism development by considering economic, social and environmental aspects. Sustainable tourism development is very important to be used as a reference in managing tourism destinations. The large tourism potential in the Bali Province has been inventoried by the Provincial Government of Bali by establishing a tourism area. However, in its development, several designated tourism areas cannot develop optimally and tend to experience a decrease in the quality and quantity of tourist visits. This paper presents transformation pathways toward sustainable tourism development in tourism areas. The general objective is to determine strategies that can be pursued in the development of tourism areas. The specific objective is to develop the best policies and scenarios in the development of tourism areas. This research was conducted in the Soka Tourism Area in Bali Province, Indonesia, which is the only strategic tourism area in Tabanan Regency, which has great potential but has not been able to develop optimally. The data obtained from the focus group discussion, as a data collection method will be analyzed using the MULTIPOL method. The results of the research show that the development of sustainable tourism areas can be carried out by preparing a clear and measurable framework. Promotion, preparation of cross-sector programs and tourism management training activities are needed as priority programs. On the policy, it is necessary to carry out effective planning as an optimal policy involving all stakeholders. In addition, the “Progressive Transformation” and “Integrated Transformation” scenarios can be considered to achieve sustainable tourism development. This study can be an important input for stakeholders in determining policies for the development of tourism areas in the research locations and can be applied in other areas that have similar characteristics.

The paper investigates performance persistence in both Islamic focused (IFFs) and conventional focused fund families (CFFs) in four emerging markets (Saudi Arabia, Malaysia, Indonesia, and Pakistan) from 2007 to 2021 using contingency tables. In the overall sample, we find that positive (negative) persistence in IFFs (CFFs) exists only in the short-run (one-month). At the country level, IFFs demonstrate positive persistence up to one month in Saudi Arabia and Indonesia and six months in Malaysia. For CFFs, negative persistence appears up to one month in Malaysia and six months in Indonesia. Surprisingly, the positive persistence of Indonesian IFFs changes to negative persistence in six months, before disappearing completely later. This result confirms the existence of short-run persistence for both IFFs and CFFs. This study presents new evidence for the persistent performance of fund families in emerging markets.

The 4-bromomethyl-substituted thiazolium salts and corresponding thiazoles obtained through the condensation of 1,3-dibromoacetone with thioamide derivatives were utilised as efficient alkylating reagents for a series of thiophenols and heterylthiols. As a result, a small library of 4-thiomethyl-functionalised 1,3-thiazoles was synthesised in high yields, and their structures were characterised by ¹H, ¹³C NMR, LC-MS and IR spectra. Antioxidant activity of obtained compounds was studied in vitro using the DPPH test. The synthesised compounds showed high absorption level of DPPH radicals in the 70-98% range. For the most active derivatives 7e,m,p,t IC50 values were determined, which were in the range 191-417 µM (for ascorbic acid (reference) IC⁵⁰ value was 29 µM). Obtained radical scavenging activity screening data suggest in-depth study of the antioxidant potential for these types of heterocyclic compounds.