Making an integrated decision in a three-stage supply chain along with cellular manufacturing under uncertain environments: A queueing-based analysis

Today’s complicated business environment has underscored the importance of integrated decision-making in supply chains. In this paper, a novel mixed-integer nonlinear mathematical model is proposed to integrate cellular manufacturing systems into a three-stage supply chain to deal with customers' changing demands, which has been little explored in the literature. This model determines the types of vehicles to transport raw materials and final parts, the suppliers to procure, the priorities of parts to be processed, and the cell formation to configure work centers. In addition, queueing theory is used to formulate the uncertainties in demands, processing times, and transportation times in the model more realistically. A linearization method is employed to facilitate the tractability of the model. A genetic algorithm is also developed to deal with the NP-hardness of the problem. Numerous instances are used to validate the effectiveness of the modeling and the efficiency of solution procedures. Finally, a sensitivity analysis and a real case study are discussed to provide important management insights and evaluate the applicability of the proposed model.

A Collaborative Experience: Implementation of an Optimised Tc-99m Generator Assembly Process

Technetium-99m (Tc-99m) has a six-hour half-life making customer transportation times a challenge. ANSTO (Australia's Nuclear Science and Technology Organisation) Health Products group has overcome this by delivering the parent isotope Molybdenum-99 (Mo-99), which has a half-life of sixty-six hours, in shielded GENTECH™ generators. As part of ANSTO's questioning attitude, an augmented risk assessment was undertaken to identify any potential exposure risks of the GENTECH™ assembly process. The evaluation identified potential areas of improvement in contamination control for the manual handling of the generator leads. Upon further analysis, contamination events from the generator leads had the potential for skin doses above the threshold for skin tissue reactions. Additional substitution and administrative controls were designed to mitigate the risks identified. The effectiveness of the new controls was assessed for efficiency in the manufacturing process through mock trials and fitness for use in a pharmaceutical cleanroom environment. The implemented controls were monitored, and data from each run was gathered. This data included; changes in radiological conditions and dosimetry results. Upon implementation, there was an observable decrease in glove contamination. The decrease verified that there was a reduction in the risk of skin contamination events. The data analysis was used to model the dose averted, which revealed a reduction in potential extremity dose to production workers. This paper aims to show the optimisation within an approved process through the implementation of engineering and administrative controls, resulting in a dose reduction to workers.

Pre-slaughter road transportation times: meat quality and sensory properties of Nellore bull meat

This study evaluated the effects of different pre-slaughter road transportation times on sensory evaluation and instrumental measurements of Nellore cattle meat quality. Fifteen farms were classified according to transportation times (5 farms per transportation time group) as follows: 1-less than 2 h (< 2), 2-between 2 and 4 h (> 2 and ≤ 4), and 3-between 4 and 6 h (> 4 and ≤ 6). The experiment was a completely randomized design with 15 replications and 3 treatments. Meat analyses were performed on steaks taken from the longissimus dorsi muscle from the 10th rib to the 3rd lumbar vertebra. Road transportation times had no significant effects on pH and mean shear force values. Sarcomere length, myofibrillar fragmentation index, and creatine kinase levels were also not affected by transportation time. Furthermore, road transportation times had no effect on meat tenderness, flavour, odour, and overall acceptability when evaluated by consumers. Thus, a pre-slaughter road transportation time up to 6 h does not affect the sensory evaluation and instrumental measurements of Nellore cattle meat quality when raised using a grazing system.

Chinese Public Attitudes towards, and Knowledge of, Animal Welfare

Food-producing animals make up the majority of animals that humans manage globally, and China has been a major producer and exporter of animal products since the late 1990s. The opinions of the population in China regarding animal welfare are not as well understood as those in Europe. In China, animal welfare as a societal concern is still at an early stage of development. This survey of Chinese attitudes aimed to understand consumer knowledge of and behaviour towards animal welfare, and to determine whether harnessing consumer interests may be a potential future influence on the development of high-welfare agricultural production. Most participants were not aware of the meaning of animal welfare, but the number of those that were aware was higher than reported previously. The welfare of wild animals was rated particularly important compared to other animals. The links between welfare and the taste and/or safety of food were considered to be important, and Chinese consumers reported a willingness to pay more for food from animals produced in good welfare conditions, although the quality of the food was considered more important than the animal suffering. A large majority of the respondents reported that there should be legislation protecting animals and certification of welfare on farms, that animals on farms should be provided with enjoyable experiences and that transportation times should be minimised. Furthermore, most respondents reported that animals should be stunned before slaughter. We conclude that animal welfare is of importance to the Chinese consumer, in particular because of its connection to food quality.

Stress Associated with Simulated Transport, Changes Serum Biochemistry, Postmortem Muscle Metabolism, and Meat Quality of Broilers

Many factors contribute to the stress of transporting broilers from the farm to the processing plant. Using a motion simulation machine, a total of 144 male broilers were employed to determine the effect of motion, vibration, and feed withdrawal during transportation on serum biochemical parameters, postmortem muscle metabolism, and meat quality of broilers. The results indicated that transportation did not affect the activity of lactate dehydrogenase, γ-glutamyl transferase, aspartate aminotransferase, creatine kinase, and glucose in the serum, glutathione peroxidase in the breast and thigh muscle, nitric oxide synthase (NOS) in the breast, and heat stress protein 70 mRNA expression level in the liver (p > 0.05). Serum triiodothyronine, thyroxine, and insulin concentration declined with 2 h transportation (p < 0.05) and recovered with 4 h transportation (p < 0.05). NOS concentration in the thigh increased with 2 h transportation (p < 0.05) and recovered with 4 h transportation (p < 0.05). Two-hour and 4 h transportation increased the activity of superoxide dismutase in both muscles. Malondialdehyde, lactic acid, and drip loss24 h in both thigh and breast muscles increased, and glycogen in both muscles decreased with increasing transportation times (p < 0.05). Two-hour transportation did not influence pH45 min and pH24 h in the breast and thigh muscle, but these indexes decreased with 4 h transportation. This experiment supports and extends previous work that identified transportation as a major risk in relation to bird welfare and meat quality.

An improved memetic algorithm for the flexible job shop scheduling problem with transportation times

In the practical production, the transportation of jobs is existed between different machines. These transportation operations directly affect the production cycle and the production efficiency. In this study, an improved memetic algorithm is proposed to solve the flexible job shop scheduling problem with transportation times, and the optimization objective is minimizing the makespan. In the improved memetic algorithm, an effective simulated annealing algorithm is adopted in the local search process, which combines the elite library and mutation operation. All the feasible solutions are divided into general solutions and local optimal solutions according to the elite library. The general solutions are executed by the simulated annealing algorithm to improve the quality, and the local optimal solutions are executed by the mutation operation to increase the diversity of the solution set. Comparison experiments with the improved genetic algorithm show that the improved memetic algorithm has better search performance and stability.

Two-level simulation approach to evaluate the performance of autonomous wheelchairs in a hospital

In this paper, we present the combined usage of two different simulation levels to evaluate the economic and quality-of-service impact of deploying a fleet of autonomous wheelchairs in a hospital. The first simulation level deals with the physical world and takes into account the characteristics of a real robot, such as dimensions, sensor configuration, and speed. We simulate different trajectories in order to obtain realistic transportation times that are subsequently used in the high-level simulation. This high-level simulation considers those hospital resources that are affected by the inclusion of automated wheelchairs, and computes the economic implications of partially or totally substituting the current fleet of manual wheelchairs. Our results show that switching to automated wheelchairs may be beneficial in terms not only of reduced waiting times for patients, but also of economic savings.

Survival of the copepod Mesocyclops longisetus during simulations of transport from hatchery to target areas for biological control of mosquito larvae

Copepods have been successfully used in many countries for the biological control of larvae of mosquitoes that vector diseases. In Brazil, this line of research has been focused on the use of the copepod Mesocyclops longisetus (Thiébaud, 1914) for the biological control of the mosquito Aedes aegypti (Linnaeus, 1792). The transportation of the copepods from the place where they are reared to where they will be used often involves long distances for extended periods of time. This study assesses the survivorship of M. longisetus during simulation of transport under different conditions. Different loading densities (20, 30, 40, 80, and 120 ind.L) and stirring times (30 minutes, one hour, two hours, and four hours) were tested. Survivorship was high, with 75% of the results equal or higher than 90% survival. Reduced mortality was observed when transportation time was up to 120 minutes and densities were up to 40 ind.L. In higher densities or longer transportation times, the mortality rate was significantly affected.