A novel competitive exact approach to solve assembly line balancing problems based on lexicographic order of vectors.

The assembly line balancing problem (ALBP) is an eminent NP-hard topic that is discussed in mass production systems with low diversity. Primarily, two types of ALBPs are discussed in the literature as type I, which aims to find the minimum number of workstations for a given cycle time, and type II, which assigns some tasks to a given number of workstations such that the maximum workstation load is minimized. To solve ALBPs, various exact, heuristic, and metaheuristic methods have been proposed. However, these methods lose their efficiency when handling large-size problems. Therefore, researchers have focused on proposing heuristic and metaheuristic algorithms to solve large-size problems, especially when they deal with real-life case problems in the industry. This study aims to present a novel and competitive exact method for solving ALBP type II based on the lexicographic order of vectors for feasible solutions. To evaluate the performance of the developed method, a group of highly used standard test problems in the literature is utilized, and the results are compared and discussed in detail. The computational results in this study specify that the developed solution approach performs efficiently and yields the best global solution of all the ALB test problems, which proves the proposed method's potential and its competitive advantage.

A Narrative Review of COVID-19: The New Pandemic Disease.

Nearly every 100 years, humans collectively face a pandemic crisis. After the Spanish flu, now the world is in the grip of coronavirus disease 2019 (COVID-19). First detected in 2019 in the Chinese city of Wuhan, COVID-19 causes severe acute respiratory distress syndrome. Despite the initial evidence indicating a zoonotic origin, the contagion is now known to primarily spread from person to person through respiratory droplets. The precautionary measures recommended by the scientific community to halt the fast transmission of the disease failed to prevent this contagious disease from becoming a pandemic for a whole host of reasons. After an incubation period of about two days to two weeks, a spectrum of clinical manifestations can be seen in individuals afflicted by COVID-19: from an asymptomatic condition that can spread the virus in the environment, to a mild/moderate disease with cold/flu-like symptoms, to deteriorated conditions that need hospitalization and intensive care unit management, and then a fatal respiratory distress syndrome that becomes refractory to oxygenation. Several diagnostic modalities have been advocated and evaluated; however, in some cases, diagnosis is made on the clinical picture in order not to lose time. A consensus on what constitutes special treatment for COVID-19 has yet to emerge. Alongside conservative and supportive care, some potential drugs have been recommended and a considerable number of investigations are ongoing in this regard.

Improvement in osseointegration of tricalcium phosphate-zircon for orthopedic applications: an in vitro and in vivo evaluation.

Similar to metallic implant, using the compact bio-nanocomposite can provide a suitable strength due to its high stiffness and providing sufficient adhesion between bone and orthopedic implant. Therefore, using zirconia-reinforced calcium phosphate composites with new generation of calcium silicate composites was considered in this study. Additionally, investigation of microstructure, apatite formation, and mechanical characteristic of synthetic compact bio-nanocomposite bones was performed. Desired biodegradation, optimal bioactivity, and dissolution of tricalcium phosphate (TCP) were controlled to optimize its mechanical properties. The purpose of this study was to prepare the nanostructured TCP-wollastonite-zirconia (TCP-WS-Zr) using the space holder (SH) technique. The X-ray diffraction technique (XRD) was used to confirm the existence of favorable phases in the composite's structure. Additionally, the effects of calcination temperature on the fuzzy composition, grain size, powder crystallinity, and final coatings were investigated. Furthermore, the Fourier-transform infrared spectroscopy (FTIR) was used for fundamental analysis of the resulting powder. In order to examine the shape and size of powder's particles, particle size analysis was performed. The morphology and microstructure of the sample's surface was studied by scanning electron microscopy (SEM), and to evaluate the dissolution rate, adaptive properties, and the comparison with the properties of single-phase TCP, the samples were immersed in physiological saline solution (0.9% sodium chloride) for 21 days. The results of in vivo evaluation illustrated an increase in the concentration of calcium ion release and proper osseointegration ratio, and the amount of calcium ion release in composite coatings was lower than that in TCP single phase. Nanostructured TCP-WS-Zr coatings reduced the duration of implant fixation next to the hardened tissue, and increased the bone regeneration due to its structure and dimensions of the nanometric phases of the forming phases. Finally, the animal evaluation shows that the novel bio-nanocomposite has increasing trend in healing of defected bone after 1 month.

Knowledge Management Orientation: An Innovative Perspective to Hospital Management.

BACKGROUND: By considering innovation as a new project in hospitals, all the project management's standard steps should be followed in execution. This study investigated the validation of a new set of measures in terms of providing a procedure for knowledge management-oriented innovation that enriches the hospital management system. METHODS: The relation between innovation and all the knowledge management areas, as the main constructs of project management, was illustrated by referring to project management standard steps and previous studies. Through consultations and meetings with a committee of professional project managers, a questionnaire was developed to measure ten knowledge management areas in hospital's innovation process. Additionally, a group of experts from hospital managers were invited to comment on the applicability of the questionnaires by considering if the items are measurable in hospitals practically. RESULTS: A close-ended, Likert-type scale items, consisted of ten sections, were developed based on project management body of knowledge thorough Delphi technique. It enables the managers to evaluate hospitals' situation to be aware whether the organization follows the knowledge management standards in innovation process or not. By pilot study, confirmatory factor analysis and exploratory factor analysis were conducted to ensure the validity and reliability of the measurement items. CONCLUSION: The developed items seem to have a potential to help hospital managers and subsequently delivering new products/services successfully based on the standard procedures in their organization. In all innovation processes, the knowledge management areas and their standard steps help hospital managers by a new tool as questionnaire format.