Integration and coordination in after-sales service logistics

Maintenance and after-sales service logistics are important disciplines that have received considerable attention both in practice and in the scientific literature. This attention is related to the often high investments and revenues associated with capital-intensive assets in technically advanced business environments. Different maintenance services such as inspections and preventive maintenance activities are executed with the goal to maximize the availability of these expensive assets. However, unavoidable failures may still happen, which means that, in addition to preventive maintenance and services, repair actions (corrective maintenance) are necessary. Spare parts, service engineers and tools are typically the main resources for executing the repair actions and their availability has a major impact on overall system downtime. In this dissertation, we analyze a multi-resource after-sales service supply chain consisting of a service provider and an emergency supplier. The service provider is contractually responsible for the timely repair of some randomly failing capital intensive assets. To execute a repair, the service provider needs both service engineers and spare parts to replace the malfunctioning parts. In case of spare parts stock out, the service provider can either wait for the regular replenishment of parts or decide to hand over the entire repair call to an emergency supplier. For the latter case, a contract between the service provider and the emergency supplier is necessary to specify the compensation. In the first part of this dissertation, we focus on the optimal integrated planning of spare parts and engineers, considering an asset availability constraint. We evaluate the system performance using Markov chain analysis and queueing models, and employ different optimization algorithms to jointly determine the optimal capacity of the resources. This integrated planning results in considerable cost savings compared to the separate planning of spare parts and engineers. In the second part, we investigate the best contract the supplier can offer to the service provider. Furthermore, we propose different coordinated contracts to achieve optimal revenues for both partners in this after-sales service supply chain, under both full and asymmetric information scenarios. Cooperative games, the dominance of one party over the other (Stackelberg game), and information sharing aspects are the tools included in the second part of this dissertation

Zijm Consortium: Engineering a Sustainable Supply Chain System

In this paper we address one of the current major research areas of the Zijm consortium; engineering sustainable supply chain systems by transforming traditionally linear practices to circular systems. We illustrate this field of research with a case consisting of a network of three firms Willem (W), Hendrik (H), and Maria (M)} and show how the practice of application-oriented state of the art technology transformed their linear relation to the circular Zijm consortium. The work shows that through inspiration and knowledge transfer in the versatile picturesque Twente Region, a group of future generation researchers are shaped

Response of Seed Yield and Essential oil of Black Cumin (Nigella sativa L.) Affected as Foliar Spraying of Nano-fertilizers

In order to investigate the effect of micronutrients foliar application on seed yield and essential oil of black cumin, a field experiment was conducted based on Randomized Complete Block Design (RCBD) with three replications at the farmlocated in Naqadeh city, West Azerbaijan province, Iran, during 2015-2016 growing season. Treatments were separate application of Nano-Iron, Nano-Zinc and Nano-Manganese and double and triple combined treatment of them (Fe+Mn, Fe+Zn, Zn+Mn, Fe+Zn+Mn) and control. Treatments were applied at 2 g/L twice at stem elongation and early flowering stages. Different traits such as plant height, number of follicle per plant, number seed per follicle, 1000- seed weight, biological yield, seed yield, essential oil percentage and yield were measured. The results showed that foliar application of micronutrients had a significant effect on all studied traits and improved yield components and essential oil yield as compared to control. Yield components, seed yield, essential oil percentage and essential oil yield were enhanced by foliar application compared with control. Therefore, combined usage of micronutrients (Nano-Fe+ Nano-Zn+ Nano-Mn) showed the greatest increase in studied traits than their individual usage. The highest seed yield (706.67 kg.ha-1) and essential oil yield (8.66%) were obtained from Fe+Zn+Mn treatment. In general, the results of the present study revealed that the foliar spraying of Nano-micronutrients plays a remarkable role in improving the quantitative and qualitative yield of black cumin as a medicinal plant

Epidemiological and Clinical Aspects of COVID-19; a Narrative Review

There are significant misconceptions and many obstacles in the way of illuminating the epidemiological and clinical aspects of COVID-19 as a new emerging epidemic. In addition, usefulness of some evidence published in the context of the recent epidemic for decision making in clinic as well as public health is questionable. However, misinterpreting or ignoring strong evidence in clinical practice and public health probably results in less effective and somehow more harmful decisions for individuals as well as subgroups in general populations of countries in the initial stages of this epidemic. Accordingly, our narrative review appraised epidemiological and clinical aspects of the disease including genetic diversity of coronavirus genus, mode of transmission, incubation period, infectivity, pathogenicity, virulence, immunogenicity, diagnosis, surveillance, clinical case management and also successful measures for preventing its spread in some communities. Keywords:COVID-19; severe acute respiratory syndrome coronavirus 2; epidemiology; public health; communicable diseases; emergin

Phillips catalysts synthesized over various silica supports: Characterization and their catalytic evaluation in ethylene polymerization

Ethylene polymerization was carried out using Phillips chromium catalyst based on silica supports such as silica aerogel, SiO2 (Grace 643), and titanium modified SiO2 (G 643), and the results were compared with other catalysts based on SiO2 (Aldrich), SBA-15(Hex), SBA-15(Sp) and MCM-41. A combination of TGA, DSC, XRD, nitrogen adsorption, SEM, ICP, FTIR and other analyses were used to characterize the materials. The results showed that the chromium was successfully introduced into silica supports. Shish-kebab polyethylene was prepared via in situ ethylene polymerization with the Cr/SiO2 (G 643) and Cr/Ti/SiO2 (G 643) catalytic systems. A comparison between different types of catalysts revealed that the polymerization activity of Cr/SiO2 (G 643) was significantly increased to 191 kg PE (g Cr)-1 h-1 due to the higher pore volume and pore diameter of Grace silica compared to the other supports. Also, the polymerization activity of the Cr/SiO2 (G 643) catalyst was significantly improved by Ti-modification

Comparing Efficiency of Rice Washing and Soaking Processes in Reducing the Amount of Aflatoxin B1

Contamination of some agricultural products by mycotoxins has exposed the human and animal health to serious concerns. Aflatoxin B1 is the most toxic type of aflatoxins, which is of the highest amount in different foods, including rice, among various types of aflatoxins. The present study was aimed to evaluate the amount of this toxicant in the consuming rice in Yazd city and investigate the effect of rice washing and soaking process on reduction of the mean concentration of aflatoxin B1. The present study was a descriptive-analytical one, in which 36 rice samples (18 domestic types and 18 foreign types of rice) were randomly selected from the rice distribution centers in Yazd city. The Standard No.6872 of the Institute of Standards & Industrial Research of Iran (ISIRI) was used for measuring the amount of aflatoxin B and G toxicants using HPLC (high pressure or performance liquid chromatography) method and purifying by immune affinity column. Analysis of the collected data was performed using SPSS-22 statistical software as well as the statistical methods of one-way ANOVA and Tukey HSD. The mean concentration of aflatoxin B1 in domestic and imported rice was measured equal to 1.461 and 0.508ng/g, respectively. The contamination rate in the imported rice was lower than that in the domestic one, while there was no significant relationship between them (p≥0.166); furthermore, the effect of soaking process on reduction of the toxicant amount in one and ten hours of soaking was statistically insignificant. There was no significant relationship between the effect of a single time of washing and reduction of the amount of toxicant; however, in case of three and five times of washing, the amount of toxicant exhibited a reduction of 68.2% and 98.7%, respectively, which was statistically significant (

Burden of musculoskeletal disorders in the Eastern Mediterranean Region, 1990–2013: findings from the Global Burden of Disease Study 2013

Moradi-Lakeh M, Forouzanfar MH, Vollset SE, et al. Burden of musculoskeletal disorders in the Eastern Mediterranean Region, 1990–2013: findings from the Global Burden of Disease Study 2013. Annals of the Rheumatic Diseases. 2017;76(8):annrheumdis-2016-210146