Speed optimization and bunkering in liner shipping in the presence of uncertain service times and time windows at ports

Recent studies in maritime shipping have concentrated on environmental and economic impacts of ships. In this regard, fuel is considered as one of the important factors for such impacts. In particular, the sailing speed of the vessels affects the fuel consumption directly. In this study, we consider a speed optimization problem in liner shipping, which is characterized by stochastic port times and time windows. The objective is to minimize the total fuel consumption while maintaining the schedule reliability. We develop a dynamic programing model by discretizing the port arrival times to provide approximate solutions. A deterministic model is presented to provide a lower bound on the optimal expected cost of the dynamic model. We also work on the effect of bunker prices on the liner service schedule. We propose a dynamic programing model for bunkering problem. Our numerical study using real data from a European liner shipping company indicates that the speed policy obtained by proposed dynamic model performs significantly better than the ones obtained by benchmark methods. Moreover, our results show that making speed decisions considering the uncertainty of port times will noticeably decrease fuel consumption cost

The relationship between green supply chain management and performance: a meta-analysis of empirical evidences in Asian emerging economics

The purpose of this study is to understand the relationship between green supply chain management (GSCM) practices and firm performance in the manufacturing sector in Asian emerging economies (AEE) based on empirical evidence. Through a systematic literature review, we identified 50 articles that surveyed 11,127 manufacturing companies in the AEE and were published between 1996 and 2015. Subsequently, a conceptual framework was developed and analyzed through a meta-analysis of 130 effects from 25,680 effect sizes. The findings revealed that the GSCM practices lead to better performance in four aspects: economic, environmental, operational, and social performance. Moreover, the results indicate that industry type, firm size, ISO certification, and export orientation moderate several of the GSCM practice-performance relationships. Moreover, the findings of this research help managers and policy makers to have more confidence in the adoption of GSCM practices to improve firm performance. Such results also help researchers to better channel their efforts in studying the GSCM practices in Asian emerging economies. In addition, as meta-analysis has not been widely used in the supply chain management literature, our study is an important step in maturing the academic field by adopting this technique for confirming GSCM practice-performance relationships in the manufacturing sector of Asian emerging economies

Effects of Extremely Low Frequency Electromagnetic Fields and Simultaneous Treatment with Allium Cepa on Biochemical Parameters and Ultrastructure of Ovarian Tissues of Rats

Introduction: This study investigated the effects of extremely low frequency electromagnetic fields (ELF-EMF) (50 Hz, 3 mT) on biochemical parameters of rats’ ovarian tissues and the impact of Allium cepa on the reduction of potential adverse influences of electromagnetic exposure. Material and Methods: In this study 40 female Wistar rats were divided into four groups, including (1) control group (with 3 cc normal saline), (2) ELF-EMF group (exposed to ELF-EMF, 50 Hz), (3) Allium cepa group (received 3 cc Allium cepa), and (4) ELF-EMF and Allium cepa group (exposed to ELF-EMF and simultaneously received Allium cepa daily for 6 weeks. Results: The MDA levels significantly increased in the second group, which were exposed to ELF-EMF and decreased in normal rats that received Allium cepa. Although, SOD, GPx, and CAT activities significantly decreased in ELF-EMF group, the combination treatment with Allium Cepa on exposed rats restored their activities to normal levels. The conduction of transmission electron microscopy study on ELF-EMF group revealed the changes regarding cytoplasmic organelles in the ovarian follicles of exposed rats. Moreover, irregular oocyte with damaged heterochromatic nuclei was observed. In degenerative oocyte, mitochondria lost their cristae Conclusion: The results of the present study suggested that ELF-EMF exposure might cause deleterious effect on ovarian tissues in rats, which may lead to infertility and subfertility. Moreover, using Allium cepa as a nutritional supplement can have beneficial effects in the protection of biological antioxidants and reproductive systems in cases exposed to ELF-EMF

Mg-Al LDH and Calcined LDH: Green Nanocatalysts for wet peroxide oxidation of phenol in wastewater

The catalytic wet peroxide oxidation (CWPO) of phenol from wastewater using Mg-Al LDH and calcined LDH at 500 ºC was investigated. The LDH was synthesized by co-precipitation and characterized by XRD, FTIR, SEM, EDS and BET. XRD result showed that during calcination of LDH at 500 ºC, LDH decomposed to the mixed oxide. The SEM images approved Mg-Al LDH comprised of flakes and the calcined LDH comprised of spherical nanoparticles. BET results indicated the specific surface area of 100.2 and 86.3 m2.g-1 for pure LDH and calcined LDH, respectively. The process was optimized by one factor at a time method and considering four process factors i.e. reaction temperature, peroxide dosage, initial phenol concentration, and reaction time. The optimum conditions resulted at initial phenol concentration of 100 ppm, reaction temperature of 60 ºC, with peroxide volume of 3 mL and time on stream of 45 min over calcined LDH with maximum 85% removal of phenol. On the pure LDH, the maximum phenol removal (79%) resulted at peroxide volume of 2.5 mL at 55 min. The study concluded that the calcined Mg-Al LDH due to synergistic effect of MgO and Mg-Al mixed oxide showed higher catalytic activity despite a relatively low surface area

Sonographic Optic Nerve Sheath Diameter as a Screening Tool for Detection of Elevated Intracranial Pressure

Introduction: Timely diagnosis and treatment of post traumatic, elevated intracranial pressure (EICP), could reduce morbidity and mortality, as well as improve patients’ outcome. This study is trying to evaluate the diagnostic accuracy of sonographic optic nerve sheath diameter (ONSD) in detection of EICP. Methods: Sonographic ONSD of patients with head trauma or cerebrovascular accident suspicious for EICP were evaluated by a trained chief resident of emergency medicine, who was blind to the clinical and brain computed tomography scan (BCT) findings of patients. Immediately after ultrasonography, BCT was performed and reported by an expert radiologist without awareness from other results of the patients. Finally, ultrasonographic and BCT findings regarding EICP were compared. To evaluate the ability of sonographic ONSD in predicting the BCT findings and obtain best cut-off level, receiver operating characteristic (ROC) curve were used. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) of sonographic ONSD in determining of EICP was calculated. P < 0.05 was considered to be statistically significant. Results: There were 222 patients (65.3% male), with mean age of 42.2±19.5 years (range: 16-90 years). BCT showed signs of EICP, in 28 cases (12.6%). The means of the ONSD in the patients with EICP and normal ICP were 5.5 ± 0.56 and 3.93 ± 0.53 mm, respectively (P<0.0001). ROC curve demonstrated that the best cut off was 4.85 mm. Sensitivity, specificity, PPV, NPV, PLR, and NLR of ONSD for prediction of EICP were 96.4%, 95.3%, 72.2%, 98.9%, 20.6, and 0.04, respectively. Conclusion: Sonographic diameter of optic nerve sheath could be considered as an available, accurate, and noninvasive screening tool in determining the elevated intracranial pressure in cases with head trauma or cerebrovascular accident.

Improving demand forecasting in the air cargo handling industry: A case study

Air transportation plays a crucial role in the agile and dynamic environment of contemporary supply chains. This industry is characterized by high air cargo demand uncertainty, making forecasting extremely challenging. An in-depth case-study has been undertaken in order to explore and untangle the factors influencing demand forecasting and consequently to improve the operational performance of an Air Cargo Handling Company. It has been identified that in practice, the demand forecasting process does not provide the necessary level of accuracy, to effectively cope with the high demand uncertainty. This has a negative impact on a whole range of air cargo operations, but especially on the management of the workforce, which is the most expensive resource in the air cargo handling industry. Besides forecast inaccuracy, a range of additional hidden factors that affect operations management have been identified. A number of recommendations have been made to improve demand forecasting and workforce management

Pulmonary manifestations in a cohort of patients with inborn errors of immunity : an 8-year follow-up study

Background: Inborn errors of immunity (IEIs) are a group of congenital diseases caused by genetic defects in the development and function of the immune system. The involvement of the respiratory tract is one of the most common presentations in IEIs. Methods: Overall, 117 patients with diagnosed IEIs were followed-up within 8 years at the National Research Institute of Tuberculosis and Lung Diseases (NRITLD). Demographic, clinical, and laboratory data were collected in a questionnaire. Pulmonary function test (PFT), chest X-ray (CXR), and high-resolution computed tomography (HRCT) scans were obtained where applicable. Results: Our study population consisted of 48 (41%) patients with predominantly antibody deficiencies (PADs), 39 (32%) patients with congenital defects of phagocytes, 14 (11.9%) patients with combined immunodeficiency (CID), and 16 (14%) patients with Mendelian susceptibility to mycobacterial diseases (MSMD).. Recurrent pneumonia was the most common manifestation, while productive cough appeared to be the most common symptom in almost all diseases. PFT showed an obstructive pattern in patients with PAD, a restrictive pattern in patients with CID, and a mixed pattern in patients with CGD. HRCT findings were consistent with bronchiectasis in most PAD patients, whereas consolidation and mediastinal lesions were more common in the other groups. Conclusions: Pulmonary manifestations vary among different groups of IEIs. The screening for lung complications should be performed regularly to reveal respiratory pathologies in early stages and follow-up on already existing abnormalities. (C) 2022 Codon Publications. Published by Codon Publications.Peer reviewe

Search based software engineering: Trends, techniques and applications

© ACM, 2012. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version is available from the link below.In the past five years there has been a dramatic increase in work on Search-Based Software Engineering (SBSE), an approach to Software Engineering (SE) in which Search-Based Optimization (SBO) algorithms are used to address problems in SE. SBSE has been applied to problems throughout the SE lifecycle, from requirements and project planning to maintenance and reengineering. The approach is attractive because it offers a suite of adaptive automated and semiautomated solutions in situations typified by large complex problem spaces with multiple competing and conflicting objectives. This article provides a review and classification of literature on SBSE. The work identifies research trends and relationships between the techniques applied and the applications to which they have been applied and highlights gaps in the literature and avenues for further research.EPSRC and E

The role of Guanxi in green supply chain management in Asia's emerging economies: A conceptual framework

In recent decades, rapid industrial modernization and economic growth have brought substantial environmental problems such as air pollution, hazardous waste, and water pollution for the Asian Emerging Economies (AEE), in particular China, Taiwan, India, Malaysia, Indonesia, Thailand, and South Korea. These countries have started to adopt green supply chain management (GSCM) as a strategy to reduce the environmental impact. There are anecdotal evidences that the adoption of GSCM in this region is partly influenced by Guanxi – a cultural norm, which plays a significant role in relationship governance within supply chain activities among the AEE. Based on a systematic literature review, we develop a conceptual framework that characterizes the drivers and barriers for the adoption of GSCM practices, incorporating Guanxi as a moderator in the manufacturing sector of the AEE. The conceptual framework addresses the roles of two types of Guanxi in the adoption of GSCM: the relational Guanxi at individual level based on social exchange theory and the aggregated Guanxi at firm level derived from social capital theory. This recognition of Guanxi at two separate decision levels help companies better manage their relationships while they green their supply chains. Directions for future research and managerial implications are discussed accordingly