Simultaneous personnel and vehicle shift scheduling in the waste management sector

Urban waste management is becoming an increasingly complex task, absorbing a huge amount of resources, and having a major environmental impact. The design of a waste management system consists in various activities, and one of these is related to the definition of shift schedules for both personnel and vehicles. This activity has a great incidence on the tactical and operational cost for companies. In this paper, we propose an integer programming model to find an optimal solution to the integrated problem. The aim is to determine optimal schedules at minimum cost. Moreover, we design a fast and effective heuristic to face large-size problems. Both approaches are tested on data from a real-world case in Southern Italy and compared to the current practice utilized by the company managing the service, showing that simultaneously solving these problems can lead to significant monetary savings.     

The sense of snow – Individuals’ perception of fatal avalanche events

This empirical paper aims at examining individuals’ risk perception in the context of an environmental disaster. Risk is defined as probability of dying in a snow avalanche. Risk perception is analyzed from two different perspectives: (i) individuals’ estimate of the average avalanche risk and (ii) the perceived personal avalanche risk. The perception of personal risk is summarized in an ordered categorical variable, average risk perception is captured by a measurement previously used in risk communication that results in a continuous variable. The variation in risk perception observed is examined by using individual leisure activities (skiing) and the timing of the survey (fall vs. winter) as proxies for frequency, familiarity, controllability, voluntariness, and beneficiary of risk exposure and by including several individual specific characteristics such as age, gender, education, income. The results show that risk as well as individual specific characteristics are significant determinants of participants’ perception of risk but their relevance differs depending on whether the focus is on perception of average risk or of personal risk.     

Assessment of Ball Milling as a Compounding Technique to Develop Nanocomposites of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) and Bacterial Cellulose Nanowhiskers

The aim of this study was the assessment of high energy ball milling technique to develop poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanocomposites containing bacterial cellulose nanowhiskers (BCNW). Crystallization behaviour of PHBV/BCNW nanocomposites was studied under non-isothermal and isothermal conditions using differential scanning calorimetry. The changes in PHBV crystalline structure were also studied using X-ray diffraction. The results confirmed that BCNW acted as nucleating agents and, hence, favored the crystallization of the PHBV. The oxygen permeability of the nanocomposites was reduced by ~22 % when compared to that of the neat PHBV. This work provides a new insight into the development of polyhydroxyalkanoate composites by means of the high energy ball milling technique.     

Identification of tetramethylarsonium in rice grains with elevated arsenic content

Tetramethylarsonium has for the first time been identified in a commercially grown food product, rice, constituting up to 5.8% of the total arsenic in the rice.     

Improving plant-based genotoxicity bioassay through AFLP technique for trace metal-contaminated water: insights from Myriophyllum aquaticum (Vell.) Verdc. and Cd

Environmental Science and Pollution Research - In this work, we evaluated whether the species Myriophyllum aquaticum (Vell.) Verdc. can be a promising material for devising reliable...