CFD studies of the convective heat transfer coefficients and pressure drops in geometries applied to water cooling channels of the crotch absorbers of ALBA Synchrotron light source

Currently, the storage ring vacuum chambers of ALBA are protected by 156 crotch absorbers made of copper and Glidcop. After more than 10 years of operation as a third-generation light source, the ALBA II project arose, aiming to transform this infrastructure into a fourth-generation synchrotron. This introduces new challenges in terms of the thermal and mechanical design of the future absorbers. The absorbers’ cooling channels consist of a set of 8-mm-diameter holes parallel to each other and drilled in the body of the absorbers. In each hole, there is a 6x1 mm stainless steel concentric inner tube coiled in spiral wires, whose aim is to enhance the heat transfer. The convective heat transfer coefficients used for the original design of the absorbers come from experimental correlations from the literature, and are applied as a global value for the whole system. In this work, Heat Transfer-Computational Fluid Dynamics (HT-CFD) studies of the convective heat transfer coefficients and pressure gradients in three different cooling channel geometries are carried out, aiming at leading the way of designing the cooling systems toward the CFD simulations rather than applying global experimental values. This information will be useful for the sizing of the new absorbers for the ALBA II project

Introductory Chapter: Environmental Risks between Conceptualization and Action

International audienceChanges in the contemporary world materialized in particular through population growth and mobility, urbanization, and economic expansion also result in an increased exposure of people and assets to extreme events and impose, implicitly, adequate management of induced risks. The occurrence of natural and anthropogenic risk phenomena, known as hazards, puts a heavy tribute on disaster-sensitive human communities regardless of their level of development. The magnitude of the disasters and their increasing frequency and severity imply the need for their approach by the entire world community and for global action. Knowledge of risks becomes a sine qua condition in carrying out impact studies, risk prevention plans, spatial planning plans, and, in general, a condition for effective management of natural resources or sustainable development projects

Role of Waste Collection Efficiency in Providing a Cleaner Rural Environment

The exposure of rural communities to illegal waste dumping practices associated with the lack of or poor waste collection schemes prior to the closure of rural dumpsites under EU regulations and the role of collection efficiency afterward in reducing this critical environmental threat constitutes a key issue in rural Romania. The present study reveals huge amounts of household uncollected waste released into the natural environment outside the official statistics of rural dumpsites. Despite the expansion of waste collection coverage towards rural areas since 2010, the problem of illegal dumping practice is difficult to solve. The improvement of collection efficiency, better law enforcement, and surveillance of environmental authorities coupled with educational and environmental awareness are necessary steps to combat this bad practice. A circular economy paradigm must be enacted in rural regions through separate collection schemes and to improve cost-efficient alternatives, such as home composting, and traditional and creative reuse practices, particularly in less developed regions

Backyard burning of household waste in rural areas: environmental impact with focus on air pollution

The paper examines the environmental threats associated with the burning of household waste in open piles across rural communities with a focus on Neamt County (Romania) as a case study of uncontrolled waste disposal practice. This option derived from the lack of efficient municipal waste collection schemes, and on the other hand, it is a traditional disposal route for agricultural wastes besides open dumping on the surroundings. This study estimates the potential amounts of household waste uncollected by formal waste management services to be burnt by rural communities related to regional waste management features and how such bad practice interacts with geographical conditions. The paper performs a quantitative analysis of waste indicators and makes estimations on consequent environmental impact focusing on inventorying air pollutants. The spatial analysis provides an appropriate cartographic representation of the analyzed phenomenon. The conclusions converge towards two main ideas: 1) open burning of mixed household waste could be a significant air pollution source at the local scale, and 2) better rural waste management practices are needed to be implemented in the study area to mitigate environmental and public health threats

Assessment of waste dumping practices in mountain creeks

The paper examines the exposure of mountain creeks towards illegal waste disposal practices related to the lack of waste collection services in rural areas of Romania prior to EU accession and the low waste collection efficiency following the closure of rural wild dumps in 2009-2010. The paper estimates the amounts of household waste uncollected and disposed in selected small Carpathian rivers in the North-East development region. The expansion of built-up areas along the water courses leads to waste dumping practices across mountain villages in the context of poor waste management facilities. Particular morphology of villages and hydrological characteristics of the creeks may influence the magnitude of such bad practices. The paper points out the role of flash floods in cleaning upstream catchments from debris, thus, polluting the downstream rivers and human settlements. An efficient waste collection system in mountain areas has a crucial role to play in mitigating and ultimately preventing the waste dumping practices in water bodies

Les risques urbains – concept en continuelle diversification

Riscurile urbane – concept în continuă diversificare. Oraşul şi riscurile constituie astăzi, mai mult ca oricând, un cuplu de nedespărţit. Concept complex, evolutiv, riscul urban se diversifică în mod continuu, având cauze, dar şi consecinţe, multiple. Cunoaşterea fenomenelor de risc care asaltează în număr din ce în ce mai mare oraşul, rămâne, deseori, aproximativă. Marile catastrofe urbane nu constituie decât vârful unei piramide cu baza extrem de largă dată de mulţimea accidentelor şi dezordinilor cotidiene. Alături de hazardele naturale „clasice”- cutremure de pământ, furtuni, inundaţii ş.a. - vin să se adauge cele de origine antropică - poluarea, incendiile, accidentele din reţelele şi sistemele bazate pe noile tehnologii şi o întreagă gamă, în continuă extindere, de ameninţări şi atingeri la adresa sănătăţii, siguranţei, ordinii publice

Backyard burning of household waste in rural areas: environmental impact with focus on air pollution

The paper examines the environmental threats associated with the burning of household waste in open piles across rural communities with a focus on Neamt County (Romania) as a case study of uncontrolled waste disposal practice. This option derived from the lack of efficient municipal waste collection schemes, and on the other hand, it is a traditional disposal route for agricultural wastes besides open dumping on the surroundings. This study estimates the potential amounts of household waste uncollected by formal waste management services to be burnt by rural communities related to regional waste management features and how such bad practice interacts with geographical conditions. The paper performs a quantitative analysis of waste indicators and makes estimations on consequent environmental impact focusing on inventorying air pollutants. The spatial analysis provides an appropriate cartographic representation of the analyzed phenomenon. The conclusions converge towards two main ideas: 1) open burning of mixed household waste could be a significant air pollution source at the local scale, and 2) better rural waste management practices are needed to be implemented in the study area to mitigate environmental and public health threats

Spatial assessment of construction waste generated by residential buildings in rural areas.

The management of construction waste it is at an early stage in urban areas and lacking in rural areas where this fraction is frequently uncontrolled disposed on public lands. Despite the fact some items of construction waste are considered inert for the environment (soil, concrete) it also contains hazardous items (paint additives, cans, and containers) or recyclables (plastics, metals, wood). Potential recovery of this waste stream is high if it is properly managed. The paper estimates the potential amounts of waste resulted from residential constructions across rural municipalities of Neamț County between 2002 and 2010. These statistical values are calculated at commune level (rural territorial administrative unit) in order to outline the disparities between various geographical areas using thematic cartography. This approach is correlated with demographic features in order to reflect such spatial patterns. The map of population density within built-up areas reveals where the construction sector is emerging at the county scale. Field observations highlight the existence of illegal disposal practices of construction waste in the proximity of settlements or water bodies. This waste stream should receive proper attention in following years in order to achieve recycling and recovery targets imposed by EU regulations