Dioxin sources and industrial emissions control — a review

Dioxin, the collective term for polychlorinated dibenzo‐p‐dioxins and polychlorinated dibenzofurans, are generated during various chemical and high temperature processes. They have been shown to be toxic to humans and animals with 2,3,7,8‐tetrachloro‐dibenzo‐p‐dioxin (TCDD) exhibiting the greatest toxicity. Dioxin has been shown to exhibit immunotoxicity, reproductive and developmental toxicity in several animals. Epidemiological studies on groups of humans with prolonged or elevated exposure to dioxin have indicated increased cancer rates above threshold levels of exposure. Conversely, other studies have concluded that dioxin is a net anticarcinogen. There has been much study aimed at quantifying the relative contributions of the identified dioxin sources to the environmental load. Although some data suggests that burning of vegetation produces measurable amounts of dioxin it is rather industrial process waste streams which emit the greatest amounts. Processes implicated include organic chemical synthesis, metal processing, paper pulp bleaching and incineration of organic materials. Dioxin emission reduction strategies for high temperature processes have focussed upon the minimisation of the conditions at which dioxin forms in exhaust streams. Additionally, screening of process materials has been practised as have substitution of process chemicals in the pulp and paper bleaching industry.     

Cultural and creative clusters – a systematic literature review and a renewed research agenda

ABSTRACT

Cultural/Creative Quarters/Clusters/Districts’ (CCC) have become very popular local development strategies in the last 30 years as reflected within the Urban Planning, Geography, Economics and Cultural Studies literature. However, this multi-disciplinarity has rendered the CCC academic field of research quite fuzzy as authors offers their own definition or borrow from each other without clear explanations. In order to address this issue, this paper presents a systematic literature review and analyses the ways these concepts have evolved, what have been the themes and dimensions associated with them, how they have been studied and researched, and then suggest a renewed research agenda.     

Phosphogypsum: potential uses and problems – a review

Phosphogypsum (PG: CaSO₄·2H₂O) is a waste product generated by the phosphate industry. World production of this waste exceeds 200 million tonnes per year. PG, discharged into the sea, watercourses or in wilderness stocks, contains toxic elements harmful to ecosystems and human health, including heavy metals and radionuclides, and there is therefore a concern regarding environmental impacts. The concentrations of these elements vary between the regions and the processes used, all of which require particular and specific follow-up after the release of PG and during its use. Phosphogypsum is used in agriculture for soil amendment or as fertilizer, as well as in the brick and cement industry, and in road construction.     

India and alternative sources of energy – a review

India should rely on its abundant renewable energy sources to not only facilitate steady and high economic growth but also enable it to meet its commitment to reduce pollution up to 35% less than the 2005 level. On this platform It can expect financial and technological support from the world community.     

Optimization approaches and climates investigations in NZEB—A review

The conception of net zero energy buildings (NZEB) has been introduced to limit energy consumption and pollution emissions in buildings. Classification of NZEB is based on renewable energy (RE) supply options, energy measurement process, RE-sources location, and balances whether are energetic or exergetic. In general, it is traditionally agreed that there are three main steps to reach the NZEB performance, starting through the use of passive strategies, energy efficient technologies, and then RE generation systems. Then, these three steps could be accompanied with the smart integration of advanced efficient energy technologies. A state of the art shows that the main ZEB studies are related to: energy savings, reduce electric bills, energy independence, pollution reduction, and occupants comfort, in addition, others are more interested in the aesthetic aspect by combining modern technologies with innovations to achieve high energy and sustainability performance. Building optimization is a promising technique to evaluate NZEB design choices; it has been adopted to choose the perfect solution to reach the zero energy performance through the optimization of an objective function related to energy (thermal loads, RE generation, energy savings) and/or environment (CO₂ emissions) and/or economy (life-cycle cost (LCC), net-present value (NPV), investment cost). This paper starts by presenting the global energetic and pollution challenges the world faces. Moreover, it shows, to the best to the author’s knowledge, the existing NZEB definitions and the corresponding case studies investigated in 8 different climatic zones (humid continental, humid subtropical, Mediterranean, moderate continental, moderate continental, marine west coast, tropical, semi-arid and hot), the paper also focus on the importance to treat each climate separately. Even in the same country, two or more climates may co-exist. NZEBs drawbacks are also presented. Furthermore, different optimization problems are reviewed in the last section. Building energy optimization methods are employed to obtain the ideal solution for specific objective functions which are either related to energy, and/or environment and/or economy. Optimization variables are distributed between passive and/or RE generation systems. Finally, a table summarizing the most commonly used electric and thermal RE applications which yield to the zero energy balance in each climate, as well as three flowcharts are presented to summarize the whole three-stage procedure, to reach NZEB, starting from building designing, passing through the optimization procedure, and lastly categorizing the zero energy balance.     

Fracture initiation and propagation in intact rock—A review

The initiation and propagation of failure in intact rock are a matter of fundamental importance in rock engineering. At low confining pressures, tensile fracturing initiates in samples at 40%-60% of the uniaxial compressive strength and as loading continues, and these tensile fractures increase in density, ultimately coalescing and leading to strain localization and macro-scale shear failure of the samples. The Griffith theory of brittle failure provides a simplified model and a useful basis for discussion of this process. The Hoek-Brown failure criterion provides an acceptable estimate of the peak strength for shear failure but a cutoff has been added for tensile conditions. However, neither of these criteria adequately explains the progressive coalition of tensile cracks and the final shearing of the specimens at higher confining stresses. Grain-based numerical models, in which the grain size distributions as well as the physical properties of the component grains of the rock are incorporated, have proved to be very useful in studying these more complex fracture processes.     

The ecosystem‐watershed concept in the environmental sciences — a review

The ecosystem‐watershed concept, which originated with the Hubbard Brook Watershed Ecosystem study, provides an important framework for research into contemporary processes in many environments. Integration of freshwater lakes into the basic model allows such studies to be extended back in time, and the typicality of present‐day landscapes and processes to be adjudged. In many ecosystem‐watersheds, inputs, outputs and processes are dominated by cultural factors. Many effects of Man upon environmental systems are thus transmitted and expressed via the material pathways of ecosystem‐watersheds. The ecosystem‐watershed concept is thus uniquely suited to integrative and interdisciplinary analysis of many environmental problems.     

Impact of household plumbing fixtures on drinking water quality — a review

This paper reviews the pertinent literature published since 1970 on the impact of household plumbing systems on drinking water quality through the leaching of metals such as cadmium, copper, iron, lead, tin and zinc into potable water. Copper is found to be more easily and extensively leached than lead. Copper is leached almost exclusively from copper tubing. Lead can be leached from lead pipes, lead‐tin solders and faucets in residences. Zinc and tin require to be monitored as well.     

Modeling occupancy and behavior for better building design and operation—A critical review

People spend more than 90% of their life time in buildings, which makes occupant behavior one of the leading influences of energy consumption in buildings. Occupancy and occupant behavior, which refer to human presence inside buildings and their active interactions with various building system such as lighting, heating, cooling, ventilation, window blinds, and plugs, attract great attention of research with regard to better building design and operation. Due to the stochastic nature of occupant behavior, prior occupancy models vary dramatically in terms of data sampling, spatial and temporal resolution. This paper provides a comprehensive review of the current modeling efforts of occupant behavior, summarizes occupancy models for various applications including building energy performance analysis, building architectural and engineering design, intelligent building operations and building safety design, and presents challenges and areas where future research could be undertaken. In addition, modeling requirement for different applications is analyzed. Furthermore, a few commonly used statistical and data mining models are presented. The purpose of this paper is to provide a modeling reference for future researchers so that a proper method or model can be selected for a specific research purpose.     

Performance and emission characteristics of homogeneous charge compression ignition engine – a review

Homogeneous charge compression ignition (HCCI) engine uses a relatively new mode of combustion technology. In principle, there is no spark plug or injector to assist the combustion process, and the combustion starts at multiple spots once the mixture has reached its auto-ignition temperature. The challenges over the operation of HCCI-mode engines are the difficulties of controlling the auto-ignition of the mixture, operating range, homogeneous charge preparation, cold start, controlling knock and emissions of unburned hydrocarbon (UHC) and carbon monoxide (CO), which needed to be overcome to achieve successful operation of HCCI-mode engine. This paper reviews the working principle of HCCI-mode engine and analyse the knocking in the HCCI combustion. And it also reviews the impact of homogeneous charge on HCCI combustion parameters, such as heat-release rate and maximum pressure. Furthermore, it reviews the performance and emission characteristics of HCCI engine. For each of these parameters, the theories are discussed about successful operation of HCCI engine with comparative evaluation of performance and emission reported in the literature.     

Industrial ecology and sustainable development—a viewpoint

Industrial Ecology (IE) is a novel approach to achieve sustainable development. It aims to optimize the consumption of natural resources and energy and minimize the generation of waste. Industrial Ecology is the study of the means by which humans maintain a desirable carrying capacity given continued economic, cultural and technological evolution. The concept requires that all industrial systems be viewed not in isolation from surrounding system, but in concert with them. Several examples are discussed to illustrate how this can be achieved.     

Environmental health concepts and issues — a viewpoint

The quality of our environment and the effect of environmental agents on our health depend largely on the policies adopted by the international community and governments. Global environmental problems pose a threat to human health and well‐being; but all the world's countries which must act co‐operatively to find measures to address such issues have their particular conceptual and diverse environmental challenges. Several concepts have been developed worldwide to show how environmental issues are increasingly central to our health. This paper addresses some of these concepts as they are relevant to us today and in the future.     

Acidic attack of cement-based materials—a review Part 2. Factors of rate of acidic attack and protective measures

This paper shows that both the aggressivity of an acidic environment and acidic resistance of cement based materials are of a complex nature. Both depend on several conditioning factors. Therefore, the evaluation of the aggressivity of the environment only on the concentration of the aggressive species is entirely unsatisfactory and incorrect. On the other hand, even the evaluation of the acidic resistance on the cement used is inadequate. Therefore, further factors should be taken into consideration, conditions like the action of the aggressive medium on cement based material and the processing factors, e.g. w/c used, curing mode and others, conditioning the resistance of cement based materials. The various possibilies of protecting cement-based materials are considered. These are based on the optimal choice of the composition of the mixture, its consolidation and curing, aimed at ensuring maximal density and minimal permeability of the hardened material. A further possibility represents the application of surface coatings. The most effective way seems to be the preparation of materials on binders of new generation ensuring the compatibility with the acidic environment.     

State of the art in additive manufacturing and its possible chemical and particle hazards—review

Additive manufacturing, enabling rapid prototyping and so-called on-demand production, has become a common method of creating parts or whole devices. On a 3D printer, real objects are produced layer by layer, thus creating extraordinary possibilities as to the number of applications for this type of devices. The opportunities offered by this technique seem to be pushing new boundaries when it comes to both the use of 3D printing in practice and new materials from which the 3D objects can be printed. However, the question arises whether, at the same time, this solution is safe enough to be used without limitations, wherever and by everyone. According to the scientific reports, three-dimensional printing can pose a threat to the user, not only in terms of physical or mechanical hazards, but also through the potential emissions of chemical substances and fine particles. Thus, the presented publication collects information on the additive manufacturing, different techniques, and ways of printing with application of diverse raw materials. It presents an overview of the last 5 years’ publications focusing on 3D printing, especially regarding the potential chemical and particle emission resulting from the use of such printers in both the working environment and private spaces.     

Electric arc explosions—A review

When an electric arc is created, a pressure event occurs. There can be two aspects to this: the shock and sound waves propagated from the expanding arc channel, and the bulk pressurization of the enclosure, if arcing is taking place within a closed volume. The present paper is the first systematic review of the research on both these pressure phenomena. Quantitative studies on electrical arc explosion pressures date back to the 1920s, although arc pressures generated by lightning, which is a type of electric arc discharge, have been studied since the 1700s, but understanding of the phenomena is still not complete or exhaustive. Experimental data are compared to theoretical predictions. It is shown that in an enclosed volume some extremely high pressures can be generated, if the arc current is sufficient. Such pressures can destroy buildings and mechanical equipment and cause injuries or death to nearby individuals. Even without enclosures, the shock waves produced from high energy arcs can cause injuries, although arc flash injury may be of greater concern. Injury potential generally requires that high currents be available, and serious damages or injuries are not associated with low-energy arcing occurrences.     

Environmental regulations and innovation activities — a view point

The impact of environmental regulations on innovative activity is explored in this paper using state‐level and company level data on patents, new product introductions, emissions, and penalties. A significant effect of environmental regulations on corporate innovative activity is found. In addition, excellence in environmental performance appears to have an indirect effect on innovation performance of companies.     

Thermal comfort in transitional spaces—basic concepts: literature review and trial measurement

Current thermal comfort research extensively documents various aspects of the human thermal response to stable environmental conditions. Reviews of recent research on outdoor comfort, however, reveals a lack of information on response to conditions in transitional spaces—those areas that are influenced by outdoor climate, yet are architecturally bounded by a building. In this work, we focused on transitional space as a space in between outdoor and indoor. Transitional spaces were organized into three categories depending on their proximity to interior spaces. Pilot measurements of physical variables were taken in six places. Transitional spaces’ physical environments varied by the space type and architectural characteristics. The typical behaviors observed were walking, standing, and sitting —different and varied compared to the sedentary behavior in offices or homes. The most efficient architectural shape of transitional spaces is related to the corresponding regional climatic condition. It was verified that PMV cannot be used for transitional space thermal comfort predictions because of its unstable and dynamic physical and MET value.     

Norwegian allotment gardens — a study of motives and benefits

Interest in urban allotment gardens (AGs) has increased during recent years. In Oslo, the capital of Norway, one must wait 10–20 years to get a plot in one of the urban AGs. Being an urban gardener can have a number of health benefits. However, the literature in this field has primarily studied community gardens in which it is not possible to stay overnight. An AG in Oslo is a plot of about 200 m² with a small cottage one can live in during the summer season. In the present study, we explore individual plot holders’ reasons for engaging in one of the AGs in Oslo. Thirty-three plot holders were interviewed. The topics discussed concerned their reasons for and the perceived benefits of being plot holders. The findings show that the reasons for engaging in urban gardening are mainly related to a desire for a safe play environment for the children, a place to cultivate, and direct contact with the outdoors. The benefits of having a plot were related to having meaningful activities, being part of a social network and having a respite from ‘normal’ life in one’s apartment. The present findings are unique in that they show that being a plot holder in an AG in Oslo involves much more than having a leisure activity or a place to cultivate. It has health benefits, both physical and psychological. It is a way of living and makes life in the city liveable. In times of densification, it is interesting to discuss the role of the AGs from the gardener’s perspective, but also from a planning perspective.