972 resultados para waste oil
Resumo:
Following the collapse of the Soviet Union in 1991, the newly independent oil-rich country of Kazakhstan has become a major recipient of foreign direct investment (FDI). Although international organisations such as the IMF and UNCTAD have claimed that FDI could be considered an engine in the transition from state socialism and as a powerful force for integration of this region into the global economy; this investment also poses significant risks to Kazakhstan. These risks fall into two broad categories: The first category can be broadly described as issues associated with the “resource curse” or the “Dutch Disease”. The term Dutch Disease describes a situation where booming demand in oil exporting countries, due to high oil revenues, leads to shift of an economy’s productive resources from the tradeable sector to the non-tradeable sector. The second category is associated with the over-dependency of oil exporting countries on a relatively small number of large multinational corporations (MNCs). This over-dependency can lead to a situation where licenses and concessions are granted at less favourable conditions than if they were auctioned in an efficient market. Examining the licensing policy of the Kazakhstani Energy and Mineral Resource Ministry, this paper notes that the latter issue of over-dependency has become less of a risk due to deliberate efforts to diversify investment relationships. Notwithstanding this situation there is some evidence that it remains difficult for oil exporting nations such as Kazakhstan to ensure that oil revenues are channelled into sustainable economic development.
Resumo:
There have been considerable developments in Merseyside over the last fifteen years with regards to the commercialisation of recycled demolition aggregate. Liverpool is an urban region that at the time was undergoing regeneration. This required the demolition of old infrastructure. Subsequent reconstruction required new construction materials. A project started in 2001 to investigate the economics, practicalities and technicalities of using recycled demolition aggregates in concrete precast products. It was estimated that if all six demolition contractors around Liverpool worked round the clock (i.e. assuming there was enough feed material) they would still have found it difficult to maintain the required supplies for a single precast factory. Investment in equipment was therefore required to guarantee supply and improve the quality of the recycled demolition aggregate. The market forces and the incentives/drivers for construction companies to adopt sustainable practises have encouraged investment of several million pounds to be made in new recycling plants and has resulted in ‘urban quarries’. This paper describes the developments in recycling of construction and demolition waste over the last decade in Merseyside and shows that recycling is not only sustainable but also profitable.
Resumo:
Worldwide, the building sector requires the production of 4 billion tonnes of cement annually, consuming more than 40% of global energy. Alkali activated “cementless” binders have recently emerged as a novel eco-friendly construction material with a promising potential to replace ordinary Portland cement. These binders consist of a class of inorganic polymer formed mainly by the reaction between an alkaline solution and an aluminosilicate source. Precursor materials for this reaction can be found in secondary material streams from different industrial sectors, from energy to agro-alimentary. However, the suitability of these materials in developing the polymerisation reaction must be assessed through a detailed chemical and physical characterisation, ensuring the availability of required chemical species in the appropriate quantity and physical state. Furthermore, the binder composition needs to be defined in terms of proper alkali activation dosages, water content in the mix, and curing conditions. The mix design must satisfy mechanical requirements and compliance to desired engineering properties (workability, setting time) for ensuring the suitability of the binder in replacing Portland cement in concrete applications. This paper offers a structured approach for the development of secondary material-based binders, from their identification to mix design and production procedure development. Essential features of precursor material can be determined through chemical and physical characterisation methods and advanced microscope techniques. Important mixing parameters and binder properties requirements are examined and some examples of developed binders are reported.
Resumo:
One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of 90Sr insertion and decay in C-S-H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold this radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that 90Sr is stable when it substitutes the Ca2+ ions in C-S-H, and so is its daughter nucleus 90Y after β-decay. Interestingly, 90Zr, daughter of 90Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Therefore, cement appears as a suitable waste form for 90Sr storage.
Resumo:
We evaluated the effectiveness of diode laser trans-scleral cyclophotocoagulation (TSCPC) on intraocular pressure (IOP) in nine patients having raised IOP following use of silicone oil (SO) for retinal detachment (RD) surgery in a retrospective observational case series. Diode laser TSCPC was applied at a power setting of 1.75 to 2.5 watts, for two sec with a maximum of 30 applications. The patients were followed up for 40 to 312 weeks. The mean pre-laser IOP was 32.06 mm Hg (SD 7.32). The mean post-laser IOP at one month, three months and six months was 17.89 mm Hg (SD 8.23), 21.89 mm Hg (SD 8.16) and 21.67 mm Hg (SD 7.55) respectively. The final IOP (at the last follow-up) was 19.56 mm Hg (SD 7.85) (P=0.021). Seven of them had undergone SO removal. In our observation, effectiveness of TSCPC in long-term control of SO-induced ocular hypertension was limited as compared to short-term control of IOP.
Resumo:
Globalisation has led to a shift in world order with the rise of the corporate non-state actor. This rise has led to an assumption that Multi-National Corporations (MNCs) must assume responsibilities beyond profit maximisation for shareholders. With the rise of the MNC as a corporate non-state actor there have been discussions around the role of business with regard to human rights.
This article looks at the case of oil extraction in Nigeria. Focussing on the historical dependency of Nigeria and the evolution of the state into a resource-dependent country, it looks at the limitations of existing human rights obligations as they relate to business. This article proposes that corporate social responsibility (CSR) policies of MNCs can act as a preliminary stage in the quest for wider human rights protections. It is in motivating MNCs to design and implement effective CSR policies in dependent states like Nigeria, that the challenge lies.
Modelling of Evaporator in Waste Heat Recovery System using Finite Volume Method and Fuzzy Technique
Resumo:
The evaporator is an important component in the Organic Rankine Cycle (ORC)-based Waste Heat Recovery (WHR) system since the effective heat transfer of this device reflects on the efficiency of the system. When the WHR system operates under supercritical conditions, the heat transfer mechanism in the evaporator is unpredictable due to the change of thermo-physical properties of the fluid with temperature. Although the conventional finite volume model can successfully capture those changes in the evaporator of the WHR process, the computation time for this method is high. To reduce the computation time, this paper develops a new fuzzy based evaporator model and compares its performance with the finite volume method. The results show that the fuzzy technique can be applied to predict the output of the supercritical evaporator in the waste heat recovery system and can significantly reduce the required computation time. The proposed model, therefore, has the potential to be used in real time control applications.