554 research outputs found
Biofuel as an alternative shipping fuel : technological, environmental and economic assessment
© Royal Society of Chemistry 2019Fossil derived fuels available for application within the maritime sector have been dominated by heavy fuel oil (HFO), which is conventionally used in low speed (main) engines, and more refined fuels such as marine diesel oil (MDO), which is consumed in fast or medium speed engines. However, increasing fuel costs and regulatory pressure such as the restrictions placed on sulphur content have increased interest in the use of alternative fuels. A number of alternative fuels have been identified and may be viable for use within the maritime sector including straight vegetable oil (SVO) as an alternative to HFO in low speed engines, biodiesel to replace MDO/MGO in low to medium speed engines and bio-liquefied natural gas (bio-LNG) in gas engines using LNG. The potential sources of biomass feedstocks, conversion pathways and technologies are identified. The key parameters limiting their potential application are examined, in particular, availability, technological development, technical integration, and operational consequences. A proposed solution to overcome these limitations is recommended. The effective implementation of these strategies will enable the more widespread use of biofuels in marine applications, significantly reducing emissions from ships and improving global air quality and also protecting the ecological environment.Peer reviewe
The dynamic impact among oil dependence volatility, the quality of political institutions, and government spending
Ablation of Oil-Sand Lumps in Hydrotransport Pipelines
Oil-sand ore is a kind of heavy crude oil found primarily in Canada. The surface mining of this petroleum resource requires expensive 400-ton capacity trucks to transport the ore to the slurry plant. The slurry prepared with the crushed ore is usually conditioned in a hydrotransport pipeline prior to extracting bitumen. As the elimination of the mammoth trucks has a tremendous economic and environmental incentive, it is of industrial interest to employ new processes capable of conditioning oil-sand right at the mine face. This would demand an accelerated rate of conditioning compared to what is achieved at present in the industry. One of the significant steps of the conditioning process is oil-sand lump ablation (OSLA). An understanding of the fundamental concepts associated with OSLA is essential to achieve any industrial-scale change in the current conditioning method. A number of parameters such as temperature, lump size, pipe diameter, pipe length, flow rate, and shear influence the ablation process. The current chapter introduces the concept of OSLA. It also includes a comprehensive review of the most important models available to predict the ablation rate and the scope of future works
Assessment of Karstification Degree in the Copacabana Group for a Tailings Dam Foundation, South Andes, Peru
The world-wide occurrence of carbonate rocks is extensive, and Peru is no exception. Many mining facilities are located in or on carbonate rocks. Under specific conditions, carbonate rocks show varying degrees of karstification, which represent a potential high risk of damage or failure to mine facilities, especially tailings and water impoundments due to subsidence or internal erosion problems. Adequate engineering measures, including proper characterization of the foundation materials, should be taken to characterize foundation materials and mitigate the risk. This paper presents the assessment of the potential of karst dissolution in the Copacabana Group underlying about 50% the foundation of a proposed tailings dam and storage facility, located in the South Andes of Peru. A thorough geotechnical site investigation program was carried out in the area, which included regional and local geological mapping, geotechnical drilling, test pits, permeability tests, effervescence test in cores, petrographic analyses, and X-Ray diffraction tests. Hydrogeological studies, such as pumping and tracer tests, were also performed by other consultants to verify the observations, conclusions, and opinions developed from the geotechnical investigation program. The results of the geotechnical investigation allowed proper characterization of the dam foundation and the tailings storage facility and estimation of the degree of karstification in the carbonate rocks of the Copacabana Group. The completed geological site characterization was then used to locate the tailings dam and impoundment area to avoid areas of pervasive karst and to implement defensive engineering measures, including grout curtains and slush grouting of smaller cavities and joints, among others
Wireless-Powered Communication Assisted by Two-Way Relay with Interference Alignment Underlaying Cognitive Radio Network
This study investigates the outage performance of an under-laying
wireless-powered secondary system that reuses the primary users (PU) spectrum
in a multiple-input multiple-output (MIMO) cognitive radio (CR) network. Each
secondary user (SU) harvests energy and receives information simultaneously by
applying power splitting (PS) protocol. The communication between SUs is aided
by a two-way (TW) decode and forward (DF) relay. We formulate a problem to
design the PS ratios at SUs, the power control factor at the secondary relay,
and beamforming matrices at all nodes to minimize the secondary network's
outage probability. To address this problem, we propose a two-step solution.
The first step establishes closedform expressions for the PS ratios at each SU
and secondary relay's power control factor. Furthermore, in the second step,
interference alignment (IA) is used to design proper precoding and decoding
matrices for managing the interference between secondary and primary networks.
We choose IA matrices based on the minimum mean square error (MMSE) iterative
algorithm. The simulation results demonstrate a significant decrease in the
outage probability for the proposed scheme compared to the benchmark schemes,
with an average reduction of more than two orders of magnitude achieved
The Role of the Iranian Library and Information Science Association in the Informal Education of Librarians
This article reports on a survey of librarians on their view of the role of the Iranian Library and Information Science Association in informal education of librarians. The survey uses a descriptive-analytical approach with categorized sampling of two groups of members in Tehran and Khorasan. The results show that the association is successful in holding informal training programs for librarians. The T test indicates no significant difference between librarians in Tehran and in Khorasan except in two factors. The difference is shown in positive effect on job evaluation, and suitability of scheduled dates, date of monthly seminars, and level of education. The F test shows no significant difference between member categories except in three factors. The difference is in the suitability of subjects, the number of librarians attending, and the factor of history of the association
Sequence homology: A poor predictive value for profilins cross-reactivity
BACKGROUND: Profilins are highly cross-reactive allergens which bind IgE antibodies of almost 20% of plant-allergic patients. This study is aimed at investigating cross-reactivity of melon profilin with other plant profilins and the role of the linear and conformational epitopes in human IgE cross-reactivity. METHODS: Seventeen patients with melon allergy were selected based on clinical history and a positive skin prick test to melon extract. Melon profilin has been cloned and expressed in E. coli. The IgE binding and cross-reactivity of the recombinant profilin were measured by ELISA and inhibition ELISA. The amino acid sequence of melon profilin was compared with other profilin sequences. A combination of chemical cleavage and immunoblotting techniques were used to define the role of conformational and linear epitopes in IgE binding. Comparative modeling was used to construct three-dimensional models of profilins and to assess theoretical impact of amino acid differences on conformational structure. RESULTS: Profilin was identified as a major IgE-binding component of melon. Alignment of amino acid sequences of melon profilin with other profilins showed the most identity with watermelon profilin. This melon profilin showed substantial cross-reactivity with the tomato, peach, grape and Cynodon dactylon (Bermuda grass) pollen profilins. Cantaloupe, watermelon, banana and Poa pratensis (Kentucky blue grass) displayed no notable inhibition. Our experiments also indicated human IgE only react with complete melon profilin. Immunoblotting analysis with rabbit polyclonal antibody shows the reaction of the antibody to the fragmented and complete melon profilin. Although, the well-known linear epitope of profilins were identical in melon and watermelon, comparison of three-dimensional models of watermelon and melon profilins indicated amino acid differences influence the electric potential and accessibility of the solvent-accessible surface of profilins that may markedly affect conformational epitopes. CONCLUSION: Human IgE reactivity to melon profilin strongly depends on the highly conserved conformational structure, rather than a high degree of amino acid sequence identity or even linear epitopes identity
Cyanobacteria in Surface and Bank Filtered Drinking Water Sources: Application of Phycocyanin Probes for Monitoring Blooms
RÉSUMÉ Les cyanobactéries sont une préoccupation pour les sources d'eau potable étant donné les impacts anticipés des changements climatiques et de l'eutrophisation des plans d'eau. L'objectif principal de ce projet de Maitrise était de proposer un système rapide, à faible coût pour le suivi des cyanobactéries dans les sources d'eau potable. Plus précisément, l'objectif était d'évaluer la précision des sondes à phycocyanine (PC) pour le suivi des cyanobactéries en continu. Pour valider la sonde de PC pour mesurer les concentrations des cyanobactéries et l'abondance du phytoplancton, les résultats de sonde ont été comparés à des comptes cellulaires taxonomiques provenant d'échantillons choisis de l'eau brute.----------ABSTRACT Cyanobacteria are a growing concern in drinking water sources given rising temperatures from global climate change and increasing eutrophication of water bodies. The main goal of this project was to propose a rapid, low cost monitoring system by applying an in situ phycocyanin in drinking source waters. More specifically, the objective was to evaluate the accuracy of phycocyanin (PC) probes for monitoring cyanobacteria in source waters. Continuous monitoring was conducted using an online fluorescence probe to measure phycocyanin. To validate the PC probe for cyanobacteria and phytoplankton abundance results were compared to traditional taxonomic cell counts from raw water grab samples
Inferential measurement and control of ballast water treatment system
As a result of interaction with the surrounding environment, shipping has become one of the vectors of bio-invasion across the globe. Ballast water is one of the means of bio-invasion from shipping through which microorganisms break through natural barriers and establish in a new location. Shipboard treatment systems are predominately considered as mitigating measures for bio-invasion via a ballast water system. Currently shipboard performance monitoring of ballast water treatment systems, and thus assessment of discharge quality of ballast water as required by the Convention, depends on off-line laboratory assays with long delay analysis. Lack of online measurement sensors to assess the viability of microorganisms after treatment has made monitoring and thus control of ballast water treatment systems difficult. In this study, a methodology was developed, through a mathematical algorithm, to provide an inferential model-based measurement system in order to monitor and thus control non-observable ballast water systems. In the developed inferential measurement the primary output of the treatment system is inferred by using easy to measure secondary output variables and a model relating these two outputs. Data-driven modeling techniques, including Artificial Neural Networks (ANN), were used to develop an estimator for the small scale UV treatment system based on the data obtained from conducted experiments. The results from ANN showed more accuracy in term of Root Mean Squared Error (RMSE) and Linear Correlation Coefficient (LCC) when compared to the other techniques. The same methodology was implemented to a larger scale treatment system comprising micro-filter and UV reactor. A software-based inferential measurement for online monitoring of the treatment system was then developed. Following monitoring, inferential control of the treatment setup was also accomplished using direct inverse control strategy. A software-based “Decision Making Tool” consisted of two intelligent inverse models, which were used to control treatment flow rate and maintain the effective average UV dose. The results from this study showed that software-based estimation of treatment technologies can provide online measurement and control for ballast water system.EThOS - Electronic Theses Online ServiceEuropean funded project “BaWaPla”GBUnited Kingdo
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