1,128 research outputs found
A hydromechanically-based risk framework for CO b2 s storage coupled to underground coal gasification
PhD ThesisMost of the energy produced in the world comes from fossil fuels: coal, oil and
gas. Amongst them, coal is the most abundant and widespread fossil fuel in the
world. Underground Coal Gasi cation (UCG), an in situ method to extract the
calori c value of the coal, has been known for a century but has had very limited
implementation throughout the world, mainly due to the availability of cheap oil
over that period. It is now gaining relevance in order to unlock vast resources of coal
currently not exploitable by conventional mining.
However, growing concern on increased levels of carbon dioxide concentration in
the atmosphere is pointing out the necessity to reduce the use of fossil fuels. Since
alternative sources of energy (e.g. nuclear and renewables) are not in a position
to meet the constantly increasing demand in a short term, carbon capture and its
geological sequestration (CCS) is considered the best remedial option.
An environmental risk assessment framework has been developed for coupling
UCG to CCS accounting for bene ts and cost from both global and local perspectives.
A UCG site presents signi cant di erences from other typical CCS projected
scenarios, most notably the injection of CO2 into a heavily fractured zone. A model
which accounts for
ow in fractures represented by dual-porosity
ow (TOUGH2) is
coupled to a geomechanical model (FLAC3D). The impact of this fractured zone in
the CO2 injection pressure buildup and stress eld is evaluated. Furthermore the effect
of stress-dependent fracture permeability is assessed with the hydro-mechanically
i
coupled compositional simulator GEM. Simulation results suggest that in such a scenario,
CO2 injectivity and dissolution improve though con nement is compromised
and commercial injection rates seem unattainable. The e ects of miscibility and
relative permeability on pressure buildup implemented in semianalytical solutions
are also evaluated. Albeit further research is required, a UCG operation may, therefore,
not be able to accommodate the produced CO2 in the gasi ed cavity and its
surroundings in a safe and economical fashion. Rigorous studies and management
practices are needed to establish the requirements for secure long-term con nement
of the carbon dioxide in such scenario.HSBC & UK Engineering and Physical Sciences Research
Council (EPSRC) under the program EP/F013337/1. The Royal Academy of Engineering
supported my trip to Lawrence Berkeley National Laboratory with a travel
grant (ref. 09-376). Further funding was made available for extending the research by
the UK Strategy Board (STB) through the UK Transfer Partnership (KTP) scheme,
with the participation of Durham University and ERC Equipoise Ltd
Five decades of cuprizone, an updated model to replicate demyelinating diseases
Abstract: Introduction: Demyelinating diseases of the central nervous system (CNS) comprise a group of neurological disorders characterized by progressive (and eventually irreversible) loss of oligodendrocytes and myelin sheaths in the white matter tracts. Some of myelin disorders include: Multiple sclerosis, Guillain-Barré syndrome, peripheral nerve polyneuropathy and others. To date, the etiology of these disorders is not well known and no effective treatments are currently available against them. Therefore, further research is needed to gain a better understand and treat these patients. To accomplish this goal, it is necessary to have appropriate animal models that closely resemble the pathophysiology and clinical signs of these diseases. Herein, we describe the model of toxic demyelination induced by cuprizone (CPZ), a copper chelator that reduces the cytochrome and monoamine oxidase activity into the brain, produces mitochondrial stress and triggers the local immune response. These biochemical and cellular responses ultimately result in selective loss of oligodendrocytes and microglia accumulation, which conveys to extensive areas of demyelination and gliosis in corpus callosum, superior cerebellar peduncles and cerebral cortex. Remarkably, some aspects of the histological pattern induced by CPZ are similar to those found in multiple sclerosis. CPZ exposure provokes behavioral changes, impairs motor skills and affects mood as that observed in several demyelinating diseases. Upon CPZ removal, the pathological and histological changes gradually revert. Therefore, some authors have postulated that the CPZ model allows to partially mimic the disease relapses observed in some demyelinating diseases. Conclusion: for five decades, the model of CPZ-induced demyelination is a good experimental approach to study demyelinating diseases that has maintained its validity, and is a suitable pharmacological model for reproducing some key features of demyelinating diseases, including multiple sclerosis.UAEME
Criterios de implementación ISO 14000:2015 Caso estudio empresa de servicios públicos SERVIGUAVIO.
Criterios de implementación ISO 14000:2015 Caso estudio empresa de servicios públicos SERVIGUAVIO.En Colombia se produce una gran cantidad de residuos sólidos, de los cuales a tan solo una pequeña parte se les un tratamiento o disposición final adecuada. El manejo inadecuado de dichos residuos, es una de las principales fuentes de contaminación ambiental en el país.
las empresas prestadoras de aseo están en la obligación de recolectar los residuos sólidos y darles una disposición final adecuada. En nuestro caso vamos a hablar de SERVIGUAVIO, empresa prestadora de servicios de aseo en el municipio de Gacheta, organización a la cual se le realizo visita y se verifico el grado de cumplimiento, bajo los criterios de la ISO 14001:2015.
Si bien hay falencias en el cumplimiento de la norma (ISO 14001:2015), se pude evidenciar el interés por parte de las directivas para mejorar el sistema de gestión.In Colombia, a large amount of solid waste is produced, of which only a small part is treated or disposed of properly. The inadequate management of such waste is one of the main sources of environmental pollution in the country.
the cleaning companies are obliged to collect solid waste and give them an adequate final disposal. In our case we are going to talk about SERVIGUAVIO, a company that provides cleaning services in the municipality of Gacheta, an organization that visited it and verified the degree of compliance, under the criteria of ISO 14001: 2015.
Although there are shortcomings in complying with the standard (ISO 14001: 2015), the interest on the part of the directives to improve the management system could be evidenced
A-DInSAR Monitoring of Landslide and Subsidence Activity: A Case of Urban Damage in Arcos de la Frontera, Spain
Terrain surface displacements at a site can be induced by more than one geological process. In this work, we use advanced differential interferometry SAR (A-DInSAR) to measure ground deformation in Arcos de la Frontera (SW Spain), where severe damages related to landslide activity and subsidence have occurred in recent years. The damages are concentrated in two residential neighborhoods constructed between 2001 and 2006. One of the neighborhoods, called La Verbena, is located at the head of an active retrogressive landslide that has an extension of around 0.17 × 106 m2 and developed in weathered clayey soils. Landslide motion has caused building deterioration since they were constructed. After a heavy rainfall period in winter 2009–2010, the movement was accelerated, worsening the situation. The other neighborhood, Pueblos Blancos, was built over a poorly compacted artificial filling undergoing a spatially variable consolidation process which has also led to severe damage to buildings. For both cases, a short set of C-band data from the “ENVISAT 2010+” project has been used to monitor surface displacement for the period spanning April 2011–January 2012. In this work we characterize the mechanism of both ground deformation processes using in situ and remote sensing techniques along with a detailed geological interpretation and urban damage distribution
Comparativa entre factores de dispersión obtenidos con varios detectores en un acelerador lineal con colimadores cónicos usado para tratamientos con radiocirugía
Los factores de dispersión total (St) son requeridos para el cálculo de dosis en tratamientos de radiocirugía con acelerador lineal. Es bien sabido que la dosimetría de éstos presenta complicaciones asociadas a las pequeñas dimensiones de los haces de radiación empleados. Por ello, varios autores1,2 han comparado mediciones de los St con diversos detectores encontrando considerables diferencias entre algunos de ellos. En este trabajo se compararon los St medidos con siete diferentes detectores en un acelerador lineal convencional con colimadores cónicos
Alternative system to measure hydrogen content in molten aluminium using an electrochemical sensor
1037-1042The most reliable techniques for the direct measurement of hydrogen content in liquid aluminium are based on Sievert’s law or use electrochemical probes introduced directly in liquid aluminium. The main drawback of these methods is the high cost of the equipment. An alternative apparatus has been developed and tested. This equipment combines a widely used and much cheaper hydrogen electrochemical sensor with the procedure already patented and commonly used by gas recirculation techniques. The device has been constructed and calibrated using gaseous mixtures of known hydrogen content. For validation, the results obtained with this apparatus have been compared with hydrogen content measurements in liquid aluminium using the commercial Alscan equipment in an industrial facility. Experimental results suggest that the apparatus proposed in this work is capable of detecting hydrogen content in liquid aluminium obtaining measurements that are in a good agreement with those obtained using the commercial Alscan equipment. On the other hand, results also suggest that it is important to take into account the operating atmospheric pressure to correct the readings obtained from Alscan when operating at atmospheric pressure levels far from 1 atm
Major trends in the development of ankle rehabilitation devices
In this paper we review the ankle rehabilitation devices, both those that are already commercially available and those which are in the stage of development in laboratories and research centers. Also, a rehabilitation device is proposed here including reporting results of clinical trials prior to its availability at a commercial level. At the end of the paper there is a mention about the possibility of developing a rehabilitation ankle machine with some particular features
Cirugía derivativa más radioterapia intraoperatoria y externa en el carcinoma de páncreas localizado e irresecable
Presentamos una serie de 25 casos de carcinomas de páncreas localmente avanzados e irresecables, sin metástasis a distancia, tratados con cirugía derivativa, radioterapia intraoperatoria e irradiación externa: 18 tumores de cabeza (16 con ictericia obstructiva) y 7 de cuerpo. Se realizó derivación biliar en 18 y gastroyeyunostomía en 19. La mortalidad operatoria fue nula, con una morbilidad del 16%. A largo plazo se produjeron 3 hemorragias digestivas, 2 ictericias obstructivas, una colangitis y una obstrucción intestinal. Se obtuvo un 72% de control local de la enfermedad y todos los fallecidos por progresión tumoral desarrollaron metástasis hepáticas y/o peritoneales. Presentaban dolor pancreático 22 pacientes y 20 experimentaron remisión del mismo en una a 2 semanas. La analgesia fue definitiva en 12 y reapareció el dolor tardíamente en ocho. La supervivencia media fue de 9 meses (rango 4-24). La revisión de la literatura pone de manifiesto la indicación de la radioterapia externa tanto en el carcinoma de páncreas irresecable y no metastásico como en los resecados. La asociación de radioterapia intraoperatoria tiene, así mismo, un papel importante en cuanto a supervivencia, paliación del dolor y de la progresión local. El 5-fluorouracilo asociado al tratamiento radioterápico prolonga significativamente la supervivencia con una morbilidad razonable
LAMP kit for diagnosis of non-falciparum malaria in Plasmodium ovale infected patients
Background: Microscopy and rapid diagnosis tests have a limited sensitivity in diagnosis of malaria by Plasmodium ovale. The LAMP kit (LoopAMP (R)) can be used in the field without special equipment and could have an important role in malaria control programmes in endemic areas and for malaria diagnosis in returned travellers. The performance of the Pan primer of the kit in detecting malaria by P. ovale was compared with the results of standard nPCR in samples of patients returning from P. ovale endemic areas. Methods: Plasmodium ovale positive samples (29, tested by PCR and/or microscopy) and malaria negative specimens (398, tested by microscopy and PCR) were collected in different hospitals of Europe from June 2014 to March 2016 and frozen at -20 degrees C. Boil and spin method was used to extract DNA from all samples and amplification was performed with LoopAMP (R) MALARIA kit (Eiken Chemical, Japan) in an automated turbidimeter (Eiken 500). The results of LAMP read by turbidimetry and with the naked eye were compared. Results: The kit showed a sensitivity of 100% and a specificity of 97.24% with positive and negative predictive values of 72.5 and 100%, respectively. Naked eyed readings were in accordance with turbidimetry readings (sensitivity, 92.5%, specificity, 98.96% and positive and negative predictive values, respectively, 90.24 and 99.22%). The limit of detection of LAMP assay for P. ovale was between 0.8 and 2 parasites/mu l. Conclusions: The Pan primer of the Malaria kit LoopAMP (R) can detect P. ovale at very low-levels and showed a predictive negative value of 100%. This tool can be useful in malaria control and elimination programmes and in returned travellers from P. ovale endemic areas. Naked eye readings are equivalent to automated turbidimeter readings in specimens obtained with EDTA.Peer reviewe
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