Modelling the evaporation of cryogenic liquids in storage tanks

Cryogenic liquids are substances with a normal boiling point below -150°C. Recently, the interest in cryogenic liquids has skyrocketed because of their role in the energy transition, particularly for LNG and liquid hydrogen. Cryogenic liquids are stored in highly insulated tanks, which are nevertheless subject to heat ingress from the surroundings. The heat ingress drives thermal stratification, natural convection, pressure build-up and evaporation. Managing the evaporated cryogen, denominated boil-off gas (BOG), pose techno-economic, safety and environmental challenges. To facilitate the design and operation of cryogenic storage tanks, new models for cryogenic liquids evaporation have been developed. For isobaric storage, a 1-D model has been developed. The model includes wall heating, heat conduction and advection in the vapour phase. The model shows that advection dominates vapour heat transfer. A 2-D CFD model has been developed to validate the assumptions of the 1-D model. The CFD model validates the 1-D model assumption of one-dimensional advective flow. Additionally, the CFD model shows that thermal stratification dampens natural convection in the vapour. Analytical solutions of the 1-D model valid for the pseudo-steady state have been developed. The analytical solutions constitute an easy-to-use tool for practitioners to improve BOG management. For non-isobaric storage, a 1-D model that considers wall heating, heat conduction and wall boiling has been developed. The 1-D model demonstrates that wall boiling is relevant even for low heat fluxes. The 1-D model predictions were in good agreement with experimental pressure and vapour temperature profiles. The assumptions of the 1-D model have been validated by developing a new single-phase CFD model. A multiphase model has been developed to investigate interfacial transport phenomena. It shows that interfacial momentum transfer slightly enhances liquid heat transfer, and that vapour heating dominates pressure build-up at the beginning of the storage period.Open Acces

Influence of crystallographic orientation of biogenic calcite on <i>in situ</i> Mg XANES analyses

Micro X-ray absorption near-edge spectroscopy at the Mg &lt;i&gt;K&lt;/i&gt;-edge is a useful technique for acquiring information about the environment of Mg&lt;sup&gt;2+&lt;/sup&gt; in biogenic calcite. These analyses can be applied to shell powders or intact shell structures. The advantage of the latter is that the XANES analyses can be applied to specific areas, at high (e.g. micrometre) spatial resolution, to determine the environment of Mg&lt;sup&gt;2+&lt;/sup&gt; in a biomineral context. Such in situ synchrotron analysis has to take into account the potential effect of crystallographic orientation given the anisotropy of calcite crystals and the polarized nature of X-rays. Brachiopod shells of species with different crystallographic orientations are used to assess this crystallographic effect on &lt;i&gt;in situ&lt;/i&gt; synchrotron measurements at the Mg &lt;i&gt;K&lt;/i&gt;-edge. Results show that, owing to the anisotropy of calcite, &lt;i&gt;in situ&lt;/i&gt; X-ray absorption spectra (XAS) are influenced by the crystallographic orientation of calcite crystals with a subsequent potentially erroneous interpretation of Mg&lt;sup&gt;2+&lt;/sup&gt; data. Thus, this study demonstrates the importance of crystallography for XAS analyses and, therefore, the necessity to obtain crystallographic information at high spatial resolution prior to spectroscopic analysis

A realistic vapour phase heat transfer model for the weathering of LNG stored in large tanks

A new non-equilibrium model relevant to LNG weathering in large storage tanks under constant pressure has been developed. It treats the heat influx from the surroundings into the vapour and liquid phases separately and allows for heat transfer between the two phases. The main heat transfer mechanisms in the vapour phase are assumed to be advection, due to upward flow of evaporated LNG, and conduction. It has been observed that the vapour temperature increases monotonically as a function of the height, in agreement with recent experimental results. In all the simulations performed the vapour to liquid heat transfer was small, also in line with recent experimental findings, and is estimated to contribute less than 0.3% to boil-off gas rates. The results of this work indicate that the heat transfer by the advective upward flow dominates the energy transfer within the vapour, while the natural convection, in the body of the vapour, can be neglected. The initial liquid filling has a pronounced effect on all the relevant variables, leading to a decrease in vapour temperature and boil-off gas temperature and an increase in boil-off rates. A rule of thumb for estimating the boil-off gas temperature in industrial storage tanks is provided

Enforced disappearance as a form of psychological torture: Evidence from the Ayotzinapa Case (México)

Abstract Objective: To analyse the impacts of forced disappearance as a form of psychological torture in the forced disappearance of students known as the Ayotzinapa Case (Mexico). To make visible the effects of impunity. Method: Historical and documentary analysis. Interviews with two groups of people affected: 1) relatives of the 43 young students who disappeared; 2) young students that survived. Analysis of the information obtained from the group and individual clinical interventions carried out during three months. Results. In both groups, various impacts related to political violence were identified, in particular forced disappearance, which leads us to consider that the criteria for torture are fulfilled and especially the elements derived from the subsequent re-victimising action of the State in the investigations and the impunity derived from the lack of access to justice and truth. Conclusion: In addition to the enforced disappearance itself and its impacts, the suffering resulting from the State’s subsequent processes must be analysed. Keywords: Psychological torture, forced disappearance, impunity.  ___________________________________________________________________________________________________ Español El artículo tiene como propósito analizar los indicios de tortura psicológica en los familiares de los desaparecidos y los estudiantes sobrevivientes del caso de Ayotzinapa, a raíz de la desaparición forzada, la ejecución extrajudicial  de los estudiantes y los mecanismos de impunidad liderados por el estado. Se utilizó como metodología, el análisis del discurso de las víctimas a través intervenciones clínicas grupales e individuales durante 3 meses. Los resultados de las entrevistas mostraron sentimientos de humillación, culpa y deterioro a nivel físico, psicológico, familiar  y social a raíz de los eventos ocurridos el 26 de septiembre, así como el incremento del deterioro derivado de la falta de justicia, la criminalización y la impunidad por parte de funcionarios del estado. Por lo tanto se concluye que si hay incidencia de tortura psicológica en las víctimas del caso de Ayotzinapa. El trabajo busca evidenciar la relación entre la tortura psicológica y la desaparición forzada en los familiares.   Keywords: Tortura psicológica, desaparición forzada y ejecución extrajudicial.

Oxygen isotope equilibrium in brachiopod shell fibres in the context of biological control

No abstract available

Diagnóstico Estratégico de la empresa Beneficio de Café y Arroz La Dalia del Municipio La Dalia, departamento de Matagalpa, durante el año 2014

El presente trabajo investigativo radica en el Tema General: Diagnóstico Estratégico para la pequeña y mediana empresa (PYMES) del departamento de Matagalpa durante el año 2014. Dichas estrategias contribuyen como un medio de competitividad en las pequeñas y medianas empresas, además son una herramienta fundamental que apoya el alcance de metas y objetivos para el desarrollo de las mismas. Del tema general se aborda Diagnóstico Estratégico de la empresa Beneficio de Café y Arroz La Dalia del Municipio La Dalia, departamento de Matagalpa durante el año 2014. Con este documento se pretende determinar la situación actual de la empresa e identificar las diferentes estrategias que se aplican en la organización además de llevar a cabo una valoración de estas estrategias para la formulación de un Plan Estratégico. Se aborda información mediante la que se identificó que en la empresa se han llevado a cabo Estrategias Genéricas de Diferenciación y alta Segmentación, Penetración de Mercado, Integración hacia Delante, Diversificación Concéntrica y Recorte de Gastos. Por lo tanto las estrategias más factibles para empezar un plan estratégico serían una estrategia funcional para solucionar problemas de organización, ya que es una de las principales debilidades, también diversificación horizontal teniendo en cuenta que sus clientes la demandan, así como continuar fortaleciendo las estrategias que se están implementand

Palaeoenvironmental signatures revealed from rare earth element (REE) compositions of vertebrate microremains of the Vesiku Bone Bed (Homerian, Wenlock), Saaremaa Island, Estonia

The Estonian Journal of Earth Sciences is an open access journal and applies the Creative Commons Attribution 4.0 International License CC BY to all its papers (http://creativecommons.org/licenses/by/4.0/). The attached file is the published version of the article

The Impact of TARP Bailouts on Stock Market Volatility and Investor Fear

The Emergency Economic Stabilization Act of 2008 was the response of the Federal government to the economic crisis of 2007-2009. Within this act, the Troubled Asset Relief Program (TARP) was the mechanism to attempt to stabilize the financial market through the injection of liquidity into troubled firms. This paper examines the effect of TARP bailouts on stock market volatility and investor fear. Using an event study methodology, we find evidence of a significant decrease in stock-market volatility on the day of bailouts, and the day after. Additionally, findings show that the VIX, a proxy of investor fear, significantly declines on the second day subsequent to bailouts. The results suggest that government intervention, in the form of bailouts, is successful in stabilizing financial markets and reducing investor anxiety in the short-run

Begomovirus quasispecies adapt to hosts by exploring different sequence space without changing their consensus sequences

Geminiviruses possess single-stranded circular DNA genomes that depend on cellular polymerases for replication in the host nucleus. In plant hosts, geminivirus populations behave as ensembles of mutant and recombinant genomes. This favours the emergence of new geminivirus strains able to produce new diseases or overcome the genetic resistance of cultivars. In warm and temperate areas several whitefly-transmitted geminiviruses of the genus Begomovirus cause the tomato yellow leaf curl disease (TYLCD) with important economic consequences. TYLCD is frequently controlled in commercial tomato production using the Ty-1 resistance gene. Over a 45 day period we studied the evolution of infectious clones from three TYLCD-associated begomoviruses: Tomato yellow leaf curl Sardinia virus, Tomato yellow leaf curl virus and the recombinant Tomato yellow leaf curl Axarquia virus. The evolution of their viral progeny was examined in susceptible tomato (ty1/ty1), resistant tomato (Ty1/ty1), common bean, and the wild reservoir Solanum nigrum. We found that in addition to affecting viral accumulation kinetics, the host influenced the sequence space explored by these begomoviruses. In tomato, viral dynamics was not influenced by the presence of the Ty-1 gene. Interestingly, positive adaptation of the coat protein gene was only observed in the common bean and S. nigrum, which correlates with these plants having viral quasispecies with the highest degree of complexity and heterogeneity. Our results underline the importance of analysing the mutant spectra of begomovirus infections, especially in wild reservoirs, which have the potential to give rise to large numbers of emergent variants in spite of the invariance of their consensus sequences.Junta de Andalucía proyecto: P10-CVI-6561. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech