Perfomance analysis of hybrid systems based on externally heayed closed-cycle engines

This work presents a comparative analysis of hybrid systems that make use of closed-cycle externally heated bottoming systems. Two options are considered: reciprocating (Stirling) engines and supercritical carbon dioxide turbines. These engines share the common feature of working on closed cycles with optimised fluids (H2 and CO2 respectively). However, they differ in their internal structure: Stirling engines make use of volumetric machinery whereas the SCO2 system is composed by turbomachinery. In both cases, the working fluid is subjected to very high pressure and temperature in the range of 50-200 bar and 40-650 ºC. A brief description of both bottoming systems is provided in the article along with the expected performance of each case in on-design and off-design (part load) conditions. The analysis is therefore split into two stages. First, a comparison is shown for on-design operation aiming to evaluate the maximum efficiency attainable by the proposed systems. Second, a preliminary analysis of off-design operation is presented. The paper concludes that hybrid systems based on atmospheric fuel cells and externally heated closed-cycle bottoming engines have the potential to outperform conventional pressurised fuel cells and gas turbines hybrids while preserving the topping system from the demanding operating conditions of the latter configuratio

Silicon carbide particulates incorporated into microalloyed steel surface using TIG: microstructure and properties

Surface metal matrix composites have been developed to enhance properties such as erosion, wear and corrosion of alloys. In this study, ~5 µm or ~75 µm SiC particulates were preplaced on a microalloyed steel. Single track surface zones were melted by a tungsten inert gas torch, and the effect of two heat inputs, 420Jmm-1 and 840 Jmm-1,compared. The results showed that the samples melted using 420Jmm-1 were crack-free. Pin-on-disk wear testing under dry sliding conditions were conducted. The effects of load and sliding velocity were used to characterise the performance of the crack-free samples. Microstructural and X-ray diffraction studies of the surface showed that the SiC had dissolved, and that martensite, was the main phase influencing the hardness

International lower limb collaborative (INTELLECT) study: a multicentre, international retrospective audit of lower extremity open fractures

Trauma remains a major cause of mortality and disability across the world1, with a higher burden in developing nations2. Open lower extremity injuries are devastating events from a physical3, mental health4, and socioeconomic5 standpoint. The potential sequelae, including risk of chronic infection and amputation, can lead to delayed recovery and major disability6. This international study aimed to describe global disparities, timely intervention, guideline-directed care, and economic aspects of open lower limb injuries

Potential of ORC Systems to Retrofit CHP Plants in Wastewater Treatment Stations

Wastewater treatment stations take advantage of the biogas produced from sludge in anaerobic digesters to generate electricity (reciprocating gas engines) and heat (cooling water and engine exhaust gases). A fraction of this electricity is used to operate the plant while the remaining is sold to the grid. Heat is almost entirely used to support the endothermic anaerobic digestion and a minimum fraction of it is rejected to the environment at a set of fan coolers. This generic description is applicable to on-design conditions. Nevertheless, the operating conditions of the plant present a large seasonal variation so it is commonly found that the fraction of heat rejected to the atmosphere increases significantly at certain times of the year. Moreover, the heat available in the exhaust gases of the reciprocating engine is at a very high temperature (around 650 ºC), which is far from the temperature at which heat is needed for the digestion of sludge (around 40 ºC in the digesters). This temperature difference offers an opportunity to introduce an intermediate system between the engines and the digesters that makes use of a fraction of the available heat to convert it into electricity. An Organic Rankine Cycle (ORC) with an appropriate working fluid is an adequate candidate for these hot/cold temperature sources. In this paper, the techno-economic effect of adding an Organic Rankine Cycle as the intermediate system of an existing wastewater treatment station is analysed. On this purpose, different working fluids and system layouts have been studied for a reference wastewater treatment station giving rise to optimal systems configurations. The proposed systems yield very promising results with regard to global efficiency and electricity production (thermodynamically and economically)

High-content screening of natural products reveals novel nuclear export inhibitors

Natural products are considered an extremely valuable source for the discovery of new drugs against diverse pathologies. As yet, we have only explored a fraction of the diversity of bioactive compounds, and opportunities for discovering new natural products leading to new drugs are huge. In the present study, U2nesRELOC, a previously established cell-based imaging assay, was employed to screen a collection of extracts of microbial origin for nuclear export inhibition activity. The fluorescent signal of untreated U2nesRELOC cells localizes predominantly to the cytoplasm. Upon treatment with the nuclear export inhibitor leptomycin B, the fluorescent-tagged reporter proteins appear as speckles in the nucleus. A proprietary collection of extracts from fungi, actinomycetes, and unicellular bacteria that covers an uncommonly broad chemical space was used to interrogate this nuclear export assay system. A two-step image-based analysis allowed us to identify 12 extracts with biological activities that are not associated with previously known active metabolites. The fractionation and structural elucidation of active compounds revealed several chemical structures with nuclear export inhibition activity. Here we show that substrates of the nuclear export receptor CRM1, such as Rev, FOXO3a and NF-B, accumulate in the nucleus in the presence of the fungal metabolite MDN-0105 with an IC50 value of 3.4 mu M. Many important processes in tumor formation and progression, as well as in many viral infections, critically depend on the nucleocytoplasmic trafficking of proteins and RNA molecules. Therefore, the disruption of nuclear export is emerging as a novel therapeutic approach with enormous clinical potential. Our work highlights the potential of applying high-throughput phenotypic imaging on natural product extracts to identify novel nuclear export inhibitors.Fundacion MEDINA; MICINN [PCT-010000-2010-3]info:eu-repo/semantics/publishedVersio

Standards for the Use of Enteral Nutrition in Patients with Diabetes or Stress Hyperglycaemia: Expert Consensus

(1) Background: Hyperglycaemia that occurs during enteral nutrition (EN) should be prevented and treated appropriately since it can have important consequences for morbidity and mortality. However, there are few quality studies in the literature regarding the management of EN in this situation. The objective of this project was to attempt to respond, through a panel of experts, to those clinical problems regarding EN in patients with diabetes or stress hyperglycaemia (hereinafter referred to only as hyperglycaemia) for which we do not have conclusive scientific evidence; (2) Methods: The RAND/UCLA Appropriateness Method, a modified Delphi panel method, was applied. A panel of experts made up of 10 clinical nutrition specialists was formed, and they scored on the appropriateness of EN in hyperglycaemia, doing so in two rounds. A total of 2992 clinical scenarios were examined, which were stratified into five chapters: type of formula used, method of administration, infusion site, treatment of diabetes, and gastrointestinal complications. (3) Results: consensus was detected in 36.4% of the clinical scenarios presented, of which 23.7% were deemed appropriate scenarios, while 12.7% were deemed inappropriate. The remaining 63.6% of the scenarios were classified as uncertain; (4) Conclusions: The recommendations extracted will be useful for improving the clinical management of these patients. However, there are still many uncertain scenarios reflecting that the criteria for the management of EN in hyperglycaemia are not completely standardised. More studies are required to provide quality recommendations in this area