Thermal neutral format based on the step technology

The exchange of models is one of the most serious problems currently encountered in the practice of spacecraft thermal analysis. Essentially, the problem originates in the diversity of computing environments that are used across different sites, and the consequent proliferation of native tool formats. Furthermore, increasing pressure to reduce the development's life cycle time has originated a growing interest in the so-called spacecraft concurrent engineering. In this context, the realization of the interdependencies between different disciplines and the proper communication between them become critical issues. The use of a neutral format represents a step forward in addressing these problems. Such a means of communication is adopted by consensus. A neutral format is not directly tied to any specific tool and it is kept under stringent change control. Currently, most of the groups promoting exchange formats are contributing with their experience to STEP, the Standard for Exchange of Product Model Data, which is being developed under the auspices of the International Standards Organization (ISO 10303). This paper presents the different efforts made in Europe to provide the spacecraft thermal analysis community with a Thermal Neutral Format (TNF) based on STEP. Following an introduction with some background information, the paper presents the characteristics of the STEP standard. Later, the first efforts to produce a STEP Spacecraft Thermal Application Protocol are described. Finally, the paper presents the currently harmonized European activities that follow up and extend earlier work on the area

Correction: CO2 induced phase transitions in diamine-appended metal-organic frameworks.

[This corrects the article DOI: 10.1039/C5SC01828E.]

Bilinear softening parameters and equivalent LEFM R-curve in quasibrittle failure

For composites and adhesive joints, the determination of the cohesive zone parameters from Double Cantilever Beam specimens loaded with pure moments is now well established and documented. However, for quasibrittle materials used in Civil Engineering such as concrete or wood, the difficulty to apply a pure bending moment lies inappropriated the method used for composites. Nevertheless, the one-to-one correspondence which exists between the R-curve and the softening curve is here revisited and adapted for any kind of specimen geometry and for the bilinear approximation of the softening function, well-known to successfully describe the failure of a wide group of quasibrittle materials. It is shown that even though the connections between the cohesive parameters and the ‘equivalent LEFM’ R-curve are geometry and material dependent, their trends are preserved whatever the specimen geometry and the material are. The outline of a general estimation procedure of the cohesive zone parameters funded on the equivalent LEFM R-curve is proposed

El discurso matemático del profesor: ejemplos, explicaciones y coherencia local

Se examina el discurso matemático de un profesor a lo largo de una discusión de clase, con inspiración en el marco MDI –Mathematical Discourse in Instruction. Se interpretan momentos de selección y secuenciación de ejemplos y explicaciones durante la resolución del problema del reparto de una apuesta en un juego interrumpido. Para ello, aplicamos una noción de coherencia local que alude al cumplimiento de condiciones sobre la selección, secuenciación y conexión de ejemplos y explicaciones. Se concluye que la coherencia local del discurso es mayor en los momentos en los cuales se aportan ejemplos con una función refutadora y desestabilizadora del razonamiento proporcional inicialmente utilizado por los alumnos, y a la vez explicaciones con una función modeladora hacia el concepto de probabilidad que se pretende introducir

Adaptive Dispersion Compensation for Remote Fiber Delivery of NIR Femtosecond Pulses

We report on remote delivery of 25 pJ broadband near-infrared femtosecond light pulses from a Ti:sapphire laser through 150 meters of single-mode optical fiber. Pulse distortion due to dispersion is overcome with pre-compensation using adaptive pulse shaping techniques, while nonlinearities are mitigated using an SF10 rod for the final stage of pulse compression. Near transform limited pulse duration of 130 fs is measured after the final compression.Comment: 3 pages, 4 figure

Functional output-controllability of time-invariant singular linear systems

In the space of finite-dimensional singular linear continuous-time-invariant systems described in the form \begin{equation}\label{eq1}\left . \begin{array}{rl} E \dot x(t)&= Ax(t)+Bu(t)\\ y(t)&=Cx(t)\end{array}{\kern-1mm}\right \}\end{equation} where $E,A\in M=M_{n}(\mathbb{C})$, $B\in M_{n\times m}(\mathbb{C})$, $C\in M_{p\times n}(\mathbb{C})$, functional output-controllability character is considered. A simple test based in the computation of the rank of a certain constant matrix that can be associated to the system is presentedPeer ReviewedPostprint (published version

Computational analysis of fire dynamics inside a wind turbine

Wind turbines are generally considered cost-effective, reliable and sustainable energy sources. Fires are not common in wind turbines, but a significant number of fires occur every year due to the large number of turbines installed. Wind turbine fires are difficult to extinguish hence significant damage is expected. Due to the unmanned operation, the probability of a turbine being occupied during a fire is very low. However, operators can do several tasks every week, and hence be exposed to a certain risk. Moreover, there is a general lack of information about how a fire develops inside a wind turbine and the subsequent evolution of the tenability conditions during the time required for an eventual evacuation. Gamesa has been working on fire safety since 2013, using CFD fire modelling to provide insights on wind turbine fire development for the design of emergency procedures. The paper describes a fire hazard analysis performed in a Gamesa’s 2.5 MW turbine. A CFD simulation is carried out to estimate the effects during the first minutes of a typical wind turbine fire in an electrical cabinet. Results show that average oxygen concentration at the nacelle remains above 19.5% during the first 10 min; temperature remains below 60°C for 12 min if measured at 1.5 m; and visibility is on average assured at heights lower than 1.5 m, with values above 5 m during the first 8 min in worse locations, implying no danger for personnel. The potential of this type of analysis to design safer wind turbines under performance-based approaches is clearly demonstrated.Peer ReviewedPostprint (author's final draft

Mapping mountain peatlands and wet meadows using multi-date, multi-sensor remote sensing in the Cordillera Blanca, Peru

Wetlands (called bofedales in the Andes of Peru) are abundant and important components of many mountain ecosystems across the globe. They provide many benefits including water storage, high quality habitat, pasture, nutrient sinks and transformations, and carbon storage. The remote and rugged setting of mountain wetlands creates challenges for mapping, typically leading to misclassification and underestimates of wetland extent. We used multi-date, multi-sensor radar and optical imagery (Landsat TM/PALSAR/RADARSAT-1/SRTM DEM-TPI) combined with ground truthing for mapping wetlands in Huascarán National Park, Peru. We mapped bofedales into major wetland types: 1) cushion plant peatlands, 2) cushion plant wet meadows, and 3) graminoid wet meadows with an overall accuracy of 92%. A fourth wetland type was found (graminoid peatlands) but was too rare to map accurately, thus it was combined with cushion peatland to form a single peatland class. Total wetland area mapped in the National Park is 38,444 ha, which is 11% of the park area. Peatlands were the most abundant wetland type occupying 6.3% of the park, followed by graminoid wet meadows (3.5%) and cushion wet meadows (1.3%). These maps will serve as the foundation for improved management, including restoration, and estimates of landscape carbon stocks

Effect of OAS genes on SARS-CoV-2 infection and the induction of innate immune responses

Resumen del trabajo presentado en el 8th European Congress of Virology, celebrado en Gdańsk (Polonia), del 4 al 7 de mayo de 2023Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) infections cause different clinical symptoms ranging from asymptomatic patients to patients suffering severe respiratory disease leading to death in some of them. Genetic and functional studies have shown inborn-errors of interferon (IFN)-related genes in severe COVID-19 patients explaining why some young patients devoid of co-morbidities succumbed to infection. In addition, very large genomic studies identified common genetic variants affecting the expression and splicing of IFN-stimulated genes (ISGs) of the 2",5"- oligoadenylate (2-5A) synthetase (OAS) family associated with COVID-19 severity. We have sequenced the whole genome of 274 patients who required hospitalization after SARS-CoV-2 infection, finding ultrarare mutations in OAS1 and OAS3 genes. Upon double-stranded (ds)RNA binding, the OAS1, OAS2, and OAS3 proteins synthetize 2¿- 5¿olygoadenylates which activate the endonuclease RNAseL. This endonuclease degrades viral and cellular RNAs, inhibiting viral replication. We have analyzed the effect of OAS1 and OAS3 genetic variants identified in our patients, and found that some of them impair the RNAseL activation. In addition, by using OAS3 knock-out cells generated in our laboratory and performing overexpression experiments, we have shown that OAS3 negatively modulates proinflammatory responses induced by immune challenges, and that the activation of the RNAseL activity seems necessary for this function. In addition, by using OAS3 knock-out mice infected with SARS-CoV-2 or treated with the double-stranded RNA analog poly(I:C), we have shown that OAS3 deficiency leads to a higher mouse susceptibility to SARS-CoV-2 infection and that OAS3 counteracts the induction of innate immune responses in the mouse infectedlungs, leading to a higher inflammatory response in OAS3 knock-out mice, compared to the parental mice. Given the contribution of exacerbated inflammatory responses to COVID-19 disease severity, our results suggest that OAS1/OAS3 could play a role limiting the severity of the clinical symptoms after SARS-CoV-2 infection

A record-linkage study of the development of hepatocellular carcinoma in persons with hepatitis C infection in Scotland

We investigated trends in first time hospital admissions and deaths attributable to hepatocellular carcinoma (HCC) in a large population based cohort of 22 073 individuals diagnosed with hepatitis C viral (HCV) infection through laboratory testing in Scotland in 1991 2006. We identified new cases of HCC through record linkage to the national inpatient hospital discharge database and deaths registry. A total of 172 persons diagnosed with HCV were admitted to hospital or died with first time mention of HCC. Hepatocellular carcinoma incidence increased between 1996 and 2006 (average annual change of 6.1, 95% confidence interval (CI):0.9 11.6%, P¼0.021). The adjusted relative risk of HCC was greater for males (hazard ratio¼2.7, 95% CI: 1.7 4.2), for those aged 60 years or older (hazard ratio ¼2.7, 95% CI: 1.9 4.1) compared with 50 59 years, and for those with a previous alcohol related hospital admission (hazard ratio¼2.5, 95% CI: 1.7 3.7). The risk of individuals diagnosed with HCV developing HCC was greatlyincreased compared with the general Scottish population (standardised incidence ratio¼127, 95% CI: 102 156). Owing to the advancing age of the Scottish HCV diagnosed population, the annual number of HCC cases is projected to increase, with a consequent increasing burden on the public healthcare system