Supergiant Barocaloric Effects in Acetoxy Silicone Rubber over a Wide Temperature Range: Great Potential for Solid-state Cooling

Solid-state cooling based on caloric effects is considered a viable alternative to replace the conventional vapor-compression refrigeration systems. Regarding barocaloric materials, recent results show that elastomers are promising candidates for cooling applications around room-temperature. In the present paper, we report supergiant barocaloric effects observed in acetoxy silicone rubber - a very popular, low-cost and environmentally friendly elastomer. Huge values of adiabatic temperature change and reversible isothermal entropy change were obtained upon moderate applied pressures and relatively low strains. These huge barocaloric changes are associated both to the polymer chains rearrangements induced by confined compression and to the first-order structural transition. The results are comparable to the best barocaloric materials reported so far, opening encouraging prospects for the application of elastomers in near future solid-state cooling devices.Comment: 19 pages, 7 figures, 2 table

Numerical validation of Ehrenfest theorem in a Bohmian perspective for non-conservative systems

In this work we make a high precision numerical study of the Ehrenfest theorem using the Bohmian approach, where we obtain classical solutions from the quantum trajectories performing the Bohmian averages. We analyse the one-dimensional quantum harmonic and Duffing oscillator cases, finding numerical solutions of the time-dependent Schr\"odinger equation and the guidance equation for different sets of initial conditions and connects these results with the corresponding classical solutions. We also investigate the effect of introducing external forces of three types: a simple constant force, a fast-acting Gaussian impulse, and an oscillatory force with different frequencies. In the last case the resonance in the quantum trajectories was observed.Comment: 13 pages and 11 figure

Cores e corantes dos bordados de Castelo Branco: interação de contextos formais e não formais na educação em química

Els brodats de colors de Castelo Branco (Portugal) van ser objecte del desenvolupament d'un projecte per millorar la relació entre l'educació formal i no formal en química i en la formació de professors i divulgadors de la cultura. La qüestió principal se centra en la possibilitat d'identificar i obtenir els tints antics i actuals que s'utilitzen per tenyir la seda. Es presenten dues activitats experimentals: l'extracció d'un colorant natural i l'ús de mordent amb un tint sintètic.The colourful embroidery of Castelo Branco (Portugal) was the theme for the development of a project that enhances the relationship between formal and non-formal contexts in chemistry education and in the training of teachers and cultural animators. The central question concerns the possibility of identifying and obtaining the old and modern dyes that are used for dyeing silk. We present two experimental activities: extraction of a natural dye and use of mordant with a synthetic dye

Subaortic Stenosis Following Anatomic Correction for Transposition of the Great Arteries

Os autores descrevem o caso clínico de uma criança do sexo masculino, com 12 anos de idade, com diagnóstico pós-natal de transposição das grandes artérias com comunicação interventricular, submetida a switch arterial e encerramento da comunicação interventricular. Durante o seguimento pós-operatório detectou-se um obstáculo entre o ventrículo esquerdo e a aorta ascendente que foi, inicialmente, de grau ligeiro. No último ano começou a referir sintomatologia (cansaço para esforços moderados). Na avaliação efectuada detectou-se uma estenose aórtica subvalvular grave, tendo o doente sido submetido a tratamento cirúrgico, com bom resultado. A estenose aórtica subvalvular é uma complicação rara, que tem sido descrita em estudos de follow-up de switch arterial, sobretudo nas situações em que o defeito primário é a transposição das grandes artérias com comunicação interventricular

A lean case study in an oncological hospital: implementation of a telephone triage system in the emergency service

Abstract: Lean practices and thinking have increased substantially in the last few years. Applications of lean practices to health care are found worldwide. Despite that, new contributions are required because the application of lean thinking to hospitals has a long way to go. Lean practices and thinking do not include, in the literature or practice programs, any references to triage systems in health care units. The common triage systems require physical presence, but there are alternative methods to avoid the need to move patients: these alternative triage systems, given their characteristics, may be included in the spectrum of lean practices. Currently, patients that are already known to suffer from cancer are encouraged to go to hospital (public or private, with an oncological focus) when facing side effects from chemotherapy or radiation treatments; they are then submitted to a triage system (present themselves to the hospital for examination). The authors of this paper propose the introduction of telephone or email triage for impaired patients as a valid substitute for moving them physically, thereby often avoiding several unnecessary moves. This approach has, in fact, characteristics similar to a lean practice in that it reduces costs and maintains, if done properly, the overall service offered. The proposed ‘remote’ triage emerged from the results of a large survey sent to patients and also as the outcome of a set of semistructured interviews conducted with hospital nurses. With the results they obtained, the authors felt comfortable proposing this approach both to public and private hospitals, because the study was conducted in the most important, largest, and best-known oncological unit in Spain. As a final result, the health care unit studied is now taking the first steps to implement a remote triage system by telephone, and has begun to reduce the previously necessary movement of impaired patients

Quality control of gasohol using a micro-unit for membraneless gas diffusion

This work describes the development of a new spectrophotometric flow technique suitable for monitoring of ethanol content in gasohol fuel. Membraneless gas-diffusion (MBL-GD) was applied with one-step aqueous extraction of gasohol (1:2 gasohol/water). Segments of aqueous extract and color developing reagent were allowed to flow into two separate channels in the MBL-GD device. Inside the device, ethanol vapor can diffuse across a small headspace between the two channels (donor and acceptor). Introduction of an air-segment behind the zone of acceptor reagent to stop dispersion of the colored zone greatly improves the rapidity of analysis using this MBL-GD technique. Two methods were developed for quality control of gasohol by measuring ethanol content. Method I is suitable for direct calibration of E5 and E10. Method II is recommended for E20. These methods have high accuracy with good precision (% RSD: 1 to 4.9, n&#8201;=&#8201;45) and have a sample throughput of 26 samples per hour. E10 samples were compared with analysis using a standard GC method. </p

The Unruh effect under the de Broglie-Bohm perspective

We investigate the Minkowski ground state associated with a real massless scalar field as seen by an accelerated observer under the perspective of the de Broglie-Bohm quantum theory. We use the Schr\"odinger picture to obtain the wave functional associated with the Minkowski vacuum in Rindler coordinates, and we calculate the field trajectories through the Bohmian guidance equations. The Unruh temperature naturally emerges from the calculus of the average energy, but the Bohmian approach precisely distinguishes between its quantum and classical components, showing that they periodically interchange their roles as the dominant cause for the temperature effects, with abrupt jumps in the infrared regime. We also compute the power spectra, and we exhibit a very special Bohmian field configuration with remarkable physical properties.Comment: 32 pages, 6 figure