Control of the deposition ratio of Bi2Te3 and Sb2Te3 in a vacuum evaporator for fabrication of Peltier elements

This article reports the main problem and the corresponding solution of the co-evaporation of Bi2Te3 and Sb2Te3 films for the fabrication of Peltier elements. This main problem consists in the control of the deposition rates of the two elements: Bi or Sb and Te, which have very different vapor pressures. The control of the deposition ratio was achieved by means of a PID controller, which permitted the fabrication of thin-film Peltier elements that produce a temperature gradient in the order of 2C between their hot and cold junctions, when measured at free air conditions.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/18142/2004.Agencia de Inovação (MPYROM)

Clinical, Molecular Characterization and Long-Term Follow-Up of a Patient with Neonatal Severe Hyperparathyroidism

Heterozygous inactivating pathogenic variants of the calcium-sensing receptor encoding gene cause autosomal dominant familial hypocalciuric hypercalcemia, whereas mutations that inactivate both alleles cause neonatal severe hyperparathyroidism, a rare and potentially fatal disease. We present the clinical and genetic characterization of a Portuguese family with familial hypocalciuric hypercalcemia/neonatal severe hyperparathyroidism as well as the long-term follow-up of the proband. The newborn was admitted due to progressive hypotonia, feeding refusal, and dehydration. Serum calcium and parathormone levels were markedly increased. Radiological evaluation revealed osteopenia and several fractures. Total parathyroidectomy with the reimplantation of a quarter of one gland was performed. At 15 years old, she is clinically well, has normal calcium levels, and detectable parathormone values while under calcium and α-calcidiol treatment. Calcium-sensing receptor encoding gene sequencing revealed a germline homozygous nonsense pathogenic variant later confirmed as inherited.info:eu-repo/semantics/publishedVersio

Transformerless series active power filter to compensate voltage disturbances

This paper presents a transformerless topology of series active power filter with capability to protect sensitive loads against harmonics, sags, swells and unbalances of the power system voltages. The proposed topology is constituted by three isolated H-bridge with a voltage source at the DC side. The series active power filter has been studied with the help of PSIM (Power Simulation software) and simulation results are presented. A laboratory prototype is under development and experimental results are shown.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/EEA-EEL/104569/200

Simulations of a Current-Source Shunt Active Power Filter with Carrier-Based PWM and Periodic Sampling modulation techniques

Bruno Exposto, Helder Carneiro, J. G. Pinto, Carlos Couto, João L. Afonso, "Simulations of a current-source Shunt Active Power Filter with Carrier-Based PWM and Periodic Sampling Modulation Techniques" Proceedings of the 2011-14th European Conference on Power Electronics and Applications (EPE 2011), pp.1-8, 30 Aug. – 1 Sept., 2011.This paper presents a Shunt Active Power Filter that is built using a current-source inverter. The control of the Active Filter relies in the p-q Theory with the “Sinusoidal Currents at Source” algorithm implemented. The Active Power Filter was simulated using two modulation techniques: Periodic Sampling and Carrier-Based Pulse Width Modulation (CBPWM). To assess the performance of the Active Filter, the simulations were made using two different loads. The first load was a RL balanced load. The second was a non-linear load, namely a full bridge rectifier with a RL load in the DC side. These loads allowed determining the performance of the Active Filter when compensating current harmonics and power factor, using the two modulation techniques.This work is financed by FEDER Funds, through the Operational Programme for Competitiveness Factors – COMPETE, and by National Funds through FCT – Foundation for Science and Technology of Portugal, under the project PTDC/EEA-EEL/104569/2008

On-chip array of thermoelectric peltier microcoolers

This article reports on the theoretical modelling, the Finite Element Modelling (FEM) simulation, the fabrication process and preliminary results of the first on-chip thermoelectric microcooler array (64 pixels arranged in a 8×8 array), with each pixel independently controlled. This microcooler array uses co-evaporated V–VI compounds of Bi2Te3 and Sb2Te3 as thermoelectric layers, and can be fabricated using planar thin-film technology, lithography and wet etching, on top of a silicon wafer where the CMOS electronic circuits were previously made

A miniaturized self-calibrated pyrometer microsystem

paper describes the design, modeling and optimization of a miniaturized self-calibrated pyrometer to detect infrared radiation (in 5-20 µm range of wavelengths) in order to measure the real temperature of objects without contact. The microsystem consists of a thermally insulated absorbing area and two thermopiles with the hot junctions in the absorbing area and the cold junctions on a heat sink (i.e. the silicon bulk). The complete microsystem is in silicon planar technology and each thermopile has a different reference temperature, biased by a Peltier microstructure near to the cold junction of the thermopile. A silicon die passivated with a silicon nitride membrane is the ground floor of all microsystem. The absorbing area, a black gold strip on the silicon nitride membrane is obtained by anisotropic etching of the bulk silicon from the back of the wafer. The pyrometer microsystem is composed by: the IR optical filter on the top, the electronic system built in CMOS technology added by Multi-Chip-Module (MCM) techniques and the pyrometer. Application of a network of pyrometers in textile industry is the final goal.Fundação para a Ciência e a Tecnologia (FCT

Congenital Lobar Emphysema: A Multilobar Presentation

O enfisema lobar congénito é umamalformação rara do tracto respiratório inferior detectada habitualmente nos primeiros meses de vida. Apresenta-se o caso de um lactente, do sexo masculino, de dois meses de idade, internado por suspeita de pneumonia, no qual a segunda radiografia de tórax revelou hipertransparência arredondada no lobo inferior esquerdo, sugestiva de enfisema lobar congénito. A tomografia computorizada torácica mostrou uma imagem quística,multilobar, e a broncoscopia excluiu obstrução brônquica. Foi programada cirurgia para os seis meses de idade, mas aos três meses foi submetido a intervenção cirúrgica urgente por pneumotórax hipertensivo. O exame anatomo-patológico da peça operatória permitiu o diagnóstico de enfisema lobar congénito. Destaca-se a apresentação multilobar e a complicação por pneumotórax