Comparative study of inner shelf sediments (Plio-Pleistocene and present day cover) in the Western Portuguese margin

A comparative study between Pliocene-Pleistocene and present day inner shelf deposits, considering both grain-size distribution and the present day hydrodynamic conditions, at west Portuguese Coastal Margin, is conducted. The modal grain-size analysis indicates that the west Portuguese Plio-Pleistocene inner shelf sediments are made of a mixture of several populations. The coarser populations (mode >0.5 mm, 1empty set) result from reworking of previous shoreface and beach deposits after storm events or are related with transgressive ravinement lags. The intermediate population, with modes around 0.125 to 0.250 mm (3 to 2empty set), should be in equilibrium with the hydrodynamic storm conditions in the inner shelf. This population is also the main constituent of the present day inner shelf cover between 10 and 25 meters depth. The finer population, with modes around 32 mu m (5empty set), is probably deposited from suspension during fair-weather periods. Under the high hydrodynamic winter storm conditions this population remains in suspension and tends to be mobilized to outer shelf locations by downward currents. It is expected that the mud size population proportion in bulk sediment should increases basinward, but this proportion may as well be influenced by post-depositional processes in ancient deposits

Threats and opportunities for workplace ergonomics in lean environments

Lean Management Systems (LMS) have become very popular among the manufacturing industry, services and large commercial areas. A LMS must develop and consider a set of work energizers to bring compatibility with workplace ergonomics, namely at a muscular, cognitive, and emotional demands level. The goal of this study is the identification of the most relevant impacts of a LMS adoption from the ergonomic point of view and cited in the literature and the synthesis of some possible drawbacks in workplace ergonomics due to a flawed application of the LMS. A final discussion about the most important, positive and negative, impacts are present at the end of the paper

Slot antenna design for a wirelessly powered implantable microcooler for neuronal applications

Implantable medical devices are becoming smaller by the day, with more efficient electronics and smaller power demands. Nevertheless, there are some applications in which power demands are inherently high, and solutions must be found in order to keep the devices as small as possible. In this paper, we propose an antenna to be used in wirelessly powering a focal brain cooling implant based on a Peltier device. This antenna is designed in order to act as a heatsink for the device with the goal of minimizing its final volume, therefore design constrains such as size limitations and geometry restrictions are considered.This work is supported by FCT with the reference project PTDC/EEI-TEL/5250/2014, by FEDER funds through Projecto 3599 - Promover a Producao Cientifica e Desenvolvimento Tecnologico e a Constituicao de Redes Tematicas (3599-PPCDT).info:eu-repo/semantics/publishedVersio

Characterization of chip-size electrically-small antennas for smart wireless biomedical devices

The new requirements for smarter and smaller biomedical microsystems demand for new integration technologies, including antenna integration. This can be solved with the use of microfabrication technologies, allowing the fabrication of chip-size antennas that may be placed on top of silicon wafers. However, due to their ultra-small physical dimensions and special operating conditions (e.g., covered with body tissue phantoms), antenna characterization requires the use of auxiliary custom-made transitions between antenna and test equipment, which are much larger than the antennas under test. Since electrically small antennas show also very small gain, the use of test boards may carry a significant impact on the antenna's characteristics. This paper presents a methodology used to investigate the performance of chip-size 3D antennas (500x500x500 mu m(3)) designed to operate inside the human body in the frequency band 1-8 GHz.This work was supported by Portuguese Foundation for Science and Technology: FCT-PTDC/EEI-TEL/2881/2012, Programa Operacional Temático Fatores de Competitividade (COMPETE) and Fundo Comunitário Europeu FEDER.info:eu-repo/semantics/publishedVersio

Performance assessment of wireless power transfer links for implantable microsystems

Wireless power transfer is a hot topic due to the growth of implanted device solutions which, as they get smaller and smarter, demand new solutions to power them up. These solutions need to keep the power level, namely SAR (specific absorption ratio) below a determined safety standard and to allow the device to be as small as possible. Current fabrication techniques allow the creation of ultra-small 3D antennas integrated on silicon wafers, which can lead to the miniaturization of implantable devices due to the possible reduction or even elimination of battery size. To evaluate this possibility, the antenna must be tested in conditions close to real working conditions, requiring the use of human body phantoms. This paper proposes a solution to measure the power received by an ultra-small antenna placed inside a phantom, without the use of coaxial cables attached to the device. Instead, an optoelectronic mechanism is used to route the received power to an optical fiber, and an optical spectrum analyzer is used to measure the received power.This work was supported by Portuguese Foundation for Science and Technology: FCT-PTDC/EEI-TEL/2881/2012, Programa Operacional Temático Fatores de Competitividade (COMPETE) and Fundo Comunitário Europeu FEDER.info:eu-repo/semantics/publishedVersio

Sand-spits systems from Benguela region (SW Angola). An analysis of sediment sources and dispersal from textural and compositional data

Sand spits are important coastline features in western Angola, but only limited knowledge on their recent evolution and sediment sources were obtained so far. The present study is focused on the Baía Farta and Lobito sand spits of coastal Benguela that develop to the north (i.e. downdrift) of the Coporolo and Catumbela river outlets. We used grain-size distributions, heavy-mineral suites and clay-mineral assemblages of sediments in the Coporolo-Baía Farta and Catumbela-Lobito coastal stretches to characterize the main depositional units and investigate sediment provenance. From the combined grain-size and mineralogical variability in mud and sand samples it is possible to infer sediment sources and dispersal in the two coastal stretches. Kaolinite is mainly derived from the Angola hinterland, and is particularly common in finer grained floodplain sediments from the Catumbela River. Expansive clays (smectite and illite-smectite mixed layers) are inferred to be mainly sourced by Meso-Cenozoic units of the Benguela Basin, being abundant in coarser grained fluvial deposits and in lagoonal deposits near Baía Farta. Sand supplied by the sedimentary units from Benguela Basin and their basement rocks tends to be enriched in epidote associated with blue-green hornblende. The Coporolo River sand is progressively diluted during the longshore northward transport by sand supplied by coastal units. Conversely, beach deposits in the Catumbela-Lobito coastal stretch are mainly sourced by the Catumbela River. A divergent longshore transport from Catumbela river-mouth occurs at Catumbela delta. Sand spit morphology and evolution reflect the patterns of dispersal of bedload and suspended load in settings of contrasting orography and human influence

Innocent heart murmurs

Innocent heart murmur is a frequent auscultatory finding in children. The diagnosis is essentially clinical, without need for further investigation. However, excluding heart disease can be a difficult task. This review article describes some features of medical history and physical examination that help in this differentiation. The role of diagnostic tests is also examined