This article presents the main findings of an innovative Portuguese research project on prison guards' attitudes towards the prevention of sexual contacts between inmates. Sexuality in prisons is still a poorly-studied issue, although its increasing visibility demands a better understanding of prison dynamics. Results show that guards hold very favourable attitudes towards the prevention of forced sexual contacts between inmates, but they are more ambiguous concerning consensual sexuality. This result is influenced by the characteristics of the inmates under the guards' supervision and by the prison guards' knowledge of the existence of sexual contacts between inmates. The results will be discussed, along with their impact on the development of training programmes and policies regarding sexual contacts between inmates.
These processes still have limitation in achieving high yield and quality, and any commercial use of CNTs is limited due to these challenges encountered in large scale synthesis. [17] According to Shi et al. (2017), [18] "The poor reproducibility in CNT synthesis via CVD has been attributed to fluctuations in ambient and reactor-sorbed water vapor, as well as to carbonaceous deposits inside reactors leading to growth hysteresis." The presence of water or oxygen influences the growth gases and contributes to the formation or removal of carbon coated on the catalyst nanoparticles and avoiding this block deposition. The formation of carbon block coated on the catalyst nanoparticles prevents the CNT forests to grow taller, terminating the growth process. Thus, to obtain taller CNT forests, the lifetime of the catalyst should be prolonged. [17] The abrupt saturation point is observed for CNT growth rate controlled by laser with Meshot and Hart ( 2008). [19] The carbon atoms that reach the catalyst nanoparticles contribute to the CNT growth, but they also coat in form of amorphous carbon on the nanoparticle. Xiang et al. ( 2008) [20] refers to the growth limits of CNT carpets, explaining the diffusion mechanism of precursors for several different methods. Xiang et al. ( 2007) [21] refers the catalyst encapsulation occurs and it can be controlled during the growth changing the saturation point, creating a continuous growth mechanism. This deposition can be controlled by continuously supplying an etchant material that etches out the amorphous carbon coated on the catalyst nanoparticles. [17] The etchant materials generally used are CO 2 , H 2 O, and O 2 , however, excess levels of oxygencontaining compounds can result in etching of the CNTs themselves. [18] Sugime et al. ( 2021) [22] using the hot wire filament grew CNT around 14 cm but in this case the industrial growth is far in terms of reproducibility in quantity.Recently, Machado Jr. and Coelho (2021) [23] reported a novel method to obtain 140 µm tall VA-CNT forests, using a coldwall technique based on a two-phase deposition step. The first phase consists of the flow of NH 3 for a short period of time together with the C 2 H 2 flow to ensure catalyst activation. In the second phase, NH 3 flow is replaced by H 2 flow during the remaining growth time, permitting to obtain tall VA-CNT forests. In this work the saturation point was reached before the 40 min on deposition step in order to get 140 µm. Furthermore, the annealing temperature should be lower than the growth temperature to obtain taller forests. [24] Moreover, adding a third phase of H 2 during the deposition step at a temperature 50 °C above the previous phase, including a purge between each phase, allowed to achieve forests as high and uniform as This paper reports a multi-phase deposition for the growth of carbon nanotubes, intercalating phases of effective growth with purges of the reactor, based on the method recently proposed by the author to grow tall vertically aligned carbon nanotubes (VA-CNT) in a c...
A novel frequency modulated (FM) accelerometer based on piezoresistive resonators is presented. The accelerometer uses two differential resonators, connected to the accelerometer proofmass by an amplifying leverage mechanism. The piezoresistive double-mass resonators are electrostatically driven in anti-phase and the output signal is measured piezoresistively by applying a bias current to the connecting microbeam of the double-mass resonators. Accelerometers were fabricated using SOI technology with a 5 µm device layer. Fabricated resonators show a high resonance frequency around 705 kHz and a Q-factor close to 20,000 when measured in vacuum. Preliminary measurements show a sensitivity around 0.46 Hz/g for a single resonator.
Carbon nanotubes (CNTs), due to their unique properties, are suitable for application in biomedical devices. However these devices are not available in the market because of problems associated with biocompatibility and synthesis reproducibility. Indeed, the production of vertically aligned-carbon nanotubes (VA-CNTs) is needed for most of these applications. The most common synthesis method, Chemical Vapor Deposition (CVD), involves a large number of parameters, not all known, and their influence on the process is not fully understood. Knowing that the synthesis of CNTs is performed in a variety of lab conditions and in different furnace systems, which makes it impossible to create a universal recipe for use in all labs, this paper aims to start the design of an universal protocol that all labs can use to generate a suitable recipe for their environmental conditions and furnace system. The influence of parameters such as best deposition spot and tube baking was assessed. During this evaluation, the importance of other factors (catalyst uniformity and climacteric conditions) to the process has been revealed. The universal protocol suggested is in an early stage and needs to be improved.
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