Validade e reprodutibilidade do Wii Balance Board para avaliação do equilíbrio vertical estático: um novo método de avaliação.

The Wii Balance Board (WBB) began to be investigated as a low-cost alternative for assessing static balance in vertical posture. However, studies employed methodological procedures that did not eliminate result variability between the tests and equipment used. Objective: Determine the validity and reproducibility of the WBB as an instrument for assessing static balance in the vertical position, using simultaneous data analysis and superimposed equipment. Methods: This is an accuracy study of 29 healthy young individuals of both sexes aged 18 to 30 years. Subjects were assessed 24h apart (test-retest), using unipodal and bipodal support tests, with eyes closed and open. To that end the WBB was placed on top of a force platform (FP) and data (postural sway) were collected simultaneously on both devices. Validity and reproducibility were analyzed using the interclass correlation coefficient (ICC). Finally, Bland-Altman analysis was applied to assess agreement. Results: The sample was composed of 23 women and 6 men, with mean age of 24.2±6.3 years, 60.7±6.3 kg and 1.64±4.2 m. The validity of the WBB compared to the FP was excellent for all 4 tasks proposed (ICC = 0.93 0.98). The reproducibility analyzed by test-retest was excellent for the bipodal support tasks (ICC = 0.93-0.98) and only moderate for the unipodal support tests (ICC = 0.46 0.70). Graphic analysis exhibited good agreement between the devices, since most of the measures were within the limits of agreement. Conclusion: this study proved the validity and reproducibility of the Wii Balance Board as an instrument for assessing static balance in vertical posture, using simultaneous analysis with superimposed equipment. Thus, the WBB has been increasingly used by physical therapists and other health professionals in their clinical practice, as both a rehabilitation and assessment tool

Rational use of residential digesters for sewage treatment with Carbon Credits

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tecnologías emergentes aplicadas a la conservación de porotos (Phaseolus vulgaris L.)

La conservación de alimentos por tecnología de barreras es una alternativa de procesamiento, en la cual se aplican las técnicas de conservación tradicionales pero de una manera menos intensa, mediante una combinación de obstáculos a fin de mantener las cualidades organolépticas en el producto final. El objetivo de este trabajo fue desarrollar un método de conservación de porotos con la aplicación de tecnología de bajo costo y de aceptabilidad comparable al método convencional (Método Appert). La metodología que se empleó en la elaboración de conservas de porotos por tecnologías de barrera fue la siguiente: selección, lavado, remojado durante 24 horas, escurrido, cocinado a presión en salmuera al 0,5% durante cinco minutos a 121°C. Posteriormente se envasaron en recipientes esterilizados, se agregó la solución de relleno en ebullición (vinagre 7,50%, ácido láctico 0,30%, ácido ascórbico 0,35%, ácido cítrico 0,35%, sal 1,00% y azúcar 0,50%. No se esterilizó y se dejó enfriar hasta alcanzar la temperatura ambiente. La determinación de la calidad de las conservas elaboradas se realizó a los seis meses de almacenadas realizando una evaluación microbiológica, físicoquímica y sensorial. La conserva obtenida es aceptable, inocua y puede ser preservada a temperatura ambiente.

Medição do transporte sólido por arrastamento através de sensores acústicos

A quantificação do material sólido transportado (transporte sólido) ao longo de um curso de água é extremamente importante nas mais variadas áreas da engenharia fluvial. O transporte sólido em rios de montanha dá-se maioritariamente por arrastamento no fundo, através de deslizamento, rolamento e saltação dos sedimentos. Ao longo dos tempos foram desenvolvidas várias fórmulas para estimar o transporte sólido por arrastamento, contudo, devido à complexidade dos processos de transporte de sedimentos, bem como a variabilidade espacial e temporal, a previsão de taxas de transporte não foi conseguida exclusivamente através de investigação teórica. Para obter um melhor conhecimento sobre os processos de transporte sólido por arrastamento em rios de montanha, torna-se necessário monitorizá-los com maior precisão possível. Com os avanços na electrónica, novos métodos tecnológicos foram desenvolvidos para resolver a problemática da quantificação do transporte sólido, em detrimento dos atuais métodos tradicionais, que se baseiam na recolha de amostras em campo, para posterior correlação. O objetivo principal da presente dissertação foi o desenvolvimento de um equipamento capaz de estimar/monitorizar continuamente o transporte sólido por arrastamento em rios de montanha, que utilizasse tecnologia de baixo custo. Este equipamento dispõe de um sensor piezolelétrico que realizará medições à vibração causada pelo embate dos sedimentos sobre uma chapa metálica. A energia do sinal resultante dos impactos reverterá em peso. A metodologia usada para a obtenção das medições foi a realização de ensaios laboratoriais, tendo sido dado especial destaque à influência da variação do caudal, bem como da forma dos sedimentos, na intensidade do sinal adquirido.

SINGLE STAGE LED DRIVER TECHNOLOGY WITH LOW FREQUENCY RIPPLE CANCELLATION

Because of high efficacy, long lifespan, and environment-friendly operation, LED lighting devices become more and more popular in every part of our life, such as ornament/interior lighting, outdoor lightings and flood lighting. The LED driver is the most critical part of the LED lighting fixture. It heavily affects the purchasing cost, operation cost as well as the light quality. Design a high efficiency, low component cost and flicker-free LED driver is the goal. The conventional single-stage LED driver can achieve low cost and high efficiency. However, it inevitably produces significant twice-line-frequency lighting flicker, which adversely affects our health. The conventional two-stage LED driver can achieve flicker-free LED driving at the expenses of significantly adding component cost, design complexity and low the efficiency. The basic ripple cancellation LED driving method has been proposed in chapter three. It achieves a high efficiency and a low component cost as the single-stage LED driver while also obtaining flicker-free LED driving performance. The basic ripple cancellation LED driver is the foundation of the entire thesis. As the research evolving, another two ripple cancellation LED drivers has been developed to improve different aspects of the basic ripple cancellation LED driver design. The primary side controlled ripple cancellation LED driver has been proposed in chapter four to further reduce cost on the control circuit. It eliminates secondary side compensation circuit and an opto-coupler in design while at the same time maintaining flicker-free LED driving. A potential integrated primary side controller can be designed based on the proposed LED driving method. The energy channeling ripple cancellation LED driver has been proposed in chapter five to further reduce cost on the power stage circuit. In previous two ripple cancellation LED drivers, an additional DC-DC converter is needed to achieve ripple cancellation. A power transistor has been used in the energy channeling ripple cancellation LED driving design to successfully replace a separate DC-DC converter and therefore achieved lower cost. The detailed analysis supports the theory of the proposed ripple cancellation LED drivers. Simulation and experiment have also been included to verify the proposed ripple cancellation LED drivers.

Vortex configuration flow cell based on low temperature cofired ceramics as a compact chemiluminescence microsystern

The integration of optical detection methods in continuous flow microsystems can highly extend their range of application, as long as some negative effects derived from their scaling down can be minimized. Downsizing affects to a greater extent the sensitivity of systems based on absorbance measurements than the sensitivity of those based on emission ones. However, a careful design of the instrumental setup is needed to maintain the analytical features in both cases. In this work, we present the construction and evaluation of a simple miniaturized optical system, which integrates a novel flow cell configuration to carry out chemiluminescence (CL) measurements using a simple photodiode. It consists of a micro-mixer based on a vortex structure, which has been constructed by means of the low-temperature cofired ceramics (LTCC) technology. This mixer not only efficiently promotes the CL reaction due to the generated high turbulence but also allows the detection to be carried out in the same area, avoiding intensity signal losses. As a demonstration, a flow injection system has been designed and optimized for the detection of cobalt(H) in water samples. It shows a linear response between 2 and 20 mu M with a correlation of r > 0.993, a limit of detection of 1.1 mu M, a repeatability of RSD = 12.4 %, and an analysis time of 17 s. These results demonstrate the suitability of the proposal to the determination of compounds involved in CL reactions by means of an easily constructed versatile device based on low-cost instrumentation.

Cost-benefit analysis of alternative forms of hedgerow intercropping in the Philippine uplands

Considerable resources have been expended promoting hedgerow intercropping with shrub legumes to farmers in the Philippine uplands. Despite the resources committed to research and extension, persistent adoption by farmers has been limited to low cost versions of the technology including natural vegetation and grass strips. In this paper, cost-benefit analysis is used to compare the economic returns from traditional open-field maize farming with returns from intercropping maize between leguminous shrub hedgerows, natural vegetation strips and grass strips. An erosion/productivity model, Soil Changes Under Agroforestry, was used to predict the effect of erosion on maize yields. Key informant surveys with experienced maize farmers were used to derive production budgets for the alternative farming methods. The economic incentives revealed by the cost-benefit analysis help to explain the adoption of maize farming methods in the Philippine uplands. Open-field farming without hedgerows has been by far the most popular method of maize production, often with two or more fields cropped in rotation. There is little persistent adoption of hedgerow intercropping with shrub legumes because sustained maize yields are not realised rapidly enough to compensate farmers for establishment and maintenance costs. Natural vegetation and grass strips are more attractive to farmers because of lower establishment costs, and provide intermediate steps to adoption. Rural finance, commodity pricing and agrarian reform policies influence the incentives for maize farmers in the Philippine uplands to adopt and maintain hedgerow intercropping.

Wideband CMOS low noise amplifiers

Modern fully integrated receiver architectures, require inductorless circuits to achieve their potential low area, low cost, and low power. The low noise amplifier (LNA), which is a key block in such receivers, is investigated in this thesis. LNAs can be either narrowband or wideband. Narrowband LNAs use inductors and have very low noise figure, but they occupy a large area and require a technology with RF options to obtain inductors with high Q. Recently, wideband LNAs with noise and distortion cancelling, with passive loads have been proposed, which can have low NF, but have high power consumption. In this thesis the main goal is to obtain a very low area, low power, and low-cost wideband LNA. First, it is investigated a balun LNA with noise and distortion cancelling with active loads to boost the gain and reduce the noise figure (NF). The circuit is based on a conventional balun LNA with noise and distortion cancellation, using the combination of a common-gate (CG) stage and common-source (CS) stage. Simulation and measurements results, with a 130 nm CMOS technology, show that the gain is enhanced by about 3 dB and the NF is reduced by at least 0.5 dB, with a negligible impact on the circuit linearity (IIP3 is about 0 dBm). The total power dissipation is only 4.8 mW, and the active area is less than 50 x 50 m2 . It is also investigated a balun LNA in which the gain is boosted by using a double feedback structure.We propose to replace the load resistors by active loads, which can be used to implement local feedback loops (in the CG and CS stages). This will boost the gain and reduce the noise figure (NF). Simulation results, with the same 130 nm CMOS technology as above, show that the gain is 24 dB and NF is less than 2.7 dB. The total power dissipation is only 5.4 mW (since no extra blocks are required), leading to a figure-of-merit (FoM) of 3.8 mW

Quantifying, generating and mitigating radio interference in Low-Power Wireless Networks

Doctoral Programme in Telecommunication - MAP-tele

Technology, business models and network structure in the airline industry

Network airlines have been increasingly focusing their operations on hub airports through the exploitation of connecting traffic, allowing them to take advantage of economies of traffic density, which are unequivocal in the airline industry. Less attention has been devoted to airlines? decisions on point-to-point thin routes, which could be served using different aircraft technologies and different business models. This paper examines, both theoretically and empirically, the impact on airlines ?networks of the two major innovations in the airline industry in the last two decades: the regional jet technology and the low-cost business model. We show that, under certain circumstances, direct services on point-to-point thin routes can be viable and thus airlines may be interested in deviating passengers out of the hub.

Technology, business models and network structure in the airline industry

Network airlines have been increasingly focusing their operations on hub airports through the exploitation of connecting traffic, allowing them to take advantage of economies of traffic density, which are unequivocal in the airline industry. Less attention has been devoted to airlines' decisions on point-to-point thin routes, which could be served using different aircraft technologies and different business models. This paper examines, both theoretically and empirically, the impact on airlines' networks of the two major innovations in the airline industry in the last two decades: the regional jet technology and the low-cost business model. We show that, under certain circumstances, direct services on point-to-point thin routes can be viable and thus airlines may be interested in deviating passengers out of the hub. Keywords: regional jet technology; low-cost business model; point-to-point network; hub-and-spoke network JEL Classi…fication Numbers: L13; L2; L93

Assistive technology for visually impaired women for use of the female condom: a validation study

OBJECTIVE To validate assistive technology for visually impaired women to learn how to use the female condom. METHOD a methodological development study conducted on a web page, with data collection between May and October 2012. Participants were 14 judges; seven judges in sexual and reproductive health (1st stage) and seven in special education (2nd stage). RESULTS All items have reached the adopted parameter of 70% agreement. In Stage 1 new materials were added to represent the cervix, and instructions that must be heard twice were included in the 2nd stage. CONCLUSION The technology has been validated and is appropriate for its objectives, structure / presentation and relevance. It is an innovative, low cost and valid instrument for promoting health and one which may help women with visual disabilities to use the female condom.

Bridging the digital divide in developing countries: The role of mobile technology in bridging the digital divide

This thesis investigates how mobile technology usage could help to bring Information and communication technologies (ICT) to the people in developing countries. Some people in developing countries have access to use ICT while other people do not have such opportunity. This digital divide among people is present in many developing countries where computers and the Internet are difficult to access. The Internet provides information that can increase productivity and enable markets to function more efficiently. The Internet reduces information travel time and provides more efficient ways for firms and workers to operate. ICT and the Internet can provide opportunities for economic growth and productivity in developing countries. This indicates that it is very important to bridge the digital divide and increase Internet connections in developing countries. The purpose of this thesis is to investigate how can mobile technology and mobile services help to bridge the digital divide in developing countries. Theoretical background of this thesis consists of a collection of articles and reports. Theoretical material was gathered by going through literature on the digital divide, mobile technology and mobile application development. The empirical research was conducted by sending a questionnaire by email to a selection of application developers located in developing countries. The questionnaire’s purpose was to gather qualitative information concerning mobile application development in developing countries. This thesis main result suggests that mobile phones and mobile technology usage can help to bridge the digital divide in developing countries. This study finds that mobile technology provides one of the best tools that can help to bridge the digital divide in developing countries. Mobile technology can bring affordable ICT to people who do not have access to use computers. Smartphones can provide Internet connection, mobile services and mobile applications to a rapidly growing number of mobile phone users in developing countries. New low-cost smartphones empower people in developing countries to have access to information through the Internet. Mobile technology has the potential to help to bridge the digital divide in developing countries where a vast amount of people own mobile phones.

Ultrasonic and Electrokinetic Remediation of Low Permeability Soil Contaminated with Persistent Organic Pollutants

Electrokinetics has emerged as a potential technique for in situ soil remediation and especially unique because of the ability to work in low permeability soil. In electrokinetic remediation, non-polar contaminants like most organic compounds are transported primarily by electroosmosis, thus the process is effective only if the contaminants are soluble in pore fluid. Therefore, enhancement is needed to improve mobility of these hydrophobic compounds, which tend to adsorb strongly to the soil. On the other hand, as a novel and rapidly growing science, the applications of ultrasound in environmental technology hold a promising future. Compared to conventional methods, ultrasonication can bring several benefits such as environmental friendliness (no toxic chemical are used or produced), low cost, and compact instrumentation. It also can be applied onsite. Ultrasonic energy applied into contaminated soils can increase desorption and mobilization of contaminants and porosity and permeability of soil through developing of cavitation. The research investigated the coupling effect of the combination of these two techniques, electrokinetics and ultrasonication, in persistent organic pollutant removal from contaminated low permeability clayey soil (with kaolin as a model medium). The preliminary study checked feasibility of ultrasonic treatment of kaolin highly contaminated by persistent organic pollutants (POPs). The laboratory experiments were conducted in various conditions (moisture, frequency, power, duration time, initial concentration) to examine the effects of these parameters on the treatment process. Experimental results showed that ultrasonication has a potential to remove POPs, although the removal efficiencies were not high with short duration time. The study also suggested intermittent ultrasonication over longer time as an effective means to increase the removal efficiencies. Then, experiments were conducted to compare the performances among electrokinetic process alone and electrokinetic processes combined with surfactant addition and mainly with ultrasonication, in designed cylinders (with filtercloth separating central part and electrolyte parts) and in open pans. Combined electrokinetic and ultrasonic treatment did prove positive coupling effect compared to each single process alone, though the level of enhancement is not very significant. The assistance of ultrasound in electrokinetic remediation can help reduce POPs from clayey soil by improving the mobility of hydrophobic organic compounds and degrading these contaminants through pyrolysis and oxidation. Ultrasonication also sustains higher current and increases electroosmotic flow. Initial contaminant concentration is an essential input parameter that can affect the removal effectiveness.

Cost Reduction of Permanent Magnet Synchronous Machines

Electrical machine drives are the most electrical energy-consuming systems worldwide. The largest proportion of drives is found in industrial applications. There are, however many other applications that are also based on the use of electrical machines, because they have a relatively high efficiency, a low noise level, and do not produce local pollution. Electrical machines can be classified into several categories. One of the most commonly used electrical machine types (especially in the industry) is induction motors, also known as asynchronous machines. They have a mature production process and a robust rotor construction. However, in the world pursuing higher energy efficiency with reasonable investments not every application receives the advantage of using this type of motor drives. The main drawback of induction motors is the fact that they need slipcaused and thus loss-generating current in the rotor, and additional stator current for magnetic field production along with the torque-producing current. This can reduce the electric motor drive efficiency, especially in low-speed, low-power applications. Often, when high torque density is required together with low losses, it is desirable to apply permanent magnet technology, because in this case there is no need to use current to produce the basic excitation of the machine. This promotes the effectiveness of copper use in the stator, and further, there is no rotor current in these machines. Again, if permanent magnets with a high remanent flux density are used, the air gap flux density can be higher than in conventional induction motors. These advantages have raised the popularity of PMSMs in some challenging applications, such as hybrid electric vehicles (HEV), wind turbines, and home appliances. Usually, a correctly designed PMSM has a higher efficiency and consequently lower losses than its induction machine counterparts. Therefore, the use of these electrical machines reduces the energy consumption of the whole system to some extent, which can provide good motivation to apply permanent magnet technology to electrical machines. However, the cost of high performance rare earth permanent magnets in these machines may not be affordable in many industrial applications, because the tight competition between the manufacturers dictates the rules of low-cost and highly robust solutions, where asynchronous machines seem to be more feasible at the moment. Two main electromagnetic components of an electrical machine are the stator and the rotor. In the case of a conventional radial flux PMSM, the stator contains magnetic circuit lamination and stator winding, and the rotor consists of rotor steel (laminated or solid) and permanent magnets. The lamination itself does not significantly influence the total cost of the machine, even though it can considerably increase the construction complexity, as it requires a special assembly arrangement. However, thin metal sheet processing methods are very effective and economically feasible. Therefore, the cost of the machine is mainly affected by the stator winding and the permanent magnets. The work proposed in this doctoral dissertation comprises a description and analysis of two approaches of PMSM cost reduction: one on the rotor side and the other on the stator side. The first approach on the rotor side includes the use of low-cost and abundant ferrite magnets together with a tooth-coil winding topology and an outer rotor construction. The second approach on the stator side exploits the use of a modular stator structure instead of a monolithic one. PMSMs with the proposed structures were thoroughly analysed by finite element method based tools (FEM). It was found out that by implementing the described principles, some favourable characteristics of the machine (mainly concerning the machine size) will inevitable be compromised. However, the main target of the proposed approaches is not to compete with conventional rare earth PMSMs, but to reduce the price at which they can be implemented in industrial applications, keeping their dimensions at the same level or lower than those of a typical electrical machine used in the industry at the moment. The measurement results of the prototypes show that the main performance characteristics of these machines are at an acceptable level. It is shown that with certain specific actions it is possible to achieve a desirable efficiency level of the machine with the proposed cost reduction methods.