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BackgroundAlthough complications of obesity are well acknowledged and managed by clinicians, management of obesity itself is often difficult, which leads to its underdiagnosis and undertreatment in hospital settings. However, tools that could improve the management of obesity, including self-monitoring, engagement with a social network, and open channels of communication between the patient and doctor, are limited in a clinic-based setting. ObjectiveThe objective of our study was to evaluate the usability and acceptability of a newly developed mobile app linked with an accelerometer and its early effects on patient-doctor relationships. MethodsFrom September 2013 to February 2014, we developed a mobile app linked with an accelerometer as a supportive tool for a clinic-based weight loss program. The app used information from electronic health records and delivered tailored educational material. Personal goal setting, as well as monitoring of weight changes and physical activity combined with feedback, are key features of the app. We also incorporated an interactive message board for patients and doctors. During the period of March 2014 to May 2014, we tested our mobile app for 1 month in participants in a hospital clinic setting. We assessed the app’s usability and acceptability, as well as the patient-doctor relationship, via questionnaires and analysis of app usage data. ResultsWe recruited 30 individuals (18 male and 12 female) for the study. The median number of log-ins per day was 1.21, with the most frequently requested item being setting goals, followed by track physical activities and view personal health status. Scales of the depth of the patient-doctor relationship decreased from 27.6 (SD 4.8) to 25.1 (SD 4.5) by a Wilcoxon signed rank test (P=.02). ConclusionsA mobile phone app linked with an accelerometer for a clinic-based weight loss program is useful and acceptable for weight management but exhibited less favorable early effects on patient-doctor relationships.

Polymer composites with a high electrical conductivity (σ) to thermal conductivity (k) ratio have been intensively investigated in recent years. While highly conductive materials, such as metallic fillers or conducting polymers, were used to enhance σ, microstructural engineering was used to decrease k by forming porous structures, such as aerogels or 3D networks. These structures, however, were mechanically vulnerable and could only have limited applications. In this study, multiwalled carbon nanotube /silicone composites with a high σ/k ratio were developed by forming a double-segregated multiwalled carbon nanotube network in the porous body of the composites. The unique microstructure of the composites was created by a novel fabrication process: layer-by-layer deposition with in-situ polymerization of silicone emulsion particles dispersed in a water solvent. This novel process yielded very thick films, >200 µm, with high σ/k values, ∼2 × 104 (S/m)/(W/m·K). These high σ/k composites can be used for various applications, such as resistive heating elements, thermoelectric materials, and wearable thermotherapy. [ABSTRACT FROM AUTHOR]

In the square-wave voltage signal injection sensorless drive of the interior permanent-magnet synchronous machine, the injection voltage can be distorted by the inverter nonlinearity effects especially when the injection voltage is low. If that happens, a high-frequency (HF) current signal which contains the rotor position information could be also distorted, which directly leads to an error in the position estimation. This paper analyzes the effects of the inverter nonlinearity on injection voltage, on induced current ripple, and on the position estimation performance in sequence and proposes a voltage injection method to minimize the impact of the inverter nonlinearity by the regulation of the HF current ripple. By simulations and experiments, the performance of the proposed method has been verified. The experimental results show 19.7% reduction of position estimation error under 15% of rated voltage signal injection without increasing the current ripple at a certain operating condition. Moreover, the performance of position estimation is kept uniform regardless of the loading condition. [ABSTRACT FROM AUTHOR]

Multiwalled nanotube (MWNT)/silicone composites having segregated MWNT network and micro-void structure were developed for wearable thermotherapy application. The nano-composites could be quickly fabricated from instant evaporation of aqueous medium during spray coating process. Fast electric heating behavior (4.8 °C/s) was demonstrated, in comparison with that (1.4 °C/s) of conventional silicone rubber composites having no void. Long-term stability was also verified with thermal aging and thermal cycling tests up to 100 h. [ABSTRACT FROM AUTHOR]

One of the most important applications for superhydrophobic coatings is anti-frosting for safety and energy conservation. Safety concerns are especially critical in cold-climate regions where the daily temperature fluctuation is large. However, superhydrophobic coatings have not been studied in terms of their thermomechanical reliability. In this study, wetting characteristics and stress relaxation behavior were quantitatively investigated with multi-walled carbon nanotube (MWNT)-silicone composite films under thermal cycling conditions. It is concluded that an open structure with numerous nanopores among the fillers, constituting air pockets described as the "Cassie structure," is of great importance not only for developing a film's superhydrophobic nature but also for accommodation of thermal stress that results from a difference in coefficient of thermal expansion between the coating and the substrate. The amount of stress relaxation for a 30 vol% MWNT-silicone composite film with open structure reaches ~80% of the value for its counterpart with a closed structure and no pores. A superhydrophobic MWNT-silicone composite film that can endure over 4000 thermal cycles (-30 °C to room temperature) is fabricated by controlling the composition and microstructure of the composite. In addition, the importance of the size and shape of the nanofillers in delaying nucleation and growth of frost on superhydrophobic coatings is also discussed. [ABSTRACT FROM AUTHOR]

Highly conducting carbon nanotubes (CNTs)/polydimethylsiloxane (PDMS) composite with a low concentration (5.7 vol.%) has been shown to be applicable in a highly controllable electric heating element. Due to a high shear-processing technique for mixing CNTs into an uncured PDMS matrix, the CNT/PDMS composites have a fairly uniform dispersion and no agglomeration of CNTs. The percolation threshold of the prepared CNT/PDMS composite is achieved \sim0.03~vol.\%, which is one of the lowest values previously reported in the literature. The fabricated CNT/PDMS composites can be quickly heated from room temperature to 200^\circC within 30 s by applying a DC voltage of 12 V. In addition, the CNT/PDMS composite show good thermal stability and repeatability during a long-term heating test. Our proposed CNT/PDMS composites could be used as a basis for light-weight and flexible heating-unit applications. [ABSTRACT FROM AUTHOR]

Negative temperature coefficient of resistance of a material can be a disadvantage in high temperature applications, causing a system to be thermally unstable as the temperature increases. We investigate the concept of excluded volume to suppress the negative temperature coefficient of resistance of a multi-walled carbon nanotube/silicone rubber composite. When micro- or nano-silica particles are incorporated to realize the segregated conductive network, the resistance-temperature dependence of the composite is suppressed in both the conductive polymer composite itself and a fuser unit for printers having the carbon nanotube composite as heating layer. It is believed that the effect of mechanical reinforcement and suppression in thermal expansion by the secondary particles are essential for suppressing the temperature dependence of resistance. This investigation on the excluded volume can be interpreted to offer a new perspective on nanomaterial-based thermistor technology. [ABSTRACT FROM AUTHOR]