Determination of tensile forces to enhance the supply stability of reinforced fiber

The manufacturing process of long fiber thermoplastic is initiated by supplying reinforced fiber wound in a spool dispenser. If problems such as tangling or kinking occur in the apparatus used for supplying the reinforced fiber in the long-fiber thermoplastic direct process, the productivity of the long-fiber thermoplastic decreases. Therefore, it is important to enhance the supply stability of reinforced fiber. In general, the increase in supply stability can be achieved by maintaining a steady balloon shape that is controlled by the unwinding velocity or tensile force of the reinforced fiber. In this research, the range of suitable tensile force was determined under the assumption that the unwinding velocity remained constant. The reinforced fiber was assumed to be inextensible, homogeneous, and isotropic and to have uniform density. The transient-state unwinding equation of motion to analyze the unwinding motion of reinforced fiber can be derived by using Hamilton’s principle for an open system in which mass can change within a control volume. In the process of solving the transient-state unwinding equation of motion, the exact two-point boundary conditions are adopted for each time step.     

A study on the band split of power spectral density for a vibration test

A vibration aging test is a part of equipment qualification. When the vibration level is too high for the shaker system, the equivalent test can be accomplished by bandsplitting and/or time-level trade techniques. This paper discusses the power spectral density (PSD) band-splitting effect on fatigue damage and a method for the application to PSD bandsplitting. Three types of acceleration PSDs—band-limited white noise (BLWN) PSD, unimodal PSD, and bimodal PSD—with various shapes were chosen as target PSDs. Oritz and Chens method, and Benascuitti and Tovo’s method were used to calculate fatigue damage spectra (FDS). The maximum values of fatigue damage ratios for all target PSDs were calculated. It was found that PSD overlapping can be used to compensate for the lack of fatigue damage due to PSD band-splitting. An application example of the suggested method that enables conservative testing when applying PSD band-splitting is presented herein.

     

Real-time measurement of the contractile forces of self-organized cardiomyocytes on hybrid biopolymer microcantilevers

We present a microfabricated hybrid biopolymer microcantilever, in which the contractile force of self-organized cardiomyocytes can be measured and studied, as a prototype for the development of cell-driven actuators. The microcantilever is made of a flexible, transparent, biocompatible poly(dimethylsiloxane) substrate, using a simple microfabrication technique. Seeding and culturing cardiomyocytes on the specific cantilever allows us to perform highly sensitive, quantitative, and noninvasive measurement of the contractile force of the self-organized cells in real time. The motions of the microcantilever showed good agreement with an analytical solution based on Stoney's equation and finite element modeling (FEM) of the hybrid system. Immunostaining of the cells on the hybrid system showed continuous high-order coalignment of actin filaments and parallel sarcomeric organization in the direction of the longitudinal axis of the microcantilever without structural constraints, such as microgrooves or lines, and proved our FEM and the synchronous contraction of cardiomyocytes. The presented device should facilitate measurement of the contractile force of self-organized cardiomyocytes on a specific area, which may help the understanding of heart failure and the design of optimal hybrid biopolymer actuators, as well as assist development of a microscale cell-driven motor system.     

Formational bounds of link prediction in collaboration networks

Scientometrics - With an ever increasing number of academic conferences being offered and a growing concern regarding the appearance of “predatory conferencing”, the optimal use of...     

ORCID-linked labeled data for evaluating author name disambiguation at scale

Scientometrics - How can we evaluate the performance of a disambiguation method implemented on big bibliographic data? This study suggests that the open researcher profile system, ORCID, can be...     

Generating automatically labeled data for author name disambiguation: an iterative clustering method

Scientometrics - To train algorithms for supervised author name disambiguation, many studies have relied on hand-labeled truth data that are very laborious to generate. This paper shows that...     

Microfluidic chip to produce temperature jumps for electrophysiology

We developed a microfluidic chip that provides rapid temperature changes and accurate temperature control of the perfusing solution to facilitate patch-clamp studies. The device consists of a fluid channel connected to an accessible reservoir for cell culture and patch-clamp measurements. A thin-film platinum heater was placed in the flow channel to generate rapid temperature change, and the temperature was monitored using a thin-film resistor. We constructed the thermal chip using SU-8 on a glass wafer to minimize the heat loss. The chip is capable of increasing the solution temperature from bath temperature (20 degrees C) to 80 degrees C at an optimum heating rate of 0.5 degrees C/ms. To demonstrate the ability of the thermal chip, we have conducted on-chip patch-clamp recordings of temperature-sensitive ion channels (TRPV1) transfected HEK293 cells. The heat-stimulated currents were observed using whole-cell and cell-attached patch configurations. The results demonstrated that the chip can provide rapid temperature jumps at the resolution of single-ion channels.     

Physiological parameter monitoring from optical recordings with a mobile phone

We show that a mobile phone can serve as an accurate monitor for several physiological variables, based on its ability to record and analyze the varying color signals of a fingertip placed in contact with its optical sensor. We confirm the accuracy of measurements of breathing rate, cardiac R-R intervals, and blood oxygen saturation, by comparisons to standard methods for making such measurements (respiration belts, ECGs, and pulse-oximeters, respectively). Measurement of respiratory rate uses a previously reported algorithm developed for use with a pulse-oximeter, based on amplitude and frequency modulation sequences within the light signal. We note that this technology can also be used with recently developed algorithms for detection of atrial fibrillation or blood loss.     

All-digital TX frequency synthesizer and discrete-time receiver for Bluetooth radio in 130-nm CMOS

We present a single-chip fully compliant Bluetooth radio fabricated in a digital 130-nm CMOS process. The transceiver is architectured from the ground up to be compatible with digital deep-submicron CMOS processes and be readily integrated with a digital baseband and application processor. The conventional RF frequency synthesizer architecture, based on the voltage-controlled oscillator and the phase/frequency detector and charge-pump combination, has been replaced with a digitally controlled oscillator and a time-to-digital converter, respectively. The transmitter architecture takes advantage of the wideband frequency modulation capability of the all-digital phase-locked loop with built-in automatic compensation to ensure modulation accuracy. The receiver employs a discrete-time architecture in which the RF signal is directly sampled and processed using analog and digital signal processing techniques. The complete chip also integrates power management functions and a digital baseband processor. Application of the presented ideas has resulted in significant area and power savings while producing structures that are amenable to migration to more advanced deep-submicron processes, as they become available. The entire IC occupies 10 mm/sup 2/ and consumes 28 mA during transmit and 41 mA during receive at 1.5-V supply.