Inkjet Process for Conductive Patterning on Textiles: Maintaining Inherent Stretchability and Breathability in Knit Structures

In this work, a novel technique of inkjet printing e‐textiles with particle free reactive silver inks on knit structures is developed. The inkjet‐printed e‐textiles are highly conductive, with a sheet resistance of 0.09 Ω sq^‐1, by means of controlling the number of print passes, annealing process, and textile structures. It is notable that the inkjet process allows textiles to maintain its inherent properties, including stretchability, flexibility, breathability, and fabric hand after printing process. This is achieved by formation of ultrathin silver layers surrounding individual fibers. The silver layers coated on fibers range from 250 nm to 2.5 µm, maintaining the size of interstices and flexibility of fibers. The annealing process, structure of fibers, and printed layers significantly influence the electrical conductivity of the patterned structures on textiles. Outstanding electrical conductivity and durability are demonstrated by optimizing print passes, controlling textile structures, and incorporating an in situ annealing process. The electrical resistance dependence on the strain rate of the textiles is examined, showing the ability to maintain electrical conductivity to retain light‐emitting diode use, stable more than 500 consecutive strain cycles. Most importantly, inkjet‐printed e‐textiles maintain their characteristic washability, breathability, and fabric hands for applications in wearable technology.     

Software dependability in the Tandem GUARDIAN system

Based on extensive field failure data for Tandem's GUARDIAN operating system, the paper discusses evaluation of the dependability of operational software. Software faults considered are major defects that result in processor failures and invoke backup processes to take over. The paper categorizes the underlying causes of software failures and evaluates the effectiveness of the process pair technique in tolerating software faults. A model to describe the impact of software faults on the reliability of an overall system is proposed. The model is used to evaluate the significance of key factors that determine software dependability and to identify areas for improvement. An analysis of the data shows that about 77% of processor failures that are initially considered due to software are confirmed as software problems. The analysis shows that the use of process pairs to provide checkpointing and restart (originally intended for tolerating hardware faults) allows the system to tolerate about 75% of reported software faults that result in processor failures. The loose coupling between processors, which results in the backup execution (the processor state and the sequence of events) being different from the original execution, is a major reason for the measured software fault tolerance. Over two-thirds (72%) of measured software failures are recurrences of previously reported faults. Modeling, based on the data, shows that, in addition to reducing the number of software faults, software dependability can be enhanced by reducing the recurrence rate     

Effects of Bleaching on the Properties of Roasted Sesame Oil

ABSTRACT: Improvement in quality of roasted sesame oil was studied. Roasted sesame oil was bleached at 70 °C, 85 °C, or 100 °C for 20 min with acid-activated clay at 0.5%, 1.0%, or 3.0% (w/w) and then centrifuging at 12096 × g at 4 °C for 10 min. The color of the roasted sesame oil became lighter and the viscosity of oil decreased by bleaching. Bleaching caused a significant increase in the smoke point of the oil, from 170 °C to a range of 183 °C to 191 °C. Bleaching increased palmitic acid and decreased linoleic acid contents of roasted sesame oil. Bleaching decreased free fatty acid (FFA) and conjugated dienoic acid (CDA) contents and carbonyl values (CV) of roasted sesame oil. The more the acid clay was used, the lower were the FFA and CDA contents and CV of the oil. Amount of acid clay in bleaching of roasted sesame oil had higher effects on the color, viscosity, smoke point, FFA and CDA contents, and CV of roasted sesame oil than the bleaching temperature. Bleaching did not show a significant effect on tocopherol contents of the sesame oil. Bleaching tended to decrease sesamolin contents and increase sesamol contents in the roasted sesame oil. As the amount of acid clay and the bleaching temperature increased, the contents of sesamin and sesamolin in the oil decreased while sesamol contents increased.     

Quantitative analysis on the depletion rate of β-NiAl phases in MCrAlY coating

In this study, a disk-shaped thermal barrier coating system for a gas turbine blade was isothermally aged at 1100°C for various times up to 800 h. The microstructures of the bond coat were observed by using an optical microscope for each aging condition. Diffusion of primary elements consisting of the bond coat was characterized by using electron probe microanalyzer mapping. Semi-quantitative analysis by using scanning electron microscopy energy-dispersive X-ray was insufficient to sense variations in the Al content within the bond coat according to exposure time. An area fraction of β-NiAl phases within the bond coat was calculated by image analysis, and a reasonable approach to estimate time for complete depletion of the Al-rich β-NiAl phase within the bond coat was suggested.     

Additive manufacturing of smart insole by direct printing of pressure sensitive material

3D printing technology is gaining attention as one of the key technologies that will lead the fourth industrial revolution. In addition, the field of application is from trial production to mass production of products. However, in many cases, the application area is limited to the geometrical shape building of products. This paper shows an example of application technology for manufacturing the smart insole by applying 3D printing technology for the purpose of giving various functions as well as making geometric shape. In the production of smart insole, 3D printing technology is applied to direct printing of pressure sensitive sensor and highly conductive wire as well as flexible insole object itself. The materials used in the production of flexible products, conductors and sensor are different, and in order to produce the sensor by 3D printing, suitable materials have been directly manufactured and used. This paper shows that the 3D printing technology can be directly applied to the manufacturing of multi functional products through the above manufacturing process as well as the experimental results after the actual production.

     

Finite element analysis for temperature distributions in a cold forging

In this research, the finite element method is utilized to predict the temperature distributions in a cold-forging process for a cambolt. The cambolt is mainly used as a part of a suspension system of a vehicle. The cambolt has an off-centered lobe that manipulates the vertical position of the knuckle and wheel to a slight degree. The cambolt requires certain mechanical properties, such as strength and endurance limits. Moreover, temperature is also an important factor to realize mass production and improve efficiency. However, direct measurement of temperature in a forging process is infeasible with existing technology; therefore, there is a critical need for a new technique. Accordingly, in this study, a thermo-coupled finite element method is developed for predicting the temperature distribution. The rate of energy conversion to heat for the workpiece material is determined, and the temperature distribution is analyzed throughout the forging process for a cambolt. The temperatures associated with different punch speeds are also studied, as well as the relationships between load, temperature, and punch speed. Experimental verification of the technique is presented.     

Simulation of meshing for the spur gear drive with modified tooth surfaces

The authors have proposed methods (lead crowning and profile modification) for modifying the geometry of spur gears and investigated the contact pattern as well as the transmission errors to recommend the appropriate amount of modification. Based on the investigation, dynamic load of the modified spur gear drive has been calculated, which is helpful to predict the life of the designed gear drive. Computer programs for simulation of meshing, contact and dynamics of the modified spur gears have been developed. The developed theory is illustrated with numerical examples.     

Dynamics in carom and three cushion billiards

This paper presents the analysis results of dynamics in the billiards game within the framework of rigid-body mechanics and a numerical simulation program. The friction exists between the ball and the table bed as well as between the ball and the rail. There are three parts in the dynamic behavior of the ball on the table bed; motion of the ball on the table bed, collision between balls, and collision between the ball and the cushion. During the development of the simulation program, the dynamics problems such as rolling motion and three-dimensional frictional impact motion have been analyzed in detail. The theoretical issues are implemented into a viable graphic simulation program and its efficacy is demonstrated through the experimental validation of the billiards game. The resulting analysis results are verified quantitatively and qualitatively using high-speed video camera. Through the experimental tests, it was found that the physical parameters such as coefficients of restitution and friction vary according to the motion variables and corresponding empirical formulations were developed. The simulation and experimental results agree well.     

Synthesis and characterization of fluorosulfonyl imide isatin biphenylene block copolymer for PEMFC

In this study, A fluorosulfonyl imide-containing precursor derived from fluorosulfonyl isocyanate was synthesized and grafted on poly (isatin-biphenylene) random and block copolymers. The carbon-carbon structured poly (isatin biphenylene)s were prepared by super acid catalyzed polyhydroxyalkylation reaction with istain, 2,2′-biphenyl, 2,2′-dihydroxybiphenyl. A fluorosulfonyl imide-containing precursor was prepared from chlorosulfuric acid and fluorosulfonylisocyanate. Fluorosulfonyl imide group have higher acidity than sulfonic acid group, therefore the membranes containing fluorosulfonyl imide groups instead of sulfonic acid groups were studied. These membranes showed slightly higher performance of proton conductivity, low water uptake, and good dimensional stability. The structure of the synthesized polymer was investigated by ¹H NMR spectroscopy. Surface morphologies will also be assessed by atomic force microscope (AFM). Microphase-separated block copolymers are preferred over random copolymers.     

OPTIMUS:online persistent tracking and identification of many users for smart spaces

A smart space, which is embedded with networked sensors and smart devices, can provide various useful services to its users. For the success of a smart space, the problem of tracking and identification of smart space users is of paramount importance. We propose a system, called Optimus, for persistent tracking and identification of users in a smart space, which is equipped with a camera network. We assume that each user carries a smartphone in a smart space. A camera network is used to solve the problem of tracking multiple users in a smart space and information from smartphones is used to identify tracks. For robust tracking, we first detect human subjects from images using a head detection algorithm based on histograms of oriented gradients. Then, human detections are combined to form tracklets and delayed track-level association is used to combine tracklets to build longer trajectories of users. Last, accelerometers in smartphones are used to disambiguate identities of trajectories. By linking identified trajectories, we show that the average length of a track can be lengthened by over six times. The performance of the proposed system is evaluated extensively in realistic scenarios.