Percolating Network of Ultrathin Gold Nanowires and Silver Nanowires toward “Invisible” Wearable Sensors for Detecting Emotional Expression and Apexcardiogram

2 nm thin gold nanowires (AuNWs) have extremely high aspect ratio (≈10 000) and are nanoscale soft building blocks; this is different from conventional silver nanowires (AgNWs), which are more rigid. Here, highly sensitive, stretchable, patchable, and transparent strain sensors are fabricated based on the hybrid films of soft/hard networks. They are mechanically stretchable, optically transparent, and electrically conductive and are fabricated using a simple and cost‐effective solution process. The combination of soft and more rigid nanowires enables their use as high‐performance strain sensors with the maximum gauge factor (GF) of ≈236 at low strain (<5%), the highest stretchability of up to 70% strain, and the optical transparency is from 58.7% to 66.7% depending on the amount of the AuNW component. The sensors can detect strain as low as 0.05% and are energy efficient to operate at a voltage as low as 0.1 V. These attributes are difficult to achieve with a single component of either AuNWs or AgNWs. The outstanding sensing performance indicates their potential applications as “invisible” wearable sensors for biometric information collection, as demonstrated in applications for detecting facial expressions, respiration, and apexcardiogram.     

Water content and temperature effect on ultrasonic pulse velocity of concrete

In this paper, water content and temperature effect on the ultrasonic pulse velocity (UPV) of concrete was investigated. A series of tests were performed to examine the relationship between water content and UPV of concrete with different aggregate mixture proportions. Cube test specimens were made of concrete with water-cement ratio of 0.5. The concrete specimens were immersed in water for 90 days to saturate them. To measure the effect of different water contents on UPV, the test specimens were dried gradually to change the amount of water between measurements. This process was repeated until the concrete pieces was completely dried and weight no longer changed. The water content could be changed from about 6 to 0%. Following, another test procedure was conducted to research the relationship between temperature and UPV. To measure the influence of various temperature on UPV, completely dried concrete specimens were firstly cooled to –18°C and gradually heated to +180°C. In these two different procedures, the UPV values corresponding water content and temperature in the relevant ranges were periodically measured. The test results indicate that the increase in both water content and temperature increases almost linearly UPV of concrete. Based on correlation derived from the test data, irrespective of concrete properties a further increase in both water content of 1% and temperature of 10°C increases UPV of average 160 and 34 m/s, respectively. As overall assessment, this study demonstrates that the UPV is a function of both water content and temperature, and the changing of these two parameters has an important influence on ultrasonic pulse velocity of concrete.     

Beyond Bag-of-Words: combining generative and discriminative models for scene categorization

This paper proposes an efficient framework for scene categorization by combining generative model and discriminative model. A state-of-the-art approach for scene categorization is the Bag-of-Words (BoW) framework. However, there exist many categories in scenes. Generally when a new category is considered, the codebook in BoW framework needs to be re-generated, which will involve exhaustive computation. In view of this, this paper tries to address the issue by designing a new framework with good scalability. When an additional category is considered, much lower computational cost is needed while the resulting image signatures are still discriminative. The image signatures for training discriminative model are carefully designed based on the generative model. The soft relevance value of the extracted image signatures are estimated by image signature space modeling and are incorporated in Fuzzy Support Vector Machine (FSVM). The effectiveness of the proposed method is validated on UIUC Scene-15 dataset and NTU-25 dataset, and it is shown to outperform other state-of-the-art approaches for scene categorization.     

RESULTS ON ESTIMATION AND TESTING FOR A UNIT ROOT IN THE NONSTATIONARY AUTOREGRESSIVE MOVING-AVERAGE MODEL

Abstract. We review the limiting distribution theory for Gaussian estimation of the univariate autoregressive moving-average (ARMA) model in the presence of a unit root in the autoregressive (AR) operator, and present the asymptotic distribution of the associated likelihood ratio (LR) test statistic for testing for a unit root in the ARMA model. The finite sample properties of the LR statistic as well as other unit root test procedures for the ARMA model are examined through a limited simulation study. We conclude that, for practical empirical work that relies on standard computations, the LR test procedure generally performs better than other standard procedures in the presence of a substantial moving-average component in the ARMA model.     

Effect of Cathode Designs on Radiation Emission of Compact Diode (CD) Device

A comparative study on the radiation emission such as X-ray yield and efficiency has been carried out in compact diode device. Two different designs of cathode having sharp-edged razor blade (of 0.5 mm thickness with width 2 mm) and a sewing machine needle (of 0.5 mm diameter at tip with length of 39 mm) have been tested for this study. The radiation emission (X-ray yield) was determined by employing two set of PIN diodes at fixed positions. The maximum X-ray yield depends on cathode designs and electrodes separation in few mm. The yield of X-ray is small in the case of sharp-edged razor blade cathode than the sewing machine needle cathode. The X-ray yield, measured by 4π-geometry, shows its dependence on the cathode designs. The maximum X-ray yield is found to be 939.2 ± 65.7 mJ with efficiency of 0.4142 ± 0.0289%. This study indicates that the compact diode device could be optimized to a great extent for optimal X-ray yield by using an appropriate cathode design.     

Development of polymer derived carbon coated monolith for liquid adsorption application by response surface methodology

The preparation of polymer derived activated carbon coated monolith is reported. The response surface methodology based on Box–Behnken design is used to find the optimal condition for synthesis of mesoporous carbon. The dominant parameters identified are the carbonization temperature, concentration, and molecular weight of pore former agent. Typical values for BET surface area are 341 m²/g _carbon and 20 m²/g _{supported carbon} with pores size distribution in the range of 4–400 nm. The highest pore volume obtained is 182.77 mm³/g _{supported carbon}.     

COMBINE HARVESTER INSTRUMENTATION SYSTEM FOR USE IN PRECISION AGRICULTURE

A crop yield and field performance mapping system for New Holland TC-56 rice combine harvester (RCH) for precision agriculture applications has been developed using LabVIEW. A Dewe-2010 PC data acquisition system has been used as a core unit to collect and store the real time field data from different sensors and a differential global positioning system to determine the exact latitude, longitude, and altitude of RCH. Modular software allows programming flexibility in developed hardware. The spatial information has been measured and recorded in real time field testing. Sensors have been calibrated in a laboratory under specific conditions, and excellent measurement linearity has been obtained for most of parameters. The crop and yield performance maps have been obtained in real time from the field tests conducted in Malaysia. These maps will be used in precision agriculture to improve areas of low yield and to improve productivity of rice.     

Behaviour of fibre-reinforced cementitious composite containing high-volume fly ash at elevated temperatures

This research describes the properties of acrylic fibre-reinforced cementitious composite containing high-volume fly ash. In this investigation, the fly ash content (30% and 60%) and the acrylic fibre dosage (0%, 1% and 2%) were varied. Increased content of fly ash in the composite was found to be able to partially compensate the reduction in workability caused by the inclusion of fibres. On the other hand, although the use of fibres had minimal influence on the compressive strength, the fibres could significantly enhance the flexural strength of the composite, particularly in the composite containing higher fly ash content. At elevated temperatures, it was found that the inclusion of acrylic fibres was beneficial in the composite with higher fly ash content, as demonstrated by the increased strength retention and reduced spalling damage at elevated temperature.     

Dynamic simulation and control of a paper machine wet end

A good simulation model for paper machines can be used to identify deficiencies in the design, bottlenecks during operation, and regions of poor control. It also allows users to test their hypotheses and innovations without potentially causing major upsets and reducing throughput. In this work, a dynamic model of the wet end system has been developed using the IDEAS^TM platform, describing the distribution of fines, fillers and fibres throughout the system. The model was then tested at steady state with mill data for the low‐ash and high‐ash production grades, and the results show that over 70% of the predicted values had only 5% deviation. The dynamic simulation was also used to show that the retention aid controller would react in the wrong direction due to changes in the wire pit consistency and the stock ratio would cause major changes in stream compositions and consistencies of the wet end.