The effect of heat treatments on the properties of Ti/Pt heating elements for gas sensor applications

Ti/Pt as heating element for gas sensor applications was fabricated on silicon (Si) wafer substrate. The fabricated device was subjected to heat treatment at different prescribed time periods for thermal stability. The energy dispersion spectroscopy (EDS) results of the device indicated that there were no Ti traces on the Pt surface after heat treatment at 450 °C for 3 and 4 h in an argon (Ar) atmosphere. A maximum temperature coefficient of resistance (TCR) with a value of 2.88×10^?3 K^?1 was obtained for the device with 3 h heat treatment.     

Ag Nanowire Reinforced Highly Stretchable Conductive Fibers for Wearable Electronics

Stretchable conductive fibers have received significant attention due to their possibility of being utilized in wearable and foldable electronics. Here, highly stretchable conductive fiber composed of silver nanowires (AgNWs) and silver nanoparticles (AgNPs) embedded in a styrene–butadiene–styrene (SBS) elastomeric matrix is fabricated. An AgNW‐embedded SBS fiber is fabricated by a simple wet spinning method. Then, the AgNPs are formed on both the surface and inner region of the AgNW‐embedded fiber via repeated cycles of silver precursor absorption and reduction processes. The AgNW‐embedded conductive fiber exhibits superior initial electrical conductivity (σ₀ = 2450 S cm^?1) and elongation at break (900% strain) due to the high weight percentage of the conductive fillers and the use of a highly stretchable SBS elastomer matrix. During the stretching, the embedded AgNWs act as conducting bridges between AgNPs, resulting in the preservation of electrical conductivity under high strain (the rate of conductivity degradation, σ/σ₀ = 4.4% at 100% strain). The AgNW‐embedded conductive fibers show the strain‐sensing behavior with a broad range of applied tensile strain. The AgNW reinforced highly stretchable conductive fibers can be embedded into a smart glove for detecting sign language by integrating five composite fibers in the glove, which can successfully perceive human motions.     

Ultra Low Power Improved Differential Amplifier

In this paper, a low voltage and ultra low power operational transconductance amplifier (OTA) is presented. As will be shown, the transient response and open loop gain of the proposed OTA are improved using adaptive biasing and DC gain enhancement techniques. The contributions of the proposed OTA are ultra low power consumption (only 3.977 μw), low supply voltages (±0.6 V), high swing, high speed, and high gain. It can clearly be seen that for the proposed OTA, the gain of the differential half-circuit in the input stage (A _d ), DC gain (A ₀), gain bandwidth (GBW), and slew rate (SR) are increased, whereas the settling time (T _S ) is decreased. The results of simulations done using 0.18 μm Silterra CMOS process technology and the measurement results are presented to validate and compare the advantages of this work and other related works.     

A Zero-Pole Reposition Based, 0.95-mW, 68-dB,Linear-in-dB,Constant-Bandwidth Variable Gain Amplifier

A variable-gain amplifier with very low power consumption and wide tuning range is presented. The operational principle of this unique structure is discussed, its most important formulas are derived and its outstanding performance is verified by simulation in TSMC 0.18-μm N-well CMOS fabrication process. Owing to the novel zero-pole repositioning technique, the proposed circuit demonstrates very high frequency bandwidth of 79 MHz while drawing only 0.52 mA from 1.8 V power supply. The interesting results such as a very small core area of about 0.0025 mm² as well as a wide linear-in-dB and constant-bandwidth tuning range of 68.2 dB along with a very low power consumption of 0.95 mW are achieved utilizing standard CMOS technology. The stability of the proposed VGA is verified through transient sinusoidal response analysis. Full process, voltage and temperature (PVT) variation analysis of the circuit is also investigated through Monte Carlo and corner case analysis in order to approve the robustness of the structure. Monte Carlo simulations show standard deviation values of 4.6 dB and 78.3 MHz in gain and gain-bandwidth product, respectively. These results show that our zero-pole repositioning method would lend itself well for use in low-power and high-frequency applications, especially in high-speed automatic gain control amplifiers.     

Mechatronic Design Quotient as the Basis of a New Multicriteria Mechatronic Design Methodology

A concurrent, integrated, and multicriteria methodology is presented for the conceptual design of mechatronic systems. It uses an evaluation model called mechatronic design quotient (MDQ) to facilitate decision-making in the design process. A nonlinear fuzzy integral is used for the aggregation of criteria in MDQ, thereby accommodating possible correlations among them. The performance of the developed methodology is validated by applying it to an industrial fish cutting machine called Iron Butcher-an electromechanical system that falls into the class of mixed or multidomain systems     

Sink-oriented tree based data dissemination protocol for mobile sinks wireless sensor networks

Wireless Networks - Data dissemination toward static sinks causes the nearby nodes to deplete their energy quicker than the other nodes in the field (i.e., this is referred to as the hotspot...     

A design paradigm for mechatronic systems

Concepts of mechatronics are applicable in the design of complex and multi-domain dynamic systems. This paper presents an approach based on the mechatronic design quotient (MDQ) for systematic design of a mechatronic system. Traditional procedures of design are hierarchically separated into topological design and parametric design. Extending this concept, an MDQ may be “structured” into a multi-layered hierarchy. The approach and significance of the application of MDQ in mechatronic design are indicated using illustrative examples.     

Fabrication of porous ZnO via electrochemical etching using 10 wt% potassium hydroxide solution

We described the fabrication of porous ZnO using the electrochemical etching method. ZnO thin films deposited by radiofrequency sputtering were etched electrochemically using 10 wt% KOH solution as an etching medium to obtain porous ZnO surface structure. A constant voltage of 15 V was applied to enhance the etching process. The etched samples were then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy to examine their structural and optical properties. XRD spectra showed that by performing the electrochemical etching process, porous ZnO could be obtained without severely deteriorating the crystallinity of the samples. Moreover, SEM characterization revealed that hillock-type porous ZnO was fabricated successfully. In addition, the cross-sectional SEM images revealed that there were only minimal changes in the layer thickness after the ZnO had been etched for various lengths of time. This finding shows the dominance of the vertical etching process. Notably, the intensity of PL spectra increased and the PL excitation peak exhibited a red shift trend as the etching time increased. These observations are due to the increase of the surface to volume ratio of the ZnO surface and the strain relaxation along the dislocation and grain boundary.     

A translinear principle based low-power high-precision RMS-to-DC converter in CMOS technology

Analog Integrated Circuits and Signal Processing - In the present study, a low-power high-precision current-mode CMOS true root mean square (RMS)-to-DC converter is presented based on the...     

Enhancement of Return Routability Mechanism for Optimized‐NEMO Using Correspondent Firewall

Network Mobility (NEMO) handles mobility of multiple nodes in an aggregate manner as a mobile network. The standard NEMO suffers from a number of limitations, such as inefficient routing and increased handoff latency. Most previous studies attempting to solve such problems have imposed an extra signaling load and/or modified the functionalities of the main entities. In this paper, we propose a more secure and lightweight route optimization (RO) mechanism based on exploiting the firewall in performing the RO services on behalf of the correspondent nodes (CNs). The proposed mechanism provides secure communications by making an authorized decision about the mobile router (MR) home of address, MR care of address, and the complete mobile network prefixes underneath the MR. In addition, it reduces the total signaling required for NEMO handoffs, especially when the number of mobile network nodes and/or CNs is increased. Moreover, our proposed mechanism can be easily deployed without modifying the mobility protocol stack of CNs. A thorough analytical model and network simulator (Ns‐2) are used for evaluating the performance of the proposed mechanism compared with NEMO basic support protocol and state‐of‐the‐art RO schemes. Numerical and simulation results demonstrate that our proposed mechanism outperforms other RO schemes in terms of handoff latency and total signaling load on wired and wireless links.