Silicon doped SnO2 films for liquid petroleum gas sensor

Silicon doped SnO₂ films were synthesized by sputtering SnO₂ layer onto glass substrates with appropriate amount of silicon sputtered onto them. The bilayer structures were subjected to rapid thermal annealing for the incorporation of Si in SnO₂ matrix. The films thus obtained were characterized by measuring optical and microstructural properties. Liquid petroleum gas (LPG) sensing properties were also investigated. FTIR and Raman studies were also carried out on these films, both, before and after LPG exposure.     

Effects of adsorbent dose, its particle size and initial arsenic concentration on the removal of arsenic, iron and manganese from simulated ground water by Fe3+ impregnated activated carbon

This paper presents the observations of the study on arsenic removal from a contaminated ground water (simulated) by adsorption onto Fe³⁺ impregnated granular activated carbon (GAC-Fe). Fe²⁺, Fe³⁺ and Mn²⁺ have also been considered along with arsenic species in the water sample. Similar study has also been done with untreated granular activated carbon (GAC) for comparison. The effects of adsorbent dose, particle size of adsorbent and initial arsenic concentration on the removal of As(T), As(III), As(V), Fe²⁺, Fe³⁺ and Mn²⁺ have been discussed. Under the experimental conditions, the optimum adsorbent doses for GAC-Fe and GAC have been found to be 8 g/l and 24 g/l, respectively with an agitation time of 15 h. Particle size of the adsorbents (both GAC and GAC-Fe) has shown negligible effect on the removal of arsenic and Fe species. However, for Mn removal the effect of adsorbent particle size is comparatively more. Percentage removal of As(T), As(V) and As(III) increase with the decrease in initial arsenic concentration (As₀). However, the increase in percentage removal of all the arsenic species with decrease in As₀ are less for higher value of As₀ (3000–500 ppb) than those of the lower value of As₀ (500–10 ppb). The % removal of As(T), As(III), As(V), Fe, and Mn were 95%, 92.4%, 97.6%, 99% and 41.2%, respectively when 8 g/l GAC-Fe was used at the As₀ value of 200 ppb. However, for GAC these values were 55.5%, 44%, 71%, 98% and 97%. The pH and temperature of the study were 7 ± 0.1 and 30 ± 1 °C, respectively.     

Mathematical modelling of toxicity-related trade-offs in metronomic chemotherapy

For better quality of life (QoL) for the cancer patients, metronomic chemotherapy (MCT) would be the rational option instead of conventional chemotherapy. However, in view of the recent arguments regarding the accumulation of toxicity in MCT, it is worthwhile to examine the role of pathophysiological constraints in retarding the curative potential of MCT. Drug application is stopped upon attaining a certain high level of toxicity and subsequent resumption is possible once the toxicity drops below a certain low level. Large delays in subsequent drug administration can thus effectively handle toxicity and it may retard the therapeutic potential due to excessive tumour growth in the absence of drug. Small delays, on the other hand, may result in inoperable pathophysiological states resulting in poor QoL. It is argued that only the intervention of domain knowledge of an expert oncologist with respect to drug administration decision can in fact clinch the trade-off issues arising out of the situation in favour of a sustainable QoL. A mathematical model that may act as a general guideline to tackle the trade-off issues in cancer treatment is provided. Rigorous simulation exercises are required to establish the concept of MCT in the backdrop of conventional cancer treatment practices.     

Estimating weak ratiometric signals in imaging data. I. Dual-channel data

Ratiometric fluorescent indicators are becoming increasingly prevalent in many areas of biology. They are used for making quantitative measurements of intracellular free calcium both in vitro and in vivo, as well as measuring membrane potentials, pH, and other important physiological variables of interest to researchers in many subfields. Often, functional changes in the fluorescent yield of ratiometric indicators are small, and the signal-to-noise ratio (SNR) is of order unity or less. In particular, variability in the denominator of the ratio can lead to very poor ratio estimates. We present a statistical optimization method for objectively detecting and estimating ratiometric signals in dual-wavelength measurements of fluorescent, ratiometric indicators that improves on standard methods. With the use of an appropriate statistical model for ratiometric signals and by taking the pixel-pixel covariance of an imaging dataset into account, we are able to extract user-independent spatiotemporal information that retains high resolution in both space and time.     

Tunnel FET-based ultralow-power and hardware-secure circuit design considering p-i-n forward leakage

Tunnel field-effect transistor (TFET) exhibits significant p-i-n forward leakage with the increase in drain-to-source voltage bias, and this adversely impacts the power consumption and reliability of TFET digital circuits. This work presents low-power circuit techniques that result in novel compact gates and recommends tristate gates to mitigate the leakage effects. The proposed novel compact gates and tristate gates demonstrate two and six times lower power consumption compared with conventional TFET transmission gates with enhanced reliability. Further, this work introduces a new design methodology that leverages TFET p-i-n forward leakage for hardware obfuscation applications. Utilizing the proposed design methodology, the optimization of 40% and 80% in area and power consumption of hardware security primitives like true random number generators is also accomplished.     

Robust low-order controller design for multi-modal power oscillation damping using flexible AC transmission systems devices

Damping of multi-modal oscillation through supplementary control of a single flexible AC transmission system (FACTS) device is illustrated here. This often requires multiple feedback signals in a centralised multi-input single-output framework for which extension of the classical control design approaches is not straight forward. Past contributions have either focused on decentralised design of low-order PSS in an SISO or MIMO framework; or alternatively, on robust control design techniques which of course, result in higher order controllers. An attempt to design a fixed (low)-order controller, which is robust and is able to damp multiple swing modes with a single FACTS device is presented. The control design problem is formulated as a multi-objective parameter optimisation and solved using a standard evolutionary optimisation technique. Possible post-contingency operating conditions are considered explicitly during the design phase itself to reduce the conservativeness. The present exercise is a step forward towards use of wide area measurement systems for closed-loop supplementary control (around the primary voltage and/or power flow control loop) of the FACTS devices to improve the transfer capacity of the existing corridors.     

Surface plasmon characteristics of nanocrystalline gold/DLC composite films prepared by plasma CVD technique

Composite films containing gold nanoparticles embedded in diamond-like carbon (Au–DLC) matrix were deposited on glass and Si (1 0 0) substrates by using capacitatively coupled plasma (CCP) chemical vapour deposition technique (CVD). Particle size and metal volume fraction varied between 2.7–3.5 nm and 0.04–0.7, respectively with the amount of argon in the methane + argon gas mixture in the plasma. Bonding environment in these films were obtained from XPS, Raman and FTIR studies. Microstructural studies were carried out by SEM, XRD and TEM studies. Blue-shift of the surface plasmon resonance peak (located 540–561 nm) in the optical absorbance spectra of the films could be associated with the reduction of the particle size while red shift was associated with the increase in volume fraction of metal particles. The experimental results have been discussed in light of the core–shell model.     

Electrophoretic deposition of CuO particulate thick film for ethanol sensing

Journal of Materials Science: Materials in Electronics - Detection of volatile organic compounds is of utmost importance in numerous applications such as medical diagnosis, air quality monitoring,...     

Robust congestion control in cognitive radio network using dynamic event‐triggered sliding mode

The ever‐increasing service demand from wireless users under restricted bandwidth necessitates the development of suitable congestion control scheme for throughput maximization. A robust congestion controller design has been addressed in this work to sustain necessary Quality of Service in Cognitive Radio Network. The goal is to reduce packet loss while ensuring optimum utilization of available resources. Sliding mode controller proclaimed for its disturbance rejection capabilities and robustness has been used to design the proposed controller. Using the benefits of sliding mode control, dynamic event‐triggering strategies have been combined for better utilization in resource‐constrained environments. Control execution requires minimal updates while guaranteeing the desired closed‐loop system behavior. The controller efficacy has been validated in simulations.