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Advances in imaging-assisted sensing techniques for heavy metals in water: Trends, challenges, and opportunities
No full textHeavy metal pollution of water resources is of worldwide concern, stimulating the development of breakthroughs in detection and remedy technologies. In the digital age, imaging solutions have been applied to almost every sector of civil society, from health and manufacturing to diagnostics, defense, and personal security. The next generation of monitoring sensors and systems for water quality and pollutants is developing at a rapid pace. The present review discusses various aspects of imaging-assisted quantification of heavy metals in water, including transduction techniques (colorimetric and photoluminescence), sensor materials (organic linkers, metal nanoparticles, carbonaceous & semiconductor quantum dots, etc.), the roles of equipment and readout tools (color charts, image scanners, digital cameras, mobile phones, etc.), substrates (organic and inorganic), and sampling methods. To the best of our knowledge, no such efforts have been made previously to critically and comprehensively analyze various aspects on the new imaging-based technologies in the environmental sector
Development of SrFe12O19/Ti3SiC2 Composites for Enhanced Microwave Absorption
No full textMicrowave absorbing composites containing strontium hexaferrite and titanium silicon carbide, SrFe12O19/Ti3SiC2 powder, were synthesized by mixing in different weight ratios. The strontium hexaferrite (SrFe12O19) particles were synthesized using low-temperature combustion. The ‘as synthesized’ strontium hexaferrite powder is observed to have low coercivity (255.09 G) and high saturation magnetization (45.1 emu/g). The titanium silicon carbide (Ti3SiC2) powder was synthesized by heat treatment of the precursors (Ti/Si/TiC) at 1100°C under argon atmosphere. A microwave absorbing composite is fabricated by mixing in a high-energy ball mill followed by heating of SrFe12O19 and Ti3SiC2 powders at 200°C. The maximum reflection loss of − 39.67 dB is observed at 9.46 GHz for the composite casted into pellets containing 20% Ti3SiC2 and 80% SrFe12O19 with 2-mm thickness. The bandwidth for less than − 10 dB loss is observed to be 2.77 GHz (66% of the total band). The developed magneto-dielectric composition confirmed its candidacy as a potential microwave absorbing material
Real time estimation and suppression of hand tremor for surgical robotic applications
No full textIn this work, an algorithm was developed to record and suppress the physiological tremor present in the hands of surgeon doing robotic surgical procedure due to fatigue or otherwise. A prototype setup of master handle having six degree of freedom with a vibration motor was designed and fabricated to record the hand tremor. The work involved recording the composite simulated motion consisting of both voluntary motion of surgeon’s hand and associated involuntary motion of tremor in real time, determination of peak frequencies of both the motions and providing necessary information on the graphical user interface. The adaptive algorithm is capable to cancel out the involuntary motion from the recorded raw signal in real time. After filtration, only voluntary motion remains for further processing. The developed algorithm promises potential to make robotic surgery more precise and error free
Mathematical and simulation analysis of natural convection heat transfer for DC–DC converter
No full textThermal management of electronic systems is the utmost concern to achieve optimum efficiency under space and weight constraints. For the optimal functioning of a system, the heat generated by the electronic components needs to be dissipated efficiently. The passive cooling technique is extensively used in electronic systems, wherein the more contact surface area of a heat source and the surroundings are utilized. This paper focuses on mathematical and simulation analysis for different types of heat sink designs for the 30 W multi-output DC–DC converter. Heat sink with inverted trapezoidal fins has resulted in efficient thermal management of the converter at its safe operating temperature of 398 K. Results show that the maximum temperature attained by the converter was 352 K which was in the safe operating zone of the converter. A comparative study of the effectiveness of heat dissipation with respect to maximum temperature attained has been discussed. Mathematical verification of Rayleigh number for different heat sink designs has also been carried out for its critical value
Label-free fluorescence “turn-on” detection of SO32− by gold nanoclusters: integration in a hydrogel platform and intracellular detection
No full textA facile approach for the fluorescence based detection of sulfite (SO32−) using gold nanoclusters (Au NCs) has been reported. The detection assay relies on the effective quenching of the fluorescence of Au NCs in the presence of Cu2+, which could eventually be recovered upon the addition of SO32−. The proposed Cu2+ assisted fluorescence “turn-on” detection method for SO32− was highly sensitive and demonstrated a linear response towards SO32− within the desired concentration range. Importantly, the sensing system possessed high selectivity for SO32− compared to other competitive anionic analytes, allowing for an analytically robust and reliable detection. Further, fluorescent Au NC-hydrogels were developed, which present a way forward for solid sensing platforms for the detection of SO32− in aqueous solutions, making it a meaningful approach for instrument-free and visual monitoring. Owing to their excellent analytical characteristics, Au NCs were successfully employed for intracellular SO32− detection. Therefore, the present study encompasses the manifold detection aspects of Au NC based sensors
Development of glacier mapping in Indian Himalaya: a review of approaches.
Get PDFThe paper reviews the status of glacier mapping with special reference to the Indian Himalaya. The review provides information on various satellite remote sensing data interpretation methods used with special emphasis laid on recent semi-automated algorithms used for glacier and debris-cover mapping, along with their limitations and challenges. Further, the pragmatic solutions on offer are discussed, and the emerging areas of glacier mapping research are highlighted. The review also touches – contribution of Survey of India (SOI) and Geological Survey of India (GSI) in the glacier mapping. Finally, it discusses the wider range of spatial and spectral domains in which remote sensing data helps to inventories glaciers. The review also identifies gaps in using the latest techniques like Unmanned Aerial Vehicles (UAVs) and machine learning algorithms to improvise on the ongoing efforts. At last, the review provides an exhaustive list of references on glacier mapping from the Indian Himalaya as benefit to readers
Engineering carbon quantum dots for enhancing the broadband photoresponse in a silicon process-line compatible photodetector
No full textRealization of heterojunction based broadband photodetectors (ultraviolet to near-infrared) compatible with existing silicon process technology has great promise for advanced optoelectronic applications. In this report, we demonstrate the application of carbon quantum dots (CQDs) synthesized from organic waste via a facile fabrication technique as a potential broadband photodetector in a hybrid (organic–inorganic) heterostructure with Si. The broadband photoresponse is further improved by impregnating the CQDs with reduced graphene oxide (rGO) and silver nanoparticles (AgNPs). The results show that the optimized incorporation of rGO aids in enhancing the photoresponse due to effective carrier transport, whereas AgNPs intensify the optical absorption due to localized surface plasmon resonance. The maximum responsivity and detectivity for the engineered CQDs are found to be around 1 A W−1 and 2 × 1012 Jones, respectively. This work demonstrates an economic, effective and feasible approach to harness natural resources for technological purposes, which can efficiently be adopted with presently available industry scale technologies
Advanced Functional Structure-Based Sensing and Imaging Strategies for Cancer Detection: Possibilities, Opportunities, Challenges, and Prospects
No full textCancer is the second most common cause of death in the world. The principal limitations thus far encountered in the clinical practice of probing cancer are diverse and include low sensitivity, time consumption, bulkiness, and cost. In this respect, nanomaterial (NM)‐based sensing techniques are recognized as a superior alternative to efficiently resolve such limitations. A better understanding of NM‐based sensing platforms is thus important so that these novel avenues can easily be explored for clinical applications. These platforms have the merits of high sensitivity, high specificity, rapid response, and easy‐to‐read signals. This review offers a comprehensive survey of NM‐based advanced cancer‐sensing techniques and will help the scientific community establish optimum sensing strategies based on an accurate assessment of the interactions between cancer biomarkers and NM‐based platforms
Precision machining of biopolymers: A brief review of the literature and case study on diamond turning
No full textNowadays, biomaterials have attained great importance in medical sector owing to the urgent requirement of the material systems which can be suitable for different sorts of human body treatments. Among the various biomaterials available, commercially, polymeric materials occupy great importance because of their near-to-organ characteristics, biocompatibility, corrosion resistance, and other essential mechanical features. The current applications of biopolymers include scaffolding, load-bearing implants, intraocular lenses, artificial heart valves, cardiovascular prostheses, cardiopulmonary bypass, hemodialysis, and dental and orthopedic applications. Although there exist numerous established fabrication routes for biopolymers, yet, their post processing is often required in order to achieve required geometrical and topographical performances. Therefore, machining of the processed biopolymers is often required. The aim of this article was to present a crisp review of the machining of different biopolymers. Further, being an ultraprecision machining operation, specific attention has been paid on the diamond turning technique as well as a case study has been performed to study the effect of process parameters on the resulting characteristics. Overall, the current work will provide a unique platform which could be helpful for young biomedical engineers and scientists focusing on precision surface engineering
Design and development of a field deployable packaged fiber Bragg grating-based accelerometer
No full textExperimental realization of a fiber Bragg grating-based compact, high-sensitive, and fully packaged single-axis accelerometer has been demonstrated. To verify experimentally observed results, simulation has been carried out for the performance comparison of packaged single-axis accelerometer with the cantilever of various materials. The experimental demonstrations have been conducted at unknown seismic vibrations of random frequencies as well as the vibrations of known frequencies. The experimental results for the reported seismic events (i.e., footprint and hammering) demonstrate that the developed fully packaged accelerometer possesses good response to the signals with random vibrations. The developed accelerometer holds a high sensitivity up to 88 pm/g in the broad bandwidth. Such a compact fully packaged accelerometer with improved sensitivity can be deployed at any civil engineering structures, such as highways, bridges, dams, tunnels, pipelines, and aeronautical platforms for broadband dynamic monitoring of the random vibrations ranging from 5 to 100 Hz