Real time estimation and suppression of hand tremor for surgical robotic applications

In 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

Development of SrFe12O19/Ti3SiC2 Composites for Enhanced Microwave Absorption

Microwave 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

Advances in imaging-assisted sensing techniques for heavy metals in water: Trends, challenges, and opportunities

Heavy 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

Mathematical and simulation analysis of natural convection heat transfer for DC–DC converter

Thermal 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

Climate change drives glacier retreat in Bhaga basin located in Himachal Pradesh, India

This paper reports changes in different glaciers of Bhaga basin located in western Himalaya, from 1979 to 2017. Glacier boundaries were delineated through semi-automated approach using Landsat satellite imagery. The variation of glacier extent in different elevation zones, snout retreat and decadal changes are observed. Results show that the total area of glaciers was 238 km2 in 1979, which reduced to 230.8 km2 by 2017 (retreat rate 12 m yr−1). Glaciers at low elevation and smaller in size are retreating faster. Analysis of Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation data shows decreasing trend of annual precipitation (–2.724 mm yr−1, 1951–2015 and increasing trend of mean annual temperature (0.021° C yr−1). The statistical analysis using Mann-Kendall and Sen’s slope tests, applied at different confidence interval demonstrates that climate change corresponds to deglaciation, and topography controls glacier recession in the basin

Impact on optical, electrical and antibacterial response of microwave irradiated silver nanoparticles

Silve spectroscopy, Fourier transform infrared spectroscopy (FTIR), photoluminescence, Raman spectroscopy, X-ray powder diffraction (XRD), scanning and transmission electron microscopy (SEM–TEM), zeta potential and dynamic light scattering (DLS). The presence of surface plasmon resonance (SPR) band (416 nm) confirmed fabrication of AgNPs. The effect of microwave irradiation time showed that the size, shape and stability of AgNPs depend on increasing of peak intensity with increasing reaction time. FTIR spectrum confirmed the possible functional group in the product indicating presence of PVP. The enlargement in the size and agglomeration of nanoparticles were prevented by r nanoparticles (AgNPs) have been formulated using microwave irradiation from non-aqueous solution of silver nitrate (AgNO3) and poly (N-vinyl-2-pyrrolidone) (PVP) as a stabilizer. Ethanol has also been reacted like a reducer for microwave irradiation process which is quite rapid, homogeneous and efficient. The as synthesized AgNPs was further characterized by ultraviolet–Visible (UV–Vis)encapsulation of PVP during the reaction. XRD spectra illustrated that AgNPs are higher crystalline having face-centered cubic surface. The morphological analysis found that the AgNPs are homogeneous and spherical with the size of 18 ± 5 nm. The zeta potential measurement affirms the higher stability of AgNPs due to its negatively charged surface. The prepared AgNPs also exhibited electrical properties obeying the ohm’s law and significantly antimicrobial activities against Escherichia coli due to the small size

Surface Modification of Ti-6Al-4V Alloy by Electrical Discharge Coating Process Using Partially Sintered Ti-Nb Electrode

In the present research, a composite layer of TiO2-TiC-NbO-NbC was coated on the Ti-64 alloy using two different methods (i.e., the electric discharge coating (EDC) and electric discharge machining processes) while the Nb powder were mixed in dielectric fluid. The effect produced on the machined surfaces by both processes was reported. The influence of Nb-concentration along with the EDC key parameters (Ip and Ton) on the coated surface integrity such as surface topography, micro-cracks, coating layer thickness, coating deposition, micro-hardness has been evaluated as well. It has been noticed that in the EDC process the high peak current and high Nb-powder concentration allow improvement in the material migration, and a crack-free thick layer (215 μm) on the workpiece surface is deposited. The presence of various oxides and carbides on the coated surface further enhanced the mechanical properties, especially, the wear resistance, corrosion resistance and bioactivity. The surface hardness of the coated layer is increased from 365 HV to 1465 HV. Furthermore, the coated layer reveals a higher adhesion strength (~118 N), which permits to enhance the wear resistance of the Ti-64 alloy. This proposed technology allows modification of the mechanical properties and surface characteristics according to an orthopedic implant’s requirement

Precision machining of biopolymers: A brief review of the literature and case study on diamond turning

Nowadays, 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

Experimental 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

Development of biosurfactant-based graphene quantum dot conjugate as a novel and fluorescent theranostic tool for cancer

Biosurfactants are amphipathic molecules of microbial origin that reduce surface and interfacial tension at gas–liquid–solid interfaces. Earlier, the biosurfactant was isolated and characterized in our laboratory from Candida parapsilosis. The property of the biosurfactant is further explored in this study by using quantum dots (QDs) as nanocarrier