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Magnetic Abrasive Finishing (MAF) revolutionizes surface finishing by utilizing magnetic fields to apply pressure, ensuring exceptionally high-quality surfaces. Its potential for ultra-precise finishing with fine magnetic abrasives is particularly noteworthy. This study analyzes subsurface temperature dynamics during the MAF process on Al-6060, recognizing temperature's pivotal role in shaping surface texture and mechanical-chemical properties. Unbonded magnetic abrasives containing SiC were used without lubrication or coolants in experimentation. Experimental parameters, including machining gap, abrasive weight, voltage, and rotational speed, were systematically varied using a Box-Behnken Design of Experiments. An artificial neural network facilitated comprehensive data modelling, enabling a detailed parametric study. Post-processing surface characterization provided crucial insights into the impact of surface temperature rise on surface finish and hardness. This holistic approach enhances understanding of temperature's influence on MAF efficacy and its outcomes on Al-6060 surfaces. Experimental findings demonstrate MAF's effectiveness in achieving low-temperature finishing of Al-6060, with a maximum surface temperature of 36 °C. ANOVA analysis quantitatively determined that voltage has greatest influence (55.56%), followed by abrasive weight (20.00%) and machining gap (13.89%), with rotational speed having the least impact (2.22%). Qualitatively, the developed ANN model accurately predicted changes in surface roughness (ΔRa), temperature (ΔT), and hardness (ΔH), with maximum errors of 4.107%, 5.588%, and 6.680%, respectively. XRD analysis provided quantitative evidence of SiC diffusion into the surface, resulting in a hardness increase from 2.7 HV to 5.6 HV. Additionally, chemical substrates deposition, such as silicon carbide, kaolinite, iron silicide, and cristobalite, elucidated chemical-mechanical interactions during the process at such low temperatures.

Abstract Phase encoding in quantum key distribution (QKD) enables long-distance information-theoretic secure communication in optical fibers. We present a novel theoretical model characterizing errors from various sources in practical phase encoding-based QKD systems, namely the laser linewidth, detector dark counts, and channel dispersion. This model provides optimized optical pulse parameters and less distortion in pulses, which eliminates system imperfections and leads to a reduced quantum bit error rate (QBER) for practical QKD scenario. This analysis is applicable to various fiber-based phase and time encoding protocols. In particular, we implement this to a differential phase shift (DPS) QKD scheme operating at a 2.5 GHz clock, which produces a secure key rate of 193 bits/s at a fiber length of 265 km and an unprecedented QBER < 1 $$\%$$ % up to 225 km length with standard telecom components. We show that by adjusting the quantum efficiency and dark count rates of detectors, proposed system can establish secure keys up to 380 km distance using standard telecom grade fiber with a QBER of 1.48%. Moreover, the system is compatible with existing optical fiber networks and capable of establishing a secure key exchange between two cities 432 km apart using ultra-low-loss (ULL) specialty fiber.

In the present study, the hybrid coating was developed by HVOF over the cast iron substrate. The hybrid coating material comprises Al _2 O _3 (80% w/w) enriched with graphite, MoS _2, and fumed silica in w/w of 5%, 10%, and 5% respectively. Microstructure and phase composition of prepared coated samples were analyzed by SEM-EDS, XRD and Raman Spectroscopy. The coated samples were heat-treated and their mechanical, electrochemical and tribological behavior was compared with the as-coated samples. There was a considerable change observed in the micro-hardness and anti-corrosion properties of the coated material after heat treatment. The residual stresses in the heat-treated sample decreased compared to the as-coated sample. The high-temperature tribological investigation was carried out in non-lubricated conditions at three different temperatures 30 °C, 150 °C, and 300 °C with a constant load of 40 N and variable sliding speed. The coefficient of friction and wear rate was calculated and it was found that there was a decrement up to 36% in the wear rate of the heat-treated samples compared to the as-coated sample. The SEM morphologies of the wear track showed the presence of small cracks, adhesion, abrasion and smear regions due to plastic deformation.

Bhimal (Grewia oppositifolia) is the most important agroforestry tree species used for fodder, fuel and fiber in the Himalayan region. In the present study, G. oppositifolia-based traditional agroforestry systems were selected for the estimation of carbon stock and the production potential of barnyard millet (Echinochloa frumentacea) and finger millet (Eleusine coracana), with two elevational ranges, i.e., 1000–1400 and 1400–1800 m amsl, in Garhwal Himalaya, India. The results of the investigation showed a decline in the growth and yield attributes of both the millet crops under the G. oppositifolia-based agroforestry system at both elevations as compared to their respective control sites (sole crops). Among the elevations, the total number of tillers per plant (2.70 and 2.48), the number of active tillers per plant (2.18 and 2.25), panicle length (17.63 cm and 6.95 cm), 1000-seed weight (5.49 g and 4.33 g), grain yield (10.77 q ha−1 and 11.35 q ha−1), straw yield (37.43 q ha−1 and 30.15 q ha−1), biological yield (48.21 q ha−1 and 41.51 q ha−1) and the harvest index (22.53% and 27.78%) were recorded as higher in the lower elevation in both E. frumentacea and E. coracana, respectively, while plant population per m2 (18.64 and 25.26, respectively) was recorded as higher in the upper elevation. Plant height for E. frumentacea (180.40 cm) was also observed to be higher in the upper elevation, while for E. coracana (98.04 cm), it was recorded as higher in the lower elevation. Tree carbon stock was reported negatively with an increase in altitude. The maximum amount of sequestered carbon in the tree biomass for G. oppositifolia was 23.29 Mg ha−1 at the lower elevation and 18.09 Mg ha−1 at the upper elevation. Total carbon stock in the tree biomass was reported to be the highest (15.15 Mg ha−1) in the 10–20 cm diameter class, followed by 20–30 cm (6.99 Mg ha−1), >30 cm (2.75 Mg ha−1) and the lowest (2.32 Mg ha−1) in the E. frumentacea and E. coracana was not reduced so severely under the G. oppositifolia system; however, keeping in mind the other benefits of this multipurpose tree, i.e., carbon sequestration and socioecological relevance, farmers can get benefit from adopting these crops under G. oppositifolia-based agroforestry systems.

Since their discovery, carbon nanotubes (CNTs) have been considered to be promising candidates for polymer-based solar cells, but their functional incorporation and utilization in such devices have been limited due to processing bottlenecks. Here, we demonstrate the realization of controlled placement of a single-walled CNT (SWNT) monolayer network at four different positions in polymer-fullerene bulk-heterojunction (BHJ) solar cells. SWNTs were deposited by dip-coating from a hydrophilic suspension, and a very brief, largely nondestructive argon plasma treatment of the active layer was utilized for incorporation of a SWNT layer within or above it. We demonstrate that SWNTs on the hole-collection side of the active layer lead to an increase in power conversion efficiency (PCE) of the photovoltaic devices from 4 to 4.9% (under AM 1.5 G, 1.3 suns illumination). This is the highest reported PCE for polymer-based solar cells incorporating CNTs, upon consideration of expected scaling of device parameters for 1 sun illumination. We also observe that SWNTs deposited on the top of the active layer lead to major electro-optical changes in the device functionality, including an increased fluorescence lifetime of poly-3-hexylthiophene (P3HT). [ABSTRACT FROM AUTHOR]

Here we report a novel hybrid organic–inorganic anode for organic light-emitting diodes(LEDs) and photovoltaic (PV) cells. This hybrid anode structure is realized from acomposite of poly(3,4-ethylene dioxythiophene) doped with polystyrenesulfonic acid(PEDOT:PSS) and indium tin oxide (ITO) nanoparticles. Owing to the phase separation,this anodic structure leads to a graded work function from patterned ITO tothe photoactive polymer, which in turn reduces the barrier height for holes by∼70%. The resulting devices based on this design show up to 67% reduction in turn-on voltage(for polymer LEDs) and up to 40% increase in short-circuit current and power conversionefficiency (for PV cells). Current–voltage characteristics, Fowler–Nordheim analysis,SEM imaging and energy band diagram analysis are employed to characterize theimproved performance of our devices. The reported approach is expected to beimmensely useful for the molecular design of next-generation efficient organic devices. [ABSTRACT FROM AUTHOR]

Ordered and free-standing metallic nanowires were fabricated by e-beam deposition on patterned polymer templates made by interference lithography. The dimensions of the nanowires can be controlled through adjustment of deposition conditions and polymer templates. Grain size, polarized optical transmission and electrical resistivity were measured with ordered and free-standing nanowires. [ABSTRACT FROM AUTHOR]

We have developed multicolour hybrid DNA probes employing green, yellow and orange colour quantum dot conjugated molecular beacons with black hole quencher 2. Optical and electrophoretic characterization revealed fluorescent energy transfer that follows the FRET mechanism with single nucleotide discrimination. Target DNA identification was observed to be highly sensitive up to 8 ng in gel electrophoresis. Comparison with the conventional organic dye SYBR GoldT showed that our hybrid nanoprobes exhibit more stable performance with less background signal. [ABSTRACT FROM AUTHOR]