Boron Nitrate Research Articles

Temperature Analysis in Cubic Boron Nitrate Cutting Tool during Minimum Quantity Lubrication Turning with a Coconut-Oil-Based Nano-Cutting Fluid Using Computational Fluid Dynamics

The minimum quantity lubrication (MQL) approach is used for improving tool life at a low cost, and it is environmentally friendly. When compared to traditional flood cooling technology, the flow rate in MQL is thought to be 10,000 times lower. The workpiece’s surface smoothness is enhanced by continuous chip formation during turning, but because the tool is always in touch with the chip, a crater wear zone is formed on the rake face due to high friction and thermal stress. While adding nanoparticles to MQL enhances cutting performance, a high concentration of these nanoparticles causes burr adhesion and decreased chip evacuation capability due to the agglomeration of nanoparticles, which affects the surface finish of the workpiece. A novel “coconut-oil-based SiC–MWCNT nano-cutting fluid for a CBN insert cutting tool” is proposed in this approach to overcome these issues. Silicon carbide (SiC) and multi-walled carbon nanotubes (MWCNTs) are added to coconut oil with an appropriate volume fraction for better lubrication. The thermal properties of the proposed nano-cutting fluid are compared with those of some existing nano MQL cutting fluids, and it was found that the MQL cutting fluid under consideration exhibits an elevated thermal conductivity and convective heat transfer coefficient that efficiently reduce tool temperature and improve tool life. The comparative study between the Finite Element Simulation using computational fluid dynamics (CFD) predicted variation in tool temperature and the corresponding experimental values revealed a remarkable alignment with a marginal error ranging from 1.27% to 3.44%.

Synthesis of Novel Non-Isocyanate Polyurethane/Functionalized Boron Nitride Composites.

Poly(hydroxyurethanes) (PHUs) have been suggested as isocyanate-free, low-toxicity alternatives to polyurethanes (PUs). However, PHUs present low mechanical properties due to the presence of side reactions that limit the production of high-molar mass polymers. Here, we present the synthesis under mild conditions and atmospheric pressure of bi-cyclic carbonate monomer for the production of PHU nanocomposites with good physical properties. The kinetics of the bi-cyclic carbonate synthesis and its complete conversion to urethane were followed by FTIR. The addition of functionalized boron nitrate (f-BN) with sucrose crystals improved the thermal degradation temperature as well as the glass transition by approximately 20 °C and 10 °C, respectively. The storage modulus of PHU films gradually increases with the concentration of f-BN in the composite.

Graphene-Based Electrochemical Sensors for Psychoactive Drugs

Sensors developed from nanomaterials are increasingly used in a variety of fields, from simple wearable or medical sensors to be used at home to monitor health, to more complicated sensors being used by border customs or aviation industries. In recent times, nanoparticle-based sensors have begun to revolutionize drug-detection techniques, mainly due to their affordability, ease of use and portability, compared to conventional chromatography techniques. Thin graphene layers provide a significantly high surface to weight ratio compared to other nanomaterials, a characteristic that has led to the design of more sensitive and reliable sensors. The exceptional properties of graphene coupled with its potential to be tuned to target specific molecules have made graphene-based sensors one of the most popular and well-researched sensing materials of the past two decades with applications in environmental monitoring, medical diagnostics, and industries. Here, we present a review of developments in the applications of graphene-based sensors in sensing drugs such as cocaine, morphine, methamphetamine, ketamine, tramadol and so forth in the past decade. We compare graphene sensors with other sensors developed from ultrathin two-dimensional materials, such as transition-metal dichalcogenides, hexagonal boron nitrate, and MXenes, to measure drugs directly and indirectly, in various samples.

Electrocaloric Effect of Structural Configurated Ferroelectric Polymer Nanocomposites for Solid-State Refrigeration.

To successfully complete the design of high-performance electrocaloric devices for advanced flexible cooling systems, it is necessary to comprehensively consider the optimization of composite materials, structural design of nanocomposites, and device integration. The cooling power density and energy storage density of various structural configurated poly(vinylidene fluoride) (PVDF)-based polymer nanocomposites are investigated using a phase-field model through the general formulation of a partial differential equation of COMSOL Multiphysics and finite element analysis through Maxwell's equation of conservation of charge. It is revealed that ferroelectric polymer nanocomposites composed of boron nitrate fibers (BNf) + BCZT@BaTiO3(f) + PVDF possess the optimal result regarding their cooling power as well as the energy storage density. The cooling power density of the core-shell-structured BNf + BCZT@BaTiO3(f) + PVDF nanocomposites is evaluated as a function of the volume content, frequency, and electric field, where a remarkable cooling power density of 162.2 W/cm3 is achieved at 4 Hz with energy storage density of 33.4 J/cm3 under a 500 MV/m field. Therefore, by performing the systematic study of the electrocaloric effect in structural configurated ferroelectric polymer nanocomposites for solid-state refrigeration, this opens an avenue for developing remarkably improved power density with reduced weight in aerospace energy storage technology.

Sol-gel synthesized boron nitride (BN) thin films for antibacterial and magnetic applications

Novel devices demand new coatings, to assure best dimensional accuracy and maximum efficiency. Recently, boron nitride thin films are deposited by sol-gel dip coating using two precursors boric acid and boron nitrate. Films have preferred orientation along (002) plane with direct relationship of crystallite size with molarity of precursors. An increase in thickness of thin films is observed for increase in molarity of boric acid but thickness was decreased with molarity of boron nitrate. Also, the band gap increased for both precursors with increase in molarity. Films are found to be ferromagnetic with decrease in saturation magnetization for boric acid and increase for boron nitrate with increase in molarity of both precursors. Dielectric constant and AC conductivity also decrease with increase in molarity of both precursors. Boron nitride has remarkable antibacterial activity against bacterial strains.

A Study on Material Removal Rate and Surface Roughness of Abrasive Water Jet Machining Process on Hybrid Metal Matrix Composites using Response Surface Methodology

Hybrid metal matrix composite (HMMC) plays a crucial role in the development of better and advanced materials and in their automotive and aeronautical applications. In this investigation also HMMC is prepared using aluminium alloy, as matrix of material and boron nitrate and silicon carbide are chosen for reinforcing material and stir casting method is employed to prepare this new HMMC. The abrasive water jet method is employed for machining the developed HMMCs. The Taguchi approach with ANOVA approach is utilized for optimizing the independent machining parameters to exploit removal rate of material and surface roughness is to be minimized. The Taguchi based response surface methodology(RSM) is utilized for optimizing the machining parameters. Based on the response tables, the rate of feed and stand of distance are more influential parameters on the rate of removal of material and roughness of surface. The optimized machining parameters for improving the rate of removal the material are 100mm/min of FR, 1.5mm SOD and 600gm/min. The 125mm/min FR, 1.5mm SOD and 400gm/min AFR are the optimized machining parameters for minimizing the surface roughness.

Metallicity-Dependent Ultrafast Water Transport in Carbon Nanotubes.

Carbon nanotubes (CNTs) with hydrophobic and atomically smooth inner channels are promising for building ultrahigh-flux nanofluidic platforms for energy harvesting, health monitoring, and water purification. Conventional wisdom is that nanoconfinement effects determine water transport in CNTs. Here, using full-atomistic molecular dynamics simulations, it is shown that water transport behavior in CNTs strongly correlates with the electronic properties of single-walled CNTs (metallic (met) vs semiconducting (s/c)), which is as dominant as the effect of nanoconfinement. Three pairs of CNTs (i.e., (8,8)met , 10.85 Å vs (9,7)s/c , 10.88 Å; (9,8)s/c , 11.53 Å vs (10,7)met , 11.59 Å; and (9,9)met , 12.20 Å vs (10,8)s/c , 12.23 Å) are used to investigate the roles of diameter and metallicity. Specifically, the (9,8)s/c can restrict the hydrogen-bonding-mediated structuring of water and give the highest reduction in carbon-water interaction energy, providing an extraordinarily high water flux, around 250 times that of the commercial reverse osmosis membranes and approximately fourfold higher than the flux of the state-of-the-art boron nitrate nanotubes. Further, the high performance of (9,8)s/c is also reproducible when embedded in lipid bilayers as synthetic high-water flux porins. Given the increasing availability of high-purity CNTs, these findings provide valuable guides for realizing novel CNT-enhanced nanofluidic systems.

A comparative investigation on effects of nanoparticles on characteristics of natural esters-based nanofluids

The effects of transformer oil-based nanofluids have been broadly investigated and showcased a magnificent improvement in performance. But in natural esters based nanofluids characteristic performance persist virtually unexplored and still, there is a room for investigation. This work aims to examine the effect of three dissimilar types of nanoparticles such as Aluminum Oxide (Al2O3), Boron Nitrate (BN) and Ferrous Ferric Oxide (Fe3O4) at various volume concentrations on the characteristic performance of natural esters. Honge oil (HO), Neem oil (NO), Mustard oil (MO) and Punna oil (PO) is considered as the base fluid for investigation. The characteristic performances of base fluids are tested before and after blending of nanoparticles as per standards. The findings are quite promising because the performance of nanofluids shows a significant improvement.

Mechanical characteristics of conch shell polymer matrix composites

Innovative materials have found many applications in many areas of daily life for quite some time. Conventional materials like glass, boron nitrate, silicon carbide and metallic binders belong to the group of ceramic matrix composite materials. Substantial development in the field of polymer composites has been achieved in recent years, so that they could be introduced into the most important applications. These new innovative materials open up unlimited possibilities for modern material science and development. With this in mind, in this work a new polymer matrix composite material is developed with the conch shell material called as aragonite and epoxy resin. Test specimens prepared by in situ fabrication method with different volume percentage of conch shell particles. Mechanical characteristics such as tensile strength, impact strength and hardness values were determined. In addition, microstructural analysis reveals that conch shell materials have a crossed-lamellar microstructure and the angle between two second-order lamellae is 70–90°. Fracture morphologies indicate that crack deflection is the major toughening mechanisms.

Island shape, size and interface dependency on electronic and magnetic properties of graphene hexagonal-boron nitride (h-BN) in-plane hybrids

We systematically investigate the energetics of ion implantation, stability, electronic, and magnetic properties of graphene/hexagonal boron nitrate (h-BN) in-plane hybrids through first principle calculations. We consider hexagonal and triangular islands in supercells of graphene and h-BN layouts. In the case of triangular islands, both phases mix with each other by either solely CN or CB bonds. We also patterned triangles with predominating CN or CB bonds at their interfaces. The energetics of island implantation is discussed in detail. Formation energies point out that the island implantation could be even exothermic for all hybrids studied in this work. Effects of size and shape of the island, and dominating bonding sort at the island-layout interfaces on the stability, band gap, and magnetic properties of hybrids are studied particularly. The hybrids become more stable with increasing island size. Regardless of the layout, hybrids with hexagonal islands are all non-magnetic and semiconducting. One can thus open a band gap in the semimetallic graphene by mixing it with the h-BN phase. In general, hybrids containing graphene triangles show metallic property and exhibit considerable amount of magnetic moments for possible localized spin utilizations. Total magnetic moment of hybrids with both graphene and h-BN layouts increases with growing triangle island as well. The spin densities of magnetic hybrids are derived from interfaces of the islands and diminish towards their center. We suggest that the increase in stability and magnetic moment depend on the number of atoms at the interfaces rather than the island size.

Differential Permeability of Proton Isotopes through Graphene and Graphene Analogue Monolayer.

Two-dimensional (2D) monolayer nanomaterials can be exploited as the thinnest membrane with distinct differential sieving properties for proton isotopes. Motivated from the experimental evidence of differential sieving proton isotopes through graphene and hexagonal boron nitrate (h-BN) monolayer, we compute the kinetic barrier of isotope H(+) and D(+) permeation through model graphene and h-BN fragments at the MP2/6-31++G(d,p) level of theory. On the basis of the ratio of tunneling reaction rate constant, the isotope separation ratio of H(+)/D(+) and H(+)/T(+) is predicted to be ∼12 and 37, respectively. The tunneling reaction rate constant can be estimated from the zero-point-energy computed at the transition state for the proton isotope permeation though the 2D model systems. We show that the presence of Stone-Wales (55-77) defect in the model graphene fragment can significantly lower the proton permeation barrier by 0.55 eV. With the defect, the ratio of tunneling reaction rate constant of H(+)/D(+) is increased to ∼25. In addition to model graphene and h-BN, we have examined proton permeation capability of α-boron monolayer. We compute the tunneling reaction pathway for H(+) through α-boron monolayer using both the climbing nudged elastic band (c-NEB) method and the scanning-path method. Both methods suggest that α-boron monolayer entails a relatively low barrier of ∼0.20 eV for H(+) permeation, much lower than that of the model graphene and h-BN fragments. Our studies provide molecular-level insights into the differential permeation of proton isotopes through 2D materials. The methods can be extended to examine isotope separation capability of other 2D materials as well.

Modelling and Analysis of Wear Prediction in Machining of Nano Based GFRP Composites Using RSM

Glass fiber reinforced composite material was fabricated using E-glass fiber with unsaturated polyester resin. In Glass Fiber Reinforced Plastic (GFRP) composites, the matrix of polymer is reinforced with glass fibers. The surface quality and dimensional precision significantly affect the parts during their suitable life, particularly in cases where the components come in contact with other elements or materials. In the current study, GFRP is machined with two cases i.e. with and without Nano combinations in lathe. These machining studies were carried out on lathe using three different cutting tools: namely Carbide (K-20), Cubic Boron Nitrate (CBN) and Polycrystalline Diamond (PCD). The cutting parameters considered were cutting speed, feed, and depth of cut. Surface Finish is the most important parameter measured by main spindle and compares the value with another. A second order mathematical model in terms of cutting parameters was developed using RSM. The results specify the developed model is suitable for prediction of surface roughness in machining of GFRP composites.

1009 感圧塗料を用いたターボファン内部における非定常圧力場の計測技術

Porous pressure sensitive paint (PSP) having fast response and high pressure sensitivity will be a powerful measurement tool to diagnose flow properties in consumer turbomachinery. We have composed test facilities of a turbofan with a transparent casing, to apply a fast-response PSP to measurement of nonstationary pressure distribution on the casing surface of the turbofan. However, luminescent intensity of the PSP without a white undercoat acting as a screen layer is relatively low, which results in low signal-to-noise ratio for pressure measurement. In this study, we have examined the effect of white overcoat with high oxygen permeability made of boron nitrate (BN) nanoparticles, which functions as a screen layer to enhance the luminescence intensity of the PSP through a transparent surface. We have clarified that the BN overcoat can enhance the luminescence intensity and SN ratio of PSP without affecting the time response.

Using 18O/2H, 3H/3He, 85Kr and CFCs to determine mean residence times and water origin in the Grazer and Leibnitzer Feld groundwater bodies (Austria)

Two groundwater bodies, Grazer Feld and Leibnitzer Feld, with surface areas of 166 and 103km2 respectively are characterised for the first time by measuring the combination of δ18O/δ2H, 3H/3He, 85Kr, CFC-11, CFC-12 and hydrochemistry in 34 monitoring wells in 2009/2010. The timescales of groundwater recharge have been characterised by 131 δ18O measurements of well and surface water sampled on a seasonal basis. Most monitoring wells show a seasonal variation or indicate variable contributions of the main river Mur (0–30%, max. 70%) and/or other rivers having their recharge areas in higher altitudes. Combined δ18O/δ2H-measurements indicate that 65–75% of groundwater recharge in the unusual wet year of 2009 was from precipitation in the summer based on values from the Graz meteorological station. Monitoring wells downstream of gravel pit lakes show a clear evaporation trend.A boron–nitrate differentiation plot shows more frequent boron-rich water in the more urbanised Grazer Feld and more frequent nitrate-rich water in the more agricultural used Leibnitzer Feld indicating that a some of the nitrate load in the Grazer Feld comes from urban sewer water. Several lumped parameter models based on tritium input data from Graz and monthly data from the river Mur (Spielfeld) since 1977 yield a Mean Residence Time (MRT) for the Mur-water itself between 3 and 4years in this area. Data from δ18O, 3H/3He measurements at the Wagna lysimeter station supports the conclusion that 90% of the groundwaters in the Grazer Feld and 73% in the Leibnitzer Feld have MRTs of <5years. Only in a few groundwaters were MRTs of 6–10 or 11–25years as a result of either a long-distance water inflow in the basins or due to longer flow path in somewhat deeper wells (>20m) with relative thicker unsaturated zones. The young MRT of groundwater from two monitoring wells in the Leibnitzer Feld was confirmed by 85Kr-measurements. Most CFC-11 and CFC-12 concentrations in the groundwater exceed the equilibration concentrations of modern concentrations in water and are therefore unsuitable for dating purposes. An enrichment factor up to 100 compared to atmospheric equilibrium concentrations and the obvious correlation of CFC-12 with SO4, Na, Cl and B in the ground waters of the Grazer Feld suggest that waste water in contact with CFC-containing material above and below ground is the source for the contamination. The dominance of very young groundwater (<5years) indicates a recent origin of the contamination by nitrate and many other components observed in parts of the groundwater bodies. Rapid measures to reduce those sources are needed to mitigate against further deterioration of these waters.

Influência da velocidade de avanço do rebolo nos danos de aços endurecidos retificados

A tendência mundial é o aumento da produtividade e da produção de peças cada vez mais sofisticadas, com elevado grau de tolerância geométrica, dimensional, com bom acabamento superficial, com baixo custo. A retificação é responsável pelo acabamento final no processo de usinagem de um material. No entanto, danos gerados nesta fase de produção comprometem todos os recursos utilizados nas fases anteriores. Grande parte dos problemas ocorridos na retificação deve-se à enorme temperatura gerada pelo processo devido às condições de usinagem. Atribui-se à velocidade de avanço, que está diretamente relacionada com a produtividade, os danos ocorridos na retificação, ficando esta variável limitada até valores que não proporcione danos. Neste trabalho, através da variação da velocidade de avanço no processo de retificação cilíndrica externa do aço ABNT D6, racionalizando a aplicação de dois fluidos de corte e usando um rebolo superabrasivo de CBN (nitreto de boro cúbico) com ligante vitrificado, avaliou-se a influência da velocidade de avanço nos danos superficiais de aços endurecidos. Os resultados permitiram concluir que a velocidade de avanço associada a uma eficiente refrigeração e lubrificação, não provocou danos térmicos (queima, trincas, tensões de tração) ao material. Tensões residuais e a rugosidade do material retificado apresentaram uma correlação com as condições de usinagem. O trabalho concluiu ser capaz um aumento dos índices de produtividade sem provocar danos nos componentes retificados.

6173. Surface preciption of boron nitrate on the surface of type 304]' stainless steels doped with nitrogen, boron, and cerium

SiGe alloys are currently used for HBT and MOS as epitaxial layers for base or strained channel, respectively. In the poly phase, SiGe has been studied as a replacement for poly-Si in MOS gates due to its lower thermal budget and gate depletion and also due to the Workfunction Engineering for Vt adjustments. However, for application to CMOS technology as poly-SiGe gates, others constrains emerge such as quality of the oxide interface and etch chemistry. For both applications, the Ge fraction normally lies between 20% and 40%. In this study, authors use a low Ge contents (1%) poly-SiGe thin films aiming for MOS gate electrode. The Ge fraction was determined by RBS analysis. 230 nm thick samples were deposited onto 10 nm thermally oxidized 〈1 0 0〉, p-type Si substrates using silane and germane. Films were deposited in the temperature of 500 °C and total pressure of 667 Pa (5 Torr) by vertical LPCVD. The samples were doped using 31P+ ion implantation from 5 × 1014 cm−2 up to 2 × 1016 cm−2 and annealed by RTP (40 s) from 500 °C up to 900 °C. Rs values were obtained by 4-point probe technique and CV curves were extracted from nMOS capacitors with 200 μm diameter. The same processing steps were used to fabricate similar poly-Si samples and capacitors for comparison.The poly-SiGe samples presented Rs values one order of magnitude lower than poly-Si and CV analysis of nMOS capacitors showed very good characteristics. The 1% Ge in the alloy ensures a low thermal budget for the overall process. Although a relatively high annealing temperature (800 °C) must be used to reduce oxide charge and interface traps, the temperature is well below the necessary for poly-Si processing and can allow formation of the shallow junctions needed for next technological nodes.