Although a lot has been done to enhance the machining performance of high strength materials, machining of these materials in an eco-friendly manner is still a challenge. Presently, researchers are ...actively working on MQL base cutting fluids to boost the heat transfer efficiency and lubricating capabilities of the cutting fluids with the application of nanoparticles. Therefore, the present study is focused on the exploration of cooling and lubrication capabilities of different vegetable oil-mixed nanofluids using different nanoparticles (i.e. Al
2
O
3
, MoS
2
, SiO
2,
CuO and graphene) in drilling under MQL technique. The main aim of the current research work is to compare the drilling performance of different cooling environments, viz. dry, flood, pure MQL (PMQL) and nanofluid MQL (NFMQL) with regard to drilling characteristics concerning the thrust force, torque, surface roughness, drill tip temperature and wear mechanism in drilling of AISI 321 stainless steel. The results obtained from the experiments confirm that NFMQL strategies have shown magnificent machining performance by improving machining characteristics. Among the nanofluids, 1.5 wt.% Al
2
O
3
NFMQL cooling strategy delivered a superior cooling–lubricating effect and enhanced the machining characteristics followed by MoS
2
, SiO
2,
CuO and graphene NFMQL conditions. 1.5 wt.% Al
2
O
3
NFMQL drilling had a thrust force, torque, surface roughness and drill tip temperature of 1035 N, 10.8 Nm, 2.902 µm and 56.5 °C, which reduced by 42.81, 64.7, 53.84 and 20.97%, respectively, than that obtained under flood drilling at 30th hole. Moreover, 1.5 wt.% Al
2
O
3
NFMQL condition successfully drilled 30 holes with minimum wear of drill tool as compared to all other drilling conditions under study. The superior performance of Al
2
O
3
NFMQL may be attributed to the fact that Al
2
O
3
nanoparticles with soybean oil performed various tribological enhancement mechanism, i.e. self-repairing or mending mechanism, rolling or ball-bearing mechanism, polishing mechanism and tribo-film formation between the contacting surfaces, which enhance the drilling characteristics.
Due to rising attention towards environmental and ecological issues caused by mineral oil-based lubricants in machining operations, the developing of an environmental favourable lubricant has become ...inevitable. As environmental favourable cutting fluids, vegetable oils have acquired great attention in machining operations due to their good biodegradability, non-toxicity and less environmental pollutant properties. Nowadays, the minimum quantity lubrication (MQL) technique is explored as alternative technique to conventional flood cooling technique. However, very limited work is done to investigate the effect of MQL technique using vegetable oils as the base oil for machining of hard materials. Moreover, systematic comparison of different vegetable oils as the base oil will be of great significance to the manufacturing industry. Therefore, in this study, the performance of six vegetable oils viz. castor, coconut, soybean, canola, palm and sunflower oil, and distilled water has been investigated during drilling of stainless steel (AISI 321) using minimum quantity lubrication technology. The main objective of this study is to compare the performance of various cooling strategies viz. dry, flood and seven MQL conditions with respect to drilling characteristics (thrust force, torque, surface roughness, coefficient of friction (COF), chip morphology and wear mechanism) in the drilling of stainless steel (AISI 321) by using HSS drill tools. Experimental findings showed that MQL drilling conditions have given excellent drilling performance by improving drilling characteristics than dry and flood drilling. Among the MQL fluids, sunflower oil provided better lubrication and improved the drilling characteristics followed by palm, canola, soybean, coconut, castor oil and distilled water. Sunflower oil had a thrust force, torque, surface roughness and coefficient of friction of 1425 N, 22.8 Nm, 4.356 µm and 4.000 µ, which reduced by 21.27%, 25.49%, 30.72% and 5.35%, respectively than that under flood drilling at 30th hole. The better lubrication performance of sunflower oil may be attributed to the rich presence of saturated-fatty acids. In addition, vegetable oils based MQL technique is more worthy to improve the cooling capabilities and promote sustainability in the manufacturing sector by saving resources and extending environmental benefits.
•A new numerical scheme termed as fractional delay block boundary value method (FDBBVM) is proposed.•The FDBBVMs is developed for the fractional delay differential equations with the Caputo ...fractional derivative of order 0<β<1.•The FDBBVM is convergent and globally stable.•The order of the extended BBVMs does not change upon adding delay term to the fractional differential equations.
In this paper, a new numerical scheme termed as fractional delay block boundary value methods (FDBBVMs) is proposed. It is an extended version of the block boundary value methods (BBVMs). The proposed scheme is used to find numerical solutions of the fractional delay differential equations including Caputo fractional derivative of βth order with 0<β<1 and a constant delay term. The estimation of the fractional-order derivative term is obtained by combining the mth-order Lagrange interpolating polynomial along with the pth-order BBVMs, and the constant delay term is dealt with certain modifications in the BBVM. Further, the convergence analysis of the proposed scheme is discussed and it is observed that the FDBBVM is convergent with order min{p,m−β+1}. Moreover, the scheme is shown to be globally stable and its computational efficiency and accuracy has been illustrated with the help of numerical examples.
The development of novel protein sources to compensate for the expected future shortage of traditional animal proteins due to their high carbon footprint is a major contemporary challenge in the ...agri-food industry currently. Therefore, both industry and consumers are placing a greater emphasis on plant proteins as a sustainable source of protein to meet the growing nutritional demand of ever increasing population. In addition to being key alternatives, many plant-based foods have biological properties that make them potentially functional or health-promoting foods, particularly physiologically active peptides and proteins accounting for most of these properties. This review discusses the importance of plant-based protein as a viable and sustainable alternative to animal proteins. The current advances in plant protein isolation and production and characterization of bioactive hydrolysates and peptides from plant proteins are described comprehensively. Furthermore, the recent research on bioactivities and bioavailability of plant protein-derived bioactive peptides is reviewed briefly. The limitations of using bioactive peptides, regulatory criteria, and the possible future applications of plant protein-derived bioactive peptides are highlighted. This review may help understand plant proteins and their bioactive peptides and provide valuable suggestions for future research and applications in the food industry.
In this letter, a simple, effective, and computationally efficient approach for the synthesis of uniformly excited unequally spaced linear antenna (USLA) arrays is proposed. The proposed approach ...deals with determination of optimum elements' density on the aperture, which empowers the synthesis technique with flexibility and increased search competency in attaining maximum possible reduction in peak sidelobe level (PSLL). In the present study, an inertia-weight particle swarm optimization (IW-PSO) algorithm is employed for the synthesis of USLA arrays. Numerical analysis on 16- and 32-element linear arrays is carried out to evidence the effectiveness of the proposed approach. The numerical results obtained through our technique are compared to those employing other techniques available in the literature, which reveals that the proposed scheme outperforms other schemes and offers great flexibility as well as enhances the global search ability of the IW-PSO algorithm in achieving the lowest possible PSLL at reduced computational effort.
In temperate and boreal ecosystems, seasonal cycles of growth and dormancy allow perennial plants to adapt to winter conditions. We show, in hybrid aspen trees, that photoperiodic regulation of ...dormancy is mechanistically distinct from autumnal growth cessation. Dormancy sets in when symplastic intercellular communication through plasmodesmata is blocked by a process dependent on the phytohormone abscisic acid. The communication blockage prevents growth-promoting signals from accessing the meristem. Thus, precocious growth is disallowed during dormancy. The dormant period, which supports robust survival of the aspen tree in winter, is due to loss of access to growth-promoting signals.
Titanium (Ti) and its alloys are widely used as candidate materials for biomedical implants. Despite their good biocompatibility and corrosion resistance, these materials suffer from corrosion after ...implantation in biological environments. The aim of this research work is to study the effect of two coatings on biocompatibility and corrosion behavior of Ti-6Al-4V biomedical implant material. Hydroxyapatite (HA) and hydroxyapatite/titanium dioxide (HA/TiO
2
) coatings were thermal-sprayed on Ti-6Al-4V substrates. In the latter case, TiO
2
was used as a bond coat between the substrate and HA top coat. The corrosion behavior of coated and un-coated samples in Ringer’s solution was studied by potentiodynamic and linear polarization techniques. Before and after corrosion testing, XRD and SEM/EDS techniques were used for the analysis of phases formed and to investigate microstructure/compositional changes in the coated specimens. The cellular response was analyzed by the MTT (microculture tetrazolium) assay. The results showed that both the HA, as well as, the HA/TiO
2
coatings significantly increased the corrosion resistance of the substrate material. The HA coating was found to be more biocompatible as compared to the un-coated and HA/TiO
2
-coated Ti-6Al-4V alloy.
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•Dilute Magnetic Semiconductors (DMS) are key substances for practical applications of spintronic devices.•Method used for thin film preparation is sol–gel based spin coating ...procedure which effectively controls various parameters during thin film preparation.•SHI radiation plays an important role to modify the physical properties of Mn- doped ZnO thin films.•Transition from diamagnetic phase to room temperature ferromagnetism (RTFM) after SHI irradiation suggests induced magnetism in the irradiated film samples.•The study put emphasis on the role of defects like oxygen vacancies (created after SHI irradiation) to be a major reason for various modifications in the properties of these thin films.
Structural, optical, electrical and magnetic properties of Mn doped ZnO thin films prepared using sol–gel route and modified by 100 MeV Ni7+ Swift Heavy Ion (SHI) irradiation with fluence rate of 1 × 1012 and 1 × 1013 ions/cm2 were studied. X-Ray Diffraction (XRD) studies revealed monophasic films with improved crystallinity after SHI irradiation. Field Emission Scanning Electron Microscopy and Atomic force microscopy indicates increment in grain size with enhanced surface roughness. Enhancement of defect structure such as oxygen vacancies (∼520 nm) and surface defects (∼480 nm) have been studied by Photoluminescence spectroscopy. UV–Vis spectroscopy revealed decrease in band gap and transmission values. SQUID magnetometer and Magnetic Force Microscopy studies provided the clear evidence of ferromagnetic hysteresis curve (Mv/sH) and presence of magnetic contrast in highly irradiated films. Presented results favor the role of SHI irradiation for inducing room temperature ferromagnetism in Mn doped ZnO thin films.
Introduction:
Berberine, a protoberberine alkaloid, and its derivatives exhibit a wide spectrum of pharmacological activities. It has been used in traditional Chinese medicine and Ayurvedic medicine ...and current research evidences support its use for various therapeutic areas.
Areas covered:
This review covers the patents on therapeutic activities of berberine and its derivatives in the years between 2009 and 2012. An extensive search was done to collect the patent information using European Patent Office database and SciFinder. The therapeutic areas covered include cancer, inflammation, infectious diseases, cardiovascular, metabolic disorders, and miscellaneous areas such as polycystic ovary syndrome, allergic diseases, and so on.
Expert opinion:
Berberine along with its derivatives or in combination with other pharmaceutically active compounds or in the form of formulations has applications in various therapeutic areas such as cancer, inflammation, diabetes, depression, hypertension, and various infectious areas. Berberine has demonstrated wide physiological functions and has great potential to give a multipotent drug if some inherent problems on poor bioavailability and solubility are taken care of. Additionally, polyherbal formulations with berberine-containing plants as major ingredients can be successfully developed.
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