Use Of Nano Research Articles

PERFORMANCE EVALUATION OF NANO GRAPHITE INCLUSIONS IN CUTTING FLUIDS WITH MQL TECHNIQUE IN TURNING OF AISI 1040 STEEL

Liberation of heat and generation of friction assoc iated with any machining operation ever pose a prob lem which not only reduce the tool life but also impair quality of the product. C utting fluids have been the conventional choice to curtail friction and temperatures in machining because of its lubrication and cooling ac tions. However, considering health hazards posed by the conventional cutting fluids to health of the workers and ecology, the qu est is towards identifying alternative strategies tthe usual flood application. Selection and use of proper lubricant that can impr ove the overall cutting phenomena which is an impor tant aspect in reducing the cutting forces and temperatures The present work st udies the use of nano cutting fluids in MQL which i s a minimal cutting fluid technique, for turning operation using HSS and ceme nted carbide tools. Development of nano materials b y nanotechnology technique, dispersing them in the cutting fluid improve the ef fectiveness of the cutting fluid and hence nano gra phite powder is selected of particle size 80 nm in varying proportions i.e. 0.0 %, 0.1%, 0.3% and 0.5% by weight are mixed in water soluble oil and applied drop by drop. Experimentation is carried out at differen t flow rates like 5 ml/min 10 ml/min and 15 ml/min with nanoparticle suspended fluids along with dry machining, flood coolant mach ining under constant cutting conditions. Experiment al results are very encouraging with much reduction in surface roughnes s, tool flank wear, temperatures and cutting forces is observed in fluids with nanoparticle inclusions. Different properties of th e nanofluids are estimated through a series of stan dard tests.

Using Functional Nano- and Microparticles for the Preparation of Metal–Organic Framework Composites with Novel Properties

A critical materials challenge over the next quarter century is the sustainable use and management of the world's natural resources, particularly the scarcest of them. Chemistry's ability to get more from less is epitomized by porous coordination polymers, also known as metal-organic frameworks (MOFs), which use a minimum amount of material to build maximum surface areas with fine control over pore size. Their large specific surface area and tunable porosity make MOFs useful for applications including small-molecule sensing, separation, catalysis, and storage and release of molecules of interest. Proof-of-concept projects have demonstrated their potential for environmental applications such as carbon separation and capture, water purification, carcinogen sequestration, byproduct separation, and resource recovery. To translate these from the laboratory into devices for actual use, however, will require synthesis of MOFs with new functionality and structure. This Account summarizes recent progress in the use of nano- and microparticles to control the function, location, and 3D structure of MOFs during MOF self-assembly, creating novel, hybrid, multifunctional, ultraporous materials as a first step towards creating MOF-based devices. The use of preformed ceramic, metallic, semiconductive, or polymeric particles allows the particle preparation process to be completely independent of the MOF synthesis, incorporating nucleating, luminescent, magnetic, catalytic, or templating particles into the MOF structure. We discuss success in combining functional nanoparticles and porous crystals for applications including molecular sieve detectors, repositionable and highly sensitive sensors, pollutant-sequestering materials, microfluidic microcarriers, drug-delivery materials, separators, and size-selective catalysts. In sections within the Account, we describe how functional particles can be used for (1) heterogeneous nucleation (seeding) of MOFs, (2) preparation of framework composites with novel properties, (3) MOF positioning on a substrate (patterning), and (4) synthesis of MOFs with novel architectures.

Deposition of MoS2 particulate layers by pressure impregnation of porous sliding bearings

With the rapid development of industries and advanced technologies, more and more mechanical devices are required to work at high temperatures. The use of nano- and micro-particle solid lubricants is attracting great attention, particularly for high temperature applications. The structure of the solid lubricant particulate layer together combined with particle functionality determines its performance. The formation of a solid lubricant powder layer with a certain thickness, density and morphology is of great importance to solve the problem of high temperature lubrication. A pressure impregnation/filtering technology is applied for this purpose. The paper describes the phenomena encountered in the pressure filtration operation and defines the parameters of the pressure impregnation technology.

Sintering of HA/Zirconia Composite for Biomedical and Dental Applications: A Review

Hydroxyapatite is a calcium phosphate product that being widely use in medical application due to its excellence biocompatibility. However its application has being limited due to the inferior mechanical properties, many researcher attempted to improve its mechanical properties. HA-ZrO2 composites have great potential because of their advantages from both constituent materials, such as the excellent biocompatibility of HA and the considerable mechanical strength and toughness of ZrO2. The synergy of the two materials provides a new possibility for developing a composite material with better properties than monolithic ZrO2 and HA. In this work, the stages of development, as well as the different sintering and processing methods of HA and ZrO2 such as conventional sintering, solid-state reaction, microwave sintering and hot isostatic pressing were discussed. It can be concluded that hot isostatic pressing processing yield the most satisfying result amount above method, however the use of nano structured material maybe able to provide alternative processing method and yield better result.

Nano Colorful Cement Composite

The purpose of this study is to investigate the strength and mechanical properties of concrete by partial replacement of cement with nano-pigment particles. Nano-pigment particles with the average diameter of 120 nm were used with ten different contents of 0.5%, 0.1%, 1.5% and 4.0% by weight. have been investigated by scan electron microscopy(SEM) ,¬X-ray diffraction(XRD).The results showed that the use of nano- pigment particles up to maximum replacement level of 4.0% produces concrete with improved strength and mechanical properties The SEM study of the microstructures between the cement mortar mixed with the nano-pigment particles and the plain cement mortar showed that the nano-pigment particles as a partial replacement of cement up to 4 wt% could accelerate C–S–H gel formation as a result of the increased crystalline Ca(OH)2 amount at the early ages of hydration.

Size-selective absorption and adsorption in anionic pigmented porous coating structures: case study cationic starch polymer versus nanofibrillated cellulose

The use of nano- or microfibrillar cellulose (NFC or MFC) in papermaking is generally hampered by high cost and potentially wasteful use in typical wet end applications. The solubility and fines nature of the material makes it inefficient to retain, and when retained it is generally inefficiently applied within the spatial distribution of the paper fibre matrix. The benefits of capturing the important NFC in a layer structure, to enhance surface and stiffness properties of paper, board and laminates whereby NFC is entrapped at the surface of a fibrous web by forming an in situ composite, were previously shown for the exemplified case of modified porous calcium carbonate, as might be used in an inkjet coating application (Ridgway and Gane in Cellulose 19(2):547–560, 2011). The NFC is seen to integrate itself within the larger interparticle porous structure providing excellent holdout and thin layer continuity, essential in developing an efficient concentration of the NFC at the surface of the substrate. The effect is likened to the well-known I-beam construction. The concept need not be confined to porous pigments, as any pigment coating structure that absorbs and holds the NFC, thus creating an in situ composite, could be used. The aim of this study is to look at a range of different pigments and investigate how these could be used as coating structures by measuring the effect on the pore structure before and after absorbing NFC. This is achieved by using model porous tablet blocks made from the respective anionic coating formulations. The penetration of cationic starch solution, as might be applied for surface sizing on paper, is studied for comparison. The use of cationic starch is considered in the industry to provide reasonably effective surface concentrations due to the electrostatically driven adsorption to the anionic pore surfaces. The effect of water alone on the coating structure has also been measured to allow for structural relaxation, considered to be mainly related to the swelling properties of the anionic polyacrylic coating pigment dispersant. The results illustrate the size-exclusion properties of the pore structure in relation to the material being absorbed and partial resistance to bulk penetration by pore wall adsorption in the case of oppositely charged species. The distribution of the absorbate throughout the pore network can be derived using mercury intrusion porosimetry and electron microscopy, and is deemed critical in respect to controlling the end performance properties, be they, for example, barrier, strength-enhancing applications, or both.

Anti-Counterfeit, Advanced Microelectronics Packaging Solutions for Miniaturized Medical Devices

The medical industry is clearly and urgently in need of development of advanced packaging that can meet the growing demand for miniaturization, high-speed performance, and flexibility for handheld, portable, in vivo, and implantable devices. To accomplish this, new packaging structures need to be able to integrate more dies with greater function, higher I/O counts, smaller die pad pitches, and high reliability, while being pushed into smaller and smaller footprints. As a result, the microelectronics industry is moving toward alternative, innovative approaches as solutions for squeezing more function into smaller packages. This paper discusses the development of advanced packaging that can meet the growing demand for miniaturization, high-speed performance, and flexibility for miniaturized electronic devices. In particular, recent developments in high density interconnect (HDI) substrate technology are highlighted. System-in-Package (SiP), embedded passives, stacked packages, and flex substrates are utilized to achieve significant reduction in size, weight, and power (SWaP) consumption in electronic devices. The paper also describes a novel approach for the fabrication of silicone-coated flexible substrates to provide biocompatibility for implantable devices. In particular, we highlight recent developments on silicone coatings on high density, miniaturized polyimide-based flexible electronics. A variety of high density circuits ranging from 11 microns lines/space to 25 microns lines/spaces were processed on polyimide flex substrates and subsequently coated with biocompatible silicone coatings. The electrical performance of silicone coated batteries was characterized by voltage measurements. The final structure enhances the stretching capability. Fabrication of advanced medical substrates incorporating technologies for parts authentication (anticounterfeit measures) such as embedded signature circuits and use of nano or micro materials as signatures are discussed. In some instances, these measures do not add cost to package fabrication.

Textile materials for electromagnetic field shielding made with the use of nano- and micro-technology

Abstract Studies have been carried out aimed at the development of structures and technology for making special multi-layer textile-polymeric systems of shielding electromagnetic field (EMF). The use of textiles as EMF shielding materials is commonly known, however the EMF attenuation obtained practically exclusively results from the reflection of EMF, while the materials used for this purpose as a rule, show poor EMF absorption abilities. The basic assumption for a new solution is the exploitation of the multiple internal reflection of incident EMF either in textile-polymeric coating materials containing fine-particle electromagnetic materials or in special textile structures. This paper presents the results of investigating the EMF shielding effectiveness of several selected and developed textile-polymeric materials in respect of both their practical applications (protective clothing elements, technical materials, masking elements, etc.) and the structure and content of components with various EMF reflection and absorption properties. The measurement method for independent determination of reflection and transmission coefficients with a wavequide applicator was used. The results obtained with the 2.5 GHz to 18 GHz frequency range show a low value of transmission coefficient (min. −35 dB) and accepted reflection attenuation from about −4 dB to −15 dB for higher frequencies.

Zero valent nano-sized iron/clinoptilolite modified with zero valent copper for reductive nitrate removal

Nitrates constitute one of the main toxic contaminants of groundwater. On the other hand, groundwater may be considered anoxic (oxygen concentration less than 9μgL−1). This fact justifies the use of nano zero valent metals for nitrate removal. In such conditions, zero valent metals are quite stable against oxidation due to the very low level of dissolved oxygen concentration. It has been shown that the performance of zero valent iron coated clinoptilolite zeolite for the reduction of nitrate anion in un-buffered conditions may be enhanced by coating small amounts of Cu0 onto the freshly prepared Fe0/zeolite composite. An optimum loading of Cu0 exists for which the rate of nitrate removal is maximal. For this optimal composition, the nitrite anion production curve with time passes through a maximum. Nitrite production, however, is slightly higher for the Cu modified zeolite. It has been shown that the nitrate removal process is only slightly dependent on the initial solution pH. In the temperature range of 20–60°C, the process is controlled by both the liquid phase mass transfer and intrinsic reaction rate resistances. FESEM analysis of the zero valent metal/zeolite composite showed that upon the metal reduction reaction, an egg-shell distribution of zero valent metal in the zeolite agglomerate particle is produced.

Nano- and micro-scale piezomotors

The use of nano- and micro-scale piezomotors in precision electromechanical systems is considered. The deformation of the piezoconverter corresponding to its stress state is investigated.

Study of the Mechanical and Dynamic Mechanical Properties of Polypropylene/Talc/Nanoclay Ternary Nanocomposites

Inorganic micro and nano fillers such as talc and nanoclay are used to improve various properties of polypropylene (PP). In general, the use of inorganic fillers affects the mechanical, rheological and service temperature of the matrix. In recent years, the simultaneous use of nano and micro fillers and investigation of the effect of these hybrid systems on various properties of the composite has gained the attention of many scientists. In this work, ternary nanocomposites, PP/talc/nanoclay, were prepared via melt compounding of the ingredients in a twin-screw extruder. The dispersion status of the fillers was followed by XRD and TEM techniques. The mechanical and dynamic mechanical properties of the composites were investigated in comparison to the binary composites (PP/talc and PP/nanoclay). The results showed that in ternary nanocomposites, the nanoclay was better exfoliated than that of PP/nanoclay composite. This could be due to higher matrix viscosity as the result of the presence of talc, which provides a balance between shear stress and molecular diffusion. As a result of this better exfoliated structure, a substantial increase in modulus, yield stress and other mechanical and dynamic mechanical properties was achieved in PP/talc/nanoclay nanocomposites.

Nanoscale zero valent iron and bimetallic particles for contaminated site remediation

Since the late 1990s, the use of nano zero valent iron (nZVI) for groundwater remediation has been investigated for its potential to reduce subsurface contaminants such as PCBs, chlorinated solvents, and heavy metals. nZVI shows tremendous promise in the environmental sector due to its high reactivity and as such, numerous laboratory and field studies have been performed to assess its effectiveness. This paper reviews the current knowledge of nZVI/bimetallic technology as it pertains to subsurface remediation of chlorinated solvents and heavy metals. The manuscript provides background on the technology, summarizing nZVI reactions with chlorinated solvents and metals, and examines the factors affecting nZVI reactivity. Studies on subsurface transport of bare and coated nZVI particles are also reviewed and challenges with field implementation are discussed. This manuscript offers a comprehensive review of nZVI technology and highlights the work still needed to optimize it for subsurface remediation.

Constructing NFC-pigment composite surface treatment for enhanced paper stiffness and surface properties

The use of nano- or microfibrillar cellulose (NFC or MFC) in papermaking is generally hampered by high cost and potentially wasteful use in typical wet end applications. The solubility and fines nature of the material makes it inefficient to retain, and when retained it is generally inefficiently applied within the spatial distribution of the paper fibre matrix. To illustrate the benefits of capturing the important NFC in a layer structure to enhance surface and stiffness properties of paper and board, we present a study whereby NFC is entrapped at the surface of a fibrous web by forming an in situ composite using a porous coating layer, consisting in the exemplified case of modified calcium carbonate. It is shown that NFC can integrate itself within the porous structure providing excellent holdout and thin layer continuity essential in developing an efficient concentration of the NFC at the surface of the substrate. The effect is likened to the well-known I-beam construction. An additional feature is the potential for recycling the remaining fibrous content in the NFC or, more particularly, MFC product after the nanocrystalline cellulose (NCC) gel fraction has been absorbed, allowing for further efficient processing if needed and hence providing a potential cost reduction in the overall NFC/MFC production. The increased smoothness and uniformity obtained is illustrated by confocal laser profilometry and electron microscopy. The effect on permeability is also illustrated.

Engineering Approaches Toward Deconstructing and Controlling the Stem Cell Environment

Stem cell-based therapeutics have become a vital component in tissue engineering and regenerative medicine. The microenvironment within which stem cells reside, i.e., the niche, plays a crucial role in regulating stem cell self-renewal and differentiation. However, current biological techniques lack the means to recapitulate the complexity of this microenvironment. Nano- and microengineered materials offer innovative methods to (1) deconstruct the stem cell niche to understand the effects of individual elements; (2) construct complex tissue-like structures resembling the niche to better predict and control cellular processes; and (3) transplant stem cells or activate endogenous stem cell populations for regeneration of aged or diseased tissues. In this article, we highlight some of the latest advances in this field and discuss future applications and directions of the use of nano- and microtechnologies for stem cell engineering.

Nano-Particles in Concrete and Cement Mixtures

The construction industry uses concrete to a large extent. currently, the most active research areas dealing with cement and concrete are: understanding of the nanostructural properties of cement and the use of nano–particles, here, Ti nanoparticles in these mixtures. We have synthesized nanoparticles with sol-gel method at 500°C in ambient media and studied their nanostructures with using SEM (scanning Electron Microscopy) technique. The obtained results show that nanosilica can make more stable structure of concrete and/ or cement mixtures.

NANO-GOLD AND NANO-ZINC OXIDE: EFFECT ON GUSTATORY RECEPTOR GENES IN FLIES

Drinking colloidal gold as elixir of life is an age-old practice worldwide. A large body of data containing patients' experiences after intake of colloidal gold for long duration would be available in the medical records of hospitals. ZnO has been approved by FDA for topical use and not for oral intake. Drosophila melanogaster (wild type) strains were fed with physiologically relevant concentrations of nano-gold and nano- ZnO along with appropriate controls. Citrate-capped nano-gold (average particle size is 15–20 nm) synthesized by reducing hydrogen tetrachloroaurate with 1% trisodium citrate and custom-made nano- ZnO , purchased from M K Implex, Canada (average particle size 50 nm) were used as treatments. Microarray studies revealed that fly trehalose receptor genes, Tre and Tre1, are both unaffected after nano-gold and nano- ZnO treatment. Gr64 subfamily members (encoding sugar receptors like glucose, sucrose, and maltose), for example, Gr64a-b become downregulated, but Gr64c, Gr64d, Gr64f remain unaltered in case of both the treatments. Among bitter receptor genes, Gr66a is the most well studied and shows significant downregulation by nano-gold and not by nano- ZnO . Ppk11 and Ppk19 are gustatory ion channel genes which modulate salt perception. Ppk11 was found to be downregulated by both nano-gold and nano- ZnO , while ppk19 expression is suppressed by nano-gold treatment but not by nano- ZnO . The effects of these two nanoparticles on pheromone receptors (Gr32a, Gr39a, and Gr68a) and CO 2 receptors (Gr21a and Gr63a) are presented. To the best of our knowledge, this is the first report on the effect of pure nanoparticles on gustation. Data has been analyzed in the light of the age-old tradition of oral administration of the nano-gold viz-a-viz topical use of nano- ZnO . These results would have far reaching implications in the design of nano-gold mediated oral drug delivery of cancer and other drugs as well as nano- ZnO coated drugs/cosmetics and nano- ZnO carrier based drug delivery in skins and in other topical applications.

Research perspectives and role of lactose uptake rate revealed by its study using 14C-labelled lactose in whey fermentation

The present investigation examines the effect of pH, temperature and cell concentration on lactose uptake rate, in relation with kinetics of whey fermentation using kefir and determines the optimum conditions of these parameters. Lactose uptake rate was measured by adding 14C-labelled lactose in whey. The results reveal the role of lactose uptake rate, being the main factor that affects the rate of fermentation, in contrast to the activity of the enzymes involved in lactose bioconversion process. Lactose uptake rate results discussion showed that mainly Ca2+ is responsible for the reduced whey fermentation rate in comparison with fermentations using synthetic media containing lactose. Likewise, the results draw up perspectives on whey fermentation research to improve whey fermentation rate. Those perspectives are research to remove Ca2+ from whey, the use of nano and microtubular biopolymers and promoters such as γ-alumina pellets and volcan foaming rock kissiris in order to accelerate whey fermentation.

The use of nano and micron-sized particles to enhance the interlayer adhesion in self-reinforced, single-polymer composites

Recent work has shown that the interlayer adhesion of single-polymer composites produced by the Leeds hot compaction process can be significantly improved by either introducing interleaved films of the same polymer between the layers of woven oriented tapes that make up the composite or by the incorporation of carbon nanofibres (CNF) into the oriented tapes prior to hot compaction, or by a combination of these two approaches to produce a synergistic effect. Following on from these findings, we have now investigated the changes in the interlayer peel strength caused by incorporating other micron and nano-scale fillers into polypropylene films which are interleaved into the interlayer region of the hot compacted composite. The filler initially chosen for this study was talc, but a number of other fillers have also been investigated. Scanning electron microscopy has been used to image the peel surfaces and to undertake a preliminary study of the effects of particle size and shape on the peel strength.

Study of the rheological properties of polypropylene/talc/nanoclay ternary hybrid nano composites

AbstractModification of polypropylene (PP) properties by the addition of particulate fillers has been of interest for several years. In the recent years, the simultaneous use of nanofillers and conventional reinforcing fillers and study of the effect of these hybrid systems on various properties of composite has gained the attention of many researchers. In this paper, nanocomposites based on PP/Talc/Nanoclay were prepared at various filler levels via melt compounding of the ingredients in a twin-screw extruder. Here, a polypropylene grafted maleic anhydride (PP-g-MA)/Nanoclay master batch was prepared at 140 oC. The masterbatch was then used to prepare ternary compounds through a simultaneous feeding system, in a ZSK extruder at 210 °C. The extrudate was granulated and then re-extruded through a slit die, to prepare the test specimens. SEM and XRD analysis were used to characterise the systems. Rheological behaviour of the specimens was studied using a parallel plate rheometer. In the ternary blend on comparing with the neat PP, the complex viscosity (η*) is increased with increasing overall filler content; however, at low frequencies this increase is governed by the content of nano filler while at high frequencies it is mainly determined by talc content. A similar trend was also observed for the variations of storage modulus (G′) and loss modulus (G″) with frequency. The results showed that the simultaneous use of nano and micro size fillers considerably affects the melt elasticity. It is believed that the hybrid system increases the hydrodynamic effect of filler particles in the molecular motion of the polymer.

The use of nano supported nickel catalyst in reduction of p-nitrophenol using hydrazine as hydrogen donor

p-Aminophenol was prepared by hydrogenation of p-nitro phenol over nano-sized nickel catalysts supported on two different supports, SiO2 and Al2O3. Hydrazine hydrate was used as hydrogen source in this reaction. Several loadings of nano-sized Ni were used, thus 20, 5, and 2.5 wt% were prepared. X-ray diffraction (XRD) and electron spin resonance (ESR) were employed to investigate the prepared catalysts. The Ni/Al2O3 was found to be more effective and give high durability. The catalytic activity of the reaction was found to be influenced by both the crystallinity of the nickel and the strain among nano-sized nickel particles. The prepared catalysts showed higher catalytic activity, especially at lower loading. During the reaction, a detectable change of the color was observed from yellow to green and finally to colorless, which enable us to suppose a mechanism of this reaction.