Search

The soft magnetic properties of Fe-based nano-crystalline alloys depend on the size, shape and crystallization ratio of nanocrystals formed during annealing. To increase saturation magnetization, soft magnetic properties should be reduced by increasing Fe content. Amorphous Fe-B-C-Cu alloys have been reported to be successfully fabricated despite a Fe content of more than 84%. However, clustered rectangular nano-grains were formed during annealing, resulting in an increase in magnetic loss. In this study, to induce the uniform formation of nuclei and suppress crystal clustering, the effects of C, Cu and Nb on the magnetic and microstructural properties of Fe(81-x)B12.5CyCuxNb(6.5-y) (x = 0, 1, 2 and y = 1, 2, 3, 4) were investigated. The results indicated that thermal stability played an important role in the formation of uniformly distributed spherical nano-crystals during annealing.

Nano-crystalline Ti2SC powders were synthesized by a molten salt method with TiS2/3Ti/2C powders as raw materials and KCl–NaCl as the molten salt medium under argon protection. The effect of heat treatment temperature on the composition and morphology of Ti2SC powder was studied. Ti2SC powder can be synthesized at a relatively low temperature by the molten salt method. A high content of Ti2SC powder can be obtained at 1150 °C for 1.5 h. The particle size of the powder was 22.6 nm. Scanning electron microscopy and transmission electron microscopy showed that nano-sized Ti2SC had an average particle size of 20–30 nm.

Decrease of survivability and stability is a major problem affecting probiotic functional food. Thus, in this study, Lactobacillus reuteri TF-7 producing bile salt hydrolase was microencapsulated in whey protein isolate (WPI) or whey protein isolate combined with nano-crystalline starch (WPI-NCS) using the spray-drying technique to enhance the survivability and stability of probiotics under various adverse conditions. Spherical microcapsules were generated with this microencapsulation technique. In addition, the survival of L. reuteri TF-7 loaded in WPI-NCS microcapsules was significantly higher than WPI microcapsules and free cells after exposure to heat, pH, and simulated gastrointestinal conditions. During long-term storage at 4, 25, and 35 °C, WPI-NCS microcapsules could retain both survival and biological activity. These findings suggest that microcapsules fabricated from WPI-NCS provide the most robust efficiency for enhancing the survivability and stability of probiotics, in which their great potentials appropriate to develop as the cholesterol-lowering probiotic supplements.

Objective: Phosphorus doped hydrogenated nano-crystalline silicon (nc-Si:H) thin films were synthesized by catalytic chemical vapor deposition (Cat-CVD) method. Methods: The effect of deposition pressure on opto-electronic and structural properties was studied using various analysis techniques such as low angle XRD analysis, FTIR spectroscopy, Raman spectroscopy, UV-Visible spectroscopy, dark conductivity, etc. Results: From low angle XRD and Raman spectroscopy analysis, it is observed that an increase in deposition pressure causes Si:H films to transform and transit from amorphous to the crystalline phase. At optimized deposition pressure (300 mTorr), phosphorous doped nc- Si:H films having a crystallite size of ∼29 nm and crystalline volume fraction of ∼58% along with high deposition rate (∼29.7 Å/s) have been obtained. The band gap was found to be ∼1.98 eV and hydrogen content was as low as (∼1.72 at. %) for these films. Conclusion: The deposited films can be useful as an n-type layer for Si:H based p-i-n, tandem and c-Si hetero-junction solar cells.

Background: Periodontal dressings are used for wound protection and patient comfort. Nano-silver particles have the ability to promote wound healing through anti-inflammatory properties. Hence, the present study aims to evaluate early wound healing parameters following periodontal surgery using nano-crystalline silver membrane as periodontal dressing. Materials and Methods: Forty-two systemically healthy patients diagnosed with chronic periodontitis indicated for periodontal flap surgery were enrolled for the present study. Post surgery, the patients were randomly allocated to either a nano-crystalline silver dressing (Acticoat™) group (test group) or only the noneugenol dressing group (control group). Plaque index (PI) and wound healing index were recorded at the 7th- and 14th-day postsurgery. The microbiological analysis and vascular endothelial growth factor (VEGF) levels were evaluated at baseline and 7th-day postsurgery. Results: The healing index was significantly higher in the test group as compared to the control group at days 7 and 14 (P < 0.001; P < 0.001). The colony-forming units/ml count of bacteria were significantly reduced postsurgery in the test group (P = 0.019). VEGF levels increased significantly 7th-day postsurgery in the test group (P = 0.001). There was no statistically significant difference in the PI on the 7th-day postsurgery between the two groups (P = 0.173). Conclusion: The results of the study revealed that silver can be used as a potent periodontal dressing ingredient that can decrease the microbial colonization beneath the pack and promote faster healing postsurgery due to its antimicrobial activity.

Anatase TiO2 surfaces have been treated with 2, 4, 6-triphenylpyrylium hydrogen sulfate (TPPHS) or tripyridylporhpyrinatomanganese(II) (MnP) dyes to yield the modified TiO2/ dye surfaces. The modified TiO2/dye surface was then supported onto activated carbon (AC) surfaces to yield a new class of catalytic system AC/TiO2/dye. The catalytic activities of naked TiO2, dye solution, TiO2/dye, and AC/TiO2/dye systems were examined in photo-degradation of Methamidophos (insecticide) in water, using both UV and visible light. All examined systems showed catalytic activity when used either in the UV or the visible regions, but the AC/TiO2/ dye showed the highest activity. The dye role, in enhancing activity of modified surfaces in UV degradation of the examined contaminants, is understandable by a charge-transfer catalytic effect. AC role can be explained by its ability to adsorb contaminant molecules and bringing them closer to catalytic sites. There was no significant temperature effect on catalyst efficiency in Methamidophos photo-degradation. Oxygen is essential for semiconductor photocatalytic degradation of Methamidophos, but higher oxygen concentrations lead to a downturn of the reaction rate.

Anatase TiO2 surfaces have been treated with 2, 4, 6-triphenylpyrylium hydrogen sulfate (TPPHS) or tripyridylporhpyrinatomanganese(II) (MnP) dyes to yield the modified TiO2/ dye surfaces. The modified TiO2/dye surface was then supported onto activated carbon (AC) surfaces to yield a new class of catalytic system AC/TiO2/dye. The catalytic activities of naked TiO2, dye solution, TiO2/dye, and AC/TiO2/dye systems were examined in photo-degradation of Methamidophos (insecticide) in water, using both UV and visible light. All examined systems showed catalytic activity when used either in the UV or the visible regions, but the AC/TiO2/ dye showed the highest activity. The dye role, in enhancing activity of modified surfaces in UV degradation of the examined contaminants, is understandable by a charge-transfer catalytic effect. AC role can be explained by its ability to adsorb contaminant molecules and bringing them closer to catalytic sites. There was no significant temperature effect on catalyst efficiency in Methamidophos photo-degradation. Oxygen is essential for semiconductor photocatalytic degradation of Methamidophos, but higher oxygen concentrations lead to a downturn of the reaction rate.

Extensive burns of more than 50% have high mortality and those over 90% have almost nil survival rate. All resuscitative measures fail as patient gets infected leading to burn wound sepsis causing septicemia and leading to mortality as the end clinical result. So we need clinically evidenced and rationally based burn dressing strategy to increase extensive burn patient survival. This is random retrospective selection of five patients in each two groups from second degree burn patients of more than 50 percent treated by collagen in one group and other by Nanocrystalline Silver dressings and observed for clinical evidence of patients survival keeping all resuscitative and treatment modalities as standard treatment protocol in all cases. The nano crystalline silver dressing is cost effective, rational and evidence based strategy. It is easy to use, has powerful anti bacterial effect, decreased frequency of dressing changes, shortened time of wound cleaning and painless dressing. It helps make the wound sterile for further treatment within a week. It is a great weapon in the hand of Burn Surgeon for rapid and better recovery of patients. This nano crystalline sustained release silver dressings are best suited to take care of burn wounds of more than 50%. Bacteriophages treatment is reserved for multiple drug resistant bacteria and had good recovery. Keywords: Extensive burns, Nano crystalline silver, Acticoat, SSD, Bacteriophage, Collagen, Skin tempII.

Background Bhasmas are traditional Ayurvedic medicines prepared from minerals and metals by tedious process which removes toxic properties of metals and minerals and enhances medicinal properties. We have synthesized abhraka bhasma by two traditional methods and were analyzed during each stage of preparation. Objective The present study deals with the synthesis and characterization of abhraka bhasma by two different methods, method-1 is commonly used for treating anemia and tropical sprue and method-2 for treating chronic cough. Hence attempts have been made to see the physico-chemical differences between these methods by using different analytical techniques. Material and methods Different steps in preparation of abhraka bhasma includes shodhana (purification), dhanyabhraka, marana (incineration) and amritikarana. The prepared bhasma were analyzed by classical ayurvedic tests and modern analytical techniques like XRD, FTIR, Raman spectroscopy, SEM, TEM, EDX, BET, DLS and TGA/DTA. Results The morphological characterization revealed that as-prepared abhraka bhasma products were nano crystalline in nature. Elemental analysis confirms presence of various elements along with carbon suggesting bhasma as herbo-mineral compound. The XRD studies revealed the presence of KMg3(Si3Al)O10(OH)2 in bhasmas. Conclusion Characterization study revealed presence of various bonds of different functional groups and formation of nano particles. Abhraka bhasma prepared by method-2 has more proportion of nano particles than that prepared by method-1 and hence will be more effective in its use.

Thermophysical parameters of Finemet-type initially amorphous alloy produced using rapid quenching technique were determined. The temperature intervals of phase and structure changes have been obtained using calorimetry and non-ambient X-ray diffraction methods. The electric resistance data were recalculated to alloy electrical conductivity which it was recalculated to heat conductivity using the Wiedemann–Franz law. Resulting parameters were used for heat processes simulation that occurs in amorphous material of built-up transformer core during annealing in nanocrystallization temperature interval. Heat treatment of different sizes twisted magnetic cores was optimized.

In the present work the comparison of the effect of traditional, pulse and stress annealing is made by monitoring the important mechanical and magnetic properties of FINEMET type amorphous precursor alloy. The magnetic properties were determined from the shape of magnetization curve (coercive force, anisotropy) during various heat treatments and the mechanical properties were measured using brittleness test. The traditional heat treatments were performed in resistance furnace and the magnetic measurements were performed in astatic magnetometer. The pulse and stress annealing (as well as their combinations) were carried out inside in the magnetometer. The temperature of pulse heat treatments is regulated with the length of current pulse flowing through the sample. After each pulses the magnetization curves were measured in-situ, in the magnetometer.

In this paper, TiO2 is substituted as a nucleating agent in opaque glaze to produce nano-crystalline glaze with high hardness. The crystallization mechanism of glaze was calculated by non-isothermal thermal analysis by Differential Thermal Analysis (DTA), and the glaze was heat treated at the crystallization temperature (Tp). In the case of glaze (88G20T), in which TiO2 was substituted by 20 wt% showed surface crystallization behaviors because the Avrami constant (n) was 1.18 and the activation energy (E) values were 747.0 kJ/mol at the crystallization temperature (Tp2). The microstructure of the glazes without heat-treatment showed that phase separation transferred from spinodal to nucleation-growth as TiO2 substitution increased. The size of droplets was nano-sized, below 100 nm. The glazes heated at the crystallization temperature (Tp) and crystal size of several hundred nm to several μm was observed. The surface hardness of the crystalline glaze showed a high hardness of 6.74 GPa and the degree of crystallization was 47.5% at 80G20T after heat treatment at Tp2 (1207 °C).

Co1–xZnxFe2O4 (x = 0.2, 0.4, 0.6 and 0.8) were synthesized using typical wet chemical co-precipitation technique. The ferrite specimen have been sintered at 700°C and 900°C for three hours in air. ...

Nano crystalline powder of Co–Ni ferrites compounds having the chemical formula Ni1-xCoxFe2O4 with x = 0.0, 0.25, 0.5, 0.75 and 1.0 were prepared by co-precipitation method. The nanoparticles were ...

Through-pores alumina membranes of 50 μm thickness and 70 × 70 mm size have been fabricated to deposit Ni nanowires by electrochemical processing. Due to highly ordered microstructure of the membranes, the pores were filled by nanowires almost to 100%. The membrane nanowires composite morphology, structure and thermodynamic characteristics have been studied by scanning electron microscopy, atomic-force microscopy, X-ray diffraction and differential thermal analysis. The thermal stability of Ni nanowires into porous alumina template and whole composite was determined.

Mg0.2Mn0.8NdxFe2-xO4 (x = 0.000, 0.025, 0.050, 0.075 and 0.010) nano crystalline is synthesized via hydrothermal technique. Single cubic spinel phase is confirmed by XRD and the formation of Mg0.2M...

Recent investigations of fundamental electronic properties (especially the carrier transport mechanisms) of Si nanocrystal embedded in the amorphous SiC films are highly desired in order to further develop their applications in nano-electronic and optoelectronic devices. Here, Boron-doped Si nanocrystals embedded in the amorphous SiC films were prepared by thermal annealing of Boron-doped amorphous Si-rich SiC films with various Si/C ratios. Carrier transport properties in combination with microstructural characteristics were investigated via temperature dependence Hall effect measurements. It should be pointed out that Hall mobilities, carrier concentrations as well as conductivities in films were increased with Si/C ratio, which could be reached to the maximum of 7.2 cm2/V∙s, 4.6 × 1019 cm−3 and 87.5 S∙cm−1, respectively. Notably, different kinds of carrier transport behaviors, such as Mott variable-range hopping, multiple phonon hopping, percolation hopping and thermally activation conduction that play an important role in the transport process, were identified within different temperature ranges (10 K~400 K) in the films of different Si/C ratio. The changes from Mott variable-range hopping process to thermally activation conduction process with temperature were observed and discussed in detail.

Digital printing waste paper fiber/nano-crystalline cellulose/poly (lactic acid) (DPF/NCC/PLA) composites, modified through γ-methacryloxy propyl trimethoxy silane (KH570), isopropyl tri (dioctylpyrophosphate) titanate (TMC201), sodium hydroxide (NaOH), polyethylene glycol 6000 (PEG6000), and a composite silane coupling agent (KH570/PEG6000), were fabricated by melt blending and injection molding and the effects of different modifiers on the properties of composites were studied. Results showed that mechanical properties of the modified composites generally improved, and the best mechanical properties, including flexural, tensile and impact strength, were achieved PEG6000, KH570/PEG6000, and KH570 modification, respectively. Thermal performance analysis showed improved thermal properties of composites treated by KH570, but the crystallinity of the modified materials was increased. Both water absorption and degradation properties showed a decreasing trend, and water absorption performance was obviously improved after KH570/PEG6000 modification. Under the action of several modifiers, the diffusion coefficient, thermodynamic solubility and permeability of composites were reduced to varying degrees. Furthermore, scanning electron microscopy (SEM) demonstrated that interfacial adhesion and composite compatibility were improved with significantly fewer and smaller pores, as well as a fuzzy boundary among the three phases.

Molecular dynamics (MD) analysis of high-temperature deformation behaviour of nano crystalline (NC) Ni and Ni-Zr alloy (3 at% and 6 at % Zr segregated along the grain boundaries (GBs)) havi...

Objective: Despite the higher translucency of nano-crystalline Y-TZP than the conventional Y-TZP, it couldn’t be used in the anterior region of the mouth in its fully anatomical form without veneering for better esthetics. This study evaluated the color change (?E) and translucency parameter (TP) of the bilayered nano-crystalline zirconia restorations after different treatments of the zirconia surface before and after accelerated aging. Material and Methods: Forty samples of inCoris TZI were cut in the form of discs 15 mm (diameter) and 1mm (thickness) so that after sintering each disc dimensions’ would be 12 mm (diameter) and 0.8 mm (thickness). All discs were colored by dipping in aqueous zirconia coloring solution of shade A2, then divided into four groups according to the type of surface treatment received before sintering; being tribochemical silica coating, zirconia powder deposition, glass grading, and a control untreated group. After sintering, all discs were veneered with a layer of porcelain 0.7 mm (thickness) and 12 mm (diameter). (?E) and TP were measured using VITA Easyshade Compact spectrophotometer before and after accelerated autoclave aging. Results: Different surface treatments applied had significant effect (P

Aim: This study aims to evaluate the effect of Platelet Rich Fibrin combined with Nano crystalline Hydroxy appatite bone graft on grade II mandibular furcation involvement. Subjects and methods: Thirty patients having grade II mandibular furcation defects, with vertical probing depth (VPD) ≥5mm and horizontal clinical attachment level (HCAL) ≥3mm. Following phase I therapy were classified into two groups, group1 received NcHA bone graft and group 2 received NcHA+PRF. Clinical and radiographic parameters were recorded at baseline, 6 and 12 months postoperatively. Results: Both treatment groups showed a significant probing pocket depth (PPD) reduction, clinical attachment gain, increase bone density 12‑months after surgery compared with baseline. However, there was a highly significant PPD reduction and clinical attachment gain when PRF was added to NcHA. Conclusion: The NcHA bone graft in combination with PRF demonstrated clinical advantages beyond that achieved by the NcHA alone.

Chloride-malonate deep eutectic solvent (Cm-DES) was applied to synthesize nano-crystalline Zr0.8Sn0.2TiO4 ceramic powder by using Zr(CH3COO)4, SnCl2∙2H2O and Ti(OCH3CH3)4 as raw materials. The nano-crystalline Zr0.8Sn0.2TiO4 powder was obtained at 450 °C, dramatically lower than that by solid state reaction. Meantime, the grain size of as-synthesized Zr0.8Sn0.2TiO4 powder at 450 °C is 10.7 nm. In the synthesized process, Cm-DES, as a solvent and template, affects the synthesis process and the time required for synthesis is greatly reduced. These results show that the Cm-DES is suitable and prospective for the synthesis of nano-crystalline Zr0.8Sn0.2TiO4 ceramic powder, which could contribute to reduce energy consumption and time cost.

Crystalline properties and the microstructure of matter are among the most important factors that determine its efficiency in various applications. The atomic level in the three different phases (macroscopic, micro, and nanoscale) is the primary criterion for which the material is chosen on the basis of the specified applications. As for the case of perovskite materials, they have many types—singles, doubles, and layered—and the stability of the materials depends on these types. For this reason, the discussion in this chapter revolves around the materials and the importance and applications of nano-perovskites, especially in the energy sector, from energy conversion such as fuel cells to energy storage such as lithium batteries. The most important information has been reviewed regarding perovskites at the nanoscale. Furthermore, the efficiency of perovskite has been proven in different energy applications, in addition to its most important characteristics that affect its efficiency in application.

Metal-organic framework (MOF) materials possess the widest versatility in structure, composition, and synthesis procedures amongst the known families of materials. On the other hand, the extraordinary affinity between MOFs and enzymes has led to widely investigating these materials as platforms to support these catalytic proteins in recent years. In this work, the MOF material NH2-MIL-53(Al) has been tested as a support to immobilize by one-step methodology (in situ) the enzyme lipase CaLB from Candida antarctica by employing conditions that are compatible with its enzymatic activity (room temperature, aqueous solution, and moderate pH values). Once the nature of the linker deprotonating agent or the synthesis time were optimized, the MOF material resulted in quite efficient entrapping of the lipase CaLB through this in situ approach (&gt, 85% of the present enzyme in the synthesis media) while the supported enzyme retained acceptable activity (29% compared to the free enzyme) and had scarce enzyme leaching. The equivalent post-synthetic method led to biocatalysts with lower enzyme loading values. These results make clear that the formation of MOF support in the presence of the enzyme to be immobilized substantially improves the efficiency of the biocatalysts support for retaining the enzyme and limits their leaching.