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This article considers the potential payoffs of the diasporic as an analytical category developed from Indian Ocean histories that are related to and distinct from various castings of the global. Historically tracing the Indian Ocean trajectories of a Sufi Muslim family from Hadhramawt in relation to changing terms of sovereignty from the late-eighteenth century through the interwar period, the contours and crises of a normative framework for collective and individual life are recuperated and reexamined. The history of these individuals and the theory of life they presuppose and at times explicitly predicate or oppose afford the historian a view of the diasporic as capable of materializing the simultaneity of this- and other-worldly modes of existence. The article concludes that mystical interruptions of historical time that a critical diasporic lens again makes legible as an enduring global form of life represent rarely appreciated sites of emancipation.

History has been difficult to dislodge from its colonial trajectory in spite of at least a half-century of post-Orientalist critique. Accordingly, a critical theory that is genuinely global in its lineaments is difficult to establish as practice without more decolonial histories of the modern world. This article thus moves on two fronts in order to meet the stated objectives of expanding the field of critical theory while tracking “untimely traditions” and the horizons they've drawn. It will offer a history of anticolonial practice that was simultaneously theorized within a distinct Islamic mystical tradition and against a globally emerging conception of state sovereignty (on which much of history writing wittingly or unwittingly concentrates). These political and intellectual histories converge around the biography of a nineteenth-century itinerant Sufi, Sayyid Fadl Ibn Alawi. The critical potentiality of this life will be extrapolated into the present by considering the death-defying horizons opened by the newly expanded repertoire available to a mystical tradition, which allows reflection on the anticolonial as an ontology refused and yet a promise. Finally, the article seeks to answer a question that was only treated partially in the author's recent book For God or Empire. Does the mysticism of this tradition devolve into apolitical practices, or does its survival and even proliferation compel a revisioning of emancipation in history and in theory?

A unique V-shaped MnO2 nanostructure is synthesized with a weak acid (acetic acid) using the microwave-assisted hydrothermal technique. To improve the performance of MnO2 in supercapacitor applications, its composite was prepared with reduced graphene oxide (rGO), i.e., MnO2/rGO, with different weight ratios of MnO2 and rGO. The specific capacitance values of the as-synthesized V-shaped MnO2 nanostructure and MnO2/rGO nanocomposite were calculated to be 64.75 and 88.95 F g−1 at a current density of 0.5 A g−1, respectively, in 1 M Na2SO4 electrolyte. Furthermore, a two-electrode asymmetric supercapacitor device was fabricated using the MnO2/rGO nanocomposite as a positive electrode and activated carbon as a negative electrode. The device has shown energy densities of 25.14 and 17.95 W h kg−1 at 0.25 and 1 kW kg−1 power densities, respectively. These values suggest that the MnO2/rGO nanocomposite is a promising material for supercapacitor devices.

Study Design: Retrospective study.Purpose: To compare perioperative outcomes, patient-reported outcome measures (PROMs), and minimal clinically important difference (MCID) achievement rates for an obese patient cohort between single-level minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) vs. anterior lumbar interbody fusion (ALIF).Overview of Literature: To the best of our knowledge, no study has compared the outcomes of MIS TLIF and ALIF in an obese population.Methods: Obese patients (body mass index [BMI] ≥30.0 kg/m2) who underwent single-level MIS TLIF or ALIF at L5/S1 were included in the study. Demographic/perioperative variables, presenting patient pathology, and 1-year arthrodesis statistics were collected. PROM scores for Visual Analog Scale (VAS) back/leg, Oswestry Disability Index, 12-item Short Form Physical Composite Scale, and Patient-Reported Outcome Measurement Information System Physical Function (PROMIS-PF) were collected from preoperative and postoperative (6 weeks, 12 weeks, 6 months, 1 year, 2 years) PROMIS-PF. The obese patients were classified based on the procedure they underwent (MIS TLIF vs. ALIF).Results: The criteria were met by 210 patients in total. After coarsened exact matching for Charlson comorbidity index score, degenerative spondylolisthesis, isthmic spondylolisthesis, degenerative scoliosis, foraminal stenosis, insurance, male, and ethnicity, 94 obese patients were included in the total cohort, with 59 receiving MIS TLIF and 35 receiving ALIF. ALIF recipients had higher PROMIS-PF scores at 6 weeks (p=0.014) and 12 weeks (p=0.030), as well as a higher VAS leg at 2 years (p=0.017). Following multiple regression accounting for differences in baseline BMI, only the 6-week PROMIS-PF significantly differed (p=0.028), with no other intergroup differences in mean PROMs between fusion types. Aside from a significantly higher 6-week MCID achievement rate for PROMIS-PF among ALIF recipients (p=0.006), no differences in attainment were observed.Conclusions: There were no statistically significant differences in perioperative characteristics, fusion rates, PROMs, or MCID achievement between obese patients receiving MIS TLIF vs. ALIF. As a result, our findings indicate that MIS TLIF and ALIF at L5/S1 are equally effective in an obese patient population.

Copper oxide (CuO) nanoflowers were synthesized by a reproducible and inexpensive wet chemical method. The synthesized CuO nanoflowers were characterized by x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, field emission scanning electron microscopy and energy-dispersive spectroscopy. For an optimized operating temperature of 240°C, the sensor characteristics of the gas sensing device were measured using acetone as a volatile gas. The synthesized CuO nanoflower-based gas sensor responded very strongly for acetone gas concentrations in the range of 250–2250 ppm, and the recorded response for concentrations of 250 ppm and 2250 ppm was 2.7 and 7.2, respectively. The stability of the synthesized sensor was checked by repeating the measurements over a period of 1 month, and a very small change of 3.3% in the response of the sensor was observed.

Surface defects play a significant role in the nucleation and growth of metal particles. Site-selective nucleation of metal catalyst particles, and the subsequent growth of nanostructures, could thus be accomplished by defect engineering. This paper demonstrates the switching of growth sites of vertically aligned multiwall carbon nanotubes (MW-CNTs) by manipulation of surface passivation of the substrate and discusses the possible mechanism behind this selectivity. A complementary growth pattern of CNTs is observed for pre-treatment of identically patterned SiO2/Si substrates under a reducing and non-reducing atmosphere. Variation in the number density of oxygen vacancies on the silicon dioxide surface and the presence of native oxide on the silicon face are believed to dictate the observed selectivity. The CNT architectures mimic the substrate pattern meticulously, exhibiting sharp edges, illustrating a high degree of site selectivity. The chemical state of the substrate surface and catalyst particles has been studied using Auger electron spectroscopy. Electron microscopy and Raman spectroscopy were employed to characterize the synthesized CNTs. The Hermans orientation factor was calculated to quantify the degree of alignment of the MWCNTs. Such facile control over the growth site of aligned carbon nanotubes on a substrate is a desirable aspect of synthesis for easy integration with existing silicon fabrication technology.

This study was aimed to investigate the thickness dependent morphological changes of Mn films deposited on GaAs substrates by thermal evaporation technique. Ni films were deposited under same conditions to perform comparative study of the morphological changes with respect to the Mn films. The scanning electron microscopy and atomic force microscopy studies revealed ripple-shaped structure of Mn film with good periodicity, while Ni film only exhibited small granules deposited throughout the surface. The influence of the thickness of the Mn film in producing the ripple structure was clearly observed. In addition, the annealing time was considered as the major parameter to control the ordering of the ripple structure. X-ray diffraction pattern indicated the formation of different phases of Ga-Mn and Mn-As due to diffusion of atoms during annealing. A model for the creation of stress-driven microstructure is proposed which indicates that Mn thin films grow on GaAs substrates in three stages: in the primary stage, the growth occurs via two-dimensional nucleation process; as the thickness increases, the stress is released by the film via creation of additional surface roughness which produce ripples; and finally an island-like growth occurs because of the non-uniform distribution of stress along the surface of the film., Comment: Annealing; Atomic Force Microscopy; Manganese; Morphology; Scanning Electron Microscopy; Stress

Study Design: This was a retrospective cohort study.Purpose: This study investigated the influence of preoperative mental health on patient-reported outcome measures (PROMs) and minimal clinically important difference (MCID) among workers’ compensation (WC) recipients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).Overview of Literature: No studies have evaluated the impact of preoperative mental functioning on outcomes following MIS TLIF among WC claimants.Methods: WC recipients undergoing single-level MIS TLIF were identified. PROMs of Visual Analog Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), 12-item Short Form Physical and Mental Composite Scale (SF-12 PCS/MCS), and Patient-Reported Outcomes Measurement Information System Physical Function evaluated subjects preoperatively/postoperatively. Subjects were grouped according to preoperative SF-12 MCS

A unique V-shaped MnO

Supplemental material, sj-pdf-1-aan-10.1177_0218492321997084 for Minimally invasive (mini-thoracotomy) versus median sternotomy in redo mitral valve surgery: A meta-analysis of observational studies by Azhar Hussain, Jacob Chacko, Mohsin Uzzaman, Osama Hamid, Salman Butt, Saad Badar Zakai and Habib Khan in Asian Cardiovascular and Thoracic Annals

High-quality, ultrathin 2D- MoS2 layers with large area were grown on SiO2/Si substrates by using chemical vapor deposition (CVD) at elevated temperatures. The growth precursors (MoO3 and S) were placed separately inside the double zone furnace to control the growth parameters individually for better flexibility in the growth process. In this study, it was found that the shape and edge structure of the evolved MoS2 flakes were significantly influenced by the chemical potential of the Mo and S precursor concentration. In keeping with the concentration gradient of Mo precursor (MoO3) on the substrate surface, the shape of MoS2 flakes changed from hexagonal to truncated triangle and then to triangular shapes owing to the Mo-rich to S-rich conditions. The surface roughness and thickness of the differently shaped MoS2 flakes were studied by using an atomic force microscope (AFM). Additionally, Raman and photoluminescence (PL) techniques were employed to characterize the crystalline quality, a number of grown layers and optical performance of the as-grown MoS2 layers. Auger electron spectroscopy (AES) analysis and scanning electron microscopy (SEM) confirmed that the equilibrium crystal shape of the MoS2 was hexagonal under Mo rich conditions. However, the shape of the MoS2 crystal changed to a triangle under S rich conditions. Furthermore, the influence of chemical potential on the edge structure of the monolayer MoS2 and its effect on the equilibrium shape of the crystal were studied.

MnO2 nano-rods/flakes have been successfully synthesized by using a microwave-assisted hydrothermal method at 150 °C for 15 min at 400 W. The properties of synthesized materials have been analysed by the XRD, SEM, BET and electrochemical measurements. X-ray diffraction pattern of the as-synthesized powder confirms the formation of a phase pure MnO2 of a tetragonal crystal structure. The microstructure analyzed with SEM images describes nanorods and nanoflakes, which appear in self-assemblies of 70-100 nm diameter. A specific capacitance of 28.48 F g−1 at 0.4 A g−1 current density is achieved using MnO2 nanoflakes.

Fe filled carbon nanotubes were synthesized by atmospheric pressure chemical vapor deposition using a simple mixture of iron acetylacetonate with a conventional photoresist and the effect of growth temperature from 550 to 950 {\deg}C on Fe filled nanotubes has been studied. Scanning electron microscopy results show that, as the growth temperature increases from 550 to 950 {\deg}C, the average diameter of the nanotubes increases while their number density decreases. High resolution transmission electron microscopy along with energy dispersive X-ray investigation shows that the nanotubes have a multi-walled structure with partial Fe filling for all growth temperatures. The graphitic nature of the nanotubes was observed via X-ray diffraction pattern. Raman analysis demonstrates that the degree of graphitization of the carbon nanotubes depends upon the growth temperature., Comment: A. Nanostructures B. Vapor deposition C. Electron microscopy C. Raman spectroscopy C. X-ray diffraction

A high temperature chemiresistive ammonia sensor based on nanohybrids of semiconducting tungsten chalcogenides i.e. tungsten oxides (WO3) and tungsten sulfides (WS2) is reported in this paper. The sensitivity of the devices was investigated over a wide range of concentration i.e. (250–2000 ppm) and temperature (25 °C–400 °C). The sensor with composition of WO3/WS2 (70:30 wt.%) showed optimized performance when operated at 250 °C. The response of the sensor was found to be 1.5–12.6 times in the 250–2000 ppm range. The response and recovery times for 1000 ppm ammonia were found to be 160 s and 310 s, respectively. The sensor showed high selectivity towards ammonia over other volatile organic compounds, like ethanol, methanol, and acetone. The response from the sensor was found to be highly stable and reproducible over time. The plausible mechanism behind the excellent performance of the hybrid nanomaterial over the metal oxide based sensor suggests that the incorporation of transition metal dichalcogenides like WS2 could be beneficial for metal oxide based sensors in terms of lowering the operating temperature of sensing device, response enhancement, and improvement in the performance.

We examine the relationship between institutional investor ownership and dividend payouts using a large sample of NSE-listed non-financial firms during the period 2001 to 2016. Consistent with the evidence from the US market, institutional investors, on average, have larger holdings in dividend-paying firms and are seen to prefer dividend payers over non-payers among larger firms. However, among smaller firms, institutional investors seem to prefer non-paying firms. Consistent with it, logistic regression results reveal that institutional investors do improve a firms’ propensity to pay dividends, primarily across large firms. Further, among dividend-paying firms, institutional investors, on average, are observed to have relatively lesser holdings in firms with higher payouts than those with lower payouts. In line with these observations, regression analysis also provides no evidence to support a positive relationship between total institutional ownership and payout level. However, across investor categories, we do find evidence for domestic institutional investors (DII) in improving payouts. Further, we use a dynamic panel GMM estimator to correct for endogeneity and find that the relationship is robust among large firms. Our results highlight the role of DII in improving dividend payout and provide support to models that predict a positive relationship. JEL Classification: G23, G32, G34, G35

Polyaniline (PANI)/inorganic-nanomaterial based nanocomposites are attractive for gas sensing applications due to the synergistic behavior arising at their interfaces. In this work, HCl doped-PANI-nanofibers/WS2 nanosheet based nanocomposites were prepared by the template-free in situ polymerization of aniline on WS2 nanosheets, which were previously obtained by direct liquid exfoliation. The optimal performance was shown by the PANI/WS2 (w/w 10%) sample and it was characterized extensively using electron microscopy (SEM and TEM), several spectroscopic techniques (UV-Vis, Raman and FTIR), and X-ray diffraction. The nanomaterial was deposited on gold interdigitated electrodes which were then used as chemiresistive transducers for ammonia sensing at room temperature. The device was tested for ammonia concentrations of 50–200 ppm. The resistance of the device was found to increase with the concentration of ammonia vapours and a maximum response of up to 81% was recorded for 200 ppm of ammonia. The long-term stability, selectivity, sensitivity, and repeatability of the device were investigated. Apart from these, the device was also found to perform well under humid conditions. A mechanism based on the synergistic behavior due to the p–n heterogeneous characteristics at the interface of PANI and WS2 is proposed.

Polycyclic aromatic hydrocarbons (PAHs) showed significant seasonal dynamics in surface sediments of a tropical ecosystem (Cochin estuary, south west coast of India). Concentrations ranged from 304 to 5874 ngg − 1 in pre-monsoon, 493 to 14,149 ngg − 1 in monsoon, and 194 to 10,691 ngg − 1 in post-monsoon. The estuary was moderately contaminated with low molecular weight PAH fractions, which increased rapidly during the monsoon season indicating land/river runoff as the major transport pathway. The dominance of 2–3 ring fractions in the PAH indicated petrogenic and low temperature combustion processes as major sources, while the very low levels of 5–6 ring components indicated low contribution from pyrolytic sources. Low molecular weight fractions were higher in concentration than the Effective Range-Median (ERM) levels, whereas high molecular weight PAHs were lower than the Effective Range-Low values (ERL). Calculated carcinogenic toxicity equivalents (TEQ) values ranged from 1 to 971 ng g − 1 in the surface sediments.

This investigation deals with the effect of growth temperature on the growth behavior of Fe filled multiwalled carbon nanotubes (MWCNTs). Carbon nanotube (CNT) synthesis was carried out in a thermal chemical vapor deposition (CVD) reactor in the temperature range 650 to 950 1C using propane as the carbon source, Fe as the catalyst material, and Si as the catalyst support. Atomic force microscopy (AFM) analysis of the catalyst exhibits that at elevated temperature clusters of catalyst coalesce and form macroscopic islands. Field emission scanning electron microscopy (FESEM) results show that with increased growth temperature the average diameter of the nanotubes increases but their density decreases. High-resolution transmission electron microscopy (HRTEM) studies suggest that the nanotubes have multi-walled structure with partial Fe filling for all growth temperatures. The X-ray diffraction (XRD) pattern of the grown materials indicates that they are graphitic in nature. The characterization of nanotubes by Raman spectroscopy reveals that the optimized growth temperature for Fe filled CNTs is 850 1C, in terms of quality. A simple model for the growth of Fe filled carbon nanotubes is proposed., Comment: A1. Nanostructure A1. Growth model A1. Characterization A3. Chemical vapor deposition process B1. Carbon nanotube B1. Iron

A series of investigation were performed on Mn films which were deposited on GaAs substrates by thermal evaporation. The Mn films exhibit a highly ordered ripple-shaped structure with good periodicity, creating an exclusive patterning tool to construct two dimensional arrays of confined microstructures. The influence of the thickness of the Mn film in producing the ripple structure was clearly observed. In addition, the annealing time was considered as the major parameter to control the ordering of the ripple structure. A model for the creation of stress-driven microstructure is also proposed which indicates that Mn thin films grow on GaAs substrates in three stages: in the primary stage, the growth occurs via two-dimensional nucleation process; as the thickness increases, the stress is released by the film via creation of additional surface roughness which produce ripples; and finally an island-like growth occurs because of the non-uniform distribution of stress along the surface of the film.

In this work, cubic 3C-silicon carbide (beta-SiC) 1D-structures were successfully synthesized at various temperatures (1600 °C, 1650 °C and 1700 °C) by using graphite flakes and microfine silica through the carbothermal reduction process. The grown SiC structures were observed with two distinct morphologies viz. ribbon-type (diameter 2–5 µm) and rod-type (diameter ≤ 2 µm). The ribbon-type morphology was formed on the surface of the graphite flakes at relatively low temperature (1600 °C) whereas, the rod-type morphology was formed at a higher temperature (≥1650 °C) between the interlamellar spacing of graphite flakes. The TEM analysis confirms the growth direction of [111] for the as-grown 3C-SiC structures. The growth process of these two distinct morphologies is discussed in terms of nucleation and precipitation associated with vapour-solid (VS) and vapour-liquid-solid (VLS) mechanisms. Moreover, Raman spectroscopy indicated that the corresponding peaks of the as-grown SiC structures had red shifted as compared to the bulk SiC and that could be attributed to the confinement effect, internal stresses in the structure and stacking faults.

Gender history has a history proper to itself. This is not only to say that the study of gender as a scholarly and institutional practice is bounded by space and time, and that it has an archive of its own, but also that “gender history” as a relatively recent disciplinary innovation is properly gender history to the extent that it exists in relation to and distinct from other histories of becoming man, woman, trans, and so forth. In other words, gender history, regarded as a discursive formation in its own right, constitutes its object in ways that overlap but remain distinct from other conceptions of being and becoming gendered that are spatially and temporally diverse. Seen in this light, it can be said to map onto a history of sovereignty that has privileged particular forms of life and that acts as a limit on gender's analytical and critical value.

High-quality, ultrathin 2D-MoS2 layers with large area were grown on SiO2/Si substrates by using atmospheric pressure chemical vapor deposition (APCVD) at elevated temperatures. The growth precursors (MoO3 and S) were placed separately inside the double-zone furnace to control the growth parameters individually for better flexibility in the growth process. In this study, it was found that the shape and edge structure of the evolved MoS2 flakes were significantly influenced by the chemical potential of the Mo and S precursor concentration. In keeping with the concentration gradient of the Mo precursor (MoO3) on the substrate surface, the shape of MoS2 flakes changed from hexagonal to truncated triangle and then to triangular shapes, owing to the Mo-rich to S-rich conditions. The surface roughness and thickness of the differently shaped MoS2 flakes were studied by using atomic force microscope (AFM). Additionally, Raman and photoluminescence (PL) techniques were employed to characterize the crystalline quality, number of grown layers and optical performance of the as-grown MoS2 layers. Auger electron spectroscopy (AES) analysis and scanning electron microscopy (SEM) confirmed that the equilibrium crystal shape of the MoS2 was hexagonal under Mo-rich conditions. However, the shape of the MoS2 crystal changed to a triangle under S-rich conditions. Furthermore, the influence of chemical potential on the edge structure of the monolayer MoS2 and its effect on the equilibrium shape of the crystal were studied.

Classical models illustrate the genesis of bottom-up techniques for synthesis of pristine ZnO or Al-doped ZnO nanoparticles via surfactant aided or hydrothermal chemistry, to constitute the fundamental modules of nanotechnology and nanodevices. The present study demonstrates a facile as well as surfactant and catalyst free route for synthesis of morphology controlled Al-doped ZnO nanorods. Morphological evaluation (via FESEM and TEM characterization) clearly verifies the successful synthesis of ZnO and Al-doped ZnO nanorods. Moreover, crystallographic and FTIR studies ratified presence of multiple different planes as well as phases of ZnO and Al-doped ZnO nanostructures, eventually confirming the doping process. Further, the alteration in mode of electronic transition and surface charge of ZnO nanorods post doping with Al was witnessed from its UV–visible or photoluminescence spectra and zeta potential measurements, respectively. Electrical measurements were performed on prepared Al-doped ZnO nanorods which were fabricated as single nanorod devices. Owing to substitutional and interstitial doping, the electrical conductivity of the devices was drastically enhanced after doping. Excellent electrical attribute of the nanorods when fabricated into single nanorod device was indicative of its potential to be deployed as next generation nano-biosensors or piezo-electric devices.

Coronavirus Disease 2019 is a rapidly progressing pandemic that has affected 12.3 million individuals while causing 5,54,061 deaths worldwide till date. In India, approx 7,94,000 individuals (including approximately 4,96,000 recovered patients) have been affected with approximately 21,604 deaths. The sheer extent of the disease makes it imperative to increase awareness among our professional peers regarding the nature of the disease and its transmissibility while formulating standard operating procedures to mitigate the same. The present article disseminates the evidence to date and is based on available literature, brief working experiences, and relevant recommendations that can be implemented at various dental centers and units at all levels.

Manipulation in micro or nanoscale with robotic manipulators under observation of electron microscopes is a widely used strategy for fabrication of nanodevices and nanoscale material property characterization. These types of manipulation systems can handle the relatively larger scale of objects. However, the complexity of manipulation increases highly for 3D manipulation. Since the manipulation system consists of multiple components including manipulator, microscope, and also some end-effector tools, a proper offline visualization of the system is necessary for operation. Therefore, we propose a web-based virtual interface between the user and the actual manipulator operated under digital microscope initially. It gives the operator 3D positional feedback from the virtual model by mapping data read during remote operation. The same interface is used for remote operation of the manipulator within the SEM chamber and a manipulation task is performed.

We report the creation of chromium-coated optical fiber meta-tip using Focused-Ion-Beam Lithography. A 2D nano array is designed and fabricated on standard optical fiber tip and supports the localized surface plasmon resonance.

In this work, it has been demonstrated that for hydrophilic materials, like SiC, etc., superhydrophobicity can be achieved by coating them with a material like Au/Pd with surface adsorbed organic contaminants, rather than modifying them by fluoropolymers as is usually done. Dense and randomly aligned 3C-SiC nanorods were grown in a cold-wall APCVD reactor using Ni as a catalyst which formed a network of micro/nano air pockets and exhibited superhydrophobic behavior when modified by an Au/Pd metal alloy coating by forming hierarchical nanostructures with surface adsorbed organic contaminants. A high water contact angle (160°), very low sliding angle (

Fabrication of hierarchical nanostructures offers many advantages and can be exploited for creating superhydrophobic surfaces as well as heterojunctions and branched nanostructures, etc. In this work, catalytic growth of cubic-silicon carbide (3C–SiC) nanorods was carried out in an inductively heated horizontal cold-wall atmospheric pressure chemical vapor deposition (APCVD) reactor operated at the growth temperature i.e., 1200 °C for 1 h. Following this, hierarchical nanostructures of Au/Pd metal alloy were deposited on the surface of micron size long nanorods by DC sputtering. These hierarchical nanostructures were physically adsorbed on the surface of nanorods covering the exposed area. The average diameter of the nanorods as well as the average size of the adsorbed Au/Pd nanostructures was found to be in the range of 10–80 nm and 2–10 nm, respectively.

Graphene-carbon nanofiber (CNF) hybrid materials were synthesized by a simple one-step chemical vapour deposition method using propane over a Co 63 Ni 37 alloy catalyst supported on a silicon substrate at 800 °C. The process involves catalyst de-wetting, carbon diffusion and precipitation, with the additional carbon being provided by the polymer (photo-resist, HPR-504). The formation of a graphene-CNF hybrid structure was observed in the presence of the polymer. The polymer plays a crucial role in the formation of the flat carbon nanostructures. In the absence of the polymer, only carbon nanotube growth was observed with the same catalyst under identical experimental conditions. The effect of the polymeric photo-resist layer on the growth of the hybrid structure was analyzed. Structural and morphological data in combination with the Raman spectroscopic data confirmed the formation of a few layers of highly crystalline graphene and CNFs in a hybrid structure. The magnetic behaviour of these as-grown graphene-CNF hybrid samples has been analyzed by using a superconducting quantum interference device (SQUID). The results from the magnetic measurements on these samples have also been discussed.

In this study, a novel chemical vapor deposition (CVD) method for the mixed growth of random and self-aligned cubic (3C)-silicon carbide (SiC) nanorods was demonstrated in which the growth took place simultaneously via the VLS and VS mechanisms on the same Si substrate. The growth was carried out in an inductively heated horizontal cold-wall atmospheric pressure chemical vapor deposition (APCVD) reactor at 1200 °C for 1 h using a single source precursor i.e., hexamethyldisilane (HMDS) for both silicon and carbon and nickel (Ni) was used as a catalyst for the growth of 3C-SiC nanorods on the surface of Si (111) substrate via VLS mechanism while the self-aligned growth via VS mechanism was observed only at the cross-section of the same Si substrate facing the gas inlet end.

We describe a two step vertical growth of silicon nanowires (SiNWs) and the lateral growth of a bridging network of carbon nanotubes (CNTs) across the SiNWs. SiNWs were formed by an electro-less chemical bath deposition technique using silver nano particles as a virtual mask. Subsequently, the silver nano particles present on the side walls of SiNWs were used as a catalyst in the growth of CNTs by atmospheric chemical vapor deposition technique, forming “nano bridges”. A reduced reflectance of 65 % for the “nano bridge” samples compared to the SiNW samples was obtained suggesting a potential use in anti-reflection coatings.

A layer of a coumarin derivative\multiwall carbon nanotube (MWCNT) composite was sandwiched between an indium tin oxide (ITO) layer and a top metal electrode. This layer acted as the active hetero-junction (middle hetero-junction) in a triple hetero-junction organic solar cell. The composition of the organic material in the middle hetero-junction component, second from the ITO layer, was varied, keeping the weight percentage of the MWCNTs constant, to investigate the photovoltaic properties of the cell. The choice of amino-coumarin and its derivatives were dictated by the need for a high efficiency organic up-converter. Amino-coumarin is a two photon absorbing organic donor whereas CNTs are acceptors and ballistic charge transport media. For those reasons, amino-coumarin-CNT composite materials were selected as a photo active layer to will absorb the sub-band photons effectively. Additionally, the radial self-assembling of the CNTs inside the organic matrix (during synthesis) enhances the photovoltaic characteristics of the material. The photo induced charge transport mechanism between the MWCNTs and organics was analyzed using photo luminescence (PL) measurements. By the use of 15 wt% of CNTs with the organics, more than 90% of the PL signal was quenched, indicating an ultrafast transport mechanism between the donor and acceptor materials.

Vertically aligned carbon nanotubes (VA-CNTs) have been synthesized using high temperature catalyst nanoparticles of iridium. The catalyst layer was prepared by DC sputtering. Particle density, circularity and average particle size of the catalyst were analyzed using field emission scanning electron microscopy. The alignment, morphology and the length of the as-grown CNTs were analyzed using field-emission scanning electron microscopy. High resolution transmission electron microscopy was carried out to observe the layers of graphitic stacking which form the carbon nanotubes. Micro Raman measurement was used for the analysis of the graphitic crystallinity of the as-grown carbon nano structures. Effects of growth time variation on growth morphology and alignment have been studied. The alignment has been explained on the basis of the crowding effect of the neighboring nanoparticles.

Direct fluorination is one of the most important and effective method to modify the polymer surface. It isa simple and fast method that allows the simultaneous treatment of outer and inner surfaces of complex shapedpolymeric materials. Poly-p-phenylene terephthalamide fibers which are a very important class of material wassurface modified by direct fluorinaton. An extensive characterization of both the virgin and the fluorinated materialswere performed by various techniques (XRD, FT-IR, Surface energy and DSC, TGA). From these data, possibleeffects of fluorination are discussed. Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 230-235, DOI: http://dx.doi.org/10.14429/dsj.64.7321

Recently, two-dimensional (2D) molybdenum disulfide (MoS2) thin layers have been considered for the next generation optoelectronic devices, field effect transistors (FETs) and flexible electronics due to their flexibility, ultra-thin dimensions and excellent semiconducting properties. In this study, large area MoS2 mono-layers/ bi-layers/ tri-layers were grown on different types of substrates (SiO2/Si, Si) by chemical vapour deposition (CVD) technique. The MoS2 thin layers were synthesized at high temperatures (800 oC, 900 oC and 1000 oC) by using solid source precursors of molybdenum trioxide and sulphur in an argon atmosphere. The as-grown MoS2 thin layers were systematically characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) for phase analysis and to determine the surface morphology, respectively. Further, the thickness and surface roughness of the grown MoS2 thin layers were analysed by atomic force microscopy (AFM). Micro-Raman spectroscopy was used to identify the number of grown MoS2 layers and their crystalline quality. Finally, the electrical properties of the grown MoS2 thin layers were evaluated by using DC I-V measurements at room temperature in order to know the resistance of the grown layers.

International audience; The rate of exchange of urea across the membranes of human erythrocytes (red blood cells) was quantified on the 1-s to 2-min timescale. 13C-urea was hyperpolarized and subjected to rapid dissolution and the previously reported (partial) resolution of 13C NMR resonances from the molecules inside and outside red blood cells in suspensions was observed. This enabled a stopped-flow type of experiment to measure the (initially) zero-trans transport of urea with sequential single-pulse 13C NMR spectra, every second for up to ∼2 min. Data were analyzed using Bayesian reasoning and a Markov chain Monte Carlo method with a set of simultaneous nonlinear differential equations that described nuclear magnetic relaxation combined with transmembrane exchange. Our results contribute to quantitative understanding of urea-exchange kinetics in the whole body; and the methodological approach is likely to be applicable to other cellular systems and tissues in vivo.

We report a simple and inexpensive way for the preparation of highly transparent ZnO thin films and their application as active layer in UV ray sensor devices. ZnO thin films were deposited on glass substrates by thermal evaporation of pure ZnO powder. The as-deposited films were then annealed at different temperatures (100, 200, 300 and 400 °C) for various time durations (5, 15, 25 and 35 min) to make optically transparent in the visible region. The films annealed at 300 °C for 15 min show very good visible transparency and other material properties. These films were used as the active material for Ag/ZnO/Ag UV sensor devices. The sensor devices are photo conductive type and only sensitive in the UV region of the electromagnetic spectrum. Maximum photo-current gain of the UV sensor device is ∼2. Possible sensing mechanism has been discussed.