Статті в журналах з теми "Ultrafast Raman Loss Spectroscopic Studies"

Raman and FT-IR absorption spectra of aqueous tert-butyl alcohol (t-BuOH) and tert-butylamine (t-BuNH2) in the region of the O–H and NH2 stretching and bending modes have been measured as a function of organic co-solvent concentration in the whole co-solvent mole fraction region. The major observed changes of the aqueous binary solution spectra compared with the solvent spectra are a loss or gain of band intensity. In particular, the observed changes in intensities and linewidths of some bands were significantly more pronounced at low concentrations of organic co-solvents in water, where t-BuOH and t-BuNH2 tend to integrate into the water structure. Clear evidence of structural enhancement of the network is obtained in dilute solutions as well as destruction of the network by hydrophobic interactions as the concentration is increased. Generally, the interpretation of the spectra is in agreement with the capacity of the hydrophobic co-solvent to break the structure of water in the more concentrated aqueous solutions and to enhance the structure in dilute solutions. Vibrational intensities and frequency shifts of some bands show definite trends with varying the concentration of the solutions. In the concentration-dependence study, unusual linewidth changes of certain bands were observed.Key words: infrared, Raman spectra, aqueous, tert-butanol, tert-butylamine.

High-resolution hard x-ray spectroscopies (XES, HERFD, RIXS, XRS) are now well-established characterization tools for providing insights of material's electronic and geometric structure. The high brilliance synchrotron radiation beamlines have made feasible the routine study of the electronic structure and ligand environment of metal coordination compounds and active centers in metalloproteins, electrochemical process under in-situ conditions, as well as studies on catalytic systems under ambient conditions. Moreover, the recent availability of Linac Coherent Light Source (LCLS), provides some unique opportunities for the study of ultrafast electronic structure dynamics in various phenomena such as electron transfer processes, transient molecular states, molecular dissociation, etc. At SLAC National Accelerator Laboratory we have developed recently a set of high-resolution x-ray spectroscopic capabilities based on various multicrystal spectrometers. At SSRL we have built three multicrystal Johann spectrometers enabling XES/RIXS/HERDF techniques as well as X-ray Raman Spectroscopy. For LCLS, we have developed an energy dispersive multicrystal von Hamos spectrometer that records simultaneously the overall emission spectrum, enabling shot-by-shot time-resolved studies. Representative examples of application will be shown and discussed from the ongoing spectroscopy programs of SSRL and LCLS.

Raman and infrared spectroscopy are optical spectroscopic techniques that use light scattering (Raman) and light absorption (infrared) to probe the vibrational energy levels of molecules in tissue samples. Using these techniques, one can gain an insight into the biochemical composition of cells and tissues by looking at the spectra produced and comparing them with spectra obtained from standards such as proteins, nucleic acids, lipids and carbohydrates. As a result of optical spectroscopy being able to measure these biochemical changes, diagnosis of cancer could take place faster than current diagnostic methods, assisting and offering pathologists and cytologists a novel technology in cancer screening and diagnosis.The purpose of this study is to use both spectroscopic techniques, in combination with multivariate statistical analysis tools, to analyze some of the major biochemical and morphological changes taking place during carcinogenesis and metastasis in lymph nodes and to develop a predictive model to correctly differentiate cancerous from benign lymph nodes taken from oesophageal cancer patients.The results of this study showed that Raman and infrared spectroscopy managed to correctly differentiate between cancerous and benign oesophageal lymph nodes with a training performance greater than 94% using principal component analysis (PCA)-fed linear discriminant analysis (LDA). Cancerous nodes had higher nucleic acid but lower lipid and carbohydrate content compared to benign nodes which is indicative of increased cell proliferation and loss of differentiation.With better understanding of the molecular mechanisms of carcinogenesis and metastasis together with use of multivariate statistical analysis tools, these spectroscopic studies will provide a platform for future development of real-time (in surgery) non-invasive diagnostic tools in medical research.

We have constructed a broadband ultrafast time-resolved infrared (TRIR) spectrometer and incorporated it into our existing time-resolved spectroscopy apparatus, thus creating a single instrument capable of performing the complementary techniques of femto-/picosecond time-resolved resonance Raman (TR3), fluorescence, and UV/visible/infrared transient absorption spectroscopy. The TRIR spectrometer employs broadband (150 fs, ∼150 cm−1 FWHM) mid-infrared probe and reference pulses (generated by difference frequency mixing of near-infrared pulses in type I AgGaS2), which are dispersed over two 64-element linear infrared array detectors (HgCdTe). These are coupled via custom-built data acquisition electronics to a personal computer for data processing. This data acquisition system performs signal handling on a shot-by-shot basis at the 1 kHz repetition rate of the pulsed laser system. The combination of real-time signal processing and the ability to normalize each probe and reference pulse has enabled us to achieve a high sensitivity on the order of ΔOD ∼ 10−4–10−5 with 1 min of acquisition time. We present preliminary picosecond TRIR studies using this spectrometer and also demonstrate how a combination of TRIR and TR3 spectroscopy can provide key information for the full elucidation of a photochemical process.

In photosynthetic organisms, protection against photooxidative stress due to singlet oxygen is provided by carotenoid molecules, which quench chlorophyll triplet species before they can sensitize singlet oxygen formation. In anoxygenic photosynthetic organisms, in which exposure to oxygen is low, chlorophyll-to-carotenoid triplet–triplet energy transfer (T-TET) is slow, in the tens of nanoseconds range, whereas it is ultrafast in the oxygen-rich chloroplasts of oxygen-evolving photosynthetic organisms. To better understand the structural features and resulting electronic coupling that leads to T-TET dynamics adapted to ambient oxygen activity, we have carried out experimental and theoretical studies of two isomeric carotenoporphyrin molecular dyads having different conformations and therefore different interchromophore electronic interactions. This pair of dyads reproduces the characteristics of fast and slow T-TET, including a resonance Raman-based spectroscopic marker of strong electronic coupling and fast T-TET that has been observed in photosynthesis. As identified by density functional theory (DFT) calculations, the spectroscopic marker associated with fast T-TET is due primarily to a geometrical perturbation of the carotenoid backbone in the triplet state induced by the interchromophore interaction. This is also the case for the natural systems, as demonstrated by the hybrid quantum mechanics/molecular mechanics (QM/MM) simulations of light-harvesting proteins from oxygenic (LHCII) and anoxygenic organisms (LH2). Both DFT and electron paramagnetic resonance (EPR) analyses further indicate that, upon T-TET, the triplet wave function is localized on the carotenoid in both dyads.

In India, the thermal station generates approximately 6.9 × 10 7 tons of fly ash (FA) as a waste by-product. As part of this work, little attempt was made to produce useful materials from waste material. In our current research, polyaniline- (PANI-) fly ash (FA) nanocomposite (PFNC) was synthesized using an in situ polymerization method. The synthesized composites were characterized by employing advanced analytical, microscopic, and spectroscopic tools. The results of the X-ray diffraction (XRD) analysis confirm the effective reinforcement of FA into PANI in PFNC. The presence of functional groups in PFNC has been confirmed by Raman and FT-IR spectroscopic techniques. The SEM micrographs of the nanocomposite revealed the presence of agglomerated and fragmented structures in PFNC. The weight loss for PFNC was observed to occur in three stages as revealed by thermogravimetric analysis (TGA). UV-visible spectra for PFNC proved that FA stabilized the PANI in emeraldine form. Electrodynamic polarization studies were conducted to explore the corrosion resistance of nanocomposite-coated mild steel. The corrosion current density ( i corr ) for PFNC-coated mild steel (MS) specimens was found to decrease when compared to the bare substrate, indicating superior corrosion resistance in PFNC-coated substrate. Similarly, Tafel and cyclic polarization studies too confirmed superior anticorrosion property for MS coated with PFNC.

The formation of barium monomolybdate (BaMoO4) in inequimolar powder mixtures of BaCO3 and MoO3 was examined under isothermal and nonisothermal conditions upon heating in air at 25–1200 °C, using thermogravimetry. Concurrence of the observed mass loss (due to the release of CO2) to the occurrence of the formation reaction was evident. Accordingly, the extent of reaction (x) was determined as a function of time (t) or temperature (T). The x-t and x-T data thus obtained were processed using a well-established mathematical apparatus and methods to characterize the nature of the reaction rate-determining step and derive isothermal and nonisothermal kinetic parameters (rate constant, frequency factor, reaction order, and activation energy). Moreover, the reaction mixture quenched at various temperatures (450–575 °C) in the reaction course was analyzed by various spectroscopic (x-ray diffractometry, infrared spectroscopy, and laser Raman spectroscopy) and microscopic (scanning electron microscopy and x-ray energy dispersive spectroscopy) techniques for material characterization. The results obtained indicated that the reaction rate may be controlled by unidirectional diffusion of MoO3 species through the product layer (BaMoO4), which was implied to form on the barium carbonate particles. The nonisothermally determined activation energy (156 kJ/mol) was found to be close to the isothermally determined one (164–166 kJ/mol)

X-ray Raman scattering (XRS) spectroscopy is an inelastic scattering method that uses hard X-rays of the order of 10 keV to measure energy-loss spectra at absorption edges of light elements (Si, Mg, Oetc.), with an energy resolution below 1 eV. The high-energy X-rays employed with this technique can penetrate thick or dense sample containers such as the diamond anvils employed in high-pressure cells. Here, we describe the use of custom-made conical miniature diamond anvils of less than 500 µm thickness which allow pressure generation of up to 70 GPa. This set-up overcomes the limitations of the XRS technique in very high-pressure measurements (>10 GPa) by drastically improving the signal-to-noise ratio. The conical shape of the base of the diamonds gives a 70° opening angle, enabling measurements in both low- and high-angle scattering geometry. This reduction of the diamond thickness to one-third of the classical diamond anvils considerably lowers the attenuation of the incoming and the scattered beams and thus enhances the signal-to-noise ratio significantly. A further improvement of the signal-to-background ratio is obtained by a recess of ∼20 µm that is milled in the culet of the miniature anvils. This recess increases the sample scattering volume by a factor of three at a pressure of 60 GPa. Examples of X-ray Raman spectra collected at the OK-edge and SiL-edge in SiO2glass at high pressures up to 47 GPa demonstrate the significant improvement and potential for spectroscopic studies of low-Zelements at high pressure.

Abstract In this Part II of the paper on the evolution of carbon-rich Si–O–C polymer-derived ceramics (PDCs), emphasis is placed on the strengths and limitations of transmission electron microscopy (TEM) techniques with high lateral resolution, i. e., electron energy-loss spectroscopy (EELS), high-resolution TEM (HRTEM) and energy-filtered TEM (EFTEM). Here, the identical SiOC materials, as described in Part I. EELS studies confirmed the progression of structural rearrangements within the SiOC matrix temperatures exceeding 1200 °C. High-resolution TEM imaging showed that the SiOC matrices are indeed predominantly amorphous even upon high thermal treatment. Energy-filtered TEM analysis revealed, in contrast to the results obtained by Raman spectroscopy (Part I), that the excess free carbon phase undergoes a pronounced rearrangement within the amorphous microstructure. HRTEM characterization revealed the distribution of phases within the amorphous SiOC matrix; information that is not accessible by integral spectroscopic techniques. Discrepancies between the interpretation of experimental results obtained by local versus integral characterization tools are discussed in detail.

Lead zirconate titanate (PZT) is one of the most important piezoelectric materials widely used for underwater sensors. However, PZTs are hard and non-compliant and hence there is an overwhelming attention devoted toward making it flexible by preparing films on flexible substrates by different routes. In this work, the electrochemical deposition of composition controlled PZT films over flexible stainless steel (SS) foil substrates using non-aqueous electrolyte dimethyl sulphoxide (DMSO) was carried out. Effects of various key parameters involved in electrochemical deposition process such as current density and time of deposition were studied. It was found that a current density of 25 mA/cm2 for 5 min gave a good film. The morphology and topography evaluation of the films was carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively, which showed a uniform morphology with a surface roughness of 2 nm. The PZT phase formation was studied using X-ray diffraction (XRD) and corroborated with Raman spectroscopic studies. The dielectric constant, dielectric loss, hysteresis and I–V characteristics of the film was evaluated.

As multifunctional catalytic hemoglobins, dehaloperoxidase isoenzymes A and B (DHP A and B) are among the most versatile hemoproteins in terms of activities displayed. The ability of DHP to bind over twenty different substrates in the distal pocket might appear to resemble the promiscuousness of monooxygenase enzymes, yet there are identifiable substrate-specific interactions that can steer the type of oxidation (O-atom vs. electron transfer) that occurs inside the DHP distal pocket. Here, we have investigated the DHP A(V59W) mutant in order to probe the limits of conformational flexibility in the distal pocket as it relates to the genesis of this substrate-dependent activity differentiation. The X-ray crystal structure of the metaquo DHP A(V59W) mutant (PDB 3K3U) and the V59W mutant in complex with fluoride [denoted as DHP A(V59W-F)] (PDB 7MNH) show significant mobility of the tryptophan in the distal pocket, with two parallel conformations having W59-N[Formula: see text] H-bonded to a heme-bound ligand (H2O or F[Formula: see text], and another conformation [observed only in DHP A(V59W-F)] that brings W59 sufficiently close to the heme as to preclude axial ligand binding. UV-vis and resonance Raman spectroscopic studies show that DHP A(V59W) is 5-coordinate high spin (5cHS) at pH 5 and 6-coordinate high spin (6cHS) at pH 7, whereas DHP A(V59W-F) is 6cHS from pH 5 to 7. Enzyme assays confirm robust peroxidase activity at pH 5, but complete loss of activity at pH 7. We find no evidence that tryptophan plays a role in the oxidation mechanism ([Formula: see text]. radical formation). Instead, the data reveal a new mechanism of DHP inhibition, namely a shift towards a non-reactive form by OH[Formula: see text] ligation to the heme-Fe that is strongly stabilized (presumably through H-bonding interactions) by the presence of W59 in the distal cavity.

Tungsten trioxide (WO3) is a photocatalyst that has gained interest amongst researchers because of its non-toxicity, narrow band gap and superior charge transport. Due to its fast charge recombination, modification is vital to counteract this limitation. In this paper, we report on the fabrication of Mn-doped WO3/SnS2 nanoparticles, which were synthesised with the aim of minimising the recombination rates of the photogenerated species. The nanomaterials were characterised using spectroscopic techniques (UV-Vis-diffuse reflectance spectroscopy (DRS), Raman, XRD, photoluminescence (PL) and electrochemical impedance spectroscopy (EIS)) together with microscopic techniques (FESEM-EDS and high resolution transmission electron microscopy selected area electron diffraction (HRTEM-SAED)) to confirm the successful formation of Mn-WO3/SnS2 nanoparticles. The Mn-doped WO3/SnS2 composite was a mixture of monoclinic and hexagonal phases, confirmed by XRD and Raman analysis. The Mn-WO3/SnS2 heterojunction showed enhanced optical properties compared to those of the un-doped WO3/SnS2 nanoparticles, which confirms the successful charge separation. The Brunauer–Emmett–Teller (BET) analysis indicated that the nanoparticles were mesoporous as they exhibited a Type IV isotherm. These nanomaterials appeared as a mixture of rectangular rods and sheet-like shapes with an increased surface area (77.14 m2/g) and pore volume (0.0641 cm3/g). The electrochemical measurements indicated a high current density (0.030 mA/cm2) and low charge transfer resistance (157.16 Ω) of the Mn-WO3/SnS2 heterojunction, which infers a high charge separation, also complemented by photoluminescence with low emission peak intensity. The Mott–Schottky (M-S) plot indicated a positive slope characteristic of an n–n heterojunction semiconductor, indicating that electrons are the major charge carriers. Thus, the efficiency of Mn-WO3/SnS2 heterojunction photocatalyst was monitored for the degradation of chlorpyrifos. The effects of pH (3–9), catalyst loading (0.1–2 g) and initial chlorpyrifos concentration (100 ppb–20 ppm) were studied. It was observed that the degradation was purely due to photocatalysis, as no loss of chlorpyrifos was observed within 30 min in the dark. Chlorpyrifos removal using Mn-WO3/SnS2 was performed at the optimum conditions of pH = 7, catalyst loading = 1 g and chlorpyrifos concentration = 1000 ppb in 90 min. The complete degradation of chlorpyrifos and its major degradation by-product 3,5,6-trichloropyridin-2-ol (TCP) was achieved. Kinetic studies deduced a second order reaction at 209 × 10−3 M−1s−1.

AbstractAttempts to fabricate new CuIn1-xBxSe2 (CIBS) and CuBSe2 (CBS) thin-film materials have been complicated by the formation of interfering crystallites and by the loss of boron from the magnetron sputtered precursor alloys during the selenization and annealing processes. Raman and Auger spectroscopic analysis as well as x-ray diffraction studies show that the formation of boron selenide may be contributing to the difficulty in creating these new materials.

Abstract Purpose Antibody drugs are usually formulated as highly-concentrated solutions, which would easily generate aggregates, resulting in loss of efficacy. Although low pH increases the colloidal dispersion of antibodies, acid denaturation can be an issue. Therefore, knowing the physical properties at low pH under high concentration conditions is important. Methods Raman spectroscopy was used to investigate pH-induced conformational changes of antibodies at 50 mg/ml. Experiments in pH 3 to 7 were performed for human serum IgG and recombinant rituximab. Results We detected the evident changes at pH 3 in Tyr and Trp bands, which are the sensitive markers of intermolecular interactions. Thermal transition analysis over the pH range demonstrated that the thermal transition temperature (Tm) was highest at pH 3. Acid-treated and neutralized one showed higher Tm than that of pH 7, indicating that their extent of intermolecular interactions correlated with the Tm values. Onset temperature was clearly different between concentrated and diluted samples. Colloidal analyses confirmed the findings of the Raman analysis. Conclusion Our studies demonstrated the positive correlation between Raman analysis and colloidal information, validating as a method for evaluating antibody conformation associated with aggregation propensities.

AbstractMicro-Raman spectroscopic investigations of arsenic-implanted silicon show lines characteristic of silicon crystallites even at implant doses above the amorphization threshold. The intensity and frequency of occurrence of the lines increase with the implanted dose. Polarization/orientation Raman studies indicate the crystallites are silicon in the hexagonal phase (Si-IV) and silicon in the diamond phase (Si-I). The latter are oriented differently than the substrate silicon. Monte Carlo simulations of the arsenic ion energy loss and published molecular dynamics studies suggest that each arsenic ion deposits sufficient energy to locally melt the silicon lattice. This is taken as the basis of the present attempt to explain the origin of the crystallites. A one-dimensional numerical model is developed to determine the time scale for the liquid silicon to solidify. The effect of amorphous silicon on the solidification is also investigated.

ABSTRACTMicro-Raman spectroscopic investigations of arsenic-implanted silicon show lines characteristic of silicon crystallites even at implant doses above the amorphization threshold. The intensity and frequency of occurrence of the lines increase with the implanted dose. Polarization/orientation Raman studies indicate the crystallites are silicon in the hexagonal phase (Si-IV) and silicon in the diamond phase (Si-I). The latter are oriented differently than the substrate silicon. Monte Carlo simulations of the arsenic ion energy loss and published molecular dynamics studies suggest that each arsenic ion deposits sufficient energy to locally melt the silicon lattice. This is taken as the basis of the present attempt to explain the origin of the crystallites. A one-dimensional numerical model is developed to determine the time scale for the liquid silicon to solidify. The effect of amorphous silicon on the solidification is also investigated.

ABSTRACTLead strontium titanate (PbxSr1-xTiO3) (x=0.3–1.0) ceramic targets were prepared by the conventional powder-processing method. Thin films of these compositions were deposited on platinized silicon substrates by pulsed laser deposition technique. X-ray diffraction studies of the ceramic targets showed that the lattice structure changes from tetragonal to cubic phase with the increase of Sr content in PbTiO3. Raman spectroscopic studies of PbxSr1-xTiO3(PST) ceramics and thin films showed that the soft mode decreases to lower frequency and finally disappear at around 60–70 at% Sr content, which confirms the tetragonal to cubic phase transition at room temperature. Dielectric constant measured for PST thin films was in the range of 900–1500 at 1 MHz, with maximum value obtained for PST30 thin film. The loss tangents at room temperature were in the range of 0.07–0.1 for PST thin films with different compositions.

Abstract Single crystals of Na2La4(NH2)14·NH3 were obtained from supercritical ammonia under ammonobasic conditions at a temperature of 573 K and 120 MPa pressure. It represents a lanthanum-rich intermediate in the ammonothermal synthesis of LaN. Upon aging, the title compound loses the crystal ammonia, resulting in pale crystals of Na2La4(NH2)14, the original space group P212121 being retained in a very similar unit cell. However, the crystal structure reacts to subtle changes in the composition as well as to the modified coordination of particularly the sodium cations interconnecting lanthanum amide layers within a third dimension. Results of Raman spectroscopic studies are reported. The observations of thermal analysis measurements indicating the formation of lanthanum nitride, in combination with the observed retrograde solubility in liquid ammonia, contribute to the knowledge of the ammonothermal crystal growth of lanthanum nitride.

Electron energy loss spectroscopy (e.e.l.s.) provides an alternative method to infrared spectroscopy for studying the vibrational spectra of monolayers of chemisorbed molecules on single-crystal surfaces of metals. It has the advantages over infrared spectroscopy of considerably higher sensitivity, and the operation of two scattering mechanisms (dipolar and impact) that can be used to identify vibrations involving net motions parallel or perpendicular to the metal surface. It has the disadvantages with respect to infrared spectroscopy of lower attainable resolution and the necessity of the presence of only very low pressures (under 1 nbar) (0.1 m Pa) from molecules in the gas phase over the surface. Vibrational spectroscopy provides a powerful method for identifying the chemical structures of chemisorbed metal—adsorbate complexes. This is facilitated by an extensive existing vibrational spectroscopic literature. For work on metal surfaces, more recent infrared and Raman studies of ligands attached to metal clusters in com pounds of known structure have also been of substantial assistance. The scope of this type of surface analysis will be illustrated by a review of the extensive and interesting results now available by e.e.l.s. from this and a number of other laboratories for the adsorption of ethylene on a variety of metals and crystal faces, and over a range of temperatures. At low temperatures, ca. 100 K, ethylene adsorbs on different crystal faces as a π-complex or a di-σ adsorbed complex. At room tem perature, ca. 300 K , the low -tem perature species are transformed in some cases into an ethylidyne complex, CH 3 CM 3 (M = metal atom) or to a (C 2 H 2 )M 4 complex. More complex spectra, due to the presence of 4 different species, are obtained at room temperature by infrared transmission spectroscopy on finely divided oxide-supported metal catalysts. Three of these have been identified with the help of the e.e.l.s. results on metal single-crystal faces.

AbstractThe SiO2/TiO2/Nb2O5 material was set by the sol–gel method and was characterized by several techniques through thermogravimetric, spectroscopic, and textural analyzes. For the two synthesized materials, the specific surface area was 350.0 and 494.0 m2 g−1 (SiTiNb-A and SiTiNb-B, respectively). An enhance of the crystalline order with the temperature increase of the thermal treatment was observed. Through X-ray Photoelectron Spectroscopy analysis, the binding energy values for the Ti 2p and Nb 3d levels showed the insertion of Ti and Nb atoms in the silica matrix. The Electron Dispersive Spectroscopy analyses also confirmed the high dispersion of the metals presented on the materials surface. The Thermogravimetric Analysis showed weight loss for the of 37.6% (SiTiNb-A) and 29.7% (SiTiNb-B). The presence of the crystalline phases TiO2-anatase and monoclinic-Nb2O5 in the materials was confirmed through the data obtained by association of powder X-ray Diffraction and FT-Raman. Values obtained from optical band-gap aimed the dependence of the oxides concentration and the calcination temperature. Finally, the pyridine adsorption studies have indicated the presence of Lewis and Brønsted acid sites.

The aim of this special issue is to bring cutting-edge research across the entire spectrum of Materials Science and Nanotechnology. This special issue involves combining and understanding of the physical principles demonstrated by composite materials, nanomaterials, biomaterials, technology of nanometre-scale objects and other materials technologies. Materials engineering gathers scientists and engineers from many different subjects, such as materials science, nanotechnology, microtechnology, ceramic, metal, polymer, composite technology, and structural materials. This special issue allows researchers, academicians and professionals from across the globe to discuss, communicate and promote advances in knowledge, research and practice in the fields of Materials Science and Nanomaterials. This special issue contains the following titles: 1.1. Areca catechu as photovoltaic sensitizer for dye-sensitized solar cell (DSSC). This paper reports on the optical and photovoltaic properties of a new type of natural dye sensitizer from the Areca catechu (Pinang fruits) of Malaysia. In this study, it evaluated the solvent type effects on this dye's photovoltaic efficiency. Absorption analysis showed an excellent capacity to stabilize the dye. Fourier-transform infrared spectra revealed the presence of hydroxyl and carboxylic functional groups in the extracted dye, which were shown to be responsible for imparting the stronger electronic coupling and rapid electron transfer upon interaction with TiO2 surface. The spectral photoluminescence analysis of dye revealed that a broad photocurrent can be created by a narrowing bandgap. Results demonstrate that Areca catechu can be applied to DSSC. It is promising to achieve high cell efficiency, low-cost production and non-toxicity. 1.2. Preparation of natural rubber -OMMT nanocomposites using mechanical mixing and acid free co-coagulation methods: effect of processing method on mechanical properties. The development of rubber nanocomposites has been an area of scientific and industrial interest in the recent years, due to several improvements achieved in these materials. However, nanofiller like polar nanoclay is difficult to disperse in non-polar natural rubber, and hence it is difficult to achieve property improvements as expected by incorporating nanoclay using conventional rubber/latex processing methods. This paper introduces a novel method named acid free co-coagulation method stating from latex stage and in which a combined gelling agent was used for rapid gelation and the nanoclay was modified for enhancement of compatibility with rubber. The nanocomposites exhibited exfoliated clay structures with minimum clay aggregation, and remarkable mechanical properties. The new method will be used in the field of materials engineering, in future, to prepare rubber nanocomposites with different nanofillers. 1.3. Synthesis and characterization of single phase ZnO nanostructures via solvothermal method: influence of alkaline. The paper seeks to synthesize and characterize single phase zinc oxide nanostructures using simple basic and readily available equipment to achieve high quality nanostructures negating very complex routes. The method employed in this study could be reproduced easily without considering sophisticated equipment. Besides, the conditions adopted in producing the high purity zinc oxide nanostructures in this study are advantageous to the conservation of high energy used to achieve some of these outcomes in some studies. Unique findings from the morphological and spectroscopic results from this study could be applicable to fields in energy, electronics and pharmaceutical industries. It is the hope of every research scientist to develop simple techniques in material engineering to meet the growing demands of the technological world. 1.4. Effect of shrimp shell chitosan loading on antimicrobial, absorption and morphological properties of natural rubber composites reinforced with silica-chitosan hybrid filler. Rice husk and shrimp shells from agricultural waste were value added by using to prepare hybrid filler between rice husk silica and shrimp shell chitosan. Latex solution method was successfully applied to obtain natural rubber composites reinforced with this hybrid filler. The antimicrobial, absorption, and morphological properties of the natural rubber composite films and cured composites were investigated by the Agar Diffusion Method, Water Absorption Test and Scanning Electron Microscopy (SEM), respectively. All of NR composites with the addition of shrimp shell chitosan show antimicrobial activity. The addition of only 5phr shrimp shell chitosan in NR composite exhibits the most efficient E. coli inhibition and the absorption properties suitable for use as wound dressing. 1.5. The effect of viscosities of various coating solutions on the physical, mechanical and morphological properties of kenaf/epoxy composites. Natural fibres especially kenaf can exhibit excellent tensile properties. However, the actual potential of these fibres is commonly not achieved in fibre-reinforced composites due to low in dispersion, low compatibility and surface adhesion, and shape and stiffness inconsistency. This research aiming to provide a solution to the issues by employing a simple and practical coating treatment that suit macro-scale requirement of lignocellulosic industries. This manuscript explores the effect of various viscosities of coating treatment and the immersion time by analysing the maximum fibre-matrix interaction and composites deformation at a specific modulus and tensile Poisson’s ratio. The acetone’s amount used to change the viscosity play a vital role where the highest amount gave the optimum viscosity which able to overcome the issues and improved the overall composites’ properties. 1.6. Study of the magnetic properties of Zn doped Cobalt ferrite (CoZnxFe2-xO4). In this paper we studied the magnetic properties of Zn doped cobalt ferrite for different Zn concentration prepared by conventional solid state double sintering method. We observed the porosity of the samples using Scanning Electron Microscope. Magnetic measurement reveals that Curie temperature increases up to x = 0.1 then decreases for further concentration. We measured frequency dependent real and imaginary part of the permeability. From the measurement maximum quality factor and minimum loss factor were observed for x = 0.1. Magnetization curve shows that maximum value of saturation magnetization was observed for x = 0.1. These magnetic properties are useful for various applications such as high frequency devices, gas or humidity sensors etc. Our studies reveal that our produced samples may be useful for these kind of applications which are widely used in material engineering. 1.7. Silver nanoprisms/graphene oxide/silicon nanowires composites for R6G surface-enhanced raman spectroscopy sensor Surface enhanced Raman scattering (SERS) is an important analytical tool for the opto-chemical detection of molecules. The enhancement is commonly achieved by combining plasmonic nanomaterials with patterned or roughened supporting substrates of high surface area for increased light scattering and molecule adsorption. In this work, silicon nanowires (SiNWs) of different morphologies have been prepared by metal-assisted chemical etching technique. To produce highly sensitive and stable SERS devices, we have integrated graphene oxide (GO) layer sandwiched between the AgNPr and the SiNWs to serve as nanogaps and a protective coating for the silver nanoparticles from oxidation. High SERS response was demonstrated by AgNPr/GO/SiNWs compared to AgNPr/Si sensor for R6G detection. SERS efficiency of 6.1×〖10〗^10 was accomplished for AgNPr/GO/SiNWs composites. 1.8. Preparation and characterization of nanocellulose from sugarcane bagasse Nowadays, the demand for materials from renewable resources, such as biomass from agricultural wastes, to produce the desired materials are of grate interested. Nanocellulose is a natural nanomaterial which can be extracted from plant such as wood, flax, hemp, jute ramie, rice straws, coconut coir, cassava bagasse, corn cob, and sugarcane bagasse. This is due to renewable resources, environmentally friendly, low density, nontoxicity, and high biodegradability. The use of renewable resources as natural nanomaterials is one way of adding value to agricultural waste. Nanocellulose having low density greatly reducing erosion in the processing machine, safe for biodegradable and cheaper. It’s can be used as reinforcement material in several applications such as energy-harvesting materials, optical applications, printing applications, food packaging, and organic composite materials. In addition, nanocellulose has very good physical and chemical properties such as high strength, excellent stiffness, high modulus, low axial thermal expansion, and high surface area. In this study, nanocellulose particle was extracted from sugarcane bagasse by alkali and bleaching treatment for removed amorphous lignin and hemicellulose. Bleached cellulose was performed hydrolysis by sulfuric acid. The effects of hydrolysis time and temperature on particle size, chemical structure, crystallinity and thermal stability of nanocelluloses were studied.