Methanol-based Solution Research Articles

Abstract 6081: DNA integrity and preanalytical handling of endocervical samples for use in liquid biopsy-based diagnostics and monitoring of gynecological cancer

Abstract Background: Liquid biopsies from the gynecological tract can be useful for analysis of cell free DNA (cfDNA) (1, 2, 3). Sampling procedure and optimal preanalytical handling are poorly investigated. In this study, we aimed to evaluate how the profile and integrity of DNA, sampled from the female genital tract, were affected by preanalytical handling. Methods: Biobanked/archival (stored at -80℃ after 48h at room temperature (RT)) and freshly obtained clinical samples were analyzed together with standardized in vitro samples. Archival and in vitro samples were preserved in methanol-based solution, imitating clinical handling of endocervical samples which are initially stored at RT for 48h before further handling. The fragmentation profile of archival and in vitro samples was analyzed. Time series of in vitro samples at RT and 4℃, with extraction at 6-hour intervals from 0 to 96h, were performed. The fresh clinical samples were collected from the endocervix in methanol-based solution and from the vagina in a solution designed to preserve DNA and placed at 4℃ resp RT. Extraction was performed within 4h and at 48h. Results: Accumulation of short DNA fragments were observed in the archival samples and in the in vitro samples, indicating that fragmentation was initiated prior to 48h. Time series showed that the quantity of short DNA fragments gradually increased with time at both RT and 4℃ but at a slower rate in 4℃. At RT the percentage of fragments between 100-350bp increased 12-fold (0.39% vs 4.75%, p=0.002). The freshly obtained endocervical samples showed a similar significant increase in short fragments in samples stored at RT compared with samples stored at 4℃ (p= 0.02 for 100-230bp; p= 0.007 for 230-350bp; p= 0.03 for 100-2500bp) at 4h-48h. Conclusion: Pre-analytical handling of endocervical samples can be optimized. Lowering temperature from RT to 4℃ immediately haltered DNA fragmentation. Citation Format: Jacob Malchau Lauesgaard, Therese Carlsson, Anna Linder, Sara Schumacher, Karin Sundfeldt. DNA integrity and preanalytical handling of endocervical samples for use in liquid biopsy-based diagnostics and monitoring of gynecological cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6081.

Fabrication of efficient natural dye-sensitized Solar Cells using Mediterranean olive leaves as natural dye sensitizer

The synthesis of synthetic dyes employed in dye-sensitized solar cells (DSSCs) is often associated with substantial costs and environmental concerns. As a result, there is growing interest in utilizing natural dyes as sensitizers for DSSCs. This paper presents a comprehensive investigation into the extraction of natural dyes from Mediterranean olive leaves using a methanol-based solution, with a particular focus on the impact of different drying times during the dye extraction process on the efficiency of fabricated solar cells. The extracted olive leaf dyes were systematically characterized, encompassing their optical properties analyzed through ultraviolet–visible (UV–Vis) and Fourier Transform Infrared (FTIR) spectroscopy, electrochemical behavior, photovoltaic performance, crystallographic and morphological structures, as well as elemental composition. The research findings unveiled distinctive attributes of the olive leaf dyes, attributable to variations in their charge transfer processes to the band edge of the TiO2 semiconductor. These outcomes were substantiated through comprehensive analyses involving UV–Vis, FTIR, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Notably, the olive leaf dye subjected to a longer drying time (referred to as OLDS1) exhibited an energy level of the lowest unoccupied molecular orbital (LUMO) closer to that of the conduction band of TiO2, facilitating efficient electron transfer. Furthermore, X-ray photoelectron spectroscopy revealed alterations in elemental composition upon dye adsorption onto the TiO2 surface, with a notable reduction in the intensities of the Ti 2p and O 1 s peaks. The OLDS1 dye demonstrated lower charge transfer resistance and recombination rates compared to the shorter drying time for both fluorine-doped tin oxide (FTO) and indium-doped tin oxide (ITO)-based natural DSSCs (NDSSCs). Importantly, the choice of substrate material, specifically FTO and ITO, significantly influenced the NDSSC performance. The FTO/TiO2/OLDS1 configuration exhibited remarkable characteristics, including a high fill factor (FF) of approximately 0.73 and an efficiency of 0.31 %, accompanied by a short-circuit current density of 0.662 mA/cm2 and an open-circuit voltage of 0.642 V. These results highlight the crucial role of drying time and substrate selection in the fabrication of NDSSCs utilizing Mediterranean olive leaf extracts, with the FTO/TiO2/OLDS1 configuration emerging as the most promising and efficient combination.

Growth mechanism under the supply-limited regime in mist chemical vapor deposition: presumption of mist droplet state in high-temperature field

In mist CVD, investigation of the dependence of the growth rate on the solution concentration and precursor supply amount in the growth of ZnO films using a methanol-based solution of Zn(acac)2 revealed that the reaction is a rate-determination process of the supply-limited regime. Based on this result, the diffusion coefficient of gasified Zn(acac)2 at standard ambient temperature and pressure (SATP) was calculated to be approximately 10−6m2/s, where the diffusion rate was derived from the relation between the precursor supply amount and the film formation amount, assuming that all precursors were gasified in the reactor. The derived values were approximately one order of magnitude lower than the typical diffusion coefficient of 10−5m2/s in the gas phase at SATP. Several factors considered were unable to explain the much lower diffusion coefficient. Therefore, this result contradicts the assumption that all precursors are gasified in the reactor, and it is presumed that droplets might remain in the liquid–gas phase.

Co2+-Stuffed Quartz Solid Solutions With Zero Thermal Expansion Synthesized by Sol-Gel Spray-Drying

Glassy nanobeads of nominal composition CoO·Al2O3·4SiO2, doped with some Li2O to foster their crystallization, were synthesized by spray-drying from a methanol-based solution. Heat treatments at 850 °C and 900 °C successfully induced the formation of quartz solid solution crystals, whose thermal expansion was found to be very close to zero between 25 °C and 625 °C (average linear coefficient of thermal expansion CTE = 0.3 x 10-6 K-1). Annealing at higher temperatures induced structural unstuffing of the solid solutions, accompanied by the parallel formation of CoAl2O4 spinel and by a color shift of the powders from purple to blue. Sol-gel spray-drying stands out as a highly versatile synthesis method that can harness the thermal expansion tunability of quartz solid solution phases within a (quasi) lithium-free compositional landscape.

The effect of the electrolyte concentration on the charge transfer at the electrolyte/silicon-carbon interface: Electrochemical impedance spectrometry study

Silicon-carbon films were synthesized by electrochemical deposition from methanol/ethanol and hexamethyldisilazane solution. SEM studies have shown that samples with manganese and those obtained from the methanol-based electrolyte are distinguished by the presence of three-dimensional agglomerates on the surface, while the morphology of films obtained from ethanol-based solution is more uniform. Raman studies confirm the formation of silicon-carbon bonds and the effect of manganese addition on the film structure. Electrochemical behavior was studied using the Mott-Schottky analysis. The plots of all samples contain linear sections with both positive and negative slopes, which indicates n-type and p-type semiconductor behavior The highest charge carrier density was found in the “pure” silicon-carbon films obtained from the methanol-based solution. The Bode plots showed a mix of resistive and capacitive behavior and they do not change much with the type of the sample and electrolyte concentration.

Cu2ZnSnS4 films with Cu-poor composition prepared by spin coating from a nontoxic methanol-based solution: the effect of annealing temperature

ABSTRACT In comparison with the stoichiometry and Zn-rich/Cu-poor compositions of Cu2ZnSnS4 (CZTS) photovoltaic material, the properties of Cu-poor films have not been explored adequately. In this study, Cu-poor films were spin-coated from a non-hazardous methanol-based solution. Films were subject to a brief annealing process in the temperature range of 350–550 °C. As-grown and annealed films were uniform, compact, photosensitive, and free from secondary phases. As the annealing temperature increased, the size of crystallites increased and the film dislocation density decreased steadily. Films had a direct bandgap of 1.4–1.5 eV. The presence of three sub-bandgap transitions were detected and identified. By varying the annealing temperature, hole concentration, hole mobility, and film resistivity varied systematically in the range of 1016–1018 cm−3, 1–140 cm2/V-s, and 0.02–64 Ωcm, respectively. Cu-poor films showed structural and optoelectronic properties similar to the Zn-rich/Cu-poor and stoichiometric films and, thus, have the potential for device applications.

Sn-rich CZTS films spin-coated from methanol-based sol-gel solution: annealing effect on microstructure and optoelectronic properties

Photovoltaic light absorber Cu2ZnSnS4 (CZTS) with Sn-rich composition is the least studied compound compared with its stoichiometry and Zn-rich/Cu-poor compositions. Sn-rich CZTS films were prepared by spin coating from a nontoxic methanol-based solution. A brief (10 min) annealing in nitrogen was performed in the temperature range of 350–550 °C. The effect of annealing temperature on the film composition, morphology, crystallite size, microstrain, dislocation density, optoelectronic, and transport properties was investigated. For this study, scanning electron microscopy, x-ray diffraction, energy dispersive x-ray analysis, Raman spectroscopy, x-ray photoelectron spectroscopy, photocurrent spectroscopy, and Hall-effect techniques were employed. The annealed films were compact, uniform, and photosensitive. A systematic increase in the crystallites size and decrease in the microstrain and dislocation density was observed as the annealing temperature was increased. The films had a direct band gap energy of 1.47–1.50 eV. The presence of two sub-band gap direct transition energies of 1.04–1.08 eV and 1.16–1.21 eV were detected and their origins were discussed. Films were highly p-type in which the hole concentration increased systematically from 1.8 × 1018 to 1.5 × 1019 cm−3, and the hole mobility decreased steadily from 7.7 cm2/V-s to 0.94 cm2/V-s with the increase of annealing temperature. This behavior revealed that the ionized-impurity scattering is the dominant mechanism for the transport of holes in Sn-rich CZTS films. These highly p-type Sn-rich films have favorable properties suitable for device applications.

Biohydrogen production from pretreated sludge and synthetic and real biodiesel wastewater by dark fermentation

Different types of sludge pretreatments were tested, with thermal shock at 90°C to 95°C for 60 minutes plus a 6-hour rest period achieving the best results for inhibition of methanogen microorganisms and inoculum enrichment with H2-producing bacteria, which produced a H2-rich biogas (up to 65% mol/mol) without the presence of CH4. Wastewater from biodiesel production (WBP), containing mainly methanol (128 g/L) and glycerol (4 g/L), was evaluated as a potential substrate to produce H2 through dark fermentation. Both methanol-based solutions and methanol-rich wastewater were not suitable for hydrogen production; however, these effluents showed a strong potential for CH4-rich biogas production. A fractional factorial design was employed to evaluate the effect of six substrate-related variables (glycerol content, 25% and 75%; COD content, 4 and 50 g/L, COD:VSS ratio, 1:1 and 5:1; COD:N:P ratio, 350:0:0 and 350:5:1; NaCl content, 0.5 and 12.0 g/L; and pH, 4.0 and 5.5) on the H2 production from glycerol-methanol–based synthetic solutions (synthetic WBP). Some substrate-related variables had a crucial impact on the hydrogen production potential from WBP, which was significantly affected by the COD and salinity content in the substrate. WBP containing high glycerol (representing until 75% of the COD) and salinity (up to 12 g/L as NaCl) content could be turned into a potential substrate for H2 production through dark fermentation as long as specific fermentation conditions are maintained, such as pH 5.5 to 5.7 and a substrate COD content up to 50 g/L. Using this condition, glycerol conversion, H2 productivity, and H2 yield of 81.3 ± 8.9%, 102.8 ± 18.2 mL H2/L.d, and 24.5 ± 4.4 mL H2/g CODapplied, respectively, were obtained.

Stability study of veterinary drugs in standard solutions for LC-MS/MS screening in food

ABSTRACTA study on stability of veterinary drugs in standard solutions stored at −80°C and at −20°C was conducted over 1 year. Data were acquired on 152 individual stock standard solutions and also on 15 family mixes and 2 working standard solutions. All solutions were prepared, stored and compared 1 year later against freshly prepared ones by LC-MS/MS. A statistical analysis was performed to set the acceptability criteria, taking into account the variability of standard preparations. In individual stock standard solutions stored at −80°C (12 months) and −20°C (9 months), stability was demonstrated for 141 and 140 out of 152 compounds, i.e. for 92% and 93% of compounds, respectively. Drugs were even more stable when solubilised in either diluted family mixes or working standard solutions, with more than 99% and 94% of compounds found unaltered when stored at −80°C and at −20°C, respectively. In mixes, beta-lactams from the cephalosporin (cefadroxil and cephalexin) and penicillin (amoxicillin and ampicillin) families were found to be the least stable compounds when stored at −20°C (6 months), necessitating storage at −80°C to achieve a 1-year shelf life. The study also evidenced solubility issues for two sulfonamides (sulfadiazine and sulfamerazine) in methanol-based solutions. An independent stability study conducted by a second laboratory confirmed the 1-year stability of 3 family mixes—quinolones, sulfonamides and tetracyclines.

Applications of Solution Process for Li4SnS4-Based Solid Electrolytes to All-Solid-State Lithium-Ion Batteries

As the application of lithium-ion batteries (LIBs) has been expanded to large-scale systems such as electric vehicles and energy storage systems, their safety becomes the most important characteristic. However, conventional LIBs contain flammable liquid electrolyte which can cause serious safety concerns. In this regard, all-solid-state lithium-ion batteries (ASLBs) using inorganic solid electrolytes (SEs) are the most promising candidate to compete with the conventional LIBs. Especially, bulk-type ASLBs are considered to be highly competitive in terms of their potential for large-scale manufacturing, which is contrasted by high cost in vacuum-deposition-based fabrication for thin-film-type ASLBs. For the bulk-type ASLBs, inorganic sulfide SEs such as Li10GeP2S12 and glass-ceramic Li2S-P2S5 are appropriate because they show high ionic conductivity and deformability. The bulk-type ASLBs employing these sulfide SEs have demonstrated promising electrochemical performances.1 However, the severe discrepancy between the obtained performances and the expected ones from the extremely high conductivity values of sulfide SEs has been overlooked. The governing origin for this discrepancy is the poor ionic contacts in the composite electrode structures. As all components in bulk-type ASLB are solid, the surfaces of active materials are not fully covered by the SEs as far as the electrodes are fabricated by the mixing process.2 As efforts to circumvent this problem, direct coating of SEs by laser vapor deposition3 was reported. The laser vapor deposition technique should be, however, ruled out for scale-up because of the high cost. In this regard, development of the wet SE-coating process can be thus more attractive. However, the wet process for sulfide SEs has been hindered by instability of sulfide materials with solvents, which leads to too low ionic conductivity of the resulting precipitated materials. Also, the most sulfide SE with various solutions did not form coatable homogeneous solutions and the used solvents were not environmentally friendly. Recently, our group reported new solution processable SE, LiI-Li4SnS4, which was prepared from methanol-based solution. The resulting glass phase LiI-Li4SnS4 showed the high ionic conductivity of 0.41 mS cm-1 and the excellent dry-air stability.2 In this presentation, we will report facile electrode fabrication procedure employing the solution process of Li4SnS4, and its electrochemical performances will be presented. References Y. S. Jung, D. Y. Oh, Y. J. Nam, K. H. Park, Israel J. Chem. 55, 472 (2015). K. H. Park, D. Y. Oh, Y. E. Choi, Y. J. Nam, L. Han, J.-Y. Kim, H. Xin, F. Lin, S. M. Oh, Y. S. Jung, Adv. Mater. 28, 1874 (2016). A. Sakuda, A. Hayashi, M. Tatsumisago, Sci. Rep. 3 , 2261 (2013).

Solution-grown near-stoichiometry Cu2ZnSnS4 films: Optical transitions and defect levels

The preparation of device quality Cu2ZnSnS4 (CZTS) films by a simple and low-cost technique is of great importance for photovoltaic applications. In this work, stoichiometric films of CZTS could be synthesized by a successive dip coating method using a non-toxic methanol-based solution. The films' structure, composition, and surface morphology were studied by standard techniques. CZTS/CdS diodes with high rectification factors were fabricated and were used for electrical characterization of the films. The optical transmittance and photocurrent measurements were performed for optoelectronic characterization of the films. The results revealed the presence of two acceptor-type native defects with the activation energies of 114 meV and 300 meV. Five optical transitions were detected in the energy range of 1.34–3.2 eV and all could be identified on the basis of the two measured defect levels and the theoretical band diagrams of the stannite and kesterite structural phases of CZTS reported by Botti, Kammerlander, and Marques (2011). The results were in support of the co-existence of both structural phases in the films.

Cu2ZnSnS4 Films Grown on Flexible Substrates by Dip Coating Using a Methanol-Based Solution: Electronic Properties and Devices

The deposition of device quality Cu2ZnSnS4 (CZTS) films on flexible substrates by simple and cost-effective techniques is of great interest for solar cell applications. In this work, CZTS films were deposited on lightweight flexible substrates by successive dip coating using a nontoxic, methanol-based precursor solution. The films were characterized by x-ray diffraction, energy dispersive x-ray analysis, scanning electron microscopy, atomic force microscopy, optical transmission spectroscopy, photocurrent spectroscopy and admittance spectroscopy. The films prepared by this technique have direct band gaps of 1.5–1.6 eV, a p-type resistivity of ~1 Ω cm, an acceptor concentration of ~1017 cm−3 and structural and morphological properties that are suitable for device applications. Four defect levels with activation energies of 5.4 meV, 18.8 meV, 70 meV, and 221 meV were detected in the films. All but the shallowest defect level were attributed to the native VCu, CuZn, and VSn acceptor-type defects. For further assessment of the films, Schottky barrier and heterojunction diodes were fabricated and characterized. The results signified that the device quality CZTS films can be synthesized by the dip-coating method used in this study.

Prediction of Photovoltaic Cu(In,Ga)Se2 p-n Device Performance by forward Bias Electrochemical Analysis of Only the p-Type Cu(In,Ga)Se2 Films

This work is an attempt to rate the quality of Mo/Cu(In,Ga)Se2 films intended for fabrication of photovoltaic devices. The procedure is based on the simple current-voltage electrochemical analysis of the bilayer in a Eu2+/3+-containing electrolyte solution. Two series of bilayer samples were tested electrochemically, while sister samples were completed into Mo/Cu(In,Ga)Se2/CdS/i-ZnO/Al:ZnO/Ni-Al solid state devices and their current-voltage characteristics measured in the dark. A correlation was found between the reverse saturation current density of the solid state devices and an analogous parameter extracted from the electrochemical response in forward bias. While Eu2+ was found to be metastable in water posing restrictions to the application, reproducible measurements were achieved with a methanol-based solution. The intrinsic simplicity of the proposed methodology makes it particularly suitable for the implementation of a low-cost diagnostic tool.

Nanopillar array film of cellular cobalt by wet etching of the grain boundaries

In this work, a straightforward strategy was developed for the fabrication of cobalt thin films made of a dense array of vertically aligned nano and / or meso-crystals. Briefly, the proposed process consists in the electrodeposition of columnar cobalt thin films followed by a selective wet-etch treatment. Based on a preliminary screening of either aqueous or methanol based acid etchants, either a nitric acid or methanesulfonate methanol solution was further considered. The degree of selectivity of the etching solutions was evaluated on the basis of the observation of film surface/cross section morphology before and after etching. Contrary to water-based solutions, methanol-based solutions showed definitely a degree of selectivity toward grain boundary preferential etching. In particular, with methanesulfonic acid (MSA)- methanol solution, saturation of the etchant with oxygen was found to have a profound effect in improving the control of the etching process. Accordingly, an 11.2% methanol-based MSA solution was able to selectively etch the Co layer at the grain boundaries, leaving Co individual crystals separated by nanochannels.

Quercetin-imprinted chromatographic sorbents revisited: Optimization of synthesis and rebinding protocols for application to natural resources

Molecularly imprinted polymers (MIPs) based on quercetin and synthesized by either bulk, precipitation or suspension polymerization were characterized in terms of size and shape by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After a study of rebinding protocols, the optimal materials were evaluated as sorbents for solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) to confirm the presence of imprinted cavities and to assess their selectivity. Besides quercetin, other structurally related natural compounds, naringenin, daidzein and curcumin, were employed for selectivity tests of MIPs. Although rebinding protocols previously described for such MIPs are typically based on binding, washing and eluting methanol-based solutions, we show that this highly polar solvent leads to weak specific interactions (imprinting factor<1) and poor sorbent properties, most probably because of hydrogen-bonding interferences between the MIP and MeOH. Similar experiments performed in tetrahydrofuran yield to much more improved properties (imprinting factor>2.4). This calls for reviewing most of previously published data on quercetin-MIPs; in proper binding conditions, published MIPs may prove more performing than initially assessed. As expected, tested MIPs exhibited the highest selective rebinding towards quercetin template (imprinting effect, quercetin, 3.41; naringenin, 1.54; daidzein, 1.38; curcumin, 1.67); the differences in selectivity between quercetin analogues were explained by the ligand geometries and H-bonding patterns obtained from quantum-chemical calculations. The evaluation of MIPs under identical analytical conditions allowed investigating the effect of the production method on chromatographic performances. The MIPs in bead materials (for quercetin, peak width, 0.69; number of theoretical plates, 143; symmetry factor, 2.22) provided a significant improvement in chromatographic efficiency over the bulk materials (for quercetin, peak width, 1.25; number of theoretical plates, 115; symmetry factor, 2.92). Using the quercetin-beaded MIP as SPE sorbent, quercetin was selectively extracted from Allium cepa L. extract. The MIP developed in this work therefore appears highly promising for the enrichment and determination of quercetin in natural products.

TiO2 flower-like nanostructures decorated with CdS/PbS nanoparticles

Flower-like nanostructures of TiO2 were prepared by immersing Ti foil in 30% H2O2 at 80°C for times varying from 15 to 240min. Upon annealing at 450°C in an Ar atmosphere, the received amorphous samples crystallized in an anatase structure with rutile as a minority phase. SEM images revealed that partially formed flowers were present at the surface of the prepared samples as early as after 15min of immersion. The size of the individual flowers increased from 400–800nm after 15min of reaction to 2.5–6.0μm after 240min. It was also found that surface is very rough and surface development is considerable. After 45min of immersion, the nanoflowers were sensitized with CdS and PbS quantum dots (QDs-CdS/QDs-PbS) deposited using the SILAR method from water- and methanol-based precursor solutions at different concentrations (0.001–0.1M). QDs-CdS crystallized in the hawleyite structure, while QDs-PbS in the galena form. SEM analysis showed the tendency of quantum dots to agglomerate at high concentrations of the precursor in water-based solutions. QDs obtained from methanol-based solutions were uniformly distributed. The produced QDs-PbS were smaller than QDs-CdS. Based on the optical reflectance spectra, the band-gap energies of TiO2 nanostructures with and without QDs were calculated to be 3.32eV for flower-like TiO2 nanostructures and 2.35eV for QDs-CdS. The photoelectrochemical behaviour of nanoflowers was found to improve significantly after the deposition of QDs-CdS.

Templated Self-Assembly of ZnO Films on Monolayer Patterns with Nanoscale Resolution

Lithographically defined self-growing ZnO films were prepared by a bioinspired chemical bath deposition technique (CBD). We observed a high selectivity of ZnO deposition: Teflon-like per-fluoro-decyl-trichlorosilane (FDTS) monolayers repelled ZnO primary particles, whereas amino-functionalized areas of the substrate were selectively covered by a highly anisotropic, oriented, and compact ZnO film with a thickness of 50 nm. The size of the primary particles in our methanol-based solution was approximately 2.5 nm. On the amino substrate they formed agglomerates not larger than 30 nm. Monolayer patterns made by polymer blend lithography were templated with an edge resolution of 30 nm. By using a specialized derivative of microcontact printing, we prepared layout-defined silane templates, which reliably determined the growth of a layout-defined, patterned oxide film with submicrometer lateral resolution.

Silane solution stability and film morphology of water-based bis-1,2-(triethoxysilyl)ethane for thin-film deposition on aluminium

Thin-film silane coating (<1 μm) has been introduced as a chromium free multi-metal surface pre-treatment for corrosion protection, adhesion promotion and surface passivation of metals such as aluminium, steel, zinc, magnesium and others. Bis-1,2-(triethoxysilyl)ethane (BTSE) has received much attention as it is, after hydrolysis, highly reactive towards (covalent) metal/film bonding and cross-link formation for the creation of barrier properties. Much of the past work on BTSE was performed on methanol-based laboratory solutions due to the low solubility of BTSE in water. For industrial applications these solutions are not considered suitable anymore because of the high process cost as well as ecological and health issues associated with methanol and the high monomer content of such solutions. For industrial practice water-based silane solutions are being considered. In the present work water-based BTSE solution is compared to a reference methanol-based solution. The silane solution is analysed using 29Si NMR spectroscopy, and the deposited silane films are morphologically characterised using infra-red spectroscopic ellipsometry and field-emission gun-scanning electron microscopy.

The deformation and fracture of a dual-phase intermetallic alloy

Ordered intermetallic alloys possess many attractive properties, yet their use as a structural material has been severely limited by a general lack of low temperature ductility. The beta/gamma-prime dual-phase Ni50Fe30A120 (atomic percent) intermetallic alloy has shown remarkable ductility, exhibiting fracture strains in excess of 20% in both tension and compression. This behavior is yet unexplained, thus an investigation was conducted to study the deformation and fracture behavior of this alloy.The material studied was a Ni50Fe30A120 (nominal composition) directionally solidified alloy. TEM specimens were made from the as cast material in an unstrained condition and with a 1% strain in compression. The foils were hand ground to a thickness of about 75 um and electrothinned in a Tenupol twin jet polisher with a methanol-based solution containing 2% perchloric acid and 35% butyl cellosolve at -20C. A JEOL 2000 FX AEM was used to examine the strained and unstrained foils. STEM microanalysis was performed on the unstrained foil with a Phillips CM-12 AEM to determine the composition of the two phases. Finally, the compression fracture surface was studied using a Hitachi S520 SEM.