In this work the preparation of organic donor- acceptor thin films via physical vapor deposition is studied in theory and experiment. A chamber for organic molecular beam deposition was designed and integrated into an existing deposition system. Additionally, a load-lock, a chamber to prepare metallic contacts via stencil mask technique and a sputtering chamber were built. For the sublimation of organic compounds several effusion cells were constructed and the evaporation characteristics were compared to a simulation. The developed simulation program calculates the respective evaporation characteristics. It contains evaporation of particles, migration, and collisions in the gas phase. For the preparation and characterization of organic thin films it was focused on the charge transfer salt (BEDT-TTF)(TCNQ). Thin films were prepared by co-evaporation and studied with optical microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy (EDX). The formation of the monoclinic phase of (BEDT-TTF)(TCNQ) could be shown. As a last part complete devices (tunnel structures) were prepared and measured in a He4 cryostat.
Malaria remains a major cause of death and disability worldwide and is endemic to much of Africa, South America, and southeast Asia. Other malaria risk areas include the Middle east, some countries in Central America and Polynesia, with most other continents virtually free of the disease. The choice between RDTs and microscopy depends on local circumstances, including the skills available, patient case-load, epidemiology of malaria and the possible use of microscopy for the diagnosis of other diseases. Where the case-load of fever patients is high, microscopy is likely to be less expensive than RDTs, but may be less operationally feasible. Microscopy has further advantages in that it can be used for speciation and quantification of parasites, and to assess response to antimalarial treatment. Microscopy can also be used in the identification of other causes of fever. However, a major drawback of light microscopy is its requirement for well-trained, skilled staff and, usually, an energy source to power the microscope.
The development of composites using carbon fibers as the reinforcement requires surface activated carbon fibers with a durable surface composition. In this work, sized polyacrylonitrile (PAN)-based carbon bers were modi ed by Oxy- Plasma treatment, Oxy- fluorination, and Nitric acid treatment in order to improve the interaction between carbon ber surface and matrix. The effect of different surface treatments was observed by means of contact angle, surface free energy measurement. Surface roughness were seen by the help of Scanning electron microscopy (SEM).The lower contact angle proved the surface hydrophilicity of treated carbon fiber.XPS, Zeta-potential measurements revealed changes in surface chemistry of treated carbon fibers. The higher tensile strength of activated carbon fibers gave the assurance of more load bearing capacity of carbon fibers and also the acceptability of activation process.
Modern livestock producer employs artificial insemination (AI) using cryopreserved semen. The objective of this study is to determine the viability of sperms before and after cryopreservation. Semen collected from Bos taurus (4 Jersey cross and 8 Jersey pure breeds) was diluted to 80x106 sperms/ml, packed in 0.25ml French plastic straws and cryopreserved in liquid nitrogen. Microbial load assessment was performed to determine the quality. The present study aims at estimating the percentage of damage on the cryopreserved sperm by assessing Motility, Plasma Membrane and Acrosomal Integrity. Scanning Electron Microscopy (SEM) was carried out to study the plasma membrane and acrosomal damage more efficiently. Semen samples analyzed using Phase Contrast Microscope showed a decline by 30% after cryopreservation. The microbial load studies showed colonies within permissible limits. As observed in SEM, sperm integrity was found more in pre-freeze untreated semen samples.
In this paper, authors studied the impact of carbon steel coatings by functional epoxy resin TGEDA. The thickness of the deposited film on the substrate is estimated at 170 ± 10 µm. Firstly, to evaluate this impact of coating, the authors used two electrochemical methods: the stationary method using the polarization curve, the transient method based on the electrochemical impedance spectroscopy, and scanning electronic microscopy (SEM) were used in this study. The obtained results of this study showed that the corrosion current (icorr) is equal to 0, 07 µcm-2 and the polarization resistance (Rp) is equal to K .cm2.This shows that the effect of the investigated coating of carbon steel by the resin is more effective in 3 % NaCl compared to the uncoated one in the same medium. Subsequently, we conducted a new formulation by adding a series of inorganic fillers in the matrix of protection TGEDA/hardener (MDA), TEDA/MDA/load. The nature of the charges was 5% of zinc, 5% of trisodium phosphate and their mixtures.
Drilling with casing is among the top ten promising technologies to reduce well construction costs. It consists in using directly the casing as the drill string. Such a technique does not only reduces tripping time, but also decreases the risk of downhole problems and provides a safer working environment, all leading to an overall well construction cost cut by 30%.However casing connections were initially designed to withstand static tensile loads and have poor fatigue resistance properties. Intermediate solution was to use metal to metal seal buttress threads, which enable to drill down to 3,000 m with some success. The performances of these connections using thermo-chemical surface treatments have been investigated using a fit for purpose workbench, and promising results such as a 32% increase in admissible fatigue load, as well as an elastic limit of threads increase in 50%, have been observed. A complete fracture analysis was performed using Scanning Electron Microscopy (SEM).
This experimental work seeks to add to the understanding of fracture of ferroelectric ceramics. R-curve measurements with additional electrical loads show that AC electrical loading causes a drop in the critical mechanical load. The surface potential distribution around a stationary crack under various electromechanical loading conditions, measured with Kelvin Force Microscopy, is used to determine an effective dielectric constant of the crack, which is shown to depend on the distance from the crack tip, the electric and mechanical load and which changes with time and successive loading cycles.
In the last quarter century, delamination has come to mean more than just a failure in adhesion between layers of bonded composite plies that might affect their load-bearing capacity. Ever-increasing computer power has meant that we can now detect and analyze delamination between, for example, cell walls in solid wood. This fast-moving and critically important field of study is covered in a book that provides everyone from manufacturers to research scientists the state of the art in wood delamination studies.Divided into three sections, the book first details the general aspects of the subject, from basic information including terminology, to the theoretical basis for the evaluation of delamination. A settled terminology in this subject area is a first key goal of the book, as the terms which describe delamination in wood and wood-based composites are numerous and often confusing. The second section examines different and highly specialized methods for delamination detection such as confocal laser scanning microscopy, light microscopy, scanning electron microscopy and ultrasonics. Ways in which NDE (non-destructive evaluation) can be employed to detect and locate defects are also covered. The book's final section focuses on the practical aspects of this defect in a wide range of wood products covering the spectrum from trees, logs, laminated panels and glued laminated timbers to parquet floors. Intended as a primary reference, this book covers everything from the microscopic, anatomical level of delamination within solid wood sections to an examination of the interface of wood and its surface coatings. It provides readers with the perspective of industry as well as laboratory and is thus a highly practical sourcebook for wood engineers working in manufacturing as well as a comprehensively referenced text for materials scientists wrestling with the theory underlying the subject.
This volume examines the structure and dynamics of the bacterial flagellum using bacterial genetics, molecular biology, biochemistry, structural biology, biophysics, cell biology, and molecular dynamics simulation. The chapters are divided into 4 parts: Part I describes flagellar type III protein exports, assembly, and gene regulation in S. enterica, Part II explains how to isolate the flagella from the bacterial cell bodies, and further explains how to conduct high-resolution structural and functional analyses of the flagellar motor, Part III talks about how to measure flagellar motor rotation over a wide range of external load, how to measure ion motive force across the cytoplasmic membrane, and how to measure dynamic properties of the flagellar motor proteins by fluorescence microscopy with single molecule precision, and Part IV explores the structure and function of Spirochetal, Vibrio, Shewanella, and Magnetococcus flagellar motors. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.Cutting-edge and comprehensive, The Bacterial Flagellum: Methods and Protocols aims to provide valuable and vital research to aid in the investigation of the bacterial flagellum resulting from various bacterial species.