····· lezzter Preis 26.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray El oxido de zinc (ZnO) es un mineral complejo con propiedades fisicoquímicas unicas que lo hacen fascinante desde un punto de vista científico, en película delgada presentan una baja resistividad y una transmitancia en el visible alrededor de un 80 %. Esto se debe a la microestructura de la película, la cual esta restringida por los procesos termodinámicos que se llevan a cabo durante su fabricación, su impurificación y la importancia de la concentración del ácido acético glacial en su fabricación para controlar las propiedades eléctricas, ópticas y morfológicas. Este libro describe las técnicas que se utilizan para caracterizar las películas delgadas de ZnO:In. con el propósito de conocer la variación de las propiedades físicas en función de los parámetros de deposito ····· 1036124071
····· lezzter Preis 53.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray La fotocatálisis heterogénea, que pertenece al grupo de las denominadas Técnicas Avanzadas de Oxidación (TAOs), es muy utilizada en el tratamiento de aguas contaminadas donde es muy reconocido el uso del óxido de titanio, fase anatasa, semiconductor que ha dado buenos resultados en la fotodegradación de moléculas orgánicas. Entre otros sistemas que, según la literatura, pueden presentar las propiedades de fotocatálisis heterogénea se encuentran los óxidos de cinc (ZnO con energía de gap Egap=3,2 eV y longitud de onda =388nm) y de estaño (SnO2). En este documento se indican los principales resultados que se obtuvieron de la síntesis y caracterización de los polvos nanométricos de óxido de cinc (ZnO), y del óxido de cinc dopado con óxido de estaño (ZnO/SnOx), obtenidos por precipitación controlada, y su posterior empleo para propiciar reacciones de fotodegradación, a una solución de azul de metileno, con el fin de determinar su capacidad fotodegradante. ····· 1036123810
····· lezzter Preis 80.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray El tema global de este estudio se enmarca en la disminución de la contaminación, a través de la reutilización directa de los baños de tintura de poliéster con colorantes dispersos. La investigación se desarrollará teniendo en cuenta principalmente la influencia que tiene la reutilización sobre la calidad del producto, entendiéndose por ésta las diferencias de color que presenta el sustrato teñido con un baño de reutilización respecto del que fue teñido con el baño inicial. Un caso especial dentro de las fibras de poliéster es el de las microfibras, debido a que éstas al poseer mayor área específica requieren de mucha mayor cantidad de colorante que una fibra convencional. Las fibras de poliéster se tiñen exclusivamente con colorantes dispersos, los cuales aunque poseen un buen agotamiento, al final del proceso de tintura, queda en el baño la suficiente cantidad de colorante para no ser despreciado y podría ser utilizado sin restricción alguna para el siguiente ciclo de tintura. ····· 1036122742
····· lezzter Preis 62.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Los manantiales kársticos contienen altas concentraciones de dureza disuelta originada en la disolución de las formaciones geológicas carbonatadas que limitan la utilización de los recursos hídricos en estas zonas geográficas. En tal sentido, el estudio integral de los sistemas kársticos y la identificación de los procesos naturales de ablandamiento resulta fundamental para definir, en primera instancia, la calidad del agua de estas fuentes y, por ende, realizar un planteamiento eficaz con mecanismos de ablandamiento no convencionales. Este libro presenta el desarrollo y la adecuación metodológica para la reducción de la dureza de las aguas carbonatadas, con fundamento en el aprovechamiento y la optimización de los mecanismos naturales de ablandamiento y los mecanismos de sorción. Los capítulos abordan secuencialmente el contexto carbonatado del karst, desde su génesis y caracterización hidroquímica, hasta la remoción de la dureza disuelta con la ejecución de pruebas experimentales que culminan la síntesis teórica con una propuesta de ablandamiento a nivel piloto, ofreciendo una contribución al estudio de los factores controladores de la dureza del agua en áreas kársticas. ····· 1036122311
für 62.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray El avance tecnológico en los procesos de deshidratación ha llevado al estudio de técnicas para la obtención de productos de calidad que al mismo tiempo contribuyan con la reducción del consumo energético a través del mejoramiento de la eficiencia de los procesos y equipos. Uno de los procesos donde se persiguen tales intereses es el secado por aire caliente ya que, además de ocupar un importante lugar en la transformación de productos agroalimentarios y en los sistemas de tratamiento poscosecha, es una de las actividades industriales que supone mayor consumo energético. En tal sentido, la tecnología del secado intermitente ha sido empleada con el fin de disminuir el tiempo de calentamiento, preservar la calidad y minimizar el consumo energético en el secado de materiales sensibles al calor y donde la cinética está controlada por mecanismos de transferencia internos. El presente trabajo es una contribución al estudio y optimización del secado intermitente en productos hortofrutícolas a través de la aplicación de técnicas de modelización matemática y simulación computacional, con el fin de mejorar la eficiencia energética del proceso. ····· 1036122070
für 26.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Se estudio la transición del electrolito sólido NaI-AgI, mediante medidas de conductividad eléctrica. Aunque el NaI no se disuelve en AgI, al agregar NaI se produce una estabilización de la temperatura de transición del AgI a 420 K, un salto en la conductividad iónica del AgI y una diferencia entre los valores de la conductividad en las fases y del AgI. La magnitud del cambio en el número de portadores en la conductividad a 420 K mostró una variación durante la transición. Los datos de la conductividad se analizaron considerando que la densidad de transporte iónico es la principal causa del aumento espontáneo en la conductividad iónica a través de la transición de este electrolito sólido. Por lo tanto, al proponer un modelo de densidad de energía libre para la concentración de defectos en equilibrio es posible reproducir los cambios observados en NaI-AgI a 420 K. ····· 1036121807
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Conductive polymers are organic compounds that conduct electricity. Such compounds may be true metallic conductors or semiconductors. It is generally accepted that metals conduct electricity well and that organic compounds are insulating, but this class of materials combines the properties of both. The biggest advantage of conductive polymers is their processibility. Conductive polymers are also plastics (which are organic polymers) and therefore can combine the mechanical properties (flexibility, toughness, malleability, elasticity, etc.) of plastics with high electrical conductivities. Their properties can be fine-tuned using the exquisite methods of organic synthesis. Different additives are usually added to polymer in order to modify and improve its properties. Inorganic additives such as transition metal salts have considerable effect on the optical and electrical properties of polymers. ····· 1036121554
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Coumarins have attracted intense interest in recent years because of their diverse pharmacological properties. Among these properties, their cytotoxic effects were most extensively examined, their broad range of effects on the tumors as shown by various in vitro and in vivo experiments. Coumarins have important effects in plant biochemistry and physiology, acting as antioxidants, enzyme inhibitors. In addition, these compounds are involved in the actions of plant growth hormones, growth regulators, the control of respiration and photosynthesis. Coumarin derivatives have also found applications as fluorescent dyes, anti-inflammatory agents, antineoplastic agents, antifungals, anticoagulants, antibacterial, antimicrobial, insecticides, hepatoprotective and anti HIV activity. Therefore, the kinetics of the base hydrolysis of some coumarin derivatives were studied in aqueous solution and aqueous-co organic media at different temperatures.Moreover, the transfer chemical potentials of the investigated compounds were calculated from solubility data to give an overall idea of solvent effects on reactivity. ····· 1036120869
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray The electrochemical behavior of tin, indium and Sn-In alloys in 0.5 M solutions of oxalic, Malic and citric acids at temperature 30-60 oC was studied by Potentiodynamic technique. The results showed that the peak height and corrosion rate increase with increasing the temperature. The corrosion of tin, indium and Sn-In alloys is affected by the formation of soluble complex species with organic acid anions and the order of decreasing aggressiveness is oxalic malic citric acid. The corrosion rate of Sn-In alloys also affected by percentage of In in the alloy. Where In form two phases alloys with Sn ( and phase), these results were confirm with X-ray diffraction. The corrosion inhibition of tin, indium and their alloys in aqueous acidic solutions in presence of Adenine, Adenosine and 2, 4, 6 tris (2pyridyl)-1, 3, 5-triazine (PYT) as corrosion inhibitors was studied. ····· 1036120855
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Low cost agricultural waste material and animal bones were utilized for the preparation of activated carbon. Industrial spent carbon was also regenerated. The carbon samples were activated chemically and by thermal means (400-1000°C). The samples were characterized by surface area (BET, DR, BJH, Langmuir) with pore volume, FTIR, XRD, SEM and EDS. The rate of adsorption of dyes on the carbon samples was high in the initial fifteen seconds and then declined due to its diffusion in to the micropores. Negative values of entropy of activation ( S) of the dyes adsorption reflected the affinity of the dye molecules towards the carbon surface which were found to decrease with the increase in adsorption temperature. The linear plots of Bangham and intraparticle diffusion models showed that the adsorption of dye on the carbon surface is a diffusion controlled process. The Freundlich, Langmuir and DR models were used to estimate the adsorption parameters. The best fit of the isotherms, found from the correlation coefficients (r2) were in the sequence: DR Langmuir Freundlich. ····· 1036120748
····· lezzter Preis 49.90€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Enormous progress has been made in the field of materials science, it is still many technological challenges, including the development of materials and taking into account the social and environmental impact of their production and use. In this work, the surface treatments of steels are exposed using an accessible and clear terminology. Treatment methods are explained in detail. An example of a plasma nitriding treatment was introduced this treatment was carried out under different conditions. This book is intended for students and researchers in post graduation. ····· 1036120600
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Quantum chemical calculations are based on optimizing parameters including the basis set in order to obtain the best possible results. Applying the subroutines with analytical derivatives instead of numerical derivatives leads to decrease the number of iteration steps through the direct optimizing process. All the components of the first and second derivatives with respect to all parameters can be derived analytically and programmed. Evaluation of the correct structure for molecules is the main goals of the computational chemistry coding to introduce new methods. The correct description of the lone pair electrons can predict the electronic properties which can be compared to experimental values by using many models based on FSGOs. Reading the book, you will learn: a- Detailed mathematical techniques to evaluate and computerize the exact expression for analytical derivatives of a simple kind of the molecular orbital descriptions like as the explicit expression of total energy in FSGO method, b- Applying simplified PV-RR method for Hydrogen and LiH molecules using the basis set obtained by DFSGO method, and c- The correct description for lone pair orbitals in some cyclic compounds. ····· 1036120486
für 53.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Metals have an impact on human health in many ways. Some elements are essential micronutrients with a human requirement of no more than a few milligrams per day. However, micronutrients may become harmful when their ingestion rates are too high. Some elements are likely to be essential micronutrients, although their positive role in human nutrition. Trace elements are well known as toxic if their intake through ingestion or inhalation is excessive. ····· 1036120271
für 61.20€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Metals and alloys are universal in their use. They are the most promising engineering materials for the construction and fabrication. Especially zinc and steel are the important materials that have numerous applications. While in use, they are exposed to various aggressive media and undergo corrosion.Many of the corrosion problems generated in the industries involve the surroundings associated with acids, alkalies and solvents. Due to the rapid growth in different sectors, the contamination of the environment is unavoidable. Thus corrosion process is continuous and irreversible. A number of methods are available to control corrosion of materials. The use of inhibitors is one of the simplest and practical methods generally employed to control corrosion of steel and zinc. Corrosion inhibitors are the chemicals that interact either physically or chemically with a metal surface or the environment to which the metal surface is exposed. Inhibitors are used in a wide range of applications such as oil pipe lines, central heating systems, industrial water cooling systems, acid pickling and metal extraction plants. it also added to coolant, fuels, hydraulic fluids, boiler water and etc. ····· 1036119947
für 49.41€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Over the last few years, the price of the fuel is the main factor affects the consumption and the economy. Even when crude oil prices are stable, the fuels prices normally fluctuate. Additionally, diesel engines are considered a major source of air pollution in cities and urban areas because of their black smoke, nitrogen oxides, particulate matters, sulfur oxides, carbon dioxide and carbon monoxide emissions. Many researchers try to solve these problems using newly alternative fuels. Water-in-diesel fuel nanoemulsions are considered one of these newly alternative fuels in use. Fuel emulsification with water has been considered an effective technique for reducing emissions and enhancing fuel combustion efficiency for diesel engines. In this work, water-in-diesel fuel nanoemulsions with mean droplet size (49.55-190.1 nm) were prepared by mixed nonionic surfactants. The interfacial tension, thermodynamic properties, nanoemulsions stability, physical and rheological properties were investigated. This work is useful to factories and companies that concerned with increasing their economy by reducing coasts of their transportation, increasing of engines efficiency and reducing emissions. ····· 1036119929
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray This book reports the preparation and characterization of new rod-coil amphiphiles functionalized with oligo- and polysaccharides through Huisgen 1,3-dipolar cycloaddition reactions between species functionalized by an azide group on one side and an terminal alkyne on the other catalyzed by copper. The amphiphiles were synthesized and characterized based on different hydrophobic parts conjugated with the polymer poly(ethylene oxide) PEO with a hydrophilic spacer arm and the oligo- and polyssaccharides 2-propargyl-2-acetamido- 2-deoxy- -D-glucopyranose (GlcNAc) and propargyl -D-galactopyranosyl-(1-4)- -D-glucopyranose (Lac). The amphiphiles synthesized were characterized in terms of their chemical structure and composition through nuclear magnetic resonance (NMR),mass spectroscopy (MALDI-TOF-MS and ESI-MS)and high resolution mass spectroscopy (HRMS). After the dissolution in water, the amphiphiles self-associate in highly regular micelles with an average diameter of 2RH~10nm. Dynamic light scattering (DLS), transmission electron microscopy (TEM) and small angle x-ray scattering (SAXS) were used in order to investigate the structure and dynamics of these saccharide amphiphiles. ····· 1036119835
····· lezzter Preis 71.10€ ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray The subject of this work involves the investigation of the polarization behaviour of aluminium as well as of three of aluminium base alloys in sodium hydroxide solutions over temperature range (298 313 K). The major subjects of the work and the main results obtained may be presented as follows : 1- Polarization behaviour studies of pure Al and its three alloys Al-Cu-Mg (2024), Al-Mg (5083), and Al-Zn-Mg (7075). The research was performed in three concentration of NaOH solution at pH values of 13, 11, and 9. The polarization behaviour of pure Al and its alloys have been examined using a potentiostat (Corroscript) which was obtained from Tacussel (France) at a scan rate of 0.3 Volt per minute. The main results obtained were expressed in terms of the corrosion potentials (Ecorr) and corrosion current densities (icorr). Cathodic and anodic Tafel slopes and transfer coefficients were calculated and the results were interpreted according to the rate determining step from charge transfer process to either chemical desorption or to electrochemical desorption.2- Study the effect of chloride ions, the corrosion potentials and corrosion current densities also were changed considera ····· 1036119408
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Silica aerogels are the lightest of all solid substances having a very porous internal structure, which leads to a number of interesting properties. They possess very low thermal conductivity as well as a huge internal surface area. Now a day silica aerogels are used as thermal insulator in temperature-resistance windows, refrigerators, ovens etc. They are synthesized by the supercritical or ambient pressure drying of the liquid silica gels. But , the use of expensive alkoxide precursors and supercritical drying method for the synthesis of silica aerogels restricts their large scale production. So, for the commercialization purpose sol-gel processing of sodium silicate based aerogels via ambient pressure drying is described in this context and their physico-chemical properties are studied. ····· 1036119268
für 61.20€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray the photoreduction of methylene blue was carried out in presence of various reducing agents at different acidities. Acidities of the solutions were determined by Hammett acidity function (Ho). The quantum yield of the reaction varies directly with the increase in the concentration of the reductants and temperatures. The results and experimental findings obtained were also interpreted in terms of comparative reaction mechanism associated with reported work, in terms of structure and concentration of reducing agents. From the present investigation it has become more certain that the quantum yield is essentially controlled by two equilibria. i. The triplet state of methylene blue with the proton and the protonated triplet state of methylene blue. ii. The protonated triplet state of methylene blue with reductants, and associated complex of methylene blue. Since the quantum yield is directly proportional to the rate constant and varies with temperature, Arrhenius and Eyring relationships were used to calculate activation parameters such as energy of activation (Ea), free energy change of activation , enthalpy change and entropy change of activation. ····· 1036119065
für 61.20€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Charge carrier transfer reactions have been widely acclaimed to be very important as they play a pivotal role in photocatalytic processes. The fundamental study of the dynamics of the charge transfer processes is important in the design of new photocatalysts as well as for the industrialization of the photocatlytic processes. During the past decades, extensive investigations have been performed concerning the study of the kinetics and of the mechanistic details of the interfacial electron transfer processes at the semiconductor/water interface using the laser photolysis and the pulse radiolysis technique. I invite the world-recognized scientists who are specialists in photocatalysis to contribute specific chapters to this monograph.This is to cover the major aspects in photocatalysis from fundamentals to applications. The main objective of the present book is to study the dynamics of the charge carrier transfer processes induced by light at TiO2 nanoparticle/liquid (metal ions, organic molecules, O2, ...) interfaces and to elucidate the mechanistic models for a better understanding of photocatalytic reactions. ····· 1036119062
für 74.61€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Carbon Nanotubes play a special role in the realm of carbon nanostructures. Many applications of carbon nanotubes have started coming to Adsorption of Carbon Nanotubes in recent years and this is a research direction of great promise. Therefore, a book with an Adsorption and Desorption in Carbon Nanotubes focus is especially timely. That the authors of the book have many years of experience in Adsorption in Carbon Nanotubes research and in commercial exploitation of carbon nanotubes makes this volume of even greater importance and value, as they share this expertise and experience with students, researchers, and others. ····· 1036118887
für 71.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Hydrides for solid-state hydrogen storage are one of the future solutions - pollutant free - for the storage and the transport of energy. Among the candidates, LiBH4 was selected considering its high gravimetric hydrogen capacity (up to 13.6 wt.% H2). Its decomposition can be facilitated within the presence of the hydride MgH2. Thus, the hydride system MgH2-xLiBH4 (0x3.5) reactivated by high energy ball-milling, was studied regarding its microstructural properties and stability of the phases. The desorption reaction of hydrogen, with or without additives, shows the appearance of additional phases accompanying the principal reaction. Heat capacity measurements of LiBH4 revealed the presence of an abnormal behaviour before the polymorphous transition attributed to the increase of crystal defects in agreement with the existence of a hypo-stoichiometric domaine observed at higher temperatures. Vapour pressure measurements of LiBH4 showed that H2 is the major component of decomposition with minor species such as B2H6 and BH3. The thermodynamic properties of LiBH4 were critically assessed, gathering the new data, in the aim of modelling of reactions occurring in hydride mixtures. ····· 1036118150
für 44.10€ kaufen ···· Rheinberg-Buch.de - Bücher, eBooks, DVD & Blu-ray Zinc electrodeposition has long been utilised as a sacrificial coating to protect steel from corrosion. However, the life span of such coatings is limited due to the aggressive nature of some environments, particularly those containing industrial pollutants. Consequently, considerable efforts are being made to improve their corrosion resistance. In order to improve the technological properties of these coating, zinc composite coating is considered as an alternate and effective method. Electrodeposition is a low-temperature process used to fabricate nanocomposite coatings in a single step without secondary treatment. Nanocomposites have attracted research interest due to their unique functional properties such as improved corrosion and wear resistance, lubricity semiconductor properties, magnetic properties and superconduction. This Book highlights the production of Zinc/ Zinc alloy- Nano particles composites by electrodeposition method. In this work all the coatings are characterized by different spectral and electrochemical methods. Corrosion behaviors of these composite coatings were studied by chemical and electrochemical methods. ····· 1036118108
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