Ebooks de ciencias, página 22 de 709

Este libro se ha escrito para un curso introductorio en Cálculo de Probabilidades y Estadística, y como el título indica, para estudiantes de Ingeniería y Ciencias físicas. Los conocimientos matemáticos que debe tener el lector son los de un curso de Calculo, por lo que encaja bien en los planes de estudios de las Escuelas Tecnicas o Facultades Universitarias.

The broaching process remains an essential machining process when manufacturing fir tree slots in turbine disks for aircraft engines. The cost- and time-intensive experiment-based approach restricts the application of alternative cutting tool materials when broaching nickel-based alloys. Given the accuracy and computation time, the developed model-based multiscale approach presents great advantages in prediction of the broaching process and thus can accelerate the development process.

Este libro constituye una importante revisión de la edición anterior, si bien el enfoque general no se ha alterado y el nivel continúa siendo el mismo, quizá un poco incrementado al ampliar el campo. El texto se considera util para alumnos avanzados de Fisica e Ingenieria que esten familiarizados con el Calculo matematico.

Los suelos y su fertilidad está concebido como texto de curso introductorio de suelo, destinado a alumnos de ciencias agrícolas y ambientales. La presente edición ha sido totalmente revisada con la intencion de proporcionar un libro puesto al dia que conservara las cualidades probadas por la experiencia de las anteriores ediciones. Muchos de los principios y datos conseguidos en la segunda edicion son tan validos hoy como entonces, por lo que se ha conservado, añadiendo nuevo material. El conjunto ha sido objeto de nueva redaccion para presentar la materia de manera ordenada.

Aus okonomischen, okologischen und legislativen Grunden ist es notwendig Schmierstoffe zu substituieren. Insbesondere in der Kaltmassivumformung ist dies aufgrund von hohen Belastungen schwer umsetzbar. Der Ansatz dieser Dissertation ist es mithilfe einer vom Institut fur Oberflachentechnik entwickelten Werkzeugbeschichtung und einer Texturierung der Halbzeuge eine Trockenumformung zu ermoglichen. Die Ergebnisse haben eine Machbarkeit gezeigt, jedoch ist adhasiver Verschlei ein Problem.

Poly--glutamic acid (-PGA) is a biopolymer with various industrial applications. Despite its diverse applications, -PGA of defined molecular structure is costly. Sustainable synthesis of designer--PGA was achieved with a B. subtilis 168 derivative as host. In-depth investigations of the metabolism provided new targets for enhanced -PGA synthesis. The developed strains and cultivation conditions demonstrate the huge potential of microbial -PGA for the use in industrial applications.

Hydraulic Excavators are subjected to tip-over situations with potential hazardous outcome. The given work analyses the state of the art of tip-over protection methods, including the current mandatory overload protection system. Using methods derived from the area of robotics, an algorithm for use as an assistance system was developed to predict and actively prevent dangerous tip-over situations. The developed method was evaluated in multi-body simulation models and in physical field tests.

The present thesis provides a model to monetarily aggregate procurement risks to support decision makers. A material flow oriented view forms the fundament of the model. The model is designed to aggregate delay, quality and cost related procurement risks considering their uncertainty. Procurement risks are aggregated to form a monetary risk distribution. Decision-makers can select procurement strategies that are adequate for their risk situation, depending on their affinity for risk to mitigate procurement risks.

Systematic measurement errors in piezoelectric cutting force measurements are researched within this thesis. The errors originate from the seismic mass, which is mounted upon the transducer. On the one hand, the seismic mass reduces the bandwidth of the measurement system. On the other hand, the seismic mass leads to superimposed inertial forces, when the seismic mass is subjected to motion during cutting force measurement. Both effects are modelled and correction methods were researched, which are capable to correct these systematic measurement errors in hard real-time.

Given the fact of the increasing meaning of individual and functional micro- or nanostructures, it is of high interest to open up two-photon polymerization (TPP) as a structuring technology for production. TPP offers real 3D capability while providing a high precision, so arbitrary geometries with optical, photonic or biological func-tionalities can be realized. Thus, the aim is to use TPP as a mastering technology for metal substrates that serve as tools for injection moulding.

In job shop production the change towards synchronized job shop production, which is based on the concept of so-called taktlines, has been shown to enhance efficiency. In this dissertation an algorithm for the taktline layout is developed, following a multi-objective approach. The algorithm consists of two sequential discrete optimizations problems, namely a modified Substring Cover Problem and a partitioning Cluster Analysis, including a Multiple Sequence Alignment. For an overall validation, real-world data from tool manufacturers are subject to the proposed algorithm.

In the design of turbomachinery components, a significant effort is carried out regarding the optimization of efficiency. The increase in thermal efficiency particularly involves the introduction of high-performance alloys. Such alloys are for example titanium alloys. Sink electrical discharge machining (sink EDM) is a crucial manufacturing process for components due to its independence of machined material strengths; however, new materials require process design. Hence, research to understand and optimize the machining of titanium alloys is of great benefit to the industry in general.A positive tool polarity is generally adopted in sink EDM to maximize material removal relative to tool wear. Sink EDM of / titanium alloys as Ti6Al4V is however atypical in that these materials necessitate a negative tool polarity. Adding to the intrigue are gamma titanium aluminides (-TiAl), which machine better under the conventional positive polarity. Established explanatory models of sink EDM fail in resolving the removal behavior a need for fundamental research is given. This thesis focuses on clarifying the phenomena behind this interesting behavior by investigating removal mechanisms over a range of relevant process conditions. The polarity-effect is demonstrated to arise from the polarity-dependent nature and extent of titanium carbide (TiC) formation on the workpiece surface, which significantly affects material removal mechanisms. An explanatory model, deduced from different experimental and numerical approaches, clarifies the influence of polarity to the formation mechanism of a TiC layer. With regard to monitoring of adverse layer formations, the measurement of acoustic emission (AE) is proven an appropriate concept. A correlation of the AE signal to process forces is even established, which may be crucial to determine the deflection of thin electrodes in EDM. Finally, the knowledge acquired is applied and enhanced in comprehensive process design, that also involves the machining of additively manufactured -TiAl. The study reveals the beneficial behavior of the fine microstructure relative to the resulting surface integrity. As a result, this thesis delivers a model-based concept for process design with respect to the adequate choice of tool polarity during machining of titanium alloys.

A temperature and strain rates dependent fracture model is developed based on Weibull statistics to quantitatively describe the brittle-ductile transition of glass fracture in precision glass molding process. Under the assistance of FEM simulation, this fracture model can be used to calculate the fracture probability of glass during the precision glass molding process. Meanwhile, the most probable fracture timing, location of fracture initiation and fracture pattern can be also predicted.

Terpenoids include high value chemicals such as pharmaceuticals, chemical precursors and fine chemicals. Fruthermore, terpenoids are of interest as environmental-friendly replacement of fossil derivate chemicals. Here, the 2 C methyl D erythritol 4 phosphate (MEP) pathway was analyzed in Escherichia coli through metabolic control analysis for production of the model terpenoid isoprene. Several limiting steps were identified and their implication for an efficient pathway design is discussed.

Fueled by renewable feedstocks and powered from wind, sun, water and biomass the bioeconomy produces biobased chemicals and thus has the potential to create a sustainable chemical industry. In this dissertation, we investigated pseudomonads, a promising microbial platform organism for the bioeconomy. The complete genome of P. putida S12 was published and building blocks, namely styrene and anthranilate, which serve as precursors for bulk and high value products, were produced with pseudomonads.

This thesis presents the underlying mechanisms for the occurrence of surface anomalies in turning of difficult-to-cut materials with high-pressure coolant supply. Based on empirical and analytical investigations of each type of surface anomaly, the cause-and-effect relationships between the relevant process parameters and the surface quality were identified, translated into an explanation model and validated in a case study. Finally, an overview of different possibilities for anomaly-free machining with high-pressure coolant supply were discussed.

This work presents a new universal data management approach for eRobotics applications using distributed databases. The development and lifecycle of robotic systems features a high degree of complexity, made manageable by the eRobotics approach that combines electronic media, 3D simulation and robotics. The basis for any eRobotics application is a comprehensive 3D model of the system and its environment. Such highly complex models require an efficient data management provided in this thesis

Anatomy, particularly functional anatomy, is a vital and dynamic subject, an appreciation of which leads not only to superior husbandry and welfare, but also to a better understanding of the anatomical challenges associated with riding, training, overtraining, injury and rehabilitation. Using Alexa McKennas fabulous illustrations, this book shows the correlation of the skeleton, muscular system and locomotion, providing a clear insight into the functional and dysfunctional horse. It also addresses the largely misunderstood concept of perfect conformation and looks at the effect on function of the rider and tack, using cutting-edge diagnostic techniques such as thermal imaging and gait analysis. Again with the emphasis on the visual, readers will be able to appreciate how muscles function in differing athletic disciplines by analysing the heat generated in musculoskeletal structures after exercise. This will also highlight the importance of post-competition recovery. The book concludes with a range of useful techniques to improve the function of any horse, including stretches, taping, wrapping and other proprioceptive techniques to increase balance, flexibility, awareness and posture.

The manufacturing industry is undergoing major changes due to current trends like mass-customization and Industrie 4.0. However, todays CAx systems and approaches are not suitable to handle adaptive CAx process chains. To overcome this situation and to close the gaps between the existing CAx environment and the requirements for the manufacturing of the future, a modular approach based on extended function blocks is presented. The proposed approach is verified based on the use case of a worn-out BLIR segment by using repair features.

Irma Franzen-Heinrichsdorff was a 20th century landscape architect, who was not widely known in Germany. Her creative horticultural work included not least her impressive "landscape ideas" for private gardens, some of which are presented and paid tribute to here for the first time. In this book, Franzen-Heinrichsdorffs remarkable biography is traced using information from previously untapped sources. Franzen-Heinrichsdorff studied at the horticultural institute "Lehr- und Forschungsanstalt fur Gartenbau" in Berlin-Dahlem and became the first woman to gain the qualification of "Staatlich diplomierte Gartenbauinspektorin", i. e. horticultural inspector, in the subject of landscape gardening. She thereby attained the highest academic honour there was in this profession at the time. Influenced by expressionism and with an interest in music and dance, the accomplished illustrator and designer had a promising career as a landscape architect ahead of her. Rather than marrying the distinguished solo flutist Alfred Tibursky, the father of her two children, she tied the knot with landscape architect Gustav Heinrichsdorff, only to divorce him several years later. Family-related and professional difficulties forced Franzen-Heinrichsdorff to give up her career, and she went on to run a childrens home in the North Sea resort of Dangast for twenty years instead. Undeterred by intermittent harassment from National Socialists, she also cared for three foster children there over the years. It was not until later in life that she had the opportunity to work as a landscape architect once again in Colorado Springs in the United States of America; two of her former foster children and her son were instrumental in paving the way for her.