IP (internet protocol) Telephony, enabled by softswitches, is going to usher in a new era in telecommunications. By putting voice and data over one IP network, operators can enjoy lower costs and create new, revenue-generating "multimedia" services. This valuable reference offers a comprehensive overview of the technology behind IP telephony and offers essential information to network engineers, designers and managers who need to understand the protocols and explore the issues involved in migrating the existing telephony infrastructure to an IP-based real time communication service. Drawing on extensive research and practical development experience in VoIP from its earliest stages, the authors give access to all the relevant standards and cutting-edge techniques in a single resource. IP Telephony: Deploying Voice-over-IP Protocols: Assumes a working knowledge of IP and networking and addresses the technical aspects of real-time communication over IP. Presents a high level overview of packet media transport technologies, covering all the major VoIP protocols - SIP, H323 and MGCP Details specific strategies to design services for public networks where endpoints cannot be trusted and can be behind firewalls. Explores the problems that may arise from incomplete protocol implementations, or architectures optimized for private networks which fail in a public environment. This amply illustrated, state-of-the art reference tool will be an invaluable resource for all those involved in the practical deployment of VoIP technology.
This comprehensive, truly one-stop reference discusses monomers, methods, stereochemistry, industrial applications and more. Chapters written by internationally acclaimed experts in their respective fields cover both basic principles and up-to-date information, ranging from the controlled ring-opening polymerization methods to polymer materials of industrial interest. All main classes of monomers including heterocyclics, cyclic olefins and alkynes, and cycloalkanes, are discussed separately as well as their specificities regarding the ring-opening polymerization techniques, the mechanisms, the degree of control, the properties of the related polymers and their applications. The two last chapters are devoted to the implementation of green chemistry in ring-opening polymerization processes.
Of much interest to chemists in academia and industry.
In 1999-2000, VoIP (Voice-over-IP) telephony was one of the most successful buzzwords of the telecom bubble era. However, in 2001-2003, VoIP faced a very tough reality check. Now, manufacturers and service providers are drawing on what they have learnt from past experience in order to prepare to participate in the next major challenge faced by the telecommunications industry. This book offers a comprehensive overview of the issues to solve in order to deploy global revenue-generating effective "multimedia" services. Drawing on extensive research and practical deployment experience in VoIP, the authors provide essential advice for those seeking to design and implement a post-bubble VoIP network. Beyond VoIP Protocols: Understanding Voice Technology and Networking Techniques for IP Telephony Introduces the basics of speech coding and voice quality Demonstrates how quality of service may be built into the network and deals with dimensioning aspects, e.g. multipoint communications and how to model call seizures. Explores the potential of multicast to turn an IP backbone into an optimized broadcast medium Includes amply illustrated, state-of-the-art practical advice for formulating a complete deployment strategy A companion volume to "IP Telephony: Deploying VoIP Protocols", this book takes the reader a stage deeper into how to prepare the network and exploit VoIP technology to its full potential.
Understanding the rheological properties of fresh concrete, the hydration phenomenon of cement responsible for structuration, the relationship between the characteristics of the porous solid obtained and its mechanical performances or resistance to the aggressive penetration requires a complex knowledge of the physicochemistry of reactive porous materials. The development of simple formulation rules therefore requires the assimilation of this knowledge and a good command of the properties of these materials.
The purpose of this book is to provide the mix designer with useful knowledge on granular materials and porous materials, which will enable the innovative design of concrete. Topics covered include the characterization of granular materials, the concepts of porosity and specific surface area, and the transport properties (diffusion and permeation) of concrete. Some of these topics are already covered in other general books dedicated to granular or porous materials. The objective here is to bring them together in one book by adapting them for use by concrete specialists.
Applications in the form of exercises are offered at the end of each chapter to enable readers to assimilate the theoretical knowledge and to apply such knowledge to concrete problems encountered in civil engineering. Contents 1. Description of Granular Materials, Definitions.
3. Specific Surface Area of Materials.
4. Voids in Granular Materials and the Arrangement of Grains.
5. Voids in Concrete.
6. The Fundamentals of Diffusion.
While very useful for studying syntheses of molecular diversity, multi-component reactions also offer rapid access to a variety of complex molecules that are relevant for biological applications. Multi-component Reactions in Molecular Diversity analyzes these reactions, whether they are realized by organometallic, ionic or even radical processes. It highlights popular methods based on monotype reactions (cascade, tandem, domino) and their efficiency and academic industrial domain are illustrated. This book also investigates the most efficient ways to prepare complex molecules. Multi-component reactions are in tune with the concepts of atom and steps economy, which are of prior importance in all the reported processes ? from the laboratory to the pilot scale. The essential criteria for green chemistry are also examined in the book in detail.
Biphasic Chemistry and The Solvent Case examines recent improvements in reaction conditions, in order to affirm the role of chemistry in the sustainable field. This book shows that those who work within the chemistry industry support limits for the use of toxic or flammable solvents, since it reduces the purifications to simple filtrations. Thanks to commercial scavengers, solid phase syntheses are now available to all. Fluorine biphasic catalysis enables extremely efficient catalyst recycling and has a high applicability potential at the industrial level. This book also reviews the many studies that have shown that water is a solvent of choice for most synthetic reactions. Particular traits can be obtained and the effects on thermodynamics make it possible to operate at lower temperatures, thereby achieving energy savings. Finally the great diversity of application of the reactions without solvents is illustrated.
Activation Methods examines recent improvements in the utilization of ultrasonic waves and pressurized gases to generate reactions. A straightforward method to use, sonochemistry allows chemical reactions to be carried out under ultrasound without the need for external heat, reagents or catalysts - leading to high yields and the production of a minimum amount of waste. This book presents an overview of the main applications of sonochemistry in green organic chemistry, with an emphasis on texts published within the last few years. High-pressure chemical reactions offer innovative solutions to problems relating to synthesis. They allow access to new products and a further understanding of reaction mechanisms. This book presents the characteristics of hyperbaric activation, which allow the integration of an arsenal of tools for green chemistry, such as the lowering of energy costs and of by-products, as well as the possibility of using substrates that are sterically congested and generally inert.