Showing papers in "IEEE Electrical Insulation Magazine in 2003"

Dielectric spectroscopy in time and frequency domain for HV power equipment. I. Theoretical considerations

Abstract: Most dangerous breakdowns are caused by the aging effects of HV insulation systems used within HV components, and there is still a lack of appropriate tools to diagnose such systems non-destructively and reliably in the field. This review introduces the theoretical background of dielectric spectroscopy in the time and frequency domains and provides an overview about the specific measuring methods based on this background. The specific methods treated are used for diagnosing electric insulation materials used in power engineering. It indicates that some of these methods may not be sufficient to gain full information about the actual conditions of a test object and that either measurements of polarization and depolarization currents (PDC in the time domain or measurements of C-tan/spl delta/ values (or complex permittivity) in the frequency domain (FDS) should be preferred to obtain a "dielectric response function" which offers much more information to judge the actual state of an insulation material or system.

Applications of dielectric spectroscopy in time and frequency domain for HV power equipment

Abstract: Dielectric spectroscopy in the time or frequency domain offers new opportunities for an off-line, on-site insulation condition assessment of HV electric power equipment and its predictive maintenance.

A general review of polymeric insulation for use in HVDC cables

Abstract: The authors present a review article of the properties of XLPE and an examination of the origins of space charge and how it is measured. The space charge in the insulation and the conduction current can affect the electric stress distribution in the insulation. The effect of morphology on the electrical properties of polyethylene is discussed in detail.

Diagnosing transformer faults using frequency response analysis

Abstract: This technique measures the impedance of transformer windings over a wide frequency range and compares the results with reference data The author used a network analyzer to sweep the frequency range, make the measurements, and analyze the results

A new approach to the diagnosis of solid insulation systems based on PD signal inference

Abstract: The authors have developed digital instrumentation that can measure the amplitude, shape, phase, and number of pulses per cycle. Examples are given of results obtained from an induction motor, a hydrogenerator, a polymeric cable system with a defective joint, and a high-voltage current transformer.

New techniques for dissolved gas-in-oil analysis

Abstract: Dissolved gas analysis (DGA) is one of the major maintenance tools for monitoring faults in high-voltage electrical equipment in service. An increasing number of oil samples are analyzed for DGA in laboratories. This paper, a report of CIGRE Task Force 15-01-07, evaluates several newly developed techniques to extract gas from oils. Five new techniques were investigated, in addition to standard methods, by means of four round robin tests carried out in twenty-five laboratories.

The case for frequency domain PD testing in the context of distribution cable

Abstract: Frequency domain PD testing offers a rich set of PD characterization tools, the most basic of which are described in the article. PD detection sensitivity under field conditions is one to two orders of magnitude greater than for time domain testing as a result of (i) no need to trigger on the first PD pulse above the broadband noise, and (ii) the filtering effect of the cable between the PD detection site and the terminations. As a result of this greatly increased sensitivity and the rich set of characterization tools, frequency domain PD testing has been developed into a highly sensitive and reliable tool for characterizing the condition of distribution cable during normal operation, the sensitivity and accuracy of which have been confirmed through independent testing.

The application of matched filters to PD detection and localization

Abstract: In practice, partial discharge (PD) signals are corrupted mainly by narrowband noise caused by radio communications. Matched filters are very well suited for PD detection in the presence of such noise, since they exploit spectral regions with high SNR to maximize the SNR of a measured PD signal. In addition to its noise suppressing capabilities, a matched filter provides a means to estimate accurately PD pulse magnitude and arrival time. Consequently, PD detection can benefit greatly from the application of matched filters. However, good knowledge of the signal waveform is required. In many cases, such information can be obtained by measurement or modeling of the PD pulse propagation.

Electrical stress enhancement of contaminants in XLPE insulation used for power cables

Abstract: The use of XLPE as the insulation for power cables has grown steadily since it first introduction more than 30 years ago. Today XLPE is rapidly becoming the preferred insulation system for even the highest transmission voltages. This preference is due to the high reliability, low dielectric losses, and low environmental impact that can be achieved with XLPE. The positive effects of high quality insulation materials on improved cable performance have been well known since the start of cable making. The purpose of this paper is to investigate the technical background for the cleanliness levels and to quantify the level of performance required from clean materials. The advantages of clean insulation materials are seen at all voltages. However, this work focuses on the technical basis for the benefits for HV and EHV cables, which typically are designed with a water impervious layer to ensure that the cable remains dry throughout its entire lifetime. The presence of metallic contaminants in MV cable is known to enhance the growth of trees by raising the electric stress level locally. The singular impact of cleanliness on the performance of MV cables is somewhat more complicated as it is influenced both by the cleanliness of the insulation and the ability of the insulation material to resist the growth of water trees.

Development of sequential build-up multilayer printed wiring boards in Japan

Abstract: Printed Wiring Boards (PWB) made by Sequential Build-Up (SBU) processes have found a wide application in semiconductor packaging substrates and system in package substrates, besides usage as a conventional printed wiring board. Its capability for high density circuits can contain multi-functional electronic circuits within a small surface area and can achieve light weight and low-profile products with improved electric characteristics. A number of processes and materials were developed and are used for each application in each electronic product. The advancement of printed wiring boards is expected to continue, driven by the requirements from electronic products. Technical development activities are needed to satisfy these requirements. Activities are still high in the development of embedded passive technology, which will equip printed wiring boards with the functions of passive components resistance (R), capacitance (C) and inductance (L) - as well as the conventional interconnection functions of conductors between components. This technology will dramatically change the structure of printed wiring boards and complicate the fabrication processes. Material development will be a key issue in the case of embedded resistors and capacitors.

Handbook of monochromatic XPS spectra - The elements and native oxides [Book Review]

Abstract: chanical drawing pencil, or a great set of golf clubs. Products must not only satisfactorily perform their intended function, but great products also satisfy the customers desire for aesthetics, product “feel,” and longlasting quality. Materials and material processes play an important role in creating color, texture, and feel in a product. Especially today, these factors can differentiate a product from a competitor’s, especially in mature products where the performance and costs are similar. This book presents the role of materials and processes on product design. Its focus is information on materials, especially polymers, needed by product designers. It is broken down into two parts. The first part presents design and materials selection methodology (i.e., ways to help product designers improve their creativity). This is achieved through topics ranging from influences in product design, product history, how materials are shaped and joined, case studies, and new materials. The second half of the book contains a practical reference guide on a variety of polymers, metals, and ceramics. A one-page summary, for each material covered, lists important technical parameters, costs, aesthetics, and other features relative to other materials. It provides a great way to quickly narrow down material choices when designing products. There are also excellent summaries on shaping processes (molding, casting, bulk forming, lay-up methods, and rapid prototyping) and surface profiles (printing techniques, plating methods, polishing, and coating processes). The book would benefit both students and working product designers. Students will find a good working knowledge to enable them to learn what is needed in industry, and those product designers working in industry, would find this a concise reference source for identifying materials and processes. Power System Operations and Electricity Markets F.I. Denny and D.E. Dismukes CRC Press LLC 2000 N.W. Corporate Blvd. Boca Raton, FL 33431 Phone +1 800 272 7737 Fax +1 800 374 3401 http://www.crcpress.com ISBN 0-8493-0813-5 134 pp. $ 99.95 (Hardcover), 2002 With the new policy of deregulating the electric power industry in the U.S., with the intention of promoting open access and competition, power companies now have to compete for markets that were previously guaranteed. Competition has taken the power industry from a technology driven business into a market driven business. This book focuses on this new business environment in the power industry. It is intended for new engineers in the power industry, professionals in management, regulatory, and operational positions, industrial power engineers, and utility company employees. In order to meet the challenges of a new competitive environment, engineers and other professionals in the industry must acquire new knowledge and become aware of other disciplines (power marketers). The book covers new technologies and methods for power systems operations. The authors do this by providing an overview of essential topics in energy policy, market economics, and power systems engineering. Some of the specific topics included are a good description of power marketers, distributed generation, independent power producers, reliability and control concepts. The authors have written a concise overview of the business challenges that now must be adopted by utilities and other players in the power generation business in order to remain competitive. Anyone wanting to know why the industry has changed, what the new business environment is now like, and what some of the technical challenges are to meet the new changes will find this book very interesting and useful.

Submerged cryogenic motor materials development

Abstract: A unique application for three-phase random and form-wound squirrel-cage motors and generators and their insulation systems is their operation while submerged in liquefied gases at cryogenic temperatures. Motors utilized for this service initially appeared in the late 1950s using standard air-motor designs and insulation systems. More specialized systems and designs were developed throughout the 1970s and 1980s and, as more extensive testing was conducted on motors in these applications, a better understanding of the properties of materials operating in dielectric fluids at cryogenic temperatures was gained. It was found that many of the problems associated with air motors, such as partial discharge, corona, thermal life, and oxidation, were absent on submerged motors. This has enabled engineers to better tailor each motor to its specific application. Over the years, end users have been steadily increasing the demands on these motors, and their sizes have grown ever larger. Today, submerged electric motors are used at loads as high as 2,500 kW, 7 kV, and in a wide variety of liquids, many much warmer than the cryogenic temperatures of earlier designs.

The transport of copper through oil-impregnated paper insulation in electrical current transformers and bushings

Abstract: In an investigation of OIP (oil impregnated paper) insulation removed from current transformers and bushings that have failed or have been taken out of service, the authors observed dark stains near the paper adjacent to copper braids that is used for capacitive grading. They investigate their cause and how they might affect the performance of the insulation. Analytical tests show that the stains were copper oxides, the type of oxide depending on the availability of oxygen.

Interfacial electrokinetics and electrophoresis [Book Review]

Abstract: Glow Discharge Optical Emission Spectrometry R. Payling, D. Jones, and A. Bengtson John Wiley & Sons Inc. 605 Third Ave New York, NY 10158 Phone +1 800 225 5945 Fax +1 212 850 6008 http://www.wiley.com ISBN 0-471-96683-5 846 pp. $389.00 (Hardback), 1997 In glow discharge optical emission spectroscopy (GD-OES), sputtering and emission are combined to analyze the surface of bulk solids and to depth profile surfaces, coatings, and interfaces. Being a vacuum technique, GD-OES is used to analyze practically any solid material. Today, this method is used to routinely study industrial and research materials to determine the composition of polymers, metallic alloys, layered semiconductors, and glasses. This book is a valuable reference work for anyone using or learning about this technique. It contains the widest possible coverage of both theory and application on GD-OES, from various experts in the field. Even with so many contributing authors, the editors managed to maintain a consistent style and content throughout the text, making the book very readable. The book begins with a brief history of GD-OES, and then leads into a very thorough review of GD-OES fundamentals, which covers GD-OES equipment design, operation, and the theory of processes occurring inside the glow discharge source. There are extensive details on setting up the equipment to perform GD-OES, using DC and RF sources, sputtering, depth profiling, optical emission characteristics, and calibration methods. Geared more towards the practical side, this book also contains a full range of practical analysis techniques, some of which include depth profiling of filled polymer coatings, metallic coatings, and metal interfaces. There is an interesting chapter comparing the strengths and weaknesses of GD-OES to various other surface analysis techniques (XPS, AES, and SIMS) and a comparison of GD-OES to spark discharge and mass spectroscopy. For those currently using the technique, there is an extensive bibliography and appendices listing spectral lines used in GD-OES for the elements. This book is intended for a wide audience ranging from engineers, scientists, and students in the field of optical emission spectroscopy. For those new to the subject, it will show how the technique can be used to analyze materials and, for those experts in the field, it will describe the latest advances in all areas of GDS-OES.

High field measurements with a guarded needle

Abstract: The electrical degradation of solid dielectrics often originates in the vicinity of defects (impurities, protrusions, or inclusions). The degradation involves a high field region of localized high carrier mobility that leads to the formation of a space charge limited field region in which charge cycles during application of an AC field. This cyclic carrier motion results in hot electrons and ultra-violet (UV) photons produced by carrier recombination, both of which can degrade the dielectric. Carrier mobility-related prebreakdown phenomena can only be studied within microscopic dimensions, as the power dissipation would cause thermal runaway for a macroscopic geometry. The guarded needle apparatus is designed for such measurement, using a sharp metal needle to create local high electrical field, which induces carrier mobility.

Application of Maxwell solvers to PD Propagation. III. PD propagation in GIS

Abstract: A transient electromagnetic field analysis by the method of moments (MoM) has been used to simulate the propagation of high-frequency PD pulses in electric power equipment. The analysis of transient electromagnetic fields described here enables the propagation of high-frequency signals in electric power equipment to be displayed. The motivation for this work is the expectation that such computational methods will provide an improved basis for the application of PD-based diagnostics to power apparatus.

Conductive adhesives for electronics packaging [Book Review]

Abstract: Property Tailoring of Thermoplastics—Based Blends and Composites I. Chodak and I. Lacik, Eds. Wiley-VCH PO Box 101161 D-69451 Weinheim, Germany www.wiley-vch.de/home 357 pp. € 159 This book is based on papers presented at the 14th Bratislava International Conference on Modified Polymers, held in 2000. Several papers discuss the properties of polyolefins filled with carbon black or conductive poly(pyrrole). They describe the stability of electrical and mechanical properties of conductive composites, dielectric properties of lowfiller-content composites. Other papers compare composites of carbon black in a variety of polymers, and report effects of nickel filler in polymeric coatings. There are many other papers in the book relating to a wide variety of polymer blends, which may be of interest to our readers. —K.F. Schoch, Jr.

The performance appraisal question and answer book [Book Review]

Abstract: Partnering—The New Face of Leadership L. Segil, M. Goldsmith and J. Belasco, Eds. AMACOM 1601 Broadway New York, NY 10019 ISBN# 0-8144-0757-9 Phone +1 800 714 6395 Fax +1 518 891 2372 http://www.amacombooks.org 336 pp. $27.95 (Hardback), 2003 This book describes ways to develop business and leadership skills in the area of building partnerships. The authors describe changes in the ways people and businesses interact. According to the authors, business leaders are having to foster new skills that enable them to team or partner with their managers and employees, rather than the traditional top down management style. This is essential to survival in the global economy. The book goes on to describe how and why partnerships need to be formed. Six different types of partnerships are examined: three inside the organization (direct reports, co-workers, and managers) and three outside the organization (suppliers, customers, and competitors). An interesting section compared some of the differences between American leadership style to the European style. According to the writers, the North American business leaders’ importance and significance was measured by the size of their compensation package and how much publicity they received. According to the European writer, on the other hand, European business leaders would rather lay low and gain the respect of their peers by running a successful company. There are many other interesting and controversial contrasts in the book that make for some very interesting and enlightening reading. Other chapters focus on teambuilding, forming alliances, and on becoming a global leader. This self-improvement book would be of interest to those who work in teams and are interested in improving the team, and especially for those who manage teams.

Molecular Imprinting-From Fundamentals to Applications [Book Review]

Abstract: necessary to execute the attack. While this book is intended to provide IT managers with information to better secure their systems and not to promote hacking, there are just so many neat little tricks that the average computer user would never know about. For example, learning to reveal windows passwords, various web sites for obtaining information and the actual source code for recent viruses like “The I Love You” and Nimda worms. While this book is intended for IT professionals who are seasoned programmers, a good portion of the book could be useful to the average computer user just for knowing more about computer security.

Dielectric and thermoanalytical behavior and spectroscopic and kinetic evaluation of water in heat-resistant electrical insulating films

Abstract: Nowadays, along with requirements for developing heat-resistant electrical insulating materials, various kinds of high polymers with polar structures are used, which are characterized by high heat-stability, good electrical properties, hydrophilic nature, etc. While their heat-stability is beneficial to their uses, their hydrophilic nature is sometimes detrimental, since the existence of water in electrical insulation is apt to deteriorate their electrical properties and dimensional stability. How water interacts with the polymer molecules in electrical insulating materials is an important issue to be solved; how inadequately the water can be classified into its free and bound forms in the materials has always been an interesting question. Heat resistant electrical insulating materials to be studied were selected and specimens conditioned by exposing them to moisture or immersing in water. The materials chosen were the following high polymeric films: Aramid, polyamide, biaxially oriented polyethylene terephthalate (PET), and biaxially-oriented polyethylene naphthalate (PEN); and an aromatic polyamide (Aramid) paper.

Characterization of materials [Book Review]

Abstract: and the Environment, vol. 27, 2002 R.H. Socolow, D. Anderson, and J. Harte Annual Reviews 4139 El Camino Way P.O Box 10139 Palo Alto, CA 94303-0139 Woburn, MA 01801-2041 Phone +1 800 523 8635 Fax +1 650 424 0910 http://www.annualreviews.org ISBN 0-8243-2327-0 472 pp. $82.00 (Hardback), 2002 This Annual Review of Energy and the Environment covers major current issues dealing with energy and the environment. These issues generally cover topics like energy conservation, resources, technology, economics, policy, and international and regional issues. Since this volume covers topics that mainly deal with appliance efficiency, fossil fuel air pollution, renewable energy sources, and air pollution, the majority of this volume would be of interest to those who work in these areas. Ideally, engineers, policy makers, or management in fossil fuel plants, appliance manufacturers, or policy makers in industries affected by air pollution standards. Examples of reviews include the appliance and equipment efficiency standards that cover the history of the standards and current status. The impact these standards have had over the past 30 years on energy efficiency on various appliances and the latest issues, future direction, and the impact these standards have had on manufacturers are also detailed. Another section covers renewable energy markets in developing countries. This author reviews some of the experiences of renewable energy use in various countries. Some of the renewables discussed are hydro, solar, biogas, and wind generation. Estimates for business growth in these technologies are also given. Industrial Design of Plastics Products M.J. Gordon, Jr. John Wiley & Sons 605 3rd Ave 4th Floor New York, NY 10158 Phone +1 212 850 6011 Fax: +1 800 597 3299 http://www.wiley.com ISBN 0-471-23151-7 565 pp. $110.00 (Hardcover), 2003 Plastics are being used in virtually all kinds of products today; even replacing parts traditionally made from metals. Successful design of plastic components still relies on the same engineering formulas and procedures used for the design of metal parts. However, the use of plastics requires knowledge in different areas from material choice, how the material characteristics perform in the intended environment, processing, creep, forces, and many other considerations. This book covers the information that a plastics designer needs to successfully develop a plastic part. Depending on the complexity of the part, plastic part design can be very involved. A team effort is generally the norm today. So, the book begins with design team selection and goes through a number of checklists to insure the correct development path is taken. The Appendix is loaded with various checklists to insure that no part of the development process is overlooked. These are suitable for copying and actual use. These lists cover information on development guidelines, vendor selection, materials, customer requirements, tooling, specifications, manufacturing, quality, and part cost. The next third of the book continues with specific and practical information on manufacturing methods, part design analysis, materials property considerations, environmental effects, thermal and electrical property effects. The electrical effects section, mainly describes common ULand IEEE-type test arrangements used in industry for arc tracking, dielectric strength, surface resistivity, permittivity, and flammability. There is, however, little actual data on materials’ electrical behavior, but there is a good description of the flammability tests. The remainder of the book covers analysis of materials’ properties (e.g. density, toughness, shrinkage, homogeneity, etc.), product design considerations (stress-strain analysis), structural product analysis, design for product performance (computer models and FEA), and product and tooling guidelines (lots of good practical mold design tips). Be aware that this text covers only thermoset materials and injection molding processes. Thermoplastic part designers, mold designers for plastics, and anyone involved in the development of thermoplastic parts will find this book to be an excellent resource of practical information covering all the critical areas of thermoplastic part development.

Power Transformers-Principles and Applications [Book Review]

Abstract: derstanding of many of the problems facing management, especially in larger corporations. He covers many of the typical issues that are present in virtually every corporation and presents the issues in a way that many managers may agree with but do not practice. For example, almost every company has some type of quality program. They come under various names like quality assurance, ISO, total quality, JIT, etc. As the author points out, while some of these methodologies are good for some companies, management often blindly signs up for numerous initiatives, even though it may not be the best for the company. The author stresses that a manager’s objective should be to help the company’s bottom line and focus on the problems at hand, rather than trying the latest fad in the business world. With all the new trends, acronyms, and buzzwords that get used every year by management with the thought of improving their business, this book examines the good and the bad in those practices, including leadership, accounting methods, performance appraisals, project management, personnel issues, quality, and a lot more. It provides good insight into issues managers face. It is a very quick, entertaining read and is very informative, and would be suited for managers in all industries and employees interested in learning more about where their company is headed.

History of the Electrical Insulation Conference

Abstract: This Electrical Insulation Conference (EIC) history gives a wide-ranging documentation of the EIC, from its inception in 1958 to the present. The EIC's inception was driven by advances in polymer technology. The EIC awards are outlined as is co-sponsorship of the conference.

Distributed generation-the power paradigm for the new millennium [Book Review]

Abstract: Warrendale, PA 15086 Phone +1 724 779 3003 http://www.mrs.org ISBN# 1-55899-661-3 284 pp. $78.00 members, $90.00 non-members (Hardback), 2002 This volume, from the MRS Spring 2002 meeting in San Francisco, CA, contains papers that cover some of the recent advances in polymeric LED’s, photovoltaics, organic materials for nonlinear optics, and transistors. Therefore, readers interested in these fields of organic opto-electronics will find many interesting and informative papers in these proceedings. With regard to light emitting polymers, there is an invited paper on the synthesis of novel light emitting polymers, one on the influence of barrier materials on device performance, and a few others on transport properties. Selected papers on organic transistors include organic materials selection, charge transport properties, and processing and device design. Two photovoltaic papers of interest cover the influence of microstructure in organic solar cells, and characteristics of polyfluorene based devices. A couple of papers of potential interest in the nonlinear organic materials section include two on conducting polymers. And there is one on inherently conducting polymeric thinfilms (structure and morphology differences in pyrrole and thiophene) and the other on blends of polystyrene/liquid crystalline polymer with carbon black (CB) (resistivity for various amounts of CB to polymer ratio at different shear rates for sensors applications).

Electrorheological fluids and magnetorheological suspensions [Book Review]

Abstract: Electrorheological Fluids and Magnetorheological Suspensions G. Bossis, Ed. World Scientific Publishing Co. P.O. Box 128 Farrer Road Singapore 912805 In the USA: 1060 Main Street, Suite 1B River Edge, NJ 07661 Phone +1 800 227 7562 Fax +1 888 977 2665 http://www.worldscientific.com ISBN 981-02-4937-3 904 pp. $168.00 (Hardback), 2002 This book is the proceedings from the 8th International Conference on Electrorheological (ER) Fluids and Magnetorheological (MR) Suspensions and their applications, held in France in July 2001. These proceedings consist of 130 papers giving the state-of-the-art in ER/MR research. ER/MR technology is an exciting and growing field. The novelty of ER/MR fluids is in the ability to control their material properties, such as viscosity or particle orientation in the fluid, via an external electric or magnetic field. By providing the appropriate external field, dynamic changes in the material properties result. Having materials with dynamic properties that are controllable has opened up a new area of research. Commercial applications are already being used in damping, vacuum sealing, and walking machines for the handicapped. Future applications may begin to appear in automobiles, aircraft, helicopters, and even earthquake-proof buildings and bridges. The proceedings are broken down into four chapters. The first, on applications, covers the bulk of the text. Applications range from high precision finishing, brakes, clutches, vibration damping, tribology, and shock absorbers. Many of the papers give material properties as well as the design ideas for the various applications. Some of the papers give good details into how the fluids used were made. The next section, on microstructures, show how particles, suspended in a fluid, change with the application of a field. There are detailed micrographs showing how particles form chain structures with the application of an external field. The third section on material properties shows the effects of various materials on the ER/MR characteristics. Some of these include the effects of rare earth compounds, nanosized iron particles, ferrite loaded polymer gels, effects of surfactants, and many other materials. The fourth section covers the physical mechanisms of ER/MR fluids. These include temperature dependence, particle size and shape effects, and heat transfer to surfaces, along with many theoretical models attempting to explain property behavior. This is an exceptionally documented proceedings, with many formulations, design ideas for applications, material properties, and characteristics that are clearly revealed. Any researcher involved with ER/MR fluids would find this book to be an excellent reference for design ideas and material properties of ER/MR fluids. Victory! Applying the Proven Principles of Military Strategy to Achieve Greater Success in Your Business and Personal Life B. Tracy AMACOM 1601 Broadway New York, NY 10019 Phone +1 800 714 6395 Fax +1 212 903 8083 http://www.amacombooks.org ISBN 0-8144-0750-1 310 pp. $24.95 (Hardback), 2002 Many great military leaders used similar principles and tactics to achieve success. The author has studied great military leaders and battles to learn the principles used to achieve success, and then condensed this into a set of principles. The main goal of this book is to save the reader an enormous amount of time in achieving your most important goals. He has identified twelve principles from which one can achieve success in business or personal life. The most important principle, identified in his studies, was to set clear, realistic objectives—and attain them. Each principle helps you to achieve your goals in the shortest amount of time. A condensed version of these twelve principles follows.