Friction welding can be achieved by several techniques; the simplest is the spin welding of two thermoplastics at relative speeds of up to 20 m s –1 under pressures of between 80 and 150 kPa. Welds of high quality may be produced in a few seconds, although residual stresses may be generated. Tubes and hollow sections can be welded satisfactorily and, since the process can be carried out in liquids, it is also a useful method of encapsulation of liquids. Relative movement of the components by vibration in linear oscillation may also be employed. This method of friction welding is widely used in the automotive manufacturing industry to produce large, complex joints. A development of this principle is ultrasonic welding, in which the parts to be joined are held together under pressure while mechanical vibrations perpendicular to the area of contact are applied by means of a piezo-electric transducer at frequencies in the range 20–40 kHz. As the energy output of these devices is limited, the size of possible weld is much smaller than that in normal vibration welding and tooling is expensive, but the method is well- suited to mass production and finds wide use in industry in the assembly of domestic products. No heat is required, and joint strengths approaching 100% of that of the parent materials are readily achieved.
materials such as metals, ceramics, plastics, composites, and nanomaterials. When it comes to traditional engineering undergraduate programs such as civil, mechanical, electrical, or chemical engineering, their specific materials science educational needs are quite different. While civil engineers deal mostly with steel, concrete, timber, and soils, their mechanical engineering counterparts are interested in different alloys and composite materials. With rapid economic development and the scarcity of natural resources, the use of synthetic materials (e.g., polymers, composites), industrial by products (e.g., slag, fly ash), recycled materials and their combinations with tradi tional materials (e.g., concrete and soils) has recently become more prevalent in civil engineering projects. Hence, there is a gro\ving need for civil engineers to learn more about these advanced materials in addition to traditional materials.
The development of civilization is insepara- bly concerned with the use of materials, hence the names of époques such as The Stone Age, The Bronze Age and the Iron Age. The advance- ment of science is related to the advancement in construction materials. Researchers keep devel- oping new materials. In 1980’s a group of ma- terials called intelligent materials appeared . Certain types of them had been known and used before, yet the discovery of their of specific fea- tures generated new interest in them. 1990’s and the beginning of the new millennium brought a lot of interest and turbulent advancement in their research. Different names of such materials can be encountered in literature: intelligent materials, smart materials, adaptive materials, or even mul- tifunctional materials.
compounds. A chalcogen is defined as any element from the group VI-A of the periodic table: oxygen (O), sulphur (S), selenium (Se), tellurium (Te) and polonium (Po). A chalcogenide is a chemical compound that has at least one element from this group as a negative ion. Oxygen has different chemical behaviour compared to other chalcogens, and is often treated separately. Metal chalcogenides have a high absorption coefficient and useful bandgaps for solar energy absorption. Thin films of chalcogenide materials can be deposited on a variety of substrates by vapour or liquid techniques such as evaporation, sputtering and chemical solution baths. Many metal chalcogenides have been used to make semiconductor-sensitised solid solar cells. The metal chalcogenide absorbers that have produced the higher semiconductor-sensitised solar cell efficiencies are cadmium chalcogenides (CdS, CdSe and CdTe), lead chalcogenides (PbS and PbSe) and antimony chalcogenides (Sb 2 S 3 and Sb 2 Se 3 ).
essary to consider the properties of all materials, making it. Clothes, basically, are a multilayer sys- tem consisting of: main material, lining, fusible interlining materials, insulation, thread, glue and accessories. The properties of each component of the package are important for the production of high quality products. Tests of one parameter are not suffi cient to determine the compliance of a package of materials to the specifi ed require- ments to the product, a set of properties that are included in its package are more signifi cant.
For ionic compounds, the situation is more complicated than for metals inasmuch as it is necessary to consider the diffusive motion of two types of ions that have opposite charges. Diffusion in these materials occurs by a vacancy mechanism (Figure 6.3a). And, as we noted in Section 5.3, in order to maintain charge neutrality in an ionic material, the following may be said about vacancies: (1) ion vacancies occur in pairs [as with Schottky defects (Figure 5.3)], (2) they form in nonstoichio- metric compounds (Figure 5.4), and (3) they are created by substitutional impurity ions having different charge states than the host ions (Example Problem 5.2). In any event, associated with the diffusive motion of a single ion is a transference of electrical charge. And in order to maintain localized charge neutrality in the vicinity of this moving ion, it is necessary that another species having an equal and opposite charge accompany the ion’s diffusive motion. Possible charged species include another vacancy, an impurity atom, or an electronic carrier [i.e., a free electron or hole (Section 12.6)]. It follows that the rate of diffusion of these electrically charged couples is limited by the diffusion rate of the slowest moving species.
Builders use ratios all the time; a simple tool may be referred to as a 5/8 or 3/16 wrench. Trusses must have the correct ratio of pitch to support the weight of roof and snow, cement must be the correct mixture to be sturdy, and doctors are always calculating ratios as they determine medications. Almost every job uses ratios one way or another; ratios are used in building & construction, model making, art and crafts, land surveying, die and tool making, food and cooking, chemical mixing, in automobile manufacturing and in aeroplane and parts making. Engineers use ratios to test structural and mechanical systems for capacity and safety issues. Millwrights use ratio to solve pulley rotation and gear problems. Operating engineers apply ratios to ensure the correct equipment is used to safely move heavy materials such as steel on worksites. It is therefore important that we have some working understanding of ratio and proportion.
During the Reformation, Martin Luther separated from the Catholic Church. He believed that the Bible was the ultimate source of truth, and that faith did not require works to be saved. John Calvin took Luther’s ideas even further. He believed in predestination. However, many people remained faithful to the Catholic Church and actively preached the Catholic message. These events led to a period of spiritual and political turmoil.
1. INTRODUCTION Engineering Statistics: What and Why? / Basic Terminology / Measurement: Its Importance and Difficulty / Mathematical Models, Reality and Data Analysis 2. DATA COLLECTION General Principles in the Collection of Engineering Data / Sampling in Enumerative Studies / Principles for Effective Experimentation / Some Common Experimental Plans / Preparing to Collect Engineering Data 3. ELEMENTARY DESCRIPTIVE STATISTICS Elementary Graphical and Tabular Treatment of Quantitative Data / Quantiles and Related Graphical Tools / Standard Numerical Summary Measures / Descriptive Statistics for Qualitative and Count Data (Optional) 4. DESCRIBING RELATIONSHIPS BETWEEN VARIABLES Fitting a Line by Least Squares / Fitting Curves and Surfaces by Least Squares / Fitted Effects for Factorial Data / Transformations and Choice of Measurement Scale (Optional) 5. THE PROBABILITY: THE MATHEMATICS OF RANDOMNESS (Discrete) Random Variables / Continuous Random Variables / Probability Plotting (Optional) / Joint Distributions and Independence / Functions of Several Random Variables 6. INTRODUCTION TO FORMAL STATISTICAL INFERENCE Large-Sample Confidence Intervals for a Mean / Large-Sample Significance Tests for a Mean / One-and Two-Sample Inference Means / One- and Two-Sample Inference for Variances / One- and Two-Sample Inference for Proportions / Prediction and Tolerance Intervals 7. INFERENCE OF UNSTRUCTURED MULTISAMPLE STUDIES The One-Way Normal Method / Simple Confidence Intervals in Multisample Studies / Two Simultaneous Confidence Interval Methods / The One-Way Analysis of Variance (ANOVA) / Shewhart Control Charts for Measurement Data / Shewhart Control Charts for Qualitative and Count Data 8. INFERENCE FOR FULL AND FRACTIONAL FACTORIAL STUDIES Basic Inference in Two-Way Factorials with Some Replication / p-Factor Studies with Two Levels for Each Factor / Standard Fractions of Two-Level Factorials; Part I: 1/2 Fractions / Standard Fractions of Two-Level Factorials; Part II: General 2"p-1" Studies 9. REGRESSION ANALYSIS-INFERENCE FOR CURVE- AND SURFACE-FITTING Inference Methods Related to Least Squares Fitting of a Line (Simple Linear Method) / Inference Methods for General Least Squares Curve- and Surface-Fitting (Multiple Linear Regression) / Application of Multiple Regression in Response Surface Problems and Factorial Analyses / APPENDIXES / A: MORE ON PROBABILITY AND MODEL FITTING / B: TABLES / ANSWERS TO END-OF-SECTION EXERCISES / INDEX
Joseph R. Dancy is an Adjunct Professor at SMU Dedman School of Law and SMU Cox School of Business. He graduated from Michigan Technological University with a B.S. in Metallurgical Engineering/Mineral Processing before earning an MBA at the University of Michigan and a JD from Oklahoma City University School of Law. He is president of LSGI Advisors Inc., a research and investment firm headquartered in Dallas. He is also a Texas Representative to the Interstate Oil & Gas Commission.
For the sake of history, Charles Nelson's 1867 clay torpedoes merit discussion. Viewed alongside other, later designs, this clay torpedo is a study in simplicity. The design works reliably, and is easy to make. Mr. Nelson, of New York City, received this patent on June 11, 1867. His is definitely not the oldest torpedo design -- that distinction probably belongs to the French pois fulminans, or mad peas. Nelson's torpedo is, however, an old and noteworthy design. It uses a molded clay ball for the structural mass of the torpedo combined with an explosive of the Armstrong's Mixture type. The patent (#65,764) claims that the design "involves the consumption of no paper or other valuable fibrous materials" which were in short supply following the Civil War. Nelson states that he prefers a mixture of fire-clay and pipe-clay about 50/50, although he states that "other material than clay may be used." 5
Vinogradava have been doing, especially when Bob Jahn, down at Princeton, is doing far more exciting original work [Professor Robert G. Jahn is Dean of the School of Engineering and Applied Science, Princeton University], and doing it in a scientifically credible setting. Frankly, I'm quite discouraged with most U.S. parapsychologists, as I believe they have a very limited view, and generally just hack the old data over and over again, hoping to discover something new - and, of course, they never will! It takes creativity and imagination to really see through these events and recognize where they are coming from. I find neither the Kulagina phenomena, nor Uri Geller's exceptional abilities [the Israeli psychic who specialized in bending keys and forks by "mind" power] of interest anymore. We know they can do it. Certainly it was important at that time, but that's been years ago, and there's no point in wasting our time in rehashing old events. I have moved to broader areas of concern.
Este artículo describe los problemas del tra- tamiento que rodea a la obra épica de JohnMartin Destruction of Pompeii and Hercula- neum (1821). La pintura sufrió un daño es- tructural tan grave después de la inundación del Támesis de 1928 que se dio por destruida. A pesar del gran daño causado por el agua, que afectó a todas las capas del cuadro y a la pérdida de aproximadamente una quinta parte del lienzo, estudios recientes revelaron que la obra está en condiciones de poder res- taurarse. Sin embargo, debido a la naturaleza extrema de los daños es necesario tener en cuenta ciertos aspectos éticos y técnicos con relación al tratamiento, en especial para rein- tegrar la gran sección faltante. Con el objetivo de obtener información para el proceso de tratamiento, se utilizó un estudio relacionado con la percepción del observador ante distin- tas simulaciones digitales para la reintegra- ción, así como la influencia de dichas simu- laciones en el comportamiento de la mirada del observador, y se hizo un seguimiento a través de métodos novedosos para seguir el movimiento del ojo.
This research was supported by the U.S. Department of Energy, Office of Science 共 OS 兲 , Office of Basic Energy Sci- ences 共 BES 兲 , and Materials Sciences Division. Ames Labo- ratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. W-7405-ENG-82.
The authors wish to thank Diane Ferland, Merrilee Loewen, Debrah Foster, Denise Foster, Linda Knox and XiangRu Lu for their help in completing this project. We are also indebted to the nursing staff and all other health pro- fessionals who contribute to the care of our patients and for actively sup- porting this research initiative. We also wish to acknowledge Fiona Daigle, My-Linh Tran, Di Wang and the data management team at the University of Ottawa, Clinical Epidemiology Unit. This work was made possible through the support of the Canadian Critical Care Trials Group, in particular Drs Tom Todd and Deborah Cook. We also would like to express a sincere thank you to the TRICC trial investigators: Ottawa General Hospital: Paul C Hébert; Toronto Hospital, General Division: John Marshall; Vancouver General Hospital: Martin Tweeddale; Victoria General Hospital, Halifax: Richard Hall; Royal Victoria Hospital, Montreal: Sheldon Magder; St Michael’s Hospital, Toronto: David Mazer; Wellesley Hospital: Thomas Stewart; Hamilton General Hospital: Thomas Hillers; Foothills Hospital, Calgary: Dean Sandham; St Paul’s Hospital, Vancouver: James A Russell; Hôpital Maisonneuve-Rosemont, Montreal: Yoanna Skrobik; Hôtel Dieu- Grace Hospital, Windsor: John Muscedere; Calgary General Hospital/Peter Lougheed Centre: Sidney Viner; Ottawa Civic Hospital: Giuseppe Pagliarello; Victoria Hospital, London: Claudio Martin; Health Science Centre, St John’s: Sharon Peters; Montreal General Hospital: David Fleiszer; Jewish General Hospital, Montreal: Alan Spanier; Toronto Hospital, Western Division: Patricia Houston; Saint Joseph’s Hospital, London: Ann Kirby; Royal University Hospital, Saskatoon: Jaime Pinilla; University Hospi- tal, Edmonton: Mary van Wijngaarden; Kingston General Hospital: Gordon Wood and Daren Heyland; Everett Chalmers Hospital, Fredericton: Navdeep Mehta; St John Regional Hospital: Michael Jacka.
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