bluuebunny/crossref_metadata_2025 huggingface dataset:
A Survey of Macro-Microcrack Interaction Problems
Authors: Petrova Vera , Tamuzs Vitauts , Romalis Natalia
Published: April 2009

The results obtained on the problem of the interaction between a large crack and an array of microcracks or other microdefects are reviewed. The following problems are considered: interaction of main crack with microcracks in the two-dimensional case at tensile, shear or combined stress state; a closure of macro or microcracks as a result of their interaction, and the influence of this phenomenon on the stress intensity factor; the thermal cracking of an elastic solid caused by the macro-microcracks interaction and cracks closure; the interaction of a crack with an array of small pores or rigid inclusions; three-dimensional problems of the interaction of a penny-shaped crack with small penny-shaped microcracks. Discussed analytical results are based on the asymptotic analysis and the series solution to systems of singular integral equations describing the interaction of the macrocrack and microdefects. The series solutions were obtained with respect to the small parameter representing the ratio of micro- to macrocrack sizes. Throughout the review, the known solutions on the crack interaction are surveyed. The comparison with solutions to other relevant problems such as an interaction of semi-infinite crack with an array of finite cracks is given. The impact of a close crack location, and a comparison with relevant results of the continuum model approach are discussed. This review article includes 332 references.
Rewiew of Fracture and Fatigue in Ceramic Matrix Composites
Authors: Birman Victor , Byrd Larry W.
Published: April 2009

A review of recent developments and state-of-the-art in research and understanding of damage and fatigue of ceramic matrix composites is presented. Both laminated as well as woven configurations are considered. The work on the effects of high temperature on fracture and fatigue of ceramic matrix composites is emphasized, because these materials are usually designed to operate in hostile environments. Based on a detailed discussion of the mechanisms of failure, the problems that have to be addressed for a successful implementation of ceramic matrix composites in design and practical operational structures are outlined. This review article includes 317 references.
Aeroacoustics of the Vortex Ring
Authors: Kopiev V. F.
Published: April 2009

A review of recent achievements in the investigation of mechanisms of aerodynamic sound generation by turbulent vortices is presented. The results obtained, and their agreement, permit understanding of the mechanism of sound generation by a 3D vortex, as well as the formulation of a new concept of sound radiation by vortex structures. It appears that the noise of even one vortex, which seems at first to be a rather simple oscillating system, is in fact a highly complex random process, with quite definite peculiarities that can be recorded experimentally and predicted theoretically. This review article contains 60 references.
Smoke Propagation in Road Tunnels
Authors: Chen Falin
Published: April 2009

In tunnel fires, the most immediate threat to life is not the direct exposure to fire, but smoke inhalation. Efficient control of smoke propagation, therefore, is one of the most important issues in designing tunnel ventilation and a full understanding of the characteristics of smoke propagation in tunnels is a necessity in order to proceed with a successful design. In the present article, we review the progress of research on smoke propagation in tunnels, wherein the tests in full-scale tunnels, the nature of fire, the computational fluid dynamic-field model approach (CFD-FMA), and the Froude number preservation approach (FNPA) are discussed. The gravity current approach (GCA) is also developed to predict the smoke propagation behavior in tunnels and a CFD-FMA example is given from which the features of smoke propagation can be closely examined. The analytical results from FNPA indicate that, in the upstream of fire, the critical ventilation velocity is generally proportional to the one-third power of the heat release rate (HRR); some modifications to this power law are necessary for special cases. In the downstream of fire, the GCA results show that smoke propagates along the tunnel with a constant speed, which is essentially linearly proportional to the ventilation velocity. The numerical results from CFD-FMA determine a safety domain in terms of the ventilation velocity and the HRR of fire. In view of rapidly increasing computational power, the CFD-FMA is becoming a major approach in studying smoke propagation in tunnels, while the GCA and FNPA are useful in engineering design. This review article includes 60 references.
Optimal Protection From Impact and Shock: Theory and Methods
Authors: Balandin D. V. , Bolotnik N. N. , Pilkey W. D.
Published: April 2009

This review article gives a historical perspective of the achievements in the theory and methods of optimization of isolation systems and outlines the most important results, including some practical applications. The effectiveness of shock isolation is reviewed and the fact that in some cases the utilization of isolators does not lead to a reduction in the force transmitted to the body to be protected is discussed. Mathematical formulations of basic problems of optimization of shock isolation systems are surveyed, including those for the case where the external disturbance is not precisely prescribed. Particular attention is given to the limiting performance analysis aimed at the establishment of an absolute optimum of the response of the system, irrespective of its design and engineering implementation. A significant portion of this paper is devoted to the basic achievements in the theory of shock isolation of systems with one degree of freedom. Analytical solutions for such systems are reviewed in detail. Various computational techniques are outlined and compared. Promising potential directions of further developments are discussed. An extensive bibliography of relevant publications is provided. Included in this review are numerous publications from the former Soviet Union which heretofore have not received much exposure elsewhere. This review article contains 234 references.
Variation Analysis of Non-Rigid Assembly Using FEM and Fractals
Authors: Liao Xiaoyun , Wang G. Gary
Published: April 2009

Many studies on the assembly of non-rigid parts suggest that the part variation affects the assembly dimensional quality. However, little is known about how the detailed microstructure of part variation influences the assembly dimensional quality. In this paper, a new method based on the finite element method (FEM) and fractal geometry is proposed to explore the influence of the part variation microstructure on the assembly dimensional variation. In the new method, a special fractal function, the Weierstrass-Mandelbrot (W-M) function, is used to extract and represent the characteristics of the part variation microstructure. FEM is applied to analyze the deformation of non-rigid parts by integrating the part variation microstructure. The contribution of the detailed part variation to the final assembly deformation is obtained by the influence coefficients method. The proposed method is implemented by using commercial software tools, ANSYS and Matlab. The proposed method is illustrated through a case study on an assembly of two flat sheet metal parts. This new approach should benefit high precision assemblies.
Feature Recognition for Injection-Molded and Die-Cast Parts
Authors: Bidkar Rahul A. , McAdams Daniel A.
Published: April 2009

In this article, a framework to perform the computer-aided Design for Manufacturability analysis of injection-molded and die-cast parts is presented. The framework includes an implemented algorithm to solve key outstanding challenges in feature recognition for manufacturability analysis. The proposed feature recognition algorithms operate on a 3D binary array obtained from the solid model of the part. Solutions to the feature recognition problems of finding the best direction of mold closure, finding the mold parting line of the part and determining planarity of the parting surface is presented in this article. The feature recognition algorithms presented here are validated through application to several test parts. The algorithms proposed here recognize the direction of mold closure, the primary mold parting surface, undercuts, holes, and bosses present on the part. In addition, an estimated part mold cost is calculated by the algorithm.
Structured Approach to Dimensioning and Tolerancing: A Comprehensive Solution Strategy
Authors: Islam M. N.
Published: April 2009

This paper is the second of two in which a methodology is presented that provides a structured way of solving Dimensioning and Tolerancing (D&T) problems on new product design. In the previous paper, a methodology was developed for representing the D&T problems of a product in a matrix form known as a Dimensional Requirements/Dimensions (DR/D) matrix. In this paper a comprehensive strategy is presented for determining the values of dimensions and tolerances by satisfying all the relationships represented in DR/D matrix. The comprehensive strategy presented here includes: strategy for separating D&T problems into groups, for determining an optimum solution order for coupled functional equations and tolerance allocation strategies for solving different types of D&T problems. A number of commonly used cost minimization strategies such as the use of standard parts, preferred sizes, preferred fits, and preferred tolerances have also been incorporated into the proposed methodology. The methodology is interactive and suitable for use in a Concurrent Engineering environment.
Modeling of Supply Chain Decision Logic Using PID Controllers
Authors: See Tung-King , Kasprzak Edward M. , Singh Tarunraj , Lewis Kemper E.
Published: April 2009

Most manufacturing takes place in the context of a supply chain. Each station in the supply chain must not only manufacture a product but also decide how much to produce. This decision is influenced by the supply of materials/components from the next station down in the supply chain and the demand from the next station up. With the advent of increased customization, inventory management is increasingly becoming a critical issue in the manufacturing process. In this paper we model the decision logic at each stage of a supply chain system through the use of system identification and PID controllers. The goal is to investigate and manage the costs of manufacturing a product in the context of a supply chain. It is assumed that the supply chain has well-understood interactions between individual positions, allowing for a focus on the ordering decision logic. A review of ordering strategies is presented, and a discussion of the difficulties in determining PID gains for human decision makers is included. The results show a range of correlation between the PID simulation and measured supply chain inventories. This stems from a number of factors, which are discussed. Additionally, ordering strategies to optimize the supply chain are investigated.
Assembly Analysis of a Multi-Hinge Jamb-Slab System
Authors: Zhang Xianmin , Erdman Arthur G.
Published: April 2009

Assembly analysis of a multiple co-linear hinges jamb-slab system is studied in this paper. An analysis model is developed, in which both of the positioning errors of the pins on the jamb and the positioning errors of the cylinders on the slab are considered. The successful assembly condition is presented when the pins and cylinders are all in possible orientations. Simulations are carried out based on the models and the Monte Carlo method which can predict the successful assembly probability effectively. The work presented here is important both for research and practice in the door and window industries.
Design Process Error-Proofing: Engineering Peer Review Lessons From NASA
Authors: Chao Lawrence P. , Tumer Irem , Ishii Kosuke
Published: April 2009

This report describes the state of design reviews observed at NASA and research into improving review practices. There are many types of reviews at NASA. Formal, programmatic project reviews such as the Preliminary Design Review and Critical Design Review are a required part of every project and mission development. However, the informal and technical engineering peer reviews that support teams’ work on such projects are informal, ad hoc, and inconsistent across the organization. The goal of this work is to identify best practices and lessons learned from NASA’s review experience, benchmark against industry techniques, and develop methodologies to improve the process. Thus far, the research has determined that the organization, composition, scope, and execution, including the use of information technology and structured design methodologies, of reviews all impact the technical, engineering peer reviews to help NASA work towards error-proofing the design process.
Interactive Freeform Clay Modeling Supported by 3D Scanning and Robot Machining
Authors: Song Y. , Vergeest J. S. M. , Wiegers T.
Published: April 2009

Effective and efficient prototyping is always a challenging topic in design and prototyping. For this purpose, an interactive prototyping center is developed in this paper. The proposed technique is based on a synthesis of clay modeling, 3-Dimensional (3-D) scanning, robot machining and advanced geometric tools. Using 3-D scanning and reverse engineering techniques, a physical clay model is digitized to a Computer Aided Design (CAD) model by mesh representation. By advanced geometric tools, the mesh model can be changed easily following the user’s ideas. Those changes can be reflected to the clay model by robot machining. Furthermore, manual modifications on the existing clay model also can be added to the CAD model by 3-D scanning. For robot machining, a method based on 3-D scanning is used to calibrate the workpiece coordinate and the fixtures. Based on this system, virtual prototyping and physical prototyping can be achieved simultaneously. Solid or surface CAD models can be constructed directly from the mesh model after the prototyping stage. Experiments were made to demonstrate the effectiveness of the prototyping system. The possible applications in industrial product design are described as well.
Knowledge-Based Cost Estimation of Product Concepts
Authors: Welp E. G. , Giannoulis D.
Published: April 2009

A knowledge-based method for the cost estimation of concept variants for new or prototype products manufactured as unique-manufacture or in small batches-series. The goal is to provide design engineers of mechanical products with a method of which software implementation will enable them to perform easy, plausible cost estimations already in the very early development (concept) phases of product concepts or drafts. This will allow them to make prompt decisions about the most promising and cost-efficient concept for further development. Concurrently, the method will assist the designer in localizing the most cost-intensive concept or draft zones and in identifying the technical and process properties related to these costs. Hence, he will be able to concentrate on these characteristics and introduce an optimization procedure in the later detail design phase. Accordingly, the method is based on the principles of the systems engineering theory. Thereby, a “fundamental method element” is created. Based on this element, the application of the object-oriented design method leads to the creation of classes containing concept modeling elements with driving cost attributes concerning technical and process properties. The cost generation mechanism is then mapped in a class structure framework. In order to resolve the problem of the cost data vagueness and apply cost relationships in the concept phase, a fuzzy model is created to perform the cost estimation.
The Application of Value Stream Mapping to Lean Engineering
Authors: Pavnaskar Sandeep J. , Gershenson John K.
Published: April 2009

For the past few years, almost every manufacturing or service industry has been trying to get “lean.” The tools that enable waste elimination in engineering processes are equally important and little has been done to map the application of lean tools from manufacturing to the engineering process. Value stream mapping for manufacturing is a basic, graphical tool used to describe production processes and highlight sources of waste. In its current form, value stream mapping cannot be implemented in engineering processes due to fundamental differences between manufacturing and engineering processes. This paper identifies these differences as well as similarities between the manufacturing and engineering. We then use them to create analogies that enable the adaptation of value stream mapping for use in engineering. The application of this tool to engineering processes is validated by an industry application to manufacturing engineering processes, specifically the equipment installation process. With this map of the equipment installation process, our industrial team was able to identify wastes and sources of wastes, and design a future state where the lead-time of the installation process was reduced by over 90% with a much better first time quality.
Rapid Prototyping Through Octree Decomposition of 3D Geometric Models
Authors: Medelli´n H. , Corney J. , Davies J. B. C. , Lim T. , Ritchie J. M.
Published: April 2009

This paper presents the integration of an Octree modeller, an assembly planning system, and a robotic cell to build approximate prototypes directly from 3D model data. The integration demonstrates the feasibility of an assembly based rapid prototyping approach referred of as OcBlox, which approximates Octree representations of 3D models with “Blox”. These cuboid units are automatically assembled to obtain a physical prototype. After detailing the algorithms used to generate the Octree’s assembly sequence, a single resolution example of a prototype built with this automated system is presented. The paper ends with a discussion of the potential of the approach to support post build machining and complex overhanging geometry.
New Directions in Design for Manufacturing
Authors: Herrmann Jeffrey W. , Cooper Joyce , Gupta Satyandra K. , Hayes Caroline C. , Ishii Kosuke , Kazmer David , Sandborn Peter A. , Wood William H.
Published: April 2009

This paper gives an overview of research that is expanding the domain of design for manufacturing (DFM) into new and important areas. This paper covers DFM and concurrent engineering, DFM for conceptual design, DFM for embodiment design, DFM for detailed design, design for production, platform design for reducing time-to-market, design for system quality, design for life cycle costs, and design for environment. The paper concludes with some general guidelines that suggest how manufacturing firms can develop useful, effective DFM tools.
Integrated Synthesis of Assembly and Fixture Scheme for Properly Constrained Assembly
Authors: Lee Byungwoo , Saitou Kazuhiro
Published: April 2009

This paper presents an integrated approach to design an assembly, fixture schemes and an assembly sequence, such that the dimensional integrity of the assembly is insensitive to the dimensional variations of individual parts. The adjustability of critical dimensions and the proper constraining of parts during assembly process are the keys in achieving the dimensional integrity of the final assembly. A top down design method is developed which recursively decomposes a lump of initial product geometry and fixture elements matching critical dimensions, into parts and fixtures. At each recursion, joints are assigned to the interfaces between two subassemblies to ensure parts and fixtures are properly constrained at every assembly step. A case study on a simple frame structure is presented to demonstrate the method.
Design Process Error-Proofing: Project Quality Function Deployment
Authors: Chao Lawrence P. , Ishii Kosuke
Published: April 2009

This paper presents an advanced application of Quality Function Deployment (QFD) for product development projects. Design process error-proofing not only seeks to prevent catastrophic failures but also addresses product definition problems that compromise product features, time-to-market, or cost. Project QFD helps identify the organization requirements and flow them down to the activities, tools, and other solution elements for the project. This approach aids both product definition and resource allocation to clarify and strategically align project goals. The paper explains the method, illustrates it with an example, and discusses its effectiveness through a survey in industry and practical design projects at Stanford. The paper concludes with the proposed work to further disseminate this method.
A Methodology for Integrating Welding in DFA
Authors: Rule Robert , Stauffer Larry
Published: April 2009

A design for assembly worksheet is introduced that enables flexible accounting of assembly activities, especially welding. Welding activity is broken down into a variety of pre- and post-welding activities and the time penalty is estimated. This weld estimate is included into the traditional worksheet. This approach is especially useful for large complex products that are produced in small volumes where a significant portion of the assembly activity is through welding. These types of products often pose challenges for employing DFMA techniques cost effectively because of the increased engineering cost, divided among relatively few products, outweighs the potential benefits.
Testing Subjective Bias in the Analysis of the Customer Needs
Authors: Takai Shun , Ishii Kosuke
Published: April 2009

Collecting and grouping customer needs and constraints by similarity are essential steps in market-driven product development. This paper introduces an overall procedure to collect and structure customer needs and constraints with the emphasis on grouping customer needs by similarity. In particular, this paper applies a statistical methodology (Subjective Clustering) to test for an indication that a few participants’ opinions (information) dominate the others’ when grouping customer needs using the consensus-based method (Affinity Diagram). Biased use of participants’ information may lead to clusters inaccurately representing customer needs, which this paper defines as “subjective bias.” Using both Affinity Diagram and Subjective Clustering, one can test and correct the subjective bias while maintaining strong buy-in of the clusters by the participants.
Manufacturing Feature Based Dynamic Cost Estimation for Design
Authors: Patwardhan Harshal , Ramani Karthik
Published: April 2009

Due to the ever-increasing competition in today’s global markets, the cost of the product is rapidly emerging as one of the most crucial factors in deciding the success of the product. Decisions made during the design stage affect as much as 70–80% of the final product cost. Hence, a manufacturing cost estimation tool that can be used by the designer concurrently during the design phase will be of maximum benefit. A literature study of the available cost estimation tools suggests that a majority of these tools are meant for use in the later stages of the product development lifecycle. In the early stages of a product lifecycle, the only information that is available to the designer is related to geometry and material. Hence, the cost estimation methods that have been developed with the intent of being used in the early stages of design make use of the geometric information available at that stage of the design. Most of the earlier models that use parametric cost estimation and features technology consider the design features in their implementation. However, such models fail to consider “manufacturing based features” such as cores and undercuts. These manufacturing based features are very important in deciding the manufacturability and the cost of the part. The Engineering Cost Advisory System (ECAS) is a knowledge-based system that presents cost advice to the designer at the design stage after considering various design parameters and user requirements. Some of these design parameters can be extracted via standard Application Programming Interfaces (APIs). Moreover, ECAS uses innovative techniques of geometric reasoning and the hybrid B-rep-voxel model approach to extract manufacturing feature-based geometric information directly from the CAD input. By considering the manufacturing based features along with the design parameters, the ECAS architecture is applicable to a much wider variety of manufacturing processes. The complexity of the part, which is derived from the geometric parameters (manufacturing based and design based) and other non-geometric user requirements (e.g. quantity, material), is used to estimate the manufacturing effort involved in process specific activities. The final cost is then estimated based on this manufacturing effort and considering the hourly rates of labor and other contextual resources as well as material rates.
Incorporating Environmental, Quality and Economic Considerations Into Early Product Development Stage
Authors: Wang Bo , Ge Ping
Published: April 2009

Environmental impact is becoming an important consideration in product development, such as recycling in electronics industry and air pollution in automobile industry, besides product quality and economic growth. Incorporating the environmental impact consideration into business practice as early as possible can lead to direct impact on both strategic planning in a firm and the final product, which will benefit the firm and its customers. However, many different types of business activities and levels of decision-making involved at the early stage make the simultaneous consideration of environmental impact, quality and cost hard to render. An investigation on the existing research has shown that the activity-based cost/environmental model, in a uniform representation (activity), is useful in relating business activities to the performance measures in terms of cost and environment impact resulting from these activities. In this work, the authors argue about the needs and issues on explicitly integrating quality concern into the existing activity-based cost/environmental model. The expanded model, i.e., Three-View Activity-Based Model, is intended to help construct a clear road map to represent “what is going on?” and facilitate the measure of “how well are we doing?” in a business firm with product development involved. Product quality is treated as a driver as environment and cost for the activities, which enables quantitative performance assessment of the product quality related activities. As a result of introducing the quality driver, the need to differentiate the activities directly related to product development from other activities is identified. This has led to a study on the classification of the activities and their relationship to environmental impact, product quality, and cost objectives along a product development process with life cycle considerations. The three-view activity-based model may make it possible to evaluate the effectiveness of activities against these objectives at early product development stage, and therefore, recommend changes for reshaping a firm’s strategic planning and improving current practice. Since our investigation is still at its preliminary stage, in this paper, we will present our initial results, and address research issues for the future work.
Using Ecosystem Landscape Models to Investigate Industrial Environmental Impacts
Authors: Reap John , Bras Bert , Realff Matthew J. , Carmichael Carol
Published: April 2009

This article explores the use of ecosystem landscape models to estimate the environmental impacts of industrial activities at the regional / local scale. Integrated ecosystem and industrial modeling is first introduced within the context of life cycle assessment. Then, the use of integrated modeling to overcome problems stemming from the lumped parameter, static, site non-specific nature of life cycle assessment is discussed. Finally, the results of linking a handful of industrially relevant material and information flows demonstrate the ability of current ecosystem landscape models to respond to industrial burdens and estimate some environmental impacts.
A System Level Modeling for Sheet Metal Process Planning
Authors: Ramana K. V. , Rao P. V. M.
Published: April 2009

Modeling is to specify, visualize and document models of application systems including their structure before actual implementation. This paper attempts a system level modeling for sheet metal process planning for integration purposes. Many attempts have been made in the past proposing sheet metal process planning systems at implementation level based on product data models. However, process planning activity is knowledge intensive. An effective system is possible only if both data and knowledge models form a basis for it. This paper describes modeling a sheet metal process planning system before actual implementation, with data and knowledge models as a basis. Previous attempts at sheet metal process planning concentrated only on implementation and limited categories of data models. Moreover in these attempts data and knowledge models have been proposed without attempting to relate the two. The same have been over come in the present work. A frame work consisting of data and knowledge models for process planning is also proposed and discussed.
Customer Value Chain Analysis
Authors: Donaldson Krista M. , Ishii Kosuke , Sheppard Sheri D.
Published: April 2009

Customer Value Chain Analysis (CVCA) is an original methodological tool that enables design teams in the product definition phase to comprehensively identify pertinent stakeholders, their relationships with each other, and their role in the product’s life cycle. By performing CVCA, design teams are better able to recognize diverse product requirements and their relative priority for undertaking Product Definition Assessment and downstream Design for X (DfX) tools, such as Quality Function Deployment (QFD) and Failure Modes and Effects Analysis (FMEA). This paper discusses the evolution of the CVCA in response to the need for a DfX tool which is able to delineate customer needs early in the product development process. A step-by-step guide clarifies the implementation of CVCA with an example. Further, three case studies highlight the tool’s broad utility and important features to support design decision-making, including: 1) confirmation of the product’s business model, 2) recognition of the critical stake-holders, and 3) clarification of the value proposition to be embedded in the product.
Exploration of Local Blade Motions During Blade Shaping for Thick Layered Foam Cutting
Authors: Broek J. J. , Kooijman A.
Published: April 2009

The FF-TLOM (Free Form Thick Layered Object Manufacturing) technology is a Rapid Prototyping process based on flexible blade cutting of polystyrene foam. The heated blade is shaped by three parameters, which allows an infinite amount of minimum strain energy blade shapes with none, one or two inflexions. In the shaping domain stable and unstable blade shapes can exist. Stable shapes are defined as curves with none and one-inflexion and are applied for operational cutting of foam layers with the FF-TLOM technology. The tool motions are generated from the static tool poses and are calculated for a linear change of the flexible blade, when the cutting tool moves from one tool position to the next. The cutting blade is positioned to the foam slab with help of a point relative positioned on the flexible blade. The tool frame is positioned with a point fixed relatively to the tool frame. During the tool motions the blade curvature is changed and will introduce a shift of the half way point fixed on the blade (especially in the case of asymmetrical support inclinations and high curvature). Next the local displacement of the blade points in the bending plane of the blade due to blade shaping and tool pitching are quantified during the tool motions. These displacements induce an angle of attack of the blade in cutting direction, and will influence cutting speed and cutting accuracy. The quantification software is developed and will be used in the future for an overall prediction of the total tool curve displacements due to blade shaping, such as roll, pitch, yaw and linear positioning motions of the tool. A general rule for FF-TLOM cutting is minimization of all tool motions, which are not related to the forward cutting motion.
The YouTube Makeup Class
Authors: Haase David G.
Published: April 2009

When a college instructor goes out of town and must miss a lecture, the standard options are to cancel the class meeting or to enlist a colleague to fill in. In the former case a teaching opportunity is lost; in the latter the substitute may not lead the class in the same way as the instructor. Some students routinely skip lectures by a guest instructor, in the belief that the material in the substitute lecture will not be covered on the exam. There are other makeup options such as a directed study assignment. For instance, a missed class is sometimes a good opportunity to require students to investigate web-based simulations such as Physlets® that illustrate the class topics. These are most effective if the students are given a clear structure and if there are questions that the students must answer from their investigations with the Physlets. But many students are more comfortable with the audio and visual communication that occurs in the classroom. Web 2.0 technology, e.g., YouTube (http://www.youtube.com), makes it convenient for faculty to upload videos of lectures and demonstrations that can be used for makeup classes. College students already use YouTube for entertainment, and the YouTube format is simple to view on any web-connected computer. Although some universities have highly developed media delivery systems, YouTube is extremely convenient and accessible by anyone. This paper discusses how a YouTube makeup class can be efficiently produced and structured to be an effective learning experience.1
The Wondrous New World of Modern Particle Astrophysics
Authors: Hallin Aksel , Hallman Doug
Published: April 2009

To investigate the frontiers of particle physics, physicists and engineers are building detectors and making measurements in unusual settings from outer space to far-flung regions of the Earth. In the past several decades, laboratories have been set up deep underground in working mines or mountain tunnels to look at subatomic particles from our Sun and to search for the strange dark matter particles needed to explain the evolution of galaxies. This paper describes important current developments in astroparticle physics, the SNOLAB underground laboratory in Sudbury, Canada, and several of the experiments that are being developed in that facility.
A Graduation Stole Uniquely Designed for Physics
Authors: Day Lawrence H.
Published: April 2009

In response to student requests, and to help celebrate the graduation of our physics majors, we have designed a graduation stole uniquely befitting physics. The design incorporates the four visible spectral lines of hydrogen—the Balmer series. Since the 2002 debut of the design, all our graduates have proudly worn their physics graduation stoles at commencement. We hope the idea of a unique physics graduation stole, and the specific design of this particular one, will help spread the celebration of physics to other institutions as well.
A More General “U = mgh”
Authors: Keeports David
Published: April 2009

In problems dealing with the Earth's gravity, students are frequently bewildered by the fact that the two common expressions for potential energy, mgh and −Gmem/r, differ in sign and differ considerably in form. Some textbooks demonstrate that the more familiar first expression is a special case of the more general second equation providing that an object is near to the Earth's surface.1–2 In this paper I derive an equation that resembles the familiar U = mgh but that applies to an object of mass m at any height h above the Earth's surface.
Learning as They Write: An Assignment to Explain Physics Concepts
Authors: McKinney Julie , Hademenos George
Published: April 2009

Cross-curricular secondary instructional strategies exist in many different forms and can be applied to any two or more curricular disciplines. Most importantly, these strategies have been proven to be effective in improving learning and comprehension of important concepts across all curricular fields involved in the activity.1–7 There is no instructional strategy as applicable and as important to secondary students in all classes, particularly English Language Learners (ELLs),8,9 as the implementation of writing into a curricular discipline.
Double-Glazing Interferometry
Authors: Toal Vincent , Mihaylova Emilia M.
Published: April 2009

This note describes how white light interference fringes can be seen by observing the Moon through a double-glazed window. White light interferometric fringes are normally observed only in a well-aligned interferometer whose optical path difference is less than the coherence length of the light source, which is approximately one micrometer for white light. Obtaining such fringes in a Michelson interferometer is not a trivial task.1 The interferometer is typically illuminated with a monochromatic source and the path length difference adjusted with a wedge angle between the interferometer mirrors so that five or six vertical fringes are visible, indicating nearly equal paths. Then the mirrors are adjusted until the fringes are almost perfectly straight. Finally we use a white light source and carefully scan through the approximately equal path range until five or six white light fringes are seen to sweep rapidly by.
Physics Labs with Flavor
Authors: Agrest Mikhail M.
Published: April 2009

This paper describes my attempts to look deeper into the so-called “shoot for your grade” labs, started in the '90s, when I began applying my teaching experience in Russia to introductory physics labs at the College of Charleston and other higher education institutions in South Carolina. The term “shoot for your grade” became popular among teachers of a projectile motion lab where students are graded based on their ability to predict the range of the projectile. I describe here several additional laboratory exercises in which students are required to predict results of the experiment. I also discuss an essential element of these exercises which I call “recurrent study.”
Reaching Nonscience Students Through Science Fiction
Authors: Smith Donald A.
Published: April 2009

In 2006 I had the chance to design a physics course for students not majoring in scientific fields. I chose to shape the course around science fiction, not as a source for quantitative problems but as a means for conveying important physics concepts. I hoped that, by encountering these concepts in narratives, students with little or no science or math training might become more comfortable with them. I also thought the stories might provide the ideas with a context that would enable students to remember them more clearly than if they were reading a physics textbook.
Using a Michelson Interferometer to Measure Coefficient of Thermal Expansion of Copper
Authors: Scholl Ryan , Liby Bruce W.
Published: April 2009

When most materials are heated they expand.1 This concept is usually demonstrated using some type of mechanical measurement of the linear expansion of a metal rod.2 We have developed an alternative laboratory method for measuring thermal expansion by using a Michelson interferometer. Using the method presented, interference, interferometry, and the principle of thermal expansion can be taught concurrently. The material is accessible to undergraduates and advanced high school physics students.
The Grading Abyss
Authors: Ross Hugh
Published: April 2009

Editor's note: Hugh Ross is a physics teacher at Guerin Catholic High School in Noblesville, IN. He received his BS in aerospace engineering from Georgia Institute of Technology and his MS in aeronautical and astronautical engineering from Purdue University. After being drawn to the field of education, he later earned his MS in math and science education from Purdue University. Hugh also freelances as a science writer, developing test preparation manuals, science texts, and science test items.
Two-Color Single-Photon Photoinitiation and Photoinhibition for Subdiffraction Photolithography
Authors: Scott Timothy F. , Kowalski Benjamin A. , Sullivan Amy C. , Bowman Christopher N. , McLeod Robert R.
Published: April 2009

Subwavelength Patterning

Microscopists have recently achieved fluorescence imaging at subwavelength resolution by focusing one beam of light in a halo around another beam, thereby quenching the glow of fluorescent dyes in all but the very center of the illuminated spot. Three studies have now adapted this approach to photolithography (see the Perspective by

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(p.
917
, published online 9 April) coated a photo-resist with molecules that, upon absorbing the ultraviolet etching beam, isomerized to a transparent layer but returned to the initially opaque form upon absorption of visible light. Applying an interference pattern with ultraviolet peaks superimposed on visible nodes restricted etching to narrow regions in the center of these nodes, yielding lines of subwavelength width.

Scott
et al.

(p.
913
, published online 9 April) used a central beam to activate polymerization initiators, while using a halo-shaped surrounding beam to trigger inhibitors that would halt polymerization.

Li
et al.

(p.
910
, published online 9 April) found that use of a different initiator molecule allowed both beams to share the same wavelength (800 nanometers), with a relatively weak quenching beam lagging a highly intense initiating beam slightly in time. Both the latter techniques produced three-dimensional features honed to subwavelength dimensions.
Confining Light to Deep Subwavelength Dimensions to Enable Optical Nanopatterning
Authors: Andrew Trisha L. , Tsai Hsin-Yu , Menon Rajesh
Published: April 2009

Subwavelength Patterning

Microscopists have recently achieved fluorescence imaging at subwavelength resolution by focusing one beam of light in a halo around another beam, thereby quenching the glow of fluorescent dyes in all but the very center of the illuminated spot. Three studies have now adapted this approach to photolithography (see the Perspective by

Perry

).

Andrew
et al.

(p.
917
, published online 9 April) coated a photo-resist with molecules that, upon absorbing the ultraviolet etching beam, isomerized to a transparent layer but returned to the initially opaque form upon absorption of visible light. Applying an interference pattern with ultraviolet peaks superimposed on visible nodes restricted etching to narrow regions in the center of these nodes, yielding lines of subwavelength width.

Scott
et al.

(p.
913
, published online 9 April) used a central beam to activate polymerization initiators, while using a halo-shaped surrounding beam to trigger inhibitors that would halt polymerization.

Li
et al.

(p.
910
, published online 9 April) found that use of a different initiator molecule allowed both beams to share the same wavelength (800 nanometers), with a relatively weak quenching beam lagging a highly intense initiating beam slightly in time. Both the latter techniques produced three-dimensional features honed to subwavelength dimensions.
Development of a Second-Generation Antiandrogen for Treatment of Advanced Prostate Cancer
Authors: Tran Chris , Ouk Samedy , Clegg Nicola J. , Chen Yu , Watson Philip A. , Arora Vivek , Wongvipat John , Smith-Jones Peter M. , Yoo Dongwon , Kwon Andrew , Wasielewska Teresa , Welsbie Derek , Chen Charlie Degui , Higano Celestia S. , Beer Tomasz M. , Hung David T. , Scher Howard I. , Jung Michael E. , Sawyers Charles L.
Published: April 2009

A Second Act for Antiandrogens

Men with advanced prostate cancer are often treated with antiandrogens; drugs that inhibit the activity of male hormones, such as testosterone, that help drive tumor growth. Many of these drugs act by functionally disrupting the androgen receptor (AR), a transcriptional regulator of cell proliferation, but tumors eventually become resistant to the drugs by expressing higher levels of the AR.

Tran
et al.

(p.
787
, published online 9 April) have developed a “second-generation” antiandrogen, a thiohydantoin called MDV3100, which binds the AR with high affinity. MDV3100 retains its anticancer activity in cell culture and in mouse models even when AR levels are elevated. The drug appears to act both by inhibiting translocation of the AR into the nucleus and by reducing its transcriptional activity. MDV3100 is being tested in patients with advanced prostate cancer, the first group of which have shown a decline in blood levels of a marker of cancer growth, prostate-specific antigen.
Achieving λ/20 Resolution by One-Color Initiation and Deactivation of Polymerization
Authors: Li Linjie , Gattass Rafael R. , Gershgoren Erez , Hwang Hana , Fourkas John T.
Published: April 2009

Subwavelength Patterning

Microscopists have recently achieved fluorescence imaging at subwavelength resolution by focusing one beam of light in a halo around another beam, thereby quenching the glow of fluorescent dyes in all but the very center of the illuminated spot. Three studies have now adapted this approach to photolithography (see the Perspective by

Perry

).

Andrew
et al.

(p.
917
, published online 9 April) coated a photo-resist with molecules that, upon absorbing the ultraviolet etching beam, isomerized to a transparent layer but returned to the initially opaque form upon absorption of visible light. Applying an interference pattern with ultraviolet peaks superimposed on visible nodes restricted etching to narrow regions in the center of these nodes, yielding lines of subwavelength width.

Scott
et al.

(p.
913
, published online 9 April) used a central beam to activate polymerization initiators, while using a halo-shaped surrounding beam to trigger inhibitors that would halt polymerization.

Li
et al.

(p.
910
, published online 9 April) found that use of a different initiator molecule allowed both beams to share the same wavelength (800 nanometers), with a relatively weak quenching beam lagging a highly intense initiating beam slightly in time. Both the latter techniques produced three-dimensional features honed to subwavelength dimensions.
Cell Movements at Hensen’s Node Establish Left/Right Asymmetric Gene Expression in the Chick
Authors: Gros Jerome , Feistel Kerstin , Viebahn Christoph , Blum Martin , Tabin Clifford J.
Published: April 2009

Migration and Asymmetry

Although vertebrates show asymmetry in internal body organization, the earliest steps toward establishing different anatomies on the left and right sides are not conserved. How this is achieved in birds has been especially confusing.

Gros
et al.

(p.
941
, published online 9 April) show that in chicks some of the earliest left-right asymmetric domains of gene expression, including those of
Sonic hedgehog (Shh)
and
Fibroblast growth factor 8 (Fgf8)
, are produced passively. Genes are activated in bilateral cell populations, followed by rearrangements that shuffle
Shh
-expressing cells.