scholarly journals Paradigm shifts in surface metrology. Part I. Historical philosophy

2007 ◽  
Vol 463 (2085) ◽  
pp. 2049-2070 ◽  
Author(s):  
X Jiang ◽  
P.J Scott ◽  
D.J Whitehouse ◽  
L Blunt
Keyword(s):  
Paradigm Shift ◽  
Free Form ◽  
Surface Metrology ◽  
Paradigm Shifts ◽  
Surface Geometry ◽  
Structured Surfaces ◽  
Manufactured Products ◽  
Philosophical Framework ◽  
Effective Development ◽  
Second World

Surface texture and its measurement are becoming the most critical factors and important functionality indicators in the performance of high precision and nanoscale devices and components. Surface metrology as a discipline is currently undergoing a huge paradigm shift: from profile to areal characterization, from stochastic to structured surfaces, and from simple geometries to complex free-form geometries, all spanning the millimetre to sub-nanometre scales. This paper builds a complete philosophical framework for surface metrology through a review of the paradigm shifts that have occurred in the discipline of surface metrology, tracing the development of fundamental philosophies and techniques. The paper starts with a brief overview of the historical paradigm shifts and builds an up-to-date foundational philosophy, capable of rapid and effective development. The growth in interest in surface metrology stems mainly from the need to control the manufacture of armaments during the Second World War and the production of domestic goods and appliances since that time. The surfaces produced by manufacture seemed to offer the possibility of being useful for process control. Unfortunately, only a few tentative investigations had been carried out to establish usable relationships between the processes, the machine tools and the available surface parameters (with their limitations). Even fewer investigations had been carried out to relate surface geometry to the performance of manufactured products. The result was that the metrology was unprepared and, consequently, the progress was sporadic. This overall review is given in two parts. Part I focuses on the historical philosophy of surface metrology and Part II discusses the progress within the current paradigm shift.

scholarly journals Paradigm shifts in surface metrology. Part II. The current shift

2007 ◽  
Vol 463 (2085) ◽  
pp. 2071-2099 ◽  
Author(s):  
X Jiang ◽  
P.J Scott ◽  
D.J Whitehouse ◽  
L Blunt
Keyword(s):  
Paradigm Shift ◽  
Functional Performance ◽  
Historical Context ◽  
Surface Metrology ◽  
Paradigm Shifts ◽  
Surface Geometry ◽  
Structured Surfaces ◽  
Geometrical Features ◽  
Ultra Precision ◽  
Current Shift

This is the second part of the paper ‘Paradigm shifts in surface metrology’. In part I, the three historical paradigm shifts in surface metrology were brought together, and the subsequent evolution resulting from the shifts discussed. The historical philosophy highlighted the fact that the paradigm shifts must be robust and flexible, meaning that surface metrology must allow for full control of surface manufacture and provide an understanding of the surface functional performance. Part II presents the current paradigm shift as a ‘stepping stone’, building on the above historical context. Aspects of surface geometry will also have to cater for surfaces derived from disruptive application, i.e. structured and freeform surfaces are identified candidates. The current shift is presented in three aspects: from profile to areal characterization; from stochastic to structured surfaces; and from simple geometries to complex freeform geometries, all spanning the millimetre to sub-nanometre scales. In this paradigm shift, the scale of surface texture is beginning to approach some of the geometrical features in micro/nano electro-mechanical systems devices and is becoming one of the most important functionality indicators. Part II will contextualize the current shifts in the discipline of surface metrology, and cement surface metrology in place in the ultra precision and nanotechnology age.

Micro- and Nano-instrument Power

2006 ◽  
Vol 973 ◽  
Author(s):  
Vassili Karanassios
Keyword(s):  
Signal Processing ◽  
Chemical Analysis ◽  
Data Acquisition ◽  
Cancer Diagnosis ◽  
Paradigm Shift ◽  
The Other ◽  
Paradigm Shifts ◽  
Comparable Performance ◽  
Wireless Interface ◽  
Capsule Size

ABSTRACTFor the last several years, we have been developing and characterizing “mobile” micro- and nano-instruments for use on-site (e.g., in the field). Although such portable, battery-operated instruments are much smaller that their laboratory-scale counterparts, sometimes they provide comparable performance and they often offer improved capabilities. As such, they are expected to cause a paradigm shift in classical chemical analysis by allowing practioners to “bring the lab (or part of it) to the sample”. Two classes of examples will be used as the means with which to illustrate the power of micro- and nano-instruments. One class involves a “patient” as the sample and an ingestible capsule-size spectrometer used for cancer diagnosis of the gastro intestinal tack as (part of) “the lab”. The other involves the “environment” as the sample and a portable, battery-operated, miniaturized instrument that utilizes a PalmPilot™ with a wireless interface for data acquisition and signal processing as (part of) “the lab”. To discuss how to electrically power such miniaturized instruments, mobile energy issues will be addressed. Particular emphasis will be paid to current or anticipated future applications and to the paradigm shifts that may prove essential in powering the next generation of miniaturized instruments.

scholarly journals Herring and ICES: a historical sketch of a few ideas and their linkages

2009 ◽  
Vol 66 (8) ◽  
pp. 1652-1661 ◽  
Author(s):  
Mike Sinclair
Keyword(s):  
Paradigm Shift ◽  
Pelagic Fish ◽  
Marine Ecology ◽  
Effective Management ◽  
Paradigm Shifts ◽  
Population Thinking ◽  
Fish Stocks ◽  
Considerable Debate ◽  
Historical Sketch

Abstract Sinclair, M. 2009. Herring and ICES: a historical sketch of a few ideas and their linkages. – ICES Journal of Marine Science, 66: 1652–1661. This introduction to the Symposium on “Linking Herring” sketches the development of some ideas generated from herring research within an ICES context. The work of Committee A (1902–1908), under the leadership of Johan Hjort, led to a paradigm shift from “migration thinking” to “population thinking” as the interpretation of fluctuations in herring landings. From the 1920s to the 1950s, the focus on forecasting services for the herring fisheries, although ultimately unsuccessful, had the unintended consequence of generating ideas on recruitment overfishing and the match–mismatch hypothesis. The collapse of the East Anglian fishery led, in 1956, to considerable debate on its causes, but no consensus was reached. Three consecutive symposia dealing with herring (1961, 1968, and 1970) reveal a changing perspective on the role of fishing on recruitment dynamics, culminating in Cushing’s 1975 book (“Marine Ecology and Fisheries”, referred to here as the “Grand Synthesis”), which defined the concept of recruitment overfishing and established the future agenda for fisheries oceanography. The 1978 ICES “Symposium on the Assessment and Management of Pelagic Fish Stocks” is interpreted as the “Aberdeen Consensus” (i.e. without effective management, recruitment overfishing is to be expected). In conclusion, herring research within ICES has led to many ideas and two major paradigm shifts.

Mechanistic Modeling of the Ball End Milling Process for Multi-Axis Machining of Free-Form Surfaces

2000 ◽  
Vol 123 (3) ◽  
pp. 369-379 ◽  
Author(s):  
Rixin Zhu ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor
Keyword(s):  
End Milling ◽  
Chip Thickness ◽  
Mechanistic Modeling ◽  
Free Form ◽  
Surface Geometry ◽  
Workpiece Surface ◽  
Ball End Milling ◽  
Modeling Approach ◽  
Free Form Surfaces ◽  
Cutting Point

A mechanistic modeling approach to predicting cutting forces is developed for multi-axis ball end milling of free-form surfaces. The workpiece surface is represented by discretized point vectors. The modeling approach employs the cutting edge profile in either analytical or measured form. The engaged cut geometry is determined by classification of the elemental cutting point positions with respect to the workpiece surface. The chip load model determines the undeformed chip thickness distribution along the cutting edges with consideration of various process faults. Given a 5-axis tool path in a cutter location file, shape driving profiles are generated and piecewise ruled surfaces are used to construct the tool swept envelope. The tool swept envelope is then used to update the workpiece surface geometry employing the Z-map method. A series of 3-axis and 5-axis surface machining tests on Ti6A14V were conducted to validate the model. The model shows good computational efficiency, and the force predictions are found in good agreement with the measured data.

scholarly journals Social Representations of the Environment in Press Media

2015 ◽  
Vol 25 (61) ◽  
pp. 261-269 ◽  
Author(s):  
Gislei Mocelin Polli ◽  
Brigido Vizeu Camargo
Keyword(s):  
Paradigm Shift ◽  
Social Representations ◽  
Representational Content ◽  
Environmental Issues ◽  
Paradigm Shifts ◽  
Qualitative Survey ◽  
The Press ◽  
Global Impacts ◽  
The Media ◽  
Over Time

Environmental issues are given prominence in the media and scientific circles. From the 60’s until early 2010 there were changes in the way people related to the environment, with a paradigm shift occurring regarding the environment. This study sought to identify the representational content disseminated by the press media on the environment in different periods. A qualitative survey was therefore conducted of documents, and data were obtained through texts published in a magazine with national circulation. The data were analyzed using the ALCESTE program with a Lexicographic Analysis. It was identified that the press media reflects the paradigm shifts, and publications dating from the late 60’s are compatible with the old paradigm, evolving over time, and are now compatible with the new environmental paradigm. The results indicate that currently the environment needs care in all its aspects and lack of care creates global impacts.

Tolerance Specification and Related Issues for Additively Manufactured Products

2015 ◽  
Author(s):  
Gaurav Ameta ◽  
Paul Witherell ◽  
Shawn Moylan ◽  
Robert Lipman
Keyword(s):  
Free Form ◽  
Complex Geometries ◽  
Geometric Accuracy ◽  
Current State ◽  
Manufactured Products ◽  
Internal Cavities ◽  
Tolerance Specification ◽  
Functional Features ◽  
Traditional Manufacturing ◽  
Am Processes

Additive manufacturing (AM) has gained increased attention in the last decade as a versatile manufacturing process for customized products. AM processes can create complex free-form shapes, introducing features such as internal cavities and lattices. These complex geometries are either not feasible or very costly with traditional manufacturing processes. This creates new challenges in maintaining and communicating dimensional and geometric accuracy of parts produced. In order to manufacture a product that meets functional needs, the specification of those needs through geometry, material and tolerances is necessary. This paper surveys the current state and needs of geometry related accuracy specification mechanisms for AM, including a review of specification standards such as ASME Y14.5 and ISO 1101. Emerging AM-related tolerancing challenges are identified, and a potential plan of action is put forth for addressing those challenges. Various issues highlighted in this paper are classified as (a) AM-driven specification issues and (b) specification issues highlighted by the versatility of AM processes. AM-driven specification issues include build direction, layer thickness, support structure related specification, and scan/track direction. Specification issues highlighted by the versatility of AM processes include, region-based tolerances for complex freeform surfaces, tolerancing internal functional features, tolerancing lattice and infills. Basic methods of solving these specification issues are also highlighted.

scholarly journals Can semiotics be used to drive paradigm changes in medical education?

2018 ◽  
Vol 46 (4) ◽  
pp. 491-516
Author(s):  
John Tredinnick-Rowe
Keyword(s):  
Medical Education ◽  
Paradigm Shift ◽  
Charles Sanders Peirce ◽  
Background Information ◽  
Paradigm Change ◽  
Threshold Concepts ◽  
Paradigm Shifts ◽  
Medical Educator ◽  
Situational Ethics ◽  
Scholastic Philosophy

This essay sets out to explain how educational semiotics as a discipline can be used to reform medical education and assessment. This is in response to an ongoing paradigm shift in medical education and assessment that seeks to integrate more qualitative, ethical and professional aspects of medicine into curricula, and develop ways to assess them. This paper suggests that a method to drive this paradigm change might be found in the Peircean idea of suprasubjectivity. This semiotic concept is rooted in the scholastic philosophy of John of St Thomas, but has been reintroduced to modern semiotics through the works of John Deely, Alin Olteanu and, most notably, Charles Sanders Peirce. I approach this task as both a medical educator and a semiotician. In this paper, I provide background information about medical education, paradigm shifts, and the concept of suprasubjectivity in relation to modern educational semiotic literature. I conclude by giving examples of what a suprasubjective approach to medical education and assessment might look like. I do this by drawing an equivalence between the notion of threshold concepts and suprasubjectivity, demonstrating the similarities between their positions. Fundamentally, medical education suffers from tensions of teaching trainee doctors the correct balance of biological science and situational ethics/ judgement. In the transcendence of mind-dependent and mind-independent being the scholastic philosophy of John of St Thomas may be exactly the solution medicine needs to overcome this dichotomy.

Fostering a Technology Cultural Change

2011 ◽  
pp. 240-246
Author(s):  
Dan Lim
Keyword(s):  
Higher Education ◽  
Information Technology ◽  
Cultural Change ◽  
Paradigm Shift ◽  
Education Institution ◽  
Paradigm Shifts ◽  
University Of Minnesota ◽  
Laptop Computing ◽  
Technology Commitment ◽  
The University

Many people in higher education wonder where the rapid changes in information technology are going to take them. Many more fear that the ongoing information technology explosion may eventually leave them behind. Due to entrenched mindsets and bureaucracy in higher education, fostering a technology cultural change requires paradigm shifts in all areas of administration, teaching, and research. A fundamental paradigm shift must happen in four areas before a technology cultural change can be set on a forward path. This chapter focuses on four essential components of a paradigm shift in technology and higher education at the University of Minnesota Crookston (UMC). This case describes how a paradigm shift model can help to promote a long-term technology cultural change in a higher education institution. The model consists of technology commitment, technology philosophy, investment priority, and development focus. It has been used at UMC to bring about a reengineering of the entire institution to support a ubiquitous laptop environment throughout the curriculum and campus. The model has helped UMC achieve an overwhelming success in utilizing laptop computing and other technology to enhance learning.

scholarly journals Eliminating the Effect of Reflectance Properties on Reconstruction in Stripe Structured Light System

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6564
Author(s):  
Zhao Song ◽  
Zhan Song ◽  
Yuping Ye
Keyword(s):  
Hybrid System ◽  
Surface Texture ◽  
Structured Light ◽  
Photometric Stereo ◽  
Free Form ◽  
Light Sources ◽  
Reconstruction Accuracy ◽  
Surface Geometry ◽  
Complex Objects ◽  
Structured Light System

The acquisition of the geometry of general scenes is related to the interplay of surface geometry, material properties and illumination characteristics. Surface texture and non-Lambertian reflectance properties degrade the reconstruction results by structured light technique. Existing structured light techniques focus on different coding strategy and light sources to improve reconstruction accuracy. The hybrid system consisting of a structured light technique and photometric stereo combines the depth value with normal information to refine the reconstruction results. In this paper, we propose a novel hybrid system consisting of stripe-based structured light and photometric stereo. The effect of surface texture and non-Lambertian reflection on stripe detection is first concluded. Contrary to existing fusion strategy, we propose an improved method for stripe detection to reduce the above factor’s effects on accuracy. The reconstruction problem for general scene comes down to using reflectance properties to improve the accuracy of stripe detection. Several objects, including checkerboard, metal-flat plane and free-form objects with complex reflectance properties, were reconstructed to validate our proposed method, which illustrates the effectiveness on improving the reconstruction accuracy of complex objects. The three-step phase-shifting algorithm was implemented and the reconstruction results were given and also compared with ours. In addition, our proposed framework provides a new feasible scheme for solving the ongoing problem of the reconstruction of complex objects with variant reflectance. The problem can be solved by subtracting the non-Lambertian components from the original grey values of stripe to improve the accuracy of stripe detection. In the future, based on stripe structured light technique, more general reflection models can be used to model different types of reflection properties of complex objects.

scholarly journals Successive Paradigm Shifts in the Bacterial Cell Cycle and Related Subjects

Life ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Vic Norris
Keyword(s):  
Cell Cycle ◽  
Steady State ◽  
Growth Rates ◽  
Bacterial Cell ◽  
Paradigm Shift ◽  
Eukaryotic Cell ◽  
Origins Of Life ◽  
Paradigm Shifts ◽  
Bacterial Physiology ◽  
Bacterial Cell Cycle

A paradigm shift in one field can trigger paradigm shifts in other fields. This is illustrated by the paradigm shifts that have occurred in bacterial physiology following the discoveries that bacteria are not unstructured, that the bacterial cell cycle is not controlled by the dynamics of peptidoglycan, and that the growth rates of bacteria in the same steady-state population are not at all the same. These paradigm shifts are having an effect on longstanding hypotheses about the regulation of the bacterial cell cycle, which appear increasingly to be inadequate. I argue that, just as one earthquake can trigger others, an imminent paradigm shift in the regulation of the bacterial cell cycle will have repercussions or “paradigm quakes” on hypotheses about the origins of life and about the regulation of the eukaryotic cell cycle.

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