bluuebunny/crossref_metadata_2025 huggingface dataset:
Grid-Based Scan-to-Map Matching for Accurate Simultaneous Localization and Mapping: Theory and Preliminary Numerical Study
Authors: Ryu Kunjin , Furukawa Tomonari , Antol Stanislaw , Dissanayake Gamini
Published: February 2014

This paper presents a grid-based scan-to-map matching technique for accurate simultaneous localization and mapping (SLAM). At every acquisition of a new scan, the proposed technique estimates the relative position from which the previous scan was taken, and further corrects its estimation error by matching the new scan to the globally defined map. In order to achieve best scan-to-map matching at each acquisition, the map to match is represented as a grid map with multiple normal distributions (NDs) in each cell. Additionally, the new scan is also represented by NDs, developing a novel ND-to-ND matching technique. The ND-to-ND matching technique has significant potential in the enhancement of the global matching as well as the computational efficiency. Experimental results first show that the proposed technique successfully matches new scans to the map generating very small position and orientation errors, and then demonstrates the effectiveness of the multi-ND representation in comparison to the single-ND representation.
Preliminary Investigation on Generating an Explicit GD&T Scheme From a Process Plan
Authors: Haghighi Payam , Vemulapalli Prabath , Mohan Prashant , Shah Jami J. , Davidson Joseph K.
Published: February 2014

Geometric Dimensioning and Tolerancing (GD&T) Standards have established a language for clear and concise specification of dimensional and geometric variations on manufactured parts. The language includes symbols for tolerance type, tolerance value, datum and reference frames, diameter and material condition modifiers and associativity with geometric entities. Designers use the standard to communicate their dimensional specifications to manufacturing and inspection personnel. However, process planners appear to be less formal in how tolerances are represented in process plans. Typically, they are shown only as dimensional plus/minus values. Datum Reference Frames (DRF) and geometric tolerance symbols are absent. It is believed that the latter are implicit in the set-up and fixturing prescribed in the plan. In this paper we explore how one might extract the implicit information systematically. The motivation for this effort is to verify the consistency of manufacturing tolerances with design specs and to be able to use the same tolerance analysis tools used in design. We discuss three research issues: extracting implied DRFs from set-ups and fixtures; converting plus/minus tolerances to appropriate geometric tolerances; and dealing with transient features — which are features that do not exist on the finished part used for GDT specs by the designer. We propose a new data structure, PCTF (process oriented constraint tolerance feature graph) to facilitate mapping between design and manufacturing tolerances.
A Limit Model for the Linear Dynamics of a Two-Layer Beam
Authors: Lenci Stefano , Rega Giuseppe
Published: February 2014

The asymptotic development method is used to study the effects of axial and rotational inertia, of shear deformations and of interface normal compliance in the vibrations of a two-layer beam. Starting from a model with Timoshenko kinematics, a model with Euler-Bernoulli kinematics for each layer, and with normal perfect adherence at interface, is obtained as a limit case. The limit model has only 1 unknown, versus the 8 of the original problem, and has only 2 dimensionless parameters, versus the 14 of the original problem, and thus it is much more easy. The asymptotic approach used to obtain the limit model guarantees on its reliability. Both the limit natural frequencies and their first order corrections are computed; the latter, in particular, permit to determine the sensitivity with respect to the considered parameters.
An MRI Coil-Mounted Multi-Probe Robotic Positioner for Cryoablation
Authors: Wu Faye Y. , Torabi Meysam , Yamada Atsushi , Golden Alex , Fischer Gregory S. , Tuncali Kemal , Frey Dan D. , Walsh Conor
Published: February 2014

Cryoablation is a percutaneous procedure for treating solid tumors using needle-like instruments. This paper presents an interventional guidance device for faster and more accurate alignment and insertion of multiple probes during cryoablation performed in closed bore magnetic resonance (MR) imaging systems. The device is compact and is intended to be mounted onto a Siemens 110 mm MR loop coil. A cable-driven two-degrees-of-freedom spherical mechanism mimics the wrist motion as it orients the intervention probes about a remote center of motion located 15 mm above the skin. A carriage interfaces with the probes via a thumbscrew-fastened latch to passively release the probes from their tracks, enabling them to be inserted sequentially and freeing them to move with respiration. Small actuator modules containing piezoelectric encoder-based motors are designed to be snap-fit into the device for ease of replacement and sterilization. The robot MRI compatibility was validated with standard cryoablation imaging sequences in 3T MR environment, yielding a maximum of 4% signal to noise ratio during actuator motion. Bench-level device characterization demonstrated a maximum error of 0.78° in the carriage movement. Needle-tip placement experiments for multiple targets in gelatin were performed using our image-guided navigation software, measuring an average targeting error of 2.0 mm.
Classifier-Guided Sampling for Discrete Variable, Discontinuous Design Space Exploration
Authors: Shahan David W. , Backlund Peter B. , Seepersad Carolyn C.
Published: February 2014

Estimation of density algorithms (EDAs) have been developed for optimization of discrete, continuous, or mixed discrete and continuous simulation-based design problems. EDAs construct a probability distribution on the set of highest performing designs and sample the distribution for the next generation of solutions. In previous work, the authors have demonstrated how classifier-guided sampling can also be used for discrete variable, discontinuous design space exploration. In this paper we develop the rationale for using classifier-guided sampling as a simple step beyond EDAs that not only improves the characterization of the highest performing designs but also identifies the poorly performing designs and exploits that information for faster convergence to optimal solutions. The resulting method is novel in its use of Bayesian priors to model the inherent uncertainty in a probability distribution that is based on a limited number of samples from the design space. The new classifier-guided method is applied to several example problems and convergence rates are presented that compare favorably to random search and a basic EDA implementation.
Examining Efficiency in Bioinspired Design
Authors: O’Rourke Julia M. , Seepersad Carolyn C.
Published: February 2014

In what ways and to what extent are bioinspired designs (BIDs) and the biological systems that inspire them ‘efficient’? The answer to this question provides insight into the potential role BID could have in the generation of energy- and materials-efficient designs. By qualifying and clarifying efficiency-related claims in the context of biological evidence, this paper contributes to the theoretical foundation for BID for efficiency and provides guidance to those developing design tools and methodologies aimed at using BID to enhance the efficiency of engineered products and systems.

This paper is organized into three main sections. First, a study is presented examining the reasons authors in the BID community cite when motivating their work. Of the 127 sources analyzed, 40 referenced ‘efficiency’, establishing empirically that efficiency of BIDs and the biological organisms that inspire them is a central motivation for work in BID.

Second, efficiency-related claims most commonly made by authors in BID are explained and analyzed using authoritative biological and BID literature. Ultimately, some of the claims prove problematic. However, when qualified appropriately, these claims provide significant insight into how the oft-cited examples of efficiency in biology and BID have arisen.

Finally, a study uncovering trends in sustainable BIDs is presented, and the efficiency-related trends are discussed. This study provides examples of some efficiency-related characteristics of biological systems that are successfully being transferred to engineered products and systems through BID. Specifically, the sustainable BIDs analyzed are shown to frequently meet four efficiency-related green design guidelines (GDGs) better than functionally-equivalent non-bioinspired alternatives. Additionally, passive mechanisms, multifunctional designs, and optimized geometries are discussed and shown to be prevalent in the sample of sustainable BIDs studied.
Development and Analysis of a New Specialized Gripper Mechanism for Garment Handling
Authors: Le Loan , Zoppi Matteo , Jilich Michal , Camoriano Raffaello , Zlatanov Dimiter , Molfino Rezia
Published: February 2014

This paper reports ongoing work on the design of a new gripper for garments handling. The development of this device is part of the CloPeMa European Project creating a robot system for automated manipulation of clothing and other textile items. First, we analyze the specificity of the application determining the requirements for the design and functioning of the grasping system. Textiles do not have a stable shape and cannot be manipulated on the basis of a priori geometric knowledge. The necessary exploration of the material and the environment is performed with the help of tactile sensors embedded in the fingertips of the gripper, complementing the vision system of the robotic work cell. The chosen design solution is a simple mechanism able to perform adequately the grasping task and to permit exploratory finger motions. The kinematics and statics of the mechanism are outlined briefly and, in accord with initial experiments, used to validate the design.
Application of Shape Memory Alloy (SMA) Based Actuation for Refreshable Display of Braille
Authors: Singhal Anshul , Jain Pranay , Chanana Piyush , Jain Dhruv , Paul Rohan , Balakrishnan M. , Rao P. V. M.
Published: February 2014

Persons with blindness access computers with the help of refreshable Braille displays and speech synthesis softwares. Braille has distinguished advantages over synthetic speech, especially because of its important role in uplifting education, employment and income. However, commercially available Braille displays are typically priced in the range of 2500–4000 USD (65–100 USD per Braille character) and are thus inaccessible to users in both developed and developing countries. Development of affordable Braille displays is thus a critical need.

Shape Memory Alloy (SMA) based actuation is a potential low-cost alternative to currently employed piezoelectric actuation, and is being used here to develop an affordable Braille display. This paper discusses key challenges identified in SMA based actuation and proposes methods to overcome the same. Prior attempts at developing tactile displays employing SMA based actuation are reviewed and important considerations for the present study are drawn. The configuration and the design of the actuator are thus arrived at. This paper further discusses the performance of fabricated prototypes and the feedback received from limited user trials. It concludes with a discussion on future scope of the work.
Theoretical and Experimental Study of an Harmonically Forced Vibro-Impact Nonlinear Energy Sink
Authors: Gourc Etienne , Michon Guilhem , Seguy Sébastien , Berlioz Alain
Published: February 2014

Recently, it has been demonstrated that a Vibro-Impact type Nonlinear Energy Sink (VI-NES) can be used efficiently to mitigate vibration of a Linear Oscillator (LO) under transient loading. In this paper, the dynamic response of an harmonically forced LO, strongly coupled to a VI-NES is investigated theoretically and experimentally. Due to the small mass ratio between the LO and the flying mass of the NES, the obtained equation of motion are analyzed using the method of multiple scales in the case of 1 : 1 resonance. It is shown that in addition to periodic response, system with VI-NES can exhibit Strongly Modulated Response (SMR). Experimentally, the whole system is embedded on an electrodynamic shaker. The VI-NES is realized with a ball which is free to move in a cavity with a predesigned gap. The mass of the ball is less than 1% of the mass of the LO. The experiment confirms the existence of periodic and SMR response regimes. A good agreement between theoretical and experimental results is observed.
Robust Supply Chain Network Design by Considering Demand-Side Uncertainty and Supply-Side Disruption
Authors: Rezapour Shabnam , Allen Janet K. , Trafalis Theodore B. , Mistree Farrokh
Published: February 2014

In this paper we propose a method that includes stochastic and robust models for designing the network structure of a three-tiered supply chain involving suppliers, manufacturers and retailers under random demands of markets and by considering disruption probabilities in the procurement facilities and connecting links of the chain. Demands of the markets are as assumed to be random variables with normal distribution and the disruption of the chain is formulated by defining different scenarios. Having substitutable facilities and extra production capacities makes it possible to overcome the negative effects of demand fluctuations and disruption of facilities. First we determine the optimal number, location and capacity of facilities in the first and third tiers and the best flow of material and product throughout the chain in a way to maximize the expected profit from the chain. Then to reduce the difference between the performances of the chain in different scenarios, we propose the ISP-Robust technique based on P-Robust technique to make the model robust. We discuss the differences and advantages of this technique in comparison to the P-Robust technique. We illustrate our method using data from the petrochemical industry.
A Task Driven Approach to Simultaneous Type Synthesis and Dimensional Optimization of Planar Parallel Manipulator Using Algebraic Fitting of a Family of Quadrics
Authors: Li Xiangyun , Zhao Ping , Ge Q. J. , Purwar Anurag
Published: February 2014

This paper studies the rigid body guidance problem for 3-DOF planar parallel manipulators (PPM) with three-triad assembly. We present a novel, unified, and simultaneous type and dimensional synthesis approach to planar parallel manipulator synthesis by using kinematic mapping, surface fitting, and least squares techniques. Novelty of our approach lies in linearization of a highly non-linear problem and the fact that the nature of the given motion or displacement drives the synthesis process without assuming triad topology or their geometry. It has been well established that by using planar quaternions and kinematic mapping, workspace related constraints of planar dyads or triads can be represented as algebraic constraint manifolds in the image space of planar displacements. The constraints associated with planar RR-, PR- and RP-dyads correspond to a single quadric in the image space, while that of each of the six planar triads (RRR, RPR, PRR, PPR, RRP and RPP) map to a pair of quadrics and the space between them. Moreover, the quadrics associated with RRR- and RPR-triads are of the same type as that of RR dyads, of PRR- and PPR-triads as that of PR-, and RRP- and RPP-triads as that of RP-dyad. This simplification nicely extends a dyad synthesis problem to a triad synthesis one. The problem is formulated as the least-squares error minimization problem to find a trinity of quadrics that best fit the image points of task displacements. The fitting error corresponding to each single quadric of the trinity is regarded as variation (thickness) of that quadric, which turns that quadric into a pair of quadrics. Hence, three dyads with minimal surface fitting errors can be converted to three triads in the Cartesian space.
A Concept Selection Framework for Early Sorting of Reconfigurable System Designs
Authors: Denhart Jason , Gemmer Thomas , Ferguson Scott , Mazzoleni Andre
Published: February 2014

A seven-step framework for sorting proposed concepts of system changes / reconfigurations is presented that seeks to characterize the overall ramifications on system architecture. This framework is intended for use immediately following a concept generation phase. The framework uses three simple questions: “What level of the system design does this concept apply to?” “What levels of the system design does the concept impact?” and “What is the severity of this impact?” A flowchart leads the designer through these questions and assigns each concept a classification from one to five based on the answers. Class one concepts have little to no impact on the rest of the system architecture. They can be included with little fear of massive change propagation and system redesign. Class five concepts carry large changes to system architecture and therefore should be included only if they can be shown to be highly beneficial, or if there remains enough design freedom such that the cost of changing the system architecture is minimal. Meanwhile, class five concepts are likely to have much higher potential to create revolutionary design. A case study is used to demonstrate the application of the sorting framework in the context of a Mars rover mission. Several example concepts are provided to illustrate key insights from the case study. Convergence of the framework is explored by comparing the authors’ results to a second test done by a new design team.
Radiation and Impedance Characteristics of a Circular Loop Antenna Driven by Fractional Order Electronics
Authors: Coopmans Calvin , Malek Hadi , Spencer Edmund
Published: February 2014

Fractional calculus techniques (non-integer order systems) have been successfully applied in many fields of electronics and engineering. In this paper the effects of including fractional order electronic components on the radiated antenna pattern of a circular loop antenna is presented. A fractional order “RLC” impedance matching circuit is placed between the generator and the equivalent circuit of a loop antenna. The input impedance of the antenna and the antenna gain are controllable through varying the fractional orders of an inductive element and a capacitive element (Fractors) in the matching network. The circuit is presented and solved analytically, and some numerical simulations follow. We discuss the effects of fractional order components on the resulting radiation patterns. In particular, the amplitude of the antenna gain is controlled by the fractional order parameters. This effect could be exploited in future for antenna beam-forming applications when using an array of antenna elements. Further, the input impedance of the antenna circuit can also be controlled by the fractional order components. The introduction of fractional order variables provides for higher degrees of freedom, enabling a flexible approach to tuning antennas for optimal performance.
Prioritizing the Many Measures of Success in Outsourced Design
Authors: Palm William J. , Whitney Daniel E.
Published: February 2014

Companies that develop new products increasingly outsource design, a trend that has prompted much concern but little prescription on how best to manage such projects. One challenge is the lack of understanding of what constitutes success in outsourced design. To provide clarity, this paper identifies academic and practical perspectives on success from the literature as well as our own interviews with design consultants and consulting clients, organizes the perspectives into a typology featuring seven distinct dimensions of success, and then prioritizes the key success measures using a survey of 194 additional practitioners. The results suggest that past research has generally focused on the wrong success measures, overstating the impact of problems during development and the relative importance of return on investment, and omitting key measures such as working relationship quality, project value, and client satisfaction. Not all success measures are well correlated; a project may do very well on some but poorly on others. While each measure has it merits, client satisfaction appears to be a promising summary measure.
Reminiscing: Educating Faculty of the Future
Authors: Allen Janet K. , Mistree Farrokh
Published: February 2014

Between 1992 and 2009 faculty in Georgia Tech’s Systems Realization Laboratory (SRL) mentored many students who are now pursuing successful careers in academia. In this paper the authors reminisce about the creation of the Systems Realization Laboratory at the Woodruff School of Mechanical Engineering at Georgia Tech and the mentoring of their former mentees (1992 through 2009) who are pursuing careers in academia. The author’s reminisces are augmented with reminisces of some of their former mentees. We hope that some of these ideas will be valuable to those who are setting up their own laboratories.
Chrono: A Parallel Physics Library for Rigid-Body, Flexible-Body, and Fluid Dynamics
Authors: Heyn Toby , Mazhar Hammad , Pazouki Arman , Melanz Daniel , Seidl Andrew , Madsen Justin , Bartholomew Aaron , Negrut Dan , Lamb David , Tasora Alessandro
Published: February 2014

This contribution discusses a multi-physics simulation engine, called Chrono, that relies heavily on parallel computing. Chrono aims at simulating the dynamics of systems containing rigid bodies, flexible (compliant) bodies, and fluid-rigid body interaction. To this end, it relies on five modules: equation formulation (modeling), equation solution (simulation), collision detection support, domain decomposition for parallel computing, and post-processing analysis with emphasis on high quality rendering/visualization. For each component we point out how parallel CPU and/or GPU computing have been leveraged to allow for the simulation of applications with millions of degrees of freedom such as rover dynamics on granular terrain, fluid-structure interaction problems, or large-scale flexible body dynamics with friction and contact for applications in polymer analysis.
Development of Model-Based Embedded Control Course Curriculum for Next Generation of Automotive Engineers
Authors: Chen Bo , Luo Wei , Agashe Pushkar , Feng Lei , Ge Zicheng , Li Yang
Published: February 2014

Hybrid Electric Vehicle (HEV) and pure Electric Vehicle (EV) are potential technologies to reduce fuel consumption and emissions in transportation sector. To educate next generation of automotive engineers with strong background in hybrid/electric drive vehicles, Michigan Technological University and partnering institutions General Motors, AVL, Argonne National Laboratory, Woodward, and MathWorks, have built an HEV/EV interdisciplinary program to develop curriculum for the education and outreach in transportation electrification.

Model-based design is emerging as an effective method to solve complicated control problems in automotive and aerospace industries. This paper presents the development of model-based embedded control course curriculum, one of the courses of Michigan Tech HEV/EV interdisciplinary program, to prepare students for their future career in automotive controls. The course goals, the development of teaching materials and associated laboratories, and the design of final project, are discussed. The developed course has been offered in Spring semesters since 2011 and received very positive feedback from students both in Mechanical Engineering – Engineering Mechanics (MEEM) and Electrical and Computer Engineering (ECE) Departments at Michigan Tech.
Energy Considerations for Fractional Elements
Authors: Lorenzo Carl F. , Hartley Tom T.
Published: February 2014

This paper considers the energy aspects of fractional elements defined by the equation Ft=kλDtλ0xt. In contrast to the typically conservative assumption of classical physics that lead to the potential and kinetic energy expressions, a number of important non-conservative differences are exposed. Firstly, the considerations must be time-based rather than displacement or momentum based variables. Time based equations for energy behavior of fractional elements are presented and example applications are considered. The effect of fractional order on the energy requirements and energy return of these systems is shown. Importantly, it is shown that the history, or initialization, has a strong effect on energy requirements. Finally, compact expressions for the work or energy, are developed.
Application of Viscous and Iwan Modal Damping Models to Experimental Measurements From Bolted Structures
Authors: Deaner Brandon J. , Allen Matthew S. , Starr Michael J. , Segalman Daniel J.
Published: February 2014

Measurements are presented from a two-beam structure with several bolted interfaces in order to characterize the nonlinear damping introduced by the joints. The measurements (at force levels below macro-slip) reveal that each underlying mode of the structure is well approximated by a single degree-of-freedom system with a nonlinear mechanical joint. At low enough force levels the measurements show dissipation that scales as the second power of the applied force, agreeing with theory for a linear viscously damped system. This is attributed to linear viscous behavior of the material and/or damping provided by the support structure, which simulates free-free boundary conditions. At larger force levels the damping is observed to behave nonlinearly, suggesting that damping from the mechanical joints is dominant. A model is presented that captures these effects, consisting of a spring and viscous damping element in parallel with a 4-Parameter Iwan model. The parameters of this model are identified for each mode of the structure and comparisons suggest that the model captures the linear and nonlinear damping accurately over a range of forcing levels.
From Discrete Vectors to Point Sets in Machining Simulations With High-Order Tool Surfaces
Authors: Aras Eyyup
Published: February 2014

In vector based machining simulations sampling only along one direction misses surface portions, such as sharp edges and vertical walls. This drawback can be removed when sampling along multiple directions, even without increasing the number of vectors. Therefore, given the same total number of vectors, vector hits are likely to be better distributed over the surface in a multiple-rayrep model than in a single one. But in this case, although we have a better in-process workpiece representation, we face with another problem: computational expense in the vector/envelope intersections. Computations are easy when the workpiece is represented by unidirectional vectors and when the tool axis is positioned along these vectors. On the other hand, a more complicated situation occurs when the machining simulations are performed in the multiple-reyrep based environments with tools having high-order geometries. In this case, the extensive usage of nonlinear root finding algorithms makes machining simulations impractical. One solution might be to eliminate the variable representing a vector from calculations. This leads to a union of 3D-points (i.e. polyhedral, voxel and Octree representations), at the loss of accuracy. Therefore, from a geometric viewpoint we can consider the aggregate of 3D-points as a special version of the multiple-rayrep model, in which the orthogonal vectors are discretized. In this paper, first the above mentioned drawbacks are presented for the triple-vector model based environments with arbitrarily oriented tool surfaces. Later, since each NC sequence is described by using the toolpath parameter, the above problems are reduced to a single equation with collection of toolpath parameters for the given 3D-points. Since its geometric complexity is highest among other APT-type cutter surfaces, the toroidal surface is chosen for the analysis.
Getting to the Novel Ideas: Exploring the Alternative Uses Test of Divergent Thinking
Authors: Kudrowitz Barry , Dippo Caitlin
Published: February 2014

The Alternative Uses Test is a measure of divergent thinking in which participants are asked to list non-obvious uses for a common object in a fixed amount of time. In this study, participants were asked to list alternative uses for a paperclip in three minutes. From a pool of over 2000 participants including engineering professionals and students, 293 were chosen and evaluated. Using infrequency of responses as a measure of novelty, it was found that participants that produced more responses had more novel responses and a higher average novelty score. Later responses were significantly more novel than early responses and unoriginality of responses decreased with quantity. On average, a participant would list 9 responses before arriving at highly novel responses. Participants that did not reach 9 responses in the study were likely to have few if any highly novel responses.

If this test maps to real world problem solving, it suggests that the first ideas we think of are likely to have been suggested already by others and thus not original. The results of this study can help restructure the format of the Alternative Uses Test.
Tools and Components of Wound Healing Assessment
Authors: Chin Jessica , Zeid Ibrahim , Kamarthi Sagar
Published: February 2014

Chronic wound assessment and analysis has long been a major healthcare issue. Chronic wound management and treatment cost billions of dollars each year. The research to alleviate the burden of non-healing wounds and predicting when they will heal is progressing at incremental pace. Characteristics of a chronic wound are unique to both the patient and wound itself. Like a fingerprint, each wound has a unique set of properties that tell a story about its health and viability. Although each person’s wound is individual, there are a few underlying pathologies that are common amongst all wounds. For example, all wounds have a definite surface area, depth, and temperature at any given time. By knowing these common characteristics across all wounds, we can use both historical data and collected data to determine wound healing patterns and wound healing rates. The purpose of this study is to develop an algorithm that uses photography and statistical modeling to predict an approximate wound healing rate for lower appendage wounds. We focus on lower appendage wounds with a depth of 1–2 mm because lower appendage wounds account for approximately 70% of wounds seen at wound clinics.
Towards the Design of a Fully Actuated Invertible Flying Quadrotor MAV
Authors: Gelardos Andreas , Cappelleri David J.
Published: February 2014

In this paper, we present the transmission mechanism design for a fully actuated Invertible Flying Quadrotor (IFQ) micro aerial vehicle (MAV). At the heart of the mechanism is a gearbox which couples and counter rotates two pairs of shafts that have the quadrotor propellers mounted at their ends. This mechanism will allow for the IFQ to follow aggressive maneuvers, hover at an arbitrary attitude, and have sustained inverted flight capabilities. The paper presents the mechanical design challenges and solutions in designing such a transmission mechanism with minimal weight along with low cost and easy manufacturing. The dynamic model for the IFQ MAV is presented along with an optimal open loop trajectory control scheme and related simulations. An approach for a full closed loop control scheme is also discussed. A prototype of the mechanism has been manufactured and functionally tested. The entire transmission mechanism was able to be prototyped with a weight of only approximately 100 grams.
Injections of Propidium Iodide Into HeLa Culture Cells Using a Nanoinjection Lance Array
Authors: Lindstrom Zachary K. , Brewer Steven J. , Easter Melanie A. , Jensen Brian D. , Burnett Sandra H.
Published: February 2014

Nanoinjection lance arrays have been used to inject propidium iodide, a dye, into living cells. The lance arrays consist of approximately four million needle-like structures on a 2 × 2 cm silicon chip, fabricated using standard methods for silicon wafers. A culture of HeLa cancer cells, commonly used in genetic research, has been employed for testing the nanoinjection process. Propidium iodide at several concentrations has been used as the dye for cell injection. The dye binds to nucleic acids after injection, and does not fluoresce when not bound, allowing accurate flow cytometry measurement of successful injections. Over 200 wells were tested to gather reliable testing data, consisting of negative controls (no treatment), positive controls (dye added with no injection), and samples (dye added and injection performed). Tests were performed for dye concentrations of 20, 40, 60, and 80 μL per 1 mL of cell media solution, for two different lance array geometries. The multi-cell nanoinjection process presented in this paper has proven to produce positive dye uptake results in injected cells while maintaining high cell viability, with an average uptake rate of about 52% for cells injected with the highest concentration of dye. Reviewing all data, the average sample success rate is 8 times higher than the rate of dye uptake in the positive controls. Cell viability in these tests is on average 96.2%. The process may be used in a variety of research areas.
Identifying the Material Information Requirements for Sustainable Decision Making
Authors: Narayanan Anantha , Witherell Paul , Lee Jae Hyun , Morris K. C. , Rachuri Sudarsan
Published: February 2014

Materials play a central role in product manufacturing, contributing to each phase of product development in the form of either a component or process material. As the product revolves around materials, so does much of the product information. Material information plays a significant role in the decision making process at any stage of the product life cycle, especially with respect to the sustainability of a product. Material information in the manufacturing stages of a product’s life cycle will relate to the processes used in manufacturing and assembling individual components. The material properties may determine what processes can be used and how these processes should be controlled.

To support sustainable manufacturing, the impacts of material choice should be considered during design, when resources are being committed. When comparing material alternatives at design time, it is not as simple as saying one material is “more sustainable” than another. Many different factors determine the sustainability of a product, and each of these factors may be influenced by multiple material properties represented through various information requirements. In order to develop a material information model that can satisfy these information requirements, we need to carefully study the requirements from an information modeling perspective. In this paper, we use activity models to describe design and manufacturing scenarios that rely on the availability of proper material information for sustainability decision making. We will use these models to first define specific scenarios and then to identify the types of material information that is typically required in these scenarios, and collect and categorize key concepts. Based on this study, we will make recommendations that will aid the development of a useful material information model for sustainable decision making.
Fabrication and Testing of Planar Stent Mesh Designs Using Carbon Infiltrated Carbon Nanotubes
Authors: Jones Kristopher , Jensen Brian D. , Bowden Anton
Published: February 2014

This paper explores and demonstrates the potential of using pyrolitic carbon as a material for coronary stents. Stents are commonly fabricated from metal, which has worse biocompatibilty than many polymers and ceramics. Pyrolitic carbon, a ceramic, is currently used in medical implant devices due to its preferrable biocompatibility properties. It can be created by growing carbon nanotubes, and then filling the space between with amorpheous carbon via chemical vapor deposition. We prepared multiple samples of two different stent-like flexible geometry designs out of carbon infiltrated carbon nanotubes. Tension loads were applied to expand the samples and we recorded the forces at brittle failure. These data were then used in conjunction with a nonlinear FEA model of the stent geometry to determine Youngs modulus and maximum fracture strain for each sample. Additionally, images were recorded of the samples before, during, and at failure. These images were used to measure an overall percent elongation for each sample. The highest fracture strain observed was 1.4% and Youngs modulus values confirmed the the material was the similar to that used in previous carbon infiltrated carbon nanotube work. The average percent elongation was 86% and reached as high as 145%. This exceeds a typical target of 66%.
Parallel Algorithm for Modeling Multi-Rigid Body System Dynamics With Nonholonomic Constraints
Authors: Mukherjee Rudranarayan , Malczyk Pawel
Published: February 2014

This paper presents a new algorithm for serial or parallel implementation of computer simulations of the dynamics of multi-rigid body systems subject to nonholonomic and holonomic constraints. The algorithm presents an elegant approach for eliminating the nonholonomic constraints explicitly from the equations of motion and implicitly expressing them in terms of nonlinear coupling in the operational inertias of the bodies subject to these constraints. The resulting equations are in the same form as those of a body subject to kinematic joint constraints. This enables the nonholohomic constraints to be seamlessly treated in either a (i) recursive or (ii) hierarchic assembly-disassembly process for solving the equations of motion of generalized multi-rigid body systems in serial or parallel implementations. The algorithm is non-iterative and although the nonholonomic constraints are imposed at the acceleration level, constraint satisfaction is excellent as demonstrated by the numerical test case implemented to verify the algorithm. The paper presents procedures for handling both cases where the nonholonomic constraints are imposed between terminal bodies of a system and the environment as well as when the constraints are imposed between bodies in the interior of the system topology. The algorithm uses a mixed set of coordinates and is built on the central idea of eliminating either constraint loads or relative accelerations from the equations of motion by projecting the equations of motion into the motion subspaces or their orthogonal complements.
Potential Methods for Prediction of Onset of Slip in Gait During the Transition From Double Support to Single Support
Authors: Gragg Jared , Yang James
Published: February 2014

This paper investigates two methods for the prediction of onset of slip in gait during the transition from single support to double support. The first method employs an optimization-based gait prediction simulation to determine the threshold of walking velocity that results in stable gait for one stride length and one subject. In order to determine the threshold, the simulation is carried out with progressively increasing walking velocities (initial conditions) until the gait becomes unstable. The zero moment point (ZMP) and support region are employed as criteria for stable gait, i.e. as long as the ZMP remains within the support region throughout the duration of gait, the gait is said to be stable. The second method employs a probabilistic simulation to predict the likelihood of slip, where the likelihood of slip is related to the available and required friction for gait.
Parallel Algorithm for Modeling Constrained Multi-Flexible Body System Dynamics
Authors: Mukherjee Rudranarayan , Laflin Jeremy
Published: February 2014

This paper presents an algorithm for modeling the dynamics of multi-flexible body systems in closed kinematic loop configurations where the component bodies are modeled using the large displacement small deformation formulation. The algorithm uses a hierarchic assembly disassembly process in parallel implementation and a recursive assembly disassembly process in serial implementation to achieve highly efficient simulation turn-around times. The operational inertias arising from the rigid body modes of motion at the joint locations on a component body are modified to account for the nonlinear inertial effects and body forces arising from the body based deformations. Traditional issues, such as motion induced stiffness and temporal invariance of deformation field related inertia terms, are robustly addressed in this algorithm. The algorithm uses a mixed set of coordinates viz. (i) absolute coordinates for expressing the equations of motion of a body fixed reference frame, (ii) relative or internal coordinates to express the kinematic joint constraints and (iii) body fixed coordinates to account for the body’s deformation field. The kinematic joint constraints and the closed loop constraints are treated alike through the formalism of relative coordinates, joint motion spaces and their orthogonal complements. Verification of the algorithm is demonstrated using the planar fourbar mechanism problem that has been traditionally used in literature.
Examining the Impact of Aggregated Design Impulses on Process Architecture in Distributed Design
Authors: Ghosh Sourobh , Devendorf Erich , Lewis Kemper
Published: February 2014

During the design of complex systems, a design process may be subjected to stochastic inputs, interruptions, and changes. These design impulses can have a significant impact on the transient response and converged equilibrium for the design system. We distinguish this research by focusing on the interactions between local and architectural impulses in the form of designer mistakes and dissolution, division, and combination impulses, respectively. We find that local impulses tend to slow convergence but systems subjected to dissolution/division impulses still favor parallel arrangements. The strategy to mitigate combination impulses is unaffected by the presence of local impulses.
Performance of Foldcores Mechanical Properties and Testing
Authors: Grzeschik Marc
Published: February 2014

Foldcores are folded open cellular structures which are currently under development at Institute of Aircraft Design (IFB). The IFB has generated an integrated manufacturing process to produce foldcores, starting with the mathematical methods to design the required foldcore geometry to the point of realizing them in an automated and continuous fashion. By isometric folding of planar base materials foldcores can and have already been manufactured out of a large variety of materials: cardboard, papers, metals (aluminum, steel, titanium), different thermoplastic films (PC, PVC, PPSU, PEEK) as well as advanced fibre reinforced materials (glass, carbon, aramid fibres).

For the technical use of foldcores in sandwich structures it is necessary to supply a competitive level of mechanical performance. We discuss the mechanical properties of foldcores compared to other state of the art core materials. We detail the testing methods used to determine compression and shear strengths and stiffnesses, which are based upon international standards. Evaluation of the test results show potential for the use of foldcores in high performance lightweight structures, especially considering their unique multifunctional applicability.
Experimental Blast Testing of a Large 9-Story Structure Equipped With a System of Nonlinear Energy Sinks
Authors: Wierschem Nicholas E. , Hubbard Sean A. , Luo Jie , Fahnestock Larry A. , Spencer B. F. , Quinn D. Dane , McFarland D. Michael , Vakakis Alexander F. , Bergman Lawrence A.
Published: February 2014

In recent years the protection of structures from blasts has gained widespread attention with most of the effort on this subject focused on mitigating the local effects of the blast. With improved local protection, controlling the global response of structures subjected to impulsive types of loads is becoming increasingly important. In this paper, the passive mitigation of a structure’s global response is examined through experimental blast tests of a large scale, 9-story structure equipped with a system of NESs. The system of NESs studied in this paper include two different types of devices, each of which employing a different type of restoring force; one type utilizes a smooth restoring force that is approximately cubic, while the other employs a linear restoring force coupled with one-sided vibro-impacts. The results of this study show that the passive NESs examined were capable of rapidly reducing the global response of the structure due to the blast loading. Additionally, the benefits of this passive system were demonstrated by its ability to reduce the peak demand on the structural system.
Numerical Integration Scheme Using Singular Perturbation Method
Authors: Gil Gibin , Sanfelice Ricardo G. , Nikravesh Parviz E.
Published: February 2014

Some multi degree-of-freedom dynamical systems exhibit a response that contain fast and slow variables. An example of such systems is a multibody system with rigid and deformable bodies. Standard numerical integration of the resultant equations of motion must adjust the time step according to the frequency of the fastest variable. As a result, the computation time is sacrificed. The singular perturbation method is an analysis technique to deal with the interaction of slow and fast variables. In this study, a numerical integration scheme using the singular perturbation method is discussed, its absolute stability condition is derived, and its order of accuracy is investigated.
Smooth Robust Subspace Based Model Reduction
Authors: Chelidze David
Published: February 2014

Long-time numerical simulations of large-scale mechanistic models of complex systems (e.g., molecular dynamics, computational fluid dynamics, structural finite element, or multi-body dynamics models) are still problematic, either due to numerical instabilities or the excessive necessary computational resources. Therefore, reduced models that can be simulated for long-time and provide truthful approximations to the actual long-time dynamics, are needed. A new framework — based on new concepts of dynamical consistency and subspace robustness — for identifying subspaces suitable for reduced-order model development is presented. Model reductions based on proper and smooth orthogonal decompositions (POD and SOD, respectively) are considered and tested using a nonlinear four-degree-of-freedom model. It is shown that the new framework identifies subspaces that provide accurate model reductions for a range of forcing parameters, and that only four and higher dimensional models could be dynamically consistent. In addition, for reduced-order models based on randomly driven data, a four-dimensional SOD-based model outperformed a five-dimensional POD-based model. Finally, randomly driven data-based models generally outperformed harmonically driven data-based models when tested for a wide range of forcing amplitudes.