bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comprehensive Algorithm for the Analysis of ECG Waveforms
Authors: Palliyali Abdul Jaleel , Tafreshi Reza , Mohsin Nasreen , Tafreshi Leyla 
Published: October 2013

This paper presents a comprehensive approach for the detailed analysis of ECG waveforms including various morphologies to aid clinical diagnosis. Clinical judgment is often based on observing various features which may occur simultaneously on the ECG. Thus, to automate diagnosis, a comprehensive tool capable of detecting all these features is required.
Parabolic curve fitting, adaptive thresholds and synchronicity across leads are utilized to detect the various waves of the QRS complex namely Q,R,S,R’ and S’. Onset of the QRS complex and the J point are detected using a ‘modified second derivative’ approach. The isoelectric level is detected using linearity and slope conditions. P and T waves are detected using ‘area under curve’ approach. Measurements such as peak-to-peak intervals and ST elevation/depression are numerically calculated from the points obtained. Curve fitting and change in slope are utilized for obtaining morphology of the ST segment. Presence of significant Q waves and abnormal T waves are inferred using clinical guidelines and numerical calculations.
The performance of the algorithm is validated on 40 sample patient data — 20 healthy and 20 with Myocardial Infarction. Average accuracy shown in detecting all points of interest is 98.5%. All measurements are successfully calculated from these points. Along with this reliable performance, the approach proves to be simple and computationally fast.
Air Handling Unit Level Fault Signature Development Using EnergyPlus
Authors: Song Li , Branesky Briana 
Published: October 2013

In the effort to create more energy efficient buildings, an effective fault detection process must be developed for monitoring and diagnosing malfunctions in the Heating Ventilation and Air Conditioning (HVAC) system. This study provides energy loss signatures that can be used to diagnose a specific faulty component at the unit level. An analysis has been performed on a single air handling unit (AHU) to determine how faulty HVAC components effect the overall energy consumption of the unit.
To begin the process, the Engineering Laboratory building on the campus of the University of Oklahoma was modeled for the simulation, using EnergyPlus 7.0, Google Sketchup 8, and OpenStudio 0.6.0. The building has an existing single duct system with a 3hp AHU with a forward curved fan that discharges 2500 cfm (1.175 m3/s) that covers approximately 2809 square feet (261 m2). Inputs into the simulation included building constructions, architecture, internal loads, and external loads from weather, sun, and shade objects. Simulations were run using the stated software, and a base case was established for energy consumption. Next, components and variables on the AHU, such as minimum outside air intake, economizer outside damper control, cooling coil valve, duct work pressurization, and various sensors were individually modified to reflect a malfunction or inefficiency. The energy loss caused from these changes in inputs was quantified and analyzed for the purpose of establishing a graphical range of energy loss signatures associated with each faulty component. Building Engineers and operators will be able to not only detect the exact malfunction faster, but also to ascertain the associated energy loss cost associated with the fault. The results of the study will be used to automate an online energy monitoring fault detection and diagnosis process.
How to Design and Create a Cardan Shaft for a Single Port Robot by Selective Laser Sintering
Authors: Roppenecker Daniel B. , Traeger Mattias F. , Gumprecht Jan D. J. , Lueth Tim C. 
Published: October 2013

With the spread of endoscopic interventions the postoperative stress for patients has been reduced clearly. These interventions through natural orifices of the body (Natural orifice transluminal endoscopic surgery: NOTES) need miniaturized instruments with high precision, high range of motion and a high force load transmission.
Our aim is to develop a mechatronic, single-port robotic system to guide and move flexible endoscopic instruments and optics inside the body. The system should be adapted to a flexible endoscope and consists of two flexible and actuated end-effectors that carry and manipulate flexible instruments. Due to the flexible end of the structure, laparoscopic single-port surgery through one incision and endoscopic surgery through a natural orifice would be possible. The concepts and prototypes were realized by selective laser sintering (SLS). One way to create flexible structures for a single use robot is to use universal joints assembled together in series. Next, selective laser sintering can now print these parts with the joints already assembled, in one part. There is no need for assembling or adhesive bonding. The final step is to replace the real joints of the cardan shafts with elastic joints.
The proposed joints are made by the powder PA 2200 based on nylon. This basic powder is certificated as biocompatible according to ISO 10993-1. The challenge in this new field of printed medical robotics is to define a manufacturing process that enables you to design a part, create it by SLS and get it approved as a medical product.
Capturing Assembly Constraints of Experimental Setups in a Virtual Laboratory Environment
Authors: Aziz El-Sayed , Chang Yizhe , Esche Sven K. , Chassapis Constantin 
Published: October 2013

Recently, multi-player game engines have been explored regarding their potential for implementing virtual laboratory environments for engineering and science education. In these developments, the virtual assembly process of the laboratory equipment is a critical step, and a detailed formalized description of how different components of the experimental equipment are to be joined in the assembly process is necessary. This description includes the joint types (lower and upper kinematic pairs) and the associated degrees of freedom, the resulting mobility of the assembly as well as the joint fit requirements.
In this paper, a formalized representation of the assembly process that captures the information on the joint kinematics and the components’ degrees of freedom generated when assembling laboratory equipment in a virtual laboratory environment will be discussed. A planetary gear train system will be used as an example to illustrate the proposed method. In particular, the structure of the assembly of a planetary gear train system involves assembly constraints between a group of components (sun, planet and ring gears, shafts, planet carrier assembly, etc.) that generate the desired relationship between the input and output motions. This paper will identify important requirements for modeling different configurations of planetary gear train assemblies within a game-based virtual laboratory environment. These requirements include the positioning and the orienting of the components, the verification of the kinematic joints, the propagation of the mating constraints and the capturing of the joint attributes.
Fast Converging Model for Load and Shear of Molecularly Thin Surface Films
Authors: Chong W. W. F. , Teodorescu M. 
Published: October 2013

Predicting the contact load and the shear losses in a narrow conjunction separated by a molecularly thin fluid layer must account for a significant number of factors: the chemical composition of the fluid and solid boundaries, the length of molecular chains, the intermolecular forces, the concentration of different species of molecules in the mixture, molecule-to-surface adsorption and surface topography. The most commonly used solutions to this problem either neglect a significant part of the participating phenomena or are computationally expensive (e.g. molecular dynamics simulations).
The current paper proposes a statistical mechanics model, which predicts the behavior of a molecularly thin film confined within a nano-scale conjunction. The advantage of this approach is that it is fast converging (semi-analytic) and all the aforementioned phenomena could be accounted for, within a single frame-work. The model is tested for an idealized bimolecular fluid and it was found that it can predict the influence of the packing fraction and the concentration ratio over the discontinuous discharge of fluid out of the a nano-scale conjunction.
The main application is accurate prediction of the shear stress-induced losses in a nano-scale contact (e.g. between asperities on opposite sides of a tribological conjunction) and modern drug delivery techniques (e.g. transdermal drug delivery patches).
A Physics-Based Modeling Approach of a Natural Gas HCCI Engine
Authors: AbdelGawad Marwa W. , Tafreshi Reza , Langari Reza 
Published: October 2013

Homogeneous Charge Compression Ignition (HCCI) Engines hold promises of being the next generation of internal combustion engines due to their ability to produce high thermal efficiencies, in addition to low nitric oxides and particulate matter. HCCI combustion is achieved through the auto-ignition of a compressed homogenous fuel-air mixture, thus making it a “fusion” between spark-ignition and compression-ignition engines. The main challenge in developing HCCI engines is the absence of a combustion trigger hence making the control of combustion timing difficult.
To be able to control ignition timing, a physics-based model is developed to model the full HCCI engine cycle while taking into consideration cycle-to-cycle transitions. Exhaust Gas Recirculation is used to control combustion timing while the temperature at intake valve closure will serve as the parameter that represents the desired ignition timing. The Modified Knock Integral model defines the necessary relationship between ignition timing and temperature at intake valve closure. Validation of the developed model is performed by determining the ignition timing under varying conditions. Results are shown to be in accordance with data acquired from a single-cylinder model developed using a sophisticated engine simulation program, GT-Power.
A Computer-Based Design System for Lightweight Grippers in the Automotive Industry
Authors: Petersson Håkan , Motte Damien , Eriksson Martin , Bjärnemo Robert 
Published: October 2013

This paper presents the development as well as the architecture of a computer-aided dedicated fixture design system intended to support the design of lightweight (carbon fiber composite) grippers for a major truck company. Lightweight grippers were required due to the increasing production rates in the automotive industry. The current robotic equipment was facing diverse problems during transportation and aligning of the parts, problems related to mass inertia, accuracy and stability. Moreover, the increased demands for truck customization and fast release of new product versions required a computer-based support for the design of the appropriate fixtures.
This application is believed to be of interest for fixture research because the design of such complex fixtures is likely to appear more and more often. Specifically, such fixtures are subject to specific requirements that necessitate a systematic requirement elicitation method; they also require extensive conceptual design work as well as careful analysis activity planning.
The main steps requisite for the development of the design system are reported: setup planning, fixture planning, conceptual design of the gripper. The architecture, the process and the constituent elements of the design system are also described and illustrated.
The Shockwave Response of Thin Composite Materials
Authors: Jahnke Douglas , Andreopoulos Yiannis 
Published: October 2013

Impingement of blast or shock waves on structures is characterized by a substantial transient aerodynamic load that develops over the short time associated with the shock reflection time scale. This mutual interaction between the shock wave and the structure can cause significant deformation of the structure and high strain rates within the material resulting in damage. An experimental investigation was carried out to determine the aeroelastic response of thin flat plates of composite materials during face-on impact with planar shock waves. The experiments were performed in a large-scale shock tube research facility, which had a working section of 12 inches in diameter and a length of 80 ft.
Phenolic composite S2-HJ1 plates of 1/8 inch nominal thickness consisting of 12 layers of fibers and epoxy composite S2 plates of 1/8 inch nominal thickness consisting of 10 layers of fibers were tested in the present investigation. Miniature semi-conductor strain-gauges of high frequency response, high speed photography and Digital Image Correlation techniques were employed to measure locally the strain on the exterior side of the plates and high frequency response pressure transducers were used to measure time-dependent wall and total pressure. In order to provide comparison with the response of monolithic material to similar compressive loadings, aluminum and stainless steel plates were also tested under the same conditions. The application of shock loading on the specimen causes significant permanent deformation on the plates which has been measured immediately after the experiment while the specimen is still mounted on the end flange of the shock tube. These experimental data obtained in the present experiments include the measured displacement of the external surface of the plates from their original position in the normal to the plate direction along the radius of the specimen. This displacement is highest at the center of the plate and zero at the location of clamping. The results show that the deformations of the thicker plates are still considerably lower than those obtained in the steel and thinner composite plates although the loading pressure is more than triple in magnitude and the corresponding impulse is about 2.3 times higher. Composite plates were found to suppress several of the modes of the wave patterns while metallic ones demonstrate a rich variety of interacting modes. The frequency content of the strain signals on the surface of composite plates was not always the same with the content of the surface acceleration measured in free vibration experiments.
Electrothermal Blinking Vortices for Chaotic Mixing
Authors: Loire Sophie , Kauffmann Paul , Gimenez Paul , Mezić Igor , Meinhart Carl 
Published: October 2013

Thanks to its favorable reduction scale law, and its easy integration, electrokinetics has emerged over the last fifteen years as one of the major solution to drive flows in fully integrated lab-on-chip. At microscale, an efficient mixing is a keystep which can dramatically accelerate bio-reactions. For thirty years, Dynamical System theory has predicted that chaotic mixing must involve at least 3 dimensions (either time dependent 2D flows or 3D flows). However, in microfluidics, few works have yet presented efficient embedded micromixers. This paper presents experimental and theoretical study of 2D time dependent chaotic mixing using AC electrothermal fluid flows. Experiments and numerical simulations are performed on a top view device and a sideview device. In both devices, a sinusoidal electric signal is applied between 3 interdigitated gold electrodes. A phase signal Vpp = 11V and a ground are switched between the two side electrodes using a step function, whereas the opposite phase signal –Vpp is steadily applied to the center electrode (Figure 1). Flow velocity is measured by micro particle image velocimetry μ PIV. The velocity profile shows a dramatic asymmetry between the two vortices. Therefore, during the switch, vortices overlap, leading to stretching and folding flows required to obtain chaotic mixing (Figure 3 and 4). The experimental measurements validate our electrothermal models based on our previous work [1]. The mixing efficiency of low diffusive particles is studied at multiscale using the mix-variance coefficient (MVC) [2] to evaluate mixing at different scales (Figure 4). To do so, the domain is successively divided in boxes along the x and y direction up to nx and ny boxes, respectively. For each box configuration, average bead concentration is computed. The variance of these concentrations is then evaluated: MVCs=1nxny∑i=1ny∑j=1nxρij-0.52. The result of numerically evaluated MVC in Figure 2 show a dramatic increase of mixing efficiency with blinking vortices compared to steady flow.
Theoretical, experimental and simulation results of the mixing process will be presented.
Simulation Based Optimization of Microfluidic Devices Used for Molecular Enrichment
Authors: Xia Hui , Mathew Bobby , Hegab Hisham , Feng June 
Published: October 2013

Microfluidic devices are used in several engineering fields ranging from biomedical to chemical to engineering for applications such as micro reactor, target molecular enriching and cell capturing. With regard to related applications, microfluidic devices offer advantages such as high surface area to volume ratio, increased mass transfer coefficient and portability in addition to their requirement of low analytes. Affinity based microfluidic devices with microscale posts have high compactness and mass transfer coefficient. In order to maximize the benefits offered by employing microfluidic devices, it is important to apply parametric study in the device designing work. This study is aimed at studying the operating and geometric parameters of microfluidic devices with square/rectangular microscale posts. The geometric parameters, such as aspect ratio of the microposts used, could possibly decide the performance of the device. Operating parameters studied are Reynolds number, Peclet number, Damköhler number, and equilibrium reaction constant. These parameters encompass the influence of velocity, diffusivity, density, viscosity, hydraulic diameter, inlet concentration of species and absorption/desorption reaction constants.
This work theoretically analyzes the influence of the above mentioned parameters using COMSOL Multiphysics 4.2.a. The governing equations of microfluidic devices, i.e. Navier-Stokes equations and the advection-diffusion equation, subjected to the above mentioned operating parameters, are solved to obtain the velocity profile, pressure drop and concentration profile of the species. The metric used for analyzing the influence of each operating parameter is the capture efficiency, i.e. the ratio of outlet concentration to inlet concentration as well the pressure drop. The results of this study would improve the design of microfluidic devices used for chemical reactions as well as that used for protein enrichment.
Analysis of Secondary Features From Visualization of Two-Phase Refrigerant Flow
Authors: Field Brandon S. 
Published: October 2013

Flow visualizations of refrigerant flows were made in a 0.5 mm glass channel. High speed videos of two-phase R134a flows were used to examine the secondary features within the two-phase flow and categorize the flow regimes present. Essentially, in small diameter channels, there are only two major observed flow regimes: inertia dominated (annular flow) and surface tension dominated (intermittent flow: slug or bubble). Image analysis was used to measure the velocities of the slugs and bubbles, and measurements of secondary features of the flow, such as the velocity of the surface waves that arose in slug-annular flow and the smaller bubbles that could be seen in the wakes of larger bubbles.
The secondary features of the two-phase flow are discussed with regard to their contribution to the flow regimes that are observed as the flow moves through the channel. Rings of liquid were observed to form into liquid slugs, dividing the longer bubbles into two. This is believed to be one of the transition mechanisms between the two flow regimes. Small droplets were also observed within the vapor core, which demonstrated velocity gradients within the vapor bubbles. Velocity measurements of the secondary features within the liquid films are used in the analysis of the dynamics within these flows that lead to pressure drop and flow regime transition.
Responsible Conduct of Research in Computational Modeling
Authors: Wilson Sara E. , Keefer Matthew W. , Dankowicz Harry , Loui Michael C. 
Published: October 2013

Computational modeling is a growing area of mechanical engineering that focuses on the use of numerical simulation to examine complex phenomena. Computational modeling includes work in finite element analysis, computational fluid dynamics, and multi-body dynamics modeling. Intrinsic to most of these modeling efforts are common elements including:
1. Assumptions that are made to reduce a problem to a solvable mathematical problem,
2. Formulation of a mathematical representation based on scientific principles,
3. Reduction of the mathematical representation through the removal of terms of small effect (neglected terms)
4. Collection and use of input data,
5. Algorithm development using numerical methods and discretization of the mathematical problem,
6. Implementation of the algorithm in computer code,
7. Creating representations of the model results,
8. External validation of the model, and
9. Dissemination of the model and model computer code.
Performance and Economic Analysis of Biomass/Coal Co-Gasification IGCC Systems With Supercritical Steam Bottom Cycle: Part 2 — Pre-Combustion Carbon Capture
Authors: Wang Ting , Long Henry A. 
Published: October 2013

One of the main advantages of IGCC technology is that it is the only form of power generation that is compatible with pre-combustion carbon capture. Part 2 of this paper will thus focus on analyzing pre-combustion CCS, utilizing both sour-shift and sweet-shift processes and comparing them to each other and to the results of post-combustion CCS from Part 1. Pre-combustion CCS plants are smaller than post-combustion ones, and usually require 25% less energy for CCS due to their compact size for processing fuel flow only under higher pressure (450 psi), versus processing the combusted gases at near-atmospheric pressure. For pre-combustion CCS, sour-shift appears to be superior both economically and thermally to sweet-shift in the current study. Sour-shift is always cheaper, (by a difference of about $600/kW and $0.02-$0.03/kW-hr), easier to implement, and also 2–3 percentage points more efficient.
Adding biomass to the system always reduces the emissions and can even make a plant carbon-negative with as little as 10% biomass by weight. In addition, the efficiency will improve (0.7 points) and power output will also improve (∼1%–3% more) for up to 10% biomass ratio (BMR) for the right kind of biomass that has been properly pretreated. Beyond 10% BMR, however, the efficiency begins to drop due to the rising pretreatment costs, but the system itself still remains more efficient than from using coal alone (between 0.2–0.3 points on average). The economic difference is fairly marginal, but the trend is inversely proportional to the efficiency, with CoE decreasing by 0.5 cents/kW-hr from 0%–10% BMR and rising 2.5 cents/kW-hr from 10%–50% BMR. Finally, the CO2 removal cost for sour-shift is around $20/ton, whereas sweet-shift’s cost is around $30/ton, which is much cheaper than that of post-combustion CCS from Part 1: about $60-$70/ton.