bluuebunny/crossref_metadata_2025_split huggingface dataset:
CAD Information Handling for Obtaining Dependable Manufacturing Systems
Authors: Miron E. , Mendonca J. P. , Machado J. , Olaru D. , Prisacaru G. 
Published: March 2016

The design of mechatronic systems is a multidisciplinary task that involves skills from mechanic, electronic and informatics areas. Recently, the expertise from such different fields is able to communicate and exchange the necessary contribution to successful design solutions, through a myriad of internet tools available. The introduction of internet of services on the design of mechatronic systems, mainly when teams, with different skills, operate in different geographic places, has contributed to flawlessly integrate better and interoperable final solutions. The design of mechatronic systems without errors — that operate without failures — is an important contribution to such goal. Safe behavior of mechatronic systems is crucial, mainly, in what concerns human safety. The correct behavior of those systems can be improved by the development of safe software for their controllers using some analysis techniques. Among them, Formal Verification (FV) is able to guarantee the best results. One of the main gaps using this technique is the difficulty of obtaining adequate plant models, in a systematic way, because this task is, usually, related with high level of expertise of designers and, in industry, this fact causes some difficulties for using those methods and tools. The work presented in this paper is a part of a larger project developed in the context of Software as a Service (SaaS) platform. It is intended to develop a systematized approach in order to obtain meaningful plant models out of existing CAD data, from Autodesk Inventor (or CATIA), and translate those models to formatted files according to input data of the UPPAAL model-checker (because it allows dealing with time variable).
The main idea is to obtain, systematically, plant models for Formal Verification purposes, considering that nowadays companies with different CAD systems are using increasingly often STEP-File format. A solution for this specific problem is explored and presented in this paper.
Dispersive Mixing Consideration of Twin-Screw Compounding Scale-Up Methodologies
Authors: Dryer Benjamin , Fukuda Graeme , Webb Jake , Bigio David I. , Wetzel Mark , Andersen Paul 
Published: March 2016

Twin-screw polymer extrusion has shown increased utility for creating composite materials. However, in order to achieve the desired product properties, sufficient mixing is essential. Dispersive mixing, or the breaking-up of particle agglomerates, is critical to create filled compounds with the required material properties. In a twin-screw compounding process, the Residence Stress Distribution (RSD) has been used to quantify the dispersive mixing induced by the stresses in the polymer melt. These stresses are quantified by the percent break-up of stress-sensitive polymeric beads. It was found that the amount of material that experiences the critical stress is a function of the operating conditions of screw speed and specific throughput [1]. The quantification of dispersive mixing allows for better control of a compounding process and can be used to design new processes.
During the development of a new compounding process, screw geometries and operating conditions are often refined on a laboratory-scale extruder and then scaled up to a manufacturing level. Scale-up rules are used to translate the operating conditions of a process to different sizes of extruders. In a compounding process, the goal when scaling-up is to maintain the same material properties on both scales by achieving equivalent mixing. The RSD methodology can be used to evaluate the effectiveness of scale-up rules by comparison between two or more scales.
This paper will demonstrate the utility of the RSD in evaluation of two unique scale-up rules. Conventional industry practice is based on the volumetric flow comparison between extruders. The proposed approach demonstrates that in order to maintain equivalent dispersive mixing between different sizes of extruders, the degree of fill, or the percent drag flow (%DF), must be kept equivalent in the primary mixing region. The effectiveness of both rules has been evaluated by experimental application of the RSD methodology. A design of experiment approach was used to generate predictive equations for each scale-up rule that were compared to the behavior of the original small-scale extruder.
Statistical comparison of the two scale-up rules showed that the %DF rule predicted operating conditions on the large-scale extruder that produced percent break-up behavior more similar to the small-scale behavior. From these results, it can be concluded that the %DF scale-up rule can be used to accurately scale operating conditions between different-sized extruders to ensure similar dispersive mixing between two processes. This will allow for greater accuracy when recreating the material properties of a small-scale twin-screw compounding process on a larger, mass production machine.
Tensile Properties of Polylactic Acid (PLA) Additive Manufactured Parts
Authors: Cardenas Joselyn , Stewart Calvin M. 
Published: March 2016

In the advancement of Additive Manufacturing (AM) technologies, 3D desktop printers have become an accessible solution to address the current manufacturing practices for most industries and the general public. This study explores the effect default build parameters have on the tensile properties of additive manufactured parts by comparing the Young’s Modulus and tensile strength of polylactic acid (PLA) in the elastic region before and after the AM process through experiments and numerical simulations. The build parameters are specified via MakerBot Desktop — the file preparation software for the MakerBot Replicator 3D printer used to create the specimens tested herein. This work presents the tensile mechanical properties for specimens built using low infill rate, low layer resolution, and standard build speed and extrusion temperature to recreate the worst possible part quality attainable using MakerBot 3D Desktop printers. Using these build parameters results in a part with a hollow honeycomb interior structure, and due to its heterogeneous cross sectional area, experimental stress-strain curves do not accurately represent its physical response to tensile loading. Therefore in this case, an experimental-numerical study of the 3D printed specimens is performed, using the load-displacement experimental data acquired from tensile tests to calibrate the ANSYS Structural Mechanics simulations. The goal is to optimize the material properties in our simulation such that the equivalent strain magnitude matches the experiments. This is an approach to determine the experimental Young’s modulus of PLA additive manufactured parts where the AM process, heterogeneous structure, and size greatly influence the part strength. This is completed by studying the worst part quality possible first to better understand this effect. Tensile tests are performed using an ADMET 5603 Universal Test Machine (UTM) synched with a Correlated Solutions 3D Digital Image Correlation (DIC) system. A fine heterogeneous speckle pattern is sprayed on the specimens and used by the DIC system to obtain surface contours of deformation. This data is compared to the displacement fields in the finite element analysis (FEA) simulation of the specimen.
When compared to the pre-manufacturing PLA, additive manufactured parts exposed that the post-processed stiffness of the material is increased when tested under this loading condition. The Poisson’s ratio for printed PLA was also noted to decrease when compared to pre-manufactured PLA, due to the larger longitudinal deformation compared to the transverse. Specimens failed by brittle fracture across the hex pattern, showing limited deformation and failing short after. The failure location based on the influence interior geometry has on failure showed that specimens failed by brittle fracture across the hex pattern, initiating fracture in the same region of all specimens.
Developing an Educational and Research Human Robot Interaction Environment for a Mechanical Finger/Hand
Authors: Ábrego Christopher E. , Shiakolas Panos S. , Sobhy Michael R. 
Published: March 2016

Human robot interaction (HRI) has become a growing area of study due to the increasing application of robots in work environments and daily life and interact and work in tandem with human operators. This synergy between humans and robots have expanded human endeavors and motivated neoteric and prospective areas of robotics research.
The objective of this research is to develop an environment where both researchers and students can experience and experiment with different interaction modes with a robotic finger and hand. The acquisition and the post processing of environmental data from the hardware allow the user to envisage decision making algorithms.
The present HRI environments have both closed and open loop controlled interaction modes for research and demonstration purposes. The interaction modes include direct open loop manipulation, force threshold interaction, voice commands, and variable force close. This additionally demonstrates the ease in functionality and augmentation in the testbed. As a result of speech recognition test, the testbed has a 79% success rate and has a 90% success rate in the force threshold test. The manuscript will also describe how certain actions are performed based on Prime States. An overview of the state algorithms are described as well as decision making diagrams.
Influence of Surface Energy in the Osteogenesis Process of Treated Titanium Surfaces
Authors: Sartini de Oliveira Lidiane , Amaral de Araújo Cleudmar , Lourenço de Souza Fernando , Mendonça Gustavo , Mendonça Daniela B. S. , Goulart Oliveira Sonia A. 
Published: March 2016

In the 1960’s, Brånemark and colleagues developed a dental implant system using a direct attachment to bone structure without generating soft tissue. This phenomenon called osseointegration involves biomechanical behavior of materials. In several studies it has been verified that the surface treatment on titanium implant has been the main factor for the osteogenesis process and, consequently, osseointegration [1, 2, 3]. Treated titanium surfaces have better conditions for cell adhesion that can lead to load application in the shortest time.
The aim of this study was to evaluate the surface energy and the cell osteogenesis on titanium discs under different conditions of blasting and acid attack. Osteoblastic cells Hfob 1.19 were used to measure cell culture parameters like cell viability and cell proliferation, alkaline phosphatase activity and mineralized nodule formation. Osteogenesis cell was defined through a mathematical model proposed by a similitude in engineering with osteogenic parameters analyzed in culture cells.
Fowkes Theory was used to calculate the surface energy by measuring contact angles between liquid sensors (Deionized Water, Chloroform) on different titanium surfaces.
Significant difference (P < 0,01) was observed for surface energies ranging between 26,76 a 33,81 mJ/m^2 using ANOVA and Bonferroni test. It was noted that the highest surface energies are related with osteogenesis levels.
MAAT Cruiser/Feeder Airship Design: Intrinsic Stability and Energetic Flight Model
Authors: Trancossi Michele , Dumas Antonio , Cimarelli Andrea , Pascoa Jose 
Published: March 2016

Airships are expected to have in future an increasing diffusion in the aeronautic scenario. The use of airships is not necessary expected to be the same proposed in the past. Several new uses will assume a relevant importance in the next 20 years. The resurgence of airships has created a need for dynamics models and simulation capabilities of these lighter-than-air vehicles. A theoretical framework for designing flexible airships has developed deriving the equations for determining the flight behavior of an airship directly form the data of wind tests and CFD simulations. This model has been a fundamental part of the final design activities of the MAAT (Multibody Advanced Airship for Transport) EU FP7 project, which has studied an innovative cruiser feeder airship based transport system. Main results relates to the definition of a specific mathematical model, which allow approximating the behavior of a flexible or low structured semi rigid airship in presence of external oscillations, in pitch or yawing. Different shapes of airships with different shapes, also not conventional, are assumed and aerodynamic behavior has been evaluated when slightly disturbed from steady forward motion or from hovering conditions in presence of an impacting wind. New uses and the exigency of adopting photovoltaic energy for long endurance missions, is producing airship shapes, which are slightly different from traditional Parsifal.
The model presents defines effective criteria based on constructal law, which allow designing an airship with an intrinsic stability in pitch and yaw. An approximate condition for a dynamically stable motion, such as unamplifying pitch, has been expressed in familiar aerodynamic quantities. These results allow stating the following theorem, which has been demonstrated: “Stable pitch flight conditions can be ensured if damping moment is in rotational equilibrium with the disturbing moment and if the disturbing force, the damping force, and the inertia force, are in translational balance”. If pitch angle and angular speed are small it can be obtained a relation that must be necessarily satisfied for ensuring a stability condition. An effective flight model based on energetic model of flight is also produced and results have been compared with traditional models giving a good accordance in terms of results.
Toward an Affordable Automation Scheme of Friction Stir Processing
Authors: Ammouri A. H. , Hamade R. F. 
Published: March 2016

Friction stir processing (FSP), an offshoot from friction stir welding (FSW), is an intricate operation that involves refining the material by a rotating tool. Active control of the resulting size and distribution uniformity of grain structure is desirable. Achieving such a control across the processed area requires real-time control of the process input variables in order to control the pertinent state variables (e.g., temperature, strain, and strain rate) throughout the process. Many active control schemes typically used in friction stir processes (such as position-, speed-, force-, and torque-control schemes) require the utilization of dynamometers to provide feedback to the control loop. Many drawbacks are associated with such utilization including the complexity of the required instrumentation and control systems. Another complexity is the required rigidity of the machine tool needed to perform friction stir processes.
In this work, we advance the notion of eliminating the usage of dynamometers by using the readily available motor current signals from the NC machine tool in the computer numeric control (NC) machines. This approach would drastically reduce the cost of FSP machine retrofitting. Presented in this work are guidelines for the implementation of affordable automation of CNC milling machines to perform friction stir processes. The guidelines are demonstrated by retrofitting a vertical machining center with current transducers to replace the usage of a dynamometer. The current transduces were tapped on the output of the drivers of the spindle and the z-drive motors. A custom LabVIEW software program was developed to control the machining center via direct numeric control mode and to monitor current signals which were in turn, correlated to the generated forces.
To demonstrate the methodology, friction stir processing was performed on magnesium alloy sheets for a wide range of process parameters. The tool rotational speed was varied from 600 RPM to 2000 RPM and the traverse feed from 75 mm/min to 900 mm/min. Current signals were monitored during frictions stir processing and were related to the process forces which were measured using a 4-component dynamometer. Linear relations between thrust force and torques with current signals of the spindle and the z-drive motors were established and the signal to noise ratio for each correlation was investigated.
It was found that the current spindle signals are highly correlated to the process torque where results can be used in a torque control loop without the need for expensive dynamometers. To a lesser extent was the correlation satisfactory between thrust force and z-drive motor signal due to bad signal to noise ratio.
Characterization of Micromist for Effective Machining
Authors: Li Qibo , Lerma Iram , Alvarado Jorge , Edinbarough Immanuel , Hung Wayne N. P. 
Published: March 2016

This study presents wetting characteristic of several lubricants for minimum quantity lubrication (MQL) by comparing their respective contact angles on different tool and workpiece materials. The size of an airborne droplet is estimated by measuring the profile of average droplets depositing on a polished and flat glass surface. The droplet velocity field in front of a nozzle is simulated numerically, and compared against measured data using anemometry and laser particle image velocimetry techniques.
A favorable contact angle of ∼5° is obtained for oil-based lubricants on titanium, stainless steel, and tungsten carbide samples. Such low contact angle is preferred over a higher contact angle of ∼30° typically found when using water-based cutting fluids. The micromist used in the study forms a conical flow of ∼ 20° in front of a coaxial nozzle. High air pressure can atomize lubricant into microdroplets with characteristics droplets of 4–11 μm in size, which are comparable with published data for microdroplet diameters. An optimum size of 3–5 μm microdroplets is preferred since airborne microdroplets below 2 μm may cause a health concern to some machine operators. When the input pressure is above 300 kPa, the air speed in front of a nozzle is at least 100 m/s (6,000 m/min) along a working distance of 20–100 mm from the nozzle tip. Since this droplet speed could be 5 times faster than the cutting speed of a diamond tool in ultrahigh speed machining, such microdroplet could penetrate the boundary layer of a fast rotating tool, adhere and wet the tool and workpiece surfaces for effective lubrication and heat removal. The axial microdroplet speed, however, is drastically reduced in the direction perpendicular to the flow due to vortices forming beyond ∼50 mm downstream from the nozzle tip. A single nozzle would be sufficient for a single point cutting tool — as in turning operation — if the working distance is short and the airstream is near the laminar regime, but multiple MQL nozzles should be utilized for a larger milling tool.
Enhancement of the Replication of Hepatitis C Virus Replicons of Genotypes 1 to 4 by Manipulation of CpG and UpA Dinucleotide Frequencies and Use of Cell Lines Expressing SECL14L2 for Antiviral Resistance Testing
Authors: Witteveldt Jeroen , Martin-Gans Marion , Simmonds Peter 
Published: March 2016

ABSTRACT

Treatment for hepatitis C virus (HCV) has improved greatly through the use of direct-acting antivirals (DAAs). However, their effectiveness and potential for drug resistance development in non-genotype 1 variants of HCV remain relatively unexplored, as
in vitro
assays to assess drug susceptibility are poorly developed and unsuited for a transient-transfection format. In the current study, we have evaluated the effects of dinucleotide frequency changes in the replicon and the use of a SEC14L2-expressing cell line on the replication of HCVs of different genotypes and evaluated the resulting assay formats for measurements of susceptibility to the DAA sofosbuvir. Removal of CpG and UpA dinucleotides from the luciferase gene used in HCV replicons of genotype 1b (Con1) and genotype 2a (JFH-1) achieved between 10- and 100-fold enhancement of replication over that of the wild type posttransfection. Removal of CpG and UpA dinucleotides in the neomycin gene or deletion of the whole gene in replicons of genotype 3a (S52) and genotype 4a (ED43) enhanced replication, but phenotypic effects on altering luciferase gene composition were minimal. A further 10-fold replication enhancement of replicons from all four genotypes was achieved by using a transgenic Huh7.5 cell line expressing SECL14L2, whose expression showed a dose-dependent effect on HCV replication that was reversible by small interfering RNA (siRNA) knockdown of gene expression. By combining these strategies, the 100- to 1,000-fold enhancement of replication allowed the susceptibility of all four genotypes to the RNA polymerase inhibitor sofosbuvir to be robustly determined in a transient-transfection assay format. These methods of replication enhancement provide new tools for monitoring the susceptibility and resistance of a wide range of HCV genotypes to DAAs.
Inhibitors of Ribosome Rescue Arrest Growth of Francisella tularensis at All Stages of Intracellular Replication
Authors: Goralski Tyler D. P. , Dewan Kalyan K. , Alumasa John N. , Avanzato Victoria , Place David E. , Markley Rachel L. , Katkere Bhuvana , Rabadi Seham M. , Bakshi Chandra Shekhar , Keiler Kenneth C. , Kirimanjeswara Girish S. 
Published: March 2016

ABSTRACT

Bacteria require at least one pathway to rescue ribosomes stalled at the ends of mRNAs. The primary pathway for ribosome rescue is
trans
-translation, which is conserved in >99% of sequenced bacterial genomes. Some species also have backup systems, such as ArfA or ArfB, which can rescue ribosomes in the absence of sufficient
trans
-translation activity. Small-molecule inhibitors of ribosome rescue have broad-spectrum antimicrobial activity against bacteria grown in liquid culture. These compounds were tested against the tier 1 select agent
Francisella tularensis
to determine if they can limit bacterial proliferation during infection of eukaryotic cells. The inhibitors KKL-10 and KKL-40 exhibited exceptional antimicrobial activity against both attenuated and fully virulent strains of
F. tularensis
in vitro
and during
ex vivo
infection. Addition of KKL-10 or KKL-40 to macrophages or liver cells at any time after infection by
F. tularensis
prevented further bacterial proliferation. When macrophages were stimulated with the proinflammatory cytokine gamma interferon before being infected by
F. tularensis
, addition of KKL-10 or KKL-40 reduced intracellular bacteria by >99%, indicating that the combination of cytokine-induced stress and a nonfunctional ribosome rescue pathway is fatal to
F. tularensis
. Neither KKL-10 nor KKL-40 was cytotoxic to eukaryotic cells in culture. These results demonstrate that ribosome rescue is required for
F. tularensis
growth at all stages of its infection cycle and suggest that KKL-10 and KKL-40 are good lead compounds for antibiotic development.