bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Ability of Structural and Phenomenological Hyperelastic Models to Predict the Mechanical Behavior of Biological Tissues Submitted to Multiaxial Loadings
Authors: Nierenberger Mathieu , Rémond Yves , Ahzi Saïd 
Published: August 2013

Medical surgery is currently rapidly improving and requires modeling faithfully the mechanical behavior of soft tissues. Various models exist in literature; some of them created for the study of biological materials, and others coming from the field of rubber mechanics. Indeed biological tissues show a mechanical behavior close to the one of rubbers. But while building a model, one has to keep in mind that its parameters should be loading independent and that the model should be able to predict the behavior under complex loading conditions. In addition, keeping physical parameters seems interesting since it allows a bottom up approach taking into account the microstructure of the material. In this study, the authors consider different existing hyperelastic models based on strain energy functions and identify their coefficients successively on single loading stress-stretch curves. The experimental data used, come from a paper by Zemanek dated 2009 and concerning uniaxial, equibiaxial and plane tension tests on porcine arterial walls taken in identical experimental conditions. To achieve identification, the strain energy function of each model is derived differently to provide an expression of the Cauchy stress associated to each loading case. Firstly the parameters of each model are identified on the uniaxial tension curve using a least squares method. Then, keeping the obtained parameters, predictions are made for the two other loading cases (equibiaxial and plane tension) using the associated expressions of stresses. A comparison of these predictions with experimental data is done and allows evaluating the predictive capabilities of each model for the different loading cases. A similar approach is used after swapping the loading types.
Since the predictive capabilities of the models are really dependent on the loading chosen to determine their parameters, another type of identification procedure is set up. It consists in adding the residues over the three loading cases during identification. This alternative identification method allows a better agreement between each model and the various types of experiments. This study evaluated the ability of some classical hyperelastic models to be used for a predictive scope after being identified on a specific loading type. Besides it brought to light some existing models which can describe at best the mechanical behavior of biological tissues submitted to various loadings.
Derivation of a New Model Including the Effect of Swelling on Finite Strain Properties for Polymeric Gels
Authors: Brulliard Violette , Verron Erwan , Le Corre Steven 
Published: August 2013

Polymeric gels consist in a cross-linked polymer chains network which contains a large quantity of solvent molecules. The main property of gels is their ability to absorb solvent molecules without being dissolved, and to shrink when they release fluid. This swelling/deswelling phenomenon involves large volume changes of the gel, when the solvent diffuses into the large strain elastic solid.
In recent literature, constitutive equations, in which the gel is considered as a single continuum body, have been derived to describe such a coupled deformation/diffusion problem. However, these works are based on the simple mono-dimensional models of both Flory and Treloar devoted to rubber swelling. The aim of the present work is the derivation of a new constitutive equation based on an original definition of the elastic strain energy. The differences with the classical theory are highlighted on two simple examples.
Comparison of Stress Distribution Pattern in Orthodontic Bracket- Adhesive- Tooth System During Treatment Time and Debonding Stage
Authors: Hajizadeh Maryam , Ghalichi Farzan , Mirzakouchaki Behnam , Shahrbaf Shirin 
Published: August 2013

Fixed orthodontic treatment is based on effective bonding of bracket to enamel surface. During orthodontic therapy, load is applied on bracket slot by orthodontic wire, and then it is transferred to adhesive layer and enamel surface (state I). After the completion of treatment period, orthodontic brackets are debonded by load application on the incisal region of bracket-adhesive interface (state II).
In order to compare the diversity in stress distribution pattern of these two states, micro CT images of maxillary premolar tooth and bracket were transformed to STL files and imported to Hypermesh software to create high quality 3D finite element models. Space between enamel and bracket was filled with orthodontic adhesive material which sets to 0.2 mm at thickest region. Mechanical property was assigned to each layer and appropriate boundary conditions were applied. By using a load distributing element RBE3, firstly 150 N shear load was applied on the bracket slot to simulate bracket-adhesive-tooth system of state I and secondly the same load was applied on the incisal area of bracket and bracket-adhesive bonding to simulate bracket-adhesive-tooth system of state II.
Generated stresses on the bracket, the adhesive and the tooth in both systems were obtained and compared to each other. The Findings of this study, reveal that the effect of bonding loads was directly transform to the adhesive layer and the enamel surface; hence, treatment period would decrease.
Alternatively, debonding loads would bring about higher stresses on the bracket and facilitate debonding action.
Laser Milling of Precision Mechanics for Space Instruments
Authors: Porter Jyri , Lappalainen Kauko 
Published: August 2013

This paper presents how laser milling can replace conventional milling for producing selected features in thin-walled structures of space instrument parts. Example parts are shown.
In the final stages of the manufacturing process the produced thin-walled structures require special attention to avoid vibration, unwanted deformation and even catastrophic destruction of the part. This requires careful planning of machining operations and fixture design which in turn can take considerable time.
Laser milling is a slow material removal process. It is generally used only for finishing features that normal chip cutting tools cannot reach. However, in the case of the part having thin-walled structures, laser milling has the extra benefit of causing practically no deflection or vibration due to machining forces and consequently it requires minimal fixturing.
Generally the laser beam should mill the material in the direction of its smallest depth to minimize recast and form errors that accumulate layer by layer. It is also possible to mill out solid chunks of material without fear of catastrophic collisions, unlike in chip cutting. This can reduce the milled volume thus speeding up the process considerably. Laser milling has special requirements with regard to the depth-width ratio of cavities, sidewall verticalness, and geometrical form of the raw stock. One must also consider where the laser beam hits after perforating the desired surface.
In many cases combining laser milling with traditional machining is the fastest way to produce one-of-a-kind parts.
Know What You Need to Know: The Role of Technological Knowledge in Product Service Systems
Authors: Thenent Nils E. , Settanni Ettore , Newnes Linda B. 
Published: August 2013

An emerging trend in defence and aerospace is the move from manufacturing and selling products to providing the availability of a product-related function based on long term contractual agreements between the customer and the service provider. Therefore the concern of the manufacturer as a service provider shifts towards all means that are required to ensure the availability of the product related function. This ultimately imposes the adoption of a broader perspective on a complex system of interconnected and interdependent activities undertaken by a diverse network of stakeholders for the achievement of a common purpose. Nonetheless, a consistent and comprehensive way to represent such complex systems is not yet agreed upon in the literature. For the purpose of estimating the costs of a Product Service System (PSS) delivery, a consistent and common representation of products and services is a necessary precondition.
The focus of this paper is to contribute to the debate by proposing the use of knowledge as the underlying foundation for representing products, services and PSS.
Building upon inter-disciplinary literature, differing concepts of PSS are discussed, in order to identify recurring aspects and commonalities between product and service. While it could be recognised that technology represents such a common element, it is also recognised that differing definitions of technology do not facilitate the discussion about product, service, and PSS. Instead, evidence is found for the argument that applied knowledge can be seen as the underlying foundation for products, service and PSS. In this sense, knowledge is not considered as a single asset, but rather a composition of different kinds of knowledge.
The authors propose the application of knowledge to a process-based approach, which facilitates the representation of products and services by overcoming their distinction in a consistent way. While the composition of knowledge related to each process is a necessary precondition to enable the successful delivery of a PSS, it furthermore requires knowledge about integration of all process inputs, outputs and the processes’ dynamics within a given environment. Herewith the focus shifts to the preconditions that enable the successful delivery of a PSS, such as available set of skills and underlying process understanding.
Discussing the role knowledge plays in current cost estimation methods it is found that — despite its importance — knowledge is not always clearly defined, and very often it is reduced to repository-based data retrieval systems.
The proposed knowledge-based process-orientated approach aims to facilitate investigating products, services, PSS, and the underlying production and delivery systems by representing them in a transparent and consistent way. While this is generally not bound to a particular type of analysis, the motivation originates from estimating the costs of a PSS delivery.
Designing a Networked Telerobotic System Using Internet
Authors: Tarca Radu , Cornea Mihai , Tarca Ioan , Vesselenyi Tiberiu 
Published: August 2013

Experimentation is a very important part of education in engineering including mechatronics engineering, which is a relatively new field, combining three engineering disciplines: mechanical engineering, electrical engineering and software engineering. The equipments needed for experiments in mechatronics are usually expensive. A solution to make these expensive equipments achievable is to share them with other universities or research centers from different locations in the world.
The goal of our team is to build a networked telerobot system so that the Internet users, especially researchers and students, can be able to control an autonomous robot able to explore a dynamic environment remotely from their home and share the robot system with the department. The particularity of the environment, in this case, is that the experiment uses grid lines painted on the floor, for robot navigation purpose.
The system which is still under development will be able to increase the number of robots. The communication software technologies are based on PHP. A specific protocol over IP was designed for communication between the server and clients.
The aim of this project is oriented toward providing a telerobot system with a high degree of local intelligence in order to overcome restricted bandwidth and transmission delay of the network.
The Effect of Cylinder Bore Distortion on Lube Oil Consumption and Blow-By
Authors: Kagnici Fatih , Akalin Ozgen 
Published: August 2013

It is well-known that cylinder bore deformations during engine operation cause a number of problems in piston ring lubrication. Particularly, the deterioration of piston ring and cylinder bore conformability results in a significant increase in lubricating oil consumption (LOC). Therefore, measurement and identification of cylinder bore distortion has been an important subject for engine designers.
In this study, an analytical lubricating oil consumption model was developed for a diesel engine. Piston stiffness was identified as an important input parameter for the oil consumption model, and the stiffness matrix of the piston was calculated using finite element simulations. In addition, finite element analysis was performed to determine the distorted cylinder block shape in engine running conditions. Pressure curves obtained in actual engine tests were used in the analysis. The Fourier coefficients of a distorted cylinder bore was calculated which characterize the deformed bore orders. Using these Fourier coefficients, several distorted bore shapes were regenerated, including a straight bore and the effect of each order on total lube oil consumption was investigated by means of the oil consumption model.
Gear Train Internal Dynamics in Large Offshore Wind Turbines
Authors: Rasekhi Nejad Amir , Xing Yihan , Moan Torgeir 
Published: August 2013

Today in the wind turbine global analysis codes such as Hawc2 [1] or FAST [2], the entire gear train is modelled by one degree of freedom constant stiffness torsional spring. This is because the focus in the global analysis programs lies mainly on the aerodynamic loads and the dynamic behaviour of structural members. For the small size gear trains, since the internal natural frequencies are expected in a frequency range above the overall wind turbine harmonics, this approach can be justified. However, as the industry trend is toward the larger drivetrains in offshore developments, the internal dynamic of gear trains are required to be modelled more accurately. Moreover, the development in generator technology with low, medium and high speed options has brought a variety of gear train design options with specific dynamic behaviour.
In this paper the natural modes and internal dynamic excitations of high ratio wind turbine gear trains is investigated. Case study gear trains of 0.6, 2, 5 and 10 MW are modelled by pure torsional elements in a Multi Body Simulation (MBS) program; Simpack [3], where the natural modes are obtained and possible excitation are evaluated. The results show the resonance trend in various size wind turbine gear trains.
Dose optimization in cardiac x‐ray imaging
Authors: Gislason‐Lee Amber J. , McMillan Catherine , Cowen Arnold R. , Davies Andrew G. 
Published: August 2013

Purpose:The aim of this research was to optimize x‐ray image quality to dose ratios in the cardiac catheterization laboratory. This study examined independently the effects of peak x‐ray tube voltage (kVp), copper (Cu), and gadolinium (Gd) x‐ray beam filtration on the image quality to radiation dose balance for adult patient sizes.Methods:Image sequences of polymethyl methacrylate (PMMA) phantoms representing two adult patient sizes were captured using a modern flat panel detector based x‐ray imaging system. Tin and copper test details were used to simulate iodine‐based contrast medium and stents/guide wires respectively, which are used in clinical procedures. Noise measurement for a flat field image and test detail contrast were used to calculate the contrast to noise ratio (CNR). Entrance surface dose (ESD) and effective dose measurements were obtained to calculate the figure of merit (FOM), CNR2/dose. This FOM determined the dose efficiency of x‐ray spectra investigated. Images were captured with 0.0, 0.1, 0.25, 0.4, and 0.9 mm Cu filtration and with a range of gadolinium oxysulphide (Gd2O2S) filtration.Results:Optimum x‐ray spectra were the same for the tin and copper test details. Lower peak tube voltages were generally favored. For the 20 cm phantom, using 2 Lanex Fast Back Gd2O2S screens as x‐ray filtration at 65 kVp provided the highest FOM considering ESD and effective dose. Considering ESD, this FOM was only marginally larger than that from using 0.4 mm Cu at 65 kVp. For the 30 cm phantom, using 0.25 mm copper filtration at 80 kVp was most optimal; considering effective dose the FOM was highest with no filtration at 65 kVp.Conclusions:These settings, adjusted for x‐ray tube loading limits and clinically acceptable image quality, should provide a useful option for optimizing patient dose to image quality in cardiac x‐ray imaging. The same optimal x‐ray beam spectra were found for both the tin and copper details, suggesting that iodine contrast based imaging and visualization of interventional devices could potentially be optimized for dose using similar x‐ray beam spectra.
Measurements of lateral penumbra for uniform scanning proton beams under various beam delivery conditions and comparison to the XiO treatment planning system
Authors: Rana Suresh , Zeidan Omar , Ramirez Eric , Rains Michael , Gao Junfang , Zheng Yuanshui 
Published: August 2013

Purpose: The main purposes of this study were to (1) investigate the dependency of lateral penumbra (80%–20% distance) of uniform scanning proton beams on various factors such as air gap, proton range, modulation width, compensator thickness, and depth, and (2) compare the lateral penumbra calculated by a treatment planning system (TPS) with measurements.Methods: First, lateral penumbra was measured using solid–water phantom and radiographic films for (a) air gap, ranged from 0 to 35 cm, (b) proton range, ranged from 8 to 30 cm, (c) modulation, ranged from 2 to 10 cm, (d) compensator thickness, ranged from 0 to 20 cm, and (e) depth, ranged from 7 to 15 cm. Second, dose calculations were computed in a virtual water phantom using the XiO TPS with pencil beam algorithm for identical beam conditions and geometrical configurations that were used for the measurements. The calculated lateral penumbra was then compared with the measured one for both the horizontal and vertical scanning magnets of our uniform scanning proton beam delivery system.Results: The results in the current study showed that the lateral penumbra of horizontal scanning magnet was larger (up to 1.4 mm for measurement and up to 1.0 mm for TPS) compared to that of vertical scanning magnet. Both the TPS and measurements showed an almost linear increase in lateral penumbra with increasing air gap as it produced the greatest effect on lateral penumbra. Lateral penumbra was dependent on the depth and proton range. Specifically, the width of lateral penumbra was found to be always lower at shallower depth than at deeper depth within the spread out Bragg peak (SOBP) region. The lateral penumbra results were less sensitive to the variation in the thickness of compensator, whereas lateral penumbra was independent of modulation. Overall, the comparison between the results of TPS with that of measurements indicates a good agreement for lateral penumbra, with TPS predicting higher values compared to measurements.Conclusions: Lateral penumbra of uniform scanning proton beams depends on air gap, proton range, compensator thickness, and depth, whereas lateral penumbra is not dependent on modulation. The XiO TPS typically overpredicted lateral penumbra compared to measurements, within 1 mm for most cases, but the difference could be up to 2.5 mm at a deep depth and large air gap.
Nontoxigenic Clostridium difficile Protects Hamsters against Challenge with Historic and Epidemic Strains of Toxigenic BI/NAP1/027 C. difficile
Authors: Nagaro Kristin J. , Phillips S. Tyler , Cheknis Adam K. , Sambol Susan P. , Zukowski Walter E. , Johnson Stuart , Gerding Dale N. 
Published: August 2013

ABSTRACT

Nontoxigenic
Clostridium difficile
(NTCD) has been shown to prevent fatal
C. difficile
infection in the hamster model when hamsters are challenged with standard toxigenic
C. difficile
strains. The purpose of this study was to determine if NTCD can prevent
C. difficile
infection in the hamster model when hamsters are challenged with restriction endonuclease analysis group BI
C. difficile
strains. Groups of 10 hamsters were given oral clindamycin, followed on day 2 by 10
6
CFU of spores of NTCD strain M3 or T7, and were challenged on day 5 with 100 CFU of spores of BI1 or BI6. To conserve animals, results for control hamsters challenged with BI1 or BI6 from the present study and controls from previous identical experiments were combined for statistical comparisons. NTCD strains M3 and T7 achieved 100% colonization and were 100% protective against challenge with BI1 (
P
≤ 0.001). M3 colonized 9/10 hamsters and protected against BI6 challenge in the colonized hamsters (
P
= 0.0003). T7 colonized 10/10 hamsters, but following BI6 challenge, cocolonization occurred in 5 hamsters, 4 of which died, for protection of 6/10 animals (
P
= 0.02). NTCD colonization provides protection against challenge with toxigenic BI group strains. M3 is more effective than T7 in preventing
C. difficile
infection caused by the BI6 epidemic strain. Prevention of
C. difficile
infection caused by the epidemic BI6 strain may be more challenging than that of infections caused by historic BI1 and non-BI
C. difficile
strains.
In VitroActivity of Fosfomycin against a Collection of Clinical Pseudomonas aeruginosa Isolates from 16 Spanish Hospitals: Establishing the Validity of Standard Broth Microdilution as Susceptibility Testing Method
Authors: Díez-Aguilar María , Morosini María-Isabel , del Campo Rosa , García-Castillo María , Zamora Javier , Cantón Rafael 
Published: August 2013

ABSTRACTThe broth microdilution method for fosfomycin andPseudomonas aeruginosawas assessed and compared with the approved agar dilution method in 206 genetically unrelatedP. aeruginosaclinical isolates. Essential agreement between the two methods was 84%, and categorical agreement was 89.3%. Additionally, Etest and disk diffusion assays were performed. Results validate broth microdilution as a reliable susceptibility testing method for fosfomycin againstP. aeruginosa. Conversely, unacceptable concordance was established between Etest and disk diffusion results with agar dilution results.
Microcalorimetry Assay for Rapid Detection of Voriconazole Resistance in Aspergillus fumigatus
Authors: Furustrand Tafin Ulrika , Meis Jacques F. , Trampuz Andrej 
Published: August 2013

ABSTRACT

We describe a calorimetric assay for detection of voriconazole-resistant
Aspergillus fumigatus
within 8 h. Among 27 genetically distinct strains, all 21 resistant and all 6 susceptible strains were correctly identified by measurement of fungal heat production in the presence of voriconazole. This proof-of-concept study demonstrates the potential of microcalorimetry for rapid detection of azole resistance in
A. fumigatus
.
Metagenomic Sequencing of Prokaryotic Microbiota from Tropical Surface Seawater
Authors: Chan Xin Yue , Arumugam Ramitha , Choo Siew Woh , Yin Wai Fong , Chan Kok Gan 
Published: August 2013

ABSTRACT
Tropical seawater harbors a rich diversity of microorganisms as a result of its nutrient-rich environment, constant supply of sufficient sunlight, and warm climate. In this report, we present the complexity of the microbial diversity of the surface seawater of the Georgetown coast as determined using next-generation sequencing technology.