Palpation Sensitivity of an Embedded Nodule Using the Finite Element Method

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Abhishek Mukherjee ◽  
Abhishek Gupta ◽  
Shamik Sen ◽  
Wenyi Yan ◽  
Anil Saigal ◽  
...  
Keyword(s):  
Physical Properties ◽  
Material Properties ◽  
Indentation Depth ◽  
Finite Thickness ◽  
Material Model ◽  
Healthy Tissue ◽  
Detection Sensitivity ◽  
Critical Parameters ◽  
Tumor Nodule ◽  
Depth Increase

Abstract A physician palpates a tissue to detect an embedded tumor nodule by sensing an increase in local tissue stiffness and nodule size. The Hertz contact model, however, is unable to predict the material or physical properties of a tumor nodule embedded in a healthy tissue of finite thickness. In this study, utilizing a hyperelastic material model, we propose a general methodology to analyze the extent to which the stiffness, size, and depth of a nodule embedded in a tissue affect its detectability. Using dimensional analysis, we generate simple power-law relations to predict physical and material properties of tumor nodules embedded in healthy tissue during indentation. Our results indicate that indenter radius and indentation depth are critical parameters in nodule detection and a thin indenter and large indentation depth increase detection sensitivity of an embedded tumor nodule. Our results also show that anisotropic material properties of either a tissue or an embedded nodule render the embedded tumor nodule undetectable using indentation. We define palpation sensitivity maps that can be used to predict material and physical properties of tumor nodules in healthy tissues. The analysis and results presented in this study might increase accuracy and precision in instrumented probe-based laparoscopic or robotic surgeries.

Finite Thickness Influence on Spherical and Conical Indentation on Viscoelastic Thin Polymer Film

2005 ◽  
Vol 127 (1) ◽  
pp. 33-37 ◽  
Author(s):  
V. Gonda ◽  
J. den Toonder ◽  
J. Beijer ◽  
G. Q. Zhang ◽  
L. J. Ernst
Keyword(s):  
Polymer Film ◽  
Material Properties ◽  
Finite Thickness ◽  
Thin Polymer Film ◽  
Spherical Indentation ◽  
Infinite Plane ◽  
Precise Knowledge ◽  
Thin Polymer ◽  
Measurement Results ◽  
Conical Indentation

The thermo-mechanical integration of polymer films requires a precise knowledge of material properties. Nanoindentation is a widely used testing method for the determination of material properties of thin films such as Young’s modulus and the hardness. An important assumption in the analysis of the indentation is that the indented medium is a semi-infinite plane or half space, i.e., it has an “infinite thickness.” In nanoindentation the analyzed material is often a thin film that is deposited on a substrate. If the modulus ratio is small, (soft film on hard substrate) and the penetration depth is small too, then the Hertzian assumption does not hold. We investigate this situation with spherical and conical indentation. Measurement results are shown using spherical indentation on a visco-elastic thin polymer film and a full visco-elastic characterization is presented.

Initial Assessments of a Handheld Indentation Probe's Correlation with Cancellous Bone Density, Stiffness and Strength: An Objective Alternative to 'Thumb Testing'

2021 ◽  
Author(s):  
Jacob Reeves ◽  
Tom Vanasse ◽  
Christopher Roche ◽  
Kenneth J. Faber ◽  
G. Daniel G. Langohr
Keyword(s):  
Compressive Strength ◽  
Bone Density ◽  
Impact Energy ◽  
Material Properties ◽  
Indentation Depth ◽  
Strong Correlations ◽  
Bone Properties ◽  
Depth Scale ◽  
Correlation Strength ◽  
Metaphyseal Bone

Abstract During shoulder arthroplasty, surgeons must select the optimal implant for each patient. The metaphyseal bone properties affect this decision; however, the typical resection 'thumb test' lacks objectivity. The purposes of this investigation were: to determine the correlation strength between the indentation depth of a handheld mechanism and the density, compressive strength and modulus of a bone surrogate; as well as to assess how changing the indenter tip shape and impact energy may affect the correlation strengths. A spring-loaded indenter was developed. Four tip shapes (needle, tapered, flat and radiused cylinders) and four spring energies (0.13J-0.76J) were assessed by indenting five cellular foam bone surrogates of varying density. The indentation depth was measured and correlated with apparent density, compressive strength and modulus. Indentation depth plateaued as the bone surrogate's material properties increased, particularly for indentation tips with larger footprints and the 0.13J spring. All tip shapes produced strong (R2≥0.7) power-law relationships between the indentation depth metric and the bone surrogate's material properties (density: 0.70 ≤ R2 ≤ 0.95, strength: 0.75 ≤ R2 ≤ 0.97, modulus: 0.70 ≤ R2 ≤ 0.93); though use of the needle tip yielded the widest indentation depth scale. These strong correlations suggest that a handheld indenter may provide objective intraoperative evidence of cancellous material properties. Further investigations are warranted to study indenter tip shape and spring energy in human tissue; though the needle tip with spring energy between 0.30J and 0.76J seems the most promising.

scholarly journals Development of a New Bead Movement-Based Computational Framework Shows that Bacterial Amyloid Curli Reduces Bead Mobility in Biofilms

2020 ◽  
Vol 202 (18) ◽  
Author(s):  
K. Malhotra ◽  
T. Hunter ◽  
B. Henry ◽  
Y. Ishmail ◽  
P. Gaddameedi ◽  
...  
Keyword(s):  
Mathematical Models ◽  
Open Source ◽  
Material Properties ◽  
Laser Scanning ◽  
Cell Movement ◽  
Laser Scanning Confocal Microscopy ◽  
Critical Parameters ◽  
Gastrointestinal Microbiota ◽  
Content Type ◽  
Scanning Confocal Microscopy

ABSTRACT Biofilms exist in complex environments, including the intestinal tract, as a part of the gastrointestinal microbiota. The interaction of planktonic bacteria with biofilms can be influenced by material properties of the biofilm. During previous confocal studies, we observed that amyloid curli-containing Salmonella enterica serotype Typhimurium and Escherichia coli biofilms appeared rigid. In these studies, Enterococcus faecalis, which lacks curli-like protein, showed more fluid movement. To better characterize the material properties of the biofilms, a four-dimensional (4D) model was designed to track the movement of 1-μm glyoxylate beads in 10- to 20-μm-thick biofilms over approximately 20 min using laser-scanning confocal microscopy. Software was developed to analyze the bead trajectories, the amount of time they could be followed (trajectory life span), the velocity of movement, the surface area covered (bounding boxes), and cellular density around each bead. Bead movement was found to be predominantly Brownian motion. Curli-containing biofilms had very little bead movement throughout the low- and high-density regions of the biofilm compared to E. faecalis and isogenic curli mutants. Curli-containing biofilms tended to have more stable bead interactions (longer trajectory life spans) than biofilms lacking curli. In biofilms lacking curli, neither the velocity of bead movement nor the bounding box volume was strictly dependent on cell density, suggesting that other material properties of the biofilms were influencing the movement of the beads and flexibility of the material. Taken together, these studies present a 4D method to analyze bead movement over time in a 3D biofilm and suggest curli confers rigidity to the extracellular matrix of biofilms. IMPORTANCE Mathematical models are necessary to understand how the material composition of biofilms can influence their physical properties. Here, we developed a 4D computational toolchain for the analysis of bead trajectories, which laid the groundwork for establishing critical parameters for mathematical models of particle movement in biofilms. Using this open-source trajectory analyzer, we determined that the presence of bacterial amyloid curli changes the material properties of a biofilm, making the biofilm matrix rigid. This software is a powerful tool to analyze treatment- and environment-induced changes in biofilm structure and cell movement in biofilms. The open-source analyzer is fully adaptable and extendable in a modular fashion using VRL-Studio to further enhance and extend its functions.

scholarly journals Reduction of Dynamic Impacts in Block Made of Concrete - Rubber Composites

2018 ◽  
Vol 14 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Maciej Major ◽  
Izabela Major ◽  
Daniela Kuchárová ◽  
Krzysztof Kuliński
Keyword(s):  
Numerical Analysis ◽  
Dynamic Load ◽  
Material Properties ◽  
Material Model ◽  
Damping Factor ◽  
Rubber Composites ◽  
Elastic Deformations ◽  
Real Material ◽  
Additional Protection ◽  
Rubber Concrete

AbstractThe paper presents numerical analysis of block made of three layers: concrete with I-shape rubber pads, space filled with air and concrete with embedded cross rubber pads, respectively. The block is subjected to the dynamic load. To the analysis as rubber the hyperelastic incompressible Zahorski material model was assumed. This material well describes the real material properties in the range of large elastic deformations. Embedded rubber pads provide an additional protection against the transversal dynamic load. ADINA software was utilized to perform numerical analysis of determining the percentage damping factor of rubber-concrete composite in comparison with block made of concrete.

Grey cast irons for thermal-stress applications

1970 ◽  
Vol 5 (2) ◽  
pp. 98-109 ◽  
Author(s):  
R Bertodo
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Material Properties ◽  
Alternative Assessment ◽  
Flake Graphite ◽  
Cast Irons ◽  
Mechanical And Physical Properties ◽  
The Matrix ◽  
Grey Cast ◽  
Engine Components

Pearlitic flake-graphite grey cast irons have long been widely used for the manufacture of diesel-engine combustion-chamber components. Nonetheless, very few pertinent high-temperature data are to be found in published work. The investigation described attempts to enlarge current knowledge on the high-temperature behaviour of grey cast irons in view of requirements highlighted by high thermal ratings. A general consideration of the problem showed that the often quoted Eichelberg material-quality factor is largely irrelevant and an alternative assessment formula is proposed. This is broadly confirmed by a systematic examination of the mechanical and physical properties of 166 plain and alloyed cast irons and a limited number of engine components. Different engine components impose different demands upon the material properties but for economic reasons a single cast-iron melt capable of meeting most of the requirements of all components is needed. It is shown that this situation is best met with an alloyed iron containing 1.3 per cent of copper-nickel and 0.4 per cent of molybdenum. The scatter in properties obtained from production casts was found to be typical for such irons. For components having safety factors of 2 or less, a prerequisite of economic engineering design, the service reliability is crucially dependent upon the scatter of material properties. Thus, there are advantages in reducing this scatter and it is shown that this can be achieved by attention to the cleanliness of the matrix and tight control of the chemistry of the melt. In general, the absolute values of mechanical and physical properties of flake-graphite cast irons appear to be governed mainly by the form and size of the graphite flakes and the chemistry of the matrix (i.e. CEV and alloying additions). Regression analysis of the results permitted the derivation of empirical formulae for the prediction of the iron properties. The general findings are used to suggest possible ways of improving the thermal resistance.

scholarly journals Attenuation of waves in a viscoelastic peridynamic medium

2019 ◽  
Vol 24 (11) ◽  
pp. 3597-3613 ◽  
Author(s):  
S. A. Silling
Keyword(s):  
Attenuation Coefficient ◽  
Material Properties ◽  
Cutoff Frequency ◽  
Material Model ◽  
One Dimensional ◽  
Spatial Nonlocality ◽  
Dissipative Material ◽  
The Time Domain ◽  
The Relationship ◽  
Theoretical Results

The effect of spatial nonlocality on the decay of waves in a dissipative material is investigated. The propagation and decay of waves in a one-dimensional, viscoelastic peridynamic medium is analyzed. Both the elastic and damping terms in the material model are nonlocal. Waves produced by a source with constant amplitude applied at one end of a semi-infinite bar decay exponentially with distance from the source. The model predicts a cutoff frequency that is influenced by the nonlocal parameters. A method for computing the attenuation coefficient explicitly as a function of material properties and source frequency is presented. The theoretical results are compared with direct numerical simulations in the time domain. The relationship between the attenuation coefficient and the group velocity is derived. It is shown that in the limit of long waves (or small peridynamic horizon), Stokes’ law of sound attenuation is recovered.

Material Properties of Refractory Concrete under High Temperature

2015 ◽  
Vol 1126 ◽  
pp. 155-160
Author(s):  
Stanislav Šťastník ◽  
František Šot ◽  
Jiří Vala
Keyword(s):  
High Temperature ◽  
Solar Radiation ◽  
Physical Properties ◽  
Material Properties ◽  
Refractory Concrete ◽  
Thermal Storage ◽  
Thermal Transfer ◽  
The Core

The paper presents the validation of physical properties of refractory concrete with heavy filling, using the measurements under high temperature, assumed for the construction of a thermal storage. The whole system, consisting of the storage core and of the insulation container, is characterized by non-stationary thermal transfer, supplied from solar radiation into the core. The validation of behaviour of the system (including its sleeping state and the dynamics of charging and discharging) is needed for the optimization of its size parameters.

MODELING OF ALKALI-SILICA REACTION IN A TWO-PHASED MATERIAL MODEL

2015 ◽  
Vol 76 (9) ◽  
Author(s):  
Zarina Itam ◽  
Hazran Husain
Keyword(s):  
Material Properties ◽  
Mesoscale Model ◽  
Damage Model ◽  
Material Model ◽  
Silica Content ◽  
Alkali Silica Reaction ◽  
Complex Phenomenon ◽  
Damage Propagation ◽  
Element Technique ◽  
The Relationship

Alkali-silica reaction causes major problems in concrete structures due to the rapidity of its deformation. Factors that affect ASR include the alkali and silica content, relative humidity, temperature and porosity of the concrete, making the relationship a complex phenomenon to be understood. Hence, the finite element technique was used to build models to study the damage propagation due to ASR. Seeing that ASR initializes in the mesoscopic regions of the concrete, the damage model for ASR at the mesoscale level is studied. The heterogeneity of the mesoscale model shows how difference in material properties between aggregates and the cementitious matrix facilitates ASR expansion. With this model mesoscopic, two-phased material model, the ASR phenomenon under thermo-chemo-hygro-mechanical loading can be understood.

scholarly journals Receptacle interacts with consumers’ need for touch to influence tea-drinking experience

2020 ◽  
Vol 122 (9) ◽  
pp. 2981-2992
Author(s):  
Chujun Wang ◽  
Yubin Peng ◽  
Charles Spence ◽  
Xiaoang Wan
Keyword(s):  
Willingness To Pay ◽  
Physical Properties ◽  
Significant Influence ◽  
Material Properties ◽  
Design Methodology ◽  
Room Temperature ◽  
Haptic Perception ◽  
Content Type ◽  
Ceramic Glass ◽  
Tea Drinking

PurposeThis study was designed to investigate how the material properties of the tea-drinking receptacle interact with a participant's motivation and preference for extracting and using information obtained via haptic perception, namely the need for touch (NFT), to influence his or her tea-drinking experience.Design/methodology/approach72 blindfolded participants were instructed to sample room temperature tea beverages served in a cup that was made of ceramic, glass, paper or plastic. They were then asked to rate how familiar they were with the taste of the beverage, to rate how pleasant the taste was and to specify how much they would like to pay for it (i.e. willingness-to-pay ratings).FindingsThe material of the receptacles used to serve the tea exerted a significant influence over the pleasantness ratings of the tea and interacted with the participants' NFT, exerting a significant influence over their willingness to pay for the tea. Specifically, high-NFT participants were willing to pay significantly more for the same cup of tea when it was served in a ceramic cup rather than in a paper cup, whereas the low-NFT participants' willingness to pay for the tea was unaffected by the material of the receptacles.Originality/valueOur findings suggest that consumers may not be equally susceptible to the influence of the receptacle in which tea, or any other beverage, is served. Our findings also demonstrate how the physical properties of a receptacle interact with a consumer's motivation and preference to influence his or her behavior in the marketplace.

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