scholarly journals A model of digestive tooth corrosion in lizards: experimental tests and taphonomic implications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Krister T. Smith ◽  
Orr Comay ◽  
Lutz Maul ◽  
Fabio Wegmüller ◽  
Jean-Marie Le Tensorer ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Experimental Tests ◽  
Model System ◽  
Experimental Results ◽  
Deep Time ◽  
Feeding Experiments ◽  
Enzyme Systems ◽  
High Enzyme ◽  
Gastric Fluids ◽  
Owl Pellets

AbstractCorrosion patterns induced by gastric fluids on the skeleton of prey animals may depend on the nature of the corrosive agents (acid, enzymes) as well as on the composition of the hard parts and the soft tissues that surround them. We propose a framework for predicting and interpreting corrosion patterns on lizard teeth, our model system, drawing on the different digestive pathways of avian and non-avian vertebrate predators. We propose that high-acid, low-enzyme systems (embodied by mammalian carnivores) will lead to corrosion of the tooth crowns, whereas low-acid, high-enzyme systems (embodied by owls) will lead to corrosion of the tooth shafts. We test our model experimentally using artificial gastric fluids (with HCl and pepsin) and feeding experiments, and phenomenologically using wild-collected owl pellets with lizard remains. Finding an association between the predictions and the experimental results, we then examine corrosion patterns on nearly 900 fossil lizard jaws. Given an appropriate phylogenetic background, our focus on physiological rather than taxonomic classes of predators allows the extension of the approach into Deep Time.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

Atomistic insights into the structure and elasticity of densified 45S5 bioactive glasses

2021 ◽  
Author(s):  
Youssef Ouldhnini ◽  
Achraf Atila ◽  
Said Ouaskit ◽  
abdellatif hasnaoui
Keyword(s):  
Regenerative Medicine ◽  
Soft Tissues ◽  
Soda Lime ◽  
Model System ◽  
Bioactive Glasses

Glasses have applications in regenerative medicine due to their bioactivity, enabling interactions with hard and soft tissues. Soda-lime phosphosilicate glasses, such as 45S5, represent a model system of bioactive glasses....

scholarly journals Numerical and experimental evaluation of masonry prisms by finite element method

2017 ◽  
Vol 10 (2) ◽  
pp. 477-508 ◽  
Author(s):  
C. F.R. SANTOS ◽  
R. C. S. S. ALVARENGA ◽  
J. C. L. RIBEIRO ◽  
L. O CASTRO ◽  
R. M. SILVA ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
High Strength Concrete ◽  
Numerical Models ◽  
High Strength ◽  
Experimental Tests ◽  
Experimental Results ◽  
Concrete Blocks ◽  
Micro Modeling ◽  
Modeling Strategy

Abstract This work developed experimental tests and numerical models able to represent the mechanical behavior of prisms made of ordinary and high strength concrete blocks. Experimental tests of prisms were performed and a detailed micro-modeling strategy was adopted for numerical analysis. In this modeling technique, each material (block and mortar) was represented by its own mechanical properties. The validation of numerical models was based on experimental results. It was found that the obtained numerical values of compressive strength and modulus of elasticity differ by 5% from the experimentally observed values. Moreover, mechanisms responsible for the rupture of the prisms were evaluated and compared to the behaviors observed in the tests and those described in the literature. Through experimental results it is possible to conclude that the numerical models have been able to represent both the mechanical properties and the mechanisms responsible for failure.

Experimental Investigation of Flowrate Irregularity in Rotary Gear Pumps

1992 ◽  
Author(s):  
G. Mimmi
Keyword(s):  
Experimental Investigation ◽  
Flow Rate ◽  
Experimental Tests ◽  
Periodic Variation ◽  
Experimental Results ◽  
Gear Pump ◽  
Gear Pumps ◽  
Hot Film ◽  
Instantaneous Flow Rate ◽  
External Gear Pump

Abstract In a previous paper the author proposed a method to reduce the periodic variation in flow rate for an external gear pump. To verify the experimental results, a series of experimental tests on a expressly realized gear pump, was carried out. The pump was equipped with relieving grooves milled into the side plates. The tests were done on a closed piping specifically realized and equipped for measuring the instantaneous flow rate of the fluid through a wedge-shaped hot film probe.

scholarly journals Experimental Results from Laboratory Tests on an 8 Metre Beam Manufactured from Hybrid Composite Fromwork

1998 ◽  
Vol 7 (6) ◽  
pp. 096369359800700 ◽  
Author(s):  
E. Gutiérrez ◽  
G. Di Salvo ◽  
J.M. Mieres ◽  
L. Mogensen ◽  
E. Shahidi ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Hybrid Composite ◽  
High Strength Concrete ◽  
Laboratory Tests ◽  
High Strength ◽  
Experimental Tests ◽  
Experimental Results ◽  
Glass Carbon ◽  
Concrete Elements

In this paper we outline the development of an all-in-one composite reinforcing formwork system for manufacturing reinforced concrete elements, in particular, we describe the main experimental tests carried out on an 8 metre beam using high strength concrete poured and bonded on a hybrid, glass/carbon fibre formwork.

scholarly journals Lighting Control Including Daylight and Energy Efficiency Improvements Analysis

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2166 ◽  
Author(s):  
Aniela Kaminska ◽  
Andrzej Ożadowicz
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Savings ◽  
Residential Buildings ◽  
Experimental Tests ◽  
Experimental Results ◽  
Automation System ◽  
Building Automation ◽  
Total Energy Consumption ◽  
Lighting Control

Energy used for lighting is one of the major components of total energy consumption in buildings. Nowadays, buildings have a great potential to reduce their energy consumption, but to achieve this purpose additional efforts are indispensable. In this study, the need for energy savings evaluation before the implementation of lighting control algorithms for a specified building is highlighted. Therefore, experimental tests have been carried out in a university building with laboratories and other rooms, equipped with KNX building automation system. A dimmable control strategy has been investigated, dependent on daylight illuminance. Moreover, a relationship between external and internal daylight illuminance levels has been evaluated as well. Based on the experimental results, the authors proposed a method for the rough estimation of electrical energy savings. Since, according to the EN 15232 standard, Building Automation and Control Systems (BACS) play an important role in buildings’ energy efficiency improvements, the BACS efficiency factors from this standard have been used to verify the experimental results presented in the paper. The potential to reduce energy consumption from lighting in non-residential buildings by 28% for offices and 24% for educational buildings has been confirmed, but its dependence on specific building parameters has been discussed as well.

Experimental and Measurement Uncertainty Associated With Characterizing Slurry Mixing Performance of Pulsating Jets at Multiple Scales

2015 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Greg F. Piepel ◽  
Carl W. Enderlin ◽  
Brett G. Amidan ◽  
Alejandro Heredia-Langner
Keyword(s):  
Measurement Uncertainty ◽  
Multiple Scales ◽  
Experimental Tests ◽  
Experimental Results ◽  
Cloud Height ◽  
Solids Concentration ◽  
Relative Standard ◽  
Measurement Uncertainties ◽  
Standard Deviations ◽  
Pulsating Jets

Understanding how uncertainty manifests itself in complex experiments is important for developing the testing protocol and interpreting the experimental results. This paper describes experimental and measurement uncertainties, and how they can depend on the order of performing experimental tests. Experiments with pulse-jet mixers in tanks at three scales were conducted to characterize the performance of transient-developing periodic flows in Newtonian slurries. Other test parameters included the simulant, solids concentration, and nozzle exit velocity. Critical suspension velocity and cloud height were the metrics used to characterize Newtonian slurry flow associated with mobilization and mixing. During testing, near-replicate and near-repeat tests were conducted. The experimental results were used to quantify the combined experimental and measurement uncertainties using standard deviations and percent relative standard deviations (%RSD) The uncertainties in critical suspension velocity and cloud height tend to increase with the values of these responses. Hence, the %RSD values are the more appropriate summary measure of near-replicate testing and measurement uncertainty.

A Microscale Collagen-Fibrin Interacting Network Model With Comparison to Experimental Results

2012 ◽  
Author(s):  
Jeffrey D. Hyypio ◽  
Mohammad F. Hadi ◽  
Victor K. Lai ◽  
Victor H. Barocas
Keyword(s):  
Mechanical Loading ◽  
Network Model ◽  
Computer Model ◽  
Soft Tissues ◽  
Uniaxial Extension ◽  
Tissue Mechanics ◽  
Experimental Results ◽  
Large Strains ◽  
Heterogeneous Nature ◽  
Engineered Tissue

Many native and bioengineered soft tissues are composed of two or more types of biopolymer networks that mechanically define and support the material [1]. Modeling the response of multi-network soft tissues to mechanical loading can be difficult due to the heterogeneous nature of these materials and the large strains (>1) involved. As tissues deform, the different biopolymer networks interact with one another and determine the overall stress-strain outcome for the tissue. Capturing this interaction could help improve the accuracy of a computer model to simulate the microscale behavior of soft tissues under load. We have developed a two-network model to reflect interactions between collagen and fibrin biopolymer networks loaded in uniaxial extension. The model can help improve our understanding of native and engineered tissue mechanics.

Computer Aided Finite Element Simulation of the Developed Driller System for Bone Drilling Process in Orthopedic Surgery

2019 ◽  
Vol 18 (04) ◽  
pp. 583-594 ◽  
Author(s):  
Kadir Gok ◽  
Arif Gok ◽  
Yasin Kisioglu
Keyword(s):  
Finite Element ◽  
Temperature Rise ◽  
Orthopedic Surgery ◽  
Soft Tissues ◽  
Experimental Results ◽  
Drilling Process ◽  
Drill Bit ◽  
Bone Drilling ◽  
Computer Aided ◽  
Driller System

Heat reveals during the bone drilling operations in orthopedic surgery because of friction between bone and surgical drill bit. The heating causes extremely important damages in bone and soft tissues. The heating has a critical threshold and it is known as 47∘C. If bone temperature value exceeds 47∘C, osteonecrosis occurs in bones and soft tissues. Many factors such as surgical drill bit geometry and material, drilling parameters, coolant has important roles for the temperature rise. Many methods are used to decrease the temperature rise. The most effective method among them is to use the coolant internally. Numeric simulations of a new driller system to avoid the overheating during the orthopedic operating processes were performed in this study. The numerical simulation with/without coolant was also performed using the finite element based software. Computer aided simulation studies were used to measure the bone temperatures occurred during the bone drilling processes. The outcomes from the simulations were compared with the experimental results. A good temperature level agreement between the experimental results and FEA simulations was found during the bone drilling process.

Experimental and empirical study of large transverse deformation of triangular plates subjected to water hammer shock loading

2019 ◽  
Vol 233 (12) ◽  
pp. 2498-2509
Author(s):  
Mojtaba Haghgoo ◽  
Mohammad Rezasefat ◽  
Ali Mahmoudi ◽  
Hashem Babaei
Keyword(s):  
Mechanical Properties ◽  
Center Of Mass ◽  
Experimental Tests ◽  
Experimental Results ◽  
Dimensionless Numbers ◽  
Hydrodynamic Loads ◽  
Drop Hammer ◽  
Properties Of Materials ◽  
Plate Geometry ◽  
Insight Into

In this paper, the dynamic plastic response of isosceles triangular plates under hydrodynamic loads was investigated experimentally using a drop hammer machine. To do this, a series of experimental tests were carried out on mild steel triangular plates with different thicknesses to bring insight into the effect of geometry and mechanical properties of the plate on the deformation of specimens, which were impacted by a piston-induced pressure wave inside a water tube. The effects of various impact loads originated from different drop hammer standoff distances, and hammer weights concerning variations of deflection of the center of mass were described. The experimental results were presented in terms of deflection of the center of mass of the plates and deflection profiles. The experimental results showed that the plate with lower thickness experienced higher deflection-to-thickness ratio. An empirical model was also proposed based on new dimensionless numbers for triangular plates in order to predict the ratio of deflection of the center of mass to thickness. The dimensionless numbers considered the effects of plate geometry, hydrodynamic applied load, and mechanical properties of materials. Comparison between the experimental results and empirical predictions demonstrated that the suggested model is accurate enough to predict of the response of isosceles triangular plates under hydrodynamic loads.

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