Boehmite Nanofiber-Reinforced Resorcinol-Formaldehyde Macroporous Monoliths for Heat/Flame Protection

2018 ◽  
Author(s):  
Gen Hayase
Keyword(s):  
Phase Separation ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Young's Modulus ◽  
Flame Resistance ◽  
Resorcinol Formaldehyde ◽  
Insulating Properties ◽  
Flame Protection

By distributing boehmite nanofibers (BNFs) to a resorcinol-formaldehyde (RF) skeletal phase formed by phase separation in an aqueous sol, composite macroporous monoliths have been produced. The nanofiber reinforced monoliths have a skeleton in which BNF is arranged in parallel within the RF structure, and showed high Young's modulus against uniaxial compression for their bulk density. These materials can be expected to be applied to heat/flame protection materials using heat insulating properties and high flame resistance.<br>

scholarly journals Boehmite Nanofiber-Reinforced Resorcinol-Formaldehyde Macroporous Monoliths for Heat/Flame Protection

2018 ◽  
Author(s):  
Gen Hayase
Keyword(s):  
Phase Separation ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Young's Modulus ◽  
Flame Resistance ◽  
Resorcinol Formaldehyde ◽  
Insulating Properties ◽  
Flame Protection

By distributing boehmite nanofibers (BNFs) to a resorcinol-formaldehyde (RF) skeletal phase formed by phase separation in an aqueous sol, composite macroporous monoliths have been produced. The nanofiber reinforced monoliths have a skeleton in which BNF is arranged in parallel within the RF structure, and showed high Young's modulus against uniaxial compression for their bulk density. These materials can be expected to be applied to heat/flame protection materials using heat insulating properties and high flame resistance.<br>

Simulation of Uniaxial Compression for Flexible Fibers of Wheat Straw Using the Discrete Element Method

2021 ◽  
Vol 64 (6) ◽  
pp. 2025-2034
Author(s):  
Matthew W Schramm ◽  
Mehari Z. Tekeste ◽  
Brian L Steward
Keyword(s):  
Discrete Element Method ◽  
Wheat Straw ◽  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Material Properties ◽  
Young's Modulus ◽  
Discrete Element ◽  
Flexible Fibers ◽  
Dem Model ◽  
Element Method

HighlightsSimulation of uniaxial compression was performed with flexible fibers modeled in DEM.Bond-specific DEM parameters were found to be sensitive in uniaxial compression.A calibration technique that is not plunger-dependent is shown and validated.Abstract. To accurately simulate a discrete element method (DEM) model, the material properties must be calibrated to reproduce bulk material behavior. In this study, a method was developed to calibrate DEM parameters for bulk fibrous materials using uniaxial compression. Wheat straw was cut to 100.2 mm lengths. A 227 mm diameter cylindrical container was loosely filled with the cut straw. The material was pre-compressed to 1 kPa. A plunger (50, 150, or 225 mm diameter) was then lowered onto the compressed straw at a rate of 15 mm s-1. This experimental procedure was simulated using a DEM model for different material properties to generate a simulated design of experiment (DOE). The simulated plunger had a travel rate of 40 mm s-1. The contact Young’s modulus, bond Young’s modulus, and particle-to-particle friction DEM parameters were found to be statistically significant in the prediction of normal forces on the plunger in the uniaxial compression test. The DEM calibration procedure was used to approximate the mean laboratory results of wheat straw compression with root mean square (RMS) percent errors of 3.77%, 3.02%, and 13.90% for the 50, 150, and 225 mm plungers, respectively. Keywords: Calibration, DEM, DOE, Flexible DEM particle, Uniaxial compression, Wheat straw.

Predict Geomechanical Parameters with Machine Learning Combining Drilling Data and Gamma Ray

2021 ◽  
Author(s):  
Mattia Martinelli ◽  
Ivo Colombo ◽  
Eliana Rosa Russo
Keyword(s):  
Machine Learning ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Gamma Ray ◽  
Young's Modulus ◽  
Geomechanical Parameters ◽  
Drilling Parameters ◽  
Unseen Data ◽  
Drilling Data ◽  
Sonic Logs

Abstract The aim of this work is the development of a fast and reliable method for geomechanical parameters evaluation while drilling using surface logging data. Geomechanical parameters are usually evaluated from cores or sonic logs, which are typically expensive and sometimes difficult to obtain. A novel approach is here proposed, where machine learning algorithms are used to calculate the Young's Modulus from drilling parameters and the gamma ray log. The proposed method combines typical mud logging drilling data (ROP, RPM, Torque, Flow measurements, WOB and SPP), XRF data and well log data (Sonic logs, Bulk Density, Gamma Ray) with several machine learning techniques. The models were trained and tested on data coming from three wells drilled in the same basin in Kuwait, in the same geological units but in different reservoirs. Sonic logs and bulk density are used to evaluate the geomechanical parameters (e.g. Young's Modulus) and to train the model. The training phase and the hyperparameter tuning were performed using data coming from a single well. The model was then tested against previously unseen data coming from the other two wells. The trained model is able to predict the Young's modulus in the test wells with a root mean squared error around 12 GPa. The example here provided demonstrates that a model trained with drilling parameters and gamma ray coming from one well is able to predict the Young Modulus of different wells in the same basin. These outcomes highlight the potentiality of this procedure and point out several implications for the reservoir characterization. Indeed, once the model has been trained, it is possible to predict the Young's Modulus in different wells of the same basin using only surface logging data.

An experimental study of mechanical behavior of brittle rock-like specimens with multi-non-persistent joints under uniaxial compression and damage analysis

2019 ◽  
Vol 28 (10) ◽  
pp. 1490-1522 ◽  
Author(s):  
Wendong Yang ◽  
Guizhi Li ◽  
PG Ranjith ◽  
Lindong Fang
Keyword(s):  
Mechanical Behavior ◽  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Joint Angle ◽  
Young's Modulus ◽  
Jointed Rock ◽  
Peak Strength ◽  
Rock Masses ◽  
Jointed Rock Masses ◽  
Joint Length

The mechanical behavior of jointed rock masses significantly affects the stability of rock engineering applications. In this paper, the peak strength, Young's modulus and failure patterns of brittle rock-like specimens with multi-non-persistent joints under uniaxial compression are investigated. The joint geometry is defined by four factors: joint angle, spacing, joint length, and rock bridge length. The experiment results show that the joint angle has the greatest influence on the peak strength and Young's modulus of specimens, followed by joint length. A damage mechanical theory is adopted which deals with some sets of joints distributed in rock masses. Based on the geometrical distribution of joints, a macro damage model which considers the influence of the normal vector and area density of joints is used to describe the joints. The peak strength and Young's modulus of jointed specimens predicted by the damage mechanics method reflect the trend of the experimental results, which proves the influence of initial geometric damage of joints on the peak strength and Young's modulus of jointed specimens. The initial geometric damage of joints is mainly induced by the joint area density. Finally, from the micro damage aspect, to analyze the damage evolution and strain softening process of jointed rock masses, a modified numerical model (damage strainsofting model) on the basis of secondary development in fast Lagrangian analysis of Continua is proposed to simulate the fracture development of jointed rock masses. The peak strengths, Young's modulus and failure modes of rock specimens with non-persistent joints under uniaxial compressions are simulated and compared with the results obtained from the lab experiments indicating that the model is capable to replicate the physical processes.

scholarly journals The Effect of Cerium Oxide Addition on the Properties and Behavior of Y-TZP

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
D. Ragurajan ◽  
M. Satgunam ◽  
M. Golieskardi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Sintering Behavior ◽  
Optimum Level ◽  
Oxide Addition ◽  
Time Cycle ◽  
And Behavior

The effects of CeO2 addition on the sintering behavior and mechanical properties of Y-TZP have been investigated over a wide sintering regime by pressureless sintering. It has been revealed that small additions of CeO2 (0.3–1.0 wt%) to Y-TZP were beneficial in enhancing the mechanical properties and hydrothermal ageing resistance of Y-TZP. Sintered samples were used to evaluate the bulk density, Vickers’s hardness, Young’s modulus, and fracture toughness of the material. CeO2 doped Y-TZPs were sintered at relatively low temperatures (1250°C and 1350°C) retaining high bulk density (>97% of theoretical density) and high Young’s modulus (>200 GPa) without sacrificing tetragonal phase stability. The optimum level of dopant was found to be at 0.5 wt% for sintering between 1250°C and 1450°C using the standard 2 h holding time cycle, with sintered body exhibiting excellent combination of properties when compared to the undoped ceramics. In this experiment, the addition of 0.5 wt% recorded a bulk density reading of 5.9 g/cm3, Vickers hardness value of 13.2 GPa, Young’s modulus value of 211 GPa, and fracture toughness of 6.4 MPam1/2, respectively, in a temperature range of 1400–1450°C.

Densification Behavior of Nano Y-TZP Ceramics

2013 ◽  
Vol 372 ◽  
pp. 165-168 ◽  
Author(s):  
A. Norakmal ◽  
Ramesh Singh ◽  
C.Y. Tan ◽  
W.D. Teng
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Sintering Temperature ◽  
Young's Modulus ◽  
Densification Behavior ◽  
Work Samples ◽  
Hardness Values

The effects of sintering temperatures on consolidation and mechanical properties of 3 mol% Y-TZP (3Y-TZP) powders were studied in this work. Samples were sintered at 1250°C to 1450°C sintering temperature in air. Throughout the sintering regime, high value of relative bulk density 99.41% of theoretical densities was obtained for the maximum sintering temperature. Maximum Young's modulus of 3Y-TZP was obtained at 1450°C and maximum fracture toughness value of 3Y-TZP was observed at the 1300°C sintering temperature. The Vickers's hardness values of 3Y-TZP also increased gradually with sintering temperature.

scholarly journals Highly Porous 3D Printed Tantalum Scaffolds Have Better Biomechanical and Microstructural Properties than Titanium Scaffolds

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Huaquan Fan ◽  
Shu Deng ◽  
Wentao Tang ◽  
Aikeremujiang Muheremu ◽  
Xianzhe Wu ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Young's Modulus ◽  
Equivalent Stress ◽  
Biomechanical Properties ◽  
Porous Scaffolds ◽  
Compression Tests ◽  
Bone Scaffolds ◽  
Melting Technique ◽  
3D Printed

Objective. To test the biomechanical properties of 3D printed tantalum and titanium porous scaffolds. Methods. Four types of tantalum and titanium scaffolds with four alternative pore diameters, #1 (1000-700 μm), #2 (700-1000 μm), #3 (500-800 μm), and #4 (800-500 μm), were molded by selective laser melting technique, and the scaffolds were tested by scanning electronic microscope, uniaxial-compression tests, and Young’s modulus tests; they were compared with same size pig femoral bone scaffolds. Results. Under uniaxial-compression tests, equivalent stress of tantalum scaffold was 411 ± 1.43  MPa, which was significantly larger than the titanium scaffolds ( P < 0.05 ). Young’s modulus of tantalum scaffold was 2.61 ± 0.02  GPa, which was only half of that of titanium scaffold. The stress-strain curves of tantalum scaffolds were more similar to pig bone scaffolds than titanium scaffolds. Conclusion. 3D printed tantalum scaffolds with varying pore diameters are more similar to actual bone scaffolds compared with titanium scaffolds in biomechanical properties.

scholarly journals The Relationship between the Visco-Elastic and Structural Properties of Fine-Grained Snow

1975 ◽  
Vol 14 (72) ◽  
pp. 479-500 ◽  
Author(s):  
P. R. Kry
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Uniaxial Compression ◽  
Young's Modulus ◽  
Creep Behaviour ◽  
Fold Increase ◽  
Snow Sample ◽  
Mean Values ◽  
Fine Grained ◽  
Grain Properties

New and felt-like snow was sieved and sintered at a constant temperature in order to produce homogeneous samples of fine, rounded-grain snow with a density in the range 270–340 kg m−3. The structure of single samples was changed in stages by non-destructive uniaxial compression. This deformation, which amounted to 30%, took place within 8 hours (thus limiting temperature metamorphism). At each stage the Young’s modulus was measured quasi-statically and the creep behaviour under constant uniaxial compression was recorded. Stereological analysis of sections from the samples provided mean values for both grain-bond and grain properties. The Young’s modulus increased with density slightly more strongly than linearly, whereas the low-stress viscosity in unconfined compression increased nearly exponentially for densities less than 380 kg m−3. The maximum densification resulted in a 15-fold increase in the measured visco-elastic properties. However, the number of grain bonds per unit mass increased linearly by a factor in the range 1.5 to 2 while the average grain-bond size remained constant. It is concluded that only a fraction of the grain bonds in a snow sample transmit an applied stress, and that the new grain bonds formed during the deformation of a snow sample determine the visco-elastic properties of snow. The hypothesis that chains, defined as series of stress-bearing grains, are the basic units of snow structure is developed. Semi-quantitative calculations developed from the chain concept explain the observed variations in the visco-elastic properties.

scholarly journals The Relationship between the Visco-Elastic and Structural Properties of Fine-Grained Snow

1975 ◽  
Vol 14 (72) ◽  
pp. 479-500 ◽  
Author(s):  
P. R. Kry
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Uniaxial Compression ◽  
Young's Modulus ◽  
Creep Behaviour ◽  
Fold Increase ◽  
Snow Sample ◽  
Mean Values ◽  
Fine Grained ◽  
Grain Properties

New and felt-like snow was sieved and sintered at a constant temperature in order to produce homogeneous samples of fine, rounded-grain snow with a density in the range 270–340 kg m−3. The structure of single samples was changed in stages by non-destructive uniaxial compression. This deformation, which amounted to 30%, took place within 8 hours (thus limiting temperature metamorphism). At each stage the Young’s modulus was measured quasi-statically and the creep behaviour under constant uniaxial compression was recorded. Stereological analysis of sections from the samples provided mean values for both grain-bond and grain properties. The Young’s modulus increased with density slightly more strongly than linearly, whereas the low-stress viscosity in unconfined compression increased nearly exponentially for densities less than 380 kg m−3. The maximum densification resulted in a 15-fold increase in the measured visco-elastic properties. However, the number of grain bonds per unit mass increased linearly by a factor in the range 1.5 to 2 while the average grain-bond size remained constant. It is concluded that only a fraction of the grain bonds in a snow sample transmit an applied stress, and that the new grain bonds formed during the deformation of a snow sample determine the visco-elastic properties of snow. The hypothesis that chains, defined as series of stress-bearing grains, are the basic units of snow structure is developed. Semi-quantitative calculations developed from the chain concept explain the observed variations in the visco-elastic properties.

scholarly journals The Influence of Fly Ash on Mechanical Properties of Clay-Based Ceramics

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 930
Author(s):  
Tomáš Húlan ◽  
Igor Štubňa ◽  
Ján Ondruška ◽  
Anton Trník
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Room Temperature ◽  
Young's Modulus ◽  
Thermal Power ◽  
Thermomechanical Analysis ◽  
Bending Test ◽  
Lower Amount

Elastic properties of mixtures of illitic clay, thermal power plant fly ash (fluidized fly ash—FFA and pulverized fly ash—PFA), and grog were investigated during the heating and cooling stages of the firing. The grog part in the mixtures was replaced with 10, 20, 30, and 40 mass% of the fly ash, respectively. The temperature dependence of Young’s modulus was derived using the dynamical thermomechanical analysis, in which dimensions and mass determined from thermogravimeric and thermodilatometric results were used. Flexural strength was measured at the room temperature using the three-point bending test. The following results were obtained: (1) Bulk density showed a decreasing trend up to 900 °C and a steep increase above 900 °C. During cooling, the bulk density slightly increased down to the room temperature. (2) Young’s modulus increased significantly during heating up to ~300 °C. Dehydroxylation was almost not reflected in Young’s modulus. At temperatures higher than 800 °C, Young’s modulus began to increase due to sintering. (3) During cooling, down to the glass transformation, Young’s modulus slightly increased and then began to slightly decrease due to microcracking between phases with different thermal expansion coefficients. (4) Around the β→α quartz transition, radial stresses on the quartz grain altered from compressive to tensile, creating microcracks. Below 560 °C, the radial stress remained tensile, and consequently, the microcracking around the quartz grains and a decreasing Young’s modulus continued. (5) With a lower amount of PFA and FFA, a higher Young’s modulus was reached after sintering. The final values of Young’s modulus, measured after firing, show a decreasing trend and depend linearly on the part of fly ash. (6) The flexural strength measured after firing decreased linearly with the amount of the fly ash for both mixtures.

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