scholarly journals Influence of temperature on physical and mechanical properties of a sedimentary rock: Coal measure mudstone

2019 ◽  
pp. 297-297
Author(s):  
Yuan Zhang ◽  
Zhijun Wan ◽  
John McLennan ◽  
Bin Gu ◽  
TA Xupeng
Keyword(s):  
Mechanical Properties ◽  
Clay Minerals ◽  
Color Change ◽  
Physical And Mechanical Properties ◽  
Phase Changes ◽  
Coal Measure ◽  
Water Evaporation ◽  
X Rays ◽  
Color Changes ◽  
Deep Rock

Determining the physical and mechanical behavior of sedimentary rocks is one of the most common challenges in deep rock mass engineering. Experiments were conducted to study the physical and mechanical properties of coal measure mudstone with scanning electron microscope, x-rays diffraction and uniaxial compression testing. The results show that temperature has a significant effect on the physical and mechanical properties of coal measure mudstone. The presence of clay minerals in the evaluated mudstone contributes to the unique characteristics seen at high temperature. The mudstone experiences obvious color changes on the surface as temperature rises. This is mostly attributed to the iron-bearing clay minerals. Internal color change is caused by thermal decomposition of kerogen associated with the clay minerals. As the major clay mineral in mudstone, kaolinite undergoes significant phase changes at high temperatures, which leads to changes in mechanical properties. From 25? to 200 ?, due to the evaporation of absorbed water from the clay minerals, the strength of the mudstone increases significantly. As the temperature continues to rise beyond this, water evaporation continues and the rock strength increases gradually from 200? to 400 ?. When the temperature reaches 400 ?, this mudstone was strengthened as a result of decomposition of the kaolinite and thermal expansion of crystalline minerals. Above 600?, dehydration of the clay minerals ends while thermal cracking initiates gradually, which results in decreasing strength.

Investigating the effect of the aging process on LDPE composites with UV protective additives

2020 ◽  
pp. 089270572094190
Author(s):  
Sabih Ovalı ◽  
Erhan Sancak
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Color Change ◽  
Accelerated Aging ◽  
Physical And Mechanical Properties ◽  
Ultraviolet Rays ◽  
Color Changes ◽  
Matrix Production ◽  
Ldpe Composites ◽  
Harmful Effects

The contact with ultraviolet rays coming from sunlight causes color changes and deterioration in the main chain structures of composites in outdoor applications and affects the physical and mechanical properties of composite materials negatively. Photodegradation can be slowed and the mechanical strength of composite structures can be improved with adding photostabilizers in polymer matrix production. In this study, we modified low-density polyethylene (LDPE) polymer with an amine light stabilizer (Chimassorb 944), a light absorbent (Tinuvin 326), and an antioxidant (Irganox 1010) and then reinforced with jute fabric (JF). We examined the effect of protective additives, which are used to reduce the harmful effects of sunlight, on JF-reinforced LDPE composites. The color change, physical, and mechanical properties of the composites were determined after 120- and 240-h accelerated aging processes. The results indicate that both the antioxidants and the amine light stabilizers were more effective photostabilizers for JF-reinforced LDPE composites than the absorbents.

Prediction of physical and mechanical properties of thermally modified wood based on color change evaluated by means of “group method of data handling” (GMDH) neural network

Holzforschung ◽  
2019 ◽  
Vol 73 (4) ◽  
pp. 381-392 ◽  
Author(s):  
Vahid Nasir ◽  
Sepideh Nourian ◽  
Stavros Avramidis ◽  
Julie Cool
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Color Change ◽  
Physical And Mechanical Properties ◽  
Group Method ◽  
Data Handling ◽  
Color Parameters ◽  
Swelling Coefficient ◽  
Thermally Modified Wood ◽  
Modified Wood

AbstractThe effect of thermal modification (TM) on the color of western hemlock wood and its physical and mechanical properties were investigated. The focus of this study was the prediction of material properties of thermally modified wood based on the color change via the “group method of data handling (GMDH)” neural network (NN). The NN was trained by color parameters for predicting the equilibrium moisture content (EMC), density, porosity, water absorption (WA), swelling coefficient, dynamic modulus of elasticity (MOEdyn) and hardness. The color parameters showed a significant correlation with temperature and are well correlated with the heat treatment (HT) intensity. Color parameters combined with the GMDH-type NN successfully predicted the physical properties of the material. The best correlation was achieved with the swelling coefficient, EMC and WA. All these properties were significantly influenced by HT. The color parameters did not seem suitable for predicting the wood hardness and MOEdyn. The GMDH NN shows a higher model accuracy than the multivariate linear and partial least squares (PLS) regression models.

scholarly journals Polyolefin/ZnO Composites Prepared by Melt Processing

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2432
Author(s):  
Alojz Anžlovar ◽  
Mateja Primožič ◽  
Iztok Švab ◽  
Maja Leitgeb ◽  
Željko Knez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Antibacterial Activity ◽  
Color Change ◽  
Antibacterial Properties ◽  
Melt Processing ◽  
Degree Of Crystallinity ◽  
Mechanical And Thermal Properties ◽  
Nano Zno ◽  
Color Changes ◽  
Zno Powders

Composites of polyolefin matrices (HDPE and PP) were prepared by melt processing using two commercially available nano ZnO powders (Zinkoxyd aktiv and Zano 20). The mechanical and thermal properties, UV-Vis stability, and antibacterial activity of composites were studied. Tensile testing revealed that both nano ZnO types have no particular effect on the mechanical properties of HDPE composites, while some positive trends are observed for the PP-based composites, but only when Zano 20 was used as a nanofiller. Minimal changes in mechanical properties of composites are supported by an almost unaffected degree of crystallinity of polymer matrix. All polyolefin/ZnO composites exposed to artificial sunlight for 8–10 weeks show more pronounced color change than pure matrices. This effect is more evident for the HDPE than for the PP based composites. Color change also depends on the ZnO concentration and type; composites with Zano 20 show more intense color changes than those prepared with Zinkoxyd aktiv. Results of the antibacterial properties study show very high activity of polyolefin/ZnO composites against Staphylococcus aureus regardless of the ZnO surface modification, while antibacterial activity against Escherichia coli shows only the composites prepared with unmodified ZnO. This phenomenon is explained by different membrane structure of gram-positive (S. aureus) and gram-negative (E. coli) bacteria.

scholarly journals Features of ultrasonic control of mechanical properties of core rocks of geological exploration wells

2019 ◽  
Vol 109 ◽  
pp. 00115
Author(s):  
Anatolii Yalanskyi
Keyword(s):  
Mechanical Properties ◽  
Point Contact ◽  
Physical And Mechanical Properties ◽  
Longitudinal Shear ◽  
Geological Exploration ◽  
Actual Structure ◽  
Deep Wells ◽  
Deep Rock ◽  
Operative Control ◽  
Core Storage

The article discusses the features of ultrasonic operative control of the mechanical properties of rocks of geological exploration wells. The control develops in three directions: ultrasonic logging of exploration wells, the determination of the strength and elastic properties of rocks, taking into account their geological homogeneity; comprehensive monitoring of physical and mechanical properties of cores of deep and ultra-deep wells directly on the wells or core storage facilities. To control samples with untreated ends, it was proposed to use methods and means to ensure the point contact of the sensor with the surface, which allows to accurately determine the distance traveled by the waves through the sample, and taking into account the directional patterns of ultrasonic vibrations to determine the type and speed of the wave. According to the velocities of the longitudinal, shear or surface waves and the density of rocks determine the dynamic elastic parameters. The discrepancy between the actual structure of deep rock massif and seismic data is considered. With depth, the metamorphism of rocks increases. At the considered depths, the crust of rocks has a layered structure, which is due to the alternation of igneous and sedimentary rocks differing in the degree of metamorphism.

Adverse Engineering Properties of Banxi Group Slatealong Changsha Metro Line 2

2012 ◽  
Vol 204-208 ◽  
pp. 1401-1404
Author(s):  
Chen An
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Rock Mass ◽  
Clay Minerals ◽  
Mineral Composition ◽  
Physical And Mechanical Properties ◽  
Engineering Properties ◽  
Test Results ◽  
Softening Coefficient ◽  
Comprehensive Study

For comprehensive study the adverse engineering properties of Banxi Group slate along Changsha Metro Line 2, slate samples were tested and analyzed to research their mineral composition, physical and mechanical properties, weathered properties and disintegration. Test results show that sandy slate and argillite interbedded with each other, the main minerals of slate are quartz and clay minerals, the oxide are SiO2、Al2O3, the natural compressive strength of sandy slate is five to eight times that of argillite, its softening coefficient is less than 0.75, slate is easy to soften, argillite is easy to disintegration and the disintegration of sandy slate is medium grade. The adverse engineering characteristics lead to slate rock mass uneven with hard-soft. Differential weather of slate causes there are some bedrock weathered slots along Changsha Metro Line 2. So during construction, appropriate process and tool must be selected, control the tunnel oriented, strengthen the protection and shorten the bare time of rock mass.

Color Stability of Glass Ionomer Cement (GIC) Modified with Silica from Beach Sand after Immersion in Arabica Gayo Coffee

2020 ◽  
Vol 48 ◽  
pp. 99-104
Author(s):  
Liana Rahmayani ◽  
Iin Sundari ◽  
Diana Setya Ningsih ◽  
Pocut Aya Sofya ◽  
Rabithah Nasution
Keyword(s):  
Mechanical Properties ◽  
Color Change ◽  
Glass Ionomer Cement ◽  
Color Stability ◽  
Beach Sand ◽  
Glass Ionomer ◽  
Intrinsic Factors ◽  
Average Value ◽  
Color Changes ◽  
Ionomer Cement

The discoloration is a condition that can affect the color stability of a material. The discoloration of glass ionomer cement (GIC) can occur due to extrinsic and intrinsic factors. GIC has poor mechanical properties, which are brittle, which shows high microporosity in GIC. Microporosity of GIC can affect the ability of materials in maintaining color stability. Therefore, it is necessary to add material alternatives to improve the mechanical properties in order to maintain color stability in GIC, such as silica. This study aims to determine the color change in GIC which is added with 5% silica after immersion in gayo arabica packaging coffee. Cylindrical specimens with a diameter of 5 mm and 2 mm thick. Specimens amounted to 16 pieces consisting of two treatment groups, the first group using conventional GIC and the second group using GIC with the addition of silica. Both groups were immersed in arabica gayo coffee for 4 days. Color changes were observed with a stereomicroscope and then the value of CIELab was used using Adobe Photoshop, which measured its average color change parameter (ΔE). The average value of discoloration of conventional GIC ΔE = 5.77 and GIC with the silica addition ΔE = 7.94. The results of the unpaired t-test show a value (p> 0.05) which means that there is a significant color change. It can be concluded that the two groups had discoloration after immersion in Arabica gayo coffee, and the color change value in conventional GIC with the addition of silica was higher than conventional GIC.

scholarly journals Color stability of an artificially aged nanofilled composite resin post-cured with different techniques

2021 ◽  
Vol 15 (1) ◽  
pp. 53-58
Author(s):  
Lais Sampaio Souza ◽  
Tais Rocha Donato ◽  
Gabriela Alves Cerqueira ◽  
Andrea Nobrega Cavalcanti ◽  
Paula Mathias
Keyword(s):  
Composite Resin ◽  
Color Change ◽  
Physical And Mechanical Properties ◽  
Color Stability ◽  
Microwave Oven ◽  
Composite Resins ◽  
Distilled Water ◽  
Color Analysis ◽  
Color Changes ◽  
Total Color Change

Background. Post-cured composite resins exhibit improvements in physical and mechanical properties due to additional polymerization conversion. However, the post-curing techniques might influence the color stability of composite resin materials. Thus, this study evaluated the color stability of a nanofilled composite resin (Filtek Z350 XT - 3M ESPE) subjected to different post-curing techniques. Methods. Sixty samples (color A2) were randomly allocated to six experimental groups (n=10): G1: photoactivation (P) (control); G2: P + microwave oven with distilled water; G3: P + microwave oven without distilled water; G4: P + conventional oven; G5: P + dry-heat sterilizer; G6: P + steam autoclave. All the groups were stored in distilled water for 60 days and immersed daily in 5 mL of a coffee solution for 3 minutes. The color readings (CIEL*a*b* system) were performed at two different time intervals, initially and after 60 days, in a reflectance spectrophotometer (UV-2600; Shimadzu). The colorimetric readings were performed using the Color Analysis software (CIEL*a*b* system). Results. Group G6 exhibited significantly low values of total color change (ΔE=13.16). The control (ΔE=15.32) and G5 (ΔE=15.49) groups exhibited intermediate values, with no difference between them. In turn, the groups in which the resin was heated in a microwave (G2 ΔE=18.55 and G3 ΔE=19.45) exhibited the most significant color changes (one-way ANOVA and Tukey test, P≤0.05). Conclusion. Steam autoclave post-polymerization increased the color stability of the nanofilled resin subjected to artificial aging and coffee immersion.

PEMANFAATAN KAYU AKASIA MANGIUM (Acacia mangium Willd) UNTUK MEBEL

2012 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Djoko Purwanto
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physical Properties ◽  
Treatment Process ◽  
Acacia Mangium ◽  
Physical And Mechanical Properties ◽  
Wood Fibers ◽  
Test Parameters ◽  
Mechanical And Physical Properties ◽  
Scale Scores

Timber Acacia mangium (Acacia mangium, Willd) for Furniture. The study aims to determine the mechanical and physical properties and the decorative value (color and fiber) wood of acacia mangium with using finishing materials. This type of finishing material used is ultran lasur natural dof ,ultran lasur classic teak, aqua politur clear dof, aqua politur akasia dan aqua politur cherry. After finishing the wood is stored for 3 months. Test parameters were observed, namely, physical and mechanical properties of wood, adhesion of finishing materials, color and appearance of the fiber, and timber dimensions expansion. The results showed that the mechanical physical properties of acacia wood qualified SNI. 01-0608-89 about the physical and mechanical properties of wood for furniture, air dry the moisture content from 13.78 to 14.89%, flexural strength from 509.25 to 680.50 kg/cm2, and compressive strength parallel to fiber 342.1 - 412.9 kg/cm2. Finishing the treatment process using five types of finishing materials can increase the decorative value (color and fiber) wood. Before finishing the process of acacia mangium wood has the appearance of colors and fibers and less attractive (scale scores 2-3), after finishing acacia wood fibers have the appearance of colors and interesting and very interesting (scale 4-5).Keywords: mangium wood, mechanical properties, decorative value, finishing, furniture.

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