scholarly journals Hydroxypropyl cellulose loaded with ZnO nanoparticles for enhancing the mechanical properties of papyrus (Cyperus papyrus L.) strips

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2607-2625
Author(s):  
Rushdya Rabee Ali Hassan ◽  
Salwa Moustafa Amer Mahmoud ◽  
Marina Atef Nessem ◽  
Reham Tarek Abdel Aty ◽  
Mariam George Ramzy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Zno Nanoparticles ◽  
Color Change ◽  
Crystallinity Index ◽  
Visual Assessment ◽  
Artificial Ageing ◽  
Universal Serial Bus ◽  
Before And After ◽  
Digital Microscope ◽  
The Impact

Unfortunately, papyrus has not been sufficiently studied regarding improvement of the mechanical or optical properties, which degrade under the impact of aging factors over time. The aims of this research were studying the effects of hydroxypropylcellulose (HPC) loaded with 0.25% of ZnO nanoparticles (NP) at different concentrations (1% and 2%) on papyrus sheet properties before and after aging. Various analyses were used, such as visual assessment by a universal serial bus (USB) digital microscope, mechanical properties, Fourier-transform infrared (FTIR) analysis, color change, and pH measurement. A dramatic increase in mechanical properties was observed after treatment. Besides, FTIR illustrated increasing of CH2 and OH stretching, which contribute to increasing the cellulose crystallinity index. There was no significant change in pH values after treatment or ageing. Slight changes of optical characteristics were observed for treated samples, after the artificial aging of the treated samples, the mechanical measurements showed that the values of tensile strength and elongation were close to the values of the standard sample, which may contribute to preventive protection of ZnO NP for treated samples from the artificial ageing.

scholarly journals Effects of equal channel angular pressing and heat treatments on the microstructures and mechanical properties of selective laser melted and cast AlSi10Mg alloys

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Przemysław Snopiński ◽  
Mariusz Król ◽  
Marek Pagáč ◽  
Jana Petrů ◽  
Jiří Hajnyš ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Equal Channel Angular Pressing ◽  
Heat Treatments ◽  
Electron Backscattered Diffraction ◽  
Angular Pressing ◽  
Low Temperature Annealing ◽  
Transmission Electron ◽  
Before And After ◽  
The Impact

AbstractThis study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.

scholarly journals Influence of Mo Additions on the Mechanical Properties of Cast Duplex Stainless Steels before and after Thermal Aging

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 295
Author(s):  
Shilei Li ◽  
Yanli Wang ◽  
Xitao Wang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Thermal Aging ◽  
Decomposition Kinetics ◽  
Before And After ◽  
Mo Content ◽  
Impact Energies ◽  
The Impact ◽  
Hardness Values ◽  
Mo Additions

The influence of Mo additions on the mechanical properties of cast duplex stainless steel (CDSS) before and after thermal aging was investigated using a series of model alloys with different Mo contents ranging from 0 to 1.75 wt%. By increasing Mo content, the content, morphology, and distribution of ferrite in CDSS change significantly. After thermal aging at 400 °C for 3000 h, the impact properties of all CDSS specimens obviously decline, and their hardness values in ferrite significantly increase. The impact energies of the aged CDSS decline, and the proportion of cleavage features significantly increases with Mo content increasing. The spinodal decomposition kinetics in ferrite is not significantly affected by the Mo contents. High content and interconnected ferrite will lead to the severe embrittlement in CDSS after thermal aging.

scholarly journals The degradation of mechanical properties in halloysite nanoclay–polyester nanocomposites exposed to diluted methanol

2016 ◽  
Vol 51 (11) ◽  
pp. 1653-1664 ◽  
Author(s):  
Mohd Shahneel Saharudin ◽  
Rasheed Atif ◽  
Islam Shyha ◽  
Fawad Inam
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Degradation Of Mechanical Properties ◽  
Before And After ◽  
The Matrix ◽  
Methanol Exposure ◽  
The Impact ◽  
And Storage ◽  
Methanol System ◽  
Methanol Absorption

The degradation of mechanical properties in halloysite nanoclay–polyester nanocomposites was studied after an exposure of 24 h in diluted methanol system by clamping test specimens across steel templates. The glass transition temperature ( Tg) and storage modulus increased steadily with the increase of halloysite nanoclays before and after diluted methanol exposure. The addition of nano-fillers was found to reduce liquid uptake by 0.6% in case of 1 wt% reinforcement compared to monolithic polyester. The mechanical properties of polyester-based nanocomposites were found to decrease as a result of diluted methanol absorption. After diluted methanol exposure, the maximum microhardness, tensile, flexural and impact toughness values were observed at 1 wt% of halloysite nanoclay. The microhardness increased from 203 to 294 HV (45% increase). The Young’s modulus increased from 0.49 to 0.83 GPa (70% increase) and the tensile strength increased from 23 to 27 MPa (17.4% increase). The impact toughness increased from 0.19 to 0.54 kJ/m2 in diluted methanol system (184% increase). Surprisingly, the fracture toughness of all types of nanocomposites was found to increase after exposing to diluted methanol due to plasticization effect. Scanning electron microscope images of the fractured surfaces of tensile specimens revealed that the methanol increased the ductility of the matrix and reduced the mechanical properties of the nanocomposites.

scholarly journals Polymer materials with controlled degradation time

2018 ◽  
Vol 44 ◽  
pp. 00122 ◽  
Author(s):  
Ewelina Niedzielska ◽  
Anna Masek
Keyword(s):  
Mechanical Properties ◽  
Uv Radiation ◽  
Color Change ◽  
Polymer Materials ◽  
Effect Of Temperature ◽  
Oxygen Effect ◽  
Cyclic Olefin Copolymer ◽  
Cyclic Olefin ◽  
Before And After

The aim of this work was carry out accelarated process of ageing for cyclic olefin copolymer ethylene – norbornene (Topas). The Topas cyclic olefin copolymer (COC) family characterize high transparency, excellent mechanical properties and low water permeability. The influence of external factors such as UV radiation, elevated temperature, oxygen effect and humidity causing degradation of polymer macroparticles was also investigated. The properties of the polymer before and after weathering and UV radiation were also compared. Degradability was examinated by measuring color change, FTIR spectrum analysis and determination of the ageing factor k. The tensile strength, elongation at break and hardness of composites by Shore A method were measured. The synergistic effect of temperature, humidity and UV radiation reduces the mechanical properties of the samples tested, while the interaction of only UV radiation on the samples causes a significant change color.

Comparative analysis of the impact of blood collection systems on the results of the study of indicators hemostasis system

2020 ◽  
Vol 65 (10) ◽  
pp. 607-610
Author(s):  
O. V. Petrova ◽  
O. V. Dymova ◽  
D. K. Tverdokhlebova ◽  
E. V. Smeltsova ◽  
E. V. Panova ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Visual Assessment ◽  
Blood Collection ◽  
Exclusion Criteria ◽  
Coagulation Tests ◽  
Before And After ◽  
Parametric Statistics ◽  
Inflammatory Drugs ◽  
The Impact ◽  
Routine Coagulation

Comparative analysis of the impact of blood collection systems on the results of routine coagulation tests. The aim of this study was to conduct comparative analysis of the effects of blood collection systems on the results of routine coagulation tests. The study involved practically healthy women over 18 years of age female (n=30). Inclusion criteria: practically healthy individuals. Exclusion criteria: taking non-steroidal anti-inflammatory drugs, or oral contraceptives. Blood collection was carried out in the following systems: 1 system-Vacuette Premium,2 system- Improvacuter, 3 system- BD Vacutainer® Plus. Before and after centrifugation, visual assessment of tubes was performed.No signs for the presence of clots, hemolysis, or insufficient filling was observed. In each sample we measured prothrombin time (PV, sec), activated partial thromboplastin time (APTT, sec), and fibrinogen (F, g/l) by clotting method on the automatic coagulometer «Sta Compact» («Diagnostica Stago», France). The results of laboratory analyses were processed using parametric and non - parametric statistics using The Statistica 12.0 software. At the preanalytical laboratory stage, there were no differences when using systems for blood sampling: the clots and hemolysis were not detected in the samples, the level of filling of the sistems was sufficient. Comparative analysis revealed small, though statistically significant, differences for: PT when comparing Improvacuter wiht Vacuette Premium or BD Vacutainer®; APPT when comparing Improvacuter wiht Vacuette Premium. No differences were observed for Fg levels. Our results support the data available in the literature on the effects of blood-taking systems on hemostasis , which should be taken into account when purchasing blood collection systems.

In situ investigation of the impact of cyclic thermal variations impact on the mechanical properties of sandy soil.

2020 ◽  
Author(s):  
Sandrine Rosin-Paumier ◽  
Hossein Eslami ◽  
Farimah Masrouri
Keyword(s):  
Mechanical Properties ◽  
Sandy Soil ◽  
In Situ Investigation ◽  
Energy Piles ◽  
Before And After ◽  
Cyclic Variations ◽  
Loading Tests ◽  
Adjacent Soil ◽  
Comparison Of The Results ◽  
The Impact

<p>The incorporation of heat exchangers into geostructures leads to changes in the temperature of the adjacent soil, which may affect its hydro-mechanical properties. In this study, mini-pressiometer tests were carried out in the vicinity of three experimental energy piles of 12 meters length and 0.52-meter diameter installed in saturated sandy soil. Tests were carried out in three locations and in two different depths (namely 3 and 4 meters in depth) before and after cyclic variations of their temperature. The pressuremeter parameters are the pressuremeter modulus EM, the limit pressure PL and the creep-pressure Pf. These parameters characterize the properties of the soils; some measurements were done close to the energy piles (1.25 meters from the center of the pile) using a mini-pressuremeter cell (380 mm in height and 28 mm in diameter). The comparison of the results before and after the four warming-cooling cycles (8° to 19° C) showed a thin thickening of the material at 3 meters depth. These results are coherent with in-lab measurements and with the results of the pile loading tests carried out later on the same site.</p>

Dynamic Thermal Mechanical Behaviors and Mechanical Properties of Reversible Thermochromism Wood-Plastic Composite

2017 ◽  
Vol 727 ◽  
pp. 571-578
Author(s):  
Yue Qin Wen ◽  
Ying Ying Sun ◽  
Jian Feng Xu ◽  
Jing Bing Chen ◽  
Xin Xiang Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Color Change ◽  
Loss Modulus ◽  
Wood Plastic Composite ◽  
Advantages And Disadvantages ◽  
Plastic Composite ◽  
Before And After ◽  
The Difference ◽  
Reversible Thermochromism

To prepare a late-model and functional wood-plastic composite (WPC), the reversible thermochromism crystal violet lactone microcapsule was prepared by situ polymerization, then fabricated reversible thermochromism WPC by microcapsule and low density polyethylene with Maleic anhydride grafted polyethylene. Comparing the L, a and b data of apparent color of reversible thermochromism WPC, the value of chromatism (ΔE) showed the difference of heating before and after, it was also measured to characterize the color-change level; the mechanical properties of ordinary WPC and reversible thermochromism WPC were measured respectively to compare the advantages and disadvantages of two kinds of WPC; Then the storage modulus and loss modulus of ordinary WPC and reversible thermochromism WPC were determined to distinguish the good from the bad of two kinds of composites. The results indicated that the reversible thermochromism WPC is a functional composite with noticeable color-changed effects, and tensile strength, bending strength and interface compatibility were better than ordinary WPC, but had worse impact property contrarily.

scholarly journals Polypropylene/ZnO Nanocomposites: Mechanical Properties, Photocatalytic Dye Degradation, and Antibacterial Property

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 914 ◽  
Author(s):  
Ampawan Prasert ◽  
Somchoke Sontikaew ◽  
Dilok Sriprapai ◽  
Surawut Chuangchote
Keyword(s):  
Mechanical Properties ◽  
Zno Nanoparticles ◽  
Dye Degradation ◽  
Antibacterial Properties ◽  
Sunlight Exposure ◽  
Zno Nanoparticle ◽  
Chemical Structures ◽  
Time Period ◽  
Before And After ◽  
Twin Screw

Nanocomposite materials were prepared by compounding polypropylene (PP) with zinc oxide (ZnO) nanoparticles, using a twin-screw extruder. The compound was molded by injection molding to form dumbbell-shaped specimens. The influence of ZnO nanoparticle content on the morphology, mechanical properties, chemical structure, photocatalytic activity, and antibacterial properties of the obtained nanocomposites was investigated. The morphological images showed that the ZnO nanoparticles were well distributed in the PP matrix. Characterizations of the mechanical properties and chemical structures before and after sunlight exposure found that at the shortest exposure time, crosslinks could occur in the nanocomposites, which resulted in improved mechanical properties. However, sunlight exposure with the time period longer than 18 weeks caused the reduction of the mechanical properties, due to degradation of the PP matrix. It was found that PP with 2% ZnO could achieve the photocatalytic degradation of methylene blue up to 59%. Moreover, the result of antibacterial tests indicated that the nanocomposites had better antibacterial properties than neat PP.

Effect of Heat Treatment on Microstructure Evolution and Mechanical Behavior of SKLB3 Alloy

2017 ◽  
Vol 898 ◽  
pp. 380-386
Author(s):  
Wei Yuan ◽  
Dong Mei Liu ◽  
Qiang Song Wang ◽  
Guo Liang Xie
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Energy ◽  
Hot Forging ◽  
Charpy Impact ◽  
Aging Treatment ◽  
Ni Alloy ◽  
Before And After ◽  
Different Temperatures ◽  
The Impact

In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.

A Study of the Influence of Strain Hardening and Precipitation Hardening Sequence on Development of Mechanical Properties of AlMgSi Conductor Alloys

2011 ◽  
Vol 690 ◽  
pp. 45-48
Author(s):  
Tadeusz Knych ◽  
Beata Smyrak ◽  
Piotr Osuch ◽  
Kinga Szajding
Keyword(s):  
Mechanical Properties ◽  
Precipitation Hardening ◽  
Power Transmission ◽  
Strength Properties ◽  
Point Of View ◽  
Artificial Ageing ◽  
Wire Rod ◽  
Study Results ◽  
The Impact ◽  
Almgsi Alloy

The paper focuses on 6xxx series AlMgSi conductor alloys. Such alloys are used for manufacturing of conductors for power transmission. Since the most current standards define as many as seven types of wires with various mechanical and electrical specifications, the existing philosophy of AlMgSi wires manufacturing technology for electrical applications has to be revised. Strength specifications of precipitation hardened AlMgSi alloys may be enhanced by strain and by precipitation hardening. Therefore from the scientific point of view identification seems to be relevant of the impact of the sequence of these mechanisms on development of final wire properties. In particular, this paper tries to answer the following question: Does the sequence of hardening mechanisms affect the development of mechanical properties of AlMgSi alloy wires? The paper presents results of a study of the impact of artificial ageing parameters of 6201 grade AlMgSi alloy wires on their final properties. The study results are presented and discussed in two parts. The first part addresses the impact of artificial aging temperature and duration on the strength properties of AlMgSi (grade 6201) alloy wire rod. The second part is focused on hardening development in the process of drawing of a AlMgSi wire made of the same alloy grade, subjected to different thermal treatments, the parameters of which have been selected based on analysis of the results of the first, wire-rod related, part of the study.

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