scholarly journals Investigation of the dispersion processes of composite colloidal capillary-porous materials

2019 ◽  
pp. 21-25
Author(s):  
Zh.O. Petrova ◽  
V.M. Vyshnievskyi ◽  
Yu.P. Novikova ◽  
A.I. Petrov
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Porous Materials ◽  
Material Flow ◽  
Maximum Yield ◽  
Flow Through ◽  
The Impact ◽  
First Time ◽  
Brittle State

The technology of drying colloidal capillary-porous materials to a final humidity of 6-8%, developed at the Institute of Technical Thermophysics of the NAS of Ukraine, allowed to obtain a brittle state, in which it is possible to grind this product to small particles. The most suitable for industrial grinding of the dried composite colloidal capillary-porous materials is the impact method, because when wiping and crushing the material has accumulated, stuck to the working surface. Powders are characterized by one pronounced maximum corresponding to the particle size of the powder of 0,16 mm. As the rotation speed of the shredder rotor changes, the particle size distribution of 0,16 mm increases by reducing the larger particles. The amount of powder thus obtained is directly proportional to the speed of rotation of the rotor. The study of the dispersion and classification of functional powders showed that all powders have the largest particle size of 0,16 mm. The maximum yield of this fraction is 70% and the lowest is 40%. The structural-mechanical characteristics of powders from composite colloidal capillary-porous materials were investigated for the first time.  Characteristics of different fractions were determined by such parameters as bulk density, vibration density, angle of natural slope, speed of material flow through the funnel and others. Studies to determine the structural and mechanical properties of functional powders have shown that they can be attributed to more bulk powders, as opposed to highly bound monopowders.  Creating compositions improves their structural and mechanical properties.

Effect of particle size, fiber content, and surface treatment on the mechanical properties of maple-reinforced LLDPE produced by rotational molding

2020 ◽  
pp. 096739112091660
Author(s):  
Fatima Ezzahra Hanana ◽  
Denis Rodrigue
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Surface Treatment ◽  
Tensile Modulus ◽  
Complete Characterization ◽  
Fiber Content ◽  
Wood Fibers ◽  
Interface Quality ◽  
Effect Of Particle Size ◽  
The Impact

In this work, composites based on linear low-density polyethylene and maple wood fibers with and without surface treatment with maleated polyethylene (MAPE) were prepared by dry blending, followed by rotomolding to study the effect of particle size, fiber content, and surface treatment. From the samples produced, a complete characterization of the morphological and mechanical properties was performed. The results obtained showed that MAPE surface treatment improved the fiber–matrix interface quality, which improved the homogeneity, the thermal stability, and the mechanical properties of the composites. The results showed that the effect of particle size was significant as the tensile modulus increased by 7%, 40%, and 73% for 125–250, 250–355, and 355–500 µm at 30 wt% of maple fibers. The tensile strength also increased by 114% at the same fiber loading (30 wt%) when the particle size increased from 125–250 µm to 355–500 μm. Finally, the impact strength with 355–500 µm particles was 52% higher than for 125–250 µm particles at 30 wt%

scholarly journals Recent Advances in Magnesia Blended Cement Studies for Geotechnical Well Construction—A Review

2021 ◽  
Vol 8 ◽  
Author(s):  
Weiqing Chen ◽  
Salaheldin Elkatatny ◽  
Mobeen Murtaza ◽  
Ahmed Abdulhamid Mahmoud
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Portland Cement ◽  
Supplementary Cementitious Materials ◽  
Research Progress ◽  
Size Analysis ◽  
Strength Testing ◽  
Cement Material ◽  
The Impact ◽  
Caustic Magnesia

The current paper presents a literature review on the studies of incorporation of magnesia (magnesium oxide) into Portland cement material from the geotechnical well construction perspective. Starting with a comparison of application conditions between civil construction and geotechnical well cementing, this work reviewed the Portland cement categorizations, magnesia manufacturing routes at first. Then, the physical-chemical-mechanical properties were investigated which includes the reactivity of magnesia, expansion influence from its hydration, and carbonation/dehydroxylation of magnesia blended Portland cement. The development of cement material hydration modeling methods is also summarized. Moreover, the experimental characterization methods have also been elucidated including composition determination, particle size analysis, volumetric variation measurement, compressive strength testing, shear-bond strength testing, transition state analysis, etc. Meanwhile, the results and conclusions were extracted from the literature. Through this route, a comprehensive understanding of the scientific research progress on magnesia blended Portland cement development for geotechnical well construction is derived. Additionally, it is concluded that incorporating magnesia into Portland cement can provide benefits for this material utilization in geotechnical well constructions provided the reasonable tuning among the characteristics of magnesia, the downhole surrounding conditions, and the formulation of the cement slurry. Satisfying these pre-conditions, the effective expansion not only mitigates the micro-annulus issues but also increases the shear bonding strength at the cementing interfaces. Moreover, the caustic magnesia introduction into Portland cement has the potential advantage on carbon dioxide geological sequestration well integrity compared with the Portland cement sheath without it because of the denser in-situ porous matrix evolvement and more stable carbon fixation features of magnesium carbonate. However, since the impact of magnesia on Portland cement strongly depended on its properties (calcination conditions, particle size, reactivity) and the aging conditions (downhole temperature, pressure, contacting medium), it should be noted that some extended research is worth conducting in the future such as the synchronized hydration between magnesia and Portland cement, the dosage limit of caustic magnesia in Portland cement in terms of CO2 sequestration and the corresponding mechanical properties analysis, and the hybrid method (caustic magnesia, Portland cement, and other supplementary cementitious materials) targeting the co-existence of the geothermal environment and the corrosive medium scenario.

Correlation of Holding Time and Bottom Ash Particle Size to Mechanical Properties of Polypropylene Composite

2020 ◽  
Vol 867 ◽  
pp. 172-181
Author(s):  
I Made Kastiawan ◽  
I Nyoman Sutantra ◽  
Sutikno
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Bending Strength ◽  
Bottom Ash ◽  
Holding Time ◽  
Polypropylene Composites ◽  
Time Variations ◽  
Polypropylene Matrix ◽  
The Impact ◽  
Initial Process

The impact of holding time and particle size of bottom ash on the mechanical properties of polypropylene composites has been investigated. The size of the used particle were 200-250, 250-300, and 300-350 mesh with the holding time variations were 0, 30, 60, and 90 minutes. The initial process of the bottom ash was cleaned with fresh and warm water, then drained and dried at a 120°C for 3 hours. In the making process of composites, the bottom ash was mixed into the polypropylene matrix by stirring at a speed of 20 rpm for 30 minutes. The results of this study showed that the highest composite strength values were obtained in composites with the particle size of 250-300 mesh. Tensile strength increased about 45% for composites without providing holding time (0 minutes), while the bending strength value increased significantly to 103% obtained on composites given a holding time of 30 minutes. The results of this study will be used as a basis for further research and hopes of getting better alternative engineering materials in the form of composites.

scholarly journals Effect of B4C particle size on the mechanical properties of B4C reinforced aluminum matrix layered composite

2019 ◽  
Vol 26 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Guangye Xu ◽  
Yingshui Yu ◽  
Yubo Zhang ◽  
Tingju Li ◽  
Tongmin Wang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Impact Strength ◽  
Mass Fraction ◽  
Ceramic Composites ◽  
Reinforcement Particle ◽  
The Impact ◽  
B4c Particle

Abstract Reinforcement particle size is very important for the performance of metal ceramic composites. This work studied the influence of B4C particle size on the mechanical properties of Al matrix layered composites. These composites were fabricated using a simplified semicontinuous casting and hot-rolling process. To obtain an optimized filling structure of particles, Horsfield filling principle was applied to determine the size and mass fraction of B4C particles. Four sizes of B4C particles were used with various combinations. The results showed that with the increase of the B4C particle size and fine B4C mass fraction, the hardness of the composites decreases whereas the impact strength and ultimate tensile strength increase. The residual stress at interface should be responsible for the variation in properties. Besides, the interparticle distance also contributes to the change in impact strength and ultimate tensile strength.

scholarly journals Effects of wild boar grazing on the yield of summer truffle (Tuscany, Italy)

2013 ◽  
Vol 48 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Elena Salerni ◽  
Lorenzo Gardin ◽  
Francesca Baglioni ◽  
Claudia Perini
Keyword(s):  
Wild Boar ◽  
Sampling Design ◽  
Forest Products ◽  
Negative Influence ◽  
Economic Damage ◽  
Fruiting Bodies ◽  
Tuber Aestivum ◽  
The Impact ◽  
First Time

The research presented here seeks to describe the impact of wild boar to a natural truffle ground of <em>Tuber aestivum </em>Vittad. on Monte Amiata (Tuscany – Italy). Pedoclimatic analyses indicated that the selected area could be considered suitable for the truffle production. Then classification of the vegetation of a <em>Quercus cerris </em>forest was carried out exploring the possibility of the BACI (Before-After-Control-Impact) sampling design. Finally 10 plots were selected, half of which have been fenced. For the first time the impact of wild boar was evaluated by estimating the surface area turned over by its activity. Moreover in each plot the number and weight of summer truffles was performed every 10 days during the fruiting period (June-November 2006-2008). The hypothesis that the presence of <em>Sus scrofa </em>has a strong negative influence on truffle harvesting has been amply confirmed by the data presented here, given the large increase of fruiting bodies of the summer truffle collected in the fenced plots. Consequently the destructive behaviour of the wild boar imply not only an ecological but also an economic damage in areas in which non-wood forest products are an important source of income.

scholarly journals Numerical Investigations of Film Cooling and Particle Impact on the Blade Leading Edge

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1102
Author(s):  
Ke Tian ◽  
Zicheng Tang ◽  
Jin Wang ◽  
Milan Vujanović ◽  
Min Zeng ◽  
...  
Keyword(s):  
Particle Size ◽  
Film Cooling ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Leading Edge ◽  
Turbine Engines ◽  
Small Particles ◽  
The Impact ◽  
First Time ◽  
Blade Leading Edge

As a vital power propulsion device, gas turbines have been widely applied in aircraft. However, fly ash is easily ingested by turbine engines, causing blade abrasion or even film hole blockage. In this study, a three-dimensional turbine cascade model is conducted to analyze particle trajectories at the blade leading edge, under a film-cooled protection. A deposition mechanism, based on the particle sticking model and the particle detachment model, was numerically investigated in this research. Additionally, the invasion efficiency of the AGTB-B1 turbine blade cascade was investigated for the first time. The results indicate that the majority of the impact region is located at the leading edge and on the pressure side. In addition, small particles (1 μm and 5 μm) hardly impact the blade’s surface, and most of the impacted particles are captured by the blade. With particle size increasing, the impact efficiency increases rapidly, and this value exceeds 400% when the particle size is 50 μm. Invasion efficiencies of small particles (1 μm and 5 μm) are almost zero, and the invasion efficiency approaches 12% when the particle size is 50 μm.

The impact of the particle size of a metal–organic framework for sulfur storage in Li–S batteries

2015 ◽  
Vol 3 (16) ◽  
pp. 8272-8275 ◽  
Author(s):  
Junwen Zhou ◽  
Xiaosong Yu ◽  
Xinxin Fan ◽  
Xiaojuan Wang ◽  
Haiwei Li ◽  
...  
Keyword(s):  
Particle Size ◽  
Metal Organic Framework ◽  
Cycling Stability ◽  
Metal Organic ◽  
Sulfur Host ◽  
The Impact ◽  
First Time ◽  
Organic Framework

We report for the first time the influence of the particle size of a porous sulfur host on the sulfur utilization and cycling stability of Li–S batteries.

scholarly journals Pictographemes in the Ergonyms of Irkutsk: General and Specific Functions

2020 ◽  
pp. 113-126
Author(s):  
S. N. Lokhov
Keyword(s):  
Direct Reference ◽  
Subject Area ◽  
Main Function ◽  
Linguistic Research ◽  
New Type ◽  
The Impact ◽  
First Time ◽  
A Company

The features of the application of pictographemic elements in the ergonomics of Irkutsk are discussed in the article. The trends in the study of creolized texts in modern linguistics are characterized. The basic means of the actual transformation of the ergonym form are noted. It is established that one of the means is a pictographeme, an image that combines the features of a grapheme and a pictogram. The reasons for the use of pictographemes in the structure of the word are considered on the example of the ergonyms of Irkutsk. The relevance of the study is due to the need to assess the effectiveness of the impact of pictographic tools on the audience. The novelty of the work is seen in the fact that a new factual material, the ergonyms of Irkutsk, was introduced into the circulation of linguistic research. This made it possible for the first time to consider the specifics of pictographemes as a new type of interaction on ergonomic material between verbal and visual components in “city writing”. The results of the analysis of the functioning of pictographemes in the ergonyms of Irkutsk are presented. The main function - the secondary explication of meaning, actualized primarily in the name of a company, institution or enterprise is established. It is revealed that this is due to the need to memorize the ergonym, as well as to ensure ease of perception. The classification of particular functions of pictographemes is proposed: 1) direct actualization of the name and indirect designation of the goods; 2) presentation and designation of goods by direct reference to the necessary subject area; 3) presentation of the properties of the proposed product due to building the necessary associative nomination for the author.

The Mechanical Properties of Soils with Uneven Grain-Size Distribution

2014 ◽  
Vol 1073-1076 ◽  
pp. 1689-1696
Author(s):  
Zaven Ter-Martirosyan ◽  
Anatoly Mirnyy ◽  
Armen Ter-Martirosyan
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Granulometric Composition ◽  
Strain State ◽  
Analytic Solutions ◽  
Diameter Ratio ◽  
Selection For ◽  
Stress States ◽  
The Impact

This issue deals with peculiarities of stress-strain state forming in a representative volume of inhomogeneous soil. Analytic solutions for describing such stress states and obtaining equivalent mechanical values for such massive are given. Basing on the performed triaxial laboratory tests the impact of diameter ratio, percentage, and contact between particles on mechanical properties of a mixture is estimated. As a conclusion some recommendations on using the research results in practical geotechnical engineering are given. The classification of inhomogeneous soils, based on granulometric data, allowing to estimate mechanical properties is presented, as a method of granulometric composition, humidity and density selection for artificial foundations.

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