Factors Affecting the Stiffening Potential of Mineral Fillers

1998 ◽  
Vol 1638 (1) ◽  
pp. 94-100 ◽  
Author(s):  
Naga Shashidhar ◽  
Pedro Romero
Keyword(s):  
Average Particle Size ◽  
Asphalt Mixture ◽  
Quantitative Relationship ◽  
Packing Fraction ◽  
Complex Problem ◽  
Average Particle ◽  
Factors Affecting ◽  
And Performance ◽  
Two Parameters ◽  
Mineral Fillers

The workability and performance of bituminous mixes is known to be affected by the filler-asphalt mixture (or mastic) properties. The addition of fillers is known to stiffen asphalt. The degree of stiffening is a function of several filler and asphalt properties, which are not well understood. A fundamental approach to understanding the influence of such factors on the stiffening potential of filler in asphalt is discussed. This complex problem is simplified by introducing two intermediate measurable parameters, the maximum packing fraction, ϕ m, and the generalized Einstein coefficient, KE. This enables a better understanding of the influence of various factors such as average particle size, gradation, particle shape, presence of agglomerates, degree of dispersion, and the asphalt-filler interface on the stiffening potential of asphalt. First, the relationship between these two parameters and stiffening is thoroughly examined. The physical meaning of these parameters is discussed. Second, the influence of each factor on stiffening potential is addressed individually, supported by experimental data and relevent literature to derive a quantitative relationship. Finally, the relative advantages of the approach over the traditional treatment are discussed. It is further shown that, since the parameters φm and KE take into account the properties of an asphalt-filler system as a whole, they are likely to predict stiffening more accurately than Rigden’s fractional voids approach which is based on the properties of fillers alone.

scholarly journals Evaluation of the Effects of Filler Fineness on the Properties of an Epoxy Asphalt Mixture

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2003
Author(s):  
Wei Xu ◽  
Jintao Wei ◽  
Zhengxiong Chen ◽  
Feng Wang ◽  
Jian Zhao
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Asphalt Mixture ◽  
Average Particle ◽  
Fine Dust ◽  
Bonding Structure ◽  
Epoxy Asphalt ◽  
Mineral Powder ◽  
Marshall Stability ◽  
Mixture Sample

The type and fineness of a filler significantly affect the performance of an asphalt mixture. There is a lack of specific research on the effects of filler fineness and dust from aggregates on the properties of epoxy asphalt (EA) mixtures. The effects of aggregate dust and mineral powder on the properties of an EA mixture were evaluated. These filler were tested to determine their fineness, specific surface area and mineral composition. The effects of these fillers on the EA mastic sample and mixture were evaluated. The morphology of the EA mastic samples was analyzed using scanning electron microscopy (SEM). The effects of the fillers on the Marshall stability, tensile strength and fatigue performance of the EA mixture were evaluated. The dust from the aggregates exhibited an even particle size distribution, and its average particle size was approximately 20% of that of the mineral powder. The SEM microanalysis showed that the EA mastic sample containing relatively fine dust formed a tight and dense interfacial bonding structure with the aggregate. The EA mixture sample containing filler composed of dust from aggregate had a significantly higher strength and longer fatigue life than that of the EA sample containing filler composed of mineral powder.

Low-Temperature Cracking Analysis of Asphalt Pavement

2013 ◽  
Vol 361-363 ◽  
pp. 1625-1628
Author(s):  
Zhao Sheng Li ◽  
Yi Qiu Tan
Keyword(s):  
Low Temperature ◽  
Asphalt Pavement ◽  
Average Particle Size ◽  
Asphalt Mixture ◽  
Average Particle ◽  
Aggregate Gradation ◽  
Cracking Behavior ◽  
Behavior Study ◽  
Low Temperature Cracking ◽  
Shrinkage Coefficient

Establish the mechanical model of asphalt pavement low-temperature cracking, analysis the factors leading to cracking. The factors such as shrinkage coefficient of asphalt pavementtemperature stresspavement structure combination forms and temperature contribution affect the asphalt pavement on cracking behavior. Study the effect of aggregate gradation type on asphalt mixture temperature shrinkage coefficient, analyze shows that in case of the same skeleton type, the smaller the average particle size of aggregate is, the larger low-temperature shrinkage deformation of mixture is; increasing the amount of coarse aggregate can form the dense structure of skeletonreduce the shrinkage coefficient at low temperature and improve the low-temperature crack resistance ability of asphalt mixture.

Preparation and Performance of Mesoporous TiO2 Photocatalyst with P123 as Template

2016 ◽  
Vol 680 ◽  
pp. 198-202
Author(s):  
Chao Wang ◽  
Si Qin Zhao ◽  
S. Asuha
Keyword(s):  
Particle Size ◽  
Photocatalytic Activity ◽  
Degradation Rate ◽  
Average Particle Size ◽  
Bet Surface Area ◽  
Average Particle ◽  
Hydrothermal Time ◽  
Hydrothermal Temperature ◽  
Type Iv ◽  
And Performance

In this paper, a series of mesoporous TiO2 photocatalyst were prepared by hydrothermal method using block copolymer P123 as template and Ti (OBu)4 as titanium source. The microstructure and spectroscopy performance of the prepared TiO2 were characterized by means of XRD, SEM, TEM, BET, and BJH analysis, and the photocatalytic activity of mesoporous TiO2 were examined by measuring the photodegradation of methyl orange , then discussed the best prepared conditions of mesoporous TiO2 photocatalyst. The results showed that the products were all anatase mesoporous TiO2 nanopowder, the average particle size is about 7nm and all have the Langmuir type IV pore structure. The best prepared condition: hydrothermal temperature is 160°C, hydrothermal time is 24h, mesoporous TiO2 photocatalyst has the BET surface area of 146m2/g , it’s photocatalytic degradation rate is 97.07% in an hour.

Functional Study of the Limb Lymphatic System

1986 ◽  
Vol 1 (2) ◽  
pp. 129-133 ◽  
Author(s):  
A. Pecking ◽  
R. Cluzan ◽  
J.P. Desprez-Curely ◽  
P. Guérin
Keyword(s):  
Injection Site ◽  
Half Life ◽  
Lymphatic System ◽  
Average Particle Size ◽  
Lymphatic Drainage ◽  
Functional Study ◽  
Average Particle ◽  
Time Activity ◽  
Radionuclide Lymphoscintigraphy ◽  
Two Parameters

Radionuclide lymphoscintigraphy with rhenium sulphide colloid (RSC), average particle size 40 nm was used as a functional test of the limb lymphatic system. When injected subcutaneously in the hand or the foot all the RSC which leave the injection site enters the lymphatic system. From the disappearance time-activity curve detected over the injection site, we calculated the half-life and the lymphatic colloidal clearance (LC) of the RSC. These two parameters appeared to be closely depending on the macrophage function and on the permeability of the initial lymphatics. We also measured the necessary time for RSC to reach the knee or the elbow and calculated a lymphatic speed (LS) closely related to the lymph flow. The study was first carried out on 40 healthy volunteers and then on 221 patients with limb lymphoedemas. The reproducibility of the method was good when 4 days at least separate two functional tests ( r = 0.95 for half-life, r = 0.86 for lymphatic clearance at the injection site and r = 0.93 for lymphatic speed). In addition with the lymphatic images detected 1 h after the injection the functional study may become a useful technique to differentiate the lymphatic drainage diseases.

Optimum formulation derivation for the ultimate packing fraction using monodispersed particle sizes when optimizing suspension viscosities

2019 ◽  
Vol 48 (1) ◽  
pp. 45-56
Author(s):  
Richard D. Sudduth
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Packing Fraction ◽  
Size Ratio ◽  
Average Particle ◽  
Particle Sizes ◽  
Monodisperse Particle ◽  
Content Type ◽  
Particle Size Ratio ◽  
Minimum Number

Purpose The importance of maximizing the particle packing fraction in a suspension by maximizing average particle size ratio of D5/D1 has been adequately shown to be important as previously reported in the literature. This study aims to extend that analysis to include the best formulation approach to maximize the packing fraction with a minimum number of monodisperse particle sizes. Design/methodology/approach An existing model previously developed by this author was modified theoretically to optimize the ratio used between consecutive monodisperse particle sizes. This process was found to apply to a broad range of particle configurations and applications. In addition, five different approaches for maximizing average particle size ratio D̅5/D̅1 were addressed for blending several different particle size distributions. Maximizing average particle size ratio D̅5/D̅1 has been found to result in an optimization of the packing fraction. Several new concepts were also introduced in the process of maximizing the packing fraction for these different approaches. Findings The critical part of the analysis to maximize the packing fraction with a minimum number of particles was the theoretical optimization of the ratio used between consecutive monodisperse particle sizes. This analysis was also found to be effectively independent of the maximum starting particle size. This study also clarified the recent incorrect claim in the literature that Furnas in 1931 was the first to generate the maximum theoretical packing fraction possible for n different particles that was actually originally developed in conjunction with the Sudduth generalized viscosity equation. In addition, the Furnas generated equation was also shown to give significantly different results from the Sudduth generated equation. Research limitations/implications Experimental data involving monodisperse particles of different blends with a minimum number of particle sizes that are truly monodisperse are often extremely difficult to obtain. However, the theoretical general concepts can still be applicable. Practical implications The expanded model presented in this article provides practical guidelines for blending pigments using a minimum number of monodisperse particle sizes that can yield much higher ratios of the particle size averages D̅5/D̅1 and thus potentially achieve significantly improved properties such as viscosity. Originality/value The model presented in this article provides the first apparent guidelines to control the blending of pigments in coatings by the optimization of the ratio used between consecutive monodisperse particle sizes. This analysis was also found to be effectively independent of the maximum starting particle size.

scholarly journals Fabrication and characterisation of Fe2O3/chitosan aerogel-like spheres

2021 ◽  
Vol 10 (1) ◽  
pp. 74-78
Author(s):  
Nhan Dang Thi Thanh ◽  
Don Truong Thi ◽  
Thang Le Quoc ◽  
Tien Tran Dong ◽  
Son Le Lam
Keyword(s):  
High Surface ◽  
Sol Gel ◽  
Average Particle Size ◽  
High Surface Area ◽  
Hollow Structure ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
Sol Gel Process ◽  
High Surface Area Materials

Presently, biopolymer materials have been given more attention for their outstanding properties, high efficiencies and promising applications in various fields. In this study, Fe2O3/chitosan aerogel-like spheres were successfully prepared from chitosan and FeCl3 by sol–gel process and freeze-drying to provide high-surface area materials. The factors affecting the material synthesis have been studied. The asprepared Fe2O3/chitosan material was characterized by Infrared Spectroscopy (IR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) methods. The results showed that the aerogel spheres have a hollow structure made of chitosan nanofibril networks. Fe2O3 nanoparticles get high crystallinity and have an average particle size of 33 nm.

Green Synthesis of NiO Nanoparticle Using Ziziphus Spina-Christi Leaves Extract for Photocatalytic Methylene Blue Dye Degradation

2021 ◽  
Vol 13 (9) ◽  
pp. 1756-1763
Author(s):  
Hamdah S. Alanazi ◽  
Hanan Alotaibi ◽  
Hamza S. Al-Shehri ◽  
Fahad A. Alharthi
Keyword(s):  
Methylene Blue ◽  
Environmental Remediation ◽  
Dye Degradation ◽  
Uv Light ◽  
Average Particle Size ◽  
Active Species ◽  
Wide Bandgap ◽  
Blue Dye ◽  
Average Particle ◽  
Factors Affecting

In this presented work, ziziphus spina-christi leaves extract assisted green synthesise approach was used to prepare the NiO nanoparticle for UV light driven photocatalytic methylene blue (MB) dye degradation. Various analytical characterizations were used to understand the crystalline, structural, optical and morphological nature of the prepared nanoparticle. The prepared NiO nanoparticle have wide bandgap of 3.35 eV with average particle size of around 10–15 nm in range. Various environmental conditions and elemental trapping experiments were conducted to understand the factors affecting the MB degradation and main active species for the redox reaction. Hence, we hope that this green synthesise NiO would pave a new way for photocatalytic preparation and their environmental remediation application.

The Effect of Particle Sizes on the Concentration Dependence of the Surface Tension of Aqueous Suspensions of Bentonite

2021 ◽  
Vol 1022 ◽  
pp. 212-217
Author(s):  
R.Kh. Dadashev ◽  
R.S. Dzhambulatov ◽  
Z.S. Khasbulatova ◽  
Kh.S. Talkhigova
Keyword(s):  
Surface Tension ◽  
Solid Phase ◽  
Aqueous Suspension ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Coarse Particles ◽  
Factors Affecting ◽  
Aqueous Suspensions ◽  
Surface Tension Isotherms

The paper presents experimental results on the dependence of surface tension on the concentration of a suspension of bentonite (0 - 10% by weight). The isotherms σ of aqueous suspensions of bentonite are characterized by local minima in the concentration range of 3-4 mass% of the solid phase. It has been established that a decrease in the average particle size leads to the disappearance of the extremum on the surface tension isotherms. The data obtained led to the conclusion that the most important factors affecting the nature of the isotherms of the surface tension of bentonite suspensions are the degree of dispersion and the presence in the aqueous suspension of bentonite, both colloidal and coarse particles.

Hygienic assessment of learning environment conditions (by the example of higher educational institutions of the city of Ufa)

2020 ◽  
Vol 99 (4) ◽  
pp. 405-411
Author(s):  
Elena Ju. Gorbatkova
Keyword(s):  
Ionizing Radiation ◽  
Educational Institutions ◽  
Higher Educational Institutions ◽  
Factors Affecting ◽  
Republic Of Bashkortostan ◽  
Average Relative Humidity ◽  
Higher Educational ◽  
The Republic ◽  
And Performance ◽  
The City

Introduction. The important factors affecting health and performance of young people are the conditions of education, in particular, a comfortable microclimate in the classrooms of higher educational institutions. Materials and methods. In view of the urgency of this problem, an analysis was made of the microclimate parameters of educational organizations of different profiles (Ufa city, the Republic of Bashkortostan). 294 classrooms were studied in 22 buildings of 4 leading universities in Ufa. A total of 3,822 measurements were taken to determine the parameters of the microclimate. The analysis of ionizing radiation in the aerial environment of classrooms. There was performed determination of radon and its affiliated products content. In order to assess the conditions and lifestyle of students of 4 higher educational institutions of the city of Ufa, we conducted an anonymous survey of 1,820 students of I and IV years of education. Results. The average temperature in the classrooms of all universities studied was 23.9±0.09 C. The average relative humidity in all classrooms was 34.2 ± 0.42%. Analysis of ionizing radiation (radon and its daughter products decay) in the aerial environment of the classrooms and sports halls located in the basement determined that the average annual equivalent equilibrium volumetric activity of the radon daughter products (EROA ± Δ222Rn) ranged from 28 ± 14 to 69 ± 34.5 meter, which meets the requirements established by SanPiN. Conclusion. The hygienic assessment of the microclimate parameters of educational institutions of various profile revealed a number of deviations from the regulated norms. The results indicate the need to control the parameters of the microclimate, both from the administration of universities, and from the professors. According to the results of the study, recommendations were prepared for the management of higher educational institutions in Ufa.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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