scholarly journals A Review on Bitumen Rejuvenation: Mechanisms, Materials, Methods and Perspectives

2019 ◽  
Vol 9 (20) ◽  
pp. 4316 ◽  
Author(s):  
Loise ◽  
Caputo ◽  
Porto ◽  
Calandra ◽  
Angelico ◽  
...  
Keyword(s):  
Complex Systems ◽  
Chemical Structure ◽  
Structural Changes ◽  
Ad Hoc ◽  
State Of The Art ◽  
Chemical Interaction ◽  
The State ◽  
X Ray ◽  
X Ray Scattering ◽  
Novel Approach

This review aims to explore the state of the knowledge and the state-of-the-art regarding bitumen rejuvenation. In particular, attention was paid to clear things up about the rejuvenator mechanism of action. Frequently, the terms rejuvenator and flux oil, or oil (i.e., softening agent) are used as if they were synonymous. According to our knowledge, these two terms refer to substances producing different modifications to the aged bitumen: they can decrease the viscosity (softening agents), or, in addition to this, restore the original microstructure (real rejuvenators). In order to deal with the argument in its entirety, the bitumen is investigated in terms of chemical structure and microstructural features. Proper investigating tools are, therefore, needed to distinguish the different mechanisms of action of the various types of bitumen, so attention is focused on recent research and the use of different investigation techniques to distinguish between various additives. Methods based on organic synthesis can also be used to prepare ad-hoc rejuvenating molecules with higher performances. The interplay of chemical interaction, structural changes and overall effect of the additive is then presented in terms of the modern concepts of complex systems, which furnishes valid arguments to suggest X-ray scattering and Nuclear Magnetic Resonance relaxometry experiments as vanguard and forefront tools to study bitumen. Far from being a standard review, this work represents a critical analysis of the state-of-the-art taking into account for the molecular basis at the origin of the observed behavior. Furnishing a novel viewpoint for the study of bitumen based on the concepts of the complex systems in physics, it constitutes a novel approach for the study of these systems.

scholarly journals Small Angle X-Ray Scattering Technique for the Particle Size Distribution of Nonporous Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
A. Agbabiaka ◽  
M. Wiltfong ◽  
C. Park
Keyword(s):  
Small Angle ◽  
State Of The Art ◽  
Accurate Determination ◽  
The State ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Technique ◽  
Art Methods ◽  
Nanoparticle Sizes ◽  
Ray Scattering

Nanoparticles are small particles whose sizes are less than 100 nm. They have many industrial applications due to their unique properties. Their properties are often size-dependent; thus the accurate determination of nanoparticle sizes is important for quality assurance of nanoparticle production processes. A small angle X-ray scattering technique is a promising method used for characterizing nanoparticle sizes. It has distinctive advantages over other techniques such as electron microscope techniques. In this paper, we review the state-of-the-art methods for determining the sizes of nanoparticles with small angle X-ray experiments and discuss the advantages and limitations of the state-of-the-art methods.

scholarly journals Density Guarantee on Finding Multiple Subgraphs and Subtensors

2021 ◽  
Vol 15 (5) ◽  
pp. 1-32
Author(s):  
Quang-huy Duong ◽  
Heri Ramampiaro ◽  
Kjetil Nørvåg ◽  
Thu-lan Dam
Keyword(s):  
Lower Bound ◽  
State Of The Art ◽  
The State ◽  
The Other ◽  
Exact Methods ◽  
Practical Solution ◽  
Novel Approach ◽  
Wide Range ◽  
Real World Datasets ◽  
Tensor Data

Dense subregion (subgraph & subtensor) detection is a well-studied area, with a wide range of applications, and numerous efficient approaches and algorithms have been proposed. Approximation approaches are commonly used for detecting dense subregions due to the complexity of the exact methods. Existing algorithms are generally efficient for dense subtensor and subgraph detection, and can perform well in many applications. However, most of the existing works utilize the state-or-the-art greedy 2-approximation algorithm to capably provide solutions with a loose theoretical density guarantee. The main drawback of most of these algorithms is that they can estimate only one subtensor, or subgraph, at a time, with a low guarantee on its density. While some methods can, on the other hand, estimate multiple subtensors, they can give a guarantee on the density with respect to the input tensor for the first estimated subsensor only. We address these drawbacks by providing both theoretical and practical solution for estimating multiple dense subtensors in tensor data and giving a higher lower bound of the density. In particular, we guarantee and prove a higher bound of the lower-bound density of the estimated subgraph and subtensors. We also propose a novel approach to show that there are multiple dense subtensors with a guarantee on its density that is greater than the lower bound used in the state-of-the-art algorithms. We evaluate our approach with extensive experiments on several real-world datasets, which demonstrates its efficiency and feasibility.

Photoinduced structural changes in amorphousAs2S3as measured by differential anomalous x-ray scattering

1995 ◽  
Vol 52 (14) ◽  
pp. 10025-10034 ◽  
Author(s):  
Qing Ma ◽  
Weiqing Zhou ◽  
D. E. Sayers ◽  
M. A. Paesler
Keyword(s):  
Structural Changes ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Thermotropic behavior of sodium cholesteryl carbonate

2009 ◽  
Vol 24 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Rabkwan Chuealee ◽  
Timothy S. Wiedmann ◽  
Teerapol Srichana
Keyword(s):  
Phase Behavior ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
C Nmr

Sodium cholesteryl carbonate ester (SCC) was synthesized, and its phase behavior was studied. The chemical structure was assessed by solid-state infrared spectroscopy based on vibration analysis. The wave number at 1705 and 1276 cm−1 corresponds to a carbonyl carbonate and O–C–O stretching of SCC, respectively. Molecular structure of SCC was further investigated with 1H and 13C NMR spectroscopy. The chemical shift, for the carbonyl carbonate resonance appeared at 155.5 ppm. A molecular mass of SCC was at m/z of 452. Differential scanning calorimetry (DSC), video-enhanced microscopy (VEM) together with polarized light microscopy, and small-angle x-ray scattering (SAXS) were used to characterize the phase behavior as a function of temperature of SCC. Liquid crystalline phase was formed with SCC. Based on the thermal properties and x-ray diffraction, it appears that SCC forms a structure analogous to the type II monolayer structure observed with cholesterol esters.

Multilayer X-Ray Mirrors; The State Of The Art.

1988 ◽  
Author(s):  
M P. Bruijn ◽  
J. Verhoeven ◽  
E. Puik ◽  
M J. van der Wiel
Keyword(s):  
State Of The Art ◽  
The State ◽  
X Ray

Small angle X-ray scattering study of structural changes in silica gel modified with organofunctional groups

1989 ◽  
Vol 40 ◽  
pp. 1-8 ◽  
Author(s):  
Dimas R. Vollet ◽  
José C. Moreira ◽  
Lauro T. Kubota ◽  
José A. Varela ◽  
Yoshitaka Gushikem
Keyword(s):  
Silica Gel ◽  
Small Angle ◽  
Structural Changes ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering
Sign in / Sign up

Export Citation Format

Share Document