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In this letter, we apply reverse Cuthill-McKee (RCM) algorithm to transform two-electron integral tensors to their block diagonal forms. By further applying Cholesky decomposition (CD) on each of the diagonal blocks, we are able to represent the high-dimensional two-electron integral tensors in terms of permutation matrices and low-rank Cholesky vectors. This representation facilitates low-rank factorizations of high-dimensional tensor contractions in post-Hartree-Fock calculations. Here, we discuss the second-order Møller-Plesset (MP2) method and the linear coupled-cluster model with doubles (L-CCD) as examples to demonstrate the efficiency of this technique in representing the two-electron integrals in a compact form. [ABSTRACT FROM AUTHOR]

The objectives of this paper are foresight study of the anticipated needs and requirements as well as identification of development directions of materials and technologies for use in road construction in the time perspective of approximately 30 years. In order to address this goal, Delphi forecasting method was utilized in the Polish-nationwide study with 150 invited experts. Paper presents results of research project dealing with development of directions of road pavement technologies with regards to the environmental aspects. As a result of the analyses, it was concluded that binding materials with improved viscoelastic range (often with modifications) would continue to play a leading role. Furthermore, according to the experts, the technologies that enable to monitor the state of road pavement in a continuous manner will be used to a greater range. Introduction of sensors into the pavement network will lead to the construction of “smart” roads while the spread of nanomaterial technologies in road construction will improve the durability and reliability of road pavement construction. [ABSTRACT FROM AUTHOR]

Polyacenes have attracted considerable attention due to their various applications in organic optoelectronic materials. This study focuses on linear polyacenes and their electron affinity (EA) and ionization potential (IP) properties. We have employed our recent implementation of EA/IP equation of motion coupled cluster singles and doubles (EA/IP-EOMCCSD) methods which are accurate, computationally efficient and are capable of treating large systems employing reasonable basis sets size. The EA/IP results obtained for naphthalene, anthracene, tetracene, pentacene, hexacene and heptacene are in a good agreement with experiment. Comparison between quality of excitation energies obtained from IP-EOMCCSD and EE-EOMCCSD formalisms were also studied. [ABSTRACT FROM AUTHOR]

Construction of a durable bituminous pavements requires high quality materials such as e.g. polymer modified bitumen (PMB) with extended viscoelastic properties. The main objective of this paper is to analyse the influence of microstructure of PMB on their high temperature viscoelastic properties and to assess appropriate modifier content. The multiple stress creep recovery (MSCR) procedure tests were conducted to evaluate viscoelastic properties together with fluorescent microscopy used to examine the microstructure of binders. Based on a conventional tests (penetration, softening point, elastic recovery and Fraass breaking point) as well as recovery and non-recoverable creep compliance obtained from MSCR test, amount of an appropriate modifier content was analysed. It was concluded, that although bituminous binders complies with European specification requirements, they are significantly different in terms of their morphology and rheological properties due to the dispersed polymer phase and polymer content. It was found that PMBs within the same hardness group exhibit different high temperature properties. Correlation between polymer phase area and empirical curve from MSCR test for asses proper polymer content was established. [ABSTRACT FROM AUTHOR]

Abstract: The optimization of tensor expressions with hundreds of terms is required for the development of accurate quantum chemistry models such as the coupled cluster method. In this paper, we address the effective exploitation of symmetry properties of tensors in performing algebraic transformations for minimizing operation count of tensor expressions. We develop rules to detect symmetries in intermediate tensors, cost models for tensor contractions with symmetries, and a canonical representation to facilitate effective common subexpression elimination. We demonstrate significant improvements to the operation counts for the coupled cluster method when compared to several state-of-the-art im-plementations. Furthermore, we show that tensor expressions optimized for a few input parameter combinations can be used to achieve operation counts within 3% of the optimal, for the entire parameter space of interest. [Copyright &y& Elsevier]

Abstract: A new class of non-iterative coupled-cluster (CC) methods, which improve the results of standard CC and equation-of-motion (EOM) CC calculations for ground and excited-state potential energy surfaces along bond breaking coordinates and for excited states dominated by two-electron transitions, is explored. The proposed approaches combine the method of moments of coupled-cluster equations (MMCC), in which the a posteriori corrections due to higher-order correlations are added to standard CC/EOMCC energies, with the multi-reference many-body perturbation theory (MRMBPT), which provides information about the most essential non-dynamic and dynamic correlation effects that are relevant to electronic quasi-degeneracies. The performance of the basic MRMBPT-corrected MMCC approximation, in which inexpensive non-iterative corrections due to triple excitations are added to ground- and excited-state energies obtained with the CC/EOMCC singles and doubles approach, is illustrated by the results of a few test calculations, including bond breaking in HF and H2O, and excited states of CH+. [Copyright &y& Elsevier]

Abstract: Noniterative inclusion of the higher-order clusters has been a subject of intensive studies aimed at developing a well balanced description of individual many-body contributions for entire ground-state potential energy surfaces. In traditional approaches, the connected quadruples are estimated directly based on perturbative arguments, which leads to excellent agreement with full CI results near the equilibrium geometry and increasingly worse energies for larger internuclear stretches. As a possible improvement to this situation, two techniques are considered as especially promising: perturbative approaches based on the similarity transformed Hamiltonians and renormalization schemes both in global and local formulations. Following the latter strategy we adopted the recently introduced numerator–denominator connected expansion (NDC) [K. Kowalski, P. Piecuch, J. Chem. Phys. 122 (2005) 074107] as an effective tool for designing new forms of noniterative corrections accounting for the joint effect of triples and quadruples. The performance of the ensuing locally renormalized CCSD(TQ) approaches (LR-CCSD(TQ)) is illustrated on several examples that require either going beyond the triples approximation or describing very subtle effects encountered in van der Waals complexes. Comparisons with other noniterative approaches are also made and some issues regarding the size-extensivity of the locally renormalized methods are addressed. [Copyright &y& Elsevier]

• Pavement biomass materials are divided into bio-oil, bio-fiber, bio-filler. • Pavement biomass materials from source to application were reviewed. • Composite modification can increase the content and utilization of bio-oil. • The latest performance research results of road biomass materials were compared. T o cope with the global climate crisis and assist in achieving the carbon neutrality, the use of biomass materials to fully or partially replace petroleum-based products and unrenewable resources is expected to become a widespread solution. Based on the analysis of the existing literature, this paper firstly classified biomass materials with potential application prospects in pavement engineering according to their application and summarized their respective preparation methods and characteristics. The pavement performance of asphalt mixtures with biomass materials was analyzed and summarized, and the economic and environmental benefits of bio-asphalt binder were evaluated. The analysis shows that pavement biomass materials with potential for practical application can be divided into three categories: bio-oil, bio-fiber, and bio-filler. Adding bio-oil to modify or extend the virgin asphalt binder can mostly improve the low temperature performance of asphalt binder. Adding styrene-butadienestyrene (SBS) or other preferable bio-components for composite modification will have a further improved effect. Most of the asphalt mixtures prepared by using bio-oil modified asphalt binders have improved the low temperature crack resistance and fatigue resistance of asphalt mixtures, but the high temperature stability and moisture resistance may decrease. As a rejuvenator, most bio-oils can restore the high and low temperature performance of aged asphalt and recycled asphalt mixture, and improve fatigue resistance. Adding bio-fiber could significantly improve the high temperature stability, low temperature crack resistance and moisture resistance of asphalt mixtures. Biochar as a bio-filler can slow down the asphalt aging process and some other bio-fillers can improve the high temperature stability and fatigue resistance of asphalt binders. Through calculation, it is found that the cost performance of bio-asphalt has the ability to surpass conventional asphalt and has economic benefits. The use of biomass materials for pavements not only reduces pollutants, but also reduces the dependence on petroleum-based products. It has significant environmental benefits and development potential. [ABSTRACT FROM AUTHOR]

Lithium clusters Li n ( n = 1–20) have been investigated with density functional theory (DFT) and coupled-cluster (CC) methods. The global minima are located via an improved basin-hopping algorithm. Simulated polarizabilities are in good agreement with the measured data generally. The simulated polarizabilities for Li 6 , Li 12 and Li 19 are in reasonable agreement when thermal effects are included, except the Li 3 cluster. A linear correlation for the inverse relationship between the CCSD calculated polarizabilities and ionization potential (IP) has been reported to have the linear coefficient of 0.996, which further strengthens our simulations. [ABSTRACT FROM AUTHOR]

Highlights: [•] TD-DFT QM/MM MD is used to elucidate the emission spectrum of PRODAN in water. [•] The planar PRODAN conformer is predominantly responsible for fluorescence in water. [•] Water stabilizes the twisted PRODAN conformer but its emission is weak. [•] Extended water environment and solvent polarization influence PRODAN emission. [Copyright &y& Elsevier]

• The feasibility of using 12 alternative friction aggregates in HFST was evaluated. • Taconite could be a suitable alternative aggregate source for HFST. • 70 k cycles of TWPD polishing might reach a terminal friction condition for HFST. • A strong linear correlations existed between laboratory and field DFT and MPD. • Aggregate size had significant effects on friction and texture properties of HFST. High friction surface treatment (HFST) is commonly used to improve surface friction of asphalt pavements at high crash rate locations, and the objective of this study is to assess the feasibility of using alternative friction aggregates in HFST. Three-wheel polishing device (TWPD) was used to simulate the actual traffic polishing in the laboratory. Firstly, the texture and friction properties of HFSTs with 12 friction aggregates were characterized using circular track meter (CTM) and dynamic friction tester (DFT) after various TWPD polishing cycles (0 k, 70 k, and 140 k). The laboratory results showed that both DFT60 and mean profile depth (MPD) decreased with TWPD polishing cycles, and the DFT60 and MPD results after 70 k TWPD polishing cycles had no significant difference with those values after 140 k TWPD polishing cycles. In addition, a good linear correlation was observed between DFT60 and MPD. Based on the DFT60 results, two bauxite HFSTs showed the best friction performance, and taconite was found to be a suitable alternative aggregate source for HFST. This study also found that slag, silica, and quartz were not good candidates for HSFT application due to the poor texture and friction properties of the corresponding HFSTs. Based on the laboratory evaluation results, eight friction aggregates were selected to pave the HFST sections at the National Center for Asphalt Technology (NCAT) Test Track, which was subjected to 2.6 million equivalent single axle loads (ESALs) in six months. The CTM, DFT, and lock-wheel skid trailer (LWST) were used to characterize the texture and friction properties of field HFST sections, and both DFT and LWST results showed that the bauxite HFST exhibited better friction performance than the granite and flint HFSTs. In addition, there were good linear correlations existing between laboratory DFT60 and MPD results with the corresponding field measurements. Lastly, the influences of aggregate properties (i.e., particle size, durability, angularity, and shape index) on the texture and friction properties of HFST were investigated. The statistical analysis indicated that particle size had significant effects on the MPD and DFT60 of HFST. Meanwhile, only angularity showed a linear relationship with the MPD results of HFST. [ABSTRACT FROM AUTHOR]

• A model of asphalt microcrack containing healing agents is established. • A short-term aged asphalt model is established. • Models of plant oil and aromatic oil as typical healing agents are established. • A method for analyzing asphalt self-healing rate by diffusion coefficient is proposed. Molecular dynamics is used to simulate the self-healing process of asphalts mixed with a healing agent. Sulfoxide functional groups were introduced into the virgin asphalt to produce a short-term-aged asphalt model. The model is validated by comparing density, diffusion coefficient, solubility parameter, and viscosity with real measurements. Plant oil and Aromatic oil are chosen as typical healing agents. The molecular models of asphalt and healing agent are integrated into a micro-crack model, and the healing process is simulated with molecular dynamics. The results show that Plant oil is a better choice for improving the healing rate of virgin asphalt, while Aromatic oil is better for improving the healing rate of short-term-aged asphalt. The higher the temperature is, the better effect the healing agent will have on the asphalt. Healing is maximized above 15 °C for virgin asphalt and above 45 °C for short-term-aged asphalt. Molecular simulations show that the healing process depends on the diffusion of the healing agent and asphalt into the micro-crack. After the crack is filled, bitumen and oil molecules continue to mix. Aromatic oil produces a better mixing that leads to a more uniform composition and better mechanical properties. [ABSTRACT FROM AUTHOR]

• Tracking and observing of the self-healing behavior of asphalt molecules. • Researching the diffusion rate of each component molecule during the self-healing process. • Calculating of the diffusion rates of various molecules of different asphalt MD model. The molecular model of asphalt binder was established by means of molecular dynamics (MD). The MD model was validated with respect of density, glass transition temperature, viscosity and solubility parameters. An interface system was created by inserting a vacuum pad of 50 Å between 2 groups of asphalt binders to study the self-healing behavior of the asphalt binder, e.g. internal volume, diffusion rate of each component and energy variation of the model. The molecular diffusion of aged asphalt binder, SBS modified asphalt binder, and virgin asphalt binder are studied. The results show that the "compression" of asphalt binder volume and the "stretching" of the asphalt binder molecules is responsible for the disappearance of vacuum micro-cracks inside the asphalt binder. When the model volume is "compressed", the volume of the asphalt model decreases until the micro-cracks in the asphalt binder disappear completely. The molecular volume of asphalt decreases greatly at the beginning of the MD simulation, and then becomes stable. The length of asphalt model increases in the OZ direction, while the length of the OX and OY directions decreases, indicating that asphalt "stretces" during the self-healing process. During the self-healing process, the diffusion coefficient of asphaltene molecule is the lowest, while the diffusion coefficient of the saturates is the highest at 360 K, aromatics and resins are close to the average value 6.227 × 10−4 cm2/s in the MD model. Self-healing is mainly based on the Van der Waals forces between non-bonded molecules. The aging of asphalt molecules reduces the diffusion rate of the asphalt model, and the SBS additive indirectly enhances the diffusion rate of asphalt. [ABSTRACT FROM AUTHOR]