A Mechanistic Design Approach for Graphite Nanoplatelet (GNP) Reinforced Asphalt Mixtures for Low-Temperature Applications

This report explores the application of a discrete computational model for predicting the fracture behavior of asphalt mixtures at low temperatures based on the results of simple laboratory experiments. In this discrete element model, coarse aggregates are explicitly represented by spheres, and these spheres are connected by bonds representing the fine aggregate mixture, a.k.a. FAM, (i.e. asphalt binder with the fine-size aggregates). A literature review examines various methods of computational modeling of asphalt materials, as well as the application of nanomaterials to asphalt materials. Bending beam rheometer (BBR) tests are performed to obtain the mechanical properties of the fine aggregate mixture (FAM) at low temperatures. The computational model is then used to simulate the semi-circular bend (SCB) tests of the mixtures. This study considers both the conventional asphalt materials and graphite nanoplatelet (GNP) reinforced asphalt materials. The comparison between the simulated and experimental results on SCB tests shows that by employing a softening constitutive model of the FAM the discrete element model is capable of predicting the entire load-deflection curve of the SCB specimens. Based on the dimensional analysis, a parametric study is performed to understand the influence of properties of FAM on the predicted behavior of SCB specimens

2-{[3-Methyl-4-(2,2,2-trifluoro­eth­oxy)pyridin-2-yl]methyl­sulfan­yl}-1H-benzimidazole monohydrate

The asymmetric unit of the title compound, C16H14F3N3OS·H2O, contains two independent mol­ecules (A and B) and two water mol­ecules, one of which is disordered over two positions in a 0.790 (8):0.210 (8) ratio. The mol­ecular conformations are close, the benzimidazole mean plane and pyridine ring forming dihedral angles of 1.8 (3) and 0.1 (2)° in mol­ecules A and B, respectively. The water mol­ecules are involved in formation of two independent hydrogen-bonded chains via N—H⋯O and O—H⋯N hydrogen bonds. Chains propagating along the a axis are formed by mol­ecule A and one independent water mol­ecule, while chains propagating along the b axis are formed by mol­ecule B and the other independent water mol­ecule. The crystal packing exhibits π–π inter­actions, as indicated by short distances of 3.607 (3) and 3.701 (3) Å between the centroids of the imidazole and pyridine rings of neighbouring mol­ecules

Structural, stereochemical, and bioactive studies of cembranoids from Chinese soft coral Sarcophyton trocheliophorum

LBK

Correlated States in Strained Twisted Bilayer Graphenes Away from the Magic Angle

Graphene moiré superlattice formed by rotating two graphene sheets can host strongly correlated and topological states when flat bands form at so-called magic angles. Here, we report that, for a twisting angle far away from the magic angle, the heterostrain induced during stacking heterostructures can also create flat bands. Combining a direct visualization of strain effect in twisted bilayer graphene moiré superlattices and transport measurements, features of correlated states appear at "non-magic"angles in twisted bilayer graphene under the heterostrain. Observing correlated states in these "non-standard"conditions can enrich the understanding of the possible origins of the correlated states and widen the freedom in tuning the moiré heterostructures and the scope of exploring the correlated physics in moiré superlattices

Pothole Prevention and Innovative Repair

Pothole repairs continue to be a major maintenance problem for many highway agencies. There is a critical need for finding long-lasting, cost-effective materials and construction technologies for repairing potholes. This research effort investigates critical components associated with pothole formation and pothole repair and proposes solutions to reduce the occurrence of potholes and increase the durability of pothole repairs. The components include investigating and documenting pavement preservation activities, experimental work on traditional repair materials as well as innovative materials and technologies for pothole repairs, stress analysis of pothole repairs to identify whether certain geometric configurations are more beneficial than others, evaluating cost analyses to determine the effectiveness of various repair methods. A number of conclusions and recommendations were made. Potholes are mainly caused by the delayed response to timely fixing common pavement distresses. The state of Minnesota has a number of preservation strategies that are available and have been successfully used. Recommendations are made to improve these strategies using documents made available as part of new Every Day Counts, EDC-4, initiative. Currently, there are no required specifications for patching materials. Mechanical testing can be used to select patching materials based on the estimated durability of the pothole repair, such as short-, medium-, and long-term. A number of new materials and technologies are available for more durable solutions for winter pothole repairs, however, they require additional heat source and are more expensive

Identification of four novel small non-coding RNAs from Xanthomonas campestris pathovar campestris

<p>Abstract</p> <p>Background</p> <p>In bacteria, small non-coding RNAs (sRNAs) have been recognized as important regulators of various cellular processes. Approximately 200 bacterial sRNAs in total have been reported. However, very few sRNAs have been identified from phytopathogenic bacteria.</p> <p>Results</p> <p><it>Xanthomons campestris </it>pathovar <it>campestris </it>(<it>Xcc</it>) is the causal agent of black rot disease of cruciferous crops. In this study, a cDNA library was constructed from the low-molecular weight RNA isolated from the <it>Xcc </it>strain 8004 grown to exponential phase in the minimal medium XVM2. Seven sRNA candidates were obtained by sequencing screen of 2,500 clones from the library and four of them were confirmed to be sRNAs by Northern hybridization, which were named sRNA-<it>Xcc</it>1, sRNA-<it>Xcc</it>2, sRNA-<it>Xcc</it>3, and sRNA-<it>Xcc</it>4. The transcription start and stop sites of these sRNAs were further determined. BLAST analysis revealed that the four sRNAs are novel. Bioinformatics prediction showed that a large number of genes with various known or unknown functions in <it>Xcc </it>8004 are potential targets of sRNA-<it>Xcc</it>1, sRNA-<it>Xcc</it>3 and sRNA-<it>Xcc</it>4. In contrast, only a few genes were predicted to be potential targets of sRNA-<it>Xcc</it>2.</p> <p>Conclusion</p> <p>We have identified four novel sRNAs from <it>Xcc </it>by a large-scale screen. Bioinformatics analysis suggests that they may perform various functions. This work provides the first step toward understanding the role of sRNAs in the molecular mechanisms of <it>Xanthomonas campestris </it>pathogenesis.</p

A space-time domain RBF method for 2D wave equations

In the present study, we demonstrate the feasibility to reveal the numerical solution of the multi-dimensional wave equations. A simple semi-analytical meshless method was proposed to obtain the numerical solution of the wave equation with a newly-proposed space-time radial basis function to enhance the numerical stability. The wave equation was discretized into equivalent algebraic equations. By specifying boundary and initial conditions, the wave propagation in a two-dimensional domain can be virtually reconstructed. Our results exhibit that the semi-analytical meshless method is suitable and efficient for solving multi-dimensional wave equations

Comparative and functional genomics reveals genetic diversity and determinants of host specificity among reference strains and a large collection of Chinese isolates of the phytopathogen Xanthomonas campestris pv. campestris

Construction of a microarray based on the genome of Xanthomonas campestris pv.campestris (Xcc), and its use to analyse 18 other virulent Xcc strains, revealed insights into the genetic diversity and determinants of host specificity of Xcc strains