A Study of the Effect of Blended Coarse Aggregate on Air Entrained Concrete

This research with combined coarse aggregates in cement concrete was initiated at the request of the Director of Design as a direct result of the condition study made by the Division of Design in 1945. In the report on this study it was shown that on the basis of averages pertaining to 80 projects with crashed limestone totalling about 395 miles in length, and 70 projects with Ohio River Gravel totalling approximately 410 miles in length, the service record for pavements with the river gravel was far inferior to that of pavements containing limestone coarse aggregate. Specifically, the summary of data showed that pavements with the gravel had an average of seven times as many outside corner breaks, more than eight times as many inside corner breaks, and almost eleven times as many blow-ups per mile as the pavements with crushed lime stone; furthermore, the average transverse crack and joint interval in the former was only about 0. 6 as long as that in the latter. Such rating was irrespective of age, design, subgrade conditions, separate sources of aggregates, and other factors which in the total analysis were considered individually but which could not be isolated as influences in combination with the coarse aggregates. Naturally, the effect of one or all of these factors could reduce the disparity in performance as related to aggregates alone, nevertheless, the contrast was so pronounced that some measures for obtaining parity of concrete with the different aggregates were considered desirable. As an absolute minimum, research to determine whether results of field observations would be reflected in laboratory tests was proposed. Accordingly, this project was established through an outline or working plan prepared on May 18, 1946. Two corrective measures, air entrainment and blending of aggregates, were the primary bases upon which the research was founded. Results from many investigations - later summarized in a comprehensive report - had indicated that air entrainment had been beneficial to concrete in almost every experiment, and that the greatest improvement in quality of concrete had occurred when the coarse aggregates were inherently of lowest quality. Similarly, blending of aggregates as a means for off-setting detrimental properties of one of the components had been used successfully in other states, an outstanding example of this being in Kansas where aggregates are quite variable and satisfactory sources are far from evenly distributed throughout the state. (A copy of the Supplemental Specification developed in Kansas is appended to this report.) Since air entrainment was due to become a. standard in concrete for pavements, interest was centered on the possible benefits or detriments of combined aggregates and the proportions in which they should be combined in order to provide the best concrete within practicable limits of economy on actual construction jobs

Study of the Effect of Blended Coarse Aggregate on Air Entrained Concrete

This research with combined coarse aggregates in cement concrete was initiated at the request of the Director of Design as a direct result of the condition study made by the Division of Design in 1945. In the report on this study it was shown that on the basis of averages pertaining to 80 projects with crushed limestone totalling about 395 miles in length, and 70 projects with Ohio River Gravel totalling approximately 410 miles in length, the service record for pavements with the river gravel was far inferior to that of pavements containing limestone coarse aggregate. Specifically, the summary of data showed that pavements with the gravel had an average of seven times as many outside corner breaks, more than eight times as many inside corner breaks, and almost elevent time sas many blow-ups per mile as the pavements with crushed limestone; furthermore, the average transverse crack and joint interval in the former was only about 0.6 as long as that in the latter

Machine learning reveals sequence-function relationships in family 7 glycoside hydrolases

Family 7 glycoside hydrolases (GH7) are among the principal enzymes for cellulose degradation in nature and industrially. These enzymes are often bimodular, including a catalytic domain and carbohydrate-binding module (CBM) attached via a flexible linker, and exhibit an active site that binds cello-oligomers of up to ten glucosyl moieties. GH7 cellulases consist of two major subtypes: cellobiohydrolases (CBH) and endoglucanases (EG). Despite the critical importance of GH7 enzymes, there remain gaps in our understanding of how GH7 sequence and structure relate to function. Here, we employed machine learning to gain data-driven insights into relation-ships between sequence, structure, and function across the GH7 family. Machine-learning models, trained only on the number of residues in the active-site loops as features, were able to discriminate GH7 CBHs and EGs with up to 99% ac-curacy, demonstrating that the lengths of loops A4, B2, B3, and B4 strongly correlate with functional subtype across the GH7 family. Classification rules were derived such that specific residues at 42 different sequence positions each predicted the functional subtype with accuracies surpassing 87%. A random forest model trained on residues at 19 positions in the catalytic domain predicted the presence of a CBM with 89.5% accuracy. Our machine learning results recapitulate, as top-performing features, a substantial number of the sequence positions determined by previous experimental studies to play vital roles in GH7 activity. We surmise that the yet-to-be-explored sequence positions among the top-performing features also contribute to GH7 functional variation and may be exploited to understand and manipulate function

Long Range Correlation in Granular Shear Flow II: Theoretical Implications

Numerical simulations are used to test the kinetic theory constitutive relations of inertial granular shear flow. These predictions are shown to be accurate in the dilute regime, where only binary collisions are relevant, but underestimate the measured value in the dense regime, where force networks of size $\xi$ are present. The discrepancy in the dense regime is due to non-collisional forces that we measure directly in our simulations and arise from elastic deformations of the force networks. We model the non-collisional stress by summing over all paths that elastic waves travel through force networks. This results in an analytical theory that successfully predicts the stress tensor over the entire inertial regime without any adjustable parameters

Closing the Nuclear Fuel Cycle with a Simplified Minor Actinide Lanthanide Separation Process (ALSEP) and Additive Manufacturing

Expanded low-carbon baseload power production through the use of nuclear fission can be enabled by recycling long-lived actinide isotopes within the nuclear fuel cycle. This approach provides the benefits of (a) more completely utilizing the energy potential of mined uranium, (b) reducing the footprint of nuclear geological repositories, and (c) reducing the time required for the radiotoxicity of the disposed waste to decrease to the level of uranium ore from one hundred thousand years to a few hundred years. A key step in achieving this goal is the separation of long-lived isotopes of americium (Am) and curium (Cm) for recycle into fast reactors. To achieve this goal, a novel process was successfully demonstrated on a laboratory scale using a bank of 1.25-cm centrifugal contactors, fabricated by additive manufacturing, and a simulant containing the major fission product elements. Americium and Cm were separated from the lanthanides with over 99.9% completion. The sum of the impurities of the Am/Cm product stream using the simulated raffinate was found to be 3.2 × 10−3 g/L. The process performance was validated using a genuine high burnup used nuclear fuel raffinate in a batch regime. Separation factors of nearly 100 for 154Eu over 241Am were achieved. All these results indicate the process scalability to an engineering scale

Anodal Contralesional tDCS Enhances CST Excitability Bilaterally in an Adolescent with Hemiparetic Cerebral Palsy: A Brief Report

Hemiparetic cerebral palsy (HCP), weakness on one side of the body typically caused by perinatal stroke, is characterized by lifelong motor impairments related to alterations in the corticospinal tract (CST). CST reorganization could be a useful biomarker to guide applications of neuromodulatory interventions, such as transcranial direct current stimulation (tDCS), to improve effectiveness of rehabilitation therapies. We evaluated an adolescent with HCP and CST reorganization who demonstrated persistent heightened CST excitability in both upper limbs following anodal contralesional tDCS. Results support further investigation of targeted tDCS as an adjuvant therapy to traditional neurorehabilitation for upper limb function

The Intrinsic Absorber in QSO 2359-1241: Keck and HST Observations

We present detailed analyses of the absorption spectrum seen in QSO 2359-1241 (NVSS J235953-124148). Keck HIRES data reveal absorption from twenty transitions arising from: He I, Mg I, Mg II, Ca II, and Fe II. HST data show broad absorption lines (BALs) from Al III 1857, C IV 1549, Si IV 1397, and N V 1240. Absorption from excited Fe II states constrains the temperature of the absorber to 2000K < T < 10,000K and puts a lower limit of 10^5 cm^{-3} on the electron number density. Saturation diagnostics show that the real column densities of He I and Fe II can be determined, allowing to derive meaningful constraints on the ionization equilibrium and abundances in the flow. The ionization parameter is constrained by the iron, helium and magnesium data to -3.0 < log(U) < -2.5 and the observed column densities can be reproduced without assuming departure from solar abundances. From comparison of the He I and Fe II absorption features we infer that the outflow seen in QSO 2359-1241 is not shielded by a hydrogen ionization front and therefore that the existence of low-ionization species in the outflow (e.g., Mg II, Al III, Fe II) does not necessitate the existence of such a front. We find that the velocity width of the absorption systematically increases as a function of ionization and to a lesser extent with abundance. Complementary analyses of the radio and polarization properties of the object are discussed in a companion paper (Brotherton et al. 2000).Comment: 30 pages, 9 figures, in press with the Ap

Wikipedia as an encyclopaedia of life

In his 2003 essay E O Wilson outlined his vision for an &#x201c;encyclopaedia of life&#x201d; comprising &#x201c;an electronic page for each species of organism on Earth&#x201d;, each page containing &#x201c;the scientific name of the species, a pictorial or genomic presentation of the primary type specimen on which its name is based, and a summary of its diagnostic traits.&#x201d; Although the &#x201c;quiet revolution&#x201d; in biodiversity informatics has generated numerous online resources, including some directly inspired by Wilson&#x27;s essay (e.g., &#x22;http://ispecies.org&#x22;:http://ispecies.org, &#x22;http://www.eol.org&#x22;:http://www.eol.org), we are still some way from the goal of having available online all relevant information about a species, such as its taxonomy, evolutionary history, genomics, morphology, ecology, and behaviour. While the biodiversity community has been developing a plethora of databases, some with overlapping goals and duplicated content, Wikipedia has been slowly growing to the point where it now has over 100,000 pages on biological taxa. My goal in this essay is to explore the idea that, largely independent of the efforts of biodiversity informatics and well-funded international efforts, Wikipedia (&#x22;http://en.wikipedia.org/wiki/Main_Page&#x22;:http://en.wikipedia.org/wiki/Main_Page) has emerged as potentially the best platform for fulfilling E O Wilson&#x2019;s vision