Light-weight wood-magnesium oxychloride cement composite building products made by extrusion

This is the post-print version of the final paper published in Construction and Building Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.Magnesium oxychloride (MOC) cement is a type of non-hydraulic cement with yellowish color in nature and low alkalinity exhibiting many other properties superior to Portland Cement (PC). In this study, light-weight wood–MOC cement composite building products, with sawdust and/or perlite as aggregate, were made through extrusion. Physical, nailing and mechanical properties of these composites were investigated. It was found that the specific dry densities of the wood–MOC cement composites were close to 1.0 and they were nailable like hard natural wood. Their flexural strength decreased as temperature increased. By replacing 50% sawdust in weight by perlite, the composite exhibited less die swell and better performance in resisting high temperature.China Ministry of Science & Technology and the European Commission

On utilization of elliptical rings in assessing cracking tendency of concrete

A new experimental method by utilizing elliptical rings to replace circular rings recommended by ASTM and AASHTO was explored for assessing cracking potential of concrete and other cement-based materials under restrained condition. A series of thin and thick elliptical concrete rings were tested alongside circular ones until cracking. Cracking age, position, and propagation were carefully examined. It is found that thin elliptical rings with appropriate geometry can initiate cracks quicker than circular ones, which is desirable for accelerating the ring test. However, thick elliptical rings seem not to exhibit a desirable geometry effect of accelerating ring test compared with circular ones. There were multiple visible cracks that occurred in an elliptical ring and some cracks were initiated but did not propagate through the ring wall. In comparison, there was only one crack in the circular rings. Finally, the features of multiple cracks in restrained elliptical rings were examined and their impact on interpreting elliptical ring test results was elaborated. © 2014 4th International Conference on the Durability of Concrete Structures

A fracture mechanics-based method for prediction of cracking of circular and elliptical concrete rings under restrained shrinkage

A new experimental method, utilizing elliptical ring specimens, is developed for assessing the likelihood of cracking and cracking age of concrete subject to restrained shrinkage. To investigate the mechanism of this new ring test, a fracture mechanics-based numerical approach is proposed to predict crack initiation in restrained concrete rings by using the R-curve method. It has been found that numerical results accord well with experimental results in terms of cracking ages for both circular and elliptical concrete rings, indicating that the proposed fracture mechanics-based numerical approach is reliable for analyzing cracking in concrete ring specimens subject to restrained condition.UK Engineering and Physical Sciences Research Council under the grant of EP/I031952/1, and the National Natural Science Foundation of China under the grant of NSFC 51121005/5110902

Putting culture under the spotlight reveals universal information use for face recognition

Background: Eye movement strategies employed by humans to identify conspecifics are not universal. Westerners predominantly fixate the eyes during face recognition, whereas Easterners more the nose region, yet recognition accuracy is comparable. However, natural fixations do not unequivocally represent information extraction. So the question of whether humans universally use identical facial information to recognize faces remains unresolved. Methodology/Principal Findings: We monitored eye movements during face recognition of Western Caucasian (WC) and East Asian (EA) observers with a novel technique in face recognition that parametrically restricts information outside central vision. We used ‘Spotlights’ with Gaussian apertures of 2°, 5° or 8° dynamically centered on observers’ fixations. Strikingly, in constrained Spotlight conditions (2°, 5°) observers of both cultures actively fixated the same facial information: the eyes and mouth. When information from both eyes and mouth was simultaneously available when fixating the nose (8°), as expected EA observers shifted their fixations towards this region. Conclusions/Significance: Social experience and cultural factors shape the strategies used to extract information from faces, but these results suggest that external forces do not modulate information use. Human beings rely on identical facial information to recognize conspecifics, a universal law that might be dictated by the evolutionary constraints of nature and not nurture

Arc-cathode interaction study

Insufficient electrode life and uncertainties in that life are major problems hampering the development in many plasma application areas which make use of plasma torches, arc heaters, and arc jet thrusters. In spite of a considerable amount of work published dealing with arc-cathode phenomena, our present understanding is still incomplete because different physical phenomena dominate for different combinations of experimental parameters. The objective of our present research project is to gain a better understanding of the behavior of arc-cathode surface interaction over a wide range of parameters, and furthermore to develop guidelines for better thermal design of the electrode and the selection of materials. This report will present the research results and progress obtained on the arc-cathode interaction studies at the University of Minnesota. It includes results which have been obtained under programs other than the NASA funded program. Some of the results have been submitted in an informal interim progress report, and all of the results have been presented in a seminar during a visit to the NASA Lewis Research Center on October 16, 1992

Outage Probability of Wireless Ad Hoc Networks with Cooperative Relaying

In this paper, we analyze the performance of cooperative transmissions in wireless ad hoc networks with random node locations. According to a contention probability for message transmission, each source node can either transmits its own message signal or acts as a potential relay for others. Hence, each destination node can potentially receive two copies of the message signal, one from the direct link and the other from the relay link. Taking the random node locations and interference into account, we derive closed-form expressions for the outage probability with different combining schemes at the destination nodes. In particular, the outage performance of optimal combining, maximum ratio combining, and selection combining strategies are studied and quantified.Comment: 7 pages; IEEE Globecom 201

Causality between Openness and Indigenous Factors among World Economies

The paper studies the causality relationship between economic openness and indigenous factors. The construction of the Openness Index and the Indigenous Index provides a measure on the extent of openness and indigenous development among world economies. The two indices are used to study their causality. The empirical findings show that there are bi-directional dynamic causality relationships between openness and indigenous factors. Indigenous factors help to forecast openness factors and vice versa.Openness, indigeneity, panel data model, causality test