Leaching behaviour of rock material and slag used in road construction ‐ amineralogical interpretation

Rock materials used in road construction contain heavy metal elements bound in minerals that are more or less soluble. There are no requirements for investigations of leaching behaviour before use of rock materials in Sweden, which is the case regarding other materials as, e.g., slags. This implies that there is a lack of data to be used when other materials are evaluated. Seven rock materials and two gravels representing non‐weathered material for use in base or sub‐base course from three counties in Sweden have been investigated regarding mineral composition in order to explain the leaching behaviour. Microscopic studies of the mineral composition, acid‐base‐accounting and pH‐measurements have been used to explain the leaching results achieved with the availability test. The identified transparent minerals were the expected silicate minerals for the sampled rock‐forming materials. Overall, the content of identified opaque minerals was low. How an element is bound in the mineral is decisive for the dissolution of the heavy metal elements. Sulphide bound elements have a notably high fraction that is soluble, especially under oxidising conditions. Chromium and vanadium present as substituted ions in the crystal lattice of oxides are not dissolved. The dissolution of the buffering rock forming silicates is much slower than the dissolution of the acid‐producing sulphides. The results have been compared to similar leaching tests of metallurgical slag used in road construction. The dissolution of the major phase, the solubility of the heavy metal mineral and secondary reactions are factors influencing the dissolved amounts of heavy metal elements. Compared to the crystalline rock materials, the amorphous fuming slag from a copper smelter has very low solubility, while blast furnace slag is easily dissolved due to hydrolysis. The soluble amounts of sulphide bound elements in rock material is higher compared to blast furnace slag. The kinetics of the acid‐producing and acid‐consuming reactions of the rock materials needs to be further investigated. The blast furnace slag and the fuming slag can be used in road construction without any risk of harmful environmental impact due to heavy metal leaching.     

频率源相位噪声对频率步进雷达系统性能的影响

频率源是雷达系统的重要组成部分,其技术指标直接影响系统的性能.文中提出了基于频率源相位噪声的频率步进雷达系统的信号模型,讨论了频率源相位噪声对频率步进雷达系统性能的影响,并得出在满足系统性能的前提下对频率源相位噪声的要求,分析和仿真的结果对系统设计具有一定的指导意义.     

The Future of Simulation: A Field of Dreams

Due to the enormous complexity of computer systems, researchers use simulators to model system behavior and generate quantitative estimates of expected performance. Researchers also use simulators to model and assess the efficacy of future enhancements and novel systems. Arguably the most important tools available to computer architecture researchers, simulators offer a balance of cost, timeliness, and flexibility. Improving the infrastructure, benchmarking, and methodology of simulation - the dominant computer performance evaluation method - results in higher efficiency and let architects gain more insight into processor behavior. For these reasons, architecture researchers have increasingly relied on simulators     

Personality and motivations associated with Facebook use

Facebook is quickly becoming one of the most popular tools for social communication. However, Facebook is somewhat different from other Social Networking Sites as it demonstrates an offline-to-online trend; that is, the majority of Facebook Friends are met offline and then added later. The present research investigated how the Five-Factor Model of personality relates to Facebook use. Despite some expected trends regarding Extraversion and Openness to Experience, results indicated that personality factors were not as influential as previous literature would suggest. The results also indicated that a motivation to communicate was influential in terms of Facebook use. It is suggested that different motivations may be influential in the decision to use tools such as Facebook, especially when individual functions of Facebook are being considered.     

Power System Stability Improvement by Using STATCOM with POC ＆ Excitation Controller

This paper presents the model of a static synchronous condenser （STATCOM） which is controlled externally by a newly designed power oscillation controller （POC） for the improvements of power system stability and damping effect of an on line power system. The proposed POC consists of two controllers （power oscillation damping ＆ proportional integral derivative PID ＆ POD）. PID parameters have been optimized by Zigler Necles close loop tuning method. Machine excitation has been controller by using excitation controller as required. Both single phase and three phase faults has been considered in the research. In this paper, a power system network is considered which is simulated in the phasor simulation method ＆ the network is simulated in three steps： without STATCOM, with STATCOM but no externally controlled, STATCOM with POC. Simulation result shows that without STATCOM, the system parameters become unstable during faults. When STATCOM is imposed in the network, then system parameters become stable. Again, when STATCOM is controlled externally by POC controllers, then system voltage ＆ power becomes stable in faster way then without controller It has been observed that the STATCOM ratings are only 20 MVA with controllers and 200 MVA without controllers. Therefore, STATCOM with POC controllers are more effective to enhance the voltage stability and increases power transmission capacity of a power system. So STATCOM with POC ＆ excitation controllers, the system performance is greatly enhanced.     

Characterization of proteomic changes in cardiac mitochondria in streptozotocin-diabetic rats using iTRAQ™ isobaric tags

Diabetes now affects more than 5% of the world's population and heart failure is the most common cause of death amongst diabetic patients. Accumulating evidence supports a view that myocardial mitochondrial structural and functional changes are central to the onset of diabetic heart failure, but the exact nature of these changes at the proteomic level remains unclear.Here we report on proteomic changes in diabetic rat heart mitochondria following 120 days of streptozotocin‐diabetes using the recently developed iTRAQ? labeling method, which permits quantification of proteins directly from complex mixtures, bypassing the limitations associated with gel‐based methods such as 2‐DE. Of 252 unique proteins identified, 144 were represented in at least three of six individual paired experiments. Relative amounts of 65 proteins differed significantly between the groups, confirming that the cardiac mitochondrial proteome is indeed impacted by diabetes. The most significant changes were increased protein levels of enzymes involved in mitochondrial oxidation of long‐chain fatty acids, which was also confirmed by enzyme assays, and decreased levels of multiple enzymes involved in oxidative phosphorylation and catabolism of short‐chain fatty acids and branched‐chain amino acids. We also found significant changes in levels of several enzymes linked to oxidative stress.     

Synthesis of polyblends from polypropylene and poly(R,S)‐β‐hydroxybutyrate,and their characterization

Blends of modified polypropylene (PP) with poly(R,S)‐β‐hydroxybutyrate (PHB) were prepared by casting polymer solutions, followed by compression molding into thin films. The modified polypropylene was obtained by oxidation with hydrogen peroxide. Oxidation of polypropylene produced new functional groups such as carbonyl and hydroxyl groups on the polymer chain, and a decrease in molecular weight and crystallinity of the polymers. Maximum crystallinity and mechanical properties of the polyblends were found with a PP/PHB ratio of 90/10 (w/w), and then decreased with increasing PHB content in the polyblends. Biodegradability of the polyblends was lower than that of bacterial and synthetic PHBs. Furthermore, an increase of PHB proportion in the polyblends resulted in highly non‐compatible polyblends. Hence only PHB and small parts of the polyblends were decomposed by microorganisms. Copyright © 2006 Society of Chemical Industry     

Treatment of phobic disorders using cognitive and exposure methods: A self-efficacy analysis.

Examined predictions derived from self-efficacy theory in comparing the effects of exposure and cognitive interventions with simple phobics. 22 phobics (25–64 yrs) with fears of either heights, elevators, or darkness were assigned to either guided exposure (GE) or cognitive restructuring (CR) treatments. GE was found significantly superior to CR in enhancing approach behavior, increasing level and strength of self-efficacy, reducing subjective fear, and decreasing physiological reactivity to imagined phobic scenes. High correlations were found between approach behavior and self-efficacy ratings for both groups. GE produced marked improvements in Ss' ability to cope with phobic situations in daily life. CR induced reported improvements in social functioning. At a 1-mo follow-up the results remained much the same. Five additional sessions of GE were then offered to Ss in the CR condition, producing results comparable to those of the original GE group. At a 6-mo follow-up all gains were maintained with further reductions in subjective fear for all GE Ss. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Best of Both Worlds: Synergistically Derived Material Properties via Additive Manufacturing of Nanocomposites

With an exponential rise in the popularity and availability of additive manufacturing (AM), a large focus has been directed toward research in this topic's movement, while trying to distinguish themselves from similar works by simply adding nanomaterials to their process. Though nanomaterials can add impressive properties to nanocomposites (NCs), there are expansive amounts of opportunities that are left unexplored by simply combining AM with NCs without discovering synergistic effects and novel emerging material properties that are not possible by each of these alone. Cooperative, evolving properties of NCs in AM can be investigated at the processing, morphological, and architectural levels. Each of these categories are studied as a function of the amplifying relationship between nanomaterials and AM, with each showing the systematically selected material and method to advance the material performance, explore emergent properties, as well as improve the AM process itself. Innovative, advanced materials are key to faster development cycles in disruptive technologies for bioengineering, defense, and transportation sectors. This is only possible by focusing on synergism and amplification within additive manufacturing of nanocomposites.