Recrystallization in Al-Mn-Cr Alloys

The recrystallization behaviour of pure aluminium and three Al-1wt per cent Mn alloys containing 0.0,0.1 and o.5 per cent Cr as ternary additions has been studied at 90 per cent deformation and at 300 degree centigrade temperatures. It has been observed that Mn and Cr retard the softening process. The presence of 0.1 per cent Cr is useful in lowering the softening rates, whereas o.5 per cent Cr enhances the softening of the alloy. The results are discussed on the basis of the role of precipitate particles and dissolved solute atoms on recrystallization behaviour

Tempering characteristics of a Cu-AI-Ag Alloy

ALUMINIUM- BRONZES , particularly those containing 10 or more of aluminium, have a great potential as future engineering materials. Extensive rescarch is being carried out at present for the development of aluminium - bronzes. Various steps for improving the mechanical properties of these alloys have been recently reviewed.1 One possib-ility is to utilise the effect of ternary elements on mechanical properties and heat treatability of aluminium - bronzes

Tempering Characteristics of A Cu-Al-Ag Alloys

Aluminium bronzes, particularly those containing 10% or more of aluminium, are a very promising system of alloys as future engineering materials. Extensive research is being carried out at present for the development of aluminium bronzes. Various steps for improving the mech-anical properties of these alloys have been recently revi-ewed. One possibility is to utilise the effect of ternary elements on mechanical properties and heat treatability or aluminium bronzes

Why We Read Wikipedia

Wikipedia is one of the most popular sites on the Web, with millions of users relying on it to satisfy a broad range of information needs every day. Although it is crucial to understand what exactly these needs are in order to be able to meet them, little is currently known about why users visit Wikipedia. The goal of this paper is to fill this gap by combining a survey of Wikipedia readers with a log-based analysis of user activity. Based on an initial series of user surveys, we build a taxonomy of Wikipedia use cases along several dimensions, capturing users' motivations to visit Wikipedia, the depth of knowledge they are seeking, and their knowledge of the topic of interest prior to visiting Wikipedia. Then, we quantify the prevalence of these use cases via a large-scale user survey conducted on live Wikipedia with almost 30,000 responses. Our analyses highlight the variety of factors driving users to Wikipedia, such as current events, media coverage of a topic, personal curiosity, work or school assignments, or boredom. Finally, we match survey responses to the respondents' digital traces in Wikipedia's server logs, enabling the discovery of behavioral patterns associated with specific use cases. For instance, we observe long and fast-paced page sequences across topics for users who are bored or exploring randomly, whereas those using Wikipedia for work or school spend more time on individual articles focused on topics such as science. Our findings advance our understanding of reader motivations and behavior on Wikipedia and can have implications for developers aiming to improve Wikipedia's user experience, editors striving to cater to their readers' needs, third-party services (such as search engines) providing access to Wikipedia content, and researchers aiming to build tools such as recommendation engines.Comment: Published in WWW'17; v2 fixes caption of Table

Fractional diffusion modeling of ion channel gating

An anomalous diffusion model for ion channel gating is put forward. This scheme is able to describe non-exponential, power-law like distributions of residence time intervals in several types of ion channels. Our method presents a generalization of the discrete diffusion model by Millhauser, Salpeter and Oswald [Proc. Natl. Acad. Sci. USA 85, 1503 (1988)] to the case of a continuous, anomalous slow conformational diffusion. The corresponding generalization is derived from a continuous time random walk composed of nearest neighbor jumps which in the scaling limit results in a fractional diffusion equation. The studied model contains three parameters only: the mean residence time, a characteristic time of conformational diffusion, and the index of subdiffusion. A tractable analytical expression for the characteristic function of the residence time distribution is obtained. In the limiting case of normal diffusion, our prior findings [Proc. Natl. Acad. Sci. USA 99, 3552 (2002)] are reproduced. Depending on the chosen parameters, the fractional diffusion model exhibits a very rich behavior of the residence time distribution with different characteristic time-regimes. Moreover, the corresponding autocorrelation function of conductance fluctuations displays nontrivial features. Our theoretical model is in good agreement with experimental data for large conductance potassium ion channels

Using Synchronization for Prediction of High-Dimensional Chaotic Dynamics

We experimentally observe the nonlinear dynamics of an optoelectronic time-delayed feedback loop designed for chaotic communication using commercial fiber optic links, and we simulate the system using delay differential equations. We show that synchronization of a numerical model to experimental measurements provides a new way to assimilate data and forecast the future of this time-delayed high-dimensional system. For this system, which has a feedback time delay of 22 ns, we show that one can predict the time series for up to several delay periods, when the dynamics is about 15 dimensional.Comment: 10 pages, 4 figure

Optimal discrete stopping times for reliability growth tests

Often, the duration of a reliability growth development test is specified in advance and the decision to terminate or continue testing is conducted at discrete time intervals. These features are normally not captured by reliability growth models. This paper adapts a standard reliability growth model to determine the optimal time for which to plan to terminate testing. The underlying stochastic process is developed from an Order Statistic argument with Bayesian inference used to estimate the number of faults within the design and classical inference procedures used to assess the rate of fault detection. Inference procedures within this framework are explored where it is shown the Maximum Likelihood Estimators possess a small bias and converges to the Minimum Variance Unbiased Estimator after few tests for designs with moderate number of faults. It is shown that the Likelihood function can be bimodal when there is conflict between the observed rate of fault detection and the prior distribution describing the number of faults in the design. An illustrative example is provided

Powder Bed Fusion Additive Manufacturing Using Critical Raw Materials: A Review.

The term "critical raw materials" (CRMs) refers to various metals and nonmetals that are crucial to Europe's economic progress. Modern technologies enabling effective use and recyclability of CRMs are in critical demand for the EU industries. The use of CRMs, especially in the fields of biomedicine, aerospace, electric vehicles, and energy applications, is almost irreplaceable. Additive manufacturing (also referred to as 3D printing) is one of the key enabling technologies in the field of manufacturing which underpins the Fourth Industrial Revolution. 3D printing not only suppresses waste but also provides an efficient buy-to-fly ratio and possesses the potential to entirely change supply and distribution chains, significantly reducing costs and revolutionizing all logistics. This review provides comprehensive new insights into CRM-containing materials processed by modern additive manufacturing techniques and outlines the potential for increasing the efficiency of CRMs utilization and reducing the dependence on CRMs through wider industrial incorporation of AM and specifics of powder bed AM methods making them prime candidates for such developments

Development and Ergonomic Evaluation of Manually Operated Weeder for Dry Land Crops

A manually operated weeder for dry land crops was developed and evaluated to find its performance. It was compared with other available weeders namely wheel finger weeder, wheel hoe and conventional weeding by using trench hoe for groundnut crop at four levels of soil moisture content of 13.52, 11.63, 9.52 and 8.04 per cent (db). It was found that the heart rate, oxygen consumption rate and energy consumption rate increases with decrease in soil moisture content for all the treatments. The highest performance index of 3689.74 was obtained with developed weeder at 11.63 per cent moisture content. Lowest plant damage (2.46 to 7.96%) and lower energy consumption rate (8.34 to 40.05 kJ/min) with highest performance index (678.66 to 3689.74) of developed weeder at different soil moisture content proved its superiority over other weeders. Soil moisture of 11.63 per cent was found to be optimum for weeding in groundnut crop and the cost of operation of developed weeder at this soil moisture content was found to be Rupees 244.00 as against Rupees 2450.00 per hectare in conventional method of weeding by using trench hoe