Fatigue life of hot mix asphalt mixtures

Fatigue cracking is one of the major types of distress in asphalt concrete pavements. Under the action of repeated vehicular loading, the asphalt concrete deteriorates and eventually results in fatigue cracking. This study investigated the effect of temperature, aggregate gradation, nominal maximum aggregate size, and asphalt types on fatigue life of hot mix asphalt (HMA) mixtures. Six mixtures were selected namely asphaltic concrete with nominal maximum aggregate size of 10 mm (AC10), and 14 mm (AC14), polymer modified asphalt concrete 10 mm (PMA10), and 14 mm (PMA14), and stone mastic asphalt 14 mm (SMA14), and 20 mm (SMA20). Specimens were prepared at optimum asphalt content using the Marshall Mix design procedure. Indirect tensile test for resilient modulus was performed according to ASTM D 4123. Fatigue test was also conducted to determine the performance of the mixtures. The specimens were prepared using 80/100 penetration asphalt for AC10 and AC14, and using PG76 asphalt for PMA10, PMA14, SMA14, and SMA20. Fatigue tests with constant stress were performed using Universal Testing Machine at 25° C and 40° C at a load of 1000 N. The results showed that fatigue life of asphalt mixture was lower at 40° C than that at 25° C. It was also observed that the mixtures with smallest nominal maximum aggregate size had higher fatigue life. The PMAs developed greater fatigue performance than SMAs and ACs, due to aggregate gradation and asphalt type

Fast, Accurate Second Order Methods for Network Optimization

Dual descent methods are commonly used to solve network flow optimization problems, since their implementation can be distributed over the network. These algorithms, however, often exhibit slow convergence rates. Approximate Newton methods which compute descent directions locally have been proposed as alternatives to accelerate the convergence rates of conventional dual descent. The effectiveness of these methods, is limited by the accuracy of such approximations. In this paper, we propose an efficient and accurate distributed second order method for network flow problems. The proposed approach utilizes the sparsity pattern of the dual Hessian to approximate the the Newton direction using a novel distributed solver for symmetric diagonally dominant linear equations. Our solver is based on a distributed implementation of a recent parallel solver of Spielman and Peng (2014). We analyze the properties of the proposed algorithm and show that, similar to conventional Newton methods, superlinear convergence within a neighbor- hood of the optimal value is attained. We finally demonstrate the effectiveness of the approach in a set of experiments on randomly generated networks.Comment: arXiv admin note: text overlap with arXiv:1502.0315

PRODUCT DISASSEMBLABILITY AND REMANUFACTURABILITY ASSESSMENT: A QUANTITATIVE APPROACH

Majority of the products get discarded at end-of-life (EoL), causing environmental pollution, and resulting in a complete loss of all materials and embodied energy. Adopting a closed-loop material flow approach can aid preventing such losses and enable EoL value recovery from these products. Design and engineering decisions made and how products are used impact the capability to implement EOL strategies such as disassembly and remanufacturing. Some underlying factors affecting the capability to implement these EOL strategies have been discussed in previous studies. However, relevant metrics and attributes are not well defined and comprehensive methods to quantitatively evaluate them are lacking. This study will first identify key lifecycle oriented metrics affecting disassemblability and remanufacturability. Then a methodology is proposed for the quantitative evaluation of these strategies considering the quality of returns, product-design characteristics and process technology requirements. Finally, an industrial case-study is presented to demonstrate the application of the proposed method

Design of Secure Chatting Application with End to End Encryption for Android Platform

In this paper, a secure chatting application with end to end encryption for smart phones that used the android OS has beenproposed. This is achieved by the use of public key cryptography techniques. The proposed application used the Elliptic Curve DiffieHellman Key Exchange (ECDH) algorithm to generate the key pair and exchange to produce the shared key that will be used for theencryption of data by symmetric algorithms. The proposed Application allows the users to communicate via text messages, voicemessages and photos. For the text message security the standard AES algorithm with a 128 bit key are used. The generated key (160 bit)minimized to 128 bit length by selecting the first 128 bit of the generated key in order to be used by the AES algorithm. For the voice andimage security processes the proposed application used the symmetric algorithm RC4 for this purpose

In the Shadow of Ghadar: Marxism and Anti-Colonialism in Colonial Punjab

The Ghadr Party, an eclectic group of diasporic Punjabis, was perhaps one of the most significant political movements led by emigre Indians in the early twentieth century. Designated as one of the biggest threats to colonial rule in the 1910s, the Ghadr Party spread its operations over five continents, and repeatedly committed acts of sabotage aimed at colonial officials from India. By the 1920s, however, the birth of popular movements in India marginalized various groups that believed in the spectacular actions of a vanguard as a strategy for overcoming the stifling impact of colonial rule. Members of the party, eager to find a foothold in the changed political scenario, opened discussions for building a popular front in Punjab, with many returning to the country to participate in such an endeavour. In this article, I study the encounter between the Ghadarite tradition and the communist movement in colonial Punjab through the writings of Sohan Singh Josh, who attempted to bring these two traditions together to produce a viable political project. I argue that Ghadar's encounter with Marxism not only influenced the former, but also radically transformed Marxism itself, particularly on questions of History, violence and volition