INNOVATIVE TESTS TO PREDICT THE STRENGTH AND TYPE OF ASPHALT-AGGREGATE BONDS

ABSTRACT

This paper discusses two techniques to characterize the type and measure the strength of asphalt-aggregate bonds. The Modified Lottman Test is commonly used to measure the physical strength of asphalt-aggregate bonds. Under certain conditions bonds may become weak due to chemical factors that are not accounted for in the Modified Lottman Test. In order to measure the chemical strength of the bond, a chemical preconditioning stage was introduced prior to performing the Modified Lottman Test. During this stage a compacted mix pill was exposed to an environment that was rich in either OH^?- or H^plus; ions. Such high or low pH conditions affect bonding reactions that are reversible in nature, and thereby expose the chemical weakness of the bond. Results show that different antistrip agents react differently to such conditions. The paper also discusses the effect of mix curing on bond strength under these limiting pH conditions. The other technique discussed in this paper, U a test that characterizes different aggregates in terms of their reactivity with aspnaltic components, which subsequently helps identify those aggregates that would form strong bonds with asphalt. It was observed that even within limestones aggregates, different types reacted to a different extent, and thereby, could be easily characterized     

Achievable PID performance using sums of squares programming

In addition to process elements like time delay, the PID structure of the controller can pose fundamental limitations on the achievable control performance. A key difficulty in characterizing the limitations due to controller structure is the non-convexity of the resulting optimization problem. In this paper, we present a global lower bound on the achievable PID performance, defined in terms of output variance, by solving a series of convex programs using sums of squares programming. This result is also extended to minimize the weighted sum of the variances of input rate and output. The tightness of the proposed bounds is demonstrated using several benchmark examples drawn from literature.     

Link quality analysis and measurement in wireless mesh networks

Protocols and applications in wireless mesh networks often optimize their performance by measuring the quality of wireless links. However, measuring and characterizing link-quality is a challenging task due to the nature of wireless channel and device-specific properties of radios. The paper proposes two aspects of link-quality measurement and estimation in realistic networks that benefit higher-layer protocols. First, we analyze the statistical properties of link-quality metrics, such as received signal strength and packet error rates, in an indoor IEEE 802.11 mesh network. We show that the statistical distribution and memory properties vary across different links, but are predictable. The next contribution of the paper is a real-time measurement framework that enables higher-level protocols in wireless mesh networks. We discuss the architectural requirements and our implementation experiences of a measurement framework. In addition, we provide three concrete applications that use the measured link-quality and statistical inference to better adapt their behavior.     

Band ordering in compression of ultraspectral images

Atmospheric InfraRed Sounder images are a type of ultraspectral images that are good candidates to compression as they include several thousand bands that account for well over 40 MB of data per single cube. As part of most prediction based compression schemes, there is a preprocessing stage in which a reversible band ordering process is included to maximize spectral band correlation. In this paper, we analyze, compare, and propose novel improvements to different band ordering and correlation estimation techniques in the context of ultraspectral image compression. In order to measure the performance of these methods, we also introduce a new metric based on comparing a given sequence of spectral bands to the corresponding optimal one. Finally, we apply the techniques presented in this paper to a real compression algorithm in order to obtain compression rates as a function of band ordering and correlation factors while determining the best scenario.     

Systems analysis of a multi-stage tubular module reverse osmosis plant for sea water desalination

A tubular reverse osmosis system for sea water has been analyzed based on current cellulose acetate membrane technology. The possibility of staging product water in two and three stages has been studied. A dynamic programming model is developed and solved to arrive at optimum operating parameters for the two-stage and three-stage designs.A variable membrane permeability model is used to simulate operating conditions along the tube length within a stage, to arrive at optimum membrane curing temperatures. Actual performance data from UCLA's experimental plant at La Jolla, California was used. Cost analysis and equations are derived from actual costs incurred at La Jolla.     

Theoretical hydrodynamic load capacity of an axially undefined full porous journal bearing in the turbulent regime considering slip flow and curvature

A mathematical analysis using a new generalized pressure equation is reported for the hydrodynamic lubrication of a 360° long porous metal journal bearing with arbitrary wall thickness which is press fitted in a solid housing and works with a turbulent film of newtonian lubricant. The limiting case of an axially undefined length of the bearing is considered and the axial flow of lubricant in the clearance space is neglected so that the governing differential equation is simpler to solve. Half Sommerfeld boundary conditions are used for the extent of the azimuthal film and film curvature has been included. The curvature effect of the thick porous bearing matrix is taken into account by a new direct approach in which the separation of variables is used for the first time in such a problem. The collocation technique is utilized to determine the hydrodynamic pressure from which the characteristics are evaluated. The results are fully analytical in nature, simple, yet exact and accurate, permitting easy and economical calculation of numerical data over a very wide range of parameters.     

Condensation polymers from natural oils

Innovative technologies and competitive industrial products are reducing the dependence on petrochemicals for the production of polymers. Increasing concerns about the deteriorating environment caused by conventional polymers have directed worldwide research toward renewable resources. Vegetable oils are one of the most readily available alternative renewable resources. The functional groups present in natural oils can be activated for condensation polymerization. Accordingly, various types of useful condensation polymers, such as polyurethanes, polyesters and polyethers, are being produced by this route. The incorporation of natural oils into the polymer chain allows tailoring the properties of polyurethane products, for their widespread applications.     

Spectrum of thermal voltage fluctuations in current-driven,small-capacitance Josephson junctions

We have calculated the spectrum of thermally induced voltage fluctuations in a small-capacitance, current-driven Josephson junction, within the resistively shunted model but with no other approximations. We exploit a novel representation of the solution to the initial value problem for the diffusion of the phase to reduce the fluctuation spectrum to integrals. Numerical results are presented.     

Synthesis of biodiesel fuel from safflower oil using various reaction parameters

Biodiesel fuel is gaining more and more importance because of the depletion and uncontrollable prices of fossil fuel resources. The use of vegetable oil and their derivatives as alternatives for diesel fuel is the best answer and as old as Diesel Engine. Chemically biodiesel fuel is the mono alkyl esters of fatty acids derived from renewable feed stocks like vegetable oils and animal fats. Safflower oil contains 75-80% of linoleic acid; the presence of this unsaturated fatty acid is useful in alleviating low temperature properties like pour point, cloud point and cold filter plugging point. In this paper we studied the effect of various parameters such as temperature, molar ratio (oil to alcohol), and concentration of catalyst on synthesis of biodiesel fuel from safflower oil. The better suitable conditions of 1:6 molar ratio (oil to alcohol), 60 degrees C temperature and catalyst concentration of 2% (by wt. of oil) were determined. The finally obtained biodiesel fuel was analyzed for fatty acid composition by GLC and some other properties such as flash point, specific gravity and acid value were also determined. From the results it was clear that the produced biodiesel fuel was with in the recommended standards of biodiesel fuel with 96.8% yield.