Use of Fourier transform infrared spectroscopy to study ageing characteristics of asphalt binders

The present study aims at studying ageing characteristics of conventional bitumen, polymer modified bitumen (PMB) and warm mix asphalt (WMA) by using FTIR. Results of obtained FTIR spectrum were quantified by calculating different indices and finally based on these indices ageing index of the binders for short- and long-term ageing were calculated. Results showed ageing increased amount of complex and high molecular weight components of the binders. PMB was found to have greater ageing resistance than conventional asphalt binders. In case of WMA, results found to be inconclusive, requiring further investigation.     

Generation of Arylated Quinones by Iron‐Catalyzed Oxidative Arylation of Phenols: Formal Synthesis of Phellodonin,Sarcodonin ε, Leucomelone and Betulinan A

Biologically and pharmaceutically relevant arylated quinones (Quin‐Ar) have been synthesized via direct C H arylation of a variety of phenols using arylboronic acids. An inexpensive, environmentally friendly iron catalyst, ferric sulphate, Fe₂(SO₄)₃, was employed in this operationally simple and efficient method.

     

RESHEX: an interactive software package for the synthesis and analysis of resilient heat-exchanger networks—II Discussion of area targeting and network synthesis algorithms

RESHEX is an interactive software package for synthesis and analysis of resilient heat-exchanger networks (HENs). The algorithms used in RESHEX for area targeting and for synthesis of the network structure are described.     

Modelling creep and recovery response of asphalt binders using generalized burgers model

Abstract

Appropriate modeling creep and response of asphalt binders can save time, and resources and efforts required for multiple experimentations. Creep compliance master-curves were obtained from short duration creep experiments on 10 different asphalt binders each at 0.1 and 3.2?kPa stress levels. It was shown that, a four Kelvin-element generalized Burger’s model could closely approximate creep and recovery response at any combination of loading and unloading cycle. A single run of dynamic shear rheometer used for conducting short time creep experiments at different temperatures, can be adequate for modeling creep and recovery response of asphalt binders.     

From scenarios to code: An air traffic control case study

There has been much recent interest in synthesis algorithms that generate finite state machines from scenarios of intended system behavior. One of the uses of such algorithms is in the transition from requirements scenarios to design. Despite much theoretical work on the nature of these algorithms, there has been very little work on applying the algorithms to practical applications. In this paper, we apply the Whittle & Schumann synthesis algorithm [32] to a component of an air traffic advisory system under development at NASA Ames Research Center. We not only apply the algorithm to generate state machine designs from scenarios but also show how to generate code from the generated state machines using existing commercial code generation tools. The results demonstrate the possibility of generating application code directly from scenarios of system behavior.     

Study on viscosity of conventional and polymer modified asphalt binders in steady and dynamic shear domain

This study focuses on evaluating the flow behavior of conventional and polymer modified asphalt binders in steady- and dynamic-shear domain, for a temperature range of 20–70 °C, using a Dynamic Shear Rheometer (DSR). Steady-shear viscosity and frequency sweep tests were carried out on two conventional (VG 10 and VG 30) and two polymer (SBS and EVA) modified asphalt binders. Applicability of the Cox–Merz principle was evaluated and complex viscosity master curves were analyzed at five different reference temperatures. Cross model was used to simulate the complex viscosity master curves at different temperatures.It was found that asphalt binders exhibited shear-thinning behavior at all the test temperatures. The critical shear rate increased with increase in temperature and was found to be lowest for plastomeric modified asphalt binder. The Cox–Merz principle was found to be valid in the zero-shear viscosity (ZSV) domain and deviated at higher frequency/shear rate for all the binders. Results from the study indicated that the ratio of ZSV can be successfully used as shift factors for construction of master curves at different reference temperatures. Cross model was found to be suitable in simulating the complex viscosity master curves at all the test temperatures. Analysis of model parameters indicated that a strong relationship exists between ZSV and the critical shear rate. ZSV and critical shear rate varied exponentially with temperature. This relationship was used to propose a simple equation for assessing the shift factors for construction of master curves.     

Gene sequences of the pcpB gene of pentachlorophenol-degrading Sphingomonas chlorophenolica found in nondegrading bacteria

An optically active, rigid rodlike helical polysilane with 6, 9, 12-trioxatetradecyl and (S)-2-methylbutyl substituents (1) was newly obtained as a very high molecular weight polymer of several million. Due to the presence of trietheral substituent, 1 was readily soluble in a polar solvent such as ethanol and a mixture of ethanol and water, but was insoluble in pure water. Polysilane 1 in pure ethanol at room temperature exhibited an intense and narrow ultraviolet (UV) and circular dichroism (CD) absorptions at 323 nm, associated with an almost mirror imaged fluorescence (FL) at 328 nm, that are characteristics of rigid rodlike, single-screw-sense helical polysilanes reported previously. When solution temperature was changed from 60 degrees C to -104 degrees C, a global shape of 1 expanded associated with an increase of segment length, whereas a screw pitch tended to be wound tightly. On the other hand, as a solvent polarity became poor, a global shape of 1 shrunk associated with an decrease of segment length and formed a chiral motif with an M-helicity between two helical segments with a kink. At a ratio of 50% of ethanol/water of 50:50 (v/v), 1 became insoluble and formed aggregates.     

Graphical control of manufacturing work cells

One vital aspect of the CIM vision is the ever increasing need to control and coordinate the functions of numerous industrial devices within one common manufacturing zone, commonly referred to as a work cell and controlled by one computer. Different industrial devices have different protocols and methods of operation making this task difficult and complex. In addition, the overall logic developed for the coordination of the work cell must be flexible to change for different parts and families, and there must be means to store it for retrieval at a later point in time. The paper describes a software package that provides a generic, graphical interface for manufacturing work cell coordination and control. Developed in C within the CADKEY environment, it allows the user to develop flowcharts for sequencing and coordinating the execution of sub-programs that are collectively responsible for the actual functioning of a work cell. The formulated logic can be used to visualize work cell operation sequences or it can be used to control user-written functions or sub-tasks.     

RESHEX: An interactive software package for the synthesis and analysis of resilient heat-exchanger networks—I Program description and application

RESHEX is an interactive software package for the synthesis and analysis of resilient heat-exchanger networks (HENs). An overview of the program structure, features and functions is presented. A case study describing the revamp of a refinery feed preheat train illustrates the versatility and effectiveness of RESHEX. The case study demonstrates the ease with which a designer can generate (by semi-automatic synthesis and/or evolutionary development) several economically attractive networks which also satisfy practical requirements (such as the revamp network resembling the existing network as much as possible, constraints on the number and location of stream splits and resilience to anticipated changes in operating conditions).

Scope—Over the last decade many techniques for synthesis and analysis of HENs have been developed [e.g. 1–4]. However, the “pencil-and-paper” techniques are awkward for the large-size problems encountered in practical industrial situations, and the “automatized” computer techniques have limited capabilities to accommodate the special requirements of the design engineer. RESHEX is a prototype program where the computer techniques are significantly enhanced in terms of versatility to meet the practical needs of the design engineer. All functions including utility and area targeting, network synthesis, evolutionary network development, resilience analysis and economic optimization are available.

Conclusions and Significance—Figure 2 outlines the typical steps taken by an engineer when designing or revamping an HEN. RESHEX allows these complex needs to be served in a comprehensive manner. The power and versatility of RESHEX is illustrated through a revamp study of a refinery crude preheat train. the revamp study demonstrates the power of RESHEX to allow the engineer to influence the shape of the synthesized network by constraining the number and location of stream splits and exchangers. The study also demonstrates the versatility of RESHEX to suggest what piping changes should be made or where area should be added when revamping the network.