The treatment of uncertainty in knowledge-based systems using fuzzy sets and possibility theory

Knowledge representation issues related to the modelling of imprecision and uncertainty are discussed in the framework of possibility theory. Differences and relations between possibility theory, fuzzy sets, probability theory and Shafer evidence theory are presented. Then, patterns of reasoning and inference and control procedures are studied in presence of uncertainty and imprecision using a possibilistic approach. the basic ideas and the main trends are emphasized rather than the mathematical and logical foundations or the technical details of implementation which can be found in the references.     

An investigation of carbon nanotube jet grinding

Since their observation in 1976 and 1991, carbon nanotubes (CNTs) have generated much interest due to their properties and potential applications. CNTs are tubular carbon molecules with remarkable mechanical, electrical, chemical and thermal properties, which make them useful in various applications. Industries producing CNTs via the fluidized bed chemical vapor deposition technique face challenges related to the size of CNT bundles. The two main challenges are agglomeration and agglomerate size distribution control. A solution to these challenges involves the use of jet mills to grind the CNT agglomerates. The goal of this study was to determine whether the nanotubes could be ground with air jets using a commercial jet mill and apply a two-parameter model to describe the grinding process. The present study has indicated that air-jet grinding of CNTs is feasible with a typical commercial jet mill. This paper presents the effect of operational parameters on the arithmetic mean diameter of the ground product. Sonic velocity through the grinding nozzles was required to obtain reasonable grinding rates and relatively narrow particle size distributions. This occurs at high air to solids feedrate ratios. Additionally, a simple attrition model can describe the grinding process in the spiral jet mill.     

Electron spectroscopies and their use for materials characterization

We present here a general overview of electron spectroscopies from a practical point of view. The most frequently used ones are described and the type of structural information they can provide on materials is explained in relation to the physical processes on which they are based. Furthermore, we explore critically and in detail various tools that have been developed to allow a systematic solving of structures by these spectroscopies.     

SMC composites waste management as reinforcing fillers in polypropylene by combination of mechanical and chemical recycling processes

A new process of management of waste of composite materials from Sheet Moulding Compounds (SMC), as reinforcing fillers for thermoplastic materials, including both mechanical and chemical processes is proposed in this paper. Communited SMC being composed of coated glass fibres intimately mixed with calcium carbonate powder, their reinforcing power is low. First, the fibrous part was increased by partial dissolution of calcium carbonate present in the crushed products SMC. Second, a process of partial solvolysis was developed aiming at strong increasing the interfacial mechanical properties by functionalising of SMC load incorporated into polypropylene/grafted maleic anhydride polypropylene (PP/PP_gma). At this effect, we investigated a treatment with a hot triamine (diethylenetriamine, DETA) in order to create a functionalisation, after scission of the bond ester of unsaturated polyester, as bridging amino-succinimide.The effect of this recycling way by partial solvolysis was checked from the mechanical properties of the resulting reinforced PP/PP_gma material: Although a lower of Young modulus, better yield stress and especially resilience were observed.     

Alpha olefin sulfonates from a commercial SO3-Air reactor

Alpha olefin sulfonate (AOS) can be made by SO₃-air sulfonation of straight chain alpha olefins followed by saponification of the neutralized product. The sulfonation step forms unsaturated sulfonic acids, sultones and sultone sulfonic acids. Hydrolysis of the various sultones yields a mixture of unsaturated and hydroxy sulfonates. Sulfonation of commercial mixtures of straight chain alpha olefins in a large-scale SO₃ falling film unit has given AOS of 1.5–3.0% oil based on active content and tristimulus color of about 40% saturation (2% solution) which is readily bleachable with 1–3% NaOCl to about 10–15% saturation. Performance of AOS made from C₁₅−C₁₈ alpha olefin is comparable to that of the high-foaming C₁₁−C₁₄ LAS in both detergency and dishwashing foam. It is superior to similar products made from internal straight chain olefins. The product shows a low order of toxicity and biodegrad-ability slightly better than that of LAS. A C₁₅−C₁₆ AOS blend is especially attractive in liquid detergent formulations. Presented at the AOCS Meeting, Los Angeles, April 1966.     

Improving the heat transfer of nanofluids and nanolubricants with carbon nanotubes

Low thermal conductivity is a primary limitation in the development of energyefficient heat transfer fluids required in many industrial and commercial applications. To overcome this limitation, a new class of heat transfer fluids was developed by suspending nanoparticles and carbon nanotubes in these fluids. The resulting heat transfer nanofluids and nanolubricants possess significantly higher thermal conductivity compared to unfilled liquids. Three types of heat transfer nanofluids and nanolubricants, each containing controlled fractions of single-wall carbon nanotubes, multiwall carbon nanotubes, vapor grown carbon fibers, and amorphous carbon have been developed for multifunctional applications, based on their enhanced heat transfer and lubricity properties. For more information, contact F.D.S. Marquis, South Dakota School of Mines and Technology, Department of Materials and Metallurgical Engineering, Rapid City, SD 57701; (605) 394-1283; fax (605) 394-3369; e-mail fernand.marquis@sdsmt.edu.     

The use of CFD modelling to optimise measurement of overflow rates in a downstream-controlled dual-overflow structure

The measurement of the flow through complex combined sewer overflow structures in the frame of automated monitoring remains difficult. In this paper, a methodology based on the use of computational fluid dynamics (CFD) modelling in order to improve the instrumentation of a downstream-controlled dual-overflow structure is presented. The dual-overflow structure is composed of two combined sewer overflows (CSOs) connected by a rectangular channel and controlled by a downstream gate located at the entry of the Meyzieu waste water treatment plant (close to Lyon, France). The analysis of the CFD results provides: (i) a better understanding of the interaction between the two CSOs--that means the hydraulic operation, the hydrodynamic behaviour, the backflow effect--and (ii) an ability to optimise the location of the water depth sensor. The measured water depth is used to assess the overflow rate by means of a numerical relationship. Uncertainties are also assessed.