A generalized knowledge representation system for context sensitive reasoning: Generalized HCPRs System

Context sensitive reasoning (i.e., changing the response of the system with change in state of any kind with respect to time, space, matter, or emotions of the system, user, or environment) is significant in real life decision-making. This is a comparatively unexplored facet of intelligent systems and needs to be looked into depth. The Extended Hierarchical Censored Production Rules (EHCPRs) System is an attempt to assemble, maintain, and employ a massive knowledge base exhibiting the property of inheritance and recognition in its reasoning along with the representation of constraints and defaults, and will facilitate all sort of possible learning schemes. Context sensitivity is addressed in the EHCPRs System that result in Generalized HCPRs (GHCPRs) System and its characteristics are exhibited through sample run of implemented system. With different context of user priorities, the GHCPRs system is shown to behave differently in its decision making.     

Intermetallic Compounds Formed in In-3Ag Solder BGA Packages with ENIG and ImAg Surface Finishes

During the reflow process of In-3Ag solder ball grid array (BGA) packages with electroless nickel immersion gold (ENIG) and immersion silver (ImAg) surface finishes, continuous (Au_0.9Ni_0.1)In₂ and scallop-shaped (Ag_0.9Cu_0.1)In₂ intermetallic layers form at the interfaces of In-3Ag solder with Au/Ni/Cu and Ag/Cu pads, respectively. The (Au_0.9Ni_0.1)In₂ layer breaks into clusters with increases in the aging time and temperature. Aging at 115 °C results in the formation of an additional continuous Ni₁₀In₂₇ layer on the Ni/Cu pads and the migration of (Au_0.9Ni_0.1)In₂ intermetallic clusters into the solder matrix. In contrast, the (Ag_0.9Cu_0.1)In₂ scallops grow into a continuous layer after aging treatment. Accompanying the interfacial reactions, AgIn₂ precipitates in the interior of In-3Ag solder balls and coarsens during aging, causing the ball shear strengths of reflown ENIG (1.18 N) and ImAg (1.11 N)-surface-finished solder joints to decrease gradually. However, the migration of (Au_0.9Ni_0.1)In₂ clusters into the solder matrix of ENIG-surface-finished In-3Ag packages leads to an increase in their ball shear strengths after aging at 115 °C over 300 h. Both the ENIG- and ImAg-surface-finished In-3Ag solder joints, after ball shear tests, have fractured across the solder balls with ductile characteristics.     

A formal approach to automating conceptual structural design,part II: Application to floor framing generation

The function of the structural system in a building is to transfer gravity as well as lateral loads from their points of origin to the ground. Floor framing generation involves providing a path to transfer the gravity loads to the ground through various structural elements in an architectural plan while meeting the requirements imposed by other entities, such as the architect, the mechanical engineer, and the contractor, involved in the design/construct process. In this paper a formal approach for generating floor framing plans for steel office buildings is presented. We describe the knowledge and the reasoning behind a computer system, FFG (floor framing generator), which generates floor framing schemes for steel office buildings that are rectangular in plan and have a single service core. Constraints arising from structural as well as exogenous considerations are enumerated and their effect on framing schemes is identified. We also elaborate on the evaluation mechanism for ranking alternative schemes, in addition to providing details of the computer implementation.     

Conversion of acrylonitrile-based precursors to carbon fibres

The effects of stabilization conditions on the formation of a consolidated carbon fibre structure from two acrylonitrile-based precursor fibres, one containing itaconic acid as comonomer and the other a commercial precursor, have been studied. The progression of changes in elemental composition and properties such as sonic modulus, electrical resistance and density in a continuous, low temperature (1200° C) carbonization process are reported for the first time. A criterion based on attaining a composition dependent critical density in stabilization is proposed for avoiding the formation of a hollow core in carbon fibres processed continuously at reasonably rapid rates. Aspects related to the development of open and closed micropores in the carbon fibre structure and the possible mechanisms for the formation of a hollow core in carbonization are also discussed.     

Alumina supported MoO3: an efficient and recyclable catalyst for selective oxidation of tertiary nitrogen compounds to N-oxides using anhydrous TBHP as oxidant under mild reaction conditions

Alumina-supported MoO₃ was found to be an efficient heterogeneous and recyclable catalyst for the oxidation of tertiary nitrogen compounds to N-oxides in excellent yields using anhydrous t-BuOOH as oxidant under mild reaction conditions.     

Material transfer in polymer-polymer sliding

The transfer of material in sliding between polyethylene films and polytetrafluoroethylene, polyvinyl chloride, polypropylene and polymethyl methacrylate discs and between Mylar films and polyethylene and polyvinyl chloride discs was investigated. Infrared spectroscopy and differential thermal analysis were used to detect the direction of material transfer. The transfer process was studied as a function of sliding time, speed and load. It was found that the transfer occurs under all conditions of rubbing and invariably occurs from a material of low cohesive energy density to one of higher cohesive energy density. The thickness of the layer of material transferred has been estimated as a function of the above sliding variables by quantitative infrared spectroscopy. It is found that the layer thickness increases with sliding speed and time but decreases with load. The effect of this material transfer on the coefficient of friction has also been studied for one combination.     

Effect of doping on TSD relaxation in cellulose acetate films

Thermally stimulated depolarization current (TSDC) studies have been performed on solution grown cellulose acetate films doped with different concentrations of acrylic acid (AA) prepared at the poling temperatures (40–75°C) with poling fields (10–50 kV/cm). The TSDC spectra of pure and AA doped CA films reveal two relaxation peaks at 80°C and 180 ±2°C, having activation energies centred around 0.25 and 0.55 eV. The phenomena of the existence of these current maxima have been analyzed and discussed in terms of the molecular motion of the polar side groups and release of the remaining part of the frozen dipoles by their cooperative motion with adjoining segments of the main polymer chain. The peak currents, released charge and activation energies associated with the peaks are affected by AA doping. The effect of doping with acrylic acid on the discharge current indicates the formation of molecular aggregates     

MHD free convective flow through a porous medium in a rotating fluid

In the paper, the velocity and temperature distributions of an electrically conducting liquid flowing past an infinite vertical porous plate through a porous medium in a rotating frame of reference are analysed for the case when a stron magnetic field is imposed in a direction perpendicular to the free stream and at an angle α to the vertical direction. The. influences of various parameters on the velocity field are discussed.     

Performance testing effort at the ATM Forum: an overview

The Test Working Group of the ATM Forum is developing a specification for performance testing of ATM switches and networks. The emphasis is on the user-perceived frame-level performance. This article explains what is different about this new effort and describes its status