Design Processing of Regular and Nonstandard Structural Components

A design standard can be complemented with a case base of nonstandard designs to form a richer knowledge source that can be used in the development of a system for processing of both regular and nonstandard structural designs. This leads to the question of classification of a design context to regular or nonstandard, which relates to the interpretation of the standards scope. This paper describes a software system, called SADA-II, which has been developed to address the issues of standards scope characterization and nonstandard component design processing. SADA-II also introduces a method for processing of standards provisions that are written in a generic format (e.g., pertaining to different section shapes) and explores the potential of integrating the system with a graphics package and other CAD applications. Illustrative examples for the application of SADA-II to detail structural design are provided.     

Diminished regional cerebral blood flow response to vibration in patients with blepharospasm

Mutations of the human Patched gene ( PTCH ) have been identified in individuals with the nevoid basal cell carcinoma syndrome (NBCCS) as well as in sporadic basal cell carcinomas and medulloblastomas. We have isolated a homologue of this tumour suppressor gene and localized it to the short arm of chromosome 1 (1p32.1-32.3). Patched 2 ( PTCH2 ) comprises 22 coding exons and spans approximately 15 kb of genomic DNA. The gene encodes a 1203 amino acid putative transmembrane protein which is highly homologous to the PTCH product. We have characterized the genomic structure of PTCH2 and have used single-stranded conformational polymorphism analysis to search for mutations in PTCH2 in NBCCS patients, basal cell carcinomas and in medulloblastomas. To date, we have identified one truncating mutation in a medulloblastoma and a change in a splice donor site in a basal cell carcinoma, suggesting that the gene plays a role in the development of some tumours.     

Linearised mixer using frequency retranslation

A new linearisation technique using frequency retranslation for generating an error signal to predistort the input of a nonlinear mixer is presented. Results from a two-tone-test at 920 MHz yields a 25 dB reduction in the distortion products and also minimal adjacent channel interference was observed with a π/4 differential quadrature phase shift keying modulated carrier     

Hydrogenation of Low Molecular Weight Polymers in Ionic Liquids and the Effects of Added Salt

The biphasic hydrogenations of a number of polymeric materials, polybutadiene (PBD), nitrile‐butadiene rubber (NBR) and styrene‐butadiene rubber (SBR), were investigated in a toluene/N,N′‐butylmethylimidazolium tetrafluoroborate, (BMI⁺BF₄⁻) system with a water‐soluble analogue of Wilkinson's catalyst, RhCl(TPPTS)₃ (TPPTS=triphenylphosphine, trisulfonated) at 100 °C and 3.1 MPa. The catalyst shows reasonable activity within ionic liquids with PBD although it was necessary in the case of NBR and SBR to add water as a co‐solvent to solubilize the catalyst within the ionic media. Both the extent of hydrogenation and the ratio of the internal 1,4‐olefins to vinyl 1,2‐olefins were monitored. A clear preference for the external olefins was observed even within NBR and SBR where functionalization on the polymer might enhance the degree of hydrogenation of the internal olefins. The effect of adding NaCl to the PBD system was also investigated. The addition of salt decreases the activity of the catalyst but has no effect on the preference for the hydrogenation of vinyl olefins.