Deliberately Losing Control of C−H Activation Processes in the Design of Small-Molecule-Fragment Arrays Targeting Peroxisomal Metabolism

Combined photochemical arylation, “nuisance effect” (S_NAr) reaction sequences have been employed in the design of small arrays for immediate deployment in medium-throughput X-ray protein–ligand structure determination. Reactions were deliberately allowed to run “out of control” in terms of selectivity; for example the ortho-arylation of 2-phenylpyridine gave five products resulting from mono- and bisarylations combined with S_NAr processes. As a result, a number of crystallographic hits against NUDT7, a key peroxisomal CoA ester hydrolase, have been identified.     

Product mix determination in the presence of alternate process plans and stochastic demand

The product mix problem in the presence of alternate process plans under uncertain demand is formulated as a non-linear programming model. A heuristic solution procedure based on lagrangean relaxation technique is also presented.     

Multi-grid domain decomposition approach for solution of Navier–Stokes equations in primitive variable form

A new multi-grid (two-grid) pseudospectral element method has been carried out for solution of incompressible flow in terms of primitive variable formulation. The main objective of the proposed method is to apply the multi-grid technique solving the incompressible flow problems associated with three commonly encountered multi-grid environments. In domain decomposition terminology, it includes (I) partially overlapped subdomains, each of which has same types of grids; (II) partially overlapped subdomains, each of which has different types of grids; (III) local adaptive subdomains fully overlapped with the original computational domain (composite grids). The approach for flow problems, complex geometry or not, is to first divide the computational domain into a number of subdomains with the inter-overlapping area (partially or fully overlapped). In categories I and II, the fine-grid or coarse-grid subdomains can be defined by their representation, while in category III the fine-grid or coarse-grid subdomains are defined as usual. Next, implement the Schwarz Alternating Procedure (SAP) to exchange the data among subdomains, where the coarse-grid correction is used to remove the high frequency error that occurs when the data interpolation from the fine-grid subdomain to the coarse-grid subdomain is conducted. The strategy behind the coarse-grid correction is to adopt the operator of the divergence of velocity field, which intrinsically links the pressure equation, into this process. The solution of each subdomain can be efficiently solved by the direct (or iterative) eigenfunction expansion technique or preconditioned method with the least storage requirement, i.e. O(N²) in 2-D. Numerical results of (i) driven cavity flow (Re = 100,400) with Cartesian grids (category I) in each subdomain, (ii) driven cavity flow (Re = 3200) with local adaptive grids (category III) in each subdomain, and (iii) flow over a cylinder (Re = 250) with ‘O’ grids in one subdomain and Cartesian grids in another (category II) will be presented in the paper to account for the versatility of the proposed multi-grid method.     

APPLICATION OF RESPONSE SURFACE METHODOLOGY FOR THE MAXIMIZATION OF CONCORA CRUSH RESISTANCE OF PAPERBOARD

Response surface methodology is often used by researchers in different fields to determine the optimum values for controlled variables to maximize or minimize the response variables. Either maximization or minimization might be necessary depending on the response property. For example, if the response variable represents the yield of a process, maximization could be necessary; on the other hand, if the response variable is the biological oxygen demand (BOD) of an effluent the aim would definitely be minimization

Response surface methodology can be used two ways. It can be applied to the full-scale production or it can be scaled to a laboratory or the pilot plant. When applied to the full-scale production, the method is known as evolutionary operation (EVOP). EVOP is the continuous optimization of a process. The optimum conditions in a production plant can change depending on many factors such as raw material, ambient temperature, and equipment wear. Therefore, controlled variables should be optimized continuously to keep the response variable as close as possible to the maximum or minimum value. Hence, controlled variables are systematically changed around a center point to depict any shift of the response variable from the extreme. A thorough discussion of EVOP is given by Box, Evolutionary Operation: A Method for Increasing Industrial Productivity, Appl. Statist., 6, 81-101 (1957).     

Dyes from the leaves of deciduous plants with a high tannin content for wool

The aqueous leaf extracts of five different deciduous plants, namely, silver oak, flame of the forest, tanner’s senna, wattle and serviceberry, were used on their own and in combination with aluminium sulphate, stannous chloride and ferrous sulphate to dye wool by a simultaneous mordanting technique. The washing and light fastness properties of the developed shades were moderate to good. Based on the CIE 2000 spectral colour coordinate values (K/S, ΔL, Δa, Δb and ΔE), the developed shades were classified into four groups: yellow/brown, yellow, orange and dark grey. The use of aluminium sulphate gave medium shades (K/S = 8.24), while the stannous chloride and ferrous sulphate mordants provided deep shades (K/S = 30.5). Statistical analyses have shown that only the type of mordant and not the dye source significantly influenced the development of colour on wool. Hence, it was theoretically possible to use five selected leaves as a single mixture to produce four different colours on wool.     

Sliding wear behavior of salt bath nitrocarburized medium carbon steel

Salt bath nitrocarburizing is a well-known thermochemical diffusion process for enhancing the tribological and corrosion properties of ferrous components. The current work describes the role of a compound layer developed during nitrocarburizing, both in the ferritic and austenitic regimes of Fe-N-C system, on the sliding wear behavior of a medium carbon steel. The wear behavior of the nitrocarburized steel discs was assessed by the pin-on-disc tests (ASTM G 99-99) under different normal loads running against a hardened SAE52100 pin. It was observed that the compound layer on the surface not only controlled the wear rate but also resisted the adhesive wear/transfer of material from pin to disc, aside from providing low-friction coefficients.     

Soil–conduit interaction: an artificial intelligence application for reinforced concrete and corrugated steel conduits

Neural Computing and Applications - Marston’s load theory is commonly used for understanding the soil–conduit interaction. However, there are no practical methods available which can...     

Scanning Auger electron spectroscopy study of the oxide film formed on dendritic and interdendritic regions of C containing Fe3Al intermetallic

The oxide films formed during early stage of oxidation at 800 °C on dendritic and interdendritic regions of the cast Fe–16Al–1C (wt.%) alloy were studied using scanning Auger electron spectroscopy. Microhardness measurement and elemental depth profiles by Auger spectroscopy reveal that the carbide, Fe₃AlC_0.69, is the major constituent of the interdendritic region, while dendrites are predominantly Fe₃Al phase. Between the two, the interdendritic region is found to be more prone to oxidation than the dendritic region, which was attributed to presence of carbides with low-Al content. In spite of the difference in oxide film thickness exhibited by both the phases, they consist of an inner aluminium oxide layer and an outer iron oxide layer.     

Compositional trend analysis on poly(phenylene ether) based thermoplastic elastomers

Detailed statistical trend analysis of thermoplastic elastomers based on poly (phenylene ether) (PPE), polystyrene (PS), ethylene vinyl acetate (EVA) and styrene‐ethylene‐butylene‐styrene (SEBS) was done through Design Expert software by Stat‐Ease. D optimal crossed design was followed to capture the interaction with the parameters. Effect of blend ratio, vinyl acetate (VA) content of EVA, molecular weight (MW) of SEBS and intrinsic viscosity (IV) of PPE on the blend performance (response) was studied in detail. Design of Experiment (DOE) analysis showed the “optimized formulation” of the blend. Increase in PPE‐polystyrene (PS) content increased tensile strength and modulus of the blend, followed by a decrease in strain at break. However, EVA had a reverse effect on tensile strength and modulus. Strain at break increased significantly with increasing SEBS content in the blend. Graphical and numerical optimization showed that superior mechanical properties (tensile strength, strain at break and modulus) could be achieved at VA content ～ 50% at a particular loading of EVA. Low MW SEBS was found to be more compatible with the other components of the blend. Mechanical properties of the quaternary blend were marginally affected with change in IV of PPE in the range of 0.33 to 0.46. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007