Automated High Throughput Screening of Fluorescent Imaging Plate Reader (FLIPR) Assays Using Assay Platform™ Integrated with Activity Base for ‘on the fly’ Compound Reconfirmation

Advances in the field of automation have meant hitherto complex manual cell-based assays can now be automated. These improvements have brought significant enhancements in throughput, data fidelity and consistency, and allowed a reallocation of constrained resources.Building upon these improvements, we have linked our automated cell-based screening system, Assay Platform™, to Activity Base (IDBS), a software package designed to automate the analysis of HTS data. Customisation of this package has resulted in software that can identify ‘active’ compounds and re-pick them ‘on the fly’ from the original compound plates for triplicate re-testing without operator intervention.Based on an operator initially defining ‘normal’ parameters for assay activity in Activity Base, combined with an automated quality control software module that checks data fidelity, wells containing ‘active’ compounds can be re-picked and re-tested at the end of an automated screening run. Automating cell-based assays has significantly improved productivity, and, with the synergism of Activity Base, has given us greater power to complete each screening run and report ‘active’ compounds to Chemistry more rapidly. This article presents our approach to the automation of cell-based Fluorescent Imaging Plate Reader (FLIPR) screening together with automated active re-test confirmation using Activity Base.     

PET polymer ablation using excimer laser for nozzle plate application

Abstract

Polyethylene terephthalate (PET) film drilling using a 248 nm excimer laser through photomask projection is presented. The parameter effects of laser fluence, shot number and repetition rate on the processing results are examined. A high quality microhole array with 50 μm thick PET film is fabricated. When the projection process is carried out, the diameter differences in the microhole in the front and back side of PET are observed. This causes a conical shape in the kerf. The formation of this conical shape in terms of the laser process parameters is discussed. The process parameter effects are investigated and characterised to improve the PET microhole laser machining quality.     

Fibre orientation structures and their effect on crack resistance of injection moulded transverse ribbed plate

Abstract

An extensive study of the fibre orientation structures developed in a transverse ribbed plate during injection moulding, and the use of these structures to investigate the effect of local fibre orientation state on crack initiation resistance, is reported. The fibre orientation results for the ribbed plate, measured using large area image analysis system developed at Leeds University, showed that after an initial settling down period, the central core region, where the fibres are aligned perpendicular to the flow direction, decreased in size monotonically, with an associated monotonic increase in the outer shell regions, where the fibres are aligned preferentially along the injection direction. Interestingly, the level of orientation in the two regions remained almost constant: only the proportions of the two regions were found to change with flow length. Across the plate, close to the gate, the central core region was found to have a lens-like shape, while at the other end of the plate the core was thinner and also consistent in thickness across the sample width. The transverse rib was found to cause little disturbance to the fibre orientation of the base plate. The different proportions of the shell and core regions at different locations over the ribbed plate provided an ideal case to test the proposition of Friedrich that the crack resistance of a short fibre reinforced material depends on the number of fibres that are perpendicular to the crack tip. The impact test results gathered in this way confirmed this hypothesis of Friedrich.     

Numerical simulation of welding-induced distortion in thin-walled structures

Abstract

A sequentially coupled thermal stress analysis approach is presented for modelling temperature and distortion profiles resulting from welding thin-walled structures. The material is modelled as thermo-elastic–plastic with isotropic strain hardening. The heat source is modelled as a three-dimensional (3-D) double ellipsoid, and 3-D finite element (FE) models are employed for predicting ensuing distortions. Comparisons between the simulation results and experiments performed for eight weld configurations are presented. The weld configurations include bead-on-plate, butt weld and tee joint welds with varying plate thicknesses. Temperature measurements using thermocouples and an infrared (IR) imaging radiometer are directly compared to the thermal simulations. Likewise, distortions measured directly on the experimental set-ups are compared to the FE distortion predictions. Very good correlation is obtained for temperature as well as distortion predictions between experimental and proposed numerical approaches. Lastly, details of a weld simulation for the rear section of a motorcycle frame are presented.     

Influence of the adhesive thickness and steel plate thickness on the behaviour of strengthened concrete beams

The technique of strengthening concrete structures by epoxy bonding the steel plates to the tension face of the structure has been widely used in civil engineering. In this paper, the surface preparation of the concrete and steel plates is described and then the bonding technique is discussed. The influence of the adhesive thickness and the steel plate thickness on the behaviour of strengthened concrete beam is investigated. Beams with six different thicknesses of adhesive layer and five different thicknesses of steel plate were used in this study. The measured load versus strain curves for both the steel plate and the concrete of the strengthened beam were plotted. The results indicate that the ultimate flexural strength does not increase with increasing thickness of the adhesive. The strain at the first cracks in the concrete is unchanged with increasing adhesive thickness. However, at higher loads, the strain in the plate, as well as in the concrete, increased with increasing adhesive thickness. The strain in the steel plate increased at the same rate as that in the concrete in the elastic region and then the strain in the steel plate increased at a much faster rate for the same beam. The results also indicate that the strain corresponding to the ultimate load in the steel plate decreased with increasing plate thickness. The stiffness of the beam increased with the plate thickness, especially in the higher load range.     

Electrodeposition,characterisation and mathematical model of nickel–iron film in a parallel plate flow system

Abstract

Nickel–Iron alloy films were electrodeposited in a parallel plate flow system. The volumetric flow rate of electrolyte was fixed at 12 dm³ min^?1 through the 1 cm thick and 9 cm wide slit parallel plate. Fluid velocity was ca 0.22 m s^?1 under fully turbulent convective flow. Alloy films with iron content varying from 7·5 to 40 wt-% were deposited as a function of solution pH, temperature, bath ingredient concentration and applied current density. It is shown that the magnetic property is strongly correlated to the alloy content: the saturation moment, B _s, increases with the iron composition, while the coercivity, H _c, increases with nickel content. Current efficiency increases with pH and applied current density. The nickel deposition rate is inhibited in the presence of ferrous ion in the plating bath. The microhardness of the deposit is increased as the iron content is increased over the range studied. A mathematical model that considers the convective mass transfer of Fe(II) and Ni(II) species in the diffusion layer, the competition of adsorbed metal species on surface active sites, and Tafel electrochemical kinetics describe the alloy plating system well.     

Determination of dynamic contact angles in solid–liquid–liquid systems using the Wilhelmy plate apparatus

The purpose of this work was to carry out a systematic study of the effects of brine composition and rock mineralogy on rock-oil-brine interactions taking place in petroleum reservoirs. These terms are generally lumped into a single term called wettability in petroleum engineering. The extent of wetting of the rock surface by water or oil depends on the dynamic contact angles measured in such a mode as to enable movements of the three-phase contact line. The Wilhelmy plate technique has been used in this study to measure adhesion tension (which is the product of interfacial tension and cosine of the contact angle) at the solid-liquid interface. The water-advancing and water-receding contact angles have been calculated from the adhesion tensions by making independent measurements of the liquid-liquid interfacial tensions using a du Noüy ring tensiometer. The water-advancing and receding angles have been measured in this study for pure hydrocarbons against synthetic brines of different concentrations. Polished surfaces of glass slides and dolomite have been used to simulate the reservoir rock surfaces. A nonionic surfactant (ethoxy alcohol), which is being used in Yates reservoir in West Texas for enhancing oil recovery, was used to quantify its wettability effects. The results of the systematic experimental investigation of the effects of practical variables on wettability are presented. It is found that interactions between surface-active agents at the interface of two liquids have an effect on wettability alteration. The composition and concentrations of different organic and inorganic chemical species have a major effect in making a reservoir oil-wet or water-wet.     

Thermorheological studies of novel thermoplastic elastomeric blends of nitrile rubber (NBR) and scrap computer plastics (SCP) based on acrylonitrile–butadiene–styrene terpolymer (ABS)

Abstract

Thermorheological properties of thermoplastic elastomeric 60/40, 70/30 and 80/20 nitrile rubber (NBR)/scrap computer plastics (SCP) blends were studied by using parallel plate rheometer. The blends exhibit pseudoplasticity and obey power law model. The dynamically vulcanised blends have higher dynamic viscosities than their unvulcanised counterparts. Surface finish and die swell of the extrudates are improved upon dynamic vulcanisation. The thermoplastic elastomeric blends of NBR/SCP exhibit 'thermorheological complexity'.     

Laser welding of AA 5083 samples by high power diode laser

Abstract

Laser welding is a very attractive technique to join different alloys at the industrial level, due to its low heat input, high flexibility, high weld quality and high production rate. In this work, the weldability of the aluminium alloy AA 5083 with a high power diode laser has been tested. Concisely, samples were subjected to lineal treatments of laser radiation, with the objective of studying the properties of the bead on plate welds generated. The main objective of the present work has been to study the influence of both the processing rate and the superficial treatment of the AA 5083 samples, on the morphological, microstructural and corrosion properties of the laser weld beads. The sizes of the welds were higher as the processing rate was decreased. The weld beads were seen to have better behaviour against corrosion than the base metal due to the microstructural refinement. It was also verified that a blasting process before processing gave beads with lower size but better corrosion resistance than the application of a black layer, due to the minimisation of the magnesium evaporation in this former superficial treatment.     

Effect of inverted pressurisation profile on deformation characteristics of 5083 aluminium alloy during superplastic forming

Abstract

Decreasing the cycle time for superplastic forming of a commercially available superplastic 5083 aluminium alloy has been studied in the present work by use of an inverted pressurisation profile. A right cylindrical cup with a depth/ diameter ratio of 0·5 could be superplastically gas pressure formed in less than 100 s. The deformation behaviour was similar to that of constant strain forming during the free bulging stage. In this stage, a stress state gradient from the pole to the edge of the formed dome was observed. Plasticity controlled growth of cavities was thought to be the mechanism for the increase of cavity volume fraction during forming. After the centre point of the deformed sheet touched the die surface, the metal flow pattern was found to be different from that of the traditional approach. The minimum thickness was not located at around the bottom corner of the cylindrical cup rather it was located ~ 7.5 mm away from the bottom centre of the cup with radius 20 mm. Significant cavity nucleation and coalescence caused higher cavity growth rates at large strains, owing to the continuous increase in strain rate resulting from the imposed pressurisation profile.