Methodology for the development of in-line optical surface measuring instruments with a case study for additive surface finishing

The productivity rate of a manufacturing process is limited by the speed of any measurement processes at the quality control stage. Fast and effective in-line measurements are required to overcome this limitation. Optical instruments are the most promising methods for in-line measurement because they are faster than tactile measurements, able to collect high-density data, can be highly flexible to access complex features and are free from the risk of surface damage. In this paper, a methodology for the development of fast and effective in-line optical measuring instruments for the surfaces of parts with millimetre- to micrometre-size is presented and its implementation demonstrated on an industrial case study in additive manufacturing. Definitions related to in-line measurement and barriers to implementing in-line optical measuring instruments are discussed

Post-Processing of Additively Manufactured Covid-19 Nasopharyngeal Swabs at Scale

A methodology to post-process oral/respiratory Additively Manufactured medical components methods is presented. The system involves PostPro3D® smoothing machine by AMT, picking/racking module, industrial robot, conveyors and is used to smooth the surfaces of Covid-19 Nasopharyngeal Swabs manufactured at-scale using powder-based methods. The presented process for large scale postprocessing of Additively Manufactured articles has undergone all necessary medical verifications and has been already deployed in the field.Mechanical Engineerin

Direct and inverse methods for determining gas flow properties of shale

Gas flow in shale is a poorly understood and potentially complex phenomenon. It is currently being investigated using a variety of techniques including the analysis of transient experiments conducted on full core and crushed shale using a range of gases. A range of gas flow mechanisms may operate including continuum flow, slippage, transitional flow and Knudsen diffusion. These processes as well as gas sorption need to be taken into account when interpreting experimental data and extrapolating the results to the subsurface. A finite volume method is developed in this paper to mathematically model gas flow in shale. The finite volume method combines the efficiency/simplicity of finite difference methods with the geometric flexibility of the finite element approach. The model is applicable to non-linear diffusion problems, in which the permeability and fluid density both depend on the scalar variable, pressure. The governing equation incorporates the Knudsen number, allowing different flow mechanisms to be addressed, as well as the gas adsorption isotherm. The method is validated for unsteady-state problems for which analytical or numerical solutions are available. The method is then applied for solving a pressure-pulse decay test and a comparison with an alternative finite-difference numerical solution is made. An inverse numerical formulation is generated, using a minimisation iterative algorithm, to estimate different number of unknown parameters. Both numerically simulated noisy and experimental data are input into the formulation of the inverse problem. Error analysis is undertaken to investigate the accuracy of results. A good agreement between inverted and exact parameter values is obtained. Results for inversions done for practical laboratory pressure-pulse decay tests of samples with very low permeability are also presented

Finite volume method for modelling gas flow in shale

Gas flow in shale is a complex phenomenon and is currently being investigated using a variety of modelling and experimental approaches. A range of flow mechanisms need to be taken into account when describing gas flow in shale including continuum, slip, transitional flow and Knudsen diffusion. A finite volume method (FVM) is presented to mathematically model these flow mechanisms. The approach incorporates the Knudsen number as well as the gas adsorption isotherm, allowing different flow mechanisms to be taken into account as well as methane sorption on organic matter. The approach is applicable to non-linear diffusion problems, in which the permeability and fluid density both depend on the scalar variable, the pressure. The FVM is fully conservative, as it obeys exact conservation laws in a discrete sense integrated over finite volumes. The method is validated first on unsteady-state problems for which analytical or numerical solutions are available. The approach is then applied for solving pressure-pulse decay tests and a comparison with an alternative finite element numerical solution is made. Results for practical laboratory pressure-pulse decay tests of samples with very low permeability are also presented

Modelling of gas flow in shale using a finite volume method

Gas flow in shale is a very complex phenomenon, currently investigated using a variety of techniques including the analysis of transient experiments conducted on full core and crushed shale using a range of gases. A range of gas flow mechanisms may operate in shale including continuum flow, slippage, transitional flow and Knudsen diffusion. These processes, as well as gas sorption, need to be taken into account when interpreting experimental data and extrapolating the results to the subsurface. Several models have been published that attempt to account for these different processes. Unfortunately, these have a large number of unknown parameters and few studies have assessed the extent to which transient experiments may be used to invert for the key unknowns or the errors that are associated. Here we present a methodology in which various inversion techniques are applied to assess the viability of deriving key unknowns which control gas flow in shale from transient experiments with a range of noise. A finite volume method is developed for solving the model of Civan (2010, 2011a,b) of transient gas flow in shale. The model is applicable to non-linear diffusion problems, in which the permeability and fluid density both depend on the scalar variable, pressure. The governing equation incorporates the Knudsen number, allowing different flow mechanisms to be addressed, as well as the gas adsorption isotherm. The method is verified for unsteady-state problems for which analytical or numerical solutions are available. The method is then applied to a pressure-pulse decay test. An inverse numerical formulation is generated, using a minimisation iterative algorithm, to estimate some unknown physical parameters. Both numerically simulated noisy and experimental data are input into the formulation of the inverse problem. Error analysis is undertaken to investigate the accuracy of results. A good agreement between inverted and exact parameter values is obtained for several parameters. However, it was found that the strong correlation between intrinsic permeability and tortuosity meant that it was not possible to accurately invert simultaneously for these two parameters from the current pressure-pulse decay model

Laboratory characterization of the porosity and permeability of gas shales using the crushed shale method: Insights from experiments and numerical modelling

Gas production from shale resource plays has transformed the USA energy market. Despite the knowledge gained from the analysis of large amounts of shale core, appraisal of shale gas resource plays requires a large number of wells to be drilled and tested. Ideally, core analysis results would provide an indication of both the gas filled porosity and permeability of shale resource plays, which could then be used to reduce the number of wells needed during appraisal. A combination of laboratory experiments, numerical modelling and a round-robin test have been conducted to assess the validity of the crushed shale method (CSM), which has been widely used in industry to assess the porosity and permeability of shale. The results suggest that the CSM can provide reasonably precise estimates of porosity measured at ambient stress if a standard sample cleaning method is adopted; although a reliable method to correct these values to subsurface conditions needs to be developed. The CSM does not, however, appear to provide useful information on shale permeability. A round-robin test shows that differences of up to four orders of magnitude in permeability were provided by different laboratories when analysing the same sample. These huge differences seem to occur due to a combination of errors in calculating permeabilities from pressure transients, differences in the way that permeability is calculated as well as uncertainties regarding the effective size of crushed shale particles. However, even if standardized, the CSM may not be particularly useful for characterizing the flow capacity of shale because it is insensitive to the presence of high permeability zones that would control flow in the subsurface