Tubing specifications selection and its effect on the results of hydraulic fracturing treatment in oil formations

Equipment specification, data collection and design process are critical factors for any hydraulic fracturing treatment success. This paper investigates tubing specifications selection and its effect on the results of hydraulic fracturing treatment in oil formations. Simulations were carried out on well E-45 owned by National Oil Corporation (NOC) of Libya using two main tools - Pumping Diagnostic Analysis Toolkit (PDAT) and Halliburton proprietary software package (FracPro) for analysing Mini-Frac pumping data. The initial modelling results using 3.5 inch tubing were compared with the experimental results obtained from the actual hydraulic fracturing tests carried out at the E45 by Halliburton as a sub-contractor for NOC. The simulation results showed good agreement with the experiments, validating the model. The model was then extended to explore alternate tubing diameters. This was implemented by introducing the relationship between the tub friction pressures and pumping rate (Friction Pressure vs. Pumping Rate) with the mentioned tube sizes. The results showed that in high stress rock formations, it is worthwhile to minimise the pipe friction by using higher tubing grade (4.5 inches) and burst pressure. A bigger tubing inner diameter can increase the allowable surface pumping rate and pressure

Learning based automatic face annotation for arbitrary poses and expressions from frontal images only

Statistical approaches for building non-rigid deformable models, such as the active appearance model (AAM), have enjoyed great popularity in recent years, but typically require tedious manual annotation of training images. In this paper, a learning based approach for the automatic annotation of visually deformable objects from a single annotated frontal image is presented and demonstrated on the example of automatically annotating face images that can be used for building AAMs for fitting and tracking. This approach employs the idea of initially learning the correspondences between landmarks in a frontal image and a set of training images with a face in arbitrary poses. Using this learner, virtual images of unseen faces at any arbitrary pose for which the learner was trained can be reconstructed by predicting the new landmark locations and warping the texture from the frontal image. View-based AAMs are then built from the virtual images and used for automatically annotating unseen images, including images of different facial expressions, at any random pose within the maximum range spanned by the virtually reconstructed images. The approach is experimentally validated by automatically annotating face images from three different databases

Two new records of Plagiothecium from India

Abstract Govind Wild Life Sanctuary in the Western Himalayas with its diverse vegetation types provides excellent habitats and microclimates for a lush growth of bryophytes. During investigations on the bryophytes of this region Plagiothecium euryphyllum (Cardot et Thér.) Z. Iwats. and P. cavifolium (Brid.) Z. Iwats. have been identified for the first time from India. P. euryphyllum is characterised by bright green to yellowish green plants, irregularly branched, complanate. Central strand developed. Leaves erectopatent, imbricate, ovate oblong, margin entire, acute to acuminate at apex, costa two forked, decurrent with hyaline, rectangular cells. Seta reddish, capsule erect to inclined, while plants of P. cavifolium are yellowish green, glossy, prostrate, irregularly branched, branches julaceous. Leaves appressed to stem, closely imbricate, erectopatent, ovate lanceolate, symmetrical, margin minutely dentate at apex, cells at alar region rectangular costa two short. Seta reddish brown, capsule erect, pyriform. A morpho-taxonomic account of above two taxa is provided

REPRESENTATION SCHEMES FOR MATHEMATICAL PROGRAMMING MODELS

Because of the difficulties often experienced in formulating and understanding large scale models, much current research is directed towards developing systems to support the construction and understanding of management science models. This paper discusses seven different methods for representing mathematical programming models during the formulation phase of the modeling process. The approaches discussed are block-schematic, algebraic, three different kinds of graphical schemes, a database-oriented approach and Structured Modeling. We emphasize representations that have graphical elements suitable for incorporation in the interface to a modeling system. The different methods are compared using a common example and the transformations that allow one to go from one representation to another are discussed.Information Systems Working Papers Serie

Vocal cord palsy in an infant with myelomeningocoele

In this article we describe the case of a four-month-old male infant with myelomeningocoele, who presented with inspiratory stridor and vocal cord palsy (VCP). Hindbrain dysfunction is a leading cause of mortality and morbidity in children with neural tube defects. It is important to consider the above in the differential diagnosis of infants with breathing difficulties. A discussion of myelodysplasia, Arnold-Chiari malformations, bilateral VCP and anaesthesia management is presented.South Afr J Anaesth Analg, 2011;17(6):394-39

Neural apparent BRDF fields for multiview photometric stereo

We propose to tackle the multiview photometric stereo problem using an extension of Neural Radiance Fields (NeRFs), conditioned on light source direction. The geometric part of our neural representation predicts surface normal direction, allowing us to reason about local surface reflectance. The appearance part of our neural representation is decomposed into a neural bidirectional reflectance function (BRDF), learnt as part of the fitting process, and a shadow prediction network (conditioned on light source direction) allowing us to model the apparent BRDF. This balance of learnt components with inductive biases based on physical image formation models allows us to extrapolate far from the light source and viewer directions observed during training. We demonstrate our approach on a multiview photometric stereo benchmark and show that competitive performance can be obtained with the neural density representation of a NeRF.Comment: 9 pages, 6 figures, 1 tabl

REPRESENTATION SCHEMES FOR MATHEMATICAL PROGRAMMING MODELS

Because of the difficulties often experienced in formulating and understanding large scale models, much current research is directed towards developing systems to support the construction and understanding of management science models. This paper discusses six different methods for representing mathematical programming models during the formulation phase of the modeling process. The approaches discussed in the paper include algebra, three different kinds of graphical schemes, a database-oriented approach and Structured Modeling. We emphasize representations that have graphical elements suitable for incorporation in the interface to a modeling system. The different methods are compared using a common example and conclusions are drawn as to their suitability for various modeling tasks and situations.Information Systems Working Papers Serie

Thermodynamic study of heavy metals behavior during municipal waste incineration

The incineration of municipal solid waste (MSW) contributes significantly to the presence of heavy metals in urban area aerosols. It is thus important to ascertain the quantities and chemical forms of the heavy metals (HM) that are emitted from the incineration plant stacks. The behaviour of HM, which depends strongly on the thermal and chemical environments, was investigated herein with a modelling approach, consisting of several parts. First, a refuse bed combustion model was developed for simulating on-grate MSW incineration. It describes most of the physico-chemical and thermal phenomena occurring during waste combustion. Second, results from the bed model were taken as boundary conditions to perform 3D simulations of the post-combustion zone and of the boiler. The case studied was of the Strasbourg incineration plant. Finally, the local thermal conditions and the local elementary compositions of gas and solid phases obtained from these simulations were used to carry out thermodynamic calculations of the speciation of HM at each point in the incinerator. The results for four metals (Cd, Zn, Pb, Cr) are presented, discussed and compared to available data. Predicted species are in agreement with observations for volatile metals, except lead, whose volatilization seems overestimated

Development of NiAl-Based Intermetallic Alloys: Effect of Chromium Addition

The mechanical behavior of dual-phase NiAl(Cr) microstructures, consisting of elongated primary NiAl grains aligned with an intergranular NiAl-Cr eutectic phase, produced by extrusion of a cast NiAl(Cr) alloy, has been examined. Chromium addition to create a dual phase NiAl-based aligned microstructure leads to large increases in the yield strength but no significant toughness improvement. This is achieved primarily by solid solution hardening and precipitation hardening. The constitutional hardening rate resulting from deviations from stoichiometry in the nickel-rich NiAl was estimated to be about 66 MPa per atomic per cent of nickel