An adaptive finite element method for laser surface hardening of steel problem

ACMAC’s PrePrint Repository aim is to enable open access to the scholarly output of ACMAC

A priori error estimates for the optimal control of laser surface hardening of steel

A priori error estimates for the optimal control of laser surface hardening of stee

Multimapper: Data Density Sensitive Topological Visualization

Mapper is an algorithm that summarizes the topological information contained in a dataset and provides an insightful visualization. It takes as input a point cloud which is possibly high-dimensional, a filter function on it and an open cover on the range of the function. It returns the nerve simplicial complex of the pullback of the cover. Mapper can be considered a discrete approximation of the topological construct called Reeb space, as analysed in the $1$-dimensional case by [Carriere et al.,2018]. Despite its success in obtaining insights in various fields such as in [Kamruzzaman et al., 2016], Mapper is an ad hoc technique requiring lots of parameter tuning. There is also no measure to quantify goodness of the resulting visualization, which often deviates from the Reeb space in practice. In this paper, we introduce a new cover selection scheme for data that reduces the obscuration of topological information at both the computation and visualisation steps. To achieve this, we replace global scale selection of cover with a scale selection scheme sensitive to local density of data points. We also propose a method to detect some deviations in Mapper from Reeb space via computation of persistence features on the Mapper graph.Comment: Accepted at ICDM

Dual weighted residual method for laser surface hardening of steel problem

Abstract. The main focus of this article is on the development of Adaptive Finite Element Method (AFEM) for the optimal control problem of laser surface hardening of steel governed by a dynamical system consisting of a semi-linear parabolic equation and an ordinary differential equation using Dual Weighted Residual Method (DWR). A posteriori error estimators using DWR method have been developed when a continuous piecewise linear discretization has been used for the finite element approximation of space variables and a discontinuous Galerkin method has been used for time and control discretizations. Further numerical results obtained are presented are compared with residual method numerical results. Key Words. Laser surface of steel problem, Adaptive finite element methods, Dual weighted residual methods, a posteriori error estimates. 1

Effect of Nano-Pore Wall Confinements on Non-Ideal Gas Dynamics in Organic Rich Shale Reservoirs

The advancements in horizontal well drilling and multistage hydraulic fracturing technology enabled us to unfold major sources of hydrocarbon trapped in ultra-tight formations such as tight sands and organic rich shales. Tremendous gas production from these reservoirs has transformed today\u27s energy landscape. To effectively optimize the hydrocarbon production from these ultra-tight formations, it is essential to study and model the fluid transport and storage sealed in multiscale pore structure of these formations, i.e. micro-, meso- and macro-pores. In shale gas reservoirs, Kerogen, the finely dispersed organic nano-porous material with an average pore size of less than 10 nm holds bulk of the total gas in place (GIP) in an adsorbed state. The molecular level interactions between fluid-fluid and fluid-solid organic pore walls govern the transport and storage in these organic nano-pores. Among different methods used to model gas dynamics in organic nano-pores such as the multi-continuum, molecular dynamics and Monte Carlo, the lattice Boltzmann method (LBM) is a more effective method with much less computational cost relative to other techniques. This is due to the applicability of this technique in wide range of flow regimes and ease of handling complex boundary conditions such as incorporation of the molecular interactions in porous media.;The objective of this research is to develop a two-dimensional LBM of organic rich shales that can be used to quantify the effect of organic pore wall confinement on non-ideal gas flow and storage in organic nano-pores of the shale reservoirs. This method incorporates the involvement of molecular forces between fluid particles such as, adsorptive and cohesive forces. Using the Langmuir-slip boundary condition at capillary walls, slippage of free gas molecules and surface transport of adsorbed molecules are studied. This effect is investigated in a large range of Knudsen numbers from continuum flow to transition flow regime with varying capillary width sizes from 100 nm to 5 nm.;Simulation results concentrates on the molecular phenomena like- adsorptive/cohesive forces, and the kinetic energy of the fluid molecules at different pressures, and reservoir temperatures. The LBM model results displays a clear indication that the gas transport in the capillary tube is depends on the pore width size. A critical Knudsen number exists with changing reservoir conditions, where the anticipated fluid velocity profile in organic nano-pores alters showing higher flow rate as capillary widths reduces due to the underlying effect of molecular phenomena of double slippage and wall confinement, introduced earlier by Fathi et al. These results are compared with traditional continuum Hagen-Poiseuille law, Klinkenberg slip theory, and recent modified version of Klinkenberg slip flow equation. This work is not only important for the advancement of shale gas flow simulator, but also for organic rich shale characterization

Changing trends in incidence, type, indication and maternal outcome of peripartum hysterectomy over 10 years at a tertiary care centre

Background: Peripartum hysterectomy is the most dramatic operation in modern obstetrics and is generally performed when all conservative measures fail to achieve haemostasis in the setting of life threatening haemorrhage. The objective was to review all peripartum hysterectomies performed at a tertiary care centre over a ten-year period from 2007 to 2016 to determine the incidence, types, indications and maternal outcome and also to study the changing trendsMethods: This was a retrospective, observational, analytical study of parturient women requiring peripartum hysterectomy (PH). We looked at data over a ten-year period, from January 2007 to December 2016. Case records were reviewed for socio-demographic characteristics of the patients, type and indications for the hysterectomy performed, booking status of patients, mode of delivery, gestational age at delivery and maternal outcome. Change in trends of the rate and indications of peripartum hysterectomy at the centre was also reviewed.Results: The overall rate of peripartum hysterectomy was 1/876 deliveries. The rate of peripartum hysterectomy had a 4-fold rise from 2007 to 2016.The primary indication was abnormal placentation which included morbidly adherent placentation 22/59 (37.2%) and placentapraevia 5/59 (8.4%), followed by intractable atonic haemorrhage in 35.6% of cases. Abnormal placentation as an indication for PH increased significantly form 34.6% (2007-2011) to 54.54% (2012-2016). After hysterectomy, 56% cases were admitted to ICU. All patients needed blood transfusion. Maternal mortality was 10.1%.Conclusions: Peripartum hysterectomy is a most demanding obstetric surgery performed in very trying circumstances of life threatening hemorrhage. The indication for emergency peripartum hysterectomy in recent years has changed from traditional uterine atony to abnormal placentation.

Fine needle cytology-diagnostic tool for palpable orbital and eyelid lesions

Background: Fine needle aspiration cytology in orbital lesions gained importance in the last 3 decades. FNAC can be used for aiding the clinician to plan treatment of orbital and eyelid tumors study was undertaken to evaluate the role of FNAC as a diagnostic tool for diagnosis and management of various orbital and eyelid lesions, as it is of great value in the diagnosis of new primary, recurrent and metastatic orbital tumors.Methods: Patients of different age groups presenting with orbital and eyelid lesions were studied over a period of 4 years from March 2013 to Feb 2017. The 75 patients selected for this study were clinically evaluated and then investigated with computed tomograpghy (CT) scanning. Each patient was subjected to FNAC under direct vision/ultrasongraphy guidance with sterile 22 guage needle without anaesthesia. Biopsy was done to confirm the cytological diagnosis.Results: The age of patients varied from 3 years to 70 years. On cytology 61 cases were benign and 14 malignant. Histopathological examination of 53 cases was done which confirmed the cytological diagnosis.Conclusions: FNAC is a useful, rapid, safe and cost effective method for diagnosing orbital and eyelid pathology

A study of Black Box Testing to generate the test cases and Statement coverage criteria to reduce the test cases

No Abstrac

Feto-maternal outcome in second versus first stage caesarean delivery in a tertiary medical care centre

 Background: The aim is to study neonatal and maternal outcomes of the caesarean sections performed in first stage versus second stage of labour. Methods: The retrospective analysis of data were done of caesarean section done at Department of Obstetrics and Gynaecology at ESI PGIMSR Basaidarapur New Delhi between January 2016 to December 2016. 45 women, who underwent second stage caesarean section were studied. For each case, two consecutive cases, who underwent caesarean delivery during the first stage of labour were taken as control for the study. Primary maternal outcomes of interest were uterine atonia, transfusion requirement, urinary system injury and postoperative complications. Results: Out of 4477 deliveries, 1466 had caesarean section with a rate of 32%. The rate of second stage caesarean section was 3% of total caesarean section and 1% of total deliveries. Second stage caesarean section had higher maternal and perinatal morbidity like atonic PPH (33.3%), lower uterine segment extension (7%), febrile morbidity (10%), and need for blood transfusion (15%). There were 15.5% NICU admission in second stage caesarean group while none in first stage group. Conclusions: Caesarean section in the second stage of the labour is associated with increased maternal and neonatal morbidities. Special attention is required to the patients undergoing caesarean section in the second stage of the labour. They should be handled by senior and experienced obstetrician. Neonatologist should be present for every second stage caesarean section