Underreamer mechanics

In the oil and gas industry, an underreamer is a tool used to extend and enlarge the diameter of a previously-drilled bore. The problem proposed to the Study Group is to obtain appropriate mathematical models of underreamer dynamics, in forms that will lead to feasible computation. The modes of dynamics of interest are torsional, lateral and axial. This report describes some initial models, two of which are developed in more detail: one for the propagation of torsional waves along the drill string and their reflection from contact points with the well bore; and one for the dynamic coupling between the underreamer and the drill bit during drilling

A Model for the Reduction of Specific Surface Area of Powders with Age

PETN is a high explosive, sometimes stored for periods of up to many years, in powdered form. In storage, the explosive particles change size and shape owing to sublimation, condensation and surface di usion. AWE measurements are available on the changing particle size distri- bution (PSD), and the speci c surface area (SSA) of the powder, taken from experiments on accelerated ageing. But a mathematical model of the ageing process is wanted in order to interpret the processes at work. Various modelling issues and unusual features of the measure- ment data were discussed. Four models of important processes were developed, and are reported here. Model (i) addresses the fundamental physics associated with the transport of mass by sublimation, di usion and condensation. Model (ii) uses chemical kinetics to develop a system of ordinary di erential equations (ODEs) for the time-evolution of the frequencies of particle sizes. Model (iii) extends Model (ii) to a contin- uum particle size distribution. Lastly, Model (iv) considers the growth of particles as described by Cahn-Hilliard equations for the inter-particle transport of matter in Ostwald Ripening. Models (i) and (iv) include the complex geometry and thermodynamics of the problem. By con- trast, Models (ii) and (iii) focus on the time evolution of the PSD, but they are more di cult to associate with controllable variables, such as ambient temperature. Our discussions of models (ii) and (iii) suggest we can choose mass-transfer rate constants that reproduce the kind of ob- served evolution to a bimodal PSD. But more investigation is needed to determine how the rate constants may be associated with the particles' geometry and the thermodynamics of the mass transport processes

Expert recommendations on the assessment of wall shear stress in human coronary arteries : existing methodologies, technical considerations, and clinical applications

The aim of this manuscript is to provide guidelines for appropriate use of CFD to obtain reproducible and reliable wall shear stress maps in native and instrumented human coronary arteries. The outcome of CFD heavily depends on the quality of the input data, which include vessel geometrical data, proper boundary conditions, and material models. Available methodologies to reconstruct coronary artery anatomy are discussed in ‘Imaging coronary arteries: a brief review’ section. Computational procedures implemented to simulate blood flow in native coronary arteries are presented in ‘Wall shear stress in native arteries’ section. The effect of including different geometrical scales due to the presence of stent struts in instrumented arteries is highlighted in ‘Wall shear stress in stents’ section. The clinical implications are discussed in ‘Clinical applications’ section, and concluding remarks are presented in ‘Concluding remarks’ section

Argonne National Laboratory Reports

Time-dependent Ginzburg-Landau (TDGL) equations are considered for modeling a thin-film finite size superconductor placed under magnetic field. The problem then leads to the use of so-called natural boundary conditions. Computational domain is partitioned into subdomains and bond variables are used in obtaining the corresponding discrete system of equations. An efficient time-differencing method based on the Forward Euler method is developed. Finally, a variable strength magnetic field resulting in a vortex motion in Type II High-critical-temperature superconducting films is introduced. The authors tackled the problem using two different state-of-the-art parallel computing tools: BlockComm/Chameleon and PCN. They had access to two high-performance distributed memory supercomputers: the Intel iPSC/860 and IBM SP1. They also tested the codes using, as a parallel computing environment, a cluster of Sun Sparc workstations

Parallel Solution of the Time-dependent Ginzburg-Landau Equations and Other Experiences Using BlockComm-Chameleon and PCN on the IBM SP, Intel iPSC/860, and Clusters of Workstations

1 1 Introduction 1 2 Preliminaries 2 3 Test Problems 4 4 Parallel Programs with BlockComm/Chameleon 6 4.1 ProgSumBC : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 6 4.2 ProgPiBC : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 9 4.3 ProgPdeBC : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 9 4.4 ProgTdglBC : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 11 5 Clusters of Workstations as a Parallel Computing Environment 13 6 Parallel Programs with PCN 14 6.1 ProgPiPCN : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 14 6.2 ProgPdePCN : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 16 7 Conclusion 19 Acknowledgments 20 Appendix: Program Listings 21 References 37 iii Parallel Solution of the Time-dependent Ginzburg-Landau Equations and Other Experiences Using BlockComm-Chameleon and PCN on the IBM SP, Intel iPSC/860, and ..

A sensitive fluorescent chemosensor for anions based on a styryl-boradiazaindacene framework

Long wavelength emitting, extended conjugation boradiazaindacenes are novel dyes with considerable ICT character. By appending a dipicolylaminylethylamine group, the parent compound was transformed into a fluorescent dye with a strong chelating ability for Zn(II) ions. The zinc complex which has bright orange fluorescence, reversibly signals anions with very large changes in both the absorption and the emission spectra. The remarkable change in the emission intensity is explained in relation to the electron donating capacity of the substituent on the styryl functionality

An Investigation on Water Quality of Darlik Dam Drinking Water using Satellite Images

Darlik Dam supplies 15% of the water demand of Istanbul Metropolitan City of Turkey. Water quality (WQ) in the Darlik Dam was investigated from Landsat 5 TM satellite images of the years 2004, 2005, and 2006 in order to determine land use/land cover changes in the watershed of the dam that may deteriorate its WQ. The images were geometrically and atmospherically corrected for WQ analysis. Next, an investigation was made by multiple regression analysis between the unitless planetary reflectance values of the first four bands of the June 2005 Landsat TM image of the dam and WQ parameters, such as chlorophyll-a, total dissolved matter, turbidity, total phosphorous, and total nitrogen, measured at satellite image acquisition time at seven stations in the dam. Finally, WQ in the dam was studied from satellite images of the years 2004, 2005, and 2006 by pattern recognition techniques in order to determine possible water pollution in the dam. This study was compared to a previous study done by the authors in the Küçükçekmece water reservoir, also in Istanbul City

Water Quality Determination of Küçükçekmece Lake, Turkey by Using Multispectral Satellite Data

This study focuses on the analysis of the Landsat-5 TM + SPOT-Pan (1992), IRS-1C/D LISS + Pan (2000), and Landsat-5 TM (2006) satellite images that reflect the drastic land use/land cover changes in the Küçükçekmece Lake region, Istanbul. Landsat-5 TM satellite data dated 2006 was used for mapping water quality. A multiple regression analysis was carried out between the unitless planetary reflectance values derived from the satellite image and in situ water quality parameters chlorophyll a, total phosphorus, total nitrogen, turbidity, and biological and chemical oxygen demand measured at a number of stations homogenously distributed over the lake surface. The results of this study provided valuable information to local administrators on the water quality of Küçükçekmece Lake, which is a large water resource of the Istanbul Metropolitan Area. Results also show that such a methodology structured by use of reflectance values provided from satellite imagery, in situ water quality measurements, and basin land use/land cover characteristics obtained from images can serve as a powerful and rapid monitoring tool for the drinking water basins that suffer from rapid urbanization and pollution, all around the world

Evaluation of some biochemical parameters of pediatric patients hospitalized for rotavirus in Şırnak Province: A retrospective review

Rotavirus gastroenteritis is an important cause of worldwide morbidity and mortality in infants and children. The main cause of mortality is dehydration due to fluid loss and malnutrition. This study aims to examine the guiding parameters of uric acid and creatinine levels in the detection of dehydration and fluid deficit and inpatient management in cases of rotavirus gastroenteritis. Children who applied to Şırnak State Hospital, Pediatrics Polyclinics, children (6 months-18 years old) whose faecal samples were sent to the laboratory by the research pediatrician considering the diagnosis of rotavirus and whose microbiological examinations were confirmed by immunochromatographic methods (6 months-18 years old), were included in the study by scanning the system. When positive patients were evaluated, the mean age for serum uric acid was 1.06±1.53 and the mean age for serum creatinine was 1.10±1.37. The median value was 3.75 mg/dL in negative patients with serum uric acid levels, and 5.25 mg/dL in positive patients, which was statistically significant (p [Med-Science 2023; 12(3.000): 823-6

Long-term effects of a rehabilitation program on the clinical outcomes, social functionality, and life quality of schizophrenic patients-a follow-up study

Objective: Schizophrenia is a severe brain disease which leads to progressive clinical, cognitive, social, and vocational deterioration. The results of a meta-analysis of studies from more than 100 years showed that the progress and outcomes of schizophrenia remain poor. However, evidence-based strategies combining pharmacological and psychosocial treatments have obtained promising results and increased expectations regarding the outcome of schizophrenia. This study examined the effects of a multimodal, psychosocial intervention program for schizophrenic patients at the end of the program and three years later. Methods: The study involved 60 patients between 18 and 65 years old who had been diagnosed with schizophrenia but had not participated in a multimodal, psychosocial intervention program. At the beginning of, end of, and three years after the six-month program, all patients were assessed with the Bakirkoy Rehabilitation Form for Patient with Chronic Mental Illness, Positive and Negative Syndrome Scale, Morisky's Questions--Self-Report Measure of Adherence, Quality of Life Scale, Insight into the Three Components of the Evaluation Scale, Social Functioning Scale, and Disability Assessment Schedule. The three sets of measurements were compared to each other. Findings: In the end-of-program and third-year measurements, the severity of the symptoms had statistically and significantly decreased compared to measurements made before the program. As well, the frequency of hospitalizations decreased, while adherence to treatment, insight level, social functionality, and quality of life increased. Discussion: The structured psychosocial interventions used throughout the program were found to increase patients' insight level and adherence to treatment, which resulted in decreased severity of symptoms and frequency of hospitalizations. Recovery from negative symptoms, which the literature shows to be the most important causes of decreased social and professional functionality, could explain the increase in the scale scores measuring social functionality and quality of life. Likely also contributing to this result was the intense use of techniques in such areas as independent living skills, interpersonal relations, daily life activities, and social affairs and behaviors. Results: The results of this study are important. They show that the applied program is effective and that its positive effects lasted three years after it ended. This program can serve as a model for the community mental health centers opening during the transition to and establishment of a community-based psychiatric system in Turkey