Fast One-dimensional Finite Element Approximation of Geophysical Measurements

There exist a wide variety of geophysical prospection methods. In this work, we focus on resistivity methods. We categorize these resistivity prospection methods according to their acquisition location as (a) on the surface, such as the ones obtained using Controlled Source Electromagnetics (CSEM) and magnetotelluric, and (b) in the borehole, such as the ones obtained using Logging-While-Drilling (LWD) devices. LWD devices are useful both for reservoir characterization and geosteering purposes, which is the act of adjusting the tool direction to travel within a specific zone. When inverting LWD resistivity measurements, it is a common practice to consider a one-dimensional (1D) layered media to reduce the problem dimensionality using a Hankel transform. Using orthogonality of Bessel functions, we arrive at a system of Ordinary Differential Equations (ODEs); one system of ODEs per Hankel mode. The dimensionality of the resulting problem is referred to as 1.5D since the computational cost to resolve it is in between that needed to solve a 1D problem and a 2D problem. When material properties (namely, resistivity, permittivity, and magnetic permeability) are piecewise-constant, we can solve the resulting ODEs either (a) analytically, which leads to a so-called semi-analytic method after performing a numerical inverse Hankel transform or (b) numerically. Semi-analytic methods are faster, but they also have important limitations, for example, (a) the analytical solution can only account for piecewise constant material properties, and other resistivity distributions cannot be solved analytically, which prevents to accurately model, for example, an Oil-Water Transition (OWT) zone when fluids are considered to be immiscible; (b) a specific set of cumbersome formulas has to be derived for each physical process (e.g., electromagnetism, elasticity, etc.), anisotropy type, etc.; (c) analytical derivatives of specific models (e.g., cross-bedded formations, or derivatives with respect to the bed boundary positions) are often difficult to obtain and have not been published to the best of our knowledge. In view of the above limitations, we propose to solve our forward problems using a numerical solver. A traditional Finite Element Method (FEM) is slow, which makes it unfeasible for our application. To achieve high performance, we developed a multiscale FEM that pre-computes a set of optimal local basis functions that are used at all logging positions. The resulting method is slow when compared to a semi-analytic approach for a single logging position, but it becomes highly competitive for a large number of logging positions, as needed for LWD geosteering applications. Moreover, we can compute the derivatives using an adjoint state method at almost zero additional cost in time. We describe an adjoint-based formulation for computing the derivatives of the electromagnetic fields with respect to the bed boundary positions. The key idea to obtain this adjoint-based formulation is to separate the tangential and normal components of the field, and treat them differently. We then apply this method to a 1.5D borehole resistivity problem. Moreover, we compute the adjoint-state formulation to compute the derivative of the magnetic field with respect to the resistivity value of each layer. We verify the accuracy of our formulations via synthetic examples. When simulating borehole resistivity measurements in a reservoir, it is common to consider an Oil-Water Contact (OWC) planar interface. However, this consideration can lead to an unrealistic model since, in the presence of capillary pressure, the mix of two immiscible fluids (oil and water) often appears as an OWT zone. These transition zones may be large in the vertical direction (20 meters or above), and in context of geosteering, an efficient method to simulate an OWT zone can maximize the production of an oil reservoir. In this work, we prove that by using our proposed 1.5D numerical method, we can easily consider arbitrary resistivity distributions in the vertical direction, as it occurs in an OWT zone. Numerical results on synthetic examples demonstrate significant differences between the results recorded by a geosteering device when considering a realistic OWT zone vs. an OWC sharp interface. As an additional piece of work of this Ph.D. Dissertation, we explore the possibility of using a Deep Neural Network (DNN) to perform a rapid inversion of borehole resistivity measurements. Herein, we build a DNN that approximates the following inverse problem: given a set of borehole resistivity measurements, the DNN is designed to deliver a physically meaningful and data-consistent piecewise one-dimensional layered model of the surrounding subsurface. Once the DNN is built, the actual inversion of the field measurements is efficiently performed in real time. We illustrate the performance of a DNN designed to invert LWD measurements acquired on high-angle wells via synthetic examples

Borehole Resistivity Simulations of Oil-Water Transition Zones with a 1.5D Numerical Solver

When simulating borehole resistivity measurements in a reservoir, it is common to consider an oilwater contact (OWC) planar interface. However, this consideration can lead to an unrealistic model since in the presence of capillary actions, the mix of two immiscible fluids (oil and water) often appears as an oil-water transition (OWT) zone. These transition zones may be signi cant in the vertical direction (20 meters or above), and in context of geosteering, an e cient method to simulate the OWT zone can maximize the production of an oil reservoir. Herein, we propose an e cient one and a half dimensional (1.5D) numerical solver to accurately simulate the OWT zone in an oil reservoir. Using this method, we can easily consider arbitrary resistivity distributions in the vertical direction, as it occurs in an OWT zone. Numerical results on synthetic examples demonstrate signi cant di erences between the results recorded by a geosteering device when considering a realistic OWT zone vs an OWC sharp interface

Measurement and Correlation of Phase Diagram Data of Hydrophilic Alcohols (1-Propanol/2-Propanol) + Salts (Na2SO4/(NH4)2SO4/NH4NO3) + Water Systems

Binodal data and the ternary liquid–liquid equilibria (LLE) was experimentally determined at 298.15 K for hydrophilic alcohols (1-propanol or 2-propanol) + salts (Na2SO4, (NH4)2SO4 or NH4NO3) + water systems. The salting-out and the phase-forming abilities of the salts and alcohols for the investigated ATPSs were discussed. The salting-out abilities of the investigated salts follow the order Na2SO4 > (NH4)2SO4 > NH4NO3, which can be indicated by the location of the binodal curves plotted in mass fraction, the effective excluded volume (EEV), the salting-out coefficient (Ks), the size of the ions, and the Gibbs free energy of hydration of the ions. The phase-separation ability of the studied hydrophilic alcohols was discussed on the basis of the dielectric constant and boiling point of the alcohols. The results show that the phase-separation capability of the system consists of different hydrophilic alcohols in the order: 1-propanol>2-propanol. Furthermore, the binodal curves of the studied systems were satisfactorily correlated by a nonlinear equation with four parameters. The reliability of the calculation method and the corresponding LLE data was successfully proved by the Othmer-Tobias equation and the Bancroft equation

Development of a curriculum for endoscopy nurse education in Iran

Abstract Introduction: Nursing as a discipline and a profession is following to meet the needs of clients in clinical settings. The nurse participation and cooperation in the programs of diagnostic and therapeutic endoscopy has not been recorded in Iran. On the other hand, health care system needs to provide specialized care for patients under endoscopy. The aim of this study was to develop a professional curriculum for endoscopy nurse education in Iran. Method: This was a study to approve the content and curriculum for endoscopy nurse education in Iran using the Delphi method. This study carried out in three phases; a review of the literature on endoscopy nursing courses and training program in the world; assessment of expert groups and individuals associated with gastrointestinal endoscopy; and finally, a consensus on the curriculum of nursing endoscopy and its implementation. Results: Based on the endoscopy nurse training needs, eight priorities for education endoscopy nurse including theory, practical, and clinical professional was determined. Total hours of training were 210 hours, including 140 hours for theoretical and practical courses and 70 hours of clinical training. Different strategies were used to teach the theoretical and practical subjects. For theoretical teaching, lectures, group work, and self-learning were applied. Role Playing and simulation were used for practical training; and for clinical training, endoscopy clinical practice settings were determined. Conclusion: This training program was based on a participant survey on the digestive endoscopy and educational needs. This educational curriculum involved learning different areas of knowledge, attitudes, and skills for nurses to train caring of patients undergoing gastrointestinal endoscopy through an inter-professional education program. These special nursing educational programs can be contributed to the professional development of Iranian nurses

Comparative Study of Job Burnout Among Critical Care Nurses With Fixed and Rotating Shift Schedules

Background: Nurses, as health care providers, are insurmountably obliged to the practice of shift work. Literature has reported shift working as one of the inducing factors of burnout. Despite numerous studies in this area, there are inconsistencies on the relationship between shift working and burnout among nurses, especially in those who work in critical care settings. Objectives: The aim of this study was to compare the occupational burnout in critical care nurses with and without fixed shift schedules. Patients and Methods: In this comparative study, 130 nurses with rotating shift schedule and 130 nurses with fixed shift schedule from six university hospitals were selected using stratified random sampling. Maslach burnout inventory was used for data collection. Independent samples t-test, chi-square and one-way ANOVA tests were used to analyze the data. Results: Most of the participants were females (62.7%), aged between 22 - 29 years (38.5%), married (59.2%), and had a bachelor degree (86.9%). The mean score of emotional exhaustion was significantly higher in nurses with fixed shift schedules (P 0.05). Moreover, no significant difference was found in burnout mean scores between nurses with fixed morning and fixed night shifts (P > 0.05). The means of the emotional exhaustion subscale were significantly different in nurses with different characteristics (P < 0.05) except the gender and working unit. Conclusions: As a result of this study, it was found that critical care nurses with fixed shift schedules display more burnout in emotional exhaustion dimension, compared to those working with rotating shift schedules

A Deep Neural Network as Surrogate Model for Forward Simulation of Borehole Resistivity Measurements

Inverse problems appear in multiple industrial applications. Solving such inverse problems require the repeated solution of the forward problem. This is the most time-consuming stage when employing inversion techniques, and it constitutes a severe limitation when the inversion needs to be performed in real-time. In here, we focus on the real-time inversion of resistivity measurements for geosteering. We investigate the use of a deep neural network (DNN) to approximate the forward function arising from Maxwell's equations, which govern the electromagnetic wave propagation through a media. By doing so, the evaluation of the forward problems is performed offline, allowing for the online real-time evaluation (inversion) of the DNN

Adjoint-based formulation for computing derivatives with respect to bed boundary positions in resistivity geophysics

In inverse geophysical resistivity problems, it is common to optimize for specific resistivity values and bed boundary positions, as needed, for example, in geosteering applications. When using gradient-based inversion methods such as Gauss-Newton, we need to estimate the derivatives of the recorded measurements with respect to the inversion parameters. In this article, we describe an adjoint-based formulation for computing the derivatives of the electromagnetic fields withrespect to the bed boundary positions. The key idea to obtain this adjoint-based formulation is to separate the tangential and normal components of the field, and treat them differently. We then apply this method to a 1.5D borehole resistivity problem. We illustrate its accuracy and some of its convergence properties via numerical experimentation by comparing the results obtained with our proposed adjoint-based method vs. both the analytical results when available and a finite differences approximation of the derivative

Caregiver burden among Iranian heart failure family caregivers: A descriptive, exploratory, qualitative study

Background: Living with patients of chronic diseases such as heart failure (HF) is a diffi cult situation for the caregivers. This study explored the Iranian family caregivers’ burden of caregiving for patients with HF. Materials and Methods: Eighteen family caregivers of the HF patients from two governmental medical training centers in Isfahan, Iran were recruited using purposive sampling. Data were collected through face-to-face semi-structured interviews. Each interview was transcribed verbatim and was thematically analyzed concurrently. Results: Four major themes emerged from the analysis of the transcripts: Lack of care-related knowledge, physical exhaustion, psychosocial exhaustion, and lack of support. Family caregivers believed that they have little knowledge about the patients’ disease, drugs, and how to perform caregiving roles. They experienced negative physical and psychosocial consequences of full-time and highly extended caregiving roles, such as musculoskeletal disorder, fatigue, and sleep disturbance, and a high level of anxiety, stress, and social isolation. Caregivers believed that they receive little familial and organizational support on the emotional and fi nancial dimensions of caregiving. Conclusions: The fi ndings of this study can be used by healthcare providers, especially nurses, to provide more effective social, informational, and professional support for family caregivers

The effectiveness of a supportive educative group intervention on family caregiver burden of patients with heart failure.

BACKGROUND Living with heart failure patients is a complex situation for family caregivers. Few studies have been conducted to examine the effects of interventional programs to ease this condition. The purpose of this study was to determine the effectiveness of a supportive educative group intervention in reducing family caregivers' burden of caregiving. MATERIALS AND METHODS This randomized clinical trail was conducted at a selective teaching hospital in Isfahan, Iran in 2012. The intervention consisted of four weekly multimedia training sessions of 2 h that included education and family support for 50 family caregivers. Caregiver burden was measured using the Zarit Burden Interview (ZBI). Paired t-test, Student's t-tests, and repeated measures analysis of variance (ANOVA) were used to test for significant differences of the mean scores of burden between the intervention and control groups over a 3-month period. RESULTS The intervention was successful in reducing caregiver burden over time both at the end of the intervention period (P = 0.000) and 3 months after the intervention (P = 0.000). CONCLUSIONS Nurses and other healthcare providers can use the findings of this study in order to implement effective programs to reduce family caregivers' challenges and to provide them more support