841 research outputs found
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Testing geologic and geometric effects on drilling operations using torque and drag models
Intuitively, geologic and geometric effects on torque and drag should be significant. But literature suggests otherwise. Lesage et al. (1988) wrote that friction coefficients are not affected by lithology and hole angle, among other things. And if friction coefficients are similar for all of these factors, then only inclination, azimuth, and pipe specifications affect torque and drag. My thesis looks to test this statement using Johancsik’s torque and drag model and data provided by our sponsors. Johancsik’s model was chosen to test these effects because it is the most widely used torque and drag model in industry. Johancsik’s model also only relies on surface data in order to conduct an analysis. This contributes to the widespread use of Johancsik’s model and therefore increases the applicability of this paper. Once Johancsik’s model was chosen, it became natural to choose the minimum curvature method to interpolate the wellbore trajectory because Johancsik’s model was designed using the minimum-curvature method. Also, the minimum curvature method is the most widely used wellbore-interpolation method in industry. By using the minimum curvature method, this paper increases its applicability to industry. The analyses were conducted by examining the friction coefficients of each individual formation and lithology and geometric section. Friction factors encompass all factors that are not explicitly captured by the model and any factors affecting torque and drag that are not in the model will be captured by the friction factors. This study found lithology effects to affect drag consistently, though more data is needed. Drag friction factors were consistent by lithology, though they did appeared less predictable in Dataset 1 than the Datasets 2 and 3. Lithology affected torque less consistently than it did drag, though again more data is needed. Again, the results from Dataset 1 appeared to differ from Datasets 2 and 3. Further analyses are needed to conclude if this is caused by factors unrelated to lithology or individual geologies. The geometric effects of curved versus straight sections appear to not affect torque and drag. The results from the curved sections from the analyses have little relation to each other. As for more specific geometries, more analyses are needed before conclusions can be reached.Petroleum and Geosystems Engineerin
Input-output relations at dispersing and absorbing planar multilayers for the quantized electromagnetic field containing evanescent components
By using the Green-function concept of quantization of the electromagnetic
field in dispersing and absorbing media, the quantized field in the presence of
a dispersing and absorbing dielectric multilayer plate is studied.
Three-dimensional input-output relations are derived for both amplitude
operators in the -space and the field operators in the coordinate
space. The conditions are discussed, under which the input-output relations can
be expressed in terms of bosonic operators. The theory applies to both
(effectively) free fields and fields, created by active atomic sources inside
and/or outside the plate, including also evanescent-field components.Comment: 14 pages, 1 figur
An effective communication and computation model based on a hybridgraph-deeplearning approach for SIoT.
Social Edge Service (SES) is an emerging mechanism in the Social Internet of Things (SIoT) orchestration for effective user-centric reliable communication and computation. The services are affected by active and/or passive attacks such as replay attacks, message tampering because of sharing the same spectrum, as well as inadequate trust measurement methods among intelligent devices (roadside units, mobile edge devices, servers) during computing and content-sharing. These issues lead to computation and communication overhead of servers and computation nodes. To address this issue, we propose the HybridgrAph-Deep-learning (HAD) approach in two stages for secure communication and computation. First, the Adaptive Trust Weight (ATW) model with relation-based feedback fusion analysis to estimate the fitness-priority of every node based on directed graph theory to detect malicious nodes and reduce computation and communication overhead. Second, a Quotient User-centric Coeval-Learning (QUCL) mechanism to formulate secure channel selection, and Nash equilibrium method for optimizing the communication to share data over edge devices. The simulation results confirm that our proposed approach has achieved effective communication and computation performance, and enhanced Social Edge Services (SES) reliability than state-of-the-art approaches
ASXC2 approach: a service-X cost optimization strategy based on edge orchestration for IIoT.
Most computation-intensive industry applications and servers encounter service-reliability challenges due to the limited resource capability of the edge. Achieving quality data fusion and accurate service reliability with optimized service-x execution cost is challenging. While existing systems have taken into account factors such as device service execution, residual resource ratio, and channel condition; the service execution time, cost, and utility ratios of requested services from devices and servers also have a significant impact on service execution cost. To enhance service quality and reliability, we design a 2-step adaptive service-X cost consolidation (ASXC 2) approach. This approach is based on the node-centric Lyapunov method and distributed Markov mechanism, aiming to optimize the service execution error rate during offloading. The node-centric Lyapunov method incorporates cost and utility functions and node-centric features to estimate the service cost before offloading. Additionally, the Markov mechanism-inspired service latency prediction model design assists in mitigating the ratio of offload-service execution errors by establishing a mobility-correlation matrix between devices and servers. In addition, the non-linear programming multi-tenancy heuristic method design help to predict the service preferences for improving the resource utilisation ratio. The simulations show the effectiveness of our approach. The model performance is enhanced with 0.13% service offloading efficiency, 0.82% rate of service completion when transmitting data size is 400 kb, and 0.058% average service offloading efficiency with 40 CPU Megacycles when the vehicle moves 60 Km/h speed around the server communication range. Our model simulations indicate that our approach is highly effective and suitable for lightweight, complex environments
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The use of a pH-triggered polymer gelant to seal cement fractures in wells
The potential leakage of hydrocarbon fluids or CO2 out of subsurface formations through wells with fractured cement or debonded microannuli is a primary concern in oil and gas production and CO2 storage. A novel application using pH-sensitive microgel dispersion is introduced as a solution to remediation workovers using oilfield cement, which often fails to provide effective seal in smaller fractures. The application is based on the reaction of a low-pH poly(acrylic acid) polymer that can develop substantial yield stress when passing through strongly alkaline cement fractures. While the pH–trigger mechanism and rheology show promising results, an unexpected phenomenon, known as polymer syneresis, produced a byproduct that was proven to compromise the seal of the injected gel in place.
This study focuses on understanding the development of polymer viscosity and identifying the main components of syneresis. Several chemicals were studied to inhibit syneresis and tested as either polymer additives or cement pre-treatment in cement fracture corefloods. The chemical inhibitors and its applications were then selected based on not only their ability to eliminate syneresis, but also their reaction with polymer during injection and subsequent development of gel yield stress in cement fractures. Cores pre-treated with a chelating agent, known as sodium triphosphate (Na5P3O10), showed good injectivity during polymer placement and significant improved sealing performance during water breakthrough tests.
The resulting gel-in-place provided longer periods of effective seal and held pressure gradients orders of magnitude higher than just a few psi/ft from gel placed in un-treated cores. Furthermore, the comparison of holdback pressure gradients between designed corefloods indicated improvement in gel strength as fracture aperture is decreased and polymer shut-in time is increased. With proper cement pretreatment, the pH-triggered polymer-gel system has been seen to effectively plug small fractures and have valuable applications for long-term robust seal in leaky wellbores.Petroleum and Geosystems Engineerin
A quantum-inspired sensor consolidation measurement approach for cyber-physical systems.
Cyber-Physical System (CPS) devices interconnect to grab data over a common platform from industrial applications. Maintaining immense data and making instant decision analysis by selecting a feasible node to meet latency constraints is challenging. To address this issue, we design a quantum-inspired online node consolidation (QONC) algorithm based on a time-sensitive measurement reinforcement system for making decisions to evaluate the feasible node, ensuring reliable service and deploying the node at the appropriate position for accurate data computation and communication. We design the Angular-based node position analysis method to localize the node through rotation and t-gate to mitigate latency and enhance system performance. We formalize the estimation and selection of the feasible node based on quantum formalization node parameters (node contiguity, node optimal knack rate, node heterogeneity, probability of fusion variance error ratio). We design a fitness function to assess the probability of node fitness before selection. The simulation results convince us that our approach achieves an effective measurement rate of performance index by reducing the average error ratio from 0.17-0.22, increasing the average coverage ratio from 29% to 42%, and the qualitative execution frequency of services. Moreover, the proposed model achieves a 74.3% offloading reduction accuracy and a 70.2% service reliability rate compared to state-of-the-art approaches. Our system is scalable and efficient under numerous simulation frameworks
Equilibrium and stability properties of a coupled two-component Bose-Einstein condensate
The equilibrium and stability properties of a coupled two-component BEC is
studied using a variational method and the one-dimensional model of Williams
and collaborators. The variational parameters are the population fraction,
translation and scaling transformation of the condensate densities, assumed to
have a Gaussian shape. We study the equilibrium and stability properties as a
function of the strength of the laser field and the traps displacement. We find
many branches of equilibrium configurations, with a host of critical points. In
all cases, the signature of the onset of criticality is the collapse of a
normal mode which is a linear combination of the out of phase translation and
an in phase breathing oscillation of the condensate densities. Our calculations
also indicate that we have symmetry breaking effects when the traps are not
displacedComment: 13 pages,3 figure
3D harmonic loss: towards task-consistent and time-friendly 3D object detection on edge for V2X orchestration.
The use of edge computing for 3D perception has garnered interest in intelligent transportation systems (ITS) due to its potential to enhance Vehicle-to-Everything (V2X) orchestration through real-time traffic monitoring. The ability to accurately measure depth information in the environment using LiDAR has led to a growing emphasis on 3D detection based on this technology, which has significantly advanced the field of 3D perception. However, the computationally-intensive nature of these operations has made it challenging to meet the real-time deployment requirements using existing methods. The object detection task in the pointcloud domain is hindered by a substantial inconsistency problem caused by its high sparsity, which remains unaddressed. This paper conducts an in-depth analysis of the issue, which has been brought to light by recent research on detecting inconsistency problems in image specialization. To address this problem, we propose a solution in the form of a 3D harmonic loss function, which aims to alleviate the inconsistent predictions based on pointcloud data. In addition, we showcase the viability of optimizing 3D harmonic loss mathematically. Our simulations employ the KITTI dataset and DAIR-V2X-I dataset, and our proposed approach significantly surpasses the performance of benchmark models. Additionally, we validate the efficiency of our proposed model through its deployment on an edge device (Jetson Xavier TX) in a simulated environment
Decomposable representations and Lagrangian submanifolds of moduli spaces associated to surface groups
In this paper, we construct a Lagrangian submanifold of the moduli space
associated to the fundamental group of a punctured Riemann surface (the space
of representations of this fundamental group into a compact connected Lie
group). This Lagrangian submanifold is obtained as the fixed-point set of an
anti-symplectic involution defined on the moduli space. The notion of
decomposable representation provides a geometric interpretation of this
Lagrangian submanifold
Free expansion of lowest Landau level states of trapped atoms: a wavefunction microscope
We show that for any lowest-Landau-level state of a trapped, rotating,
interacting Bose gas, the particle distribution in coordinate space in a free
expansion (time of flight) experiment is related to that in the trap at the
time it is turned off by a simple rescaling and rotation. When the
lowest-Landau-level approximation is valid, interactions can be neglected
during the expansion, even when they play an essential role in the ground state
when the trap is present. The correlations in the density in a single snapshot
can be used to obtain information about the fluid, such as whether a transition
to a quantum Hall state has occurred.Comment: 5 pages, no figures. v2: discussion of neglect of interactions during
expansion improved, refs adde
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