Conventional Expansion Research Articles

Study on Thermal Chamber Expansion of VH-SAGD Process Using CO2-Inducing Effect for Heavy Oil Reservoirs

In heavy oil thermal recovery processes, higher pressure usually leads to low dryness and expansion difficulty for the injected steam in thermal recovery processes, which will result in lower oil recovery and more carbon emissions. This paper proposed a new CO2-inducing method to accelerate the steam chamber expansion, based on a core flooding experiment and numerical simulation. First, the CO2 showed significant viscosity reduction at high pressure in the PVT test. In the core flooding experiment, the CO2 provided strong flow conductivity in porous media for the thermal flooding, as the CO2 pre-injection restrained the steam condensation. Using the CO2-inducing method, CO2 pre-injection before steam built a fast flow channel in a relatively higher permeability layer and reduced the thermal injection pressure by about 1.0~2.4 MPa. As a result, the steam overlap around the injection wells became slower and the gravity drainage process was able to heat and displace the heavy oil above the channel. Furthermore, the CO2 gas trapped at the top reduced heat loss by about 12.4%. The field numerical simulation showed that this new method improved thermal recovery by 7.5% and reduced CO2 emissions by about 18 million kg/unit for the whole process. This method changes the conventional thermal expansion direction by CO2 inducing effect and fundamentally reduces heat loss, which provides significant advantages in low-carbon EOR.

Investigation on directional rock fracture mechanism under instantaneous expansion from the perspective of damage mechanics: A 3-D simulation

With developments in geotechnical engineering, directional rock-breaking technology has been applied in large quantities. As a novel non-explosive rock-breaking technology, Instantaneous Expansion with a Single Crack (IESC) has been studied and applied to some extent in the past few years. IESC uses expansion gas to fracture rock mass in the predetermined direction by a special energy-gathering tube, which has the advantages of high safety, strong directional ability, and easy to operate. At present, there is a lack of in-depth investigation on the directional fracture mechanism of rock under the action of IESC. According to damage mechanics, the fundamental reason for rock fracture is due to the initiation, expansion, and penetration of internal cracks. In this study, a 3-D numerical model based on the theory of progressive failure is established to study the directional rock fracture mechanism of IESC, while a Conventional Expansion (CE) model without energy-gathering tube is established for comparative research. The maximum tensile stress criterion and unified strength criterion are used to identify damage failure of the element. The evolution processes of four key parameters are simulated, the types and degrees of tensile/compressive damage of the unit are analyzed, which aims to decipher the model's directional fracture mechanism under IESC loading. The established 3-D numerical models are validated by comparing with experimental results. The research results can contribute to further understanding the directional rock fracture mechanism of IESC and provide a theoretical basis for the application of IESC in the field.

Experimental performance comparison of various expansion devices for small-capacity subcritical R744 vapour-compression refrigeration units

The target of this study is to experimentally compare the performance of three different expansion devices for small-capacity subcritical R744 vapour-compression refrigeration units. The first considered expansion device was the conventional high-pressure expansion valve, which was selected as the baseline. The second assessed expansion device was a two-phase ejector for expansion work recovery whose refrigerant flow was modulated via the pulse-width modulation (PWM) strategy. Finally, the PWM approach was employed for controlling the refrigerant flow of the ejector motive nozzle while the refrigerant was not permitted to be drawn by the ejector suction nozzle. The results showed that the motive nozzle controlled via PWM effect offers similar effectiveness to a conventional high-pressure expansion valve in the subcritical regime. Furthermore, it was observed that the PWM ejector is able to control the high pressure effectively while increasing the coefficient of performance (COP) by up to 5.3 % without and by up to 7.9 % with overfed evaporator compared to the baseline in the transition regime. The results also showed that the installation of the conventional high-pressure expansion valve is not necessary. Finally, the yearly performance of the aforementioned expansion devices was assessed in five different locations, i.e., Athens (Greece), Phoenix (USA), New Delhi (India), Riyadh (Saudi Arabia) and Bangkok (Thailand). The outcomes revealed that the PWM ejector allows for a higher in yearly average COP (COPyearly avg) from 4.9 % (in Athens) to 11.8 % (in Bangkok) over the baseline.

Expansion planning of hybrid electrical and thermal systems using reconfiguration and adaptive bat algorithm

_ This study introduces a comprehensive model for the concurrent expansion planning of various energy systems and their associated equipment. The need to reduce network costs, emissions, losses, and feeder loading, as well as to enhance network reliability and voltage profile, mandates the utilization of proper multi-objective planning models that respect all network constraints. The introduced framework includes units for generating both electrical and thermal energies. The model leverages conventional expansion alternatives such as the installation of new lines, network reconfiguration, rewiring, and the addition of new thermal and electrical generating units to the network. Expansion planning involves determining the optimal time, location, and type of new installations to meet future energy demands while minimizing costs and emissions. Reconfiguration refers to altering the network topology to improve reliability and reduce losses. The proposed expansion planning is formulated as a discrete, nonlinear, and non-convex optimization problem, which is solved using the Self Adaptive Learning Bat Algorithm (SALBA). This algorithm improves convergence speed and increases the diversity of the search population, enhancing the likelihood of finding the global optimum. Numerical simulations of the proposed methodology on two modified standard IEEE test systems corroborate the efficacy and feasibility of the suggested approach. Key innovations include the comprehensive modeling for concurrent expansion planning, the use of an advanced optimization algorithm, and a focus on reducing costs, emissions, losses, and feeder loading while enhancing network reliability and voltage profile.

On the role of longitudinal currents in radiating systems of charges

The time derivative of a charge density is linked to a current density by the continuity equation. However, it features only the longitudinal part of a current density, which is known to produce no radiation. This fact usually remains unnoticed and may appear puzzling at first, suggesting that the temporal variation of a charge density should be also irrelevant to radiation. We alleviate the apparent contradiction by showing that the effective longitudinal currents are not spatially confined, even when the time-dependent radiating charge density that generates them is. This enforces the co-existence of the complementary, i.e. transverse, part of the current, which, in turn, gives rise to radiation. We illustrate the necessarily delocalized nature and relevance of longitudinal currents to the emission of electromagnetic waves by a dynamic electric dipole, discussing the practical implications of that for radation in partially conducting condensed matter. More generally, we show how the connection between the longitudinal and transverse currents shapes the structure of the conventional multipole expansion and fuels the ongoing confusion surrounding the charge and toroidal multipoles.

Comparison of the Outcomes of the Conventional Blunt Uterine Expansion Technique to Cephalad-caudad Expansion in Cesarean Section: A Randomized Controlled Trial

Comparison of the Outcomes of the Conventional Blunt Uterine Expansion Technique to Cephalad-caudad Expansion in Cesarean Section: A Randomized Controlled Trial

Hydraulic Expansion Techniques for Fracture-Cavity Carbonate Rock with Field Applications

Fracture-cavity carbonate reservoirs provide a large area, fracture development, high productivity, long stable production time, and other characteristics. However, after long-term exploitation, the lack of energy in the formation leads to a rapid decrease in production, and the water content in crude oil steadily increases, thereby disrupting normal production. To recover normal production, it is necessary to connect the cracks and pores that have not been affected during the original production, so as to allow the crude oil inside to enter the production cracks and replenish energy through methods such as hydraulic expansion of fracture-cavity carbonate rock. Accordingly, we propose hydraulic expansion techniques based on the following four processes for implementation: (1) applying high pressure to prevent a nearby fracture network from opening the seam, (2) connecting a distant fracture-cavity body, (3) breaking through the clay filling section of a natural fracture network, and (4) constructing an injection production well pattern for accelerating injection and producing diversion. Hydraulic fracturing involves closing or partially closing the original high-permeability channels, which usually produce a large amount of water, while opening previously unaffected areas through high pressure to increase crude oil production. We also introduce two composite techniques: (1) temporary plugging of the main deep fractures, followed by hydraulic expansion; and (2) capacity expansion and acidification/pressure processes. Hydraulic expansion allowed us to recover and supplement the formation energy and efficiently increase production. We tested various wells, achieving an effective hydraulic expansion rate of up to 85%. In addition, the productivity of conventional water injection and hydraulic expansion after on-site construction was compared for one well, clearly indicating the effectiveness of water injection and the remarkable crude oil increase after hydraulic expansion.

Structurally and mechanically tuned macroporous hydrogels for scalable mesenchymal stem cell–extracellular matrix spheroid production

Mesenchymal stem cells (MSCs) are essential in regenerative medicine. However, conventional expansion and harvesting methods often fail to maintain the essential extracellular matrix (ECM) components, which are crucial for their functionality and efficacy in therapeutic applications. Here, we introduce a bone marrow-inspired macroporous hydrogel designed for the large-scale production of MSC-ECM spheroids. Through a soft-templating approach leveraging liquid-liquid phase separation, we engineer macroporous hydrogels with customizable features, including pore size, stiffness, bioactive ligand distribution, and enzyme-responsive degradability. These tailored environments are conducive to optimal MSC proliferation and ease of harvesting. We find that soft hydrogels enhance mechanotransduction in MSCs, establishing a standard for hydrogel-based 3D cell culture. Within these hydrogels, MSCs exist as both cohesive spheroids, preserving their innate vitality, and as migrating entities that actively secrete functional ECM proteins. Additionally, we also introduce a gentle, enzymatic harvesting method that breaks down the hydrogels, allowing MSCs and secreted ECM to naturally form MSC-ECM spheroids. These spheroids display heightened stemness and differentiation capacity, mirroring the benefits of a native ECM milieu. Our research underscores the significance of sophisticated materials design in nurturing distinct MSC subpopulations, facilitating the generation of MSC-ECM spheroids with enhanced therapeutic potential.

Short- and long-term effects of conventional and miniscrew-assisted rapid palatal expansion on hard tissues using voxel-based superimposition of serial cone-beam computed tomography scans

The objective of this study was to evaluate the short-term and long-term hard-tissue changes with miniscrew-assisted rapid palatal expansion (MARPE) and rapid palatal expansion (RPE) compared with a matched control group with voxel-based superimposition using 3-dimensional cone-beam computed tomography (CBCT) scans. A total of 180 CBCT scans were analyzed for 60 patients with a mean age of 13.9 years at 3 time points: pretreatment (T1), postexpansion (T2), and posttreatment (T3). Patients were divided into 3 groups: MARPE, RPE, and controls. Voxel-based superimposition was performed for CBCTs from T1 to T2 and T1 to T3 using the anterior cranial base as a reference. The hard-tissue surfaces were extracted after the superimposition procedure. Nine landmarks were analyzed: nasion, A-point, pogonion, left and right alar bases, zygoma, and gonion. Within-group changes were analyzed using linear mixed-effects models, including a random intercept per subject and the mixed effect of time (T1, T2, or T3) with test P values adjusted for multiple testing using Tukey's method. Between-group changes were analyzed using linear mixed-effects models, including a random intercept per subject and the mixed effects of time, group, and group × time interaction with P values adjusted for multiple testing using the Benjamin-Hochberg false discovery rate method. In the short term, both MARPE and RPE led to a significant downward movement of the right gonion and lateral movement of the right alar base compared with controls at T2 (P<0.05). In addition, MARPE led to a significant downward movement of pogonion and left gonion. RPE led to a significant downward movement of the A-point and lateral movement of the left alar base compared with controls at T2 (P<0.05). However, in the long-term, no changes were observed between the groups at T3. There were significant differences in pogonion, alar base, and gonion between MARPE, RPE, and control groups in the short term. However, all the hard-tissue changes were transient, as there were no differences between the 3 groups in the long term.

Effects of prepulse on hot electron emission from mesoscopic particles

In this paper we make an attempt to study the effect of a nanosecond prepulse on electron acceleration from microscopic solid particles. While standard scaling laws predict temperatures of ∼50 keV, our investigations showed an anomalous enhancement ( ∼200 keV) in electron temperatures from microscopic solids subjected to intense laser fields. Conventional isotropic expansion of the plasma target as a result of pre-pulse interaction is unable to explain the enhancement, prompting an experimental inquiry into the expansion form. Tentacle-like structures emerging from the spherical plasma are detected as an outcome of the pre-pulse interaction, with the region between the tentacles being targeted by the main laser pulse. We resort to PIC simulations to understand and predict the exact plasma condition that exists in this region. In this paper, we study a series of approximate pre-plasma conditions, particle shapes, and electron densities, examining them for their role in electron acceleration from this extended over-critical plasma target.

Microstructure and mechanical performance of polyurethane-fly ash composites (PU-FAC) under different effect factors

Conventional bridge expansion joints have the disadvantages of easy damage and lengthy maintenance period. Polyurethane concrete, as a polymer material, is gradually being applied to the repair of expansion joints. However, polyurethane-based repair materials are susceptible to a variety of factors during the early strength-building phase. In this regard, a Polyurethane-Fly Ash Composite (PU-FAC) for rapid repair was proposed in this paper and the effects of different factors on early mechanical performance were investigated. The orthogonal test was first used to determine the optimal mixing ratio of PU-FAC. Then the effects of temperature, catalyst, and curing time on the performance of PU-FAC were investigated by temperature rise curve, maturity index, SEM, and response surface method. The results showed that temperature and catalyst at different curing times had both positive and negative effects on the failure pattern, curing rate, degree of foaming, and mechanical performance. Finally, the optimum values of temperature and catalyst were determined by gray correlation analysis as 15 °C and 0.6 %. By analyzing the effects of different factors on the performance of PU-FAC, it provides a basis for the rapid repair construction of bridge expansion joint anchorage area.

Neoantigen-specific stimulation of tumor-infiltrating lymphocytes enables effective TCR isolation and expansion while preserving stem-like memory phenotypes

BackgroundTumor-infiltrating lymphocytes (TILs) targeting neoantigens can effectively treat a selected set of metastatic solid cancers. However, harnessing TILs for cancer treatments remains challenging because neoantigen-reactive T cells are often rare...

The ongoing transformational journey of Australia’s oldest and largest oil and gas operation

For over 50 years Gippsland Basin Joint Venture (GBJV) has been producing oil and gas from the Gippsland Basin. Through hard work, challenging the status quo and innovation, the business, the operation and the people have been on a transformational journey. You may have heard about our conventional expansion opportunities, Kipper-Tuna-Turrum development and Longford Gas Conditioning Plant, but have you heard about how GBJV is progressing carbon dioxide (CO2) to sales with BOC and Air Liquide or how the team has reduced flare by 46% since 2018? Have you heard how the team increased Longford’s capacity by 11% in 2022 to deliver the highest gas production since 2017 to meet market demand. Or about how we are transforming the operation through our Gippsland Asset Streamlining Project, where we will no longer have a Crude Stabilisation Plant or a Gas Plant 1 at Longford? We continue to focus on our reliable gas operation through upcoming projects such as Hastings Generation Project, and Kipper Compression Project while also pursuing meaningful reductions in greenhouse gas emissions such as South East Australia Carbon Capture and Storage Project in the Gippsland Basin. Our transformation to a ‘Modern Australian Gas Business’ has not only meant change for our facilities but also change for our people in how we work and the culture we have built. Every day, our teams work to supply essential energy to Australian homes and businesses while also being on a transformational journey to improve the sustainability of our operation and contribute to the energy transition.

Improved therapeutic consistency and efficacy of CD317+ MSCs through stabilizing TSG6 by PTX3

BackgroundPreviously, we have demonstrated that the batch variations of human platelet lysate (conventional MSC expansion medium) induce MSC heterogeneity and therapeutic inconsistency. On the other hand, the MSCs expanded with chemical defined medium have improved therapeutic consistency.MethodsIn the current study, we studied the MSC subpopulation composition and variation in different types and batches of MSC expansion medium with scRNA-seq analysis.ResultsMSCs expanded with different batches of media have higher levels of heterogeneity from the perspective of cell subpopulation composition at transcriptome levels and therapeutic inconsistency. The CD317+ subpopulation has enhanced immune suppression activities. And the percentage of CD317+ MSCs within MSCs is tightly correlated with its immune suppression activities, and also contributes to the heterogeneity and therapeutic inconsistency of MSCs. the CD317+ MSCs have increased expression levels of PTX3, which might stabilize the TSG6 protein and improve the therapeutic effectsConclusionsThus, purifying CD317+ MSCs is one efficient strategy to reduce MSC heterogeneity and increase the therapeutic consistency of MSCs.

Investigating the Application of Smart Materials for Enhanced Maintenance of Rubber Expansion Joints in Bridge Expansion Joint Systems

In South Korea, the public infrastructure encompasses 172,111 facilities, with bridges accounting for a significant segment (totaling 34,199). These bridges undergo expansion due to traffic, vehicular loads, and temperature fluctuations. Expansion joint devices are installed to maintain vehicle stability and driving performance across expansion gaps. While these devices effectively ensure vehicular stability and performance, they do not address issues such as leakage and debris fall; therefore, rubber expansion joints should be installed. However, these rubber joints are prone to damage from various factors, resulting in secondary issues such as girder corrosion and accidents under bridges. Because of these inherent vulnerabilities, these joints require frequent replacements, making continuous bridge maintenance challenging. Therefore, this study explores the development of novel expansion joints using superelastic shape memory alloys to overcome the limitations of traditional rubber expansion joints. A comparative finite element analysis was conducted on the developed superelastic shape memory alloy and traditional rubber expansion joints. This study also assessed the long-term usability of these novel joints, particularly their ability to revert to their original shape post load removal. This research presents a promising alternative to conventional expansion joints and holds potential implications for enhancing the durability and safety of bridge infrastructure.

Dynamical behavior of water wave phenomena for the 3D fractional WBBM equations using rational sine-Gordon expansion method

To examine the dynamical behavior of travelling wave solutions of the water wave phenomenon for the family of 3D fractional Wazwaz-Benjamin-Bona-Mahony (WBBM) equations, this work employs the rational Sine-Gordon expansion (RSGE) approach based on the conformable fractional derivative. The method generalizes the well-known sine-Gordon expansion using the sine-Gordon equation as an auxiliary equation. In contrast to the conventional sine-Gordon expansion method, it takes a more general approach, a rational function rather than a polynomial one of the solutions of the auxiliary equation. The method described above is used to generate various solutions of the WBBM equations for hyperbolic functions, including soliton, singular soliton, multiple-soliton, kink, cusp, lump-kink, kink double-soliton, etc. The RSGE method contributes to our understanding of nonlinear phenomena, provides exact solutions to nonlinear equations, aids in studying solitons, advances mathematical techniques, and finds applications in various scientific and engineering disciplines. The answers are graphically shown in three-dimensional (3D) surface plots and contour plots using the MATLAB program. The resolutions of the equation, which have appropriate parameters, exhibit the absolute wave configurations in all screens. Furthermore, it can be inferred that the physical characteristics of the discovered solutions and their features may aid in our understanding of the propagation of shallow water waves in nonlinear dynamics.

A rasterized plane wave expansion method for complex 2-D phononic crystals

This paper introduces a computer image processing-based method called the rasterized plane wave expansion method (RPWEM). This method improves the conventional plane wave expansion method (CPWEM) and reduces its formula derivation cost in the case of 2-D phononic crystals with complex inclusions. In addition, for 2-D phononic crystals with arbitrary multiphase materials, this method can also simplify the calculation process. By employing the proposed RPWEM, successful calculations of band gaps are conducted for planar phononic crystals with the hexagonal unit cell as well as phononic crystals featuring integrated circuit-like structures. The results further validate the expanded applicability of the RPWEM in comparison to the CPWEM. In the end, a potential application similar to DIC (Digital Image Correlation) for predicting band structures of phononic crystals is proposed, and its feasibility is briefly validated.

Discrete Event Systems Theory for Fast Stochastic Simulation via Tree Expansion

Discrete Event Systems Theory for Fast Stochastic Simulation via Tree Expansion

Probabilistic Small Signal Stability Analysis with Wind Power Based on Maximum Entropy Theory

The probability parameters for the small signal stability in a system are studied to quantify the impact of uncertain wind power on system stability. With the increase in the scale of wind power access systems, how to more efficiently and accurately obtain the probability of small signal stability is worthy of further investigation. Therefore, this work proposes an analysis method of probabilistic small signal stability (PSSS) based on maximum entropy (ME) theory for studying power systems with uncertain wind power from doubly fed induction generators (DFIGs). Firstly, the sensitivity of the eigenvalues to the variable power is obtained by linearization. Then, when the probability characteristic for wind is known, the probability characteristic for the system critical eigenvalues is approximated using the ME method and the derived sensitivity. The proposed ME method is used in the analysis of the PSSS for power systems with different wind power penetration scales in case studies. Compared to the probability function for the eigenvalue obtained by the conventional series expansion method, the proposed method has excellent accuracy and sufficient efficiency in analysing the PSSS for a system with uncertain wind power.

Internal Model Principle-Based Extended State Observer for the Uncertain Systems with Nonconstant Disturbances

Existing traditional expansion state observers exhibit good tracking performance for constant and low-frequency disturbances. However, their ability to track non-constant disturbances such as ramp and high-frequency harmonics is inadequate. This paper proposes an extended state observer design method based on the internal model principle. This method achieves precise tracking of non-constant disturbances in the system, effectively addressing the issue of disturbance estimation errors in conventional expansion state observers. When applied to control systems, this approach significantly mitigates or suppresses system vibrations caused by non-constant disturbances, thereby enhancing control accuracy. Furthermore, it demonstrates the stability of the controlled system and the active disturbance rejection controller parameters over a wide range of variations. Simulation results indicate that the ADRC controller based on the proposed observer in this paper offers notable advantages, including high tracking accuracy, strong disturbance rejection capability, and good stability, leading to commendable control performance.