Reservoir Solution Research Articles

Hybrid cooling and heating absorption heat pump cycle with thermal energy storage

This study presents a hybrid cooling/heating absorption heat pump with thermal energy storage. This system consists of low- and high-pressure absorber/evaporator pairs, using H2O/LiBr as the working fluid, and it is driven by low-temperature heat source of 80 °C to supply cooling and heating effects simultaneously. Using solution and refrigerant reservoirs, the system can store thermal energy in the form of chemical potential owing to the concentration glide. Applying the building cooling/heating temperature conditions, the operating concentration range of the system is constrained to 0.49–0.59 LiBr mass fraction. In this range, a system performance analysis is conducted through simulation modeling. The maximum total COP of the hybrid heat pump cycle reaches 0.80, which is same as the maximum COP of the single-effect absorption chiller with the same operating conditions. In storage mode, the maximum total COP is reduced to 0.30 due to the lack of internal heat recovery, while a maximum energy storage density (ESD) of 402.4 kJ/kg is achieved. In particular, the performance of the storage mode is dominantly affected by the solution circulation ratio, indicating the design criteria for the proposed system.

Mitigation of Gravity Segregation by Foam to Enhance Sweep Efficiency

Foam-assisted gas injection exhibits promising potential for enhancing sweep efficiency through the amelioration of gravity segregation, particularly within reservoirs characterized by heterogeneity. In this work, the implicit-texture (IT) model featuring two flow regimes is employed to examine the impact of heterogeneity on gravity segregation. The validation of the numerical results for water–gas coinjection and pre-generated foam injection is accomplished through a comparative analysis with analytical solutions. A hypothetical two-layer model with varying permeabilities and thickness ratios is used to examine the impact of foam on gravity segregation. The numerical findings demonstrate satisfactory conformity with analytical solutions in homogeneous reservoirs. A high-permeability top layer in a layered model with a fixed injection rate results in sweep efficiency similar to that of a homogeneous reservoir with each individual permeability. A low-permeability top layer could increase the sweep efficiency, but with severe permeability contrast, the bottom high-permeability layer could impact the displacement process, even with a thin thickness. The sweep efficiency increases with the thickness of the high-permeability top layer and decreases with a thicker low-permeability top layer under fixed injection pressure. The predicted segregation length through a single-layer approximation cannot match the results of the layered models where the permeability contrast is too great or the thickness of two layers is comparable.

Study on Residual Oil Distribution Law during the Depletion Production and Water Flooding Stages in the Fault-Karst Carbonate Reservoirs

The fault-karst carbonate reservoir is a new type of deep carbonate oil and gas resource and a target for exploration and development. The distribution of remaining oil in this kind of oilfield is very complicated because of its unique reservoir characteristics of vertical migration and accumulation, segmented accumulation, and differential accumulation. Therefore, the S91 reservoir block, a typical fracture-vuggy carbonate reservoir in the Tahe oilfield, was taken as the object of this research. According to the development characteristics as well as the porosity and permeability characteristics of the fracture-vuggy, the reservoirs were divided into three types: cave, pore, and fracture. A numerical simulation model of the fracture-vuggy reservoir of the S91 unit was established, and the historical fitting accuracy with dynamic production data was more than 90%. Then, the distribution characteristics of the remaining oil in the depletion stage of the fault-karst carbonate reservoir were further studied and based on the analysis of the reservoir water-flood flow line, the remaining oil distribution characteristics in the depletion stage of the fault solution reservoir were revealed. The results show that the remaining oil distribution patterns during the depletion production stage can be divided into three types: attic type, bottom water coning type, bottom water running type. Due to the serious problem of the bottom aquifer lifting caused by the reservoir development, the residual oil between wells was relatively abundant during the depletion production stage. According to the simulation results, the remaining oil distribution modes in the water drive development stage were identified as three types: sweeping the middle between wells, bottom water connection and circulation, and oil separation through high-permeability channels. In addition, the reservoir connectivity was the main controlling factor for the remaining oil distribution in the fault-karst carbonate reservoir.

Equilibration of precipitants in a counter-diffusion apparatus for protein crystallization.

A cost-effective capillary dialysis apparatus (Toledo Capillary Box, TCB) developed for biomacromolecule crystal growth in microgravity and unit gravity environments can provide slow equilibration between the precipitant reservoir and capillary solutions, nurturing growth of neutron-diffraction-quality crystals. Under microgravity conditions, mass transfer of precipitants and biomacro-mol-ecules occurs under diffusion-controlled conditions, promoting slow growth and suppressing defect formation. The equilibration of common precipitants (polyethyl-ene glycol and salts such as ammonium sulfate) between capillary and reservoir solutions was measured for capillaries oriented horizontally or vertically with respect to the gravitational field at unit gravity. Precipitants equilibrated less rapidly in the vertical orientation when capillary solution densities were lower than those of the reservoir solutions. A plug filled with agarose gel was introduced in the TCB apparatus for salt precipitants since salts often exhibit relatively high free diffusion. Equilibration of the capillaries with reservoir solutions was significantly delayed for many of the salt precipitants tested. Analytical and semi-analytical models allow the prediction of precipitant equilibration of capillary and reservoir solutions under diffusion-controlled transport and show good agreement with experimental results.

Description of a Nonhuman Primate Model of Retinal Ischemia/Reperfusion Injury.

To establish an inducible model of retinal ischemia/reperfusion injury (RI/RI) in nonhuman primates (NHPs) to improve our understanding of the disease conditions and evaluate treatment interventions in humans. We cannulated the right eye of rhesus macaques with a needle attached to a normal saline solution reservoir at up to 1.9 m above the eye level that resulted in high intraocular pressure of over 100 mm Hg for 90 minutes. Retinal morphology and function were monitored before and after RI/RI over two months by fundus photography, optical coherence tomography, electroretinography, and visual evoked potential. Terminal experiments involved immunostaining for retinal ganglion cell marker Brn3a, glial fibrillary acidic protein, and quantitative polymerase chain reaction to assess retinal inflammatory biomarkers. We observed significant and progressive declines in retinal and retinal nerve fiber layer thickness in the affected eye after RI/RI. We noted significant reductions in amplitudes of electroretinography a-wave, b-wave, and visual evoked potential N2-P2, with minimal recovery at 63 days after injury. Terminal experiments conducted two months after injury revealed ∼73% loss of retinal ganglion cells and a fivefold increase in glial fibrillary acid protein immunofluorescence intensity compared to the uninjured eyes. We observed marked increases in tumor necrosis factor-alpha, interferon-gamma, interleukin-1beta, and inducible nitric oxide synthase in the injured retinas. The results demonstrated that the pathophysiology observed in the NHP model of RI/RI is comparable to that of human diseases and suggest that the NHP model may serve as a valuable tool for translating interventions into viable treatment approaches. The model serves as a useful platform to study potential interventions and treatments for RI/RI or blinding retinal diseases.

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials

A novel semi-analytical model for transient pressure behavior in fracture-cave carbonate reservoirs

Fracture-cave carbonate reservoirs represent a significant amount of oil and gas resources worldwide, while their intrinsic complex pore network, large caves and tectonic fractures bring challenges to reservoir characterizations and productions. Many models have been proposed to solve the pressure transient analysis (PTA) solutions for such reservoirs. With recent explorations, the position of fractures and caves can be determined by seismic data. However, models using the position information with the coexistence of discrete fractures and caves were not reported in the literature. This paper proposes a novel semi-analytical model based on the Boundary Element Method (BEM), to describe the transient pressure behavior of the fracture-cave carbonate reservoirs. Basically, the proposed model treats the cave edge as an inner boundary and includes the fracture-cave fluid interchanges. As a results, the model's solution is proved to be flexible for arbitrary cave and reservoir shape. A typical system consisting of one fracture and one case is discussed in detail. The result indicates the well location is the key factor to the pressure response, where the pressure response is mostly affected by the cave volume and fracture conductivity when the well is on the cave and fracture, respectively. The sensitivities of three major parameters on the pressure response are analyzed. In addition, the proposed model is applied in two field cases. The result shows the proposed model is reliable and accurate.

Effects of Vermicompost and Beneficial Microbes on Biomass and Nutrient Density in Purple Lady Bok Choy (Brassica rapa var. chinensis) in A Vertical Hydroponic Grow Tower System

Indoor food production in vertical hydroponic systems can be done year-round in any climate, has less negative environmental impacts compared to industrial agriculture and is a way of increasing the nutritional value of crops. Indoor hydroponic systems make it easy to control the precision of additives and amendments, such as fertilizers and vermicompost tea, to nutrient solution reservoirs. Vermicompost tea is known to contain beneficial microorganisms and can help increase the biomass, nutrient density, and overall health of the plants. Microorganisms and plants have co-evolved and is an essential relationship that deserves recognition and further research. The goal of the research presented in this paper was to better understand if vermicompost tea and its associated microorganisms, such as bacteria, fungi, nematodes, and protozoa, would increase biomass and nutrient density of Purple Lady Bok Choy (Brassica rapa var. chinensis) in vertical hydroponic systems. Statistical analyses were performed to compare the biomass and macro- and micronutrients of three different treatments to one another and a control. There was a significant difference between the mean leaf and root biomass among varying concentrations of vermicompost tea solutions and added inorganic hydroponic fertilizer. The nutrient density for both macro- and micronutrients also differed significantly due to different concentrations of vermicompost tea, suggesting that beneficial microbes may help plants uptake and absorb nutrients in a more efficient manner depending on the concentration of vermicompost tea and hydroponic fertilizer.

Calibration of a novel rebound tonometer (Tono-Vera® vet) in the porcine eye.

Porcine models of ocular disease are becoming increasingly utilized. A recently commercialized ocular tonometer, the Reichert Tono-Vera® Vet, has not been evaluated for use in pigs. The purpose of this study was to calibrate this device for use in porcine eyes and to determine which settings are most appropriate for use in pigs. The anterior chambers of five freshly enucleated normal porcine eyes were cannulated then connected to a reservoir of balanced salt solution and a physiologic monitor. Triplicate measurements were obtained with the four available settings: dog, cat, horse, and rabbit at intraocular pressures ranging from 5- to 80 mmHg. Bland-Altman analysis was utilized to determine bias and 95% limits of agreement for each setting. There was a strong positive linear regression trend for all settings (dog r2 =0.986, horse r2 =0.947, cat r2 =0.977, and rabbit r2 =0.982). The linear regression equations for the dog, horse, cat, and rabbit setting were y=1.0168x - 2.6128, y=0.8743x - 3.4959, y=0.9394x - 7.3188, and y=1.1082x - 3.4077. The average bias and 95% limits of agreement for dog, horse, cat, and rabbit settings were - 2.00, -8.32, -9.58, and 0.57 mmHg, and (-7.52, 3.53), (-19.00, 2.37), (-16.66, -2.50), and (-7.79, 8.93), in mmHg. The Tono-Vera® Vet dog setting was most accurate and precise setting compared to true intraocular pressures. This setting is likely to be appropriate for in vivo use in pigs, with the appropriate correction formula applied.

An experimental methodology to assess the impact of desaturation on gas diffusion in clay based materials

The transport of gas in clay-based materials is dominated by diffusion. SCK CEN has studied and recorded an extensive data set of diffusion coefficients of gases in various saturated clays (Boom Clay, Opalinus Clay, Callovo-Oxfordian claystone and bentonites) used in Europe as host formations or in engineered barrier systems in the context of deep geological disposal of high and intermediate level nuclear wastes. However, partially saturated conditions may exist during the life cycle of a radioactive waste repository. The current study aims at establishing an experimental method to measure the diffusion coefficients of various gases in partially saturated clay-based materials by means of double through diffusion tests (cross diffusion of gases across the porous sample, driven by concentration gradients) and to assess the impact of desaturation on gas diffusivity. Historically, gas diffusion measurements have been performed under dissolved conditions with continuous water and dissolved gas flow around the clay sample. However, since the saturation degree of the sample has to be constant, a novel setup has been designed and optimized to operate under a pure gas phase under controlled relative humidity (RH). The experimental concept consists of cross diffusion of gas mixtures from two reservoirs at a fixed relative humidity on either side of the sample cell, namely, the upstream and downstream reservoirs. The RH is controlled using the same saturated salt solutions in both reservoirs. During the experiment, gases will diffuse from the upstream to the downstream reservoir. By measuring the change in gas composition in the downstream reservoir with a gas analyzer equipped with a mass spectrometer (which expresses the gas composition in terms of partial pressure), the gas flux and hence the diffusion coefficient is estimated by applying steady state Fick’s first law. The experimental methodology has been validated by performing an experiment on a sandy-clay sample of known petrophysical properties, at full saturation.

Structure Determination of SH2-Phosphopeptide Complexes by X-Ray Crystallography: The Example of p120RasGAP.

The p120RasGAP protein contains two Src homology 2 (SH2) domains, each with phosphotyrosine-binding activity. We describe the crystallization of the isolated and purified p120RasGAP SH2 domains with phosphopeptides derived from a binding partner protein, p190RhoGAP. Purified recombinant SH2 domain protein is mixed with synthetic phosphopeptide at a stoichiometric ratio to form the complex in vitro. Crystallization is then achieved by the hanging drop vapor diffusion method over specific reservoir solutions that yield single macromolecular co-crystals containing SH2 domain protein and phosphopeptide. This protocol yields suitable crystals for X-ray diffraction studies, and our recent X-ray crystallography studies of the two SH2 domains of p120RasGAP demonstrate that the N-terminal SH2 domain binds phosphopeptide in a canonical interaction. In contrast, the C-terminal SH2 domain binds phosphopeptide via a unique atypical binding mode. The crystallographic studies for p120RasGAP illustrate that although the three-dimensional structure of SH2 domains and the molecular details of their binding to phosphotyrosine peptides are well defined, careful structural analysis can continue to yield new molecular-level insights.

Three-electrode cell calorimeter for electrical double layer capacitors.

A calorimeter was built to measure the heat from a porous capacitive working electrode connected in a three-electrode configuration. This makes it possible to detect differences between cathodic and anodic heat production. The electrochemical cell contains a large electrolyte solution reservoir, ensuring a constant concentration of the salt solution probed by the reference electrode via a Luggin tube. A heat flux sensor is used to detect the heat, and its calibration as a gauge of the total amount of heat produced by the electrode is done based on the net electrical work performed on the working electrode during a full charging-discharging cycle. In principle, from the measured heat and the electrical work, the change in the internal energy of the working electrode can be determined as a function of the applied potential. Such measurements inform about the potential energy and average electric potential of ions inside the pores, giving insight into the electrical double layer inside electrode micropores. Example measurements of the heat are shown for porous carbon electrodes in an aqueous salt solution.

Water Desalination Using Polyelectrolyte Hydrogel: Gibbs Ensemble Modeling.

Polyelectrolyte hydrogels can absorb a large amount of water across an osmotic membrane as a result of their swelling pressure. On the other hand, the insoluble cross-linked hydrogel network enables dewatering under the influence of external (thermal and/or mechanical) stimuli. Moreover, from a thermodynamic perspective, a polyelectrolyte hydrogel is already an osmotic membrane. These properties designate hydrogels as excellent candidates for use in desalination, at the same time avoiding the use of expensive membranes. In this article, we present our recent theoretical study of polyelectrolyte hydrogel usage for water desalination. Employing a coarse-grained model and the Gibbs ensemble, we modeled the thermodynamic equilibrium between the coexisting gel phase and the supernate aqueous salt solution phase. We performed a sequence of step-by-step hydrogel swellings and compressions in open and closed systems, i.e., in equilibrium with a large and with a comparably small reservoir of aqueous solution. The swelling in an open system removes ions from the large reservoir, whereas the compression in a closed system decreases the salt concentration in the small reservoir. We modeled this stepwise process of continuous decrease of water salinity from seawater up to freshwater concentrations and estimated the energy cost of the process to be comparable to that of reverse osmosis.

MASR: A novel monitoring method coupled with interpretation platform for near-term management in thermal stratified reservoirs

Good water quality is critical to public health and aquatic ecological security of global reservoirs. In stratified reservoirs, increasing near-term management demands foster extremely high monitoring and forecasting needs. In this study, a management assistant for stratified reservoirs (MASR) was developed, including a wave-driven monitoring platform and interpretation platform for multiple reservoir water quality variables. The wave-driven platform can adapt to the characteristics of water level changes and transmit the monitoring data through a mobile network to the reservoir manager, which are processed by the interpretation platform in real time for near-term management. After several months of application, MASR monitored 1237 groups of valid profile water quality data with an acceptable error, which showed a strong capacity for capturing the water quality dynamics in a stratified reservoir. The effective identification of thermal stratification structures and anoxic zones can help managers to design withdrawal schemes for reservoirs. Moreover, the prediction of algae state based on the back propagation (BP) neural network provided the basis for making operation plans to proactively control algae blooms. Our study provides an economical and convenient solution for stratified reservoirs to address near-term management issues.

Salt Partitioning in Cationic Thermoresponsive Hydrogels for Model‐Seawater Desalination

AbstractCharged hydrogels partially reject salt ions during swelling in a salt solution reservoir. This feature suggests applicability for the separation of salt ions from saline water for water desalination in a membrane‐free forward osmosis process. In this work, model charged cationic and thermoresponsive hydrogels are prepared and their potential for desalination of model seawater containing both monovalent and divalent ions with concentrations of 0.11–3.5 wt% is investigated. The recovery of adsorbed water, after partial salt rejection, is achieved by heating the hydrogels. The salt rejection increases upon increase of the charge density of the hydrogels and diminishes by increase of the concentration of the salt solution. In addition, the salt rejection during deswelling of the hydrogels is in the opposite of the overall process target, adding another challenge on the efficiency of the approach. Besides the experimental results, equations based on the Donnan theory are derived to predict the salt rejection of hydrogels during swelling and deswelling processes. While the theoretical values deviate from the experimental ones, the theory predict the overall trend well. Both experimental and theoretical results confirm that this approach has considerable potential for the desalination of saline water at low concentrations such as brackish waters.

Computational modeling of corneal and scleral collagen photocrosslinking

Scleral photocrosslinking is increasingly investigated for treatment of myopia and glaucoma. In this study a computational model was developed to predict crosslinking efficiency of visible/near infrared photosensitizers in the sclera. Photocrosslinking was validated against riboflavin corneal crosslinking experimental studies and subsequently modeled for the sensitizer, methylene blue, administered by retrobulbar injection to the posterior sclera and irradiated with a transpupillary light beam. Optimal ranges were determined for treatment parameters including light intensity, methylene blue concentration, injection volume, and inspired oxygen concentration. Additionally, sensitivity of crosslinking to various parameters was quantified. The most sensitive parameters were oxygen concentration in the injection solution, scleral thickness, and injection reservoir thickness (i.e., injection volume).

Development of a low-cost iot platform for data collection

Precision agriculture in the Internet of Things (IoT) integrates different technologies able to raise crop productivity, optimize resource efficiency, and accelerate decision making. However, the adoption of this technology is usually costly, affecting the acquisition by the farmers. Thus, the objective of this work was to develop and evaluate low-cost hardware to obtain data in a hydroponic system via IoT. The experiment was conducted at the Pici Campus of the Federal University of Ceará and split into three distinct stages. Firstly, the DS18B20 temperature sensors were calibrated in water, using the KR380 infrared thermometer as a comparison method. For the second step, when the hydroponic system was installed, the water temperature was monitored in the channel and not in the solution reservoir. In this same phase, the quality of data sending and receiving was investigated. In the third step, the sensory data were analyzed with those obtained by the local Meteorological Station. The calibration results revealed that the DS18B20 sensor has reasonable accuracy and excellent agreement and reliability between data. As for receiving and storing, only 6% of the total data was lost.

Analytical Time-Dependent Shape Factor for Counter-Current Imbibition in Fractal Fractured Reservoirs

Summary The fluid exchange behavior for counter-current imbibition in fractured reservoirs can be quantitatively characterized by the transfer function in numerical simulation. The time-dependent shape factor (TDSF) in the transfer function is one of the main factors controlling fluid transport, which directly affects the result of ultimate oil recovery prediction. In practice, fractured reservoirs with different microscopic pore structures often have varied flow laws under the same flow conditions. However, the current TDSFs proposed for counter-current imbibition assume that the microscopic pore structure has no impact on the fluid inter-porosity flow behavior, which is inconsistent with the actual situation. In this work, the fractal theory is used to establish the TDSF of counter-current imbibition, which is related to the microscopic pore structure. First, the analytical solutions of average water saturation and imbibition rate are obtained under different conditions related to the maximum pore diameter and tortuosity fractal dimension of the matrix. The validity of the new analytical solution for strong water-wet and moderate water-wet reservoirs is ascertained by a single-porosity model and experimental data. Subsequently, the proposed analytical solution is applied to the two-phase transfer function to develop the new TDSF for counter-current imbibition, and the sensitivity analysis is carried out. The results demonstrate that the unsteady-state duration of the TDSF is proportional to the characteristic length and tortuosity fractal dimension of the matrix, and it is negatively proportional to the maximum pore diameter of the matrix. The influence of the characteristic length, tortuosity fractal dimension, and maximum pore diameter of the matrix on a constant shape factor (SF) under quasi-steady-state is exactly the opposite. This work provides an enhanced clarification of the fluid exchange behavior of counter-current imbibition in strong water-wet and moderate water-wet fractured reservoirs.

Mechanisms of water block removal by surfactant micellar solutions in low permeability reservoirs

The existing researches on surfactant micellar solutions mainly focus on the formulation optimization and core flooding test, and the types and mechanisms of cleanup additives suitable for low permeability reservoir remain unclear. The flowback efficiencies of different types of surfactant micellar solutions were evaluated by core experiments, a multi-level pore-throat system micromodel characterizing pore-throat structures of low permeability reservoir was made, and flooding and flowback experiments of brine and surfactant micellar solutions of different salinities were conducted with the micromodel to show the oil flowback process in micron pores under the effect of surfactant micellar solution visually and reveal the mechanisms of enhancing displacement and flowback efficiency of surfactant micellar solution. During the displacement and flowback of brine and low salinity surfactant micellar solution, many small droplets were produced, when the small droplets passed through pore-throats, huge percolation resistance was created due to Jamin’s effect, leading to the rise of displacement and flowback pressure differences and the drop of flowback efficiency. The surfactant micellar solutions with critical salinity and optimal salinity that were miscible with crude oil to form Winsor III micro-emulsion didnot produce mass small droplets, so they could effectively reduce percolation resistance and enhance oil displacement and flowback efficiency.

Water Gonioscopy: A Technique for Intraoperative Visualization of the Anterior Chamber Angle.

Aim and objectiveTo describe a technique of lens-free gonioscopy that allows the anterior chamber angle to be visualized intraoperatively, without the use of a gonioscopy lens.BackgroundMinimally invasive glaucoma surgery (MIGS) is an increasingly popular treatment option for mild to moderate glaucoma. We describe a technique of lens-free gonioscopy that allows visualization of the anterior chamber angle without the use of a lens. This simple intraoperative technique may be used to inspect the placement of MIGS devices within the angle.TechniqueTo perform a water gonioscopy, the surgeon sits temporal to the eye. The patient's head is turned 20–45° away from the surgeon, and the operating microscope is tilted 15–30° toward the surgeon. A reservoir of balanced salt solution is allowed to collect in the crater formed by the nose bridge and the bony orbital rim, external to the corneal surface. This body of liquid obliterates the cornea–air interface and hence allows visualization of the anterior chamber. In contrast to gonioscopy using a gonioscopy lens, water gonioscopy offers a lower magnification, ultra-wide field of view for angle visualization.ConclusionWater gonioscopy is a useful technique that anterior segment surgeons might use for quick visualization of the anterior chamber angle without the need for additional equipment.Clinical significanceThis is a simple technique that surgeons can use to visualize the anterior chamber angles intraoperatively. It is especially useful for MIGS that are placed within the anterior chamber angle, but this technique may also be used during other anterior segment surgeries, such as visualizing the haptics of an anterior chamber intraocular lens or checking for retained lens fragments in the anterior chamber angles.How to cite this articleChiam N, Perara S. Water Gonioscopy: A Technique for Intraoperative Visualization of the Anterior Chamber Angle. J Curr Glaucoma Pract 2021;15(3):106–108.