Stable Rheological Properties Research Articles

Gelation Behavior and Drug Sustained-Release Properties of a Helix Peptide Organohydrogel with pH Responsiveness.

Based on the typical similar repeat units (abcdefg)n of α-helical structure, the peptide H was designed to self-assemble into an organohydrogel in response to pH. Depending on the different pH, the proportions of secondary structure, microstructure, and mechanical properties of the gel were investigated. Circular dichroism (CD) and Fourier transform infrared (FT-IR) showed that the proportion of α-helical structure gradually increased to become dominant with the increase of pH. Combining transmission electron microscopy (TEM) and atomic force microscopy (AFM), it was found that the increase of the ordered α-helix structure promoted fiber formation. The further increase in pH changed the intermolecular forces, resulting in an increase in the α-helix content and the enhancement of helix-helix interaction, causing the gel fibers to converge into thicker and more dense ones. The temperature test showed the stable rheological properties of the organohydrogel between 20-60 °C. Drug release and cytotoxicity showed that the DOX-loaded organohydrogel could have a better release in an acidic environment, indicating its potential application as a drug local delivery carrier.

Modulating macrophage phenotype for accelerated wound healing with chlorogenic acid-loaded nanocomposite hydrogel

Wound healing involves distinct phases, including hemostasis, inflammation, proliferation, and remodeling, which is a complex and dynamic process. Conventional preparations often fail to meet multiple demands and provide prompt information about wound status. Here, a pH/ROS dual-responsive hydrogel (OHA-PP@Z-CA@EGF) was constructed based on oxidized hyaluronic acid (OHA), phenylboronic acid-grafted ε-polylysine (PP), chlorogenic acid (CA)-loaded ZIF-8 (Z-CA), and epidermal growth factor (EGF), which possesses intrinsic antibacterial, antioxidant, and angiogenic capacities. Due to the Schiff base and Phenylboronate ester bonds, the hydrogel exhibited excellent mechanical properties, strong adhesion, good biodegradability, high biocompatibility, stable rheological properties, and self-healing ability. Moreover, introducing Z-CA as an initiator and nanofiller led to the additional cross-linking of hydrogel through coordination bonds, which further improved the mechanical properties and antioxidant capabilities. Bleeding models of liver and tail amputations demonstrated rapid hemostatic properties of the hydrogel. Besides, the hydrogel regulated macrophage phenotypes via the NF-κB/JAK-STAT pathways, relieved oxidative stress, promoted cell migration and angiogenesis, and accelerated diabetic wound healing. The hydrogel also enabled real-time monitoring of the wound healing stages by colorimetric detection. This multifunctional hydrogel opens new avenues for the treatment and management of full-thickness diabetic wounds.

A rapid-floating natural polysaccharide gel–raft with double-effect for the treatment of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal condition characterized by regurgitating stomach contents into the esophagus, causing mucosal damage or erosion. Clinical physical protection treatment mainly relies on the use of floating rafts. Bletilla striata (BS) is widely regarded as the first-choice drug for treating digestive tract injuries in Chinese Medicine. The rapid-floating gel-raft (B-R) was prepared via a one-step swelling method using natural BS polysaccharide and glyceryl monooleate. Panax notoginseng saponins (PNS) were loaded to further prepare P/B-R according to clinical experience. Possessing hydrophobic dense, stratified porous structure and stable rheological properties, an outperforming floating performance of P/B-R was proven compared with Gaviscon® (alginate-antacid formulation) in vitro. In vivo imaging results showed that P/B-R can retain and adhere to the gastric mucosa of rats for up to 90 min, protecting and repairing the mucosa. Besides physical protection in situ, the systemic effects of antioxidant and anti-inflammatory actions for treating GERD were achieved through the intestinal release of PNS. Acid-labile PNS was protected by P/B-R against gastric acid, attaining the desired release and permeability. A significantly effective mucosa injury protective effect of P/B-R was found in ethanol-induced gastric damage model on rats. Moreover, P/B-R exhibits excellent biosafety at the cellular level.

Stability of Viscoelastic Solutions: BrijL4 and Sodium Cholate Mixtures with Metal Ions Across a Broad pH and Temperature Range.

The impact of pH, temperature, and metal ions on the rheological and interfacial properties of aqueous mixed surfactant solutions composed of anionic NaC (sodium cholate) and nonionic BrijL4 [polyoxyethylene (4) lauryl ether] surfactants has been investigated. The various compound systems were analyzed, considering variations in each selected factor. The results highlight the unique characteristics of the BrijL4/NaC mixture, suggesting its potential as a viable alternative to other existing surfactants. The synergistic effect between BrijL4 and NaC significantly reduces the critical micelle concentration (CMC) and improves the wetting properties on hydrophobic surfaces, surpassing those of single-component solutions. Additionally, sodium, calcium, and magnesium ions enhance surface wetting and decrease the CMC. Besides, the BrijL4/NaC solutions exhibit viscoelastic fluid behavior at higher surfactant concentrations. These viscoelastic BrijL4/NaC solutions demonstrate stability over various pH and temperature variations, exhibiting lower flow activation and scission energy values than those of other viscoelastic surfactant solutions. Notably, the BrijL4/NaC mixture has potential applications in gel-based foliar fertilizers and drug delivery systems. Furthermore, the rheological studies examine the impact of humic acid on the rheological properties of BrijL4/NaC mixture solutions, revealing that incorporating additional humic acids can achieve stable rheological properties.

An ECM-mimicking assembled gelatin/hyaluronic acid hydrogel with antibacterial and radical scavenging functions for accelerating open wound healing

A multifunctional hydrogel dressing with hemostatic, antibacterial, and reactive oxygen species (ROS)-removing properties is highly desirable for the clinical treatment of open wounds. Although many wound dressings have been prepared, the modification of polymers is often involved in the preparation process, and the uncertainty of biological safety and stability of modified polymers hinders the clinical application of products. In this study, inspired by the composition and crosslinking pattern of extracellular matrix (ECM), a deeply ECM-mimicking multifunctional hydrogel dressing is created. Tannic acid (TA) and poly-ϵ-lysine (EPL) are added into a gelatin/hyaluronic acid (Gel/HA) matrix, and a stable hydrogel is formed due to the formation of the triple helix bundles of gelatin and hydrogen bonds between polymers. The introduction of TA and EPL endows the ECM-mimicking hydrogel with stable rheological properties, as well as antibacterial and hemostatic functions. The as-produced hydrogels have suitable swelling ratio, enzyme degradability, and good biocompatibility. In addition, it also shows a significant ability to eliminate ROS, which is confirmed by the elimination of 2,2-diphenyl-1-picrylhydrazyl free radical. Full-thickness skin wound repair experiment and histological analysis of the healing site in mice demonstrate that the developed ECM-mimicking Gel/HA hydrogels have a prominent effect on ECM formation and promotion of wound closure. Taken together, these findings suggest that the multifunctional hydrogels deeply mimicking the ECM are promising candidates for the clinical treatment of open wounds.

Effect of calcium alginate/collagen hydrolysates beads encapsulating high-content tea polyphenols on quality characteristics of set yogurt during cold storage

High-content tea polyphenols (TPs) are necessary for the functional and health-related properties, but precipitate milk proteins to prevent milk from fermenting into yogurt. In this study, calcium alginate/collagen hydrolysates beads encapsulating high-content TPs (CA/CHBs-e-HCTPs) were prepared and added at 0 (control), 5, 10 or 15 (g/100 g) to milk to produce fortified set yogurt and stored at 4 °C for 7 days. The results showed the encapsulation efficiency of TPs in CA/CHBs-e-HCTPs was 91.58 % (103 mg TP/g beads), resulting in a maximum TPs content of 1545 mg/100 g of set yogurt that still gave yogurt stable rheological properties and good water holding capacity, as well as significantly enhancement in antioxidant properties during cold storage when the addition of CA/CHBs-e-HCTPs increased from 0 to 15 (g/100 g). Moreover, after fermentation and storage, CA/CHBs-e-HCTPs swelled by 10% that equipped with stable texture, and TPs released from CA/CHBs-e-HCTPs was <6.42%. FTIR and SEM results revealed the stable intertwined interactions between TPs and wall materials. In conclusion, the CA/CHBs-e-HCTPs could effectively alleviate the precipitate of milk proteins to ferment into fortified set yogurt and played an important role in enhancing the nutritional and functional values of yogurt by high-content TPs.

Fast‐setting mineral‐impregnated carbon‐fiber (MCF) reinforcements based on geopolymers

AbstractMineral‐impregnated carbon‐fiber (MCF) reinforcements are an innovative type of fiber‐reinforced composites, which combine the valuable properties of high‐performance fibers with durable inorganic matrix materials. The application of mineral‐based matrices to produce MCFs offers a wide range of advantages, such as high resistance to elevated temperatures, low cost, adequate physical and chemical bond with concrete substrates and high technological flexibility in automated processing. In particular, specific‐designed geopolymer (GP) impregnation suspensions allow stable rheological properties with a sufficient long‐lasting processing window as well as moderate curing temperatures to accelerate a fast setting on demand ‐ similar to organic based thermosets. The paper at hand studies the effect of various thermal curing regimes of a GP impregnation matrix and for the forming process of the resulting MCF composite. The fabrication of MCFs were performed by using commercially available raw materials and a continuous pultrusion line with subsequent oven heating at 50 °C and 75 °C. A wide range of experimental investigations at multiple scales have been performed to understand the GP matrix development, fiber‐matrix interface and final MCF properties.

Chitin nanofibers prepared by enzymatic hydrolysis: Characterization and application for Pickering emulsions

Chitin nanofibers (ChNFs) have a wide range of applications in numerous fields owing to their exceptional material properties and biological functionality. This research focused on producing ChNFs with diameters of 20–70 nm using chitinase and ultrasound from crayfish shells. The impact of enzymatic duration on ChNF yield and performance was investigated. Results revealed ChNFs forming a high aspect ratio network structure. Chitinase hydrolysis enhanced ChNF dispersion and yield while improving crystallinity and thermal stability without significantly altering their chemical structure. Enzymatically modified ChNF suspensions also exhibited stable rheological properties. Moreover, ChNFs showed good emulsification and emulsion stability in Pickering emulsion. The mechanism may be the effective adsorption of ChNFs at the oil-water interface, and the formation of a ChNF network in the continuous phase that prevents droplet coalescence. This study highlights that the potential of chitinase and ultrasound for the production of ChNFs and the utilization of crayfish shell waste.

Novel polymeric organic gelator as lost circulation material for oil-based drilling fluids

With the exploitation of unconventional oil and gas resources towards deep and ultra-deep formations, oil-based drilling fluids (OBDFs) with white oil as a base oil have been increasingly employed in China to achieve safe, efficient, and fast drilling operations. However, due to the lack of effective lost circulation material (LCM), drilling time and drilling fluids are severely delayed and extra consumed, respectively. Herein, we innovatively propose and successfully develop a polymeric organic gelator using an emulsifier-free emulsion polymerization method and find that it achieves remarkable plugging ability in OBDF, superior to commercial LCMs, including asphalt, fine calcium carbonate, elastic graphite, and rubber particles. In detail, SMHDV with a branched C8 pendant group, benzene ring, isopropyl, and acetate groups is homogeneously dispersed in OBDF after hot rolling and capable of blocking permeable porous formations, resulting in a reduction of the cumulative filtration by 68 % at a concentration as low as 1 wt%. When added at a high concentration above 10 wt%, SMHDV turned into an organogel which can block cracks and prevent severe lost circulations together with other bridging materials. Furthermore, SMHDV maintains considerable plugging capacity in a wide temperature range of 80–150 °C, which meets most requirements of oil wells. The superior performance is attributed to the formation of supramolecular network structure in white oil due to the self-assembly behavior, which originated from the appropriate hierarchical polarities. In addition, the material can maintain stable rheological properties after hot rolling, improving the electrical stability of the drilling fluid. It is expected to form a set of scientific and efficient OBDF plugging technology to solve the leakage problems encountered during drilling.

Development and characterization of novel Lycium barbarum seed oil-based oleogels and their application in functional chocolate

The shortage of cocoa butter (CB) resources has limited the growth of the chocolate industry, and the use of oleogels as a substitute for CB is an emerging strategy. Glycerol monostearate beeswax complex oleogels (GBO), glycerol monostearate rice bran wax complex oleogels (GRO) and glycerol monostearate lacquer wax complex oleogels (GLO) were prepared by using Lycium barbarum seed oil as the base oil with wax. The feasibility of these three oleogels for partial replacement of CB in chocolate was also investigated. The resulting oleogels were characterized using texture profile analysis (TPA), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and rheology. The results showed that all three oleogels were hydrogen bonded and had similar polycrystalline properties. Among the three oleogels, GRO showed the highest hardness and oil binding capacity (OBC) of 1457 g and 99.82%, respectively. And it showed the best gelation properties in 1–100 Hz and 0.001–10% strain sweep. The oleogel chocolates were characterized by rheology, crystal polymorphism and sensory properties. Compared to the control group without oleogels, GRO showed the best substitution, with GRO-chocolate having more stable rheological properties, better taste and overall acceptability. This study provides new ideas for the preparation of chocolates that are lower in saturated fatty acids and richer in nutrients.

Injectable multifunctional hydrogel based on carboxymethylcellulose/polyacrylamide/polydopamine containing vitamin C and curcumin promoted full-thickness burn regeneration

Burn injuries are a major global problem, with a high risk of infection and mortality. This study aimed to develop an injectable hydrogel for wound dressings, composed of sodium carboxymethylcellulose/polyacrylamide/polydopamine containing vitamin C (CMC/PAAm/PDA VitC) for its antioxidant and antibacterial properties. Simultaneously, silk fibroin/alginate nanoparticles (SF/SANPs) loaded with curcumin (SF/SANPs CUR) were incorporated into the hydrogel to enhance wound regeneration and reduce bacterial infection. The hydrogels were fully characterized and tested in vitro and in preclinical rat models for biocompatibility, drug release, and wound healing efficacy. Results showed stable rheological properties, appropriate swelling and degradation ratios, gelation time, porosity, and free radical scavenging capacity. Biocompatibility was confirmed through MTT, lactate dehydrogenase, and apoptosis evaluations. Hydrogels containing curcumin demonstrated antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). In the preclinical study, hydrogels containing both drugs showed superior support for full-thickness burn regeneration, with improved wound closure, re-epithelialization, and collagen expression. The hydrogels also showed neovascularization and anti-inflammatory effects, as confirmed by CD31 and TNF-α markers. In conclusion, these dual drug-delivery hydrogels showed significant potential as wound dressings for full-thickness wounds.

Development and Characterizations of Novel Aqueous-Based Ceramic Inks for Inkjet Printing.

Stable rheological properties of ceramic ink are a key requirement for inkjet printing (IJP), which should be satisfied in terms of the Reynolds and Weber numbers. In this paper, the reverse microemulsion was introduced for the synthesis of monodispersed nanosized ceramic powders, and the average size was less than 100 nm. A comparison of two different dispersants, i.e., polyacrylic ammonium (PAANH4) and polyacrylic aid (PAA), revealed that the former exerted a good dispersion effect on the ceramic ink. The sedimentation ratio, zeta potential, surface tension, viscosity, and density of the inks were measured, and the Reynolds and Weber numbers, as well as Z value, were calculated. A stable, homogeneous, and high solid loading (20 wt%) ceramic ink could be achieved after aging for a period of 72 h. Finally, the ceramic inks showed the desired printable property in the inkjet printing process. Combining inkjet printing technology with a sintering process, Ni-Mn-O films have the potential to monitor temperature and humidity parameters for intelligent wearable devices.

Technology Focus: Drilling and Completion Fluids (November 2022)

As the oil and gas drilling industry moves into more technically challenging environments [e.g., drilling ultradeep onshore/offshore wells under extremely high temperature (above 300°F) and pressure (mud specific gravity above 2.0)], companies increasingly come under pressure to stretch technology and improve drilling performance while continuously striving to reduce costs and meet the requirements of stricter environmental regulations. Significant reserves additions may be realized if the risks associated with drilling in such harsh conditions (e.g., pressure control, wellbore instability, lost-circulation, sour gas) can be managed effectively. Design and development of a new generation of drilling fluids able to fulfill all of the attributed functions (e.g., stabilize the wellbore, control formation pressure, transport the drilled cuttings, minimize the fluid loss, and not reduce formation productivity) under such extreme pressure and temperature conditions is one of the key requirements for unlocking these resources. Drilling fluids used under ultrahigh pressures and temperatures need to be thermally stable and able to retain their rheological properties. Traditionally, nonaqueous drilling fluids (NADFs) have been used under these extreme conditions. NADFs, however, have significantly high operational costs with an associated health, safety, and environmental risk. As a result, there has been an increasing demand from operators to use aqueous drilling fluids [water-based muds (WBMs)], which are known to be environmentally benign and relatively less expensive. The use of WBMs under extreme temperatures and pressures, however, faces several challenges, including the breakdown of polymers and other additives used as fluid-loss preventers and rheological stabilizers. Therefore, recent research has focused on design and development of WBM systems meeting the following specifications: - Use of sodium chloride (for barite-laden formulation) and sodium bromide (for barite-free formulation) as base brines to reduce the total solids content for optimal fluid properties and to maximize the quality of wireline logs - Ensure inhibition of reactive shale formations to maintain wellbore stability while drilling intermediate sections - Provide optimal and stable rheological properties for excellent hole cleaning and drilling performance The newly developed ultrahigh-temperature water-based systems used custom-made branched synthetic polymers that exhibit superior rheological properties and fluid-loss control as well as long-term stability above 400°F. These branched synthetic polymers are compatible with most oilfield brines and maintain excellent low-end rheology. Other formulations proposed the use of β-cyclodextrin polymer microspheres (β-CPMs) as an environmentally friendly ultrahigh-temperature filtration reducer. When the temperature rose above 160°C, a hydrothermal reaction occurred for β-CPMs, and, as a result, numerous micro- and nanosized carbon spheres formed, which bridged across micro- and nanopores within the filter cake and reduced the filter cake permeability effectively. Bentonite-hydrothermal carbon nanocomposites also are proposed as nonpolymer additives to solve the ultrahigh-temperature/-pressure challenge in water-based drilling fluid. The nanocomposites are synthesized by a simple hydrothermal reaction in which biomass starch and sodium bentonite are used as the precursor and template, respectively. Such formulations have shown favorable rheology and filtration properties after hot rolling at temperatures as high as 460°F. This section presents selected papers showing examples of design, development, and field applications of the new generation of WBM fluid technologies. Recommended additional reading at OnePetro: www.onepetro.org SPE 206444 - Successful Application of a New Generation of Clay-Inhibitor Polymers While Drilling a Deep Exploration Well in the Astrakhan Region by Petr Leonidovich Ryabtsev, Akros, et al. SPE 205539 - Improvement of Rheological and Filtration Properties of Water-Based Drilling Fluids Using Bentonite-Hydrothermal Carbon Nanocomposites Under Ultrahigh-Temperature and High-Pressure Conditions by Hanyi Zhong, China University of Petroleum East China, et al. SPE 209805 - The Utilization of Self-Crosslinkable Nanoparticles as a High-Temperature Plugging Agent in Water-Based Drilling Fluid by Ming Lei, University of Alberta, et al.

The Design of Rapid Self-Healing Alginate Hydrogel with Dendritic Crosslinking Network.

Self-healing alginate hydrogels play important roles in the biological field due to their biocompatibility and ability to recover after cracking. One of the primary targets for researchers in this field is to increase the self-healing speed. Sodium alginate was oxidized, generating aldehyde groups on the chains, which were then crosslinked by poly(amino) amine (PAMAM) via Schiff base reaction. The dendritic structure was introduced to the alginate hydrogel in this work, which was supposed to promote intermolecular interactions and accelerate the self-healing process. Results showed that the hydrogel (ADA-PAMAM) formed a gel within 2.5 min with stable rheological properties. Within 25 min, the hydrogel recovered under room temperature. Furthermore, the aldehyde degree of alginate dialdehyde with a different oxidation degree was characterized through gel permeation chromatograph aligned with multi-angle laser light scattering and ultraviolet (UV) absorption. The chemical structure of the hydrogel was characterized through Fourier transform infrared spectroscopy and UV-vis spectra. The SEM and laser scanning confocal microscope (CLSM) presented the antibiotic ability of ADA-PAMAM against both S. aureus and E. coli when incubated with 10-7 CFU microorganism under room temperature for 2 h. This work presented a strategy to promote the self-healing of hydrogel through forming a dendritic dynamic crosslinking network.

Application of W/O Drilling Fluid in Horizontal Well with Long Horizontal Sections in Oil Shale Formations

To address the challenges of oil shale formation well wall instability,micro and nano pore blocking, long horizontal section well friction and borehole purification.We have analysed the nature of formation lithology,matrix pore size and specific surface by using linear expansion method,rolling recovery method and nuclear magnetic resonance method,and developed a white W/O drilling fluid system with an oil-to-water ratio of 70:30 by developing emulsifiers,tackifying and shear strength-improving agents,plugging agents and preferably filter loss agents,and wetting agents.The system was evaluated by using the breakthrough pressure test triaxial compression test and relaxation measurement method in the laboratory. The evaluation results showed that the system could not only maintain the strength of the rock sample but also improve the plasticity of the rock sample after the drilling fluid soaked with the breakthrough pressure of 6.5MPa,and it had good suspension capacity after the relaxation value reached 60s.The field test results show that the system has stable rheological properties and solves the problems of well wall instability and borehole purification,with the well diameter expansion rate of only 3.8% and the mechanical drilling speed of up to 10.85m/h.The SY-1 well has set a record for the longest horizontal section of 1800m in the Liaohe River oil area.

A Composite Hydrogel Containing Mesoporous Silica Nanoparticles Loaded With Artemisia argyi Extract for Improving Chronic Wound Healing.

Chronic wounds are a major health problem with increasing global prevalence, which endangers the physical and mental health of those affected and is a heavy burden to healthcare providers. Artemisia argyi extract (AE) has excellent antibacterial and anti-inflammatory properties. In this research, we developed AE loaded composite hydrogel scaffold based on methacrylate gelatin (GelMA)/methacrylate hyaluronic acid (HAMA) and mesoporous silica nanoparticle (MSN) as sustained-release drug carrier vehicles for the treatment of chronic wounds. The presented GelMA/1%HAMA hydrogel possessed stable rheological properties, suitable mechanical properties, appropriate biodegradability, swelling, sustained-release AE capacity. In vitro antibacterial and cell experiments showed that the GelMA/HAMA/MSN@AE hydrogel had excellent antibacterial activity and biocompatibility and induced macrophages to differentiate into M2 phenotype. In vivo wound healing of rat full-thickness cutaneous wounds further demonstrated that the prepared GelMA/HAMA/MSN@AE hydrogel could significantly promote chronic wound healing by upregulating the expression of IL-4, TGF-β1, CD31, and α-SMA but downregulating the expression of TNF-α and IFN-γ and promoting M1-M2 macrophages polarization. Altogether, we believe that the GelMA/HAMA/MSN@AE hydrogel will have wide application prospects in healing chronic wounds.

Comprehensive evaluation of self-healing polyampholyte gel particles for the severe leakoff control of drilling fluids

Lost circulation has been a serious problem to be solved in many drilling practices during oil, gas and geothermal well drillings. Many materials have been developed and evaluated for the purpose. However, their performance to plug severe leakoff is very limited. Herein, an injectable self-healing hydrogel based on polyampholyte with sulfonated and quaternary ammonium functionalities (P(MPTC-co-NaSS)) was developed and comprehensively evaluated to prevent the severe loss of fluids to formation. By incorporating cation-π (π is for aromatic residues) interaction, the hydrogel shown self-healing property and robustness in severe environment (temperature, salt) by comparison with other hydrogels merely consisting of cation-anion and H-bonding interactions. Aromatic residues enhanced thermal stability above 310 °C. The plugging measurement shown that an addition of 2 wt% dried gel particles can plug high-permeability formation and endure a high pressure of 6 MPa, produce much lower circulation loss and result in a dramatically increased loss volume reduction rate (63.5%) compared with a commercial polymer gel product and an inert material (9.4%) after a self-healing process. Markedly, P(MPTC-co-NaSS) can be used in a wide range of formation temperature (as high as 150 °C) and salt concentrations (NaCl, CaCl2, as high as 15 wt %). In addition to suitable particle size and mechanically robustness, it was also attributed to the soft, swelling, deformable, toughness and self-healable features of P(MPTC-co-NaSS) gel particles as well as the strong adhesion to negatively charged formations in water, even under high thermal and saline condition. These characteristics also contributed to a long-term plugging performance, beneficial to avoid repeated lost circulation in drilling operation. Besides, this self-healing polyampholyte gel particles dispersed well in saline fluid and maintained stable rheological properties after hot rolling, which was favorable to drilling fluid circulation. This study shown the application potential of self-healing materials as plugging material candidate in petroleum drilling industry.

Relationship of erythrocyte adrenoreactivity with their quantitative and qualitative characteristics as a method for assessing the rheological properties of blood in athletes

Objective of the study: prediction of the rheological properties of blood in young men with different levels of motor activity (MA) by assessing the relationship between the adrenergic reactivity of erythrocytes (ARE) with their quantitative and qualitative parameters.Materials and methods: the study involved young men with a low (41 people) and a high level of physical activity (athletes — 20 people), aged 21–23 years. In all subjects, the total, individual characteristics of erythrocytes and ARE were determined. ERS was assessed by the change in the erythrocyte sedimentation rate (ESR) under the influence of adrenaline in vitro at final concentrations of 10–5; 10–6; 10–7; 10–8; 10–9; 10–11; 10–13 g/ml venous blood. According to the nature of the observed effect, in accordance with the direction of ESR shifts, 3 types of ARE were distinguished: increased ESR in the presence of adrenaline — aggregative (Ar, type 1); no changes — areactive (Ap, type 2); decreased ESR — antiaggregatory (AnAg, type 3).Results: in athletes, inverse correlations of the ARE types were established when exposed to stress concentrations of adrenaline (SCA) (above 10–8 g/ml) with the hemoglobin level (r = –0.59, p = 0.008), the average hemoglobin content in the erythrocyte (r = –0.55, p = 0.016), when exposed to physiological concentrations of adrenaline (PCA) (10–9 g/ml and below) — with the corpuscular volume of erythrocytes (r = –0.51, p = 0.029). In young men with a low level of MA, an inverse correlation was found between the minimum ARE values and the number of erythrocytes (r = –0.36, p = 0.01), and the maximum — with the average concentration of hemoglobin in the cell (r = 0.54, p = 0.04).Conclusion: in young men leading a sedentary lifestyle, the tendency of erythrocytes to aggregate under the influence of adrenaline increases with an increase in their number and intracellular viscosity. In athletes, the predominance of the antiaggregatory type of ARE, and, consequently, more stable rheological properties of erythrocytes and an improvement in microcirculation, are facilitated by a decrease in the size of erythrocytes and an average saturation of cells with hemoglobin.

Ultralow emission micro-printing process for PET fibers using liquid disperse dye

The commercial powder disperse dye used for printing polyester fabrics exhibits many environmentally-unfriendly properties, especially the associated high wastewater emission. In this study, three kinds of liquid disperse dyes (C.I. Disperse Blue 291:1, (L-DB); C.I. Disperse Red 179, (L-DR), and C.I. Disperse Orange 30, (L-DO)), two kinds of binders (A and/or B), and a micro-printing process, were applied to polyester fabric, with the goal of reducing freshwater consumption while maintaining color fastness. The influences of rheological and printing performance and color fastness were studied. Home-made liquid dyes of L-DB, L-DR and L-DO were found to exhibit higher color depth, excellent color fastness, and ultralow emission of wastewater and waste residual during the micro-printing process. The binder comprised of silicone-modified polyacrylate was observed to increase dye uptake, reduce dye sublimation, and improve color fastness. The liquid dyes of L-DB, L-DR and L-DO also exhibit stable and better rheological properties, which appeared to have little effect on the viscosity of printing pastes when compared with commercial powder disperse dye of Blue 3GFL (C.I. Disperse Blue 291:1), Red 2B (C.I. Disperse Red 179) and Yellow brown S-4RL (C.I. Disperse Orange 30), respectively. Results of this micro-printing process indicated that it is an environmentally clean production technology.

Nanomaterials Modified Drilling Fluid for Improving Deep Drilling Conditions

Abstract Achieving stability of drilling fluids (DFs) rheology with high temperature and high pressure (HTHP) has always seen a growing focus with increasing pursuits of deep drilling operations to maximize hydrocarbon recovery. Since there is no boundary of how deep the drilling technology can be pushed to access deep-lying reservoirs, the quest to improve and stabilize the drilling fluids rheology is an open-ended and ongoing matter. This paper presents an investigation of two distinct clays namely sepiolite (SP) and attapulgite (AT) in nanoform as water-based drilling fluid (WBDF) additives for improved and stable rheological properties. The process of material sourcing, characterization, development in nanoform, and testing as a drilling fluid additive at low and high temperature and pressure conditions are the main focus of this study. Through experiments, it was determined that 30–60 nm size range and 4 wt% concentration of developed nanomaterials yielded the optimal performance. Various tests were then performed at HTHP, and the stability of nanosepiolite (NSP) and nanoattapulgite (NAT) in 4 wt% concentration was compared with regular drilling fluid additive (bdf403) which is used as a common rheology stabilizer in the industry. It was found that for NSP and NAT-modified drilling fluids, the yield point, plastic viscosity, and gel strength were found to be retained at temperatures and pressures of up to 180 °C and 15 ksi, respectively, in contrast to bdf403 WBDF which deteriorated at much lower temperature and pressure. NSP additives were found to be more effective than NAT additives. The results confirmed a strong dependence of the DF stability on the morphological characteristics of the tested clays, implying that the properties of the DFs can be tailored by modifying the clay morphologies, particularly in the nanoform.