Gel Type Research Articles

Jammed Pickering Emulsion Gels.

Emulsion gels with specific rheological properties have widespread applications in foods, cosmetics, and biomedicines. However, the constructions of water-in-oil emulsion gels are still challenging, due to the limited interactions available in the continuous oil phase. Here, a versatile strategy is developed to prepare a new type of emulsion gels, called Jammed Pickering emulsion gels (JPEGs). In the JPEG system, SiO2 NPs in the oil phase serve as colloidal surfactants to stabilize water-in-oil Pickering emulsions, while positively-charged NH2-PEG-NH2 molecules in the water phase cross-link negatively-charged SiO2 NPs at the water/oil interface, making NP-stabilized water droplets hard to deform and thus jamming the emulsion system to form emulsion gels. The strategy to prepare JPEGs is versatile and applicable to diverse oil phases. The designed JPEGs possess many advantages, including good biocompatibility for widespread applications, shear-thinning rheological properties for easy processing, good stability Over a wide temperature range and Against centrifugation, good adhesion to wet tissues for tissue engineering, and well-controlled sustained release Under intestinal conditions. The developed JPEGs are demonstrated to be a promising delivery platform and the strategy to achieve JPEGs will trigger more innovations of material design.

Stabilizer Effects on the Gelation of Modified Recycled PET for 3D Printing Filament Application

This research identification gel types of the modified-recycled poly (ethylene terephthalate) (modified-rPET) filament, with and without the addition of heat stabilizer Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox®1010). This research also identifies the gel types and studies thermal behavior of the modified-rPET filaments above, by using a hot-stage microscopy, and a differential scanning calorimetry, respectively. rPET flakes were dried to deplete the moisture. Then, they were mixed with additives and heat stabilizer (Irganox®1010) at 0 and 0.5 pph, Then, they were extruded to be compound using twin screw extruder. The compounds were extruded into filament by using filament extruder. The two temperature profiles were used. The first and the second temperature profiles from the feed zone to the die zone were 275-275-275 oC and 290-290-290 oC, respectively. The extrudate of modified-rPET with and without heat stabilizer, were investigated the type of gel and the thermal behavior of the modified-rPET filament. From this preliminary experiment, it was found that the “unmelt-gel” defect was found from the modified-rPET filament, without the addition of Irganox®1010. On the other hand, the “crosslinked gel” defect was found from the modified-rPET filament, with the addition of Irganox®1010. Therefore, the addition of heat stabilizer (Irganox®1010) may cause the “crosslinked gel” significantly. Our future work, we will investigate the effect of another stabilizer and chain extenders on the gelation behavior, to complete this clarification systematically.

Determination of 42 antimicrobials in disinfection products by dispersive solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

Antimicrobials inhibit the growth and reproduction of microorganisms thereby alleviating skin and other problems caused by microorganisms. Antimicrobials are classified into different categories, including antibacterials, antifungals, and antivirals, among others, and include azoles, sulfonamides, tetracyclines, quinolones, and many other classes of synthetic and natural compound. The inappropriate or excessive use of antimicrobials can damage skin and other human organs and increase antimicrobial resistance. Relevant regulations and standards clearly state that antimicrobials are prohibited for use as ingredients in disinfection products. However, since antimicrobials enhance the disinfection or antibacterial effect of a product, with a significant short-term effect, antimicrobials are occasionally illegally added to disinfectant products, including those intended for human use. Therefore, establishing testing methods that provide technical support for enforcing regulations is an urgent objective. Herein, a method was established for the analysis of 42 antimicrobials in disinfection products, that is applicable to common types of disinfection-product matrix, including creams, gels, and aqueous solutions, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with dispersive solid phase extraction. The 42 antimicrobials comprise antibacterials, antifungals, and antivirals, and include seven sulfonamides, ten quinolones, three lincosamides, five tetracyclines, three macrolides, eight azoles, three purine nucleoside analogs, one furan, one nonpolyene antifungal, and one steroid. Briefly, 0.2 g of a sample was first dispersed in 2 mL of water and then extracted with 10 mL of 0.5% formic acid in acetonitrile, with 3 g of anhydrous Na2SO4 added to remove water. After centrifugation, 5 mL of the supernatant was cleaned using dispersive solid phase extraction with EMR-Lipid as the adsorbent. Lipids, waxes, surfactants, and moisturizing lubricants are commonly used as cream and gel matrices. Matrix substances containing long carbon chains dissolved in acetonitrile were removed using the EMR-Lipid adsorbent. Target analytes were separated on a Poroshell 120 EC-C18 analytical chromatography column (150 mm×3.0 mm, 2.7 μm), with 0.1% formic acid in acetonitrile and 0.1% formic acid aqueous solution used as mobile phases under gradient-elution conditions. The target analytes in the test solution were detected in positive ionization (ESI+) and multi-reaction-monitoring (MRM) modes. Analytes were characterized in terms of their retention times and selected ions, and quantified using the external-standard method. The main factors affecting method response, recovery, and sensitivity, such as the extraction method and solvent, purification method and adsorbent, mobile phase, and MS conditions, were examined during sample pretreatment and instrumental analysis. The 42 antimicrobials were effectively separated under the optimized experimental conditions; the target compounds exhibited linear working curves in the 0.25-5.0 mg/kg concentration range, with correlation coefficients (r) greater than 0.99. Limits of detection (LODs) for the 42 antimicrobials were determined from the signal-to-noise ratios (S/N) of their chromatographic peaks. LODs of 0.03-0.10 mg/kg were determined for the three matrices using 0.2-g samples and 10-mL test solution. Recoveries of 80.3-109.8%, with relative standard deviations (RSDs) of less than 9.8%, were obtained by determining three levels of each target analyte added to the three blank matrices; this process was repeated for six parallel samples. The developed method was used to analyze antimicrobials in commercially available disinfection products, with two sample batches testing positive. The established method is simple, accurate, precise, and suitable for the rapid screening and quantification of antimicrobials in disinfection products. This study provides powerful technical support for regulating the illegal addition of related antimicrobials to disinfection products.

Development of modular extrusion bioprinter prototype

Introduction: The aim of this work was to develop a prototype of a modular extrusion bioprinter capable of performing 2D and 3D printing with hydrogels based on sodium alginate and gelatin. Materials and methods: The bioprinter uses Cartesian coordinate system, the print head is movable in Y and Z axes, the printing platform is in X axis and equipped with cooling system. Constructs were printed with 3 types of gels: based on gelatin with the addition various concentrations of xanthan gum; based on combination of gelatin and sodium alginate; based on gelatin and xanthan gum with the addition of carbon nanotubes. Results: The constructs from various gels corresponded to the structure determined by their digital models. Conclusions: The developed system allows performing 2D and 3D printing with gels based on gelatin, sodium alginate, including those containing carbon nanotubes and/or xanthan gum for a wide range of experimental tasks.

Investigation on preparation and properties of gel type 188W/188Re generator

As one of the most important integrated nuclides for diagnosis and treatment in recent years, rhenium-188 (188Re) has a broad scope in the clinical application. Due to the specific properties of such radionuclide, it was mainly provided by the chromatographic 188W-188Re generators. There is no doubt that the application of 188Re in the treatment of various diseases depended on the development of 188W-188Re generator. Considering the high standards of such technology on radioactive activity of 188W and impurity content, a 188W-188Re generator filled with the zirconium tungstate gel has been prepared in this work. The effects of molar ratio of chemical agents, pH, reaction temperature, drying methods, rinsing methods and other conditions on the synthesis of gel particles have been studied. Furthermore, a variety of characterization techniques were used to observe the macro-/micro-morphology and chemical structure of gel particles. It can be concluded that vacuum freeze-dried method could significantly increase the specific surface area, pore size and tungsten content of gel particle. In order to decrease the content of 188W in the elute, a handful of acidic alumina was filled in the bottom of our 188W-188Re generator, an elution and purification integrated-generator was formed. During the first five processes, the nuclear purity of 188Re solution was above 99.99%, the radiochemical purity was approximately 99.5%, the pH value was 5.0–7.0 and the average elution efficiency reached up to 82.7%. In addition, the leakage rate of 188W was low as 1.60 × 10−6, and the peak of elute curve was located at 2 mL without the trailing phenomenon. This work lays a solid foundation for the domestic demand of daughter nuclide 188Re, further makes an outstanding contribution to the application of the radiation therapy technology and the protection of people's health.

Research on Efficient Electromagnetic Shielding Performance and Modulation Mechanism of Aero/Organo/Hydrogels with Gravity-Induced Asymmetric Gradient Structure.

To eliminate electromagnetic pollution, it is a challenging task to develop highly efficient electromagnetic shielding materials that integrate microwave absorption (MA) performance with high shielding capability and achieve tunability in shielding performance. Asymmetrically structured aero/organo/hydrogels with a progressively changing concentration gradient of liquid metal nanoparticles (LMNPs), induced by gravity, are prepared by integrating the conductive fillers Ti3C2Tx MXene and LMNPs into a dual-network structure composed of polyvinyl alcohol and cellulose nanofibers. Benefiting from the unique structure, which facilitates the absorption-reflection-reabsorption process of electromagnetic waves along with conductive fillers and the porous structure, three types of gels demonstrate efficient shielding performance. HPCML achieves a total shielding effectiveness (SET) of up to 86.9dB and a reflection shielding effectiveness (SER) of as low as 2.85dB. Especially, APCML, with an ultra-low reflection coefficient (R) of 6.4%, achieves compatibility between shielding performance and MA properties. The relationship between dispersing media (air, water, and glycerol/water) and the shielding performance of aero/organo/hydrogels is explored, thereby achieving modulation of the shielding performance of the gel system. The work has paved a clear path for integrating absorption and shielding capabilities into a composite material, thereby providing a prototype of a highly efficient shielding material with MA performance.

Multifunctional tri-electrode sensors for the measurement of displacement, force, and infrared irradiation

Abstract Here we described the effect of displacement, force and infrared irradiation on the resistance and impedance of tri-electrode multifunctional sensors. These sensors are based on the gel type composite of carbon nanotubes (CNT), nickel phthalocyanine (NiPc) and edible oil. The channel of this tri-electrodes (field effect transistors) structure is made of CNT-NiPc-oil gel composite using rubbing-in technology. The tri-electrode sensors’ response depends upon the direction of force/displacement and shows an anisotropy. Application of force or displacement from the top causes to decrease resistance and the impedance and vice versa in case of applying force or displacement from the side. The displacement and force sensitivities were up to -273.3 Ω/µm and -46.5 Ω/gf from the top and 480.0 Ω/µm and 3.1 x 102 Ω/gf from the side, respectively, for the sensing ranges 0-150 µm and 0-215 gf. Under the effect of the infrared irradiation from any direction the impedance and the resistance of the sensor reduces. On changing infrared irradiation intensity from 0 to 2500 W/m2 the sensitivities from top and side of the sensor were -37.4 Ωm2/W and -16.5 Ωm2/W, respectively. The investigated sensors may potentially be used as prototypes to develop gel-electronic-based shockproof sensors. The technological achievement in fabricating these devices is the consumption of environmentally friendly materials, particularly edible oil (organic). The edible oil allows to formulate uniform composite gel-films, that may not be comprehended only by ingredients mixing. The fabricated sensors are highly attractive for commercialization.

Multimodal Pilot Evaluation of a Hyaluronic Acid Infraorbital Filler Using Precise, Multi-Positional, 3D Imaging Quantification, Patient Reported Outcomes, and Anatomic Cadaveric Assessments

Abstract Background Despite the high demand of filler in the infraorbital area, there remains debate on injection practices, precise anatomical placement, and hyaluronic acid (HA) filler behavior. Objectives We aimed to contribute to the clinical and anatomic understanding of infraorbital HA injection via a prospective patient injection study in combination with a cadaveric analysis. Methods Patients were injected with Volbella XC into the tear trough region by a single experienced aesthetic plastic surgeon. Over a 90-day period, precise undereye volumetric measurements using 3D photogrammetry (VECTRA-M3) and patient reported outcomes (FACE-Q) were collected and analyzed relative to two pretreatment severity scales. Juvéderm Vycross and Restylane NASHA products were injected into the infraorbital and malar region in six cephalus specimens and evaluated with regards to the anatomic injection location with and without common clinical physical manipulations. Results Eleven patients participated with a 100% retention rate. Infraorbital HA volume maintenance was 70-81% at 30 days and 50-70% at 90 days. Significant improvement was noted in the eyes, overall facial appearance, and cheekbones (p<0.05) with FACE-Q outcomes, irrespective of pretreatment severity. In the cadaver examination, we observed differences in the anatomic locations occupied by Juvéderm and Restylane products as well as in behavior after physical manipulation between gel types. Conclusions Volbella XC effectively augments undereye volume to diminish infraorbital hollowing as measured over a 90-day period with significantly improved PROs. Enhanced knowledge of the behavior of Volbella XC and other HA fillers in this sensitive anatomic region will lead to improved patient outcomes.

Enhancing photovoltaic cell design with multilayer sequential neural networks: A study on neodymium-doped ZnO nanoparticles

Multilayer sequential neural networks, a powerful machine learning model, demonstrate the ability to learn intricate relationships between input features and desired outputs. This study focuses on employing such models to design photovoltaic cells. Specifically, neodymium (Nd)-doped ZnO nanoparticles (NPs) were utilized as a photoanode for fabricating dye-sensitized solar cells (DSSCs). A natural dye extracted from Spinacia oleracea was employed, while two types of electrolytes, liquid and gel (polyethylene glycol-based), were used for comparative analysis. Extensive material characterization of the photoanode highlights the impact of Nd content on the physicochemical properties of ZnO. Notably, when the doped photoanode and gel electrolyte were combined, a substantial 110% improvement in power conversion efficiency (PCE) was achieved. Building on these findings, the machine learning model in this research accurately predicts the current-voltage (I-V) curve values for such photoanodes, with an impressive accuracy of 98%. Additionally, the model illuminates the significance of variables like crystal distortion, texture coefficient, and doping concentration, underscoring their importance in the context of photovoltaic cell design.

Development and Performance Evaluation of a New Conformance Control Agent Gel.

How to effectively plug the multi-scale fractured water channeling has always been the key to achieving efficient water flooding of fractured low-permeability oil reservoirs. In this paper, a new type of supramolecular-polymer composite gel is developed, which is suitable for plugging multi-scale fractured water channeling. The supramolecular-polymer composite gel is composed of a polymer (such as polyacrylamide), cross-linking agent (such as polyethyleneimine), supramolecular gel factor (such as cyclodextrin) and polarity regulator (such as ethyl alcohol). The mass fraction of polyacrylamide, polyethyleneimine, cyclodextrin and ethyl alcohol are 0.15%, 0.2%, 1% and 0.2%, respectively. At the initial state, the viscosity of the composite gelant system is less than 20 mPa·s. It has good injection performance in micro-scale fractures and can enter the deep part of a fractured reservoir. At 40 °C, the composite gelant system can form a gel with a double network structure after gelation. One of the networks is formed by the covalent interaction between polyacrylamide and polyethyleneimine, the other network is formed by the self-assembly of cyclodextrins under the action of the ethyl alcohol. The comprehensive performance of the composite gel is greatly improved. The strength of the composite gel is >5 × 104 mPa·s, and it has good plugging strength in large-scale fractures. The composite gel can be used as a conformance control agent for fractured low-permeability oilfields.

Systematic screening and evaluation for an optimal adsorbent in a facade-integrated adsorption-based solar cooling system for high-rise buildings

Solar-powered adsorption chillers are a climate-friendly solution for building cooling, but costs and space requirements limit their widespread adoption. Recently developed adsorption cooling facade systems (ACFS) save installation space and further reduce CO2 emissions. The performance of ACFS depends on the implemented adsorbent. To achieve low costs and high performance of ACFS, this study systematically screened and scored adsorbents using the analytic hierarchy process (AHP) method, focusing on price, stability, driving temperature and adsorption capacity. This method narrowed down 293 adsorbents to top 10 scored adsorbents including 4 silica gels, 4 active carbons and 2 molecular sieves. The adsorbent-specific performance is evaluated by numerical simulation, revealing silica gel Type A++, Type 2560, Siogel and molecular sieve AQSOA-FAM-Z02 have peak adsorber temperatures 1.5–9.3 °C lower and increase solar cooling efficiency (SCE) by 25–27 % compared to reference adsorbent Zeolite 13X. A sensitivity analysis of the Dubinin-Astakhov equation shows increasing E and decreasing V leads to an only minor adsorber temperature decrease and minor system efficiency increase. Lower temperatures and higher capacity cannot guarantee better system performance. This underscores that improving system performance cannot be achieved solely through adsorbent optimization but requires system optimization in parallel.

Μagnet integrated fabric phase sorptive extraction (MI-FPSE) for the selective isolation of seven sulfonamides from human urine prior to HPLC-DAD analysis

In the present study magnet integrated fabric phase sorptive extraction (MI-FPSE) was employed for the selective extraction of seven sulfonamides (i.e., sulfamerazine, sulfamethazine, sulfamethoxypyridazine, sulfamonomethoxine, sulfamethoxazole, sulfisoxazole and sulfadimethoxine) from human urine prior to their determination by high pressure liquid chromatography – diode array detection (HPLC-DAD). The MI-FPSE protocol was optimized after studying the critical parameters that affect extraction, namely: type of sol–gel sorbent, extraction time, desorption time, stirring rate, type and volume of elution solvent, the ionic strength and the pH of the sample matrix using the one-factor-at-a-time method. The developed MI-FPSE-HPLC-DAD method was validated in terms of linearity, sensitivity, selectivity, accuracy, and precision and presented satisfactory results. The limits of detection (LODs) and quantification (LOQs) ranged between 0.02–0.04 ng/μL and 0.06–0.15 ng/μL, respectively. The RSD% values of the intra-day and inter-day assays were found lower than 6.7 % and 9.4 %, respectively, showing good precision. Accuracy was assessed using percentage of relative recovery and varied from 86.3–112.9 % (intra-day study) and 85.5–106.9 % (inter-day study) for all examined analytes. The green character and practicality of the proposed method were investigated using the ComplexGAPI index and Blue Applicability Grade Index (BAGI).

Preparation and Characterization of Preformed Polyelectrolyte and Polyampholyte Gel Particles for Plugging of High-Permeability Porous Media.

Excessive reservoir water poses significant challenges in the oil and gas industry by diminishing hydrocarbon recovery efficiency and generating environmental and economic complications. Conventional polymer flooding techniques, although beneficial, often prove inadequate under conditions of elevated temperature and salinity, highlighting the need for more resilient materials. In this research, two types of acrylamide-based preformed particle gels (PPGs) were synthesized, as follows: polyelectrolyte and polyampholyte. These PPGs were engineered to improve plugging efficiency and endure extreme reservoir environments. The polyelectrolyte gels were synthesized using acrylamide (AAm) and sodium acrylate (SA), while the polyampholyte gels incorporated AAm, AMPS, and APTAC, with crosslinking achieved through MBAA. The swelling properties, modulated by temperature, salinity, and pH, were evaluated using the Ritger-Peppas and Yavari-Azizian models. The mechanical characteristics and surface morphology of the gels were analyzed using SEM and BET techniques. In sand pack experiments designed to mimic high-permeability reservoirs, the inclusion of 0.5 wt.% of fine PPGs substantially reduced water permeability, outperforming traditional hydrogels. Notably, the polyampholyte PPGs demonstrated superior resilience and efficacy in plugging. However, the experiments were limited by the low test temperature (25 °C) and brine salinity (26.6 g/L). Future investigations will aim to apply these PPGs in high-temperature, fractured carbonate reservoirs.

An oil-in-gel type of organohydrogel loaded with methylprednisolone for the treatment of secondary injuries following spinal cord traumas

The secondary injuries following traumatic spinal cord injury (SCI) is a multiphasic and complex process that is difficult to treat. Although methylprednisolone (MP) is the only available pharmacological regime for SCI treatment, its efficacy remains controversial due to its very narrow therapeutic time window and safety concerns associated with high dosage. In this study, we have developed an oil-in-gel type of organohydrogel (OHG) in which the binary oleic-water phases coexist, for the local delivery of MP. This new OHG is fabricated by a glycol chitosan/oxidized hyaluronic acid hydrophilic network that is uniformly embedded with a biocompatible oil phase, and it can be effectively loaded with MP or other hydrophobic compounds. In addition to spatiotemporally control MP release, this biodegradable OHG also provides a brain tissue-mimicking scaffold that can promote tissue regeneration. OHG remarkably decreases the therapeutic dose of MP in animals and extends its treatment course over 21 d, thereby timely manipulating microglia/macrophages and their associated with signaling molecules to restore immune homeostasis, leading to a long-term functional improvement in a complete transection SCI rat model. Thus, this OHG represents a new type of gel for clinical treatment of secondary injuries in SCI.

Food Protein Nanofibril Gels: From Conditions, Types and Properties to Applications.

Many food proteins can be assembled into nanofibrils under pH conditions far from the isoelectric point and with a low ionic strength by heating them for a long period. These food protein nanofibrils (FPN) have outstanding functional and biological properties and are considered sustainable biomaterials in many fields. In this study, we review the recent developments in FPN gels and introduce the key factors in promoting food protein self-assembly in order to create functional gels. The major variables discussed are the morphology of nanofibrils, protein concentration, heating time, and the type and concentration of salts. We also highlight current advances in the formation and properties of different types of FPN gels. In addition, the various applications of FPN gels in bioactive and nutrient delivery, adsorbents for CO2 and toxic pollutants, cell scaffolding biomaterials, biosensors, and others are introduced and discussed.

Experimental Evaluation of Performance of a Low-Initial-Viscosity Gel Flooding System.

In order to effectively adjust reservoir heterogeneity and further exploit the remaining oil, a new type of low-viscosity gel was prepared by adding a regulating agent, retarder, and reinforcing agent on the basis of a polymer + Cr3+ crosslinking system. The new gel has the advantages of low initial viscosity, a slow gel formation rate, and high strength after gel formation. The effectiveness of the gel was verified through three-layer core displacement experiments, and the injection scheme was optimized by changing the slug combination of the polymer and the gel. The results showed that the gel can effectively block the high-permeability layer and adjust reservoir heterogeneity. An injection of 0.1 pore volume (PV) low-initial-viscosity gel can improve oil recovery by 5.10%. By changing the slug combination of the gel and polymer, oil recovery was further increased by 3.12% when using an injection of 0.07 PV low-initial-viscosity gel +0.2 PV high-concentration polymer +0.05 PV low-initial-viscosity gel +0.5 PV high-concentration polymer.

Mechanical properties of low calcium alkali activated binder system under ambient curing conditions

These days, the construction industry is facing sustainability issues, leading to the selection of greener, low-carbon, alkali-activated materials. This study examines a low calcium alkali activated system composed of three constituents (ceramic brick, metakaolin waste, and phosphogypsum). The AAB compositions consist of the primary precursor, waste ceramic brick, which is increasingly (20–100 wt%) replaced with waste metakaolin. The alkaline solution was made of sodium hydroxide and water; dosage depended on the Na2O/Al2O3 ratio (1.00–1.36). The AAB specimens were inspected by using XRD (X-ray diffraction) and FT-IR (Fourier transform infrared spectroscopy) methods for the evaluation of mineral composition, accompanied by SEM–EDS (scanning electron microscopy & energy dispersive X-ray spectroscopy) for the analysis of the microstructure. The compressive strength after 7, 28 and 90 days, along with water absorption and softening coefficient were determined. Also, mixture calorimetry was established. The results have shown that the initial materials are suitable for producing medium-strength alkali-activated binder under ambient temperature. The maximum compressive strength was reached by using the combination of 80% CBW and 20% MKW (13.9 and 21.2 MPa after 28 and 90 days respectively). The compressive strength development was linked with the formation N–A–S–H gel and faujasite type zeolite. A higher level of geopolymerization in composition with metakaolin waste led to lower compressive strength. Consequently, binding materials with low demand of high final and especially early compressive strength could be produced under ambient temperature curing, making them more sustainable.

Preparation and Experimental Research of Temperature Sensitive Expansion Gel Material for Fire Prevention and Extinguishing in Coal Mines

ABSTRACT In order to solve the problems of high viscosity at room temperature, easy dehydration and shrinkage of phase change gel, and poor plugging effect of traditional mine gel, a new type of temperature-sensitive expansion gel was developed by using hydroxypropyl methyl cellulose, chitosan, guar gum and sodium bicarbonate as raw materials, using orthogonal test and response surface analysis. The structural characterization, characteristics, fire prevention, and extinguishing performance of the temperature-sensitive expansion gel were tested. The experimental results show that the optimal ratio of temperature-sensitive swelling gel is 0.75 wt % chitosan, 0.5 wt % acetic acid, 2.5 wt % hydroxypropyl methyl cellulose, 0.4 wt % sodium bicarbonate, and 0.15 wt % guar gum. The phase transition temperature (LCST) of this ratio is 67°C. After standing at room temperature for 6 h, the gel viscosity is 5852 mpa·s, the expansion ratio is 0.846, and the strength is 319.525 N/m2. During the heating process of the coal sample after adding the temperature-sensitive expansion gel, the gel will undergo phase change and expansion in the high-temperature area of the coal, and the viscosity will increase. It can stay in the high-temperature area, wrap the coal block, and isolate the oxygen from entering, thus effectively inhibiting the coal spontaneous combustion process. In addition, the gel also produces inert gas carbon dioxide, which effectively suffocates the flame. Therefore, compared with the conventional inhibitor solution, the temperature-sensitive expansion gel has better fire extinguishing effect.

Growth of Romaine Lettuce in Eggshell Powder Mixed Alginate Hydrogel in an Aeroponic System for Water Conservation and Vitamin C Biofortification.

Vitamin C is crucial for physical well-being, and its deficiency can lead to severe health consequences. Biofortification has been used to address this deficiency by enhancing vitamin C in plants. Additionally, soilless agriculture has been used to conserve and optimize water use in comparison to conventional agriculture. While hydrogels have been shown to improve water conservation and are used for biofortification in crops, their application has only been explored in soil-based and hydroponic farming. The aeroponics system is a plant-growing method that has shown potential for increasing yields and biomass while conserving water and nutrients. In this paper, we have developed an aeroponic-compatible medium to grow romaine lettuce (Lactuca sativa L.) with eggshell powder (ESP) mixed with calcium-alginate hydrogel as a substrate and nutrient source aiming to conserve water and incorporate vitamin C through biofortification. Herein, lower water spray time and higher intervals, with varied gel types and ESP concentrations, resulted in healthy lettuce growth. Plants treated with 0.5% ascorbic acid-absorbed ESP-mixed alginate hydrogel for biofortification showed higher levels of vitamin C compared to the traditional method. This study suggests using an alginate hydrogel-ESP-based substrate in aeroponics to reduce water usage and enhance plant biofortification of vitamin C.

Fabrication and Application of Grinding Wheels with Soft and Hard Composite Structures for Silicon Carbide Substrate Precision Processing.

In silicon carbide processing, the surface and subsurface damage caused by fixed abrasive grinding significantly affects the allowance of the next polishing process. A novel grinding wheel with a soft and hard composite structure was fabricated for the ultra-precision processing of SiC substrates, and the grinding performance of the grinding wheel was assessed in this study. Different types of gels, heating temperatures, and composition ratios were used to fabricate the grinding wheel. The grinding performance of the grinding wheel was investigated based on the surface integrity and subsurface damage of SiC substrates. The results showed that the grinding wheel with a soft and hard composite structure was successfully fabricated using freeze-dried gel with a heating temperature of 110 °C, and the component ratio of resin to gel was 4:6. A smooth SiC substrate surface with almost no cracks was obtained after processing with the grinding wheel. The abrasive exposure height was controlled by manipulating the type and ratio of the gel. Furthermore, the cutting depth in nanoscale could be achieved by controlling the abrasive exposure height. Therefore, the fabrication and application of the grinding wheels with soft and hard composite structures is important for the ultra-precision processing of large-size SiC substrates.