Water Absorption Time Research Articles

Utilizing diatomaceous earth (DE) as a sustainable substitute in alkali-activated cementitious materials: Performance and life cycle assessment

As the demand for alkali-activated cementitious materials (AACM) increases, reliance on blast furnace slag (BFS) raises concerns about potential shortages. This study evaluates the substitution of BFS with diatomaceous earth (DE) in AACM, using three DE types—raw (RDE), calcined (CDE), and spent (SDE)—at substitution rates of 0–30 %. The impact of these substitutions on fluidity, setting time, and compressive/flexural strength of the prepared mortar was assessed, along with an analysis of the mechanisms through hydration heat, product composition, and pore structure. Results indicate that DE, characterized by the porous structure and high content of amorphous silica, enhances early hydration, reduces fluidity, accelerates setting times, and refines pore structure, thereby improving strength. CDE, with its low organic content and large surface area, exhibited the best performance, while SDE was effective despite impurities, and RDE performed the poorest. Increasing DE substitution raised water absorption, impacting fluidity and setting times, with 20 % identified as the optimal substitution rate, balancing strength and workability. The entropy method-analytic hierarchy process (EM-AHP) confirmed this rate, with CDE as the optimal variant. Life cycle assessment (LCA) showed that while SDE reduces environmental impacts significantly, CDE achieves a greater reduction when considering both environmental and mechanical performance. In conclusion, CDE and SDE are viable BFS substitutes in AACM, offering enhanced performance and reduced environmental impacts.

Impact of spraying commercial Bentonite Nanoclay on fortification of the mortar as Nano Sprying Technique (NST) in heritages and historical buildings

Spraying Bentonite NanoClay as an innovative idea satisfied an urgent need for conservation of historical brick constructions. This research explores the application of Nanotechnology as a Nano-Geotechnics (NaG) and Nano Ground Improvement (NGI) techniques for fortifying the mortar between bricks in historical buildings against some environmental erosive factors. Bentonite Nanoparticles were selected because of their compatibility with mortar. They were applied via Nano Spray to mitigate holes and cracks caused by erosion. Various percentages of bentonite NanoClay (2–10%) Spray and the number of times to spray on the mortar were evaluated. Validation through field emission scanning electron microscopy imaging (FESEM/SEM), X-Ray differaction and Fluorescence analyses (XRD/XRF), Inductively coupled plasma optical emission spectroscopy (ICP-OES), Brunauer–Emmett–Teller (BET), porosity tests, water absorption time measurement, and weathering tests confirmed the efficacy and long-term stability of this method. The result indicated that double spraying of a 2% NanoClay solution proved most effective in reducing porosity, declining water absorption, and enhancing resistance to freezing and rain.

An experimental study on the wear performance of 3D printed polylactic acid and carbon fiber reinforced polylactic acid parts: Effect of infill rate and water absorption time

AbstractRapid prototyping, also known as additive manufacturing, is a nascent technology that is gaining traction in the context of environmental concerns and waste reduction, as well as the growing trend towards customized design. The additive manufacturing method, which has applications in diverse fields such as aviation, architecture, biomedical and automotive engineering, has also begun to be utilized in the construction of yachts and yacht hulls within the maritime industry. In this experimental study, the influences of sea water on polylactic acid (PLA) and carbon fiber reinforced polylactic acid (PLA/CF) parts manufactured at different infill rates (20%, 60% and 100%) were investigated. The parts were exposed to sea water for three different periods (1, 5, and 10 days) and subsequently subjected to wear tests. The dimensional accuracy, surface roughness, hardness, water absorption, volume loss, and friction coefficient of parts were measured and calculated. Additionally, the worn surfaces of the parts were investigated using field emission scanning electron microscope (FESEM) images. The findings indicate that PLA and PLA/CF parts can be produced with high dimensional accuracy. Furthermore, it can be reported that the water absorption of PLA/CF parts increased, particularly with an increase in the infill rate, while the volume loss decreased. Obtained results indicate the necessity of optimizing the 3D printing parameters and the relationship between the ambient conditions and the wear performance of the 3D printed parts.Highlights 3D printing is a highly promising method for the production of polymer composites. A pioneering study into the effect of infill rate and water absorption on the wear performance. Coefficient of friction values of PLA and PLA/CF parts ranged between 0.37 and 0.75. PLA/CF mostly exhibited higher volume loss than PLA with water absorption. Volume loss declines with a raise in the infill rate from 20% to 100%.

Experimental investigation on the impact of water immersion time and particle size on the ignition characteristics of coal dust

After drying, water-immersed coal is more prone to spontaneous combustion than raw coal. However, the influence mechanisms of particle size and water immersion duration on the physicochemical properties of coal dust, as well as the explosion and fire hazards of water-immersed coal dust, have not been sufficiently investigated. In this study, two particle sizes of coal dust were selected, and experiments were conducted using the Godbert-Greenwald furnace, Hartmann tube, Muffle furnace, and Fourier Transform Infrared Spectrometer. The study investigated the impact of different water immersion times, dust particle sizes, and dust concentrations on the sensitivity of coal dust fires and explosions, analyzed the process of functional group changes in coal dust particles in water and other mechanisms of transformation. The results indicated that the water immersion process increased the number of active functional groups on the surface of coal dust, significantly reducing the Minimum Ignition Temperature (MIT) and Minimum Ignition Energy (MIE) values for different samples, and also enhancing the ignition sensitivity and peak temperature of coal dust layer fires. This study contributes to a deeper understanding of the characteristics of coal dust and is of great significance for improving the prevention and control of coal dust fires and explosions.

Water-resistant properties improvement of aluminium oxide nanoparticles treated kraft paper by sparking process

This study aims to improve the hydrophobicity of non-sizing Kraft paper (KP) surfaces using nanoparticle coating through the sparking process. The aluminium oxide nanoparticles (Al2O3 NPs) were used for surface modification on KP through the sparking process, optimizing with varying sparking cycles (5–20 times), annealing temperatures (60–120 °C), and annealing times (1–3 h). Then, the Al2O3 NPs treated KP were examined by XRD, FT–IR, SEM, EDX, and AFM, respectively. The water contact angle (CA) was used to examine the water-resistant properties of the treated KP. The treated KP with varying sparking cycles up to 15 times showed higher surface coverage and enhanced fine roughness surface on the treated KP. The fine roughness surface of KP induced hydrophobicity (126° of CA) on the surface of KP at 15 sparking cycles. Similarly, the higher CA for hydrophobicity surface on treated KP from varying temperatures and times of the annealing process was demonstrated at 120° for 3 h. Therefore, the treated KP with 15 times of sparking cycle, annealing temperature at 120 °C for 3 h was defined as the optimized condition in this work. Furthermore, the developments of hydrophobicity and superhydrophobicity on the treated KP with CA at 135 and 155° were observed for the non-sizing and sizing KP, respectively. This indicated that the increased surface roughness and reduced surface energy of the treated KP simultaneously delayed the water absorption times on the KP surface. Consequently, the nano-treating of Al2O3 NPs using the sparking process shows the promising feature of inducing superhydrophobicity on the KP surface, which can produce a water-repellent corrugated box as an alternative packaging material.

Tribological behaviors and wettability evolution of phenolic resin-impregnated graphite materials under water immersion condition

This study investigated the tribological behaviors of two phenolic resin-impregnated graphite samples and one non-impregnated sample under dry and water immersion using a reciprocating testing device. The frictional configuration involved a steel hemisphere sliding against the surface of the graphite samples. The influence of water immersion time before each formal test on friction coefficients was discussed. The wettability evolution during the test processes and the difference in porosity, which could significantly affect water infiltrating into the sample matrix and frictional interfaces, were associated with the variation in tribological behaviors. The worn surface morphology and element analysis results indicated that the shallow valleys and pores on the surface of graphite were gradually filled by wear debris from both the graphite samples and the harder counterpart. Based on these experimental results, a tribological mechanism of the phenolic resin-impregnated graphite materials under water immersion was developed.

Analysis of Water Absorption on the Young’s Modulus and Damping of Sponge Gourd (Luffa cylindrica) Composites

ABSTRACT Composites reinforced with lignocellulosic fibers are attracting attention for use in several applications. This fact is directly linked to the advantages of using renewable lignocellulosic fibers. However, due to their cellulose-based structure, lignocellulosic fibers easily absorb water, which can affect the behavior of the composites. Surface treatments are used to reduce the hydrophilicity of fibers, but common surface treatments use chemicals, compromising the green approach of using lignocellulosic fibers. This work compares the water absorption behavior of sponge gourd-epoxy matrix composites with untreated and surface treated fibers. The effect of these treatments on the variation of the Young’s modulus and damping factor of the composites during the immersion time in distilled and salt water was also evaluated using the nondestructive impulse excitation test. In addition to the commonly used surface treatments (mercerization and acetylation), hornification has also been used to reduce the use of chemicals. The results obtained show that hornification is a competitive approach to reduce the water absorption of composites, being an interesting alternative to chemical surface treatments. A relationship was established between the amount of water absorbed and the variation in Young’s modulus and damping factor. Both properties stabilized when the water absorption saturation value was reached.

Influence of Water Immersion Time on Optimal Composition of Wood-Plastic Composites Using Mixture Experiment Design and Response Surface Methodology

Influence of Water Immersion Time on Optimal Composition of Wood-Plastic Composites Using Mixture Experiment Design and Response Surface Methodology

New Materials for Controlling Water Inrush and Sealing Tunnel Karst Pipes

Water inrush disasters in karst areas have caused great losses to underground engineering construction, so it is urgent to control water gushing disasters in karst pipelines. In this paper, solution polymerization is used to prepare a grouting and sealing expanded matrix material to control disasters. Noncovalent weak interactions were used to improve the surface properties of the expanded matrix material, the effects of the natural polymer content on the properties of the matrix material were studied, and a modified expanded matrix material with an optimal response rate was prepared. A cross-linked curing agent (CCA) was developed and synthesized, and a new cross-linked expansive grouting and sealing material (WIS grouting material) with various particle sizes was synthesized with noncovalent interactions such as hydrogen bonding, static electricity, van der Waals forces, etc. The results showed that a 4 % solution polymer content (accounting for the particle mass of the expanded matrix) was the optimal dosage, and the optimal ratio of the modified expansion matrix material to the crosslinking curing agent was 1:1. The early compressive strength exceeded 0.2 MPa, and the water absorption rate reached 170 times. There was a power function relationship between the water absorption rate and time, and the rate was controlled by adjusting the particle sizes. The mechanism through which the WIS grouting material underwent expansion and crosslinking was explained at the microscopic level. The gel formed in response to water resisted dispersion in dynamic water and rapidly sealed karst pipe water gushers. This paper proposes a novel approach to utilizing the expansion characteristics of polymer chemical synthetic materials for crosslinking to seal karst pipe water gushers, effectively addressing the issue of poor resistance to dynamic water dispersion in traditional grouting materials used in karst areas. These results provide a scientific basis for the development and application of new materials to control water inrush in karst pipes.

Characterization of microstructural evolution of asphalt due to water damage using atomic force microscopy

Water erosion significantly impacts the microstructure of asphalt, which in turn affects the macroscopic performance of asphalt mixtures, such as reducing the adhesion between asphalt and aggregates as well as diminishing water stability. This study utilizes atomic force microscopy (AFM) to investigate the micromorphology, surface height distribution, nanosurface roughness, and microsurface energy of asphalt under different water immersion durations. Furthermore, it considers the influence of asphalt's penetration grade, oil source, and modifiers on the evolution of its microstructure. AFM analysis reveals that, with the exception of crumb rubber modified asphalt (PJ90/CR), the quantity and area of beelike structures in the asphalt decrease with increasing water immersion time. The surface height distribution of asphalt exhibits characteristics of an approximate normal distribution, with an increase in nanoscale heights over time due to the dissolution of surface components by water and physical erosion effects. Notably, the surface height of PJ90/CR and SBS modified asphalt (PJ90/SBS) is significantly lower than that of PJ90 before and after water immersion. Water damage causes asphalt surface particles to dissolve and re-aggregate, forming distinct nano-protrusions and pits, thereby increasing the asphalt's roughness. Among them, the roughness of SK90 are generally higher than those of SK70, with the average roughness (Ra) and peak-to-valley roughness (Rt) increasing by 28.93 % and 60.56 %, respectively, before immersion. Moreover, water damage leads to a decrease in the surface energy of asphalt to varying degrees, indicating that water more easily penetrates the asphalt film through adsorption and diffusion actions, altering its microstructure and, consequently, reducing its surface energy. The variations in the microstructure of SK90, Shell90, and PJ90 under different water immersion durations highlight the significance of oil source on asphalt performance.

Using an eco-friendly cold pad-batch reduction pretreatment to improve the whiteness, hydrophilicity, and anti-shrinkage of wool fabric

The presence of cuticle is the primary problem factor contributing to felting shrinkage, hydrophobicity, and yellowness in wool fabric. Substantial disulfide bonds forming cross-links within the scale layer result in an extraordinarily dense structure. During dyeing and finishing processes, the scale layer poses a significant barrier, impeding the efficient penetration of various chemicals. To mitigate the hindrance due to disulfide bonds in the scales, this study employed a cold pad-batch (CPB) reduction pretreatment followed by H2O2 bleaching to treat woolen fabrics. The physical, chemical, and mechanical properties of the treated wool were evaluated through scanning electron microscopy (SEM), Allwörden reaction, whiteness index measurement, wettability assessment, felting properties examination, dyeing performance analysis, Raman spectroscopy, and tensile testing. The results indicated a 23.50% increase in the whiteness index with minimal damage to the strength of the fabric. Furthermore, the water absorption time decreased from 300 s to 6 s, and felting shrinkage was decreased to <10%. These findings indicate significant improvements in the hydrophilicity and anti-felting properties of the wool. Additionally, SEM and Allwörden reactions demonstrated substantial changes in the morphology and structure of the fibers after the pretreatment, corroborated by dyeing performance results. Raman spectra exhibited that the relative content of disulfide bonds within the scale layer decreased from 30.95% to 20.95%. It saved more than 20% of water consumption and 70% of energy consumption. The combination process greatly improved the properties of wool fibers without further damage to the main body.

Long-term properties evolution and life prediction of glass fiber reinforced thermoplastic bending bars exposed in concrete alkaline environment

Glass fiber reinforced polypropylene (GFRPP) bending bars have many advantages, such as high toughness, high durability, repeated molding and recycling, which can be used in concrete structures to replace steel stirrup for solving the problems of corrosion and service life. However, the changes in the properties of GFRPP bending bars during long-term use in alkaline concrete environments require further investigation. In the present study, GFRPP bending bars were immersed in alkaline solution at 20 °C, 40 °C, and 60 °C for as long as 180 d. The water absorption, hydrolysis, mechanical properties, and microscopic properties of the bending bars were evaluated to understand the long-term performance and mechanism of degradation. The bending bars had a higher saturated water absorption percentage and time along with a lower diffusion rate than the straight bars due to the presence of pores and micro-cracks formed during the bending process. The dissolution of the glass fibers in alkaline solution led to the partial mass loss of the GFRPP bars. Compared to the control, the tensile strength retention of the bending bars was 20.6%–56.0 %. The tensile failure mode changed from fiber bursting before immersion to shear fracture after immersion due to the decreased interfacial bonding strength and increased glass fiber brittleness. The primary degradation mechanisms were the etching of glass fibers, interface debonding, and increased void volume (∼23.7 %). The bending bars were more seriously eroded than the straight bars due to the twisting of the fibers and imperfect interfaces. The predicted degradation times of the GFRPP bending bars ranged from 1.7 years (Haikou) to 3.9 years (Harbin), corresponding to a stable tensile strength retention of 22.13 %. The results provide a basis for evaluating the durability and service life of GFRPP bending bars and promote the application of GFRPP composite stirrups in concrete structures.

Hydrophobic Coating of Vegetable-Tanned Leather with Dodecylamine

Vegetable-tanned leather exhibits a hydrophilic character due to the abundance of hydroxyl groups (-OH). In this study, the surface of vegetable-tanned leather was modified to become hydrophobic. The leather was coated using dodecylamine (DDA) through the padding method in the finishing process. The concentration of DDA varied from 1%, 2%, 3%, and 4% to identify the optimum concentration. The coating process was assisted by an activator, either acid or base, to improve the adhesion of DDA to leather. Uncoated vegetable-tanned leather was used as a control. The success of coating was identified using FT-IR and SEM-EDX analysis. The hydrophobicity of leather was conducted through a water resistance test. The success of coating is shown by the increase in their weight and thickness. Absorption bands of alkyl and amino groups of DDA are observed in FT-IR spectra around 1450 cm-1 and 3400 cm-1, respectively. SEM micrographs show that coated leathers have flatter surfaces as a consequence of DDA attachment on the leather surface. The water resistance test proves that the use of DDA can improve the leather hydrophobicity and enhance the water absorption time by up to 4 times. The optimum water absorption time is obtained when using 2% DDA.

Spatial Distribution and Diffusion Characterisation of Water in Coal Samples: An Experimental Study

Comprehending the water absorption process inherent to coal, including the associated spatial distribution patterns of water, proves indispensable in the design and evaluation of coal pillar dams in underground water reservoirs. To better understand this process, a series of NMR (nuclear magnetic resonance) tests were carried out on cylindrically shaped coal samples immersed in water for varying durations, with the upper and lower surfaces of the samples sealed. A method involving image digital processing and finite element simulation was used to quantitatively characterise the water absorption process, as well as the spatial distribution of water in the samples. The results showed that NMR imaging colour brightness differences were positively correlated with water content and that the wetted ring gradually increased in width as the water immersion time increased. The expectation and sum of squared deviations of the pixel greyscale values of the NMR images, which were used to characterise the water saturation and spatial distribution of the coal samples, represented positive and negative exponential functions of the water immersion time, respectively. This indicated that the water saturation gradually increased and became more uniformly distributed. Furthermore, based on the set threshold value of the target variable rate of change, the limiting expectation of the pixel greyscale values was obtained, and the limiting water absorption time of the coal sample was predicted. The water diffusion equation was then used to characterise the water absorption process of the coal samples, and a water diffusion model was developed to accurately obtain the wet ring boundary data. A reasonable value of the diffusion coefficient was determined by comparing and correcting the results of the numerical simulation and physical experiments with full consideration of the non-homogeneity of the numerical model. This water diffusion model can better characterise the water transport phenomena in the macroscopic barrier zone of coal pillar dams. Finally, the application prospects in terms of practical engineering were investigated.

Capillary water absorption and strength of solidified marine soft soil

In order to reveal the capillary water absorption properties and durability of soft soil solidified with industrial wastes, soda residue (SR), ground granulated blast furnace slag (GGBS), and carbide slag (CS) were used as solidifiers to solidify marine soil. The effects of solidifier content and water absorption path on capillary water absorption properties, strength, and microscopic mechanism were investigated through capillary water absorption, unconfined compressive strength (UCS), X-ray diffraction, and nuclear magnetic resonance tests. And the properties were compared with cement solidified soil. Results showed that capillary absorption parameters, including sorptivity coefficient, capillary coefficient, and diffusion coefficient, decreased with solidifier content and increased with water absorption times. The capillary absorption parameters of SR-GGBS-CS solidified soil were lower than those of cement solidified soil. For samples with 28d-UCS greater than 1390.9 kPa, the UCS after capillary absorption tended to increase up to 1.28 times. With increasing water absorption time, NaCl migrated upward and accumulated, accompanied by the change of hydrated products such as calcium chloroaluminate hydrate and ettringite, which contributed to a decrease in the strength of solidified soil. The carbon emission index of cement solidified soil was approximately 41 times that of SR-GGBS-CS solidified soil, and the soil with SR, GGBS, and CS content of 25%, 10%, and 4% respectively had the lowest carbon emission index.

Study on the strength deterioration characteristic and damage model of coal pillar dams with repeated water immersion in underground reservoirs

The continuous operation of coal mine underground reservoirs exposes the coal pillar dams to mining disturbances and prolonged water immersion, resulting in the deterioration of coal pillars' mechanical properties and posing a serious threat to the dam stability. To this end, coal samples from the proposed pillar dam in the 5–2 coal seam of Daliuta Mine in Shendong Mining Area were selected for conducting water absorption tests and triaxial compression tests under conditions of repeated water immersion, in order to study the deterioration of the mechanical properties and acoustic emission damage characteristic of coal samples as well as the mechanism behind the deterioration of coal samples under the water–rock interaction. The results indicated that: (1) the saturated water content of coal samples exhibited a progressive increase as the water immersion times increased, but with a diminishing rate of growth. (2) As the water immersion times increased, the compressive strength, cohesive force, and internal friction angle of coal samples gradually decreased. Notably, the deterioration effect was more pronounced in compressive strength and cohesive force, while the decline in internal friction angle was relatively minor, and the total deterioration degree and the stage deterioration degree of the above three had evident cumulativity and non-uniformity. The progressive rise in water immersion times led to a gradual attenuation of the deterioration effect. Meanwhile, the confining pressure exhibited a certain inhibitory impact on the strength deterioration of coal samples. (3) Compared to the dry coal samples, the average AE count rate of coal samples subjected to a single water immersion exhibited a significant decrease, and subsequent water immersion for two, three, and four times resulted in a very minor decrease in the average AE count rate. (4) The AE cumulative ringing counts in coal samples exhibited varying degrees of reduction as water immersion times increased. Specifically, the most significant decrease in AE cumulative ringing counts occurred after the initial water immersion, followed by a gradual decrease thereafter. The energy-releasing capacity of coal samples decreased, while their plasticity exhibited a gradual increase. (5) A damage model was developed for coal samples based on the water immersion times. The model indicated that the damage to coal samples increased as the water immersion times increased, and the damage rate gradually decreased and eventually stabilized. (6) The deterioration mechanism of coals under the water–rock interaction was explained. Through repeated water immersion, the physical, chemical, and mechanical interactions between water and coal induced alterations in the internal microstructure of coal samples, resulting in the deterioration of mechanical properties such as compressive strength, cohesive force, and internal friction angle, which was a cumulative damage process from the microscopic to the macroscopic level.

Linear regression analysis of properties related to moisture management using cotton–polyester knitted fabrics

The complex evaluation of thermo-physiological comfort for a particular garment is still challenging, as it depends on the different structural parameters and individual properties of textiles. Measurement of relevant fabric characteristics requires very specific laboratory equipment, such as an M 290 moisture management tester (SDL ATLAS) or similar. For this reason, it is obvious that there is a great demand to predict the overall moisture management capability ( OMMC) based on the individual properties that are responsible for clothing comfort and testing according to different standards rather than OMMC-specific calculation using the M 290 tester. Therefore, in this research, linear regression analysis was performed using MATLAB software to predict the OMMC for cotton–polyester fabrics knitted in two patterns, namely 1 × 1 rib and half-Milano rib, using four percentages of fibers. Water vapor permeability, water vapor resistance, water absorption capacity, water absorption time, and air permeability were used as input variables for linear regression analysis to predict the OMMC of fabrics. The performed analysis has shown that the OMMC is directly dependent on the relative water vapor permeability and air permeability, and the linear regression equation suggested in this research can predict the suitability of a textile for a particular garment concerning its moisture management behavior.

Application of Thermomyces lanuginosus polygalacturonase produced in Komagataella phaffii in biomass hydrolysis and textile bioscouring

In this work, the polygalacturonase (TL-PG1) from the thermophilic fungus Thermomyces lanuginosus was heterologously produced for the first time in the yeast Komagataella phaffii. The TL-PG1 was successfully expressed under the control of the AOX1 promoter and sequentially purified by His-tag affinity. The purified recombinant pectinase exhibited an activity of 462.6 U/mL toward polygalacturonic acid under optimal conditions (pH 6 and 55 ˚C) with a 2.83 mg/mL and 0.063 μmol/minute for Km and Vmax, respectively. When used as supplementation for biomass hydrolysis, TL-PG1 demonstrated synergy with the enzymatic cocktail Ctec3 to depolymerize orange citrus pulp, releasing 1.43 mg/mL of reducing sugar. In addition, TL-PG1 exhibited efficiency in fabric bioscouring, showing potential usage in the textile industry. Applying a protein dosage of 7 mg/mL, the time for the fabric to absorb water was 19.77 seconds (ten times faster than the control). Adding the surfactant Triton to the treatment allowed the reduction of the enzyme dosage by 50% and the water absorption time to 6.38 seconds. Altogether, this work describes a new versatile polygalacturonase from T. lanuginosus with the potential to be employed in the hydrolysis of lignocellulosic biomass and bioscouring.

The effect of parica seed water immersion time on the success of parica seed initiation (Schizolobium amazonicum Huber ex Ducke)

Parica culture has the potential to overcome problems in parica seed germination. One factor that influences the successful initiation of parica culture is the process of sterilization and pre-treatment in the form of breaking seed dormancy. This paper aims to analyze the effect of the immersion time of parica seeds on the germination rate of parica seeds. The explants used were parica seeds with a size of ± 2 cm. Seeds are given pre-treatment, the seeds are immersed in hot water at around 70°C for 10 minutes, the immersion time in hot water is 3, 6, 12, and 24 hours according to treatment. The variables observed were the first time the parica seeds germinated, the percentage of germinated seeds, the percentage of contamination (fungi, bacteria), and the percentage of browning. The results showed that the immersion time for pre-treatment affected the success of parica seed initiation, especially seed germination. The 3-hour immersion treatment used resulted in the highest germination of parica seeds (55%) and significantly differed from the germination rates in other immersion times. Based on the high germination rate and low level of contamination, this becomes prospectively to provide optimal in vitro parica germination.

Protection of N80 steel from erosion-corrosion of geothermal water by nanoparticle-modified expoxy resin coatings

In order to investigate the erosion-corrosion resistance of nano-SiO2/EP composite coating and TiO2/EP composite coating in a geothermal environment, the coatings were subjected to potentiodynamic polarization curve tests, AC impedance tests, weightlessness tests, under different immersion time in geothermal water. The micro-morphology of the coating after erosion-corrosion was observed to evaluate the protective effect of the modified EP coating on N80 steel. The result showed that the addition of nanoparticles can improve the corrosion resistance of EP coatings to a certain extent, and the optimum addition amount of nanoparticles is 3%. In geothermal water containing sand, the corrosion inhibition efficiency of EP coatings modified by nanoparticles was above 99.99% except for the 1 wt% SiO2/EP composite coating. When the nanoparticle content is 1 wt%, the protective effect of nano-SiO2/EP composite coating is better than that of TiO2/EP composite coating, but the protective effect is opposite when the nanoparticle content is 3% and 5%, respectively.