Effects Of Different Contents Research Articles

Effect of Different Content of CeO2 on the Evaluation of Micro-Structure and Wear Data of Boride Layer of Iron Based Powder Metallurgy Materials

Iron base powder metallurgy sample was borided with different content of CeO2 (0 wt.%, 2 wt.%, 4 wt.%) at 950 °C for 5 h by using solid powder boriding method. The wear tests were carried out on the friction and wear tester model MPX-3G. Scanning electron microscope (SEM), X-ray diffraction analysis, Rockwell hardness tester model Huayin HR-150A and three-dimensional non-contact tester model ST400 were used in the evaluation of micro-structure and wear data. The results show that samples with best performance in the evaluation of micro-structure and wear tests were borided with 2% CeO2.

Determination of flammability indicators of multicomponent biofuel in diesel

The object of research — multicomponent biofuel compositions, including 15 and 25 % rapeseed oil and ethanol, up to 100 % diesel fuel: MCBFC-15, MCBFC-25. The research objective is to study the effect of different content of rapeseed oil and ethanol additives in the MCBFC on their flammability indicators. The purpose of the study is the analytical determination of the cetane number and the ignition delay period in a diesel engine during its operation on MCBFC-15, MCBFC-25. Research methods — empirical analysis and generalization, development of a mathematical model. Keywords diesel fuel, rapeseed oil, ethanol, multicomponent biofuel composition (MCBFC), cetane number, ignition delay period

Determination of rational regulations of diesel engine fuel supply equipment when working on biomineral fuel mixtures

The object of research is an experimental installation consisting of a D-245.5S2 diesel engine and a RAPIDO SAK N670 electric brake stand for operation on pure diesel fuel and on multicomponent biomineral fuel mixtures (BMFM): BMFM-10, BMFM-25. The research objective is to study the effect of different content of additives of Barbarйa vulgбris oil and ethanol in BMFM on effective and toxic indicators. The purpose of the study is to determine the rational adjustments of the fuel pump YAZDA-773-40.28 diesel D-245.5S2 when it is operated on BMFM-10, BMFM-25. Research methods — experimental testing by conducting bench tests according to GOST 18509—88. Keywords fuel injection pump, setting angle of fuel injection advance, Barbarйa vulgбris oil, ethanol, diesel fuel, biomineral fuel mixture (BMFM), effective indicators, environmental indicators

Preparation of lightweight polycarbonate composite foams with robust hollow glass microspheres via CO2 foaming

AbstractPolycarbonate (PC) composites are often used in the production of high value‐added products, but it is necessary to improve its environment stress cracking condition in the presence of pre‐strain and soluble solvents. In this work, the effect of weight reduction and strengthening is realized by introducing microstructures and hollow glass microspheres (HGMs) into the PC composites. It is found that the addition of HGMs can reduce the melt viscosity and Tg value of the composite materials, which will change the foaming behavior of PC/HGMs composites. Besides, the effect of different content of HGMS and foaming temperature on the foaming behavior of PC/HGMs composite foams are studied. The PC/HGMs composite foams exhibit a typical structure of both large and small cellular pores, because of the existence of hollow beads and cellular structures. Moreover, compared to the neat PC foam, the tensile strength as well as the flexural strength of the composite foams are significantly increased by 110.9% and 364.7%, respectively. Furthermore, the as‐prepared PC/HGMs composite foams have low thermal conductivity (lower than 0.07 W/mK), which can effectively insulate heat propagation.Highlights Hollow glass microsphere can reduce melt viscosity and Tg of composites. The mechanical properties of composite foams have been greatly improved. Composite foams exhibit excellent thermal stability due to their microstructure.

Effects of nano-SiO2 additives on carbon fiber-reinforced fly ash–slag geopolymer composites performance: Workability, mechanical properties, and microstructure

Abstract Fly ash and slag are commonly used precursors in alkali-activated concrete. However, they suffer from high brittleness, poor toughness, and susceptibility to cracking. To address these limitations, this experimental study investigates the effects of different contents of nano-silica (SiO2) additives on the workability, mechanical properties, and microstructure of carbon fiber-reinforced fly ash–slag geopolymer composites (CFSGs). The results indicate that owing to its large specific surface area, nano-SiO2 significantly increases the water demand of the geopolymer, thereby considerably decreasing the fluidity and shortening the setting time of the geopolymer. However, nano-SiO2 improves the porosity, water absorption, and mechanical properties of the CFSG. The optimal mechanical strength is obtained by using 2% nano-SiO2. In addition, appropriate nanodoping can relatively improve the bearing capacity and fracture toughness of the specimen. Compared with that of undoped CFSG, the peak load, fracture toughness, unstable fracture toughness, and elastic modulus of the 2%-SiO2-doped CFSG increased by 8.78, 5.0, 9.6, and 9.8%, respectively. The incorporation of nano-SiO2 increases the shrinkage of the geopolymer, with a more significant impact on early shrinkage. Moreover, nano-SiO2 improves the microstructure of the cement matrix and interface through the filling, volcanic ash, and crystal nucleus effects as well as interface regulation. This increases the bonding force between the matrix and carbon fibers (CFs), which results in good bonding between the CFs and geopolymer matrix, accelerated geopolymerization reaction, and denser geopolymer paste, thus improving the mechanical strength of the CFSG.

Effect of Different Contents of 63s Bioglass on the Performance of Bioglass-PCL Composite Bone Scaffolds

Bioactive glasses (BG), notably 63s BG, possess distinct properties such as biodegradability, biocompatibility, and the ability to boost cellular interactions. Our research concentrated on formulating polycaprolactone (PCL) porous scaffolds enriched with 63s BG to gauge their combined mechanical and biological potentials. Using twin-screw extrusion, we created composites containing 5%, 10%, and 20% 63s BG. These were transformed into cylindrical scaffolds using 3D printing. Our assessments involved melt flow, SEM, XRD, water contact angle metrics, DSC, and extracorporeal degradation. After co-culturing with MC3T3-E1 cells, an uptick in alkaline phosphatase activity was noted. Preliminary findings demonstrated that as 63s BG content increased, the properties of the composites improved. Yet, they fell short of replicating the mechanical nuances of cortical bone, rendering them inapt for load-bearing orthopedic applications but suitable for mending minor bone defects or cartilage. In summary, while 63s BG brings about significant advancements in scaffold attributes, attaining the mechanical traits ideal for certain medical purposes remains elusive. This investigation offers foundational insights for the evolution of optimized bone tissue engineering materials.

Effect of humic acid and fulvic acid on mechanical and durability properties of geopolymer stabilized soft soil

Geopolymer with eco-friendly and excellent performance is regarded as a new generation of soil stabilizer. Although geopolymer is effective in improving the mechanical and durability properties of soft soil, the mechanism of the influence of organic matter (humic acid and fulvic acid) in soft soil is often neglected. Therefore, in this work, the effects of different contents (0%, 0.5%, 1.5%, 2.5%, 3.5%, 4.5%, 5.5%) of humic acid and fulvic acid on the mechanical and durability properties of geopolymer stabilized soft soil (GSSS) were elucidated. The mechanical characteristics, durability and microstructure of GSSS were characterized by UCS test, sulphate solution attack test, XRD and SEM analysis. The samples for the UCS test were cured in a standard curing box (temperature regulated at 20 ± 2 ℃ and humidity not less than 95%) for 7 d/28 d, while the samples for the sulphate solution attack test were cured in a standard curing box for 28 d beforehand. The results demonstrated that there existed a limit content (4.5% and 3.5%) for the effect of humic acid and fulvic acid on the UCS of GSSS, respectively, beyond which the UCS of GSSS almost ceased to change with the increase of humic acid and fulvic acid contents. With the increase of organic matter content, the damage mode of GSSS changed from brittle damage to plastic damage accompanied by the decrease of peak stress. After exposure to Na2SO4 solution, the UCS deterioration rate of GSSS incorporated with fulvic acid was faster compared to humic acid when the organic matter content did not exceed 2.5%, while the opposite was true when the organic matter content exceeded 2.5%.

Thermal decomposition characteristics and spontaneous combustion phenomenon of emulsion explosive containing FeS2 impurity

AbstractIn the process of pyrite blasting mining, emulsion explosives in blast holes can sometimes spontaneously detonate prematurely. In order to reveal its accidental explosion mechanism, the effects of different content of FeS2 impurity on the thermal decomposition characteristics and thermal spontaneous combustion parameters of emulsion explosives were studied in detail. The experimental results of thermal analysis showed that pure emulsion explosive had a strong stability, but when it was doped with FeS2 impurity, its initial temperature of thermal decomposition reaction reduced and the decomposition rate accelerated. With the increase of FeS2 impurity content, the average activation energy of emulsion explosives decomposition decreased from 110.84 to 63.78 kJ/mol, resulting in an increasing risk of thermal runaway. The results of thermal spontaneous combustion experiments showed that FeS2 impurity would significantly shorten the ignition delay period and combustion flame duration of emulsion explosive, and increase the combustion flame temperature. With the increase of FeS2 impurity content in emulsion explosive, the ignition delay period and the duration of the flame continued to decrease and increase, respectively, and the maximum average temperature of the flame showed a trend of rising at first and then decreasing. The research results were of great significance to the accident identification of emulsion explosive accidental explosion in pyrite blasting operations.

Study on the influence of different contents of impure CaO on the process of electromelting magnesia

PurposeThe aim of this study is to report the effect of different content of calcium oxide on the process of electromelting magnesia.Design/methodology/approachThe process of molten magnesia was analyzed by finite element simulation and proved by scanning electron microscope.FindingsThe results show that with the increase of CaO content, the maximum temperature appreciation increases from 3,616°C To 3,729°C, showing an approximate nonlinear evolution. Low thermal conductivity and low specific heat of CaO result in higher temperature. With the increase of CaO content and temperature, the maximum flow velocity of MgO slag increases from 0.043 to 1.34 mm/s. Under different initial CaO contents, the distribution trend of CaO volume fraction is basically the same, and the CaO volume fraction is evenly distributed between 50 and 225 mm in the furnace.Originality/valueThe influence of different contents of impurity calcium oxide on the process of electromelting magnesia was analyzed and a theoretical system was established.

Microstructure evolution, mechanical and abrasive wear properties of NiCrSiB-SiC composite coatings prepared on 16Mn low-carbon steel by Ni-based alloy catalyzed SiC decomposition

In this study, NiCrSiB-SiC composite coatings were prepared on 16Mn low-carbon steel by vacuum cladding technology using SiC and NiCrSiB mixed powders as raw materials for enhancing their wear resistance. The effects of different content of SiC particles on the microstructure evolution, mechanical and abrasive wear properties of the coatings were investigated. The results showed that SiC particles in all the NiCrSiB-SiC composite coatings with different SiC contents were completely decomposed into C and Si under the catalysis of Ni-based alloy. The out-diffused Si into the coating mainly led to the formation of the Ni3Si eutectic phase, while the out-diffused C introduced M7C3, M3C2, M2(C, B) and other hard phases. Besides, C also diffused to the substrate, leading to a carburizing effect, which remarkably enhanced the mechanical properties of the substrate. In the NiCrSiB-SiC composite coatings with high SiC content, the decomposition of SiC led to the remaining graphite phase. However, once the concentration of SiC was over high, excess graphite would deteriorate the compactness and adhesion of the coating, weakening its wear performance. The nanoindentation and abrasive wear experiments revealed that the composite coating with 5 wt% SiC particles had lower elastic modulus (E), higher hardness (H), H/E, and H3/E2, and its wear volume was only 1/10 of that of the substrate, indicating the best mechanical and wear properties. The excellent wear performance can be attributed to the combination of the in-situ formed carbides and borides hard reinforcing phases and the tough coating matrix composed of Fe and Si dissolved γ-Ni and Ni3Si eutectic phase.

Effects of B2O3-Bi2O3 addition on the dielectric properties of low-temperature-sintered MgO-TiO2(w) ceramics

The effects of different contents of B2O3-Bi2O3 on the sintering temperature and dielectric properties of MgO-12%TiO2(w) ceramics were investigated. B2O3-Bi2O3 addition effectively reduced the sintering temperature and improved the dielectric properties of ceramic samples; however, an excessive amount of B2O3-Bi2O3 led to the deterioration of dielectric properties. This is because Bi2O3 participated in the chemical reaction between MgO and TiO2 and generated a high-dielectric-loss Bi2Ti2O7 phase, resulting in an increased dielectric loss in the ceramic samples. In contrast, B2O3 formed a liquid phase to fill the grain gaps and pores during sintering, improving the densities of the ceramic samples. An appropriate amount of B2O3-Bi2O3 accelerated the reaction between MgO and TiO2 and formed ultralow-dielectric-loss phases—MgTiO3 and Mg2TiO4, and the dielectric losses of the ceramic samples decreased to an order of 10−5.

Enhanced Thermal Decomposition and Safety of Spherical CL-20@MOF-199 Composites via Micro-Nanostructured Self-Assembly Regulation.

The characteristics of high burning rate, high energy output, and low pressure exponent have always been the focus of development in the field of composite solid rocket propellants. In this paper, a metal-organic framework (MOF-199) compound is introduced to prepare micro-nanospherical CL-20@MOF-199 composites via the spray-drying self-assembly technique to reach the above goals. MOF-199, which acts as an attractive combustion catalyst and a safety regulator, is uniformly coated on the surface of CL-20 with close interface contact between particles, effectively accelerating the thermal decomposition of CL-20 and ensuring safety performance. The average noncovalent interaction (aNCI) analysis illustrates that there are strong C-H···O hydrogen bonds and van der Waals interaction between CL-20 and MOF-199 molecules, greatly enhancing the effect of interparticle assembly. The effects of different contents of MOF-199 on the thermal, safety, and energy properties of CL-20 were discussed. The thermal analysis demonstrates that MOF-199 has a significant thermal catalytic effect on CL-20, with an advanced peak temperature of thermal decomposition of 14.2 °C and a reduced activation energy barrier of 34.2 kJ·mol-1, mainly benefitting from more exposed catalytic active sites and close interface contact. In addition, CL-20@MOF-199 composites exhibit decreased mechanical sensitivity (IS: 21-40 cm, FS: 80-240 N) and excellent energy performance. This work clearly demonstrates that MOF-199 is both a superior combustion catalyst and a good safety buffer for CL-20, and it opens new potential for further applications of CL-20 in composite solid propellants.

Effects of different content of EGCG or caffeic acid addition on the structure, cooking, antioxidant characteristics and in vitro starch digestibility of extruded buckwheat noodles

The effects of different types and content of polyphenol addition on the structure, cooking, antioxidant characteristics and in vitro starch digestibility of extruded buckwheat noodles were investigated in this study. The result showed epigallocatechin-3-gallate (EGCG) was more easily combined with starch to form complex than caffeic acid, and amylose tended to be combined with polyphenols to form more complex. Amylose had a protective effect on polyphenols during extrusion process, which led to a significant increase of polyphenol content and antioxidant activity of extruded noodles. The addition of polyphenol and high amylose corn starch (HACS) improved the cooking quality of extruded buckwheat noodles. The extruded buckwheat noodles with 20 % HACS and 1 % EGCG had the lowest cooking loss of 6.08 %. The addition of EGCG and HACS increased the content of resistant starch and reduced predicted glycemic index (pGI). The noodles with 20 % HACS and 3 % EGCG had the lowest pGI (63.38) and the highest resistant starch (RS) content (61.60 %). This study provides a theoretical basis for the development of low pGI extruded buckwheat noodles.

Ladderlike Polyphenylsesquioxane‐Doped Cellulose Insulation Paper with Upgraded Mechanical Strength

Ladderlike polyphenylsesquioxane (L‐PPSQ) with special planar ladder structure is significant to upgrade the mechanical strength of cellulose insulation paper. In this study, the effect of different content of L‐PPSQ on mechanical properties and dielectric properties of cellulose is first investigated by molecular simulation, and then insulation paper doped with L‐PPSQ is prepared for experimental verification. It is indicated in the simulation results that the elastic modulus, bulk modulus, and shear modulus of the cellulose are enhanced up to 36.82%, 27.96%, and 41.80%, respectively, when L‐PPSQ is added at 3 wt%, and the cellulose model with 3 wt% L‐PPSQ possesses the lowest dielectric constant. The reason is that L‐PPSQ can enhance the hydrogen bonding network of cellulose, weaken the degree of molecular chain motion, and strengthen the strength of molecular chains, which in turn manifests as the enhancement of mechanical strength. It is shown in the experimental results that the tensile strength and elongation at break of the composite insulation paper can be enhanced by 16.7% and 35.09% when the L‐PPSQ content is 3 wt%, which is consistent with the simulation results. The short‐term aging test shows that L‐PPSQ can also upgrade the mechanical strength of the insulation paper at high temperatures.

Production and characterization of recycled low-density polyethylene/amazon palm fiber composites

The research aimed to evaluate the effects of different contents of jupati particles on the properties of composites with a matrix of recycled low-density polyethylene (LDPE). The composites were produced with 0%, 5%, 10% and 15% of jupati particles inserted in the LDPE matrix, and the moisture, bulk density, water absorption, flammability and mechanical resistance were determined. The inclusion of the lignocellulosic material caused an increase in the density, indicating absence of pores, and in the other properties of the composites, except the modulus of rupture. These results were related to its chemical characteristics and the low interaction with the matrix, which can be verified in the scanning electron microscopy images. The work results are interesting and propitiate the development of further questions related to the production parameters, different particle sizes and use of compatibilizing agents to verify the possible effects on the composites.

Effects of ATP on the Physicochemical Properties and Cytocompatibility of Calcium Sulfate/Calcium Citrate Composite Cement.

Adenosine triphosphate (ATP), acting as a source of energy, has effects on cellular activities, such as adhesion, proliferation, and differentiation. In this study, ATP-loaded calcium sulfate hemihydrate/calcium citrate tetrahydrate cement (ATP/CSH/CCT) was successfully prepared for the first time. The effect of different contents of ATP on the structure and physicochemical properties of ATP/CSH/CCT was also studied in detail. The results indicated that incorporating ATP into the cement did not significantly alter their structures. However, the addition ratio of ATP directly impacted the mechanical properties and in vitro degradation properties of the composite bone cement. The compressive strength of ATP/CSH/CCT gradually decreased with an increasing ATP content. The degradation rate of ATP/CSH/CCT did not significantly change at low concentrations of ATP, but it increased with a higher ATP content. The composite cement induced the deposition of a Ca-P layer in a phosphate buffer solution (PBS, pH = 7.4). Additionally, the release of ATP from the composite cement was controlled. The ATP was controlled releasing at the 0.5% and 1% ATP in cement by the diffusion of ATP and the degradation of the cement, whereas it was controlled by the diffusion process merely at the 0.1% ATP in cement. Furthermore, ATP/CSH/CCT demonstrated good cytoactivity with the addition of ATP and is expected to be used for the repair and regeneration of bone tissue.

Fabrication of gelatin methacryloyl/graphene oxide conductive hydrogel for bone repair

The ideal bone repair materials possess a series of properties, such as injectability, good mechanical properties and bone inducibility. In the present study, gelatin methacryloyl (GelMA) and graphene oxide (GO) were selected to prepare conductive hydrogel by changing the concentration of GelMA and GO during the cross-link process. The effects of different contents of GelMA and GO to the hydrogel performance were investigated. The results showed that the mechanical properties of the hydrogel kept 16.37 ± 1.89 KPa after adding 0.1% GO, while the conductivity was improved to 1.36 ± 0.09 μS/cm. The porosity of hydrogel before and after mineralization could reach more than 90%. The mechanical properties of mineralized hydrogel was improved significantly, could reach 26.38 ± 2.29 KPa. Cell experiments indicated that the mineralized hydrogel with electrical stimulation obviously improve the alkaline phosphatase activity of the cells. GelMA/GO conductive hydrogel could be a promising candidate for bone repair and bone tissue engineering.

Tailoring the strength and corrosion resistance of Al-7Si: Eutectic Si modification by Sr and Sc

The effects of different content of Sr and Sc on the microstructure, mechanical properties and corrosion resistance of an Al-7Si alloy were investigated. The presence of Sc in the Sr-modified Al-Si alloy resulted in multiple types of eutectic Si morphologies. The modification of eutectic Si improved the yield strengthen and elongation of Al-7Si alloys, but lead to the increase of boundaries between α-Al and eutectic Si particles, which caused decrease of corrosion resistance and polarization resistance. The incomplete modification offered a possibility to satisfy the require that a compromise between mechanical properties and corrosion resistance. The relationship between the content of Sr and Sc and the morphologies of eutectic Si in the alloy was also summarized.

Effect of Ti3C2Tx/Ag MXene fillers on the electrical conductivity of Ag-coated Cu conductive adhesives

In this paper, we prepared ECAs (electrical conductive adhesives) with high electrical conductivity by using Ag-coated copper powder and M − II (Ti3C2Tx/Ag powder) as conductive filler. M-Ⅰ (Ti3C2Tx) and M-Ⅱ were prepared by acid etching and hydrothermal methods, respectively, and the electrochemical properties of M-Ⅱ and the effects of different contents of M-Ⅱ on the conductivity of ECAs were investigated. M − II has a unique reticular structure which helps to create conductive pathways, and its high specific surface area provides a large number of active sites for charge storage, resulting in increased electrical conductivity. The experimental results show that the best conductivity is achieved when the M-Ⅱ powder content is 1.2%, with a volume resistivity of 4.84 × 10−6 Ω m, at which time the Ag-coated Cu powder content is 69.8%. It has been shown in many studies that only when Ag-coated copper powder content is 70%–80%, the resistivity reaches about 10−6 Ω m. This work showed that adding a small amount of M − II and reducing the amount of Ag-coated copper powder could maintain the high electrical conductivity of ECAs.

Effect of different contents of WO3 and B2O3 on the structure and thermal, mechanical, corrosion properties of phosphate glass

Effect of different contents of WO3 and B2O3 on the structure and thermal, mechanical, corrosion properties of phosphate glass