Resistant Materials Research Articles

Infestation and damage status assessment of white mango scale (Aulacaspis tubercularis) insect at boloso sore and boloso bombe districts of Wolaita Zone South Ethiopia

This fruit devastating pest of white mango scale (Aulacaspis tubercularis Newstead; Hempitera: Diaspididae) insect is an economically important pest and damages the mango fruit by sucking the sap through its piercing-sucking mouth part from mango leaves and fruits. Since the 2010 outbreak in Ethiopia due to a poor internal quarantine system this insect pest was distributed and invaded the whole mango-producing region in the country. Therefore, the aim of this study was to assess the infestation and severity status of WMS insects to get evidence for upcoming management investigations. The survey was carried out at Boloso Bombe and Boloso Sore districts in South Ethiopia Wolaita Zone in 2023. Among mango-producing farmers by using a semi-structural questionnaire 45 farmers were intervened through random selection. Geographic location and ten samples of mango leaf were collected from four cardinal directions per tree of each stop for examining the infestation and severity status of WMS. The occurrence of this pest at study locations was in 2016 as interviewed farmers respond. Since then, due to a lack of attention by farmers currently, it was distributed and covered the whole study area. As confirmed by this study the infestation ranged from 60 to 100% and damage or severity rated from moderate to very high. Among surveyed locations, 29% of mango farms were very highly, 52% highly and 20% moderately damaged. From the total study area, almost 31% of mango farms reduced 100% yield and the reduction of yield ranged from 50% to 100%. Before the outbreak of this invasive insect pest, the study area farmers were harvesting nearly 272 kg of mango fruit per tree and at normal times yield reduction was almost 43 kg per tree. After the prevalence of WMS insect per tree yield was almost 44 kg and the reduction of yield was alarmingly increased to 228 kg per tree as shown by this study data. Even though this insect pest is a devastating pest of mango fruit, however, it can be controlled through different management practices. Therefore, the management practice of this pest is categorized into three such as cultural, biological and biochemical. Culturally managed by Mango tree pruning, planting resistant materials, using proper spacing, cleaning or sanitation, burying infected residues and fruits, smoking different repellents of dry grass, animal dung, mango leaves and lemon bark or lemon mixed organic materials in one smoking can/pot and hanging inside mango tree. Foliar Spraying of various botanical extracts such as Neem seed extract (Azadirachta indica). Several concoctions made from ash, soap and goat urine were mixed and sprayed on infested mango fruit leaves and twigs. Various predators and parasitoids are used as Biological control. Soil drenching of systemic chemical insecticides also can control this insect pest. The way to control this serious damage and hinder the expansion of this invasive insect pest, integrated experimental investigation using the above-explained mechanisms will be advisable to enhance mango fruit yield. Int. J. Agril. Res. Innov. Tech. 14(2): 28-37, December 2024

Enhancing the detection efficiency of the 3D positive ion detector

Enhancing the 3D positive ion detector's efficiency is the objective of this study. The detector finds numerous applications in the fields of radiation biology, radiation dosimetry, radiation protection, radiation measurement etc. Generally, in 3D positive ion detector the cathode used is either high resistive glass or gold coated over ceramic glass. The detector efficiency has been reported as 2%max with high resistive glass cathode material and 9.2%max with gold coated ceramic glass. In the present study, we have significantly improved the detection efficiency by replacing these materials with an oxygen-free high conductivity (OFHC) copper cathode. This modification resulted in a substantial increase in the detector efficiency, reaching a maximum of 31.3%max. The study also presents a comparison between this enhanced performance and the previously reported efficiencies demonstrating the effectiveness of using high conductivity materials to improve ion detection capabilities.

Ultrasonic sprayed hollow ceramic/carbon microspheres function as thermal insulation, ablative resistance, and electromagnetic shielding materials

Ultrasonic sprayed hollow ceramic/carbon microspheres function as thermal insulation, ablative resistance, and electromagnetic shielding materials

Preparation and properties of acetylene-functional benzoxazines with comparative phenol sources

High heat-resistant polymer materials are required urgently as the fast development of the aerospace field. The cross-linking characteristic of polymers with the acetylene group provides us with an effective strategy. Here, a series of acetylene-functional benzoxazine monomers with different phenolic compounds, TERT-apa, BA-apa and THPE-apa, were synthesized, and their chemical structures were confirmed by Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) spectra. Their curing behaviors and polymerization reactions were analyzed by differential scanning calorimetry (DSC) and FTIR technology, and possible cross-linking structures were proposed. Meanwhile, their gelation reaction activation energies were obtained by the gelation time test. After curing at 200°C, the thermal properties of these cured polybenzoxazines were studied by Dynamic mechanical analysis (DMA) and Thermogravimetric analysis (TGA). Among them, the glass transition temperature (Tg) of p(BA-apa) can reach as high as 428°C, while p(THPE-apa) had a weight loss temperature over 400°C and a char yield of 60% at 800°C under N2. Therefore, this study shows that the introduction of the acetylene groups is a effective strategy for the preparation of high-performance polymers, which provides some promising high heat resistant materials for the aerospace field.

Effect of Different Tapered Gutta-Percha Points on Push-Out Bond Strength of Two Root Canal Sealers

Abstract Objective The purpose of this study was to compare the push-out bond strength of root canal filling with different tapered gutta-percha points of two root canal sealers. Materials and Methods One hundred and twenty mandibular premolar teeth were prepared with a Reciproc blue file to size R50 and divided into four groups (n = 30 per group), with group 1 receiving iRoot SP with 02-tapered gutta-percha point (iRoot02), group 2 receiving iRoot SP with match-tapered gutta-percha point (iRoot50), group 3 receiving canal sealer bioactive glass (CS-BG) with 02-tapered gutta-percha point (BG02), and group 4 receiving CS-BG with match-tapered gutta-percha point (BG50). All samples were stored at 37°C and 100% humidity for 1 week. The specimens were resected at 3.5 and 5 mm from the apex, and push-out bond strength was measured using a universal testing machine. Results iRoot02 had the highest push-out bond strength and differed significantly from iRootR50. BGR50 produced the lowest push-out values and showed no difference from BG02. Conclusions The amount of iRoot SP in the root canal filling influences the material's resistance to pushing out. It will be more resistant if the ratio of iRoot SP to gutta-percha is high. When gutta-percha points with different tapers were used, the amount of CS-BG had no effect on the push-out force.

Ballistic impact response of fibre metal laminates based on ramie fibre woven reinforced polyester

This research focused on evaluating the ballistic impact behavior of polyester-reinforced woven ramie fibers combined with aluminum fiber metal laminates (FMLs). The materials were structured in four specific configurations: two types of ramie composites (2-layer and 3-layer) and two FML configurations FML 2/2 and FML 2/3. Ballistic performance was assessed through both experimental and numerical testing under a controlled firing angle of 90 degrees with 9 mm projectiles. The findings clearly showed that the FMLs had superior energy absorption capabilities compared to pure ramie composites, with the FML 2/3 configuration standing out, absorbing 52.69 J of energy. This highlights the enhanced ballistic resilience of hybrid laminates, especially with increased composite layers. Therefore, the FML, particularly the FML 2/3, exhibits a significantly higher energy-absorbing capacity, making it more effective in reducing projectile performance post-penetration. The FML 2/3 configuration showed the greatest reduction in residual velocity in both experimental and simulation results, indicating superior effectiveness in absorbing ballistic energy compared to the other configurations. This finding suggests that adding layers to the composite, especially in the FML configuration, enhances the material's resistance to projectile penetration and effectively decreases the projectile's residual velocity. However, additional research is necessary to gain a comprehensive understanding of the high-velocity performance of thermoplastic fiber metal laminates (FMLs), particularly for their potential use in industrial applications.

Effect of Canna edulis starch addition on the properties of flour, rheology of dough and quality of semi-dry noodles.

Canna edulis is a high-quality resistant starch raw material, especially for making flour products. This study aimed to investigate the effect of Canna edulis starch (CES) on the properties of flour, rheology of dough and quality of semi-dry noodles. The CES replaced part of the wheat flour in the semi-dry noodle formula. One control formula containing wheat flour only, and five formulations based on wheat flour containing 8CES, 16CES, 24CES, 32CES and 40CES were prepared. The findings revealed that with the increase of CES, the peak viscosity and retrogradation value of the flour increased, and the melting enthalpy decreased. CES caused some bound water to migrate to a semi-bound water state, improving the rheological properties of the dough and enhancing the texture characteristics of the noodles. When the added amount of CES was 24%, the cooking loss rate was 1.687%, and the highest sensory score was 86 points. Simulation of starch in vitro digestion revealed that the hydrolysis rate of starch first increased and then decreased with the increase of CES addition, with the highest proportion of resistant starch content ranging from 44.27% to 79.66%. Compared with the control group, the expected glycemic index decreased after adding CES. These results assist in realization of comprehensive utilization of Canna edulis resources for the production of noodles with desirable qualities. © 2025 Society of Chemical Industry.

A Type of Low‐Temperature Resistant Material Based on Ethylene Propylene Monomer/Polypropylene Thermoplastic Vulcanizates Compatibilized by Polyisobutylene

A Type of Low‐Temperature Resistant Material Based on Ethylene Propylene Monomer/Polypropylene Thermoplastic Vulcanizates Compatibilized by Polyisobutylene

Effectiveness of Four Rootstocks against Fusarium wilt, Yield and Quality in Cucumber

Fusarium crown root rot caused by F. solani is one of the most important diseases that limiting cucumber cultivation all around the world. There is more than one way to deal with this disease, but sometimes these practises may be insufficient. For this reason, the use of resistant varieties and rootstocks gains importance in the control of soil-borne diseases. The objectives of this study are to determine the resistance of breeding materials to fusarium and to evaluate their rootstock performance and to reveal their effects on fruit yield and quality. To determine the Fusarium resistance level, 48 breeding materials were tested and four moderate resistant materials were grafted onto the hybrid Gordion variety. The effects of grafted plants on fruit yield and vegetative growth were evaluated. Early yield was also significantly higher in grafted plants than in the ungrafted control. Strongtosa had the highest fruit per plant, followed by RS 841 and 13×18 hybrid rootstock. Although higher yields were generally obtained in grafted plants compared to the control group. Additinally fruit length, fruit diameter, fruit shape index, fruit firmness and panel test were evaluated in grafted plants. These materials used as rootstocks increased plant growth and yield.

Experimental Study on Flexural Behaviour of Prefabricated Steel-Concrete Composite I-Beams Under Negative Bending Moment: Comparative Study.

The issues of numerous steel beam components and the tendency for deck cracking under negative bending moment zones have long been challenges faced by traditional composite I-beams with flat steel webs. This study introduces an optimized approach by modifying the structural design and material selection, specifically substituting flat steel webs with corrugated steel webs and using ultra-high-performance concrete for the deck in the negative bending moment zone. Three sets of model tests were conducted to compare and investigate the influence of deck material and web forms on the bending and crack resistance of steel-concrete composite I-beams under a negative bending moment zone. The findings indicate that, compared to a conventional steel-normal concrete composite I-beam, incorporating ultra-high performance concrete into the negative bending zone enhances the cracking load by 98%, resulting in finer and denser cracks, and improves the ultimate bearing capacity by approximately 10%. In comparison to the composite I-beam with flat steel webs, the longitudinal stiffness of the composite I-beam with corrugated steel webs is smaller, which can further enhance the bridge deck's resistance to cracking in the negative bending moment zone, and maximize the steel-strengthening effect of the lower flange of the steel I-beam. Based on the findings of this study, it is recommended to use steel ultra-high-performance concrete composite I-beams with corrugated steel webs due to their superior crack resistance, bending strength, and efficient material utilization.

An Experimental Study on Steel Fiber Effects in High-Strength Concrete Slabs

This study investigated the impact of varying steel fiber ratios by volume on the performance of HSC slabs. Incorporating steel fibers into high-strength concrete (HSC) has been shown to significantly enhance its mechanical properties, particularly by improving its load-bearing capacity. Furthermore, the addition of steel fiber reduces the reliance on traditional reinforcement bars, leading to a more efficient use of materials. This not only simplifies the construction process but also contributes to a reduction in overall construction costs. This study investigated the behavior of HSC slab specimens under loading and elevated temperatures. Three groups of specimens were created based on their thickness (8 cm, 12 cm, and 16 cm) using a single high-strength concrete mixture and four varying steel fiber proportions (0, 37.5, 75, and 150 kg/m³). Two-point monotonic loading was applied to each slab specimen until failure. To determine the splitting tensile strength, 12 cylinders were cast. Additionally, 84 cubes were cast to assess the effects of elevated temperatures and different cooling techniques on compressive strength (fcu). The results revealed that incorporating steel fibers into high-strength concrete slabs has a negligible effect on the concrete's density and compressive strength. However, it notably enhanced the splitting tensile strength and modulus of rupture. These improvements significantly boosted the material's resistance to cracking, making it more durable and better suited for applications requiring superior tensile performance. This is particularly important in structures subjected to dynamic or cyclic loading, where the risk of cracking and failure is greater. Doi: 10.28991/CEJ-2025-011-01-013 Full Text: PDF

Biomimetic PVA hydrogel and MMT reinforced TPU water-lubricated bearing materials for superior frictional properties and wear resistance

Biomimetic PVA hydrogel and MMT reinforced TPU water-lubricated bearing materials for superior frictional properties and wear resistance

Recent advances in different materials for moisture resistance of metal oxide-based gas sensors: A review

Recent advances in different materials for moisture resistance of metal oxide-based gas sensors: A review

Hollow conductive polypyrrole microtubes as microwave absorbents with good seawater corrosion resistance

Conductive polymers materials with hollow micro/nanostructure due to their special electrical properties and corrosion resistance have potential applications in microwave absorption, especially in marine environment. Herein, one-dimensional hollow conductive polypyrrole microtubes (H-PPyM) were prepared by in-situ polymerization of pyrrole monomer with methyl orange (MO) as soft template and FeCl3 as oxidant based on structural regulation strategy. The morphology and conductivity of H-PPyM can be easily controlled by adjusting the content proportion of MO. The results indicated that the surface morphology of polypyrrole changed from random granular to microtubular and the conductivity also gradually rose with the content increase of MO. When the content proportion of MO was 0.25 g, the obtained H-PPyM-0.25 composites possed notable microwave absorption capacity, simultaneously achieving ultrabroad effective absorption bandwidth (EAB, 6.7 GHz) and strong reflection loss value (RL, -33.6 dB) at a thickness of 2.6 mm with the filling content of only 10 wt.%, respectively. Furthermore, the corresponding H-PPyM-0.25 products soaked in corrosive medium (3.5 wt% NaCl solution) for one month still displayed stable tubular hollow structure and excellent microwave absorption performance with RLmin of -43.8 dB and EAB of 6.2 GHz. The research results can not only help to understand the relationship among the morphology and microwave absorption of PPy, but also open a new avenue for preparing excellent seawater corrosion resistant microwave absorption materials.

Dynamic damage characteristics and control mechanism of rocks anchored by constant resistance and energy absorption material

Dynamic damage characteristics and control mechanism of rocks anchored by constant resistance and energy absorption material

Effect of composite magnetic microspheres and curing time on the corrosion and wear properties of phosphate ceramic coatings

In order to enhance the corrosion and wear resistance of ceramic coatings in marine environment, different types of micro-nano structures were constructed on the surface of phosphate ceramic coatings by magnetic polystyrene (PS@Fe3O4) microspheres and curing time. Subsequently, the surface properties of the magnetic composite microspheres and coatings were characterized, and the corrosion and wear properties of the coatings were investigated. The results revealed that the microspheres were gradually decomposed with the increase of curing time, and the surface of the coating presented different micro-nano structure with convex, flat and concave. Compared to unstructured coating (NSC), the convex micro-nano structured coating (CXMNC) and concave micro-nano structured coating (CEMNC) possessed outstanding superhydrophobicity. Through three tests of the knife scraping, tape peeling and sandpaper abrasion, the coatings showed excellent bonding strength and mechanical durability. After a long immersion period (256h), the impedance modulus of CXMNC and CEMNC were 27 and 15 times that of NSC, respectively. Compared with the NSC, the wear rate of CXMNC and CEMNC was reduced by 31.09% and 5.42%, respectively. Compared with the uncorroded samples, the wear rate of NSC, CXMNC and CEMNC after the immersion corrosion (30 days) was increased by 127.23%, 59.18% and 65.48%, respectively. Therefore, the micro-nano structured coatings have superior corrosion resistance and wear resistance to NSC, and CXMNC so as to CEMNC, which will provide better insight into the development of new corrosion-wear resistant materials.

Preceramic polymer-hybridized phenolic aerogels and the derived ZrC/SiC/C ceramic aerogels with ultrafine nanocrystallines.

Phenolic and carbon aerogels have important applications for thermal insulation and ablative resistance materials in aerospace field. However, their antioxidant ability in long-term high-temperature aerobic environments faces serious challenges. To solve this problem, Zr/Si preceramic polymer hybridized phenolic resin (PR-ZS) aerogels were prepared via a facile sol-gel method. Compared with pure phenolic aerogel, the hybrid aerogels possess similar porous microstructure but larger specific surface area, better thermo-oxidative stability, and higher compressive strength. After carbonization at 1700 °C, the hybrid aerogels can be transformed to carbide ceramic aerogels with ultrafine nanocrystalline ZrC and SiC particles embedded in the carbon matrix. Ceramic aerogels exhibit good thermal insulative and anti-ablative properties in a butane torch simulated high-temperature and aerobic environment. The linear ablation rate is as low as 0.017 mm min-1, and the backside temperature is below 330 °C at a 20 mm in-depth position after 300 s of burning test, when the front temperature is approximately 960 °C. This work provides a facile approach to fabricate hybrid phenolic aerogels and derived ZrC/SiC/C ceramic aerogels, which target on applications for extreme environments in aerospace field.

High-temperature abrasive wear behaviour of strengthened iron-aluminide laser claddings

Strengthened iron-aluminides (Fe3Al-based) show notable mechanical properties alongside good scratch hardness up to 600 °C. To investigate the influence of strengthening mechanisms for alternative high temperature wear resistant materials, laser metal deposited alloys based on Fe with 30 at.% Al were studied in detail. After cladding the Fe30Al base material and its alloys – with either 5 at.% Si, 5 at.% C or 3 at.% Ti combined with 6 at.% B – thorough investigations by scanning electron microscopy, electron backscatter diffraction, nanoindentation, hot hardness measurements, and high temperature scratch tests were performed.All alloyed Fe3Al-based claddings show increased strength. The highest overall hardness of ~405 HV10 exhibits the carbon-alloyed one containing a high fraction of Fe3AlC0.6 carbides. Contrary, the Ti + B alloyed as well as the Si-alloyed claddings are superior with their scratch hardness (especially at elevated temperatures), through the formation of TiB2 precipitates and pronounced solid solution strengthening, respectively. Wear tests reveal decreasing wear rates with increasing test temperatures (from 20 to 500 to 700 °C) for all alloyed Fe3Al-based claddings due to the formation of abrasive-containing mechanically mixed layers. Contrary, the reference cladding, cobalt-based Stellite 21 exhibits not only a higher wear rate but also increased ones upon increasing the test temperature. Detailed investigations show that the scratch hardness correlates with the wear resistance and that the incorporation of abrasive material into the wear-induced formation of mechanically mixed layers is highly beneficial. Due to this self-protection effect, the promising overall high temperature behaviour, combined with the alloying concept (no Co, Ni, or Cr), these alloyed Fe3Al-based claddings are promising candidates for sustainable wear protection outperforming currently used wear protection solutions.

Measuring Work of Breathing in an Infant Model: Comparison of Static and Dynamic Test Methods

Abstract When an infant’s face becomes engaged with soft bedding materials, a suffocation hazard may be present that is associated with increased work of breathing (WOB). When resistive materials impede airflow, an infant must work harder to breathe and maintain homeostasis. Airway stressors within the infant sleep environment are felt to be risk factors for sudden unexpected infant death (SUID). To quantify the WOB, experiments were performed using a mechanical breathing model for dynamic measurements and compared with a static test method. The model was configured to measure the dynamic pressure and volume of the lungs as they changed during the breathing cycle. Pressure and volume data were used to calculate the WOB per cycle for a range of 12 restrictive bedding materials and 3 types of foam. In addition, static airflow resistance measurements were made using the same materials. It was found that there is a useful correlation between static airflow measurements and dynamic measurements of WOB. The measurement methods and apparatus are described herein.

Influence of energetic heavy ion sputtering on lifetime of alloy target

When energetic heavy ions are incident on negatively charged structure that collects and deposits ions, ion sputtering will occur. Metal wire is a structure commonly used for accelerating ions, the incidence of continuous high-throughput ions can cause surface loss of metal wire, affecting the service performance and lifespan of the metal wire. The SRIM software commonly used for calculating sputtering yield cannot consider the multi-body interaction problem contained in the alloy crystal structure. so, there is a significant error in calculating the sputtering yield of high-energy ions incident on alloy target. Based on the molecular dynamics method and Langevin temperature control model, the calculation model of ion sputtering parameters of energetic metal ions incident on alloy target is established in this work. The model is used to calculate the sputtering yield under the conditions of intact surface lattice of the target material and long-term incident surface lattice damage. The damages to the cathode metal wire under different incident ion fluences are further calculated, and the cross-sectional characterization of the metal wire is carried under typical working condition. The results show that the discrepancy between the experimental value and the theoretical value is less than 10%, which verifies the accuracy and applicability of the theoretical model. Based on this model, the search direction for sputtering resistant materials is proposed, meanwhile, a theoretical optimization is carried out to improve the service life of metal wire, and a method of using Ni-Ti alloy to improve the service life of metal wires is proposed, which is of great significance for predicting the service life of the metal wire under different conditions.