Increase In Strength Research Articles

Investigating the effect of polypropylene fibres and curing parameters on the workability and mechanical properties of concrete

Polypropylene fibers possess certain characteristics that make them an ideal counterpart to attain explicit advantages when used for building works, more specifically, when added to concrete. In this investigation, polypropylene fibers were added by weight of cement (0.25%, 0.5%, and 0.75%) in M20 grade of concrete and their impact on workability, compressive strength, and flexural strength were assessed and analyzed. The slump test revealed that as the polypropylene fiber loading in the concrete mix was increased, the workability of the mixture continued to decrease; the workability decreased by 11.11%, 19.44%, and 45.83% upon the addition of 0.25 %, 0.5%, and 0.75% fibers respectively in the concrete. The compressive strength, as well as the flexural strength of the concrete, increased monotonously with an increase in the curing time and fiber loading. For instance, in the case of acidic water curing, the compressive strength enhanced from 19.08 MPa to 22.85 MPa upon increasing the fiber content from 0.25% to 0.75%. Adding 0.25% polypropylene fiber resulted in an increase in the flexural strength of conventional concrete mix by 15.78% and 10.29% when cured in normal water for 28 days and 56 days, respectively. Both the compressive and flexural strength of the samples cured in normal water was found to be higher than the samples cured in acidic water and it was observed that the fibre-reinforced concretes were more resistant to acids than the normal unreinforced concrete.

Optimizing textile dyeing and finishing for improved energy efficiency and sustainability in fleece knitted fabrics

In the industrial range, optimizing dyeing and finishing energy is important to control environmental pollution. In the Dyeing stage to finishing of textiles gas, electricity, steam, and water are used 260 m3/hour, 591 kWh, 1.2 pounds/hour, and 8.69 tons/hour respectively. If textile professionals do not match the desired shade and quality of fabrics with the use of minimal resources the energy cost will be multiple times higher. This study investigates the change in the shade of fleece knitted fabrics from the dyeing unload to the finish stage and assumes a dyeing recipe adjustment, focusing on the impact of optimized dyeing and finishing processes. Also, it focuses on qualitative changes in properties across various color variations. Identical dyeing recipes for light, medium, and dark shades of red, blue, and navy. Properties such as GSM (grams per square meter), width, color strength, shade (darker/lighter, red/green, blue/yellow), shrinkage, spirality, pilling, bursting strength, and color fastness were analyzed. Dyeing to post-finishing, an increase in color strength (K/S) values was observed, with examples including minimum increases from 2.9 to 3.18 for light red and maximum from 19.3 to 22.9 for dark navy shade. Darker shades (DL*) were observed after stenter 1st pass (among all variants, red: 1.2 % to 8.1 %, blue: 4.5 % to 6.7 %, navy: 1.6 % to 2 %), while lighter shades (DL*) were observed following sueding and napping (among all variants, red: 3.1 % to 19.7 %, blue: 11.8 % to 19.7 %, navy: 14.8 % to 27.6 %). Greenish (Da*) and yellowish (Db*) tones are prominent across all colors in the finishing stages. Besides, other properties shrinkage, spirality, pilling, bursting strength, and color fastness significantly changed. These findings offer valuable guidance for dyeing professionals aiming to achieve the desired adjustment of shades that match the quality standard and produce sustainable fleece fabrics. To compensate for the shade lightening that occurs during the finishing process, it is recommended to keep the fabric shade slightly darker (5.70 % to 23.10 %) at the dyeing stage.

Physical and Mechanical Properties of Autoclaved Aerated Concrete (AAC) with Ceramic and Gypsum Waste (CGW) Addition Before and After Exposure to Direct Fire at Temperatures up to 920°C

This research endeavors to comprehensively explore the physical and mechanical properties of Autoclaved Aerated Concrete (AAC) with ceramic and gypsum waste (CGW) addition before and after exposure to direct fire at temperatures up to 920°C. The investigation focuses on determining the effects of CGW addition on AAC properties before and after exposure to direct fire at temperatures reaching 920℃ for 300 seconds. The main objective of this research was to determine the work density and compressive strength of AAC-CGW on the surface of direct fire exposure. In pursuit of this goal, various compositions of AAC with CGW, ranging from 5% to 30% wt/wt, were accurately prepared. The physical and mechanical were conducted before and after subjecting to direct fire testing. Important parameters such as work density, ranging from 593.71kg/m3 to 672.70kg/m3, and compressive strength from 1.64MPa to 2.39MPa, were analyzed. The findings demonstrated that the compressive strength exhibited an increase with CGW addition, particularly within the 5% wt/wt. The high point compressive strength value recorded was 2.39MPa for a 5% wt/wt CGW addition, reflecting a 45.73% increase in compressive strength compared to the reference sample (RS). The study also revealed convincing fire resistance results. Indicating for the reference sample (RS), the samples exhibited surfaces devoid of cracks, burns, or melting during direct fire exposure exceeding 920℃ for 300 seconds. Furthermore, CGW addition contributed to a remarkable 20.1% improvement in thermal insulation compared to the RS. Direct fire resistance testing had a positive influence on the physical and mechanical characteristics of AAC-CGW samples. The average work density experienced a 9.9% reduction, while compressive strength exhibited an 18.8% increase. Direct fire exposure led to an outstanding 53.30% enhancement in compressive strength compared to the sample.

Effect of prefatigue-induced persistent slip bands on the strength-ductility match in -oriented Cu single crystals

To explore the effect of persistent slip bands (PSBs) formed during cyclic loading on the static mechanical behavior of materials, [1‾12]-oriented Cu single crystals are selected as target materials, and the tensile behavior of Cu single crystals prefatigued to the stress saturation stage at different plastic shear strain amplitudes (γpl) and the corresponding microstructures, surface deformation features and fracture morphologies are systematically studied. The results show that the formation of few soft PSB ladder-like structures in hard dislocation veins during prefatigue deformation at γpl = 3.7 × 10−4 below the plateau region of cyclic stress-strain (CSS) curve can promote a synchronous improvement of strength and ductility (SISD) compared with the unfatigued crystal. As γpl increases to a lower value of 9.0 × 10−4 within the plateau region, the strength and ductility reduce sharply compared with the case at γpl = 3.7 × 10−4 due to more concentrated plastic deformation caused by a high volume fraction of prefatigue-induced PSBs. With continuously increasing γpl to a higher value of 2.3 × 10−3 within the plateau region, non-uniform dislocation distribution in labyrinth structures and the short spacing between labyrinth walls as well as the fine dislocation cells formed during tension jointly give rise to a slight increase in strength and ductility compared with the crystal prefatigued at γpl = 9.0 × 10−4. As γpl is increased to the level beyond the plateau region, the ductility and ultimate tensile strength continuously increase, resulting from the co-existence of wider deformation bands and dense dislocation walls.

Valorizing Biopolyester Suberin: Modification of Cellulose Nanocrystals and Performance Assessment in 3D-Printed Biobased Acrylates.

Suberin, a common biomass processing waste, is a complex biopolymer and a promising source for the biorefinery of chemicals. Six different approaches for the extraction of birch outer bark suberin fatty acids (SFAs) were explored, and their application in grafting the surface of cellulose nanocrystals (CNCs) was investigated. Successful CNC functionalization was controlled with FTIR and NMR analyses. In-depth research allowed us to evaluate the interface of the nanocellulose and polymer matrix. Three structurally distinct SFA-grafted CNCs were integrated into a vegetable oil-based acrylate resin in an ultralow concentration of 0.1 wt %. Five biobased acrylic resin formulations were prepared: without reinforcement, with CNC, and with three distinct SFA-grafted CNCs. Vat photopolymerization (VP) 3D printing was utilized for sample preparation. The effects of grafted CNC components on 3D-printed samples' thermal stability, thermomechanical properties, and wettability were evaluated in detail. CNC functionalization enhanced the interface with the polymer matrix, yielding up to a 2-fold increase in elongation and up to a 2.5-fold increase in strength in tensile and flexural tests compared to the polymeric matrix. The CNC-SFA-modified filler demonstrated performance comparable to, or even better than, petroleum-based chemical modification routes found in the existing literature. This study highlights a promising approach for green functionalization of CNCs and verifies its use in interface enhancement using a biobased acrylate matrix.

Grip strength predicts postoperative ileus among patients undergoing abdominal minimally invasive surgery: a prospective multicenter cohort study.

Postoperative ileus (POI) is a prevalent complication following abdominal surgery, leading to extended hospitalization and escalated medical expenses. Few studies have investigated the association between grip strength and POI after abdominal minimally invasive surgery (MIS). A prospective multicenter cohort study was conducted using data from a prospectively registered database of patients undergoing abdominal MIS from March to December 2022. Grip strength levels were categorized and analyzed for their association with POI using multiple regression analysis with demographic adjustments. A smooth curve was generated to visualize the linear relationship. Out of 501 eligible patients, 393 were analyzed, with 67 (17.05%) developing POI. Grip strength was significantly and independently associated with POI, with each 1kg and 8.57kg (SD) increase in grip strength resulting in ORs of 0.94 and 0.61, respectively. Grip strength categories specific to sex and age were significantly associated with POI incidence, with individuals in the high grip strength group having a lower risk. Subgroup analysis showed grip strength as a significant predictor of POI risk, especially for males and older individuals. Higher grip strength was associated with a significantly lower risk of POI in males (OR = 0.29, 95% CI 0.09-0.90, p = 0.031) and older adults over 60years old (OR = 0.31, 95% CI 0.10-0.98, p = 0.046). Grip strength can predict the occurrence of POI in patients undergoing abdominal MIS. This can help identify high-risk individuals and improve perioperative management for better outcomes.

High-Temperature Fatigue Degradation Behaviors of a 3D Braided C/SiC with a Thin Interlayer in Different Dry Oxygen Atmospheres

In order to evaluate the increase in the flexural strength of a 3D braided C/SiC composite comprised with a thin pyrolytic carbon (PyC) interlayer (TI C/SiC) under a load of 60 MPa with an amplitude of ±20 MPa at an oxygen partial pressure of 8000 Pa, the effect of temperature, oxidation and stress value on the length change in the sample, fracture behavior, residual flexural strength and fracture morphology were studied up to 1500 °C. It was found that the gauge length change behaviors of the material are related to (i) the positive damage of the thin interlayer and (ii) to the negative damage of the C phase. The most serious damage of TI C/SiC under 60 ± 20 MPa occurs in an oxygen partial pressure of 17,000 Pa at 1300 °C. When the oxygen partial pressure and/or the temperature are reduced, the positive C phase damage is relieved. In the case that the oxygen partial pressure, temperature and stress increase, the negative C phase damage is facilitated. The oxidation mechanism of the C phase is controlled by the inward diffusion of oxygen from the sample surface to the center; however, a higher stress is considered to change the oxygen diffusion mechanism by increasing the reaction of the C phase, with oxygen causing a widening of microcracks.

Performance evaluation of high-performance concrete mixes incorporating recycled steel scale waste as fine aggregates

In this study, steel-scale waste (SSW), a byproduct generated during the manufacturing of steel, was investigated as a potential alternative to natural fine aggregates (sand) for preparing high-performance concrete (HPC). Three grades of sand and SSW with different particle sizes were mixed in varying combinations. Three different compaction techniques (loose, tamped, vibration) were employed. The optimum packing density for both SSW and natural aggregates was achieved using the vibration compaction method. Since the combination of 50 % sand and 50 % SSW exhibited the best packing density for both materials, this bi-grade aggregate mixture was selected for the mix preparation. The mechanical tests (compressive strength, flexural strength) and durability assessment (bulk water sorptivity, rate of water absorption, chloride ion penetration) were performed to achieve the desired objectives. The specimens were exposed to two different curing regimes i.e., normal curing and heat curing at elevated temperature. A significant increase in compressive and flexural strength was observed with the increased content of SSW. A compressive strength as high as 140 MPa was obtained for the HPC mix containing SSW aggregates and steel fibers. The replacement ratio of SSW was optimized to achieve better strength and durability. Experimental results showed that heat curing was more effective than conventional curing methods in improving the performance of the concrete.

Efficient sealing of cemented sheath: An oil-responsive self-healing latex with toughness enhancement for cement composites

The integrity of the cemented sheath is important to the safe exploration of oil and gas resources. Sealing failure of cement sheath will result in formation fluid channeling and pressure carryover in the annulus. The both toughening and oil-responsive self-healing latex (TOS) was prepared to achieve efficient sealing of cemented sheath, and prolong its service life. The structure and oil swelling behavior of TOS, its toughening and self-healing effects on hardened cement paste (HCP) were analyzed by comprehensive characterizations. Results demonstrated that TOS possessed excellent stability and an oil swelling rate of 1235 %. Cement specimens by curing 28d containing 8 % TOS exhibited a 27.8 % increase in flexural strength, a 48.7 % reduction in elasticity modulus and a 33.8 % reduction in brittleness coefficient. The addition of TOS can effectively improve the toughness of cement. The average pore size of specimens containing 8 % TOS admixture decreased to 9.17 nm. This indicates that TOS enhanced the structural density of cement materials. The crack about 103μm in the cracking specimens with 8 % TOS was almost healed, and the corresponding permeability was reduced 99.1 % after curing in oil. Adsorption and film formation of TOS can resist the cracking of cement sheath, and the oil swelling expansion of film in cement matrix can repair the cracked structure.

Dampak Penggunaan Abu Marmer terhadap Kuat Geser Tanah Lempung

Soil is an important part of the building structure because it has a function as a support for the building. Therefore, soil stability must be considered so that building construction is safe and durable. There are types of clay soils that have high plasticity values and low shear strength. Soils like this require stabilization with the addition of additives such as marble ash. The purpose of this study was to determine whether the addition of marble ash content has an optimal impact on improving the plasticity, density, and shear strength properties. The added material used was marble ash with a content of 3%, 6%, 9%, and 12% by weight of dry soil. The specimens were differentiated based on their curing age before being tested by triaxial. Based on the research results, it was found that the use of marble ash had the maximum impact on improving the plasticity properties and maximum density at an addition of 6%. This was followed by a significant increase in shear strength at the same addition. A good curing age for increasing the angle of internal friction in the soil was obtained at 14 days.

Formation of a magnetized hybrid star with a purely toroidal field from phase-transition-induced collapse

ABSTRACT Strongly magnetized neutron stars are popular candidates for producing detectable electromagnetic and gravitational-wave signals. Gravitational collapses of neutron stars triggered by a phase transition from hadrons to deconfined quarks in the cores could also release a considerable amount of energy in the form of gravitational waves and neutrinos. Hence, the formation of a magnetized hybrid star from such a phase-transition-induced collapse is an interesting scenario for detecting all these signals. These detections may provide essential probes for the magnetic field and composition of such stars. Thus far, a dynamical study of the formation of a magnetized hybrid star from a phase-transition-induced collapse has yet to be realized. Here, we investigate the formation of a magnetized hybrid star with a purely toroidal field and its properties through dynamical simulations. We find that the maximum values of rest-mass density and magnetic field strength increase slightly and these two quantities are coupled in phase during the formation. We then demonstrate that all microscopic and macroscopic quantities of the resulting hybrid star vary drastically when the maximum magnetic field strength goes beyond a threshold of $\sim 5 \times 10^{17}$ G, but they are insensitive to the magnetic field below this threshold. Specifically, the magnetic deformation makes the rest-mass density drop significantly, suppressing the matter fraction in the mixed phase. These behaviours agree with those in the equilibrium models of previous studies. Therefore, this work provides a solid support for the magnetic effects on a hybrid star.

Capture behavior of self-propelled particles into a hexatic ordering obstacle

Abstract Computer simulations are utilized to investigate the dynamic behavior of self-propelled particles (SPPs) within a complex obstacle environment. The findings reveal that SPPs exhibit three distinct aggregation states within the obstacle, each contingent on specific conditions. A phase diagram outlining the aggregation states concerning self-propulsion conditions is presented. The results illustrate a transition of SPPs from a dispersion state to a transition state as persistence time increases within the obstacle. Conversely, as the driving strength increases, self-propelled particles shift towards a cluster state. A systematic exploration of the interplay between driving strength, persistence time, and matching degree on the dynamic behavior of self-propelled particles is conducted. Furthermore, an analysis is performed on the spatial distribution of SPPs along the y-axis, capture rate, maximum capture probability, and mean-square displacement. The insights gained from this research serve as valuable contributions to understanding the capture and collection of active particles.

Influences of short-term and long-term plasticity of memristive synapse on firing activity of neuronal network

Abstract Synaptic plasticity can greatly affect the firing behavior of neural networks, and it specifically refers to changes in the strength, morphology, and function of synaptic connections. In this paper, a novel memristor model, which can be configured as a volatile and nonvolatile memristor by adjusting its internal parameter, is proposed to mimic the short-term and long-term synaptic plasticity. Then, a bi-neuron network model, with the proposed memristor serving as a coupling synapse and the external electromagnetic radiation being emulated by the flux-controlled memristors, is established to elucidate the effects of short-term and long-term synaptic plasticity on firing activity of the neuron network. The resultant 7D neuron network has no equilibrium point and its hidden dynamical behavior is revealed by phase diagram, time series, bifurcation diagram, Lyapunov exponent spectrum and two-dimensional dynamic map. Our results show the short-term and long-term plasticity can induce different bifurcation scenarios when the coupling strength increases. In addition, memristor synaptic plasticity has a great influence on the distribution of firing patterns in the parameter space. More interestingly, when exploring the synchronous firing behavior of two neurons, the two neurons can gradually achieve phase synchronization as the coupling strength increases along the opposite directions under two different memory attributes. Finally, a microcontroller-based hardware system is implemented to verify the numerical simulation results.

Development of sustainable alkali activated composite incorporated with sugarcane bagasse ash and polyvinyl alcohol fibers.

The infrastructure boom has driven up cement demand to 30 billion tons annually. To address this and promote sustainable construction, researchers are developing solutions for carbon-neutral building practices, aiming to transform industrial waste into an eco-friendly alternative. This study aims to develop and enhance the mechanical and durability properties of alkali-activated composites (AACs) by incorporating varying amounts (5, 10, 15, and 20%) of finely ground bagasse ash (GBA) and polyvinyl alcohol (PVA) fibers. Results indicate that higher GBA content initially reduces the 7th and 14th-day strength but results in increased strength at later ages. The optimum 28-day strength is achieved with a 10% GBA content, leading to a 10% increase in compressive strength, 8% increase in tensile strength, and 12% increase in flexural strength. Additionally, the incorporation of GBA enhanced the resistance of the composite to chloride ingress, thus reducing its conductance and increasing the overall durability. This study demonstrated the potential of GBA as an eco-friendly material, emphasizing the significance of tailored AACs formulations for durable and sustainable construction practices.

Elevating mechanical and thermal performance on alkali‐treated pineapple/glass fibre sandwich composite

AbstractThe present work generated hybrid composite sandwiches by incorporating 65% epoxy resin and 35% reinforcements derived from pineapple and glass fibres. The specimens were subjected to mechanical characterization by tensile, flexural and impact examinations. Among the untreated samples, the specimens containing untreated pineapple fibres (PF) with a composition of 17% PF, 18% glass fibres (three layers) and 65% epoxy by weight (17PF/TLGF) showed the most superior mechanical characteristics. Nevertheless, specimens containing fibres treated with NaOH exhibited exceptional characteristics, attaining a tensile strength of 88.121 MPa, a flexural strength of 94.213 MPa and an impact energy of 4.1 J. These data indicate a 20% enhancement in both tensile and flexural strength as well as a 63% improvement in impact strength compared to specimens containing 35% PF and lacking glass fibres (35PF/0GF). In comparison to 17PF/TLGF, the specimens treated with NaOH exhibited a 4.34% gain in tensile strength, a 4.24% increase in flexural strength and a 9% increase in impact strength. Experimental TGA was performed on the chemically treated fibre composite specimens, specifically identified as 35PF/0GF and 17PF/TLGF. Approximately 260 °C marked the beginning of decomposition for the 35PF/0GF sample, but the 17PF/TLGF sample decomposed at roughly 310°C. In addition, the fragmented surface of the 17PF/TLGF sample was analysed using SEM. © 2024 Society of Chemical Industry.

Mechanical properties of reactive powder concrete under compression at ultra-low temperatures

In this paper, the mechanical properties of reactive powder concrete (RPC) at ultra-low temperatures were studied. RPC prisms (300 mm × 100 mm × 100 mm) were tested at ultra-low temperatures (20 °C, 0 °C, −20 °C, −40 °C, −80 °C, −120 °C, −165 °C) and resulting prism compressive strength, compressive stress-strain curve, and toughness were determined. The increase in prismatic compressive strength of RPC at ultra-low temperatures is greater than that of ordinary concrete, with an overall strength of about 2.12 times that of ordinary concrete. Pore water freezing behavior was also studied to assess the effects on the mechanical properties of RPC in ultra-low temperatures. The water-ice phase transition further improved the RPC strength. With the reduction in temperature, The change in elastic modulus of RPC change is small, the peak strain of specimens at different temperatures increases with the decrease in temperature. The peak strain of RPC showed an overall linear increase with decreasing temperatures, and the water-ice phase transition at negative temperature increases the peak strain of RPC, adding steel fibers improves the RPC ductility, limiting the fracture. With the temperature reduction, RPC toughness first increases and then decreases. The toughness is lowest at room temperature, and highest at −120 °C, which is 2.26 times higher than at room temperature. RPC has better toughness than normal concrete at different temperatures, the reduction of temperature relatively improves the toughness of RPC, and the addition of steel fibers plays a vital role in improving the toughness. This study can serve as technical support for using RPC to design liquefied natural gas full-capacity tanks.

Influence of diagonal reinforcement in grouted vertical joints between precast concrete wall panels, part I: Experimental investigation

AbstractMulti‐storeyed buildings are constructed using precast concrete large panels. Although the resistance to lateral loads during an earthquake can be provided by the walls, the vertical joints between the panels remain the weak links. Conventionally, a grouted vertical joint between precast panels is achieved using minimum number of overlapping transverse horizontal U‐bars or looped wire ropes from the adjacent panels, with a holder bar at the overlap, and subsequent grouting of the gap. It was observed that under in‐plane lateral loads, the shear behavior of such joints, especially those with looped wire ropes, is brittle. This paper presents a study to improve the behavior of conventional joints by introducing diagonal reinforcement (DR). Toward this, 13 specimens were tested under monotonic loading and 2 specimens were tested under quasi‐static cyclic loading. The parameters investigated were the types of transverse joint reinforcement, types and strengths of diagonal reinforcement. The compressive strengths of panel concrete and joint grout were kept similar to industry practice. The specimens with DR showed substantial increase of the shear strength and load retention beyond the peak. The presence of conventional transverse joint reinforcement in addition to DR, increases the retention capacity of the joint. Thus, the behavior of a joint with DR was found to be stronger and more ductile.

Significant Improvement in Magnetorheological Performance by Controlling Micron Interspaces with High Permeability Submicron Particles.

The shear yield strength, sedimentation stability and zero-field viscosity of magnetorheological fluids (MRFs) are crucial for practical vibration damping applications, yet achieving a balanced combination of these performances remains challenging. Developing MRFs with excellent comprehensive performance is key to advancing smart vibration damping technologies further. Theoretically, incorporating a multiscale particle system and leveraging synergistic effects between their can somewhat enhance MRFs' performance. However, this approach often faces issues such as insignificant increases in shear yield strength and excessive rise in zero-field viscosity. In response, this study employs a DC arc plasma method to synthesize a high magnetic permeability, low coercivity submicron FeNi particles, and further develops a novel CIPs-FeNi bidisperse MRFs. The introduction of submicron FeNi particles not only significantly enhances the shear2019 yield strength of MRFs under low magnetic fields but also promotes improvements in sedimentation stability and redispersibility without excessively increasing viscosity. Comprehensive performance analysis is conducted to explore the optimal content ratio, and detailed mechanisms for the enhancement of performance are elucidated through analysis of parameters such as chain-like structure, magnetic flux density and friction coefficient. Most importantly, the superior comprehensive performance combined with straightforward fabrication methods significantly enhances the engineering applicability of the CIPs-FeNi bidisperse MRFs.

Research on Pipeline Stress Detection Method Based on Double Magnetic Coupling Technology.

Oil and gas pipelines are subject to soil corrosion and medium pressure factors, resulting in stress concentration and pipe rupture and explosion. Non-destructive testing technology can identify the stress concentration and defect corrosion area of the pipeline to ensure the safety of pipeline transportation. In view of the problem that the traditional pipeline inspection cannot identify the stress signal at the defect, this paper proposes a detection method using strong and weak magnetic coupling technology. Based on the traditional J-A (Jiles-Atherton) model, the pinning coefficient is optimized and the stress demagnetization factor is added to establish the defect of the ferromagnetic material. The force-magnetic relationship optimization model is used to calculate the best detection magnetic field strength. The force-magnetic coupling simulation of Q235 steel material is carried out by ANSYS 2019 R1 software based on the improved J-A force-magnetic model. The results show that the effect of the stress on the pipe on the magnetic induction increases first and then decreases with the increase in the excitation magnetic field strength, and the magnetic signal has the maximum proportion of the stress signal during the excitation process; the magnetic induction at the pipe defect increases linearly with the increase in the stress trend. Through the strong and weak magnetic scanning detection of cracked pipeline materials, the correctness of the theoretical analysis and the validity of the engineering application of the strong and weak magnetic detection method are verified.

Investigating the combined influence of rolling, ECAP processes, and intermediate annealing on mechanical and microstructural properties of beryllium copper alloy 25

A beryllium copper alloy 25 underwent a series of processing steps involving rolling, equal-channel angular pressing (ECAP), and subsequent annealing. This study delved into the combined effects of these processes on the microstructural evolution and mechanical properties of the deformed beryllium copper alloy 25. The investigation utilized optical microscopy, scanning electron microscopy, transmission electron microscopy, room temperature Vickers hardness testing, and tensile testing. The findings reveal a notable enhancement in the strength of the beryllium copper alloy 25 while preserving its ductility after subjecting it to six ECAP passes followed by annealing at 210 °C for 20 min, applied to the rolled sample. Initially, an increase in number of ECAP passes resulted in a gradual reduction in grain size and a weakening of the alloy's texture. This led to an increase in ultimate tensile strength up to 333.5% without reducing in percentage elongation. Notably, after six ECAP passes, the average grain size decreased from 48 µm to less than 1 µm, yielding exceptional comprehensive mechanical properties with significantly improved strength and plasticity. The resultant material exhibits promising potential for fabrication into bars and plates for a wide range of applications in aerospace and marine industries.