Property Testing Research Articles

Mechanical properties of double-solid waste cement stabilized Macadam

Cement stabilized macadam base has high strength and excellent bearing capacity, but the problems of water-temperature sensitivity, easy shrinkage cracking and large demand for aggregate limit the further development and application of cement stabilized macadam base. At the same time, with the economy development, the increase of solid waste, such as waste tires and construction waste, has caused great pressure on the ecological environment. In order to ensure better mechanical properties and shrinkage resistance of the cement stabilized macadam on the basis of full use of solid waste. In this paper, mechanical properties tests such as unconfined compressive strength, splitting strength, compressive resilient modulus and shrinkage properties tests such as dry shrinkage and temperature shrinkage were conducted. Double-solid waste cement stabilized macadam mixture were prepared by partially replace fine and coarse aggregates with waste crumb rubber of different mesh and replacement ratios and recycled concrete aggregate of different replacement ratios, and their properties were investigated. The experimental results show that: (1) The good elasticity and toughness of waste crumb rubber can improve the crack resistance of cement stabilized macadam mixture. While the mechanical properties such as unconfined compressive strength and splitting strength will be reduced. (2) The mechanical properties of double-solid waste cement stabilized macadam mixture can be improved by partially replacing coarse aggregate with appropriate amount of recycled concrete aggregate with porous and rough surface, but it will adversely affect its shrinkage resistance. (3) The recommended particle size and replacement ratio of waste crumb rubber in double-solid waste cement stabilized macadam mixture are 40 mesh and 0.5%, respectively, and the recommended replacement ratio of recycled concrete aggregate is 75%. The mechanical properties indexes of double-solid waste cement stabilized macadam mixture can meet the specification requirements.

Total Momentum and Other Noether Charges for Particles Interacting in a Quantum Spacetime

There has been strong interest in the fate of relativistic symmetries in some quantum spacetimes, partly because of its possible relevance for high-precision experimental tests of relativistic properties. However, the main technical results obtained so far concern the description of suitably deformed relativistic symmetry transformation rules, whereas the properties of the associated Noether charges, which are crucial for the phenomenology, are still poorly understood. Here, we tackle this problem focusing on first-quantized particles described within a Hamiltonian framework and using as a toy model the so-called “spatial kappa-Minkowski noncommutative spacetime”, where all the relevant conceptual challenges are present but, as here shown, in technically manageable fashion. We derive the Noether charges, including the much-debated total momentum charges, and we reveal a strong link between the properties of these Noether charges and the structure of the laws of interaction among particles.

Inter-laboratory testing of thermal properties at ambient pressure on reference samples and core samples from the COSC-1 scientific drill hole, central Sweden

Summary We conducted comparative measurements of thermal properties of samples from nine cores of the ICDP COSC-1 borehole and four widely used rock references, using a steady-state and a transient divided-bar device, a transient plane source device, a modified Ångström device, as well as two optical thermal conductivity scanners. In addition, a caloric method provided benchmark values for specific heat capacity. A complementary thin-section analysis of the COSC-1 samples allowed us to calculate specific heat capacity according to Kopp’s law and thermal conductivity according to commonly used mixing models. Our results demonstrate agreement between the various test methods within ±10% for about one half of the investigated samples. Furthermore, almost all results for specific heat capacity agree with the predictions of Kopp’s law, though the significance of this correspondence is limited owing to large uncertainties in the experimental and theoretical values. The results for thermal conductivity fall within the most extreme theoretical bounds that account for anisotropy but for an amphibolite. Thermal anisotropy seems to contribute significantly to the deviations between results of the different transient methods that, however, cannot be reconciled by the available theoretical relations for apparent thermal conductivity of transversely isotropic materials. The combination of characteristic investigation volume of the individual methods and sample heterogeneity has to be considered responsible for variability of results, too, an issue whose clarification is calling for dedicated numerical modelling in the future, with the prospect to characterise thermal heterogeneity from observed differences.

Paper-Based Products as a Building Material for a Small Residential Unit: Testing of the Mechanical Properties

Paper-Based Products as a Building Material for a Small Residential Unit: Testing of the Mechanical Properties

Locality in collider tests of quantum mechanics with top quark pairs

Tests of quantum properties of fundamental particles in high energy colliders are starting to appear. Entanglement and Bell inequality violation in top and antitop quark system is of particular interest since top quarks are unstable particles that undergo a cascade decay. We argue for criteria for the spacelike separation between top and antitop quarks at their different decay stages. We considered causal separation at three different instances: at the top quark decay, at the W boson decay, and at the lepton/jet contact with the macroscopic apparatus. We showed that the spacelike fraction of events is the smallest, when requiring that both top quarks and W bosons decay within the spacelike interval. For high invariant masses, typically required for the Bell inequality violation, this is almost identical to just the top quark decay requirement. We also include an option for the angular correlation of the b quarks from top quark decay to be used for the spin correlation measurement. We require that both top quark and b hadron decays are spacelike separated. Again, we find that at high invariant masses it is almost identical to just the requirement of spacelike separation between top and antitop quarks. We provide numerical values for our proposed criteria. If such a criterion is satisfied, the system is guaranteed to not be in a causal connection. Published by the American Physical Society 2025

Estimating a firm-year measure of conditional conservatism for non-U.S. firms: evidence from Japan

ABSTRACT C_Score, a firm-year-level conditional conservatism measure, is widely used in international accounting research because of its parsimony, that is, the use of firm size, market-to-book ratio, and leverage as the main variables. However, it is developed for the U.S. and may not be valid in other countries because their institutional features differ from the U.S. We replicate the property tests of Khan and Watts (2009, ‘Estimation and empirical properties of a firm-year measure of conditional conservatism,’ Journal of Accounting and Economics 48: 132–150) and further investigate its validity using data from Japanese listed firms. Our findings are summarized as follows: first, market-to-book ratio and leverage are not statistically significant for many years. Second, C_Score does not predict future asymmetric timeliness of earnings. Third, the three variables’ contributions to C_Score’s variance fluctuate over time. Fourth, our result shows that firm size solely determines the measure for many years. Fifth, cash flow asymmetry, not accrual asymmetry, affects the asymmetric timeliness of earnings across the deciles based on C_Score. Finally, we find no relationship between C_Score and asset write-downs including non-current asset impairments. Overall, our findings suggest that C_Score is not valid for Japanese listed firms.

Innovative porous panels made from alpine tree bark-fibre bundles for enhanced acoustic and thermal insulation

ABSTRACT To tackle climate change, raw material shortages and global competition, new technologies should better utilize existing resources. Tree bark, an abundant by-product from Alpine sawmills, offers a promising opportunity despite its heterogeneous nature. In this study, tree bark was homogenised into fibrous material and subsequently processed into novel binder free low-density and therefore porous fibreboards. The aim was to develop effective panels for acoustic and thermal insulation by varying the key parameters bark species, fibre size, density and its variations. The findings highlight the effectiveness of bark fibre-based panelss as thermal and acoustical insulators, achieving densities of 170–330 kg/m³, a noise-reduction coefficient (NRC) exceeding 0.5 for most specimenss, and thermal conductivity below 0.08 W/(m·K). Significant variations in fibre length, density, and tree species indicate the need for tailored manufacturing adjustments. Testing involved impedance tube methods for sound absorption and dynamic plane source tests for thermal properties. This study provides initial validation of this approach, underscoring its potential for future research in utilising tree bark effectively.

Structure–Properties Correlations in Novel Copoly(urethane-imide) Films Selectively Destructed Under Thermolysis and Hydrolysis in Alkaline Media

The paper describes changes in the structure, morphology, mechanical and thermal properties of porous film samples of poly(4,4′-oxidiphenylene)pyromellitimide prepared as a result of selective destruction of urethane blocks in copolymers composed of pyromellitimide blocks and polyurethane blocks. The initial samples of the new composition of statistical copoly(urethane-imide)s (CoPUIs) were prepared via polycondensation methods using pyromellitic dianhydride (PMDA), 4,4′-oxidyaniline (ODA), 2,4-toluylenediisocyanate (TDI), as well as polycaprolactone (PCL) and poly(1,6-hexanediol/neopentylglycol-alt-adipic acid) (ALT) as monomers. The molar ratio of imide and polyurethane blocks in CoPUI was 10:1. The initial films were heated up to 170 °C to complete the polycondensation processes, after which they were subjected to thermolysis and hydrolysis. The thermolysis (thermal degradation) of copolymers was carried out by heating the initial samples to temperatures of 300 °C or 350 °C. Then, the thermolized films were subjected to chemical degradation in hydrolytic baths containing an aqueous solution of potassium hydroxide. As a result, urethane blocks were destroyed and removed from the polymer. The resulting products practically did not contain polyurethane links and, in chemical composition, were practically identical to poly(4,4′-oxidiphenylene)pyromellitimide. NMR and IR spectroscopy, atomic force microscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry and dynamic mechanical analysis and mechanical properties testing were used to determine the differences in the structure and properties of the initial copolymers and targeted products. The effect of the conditions of destructive processes on the structure, morphology and mechanical properties of the obtained porous polyimide films was determined. From a practical point of view, the final porous films are promising as membranes for filtering aggressive amide solvents at high temperatures.

Mechanical Properties Test and Microscopic Mechanism of Lignin Combined with EICP to Improve Silty Clay

To enhance the improvement effect of Enzyme-Induced Carbonate Precipitation (EICP) technology more effectively, an abundant renewable resource—lignin—was introduced as an additive during the EICP modification process of silty clay. The mechanical properties of the improved soil specimens were analyzed from a macroscopic point of view by using unconsolidated undrained (UU) triaxial tests and unconfined compressive strength (UCS) tests to determine the optimal lignin content and curing time. The micro-mechanism of the improved soil specimens was elucidated from the microscopic point of view by combining scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests. The experimental results showed that lignin synergized with EICP could effectively improve the mechanical properties of the soil, and the mechanical properties of the co-consolidated soil specimens were better than those of the single consolidated and untreated soil specimens as a whole. The single EICP-consolidated soil specimen had undergone brittle damage; lignin could enhance the toughness of the soil and weaken its brittle characteristics. With the increase of lignin content, the mechanical indicators of co-consolidated soil specimens showed the trend of increasing and then decreasing, and reached the optimum at 0.75%. Moreover, the addition of lignin significantly increased the cohesive force, while the friction angle was less affected. With extended curing time, the mechanical indicators of the co-consolidated soil specimens increased overall, and tended to stabilize after 7 days of curing, hence selecting 7 days as the optimal curing time. From the microscopic point of view, lignin provides nucleation sites for the calcium carbonate precipitates generated by EICP, and the joint action of the two can fill the soil pores and cement the soil particles, thereby improving the overall strength of the soil. The results of the study can provide a theoretical basis and practical reference for the construction of foundation projects in silty clay areas.

Translation and psychometric evaluation of the Thai version of TeamSTEPPS® teamwork attitudes and teamwork perceptions questionnaires

ABSTRACT Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS®) is a strategy for improving communication and team climate in hospitals. While it shows promise, it remains an untested tool among health care professional teams. A cross-sectional design with survey methodology was implemented. We scrutinized the psychometric properties of the TeamSTEPPS Teamwork Attitudes Questionnaire (T-TAQ) and Teamwork Perceptions Questionnaire (T-TPQ) among 301 health care professionals in Thailand. This study follows an instrument testing design guided by two phases: I) Translation phase and II) Psychometric properties testing. A content validity index (CVI), confirmatory factor analysis (CFA), and McDonald’s omega were conducted. The study presents confirmatory factor analyses and descriptive data. Both the T-TAQ and T-TPQ are self-administered questionnaires consisting of 27 and 32 items, respectively, utilizing a five-point Likert scale to assess five key components: Team structure, Leadership, Situation monitoring, Mutual support, and Communication. Psychometric evaluations indicated good internal consistency and validity for these instruments among Thai health care professionals, with McDonald’s omega values ranging from 0.68 to 0.89 for T-TAQ and 0.85 to 0.95 for T-TPQ. Confirmatory factor analysis supported the construct validity of both the Thai T-TAQ and T-TPQ. The T-TAQ and T-TPQ prove to be reliable and valid instruments. The scale can be effectively utilized as a tool for assessing Thai health professionals’ teamwork attitudes and perceptions.

Microstructural Characteristics and Mechanical Properties of Welded Joints and Base Material of Ultra-Supercritical Pipelines Before and After Service

This study investigated the microstructural evolution and mechanical property degradation of ultra-supercritical welded joints and base material (HR3C steel) before and after service. Mechanical property tests, including tensile and impact property tests, were conducted. The results show that the tensile strength, yield strength, elongation, and impact properties of the welded joints and base material after service were lower than those of unserviced specimens. Furthermore, optical microscopy, scanning electron microscopy, and transmission electron microscopy were used to observe the welded joint and base material specimens before and after service. In the initial state, the welded joints and base material had an austenitic microstructure and a diffusely distributed strengthening phase with the composition NbCrN. Moreover, high-temperature exposure led to precipitation processes. After service, Cr-rich M23C6 carbides with a chain-like structure precipitated near the grain boundaries of the welded joints and base material, leading to the aggregation of voids at the grain boundaries. This indicates that the coarsened M23C6 carbides at the grain boundaries negatively affect grain boundary strength, which is the main factor causing the reduction in steel plasticity and toughness. In addition, NbCrN mainly precipitated inside the grains, accompanied by dislocation pinning. The inhibitory effect of the dispersed particles on the dislocations allows the steel to maintain strength properties comparable to the initial state after service. However, the gradual deposition of NbCrN eventually degraded the strength properties.

Effect of friction stir processing on wire arc additively manufactured ER70S-6/SS308L bimetallic FGM

In this research, wire arc additive manufacturing (WAAM) is employed to fabricate a bimetallic steels component using ER70S-6 and SS308L. However, this process involves high power densities and significant heat inputs, which elevate the risk of unfavorable grain structures and defects. To mitigate this issue, friction stir processing (FSP) is applied, utilizing a unique tool featuring a flat shoulder without a pin. The resulting samples undergo testing for mechanical and metallurgical properties. The microstructure of ER70S-6 reveals ferrite with small amounts of pearlite at the grain boundaries. The upper portion of the deposited sample exhibits more pronounced grain refinement compared to the lower section, largely due to the rapid cooling rate and thermal cycling effects during layer deposition. This grain refinement is attributed to dynamic recrystallization, which enhances the hardness of the FSP-treated sample relative to its initial as-deposited state. Tensile tests indicate a significant increase in tensile strength, accompanied by a reduction in percentage elongation after FSP. The fatigue crack growth rate is higher along the longitudinal direction of bi-metallic joint as compare to transverse to the joint.

Effect of friction stir welding parameters on the microstructure and mechanical properties of AA7075/YSZ composite joints

This study presented the friction stir welding (FSW) of AA7075/YSZ composite. The process was conducted by employing several rotational speeds (ω) (800 rpm, 1000 rpm, and 1200 rpm) and traverse speeds (v) (25 mm/min, 50 mm/min, and 75 mm/min). Various parameters were then primarily analysed on this AMC, including weldability, microstructure, mechanical behaviour, and fractography. The microstructure of the welded joints was examined using an optical microscope (OM) and a field emission scanning electron microscope (FESEM). This study then assessed the correlation between the welding parameters and mechanical properties using three test types: (i) tensile test, (ii) three-point bending test, and (iii) Vickers microhardness measurement. A tool constructed using high-speed steel with a cylindrical pin profile was also utilised. Consequently, the defect-free sound welds were observed with equiaxed grains at the nugget zone (NZ). The mechanical property test also indicated a high efficiency level in the joints. Notably, the maximum tensile and bending strength were achieved when ω and v were 1000 rpm and 25 mm/min, respectively. The NZ also demonstrated higher microhardness than other zones, in which the highest microhardness of 300 Hv was achieved when ω and v were 1200 rpm and 75 mm/min, respectively.

The Mechanisms of Nano‐AlN Content in the Microstructure and Mechanical Properties of Fe–25Mn–9Al–8Ni–1C–0.2Ti Alloy

In order to design a high‐strength, tough alloy for structural components, Fe–25Mn–9Al–8Ni–1C–0.2Ti–xAlN (x = 0, 0.25, 0.5, 0.75, and 1 wt%) alloys are prepared by powder metallurgy combined with vacuum arc melting. It can be seen from microstructure that the AlN/Al preform obtained by homogenizing mixing followed by vacuum pressureless sintering is added to the arc melting in the form of raw materials, and the AlN phase can exist stably and be uniformly distributed in the matrix. The main phases of the alloys are composed of austenite, ferrite, and TiC. With the increase of AlN content, the ferrite content is decreased and the grains are refined. The distribution of ferrite grains is changed from network to needle‐like and dot‐like morphology. Mechanical property test results reveal that the addition of the nano‐AlN can maintain the stability of the tensile strength while significantly improving its elongation after fracture. Specifically, when the AlN content is 0.5 wt%, the elongation after fracture reaches the maximum value of ≈55.8%, representing ≈98.5% improvement compared to the matrix alloy. It is attributed to the promotion of slip line formation by nano‐AlN, resulting in a higher density of slip lines within the alloy.

Study on the Hydrogen Evolution Reaction of Reinforced Concrete during Electrochemical Repair under the Influence of BIEM.

Based on the bidirectional electromigration (BIEM) technique, a corrosion inhibitor solution was prepared by mixing 1 mol/L triethylene tetramine with deionized water. The effects of current density, charging time, and corrosion inhibitor on critical current density and hydrogen content of rebar were investigated. Subsequently, the hydrogen embrittlement risk of rebar was further characterized by mechanical property tests. Finally, the bearing capacity and crack distribution characteristics of the components during electrochemical repair were revealed based on the microstructure of the steel fracture. Studies have shown that the corrosion inhibitor in the BIEM electrolyte reduces the polarization potential, increases the critical current density, and finally inhibits the hydrogen evolution rate. The hydrogen evolution reaction increases with the increase of current density and energizing time. The critical hydrogen evolution current density of concrete specimens measured ranges from 0.796 to 0.833 A/m2. In addition, the current density range of 1-7 A/m2 has no effect on the yield strength, yield platform, and ultimate strength of steel. With the increase of 1 μg/g hydrogen content, the fracture energy ratio of steel bars decreases by 12.18%, and the sensitivity coefficient of hydrogen brittleness increases by 9.92%.

Optimization of Plasma Welding Sequence and Performance Verification for a Fork Shaft: A Comparison of Same-Direction and Reverse-Direction Welding.

The shift fork shaft is a key component in transmissions, connecting the shift fork in order to adjust the gear engagement. This study investigates the effects of different welding sequences on deformation and residual stress during plasma welding of the shift fork shaft. A temperature-displacement coupled finite element method, using ABAQUS simulation software and a double ellipsoid heat source model, was employed for the numerical analysis. The simulation results show that welding in the same and opposite directions leads to opposite deformation directions but similar deformation magnitudes. However, opposite-direction welding generates more significant stress concentration. After determining an optimal welding process, experimental welding was conducted. Microstructural observations of the weld seam and critical areas, along with mechanical property tests, revealed that the welds were well formed with no surface defects. The heat-affected zone (HAZ) exhibited a mixture of martensitic and non-martensitic phases, while the fusion zone (FZ) underwent phase transformation and recrystallization, forming fine-grained ferrite with martensite. Microhardness (HRC) in the weld seam ranged from 35 to 50, with the FZ and HAZ hardness higher than that of the base material (BM). The second weld pass showed significantly higher hardness in the FZ than the first pass. The tensile strength of the weld joint reached 94% of the base material strength, though plasticity and toughness were reduced. Fracture surface analysis indicated a combination of brittle cleavage and localized plastic deformation.

Supercritical CO2-Stable Cementing Materials Based on Vinyl Ester Resin for Maintaining Wellbore Integrity.

Ensuring long-term wellbore integrity is critical for carbon dioxide geological storage. Ordinary Portland cement (PC) is usually used for wellbore primary cementing and plug operation, and set cement is easily corroded by acidic fluids, such as carbon dioxide, in underground high-temperature and high-pressure (HTHP) environments, resulting in a decrease in the mechanical properties and an increase in permeability. In order to achieve long-term wellbore integrity in a CO2-rich environment This study introduces materials such as thermosetting vinyl ester resin (TSR), filler composite resin (FCR), and low-cost resin cement (RC). Corrosion experiments were conducted using four materials in 28 days under supercritical carbon dioxide gas and water phase conditions of 60 °C and 10 MPa. The samples were characterized through mechanical property testing machines, core permeability measuring instruments, FTIR, XRD, and SEM. The results proved that after corrosion, PC mechanical properties decreased, the permeability increased, and the microscopic composition and morphology changed greatly. Penetrating corrosion occurs in the sample in the gas phase environment, and propulsive corrosion from outside to inside occurs in the water phase environment. However, TSR, FCR, and RC materials all maintain excellent resistance to carbon dioxide corrosion in gas and water environments. They have higher compressive strength and extremely low permeability compared to ordinary Portland cement. These three materials' compressive strengths can be maintained around 131, 99, and 58 MPa, and permeability can be stabilized at <6 × 10-7, <6 × 10-7, and 0.16 mD levels. In summary, the above three materials all show better performance than ordinary Portland cement and are promising alternative materials that can be used in primary cementing and plug operations of carbon dioxide geological storage wells.

Reasons for good high-temperature tensile rupture property of high-W content (Nb,W) co-alloying TiAl-based alloy under low stress

In order to explore why the high-W content TiAl-based alloy under low stress has better tensile rupture property, we still choose the vacuum-consumable-melted Ti-44Al-4Nb-1W-0.1B alloy. We carried out tensile rupture property testing at different time periods and different temperatures. The W content in (α2+γ) lamella matrix and microstructure before and after tensile rupture property testing are studied. At 800 °C, the B2 phase content gradually decreases and the W content in (α2+γ) lamella matrix gradually increases with the extension of time periods. For example, at 800 °C for 1370h, the B2 phase content has decreased from initial 12.024% to 1.188%. And, W content in matrix has increased from initial 0.88at.% to 1.07at.%. The tensile stress accelerates the radial diffusion of W atom. Importantly, EBSD analysis shows that, under low stress, there is no obvious stress concentration in the B2 phase region (≤800 °C), which avoids premature fracture, and makes B2 phase playing a good role in coordinating stress and strain, thus improving the tensile rupture property. However, at 900 °C, there is a slight stress concentration in the microstructure, leading to the formation of many holes, which is harmful to the tensile rupture property.

Corrigendum to “Size effect of typical hygrothermal properties test values for building insulation materials” [Energy Build. 325 (2024) 115049

Corrigendum to “Size effect of typical hygrothermal properties test values for building insulation materials” [Energy Build. 325 (2024) 115049

Kinetics analysis of radical photopolymerizations for UV-curable nanocomposites based on cellulose nanocrystals: Promoting and enhancing mechanisms.

The interfacial interactions between the enhanced nanoscale components and the polymer matrix, as well as the photopolymerization behavior of the composite system, are of paramount importance to the quality and performance of photo-curable nanocomposites. Cellulose nanocrystals (CNCs), a novel class of green reinforcing materials, are anticipated to facilitate the development of high-performance applications of advanced functional materials. Herein, the promoting and enhancing effects of modified CNCs on photo-curable nanocomposites are studied. As confirmed by the FTIR spectra, the active radicals introduced on the surface of the modified CNCs promote a stronger interfacial chemical interaction between the CNCs and the photopolymer molecules. Infrared thermography is performed to reflect the thermal energy changes during the photocuring of nanocomposites for investigating the acting mechanism of the modified CNCs on the curing behavior. Notably, the nanoscale structure and enhancement effect of CNCs contribute to the effective promotion of the curing reaction of the polymer matrix molecules, and increase their crosslink density. The non-isothermal differential scanning calorimetry (DSC) test is employed to assess the thermal properties of photocured nanocomposites with varying contents of modified CNCs, in order to identify the optimal UV curing process. Kinetic analysis based on the Kissinger model indicates that CNCs not only facilitated the formation of polymer networks, but also played a role in optimizing the reaction paths and reducing the energy barriers of the reactions. The results demonstrated that the 0.75 wt% CNC nanocomposites exhibited the most favorable reactivity at 50 and 100 mW/cm2 UV intensities, which is consistent with the mechanical property test data. In terms of micro-mechanism, the active radicals on the surface enhance the ability of CNCs to chemically bind to the photopolymer. This is coupled with their significant interfacial effects, which facilitate the formation of strong interfacial binding. The aforementioned findings provide a solid foundation for the construction of high-performance photo-curable nanocomposites.