Test Material Research Articles

Simplifying perovskite solar cell fabrication for materials testing: how to use unetched substrates with the aid of a three-dimensionally printed cell holder.

This work demonstrates that unetched substrates can be reliably used in perovskite solar cell (PSC) fabrication. Chemical etching and laser patterning of the bottom electrodes are time- and resource-consuming processes. In particular, when testing novel conductive substrate materials, such as metallic or bio-based substrates, etching or patterning could be entirely unfeasible or could require significant process optimization. Avoiding these steps could accelerate research on PSCs, yet the literature shows no attempts to override these steps. Here, PSCs were fabricated and characterized using three-dimensionally printed holders with spring-loaded pins. We show that devices made on unetched substrates have, on average, a similar performance to those made on etched substrates (16 ± 1% and 16.0 ± 0.7%, respectively). Our study provides a new strategy for fabricating PSCs, particularly when etching and laser patterning are impractical.

Strategies for reusing multiple recycled powders: Evaluating the mechanical performance and sustainability of Engineered Cementitious Composites (ECC)

Engineering Cementitious Composites (ECC) are fibre-reinforced cementitious materials with excellent tensile strain capacity. Recycling powder from building and demolition waste can improve the ecological efficiency of concrete and reduce the cost of raw materials. In this study, recycled glass powder (RGP) was used to partially replace traditional cement. Based on using a 1:1 replacement of recycled brick powder (RBP) and recycled concrete powder (RCP) for fine aggregates, two sets of variables were set: the RGP substitution rate (10 %, 15 %, 20 %, and 25 %) and RGP particle-size range (38–75 μm, 75–150 μm, and 150–300 μm). Comprehensive material testing and mechanical experiments were conducted, including X-ray diffraction analysis, thermogravimetric analysis, shrinkage tests, uniaxial compressive tests, uniaxial tensile tests, and scanning electron microscopy. The results indicated that fully substituting quartz sand with RBP and RCP enhanced the ECC performance. Incorporating RGP significantly improved the ultimate tensile strain and crack-propagation ability of the ECC while reducing the 90-d shrinkage rate. The 28-d compressive strength and tensile strength have some loss, but can meet the strength requirements. SEM showed that incorporating RGP weakened the bonding strength of the fibre matrix, making it easier for the fibres to be pulled out. By evaluating the experimental results, the mix ratio of a 20 % substitution rate and 75–150-μm size was selected. A material-sustainability indicator (MSI) analysis of the raw materials and production process of RGP-ECC was performed. The embodied energy, carbon emissions, and economic indices were reduced to a certain extent, thereby improving the ecological efficiency of concrete.

Ultramicroporous zinc-aminotriazole MOF with customized alkaline pore environments for highly efficient capture of CO2 from flue gas

CO2 capture from natural gas and N2-rich flue gas is essential for improving the utilization of natural resource gases reducing CO2 emission, thereby alleviating the greenhouse effect. However, achieving effective Adsorptive separation of CO2 from CH4, N2, and O2 based on molecular sieving is still challenging and rarely reported, but selectively capturing CO2 places high desires on maximizing separation efficiency. Here, we report a zinc-aminotriazole ultramicroporous metal–organic framework (ZnATZoxH2O), constructed from zinc carbonate, 3-amino-1,2,4-triazole (ATZ), and oxalic acid with water as the only solvent. ZnATZoxH2O features NH2-functionalized and pore channels around 3.6 Å, which preferentially adsorb CO2. This material exhibits high CO2 uptake of 61.9 cm3 g−1 at 298 K and 1 bar and significantly high IAST selectivity for CO2/N2 (>103) and CO2/CH4 (>105) and CO2/O2 (>104). Theoretical GCMC simulations reveal that negatively charged amino groups decorated on the pore channel surface and carboxylic acid in the pore environment enhance the binding affinity over CO2 through electrostatic interactions for preferential capture of CO2. Single-component adsorption experiments and dynamic breakthrough experiments mutually validated the superior separation performance of this material and dynamic column breakthrough tests to produce high dynamic CO2 separation productivity of 2.017 mmol g−1 and 3.4 mmol g−1 for CO2/N2 (15/85), CO2/CH4 (50/50), and 2.26mmol g−1 CO2/N2/O2 (15/80/5). Non-hazardous water as a synthetic solvent to assemble highly stable and efficient CO2-selective materials makes it promising for practical industrial applications.

Development of wall volley digital test in badminton

Abstract: Introduction. Badminton is a sport that is popular with all levels of society, because it is easy to play and does not require a large field, and can even be played indoors or outdoors. Therefore, the game of badminton in Indonesia can develop rapidly. One of the tests in badminton definitely uses the wall volleyball test to determine the skill level of training children or students. As is known, the wall volleyball test is a very good test to see how far a person’s hitting ability in badminton is. The form of solving existing problems is by conducting research and developing wall volleyball tests so that teachers and coaches, especially athletes, no longer have doubts about their badminton skills. Objective. To develop one of the skills test tools in badminton, namely wall volleyball. Method. This research uses the research and development method which is used to produce certain product designs, test the effectiveness and validity of the designs that have been created so that the product is tested and can be used by the public. Results. Questionnaire results from small-scale tests on the development of digital-based wall volleyball tests in PB. Persada Kulon Progo Yogyakarta, showed an assessment percentage of 95.38% and was categorized as “Decent”. With such results, it is very feasible to continue this development to large-scale testing to see how feasible the results are with more people trying it and from different places. Large-scale trials were carried out at the PB club. PWS Godean Sleman and PB. Arjuna Bantul with a total of 35 athletes who met the criteria. Questionnaire results from a large-scale test of the development of a digital-based wall volleyball test in PB. PWS Godean Sleman and PB. Arjuna Bantul showed an assessment percentage of 99.56% and was categorized as “Decent”. With such results, this development is very feasible to continue to the next stage, namely effectiveness. Testing the validity of this digital-based wall volleyball test instrument includes testing material with a score of 11 out of 13 maximum scores and getting a percentage of 84.61% (Decent). Practitioner testing with a score of 11 out of 13 maximum scores and obtained a percentage of 84.61% (Layal). Meanwhile, testing the validity of test equipment experts with a score of 30 out of 32 maximum scores received a percentage of 93.75% (Decent). Based on the results of the data percentage above, what has been developed by the researchers received the title “feasible” and was declared valid. The first trial test between digital and manual tests was not significant because the results obtained were the same. Meanwhile, for the 2 digital and manual experimental tests, t = 4.779 and sig = 0.000 Sig < α (0.000 < 0.05), thus meaning that the 2 digital experimental tests are significantly different from the 2 manual tests. Conclusion. The development of a digital-based wall volleyball test was stated to be significant in achieving better results than the manual one.

Impact of deposition pressure on the structural, nanomechanical, and tribological properties of δ-TaN coatings deposited via magnetron sputtering on Ti6Al7Nb alloy

In the present study, δ-TaN thin films were deposited by reactive magnetron sputtering (physical vapour deposition) on Ti6Al7Nb alloy by varying the deposition pressure (0.8–0.2 Pa). Their crystalline structure, chemical composition, surface roughness, and surface morphology were investigated by using grazing incidence X-ray diffraction, energy dispersive spectroscopy, scanning probe microscope, and field emission scanning electron microscopy (FESEM), respectively. Structural analysis results confirmed the deposition of cubic δ-TaN thin films along the (111) basal plane; moreover, spherical dome-like surface morphology was observed by FESEM. Further, to analyze the nanomechanical properties of the deposited δ-TaN coatings, such as hardness (H) and modulus (E), scratch tests were performed utilizing the nanomechanical system. Moreover, friction and wear properties of the coating and bare sample (substrate) were investigated on nano-tribometer equipment using a rotary ball-on-disk type configuration. The stainless steel (SS-316) and silicon nitride (Si3N4) balls were used as the counter materials for the tribological tests. The observations of nanomechanical tests revealed that H (GPa), E (GPa), and H/E ratio values increased from 11.83 to 28.30 GPa, 176.02 to 248.45 GPa, and 0.06 to 0.11, respectively, with the decrease of the deposition pressure. In the scratch test, the highest critical load (cohesion failure) was found for δ-TaN coating deposited at the lowest deposition pressure (0.2 Pa). Tribological results of δ-TaN coatings demonstrated average coefficient of friction (COF) value ranges between 0.066–0.092 and 0.072–0.029 against steel and Si3N4 balls, respectively. The wear rate values were observed to vary from 8.15 × 10−5 to 7.56 × 10−6 and from 1.77 × 10−3 to 8.99 × 10−6 against steel and Si3N4 balls, respectively. Generally, the average COF and wear rate decreased against 316 SS and Si3N4 balls as the deposition pressure of coatings decreased. However, the coating deposited at 0.8 and 0.6 Pa against Si3N4 ball showed early delamination of the coating, resulting in the sudden fluctuation in COF plots and higher wear rate in the range of 10−3 mm3/N.m.

An interplay between cross-cultural and psychometric factors in the Montreal Cognitive Assessment: Experience from the language of a small nation

The present study aimed to test the hypothesis that the total word length on the Memory subtest of the Czech version of the MoCA, which is 12 syllables compared to the English version of 7 syllables, would have a significant effect on Delayed Recall scores compared to the newly created well-balanced version of the test (further MoCA-WLE). In the original Czech version of MoCA, we replaced the 12-syllable word list in the Memory subtest with a 7-syllable list (MoCA-WLE) to make it equivalent to the standard English version in this respect. We analyzed data from 83 participants in the original MoCA group (70.63 ± 7.01 years old, 14.61 ± 3.17 years of education, 30.12% males) and 83 participants in the MoCA-WLE group (70.72 ± 6.95 years old, 14.93 ± 3.48 years of education, 30.12% males). We did not find evidence for a significant word-length effect in the original MoCA versus MoCA-WLE Delayed Recall in either the Mann–Whitney U test (W = 3418.0, p = .932) or multilevel binomial regression (b = 0.10, 95% posterior probability interval [−0.46, 0.68]). The present study shows cross-cultural limits in the adaptation of the test material. The results underline the caveats of such an approach to test adaptation. Fortunately, 12-syllables in the MoCA Memory Czech version versus the original 7-syllable list did not show a detectable word-length effect. We did not find evidence for differential item functioning or cultural item bias. The original MoCA Czech version is psychometrically comparable to the original English version.

One-Port Coaxial Line Sample Holder Characterisation Method of Dielectric Spectra.

A technique for solving the one-port closed coaxial transmission line sample holder scattering equation for complex permittivity inversion for lossy materials is presented. A non-linear least-squares procedure is used for the determination of parameters for the specification of the spectral functional form of the complex permittivity. The method allows for accurate retrieval of many low- and high-permittivity dielectric materials in the frequency range of 1 GHz to 3 GHz inserted into the coaxial cell. Using this method, the complex permittivity of a number of liquids and a Maltese soil known as Bajjad soil have been extracted by measurements using a short terminated coaxial transmission line sample holder. The proposed novel inversion method is mainly based on the reflection coefficient of the test material. The measured results of the complex permittivity of liquid dielectrics such as ethanol, methanol, and TX100 are validated and compared with previously published data obtained from measurements made by the National Physical Laboratory (NPL) using a two-port measurement setup made with the same commercial coaxial transmission line sample holder used in the one-port setup. Since the technique allows broadband measurements, it has been used to characterise the soil dielectric spectrum in the frequency range of 1-3 GHz, which is also compared with results from a two-port setup of the same coaxial line. The experimental results are a validation of the proposed approach for different types of materials.

Deep Indentation Tests of Soft Materials Using Mobile and Stationary Devices.

Measurements of the properties of soft materials are important from the point of view of medical diagnostics of soft tissues as well as testing the quality of food products and many technical materials. One of the frequently used techniques for testing such materials, attractive due to its non-invasive nature, is the indentation technique, which does not puncture the material. The difficulty of testing soft materials, which affects the objectivity of the results, is related to the problems of stable positioning of the studied material in relation to the indentation apparatus, especially with a device held by the operator. This work concerns the comparison of test results using an indentation apparatus mounted on mobile and stationary handles. The tested materials are cylindrical samples of polyurethane foams with three different stiffnesses and the same samples with a 0.5 or 1 mm thick silicone layer. The study presented uses an apparatus with a flat cylindrical indenter, with a surface area of 1 cm2, pressed to a depth of 10 mm (so-called deep tests). Based on the recorded force changes over time, five descriptors of the indentation test were determined and compared for both types of handles. The tests performed showed that the elastic properties of foam materials alone and with a silicone layer can be effectively characterized by the maximum forces during recessing and retraction and the slopes of the recessing and retraction curves. In the case of two-layer materials, these descriptors reflect both the characteristics of the foams and the silicone layer. The results show that the above property of the deep indentation method distinguishes it from the shallow indentation method. The repeatability of the tests performed in the mobile and stationary holders were determined to be comparable.

Study of the fuel irradiation capsule using NEPTUNE_CFD software

The Fuel Irradiation Capsule (FUICA) is an experimental device designed to irradiate fuel elements in a Material Testing Reactor (MTR) during long period. This component is being studied for implementation in the Jules Horowitz reactor (RJH) under construction in France (1).Its function is to irradiate and to cool fuel sample on a passive way by transferring the thermal energy generated to the device periphery, through an annular zone of confined and pressure-regulated water (2). Its external wall, kept cold by the reactor cooling circuit, allows for the heat extraction. Natural convection is the driving force for the heat transfer between the fuel element and the cold wall of the device. By eliminating any internal forced convection cooling system, the device becomes relatively simple and cost-effective.This paper describes the device modeling carried out using the NEPTUNE_CFD software (3). The present work, in its first part, focuses on the behavior of the device depending on the heat flux, and in its second part, the sensitivity to boundary conditions. The objective is to provide a way to design and optimize the fuel capsule thermal characteristics. For that, an arbitrary size of fuel capsule is chosen in order to analyze the physics involved. A sensitivity study is then presented in order to highlight the influence of the physical parameters on the fuel capsule performance.Three operating ranges for the heat transfer are exhibited in this study: moderate in the liquid phase, the heat transfer becomes optimal in the two-phase regime, and even improves with the level of heat flux before deteriorating abruptly for high flux called Critical Heat Flux (CHF). Two observations also arise to improve thermal transfer: in the liquid phase, it is necessary to reduce the water thickness to improve convection, and in the two-phase regime, the heat transfer increases proportionally to the heat flux. In the end, the irradiation capsule is capable of extracting very high heat flux.

Analysis of the Suitability of Ultrasonic Testing for Verification of Nonuniform Welded Joints of Austenitic-Ferritic Sheets.

The purpose of the presented research was to determine the suitability of using ultrasonic testing (UT) to inspect heterogeneous, from a material point of view, welded joints on the example of the joints of a ferritic steel element with elements made of an austenitic steel. The echo technique with transverse (SEK) and longitudinal wave heads (SEL) addressed this issue. Due to the widespread use of 13CrMo4-5 and X2CrNiMo17-12-2 steel grades in the energy industry, they were selected as the test materials for the study. The objects of the presented research were welded joint specimens with thicknesses of 8, 12, and 16 mm and dimensions of 300 × 300 mm, made using the 135 metal active gas (MAG) process with the use of the Lincoln 309LSi wire-a ferritic-austenitic filler material. The stages of the research task were (1) making distance-amplitude curve (DAC) patterns from the test materials; (2) preparation of specimens of welded joints with artificial discontinuities in the form of through-holes; (3) performing UT tests on welded joints with artificial discontinuities using heads with 60° and 70° angles for the transverse wave and angle heads for longitudinal waves with similar beam insertion angles; (4) selection, by radiographic testing (RT), of welded joint specimens with natural discontinuities in the form of a lack of sidewall fusion; (5) performing UT tests on welded joints with natural discontinuities, using heads as welded joints with artificial discontinuities. It was found that (1) the highest sensitivity of discontinuity detection was obtained by performing tests on the ferritic steel side, which is due to the lower attenuation of the ultrasonic wave propagating in ferritic steel compared to austenitic steel; (2) the best detection of discontinuities could be obtained using a longitudinal ultrasonic wave; (3) there is a relationship between the thickness of the welded elements, the angle of the ultrasonic beam introduction, and the effectiveness of discontinuity detection.

Development of Independent Curriculum IPAS Teaching Materials Using a Project-Based Learning Approach Assisted with the Kvisoft Flipbook Maker Application to Increase the Learning Motivation of Class IV Primary School Students

This research aims to develop IPAS teaching materials using a Project Learning approach assisted by the Kvisoft Flipbook Maker application to increase the learning motivation of fourth-grade elementary school students. This type of research is Research and Development (R&D) research using a 4-D development model consisting of four stages: analysis, design, development, and implementation. The media developed is science and technology teaching materials using a Project Learning approach assisted by the Kvisoft Flipbook Maker application to increase the learning motivation of fourth-grade elementary school students. The results of the research show that: the validity test of IPAS teaching materials obtained an overall validity value of 91.80 % in the very valid category; The teacher's practicality results were 93.30 % in the convenient category and the students' practicality results obtained a percentage of 93.50 % in the convenient category; the effectiveness used in increasing the learning motivation of fourth-grade elementary school students received an N-gain value of 0.73 in the high category. From the results of this research, it can be concluded that the IPAS teaching materials using the Project Based Learning approach assisted by the Kvisoft Flipbook Maker application to increase the learning motivation of fourth-grade elementary school students are valid, practical and effective and can increase the learning motivation of fourth-grade elementary school students.

Effects of Carbon Fiber Content on the Crystallization and Rheological Properties of Carbon Fiber-Reinforced Polyamide 6.

Carbon fiber (CF)-reinforced polyamide 6 (PA6) composites have an excellent performance, attributed to properties such as light quality, high strength, and vibration reduction, and they are widely used in fields such as aerospace and transportation. Four kinds of carbon fiber-reinforced polyamide 6 (CF/PA6) composite pellets with carbon fiber contents of 20, 30, 40, and 50 wt.% were prepared using twin screw extrusion. The results were characterized using a simultaneous thermal analyzer, capillary rheometer, electronic universal material testing machine, and scanning electron microscope (SEM); their crystallization, rheological behavior, mechanical properties, surface structure, etc., were studied. DSC results indicate that an increase in carbon fiber content enhances the thermal stability of CF/PA6 and narrows the crystallization window but has a minor effect on the molecular chain diffusion time. The crystallinity reaches its maximum at a carbon fiber content of 40 wt.%, reaching 55.16%. The steady-state rheological behavior reveals that CF/PA6 behaves as a pseudoplastic fluid, exhibiting shear-thinning behavior. When the carbon fiber content is 40 wt.%, the power law exponent (n) reaches its maximum, and the consistency coefficient (K) decreases by 300 Pa⋅sn compared to the 30 wt.% content. With increasing temperature, n increases while K decreases. SEM observations reveal that samples with carbon fiber contents of 20 wt.% and 40 wt.% exhibit better fiber dispersion and orientation. However, the interfacial bonding strength is superior in the 40 wt.% sample. When the carbon fiber content reaches 50 wt.%, significant injection molding defects occur at the clamping end, leading to extensive matrix tearing during tension testing.

Remineralizing effect of NSF on artificial enamel caries

IntroductionNanotechnology offers new approaches and endless opportunities for remineralizing tooth decay without being toxic or causing allergies. This study aimed to determine the effect of nanosilver fluoride (NSF) on the remineralization potential of enamel caries-like lesions compared to 5% sodium fluoride varnish in permanent teeth.MethodsFifteen teeth (molars and premolars) were gathered, cleaned, and polished using a scaler. After sectioning the teeth mesiodistally and removing the roots, the thirty specimens were subjected to a demineralized solution to induce early enamel lesions and then assigned randomly into two equal groups. The test materials were applied, and then all the specimens were subjected to a pH cycling model for 30 days. DIAGNOdent and surface roughness were investigated, and an evaluation of the enamel Ca and P weight% for Ca/P ratio calculation was done using SEM-EDX to analyze the specimens at the end of the study. The data were analyzed using an independent t-test.ResultsThe mean values for the DIAGNOdent measurements for NSF and NaF at baseline and after demineralization were not significantly different (p > 0.05). After treatment, NaF varnish showed a significantly higher mean DIAGNOdent measurement (11.8 ± 5.80) than NSF (4.7 ± 1.6). The mean surface roughness of the NaF group (1.64 ± 0.39) was much higher than NSF’s mean surface roughness (1.07 ± 0.21). Specimens treated with NSF had statistically significant smoother surfaces (p < 0.001). The NSF group had a higher mean Ca/P ratio (2.9 ± 0.35) than NaF (2.2 ± 0.11). This difference was statistically significant (p = 0.012).ConclusionThe study reveals that nano silver fluoride is a more effective treatment than sodium fluoride varnish in enhancing teeth’s clinical characteristics, particularly in terms of mineral content and surface roughness, suggesting it could be an improved strategy to prevent dental caries and maintain enamel integrity.

The effects of setup parameters on the measured kinetic output of cervical disc prostheses

Mechanical testing machines are used to evaluate kinematics, kinetics, wear, and efficacy of spinal implants. The simulation of "physiological" spinal loading conditions necessitates the simultaneous use of multiple actuators. The challenge in achieving a desired loading profile lies in achieving close synchronization of these actuators. Errors in load application can be attributed to both the control system and the intrinsic sample response. Moreover, the presence of friction in the setup can have an impact on the measured outcome. The optimization of setup parameters can substantially improve the ability to simulate spinal loading conditions and obtain reliable data on implant performance. In this study, a reproducible kinematic test protocol was developed to evaluate the sensitivity of the kinetic response (i.e., measured loads, moments, and stiffnesses) of a cervical disc prosthesis to several testing parameters. In this context, five ceramic ball and socket sample implants were mounted in a 6 DOF material testing machine and tested with a constant axial compressive force of 100 N in two motion modes: 1) flexion-extension (±7.5°) and 2) lateral bending (±6°). Parameters including rotation rate, slider friction, friction between the samples' articulating surfaces, and moment arm were considered to determine their effects on measured kinetic parameters. The sensitivity analysis indicated that all setup parameters except friction between the samples' articulating surfaces had a substantial effect on the results. The findings were then compared to predictions from a free body diagram to determine the optimal setup parameters. Consequently, the setup with the lowest rotation rate and employing passive sliders yielded results that were consistent with the free body diagram. This study demonstrated the significance of a comprehensive setup evaluation for reliable and reproducible testing of spinal implants, also for comparison between labs.

Mutagenicity and DNA damage assessment of locally produced nano-hydroxyapatite-silica-glass ionomer cement on human periodontal ligament fibroblasts using Ames and Comet assays

AimThis research assessed the mutagenicity and DNA damage of a novel type of nano-hydroxyapatite-silica glass ionomer cement (nano-HA-SiO2-GIC) and a conventional GIC (cGIC) using Ames and Comet assays. MethodsCell viability was tested on human periodontal ligament fibroblasts (HPLFs) using 3.125 mg/ml, 6.25, 12.5, 25, 50, 100 and 200 mg/ml, on both types of GICs employing MTT assay. For the Comet assay, HPLFs were treated with IC50, IC25 and IC10 of test materials and the tail moments were measured. In the Ames test, four genotypic variants of strains of Salmonella typhimurium (TA100, TA98, TA1537 and TA1535) and a strain of Escherichia coli (WP2 uvrA) were employed. The material tested was extracted using sterile distilled water (0.2 g per ml) at 37 °C for 72 h. This was considered as 100 %, which was diluted to 50, 25, 12.5 and 6.25 % utilizing sterile distilled water. These five concentrations were incubated with the bacterial strains with and without metabolic activation (S9), along with appropriate positive controls. The number of revertant colonies was used to evaluate the outcome. ResultsThe highest cell viability (159.4 %) for nano-HA-SiO2-GIC was noticed at 3.125 mg/ml, while the lowest (24.26 %) was observed at 200 mg per ml. IC50, IC25 and IC10 values were 95.27, 51.4 and 20.1 mg/ml for cGIC, 106.9, 55.8 and 22.9 mg/ml for nano-HA-SiO2-GIC, respectively. The IC10 of both test materials showed no significant DNA damage compared to that of the negative control based on the Comet assay. The plate treated with nano-HA-SiO2-GIC showed less than double the average number of revertant colonies compared to that of negative control with regard to the Ames test. ConclusionsIt can be concluded that nano-HA-SiO2-GIC is non-mutagenic based on the Ames test and did not cause DNA damage at the lowest concentration of IC10 based on the Comet assay.

The Process of Steam Oxidation Degradation of High Cr Steel after 125 000 Hours at 568 °C under 16.5 MPa

AbstractThe aim of this work was to analyze the effect of steam oxidation when TP347HFG grade steel was exposed to industrial conditions for 125 000 hrs at 568 °C under 16.5 MPa pressure. The testing material was acquired from one of the coal power plants operating in Poland. Comprehensive investigations were carried out on the outer surface and cross section of the exposed sample using XRD, SEM/EDS and TEM. The analysis revealed the development of a fine grain oxide scale thickness spanning from 20 to 200 µm, consisting Fe2NiO4 (78 %), Cr1.3Fe0.7O3, Fe2O3 (0.8 %) and Fe3Co (0.8 %). Cross-sectional observations showed the formation of grains rich in Nb precipitates type MX carbonitrides surrounded by M23C6 carbides developed as a continuous net at the grain boundaries. The extent of material degradation under the influence of temperature, pressure and exposure time has been meticulously discussed. Graphical Abstract

Promoted electrochemical performance by MOF on MOF composite catalyst of microbial fuel cell: CuCo-MOF@ZIF-8 and the comparison between two-step hydrothermal method and dual-solution method

The microbial fuel cell (MFC) is a device that simultaneously achieves electricity generation and sewage degradation. In this study, a novel cathode catalyst metal-organic frameworks (MOFs) have been fabricated by two-step hydrothermal and dual-solution method (CuCo-MOF@ZIF-8). The synthesized trimetal MOFs exhibited a 3D badminton-like structure morphology and porosity. The results of the characterizations showed that CuCo-MOF@ZIF-8 possesses greater surface area porosity and novel functional groups. The Trimetal MOF-on-MOF mode not only demonstrated the stability of the structure but also enhanced its mechanism. Molecular mechanism analysis revealed changes in the organic ligand and metal binding site due to the transformation of Cu2+ to Cu+, Co2+ to Co3+, and Zn–N to Zn–O organic connection. Furthermore, differences between the two fabrication methods were compared. The solid-state single preparation (CuCo-MOF@ZIF-8-1), was synthesized using the two-step hydrothermal method; the liquid mixed preparation material (CuCo-MOF@ZIF-8-2), was synthesized using the dual-solution method; they exhibited completely different chemical structures and morphologies during material testing and characterization. The maximum output power density of CuCo-MOF@ZIF-8-2-MFC was 246.38 mW/m2, about 2.49 times of ZIF-8 (98.72 mW/m2). The output voltage of CuCo-MOF@ZIF-8-1-MFC was measured at 357 mV over 10 d, while that of CuCo-MOF@ZIF-8-2-MFC reached 365 mV over 12 d.

Crop Safety and Weed Control of Foliar Application of Penoxsulam in Foxtail Millet.

Grass damage has become an important factor restricting foxtail millet production; chemical weeding can help resolve this issue. However, special herbicides in foxtail millet fields are lacking. Penoxsulam has a broad weed control spectrum and a good control effect. In this project, Jingu 21 was used as the test material, and five different concentrations of penoxsulam were used for spraying test in the three-five leaf stage. In this experiment, the effects on the growth of foxtail millet were discussed by measuring the agronomic characters and antioxidant capacity of foxtail millet after spraying penoxsulam. The results showed that: (1) penoxsulam is particularly effective in controlling Amaranthus retroflexus L. (A. retroflexus) and Echinochloa crus-galli (L.) Beauv. (E. crus-galli), but is ineffective in controlling Chenopodium album L. (C. album) and Digitaria sanguinalis (L.) Scop. (D. sanguinalis); (2) the stem diameter, fresh weight, and dry weight of the above-ground parts decreased with the increase in spraying amount; (3) as the spraying dosage increased, the superoxide (SOD), peroxidase (POD), and catalase (CAT) activities in the foxtail millet initially increased and subsequently decreased; the malonaldehyde (MDA) content increased. Our experiment found that 1/2X and 1X spraying dosages had certain application value in controlling gramineous weeds in foxtail millet field. Other spraying dosages are not recommended as they may harm the crops. Our findings provide reference for identifying new herbicides in the foxtail millet field.

Data-driven computational mechanics: comparison of model-free and model-based methods in constitutive modeling

In computational homogenization approaches, data-driven methods entail advantages due to their ability to capture complex behavior without assuming a specific material model. Within this domain, constitutive model-based and model-free data-driven methods are distinguished. The former employ artificial neural networks as models to approximate a constitutive relation, whereas the latter directly incorporate stress–strain data in the analysis. Neural network-based constitutive descriptions are one of the most widely used data-driven approaches in computational mechanics. In contrast, distance-minimizing data-driven computational mechanics enables substituting the material modeling step entirely by iteratively obtaining a physically consistent solution close to the material behavior represented by the data. The maximum entropy data-driven solver is a generalization of this method, providing increased robustness concerning outliers in the underlying data set. Additionally, a tensor voting enhancement based on incorporating locally linear tangent spaces enables interpolating in regions of sparse sampling. In this contribution, a comparison of neural network-based constitutive models and data-driven computational mechanics is made. General differences between machine learning, distance minimizing, and entropy maximizing data-driven methods are explored. These include the pre-processing of data and the required computational effort for optimization as well as evaluation. Numerical examples with synthetically generated datasets obtained by numerical material tests are employed to demonstrate the capabilities of the investigated methods. An anisotropic nonlinear elastic constitutive law is chosen for the investigation. The resulting constitutive representations are then applied in structural simulations. Thereby, differences in the solution procedure as well as use-case accuracy of the methods are investigated.

Impurity transport in PISCES-RF*

Abstract Linear plasma devices (LPD) utilizing a helicon plasma source, a high density light ion source, can generate impurities due to progressive erosion of the radio frequency (RF) transmission window caused by rectified sheath voltage. These source-born impurities can entrain and be transported by the plasma toward a target, affecting plasma-material interaction studies. Earlier work on material testing in Prototype-Materials Plasma Exposure eXperiment at ORNL revealed significant source impurity deposition on downstream targets. However, using a similar RF source, no target impurity deposition is observed in Plasma Interaction Surface Component Experimental Station (PISCES)-RF despite evidence of RF window erosion in the source region, thereby motivating the present work. Experimentally, using various magnetic field configurations upstream of the PISCES-RF plasma source and seeding titanium (Ti) impurities at various axial locations, impurity transport and deposition along the machine axis were investigated. It was found that Ti deposition was localized to the side of the plasma source where the Ti impurity was seeded. In contrast, aluminum (Al) deposition, originating from the sputtering of the helicon window, occurred predominantly upstream of the plasma source, suggesting an asymmetry in the axial transport of eroded RF window material. These observations suggest a stagnation of the parallel plasma flow immediately downstream of the plasma source, with impurity ions remaining unmagnetized near the source upstream. Al deposition in magnetic field-free regions in PISCES-RF indicates that sputtered Al impurities likely remained neutral due to their large ionization mean-free path under PISCES-RF conditions. Plasma modeling and simulation supported this, indicating that Al-neutrals transport toward the helicon source upstream for low electron density cases. It was found that the Larmor radius of the Al ions was greater than the plasma radius towards the source upstream and remained weakly magnetized in PISCES-RF, meaning that plasma source-born impurities are not efficiently entrained in the plasma flow. These findings provide critical insights into impurity transport in helicon plasma-based LPDs.