Set Of Tests Research Articles

Study on the Effects of Printing Process and Reinforcement Materials on the Performance of 3D-Printed Glass Bead Insulation Mortar.

Based on 3D printing technology, this paper investigates the effects of the printing process and reinforcement materials on the performance of 3D-printed glass bead insulation mortar. In order to improve and enhance the performance of the mortar, two sets of tests were designed for research and analysis. Firstly, by changing the direction of the interlayer printing strips, the anisotropy of the specimens in different paths was analyzed, and then the effect of different dosages of different fibers on the performance of 3D-printed glass bead insulation mortar was investigated by adding reinforcing materials. The results show that the path a specimen in the X direction's compressive strength is the best; in the Y direction, flexural strength is the best; the path b specimen in the Y direction's compressive strength is the best; in the Z direction, flexural strength is the best, but the compressive and flexural strengths are lower than the strength of the specimen without 3D printing (cast-in-place specimen); and adding reinforcing materials mortar not only has high strength but also has good printability and excellent thermal insulation. This paper provides a theoretical basis and reference value for the popularization and application of 3D printing thermal insulation mortar technology.

Evaluation of an x-ray multilayer mirror for radiography at sub-1-keV photon energies.

An x-ray multilayer mirror on a spherical substrate designed for near-normal incidence with a photon energy of ∼738eV (F Heα) was procured and tested. This device is intended to be used for in-flight radiography of the shell in inertial confinement fusion experiments with cryogenic targets on the OMEGA laser at the Laboratory for Laser Energetics. Experiments in self-emission on a small (∼10J) laser system showed that the reflectivity of the mirror is high enough to record an image at laser energies as low as 0.1J. A second set of tests in backlighting geometry on a larger (kJ)-scale, short-pulse laser yielded usable radiographs with laser energies as low as 40J with a spatial resolution of ∼10μm.

THE ROLE OF INTERNAL AUDIT IN IMPROVING THE QUALITY OF FINANCIAL REPORTS

The current research aims to test the impact of internal audit in improving the quality of financial reports within the sample of the study, 230 questionnaires were distributed to auditors and accountants working in companies listed on the Iraq Stock Exchange and were subjected to a set of statistical tests and concluded that the internal auditor has a significant role in improving the quality of financial reports and The importance of users of financial reports in making rational investment decisions and also metrics based on the main characteristics of financial reports are one of the most critical measures of the quality of financial reports.

Failure analysis and comparative study on tunnels under strike-slip fault and oblique-slip fault movements

To deeply study and compare the failure characteristics of tunnels under strike-slip and oblique-slip active faults, with the engineering background of a railway tunnel in western China crossing both strike-slip and oblique-slip active faults, two sets of large-scale indoor model tests with a geometric similarity ratio of 1:35 were conducted. The fissure development patterns and strain trends of the tunnel under the movement of both types of faults were monitored and analyzed. Meanwhile, a three-dimensional model of tunnel-rock-fault interaction was established using ABAQUS finite element analysis software to determine the variation patterns of bending moments and shear forces of the tunnel under the movement of both types of faults. The results showed that under the movement of strike-slip and oblique-slip active faults, circumferential bending fissures appear at the right waist of the hanging wall and the left waist of the footwall of the tunnel, and shear oblique fissures appear at the vault of the fault fracture zone. Among them, the number of cracks, the range of tunnel cracking and the degree of crack damage under the condition of the oblique-slip fault are obviously more serious than those under the condition of the strike-slip fault. Under the dislocation of the oblique-slip fault, a large area of broken zone appears in the vault of the fault fracture zone, the lining falls off, the steel bar is exposed, and there is an obvious uplift phenomenon. The right waist of the tunnel’s hanging wall mainly experiences tension while the left waist experiences compression, whereas on the hanging wall, the right waist experiences compression while the left waist experiences tension. Under the fault movement, the maximum bending moment value mainly occurs at a distance of 10 m from the fault fracture zone on both the hanging wall and the footwall, with the bending moment values at the fault fracture zone nearly approaching zero. The maximum shear force value occurs at the fault fracture zone. Under the movement of both types of faults, the failure mode of the tunnel is mainly characterized by bending failure of the hanging wall and the footwall and shear failure at the fault fracture zone. Compared to strike-slip active faults, the development of fissures in tunnels under oblique-slip active faults is more severe, with larger bending moment and shear force values, and a wider range of tunnel failure. These results can provide theoretical and technical experience for future similar projects.

Fever of Unknown Origin (FUO) Criteria Influences Diagnostic Outcomes: A Systematic Review and Meta-Analysis

BackgroundCriteria classifying fever of unknown origin (FUO) patients remains subject to discrepancies. A minimal standardized set of investigative tests serves as the foundation for the qualitative criteria, whereas quantitative incorporates the length of evaluation (7 or 3 days). A systematic review of studies would help physicians anticipate the frequency of illness types that could influence management. MethodsProspective studies published in Medline (PubMed), Embase, Scopus, and Web of Science databases from January 1, 1997 to July 31, 2022, were included. A meta-analysis estimated associated pooled proportions between these criteria and diagnostic outcomes adjusted to the International Classification of Diseases, 10th edition (ICD-10) definitions. ResultsFive qualitative studies corresponded to an increase of 15.3% (95% CI: 2.3%-28.3%, P = .021) in undiagnosed FUO proportions compared to eleven quantitative studies. Quantitative studies had 19.7% (95% CI: 6.0%-33.4%, P = .005) more in adjusted infectious disease proportions than qualitative studies. No significant differences in proportions between FUO defining criteria were noted for adjusted noninfectious inflammatory disorders (P = .318), oncology (P = .901), non-inflammatory miscellaneous disorders (P = .321), diagnostic evaluation process, gross national income (GNI), or World Health Organization (WHO) geographic region. ConclusionsUse of either qualitative or quantitative FUO criteria was associated with a statistically significant risk of over- or under-estimating infectious diseases and undiagnosed illnesses when using an ICD-10 adjusted FUO five-category system. Clinicians should anticipate differences depending on which criteria are used. While further research is warranted, qualitative criteria provide the best framework for study comparisons.

Transport capacity optimization for high-speed rail network considering flexible train composition and additional capacity pool

To balance the limited capacity and constantly changing demand in the high-speed rail network, a transport capacity optimization problem is investigated by adjusting train composition through uncoupling/coupling operations at the origin station, scheduling additional trains from the capacity pool, and optimizing the seat allocation among ODs. To make joint decisions, a two-stage stochastic programming model is formulated to minimize both operating cost and penalty cost for unsatisfied passengers, while incorporating various constraints such as flow conservation, loading capacity, flexible composition, etc. The two-stage model is linearized into a mixed-integer linear programming model, which can be effectively solved for small networks but is still intractable to solve for realistic networks. Therefore, a Lagrangian relaxation algorithm is proposed integrating parallel computing and sub-gradient method. Finally, two sets of case tests, including a toy network and a real-world case of a high-speed rail network in China, are implemented to show the performance of the proposed approach. The results illustrate that the parallel heuristic algorithm could generate a high-quality solution with a slight discrepancy from the optimal solution, while achieving a commendable computation time. Furthermore, the findings emphasize the advantages of applying flexible train composition and additional capacity pool in the high-speed railway system for cost-saving and supply–demand matching.

Investigating the effects of partitioning temperature fluctuations on the mechanical properties of ASTM A36 carbon steel using Q-P-T heat treatment: an experimental study

In the continuum of time and technological advancement, the use of metals, specifically carbon steel, has significantly increased as primary materials in various operational and industrial domains, including tool fabrication and automotive components. To meet the evolving demands of industries, precise heat treatment processes have been developed to enhance the metallic properties. This study specifically focused on the application of the Quenching-Partitioning-Tempering (Q-P-T) method to ASTM A36 steel. The study investigated different partitioning temperatures, namely 300℃, 350℃, and 400℃, with 15-minute intervals. A comprehensive set of mechanical tests, including hardness, tensile, and microstructural analyses, were conducted to assess the response of the material to the treatment. The results reveal significant findings: a partitioning temperature of 300℃ yields the highest hardness value of 164 Vickers Hardness Number (VHN). Furthermore, the tensile tests demonstrate that a partitioning temperature of 300℃ is optimal, achieving a maximum stress value of 515.73 MPa. Conversely, a partitioning temperature of 400℃ exhibits the highest strain value at 21.08% and the highest elastic modulus value at 11.47 GPa. Microstructural evaluations highlighted the presence of pearlite and ferrite phases, with the partitioning temperature of 300°C displaying the highest proportion of pearlite phase at 38.5%. This meticulous investigation expands our understanding of metallurgy and underscores the intricate relationship between partitioning temperatures and the mechanical properties of ASTM A36 steel. It provides valuable insights for material design and application methodologies and facilitates advancements in industrial practices

Performance evaluation of the SMART passive safety injection system against the SBLOCA scenario with the SMART-ITL facility

A set of system performance tests has been performed and the thermal-hydraulic behaviors were investigated for the passive safety injection system (PSIS) of the SMART design. Major thermal-hydraulic characteristics of core cooling in reactor coolant system and safety injection (SI) in PSIS were investigated using the SMART-ITL. The parametric effects of break size, break location and train number on the PSIS performance were discussed with the relevant SMART-ITL data. Compared with the 2.0 inch SI line break test, the 0.4 inch SI line break test has a milder change of system parameters. The pressure is reduced more quickly, the decrease of water level is slower and the break mass flow rate is higher during the pressurizer safety valve line break than during the SI line break. Major thermal-hydraulic parameters were compared among single, two and full train operation of the PSIS focusing on the effect of train number. It was shown that multiple trains of CMT and SIT were operated independently and the reactor vessel (RV) inventory increased proportionally with the addition of each train. Sufficient SI water was injected into the RV in a passive manner to cool down the reactor core efficiently during the full train test.

Research on electromagnetism scattered from electricity power supply towers based on orthogonal test designs

Abstract For the protection of transmission towers against electromagnetism interference to peripheral radio radar stations, this paper designs orthogonal tests to investigate the electromagnetism scattered efficiency of UHV transmission towers. The towers were mathematically modeled, and the influence of three main factors, tower spacing, frequency, and number of transmitting pylons, on the electromagnetism scattered is investigated. Each factor corresponds to three levels of study and nine sets of orthogonal tests were designed to greatly simplify the number of simulations. Three-factor analysis of variance was undertaken on test data and demonstrated that frequency was the main factor affecting electromagnetic scattering, with tower spacing being the next most influential and many towers the least influential. With the main and secondary effects in mind, the combination with the most significant effect of interaction effects on electromagnetic scattering was selected as the five towers with frequency 1400 kHz and tower spacing 200 m. The investigated outcomes lay the foundation and supply instructions for multi-factor analyses of electromagnetic scattering.

Insights into In Situ Benthic Caging Tests for Ecotoxicity Assessments Targeting Discharging Groundwater Contaminant Plumes

While in situ toxicity testing with caged organisms has been used to assess surface water and sediment contamination, no successful application to benthic organisms exposed to highly contaminated groundwater plumes discharging to surface waters has been reported. The objective of this study was to demonstrate and evaluate this application using four sets of tests performed at three previously reported contaminated groundwater sites, which include one river site affected by volatile organic contaminant plumes, and two sites, one pond and one small urban stream, impacted by landfill plumes. The study examined multiple cage designs and orientations and two test organisms: an amphipod (Hyalella azteca) and midge larvae (Chironomus riparius; only one study). Cages were deployed for between 5 and 28 days and assessed for organism survival and growth. At all sites and for some deployment conditions, cages exposed to high contaminant concentrations in the plume footprint had greater mortality compared to those exposed to lower or background concentrations. Organism growth was less clear as a metric of toxicity. Vertically oriented cages typically showed high mortality to plume contaminants, but some were also affected by other non-target groundwater conditions (e.g., low dissolved oxygen, other contaminant sources), while horizontally oriented cages were rarely responsive to either groundwater influence. A hybrid cage design showed much promise in its single study. Useful observations on the test organisms and on potentially problematic site conditions were also made. The informed use of in situ toxicity cages could be an additional beneficial tool for groundwater contaminated site assessments.

Evolving Efficiency of Cryptocurrency Market: Evidence from Leading Cryptocurrencies

The article investigated the efficiency of the cryptocurrency market, with a focus on Bitcoin (BTC), Ethereum (ETH), Tether (USDT), and Binance Coin (BNB-USD), based on their substantial market capitalization. For this purpose, we observed the daily closing prices spanning from January 2018 to December 2023 and employed a set of robust tests, including the generalized spectral test, automatic portmanteau test, and automatic variance ratio test. The findings of the study reveal a random pattern in price fluctuations, indicating weak form efficiency. Furthermore, we adopted the rolling window approach to investigate whether market efficiency is dynamic or static over time. The empirical result illustrated that the crypto market efficiency remains static over time, except for USDT. In conclusion, the overall empirical results support the notion of the random walk hypothesis, indicating that past price movements offer no predictive insight into future prices. These findings have significant implications for investors, emphasizing the lack of predictive insight from past price movements. Policymakers are urged to establish a robust framework for market integrity and reliable price discovery.

Assessment of the Potential of Elementary School Students in Terms of Physical Fitness

Primary education is an essential foundation for developing all the potential possessed by students, including physical fitness. The persistent inadequacy in children's physical fitness levels raises critical concerns regarding their overall health and well-being, necessitating urgent attention and intervention. This study aimed to assess the physical fitness of elementary school students, evaluate the effectiveness of the Indonesian Physical Fitness Test in measuring their physical fitness, and give policy recommendations. The quantitative descriptive method was used in this study due to its ability to provide numerical data analysis, facilitate systematic measurement, and allow comparative analysis and generalization. Incidental sampling was used to select 120 primary school learners in the Sidoarjo district. Two sets of fitness tests were administered based on child development phases: the Around the World Test for Phase B and a 600m running test for Phase C. Crosstabs analysis on SPSS revealed that male and female learners exhibited similar physical fitness levels, mainly within moderate and healthy categories. Differences were observed based on the phase or grade level (chi-squared=43.843, p=0.000), with Phase B learners generally having moderate to good fitness, while Phase C learners demonstrated lower and middle levels. Overall, there was a decline in fitness with higher grade levels, emphasizing the necessity to rejuvenate physical education for enhanced fitness. Instilling the importance of maintaining and enhancing physical fitness from a young age is crucial, and both teachers and students can actively contribute by enhancing their comprehension of physical literacy through training or by integrating it into the physical education curriculum.

A direct analytical methodology for the assessment of ductile fracture in metals based on multiaxial tests

AbstractThe prediction accuracy of ductile damage models is subject to a sound calibration strategy, which normally involves the execution of complex multiaxial tests and requires dedicated facilities. In addition, finite element (FE) analysis is mandatory to retrieve the stress and strain states at the critical point, which cannot be directly measured from experiments. To overcome this complexity, a minimal set of simple multiaxial tests is selected, and an analytical‐numerical approach is proposed to evaluate, without resorting to FE, both the stress evolution with plastic deformation and the fracture strain, under any different loading condition of each test. This is achieved from the sole knowledge of the material bilinear stress–strain relation and of the applied test displacement at fracture. The obtained results are compared with a traditional testing and calibration methodology, and the robustness of the approach is proved on a 17‐4PH steel, an X65 steel, and a Ti6Al4V alloy.

외국인 중급 유학생의 한국어 음소 인식 및 철자 능력 분석 연구

This study aimed to explored the relationship between basic Korean literacy skills and Korean language proficiency among international students who are learning Korean in a university language institute. Participants’ basic Korean literacy skills were measured by a set of tests including phonemic awareness and spelling. One hundred and eight international students who attended intermediate level Korean language classes participated in this study. The results showed that there was a significant correlation between their basic Korean literacy and Korean language proficiency. In particular, notable correlations with Korean language procificency were observed for basic vowels and the diphthongs ㅑ (ya) and ㅘ (wa), which are integral components of phonemic awareness and spelling tests conducted in a one-syllable (CV) structure. Furthermore, participants’ average accuracy in phonemic awareness test was only 59.92% and the average accuracy in spelling test was 72.48%. Considering that the test items were constructed with basic phonetic features of Korean language and orthography, their Korean literacy skills were found to be pretty limited, which were comparable to the native first-graders in Korea. Authors also compared the basic Korean literacy test scores between two groups who passes language course and who failed the course. The findings revealed that the basic literacy skills of the failed group was significantly lower than that of the passed group, indicating that phonemic awaeness and spelling abilities may affect Korean language proficiency and academic achievements. Authors discussed that Korean literacy of the foreign Korean language students are in needs of atttention among educators and researchers

A Péclet-robust Discontinuous Galerkin method for nonlinear diffusion with advection

We analyze a Discontinuous Galerkin method for a problem with linear advection–reaction and [Formula: see text]-type diffusion, with Sobolev indices [Formula: see text]. The discretization of the diffusion term is based on the full gradient including jump liftings and interior-penalty stabilization while, for the advective contribution, we consider a strengthened version of the classical upwind scheme. The developed error estimates track the dependence of the local contributions to the error on the local Péclet numbers. A set of numerical tests support the theoretical derivations.

Developing Tenth-Grade Students' Problem-Solving Skills in Chemistry through Deductive Learning with the DAPIC Approach

The authentic science classroom requires students to think and solve problems through hands-on activity. This research aims to enhance problem-solving skills in chemistry of grade 10 students through deductive learning with the DAPIC approach, with a passing criterion of 70% or higher of the total score. This research employed action research. The target group consists of 22 students from the model school of Mahasarakham University in the second semester of the academic year 2023. The data collection instruments included nine lesson plans, three sets of essay-type problem-solving tests (each comprising three questions), student interview questionnaires regarding their opinions on learning management, and observational data on problem-solving behavior in chemistry. The research findings indicated that the target group improved their problem-solving skills after learning through deductive learning with the DAPIC approach. In the first cycle, 50% of students (11 out of 22) met the passing criterion of 70%. In the second cycle, 81.82% of students (18 out of 22) passed, and in the third cycle, 95.45% of students (21 out of 22) achieved the passing criterion. It can be concluded that deductive learning with the DAPIC approach can also enhance students' problem-solving in the science classroom.

Do fiscal rules shape private-sector investment decisions?

We investigate whether fiscal rules impact private domestic investment. Using data spanning 100 advanced and developing countries over the period 1990–2019 and applying the entropy balancing method, we reveal that implementing fiscal rules significantly improves private-sector investment. This finding is robust to a wide set of economic and econometric tests. Moreover, we perform a range of heterogeneity tests and find that the effect of fiscal rules only applies in developing countries and is amplified in good times and in countries with a strong fiscal stance. However, the benefits of fiscal rules are mitigated in resource-rich countries and during economic crises. Finally, we explore the underlying mechanisms and show that fiscal discipline, a composition effect fostering public investment, and macroeconomic stability are three driving forces that produce the stimulative effect of fiscal rules.

Assessment of the INRIM trace water generator and analysis of the uncertainty components down to −100 °C frost-point temperature

A low frost-point generator (INRIM 03) able to operate at sub-atmospheric pressure has been recently designed, constructed, and assessed at the Istituto Nazionale di Ricerca Metrologica (INRiM) with the aim of providing the metrological traceability both to instruments developed for the measurement of humidity in atmosphere and to sensors and analysers used in industry for controlling and measuring the amount of water vapour in manufacturing processes. The humidity generator operates in a single temperature single pressure mode, letting the carrier gas (nitrogen) achieve saturation in a single passage through an isothermal saturator. Its working range encompasses a frost-point temperature range from −100 °C to −20 °C, in a pressure range between 200 and 1100 hPa, corresponding to an amount of water fraction range from 13 · 10−9 mol·mol−1 to 6.2 · 10−3 mol·mol−1. In a previous work its performance was assessed in the frost-point temperature range from −75 °C to −20 °C (Cuccaro et al 2018 Meas. Sci. Technol. 29 054002). In this work, a comprehensive set of tests for its characterisation and performance evaluation between −75 °C and −100 °C is presented. A detailed uncertainty analysis in the above temperature range is reported, taking into account all the sources of uncertainty that affect the humid gas generation. An expanded uncertainty (k= 2) of 0.07 °C was found for frost-point temperature measurements between −75 °C and −95 °C, while an expanded uncertainty of 0.26 °C resulted at a frost-point temperature of −100 °C. The relative expanded uncertainty (k = 2) associated with water vapour amount fraction measurements was estimated equal to or better than 1.2% between 35 · 10−9 mol·mol−1 and 6.1 · 10−3 mol·mol−1, increasing up to 6.5% at 13∙10−9 mol·mol−1.

Theoretical nonlinear force-displacement constitutive model of triangular-plate steel damper

Utilizing the inelastic deformation of a steel damper to dissipate seismic energy and control structural damage is a prevalent design strategy in a passive control field. Such a design strategy requires an explicit force-displacement constitutive model of the steel damper in both the elastic and plastic deformation phases. Currently, the nonlinear force-displacement relationship of the steel damper is mainly determined by quasi-static tests or numerical simulations which are generally time-consuming, and there is a lack of a theoretical and straightforward approach to determine the nonlinear force-displacement constitutive model of the steel damper. This study thus theoretically derives the nonlinear force-displacement constitutive model for a commonly used triangular-plate steel damper. The theoretical formula is derived based on the equal curvature assumption commonly applied to the triangular plate and is further modified based on the curvature shape function proposed in this study for the first time. After that, the force-displacement curves obtained from the theoretical formula are compared with those obtained from a large number of numerical simulations and several sets of quasi-static tests. The result shows that the theoretical formula derived based on the curvature shape function can better predict the nonlinear force-displacement curve of the triangular-plate steel damper, which significantly outperforms the theoretical formula derived based on the equal curvature assumption especially as the triangular-plate steel damper has a large plastic deformation. Furthermore, the influence factors of the strain-hardening phenomenon existing in the force-displacement curve of the triangular-plate steel damper are analyzed based on the modified theoretical formula. The result implies that the thickness-to-height ratio of the plate is the most significant factor for the strain-hardening behavior of the triangular-plate steel damper.

Difference in hot deformation behavior of a Ni–Fe based superalloy through cast-wrought and additive manufactured processes

Traditional cast-wrought superalloys have been challenging in cogging due to element segregation. However, additive manufacturing technology is anticipated as a novel method for producing low-segregation superalloys. A set of isothermal compression tests were conducted on a Ni–Fe based superalloy GH4169 in various processing conditions, including as-cast and as-homogenized alloy produced by triple melting (Alloy TMC and TMH), as well as additive manufactured alloy (Alloy AM). Flow stresses were examined to develop activation energy maps and processing maps. Additionally, microstructure evolutions were observed to investigate the mechanisms of recrystallization nucleation and grains refinement during hot deformation. Under specific deformation conditions, three alloys have developed to varying refinement stages. As Zener-Hollomon parameter Z decreases, the nucleation mechanism shifts from continuous to discontinuous dynamic recrystallization. Alloy TMH exhibits enhanced hot workability compared to TMC, which is attributed to its lower activation energy Q and more limited instability region. Q value of Alloy AM is slightly higher than that of TMH; however, it demonstrates a wider processing window. Utilizing AMed superalloys for hot deformation not only provides advantages in low segregation and fine grains, but also simplifies the process sequences. This is expected to break through the current technical bottleneck associated with higher performance superalloy turbine disks.