Test Object Research Articles

Energy efficiency in materials testing by reactive power – part 1: power recirculating method in wear testing

Abstract Reactive power is related to the type of power that does not consume energy but stores it. In the design of test machines, the utilization of this physical phenomenon would be very beneficial. Reactive power allows for the combination of power amplification with energy savings, making it an ideal principle for conducting long-term tests that involve high loads and prolonged energy consumption. This concept is illustrated in this work focusing test machines used in rotary testing procedures. Drive element pairs, which serve as component test objects, are primarily exposed to wear stress. These stressed element pairs are consequently integral parts of a tribological system. The underlying principles of power amplification and power feedback are explained from the perspectives of drive technology, systematic design, methodical design, and mechatronics.

Developmental Trajectory of Autistic-Like Behaviors in a Prenatal Valproic Acid Rat Model of Autism.

Autism spectrum disorders (ASDs) are characterized by deficits in social functioning, stereotyped patterns of behaviors, narrowed interests, and elevated anxiety. Certain ASD symptoms can persist, whereas others may improve throughout the lifespan, but the specific patterns of changes have not been clearly delineated. Using a valproic acid (VPA) rat model of ASD, the present study took a developmental approach and examined how autistic-like behaviors, including anxiety-like behavior, object obsession, and social functioning deficits, manifested differently in three critical periods representing preadolescent (postnatal day [PND] 25), adolescent (PND 45), and adulthood life stage (PND 75) in a sex-dependent manner. Starting on PNDs 25, 45, and 75, VPA- or saline-exposed male and female offspring were tested in an elevated plus maze (EPM) and a newly validated composite social and object interaction and a triple recognition test (object, spatial, and social recognition). Across the three age groups, VPA-exposed offspring did not exhibit enhanced anxiety-like behavior in the EPM nor enhanced object interaction ("object obsession") in the triple recognition test. However, both male and female preadolescent (PND 25) VPA-exposed offspring showed a significantly increased latency to initiate social contact than the saline-exposed controls, although their latencies to contact novel objects were comparable to those of the controls. Male preadolescent and adolescent VPA-exposed offspring, to a lesser extent the female preadolescent offspring, exhibited significantly lower levels of social interaction. These social functioning deficits were absent in adult VPA offspring. Additionally, prenatal VPA exposure did not cause an impairment of object recognition, spatial recognition, or social recognition of a familiar conspecific. Unexpectedly, it enhanced social recognition of a novel conspecific, but only in adolescent female offspring. These findings suggest that this rat model based on prenatal VPA exposure is valid in capturing early social motivational and functioning deficits but is limited in its capacity to model increased object obsession and enhanced anxiety as seen in ASD, as well as the developmental trajectory of non-social ASD symptoms. Recognizing these limitations is important as it informs us how to properly use this model to investigate the neurobiology of ASD and incentivizes us to develop better rodent models.

Fiber-Based Laser Doppler Vibrometer for Middle Ear Diagnostics

Laser Doppler vibrometry (LDV) is an essential tool in assessing by evaluating ossicle vibrations. It is used in fundamental research to understand hearing physiology better and develop new surgical techniques and implants. It is also helpful for the intraoperative hearing assessment and evaluation of postoperative treatment results. Traditional volumetric LDVs require access in a straight line to the test object, which is challenging due to the structure of the middle ear and the way the auditory ossicles are accessible. Here, we demonstrate the usage of a fiber-based laser Doppler vibrometer (FLDV) for middle ear diagnostics. Compared to classical vibrometers, the main advantages of this device are the ability to analyze several arbitrarily selected points simultaneously and the flexibility achieved by employing fiber optics to perform analysis in hard-to-reach locations, which are particularly important during endoscopic ear surgery. The device also allows for a simple change in measuring probes depending on the application. In this work, we demonstrate the properties of the designed probe and show that using it together with the FLDV enables recording vibrations of the auditory ossicles of the human ear. The obtained signals enable hearing analysis.

Design of Controlled Random Tests with the Given Hamming Distance

The article considers the issues of testing computing systems and their components. It shows the low efficiency of probabilistic testing due to the failure to use the available information about both the test object and previously generated test sets. It is noted that it is promising to use information about previous test sets when constructing controlled probabilistic tests. A class of controlled probabilistic tests with a small number of test sets is identified and studied. Known standard controlled probabilistic tests with a small number of test sets are analyzed. A method for generating controlled probabilistic tests with a given Hamming distance is considered, the basis of which is the representation of binary test sets as a set of symbols of other number systems. Providing a given value of the Hamming distance for a controlled probabilistic test in a non-binary number system guarantees the same value for the binary interpretation of the generated test sets. The efficiency of the proposed test construction method is experimentally analyzed and confirmed for the case of testing memory devices for the presence of complex faults of mutual influence.

Research on Production Decision Modelling Based on Sequential Testing and Minimum Objective Planning

In this paper, the decision-making problem encountered by an enterprise in the production process is studied in depth by using the sequential test and the minimum objective planning method. The study begins with a sampling and testing model for spare parts, simplifies the model based on normal distribution, and applies the sequential test technique to reduce the number of necessary samples and effectively optimize the cost of sampling and testing. Immediately after that, we constructed a minimum objective planning model to model the production process of spare parts and finished products and their related costs in detail. We solved the optimal production cost for each of the six real production scenarios faced by the enterprise. The results show that our model can not only effectively reduce production costs, but also significantly improve decision-making efficiency.

The Ability of a Virtual Implantation Device to Evaluate Two Intraocular Lens Designs.

To evaluate the ability of a novel device using virtual implantation to compare the visual performance of two different types of intraocular lenses (IOLs). In this prospective, masked, and randomized clinical trial, the visual performance of monofocal and lowadd bifocal IOLs was compared using a device for virtual implantation called VirtIOL. Eighty patients (< 50 years old with healthy eyes and without cataract) were enrolled in this study. Defocus curve and contrast sensitivity were measured using the Freiburg Vision and Contrast Test (FrACT). Expected defocus curves for the monofocal IOL and the bifocal IOL confirm the utility of the method. The monofocal IOL provided a slightly higher mean visual acuity at 0.00 diopter (D) (mean ± standard deviation: -0.18 ± 0.07 D) compared to the bifocal IOL (-0.16 ± 0.08 D), but also a slightly lower visual acuity from -1.25 to -4.00 D. The mean contrast sensitivity was significantly higher for the monofocal IOL at 7, 11, and 15 cycles per degree. The investigators attest a high usability of the method due to simple communication with the test patient and quick and uncomplicated change of test objects. The visual performance of the monofocal and bifocal IOLs was as expected, with greater depth of focus but reduced contrast sensitivity for the bifocal IOL. The VirtIOL device represents a promising tool to predict the visual performance of IOLs before implantation in patients. [J Refract Surg. 2024;40(12):e911-e915.].

DETERMINING IMPACT VELOCITY IN AN IMPACT TESTER USING A MATHEMATICAL MODEL

Testing on impact test hammer is one of the methods to evaluate the impact of impulses, accelerations, and stress waves on the details and parts of the test object in order to evaluate the operation or durability of the test object for research and testing. Those impacts depend on many factors such as the weight of the hammer, the weight of the test object, the hardness of the anvil, the angle of lifting the hammer, etc. The parameters of the hammer are only applicable to the default cases, other cases when necessary to determine velocity must be measured. The calculation method is suggested by this article to determine impact velocity so that it can be applied on all cases instead of having to measure many times. The calculation results are verified by experimentally measuring the hammer velocity on high-speed camera with an error not exceeding 3.42%.

Experimental model for assessing the effectiveness of radioprotectors in biomedical research

Background. Radiobiological research on chemical radioprotectors is relevant in the study of radiation injuries and in practical medicine during radiation therapy of cancer patients. Selection of the optimal experimental model is necessary to assess the effect of radioprotectors on hematopoiesis and is an important task.The aim. Analysis of the possibility of using Danio rerio fish as a test object for assessing the effectiveness of the protective effect of radioprotectors against ionizing radiation using an erythrocyte micronucleus test.Material and methods. The work was carried out on Danio rerio aquarium fish. Seven groups of two-month-old zebrafish juveniles (n = 35), as well as adult fish, were exposed to X-ray radiation at doses of 0 Gy (control), 1.0 Gy, 2.0 Gy, 3.0 Gy, 4.0 Gy, 6.0 Gy, 8.0 Gy to determine the frequency of occurrence of micronuclei in peripheral blood erythrocytes 72 hours after irradiation.Results. The frequency of occurrence of micronuclei in Danio rerio erythrocytes was dose-dependent. In juveniles, as in adult fish, the dose of ionizing radiation increased to 4 Gy led to a sharp increase in the frequency of occurrence of micronuclei in erythrocytes. Adult Danio rerio were more radioresistant; the number of micronuclei formed in erythrocytes in two-month-old juveniles exceeded the frequency of occurrence of micronuclei in adult fish.Conclusion. A model using juvenile fish Danio rerio as a laboratory test object for assessing the effectiveness of the protective effect of radioprotectors against ionizing radiation using the erythrocyte micronucleus test can be recommended for testing the effect of medications in case of radiation injuries, as well as for assessing the possibility of their use in radiation therapy in cancer patients.

A phantom study on the applicability of a detectability index in ultrasound imaging

The assessment of clinical image quality on ultrasound is currently often subjective. While image quality factors such as contrast response or depth of penetration can be evaluated semi-automatically, the evaluation of high contrast resolution requires test objects with specific inserts. The aim of this study was to evaluate the applicability of image quality metrics which were derived from Linear System Theory in the field of medical ultrasound imaging. Modular Transfer Function (MTF) and noise power spectrum (NPS) were determined on four phantoms. Image quality was assessed using a detectability index for different diameters. One phantom contained a cylinder filled with water, which appears as a circle in the US images. The other three phantoms were homogeneous and consisted of three different materials all based on PVA (polyvinyl alcohol). The basic phantom material was a 10% PVA hydrogel. The two other materials included microplastic spheres and starch to increase echogeneity. NPS and the MTF were determined using MATLAB routines. Two linear US transducers with bandwidths of 2.4–10 and 4–15 MHz were used to show the dependence of the index on the principal frequency of the US wave. The results show that for all phantom materials and object sizes (1–10 mm diameter), the detectability indices decreased with increasing penetration depth (from 6 to 10 cm). In addition, all indices of the higher frequency transducer were higher than those of the lower frequency transducer. When comparing the different phantom materials (PVA, PVA with starch and PVA with microspheres), different mean pixel value (MPV) were found, while the standard deviations for the materials were similar. This enabled us to evaluate the detectability index at different signal-to-noise ratios (SNR). Measures of image homogeneity (coefficient of the variance and variation) showed no significant difference to a commercial phantom (p-values ranging from 0.16 to 1, average p-value 0.5). These results suggest that the concept of a detectability index can also be applied to US imaging.

Development of a Mathematical Model of the Self-Shielded Flux-Cored Arc Surfacing Process for the Determination of Deposition Rate.

The article presents a method of developing a mathematical model of the arc surfacing process performed using the self-shielded flux-cored filler metal wire with the chromium cast iron (Fe15) weld deposit. A three-level design (static, determined, and complete) was used to determine the function of the test object, thus enabling the simulation of deposition rate in relation to wire feed speed and electrode extension. The deposition rate for the specified set of surfacing parameters amounted to between 4.31 kg/h and 11.25 kg/h. The study was also concerned with identifying the effect of the significance level of test factors and interactions between them on the resultant factor, as well as an assessment of the adequacy of the test object function. In relation to significance level α = 0.01, regression coefficients b0, b1, b2, and b11 significantly affected the deposition rate of the surfacing process. Coefficient b22 was significant at a level of 0.40, whereas coefficient b12 was significant at a level of 0.15. The mathematical model presenting the effect of wire feed speed and electrode extension, as well as interactions between them on the deposition rate of the surfacing process, was adequate for the adopted level of significance α = 0.05.

Detection of Diffusion Interlayers in Dissimilar Welded Joints in Processing Pipelines by Acoustic Emission Method

The paper considers the neural network application to detect microstructure defects in dissimilar welded joints using the acoustic emission (AE) method. The peculiarity of the proposed approach is that defect detection is carried out taking into account a priori information about the properties of the AE source and the acoustic waveguide parameters of the testing structure. Industrial process pipelines with dissimilar welded joints were studied as the testing object, and diffusion interlayers formed in fusion zones of welded joints were considered microstructure defects. The simulation of AE signals was carried out using a hybrid method: the signal waveform was determined based on a finite element model, while the amplitudes of AE hits were determined based on a physical experiment on mechanical testing of dissimilar welded joints. Measurement data from industrial process pipelines were used as noise realizations. As a result, a data sample was formed that considered the parameters of the AE source and the parameters of the acoustic waveguide with realistic noise parameters and a signal-to-noise ratio. The proposed method allows for a more accurate determination of the waveform, spectrum, and amplitude parameters of the AE signal. Greater certainty in the useful signal parameters allows for achieving a more accurate and reliable classification result. When using a backpropagation neural network, a percentage of correct classification of more than 90% was obtained for a data set in which the signal-to-noise ratio was less than (−5 dB) in 90% of cases.

ASSESSMENT OF PHOTOGRAMMETRY TECHNIQUES FOR 3D MODEL ACQUISITION: A COMPARATIVE STUDY ON THE ACCURACY AND SUITABILITY OF SCANNED MODELS COMPARED TO CAD REFERENCES

This paper presents a comprehensive evaluation of the accuracy of 3D scanning methods using various devices and software to generate 3D models. The resulting models were compared to their corresponding Computer-Aided Design (CAD) models to quantify discrepancies. The primary objective was to assess potential errors, benefits, and limitations of each scanning method, providing insights for future research and development. A switch, chosen as the test object for its moderate complexity and size, enabled a thorough assessment under realistic conditions. The analysis reveals the strengths and limitations of each scanning method, guiding researchers and developers in selecting the most suitable techniques for specific applications. Additionally, the study underscores the importance of device and software parameters on the accuracy of 3D models, offering a comprehensive evaluation of effective techniques for 3D model.

The Effect of Alkali Activator to Binder Ratio on Workability, Density, and Compressive Strength of Fly Ash-Slag Based Geopolymer Mortar

The purpose of this study is to investigate the influence of variations in the alkali activator to binder ratio (Al/Bi) on the workability, density, and compressive strength of geopolymer mortar. This study used an experimental approach to assess mortar compressive strength and workability utilizing a flow table in accordance with SNI 03-6825-2002, as well as mortar density in accordance with SNI 1973-2016. Variations in the Al/Bi ratio used are 0.40, 0.45, 0.50, and 0.55, with a slag content of 20% and a ratio of sodium silicate to sodium hydroxide (SS/SH) 1.5. The materials used in this research are fly ash type F, slag, fine aggregate, and an alkali activator consisting of sodium hydroxide (SH) and sodium silicate (SS). The specimen is in the shape of a cube with dimensions of 50x50x50 mm and a total of 16 test objects. The results show that the higher the Al/Bi ratio, the workability of the geopolymer mortar increases, but the density decreases. The higher the Al/Bi ratio, the compressive strength of the geopolymer mortar increases to an optimal Al/Bi ratio of 0.50. At an Al/Bi ratio of 0.40, it has workability in accordance with SNI 03-6825-2002 standards. All variations of the Al/Bi ratio produce density that meets the SNI 1973-2016 standards. The maximum compressive strength of the geopolymer mortar was 12.15 MPa at an Al/Bi ratio of 0.50.

Psychological testing in the profession of psychology: an Australian study

ABSTRACT Objectives In Australia, psychological measurement and testing is a core competency for all registered psychologists. This study aimed to provide a current perspective on the views of Australian psychologists in the use of psychological testing given the lack of recent Australian research. Method Psychologists (N = 821) completed online a demographic form and the European Federation of Psychologists’ Associations (EFPA) questionnaire on Test Attitudes of Psychologists – Modified (EQTAP-M), refined for the Australian setting. Constructs addressed in the survey included test appreciation, training, technology-based testing, attitudes to test use, and self-rated competence. The sample mean age was 50 years, with 84% over 34 years and 20% being males. Results Attitudinal differences, based on demographics and practice endorsement area, were examined. Partial support was obtained for the factorial model of previous EFPA studies. There was no difference in attitudes based upon the gender of the psychologists, but older psychologists reported less favourable attitudes and lower competence for psychological testing. Psychologists holding endorsements in organisational psychology, neuropsychology, and educational and developmental psychology indicated more positive testing attitudes and appreciation than other areas of practice. The application of technology in assessment was identified as an area that warrants further investigation and training. Conclusions The outcome has theoretical and practical implications for professional bodies and educational institutions that develop policies and training programs relevant to psychological measurement and testing.

Analytical Evaluation of the WebSocket and WebTransport Protocols for the Class of SCADA Systems Operating Within the Intranet

The purpose of research. In recent years, web technologies have been actively used in many process control systems, including SCADA. Such systems allow continuous monitoring of the test object in real time. In this regard, there is a need for frequent data transmission for their further display. To solve this problem, network protocols are used, which continue to develop rapidly to this day.Materials and methods. SCADA systems are used in many industries: aviation, ground transportation, rocket and space technology, systems for receiving and processing telemetry information. Among them, a class of SCADA systems operating within the intranet stands out. This can be an internal network of the enterprise, a hangar or a small test stand for tracking the indexes of measuring equipment. Therefore, today, more than ever, open and publicly available materials are important for understanding modern network solutions that reduce the time spent on data transmission and their further visualization. Such information will be of particular value to students studying network and web technologies.Results. As a result of the research, taking into account the limitations of the SCADA system and network being developed, the time characteristics for the WebSocket and WebTransport protocols have been determined, and the most optimal solution for a typical load is proposed. In the presented paper, the issues of data transfer between the client and server parts for a class of SCADA systems operating within an intranet are considered. In this regard, it is proposed to consider the two most suitable solutions for this task. These are application layer network protocols of the OSI model: WebSocket and WebTransport. In addition, transport layer protocols (TCP and QUIC) are taken into account, since they can also affect time characteristics. Data transmission issues are considered in the context of the SCADA data display and monitoring system. The server part is developed using C#, and the client is developed using JavaScript. A number of experiments are carried out for boundary cases and typical loads, on the basis of which the dependence of data transmission time on their volume is determined.Conclusion. The approach given in the paper on collecting network traffic and analyzing time characteristics will also be useful as part of the educational process for teaching students in the courses “Computer Networks” and “Internet Technologies”.

Architecture Independent Test Templates for Virtual Machines and Microprocessors

To ensure the quality of compilers, virtual machines and microprocessors, testing with the use of test programs is applied. Test templates, i.e. parameterized descriptions of test programs, are used to reduce the resources spent on test creation. For verification of test objects with different architectures, test templates testing the same functional properties can be used. A task of describing templates in an architecture-independent form and its customization for a target architecture arises. The paper proposes a method for creating and using architecture independent test templates. The method is as follows. Architecture dependent constructs that are needed to describe a test template are defined. Based on these constructs, an architecture independent test template is created. Then the template is customized to the architecture of the object under test by describing implementations of the architecture dependent constructs. Realizations of the constructs can be described by different sets of architecturally dependent operations, differing both by the type of data used and by the operations used. Different strategies for selecting the implementations to be used, such as full brute force, random selection, and others, can be applied in the test templates. Providing an interface as the architecture dependent constructs allows the use of third-party generators to create the architecturally independent templates. Rewriting the implementations of the constructs allows the test programs to be derived from the given templates for new architectures. This method was successfully applied to check optimizations in a virtual machine compiler.

Gravitational waves of nonextremal Kerr black holes from conformal symmetry

In the low-energy limit, the near region of a generic Kerr black hole has been conjectured to be holographically dual to a two-dimensional conformal field theory. In this paper, we consider a test object orbiting in the near region of a nonextremal Kerr black hole. We first couple it to a massless scalar field. The resulting scalar radiation at the horizon is computed from the perspectives of gravity and dual conformal field theory. Considering the influence of nonzero temperature, the agreement of both computations is found. Then, we generalize the analysis to the gravitational radiation and find agreement again. The agreement supports the conjectured holography and provides a potential theoretical tool for gravitational wave computations. Published by the American Physical Society 2024

Evaluation of the effect of artificial intelligence training equipment in physical training of table tennis players from a biomechanical perspective

In table tennis competitions, the movement data of table tennis players plays an important role in daily training. In recent years, artificial intelligence technology has been widely used in sports competitions. With the development of artificial intelligence, how to use artificial intelligence to analyze sports video to obtain sports data of athletes has become more and more important. This paper is to use artificial intelligence to research and analyze the athletes in the table tennis competition, and then obtain the sports data of the athletes. This has important guiding significance for athletes and coaches in their daily training. Table tennis is a widely developed sport in China, and as China’s “national ball”, table tennis has always been in a leading position in the world table tennis competitions. It is widely loved by the public for its simple and easy access to sports facilities, low site requirements and sports methods. In this study, mathematical statistics and experimental methods were used. Combined with the application of the functional sports screen function test, 20 table tennis players from Shandong Sport University were selected as the test objects, and their sports performance was tested. The total score of 10 first-level athletes was 162 points, and the average score was 16.2 points. The total score of the 10 second-level athletes was 144 points, and the average score was 14.4 points. The performance of the first-level athletes was significantly higher than that of the second-level athletes. It showed that the first-level athletes were generally better than the second-level athletes in all aspects.

STEWART PLATFORM MULTIDIMENSIONAL TRACKING CONTROL SYSTEM SYNTHESIS

Context. Creating guaranteed competitive motion control systems for complex multidimensional moving objects, including unstable ones, that operate under random controlled and uncontrolled disturbing factors, with minimal design costs, is one of the main requirements for achieving success in this class devices market. Additionally, to meet modern demands for the accuracy of motion control processes along a specified or programmed trajectory, it is essential to synthesize an optimal control system based on experimental data obtained under conditions closely approximating the real operating mode of the test object. Objective. The research presented in this article aims to synthesize an optimal tracking control system for the Stewart platform’s working surface motion, taking into account its multidimensional dynamic model. Method. The article employs a method of a multidimensional tracking control system structural transformation into an equivalent stabilization system for the motion of a multidimensional control object. It also utilizes an algorithm for synthesizing optimal stabilization systems for dynamic objects, whether stable or not, under stationary random external disturbances. The justified algorithm for synthesizing optimal stochastic stabilization systems is constructed using operations such as addition and multiplication of polynomial and fractional-rational matrices, Wiener factorization, Wiener separation of fractional-rational matrices, and the calculation of dispersion integrals. Results. As a result of the conducted research, the problem of defining the concept of analytical design for a Stewart platform’s optimal motion control system has been formalized. The results include the derived transformation equations from the tracking control system to the equivalent stabilization system of the Stewart platform’s working surface motion. Furthermore, the structure and parameters of the main controller transfer function matrix for of this control system have been determined. Conclusions. The justified use of the analytical design concept for the Stewart platform’s working surface optimal motion control system formalizes and significantly simplifies the solution to the problem of synthesizing complex dynamic systems, applying the developed technology presented in [1]. The obtained structure and parameters of the Stewart platform’s working surface motion control system main controller, which is divided into three components W1, W2, and W3, improve the tracking quality of the program signal vector, account for the cross-connections within the Stewart platform, and increase the accuracy of executing the specified trajectory by increasing the degrees of freedom in choosing the controller structure

Automated self-adjustment of array probe with a robotic ultrasonic test system

Ultrasonic testing of objects with complex geometries often requires the use of a robotic arm to position the probe perpendicular to the local surface. Using immersion makes it possible to test these objects with standard ultrasonic linear array probes. Here, the probe positions and orientations provided by the robot are used for merging the locally acquired image data into a 3D-reconstruction. The quality of this reconstruction is highly dependent on the alignment of the position of the physical probe with the position used in the digital model. For common industrial tools, the tool center point (TCP) is usually acquired using geometric features of the tools. However, for ultrasonic arrays in immersion, there is a water standoff between the probe and the test object, therefore the TCP is in free space in front of the array and cannot be acquired with the common method. To overcome this challenge, we propose a method that allows the robotic ultrasonic system to automatically self-adjust the position and orientation of the ultrasonic probe using a test block made of steel with defined geometric features as a target for referencing. For each of the six degrees of freedom, a scan and adjustment routine are established using the data based on the actual ultrasound characteristics of the probe. Given a coarse pre-definition of the tool position and the known target test block, minimal human interaction is required to supervise the adjustment method, leading to higher quality reconstructions than with manual adjustment.