Test Object Research Articles

Study on in situ mass spectrometry leak detection technique of working fluid in spacecraft electric propulsion system

Helium mass spectrometry leak detection technology requires that the leak detection medium of spacecraft test object is helium, but the general working medium of spacecraft electric propulsion system is xenon. The existing helium mass spectrometry leak detection technology can not realize the in-situ leak detection of all kinds of working media. The in situ mass spectrometry leak detection technology of spacecraft working medium based on mass spectrometry has been widely concerned for its advantages of direct leak detection of working medium and obtaining real leak rate, but the sampling and leak detection of mass spectrometry under atmospheric environment is one of its difficulties. In this paper, a leak detection model and test system of spacecraft working medium in situ mass spectrometry are established, and theoretical and experimental studies are carried out. The research results show that, The leak detection sensitivity of in situ working mass spectrometry is better than 1.0 × 10−8 Pa m3/s by shunt current limiting sampling method in atmospheric environment. The appropriate shunt pumping speed and shunt chamber pressure have important influence on in situ leak detection of working medium. When the pressure of capillary shunt chamber is higher than 550Pa, the test system has better stability and repeatability. Not only the background noise of the leak detection by mass spectrometry is reduced, the detection accuracy is improved, and the response time of the system is shortened.

PEMANFAATAN FLY ASH DAN BOTTOM ASH PLTU REMBANG UNTUK PEMBUATAN BETON MENGGUNAKAN SEMEN PPC

The research aims to reduce the amount of coal burning waste of fly ash and bottom ash PLTU Rembang as a substitution of cement and sand in the production of quality concrete K-225 and waterproof using Portland Pozzolan cement. The method was experimented in the laboratory by making 50 samples of 15 x 15 x 15 cm3 test objects for 28 days, 60 days, and water absorption tests. The test objecte was made in 5 variations: normal concrete (without substitution) and 20% bottom ash substitution concrete and fly ash mixture 0%, 5%, 10%, 15%. Strong K-225 pressure occurs at the age of 60 days on bottom ash substituted concrete 20% with fly ash 0%, 5% 10% and 15% respectively of 245 kg/cm2, 254,67 kg/cm2, 250,67 kg/cm2, dan 250,67 kg/cm2. Water absorption of concrete at 28 days of ashes substitution was less than 20% and ashes flew below 0% and 5%, 10% 15% resulted in 4.85%, 5.17%, 5.05%, and 5.18%. The results of the research showed that the concrete made meets the K-225 quality and better absorption than normal concrete.

PENGARUH SERBUK BATU PARAS BELAYU SEBAGAI SUBSTITUSI SEMEN TERHADAP KUAT TEKAN BETON

Cement is the most important building material in making concrete, cement is formed from the oxidation process or heating of limestone using coal at high temperatures. The heating process produces excess CO? which has a negative impact on the environment. So in this research, the researchers conducted research on the effect of sandstone powder (SBP) as a substitute for Portland cement (SPI) in concrete mixtures because sandstone contains silica and alumina minerals which are suitable for use. as pozzolan. The test object used in this study was a cube measuring (150 x 150 x 150) mm, with the ratio: (0% SBP: 100 SPI), (2.5% SBP: 97.5% SPI), (5%SBP: 95% SPI) and (10% SBP: 90% SPI) which were tested at 28 days of age. Concrete mix planning (mix design) is carried out based on SNI 7656-2012 with concrete design quality 20.75 MPa, classified as concrete quality for building structures. From the test results, it was found that the effect of sandstone powder as a cement substitute in the concrete mixture increased the compressive strength of the concrete at a percentage of 2.5% -5%, and at a percentage of 10% the compressive strength of the concrete decreased.

The Influence of Professionalism, Locus of Control, Emotional Intelligence and Professional Ethics on BPR Audit Quality with Ambiguity as a Moderator

As an independent party, auditors have the opportunity to improve the quality and reliability of company financial reports that are used by stakeholders in making decisions. Against this background, incidents relating to the accounting profession from an audit quality perspective are increasing. Incidents often occur with test objects due to the inspector's incompetence. The loss of public trust in the accounting profession is an indication of the loss of AI's strict internal audit concept and a weak governance system. This research aims to determine how professionalism, locus of control, emotional intelligence, and professional ethics influence audit quality. auditors who participated in this research working in BPR Region III in Cirebon, West Java, were used as respondents. The resulting sample consisted of 49 of the 83 research topics selected to represent BPR researchers. The results show problems with normality, multicollinearity, and autocorrelation in the classical assumption test, which consists of normality, multicollinearity, and heteroscedasticity tests using a one-stage multivariate model. The remainder is influenced by other invisible variables, with a total influence of 0.598 or 59.8%.

Effect of naringin on sodium fluoride‑induced neurobehavioral deficits in Wistar rats.

There is a lack of treatment for the detrimental effects of fluorosis. Sodium fluoride at a concentration of 10 ppm induces stress, depression and memory impairment in adult Wistar rats. Naringin, a flavanone glycoside isolated from citrus fruits such as lemons and oranges, possesses anti-inflammatory, antioxidant and neuroprotective properties; therefore, it was used for treatment of fluoride induced toxicity in the present study. Adult Wistar rats were divided into eight groups (n=8). The normal control (NOR) group was provided with normal tap water. The sodium fluoride (FLU)10 group received water containing 10 ppm sodium fluoride for 60 days. The treatment groups (FLU10NAR100 and FLU10NAR50) received drinking water with 10 ppm sodium fluoride ad libitum along with Naringin 100 and 50 mg/kg body weight (bw) per oral gavage, respectively. The NAR100 and NAR50 groups received Naringin 100 and 50 mg/kg bw. The PRONAR100 and PRONAR50 groups received Naringin 100 and 50 mg/kg bw for the first 15 days and then subsequently received FLU10 ppm for 60 days (total of 75 days). All animals were subjected to behavioural tests consisting of the open field test (OFT), forced swim test (FST) and novel object recognition test (NORT). After euthanasia, the hippocampus and prefrontal cortex were stained with Cresyl violet. To measure the oxidative stress caused by fluoride and its effect on antioxidant levels, estimation of reduced glutathione (GSH) by Ellman's method, lipid peroxidation (LPO) measured in terms of the MDA:thiobarbituric acid reaction and catalase was performed. To evaluate the effect of fluoride on activity of acetylcholine, estimation of acetylcholinesterase (AChE) by Ellman's method was performed. In NORT and FST, significant changes (P<0.05) were present in the FLU10NAR100 and FLU10NAR50 groups compared with the FLU10 group, showing recovery from memory deficit and depression. The OFT results were insignificant. The LPO was reduced in all the other groups except the FLU10 group, with statistically significant changes. Catalase activity was significantly lower in FLU10 as compared with the NAR100, NAR50, PRONAR100 and PRONAR50 groups. GSH and AChE activities did not show significant changes as compared with the FLU10 group. The CA3 and prefrontal cortex viable and degenerated neuron count in the FLU10 group were insignificant compared with all other groups, except for the NAR100 and NAR50 groups. Thus, Naringin can be a useful drug to avoid the neurological effects of fluoride.

Cheonwangbosimdan mitigates post-traumatic stress disorder-like behaviors through GluN2B-containing NMDA receptor antagonism in mice

Ethnopharmacological relevanceCheonwangbosimdan (CWBSD), a herbal medicine traditionally used for anxiety, insomnia, depression, and heart palpitations, has been reported to have anti-anxiety, antidepressant, cognitive improvement, and neuroprotective effects. Aim of the studyThe purpose of this study was to determine if CWBSD could affect post-traumatic stress disorder (PTSD)-like behaviors because it has prioritized clinical use over mechanism study. Materials and methodsA single prolonged stress (SPS) mouse model, a well-established animal model of PTSD, was used to investigate whether standardized CWBSD could mitigate PTSD-like behaviors through robust behavioral tests, including the elevated plus-maze test and marble burying test for measuring anxiety-like behaviors, the splash test, forced swimming test, and tail suspension test for evaluating depression-like behaviors, and the Y-maze test and novel object recognition test for assessing cognitive function. Additionally, a fear extinction test was employed to determine whether CWBSD might reverse fear memory extinction deficits. Amygdala tissue was isolated from SPS-treated mouse brain and subjected to Western blotting or quantitative PCR to explore mechanisms by which CWBSD could mitigate PTSD-like behaviors. ResultsCWBSD ameliorated emotional impairments and cognitive dysfunction in an SPS-induced PTSD-like mouse model. It also mitigated deficits in abnormal fear memory extinction. Protein expression levels of N-methyl-D-aspartate (NMDA) receptor subunit 2B (GluN2B) and phosphorylation levels of Ca2+/calmodulin-dependent protein kinase II in the amygdala were increased in SPS model mice and normalized by CWBSD. Additionally, co-administration of CWBSD and GluN2B-containing NMDA receptor antagonist, ifenprodil, at each sub-effective dose promoted fear memory extinction. ConclusionsCWBSD can alleviate SPS-induced PTSD-like behaviors by normalizing GluN2B-containing NMDA receptor activity in the amygdala. Therefore, CWBSD could be a promising candidate for PTSD treatment with fewer adverse effects and better efficacy than existing therapies.

Photothermal performance of vitreous products from high-temperature melting of hazardous waste

High-temperature molten vitreous (HTMV), as the primary means of hazardous waste disposal, was produced in large quantities. Exploring its potential in photothermal applications could extend its high-value. Herein, the HTMV was used to explore the photothermal performance potential. It indicates that the HTMV possesses significant photothermal conversion capability, capable of increasing the tested water temperature by 6.65 °C. The HTMV mass and water volume are critical factors affecting the water temperature outcomes. The HTMV exhibits distinct conversion capabilities when applied at different application scenarios on the test object. Application on the bottom primarily focuses on photothermal conversion with high heat production efficiency, while side application additionally demonstrates excellent thermal insulation properties. Based on heat balance and backpropagation neural network predictions, optimal scheme of HTMV on both inside and outside bottom application scenarios of the heated object can achieve a maximum heat input of 660.6 kJ m−2 and 570.1 kJ m−2, respectively, and reduce carbon emissions by 0.062 kg CO2 m−2 and 0.054 kg CO2 m−2. This study not only provides a foundation for the further application of HTMV but also opens a new direction for the development of photothermal conversion materials, which is of great significance in advancing sustainable energy technology.

The influence of test illuminance on visual acuity in patients with primary open-angle glaucoma and age-related macular degeneration

PURPOSE. To study the influence of the illuminance level of test objects on the resolution of the visual analyzer in patients with primary open-angle glaucoma (POAG) and age-related macular degeneration (AMD), and assess the possibility of using the obtained results for early diagnosis of these eye diseases.METHODS. Visual acuity (VA) under controlled illumination conditions (from 50 to 400 lx) of test objects was assessed using the developed device in three groups: in 50 healthy subjects aged 37.08±10.19 years without ophthalmic pathology (group A), in 50 patients with early (Ia and IIa) stages of POAG aged 47.16±8.28 years (group B) and 50 patients aged 46.08±4.56 years (group C) with dry form of AMD (initial stage).RESULTS. With an increase in the illumination of test objects (IT) from 50 to 400 lx, the VA of healthy individuals significantly increases on average by δ=0.32 (from 1.0±0.22 to 1.32±0.24, p&lt;0.01), while in POAG the increase in VA with an increase in IT is much less pronounced, averaging δ=0.12 (from 0.9±0.20 to 1.02±0.26, p&lt;0.05). At the same time, starting from IT 150 lx and above, the differences between the values of VA in the control group and in the group of patients with POAG of the initial stages become significant (p&lt;0.05). VA of patients with AMD with increasing IT practically does not change, remaining at a stable level: δ=0.04 (from 0.76±0.20 to 0.80±0.26, t=0.66, p&gt;0.5). At the same time, the VA values in this group of patients for each illumination level are significantly lower (p&lt;0.05) than the corresponding VA values in the control group (group A).CONCLUSION. The revealed regularities can be used for early diagnosis of the pathological process: an increase in VA at the maximum level of IT relative to the initial value by less than δ≤0.2 indicates pathology of the optic nerve (POAG), and the absence of significant changes in VA with an increase in IT (minimum values of δ) is characteristic of the pathological process in the macula (AMD).

Estimation accuracy of bean bags as portion size estimation aids for amorphous foods

Objective: A study was undertaken to explore the portion size estimation accuracy of bean bags as low-cost volumetric portion size estimation aids for amorphous foods. Designs: Three observational, cross-sectional and three experimental/quasi-experimental developmental evaluation sub-studies were carried out. Settings: Observational, cross-sectional: one retirement village and four schools. Experimental/quasi-experimental: one South African university. Participants: Observational, cross-sectional: elderly persons, adult women (school educators), schoolchildren. Experimental/quasi-experimental: university students. In total N = 541; > 3 800 observations. Variables measured: Using a standardised set of bean bags (test object; volume range: 60–625 ml), volumes of different amorphous foods (reference objects: actual foods or representations) in varying portion sizes had to be estimated. Accuracy (outcome measure) was perfect if volumes of test and reference object were identical. Acceptable estimation accuracy allowed for misestimation by one bean bag size. Test–retest reproducibility was also assessed. Analysis: Descriptive statistics (proportions perfect and acceptable accuracy). Results: Across the sub-studies, perfect accuracy ranged from 22–65% depending on participants, reference food and portion size. Irrespective thereof, acceptable accuracy was noted in > 70% of observations. Reproducibility varied (range: 28–67% agreement). Conclusions and implications: Perfect portion size estimation of amorphous foods remains challenging. When misestimation by 60–125 ml still serves the purpose of a dietary assessment, bean bags show promise for cost-effective food volume quantification, especially on group level in resource-limited settings.

Ensuring cybersecurity of FPGA as a service with the use of penetration testing of components

The subject of study in this article is modern penetration testing technologies, in which the test object is the implementation of a service based on a platform using Field Programmable Gate Array (FPGA) resources. The goal of this study is to improve modern methods of penetration testing of services provided by FPGA as a Service (FaaS) to find vulnerabilities for further fixing and increasing the level of services security and trust. Task: to analyze the technological capabilities for the development of FPGA as a Service; to analyze possible threats for FPGA as a Service platform; to analyze the structure of the FPGA as a Service platform and the peculiarities of attacks on it; to analyze options for using the penetration testing standard; to propose the classification of possible use of FPGA as a Service platform for solving of cybersecurity tasks; and to propose the sequence of critical components of ensuring of the cybersecurity of FPGA as a Service platform. The following results were obtained based on the tasks. The analysis of the capabilities of existing chips, FPGA accelerator cards, programming technologies, and the integrated environments of a leading company for creation of FPGA as a Service is performed. A study on the cybersecurity problems of FPGA as a Service platforms is conducted, and a set of components to ensure the cybersecurity of FPGA as a Service Platform is proposed. Modern cybersecurity threats of FPGA as a Service platforms are analyzed. A threat structure for FPGA as a Service is proposed. The possibility of applying a penetration testing standard to FPGA services is considered. Regular audits and penetration testing are crucial elements of a cybersecurity strategy and help maintain customer and user trust in FPGA services. Based on the analysis of the possible use of FPGA as a Service to solve cybersecurity tasks, a classification of five variants considering FPGA as an object and tool is proposed. The sequence of critical components of ensuring of the cybersecurity of FPGA as a Service platform is proposed to correspond to modern known threats. Complex activities, including the software updates, security monitoring, auditing, and penetration testing, based on security standards. Conclusions. The primary contribution and scientific novelty of the obtained results is the research into the possibilities of penetration testing for services, where the test object is a platform with access to FPGA. As in many other areas, ensuring the cybersecurity of FPGA as a Service platform is complex, and ignoring any component can lead to critical consequences. Applying only penetration testing is not enough; therefore, a comprehensive list of cybersecurity measures for FPGA as a Service platforms is provided, underlining the urgency and necessity of their implementation.

A New Axial Compressor Test Facility for the Investigation of Aerodynamic Damping Featuring an Electromagnetic Excitation System

Abstract Aerodynamic damping simulations involving detailed computational fluid dynamics (CFD) models are nowadays an integral part of turbomachinery design processes, thanks to advancements made in simulation tools and in computer hardware over the last decades. However, the test cases available in the open literature suitable for the validation and continued development of simulation tools is rather limited. On this background, a new test facility is introduced that allows acquiring relevant and high-quality aerodynamic damping test data on axial compressor rotor test objects in a controlled manner. The test facility is built as a closed loop and thus enables operation at variable pressure levels ranging from near-vacuum to overpressure and with different operating media. Overall damping test data are acquired at controlled synchronous and nonsynchronous vibration conditions. While vibrations of the blades at controlled nonsynchronous vibration conditions can be introduced in the test facility by means of a proprietary electromagnetic excitation system that is acting below the hub line, vibrations at controlled synchronous conditions can be introduced from a set of magnets integrated into the casing. Great care has been spent to create a clean test case without any intruding parts or openings in the test section. In addition, an axial compressor blisk is presented, which acts as test object to show the capabilities of the test facility as well as to allow for detailed investigations of aerodynamic damping. While the first part of the article discusses the setup and the instrumentation of the test facility to excite and measure blade vibration in a nonintrusive way, flow-field measurements and the validation accompanying steady-state Reynolds-averaged Navier-Stokes (RANS) simulations are shown in the second part. The third part of the article focuses on aerodynamic damping measurements for seven different modes at three different pressure levels in total. It can be shown that aerodynamic damping is by far the largest contributor to the overall damping.

High space–time bandwidth product imaging in low coherence quantitative phase microscopy

Current low coherence quantitative phase microscopy (LC-QPM) systems suffer from either reduced field of view (FoV) or reduced temporal resolution due to the short temporal coherence (TC) length of the light source. Here, we propose a hybrid, experimental and numerical approach to address this core problem associated with LC-QPM. We demonstrate high spatial resolution and high phase sensitivity in LC-QPM at high temporal resolution. High space–time bandwidth product is achieved by employing incoherent light source for sample illumination in QPM to increase the spatial resolution and single-shot Hilbert spiral transform (HST) based phase recovery algorithm to enhance the temporal resolution without sacrificing spatial resolution during the reconstruction steps. The high spatial phase sensitivity comes by default due to the use of incoherent light source in QPM which has low temporal coherence length and does not generate speckle noise and coherent noise. The spatial resolution achieved by the HST is slightly inferior to the temporal phase-shifting (TPS) method when tested on a specimen but surpasses that of the single-shot Fourier transform (FT) based phase recovery method. Contrary to HST method, FT method requires high density fringes for lossless phase recovery, which is difficult to achieve in LC-QPM over entire FoV. Consequently, integration of HST algorithm with LC-QPM system makes an attractive route. Here, we demonstrate scalable FoV and resolution in single-shot LC-QPM and experimentally corroborate it on a test object and on both live and fixed biological specimen such as MEF, U2OS and human red blood cells (RBCs). LC-QPM system with HST reconstruction offer high-speed single-shot QPM imaging at high phase sensitivity and high spatial resolution enabling us to study sub-cellular dynamic inside U2OS for extended duration (3 h) and observe high-speed (50 fps) dynamics of human RBCs. The experimental results validate the effectiveness of the present approach and will open new avenues in the domain of biomedical imaging in the future.

Enhancing Sustainability in Construction: Investigating the Thermal Advantages of Fly Ash-Coated Expanded Polystyrene Lightweight Concrete

This study investigates a sustainable coating method for modified expanded polystyrene (MEPS) beads to improve the thermal insulation of lightweight concrete intended for wall application. The method employed in this study is based on a novel coating technique that represents a significant advancement in modifying Expanded Polystyrene (EPS) beads for enhanced lightweight concrete. This study experimentally assessed the energy-saving capabilities of MEPS concrete in comparison to control groups of uncoated EPS beads and normal concrete by analysing early-stage temperature, thermal conductivity, specific heat capacity, heat flux, and thermal diffusivity. The thermal conductivity of MEPS concrete is approximately 40% lower than that of normal concrete, demonstrating its usefulness in enhancing insulation. The heat flux calculated for MEPS concrete is significantly reduced (approximately 35%), and it has a 20% lower specific heat capacity than ordinary concrete, indicating a reduction in energy transfer through the material and, thus, potential energy-efficiency benefits. Furthermore, the study discovered that all test objects have very low thermal diffusivity values (less than 0.5 × 10−6 m2/s), indicating a slower heat transport through the material. The sustainable coating method utilized fly ash-enhanced thermal efficiency and employed recycled materials, hence decreasing the environmental impact. MEPS concrete provides a practical option for creating sustainable and comfortable buildings through the promotion of energy-efficient wall construction. Concrete incorporating coated EPS can be a viable option for constructing walls where there is a need to balance structural integrity and adequate insulation.

Comparisons of Self-Report With Objective Measurements Suggest Faster Responding but Little Change in Response Quality Over Time in Ecological Momentary Assessment Studies.

Response times (RTs) to ecological momentary assessment (EMA) items often decrease after repeated EMA administration, but whether this is accompanied by lower response quality requires investigation. We examined the relationship between EMA item RTs and EMA response quality. In one data set, declining response quality was operationalized as decreasing correspondence over time between subjective and objective measures of blood glucose taken at the same time. In a second EMA study data set, declining response quality was operationalized as decreasing correspondence between subjective ratings of memory test performance and objective memory test scores. We assumed that measurement error in the objective measures did not increase across time, meaning that decreasing correspondence across days within a person could be attributed to lower response quality. RTs to EMA items decreased across study days, while no decrements in the mean response quality were observed. Decreasing EMA item RTs across study days did not appear problematic overall.

Anxiety-, and depression-like behavior following short-term finasteride administration is associated with impaired synaptic plasticity and cognitive behavior in male rats

Finasteride, a 5α-Reductase inhibitor, is used to treat male pattern baldness and benign prostatic hyperplasia. Several clinical studies show that chronic finasteride treatment induces persistent depression, suicidal thoughts and cognitive impairment and these symptoms are persistent even after its withdrawal. Previous results from our lab showed that repeated administration of finasteride for six days induces depression-like behavior. However, whether short-term finasteride administration induces anxiety-like behavior and memory impairment and alters synaptic plasticity are not known, which formed the basis of this study. Finasteride was administered to 2–2.5 months old male Wistar rats for six days and subjected to behavioral evaluation, biochemical estimation and synaptic plasticity assessment. Anxiety-like behavior was evaluated in the elevated plus maze (EPM), open field test (OFT), light/dark test (LDT), and novelty suppressed feeding test (NSFT), and learning and memory using novel object recognition test (NORT) and novel object location test (NOLT) and depression-like behavior in the sucrose preference test (SPT). Synaptic plasticity in the hippocampal Schaffer collateral-CA1 was evaluated using slice field potential recordings. Plasma corticosterone levels were estimated using ELISA. Finasteride administration induced anxiety-like behavior in the EPM, OFT, LDT and NSFT, and depression-like behavior in the SPT. Further, finasteride induced hippocampal dependent spatial learning and memory impairment in the NOLT. In addition, finasteride decreased basal synaptic plasticity and long-term potentiation (LTP) in the hippocampus. A trend of increased plasma corticosterone levels was observed following repeated finasteride administration. These results indicate the potential role of corticosterone and synaptic plasticity in finasteride-induced effects and further studies will pave way for the development of novel neurosteroid-based therapeutics in neuropsychiatric diseases.

Design and test of an efficient seedling pick-up device with a combination of air jet ejection and mechanical action

Low degree of transplanting automation will affect production efficiency and planting quality in vegetable cultivation. A new seedling pick-up device was designed and constructed to reduce direct grasping damages to seedlings and improve transplanting efficiency. The pick-up device consists of an air jet loosening device, a flexible pick-up manipulator, a parallel feeding device, and a multi-axis motion control system. Its working principle is to use air jet ejection to assist in loosening of seedling roots from the tray cells, grasp their stems for extracting with the pick-up manipulator, and finally transfer them to the delivery device for feeding into the planting device as needed. The mechanical structure and working parameters of each component were designed, and the control system was constructed according to the working requirements of ejecting, extracting, transferring, and discharging operations. A prototype of the new pick-up device was constructed, and its performance evaluation was conducted using an orthogonal experimental design using cucumber, pepper and caluiflower as test objects. The results showed that the test object, the root lump's moisture content and the loosening way (either as a whole or individual loosening of seedlings) had significant effects on the success ratio in picking up seedlings. Overall, the success in picking up seedlings from the cell was found to be influenced by horticultural and mechanical factors. Under the optimal level group, the maximum success ratio for automatic picking up seedlings was up to 94.49% for pepper while that of cucumber and cauliflower recorded 90.75% and 92.62%, respectively. The seedling pick-up performance was satisfactory for efficient transplanting requirements.

Light environment affects the efficiency of surgical suture training

BackgroundSuture knotting is the basis of surgical skills. In the process of surgical skills learning, the surrounding environment, especially the light, will affect the efficiency of learning. This study investigated the effect of optical environment on the learning of stitching and knotting skills.MethodsA total of 44 medical students were randomly divided into four groups and participated in the study of suture knotting in four different optical environments. During the process, we assess objective pressure level by testing salivary amylase activity Likert scale and objective structured clinical examination (OSCE) was used to estimate the subjective psychological state and overall skill mastery in surgical suturing respectively.ResultsUnder high illumination conditions (700 lx), the salivary amylase activity of the high color temperature group (6000 K) was significantly higher than that of the low color temperature group (4000 K) (p < 0.0001). Similarly, under low illumination (300 lx), the salivary amylase activity of the high color temperature group was also significantly higher than that of the low color temperature group (p < 0.05). The student under high illumination conditions (700 lx) and the low color temperature (6000 K) have an autonomy score between 37–45, which is significantly higher compared to the other three groups (p < 0.0001). Group 2 has an average OSCE score of 95.09, which were significantly higher than those of the other three groups (p < 0.05).ConclusionHigh illumination combined with low color temperature is considered as the optimal training conditions, promoting trainees' optimism, reducing stress levels, and enhancing learning efficiency. These results highlight the pivotal role of light environment in improving the quality and efficiency of surgical skills training.

Experimental Study to Determine the Development of Axial Stiffness of Wood Screws with Increasing Load Cycles

123 withdrawal tests were conducted to investigate the change in axial stiffness of fully threaded screws under axial loading and up to four loading cycles. The screws were initially loaded in two cycles within the elastic range, followed by two cycles up to 90% of the characteristic load-carrying capacity. Several parameters relevant to construction practice were varied. The angle between the screw axis and the grain ranged from 30° to 90°, the timber material was varied between glued laminated timber (glulam) and laminated veneer lumber (LVL) made of beech, and the screw diameter ranged from 8 mm to 12 mm. The test results indicate that axial stiffness increases upon reloading compared to the initial loading. On average, axial stiffness increases by 11% between the first and second loading and remains at this level during unloading and further load cycles. However, if the load exceeds the linear–elastic range, the axial stiffness is reduced due to plastic deformation. A comparison with tests on the composite axial stiffness of fully threaded screws in glulam shows that even with a different test setup and testing objective, there is a slight increase in axial stiffness from the first to the second load cycle in the range of 4 to 8%.

FLEXURAL BEHAVIOR OF BAMBOO REINFORCED FERROCEMENT PANELS

Ferrocement is an emerging technology that differs from conventional reinforced concrete by the manner in which the reinforcing elements are dispersed and arranged. It consist of closely spaced, multiple layers of wire mesh embedded in cement mortar. Traditionally steel is used as reinforcement in concrete structures; but because of cost and availability, replacement of steel with some other suitable material as reinforcement is now a major concern. The construction industry is the main consumer of energy and materials in most of the countries. Since Bamboo is a natural, ecologically friendly, cheap and also readily available material; it can be use as a substitute of wire meshes in reinforcing of Ferrocement structures. This study describes the results of testing of Ferrocement beams reinforced with different number of Bamboo mesh layers and variation in spacing of bamboo reinforcement. The main objective of these experimental tests is to study the effect of using different numbers of Bamboo mesh layers and spacing variation on the Flexural strength of Ferrocement beams.

Comparison of Marshall Quotient Value on Laston Ac-Wc with Additional Pecan Shell Charcoal Waste

Some factors that affect the durability of asphalt include the type of asphalt concrete mixture used, Mixed materials must have good mechanical properties and be able to support high traffic loads. This study aims to determine the characteristics of marshalls in the addition of asphalt coated concrete wear (laston AC-WC with a percentage of hazelnut shell charcoal mixture of 0%, 2%, 3%, and 5%, and determine the effect of the quality of stiffness of the hazelnut shell charcoal waste mixture. This study used the marshall test method. The results showed that wear-coated concrete asphalt (AC-WC) with the addition of 5% hazelnut shell charcoal met the specifications, as well as a mixture of asphalt concrete with a charcoal content of 0% hazelnut shells or pure test objects. The value of VIM, and VFA is not a percentage of 0%, 2%, 3%, and 5% that meet the predetermined specification so that the difference in pure Ac-Wc laston and Ac-Wc laston with coconut shell charcoal additives, can be proven by the Marshall quotient value in the absence of a mixture with an average Marshall Quotient value of 590.13 Kg, in a mixture of 2% with an average Marshall Quotient value of 1004.91 Kg, on a mixture of 3% with an average value of 1024.99 Kg, and on a mixture of 4% with an average value of Marshall Quotient of 681.93 Kg. Thus, it can contribute to the development of road construction technology and become a reference in the use of hazelnut shell charcoal in wear-coated concrete asphalt mixture (AC-WC) as an alternative to environmentally friendly and sustainable mixed materials