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Influences of Inclined Pre-Existing Flaw on Shale Failure Modes in Uniaxial Compression Tests

Numerous studies have focused on the mechanical properties of shale specimens to support hydraulic fracturing in shale gas engineering. However, the failure modes of shale specimens containing a pre-existing flaw are still not clear. A series of uniaxial compression tests were conducted on shale specimens containing a pre-existing flaw coupled with acoustic emission (AE) technology and a high-speed camera. A slow enough and variable loading speed scheme (0–50 kN: 0.1 kN/s, 50–100 kN: 0.05 kN/s; 100-failure: 0.02 kN/s) is adopted to allow microcracks to fully develop. The damage mechanism in the mesoscale from moment tensor inversion of the AE signals and the cracking behaviors on the macroscale were associated. Both the pre-existing flaw and the bedding layers had significant influences on the mechanical characteristics, progressive cracking, and failure modes of the shale specimens. The peak stress increases fluctuated as the bedding layer angle α increases, and the maximum and minimum values take place at α=90° and α=0°, respectively. In addition, the pre-existing flaw, the bedding layers, and the compression stress field jointly control the failure modes of the shale specimens. It was found that the α=0° specimen failed due to tension splitting, the α=30° specimen failed due to tension splitting and shear across the matrix, the α=60 specimen failed due to shear across the shale matrix and shear along the bedding layers, and the α=90° specimen failed due to tension along the bedding layers and shear across the shale matrix. The study can provide some references to the construction of complex crack networks in shale gas engineering.

Push-and-release tests of a steel building with hybrid base isolation

Experimental testing of a two-storey 5875 square meters steel braced-frame structure resting on a reinforced concrete slab isolated from the foundations through a hybrid system (28 high-damping rubber bearings and 36 low-friction sliding bearings) is presented. The building incorporates a push-and-release device to evaluate its actual global dynamic response up to displacement amplitudes induced by extreme seismic events, allowing test repetitions during its service life. The testing set up and the experimental campaign, consisting of quasi-static push tests (slow loading and unloading) and push-and-release dynamic tests (slow loading and subsequent sudden release), are described. The experimental results have peculiarities related to the building (structural typology and size, foundation geometry on a steep slope, presence of the push-and-release device for future additional tests), the magnitude of the maximum horizontal displacement never achieved before (285 mm and 227 mm in the quasi-static and dynamic tests, respectively), the global and local monitored parameters (horizontal and vertical displacements, strains, accelerations, in addition to environmental conditions) providing a comprehensive insight into the behaviour of the hybrid isolation system and superstructure.

The Effect Of Chronotype On The Dose-Response To Field-Based Training In Elite Rugby League

Rugby League (RL) seasons are often congested, with matches often being played within the afternoon and evening hours. Despite this, training commonly occurs within the morning hours. To our knowledge, the impact of the start time of training and the impact of chronotype is yet to be examined in a RL context. PURPOSE: to examine the effect of chronotype and circadian variation on the dose-response to field-based training in elite RL. METHODS: 22 male RL players from a single National Rugby League club volunteered to participate in the study. Their chronotype was categorised by a newly validated index, the Athlete Specific Chronotype Index (ACTi). Training start time was categorised as morning (before midday), afternoon (12:00 to 18:00 h) or evening (after 18:00 h). Physical performance was recorded during 47 pre-season and 67 in-season main training sessions, using GPS units sampling at 10 Hz (Optimeye S5, Catapult Interventions, Scorsby, Australia). Performance metrics included relative distance covered (m·min-1), relative high speed running distance (HSR (m·min-1); > 14.4 km·h-1), PlayerLoad 2D (arbitrary units; AU) PlayerLoad slow (AU) and acceleration load (AU). Perceptual measures included self-reported wellness (sleep quality and readiness to train) and session ratings of perceived exhaustion (sRPE). RESULTS: 11 players were categorised as morning types, 10 as intermediate types and one as an evening type. There was no influence of chronotype on pre-training wellness measures (p = 0.35 - 0.75). Start time of main training sessions influenced readiness (p = 0.002) and sleep quality (p < 0.001) with a 0.20 AU increase in readiness and a 0.57 AU increase in sleep quality between 07:00 and 19:00 h. No influence of chronotype was found on the sRPE response to external load (p = 0.12 - 0.63). The start time of main training sessions affected the sRPE response to PlayerLoad slow (p = 0.004) and acceleration load (p = 0.01). Post-hoc analysis revealed a lower sRPE response to PlayerLoad slow and acceleration load within the evening training sessions compared to morning and afternoons. CONCLUSION: The majority of athletes were categorised as earlier chronotypes, however they showed improved wellness prior to evening sessions and reduced sRPE responses to accelerometer and locomotor based metrics within these sessions.

Design of a big data integration system for physical fitness training development based on speech recognition technology

Physical fitness training development research needs a large amount of data support, and the current data integration system uses the global view to extract data sequentially, which has the problems of too slow loading data and low query efficiency. Design a big data integration system for physical fitness training development based on speech recognition technology. Using FPGA as the carrier, design the speech recognition control module, storage communication module and speech input judgment module. Based on the hardware part of the system, the recognition signal is processed using speech recognition technology. By establishing global ontology mapping relationship, the integration of big data of physical training development is realized. The system functional test results show that the designed system has its minimum query efficiency improved by about 52.6%, and has higher loading efficiency and better processing capability..

Tensile and Charpy impact properties of heat-treated high manganese steel at cryogenic temperatures

The structural materials for the superconductor in next generation DEMO fusion reactor are in great demanded with excellent nonmagnetic and mechanical properties such as strength, toughness, and ductility at the cryogenic temperature. High-Mn steels, newly developed for application to cryogenic industry, including DEMO fusion reactor, can change its deformation mechanism by twinning, martensite transformation and dislocation slip according to the range of stacking fault energy (SFE). Therefore, it is very important to investigate the mechanism of deformation behavior at cryogenic temperatures. In this study, tensile tests and Charpy impact tests were performed to investigate the effects of heat treatment on mechanical properties of high-Mn steels at cryogenic temperatures. In addition, the deformation mechanism of high-Mn steels at room temperature and cryogenic temperature was investigated through various analysis such as microstructure, XRD, EBSD and TEM. As a result, phase transformation from austenite to ε and α'-martensite was generated in the tensile test with a slow loading rate at cryogenic temperatures, while ε and α'-martensite was not observed in the Charpy impact test with a high loading rate.

Development of Intelligent Controlled Microgrid for Power Sharing and Load Shedding

An online trained intelligent voltage controller is developed in this article to improve the transient responses of the voltage and frequency of an islanded microgrid with droop control and achieve fast load shedding. Although the droop control algorithm has been extensively adopted in microgrid, some shortcoming of the droop control, such as poor disturbance rejection and slow transient response, seriously affect the power quality and stability in islanded microgrid. Moreover, when the power consumption of the demand exceeds the generated power of the distributed generators in microgrid, the decreased frequency will lead to the microgrid blackout owing to the slow load shedding characteristics of the droop control. Hence, in this article, an online trained Petri probabilistic wavelet fuzzy neural network (PPWFNN) controller is developed as the voltage controller to replace the traditional proportional--integral controller in a battery energy storage system for an islanded microgrid with droop control to achieve fast load shedding. The network structure and the online learning algorithm of the proposed PPWFNN are detailedly introduced. Finally, some experimental results are provided to validate the effectiveness of the microgrid using the proposed PPWFNN controller for the improvements of the power sharing and load shedding.

Rancang Bangun Sistem Informasi Profil TK Al Hidayah Kebumen dengan Metode Waterfall Berbasis Website

Al Hidayah Kindergarten does not yet have an information system that can be accessed through the website so the presentation of information is still done conventionally. This study aims to build a website-based school profile information system. This information system can be used by schools to improve the quality of information services to the community. The method used in this research is the waterfall model system development method because this method is the most suitable development model used by developers, system project work is easy to control and can be timely. The programming language that the author uses is PHP (Hypertext Preprocessor) and uses a MySQL database. Testing the feasibility of the system using blackbox testing. The functions tested are admin and user pages. The test results on the admin page obtained that 90% were declared successful, 10% were declared slow loading, and no failed test items were found. While on the user page 95% was declared successful, 5% was declared slow loading, and no failed test items were found. Keywords: information system, website, waterfall model, PHP, blackbox testing

Analysis of Slow Coal Loading in MV. Placid Sea at Tabone Anchorage

&#x0D; &#x0D; &#x0D; PT. Indo Dharma Transport Banjarmasin is located in South Kalimantan and is one of Indonesia's best ship agency companies. This research aims to determine the factors that cause the slow process of transferring or loading coal from barges to large ships on MV. Placid Sea in Taboneo Anchorage, Banjarmasin, and to find out how to minimize the loading time of coal from barges to large ships. This research was conducted at PT. Indo Dharma Transport Banjarmasin. This type of qualitative descriptive research is the result of research in the form of data not stated in numbers but presented in the form of a narrative. The results showed the slow process of transferrin or loading coal from barges to large ships on MV. The Placid Sea in Taboneo Anchorage was due to several factors that hindered the loading process, including damage to the loading and unloading equipment, bad weather, and the slow process of barging berthing. Therefore, periodic maintenance and checks on loading and unloading equipment are needed to avoid damage during the loading process and assist tug boats in barging and berthing.&#x0D; &#x0D; &#x0D;

Data Orchestration for Accelerating GPU-Based Light Field Rendering Aiming at a Wide Virtual Space

Recently, research on six-degree-of-freedom virtual reality (VR) systems based on a light field (LF) has been actively conducted. The LF-based approach is photorealistic and less prone to errors than the existing three-dimensional (3D) modeling-based approach. On the other hand, because the amount of data is very large for LF-based immersive virtual reality, it is important to manage the data efficiently. This paper makes two major contributions to data management for rendering acceleration in this context. First, the GPUs commonly used for high-speed rendering require optimization of the data transfer process between the host memory and the device memory. This paper proposes a simple but effective way to maximize data reuse by finding the proper size of a transfer unit depending on the target applications and the system capability constraints. Also, view synthesis and data transfer are performed in a pipelined manner to hide the data movement time. Second, for the LF rendering of a wide space, data management in the storage-host-GPU hierarchy is attempted for the first time. As the size of the virtual space increases, the required amount of LF data grows rapidly and exceeds the allocatable host memory capacity. Because the loading of data stored in storage is a very slow process, a system-level LF rendering structure that carefully considers the characteristics of the storage-host-GPU memory hierarchy should be designed. In this paper, progressive LF updating is proposed, and it prevents rendering stalls caused by slow storage data loading. Experimental results show that a 360-degree view with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9000 \times 2048$ </tex-math></inline-formula> resolution can be rendered in an average of 2.57 ms from LF data with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4096 \times 2048$ </tex-math></inline-formula> resolution, achieving performance close to 400 frames per second.

Web Traffic Time Series Forecasting Using ARIMA Model

Abstract: Web traffic prediction is a major concern since it has the potential to produce severe snags in the working of websites. It is one of the most difficult tasks to make predictions about future time series values, so been a hot topic for research. The increase in web traffic may encounter a crashed site or very slow loading time. Such disturbances may cause many disturbances for the users, consequently decreased users rating of the site and user move to another site that affects the business. We have implemented a forecasting model to predict web traffic. ARIMA model is used for Web traffic time series forecasting. We have used some of the features like page name, date visited, and the number of visits for prediction with higher accuracy. Keywords: Web traffic prediction, ARIMA model, Time series forecasting, Data Collection and Feature Understanding.

Modeling and Analysis of Voltage Ripple-Controlled SIDO Buck Converter in Pseudo-Continuous Conduction Mode with Limited Cross-Regulation and Fast Load Transient Performance

Typical voltage mode-controlled DC–DC converters with single-inductor dual-output (SIDO) in pseudo-continuous conduction mode (PCCM) have slow load transient performance, and cross-regulation still exists between their two outputs. For the purposes of suppressing the cross-regulation and improving the load transient performance, a voltage ripple control technique for a PCCM SIDO buck converter is proposed in this study. A description of the PCCM SIDO buck converter and the voltage ripple control technique is provided in detail. In addition, the small-signal model was established, and the cross-regulation was further compared by Bode plots, as well as the load range and the power losses being analyzed. The cross-regulation and load transient performance of the voltage ripple-controlled PCCM SIDO buck converter was studied and compared with the conventional voltage mode-controlled. Using the proposed voltage ripple control for PCCM SIDO buck converters, we found no cross-regulation or rapid load transient behavior, which was validated by experimental results.

Control strategy of load following for ocean thermal energy conversion

Ocean thermal energy conversion (OTEC) provides a feasible solution for sustainable and stable power supply in remote islands. In this paper, a thermodynamic model of the OTEC system is developed to study the dynamic response of power output and superheating degree to manipulated variables. Afterward, a control strategy of load following for the island OTEC system is proposed. Finally, two controllers, MPC and PI, are designed and compared under fast and slow load changes as well as disturbance rejection test. The results indicate that the power output of OTEC system is sensitive to the speed of working-fluid pump, reaching the adjustment range of 14.7 kW when the nominal speed decreases by 30%. In addition, model predictive control (MPC) shows better performance in both rapid and slow load-change modes. Especially, in the rapid load-change mode, the MPC controller could always keep the evaporator outlet superheating in the range of 2–4.5 °C, while the PI controller may introduce no superheat that may cause liquid impact. Both MPC and PI controller can stabilize the power output at the set point under one day's measured disturbance, while MPC controller makes the superheating degree of evaporator outlet within smaller temperature fluctuations (<0.2 °C).

Dynamic effect in the fatigue fracture of viscoelastic solids

Crack growth in viscoelastic solids under cyclic loading tends to be faster than that under static loading with the same amplitude. This phenomenon, known as “dynamic effect”, is a key mechanism underlying the fatigue fracture of soft viscoelastic polymers, but its physical nature remains a mystery. We develop a scaling theory to delineate how viscoelastic dissipation associated with crack growth is governed by the coupling between three time-dependent processes: cyclic loading, crack growth and viscoelastic creep. In the limit of slow crack growth and slow cyclic loading, a simple integral equation is derived to predict the crack growth velocity under different cyclic loading frequencies.

Biomechanical analysis of the drilling parameters for early osteonecrosis of the femoral head

Background and objectiveCore decompression is a surgical procedure commonly used to treat the early osteonecrosis of the femoral head. However, It is not known whether different drilling parameters affect postoperative biomechanical strength. This study aimed to analyze the mechanical stability of different drilling locations and diameters of core decompression using finite element analysis. MethodsFinite element models were established based on computed tomography images obtained from five healthy participants, including the different drilling locations (Lesser trochanter: Above, Parallel, and Below) and diameters. Biomechanical parameters including stiffness and stress were evaluated under slow running loads. ResultsAt the same drilling diameter, the femoral stiffness was highest (p < 0.05) in the Above group and lowest in the Below group, while the maximum equivalent stress of the entry area and the necrotic area was highest (p < 0.05) in the Below group and lowest in the Above group. With the increase of drilling diameters, the stiffness decreased and its decreased percentage comparing the preoperative: Above (1.06–8.82%), Parallel (2.51–13.61%), and Below (3.99–15.06%). The maximum equivalent stress of the entry area and necrotic area increased as the drilling diameter increased, and its increased percentage comparing the preoperative, for the entry area: Above (14.11–219.58%), Parallel (35.91–306.37%), and Below (46.12–240.98%); for the necrotic area: Above (13.64–114.69%), Parallel (29.37–187.76%), and Below (44.76–202.10%). The range of safety drilling parameters (SDP) was obtained (Below<9 mm, Parallel<11 mm, and Above<13 mm) by comparing the maximum equivalent stress of two areas and its yield strength. For patients of different sizes and normal bone mineral density (BMD), the maximum equivalent stress of the two areas did not exceed its yield strength using the range of SDP, except for the patients with abnormal BMD (Osteoporosis) or high body mass index (BMI≥28 kg/m2). ConclusionsThe biomechanical properties of early osteonecrosis of the femoral head deceased with increasing drilling diameters parameters, especially at the location below the lesser trochanter. The SDP (Below<9 mm, Parallel<11 mm, and Above<13 mm) is a suitable reference for most patients to perform slow running postoperatively, while it may be not suitable for patients with osteoporosis or obesity.

Analysis of Masticatory Muscle Tendon-aponeurosis Hyperplasia by Using Next-generation Sequencing.

Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a disease associated with a mouth opening limitation. Here, we conducted a bioinformatics analysis to examine gene expression patterns in patients with MMTAH in comparison to those with facial deformity (FD). Seven MMTAH patients and three FD patients were recruited. We conducted RNA sequencing analysis, quantitative reverse transcription polymerase chain reaction and immunoblot analysis. Of the identified 19,767 mapped read tags that showed clear differential expression, 2,471 genes were significantly up-regulated and 2,849 genes were significantly down-regulated in patients with MMTAH compared to those in patients with FD. Among the up-regulated genes, ten genes were significantly increased. The distribution of up-regulated and down-regulated genes at different ages tended to be similar. Moreover, the protein levels of Ankyrin Repeat Domain 2, Troponin T1 and myosin heavy chain 7, which are associated with slow twitch fibers and mechanical loading, were strongly expressed in patients with MMTAH compared to those in patients with FD. The gene expression pattern in MMTAH patients was similar regardless of age. As the transition of fast-to-slow twitch in the skeletal muscle is induced by mechanical loading, and up-regulation of slow twitch molecules was observed in MMTAH patients, mechanical loading is suggested to be implicated in MMTAH.

Impact Assessment and Mitigation Techniques for High Penetration Levels of Renewable Energy Sources in Distribution Networks: Voltage-control Perspective

The integration of renewable distributed generation (RDG) into distribution networks is promising and increasing nowadays. However, high penetration levels of distributed generation (DG) are often limited as they may have an adverse effect on the operation of distribution networks. One of the operation challenges is the interaction between DG and voltage-control equipment, e. g., an under-load tap changer (ULTC), which is basically designed to compensate for voltage changes caused by slow load variations. The integration of variable DGs leads to rapid voltage fluctuations, which can negatively affect the tap operation of ULTC. This paper investigates the impact of high penetration levels of RDG on the tap operation of ULTC in distribution networks through simulations. Various mitigation techniques that can alleviate this impact are also examined. Among these techniques, constant power-factor mode is regarded as the best trade-off between the simplicity and effectiveness of minimizing the number of tap operations. Simulations are performed on a Canadian benchmark rural distribution feeder using OpenDSS software.

Modeling of rubber-cord layers under quasi-static loading

Modeling a pneumatic tire with a strong change in shape causes the problem of choosing an adequate model for rubber-cord plies. Generally, the classical method of asymptotic homogenization is not suitable due to physical and geometrical nonlinearity for the strain up to 15 %. The known models used for simulation the entire tire as well as rubber-cord plies are analyzed. A choice is made in favor of modeling the plies using the stress anisotropic potential, which is an anisotropic function of the strain tensor invariants. The relationship of such a constitutive law with a quasi-linear constitutive equation in terms of stress and strain differentials is indicated. A convenience of these two types of constitutive equations in terms of numerical implementation is also given. A modification of the effective properties definition for an inhomogeneous layer is explained. The difference from the standard effective moduli definition is clarified. The arrangement of the cords is supposed to be approximately periodic and all cords to be equivalent to the effective fiber. Two models of a rubber-cord plies are described under such assumption. These are a model of an orthotropic material and a model of a transversely isotropic material. Computational experiments, which make it possible to determine the material parameters of anisotropic potentials, are pointed out. Real tests with a sample of rubber ply under slow quasi-static loading were conducted. Significant hysteresis was detected. It is shown that an additive model combining a hyper elastic material with Maxwell viscoelastic model provides good accuracy in stress dependence on the strain rate. The numerical procedure developed to calculate solution to the quasi-static problem of tire deformation is described. It is implemented in home-made computer code. A numerical example on the tire simulation is given. That is so-called breaking test, in which strong deformation is achieved and the developed model is applied to.

Influence of the Hydrophilic Surface of Nanofiber Support on the Performance of Hybrid Supercapacitors

Concerns associated with global warming and the depleting reserves of fossil fuels have highlighted the importance of high−performance energy storage systems (ESSs) for efficient energy usage. ESSs such as supercapacitors can contribute to improved power quality of an energy generation system, which is characterized by a slow load response. Composite materials are primarily used as supercapacitor electrodes because they can compensate for the disadvantages of carbon or metal oxide electrode materials. In this study, a composite of oxide nanoparticles loaded on a carbon nanofiber support was used as an electrode material for a hybrid supercapacitor. The addition of a small amount of hydrophilic FeN@GnP (Fe− and N−doped graphene nanoplates) modified the surface properties of carbon nanofibers prepared by electrospinning. Accordingly, the effects of the hydrophobic/hydrophilic surface properties of the nanofiber support on the morphology of Co3O4 nanoparticles loaded on the nanofiber, as well as the performance of the supercapacitor, were systematically investigated.

А New Theatre Experience: Page Experience Signals

In the digital age struggling with the pandemic, theatres strive to gain new and retain old audiences by providing user experiences online. Information about events, electronic ticket purchasing, and live streaming require improved website functionality, where Page Experience Signals, the latest practice recommended by Google, have been gaining importance. As part of this research, five experiential signals were analyzed on a sample consisting of 18 Belgrade theatres’ homepages: Core Web Vitals, Mobile-friendliness, Safe browsing, Secure connection, and the absence of intrusive interstitials. All analyzed websites were found to provide safe internet search and generally did not contain disruptive content on their homepages. Given that an increasing number of visitors are using mobile devices to search for and purchase tickets, several theatres should pay attention to the need to optimize their website for mobile visits, and to secure the data transfer protocol. In addition, common weaknesses in the theatres’ Page Experience Signals were highlighted – the slow homepage loading performance and achieving their visual stability; the webmasters were also given proposals on overcoming them during the transition period after the algorithm change. The recommendation for future research is to assess at the end of 2021 whether the Page Experience Signals of the Belgrade theatres have contributed positively or negatively to their organic search performance on Google.&#x0D; Article received: June 3, 2021; Article accepted: June 23, 2021; Published online: October 15; Original scholarly article&#x0D; How to cite this article: Krstić, Nataša. "А New Theatre Experience: Page Experience Signals." AM Journal of Art and Media Studies 26 (October 2021): 129-141. doi: 10.25038/am.v0i26.476

Study on Tuned Mass Damper Use in High-Rise Building

Abstract: Current styles in the construction industry demand tall and light buildings, which are also flexible and low-cost. This increases the chances of failure and problems from the point of view of usability. Many modern methods are available to reduce structural vibration, with many vibration control strategies, the idea of using the new TMD. This study was conducted to study the efficacy of using TMD in controlling structural movement. Initially a numerical algorithm was developed to investigate the response of a shear structure containing TMD. Next another numerical algorithm was developed to investigate the response of an independent 2D model programmed with TMD. Three slow loading methods used. The first was a sinusoidal upload, the second was in line with the corresponding timeline according to IS-1894 (Part -1): 2002 with 5% erosion (PGA = 1g) and the third was 1940 El Centro Earthquake Record (PGA) = 0.313g). From research it has been found that TMD can be used effectively to control building vibrations. TMD worked best when the softness of the structure was low. Gradually increase the magnitude of the effects of TMD on the gradual decline in the response to structural migration. Keywords: Harmonic absorber, viscous damper, crankshaft torsional damper, kinetic energy,