scholarly journals Numerical calculation and study of differential equations of muscle movement velocity based on martial articulation body ligament tension

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zan Liu ◽  
Huiying Shao ◽  
Dimah Alahmadi ◽  
Mohammed Yousuf Abo Keir
Keyword(s):  
Differential Equation ◽  
Kinetic Method ◽  
Calculation Model ◽  
Movement Velocity ◽  
Initial Tension ◽  
Initial Stage ◽  
Impact Peak ◽  
Ligament Tension ◽  
Continuous Use ◽  
The Impact

Abstract The paper analyses the impact of ligament stretch and tension on the speed of movement in martial arts from the perspective of sports physiology. It establishes the numerical relationship between the peak impact value of the ligament speed and the differential equation of the flexibility of the joints in the initial stage of tension (impact peak). It was found that the differential equation of the ligament tension of the movement is formed after the movement is stable, which cannot reflect the flexibility of the ligament and the mastery of the movement. In this paper, a tension calculation model for ligament equilibrium is established by using a kinetic method of motion. Although it is a static equation, continuous use can obtain dynamic effects. The simulation proves that the initial tension change is more realistic.

scholarly journals Understanding continued smartwatch usage: the role of emotional as well as health and fitness factors

2021 ◽  
Author(s):  
Carolin Siepmann ◽  
Pascal Kowalczuk
Keyword(s):  
Structural Equation ◽  
Goal Pursuit ◽  
Perceived Usefulness ◽  
Equation Modeling ◽  
Emotional Factors ◽  
Health And Fitness ◽  
Important Barrier ◽  
Personal Fitness ◽  
Continuous Use ◽  
The Impact

AbstractSmartwatches are the most popular wearable device and increasingly subject to empirical research. In recent years, the focus has shifted from revealing determinants of smartwatch adoption to understanding factors that cause long-term usage. Despite their importance for personal fitness, health monitoring, and for achieving health and fitness goals, extant research on the continuous use intention of smartwatches mostly disregards health and fitness factors. Grounding on self-determination theory, this study addresses this gap and investigates the impact of health and fitness as well as positive and negative emotional factors encouraging or impeding consumers to continuously use smartwatches. We build upon the expectation-confirmation model (ECM) and extend it with emotional (device annoyance and enjoyment) as well as health and fitness factors (goal pursuit motivation and self-quantification behavior). We use structural equation modeling to validate our model based on 335 responses from actual smartwatch users. Results prove the applicability of the ECM to the smartwatch context and highlight the importance of self-quantification as a focal construct for explaining goal pursuit motivation, perceived usefulness, confirmation and device annoyance. Further, we identify device annoyance as an important barrier to continuous smartwatch use. Based on our results, we finally derive implications for researchers and practitioners alike.

scholarly journals Monitoring of the Impact of Lithium Nitrate on the Alkali–aggregate Reaction Using Acoustic Emission Methods

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Justyna Zapała-Sławeta ◽  
Grzegorz Świt
Keyword(s):  
Acoustic Emission ◽  
Initial Reaction ◽  
Lithium Nitrate ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Acoustic Activity ◽  
Initial Stage ◽  
Chemical Admixture ◽  
Different Characteristics ◽  
The Impact

The study analyzed the possibility of using the acoustic emission method to analyse the reaction of alkali with aggregate in the presence of lithium nitrate. Lithium nitrate is a chemical admixture used to reduce adverse effects of corrosion. The tests were carried out using mortars with reactive opal aggregate, stored under the conditions defined by ASTM C227. The acoustic activity of mortars with a corrosion inhibitor was referred to linear changes and microstructure of specimens in the initial reaction stages. The study found a low acoustic activity of mortars with lithium nitrate. Analysis of characteristic parameters of acoustic emission signals, combined with the observation of changes in the microstructure, made it possible to describe the corrosion processes. As the reaction progressed, signals with different characteristics were recorded, indicating aggregate cracking at the initial stage of the reaction, followed by cracking of the cement paste. The results, which were referred to the acoustic activity of reference mortars, confirmed that the reaction of opal aggregate with alkali was mitigated in mortars with lithium nitrate, and the applied acoustic emission method enabled the detection and monitoring of ASR progress.

Grinding Force Model for Low-Speed Grinding Based on Impact Principle

2013 ◽  
Vol 797 ◽  
pp. 123-128
Author(s):  
Ming He Liu ◽  
Xiu Ming Zhang ◽  
Shi Chao Xiu
Keyword(s):  
Sliding Friction ◽  
Impact Load ◽  
Grinding Force ◽  
Calculation Model ◽  
Force Model ◽  
Grinding Process ◽  
Low Speed ◽  
Impact Area ◽  
Force Mechanism ◽  
The Impact

In the low-speed grinding process, the force generated when the wheel grinding the workpiece is the result of sliding friction, plough and cutting. While in the actual study, the cutting process has attracted extensive attention. Impact effect to the entire grinding process on the contact is ignored so that the error exists between the calculation grinding force and the measured grinding force. Basing on the shock effect to the grinding process, the paper divides the contact area into impact area and cutting area. And the model of impact load generated from single grit is built. Moreover, the grinding force theoretical calculation model and total grinding force mathematical model is also constructed by analyzing the impact load affecting on the grinding force mechanism. Finally experimental study verifies the correctness of theoretical analysis.

Research on the hydrographic survey cycle for updating navigational charts

2021 ◽  
pp. 1-13
Author(s):  
Jing Duan ◽  
Xiaoxia Wan ◽  
Jianan Luo
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Calculation Model ◽  
Impact Factors ◽  
Factors Affecting ◽  
Material Resources ◽  
Hydrographic Survey ◽  
Survey Planning ◽  
The Impact ◽  
The Relationship

Abstract Due to the vast ocean area and limited human and material resources, hydrographic survey must be carried out in a selective and well-planned way. Therefore, scientific planning of hydrographic surveys to ensure the effectiveness of navigational charts has become an urgent issue to be addressed by the hydrographic office of each coastal state. In this study, a reasonable calculation model of hydrographic survey cycle is established, which can be used to make the plan of navigational chart updating. The paper takes 493 navigational charts of Chinese coastal ports and fairways as the research object, analyses the fundamental factors affecting the hydrographic survey cycle and gives them weights, proposes to use the BP neural network to construct the relationship between the cycle and the impact factors, and finally establishes a calculation model of the hydrographic survey cycle. It has been verified that the calculation cycle of the model is effective, and it can provide reference for hydrographic survey planning and chart updating, as well as suggestions for navigation safety.

Evaluation of a calculation model to estimate the impact of the COVID-19 pandemic lockdown on visual acuity in neovascular AMD

2021 ◽  
pp. 112067212110523
Author(s):  
Martin Stattin ◽  
Anna-Maria Haas ◽  
Daniel Ahmed ◽  
Alexandra Graf ◽  
Katharina Krepler ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Real Life ◽  
Treatment Interruption ◽  
Term Treatment ◽  
Calculation Model ◽  
Life Outcomes ◽  
Short Term ◽  
Short Term Treatment ◽  
The Real ◽  
The Impact

Purpose A model was calculated during the first Austrian coronavirus disease-2019 (COVID-19) pandemic lockdown to estimate the effect of a short-term treatment interruption due to healthcare restrictions on visual acuity (VA) in neovascular age-related macular degeneration (nAMD). The model was compared to the real-life outcomes before treatment re-started. Methods Retrospective data-collection of 142 eyes in 142 patients receiving repeated intravitreal injections with anti-VEGF at a retina unit in Vienna in a personalized pro-re-nata regimen prior to the COVID-19 associated lockdown, when treatment was deferred between March 16 and May 4, 2020. During the lockdown, the preliminary data was integrated into pre-existing formulae based on the natural course of the disease in untreated eyes in the long term. Patients were re-scheduled and treated after gradually opening operating rooms. The calculation model was compared to the effective VA change. Results The model calculated an overall VA loss of 3.5 ± 0.8 letters early treatment diabetes retinopathy study (ETDRS) ( p < 0.001 [95% CI:3.3;3.6]) on average compared to 2.5 ± 6 letters ETDRS ( p < 0.001 [95% CI:1.5;3.5]) as measured with a mean treatment delay of 61 ± 14 days after previously scheduled appointments. The total difference between the model exercise and the real-life outcomes accounted for 1 ± 5.9 letters ETDRS ( p = 0.051 [95% CI: 0.1;1.9]). Conclusion The herein presented calculation model might not be suitable to estimate the effective VA loss correctly over time, although untreated eyes and eyes under therapy show similarities after short-term treatment interruption. However, this study demonstrated the potentially negative impact of the COVID-19 pandemic lockdown on patients compromised by nAMD.

scholarly journals The Influence of the Track Parameters on Vibration Characteristics of Subway Tunnel

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Wenbo Shi ◽  
Linchang Miao ◽  
Junhui Luo ◽  
Honglei Zhang
Keyword(s):  
Soft Soil ◽  
Power Level ◽  
Coupling Model ◽  
Calculation Model ◽  
Vertical Acceleration ◽  
Subway Tunnel ◽  
Ballastless Track ◽  
Train Operation ◽  
The Impact ◽  
Wheel Track

In soft soil areas, such as the Nanjing, it is very important to quantitatively analyze the dynamic behaviors of soft soils during the metro train operation. A nonlinear coupling model of wheel-track and a finite element calculation model of tunnel and soil were established based on the mechanical character of elastic supporting block ballastless track and the actual parameters of Nanjing soft soil. The time-variant vertical acceleration of the rail, the sleepers, and the surface of the tunnel can be calculated by the models, and the frequency dependence acceleration was verified by the fast Fourier transform algorithm. A modified vibration power level for human sensitivity was used to quantify the vibration energy of each part of the system, and the impact of the parameters in the model was evaluated. The results can be applied to the metro design and construction, which also can be the guidance during the tunnel construction.

scholarly journals Atypical start-up experiments on pump as turbine

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110627
Author(s):  
Yu-Liang Zhang ◽  
Yan-Juan Zhao
Keyword(s):  
Static Pressure ◽  
Power Coefficient ◽  
Transient Performance ◽  
Test Rig ◽  
Transient Characteristics ◽  
Maximum Value ◽  
Start Up ◽  
Initial Stage ◽  
Evolution Characteristics ◽  
The Impact

At present, research on the characteristics of pumps as turbine (PATs) during the start-up process is still insufficient. To reveal the transient characteristics of a centrifugal PAT during the atypical start-up process, a test rig for the transient performance of the PAT was built; in addition, experiments on the transient hydraulic performance of three kinds of steady speed and three kinds of steady flow were conducted. Through these experiments, the evolution characteristics of the transient performance parameters of the PAT during the atypical start-up process were analyzed over time. Moreover, three dimensionless coefficients were employed to deeply reveal the transient characteristics of the PAT during atypical start-up. Results showed that the rise curves of flow rate and outlet static pressure exhibited shock phenomena. With the increase in the stable running speed after start-up, the impact phenomenon of the outlet static pressure presented a delayed trend. The dimensionless head and flow coefficients reached the maximum value at the initial stage of the atypical start-up process and then rapidly dropped to the minimum value before slowly rising to the final stable value. The dimensionless power coefficient had a maximum value at the initial stage of atypical start-up and then rapidly dropped to the final stable value.

scholarly journals Impact Size and Determinants of Indirect Cost of Financial Distress: Role of Receivable and Inventory Management

2020 ◽  
Vol 16 (2) ◽  
pp. 179-207
Author(s):  
Umar Farooq ◽  
Muhammad Ali Jibran Qamar ◽  
Krishna Reddy
Keyword(s):  
Indirect Cost ◽  
Inventory Management ◽  
Financial Distress ◽  
Multi Stage ◽  
Initial Stage ◽  
Non Linear ◽  
Management Policies ◽  
Internal Operations ◽  
The Impact

This research investigates the opportunity cost as an indirect cost of financial distress from two perspectives. First, indirect cost is estimated using multi-stage financial distress and non-linear proxy of debt. Second, receivable and inventory management are studied as determinants of indirect cost. The sample includes ongoing Pakistani firms that were healthy in the previous year and documenting positive gross profit. Results showed that firms bear opportunity loss primarily due to leverage rather than multistage financial distress. However, a non-linear relationship is found between leverage and indirect cost. Results further explored the impact of multistage financial distress on internal operations, i.e., working capital policies. It is found that firms manage receivable and inventory simultaneously during the multistage financial distress. Results revealed that increasing receivables and decreasing inventory is suitable during the transition of healthy firms to initial stage of financial distress, i.e., profit reduction. However, decreasing receivables, along with holding more inventory, is recommended for healthy firms that face liquidity problems subsequently. It is concluded that managers can reduce the indirect cost after deploying the optimal debt ratio and recommended receivable and inventory management policies.

Rock Movement in Tectonic Zones. Mining Activities and Rock Pressure Management in the Norilsk-Kharaelakh Fault Area

2020 ◽  
pp. 148-151
Author(s):  
S.G. Kirillov ◽  
Z.G. Ufatova ◽  
I.F. Khrushchev ◽  
K.A. Bashirov
Keyword(s):  
Rock Mass ◽  
High Mobility ◽  
Mining Operations ◽  
Profile Line ◽  
Initial Stage ◽  
Tectonic Zones ◽  
Rock Movement ◽  
Hazard Level ◽  
And Control ◽  
The Impact

The article describes the rock mass state within the boundaries of the Skalistiy mining allotment. The ore mass within the mine field was found to preserve its rock-bump hazard and show high mobility in the impact zone of the Norilsk-Kharaelakh Fault and the associated high failure potential manifested as roof cavings. Based on the monitoring results along underground profile lines, it was concluded that the displacement process is currently at its initial stage. Moreover, the maximum subsidence in the central part of the profile line is about 3 times higher (up to 35 mm) than in other areas. This is caused by immediate proximity of this zone to the Norilsk-Kharaelakh Fault. Assessment of the bump hazard level of this rock mass with the help of the Prognoz-2 instrument that was performed by the rock-bump forecasting and control teams of the mine and the Norilskshakhtstroy company, showed the 'Not Hazardous' category in all cases. However, the progress of mining operations towards the Norilsk-Kharaelakh Fault may lead to deterioration in the condition of mine workings. This can be manifested through rock exfoliation from the walls of the advance workings of the safety layer in highly and extremely faulted rocks. In addition, permanent workings, which are one of the most critical structures of the production level and which will be used until the development of the deposit area adjacent to the Norilsk-Kharaelakh Fault is completed, will be maintained in increasingly difficult conditions. The article describes recommendations for mining operations in the fault area with account for the current mining and geomechanical situation and the potential for its change.

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