THE DYNAMIC CHARACTERISTICS OF THE PLANTAR PRESSURE IN THREE TYPICAL BADMINTON FOOTWORK PATTERNS

The purpose of this study was to investigate the dynamic characteristics of plantar pressure in the three-badminton footwork patterns (left-forward lunging step, LFLS, right-forward lunging step, RFLS, backward revolve to jump, BRJ). Twelve elite national-level male badminton athletes were recruited while performing the three typical footwork patterns tests in a laboratory-simulated badminton court. The results of the present study demonstrate that the normalized mean peak pressures (MPP) were significantly higher under the hallux and the 1st to 2nd metatarsals than other areas in the toe-off (TO) phase when performing the three footwork patterns. In the process of touching down (TD), both LFLS and RFLS showed significantly higher loads on the rearfoot and the lateral of the foot. Thus, the badminton players should be paying attention to modulating the load strategies on the front-foot, rear-foot, and lateral of the foot regions when performing the different footwork patterns, and select the appropriate footwear that can disperse the higher loads of the target areas to avoid excessive concentration of the plantar pressures

A review on biomass as a substitute energy source: Polygeneration influence and hydrogen rich gas formation via pyrolysis

Hydrogen rich gas production and advantages of polygeneration during biomass conversation through pyrolysis were extensively reviewed in this paper. Different innovative pyrolysis setups and the effect of reaction conditions such as pressure, temperature, catalyst type, biomass type, and reactor type on the formation of hydrogen and other value-added chemicals has been exploited. High temperatures and pressures together with application of catalysts was reported to favour the enhancement of hydrogen by promoting secondary pyrolysis reactions and hence the production of H2 gas. Compared to one-stage pyrolysis systems, pyrolysis data from two-stage pyrolysis reaction systems reported improved production of hydrogen and value-added chemicals due to the reforming of volatile matter in the second stage reactor. The polygeneration effect of biomass pyrolysis has also been reviewed, and it was observed that the polygeneration systems were significantly vital in covering the demand and supply of renewable energy

On-design operation and performance characteristic of custom engine

The purpose of this study is to investigate the design point performance of a custom engine via GasTurb software. In this study, a turbojet engine model is simulated without afterburners and limited to design point (DP) simulation at a speed of 15,000 rpm. The input parameters such as pressure ratio (PR) for the main components, the mechanical and burner efficiency, and isotropic PR for compressor and turbine have been identified for a custom engine as a design point. The results compared at different levels of the condition using GasTurb-13 and GSP-11 software. It was found that each software was able to provide similar results at various conditions tested. There are small differences in the values for the fuel flow and specific fuel consumption. Also, the same results were obtained at the baseline point. Furthermore, the heating value has a primary effect on specific fuel consumption. It was also found that the optimal thrust value was at 34.2 kN, and the best value for optimal specific fuel consumption was 20.9 g/kN.s. The main factors affecting biofuel properties are calorific value and viscosity. When the calorific value of the fuel is reduced, the thrust FN and specific fuel consumption increase. For example, Methanol and Ethanol recorded the highest amount of fuel consumption, which is 54.72 g/KN.s and 47.56 g/(KN.s), respectively. This is because they have the highest mass fuel flow ( 1.79 kg/s for Methanol, and 1.54 kg/s for Ethanol) than other types of fuel, while the mass fuel flow for green diesel (0.78 kg/s) was lower than other fuels, so its specific fuel consumption (22.11 g/(KN.s) was lesser than other fuels

Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study - Part 2: Philippine receptor observations of fine-scale aerosol behavior

Abstract. The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3–12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model. Indeed, the Navy Aerosol Analysis and Prediction System (NAAPS) simulations captured longer period aerosol events quite well but largely failed to capture the timing of high-frequency phenomena. Ultimately, the research findings of these cruises demonstrate the real world challenges of satellite-based missions, significant aerosol life cycle questions such as those the future Aerosol/Clouds/Ecosystems (ACE) will investigate, and the importance of small-scale phenomena such as sea breezes, squall lines, and nucleation events embedded within SWM patterns in dominating aerosol life cycle and potential relationships to clouds

A Network-Based Approach to Investigate the Pattern of Syndrome in Depression

In Traditional Chinese Medicine theory, syndrome is essential to diagnose diseases and treat patients, and symptom is the foundation of syndrome differentiation. Thus the combination and interaction between symptoms represent the pattern of syndrome at phenotypic level, which can be modeled and analyzed using complex network. At first, we collected inquiry information of 364 depression patients from 2007 to 2009. Next, we learned classification models for 7 syndromes in depression using naïve Bayes, Bayes network, support vector machine (SVM), and C4.5. Among them, SVM achieves the highest accuracies larger than 0.9 except for Yin deficiency. Besides, Bayes network outperforms naïve Bayes for all 7 syndromes. Then key symptoms for each syndrome were selected using Fisher's score. Based on these key symptoms, symptom networks for 7 syndromes as well as a global network for depression were constructed through weighted mutual information. Finally, we employed permutation test to discover dynamic symptom interactions, in order to investigate the difference between syndromes from the perspective of symptom network. As a result, significant dynamic interactions were quite different for 7 syndromes. Therefore, symptom networks could facilitate our understanding of the pattern of syndrome and further the improvement of syndrome differentiation in depression

Aerosol Meteorology of the Maritime Continent for the 2012 7SEAS Southwest Monsoon Intensive Study - Part 2: Philippine Receptor Observations of Fine-Scale Aerosol Behavior

The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere’s thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3–12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model. Indeed, the Navy Aerosol Analysis and Prediction System (NAAPS) simulations captured longer period aerosol events quite well but largely failed to capture the timing of high-frequency phenomena. Ultimately, the research findings of these cruises demonstrate the real world challenges of satellite-based missions, significant aerosol life cycle questions such as those the future Aerosol/Clouds/Ecosystems (ACE) will investigate, and the importance of small-scale phenomena such as sea breezes, squall lines, and nucleation events embedded within SWM patterns in dominating aerosol life cycle and potential relationships to clouds

Prediction of recurrence of ischemic stroke within 1 year of discharge based on machine learning MRI radiomics

PurposeThis study aimed to investigate the value of a machine learning-based magnetic resonance imaging (MRI) radiomics model in predicting the risk of recurrence within 1 year following an acute ischemic stroke (AIS).MethodsThe MRI and clinical data of 612 patients diagnosed with AIS at the Second Affiliated Hospital of Nanchang University from March 1, 2019, to March 5, 2021, were obtained. The patients were divided into recurrence and non-recurrence groups according to whether they had a recurrent stroke within 1 year after discharge. Randomized splitting was used to divide the data into training and validation sets using a ratio of 7:3. Two radiologists used the 3D-slicer software to label the lesions on brain diffusion-weighted (DWI) MRI sequences. Radiomics features were extracted from the annotated images using the pyradiomics software package, and the features were filtered using the Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis. Four machine learning algorithms, logistic regression (LR), Support Vector Classification (SVC), LightGBM, and Random forest (RF), were used to construct a recurrence prediction model. For each algorithm, three models were constructed based on the MRI radiomics features, clinical features, and combined MRI radiomics and clinical features. The sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (AUC) were used to compare the predictive efficacy of the models.ResultsTwenty features were selected from 1,037 radiomics features extracted from DWI images. The LightGBM model based on data with three different features achieved the best prediction accuracy from all 4 models in the validation set. The LightGBM model based solely on radiomics features achieved a sensitivity, specificity, and AUC of 0.65, 0.671, and 0.647, respectively, and the model based on clinical data achieved a sensitivity, specificity, and AUC of 0.7, 0.799, 0.735, respectively. The sensitivity, specificity, and AUC of the LightGBM model base on both radiomics and clinical features achieved the best performance with a sensitivity, specificity, and AUC of 0.85, 0.805, 0.789, respectively.ConclusionThe ischemic stroke recurrence prediction model based on LightGBM achieved the best prediction of recurrence within 1 year following an AIS. The combination of MRI radiomics features and clinical data improved the prediction performance of the model

A mechanistic study of coal swelling and char structure evolution during pyrolysis - experiments and model predictions

Research Doctorate - Doctor of Philosophy (PhD)This work presents a systematic study on swelling and char formation during pyrolysis of pulverized coal using both experimental measures and modelling approach. By using the density fraction samples, i.e. Fl.25, Fl.30, Fl.35, Fl.50 and Sl.50, prepared using the sink-float method, transient observations using a single particle reactor (SPR) and the analysis of DTF (drop tube furnace) chars prepared at atmospheric pressure consistently reveal the heterogeneity of the pyrolysis behaviour and char structures from pulverized coal. Particles from the light density fractions (i.e. Fl.25 and Fl.30) experience intensive softening and swelling during heating. Apparent bubbling phenomena have been observed in single particle experiments, which is responsible for the coal swelling. On the contrary, particles from heavy density fraction samples, i.e. Fl .50 and S 1.50, do not exhibit softening and swelling. Correspondingly, the porosity of DTF chars decreases markedly for heavy density fraction samples. It is observed that Group I chars (porous structure) are mainly generated from two light density fraction samples, while Group III chars (solid structure) are yielded from heavy density fractions. The medium density faction sample contains a mixture of different types of chars. The heterogeneity of char characteristics is attributed to the variations in the raw coal properties among different density fractions. The characters of PEFR (pressurized entrained flow reactor) chars prepared at the elevated pressure of 2.0 MPa are examined, and compared with PDTF (pressurized drop tube furnace) and DTF chars. Consistent with previous work, the results suggest that high pressures increase the swelling, the number of bubbles and char porosity, while the population of both the cenospheric char and the solid char decreases at elevated pressures. A mathematical model for coal swelling and char structure formation of single coal particles during devolatilization is developed based on a simplified multi-bubble mechanism. The char formation has been considered as two successive steps: the multibubble stage followed by a single bubble stage. During the multi-bubble stage, the rupture of bubbles is a rate-controlled process, during which the volatile release is governed by the bubble rupture rate. When the cenospheric char structure is formed, the single bubble model applies. During this stage, the bubble rupture is controlled by the wall stress, and the volatiles are released through both bubble ruptures and direct diffusion of volatiles to the particle surface. The sensitivity study has been carried out, based on which the parameters for the present modelling work have been determined. Comparisons of the model predictions with the experimental data show that the present model predicts the experimental trends of the coal swelling and char structure characteristics under different heating conditions. As an advancement of previous work, the model provides a complete description of the char structure evolution process of pulverized coal during pyrolysis. From the standard parent coal properties of densityfraction samples, the present model predicts the heterogeneity of the char structure from the same coal, and estimates the distribution of char types, i.e., the Group I, II and III chars. The model predicted results agree with the experimental measurements. Overall, the experimental observations and the model predictions from this study consistently reveal the heterogeneity of the char characteristics owing to the heterogeneous nature of coal. In addition to the dominant role of coal macerals, the influence of the ash level in coal on char formation is identified, which extends the current understanding of the heterogeneous nature of coal for char formation. In the meantime, conditions under which coal is heated have a significant impact on char formation. High heating rates increase the swelling ratio, from both the experimental observations and the model prediction. Pressure plays a significant role in char formation, and favours the formation of the foam char structures with a high porosity. An optimum pressure range has been predicted, which is consistent with the literature data

Coal-fired oxyfuel technology status and progress to deployment

As one of the three major CCS technologies, oxy-fuel technology is currently undergoing rapid development with a number of demonstration projects commencing in the development towards commercialization. This paper provides a comprehensive overview of the most recent pilot plants and demonstration projects. Aspects of a roadmap for the deployment of oxy-fuel CCS technology for commercialization are provided with further R&D needs being identified