Changes In Dynamic Characteristics Research Articles

Whole-Brain Functional Connectivity Dynamics Associated with Electroconvulsive Therapy Treatment Response

Background: Major depressive disorder characterized by abnormalities of cognitive functions and mood is one of the leading causes of disability. Electroconvulsive therapy (ECT), which involves a brief electrical stimulation of the anesthesia brain, is the most potent treatment used in patients with depressive episodes (DEP) due to its rapid efficacy. Methods: In this work, we investigated how the human brain dynamically responds to ECT and whether the dynamic responses are associated with treatment outcomes and side-effects in 110 patients with DEP and 60 healthy controls (HCs) via a combination of a fully automated independent component analysis (ICA)-based pipeline and the clustering analysis. Findings: Five reoccurring connectivity states were identified, among which DEP had fewer occurrences in one antagonism state (state 1) with strong positive and negative connectivity. DEP patients increased the occupancy of two states (states 3 and 4) after ECT, resulting in significantly different occurrences of one additional state (state 3) compared to HC. We further found that DEP patients had diminished global meta-state dynamism, two of which recovered to normal after ECT. Interestingly, the changes in dynamic connectivity characteristics were associated with the changes in memory recall and Hamilton Depression Rating Scale of DEP after ECT. Interpretation: These converging results extend current findings on subcortical-cortical dysfunction and dysrhythmia in DEP and demonstrate that ECT might cause a remodeling of brain functional dynamics that underlies antidepressant symptom response and memory function of patients. Funding Statement: This work was supported National Institutes of Health (No. R01MH118695, R01EB020407 and R01MH117107), and China Natural Science Foundation (No. 61773380), Beijing Municipal Science and Technology Commission (No. Z181100001518005). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: Written informed consent was obtained from all participants under protocols approved by the Institutional Review Board (IRB) of UNM and UCLA.

Monitoring the changes of dynamic characteristics of a high-rise building

To assess changes in the dynamic characteristics of the 25-storeyed building of the Kazakhstan Hotel in Almaty, an analysis of instrumental records of the station of engineering seismometric service was carried out. The building is located near the tectonic fault. During two earthquakes, representative instrumental data were obtained at the Seismic Station No. 16 (“High-rise Hotel”), equipped with digital instrumentation and measurement system. The building is twenty-five-storeyed with a stiffening core, built in 1976. Using the ADXL accelerometers and the RSM-32 recorder, high-quality instrumental records of accelerations were obtained in the basement, on the floors and on the roof of the building, and spectral curves β were also built. The peculiar features of the dynamics of the specified building are noted during earthquakes. Periods of the building oscillation on the main and second modes of oscillation were revealed on exposure to a remote earthquake. Comparison of the dynamic characteristics of the house was carried out according to the measurements of 1977 and 2018. It has been established that there is a significant increase in the magnitude of the oscillation period on the first form by 25–48% as compared to the measurements of 1976–1977 over the 40-year period of operation.

Dynamic Changes in Hydrochemical Characteristics and Influencing Factors in the Karst Watershed Flood Process

The hydrochemistry of river water in a karst basin has a rapid response to the rainstorm/flood process, which is an important process of the karst carbon cycle and should not be ignored. Based on the dynamic monitoring of the hydrochemical characteristics of the flood process in the Yangshuo section on November 8-12, 2015, the dynamic change in the main ions and the influencing factors were analyzed, and the concentration and flux of inorganic carbon from different sources were calculated. The results showed that the hydrochemistry types in different stages of the flood area belonged to the Ca-HCO3 type. The ions were mainly sourced from carbonate weathering, and affected by silicate weathering, rainfall, and human activities. Because of the hydrological process, the weathering strength of carbonate rocks sharply weakened at the beginning of the flood, and then gradually increased. The concentrations of HCO3-, Ca2+, and Mg2+ sharply decreased at the beginning of the flood, then gradually increased, and continued to increase in the second flood process because of the waterlogging in the karst system. Because of the waterlogging, the reaction time between water and rock become longer; thus, the concentrations are higher. The dynamic changes in SO42-, Cl-, Na+, and K+ were mainly affected by precipitation and human activities. At the beginning of the flood, the concentrations of SO42-, Cl-, Na+, and K+ increased because the runoff takes more ions sourced from activities. The concentrations of SO42-, Cl-, Na+, and K+ decreased with the decrease of easily transported substances. At the lowest point of concentration, SO42- and Cl- were mainly sourced from precipitation, and Na+ and K+ were mainly sourced from precipitation and silicate weathering. The weathering of carbonates by carbonic acid was the main source of inorganic carbon, accounting for 74.3% of total inorganic carbon on average. Because of the input of sulfuric/nitric acid, the contribution of the weathering of carbonates by sulfuric/nitric acid to the inorganic carbon cannot be ignored, and the contribution increased significantly in the flood, up to 31.7%. The geological carbon sinks before the flood, and during the first and second flood processes in the Yangshuo section were 1.28×108, 5.28×108, and 11.52×108 g·d-1, respectively. The geological carbon sink before the flood was equal to the annual average flux, whereas the geological carbon sink in the flood process was several times that of the annual average flux. Moreover, because of the significant difference in the weathering strength of carbonate rocks during the two floods, there was also a significant difference in the amount of geological carbon sink under the same discharge.

Numerical Vibration Response of Railway Track Retrofitted with Single Degree of Freedom Rail Dampers

A concept and preliminary results of numerical study of changes in the rail track dynamic characteristics are presented in the paper. Change of the characteristics is introduced in order to reduce noise emissions. The theoretical relationship between the studied track dynamic characteristics (TDR - Track Decay Rate) and noise was briefly explained, and then the methodology of FEM modelling for the standard test simulation was described. Three mass modification variants and two rail types were analyzed. Damper connection were modeled as viscoelastic joint. The rail track vibrations were analyzed in both (vertical and lateral) directions separately. Numerical study shows correlation between the railroad track mass increase and its dynamic characteristics and thus the noise emission. Applying dampers with proposed parameters results in more efficient vibration and noise mitigation in lateral direction.

A Pilot Study of Third-Generation Dual-Source Computed Tomography for the Assessment of Global Dynamic Changes in Left Ventricular Structure and Function in a Porcine Model of Acute Myocardial Infarction.

BackgroundFirst-generation and second-generation dual-source computed tomography (DSCT) are useful for analyzing left ventricle (LV) structure and function. This pilot study aimed to investigate the feasibility and role of third-generation DSCT for the evaluation of dynamic changes in LV structural and functional characteristics in a Diannan small-ear pig model of acute myocardial infarction (AMI).Material/MethodsThe model of AMI was established by balloon occlusion of the distal third of the left anterior descending (LAD) coronary artery in 14 Diannan small-eared pigs. Third-generation DSCT was performed to observe dynamic changes in LV structure and function before and after AMI was induced, with a follow-up period of 30 days.ResultsThe mean structural measurements at baseline included interventricular septum thickness (8.50±0.90 mm), LV anterior wall thickness (8.40±1.30 mm), LV posterior wall thickness (7.80±1.20 mm), LV end-diastolic dimension (LVEDD) (45.00±4.90 mm), and LV end-systolic dimension (LVESD) (25.90±4.10 mm). The mean functional measurements at baseline included the LV end-diastolic volume (LVEDV) (74.62±13.54 ml), LV end-systolic volume (LVESV) (23.06±7.46 ml), LV ejection fraction (LVEF) (69.29±6.83%), LV mass (86.35±14.02 g), stroke volume (SV) (51.56±9.77 ml), and cardiac output (CO) (4.22±2.14 l/min). Trends of time-dependent changes were observed for LVESV, LVEF, SV, and CO, but not for LVEDV or LV mass.ConclusionsThird-generation DSCT was validated as a tool for assessing dynamic changes in LV global function in a porcine model of AMI.

Dynamic characteristics of high-speed railway vehicle with axle box bearing faults

Based on the motion characteristics of axle box bearings and taking high-speed railway vehicles as the research object, a vertical dynamic model of 17-DOF car body-bogie-axle box bearings-wheel set is proposed. Aiming at the surface fault of axle box bearing, the New-Mark fast numerical integration method is used to simulate and analyze. The dynamic characteristics of railway vehicle under early failure of axle box bearing on inner ring and outer ring raceway surface are studied. The vibration characteristics of axle box bearings under different fault degrees and different vehicle speeds (axle box bearing speed) are analyzed. The changes of vehicle dynamic performance and vibration characteristics under fault evolution are discussed. The analysis results show that the vibration of car body and bogie is little affected by the early fault of axle box bearing; with the deepening of the fault degree, the vertical vibration acceleration and displacement of axle box bearing are increasing; with the increase of vehicle speed, the motion state of axle box bearing undergoes a change from periodic motion, quasi-periodic motion to chaotic motion. Finally, the dynamic simulation results of axle box bearing fault evolution in high-speed vehicle system are validated on the experimental platform. The research work has certain reference value for vehicle condition tracking and monitoring.

Hardware- and Software-in-the-Loop Simulation for Parameterizing the Model and Control of Synchronous Condensers

The rapid increase of converter-based generation in grids causes significant changes in system dynamic characteristics. These changes require verification and testing of the reliability, optimization, and functionality of power system elements and controllers, which become more important for guaranteeing a secure operation. This paper first introduces a hardware-in-the-loop setup of an automatic voltage regulator (AVR) control system and then proposes a software-in-the-loop (SiL) setup for the parameterization of an IEEE standard AVR/excitation system model and a power oscillation damping (POD) controller of synchronous condenser. The AVR hardware is interfaced with a simulated grid in real-time digital simulator (RTDS) using EMT simulation to evaluate its control functions. Parameter optimization for the POD and the AVR simulation model by SiL simulation is implemented in a closed loop between RTDS and MATLAB/Simulink interfaced through OPC to satisfy the optimization objectives. By the tests executed on the future Western Danish power system, parameter optimization of the POD and IEEE standard AVR model, and the function of AVR hardware are successfully implemented and verified.

Stability Research Considering Non-Linear Change in the Machining of Titanium Thin-Walled Parts.

Aiming to solve the problem whereby the damping process effect is significant and difficult to measure during low-speed machining of titanium alloy thin-walled parts, the ploughing coefficient of the flank face is obtained based on the frequency-domain decomposition (FDD) of the measured vibration signal and the energy balance principle, and then the process-damping prediction model is obtained. Aiming to solve the problem of non-linear change of dynamic characteristics of a workpiece caused by the material removal effect in the machining of titanium alloy thin-walled parts, a prediction model of dynamic characteristics of a workpiece is established based on the structural dynamic modification method. Meanwhile, the effect of material removal on the process-damping coefficient is studied, and the internal relationship between the process-damping coefficient and the dynamic characteristics of the workpiece is revealed. The stability lobe diagram is obtained by the full discretization in the titanium alloy milling process. The correctness of the model and stability prediction is verified by experiments under different working conditions. It is found that the coupling characteristics of process-damping and workpiece dynamic characteristics control the stability of the milling process. The research results can provide theoretical support for accurate characterization and process optimization of titanium alloy thin-walled workpiece milling.

Changes in dynamic left ventricular function, assessed by the strain-volume loop, relate to reverse remodeling after aortic valve replacement.

Aortic valve replacement (AVR) leads to remodeling of the left ventricle (LV). Adopting a novel technique to examine dynamic LV function, our study explored whether post-AVR changes in dynamic LV function and/or changes in aortic valve characteristics are associated with LV mass regression during follow-up. We retrospectively analyzed 30 participants with severe aortic stenosis who underwent standard transthoracic echocardiographic assessment before AVR [88 (IQR or interquartile range: 22-143) days], post-AVR [13 (6-22) days], and during follow-up [455 (226-907) days]. We assessed standard measures of LV structure, function, and aortic valve characteristics. Novel insight into dynamic LV function was provided through a four-chamber image by examination of the temporal relation between LV longitudinal strain (ε) and volume (ε-volume loops), representing the contribution of LV mechanics to volume change. AVR resulted in immediate changes in structural valve characteristics, alongside a reduced LV longitudinal peak ε and improved coherence between the diastolic and systolic part of the ε-volume loop (all P < 0.05). Follow-up revealed a decrease in LV mass (P < 0.05) and improvements in LV ejection fraction and LV longitudinal peak ε (P < 0.05). A significant relationship was present between decline in LV mass during follow-up and post-AVR improvement in coherence of the ε-volume loops (r = 0.439, P = 0.03), but not with post-AVR changes in aortic valve characteristics or LV function (all P > 0.05). We found that post-AVR improvements in dynamic LV function are related to long-term remodeling of the LV. This highlights the potential importance of assessing dynamic LV function for cardiac adaptations in vivo.NEW & NOTEWORTHY Combining temporal measures of left ventricular longitudinal strain and volume (strain-volume loop) provides novel insights in dynamic cardiac function. In patients with aortic stenosis who underwent aortic valve replacement, postsurgical changes in the strain-volume loop are associated with regression of left ventricular mass during follow-up. This provides novel insight into the relation between postsurgery changes in cardiac hemodynamics and long-term structural remodeling, but also supports the potential utility of the assessment of dynamic cardiac function.

Interleukin-22 receptor 1 is expressed in multinucleated giant cells: A study on intestinal tuberculosis and Crohn's disease.

BACKGROUNDIt is challenging to distinguish intestinal tuberculosis from Crohn’s disease due to dynamic changes in epidemiology and similar clinical characteristics. Recent studies have shown that polymorphisms in genes involved in the interleukin (IL)-23/IL-17 axis may affect intestinal mucosal immunity by affecting the differentiation of Th17 cells.AIMTo investigate the specific single-nucleotide polymorphisms (SNPs) in genes involved in the IL-23/IL-17 axis and possible pathways that affect susceptibility to intestinal tuberculosis and Crohn's disease.METHODSWe analysed 133 patients with intestinal tuberculosis, 128 with Crohn’s disease, and 500 normal controls. DNA was extracted from paraffin-embedded specimens or whole blood. Four SNPs in the IL23/Th17 axis (IL22 rs2227473, IL1β rs1143627, TGFβ rs4803455, and IL17 rs8193036) were genotyped with TaqMan assays. The transcriptional activity levels of different genotypes of rs2227473 were detected by dual luciferase reporter gene assay. The expression of IL-22R1 in different intestinal diseases was detected by immunohistochemistry.RESULTSThe A allele frequency of rs2227473 (P = 0.030, odds ratio = 0.60, 95% confidence interval: 0.37-0.95) showed an abnormal distribution between intestinal tuberculosis and healthy controls. The presence of the A allele was associated with a higher IL-22 transcriptional activity (P < 0.05). In addition, IL-22R1 was expressed in intestinal lymphoid tissues, especially under conditions of intestinal tuberculosis, and highly expressed in macrophage-derived Langhans giant cells. The results of immunohistochemistry showed that the expression of IL-22R1 in patients with Crohn's disease and intestinal tuberculosis was significantly higher than that in patients with intestinal polyps and colon cancer (P < 0.01).CONCLUSIONHigh IL-22 expression seems to be a protective factor for intestinal tuberculosis. IL-22R1 is expressed in Langhans giant cells, suggesting that the IL-22/IL-22R1 system links adaptive and innate immunity.

A stream-sensitive distributed approach for configuring cascaded classifier topologies in real-time large-scale stream mining systems

Stream mining systems have received a great deal of attention in recent years. These systems process incoming data streams from different sources and extract high-level semantic features from them. They do this by passing data streams through an ensemble of classifiers. Owing to dynamic changes in characteristics of the data streams, these classifiers need to be configured dynamically to maximize the performance of the system. As a challenge, different data streams from different sources have different specifications from each other. This causes treating all the incoming data streams identically by a common topology configuration to be not appropriate for an optimal stream mining. Hence, an approach is required which allows each data stream to be processed by consideration of its own specifications. In this paper, by implementing a buffer for each source and using a time-sharing solution, we propose a distributed approach to solve the aforementioned problem for cascaded classifier topologies. We first formally define a utility metric which captures both the performance and the delay of a binary filtering classifier system. We then propose our solution for a base case and evolve it step by step until reaching the most general case for cascaded topologies. We finally test and compare our approach with the state-of-the-art solution on a text detection scenario from the incoming video streams to the system.

Adaptive Dual Extended Kalman Filter Based on Variational Bayesian Approximation for Joint Estimation of Lithium-Ion Battery State of Charge and Model Parameters

An accurate state of charge (SOC) estimation is vital for the safe operation and efficient management of lithium-ion batteries. At present, the extended Kalman filter (EKF) can accurately estimate the SOC under the condition of a precise battery model and deterministic noise statistics. However, in practical applications, the battery characteristics change with different operating conditions and the measurement noise statistics may vary with time, resulting in nonoptimal and even unreliable estimation of SOC by EKF. To improve the SOC estimation accuracy under uncertain measurement noise statistics, a variational Bayesian approximation-based adaptive dual extended Kalman filter (VB-ADEKF) is proposed in this paper. The variational Bayesian inference is integrated with the dual EKF (DEKF) to jointly estimate the lithium-ion battery parameters and SOC. Meanwhile, the measurement noise variances are simultaneously estimated in the SOC estimation process to compensate for the model uncertainties, so that the adaptability of the proposed algorithm to dynamic changes in battery characteristics is greatly improved. A constant current discharge test, a pulse current discharge test, and an urban dynamometer driving schedule (UDDS) test are performed to verify the effectiveness and superiority of the proposed algorithm by comparison with the DEKF algorithm. The experimental results show that the proposed VB-ADEKF algorithm outperforms the traditional DEKF algorithm in terms of SOC estimation accuracy, convergence rate, and robustness.

Dynamic cell type-specific expression of Nrf2 after traumatic brain injury in mice.

Nrf2 plays a pivotal role in antioxidant response and anti-inflammation after traumatic brain injury (TBI), and its deletion aggravates TBI-induced brain damage. Previous studies have demonstrated that Nrf2 is activated post TBI, but dynamic changes in expression and cell type-specific characteristics remain unclear. In this study, the Feeney weight-drop contusion model was conducted to mimic TBI, and the ipsilateral cerebral cortex was collected at 1, 3, 7 and 14days post TBI (dpi). Nrf2 protein levels were observed by western blot. Cell type-specific localization of Nrf2 after TBI was detected at different time intervals by double immunofluorescence staining. NeuN, GFAP, IBA1 and NG2 were used as cell type-specific markers to neurons, astrocytes, microglia and NG2 glia, respectively. After TBI, Nrf2 protein levels peaked at 1 dpi. Robust transient Nrf2 accumulation was co-localized with neurons, which was predominant at 1 dpi. Continuous weak Nrf2 expression was detected in activated astrocytes, and the number of double positive cells peaked at 7 dpi. Inducible widespread immunostaining of Nrf2 was observed in the nucleus of the microglia, and the number of Nrf2+ microglia peaked at 7 dpi. In addition, we also explored colocalization of Nrf2 in NG2 glia, in which the percentage of Nrf2+ in NG2 glia reached a climax at 3 dpi. This study reveals that the accumulation of endogenous Nrf2 might mediate different pathophysical roles in neurons and glias after TBI, the cell-type specific and time-dependent expression provide insights to explain the roles of Nrf2 in different neural cells.

Laboratory Testing to Research the Micro-Structure and Dynamic Characteristics of Frozen–Thawed Marine Soft Soil

The use of artificial freezing can change the mechanical properties of marine clay. In the construction of cross passages in metro tunnels in which the artificial ground freezing (AGF) method is applied, freeze–thaw circulation and cyclic loading could weaken the engineering properties of the clay, thus resulting in differential settlement. In this paper, the authors studied the dynamic properties of frozen–thawed soils under cyclic loading, with the help of dynamic triaxial testing. According to the dynamic triaxial test results and the images from scanning electron microscopy (SEM), the authors explained the weakening effect of both the freeze–thaw cycle and dynamic loading on soft soil. After freezing, the number of large pores increased. In addition, after cyclic loading, the pore structure of the soil showed a tendency towards compaction, which led to the large pores breaking into small ones. Subsequently, the potential reasons for the change of macroscopic dynamic characteristics were explained from a micro-scale point of view.

Temporal and spatial evolution of a deep-reaching anticyclonic eddy in the South China Sea

The temporal and spatial evolution of a deep-reaching anticyclonic eddy (AE) is studied using a combination of satellite measurements, moored observations and ocean model reanalysis data in the South China Sea (SCS). Three evolutionary stages in eddy’s lifecycle are identified from changes in eddy dynamical characteristics estimated from satellite altimetry: birth (22 days), growth (64 days), and decay (47 days). Similar patterns are also distinguished from dynamic signals in HYCOM. Further, flows reversal and upwelling of cold water below 1500 m were captured by the in-situ records when this energetic, highly nonlinear and long-lived (over 19 weeks) AE passed by our mooring position. Its detailed vertical structure is examined through temperature anomalies, vertical shear of horizontal velocities, and horizontal streamlines estimated from ocean model reanalysis data. Results from the model reveal a mesoscale AE with first-mode baroclinic structure: a bowl-shaped anticyclonic flow in the upper ocean connected to a slant-cylinder cyclonic flow at depth, with a transition layer at depths between 400 and 700 m. It is in good agreement with moored observations but showing a shallower transition depth, suggesting a slight deficiency in the model due to limited deep-sea observations. Last, we estimate eddy heat transport at different depths and stages along the AE’s path based on the model data. The result reveals that pronounced heat fluxes occur during growth stage (depths 400 m), counting for 73.03% of the total value. In the decay stage, major heat transport occurs at deeper depth (depths > 700–1500 m). Dynamical characteristics suggest that the vertical structure and temporal evolution of the eddy play significant roles in basin-scale movement and heat transferring. Considering that mesoscale eddies are ubiquitous in the SCS, our results support a recently-proposed mechanism, whereby upper ocean flows produce changes in the deep-sea circulation, potentially influencing boundary layer dynamics. For the first time to track and link an individual AE observed by satellite altimetry and ocean model, comparisons indicate that assimilative HYCOM outputs may be useful for examining the deep ocean properties within the SCS, especially under the impact of such an intensified surface-detected eddy.

Application Features of the Engineering Seismometric Method of Survey and Monitoring the Technical Condition of Buildings and Structures

This paper considers the history of the development and using the engineering seismometric method of the examination and monitoring of buildings and structures for various purposes. The sequence of seismometric surveys and the justification of the process of periodic or continuous monitoring the technical condition by the changing of dynamic and elastic characteristics of the object is shown. Based on the long-term work experience, the authors presented the main mistakes made during the seismometric surveys and monitoring the technical condition of buildings and structures

Changes in rotor response characteristics based diagnostic method and its application to identification of misalignment

Misalignment is one of the commonly encountered faults that generate excessive rotor vibration. The diversity of its characteristic frequency brings great trouble for fault diagnosis. Especially when misalignment-induced vibration manifests it as only synchronous (1x) component, properly diagnosing this fault becomes more difficult, since other faults often show the similar frequency signature. To extract discriminative information from the view of fault development, a diagnostic method is proposed with comprehensive utilization of changes in rotor static and dynamic response characteristics. First, rotor static and dynamic responses are deduced, the average rotor centerline (ARC) plot and orbit plot are introduced separately to represent these responses. The results indicate that ARC position changes considerably and 1x-orbit synchronously becomes more flattened with the increase of misalignment, when all machine operating conditions remain constant. Combination of these symptoms can be used to better distinguish misalignment from other 1x vibration problems related to changes in unbalance force, e.g. rotor unbalance and temporary thermal bend. Subsequently, the combination plot and its feature trend plot of ARC and 1x-orbit are developed to fully describe the changes in rotor static and dynamic responses with time and their correlation. Finally, the proposed method was successfully applied to 1x vibrations of a NOx compressor and a flue gas expander.

Shake table tests on the two-storey dry-joint stone masonry structures reinforced with timber laces and steel wires

During the Nepal Gorkha Mw7.8 earthquake, the two-storey stone masonry buildings experienced the most severe damage among all structural types in the seismically affected areas. However, this type of construction will continue to be used in the vast areas of the Himalayan belt due to the less developed economies and limited access to cement and steel. The experimental verification of different reinforcement techniques applicable in these areas is urgently needed. In this paper, three scaled two-storey stone masonry houses with timber floors were tested on a shake table under various seismic scenarios to verify the effects of reinforcement techniques using timber laces and gabion wires. The seismic performances of the models with and without reinforcement were evaluated and compared through crack pattern development, the structural damage and failure modes, and the changes in dynamic characteristics. The experimental results are presented, analysed and discussed. The un-reinforced two-storey model completely failed at a PGA of 0.4 g; while the model strengthened with timber laces experienced only local failure at a PGA of 0.51 g, and the reinforced model using both timber laces and gabion wires remained intact with limited damage at a PGA of 0.92 g. This research confirmed that the seismic performance of two-storey stone masonry structures could be substantially improved when inexpensive and easy-to-implement reinforcement techniques using local materials were utilized.

Exploiting community structure, interactions and functional characteristics of fungi involved in the biodrying of storage sludge and beer lees

In this study, the dynamic changes in fungal biodiversity, community structure, fungal associations and functional characteristics were investigated in the biodrying of storage sludge and beer lees by using high throughput sequencing, network and correlation matrix analyses, and FUNGuild database. Additionally, a hypothetical model was provided to better understand the biodrying system. The results showed that fungal diversity decreased after biodrying, while community richness increased in the mesophilic stage and decreased as biodrying progressed. Fungal communities differed in different stages of the biodrying process. Ascomycota and Basidiomycota were the dominant phyla throughout the biodrying process, while Pichia was the dominant genus in the thermophilic stage. Network and correlation matrix analyses provided useful tools for insight into the fungal interactions, allowing us to propose a conceptual model of how succession in fungal associations regulates the dynamics of biodrying systems. Biodrying treatment had a significant effect on fungal trophic modes, with most pathogenic fungi fading away over the process, illustrating that biodrying is an effective bio-treatment method to eliminate pathogenic fungi. These findings provide information that elucidates the fungal interactions and functional characteristics during the biodrying process.

A hybrid structural health monitoring technique for detection of subtle structural damage

There is greater significance in identifying the incipient damages in structures at the time of their initiation as timely rectification of these minor incipient cracks can save huge maintenance cost. However, the change in the global dynamic characteristics of a structure due to these subtle damages are insignificant enough to detect using the majority of the current damage diagnostic techniques. Keeping this in view, we propose a hybrid damage diagnostic technique for detection of minor incipient damages in the structures. In the proposed automated hybrid algorithm, the raw dynamic signatures obtained from the structure are decomposed to uni-modal signals and the dynamic signature are reconstructed by identifying and combining only the uni-modal signals altered by the minor incipient damage. We use these reconstructed signals for damage diagnostics using ARMAX model. Numerical simulation studies are carried out to investigate and evaluate the proposed hybrid damage diagnostic algorithm and their capability in identifying minor/incipient damage with noisy measurements. Finally, experimental studies on a beam are also presented to compliment the numerical simulations in order to demonstrate the practical application of the proposed algorithm.