Miracle-dz/UniFAR-FTUs huggingface dataset:
Strategies for overcoming the effect of temperature on guided wave structural health monitoring

Changes in environmental conditions, and in particular temperature, limit the sensitivity of guided wave structural health monitoring (SHM) systems that use reference signal subtraction. The limitation on sensitivity is the size of the residual signal left after reference signal subtraction that arises from imperfect subtraction of the signals from benign structural features. The sensitivity can be improved by decreasing the spacing between sensors but the effect of temperature is so strong that it is doubtful whether the resulting SHM system is economically viable. This provides the motivation for searching for alternative strategies to improve sensitivity. One possibility is to record an ensemble of reference signals over a range of temperatures and then use the signal in the ensemble that best matches a subsequent signal for subtraction. Experimental results show that this provides an improvement in sensitivity of around 35 dB. It does however require a large database of signals and there is the potential concern that the subtraction of the best match signal may somehow also remove a genuine signal from damage. Another possibility is signal processing to improve sensitivity. A uniform temperature change to a structure results in a change in wave velocity and a dilation of the structure itself. The net effect is a dilation of the arrival times of each wave-packet in a guided wave signal. An obvious strategy to compensate for this effect is to apply the inverse dilation to the time-axis. However, this does not compensate for the effect exactly since the temperature change does not dilate individual wave-packets. An alternative and exact compensation scheme is presented and its practical application is discussed.
Influence of Nonlinear Effects on the Limit Cycle in a Combustion Chamber Equipped With Helmholtz Resonator

The influence of the introduction of a Helmholtz resonator as a passive damper in a gas turbine combustion chamber on the bifurcation mechanism that characterizes the transition to instability is investigated. Bifurcation diagrams are tracked in order to identify the conditions for which the machine works in a stable zone and which are the operative parameters that bring the machine to unstable conditions. This work shows that a properly designed passive damper system increases the stable zone, moving the unstable zone and the bistable zone (in the case of a subcritical bifurcation) to higher values of the operative parameters, while have a limited influence on the amplitude of limit cycle. In order to examine the effect of the damper, a gas turbine combustion chamber is first modeled as a simple cylindrical duct, where the flame is concentrated in a narrow area at around one quarter of the duct. Heat release fluctuations are coupled to the velocity fluctuations at the entrance of the combustion chamber by means of a nonlinear correlation. This correlation is a polynomial function in which each term is an odd-powered term. The corresponding bifurcation diagrams are tracked and the passive damper is designed in order to increase the stability zone, so reducing the risk to have an unstable condition. Then both plenum and combustion chamber are modeled with annular shape and the influence of Helmholtz resonators on the bifurcation is examined.Copyright © 2014 by ASME
Control Strategy of Photovoltaic Grid-Connected Inverter

As a key component of photovoltaic grid generation system, grid-connected inverter plays an important role, and its control is paid more attention to by people. After the introduction of principle and structure of grid-connected photovoltaic inverter, the paper describes the control objectives of grid-connected, represents several current control strategies of grid-connected inverter in detail, and indicates its future development trend finally.
Stormwater particles and their sampling using passive devices

[Abstract]: Total Suspended Solids (TSS) is commonly used as a measure of particle concentration in stormwater. The breakdown of TSS into subgroups based on particle size is an important step in describing stormwater characteristics. A simple classification system is proposed that divides solids into four size ranges; Very Fine (VFPs, 500μm). The use of passive samplers to obtain unbiased, flow-weighted samples of non-Coarse particles was investigated. Two alternative passive samplers referred to as a flow splitter and an orifice and weir device were designed, constructed and tested. The flow splitter outperformed the orifice and weir device in terms of sampling accuracy. Based on hydraulic testing up to 5 L/s, the flow splitter was able to accurately (±2% error) obtain a constant sample volume: flow volume ratio compared to a ±15% error for the orifice and weir. Based on sediment testing, the performance of the flow splitter in obtaining VFP and FP samples was similar to that of high frequency grab sampling. Samples collected by the flow splitter matched theoretical concentrations of particles less than 63μm to within ±2% error. All sampling methods significantly underestimated the concentration of particles greater than 63μm (MPs) and more research is needed in this area. Overall, the flow splitter is considered to have significant potential for determining the Event Mean Concentration of stormwater particles.
Coexist?

Human intervention with technology and science, and the need to dominate sometimes lead to unpredictable and seemingly negative results. Unlike most species, humans adapt not simply for survival, but also for social acceptance, wealth, and prosperity. We insist that other species adapt to our ever-changing model of the world or get out of the way.
More water, less energy and reduced CO2 emissions — the Larnaca desalination plant

An objective of the Larnaca seawater desalination plant (LDP) was to reduce specific energy consumption while producing the same or more water while maintaining water quality criteria. A critical water quality issue was the removal of boron to levels such as those defined by the WHO. The LDP (a 10-year BOOT project) has been operating since 2001, and has the challenge of meeting a 1 mg/L boron standard. In order to cope with the boron requirement, the plant is designed with a double-stage RO configuration in order to produce boron concentrations consistently below 1 mg/L. Other innovative design features of the LDP are the eight membranes per pressure vessel, permeate from both ends of the pressure vessels and a fully automated operation. As part of a wider plant operation strategy, the plant processes have been optimized and a stable high plant performance was achieved. Further developments such as the membrane management system have improved the performance of the SWRO process and the operation of the f.
Dynamic Equivalents for Average System Frequency Behavior Following Major Distribances

This paper endeavors to model the effects of governor- turbine dynamics on the average system frequency behavior of a multi- generator system after a major generation loss or load change when the system remains in synchronism. The maximum frequency deviation and the time at which the maximum occurs are the main quantities of interest. Two independent concepts are presented to convert a closed-loop, high dimensional, nonlinear model into approximate, open-loop, low dimensional, linear ones (the delay and the canonical models). The delay model uses pure time delay to model "fast time constants" and valve motion and converts the closed loop model into an open loop one. The canonical model expresses the turbine reheats respo'nse as a linear combination of a set of "basis" functions and provides a basis for combining many machines into one simplified, low dimensional model. The two models can be implemented concurrently, to give a very large reduction in complexity when a multi-machine system is analyzed.
FAULT DIAGNOSIS OF ROTATING MACHINERY THROUGH VISUALISATION OF SOUND SIGNALS

Abstract As a method for diagnosing faults in rotating machinery, attention is being focused on changes in the sound signals generated by bearings. This provides the advantage of making it easier to set up sensors, since sound signals can be measured at a location some distance from the housing of the bearing. However, the signal-to-noise ratio is low compared with the vibration acceleration, which makes it difficult to identify any characteristic difference between the sound signals generated by normal and faulty bearings. This report describes a symmetrised dot pattern (SDP) method, which visualises sound signals in a diagrammatic representation. Using SDP to visualize sound signals measured for fans, it was possible to distinguish differences between normal and faulty bearings. Moreover, through the analysis of sound signals in the time-frequency domain and wavelet analysis, the signal component indicative of a fault was identified. When sound signals were modified by removing the above component, SDP with the modified faulty signal resembled the non-faulty case.
Optimum Design of the PID Controller in Steam Treatment System

Steam manage system is a great delay system. The optimum design is necessary to ensure its speed response, quick follow in concrete system. The paper introduces optimizing digital controller design principle, and builds transfer function of pure lag system and constitutes modal of control system. Based on introducing the dynamic characteristics of the steam treatment system, analyzing the character of object function and determines it, and system emulation is put up on known object function and PID controller is confirmed. Experimental emulation proves the objective function, overshoot and adjustable time of dynamic response have effectively improved in optimized system, and the optimum design of the system is significant by comparing optimized system with unoptimized system.
Optimization of Processing Parameters for Electrolysis and Plasma Polishing

To study influence of temperature and concentration of the polishing solution and the workpiece’s diving depth and spatial orientation in the polishing solution on electrolysis and plasma polishing, orthogonal experiments consisting of four factors at four different levels were performed by using surface roughness of the specimen after 5 minutes of polishing and electric current density in the process of the polishing as experimental indexs based on the polishing mechanism and the mathematic model of surface roughness with polishing time. Primary and secondary order and regularity of the factors affecting the roughness and the electric current density are obtained by means of extreme difference method combined with variance analytic method. Optimal parameter combination focusing on the polishing effects or considering fully the polishing effects, cost and efficiency is proposed.
Remote Monitoring of Outdoor Performance of Low Scale Dye Sensitized Solar Cells for Nanosensors Nodes

This is the first outdoor test of small-scale dye sensitized solar cells (DSC) powering a stand- alone nanosensor node. A solar cell test station (SCTS) has been developed using standard DSC to power a gas nanosensor, a radio transmitter, and the control electronics (CE) for battery charging. The station is remotely monitored through wired (Ethernet cable) or wireless connection (radio transmitter) in order to evaluate in real time the performance of the solar cells and devices under different weather conditions. The 408 cm 2 active surface module produces enough energy to power a gas nanosensor and a radio transmitter during the day and part of the night. Also, by using a programmable load we keep the system working on the maximum power point (MPP) quantifying the total energy generated and stored in a battery. These experiments provide useful data for future outdoor applications such as nanosensor networks.
Thoughts on Product Development Oriented to Sustainability in Organizational Overview

The process of product development is increasingly critical factor for the competitiveness of the companies, especially with the increasing internationalization of markets, increased diversity and reduced product life cycle. Besides, companies must be willing to promote the concepts of sustainability to create products that offer environmental, social and economic benefits while protecting public health, welfare and environmental. Because it is of crucial strategic point within organizations, as part of the thought on the product development process, it was accomplished a literature review with the aim of understanding how sustainability is being addressed in product development models. The selected models were verified through a content analysis in order to identify and map the activities of the development process that were related to sustainable product design (presented in a descriptive framework). The study results show that the discussion on models of product development oriented to sustainability is still very fragmented in the literature and there is a concentration of approach to the topic in phases related to informational design and conceptual design. Nevertheless, it is still necessary to deepen the application of concepts related to sustainability in product development from an overview of their processes, since evolution has occurred most often in practices directed at engineering processes and aids tools. The analysis of the articles also found that companies, whether by legal pressures, market or consumers, need to adopt sustainability systemically into their strategies, where all parties are considered. The final product should incorporate the concepts related to the triple bottom line throughout all phases of the project in order to optimize the development process and ensure truly sustainable product. It is believed that companies that adopt these more sustainable practices for their products will certainly change the behaviour related to consumer, social equity and preserving the planet.
Construction of an optimum system design method considering product lifecycle

This paper proposes an optimum system design method that especially considers product lifecycles and aims to help designers make effective decisions during the product design phase. By considering and estimating all lifecycle factors of cost and environmental impact in addition to the product performance, this method facilitates development of optimum design solutions that incorporate requirements pertaining to the product's entire lifecycle. Furthermore, quantitative estimation of lifecycle factors enables the numerical expression of optimum solutions, rather than depending primarily on experiment and designer intuition. To demonstrate the effectiveness of the proposed method, this paper develops an optimum system design method for a milling machine as an example of a machine product designed for long term use. The lifecycle cost and the lifecycle environmental impact are generally expressed as the summation of each value during manufacturing phase, usage phase, disposal phase and recycling phase. In this example model, Eco-indicator 99 is used to evaluate environmental impact. In the proposed lifecycle design optimisation method, the relationships among the product performance, the lifecycle cost and the lifecycle environmental impact are evaluated as a multi-objective optimisation problem. Analysis of the obtained Pareto optimum solution sets subsequently enables designers to pursue breakthrough product design solutions.
Active helicopter rotor control using blade-mounted actuators

An aeroelastic model of a smart rotor system (which incorporates blade-mounted trailing-edge flap actuators and conventional root pitch actuation) is presented in linear time invariant state space form. The servo-flap deflections are modeled as producing incremental lift and moment variations, so that any linear aerodynamic actuator can be evaluated. This smart rotor model is used to conduct parametric studies involving rotor blade torsional stiffness, center-of-gravity offset, additional actuator mass, and actuator placement. Results on the effects of collective root pitch and servo-flap actuation on rotor thrust response are presented. Active rotor vibration reduction is demonstrated by applying higher harmonic control algorithms to the state space rotor model. Using reasonable servo-flap deflections, a rotor equipped with trailing-edge flaps can provide enough authority to cancel higher harmonic vibration. Thesis Supervisor: Steven R. Hall, Sc.D. Title: Associate Professor of Aeronautics and Astronautics
Geospatial and Social Factors Influencing Morbidity due to Acute Infection in Pediatric Patients in Matiari, Rural Pakistan.

Infectious disease is the leading cause of mortality in children under five. This study has investigated environmental factors related to the morbidity of acute respiratory infections (ARIs), diarrhea, and growth using geographical information systems (GIS) technology. Anthropometric, address and disease prevalence data were collected through the SEEM study in Matiari, Pakistan. Publicly available map data was used to compile coordinates of healthcare facilities. A Pearson correlation coefficient (r) was used to calculate the correlation between distance from healthcare facilities and participant growth and morbidity. Other continuous variables influencing these outcomes were analyzed using a random forest regression model. In this study of 416 children, we found participants living closer to secondary hospitals had lower prevalence of ARI (r=0.154, p&lt;0.010) and diarrhea (r=0.228, p&lt;0.001) as well as participants living closer to Maternal Health Centers (MHCs): ARI (r=0.185, p&lt;0.002) and diarrhea (r=0.223, p&lt;0.001) compared to those living near primary facilities. Our random forest model showed distance to have high variable importance in the context of disease prevalence. Our results indicated that participants closer to more basic healthcare facilities reported a higher prevalence of both diarrhea and ARI than those near more urban facilities, highlighting potential public policy gaps in ameliorating rural health.
Use of different fixation times and application of two immunohistochemical methods for detection of KIT and Ki67 proteins in canine cutaneous mast cell tumors

ABSTRACT: Due to the high prevalence of mast cell tumors (MCTs) in the diagnostic routine, several factors, especially prognostic, have been sought to determine the biological behavior of these neoplasms. Immunohistochemistry (IHC) is one of the main tools utilized to biologically differentiate more aggressive tumors from less aggressive ones. However, some immunostainings are influenced by formalin fixation, interfering with the results. This is both a retrospective and prospective study of MCTs diagnosed in laboratory routine. A total of 25 samples, without knowledge about fixation time, were analyzed in the retrospective study, whereas 12 samples, with known fixation times, were assessed in the prospective study. Two histologic grading systems (Patnaik and Kiupel), special staining of toluidine blue, and IHC for KIT and Ki67 proteins were applied in both studies. Additionally, two amplification systems (biotinylated and non-biotinylated) for Ki67 protein and counting of the argyrophilic nucleolar organizing regions (AgNOR method) were tested in the prospective study. In the retrospective study, greater agreement between the evaluating pathologists was observed when the Kiupel system was used. IHC staining for KIT protein was effective in both studies, regardless of fixation time. IHC staining for Ki67 protein was highly sensitive to formaldehyde, and staining failure was observed in 56% of the cases in the retrospective study. In the prospective study, samples fixed for longer than 24 hours showed a reduction in the number of stained cells (altering the determination of the cell growth fraction) or showed absence of IHC staining in both amplification systems. The use of the AgNOR method to evaluate the rate of cell proliferation may be an alternative when the fixation time of the neoplasm is unknown or longer than 24 hours.
Accuracy Assessment of MODIS Land Aerosol Optical
Thickness Algorithms using AERONET Measurements

Abstract. The planned simultaneous availability of visible and near-IR observations from the geostationary platforms of Tropospheric Emissions: Monitoring of Pollution (TEMPO) and GOES R/S Advanced Base Imager (ABI) will present the opportunity of deriving an accurate aerosol product taking advantage of both ABI's high spatial resolution in the visible and TEMPO's sensitivity to aerosol absorption in the near-UV. Because ABI's spectral coverage is similar to that of MODIS, currently used MODIS aerosol algorithms can be applied to ABI observations. In this work, we evaluate existing MODIS algorithms of that derive aerosol optical thickness (AOT) over land surfaces using visible and near-IR observations. The Dark Target (DT), Deep Blue (DB), and Multiangle Implementation of Atmospheric Correction (MAIAC) algorithms are all applied to Aqua-MODIS radiance measurements. We have carried out an independent evaluation of each algorithm by comparing the retrieved AOT to space-time collocated ground-based sunphotometer measurements of the same parameter at 171 sites of the Aerosol Robotic Network (AERONET) over North America (NA). A spatiotemporal scheme co-locating the satellite retrievals with the ground-based measurements was applied consistently to all three retrieval datasets. We find that while the statistical performance of all three algorithms is comparable over darker surfaces over eastern NA, the MAIAC algorithm provides relatively better comparison over western NA sites characterized by inhomogeneous elevation and bright surfaces. MAIAC's finer product resolution (1 km), allows a substantially larger number of matchups than DB 10-km and DT 10-km (DT 3-km) products by 108 % and 125 % (83 %) respectively over Eastern NA, and by 144 % and 220 % (195 %) over Western NA. The characterization of error in AOT for the three aerosol products as a function of MAIAC-retrieved bi-directional surface reflectance shows a systematic positive bias in DT retrievals over brighter surfaces, whereas DB and MAIAC retrievals showed no such bias throughout the wide range of surface brightness with MAIAC offering lowest spread in errors. The results reported here represent an objective, unbiased evaluation of existing over-land aerosol retrieval algorithms of MODIS. The detailed statistical evaluation of the performance of each of these three algorithms may be used as guidance in the development of inversion schemes to derive aerosol properties from ABI or other MODIS-like sensors.