Long-time Monitoring Research Articles

Monitoring investigation of solar diffuse fraction in Taiwan

Global solar radiation, which passes through the atmosphere and arrives on earth’s ground, is composed of two constituents, that is, beam and diffuse radiation. It is agreed that the beam radiation is the only effective part for use of solar energy in concentrating either photovoltaic or solar thermal energy application, which concentrates the incident sunlight to attain high performance of either electrical power or high-temperature thermal energy generation, respectively. Information of beam radiation quantity incident upon an absorbing surface is, thus, a prerequisite for the performance evaluation of concentrating optic device. However, very few data of diffuse fraction, defined as the ratio of diffuse radiation to global radiation, is available in Taiwan. A long-time monitoring investigation in the main island (Taiwan proper) and one offshore islet (Penghu) were conducted over recent years. It was found that the annually averaged diffuse fractions, calculated with the time duration from sunrise to sunset, in the east (Taitung) and west (Tainan) sides of the main island were about 0.49 and 0.53, respectively, while about 0.50 in the offshore islet (Penghu). Seasonal variations due to geographical/topographical effects on diffuse fraction are also reported and discussed. It is found that Northeast Monsoon has remarkable effects on increment of diffuse fraction in Taitung and Penghu, while insignificant effect in Tainan.

Indoor air quality analysis of residential buildings in northeast China based on field measurements and longtime monitoring

Outdoor air contamination was frequently observed and focused in northeast China in winter when severe cold days are common and understanding dynamic characteristics of indoor air quality in this area is essential for occupants' ventilation strategies. Herein, using spectrophotometric method, GC-MS (Gas Chromatography-Mass Spectrometer) method, TSI DustTrak particle tester and Telaire 7001 CO2 tester, we investigated the concentration change of formaldehyde (HCHO), volatile organic compounds (VOCs), PM2.5 and CO2 of 21 houses for 4 seasons under 2 conditions (airtight and natural ventilation). Moreover, 6 houses were selected to install convenient sensors for longtime monitoring. Outdoor temperature, concentration of PM2.5, residents' opening window behavior, indoor infiltration rate, temperature, relative humidity and the furniture surface area were also recorded for comparison and correlation analysis. According to the detected results, worst indoor conditions were revealed that average concentrations of HCHO (autumn), TVOC (summer), PM2.5 (winter) and CO2 (winter) were 0.094 mg/m3, 0.924 mg/m3, 0.073 mg/m3, and 883 ppm, respectively. Indoor concentration of PM2.5, TVOC and CO2 exceeded the standard limit and they changed with seasonal characteristics. The observed 4 factors have different effects on indoor air quality. Based on this research, it is recommended that outdoor condition be considered while opening and closing window in winter and ventilation be strengthened in summer.

(Invited) Low-Power Nanoscale Sensors for Low-Concentration Hydrogen Detection in Expired Air

Light-weight molecular sensors have attracted growing interests in recent years, since they have a potential to be used for easy, fast health condition check. Some molecules in breath are consider as markers of some diseases. For example, acetone is an indicator of diabetes mellitus. Nonanal is consider to be one of the biomarkers of lung cancer. If we can realize small-size and low-power sensors that detect a specific molecule selectively, the sensors will be integrated with mobile terminals such as smart phone and the concentration of several molecules in breath can be checked regularly for a long time of period. The long-time monitoring of changes in biomarker concentrations could enable extremely early-stage diagnosis of diseases. Therefore, the development of sensors to detect molecules in expired air is strongly demanded. In this work, we will introduce two type of nanoscale hydrogen sensors. One is nanoscale Pt film sensors that accurately detect the concentration of hydrogen even at high relative humidity. The other is suspended graphene sensor functionalized with Pd nanoparticles that can detect both hydrogen and water selectively depending on the bias voltage applied to the sensor. Hydrogen is an important biomarker for the human digestive system and its concentration ranges from sub-ppm to several-hundred ppm. However, accurate detection of ppm-level hydrogen in breath is difficult due to competing detection of water which is included in breath with high concentration. Here, we fabricated Pt thin films that respond to hydrogen in air at concentrations as low as 500 ppb [1]. In both dry and humid air, these films have almost identical response to hydrogen, i.e., their resistance decreases linearly with increasing hydrogen concentration regardless of relative humidity. Even at high relative humidity, these Pt thin films can detect ppm-level hydrogen. Based on the chemical kinetics, namely the adsorption and desorption of hydrogen and oxygen, the sensor response is quantitatively described by relating the hydrogen surface coverage to the magnitude of electron scattering at the Pt surface. The proposed model successfully reproduces the effects of hydrogen concentration and time on the sensitivity, particularly at hydrogen concentrations below 20 ppm. Another hydrogen sensor consisting of suspended graphene functionalized Pd nanoparticles will be also demonstrated. Various sensors using Pd as a sensing layer or as a catalyst of carbon materials have been proposed because Pd has selectivity to H2. However, most of them are affected by relative humidity variations. Therefore, high temperature operations for humidity robustness have been studied utilizing not only external heaters but also Joule heating (self-heating). However, most studies on self-heating focused on sensor response time and recovery time. No attention has been paid to self-heating-induced changes in the physical properties and device parameters except for temperature. Here, the effects of self-heating on Pd-functionalized suspended graphene sensors were investigated. Self-heating was realized by nanoscale point contacts between the graphene and Au electrodes, which suppressed heat dissipation to the electrodes. By applying an appropriate voltage bias, the graphene temperature was increased up to 180 °C. At temperatures over 100 °C, the sensor response realized by self-heating was lower than that by external heater heating. The response reduction was due to suppressed charged-carrier scatterings with H-induced potentials under high electric fields in the self-heated graphene. In addition, it should be noted that this sensor can detect hydrogen at high bias condition thanks to self-heating-induced high temperature and that it can detect water at low bias conditions because of easy adsorption of water on sensing materials. This multi-functionality of the sensors will be also promising for mobile applications where space availability is extremely limited. Reference [1] T. Tanaka et al., Sensors and Actuators B, 258, p913, 2018.

Radionuclide-fluorescence Reporter Gene Imaging to Track Tumor Progression in Rodent Tumor Models

Metastasis is responsible for most cancer deaths. Despite extensive research, the mechanistic understanding of the complex processes governing metastasis remains incomplete. In vivo models are paramount for metastasis research, but require refinement. Tracking spontaneous metastasis by non-invasive in vivo imaging is now possible, but remains challenging as it requires long-time observation and high sensitivity. We describe a longitudinal combined radionuclide and fluorescence whole-body in vivo imaging approach for tracking tumor progression and spontaneous metastasis. This reporter gene methodology employs the sodium iodide symporter (NIS) fused to a fluorescent protein (FP). Cancer cells are engineered to stably express NIS-FP followed by selection based on fluorescence-activated cell sorting. Corresponding tumor models are established in mice. NIS-FP expressing cancer cells are tracked non-invasively in vivo at the whole-body level by positron emission tomography (PET) using the NIS radiotracer [18F]BF4-. PET is currently the most sensitive in vivo imaging technology available at this scale and enables reliable and absolute quantification. Current methods either rely on large cohorts of animals that are euthanized for metastasis assessment at varying time points, or rely on barely quantifiable 2D imaging. The advantages of the described method are: (i) highly sensitive non-invasive in vivo 3D PET imaging and quantification, (ii) automated PET tracer production, (iii) a significant reduction in required animal numbers due to repeat imaging options, (iv) the acquisition of paired data from subsequent imaging sessions providing better statistical data, and (v) the intrinsic option for ex vivo confirmation of cancer cells in tissues by fluorescence microscopy or cytometry. In this protocol, we describe all steps required for routine NIS-FP-afforded non-invasive in vivo cancer cell tracking using PET/CT and ex vivo confirmation of in vivo results. This protocol has applications beyond cancer research whenever in vivo localization, expansion and long-time monitoring of a cell population is of interest.

Radionuclide-fluorescence Reporter Gene Imaging to Track Tumor Progression in Rodent Tumor Models.

Metastasis is responsible for most cancer deaths. Despite extensive research, the mechanistic understanding of the complex processes governing metastasis remains incomplete. In vivo models are paramount for metastasis research, but require refinement. Tracking spontaneous metastasis by non-invasive in vivo imaging is now possible, but remains challenging as it requires long-time observation and high sensitivity. We describe a longitudinal combined radionuclide and fluorescence whole-body in vivo imaging approach for tracking tumor progression and spontaneous metastasis. This reporter gene methodology employs the sodium iodide symporter (NIS) fused to a fluorescent protein (FP). Cancer cells are engineered to stably express NIS-FP followed by selection based on fluorescence-activated cell sorting. Corresponding tumor models are established in mice. NIS-FP expressing cancer cells are tracked non-invasively in vivo at the whole-body level by positron emission tomography (PET) using the NIS radiotracer [18F]BF4-. PET is currently the most sensitive in vivo imaging technology available at this scale and enables reliable and absolute quantification. Current methods either rely on large cohorts of animals that are euthanized for metastasis assessment at varying time points, or rely on barely quantifiable 2D imaging. The advantages of the described method are: (i) highly sensitive non-invasive in vivo 3D PET imaging and quantification, (ii) automated PET tracer production, (iii) a significant reduction in required animal numbers due to repeat imaging options, (iv) the acquisition of paired data from subsequent imaging sessions providing better statistical data, and (v) the intrinsic option for ex vivo confirmation of cancer cells in tissues by fluorescence microscopy or cytometry. In this protocol, we describe all steps required for routine NIS-FP-afforded non-invasive in vivo cancer cell tracking using PET/CT and ex vivo confirmation of in vivo results. This protocol has applications beyond cancer research whenever in vivo localization, expansion and long-time monitoring of a cell population is of interest.

Calculation and Analysis on the Soft Soil Foundation Settlement with Elastic-Visco-Plasticity (EVP) Model

The EVP model is an available method to apply to the vertical settlement of soft soil consolidation calculation and analysis. Compared with Visco-Plasticity model, it shows more consistent with the actual stress conditions of the soil. In this paper, We have extracted soil samples in BinHai garden for assay. Then through the comparison with calculating results and a long-time engineering monitoring in BinHai garden soft soil area, a feasibility EVP model study on the vertical settlement in soft soil area is peoposed. Further a consequent sedimentation forecast was made according with the EVP model calculation. In the end, the settlement influence from creep was analyzed through one-dimensional consolidation theory.

Cross-layer design for reducing delay and maximizing lifetime in industrial wireless sensor networks

Low delay and long lifetime are a very important issue for industrial wireless sensor networks (IWSNs) in which it require long-time monitoring of industrial sites and respond quickly to events that is monitored; therefore, high delay communications can cause serious damage to property and personnel at industrial field. Due to delay, lifetime, and other performance involved to multiple layers, it is difficult to optimize from a single layer. Therefore, a cross-layer design optimal scheme for reducing delay and maximizing lifetime (RDML) scheme is proposed for IWSNs which is from several layers such as transmitted power, duty cycle, and node deployment positions to optimize the network performance of delay and lifetime etc. Firstly, due to the node which sends a packet within a cycle, different duty cycle leads to different selection of the modulation level, resulting in different power consumption efficiency of transmitting data. Through careful analysis, the optimal value of the duty cycle is given which has the lowest energy consumption per bit. In fact, the energy consumption of the node is not balanced. Therefore, an optimization method of changing the duty cycle is proposed. In this paper, larger duty cycle is chosen for nodes with residual energy to improve the reliability of data transmission, reducing the probability of data retransmission, so that the network delay can be reduced in IWSNs. Third, based on the previous analysis, a network optimization deployment algorithm is proposed, which not only maximizes the energy efficiency of a single node but also maximizes the network lifetime and the total network energy efficiency. Both our comprehensive theoretical analysis results indicate that the performance of RDML scheme is better than the previous studies. Relative to equal distance and optimal duty cycle scheme, the RDML scheme can reduce the delay by 19–30% and increase the lifetime by more than 43%.

Extraction and recognition of attractors in three-dimensional Lorenz plot

Lorenz plot (LP) method which gives a global view of long-time electrocardiogram signals, is an efficient simple visualization tool to analyze cardiac arrhythmias, and the morphologies and positions of the extracted attractors may reveal the underlying mechanisms of the onset and termination of arrhythmias. But automatic diagnosis is still impossible because it is lack of the method of extracting attractors by now. We presented here a methodology of attractor extraction and recognition based upon homogeneously statistical properties of the location parameters of scatter points in three dimensional LP (3DLP), which was constructed by three successive RR intervals as X, Y and Z axis in Cartesian coordinate system. Validation experiments were tested in a group of RR-interval time series and tags data with frequent unifocal premature complexes exported from a 24-hour Holter system. The results showed that this method had excellent effective not only on extraction of attractors, but also on automatic recognition of attractors by the location parameters such as the azimuth of the points peak frequency ( A PF ) of eccentric attractors once stereographic projection of 3DLP along the space diagonal. Besides, A PF was still a powerful index of differential diagnosis of atrial and ventricular extrasystole. Additional experiments proved that this method was also available on several other arrhythmias. Moreover, there were extremely relevant relationships between 3DLP and two dimensional LPs which indicate any conventional achievement of LPs could be implanted into 3DLP. It would have a broad application prospect to integrate this method into conventional long-time electrocardiogram monitoring and analysis system.

Assessment of temporary cerebral effects induced by focused ultrasound with optical coherence tomography angiography.

Focused ultrasound (FUS) in combination with microbubbles temporally and locally increases the permeability of the blood-brain barrier (BBB) for facilitating drug delivery. However, the temporary effects of FUS on the brain microstructure and microcirculation need to be addressed. We used label-free optical coherence tomography (OCT) and OCT angiography (OCTA) to investigate the morphological and microcirculation changes in mouse brains due to FUS exposure at different power levels. Additionally, the recovery progress of the induced effects was studied. The results show that FUS exposure causes cerebral vessel dilation and can be identified and quantitatively analyzed via OCT/OCTA. Micro-hemorrhages can be detected when an excessive FUS exposure power is applied, causing the degradation of OCTA signal owing to strong scattering by leaked red blood cells (RBCs) and weaker backscattered intensity from RBCs in vessels. The vessel dilation effect due to FUS exposure was found to abate in several hours. This study demonstrates that the FUS-induced cerebral transiently dilated effects can be in-vivo differentiated and monitored with OCTA, and shows the feasibility of using OCT/OCTA as a novel tool for long-time monitoring of cerebral vascular dynamics during FUS-BBB opening process.

Long-time resistivity monitoring of a freshwater/saltwater transition zone using the vertical electrode system SAMOS

In September 2009 two newly developed vertical electrode systems were installed in boreholes in the water catchment areas Waterdelle and Ostland at the North Sea island Borkum to monitor possible changes of the transition zone between the freshwater lens and the underlying saltwater. The vertical electrode systems, which were both installed between 44 m and 65 m below ground level, are used for geoelectrical multi-electrode measurements carried out automatically several times per day; the measurements are still ongoing. The whole system consisting of a vertical electrode system in a borehole and the measuring unit at ground level is called SAMOS (Saltwater Monitoring System).At both locations the data show a clear resistivity decrease that indicates the transition zone between freshwater and saltwater. The depth of the transition zone as well as the kind of resistivity decrease is very stable since 2010.Temporal changes are visible if single depths are considered. In 2015 Miriam Ibenthal used a vertical 2D density-dependent groundwater flow model to explain the long-term resistivity measurements and showed that the temporal changes at CLIWAT 2 (Ostland) could be explained by variations of the groundwater level, changing groundwater recharge rates and changing pumping rates of the nearby located drinking water supply wells.

Sports Injuries: Diagnosis, Prevention, Stem Cell Therapy, and Medical Sport Strategy.

Sports injuries diagnosis, prevention, and treatment are the most important issues of sports medicine. Fortunately, sports injuries are often treated effectively, and people with damage recover and return to the sport in a satisfactory condition. Meanwhile, many sports injuries and complications can be prevented. In general, sports injuries include acute or chronic injuries. Given increasing in popularity, sports medicine doctors use stem cells to treat a wide variety of sports injuries, including damage to tendons, ligaments, muscles, and cartilage. Stem cell therapy to an injured area could be done through direct surgical application, stem-cell-bearing sutures, and injection. Stem cell therapy holds potential for repair and functional plasticity following sports injuries compared to traditional methods; however, the mechanism of stem cell therapy for sports injuries remains largely unknown. Medical imaging technologies provide the hope to ample the knowledge concerning basic stem cell biology in real time when transplanted into sport-induced damaged organs. Using stem cell treatment might restore continuity and regeneration and promote growth back the organ targets. Besides, using a noninvasive medical imaging method would have the long-time monitoring advantage to the stem cells transplanting individual. The multimodality imaging technique allows for studying acute pathological events following sports injuries; therefore, the use of imaging techniques in medicine permits the straight examination of dynamic regenerative events of specific stem cells following a sports injury in people.

Neonatal EEG- an overview

Electro-encephalogram (EEG) is the best non-invasive modality for brain monitoring. As brain continues to develop and mature in neonatal period, EEG of a normal newborn varies from time to time. Wave patterns may be normal at one developmental stage and abnormal at another stage. There are many types of EEG waves like alpha, beta, gamma & delta waves. Burst suppression occurs in very sick neonates following brain damage due to asphyxia & predicts poor prognosis. Isoelectric pattern occurs in severe asphyxia, circulatory collapse, massive intracerebral hemorrhage, severe inborn metabolic deficits, CNS bacterial or viral infections, drug-induced state, hypothermia, postictal recording and in malformations like hydranencephaly or massive hydrocephalus. Grading of severity of disease condition can be done based on EEG. They can be vital in arriving etiological diagnosis. EEG distinguishes between normal paroxysmal movements from epileptic seizures. Nearly 90% of abnormal movements mimiking seizures may be nonepileptic after EEG study. Early recordings, prolonged recordings at different activity states, serial short interval EEGs increase the prognostic value of EEGs. Long-time bedside monitoring of brain function can be done by amplitude-integrated EEG (aEEG). Some rare neonatal epilepsy syndromes have characteristic EEG features. Artifacts mimicking electrical seizures include environmental interference, electrode impedence abnormalities, motion artifacts and endogenous non-cerebral potentials which can be distinguished by Polygraphy. Drugs can alter background activity. EEG is a boon for noninvasive bedside continuous monitoring of the brain. Judicious application of this technique can help in prompt management of various pathologies like seizures , encephalopathies, epilepsy and asphyxia.

Statistical pattern recognition approach for long-time monitoring of the G.Meazza stadium by means of AR models and PCA

In recent years, the interest for the automatic evaluation of the state of civil structures is increased. The development of Structural Health Monitoring is allowed by the low costs of the hardware and the improving of the computational capacity of computers that can analyze considerable amount of data in short time. A Structural Health Monitoring (SHM) system should continuously monitor structures, extracting and processing relevant information, to efficiently allocate the resources for maintenance and ensure the security of the structure. Considering the latest developments in this field, great attention has been paid to data-based approaches, especially to autoregressive models; these econometric models, born in the field of finance, are usually used to analyze the vibration time series provided by the sensors applied on the monitored structures. Indexes based on these autoregressive models can be used as features by which the structural integrity can be assessed. This work proposes the application of a multivariable analysis, Principal Component Analysis (PCA), to the set of the autoregressive model parameters estimated on the vibration responses of a real structure under operational conditions. This approach reduces a complex set of data to a lower dimension, by representing the behavior of the structure through the few variables. This work uses the principal components of the autoregressive model parameters as indicators that can effectively describe different operational levels and some important environmental effects. The strategy is applied for the first time on the data collected by the long-time monitoring system installed on the stands of the G. Meazza stadium in Milan. The results will show that this procedure is effective in representing the status of the structure and can be used in a structural health monitoring prospective.

The operation modal analysis of the structure crack fault diagnosis based on pseudo-successive data

In order to monitor the crack propagation of the structure in the working state for a long time, an operation modal analysis method based on pseudo-successive data is proposed. The vibration response signals of the cantilever beam under white noise excitation are collected and the modal parameters are extracted by the time-frequency operation modal analysis method based on the complex Morlet wavelet. In comparison with the experimental modal analysis results of hammering method, it is revealed that the error of the time-frequency operation modal analysis method is less than 10 %. By setting cracks of different lengths on the cantilever beam, the vibration response signals are extracted, and the modal parameters are extracted by the operation modal analysis method separately. By comparing those modal parameters above, it is found that the natural frequencies of the second, the fourth and the sixth orders decrease with the increase of the crack depth, and the changes of natural frequencies show the monotonicity. So, it can be used as an index for quantitative identification of crack damage. The pseudo continuous data monitoring signals of crack propagation can be constructed by means of “first discrete, then continuous”. The modal parameters changes of the whole crack propagation can be observed in one time plane by means of the operation modal analysis method. Therefore, the effective monitoring and diagnosis of the structure can be completed in case of excessive data of long-time vibration monitoring signals.

High-speed video capillaroscopy method for imaging and evaluation of moving red blood cells

The video capillaroscopy system with high image recording rate to resolve moving red blood cells with velocity up to 5 mm/s into a capillary is considered. Proposed procedures of the recorded video sequence processing allow evaluating spatial capillary area, capillary diameter and central line with high accuracy and reliability independently on properties of individual capillary. Two-dimensional inter frame procedure is applied to find lateral shift of neighbor images in the blood flow area with moving red blood cells and to measure directly the blood flow velocity along a capillary central line. The developed method opens new opportunities for biomedical diagnostics, particularly, due to long-time continuous monitoring of red blood cells velocity into capillary. Spatio-temporal representation of capillary blood flow is considered. Experimental results of direct measurement of blood flow velocity into separate capillary as well as capillary net are presented and discussed.

Nonmediated, Label-Free Based Detection of Cardiovascular Biomarker in a Biological Sample.

Direct electrochemical (EC) monitoring in a cell culture medium without electron transporter as called mediator is attractive topic in vitro organoid based on chip with frequently and long-time monitoring since it can avoid to its disadvantage as stability, toxicity. Here, direct monitoring with nonmediator is demonstrated based on impedance spectroscopy under the culture medium in order to overcome the limitation of mediator. The applicability of EC monitoring is shown by detecting alpha-1-anti trypsin (A1AT) which is known as biomarkers for cardiac damage and is widely chosen in organoid cardiac cell-based chip. The validity of presented EC monitoring is proved by observing signal processing and transduction in medium, mediator, medium-mediator complex. After the observation of electron behavior, A1AT as target analyte is immobilized on the electrode and detected using antibody-antigen interaction. As a result, the result indicates limit of detection is 10 ng mL-1 and linearity for the 10-1000 ng mL-1 range, with a sensitivity of 3980 nF (log [g mL])-1 retaining specificity. This EC monitoring is based on label-free and reagentless detection, will pave the way to use for continuous and simple monitoring of in vitro organoid platform.

High-Efficiency Cell-Penetrating Helical Poly(phenyl isocyanide) Chains Modified Cellular Tracer and Nanovectors with Thiol Ratiometric Fluorescence Imaging Performance

In order to precisely tail the endocytosis process and determine the internal location of drug carriers in cells, fluorescent tracers with high sensitivity and versatility are one of the most powerful tools. Nevertheless, conventional single fluorescent probes always suffered from the interference of background fluorescence or the lack of long-time monitoring capability, resulting in the low resolution and efficiency. To overcome this drawback, nanocarriers capable of multicolor fluorogenic and ratiometric properties became an urgently needed solution. In this contribution, starting from pentafluorophenyl ester (PFP)- and tetraphenylethene (TPE)-functionalized phenyl isocyanide (PI) monomers as well as l-hydrophilic (HP) PI monomers, a type of well-defined amphiphilic block copolymer, P(PFPPI-co-TPEPI-co-HPPI)-b-HPPPI, with controlled molecular weights and tunable compositions was prepared through sequential living copolymerization with phenylethynyl Pd(II) complex as a single catalyst in one pot. Disulfi...

Monitoring the impact of fugitive CO2 emissions on wheat growth in CCS-EOR areas using satellite and field data

In-situ monitoring of the environmental impact is essential for the verification of clean operation of carbon capture and storage (CCS) projects. We conducted an empirical study based on remotely sensed data and field observations from an enhanced oil recovery (EOR) site in China. Geostatistical analysis and general linear model regression were performed to detect the impact of fugitive CO2 emission from oil buffer tanks. Results show that the emitted CO2 resulted in CO2 enrichment about 25–100 m away from the buffer tanks. The spatial pattern and semivariogram parameters of normalized differential vegetation index (NDVI) in the CCS core operating area had not been altered significantly. The CO2 concentration is not a statistically significant explanatory factor for the variation of wheat growth in the present CCS-EOR site that located in Gaoqing County in the east of China. The impact of fugitive CO2 emission on wheat growth appears limited because of the instability and rapid diffusion of emitted CO2. However, we emphasize that these results were extracted from the in-situ monitoring that characterized by macro-level and short term. Long-term biology-based study at a micro-level is imperative for further understanding and determining the environmental impact of fugitive CO2 emission. Moreover, considering the incidental CO2 breakthrough and the unknown impact of emitted gas, including CO2 and hydrocarbons, on the quality of wheat plant and grain, long-time field monitoring, and improvement of production equipment and technique are essential to ensure the clean production of CCS-EOR.

A microneedle electrode array on flexible substrate for long-term EEG monitoring

Conventional wet electrodes require skin preparation and gel usage to maintain low interface impedance, which limit their applications in long-term monitoring of biopotentials such as electroencephalogram (EEG). To address this problem, microneedle electrode arrays (MNEAs) have been employed as dry electrodes, which could be capable of EEG monitoring without skin abrasion and gel electrolyte. However, most of them are usually based on rigid substrates that are not conformal to curved and moved human skin. Therefore, we develop a flexible parylene-based MNEA (P-MNEA) with silicon microneedles, which could provide not only conformal but also robust contact. Firstly, the microfabrication process is concretely illustrated and makes it repeatable. Then, penetration tests illustrate these microneedles are robust enough to penetrate into epidermis so that impedances of stratum corneum make limited contribution to interface impedance. Consequently, in vivo impedance results verify the priority of P-MNEA in long-time impedance stability. Meanwhile, competitive impedance density of 7.5KΩcm2@10Hz is attained. Eventually, EEG recoding results as well as correlation and coherence analyses of P-MNEA indicate comparable performance to that of wet electrode. In brief, these results reveal promising prospect of P-MNEA in long-time EEG monitoring.

Long-time monitoring of the G. Meazza stadium in a pattern recognition prospective

In recent years, the interest for the automatic evaluation of the state of civil structures is increased. The development of Structural Health Monitoring is allowed by the low costs of the hardware and the increasing of the computational capacity of computers that can analyze considerable amount of data in short time. A Structural Health Monitoring (SHM) system should continuously monitor structures, extracting and processing relevant information, in order to efficiently allocate the resources for maintenance and ensure the security of the structure. Considering the latest developments in this field, great attention has been paid to data-based approaches, especially to autoregressive models; these econometric models, born in the field of finance, are usually used to analyze the vibration time series provided by the sensors applied on the monitored structures. Indexes based on these autoregressive models can be used as features by which the structural integrity can be assessed. This work proposes the application of multivariable analysis, the Principal Component Analysis (PCA), to the parameters of autoregressive models estimated on the vibration responses of a real structure under operational conditions. This approach reduces a complex set of data to a lower dimension, by representing the behavior of the structure through the few variables. This work uses the principal components of the autoregressive model parameters as indicators that can effectively describe some important environmental effects. The strategy is applied for the first time on the data collected by the long-time monitoring system installed on the stands of the G. Meazza stadium in Milan. The results will show that this procedure is effective in representing the status of the structure and can be used in a structural health monitoring prospective.