A Comparison of Cloud Layers from Ground and Satellite Active Remote Sensing at the Southern Great Plains ARM Site

Using the data collected over the Southern Great Plains ARM site from 2006 to 2010, the surface Active Remote Sensing of Cloud （ARSCL） and CloudSat-CALIPSO satellite （CC） retrievals of total cloud and six specified cloud types [low, midlow （ML）, high-mid-low （HML）, mid, high-mid （HM） and high] were compared in terms of cloud fraction （CF）, cloud-base height （CBH）, cloud-top height （CTH） and cloud thickness （CT）, on different temporal scales, to identify their respective advantages and limitations. Good agreement between the two methods was exhibited in the total CF. However, large discrepancies were found between the cloud distributions of the two methods at a high （240-m） vertical grid spacing. Compared to the satellites, ARSCL retrievals detected more boundary layer clouds, while they underestimated high clouds. In terms of the six specific cloud types, more low- and mid-level clouds but less HML- and high-level clouds were detected by ARSCL than by CC. In contrast, the ARSCL retrievals of ML- and HM-level clouds agreed more closely with the estimations from the CC product. Lower CBHs tended to be reported by the surface data for low-, ML- and HML-level clouds; however, higher CTHs were often recorded by the satellite product for HML-, HM- and high-level clouds. The mean CTs for low- and ML-level cloud were similar between the two products; however, the mean CTs for HML-, mid-, HM- and high-level clouds from ARSCL were smaller than those from CC.

THE ANALYSIS OF REMOTE SENSING IMAGES FOR ACTIVE FAULTS AND EARTHQUAKES IN CHINA

The Landsat image information has recently been widely applied to structural geology, especially to the analysis of lineaments, owing to their macroscopic, visual and comprehensive features. The images will be more effective when applied to the interpretation of active faults. Active faults are widely ditributed in China. Much attention has been paid to the study of active faults both in China and abroad. There is certain controversy concerning the implication of the term "active fault". Strictly speaking, the term should refer only to the faults that are still active in the present day. However, the term also usually refers to the faults which have been active continually or intermittently from the Quaternary (or the end of Tertiary) to the present day. We propose that the tones and the configurations of features on Landsat images are the principal keys to the interpretation of active faults. The faults, which display the most prominent

Advances in Research on Soil Moisture by Microwave Remote Sensing in China

Soil moisture is an important factor in global hydrologic circulation and plays a significant role in the research of hydrology, climatology, and agriculture. Microwave remote sensing is less limited by climate and time, and can measure in large scale. With these characteristics, this technique becomes an effective tool to measure soil moisture. Since the 1980s, Chinese researchers have investigated the soil moisture using microwave instruments. The active re- mote sensors are characteristic of high spatial resolution, thus with launch of a series of satellites, active microwave remote sensing of soil moisture will be emphasized. The passive microwave remote sensing of soil moisture has a long research history, and its retrieval algorithms were developed well, so it is an important tool to retrieve large scale moisture information from satellite data in the future.

Corchorus olitorius aqueous extract attenuates quorum sensing-regulated virulence factor production and biofilm formation

Objective:To investigate the effect of Corchorus olitorius aqueous fraction(COAF)on quorum sensing(QS)-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa(PAO1).Methods:The preliminary screening of the anti-QS effect of COAF was performed by evaluating the anti-pathogenic activity against Chromobacterium violaceum CV026 biosensor strain.Next,the inhibitory effects of COAF on QS-regulated pyocyanin production,proteolytic and elastolytic activities,swarming motility,and biofilm formation were evaluated in PAO1.Results:The results showed that the treatment of COAF significantly decreased the biofilm biomass,attenuated virulence factors,and inhibited swarming motility of PAO1 without affecting the growth of the bacteria in a dose-dependent manner.COAF at 2000μg/mL significantly decreased Las B elastase activity in PAO1 culture,exopolysaccharide production,swarming motility,pyocyanin level,and biomass of PAO1 by 55%(P<0.05),60%(P<0.01),61%(P<0.01),65%(P<0.01)and 73%(P<0.01),respectively.In addition,the production of violacein was decreased by 62%(P<0.01)with the treatment of a high dose of COAF.Conclusions:These findings indicate that COAF can be a potential source of anti-QS agents.

Techniques for DFB Fiber Laser Based Accelerometer

A distributed feedback fiber laser based Bragg grating vibration sensor system is proposed.Demodulated by using an unbalanced M-Z interferometer,experiment demonstrates that the system runs at a sensing sensitivity of about 257.2 rad·s2/m and a resolution of 4.2×10-5 m/s2 for monitoring acceleration.Experimental results show that the phase-shift changes with the acceleration linearly.

Development of piezoelectric-based technology for application in civil structural health monitoring

Piezoelectric material,as one of the great potential materials,had attracted lots of attention all over the world due to its distinguish advantages.In this paper,the development of piezoelectric-based technology for application in the field of civil structural health monitoring(CSHM),was summarized and discussed.Based on the different identification mechanisms,the piezoelectric transducer-based technology can be divided into two main approaches as the active or passive sensing and detection methods.This paper summarized the development of these two approaches and discussed their applications in the area of civil structural health monitoring,such as structural and concrete engineering,bridge engineering,pipeline engineering,protection engineering for geological hazards and earthquake disasters,and so on.In addition,the electrical mechanical impedance(EMI)technique,as one of the active identification methods,was also detailly presented.Finally,its great potential for the piezoelectric-based technique was presented based on the detail discussion,especially in the areas of civil structural health monitoring.

Privacy-preserving human activity sensing:A survey

With the prevalence of various sensors and smart devices in people’s daily lives,numerous types of information are being sensed.While using such information provides critical and convenient services,we are gradually exposing every piece of our behavior and activities.Researchers are aware of the privacy risks and have been working on preserving privacy while sensing human activities.This survey reviews existing studies on privacy-preserving human activity sensing.We first introduce the sensors and captured private information related to human activities.We then propose a taxonomy to structure the methods for preserving private information from two aspects:individual and collaborative activity sensing.For each of the two aspects,the methods are classified into three levels:signal,algorithm,and system.Finally,we discuss the open challenges and provide future directions.

Sensing cytochrome P4501A1 activity by a resorufin-based isoform-specific fluorescent probe

Cytochrome P4501 A1(CYP1A1),a heme-containing monooxygenase,is of particular importance for human health because of its vital roles in the metabolic activation of pro-carcinogenic compounds to the carcinogens.Deciphering the relevance of CYP1A1 to human diseases and screening of CYP1A1 modulators require reliable tool(s)for probing this key enzyme in complex biological matrices.Herein,a practical and ultrasensitive fluorescence-based assay for real-time sensing CYP1A1 activities in biological systems has been developed,via designing an isoform-specific fluorogenic sensor for CYP1A1(CHPO).The newly developed fluorogenic substrate for CYP1A1 has been carefully investigated in terms of specificity,sensitivity,precision,quantitative linear range and the anti-interference ability.The excellent selectivity,strong anti-interference ability and fast response kinetics,making the practicability of CHPObased CYP1A1 activity assay is better than that of most reported CYP1A1 activity assays.Furthermore,CHPO has been successfully used for imaging CYP1A1 activities in living cells and human tissues,as well as for high-throughput screening of CYP1A1 inhibitors using tissue preparations as enzyme sources.Collectively,this study provided a practical fluorogenic sensor for real-time sensing CYP1A1 in complex biological systems,which would strongly facilitate the investigations on the relevance of CYP1A1 to human diseases and promote high-throughput screening of CYP1A1 modulators for biomedical applications.

Sensorless Sensing with WiFi

Can WiFi signals be used for sensing purpose？ The growing PHY layer capabilities of WiFi has made it possible to reuse WiFi signals for both communication and sensing. Sensing via WiFi would enable remote sensing without wearable sensors, simultaneous perception and data transmission without extra communication infrastructure, and contactless sensing in privacy-preserving mode. Due to the popularity of WiFi devices and the ubiquitous deployment of WiFi networks, WiFi-based sensing networks, if fully connected, would potentially rank as one of the world＇s largest wireless sensor networks. Yet the concept of wireless and sensorless sensing is not the simple combination of WiFi and radar. It seeks breakthroughs from dedicated radar systems, and aims to balance between low cost and high accuracy, to meet the rising demand for pervasive environment perception in everyday life. Despite increasing research interest, wireless sensing is still in its infancy. Through introductions on basic principles and working prototypes, we review the feasibilities and limitations of wireless, sensorless, and contactless sensing via WiFi. We envision this article as a brief primer on wireless sensing for interested readers to explore this open and largely unexplored field and create next-generation wireless and mobile computing applications.

An Origami-Like Sheath of a Honeybee Tongue for Fluid Viscosity Sensing

Mechanoreceptors play a vital role for animals to sense and monitor environmental parameters,like flow speed,tactile resistance,and pressure.The hairy-structured trichoid sensillum,a common type of mechanoreceptor in insects,is generally non-motile,embedded in a socket connected with cuticular substrate.However,we discover that the trichoid sensilla on the tongue of western bees(Apis mellifera L.)is rotatable and can be actively maneuvered by bees.The trichoid sensilla together with the socket base are mounted on the origami-like sheath of the tongue,and can rotate outwards along with the deformation of the tongue sheath.We illustrate that the rotation of the tongue sensilla hairs can locally generate shear force in the liquid to sense the viscosity,which may facilitate bees to adjust their feeding strategies.The viscosity sensitivity of the rotatable trichoid sensilla based on the origami-like mechanism,according to our mechanical model,is 13 times greater than that of the fixed sensilla.In addition,our finite element analysis shows that strain would concentrate on the trichoid sensilla base when rotating in the liquid,which may structurally enhance its perception sensitivity.This study reports a new mechanism of active mechanoreceptors and may have implications for origami mechanisms with correlative functional components,especially for micro-robotic systems used in underwater viscosity sensing.

Water presence detection in a concrete crack using smart aggregates

Liquid migrating into existing concrete cracks is a serious problem for the reliability of concrete structures and can sometimes induce full concrete structural failures.In this paper,the authors present recent research on water presence detection in concrete cracks using piezoceramic-based smart aggregate(SA)transducers.The active sensing approach,in which one piezoceramic transducer is used to generate stress waves and others are used to detect the stress wave responses,is adopted in this research.Cracks formed in concrete structures act as stress reliefs,which attenuate the energy of the signals received by the SAs.In case of a crack being filled with liquid,which changes the wave impedance,the piezoceramic transducers will report higher received energy levels.A wavelet packet-based approach is developed to provide calculated energy values of the received signal.These different values can help detect the liquid presence in a concrete crack.A concrete beam specimen with three embedded SAs was fabricated and tested.Experimental results verified that the SA-based active sensing approach can detect a concrete crack and further detect the liquid presence in the concrete crack.

Wind turbine blade health monitoring with piezoceramic-based wireless sensor network

In this paper,a piezoceramic-based wireless sensor network(WSN)was developed for health monitoring of wind turbine blades with active sensing approach.The WSN system has an access point that coordinates the network and connects to a PC to control the wireless nodes.One wireless node functions as an actuator to excite an embedded piezoceramic patch with desired guided waves.The remaining wireless nodes function as sensors to detect and transmit the wave responses at distributed locations.The damage status inside the blade was evaluated through the analysis of the sensor signals.Based on wavelet packet analysis results,a damage index and a damage matrix were developed to evaluate the damage status at different locations.To verify the effectiveness of the proposed approach,a static loading test and a wind tunnel test were performed in the Laboratory of Joint Wind Tunnel and Wave Flume at Harbin Institute of Technology(HIT),China.Experimental results show that damage in wind turbine blades can be detected and evaluated by the proposed approach.

Effects of exogenous short-chain N-acyl homoserine lactone on denitrifying process of Paracoccus denitrificans

N-acyl-homoserine lactones（AHLs） serve as quorum-sensing signals, which control a number of bacterial processes in many proteobacteria. Here we report the effects of exogenous short-chain AHL on the denitrifying process of Paracoccus denitrificans, which are capable of aerobic and anaerobic growth by utilizing nitrate. The denitrification activity of these cells was monitored by measuring denitrification products（including nitrate, nitrite,and nitrous oxide）, and the individual messenger ribonucleic acid（m RNA） levels of nitrate,nitrite, nitric oxide and nitrous oxide reductases. The results indicated that 2 μmol/L C6-homoserine lactone（HSL） has little effect on cell density under either anaerobic or aerobic culture conditions, and the nitrate reduction activity appeared slightly affected by N-hexanoyl-DL-homoserine lactone（C6-HSL）. However, exogenous C6-HSL significantly affected the transcription of nitrite reductase and nitric oxide reductase genes in P.denitrificans regardless of the presence of oxygen, and N2O accumulation activity in P. denitrificans was suppressed by C6-HSL under aerobic condition. In contrast, exogenous C6-HSL stimulated the production of N2O under anaerobic condition, suggesting that the regulation of denitrification by quorum sensing may be important in N2O release.