bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Potential Distribution and Carbon Dynamics of Natural Terrestrial Ecosystems: A Case Study of Turkey
Authors: Evrendilek Fatih , Berberoglu Suha , Gulbeyaz Onder , Ertekin Can
Published: October 2008

We derived a simple model that relates the classification of biogeoclimatezones, (co)existence and fractional coverage of plant functional types (PFTs), and patternsof ecosystem carbon (C) stocks to long-term average values of biogeoclimatic indices in atime- and space-varying fashion from climate–vegetation equilibrium models. ProposedDynamic Ecosystem Classification and Productivity (DECP) model is based on the spatialinterpolation of annual biogeoclimatic variables through multiple linear regression (MLR)models and inverse distance weighting (IDW) and was applied to the entire Turkey of780,595 km2 on a 500 m x 500 m grid resolution. Estimated total net primary production(TNPP) values of mutually exclusive PFTs ranged from 108 26 to 891 207 Tg C yr-1under the optimal conditions and from 16 7 to 58 23 Tg C yr-1 under the growth-limiting conditions for all the natural ecosystems in Turkey. Total NPP values ofcoexisting PFTs ranged from 178 36 to 1231 253 Tg C yr-1 under the optimalconditions and from 23 8 to 92 31 Tg C yr-1 under the growth-limiting conditions. Thenational steady state soil organic carbon (SOC) storage in the surface one meter of soil wasestimated to range from 7.5 1.8 to 36.7 7.8 Pg C yr-1 under the optimal conditions andfrom 1.3 0.7 to 5.8 2.6 Pg C yr-1 under the limiting conditions, with the national range of 1.3 to 36.7 Pg C elucidating 0.1% and 2.8% of the global SOC value (1272.4 Pg C), respectively. Our comparisons with literature compilations indicate that estimated patterns of biogeoclimate zones, PFTs, TNPP and SOC storage by the DECP model agree reasonably well with measurements from field and remotely sensed data.
Impact of Climate Change on Irrigation Demand and Crop Growth in a Mediterranean Environment of Turkey
Authors: Yano Tomohisa , Aydin Mehmet , Haraguchi Tomokazu
Published: October 2008

A simulation study was carried out to describe effects of climate change on cropgrowth and irrigation water demand for a wheat-maize cropping sequence in aMediterranean environment of Turkey. Climate change scenarios were projected using dataof the three general circulation models—GCMs (CGCM2, ECHAM4 and MRI)—for theperiod of 1990 to 2100 and one regional climate model—RCM—for the period of 2070 to2079. Potential impacts of climate change based on GCMs data were estimated for the A2scenario in the Special Report on Emission Scenarios (SRES). The forcing data for theboundary condition of the RCM were given by the MRI model. Daily CGCM2 and RCMdata were used for computations of water balance and crop development. Predictionsderived from the models about changes in irrigation and crop growth in this study coveredthe period of 2070 to 2079 relative to the baseline period of 1994 to 2003. The effects ofclimate change on water demand and on wheat and maize yields were predicted using thedetailed crop growth subroutine of the SWAP (Soil-Water-Atmosphere-Plant) model. Precipitation was projected to decrease by about 163, 163 and 105 mm during the periodof 1990 to 2100 under the A2 scenario of the CGCM2, ECHAM4 and MRI models,respectively. The CGCM2, ECHAM4 and MRI models projected a temperature rise of 4.3,5.3 and 3.1 oC, respectively by 2100. An increase in temperature may result in a higherevaporative demand of the atmosphere. However, actual evapotranspiration (ETa) fromwheat cropland under a doubling CO2 concentration for the period of 2070 to 2079 wasSensors 2007, 7 2298 predicted to decrease by about 28 and 8% relative to the baseline period based on the CGCM2 and RCM data, respectively. According to these models, irrigation demand by wheat would be higher for the same period due to a decrease in precipitation. Both ETa and irrigation water for maize cropland were projected to decrease by 24 and 15% according to the CGCM2, and 28 and 22% according to the RCM, respectively. The temperature rise accelerated crop development but shortened the growing period by 24 days for wheat and 9 days for maize according to the CGCM2 data. The shortened growth duration with a higher temperature reduced the biomass accumulation of both crops regardless of CO2-fertilization effect. With the combined effect of CO2-fertilization and increased temperature, the CGCM2 and RCM projections resulted in an increase by 16 and 36% in grain yield of wheat and a decrease by about 25% and an increase by 3% in maize yield, respectively.
Non-invasive Optical Biosensor for Probing Cell Signaling
Authors: Fang Ye
Published: October 2008

Cell signaling mediated through a cellular target is encoded by spatial andtemporal dynamics of downstream signaling networks. The coupling of temporal dynamicswith spatial gradients of signaling activities guides cellular responses upon stimulation.Monitoring the integration of cell signaling in real time, if realized, would provide a newdimension for understanding cell biology and physiology. Optical biosensors includingresonant waveguide grating (RWG) biosensor manifest a physiologically relevant andintegrated cellular response related to dynamic redistribution of cellular matters, thusproviding a non-invasive means for cell signaling study. This paper reviews recentprogresses in biosensor instrumentation, and theoretical considerations and potentialapplications of optical biosensors for whole cell sensing.
Effect of Estimated Daily Global Solar Radiation Data on the Results of Crop Growth Models
Authors: Trnka Miroslav , Eitzinger Josef , Kapler Pavel , Dubrovský Martin , Semerádová Daniela , Žalud Zdeněk , Formayer Herbert
Published: October 2008

The results of previous studies have suggested that estimated daily globalradiation (RG) values contain an error that could compromise the precision of subsequentcrop model applications. The following study presents a detailed site and spatial analysis ofthe RG error propagation in CERES and WOFOST crop growth models in Central Europeanclimate conditions. The research was conducted i) at the eight individual sites in Austria andthe Czech Republic where measured daily RG values were available as a reference, withseven methods for RG estimation being tested, and ii) for the agricultural areas of the CzechRepublic using daily data from 52 weather stations, with five RG estimation methods. In thelatter case the RG values estimated from the hours of sunshine using the ångström-Prescottformula were used as the standard method because of the lack of measured RG data. At thesite level we found that even the use of methods based on hours of sunshine, which showedthe lowest bias in RG estimates, led to a significant distortion of the key crop model outputs.When the ångström-Prescott method was used to estimate RG, for example, deviationsgreater than ±10 per cent in winter wheat and spring barley yields were noted in 5 to 6 percent of cases. The precision of the yield estimates and other crop model outputs was lowerwhen RG estimates based on the diurnal temperature range and cloud cover were used (mean bias error 2.0 to 4.1 per cent). The methods for estimating RG from the diurnal temperature range produced a wheat yield bias of more than 25 per cent in 12 to 16 per cent of the seasons. Such uncertainty in the crop model outputs makes the reliability of any seasonal yield forecasts or climate change impact assessments questionable if they are based on this type of data. The spatial assessment of the RG data uncertainty propagation over the winter wheat yields also revealed significant differences within the study area. We found that RG estimates based on diurnal temperature range or its combination with daily total precipitation produced a bias of to 30 per cent in the mean winter wheat grain yields in some regions compared with simulations in which RG values had been estimated using the ångström-Prescott formula. In contrast to the results at the individual sites, the methods based on the diurnal temperature range in combination with daily precipitation totals showed significantly poorer performance than the methods based on the diurnal temperature range only. This was due to the marked increase in the bias in RG estimates with altitude, longitude or latitude of given region. These findings in our view should act as an incentive for further research to develop more precise and generally applicable methods for estimating daily RG based more on the underlying physical principles and/or the remote sensing approach.
An Electronic Measurement Instrumentation of the Impedance of a Loaded Fuel Cell or Battery
Authors: Aglzim El-Hassane , Rouane Amar , El-Moznine Reddad
Published: October 2008

In this paper we present an inexpensive electronic measurement instrumentationdeveloped in our laboratory, to measure and plot the impedance of a loaded fuel cell orbattery. Impedance measurements were taken by using the load modulation method. Thisinstrumentation has been developed around a VXI system stand which controls electroniccards. Software under Hpvee® was developed for automatic measurements and the layout ofthe impedance of the fuel cell on load. The measurement environment, like the ambienttemperature, the fuel cell temperature, the level of the hydrogen, etc..., were taken withseveral sensors that enable us to control the measurement. To filter the noise and theinfluence of the 50Hz, we have implemented a synchronous detection which filters in a verynarrow way around the useful signal. The theoretical result obtained by a simulation underPspice® of the method used consolidates the choice of this method and the possibility ofobtaining correct and exploitable results. The experimental results are preliminary results ona 12V vehicle battery, having an inrush current of 330A and a capacity of 40Ah (impedancemeasurements on a fuel cell are in progress, and will be the subject of a forthcoming paper).The results were plotted at various nominal voltages of the battery (12.7V, 10V, 8V and 5V)and with two imposed currents (0.6A and 4A). The Nyquist diagram resulting from theexperimental data enable us to show an influence of the load of the battery on its internalimpedance. The similitude in the graph form and in order of magnitude of the valuesobtained (both theoretical and practical) enables us to validate our electronic measurementinstrumentation. One of the future uses for this instrumentation is to integrate it with several control sensors, on a vehicle as an embedded system to monitor the degradation of fuel cell membranes.
Development of QCM Trimethylamine Sensor Based on Water Soluble Polyaniline
Authors: Li Guang , Zheng Junbao , Ma Xingfa , Sun Yu , Fu Jun , Wu Gang
Published: October 2008

A rapid, sensitive, low-cost device to detect trimethylamine was presented in thispaper. The preparation of water soluble polyaniline was firstly studied. Then the polyanilinewas characterized via Fourier transform infrared spectroscopy (FTIR), UV-visiblespectroscopy and scanning electron microscopy (SEM). Based on the water solublepolyaniline film, a quartz crystal microbalance (QCM) sensor for trimethylamine detectionwas fabricated and its characteristics were examined. The sensor consisted of one quartzcrystal oscillator coated with the polyaniline film for sensing and the other one forreference. Pretreated with trimethylamine, the QCM sensor had an excellent linearsensitivity to trimethylamine. Easily recovered by N2 purgation, the response of the sensorexhibited a good repeatability. Responses of the sensor to trimethylamine, ethanol and ethylacetate were compared, and the results showed that the response was related to the polarityof the analyte vapor. Experimental result also showed that the sensitivity of the sensor wasrelatively stable within one month. The simple and feasible method to prepare and coat thepolyaniline sensing film makes it promising for mass production.
A MEMS-based Air Flow Sensor with a Free-standing Micro-cantilever Structure
Authors: Wang Yu-Hsiang , Lee Chia-Yen , Chiang Che-Ming
Published: October 2008

This paper presents a micro-scale air flow sensor based on a free-standingcantilever structure. In the fabrication process, MEMS techniques are used to deposit asilicon nitride layer on a silicon wafer. A platinum layer is deposited on the silicon nitridelayer to form a piezoresistor, and the resulting structure is then etched to create afreestanding micro-cantilever. When an air flow passes over the surface of the cantileverbeam, the beam deflects in the downward direction, resulting in a small variation in theresistance of the piezoelectric layer. The air flow velocity is determined by measuring thechange in resistance using an external LCR meter. The experimental results indicate that theflow sensor has a high sensitivity (0.0284 ω/ms-1), a high velocity measurement limit (45ms-1) and a rapid response time (0.53 s).
Utilizing of Square Wave Voltammetry to Detect Flavonoids in the Presence of Human Urine
Authors: Adam Vojtech , Mikelova Radka , Hubalek Jaromír , Hanustiak Pavel , Beklova Miroslava , Hodek Petr , Horna Ales , Trnkova Libuse , Stiborova Marie , Zeman Ladislav , Kizek Rene
Published: October 2008

About biological affecting of flavonoids on animal organisms is known less,thus we selected flavonoids, flavanones and flavones, and their glycosides, which wereexamined as potential inducers of cytochrome(s) P450 when administrated by gavages intoexperimental male rats. The study was focused on induction of CYP1A1, the majorcytochrome P450 involved in carcinogen activation. The data obtained demonstrate thenecessity of taking into account not only ability of flavonoids to bind to Ah receptor(induction factor) but also to concentrate on their distribution and metabolism (includingcolon microflora) in the body. After that we examined certain flavonoids as potential inducers of cytochrome P450, we wanted to suggest and optimize suitable electrochemical technique for determination of selected flavonoids (quercetin, quercitrin, rutin, chrysin and diosmin) in body liquids. For these purposes, we selected square wave voltannetry using carbon paste electrode. Primarily we aimed on investigation of their basic electrochemical behaviour. After that we have optimized frequency, step potential and supporting electrolyte. Based on the results obtained, we selected the most suitable conditions for determination of the flavonoids as follows: frequency 180 Hz, step potential 1.95 mV/s and phosphate buffer of pH 7 as supporting electrolyte. Detection limits (3 S/N) of the flavonoids were from units to tens of nM except diosmin, where the limit were higher than μM. In addition, we attempted to suggest a sensor for analysis of flavonoids in urine. It clearly follows from the results obtained that flavonoids can be analysed in the presence of animal urine, because urine did not influence much the signals of flavonoids (recoveries of the signals were about 90 %).
Shapes of Differential Pulse Voltammograms and Level of Metallothionein at Different Animal Species
Authors: Adam Vojtech , Beklova Miroslava , Pikula Jiri , Hubalek Jaromir , Trnkova Libuse , Kizek Rene
Published: October 2008

Metallothioneins play a key role in maintaining homeostasis of essential metalsand in protecting of cells against metal toxicity as well as oxidative damaging. Exceptinghumans, blood levels of metallothionein have not yet been reported from any animalspecies. Blood plasma samples of 9 animal species were analysed by the adsorptive transferstripping technique to obtain species specific voltammograms. Quite distinct records wereobtained from the Takin (Budorcas taxicolor), while other interesting records were observedin samples from the European Bison (Bison bonasus bonasus) and the Red-eared Slider(Trachemys scripta elegans). To quantify metallothionein the catalytic peak Cat2 was used,well developed in the Domestic Fowl (Gallus gallus f. domestica) and showing a very lowsignal in the Red Deer (Cervus elaphus). The highest levels of metallothionein reachingover 20 μM were found in the Domestic Fowl. High levels of MT were also found in theBearded Dragon (Pogona vitticeps) and the Grey Wolf (Canis lupus lupus). The lowestvalues of about 1-3 μM were determined in the Red-eared Slider, Takin and Red Deer. Employing a simple electrochemical detection it was possible to examine variation in blood metallothionein in different species of vertebrates.
Planar Array Sensor for High-speed Component Distribution Imaging in Fluid Flow Applications
Authors: Da Silva Marco Jose , Sühnel Tobias , Schleicher Eckhard , Vaibar Roman , Lucas Dirk , Hampel Uwe
Published: October 2008

A novel planar array sensor based on electrical conductivity measurements ispresented which may be applied to visualize surface fluid distributions. The sensor ismanufactured using printed-circuit board fabrication technology and comprises of 64 x 64interdigital sensing structures. An associated electronics measures the electricalconductivity of the fluid over each individual sensing structure in a multiplexed manner byapplying a bipolar excitation voltage and by measuring the electrical current flowing from adriver electrode to a sensing electrode. After interrogating all sensing structures, a two-dimensional image of the conductivity distribution over a surface is obtained which in turnrepresents fluid distributions over sensor’s surface. The employed electronics can acquire upto 2500 frames per second thus being able to monitor fast transient phenomena. The systemhas been evaluated regarding measurement accuracy and depth sensitivity. Furthermore, theapplication of the sensor in the investigation of two different flow applications is presented.
Electrochemical Sensor for Tryptophan Determination Based on Copper-cobalt Hexacyanoferrate Film Modified Graphite Electrode
Authors: Liu Yingju , Xu Li
Published: October 2008

In this work, the development of a tryptophan sensor and its application to milkare described. The mixed metal (copper and cobalt) hexacynoferrates are electrodepositedon the graphite electrode, and this film exhibits an electrocatalytic activity towards for theoxidation of tryptophan. The experimental conditions, including the scan cycles, the ratio ofcopper(II) and cobalt(II), pH value, applied potential, are investigated in detail. At theoptimal conditions, the eletctrocatalytic response is a linear relationship with theconcentration of tryptophan in the range of 10 μM and 900 μM, with a detection limit ofabout 6 μM. This modified electrode was also successfully used to detect the tryptophanconcentration in milk.
Operational Mapping of Soil Moisture Using Synthetic Aperture Radar Data: Application to the Touch Basin (France)
Authors: Baghdadi Nicolas , Aubert Maelle , Cerdan Olivier , Franchistéguy Laurent , Viel Christian , Eric Martin , Zribi Mehrez , Desprats Jean François
Published: October 2008

Soil moisture is a key parameter in different environmental applications, suchas hydrology and natural risk assessment. In this paper, surface soil moisture mappingwas carried out over a basin in France using satellite synthetic aperture radar (SAR)images acquired in 2006 and 2007 by C-band (5.3 GHz) sensors. The comparisonbetween soil moisture estimated from SAR data and in situ measurements shows goodagreement, with a mapping accuracy better than 3%. This result shows that themonitoring of soil moisture from SAR images is possible in operational phase. Moreover,moistures simulated by the operational Météo-France ISBA soil-vegetation-atmospheretransfer model in the SIM-Safran-ISBA-Modcou chain were compared to radar moistureestimates to validate its pertinence. The difference between ISBA simulations and radarestimates fluctuates between 0.4 and 10% (RMSE). The comparison between ISBA andgravimetric measurements of the 12 March 2007 shows a RMSE of about 6%. Generally,these results are very encouraging. Results show also that the soil moisture estimatedfrom SAR images is not correlated with the textural units defined in the European Soil Geographical Database (SGDBE) at 1:1000000 scale. However, dependence was observed between texture maps and ISBA moisture. This dependence is induced by the use of the texture map as an input parameter in the ISBA model. Even if this parameter is very important for soil moisture estimations, radar results shown that the textural map scale at 1:1000000 is not appropriate to differentiate moistures zones.
D-galactose/D-glucose-binding Protein from Escherichia coli as Probe for a Non-consuming Glucose Implantable Fluorescence Biosensor
Authors: Scognamiglio Viviana , Aurilia Vincenzo , Cennamo Nunzio , Ringhieri Paola , Iozzino Luisa , Tartaglia Micaela , Staiano Maria , Ruggiero Giuseppe , Orlando Pierangelo , Labella Tullio , Zeni Luigi , Vitale Annalisa , D’Auria Sabato
Published: October 2008

D-Galactose/D-glucose-binding protein from E. coli (GGBP) is a monomer thatbinds glucose with high affinity. The protein structure of GGBP is organized in twoprincipal domains linked by a hinge region that form the sugar-binding site. In this workwe show that the mutant form of GGBP at the amino acid position 182 can be utilized as aprobe for the development of a non-consuming analyte fluorescence biosensor to monitorthe glucose level in diabetes health care.
Refractive Index Measurement within a Photonic Crystal Fibre Based on Short Wavelength Diffraction
Authors: Martelli Cicero , Canning John , Kristensen Martin , Groothoff Nathaniel
Published: October 2008

A new class of refractive index sensors using solid core photonic crystal fibres isdemonstrated. Coherent scattering at the cladding lattice is used to optically characterizematerials inserted into the fibre holes. The liquid to solid phase transition of water uponfreezing to ice 1h is characterized by determining the refractive index.
Formation and Fluorimetric Characterization of Micelles in a Micro-flow Through System with Static Micro Mixer
Authors: Schuch Michael , Groß G. Alexander , Köhler J. Michael
Published: October 2008

The formation and behaviour of micelles of sodium dodecylsulfate in water byuse of a static micro mixer were studied. Trisbipyridylruthenium(II) was applied asindicator dye, 9-methylanthracene was used for fluorescence quenching. All experimentswere carried out by a micro fluid arrangement with three syringe pumps, a 2 1 two-stepstatic micro mixer (IPHT Jena) and a on-line micro fluorimetry including a luminescencediode for excitation, a blue glass filter (BG 7, Linos), two edge filters (RG 630, Linos) anda photo counting module (MP 900, Perkin Elmer). It was possible to measure thefluorescence inside the PTFE tube (inner diameter 0.5 mm) directly. A linear dependenceof fluorescence intensity from dye concentration was observed in absence of quencher andsurfactant as expected. An aggregation number of about 62 was found in the flow raterange between 300 and 800 μL/min. The fluorescence intensity increases slightly, butsignificant with increasing flow rate, if no quencher is present. In the presence of quencher,the fluorescence intensity decreases with decreasing surfactant concentration and withenhanced flow rate. The strength of the flow rate effect on the fluorescence increases withdecreasing surfactant concentration. The size of micelles was determined in micro channelsby the micro fluorimetric method in analogy to the conventional system. The micellesextract the quencher from the solution and lower, this way, the quenching effect. The sizeof micelles was estimated and it could be shown, that the flow rate has only low effect onthe aggregation number at the investigated flow rates. The effect of flow rate andsurfactant concentration on the fluorescence in the presence of quencher was interpreted asa shift in the micelle concentration due to the shear forces. It is expected, that thefluorescence intensity is lowered, if more quencher molecules are molecular disperse distributed inside the solution. Obviously, the lowered fluorescence intensity at higher flow rates suggests a reduction of the micelle density causing an increase of quencher concentration outside the micelles.
Electrochemical Detection of a Dengue-related Oligonucleotide Sequence Using Ferrocenium as a Hybridization Indicator
Authors: Ribeiro Teles Fernando Rodrigues , França dos Prazeres Duarte Miguel , De Lima-Filho José Luiz
Published: October 2008

A simple method for electrochemical detection of a synthetic 20-bpoligonucleotide sequence related with dengue virus genome was developed. Acomplimentary DNA probe sequence was electrostatically immobilized onto a glassycarbon electrode modified with chitosan. Electrochemical detection of hybridizationbetween probe and target was performed by cyclic voltammetry, using ferrocene (Fc ) as ahybridization label. After hybridization, the peak current response of Fc oxidationincreased around 26%. A higher voltammetric decay rate constant (kd) and a lower half-lifeperiod (t1/2) for the interaction of Fc with dsDNA compared to those with ssDNAquantitatively characterize the different strengths of interaction with both types of DNA.By combining the simplicity of DNA immobilization onto a chitosan film and suitablevoltammetric detection of hybridization concomitant with ferrocene attachment, a gooddiscrimination between ssDNA and dsDNA was obtained.
Sub-pixel Area Calculation Methods for Estimating Irrigated Areas
Authors: Thenkabailc Prasad S. , Biradar Chandrashekar M. , Noojipady Praveen , Cai Xueliang , Dheeravath Venkateswarlu , Li Yuanjie , Velpuri Manohar , Gumma Muralikrishna , Pandey Suraj
Published: October 2008

The goal of this paper was to develop and demonstrate practical methods forcomputing sub-pixel areas (SPAs) from coarse-resolution satellite sensor data. Themethods were tested and verified using: (a) global irrigated area map (GIAM) at 10-kmresolution based, primarily, on AVHRR data, and (b) irrigated area map for India at 500-mbased, primarily, on MODIS data. The sub-pixel irrigated areas (SPIAs) from coarse-resolution satellite sensor data were estimated by multiplying the full pixel irrigated areas(FPIAs) with irrigated area fractions (IAFs). Three methods were presented for IAFcomputation: (a) Google Earth Estimate (IAF-GEE); (b) High resolution imagery (IAF-HRI); and (c) Sub-pixel de-composition technique (IAF-SPDT). The IAF-GEE involvedthe use of “zoom-in-views” of sub-meter to 4-meter very high resolution imagery (VHRI)from Google Earth and helped determine total area available for irrigation (TAAI) or netirrigated areas that does not consider intensity or seasonality of irrigation. The IAF-HRI isa well known method that uses finer-resolution data to determine SPAs of the coarser-resolution imagery. The IAF-SPDT is a unique and innovative method wherein SPAs aredetermined based on the precise location of every pixel of a class in 2-dimensionalbrightness-greenness-wetness (BGW) feature-space plot of red band versus near-infraredband spectral reflectivity. The SPIAs computed using IAF-SPDT for the GIAM was within2 % of the SPIA computed using well known IAF-HRI. Further the fractions from the 2 methods were significantly correlated. The IAF-HRI and IAF-SPDT help to determine annualized or gross irrigated areas (AIA) that does consider intensity or seasonality (e.g., sum of areas from season 1, season 2, and continuous year-round crops). The national census based irrigated areas for the top 40 irrigated nations (which covers about 90% of global irrigation) was significantly better related (and had lesser uncertainties and errors) when compared to SPIAs than FPIAs derived using 10-km and 500-m data. The SPIAs were closer to actual areas whereas FPIAs grossly over-estimate areas. The research clearly demonstrated the value and the importance of sub-pixel areas as opposed to full pixel areas and presented 3 innovative methods for computing the same.
Flexible Time-Triggered Sampling in Smart Sensor-Based Wireless Control Systems
Authors: Xia Feng , Zhao Wenhong
Published: October 2008

Wireless control systems (WCSs) often have to operate in dynamic environmentswhere the network traffic load may vary unpredictably over time. The sampling in sensors isconventionally time triggered with fixed periods. In this context, only worse-than-possiblequality of control (QoC) can be achieved when the network is underloaded, whileoverloaded conditions may significantly degrade the QoC, even causing system instability.This is particularly true when the bandwidth of the wireless network is limited and sharedby multiple control loops. To address these problems, a flexible time-triggered samplingscheme is presented in this work. Smart sensors are used to facilitate dynamic adjustment ofsampling periods, which enhances the flexibility and resource efficiency of the system basedon time-triggered sampling. Feedback control technology is exploited for adapting samplingperiods in a periodic manner. The deadline miss ratio in each control loop is maintainedat/around a desired level, regardless of workload variations. Simulation results show that theproposed sampling scheme is able to deal with dynamic and unpredictable variations innetwork traffic load. Compared to conventional time-triggered sampling, it leads to muchbetter QoC in WCSs operating in dynamic environments.
Mapping and Assessment of Degraded Land in the Heihe River Basin, Arid Northwestern China
Authors: Qi Shanzhong , Cai Yumin
Published: October 2008

Land degradation is a great threat in the Heihe River Basin, located in the aridinland of northwestern China and land desertification is one of the main aspects ofenvironmental changes in this basin. Previous studies have focused on water resourceutilization and soil erosion, but the status of degraded land in the Heihe River Basin, suchas its distribution, extent and precise characteristics is often inadequately known. Based onfield observations and TM images from the year 2003, this study provides classificationand evaluation information concerning the degraded land in the basin of the Heihe River.There are five types of degraded land types in the Heihe River Basin: water eroded in thesouthern mountains, sandified and vegetation degraded near the oases, aridized in the lowreaches, and salinized in the lowlands. The total degraded area covers 29,355.5 km2,22.58% of the land in the study area. Finally, degraded land in the Heihe River Basin wasevaluated according to changes in the physical structure and chemical components of soils,land productivity, secondary soil salt, and water conditions.
Determining Position Inside Non-industrial Buildings Using Ultrasound Transducers
Authors: Escudero Francesc , Margalef Jordi , Luengo Sonia , Alsina Maria , Ribes Josep M. , Pérez Juan
Published: October 2008

The position determination inside a building where no GPS signal is beingreceived can be ascertained using laser transmitters in industrial situations where there areno people or using triangulation of the signal strength, normally electro-magnetic signals,if the required accuracy is more than a metre. Our solution is aimed at situations wherepeople are present and where the required accuracy is less than 30 cm, such as in shoppingprecincts or supermarkets. To achieve this, a network of ultrasonic transmitters is fittedinto the ceiling which receives a synchronised time signal. Each transmitter has a uniqueidentifier code and emits its code with a delay with respect to the common time signalwhich is proportional to its code number with an ASK modulation over the ultrasonic bandcentred on 40 KHz. The receivers circulating beneath the transmitters receive the codes ofthose within their detection range, translate the time delays into distances and then obtaintheir position by triangulation since the receivers know the position of every transmitter.Since the receivers are not synchronised with the common time signal or the actual speedof the sound, whose value varies appreciably with temperature, relative humidity andatmospheric pressure, a consecutive approximation algorithm has been introduced. This isbased on the fact that the Z coordinator of the receiver is known and constant and thus it is possible, with only three different identifiers received, to deduce the phase of the common time signal and estimate the speed of the sound with a fourth identifier.
Biochemical Markers for Assessing Aquatic Contamination
Authors: Havelková Marcela , Randák Tomáš , Žlábek Vladimír , Krijt Jan , Kroupová Hana , Pulkrabová Jana , Svobodová Zdeňka
Published: October 2008

Biochemical markers, specifically enzymes of the first phase of xenobiotic transformation - cytochrome P450 and ethoxyresorufin-O-deethylase (EROD) - were used to determine the quantities of persistent organic pollutants (POPs) in fish muscle (PCB, HCB, HCH, OCS, DDT). Eight rivers were monitored (Orlice, Chrudimka, Cidlina, Jizera, Vltava, Ohře and Bílina; and the River Blanice was used as a control). The indicator species selected was the chub (Leuciscus cephalus L.). There were no significant differences in cytochrome P450 content between the locations monitored. The highest concentration of cytochrome P450 in fish liver was in the Vltava (0.241 nmol mg-1 protein), and the lowest was in the Orlice (0.120 nmol mg-1 protein). Analysis of EROD activity showed a significant difference between the Blanice and the Vltava (P< 0.05), and also between the Orlice and the Vltava (P< 0.01), the Orlice and the Bílina (P< 0.01), and the Orlice and the Ohře (P< 0.05). The highest EROD activity in fish liver was in the Vltava (576.4 pmol min-1 mg-1 protein), and the lowest was in the Orlice (63.05 pmol min-1 mg-1 protein). In individual locations, results of chemical monitoring and values of biochemical markers were compared. A significant correlation (P< 0.05) was found between biochemical markers and OCS, and PCB. Among the tributaries studied those that contaminated the Elbe most were the Vltava and the Bílina. These tributaries should not be considered the main sources of industrial contamination of the River Elbe, because the most important contamination sources were along the river Elbe itself.
Glucose Determination by Means of Steady-state and Time-course UV Fluorescence in Free or Immobilized Glucose Oxidase
Authors: De Luca Paola , Lepore Maria , Portaccio Marianna , Esposito Rosario , Rossi Sergio , Bencivenga Umberto , Mita Damiano Gustavo
Published: October 2008

Changes in steady-state UV fluorescence emission from free or immobilizedglucose oxidase have been investigated as a function of glucose concentration.Immobilized GOD has been obtained by entrapment into a gelatine membrane. Changes insteady-state UV fluorescence have been quantitatively characterized by means ofoptokinetic parameters and their values have been compared with those previouslyobtained for FAD fluorescence in the visible range. The results confirmed that greatercalibration ranges are obtained from UV signals both for free and immobilized GOD inrespect to those obtained under visible fluorescence excitation. An alternative method tothe use UV fluorescence for glucose determination has been investigated by using timecourse measurements for monitoring the differential fluorescence of the redox forms of theFAD in GOD. Also in this case quantitative analysis have been carried out and acomparison with different experimental configurations has been performed. Time coarsemeasurements could be particularly useful for glucose monitoring in complex biologicalfluids in which the intrinsic UV fluorescence of GOD could be not specific by consideringthe presence of numerous proteins.
Carbon-based Composite Electrodes: Preparation, Characterization and Application in Electroanalysis
Authors: Corb Ioana , Manea Florica , Radovan Ciprian , Pop Aniela , Burtica Georgeta , Malchev Plamen , Picken Stephen , Schoonman Joop
Published: October 2008

Electrodes based on carbon, i.e., expanded graphite (20%, wt.)-epoxy composite(20EG-Epoxy) and expanded graphite (20%, wt.)-polystyrene composite (20EG-PS) havebeen prepared, characterized using scanning electron microscopy (SEM) and cyclicvoltammetry (CV), and tested as anodic sensors. The electrodes exhibited good mechanicalresistance and low electrical resistances. Scan rate dependent cyclic voltammetry responsesat 20EG-Epoxy and 20EG-PS composite electrodes, which were exemplified for thiourea(TU), a toxic sulphur organic compound selected as testing target analyte in 0.1 M Na2SO4 supporting electrolyte, were investigated. The obtained voltammetric data were inaccordance with those for a random array of microelectrodes. The voltammetric andchronoamperometric detection results of TU in tap water samples, without a supplementaryaddition of supporting electrolyte, at 20EG-Epoxy electrode proved its use for directanalysis of environmental samples.
Sensitivity of the Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) to Topographic Effects: A Case Study in High-density Cypress Forest
Authors: Matsushita Bunkei , Yang Wei , Chen Jin , Onda Yuyichi , Qiu Guoyu
Published: October 2008

Vegetation indices play an important role in monitoring variations in vegetation.The Enhanced Vegetation Index (EVI) proposed by the MODIS Land Discipline Groupand the Normalized Difference Vegetation Index (NDVI) are both global-based vegetationindices aimed at providing consistent spatial and temporal information regarding globalvegetation. However, many environmental factors such as atmospheric conditions and soilbackground may produce errors in these indices. The topographic effect is another veryimportant factor, especially when the indices are used in areas of rough terrain. In thispaper, we theoretically analyzed differences in the topographic effect on the EVI and theNDVI based on a non-Lambertian model and two airborne-based images acquired from amountainous area covered by high-density Japanese cypress plantation were used as a casestudy. The results indicate that the soil adjustment factor “L” in the EVI makes it moresensitive to topographic conditions than is the NDVI. Based on these results, we stronglyrecommend that the topographic effect should be removed in the reflectance data beforethe EVI was calculated—as well as from other vegetation indices that similarly include a term without a band ratio format (e.g., the PVI and SAVI)—when these indices are used in the area of rough terrain, where the topographic effect on the vegetation indices having only a band ratio format (e.g., the NDVI) can usually be ignored.
Application to Temperature Sensor Based on Green Up-conversion of Er3+ Doped Silicate Glass
Authors: Li Chengren , Dong Bin , Ming Chengguo , Lei Mingkai
Published: October 2008

The green up-conversion emissions centered at the wavelengths of about 534nmand 549nm of the Er3+ doped silicate glass were recorded, using a 978 nm semiconductorlaser diode (LD) as an excitation source. The fluorescence intensity ratio (FIR) of the greenup-conversion emissions at about 534nm and 549nm in the Er3+ doped silicate glass wasstudied as a function of temperature over the temperature range of 296K-673K. Themaximum sensitivity and the temperature resolution derived from the FIR of the green up-conversion emissions are approximately 0.0023K-1 and 0.8K, respectively. It isdemonstrated that the prototype optical temperature sensor based on the FIR technique fromthe green up-conversion emissions in the Er3+ doped silicate glass could play a major role intemperature measurement.
Modeling and Manufacturing of Micromechanical RF Switch with Inductors
Authors: Dai Ching-Liang , Chen Ying-Liang
Published: October 2008

This study presents the simulation, fabrication and characterization ofmicromechanical radio frequency (RF) switch with micro inductors. The inductors areemployed to enhance the characteristic of the RF switch. An equivalent circuit model isdeveloped to simulate the performance of the RF switch. The behaviors of themicromechanical RF switch are simulated by the finite element method software,CoventorWare. The micromechanical RF switch is fabricated using the complementarymetal oxide semiconductor (CMOS) and a post-process. The post-process employs a wetetching to etch the sacrificial layer, and to release the suspended structures of the RF switch.The structure of the RF switch contains a coplanar waveguide (CPW), a suspendedmembrane, eight springs and two inductors in series. Experimental results reveal that theinsertion loss and isolation of the switch are 1.7 dB at 21 GHz and 19 dB at 21 GHz,respectively. The driving voltage of the switch is about 13 V.
Electrochemical Interrogation of Interactions between Surface-Confined DNA and Methylene Blue
Authors: Pan Dun , Zuo Xiaolei , Wan Ying , Wang Lihua , Zhang Jiong , Song Shiping , Fan Chunhai
Published: October 2008

In this work, we reported a systematic investigation on the interactions betweenmethylene blue (MB) and surface-confined DNA by using electrochemical methods. Wedemonstrated that the redox potential of MB and binding and dissociation kinetics of MB toDNA differed significantly for single-stranded DNA (ss-DNA) and double-stranded DNA(ds-DNA) immobilized on gold electrodes. This was possibly due to the different bindingmechanism between MB and ss- or ds-DNA. This work might provide useful informationfor developing MB-based sequence-specific electrochemical DNA sensors.
Four-Wire Impedance Spectroscopy on Planar Zeolite/Chromium Oxide Based Hydrocarbon Gas Sensors
Authors: Hagen Gunter , Schulz Anne , Knörr Matthias , Moos Ralf
Published: October 2008

Impedometric zeolite hydrocarbon sensors with a chromium oxide intermediatelayer show a very promising behavior with respect to sensitivity and selectivity. Theunderlying physico-chemical mechanism is under investigation at the moment. In order toverify that the effect occurs at the electrode and that zeolite bulk properties remain almostunaffected by hydrocarbons, a special planar setup was designed, which is very close to realsensor devices. It allows for conducting four-wire impedance spectroscopy as well as two-wire impedance spectroscopy. Using this setup, it could be clearly demonstrated that thesensing effect can be ascribed to an electrode impedance. Furthermore, by combining two-and four-wire impedance measurements at only one single frequency, the interference of thevolume impedance can be suppressed and an easy signal evaluation is possible, withouttaking impedance data at different frequencies.
Hierarchical Wireless Multimedia Sensor Networks for Collaborative Hybrid Semi-Supervised Classifier Learning
Authors: Wang Xue , Wang Sheng , Bi Daowei , Ding Liang
Published: October 2008

Wireless multimedia sensor networks (WMSN) have recently emerged as one ofthe most important technologies, driven by the powerful multimedia signal acquisition andprocessing abilities. Target classification is an important research issue addressed in WMSN,which has strict requirement in robustness, quickness and accuracy. This paper proposes acollaborative semi-supervised classifier learning algorithm to achieve durative onlinelearning for support vector machine (SVM) based robust target classification. The proposedalgorithm incrementally carries out the semi-supervised classifier learning process inhierarchical WMSN, with the collaboration of multiple sensor nodes in a hybrid computingparadigm. For decreasing the energy consumption and improving the performance, somemetrics are introduced to evaluate the effectiveness of the samples in specific sensor nodes,and a sensor node selection strategy is also proposed to reduce the impact of inevitablemissing detection and false detection. With the ant optimization routing, the learningprocess is implemented with the selected sensor nodes, which can decrease the energyconsumption. Experimental results demonstrate that the collaborative hybrid semi-supervised classifier learning algorithm can effectively implement target classification inhierarchical WMSN. It has outstanding performance in terms of energy efficiency and timecost, which verifies the effectiveness of the sensor nodes selection and ant optimizationrouting.
Modelling a Peroxidase-based Optical Biosensor
Authors: Baronas Romas , Gaidamauskait˙e Evelina , Kulys Juozas
Published: October 2008

The response of a peroxidase-based optical biosensor was modelled digitally.A mathematical model of the optical biosensor is based on a system of non-linear reaction-diffusion equations. The modelling biosensor comprises two compartments, an enzyme layerand an outer diffusion layer. The digital simulation was carried out using finite differencetechnique. The influence of the substrate concentration as well as of the thickness of both theenzyme and diffusion layers on the biosensor response was investigated. Calculations showedcomplex kinetics of the biosensor response, especially at low concentrations of the peroxidaseand of the hydrogen peroxide.
Ammonia Optical Sensing by Microring Resonators
Authors: Passaro Vittorio M. N. , Dell’Olio Francesco , De Leonardis Francesco
Published: October 2008

A very compact (device area around 40 μm2) optical ammonia sensor based on amicroring resonator is presented in this work. Silicon-on-insulator technology is used insensor design and a dye doped polymer is adopted as sensing material. The sensor exhibitsa very good linearity and a minimum detectable refractive index shift of sensing materialas low as 8x10-5, with a detection limit around 4 ‰.
Metalloporphyrin - based Electronic Tongue: an Application for the Analysis of Italian White wines
Authors: Verrelli Giorgio , Lvova Larisa , Paolesse Roberto , Di Natale Corrado , D'Amico Arnaldo
Published: October 2008

An Electronic Tongue system (ET) composed of “all-solid-state” potentiometricsensors was developed and applied for the identification of white wines. The sensingproperties were due to the PVC based membranes doped with several metallo-porphyrinsdeposited on the surface of glassy carbon working electrodes; potentiometric responsetowards several ions in a concentration range from 10-5 M to 10-1 M were studied and cross-sensitivity of sensors was estimated. The sensor array was applied both for the classificationand quantitative analysis of “Verdicchio D.O.C.” Italian dry white wines produced by ninecantinas. Peculiar parameters of white wines (namely alcoholic degree, volatile acidity, SO2,L-Malic Acid, L-Lactic Acid and Total Polyphenols) individuated by standard analyticalmethods were compared with the values evaluated by metalloporphyrin-based ET. Thesystem satisfactory discriminates between an artificial wine control and analyzed winescoming from different cantinas and produced in different years. A satisfactory correlationbetween results of wine analysis performed by certified methods and ET response has beenobtained for SO2, L-Malic Acid, and Total Phenols content. The developed procedureallows the monitoring of the acetic acid amount in wines and hence to control wine volatileacidity, so indicating the initial steps of wine spoilage process.