bluuebunny/crossref_metadata_2025 huggingface dataset:
A Combined Model for the Stress State Evaluation in Single Overlap Joints Using Piezo-Ceramic Actuators
Authors: Paltanea Gheorghe , Manescu Paltanea Veronica , Popovici Dorina , Papanicolaou George , Sultan Mihael
Published: August 2014

In this paper is presented a 2D approach to finite element modeling of a single lap bonded joint. As adherent material a sheet wood was selected and as adhesive, Bison Super Wood D3. In the article a combined method is described, consisting in the placement of piezoelectric actuators on the surface of bonded joint, in order to determine the tensile stress in the overlap joint. A comparison between the experimental, analytical and numerical results has been achieved through a multiphysics modeling - electrical and mechanical coupled problem, in order to evaluate the experimental outcomes. The experimental technique used to measure the mechanical parameters (displacements) was the three-point bending test, where different forces were applied in the mid-span of the structure, in order to maintain a constant displacement rate. The length of the overlap joint was modified from 20 to 50 mm.
Design and Test Procedures for EMI Filters Used for Nonlinear Loads
Authors: Buzdugan Mircea , Balan Horia
Published: August 2014

This paper analyzes an EMI filter solution to diminish the effect of harmonics generated by PWM converters in active filters. Throughout this paper, we have presented specific problems regarding the design, simulation and the validation of the model by testing EMI filters. It can be mentioned that the tests of the experimental model were performed in a laboratory, using existing conditions for the non linear consumer, by generating distorted waveforms.
Maximum Hoop Stress Evaluation of a Hollow Cylindrical Bulk Superconductor in Field-Cooled Magnetization
Authors: Tsuchimoto Masanori
Published: August 2014

Stresses are induced in a bulk high-Tc superconductor (HTS) by field-cooled magnetization. The stress distributions of a hollow cylindrical bulk HTS are numerically studied in the axisymmetric three-dimensional analysis. Shielding current distributions are obtained through a macroscopic numerical simulation with the Maxwell equations and the critical state model. Stress distributions are obtained by using the finite-difference method and iterative calculations. Maximum hoop stress during the field-cooled magnetization is discussed for open and fixed boundary conditions.
Development of Magnetic Coupling Utilizing Magnetic Material Attached Magnetic-Flux Concentrated Surface Permanent Magnet Arrangement
Authors: Hirakawa Takuya , Todaka Takashi , Enokizono Masato
Published: August 2014

This paper presents a magnetic coupling for a large-sized mixer, which is separated by a vessel wall. In order to improve the transmission-torque, the magnetic material attached magnetic-flux concentrated surface permanent magnet (MCSPM) arrangement is applied to the magnetic coupling and the construction is optimized. The results show that the MCSPM arrangement is very effective to improve the air-gap magnetic flux density and the transmission torque even quantity of very few permanent magnets.
Dynamic Magnetic Field and Oscillating Simulations of a Hybrid Magnetic Suspension System Utilizing Permanent Magnets
Authors: Utsunomiya Kenshiro , Todaka Takashi , Enokizono Masato
Published: August 2014

This paper presents vibration characteristics of a hybrid magnetic suspension model combining functions of a magnetic spring and a magnetic damper. Dynamic simulations considering the moving equation are performed with the step-by-step method based on the time-domain three-dimensional axisymmetric finite element method. The results demonstrate that the proposed hybrid model is effective to improve the performance to attenuate vibrations.
"In Situ" Evaluation of Ferromagnetic Bodies Magnetic Characteristics
Authors: Gavrila Horia , Stanculescu Marilena , Maricaru Mihai , Vasilescu Marian , Andrei Paul , Hantila Ioan Florea
Published: August 2014

The B-H characteristic of an iron body material influences the magnetic field measured in the air. On principle, one can pose the problem of B-H relation determination, by making measurements of the magnetic induction in the neighbourhood of the body. Unfortunately, we have an ill-posed inverse magnetic field problem, for which there is possible that, big variations of the BH characteristic to produce only very small modifications of the magnetic field in the air. It is essential to use a sufficiently sensitive computation procedure in order to produce credible results. This paper proposes a device for the B-H characteristic evaluation, admitting that inside the ferromagnetic bodies the magnetic field distribution is not uniform.
Magnetic Testing of Power Plant Steel Deterioration
Authors: Mészáros István , Ginsztler János
Published: August 2014

Nowadays, there is increasing importance of the remaining life time estimation of engineering structures. In this work the thermal shock fatigue process induced deterioration of the three different power plant steels was investigated. The tested steels are widely used as steam pipeline base material of power plants. The applied thermal shock fatigue test can model the material degradation due to long term service in high temperature environment. A special AC magnetometer was designed and used for the magnetic measurements at the Department of Materials Science and Engineering of BUTE. In this paper a new high sensitivity magnetic measurement is presented for controlling the thermal shock fatigue deterioration. This measurement technique was developed for non-destructive testing of pipelines and pressure vessels of steam power plants.
Structure and Functional Properties of Bulk MgB2 Superconductors Synthesized and Sintered under Pressure
Authors: Prikhna Tatiana , Eisterer Michael , Gawalek Wolfgang , Mamalis Athanasios G. , Kozyrev Artem , Kovylaev Valeriy , Hristoforou Evangelos , Weber Harald W. , Noudem Jacques G. , Goldacker Wilfried , Moshchil Viktor , Chaud Xavier , Sokolovsky Vladimir , Shaternik Anton , Dellith Jan , Schmidt Christa , Habisreuther Tobias , Litzkendorf Doris , Dub Sergey , Borimskiy Alexander , Sergienko Nina , Sverdun Vladimir , Prisyazhnaya Elena
Published: August 2014

The high pressure (50 MPa - 2 GPa) – high temperature synthesized MgB2 bulk materials are characterized by nearly theoretical density (1-2% porosity), 80-98% connectivity, extremely high critical current densities (e.g. at 20 K, in 0–1 T jc=1.3–1.0 MA·cm-2 (with 10% SiC) and jc= 0.92 – 0.73 MA·cm-2 (without doping)), large irreversibility fields (Birr(18.4 K) =15 T and Birr (0 K) = 32.5 T) and high upper critical fields (Bc2 (22 K) =15 T and Bc2(0 K) ~ 42.1 T). The transformation of grain boundary pinning to point pinning in MgB2-based materials with increasing manufacturing temperature (from 800 to 1050 oC) under pressures from 0.1 to 2 GPa correlates well with an increase in critical current density in low external magnetic fields caused by the redistribution of boron and the oxygen impurities in the material structure. As the manufacturing temperature increases, the discontinuous oxygen enriched layers transform into distinct Mg-B-O inclusions and the size and amount of inclusions of higher magnesium borides MgBX (X>4) are reduced. The effect of oxygen and boron redistribution can be enhanced by Ti or SiC additions.
Study on Force-Transmissibility of a Magnetic Gear by Using 3-D Boundary Element Analysis
Authors: Oka Masaru , Todaka Takashi , Enokizono Masato
Published: August 2014

This paper presents three-dimensional boundary element analysis for coupled magnetic field and moving problem. The method is applied to improve transmission characteristics of a magnetic gear and the usefulness is demonstrated. The gear has two movers consisting of permanent magnets and they rotate with different velocity. The double gap moving problem is very time consuming, because the mesh has to be regenerated at each time step or prepared many patterns previously. The use of the boundary element method is suitable for this problem, because meshes are required around only surfaces of considering objects and the objects can be rotated any angle according to the moving simulation. In this paper, the technique to reduce unknown variables in the boundary element equations utilizing symmetrical construction is proposed.
Precise Crosstalk Assessment in Complex Nanointerconnects via a Family of Unconditionally-Stable Nonstandard Time-Domain Algorithms
Authors: Kantartzis Nikolaos , Ohtani Tadao , Kanai Yasushi , Tsiboukis Theodoros
Published: August 2014

A class of nonstandard locally one-dimensional finite-difference time-domain schemes is developed in this paper for the accurate characterization of crosstalk and intermodulation distortions in complicated nanostructured interconnects. The novel 3-D methodology introduces a general curvilinear discretization to consistently treat the rapidly varying frequency-dependent behavior of these lossy materials. In this way, the resulting high-order forms minimize the artificial dispersion and dissipation errors of usual approaches and guarantee the unconditional stability of far shorter simulations. Numerical results, compared with measurement data, verify the assets of the proposed technique via the study of various fabric/epoxy devices with nanocomposite media.
Geometry Optimization of Synchronous Machines Used on Ship Shaft Generator Systems
Authors: Sarigiannidis Athanasios G. , Patsios C. , Pittaras A. , Kladas A.
Published: August 2014

In this paper, the geometry optimization and analysis of two synchronous machines for ship shaft generator applications was carried out. The use of shaft generators in marine applications is a convenient and effective way to supply electric energy to the ship, operating in conjunction with conventional diesel generators. On a first step, state of the art topologies of shaft generator systems are identified and evaluated. In addition, potential improvements in shaft generator systems are proposed. On a second step, a low-speed, direct-driven Permanent Magnet Synchronous Generator (PMSG) for shaft generator applications is designed and optimized in terms of torque production as well as efficiency. The PMSG is compared with an equal power Salient-Pole generator driven by a step-up gear, which is a set-up commonly used in shaft generator systems. The machines are evaluated and optimized in terms of torque production, efficiency and electromotive forces (EMF) harmonic content in nominal operating conditions.
Modelling and Optimization of Induction Cooking by the Use of Magneto-Thermal Finite Element Analysis and Neural Network
Authors: Allaoui F. , Kanssab A. , Matallah M. , Zoui A. , Feliachi M.
Published: August 2014

The main advantage of induction cooking is the pan heating without thermal inertia.However to obtain best efficiency, it is essential to have an inductor geometry that gives ahomogeneous temperature on the pan bottom. In this paper, we will first model the magnetothermal phenomena of the system by a finite element method (FEM) in order to determine thedistribution of temperature on the pan bottom taking into consideration the nonlinearity of thesystem. This study shows that the temperature is not homogeneously distributed. Then, in the aim tohave homogeneous temperature distribution in the pan bottom, we propose an inductor structurewith four throats containing the coils and we will use Neural Networks to determine the optimalthroats distribution and their dimensions. The optimized structure permits us to achieve our goal.
Behavior of Particles in the Process of Magnetic Compound Fluid Polishing of Inner Surface of Micro-Tube with Axial Flow
Authors: Ido Yasushi , Asakura Keisuke , Nishida Hitoshi
Published: August 2014

Behavior of both suspended micrometer-size magnetic particles and micrometer-size nonmagnetic abrasive particles in a micro-tube filled with a magnetic compound fluid is investigated by using discrete particles method based on the simplified Stokesian dynamics in order to reveal the polishing process of inner surface of the tube with an axial flow. Giving the axial flow of the appropriate velocity is effective on performing uniform polishing of the surface in the magnetic compound fluid polishing.
Series Resonance Technique for Short-Circuit Current Limiting Devices in DC Grids
Authors: Balan Horia , Buzdugan Mircea , Pop Adrian Augustin
Published: August 2014

The paper presents a by-pass solution used to limit the short-circuit current in the DC networks. The aim of the by-pass circuit consists in injecting a reverse current throughout the power switch, in order that switching achieves at low current value. The reverse current generation is obtained using a series resonant circuit, simulated in the paper in the Matlab-Simulink medium, the results of the simulation being compared to the experimental ones.
Shock Loading of Advanced Materials from Macro-, Micro- to Nanoscale
Authors: Mamalis Athanasios G.
Published: August 2014

Some of the activities of the Project Center for Nanotechnology and Advanced Engineering (PC-NAE), a joint initiative of the Greek National Center for Scientific Research Demokritos and the Russian Research Center Kurchatov Institute, in advanced manufacturing engineering are briefly outlined, focusing onto some recent trends and developments in manufacturing from macro-, micro-, to nanoscale of advanced materials in the important engineering topics nowadays from industrial, research and academic point of view: nanotechnology/ultraprecision engineering and advanced materials under shock loading, with industrial applications to net-shape manufacturing, bioengineering, energy and transport.
Investigation of Shielding Materials Impact on the Effectiveness of UAV FSO Communication Systems
Authors: Hatziefremidis Antonios , Spathopoulos Vassilios , Amoiralis Eleftherios I. , Tsili Marina A.
Published: August 2014

The use of Free Space Optics (FSO) for Unmanned Aerial Vehicle (UAV) communication is a relatively new innovation that could become a necessity for all scenarios where real-time delivery of high daterates is essential. The present paper investigates one of the challenges being faced by this type of system, in particular the relationship between shielding materials of the protective dome and the wavelength of the emitted photons.
Advanced Methodology for Proton Exchange Membrane Fuel Cell Representation Validated by Measurements
Authors: Avramiotis-Falireas Iason , Kladas Antonios
Published: August 2014

This study aims to the development of a simple dynamic model for Proton Exchange Membrane Fuel Cell (PEMFC). The equations representing the thermodynamic laws and describing the respective voltage drop are formulated and are integrated into a LarminieDicks topology lumped parameter equivalent circuit, in order to develop the proposed dynamic model. The model has been validated by experimental results on a fuel cell stack of 500W under both steady-state operation and transient behavior.
Adapting Smart Grid, RES Penetration, Electromagnetic Compatibility and Energy Efficiency Concepts to Electric Ship Power Systems
Authors: Moschakis Marios , Kanellos Fotis , Prousalidis John
Published: August 2014

This paper deals with the adaption of Smart Grid, RES penetration, Electromagnetic Compatibility and Energy Efficiency concepts from land to ship power systems. It presents a review on the state-of-art on those areas as regards the land power systems and attempts to propose some of those advances and how they can be adapted to ship power systems. Ship power systems have many resemblances mainly with autonomous land power systems. Thus, autonomous power systems will be used as a model for an accurate and successive adaption of those concepts.
Torque Characteristic Analysis of an IM/PM Hybrid Motor by Using Finite Element Method
Authors: Iwao Shingo , Todaka Takashi , Enokizono Masato
Published: August 2014

This paper presents torque characteristic analysis of synchronous induction motors called “IM/PM hybrid motors” by using the two-dimensional finite element method taking terminal voltage into account. The slip characteristics are analyzed by using multi-meshes corresponding to each rotor position, because the transient numerical analysis is quite difficult due to slip even two-dimensional analysis. There are many researches on IM/PM hybrid motors, however the torque characteristics when they are operating as an induction motor have not yet examined sufficiently. In this paper, we tried to explore how to improve the torque characteristics even operating as an induction motor by incorporating the embedded permanent magnets. The results show that the arrangement of the permanent magnets is very important to improve whole torque characteristics.
Relationship between Number of Teeth and Transmission Torque on Cylindrical Magnetic Gear
Authors: Ando Yoshinori , Onuma Takuya , Baba Akira , Murakami Iwanori , Yamada Kou
Published: August 2014

A magnetic gear transmits torque without contact. The torque just before the gear idling defines the maximum transmission torque of the magnetic gear. Today, many methods are studied well to increase the maximum transmission torque. But no attention is paid to the number of magnetic gear teeth. In this paper, we focus on the relationship between the number of teeth and the maximum transmission torque. In experiments, three types of the developed gears, which have the different number of teeth, are checked for the maximum transmission torque. As experimental results, we reveal influence of the teeth number to the transmission torque.
Parameter Extraction of a PM Machine Employing 3D Finite Element Analysis Tools for Model Predictive Control Schemes
Authors: Kakosimos Panagiotis E. , Beniakar Minos E. , Kimoulakis Nikolaos M. , Kladas Antonios
Published: August 2014

This paper introduces a permanent magnet (PM) machine model accounting for saturation effects and non-sinusoidal electromotive force (EMF) employed in model predictive control schemes. The procedure of the model parameters determination is based on the three dimensional finite element analysis (FEA) considering saturation and cross-coupling effects. The conventional equivalent circuit model is subject to modifications so as to incorporate data derived from FEA enabling the model predictive control strategies to obtain proper actions for the converter operation based on the accurate prediction of the machine performance. The regeneration of the n-order harmonic components of the non-sinusoidal EMF is attained by combining methods of superposition and approximation estimating the output voltage at the machine terminals for different loading and speed. Developed model simulation results have been validated by experiments performed on an inset PM machine prototype.
A Simple and Efficient Parametric Design Approach for Marine Electrical Machines
Authors: Patsios Charalampos , Beniakar Minos E. , Kladas Antonios , Prousalidis John
Published: August 2014

In this paper a parametric design procedure of electrical machines used in naval propulsion systems is developed. The algorithm uses a series of design characteristics i.e. the type of the machine, the winding configuration and key geometrical properties, as parameters and is implemented on MATLAB® script allowing for a straightforward incorporation with other development tools. Using the proposed algorithm, two of the most common machine configurations involved in marine electrical propulsion systems i.e. the Induction Motor and the Synchronous Permanent Magnet Motor, are designed and 2D finite element modeling and analysis is performed. MATLAB® is used to interact with the FEMM software package through ActiveX framework, allowing for a detailed calculation of the electromagnetic properties of the machines examined.
Optical Properties of ZnO Nanocrystallines Photovoltaic UV Detector
Authors: Suhail Abdullah M. , Ahmed Sudad S. , Ibrahim Omar A. , Emad Faten
Published: August 2014

Zinc Oxide (ZnO) /porous-silicon photovoltaic device was fabricated to detect fast ultraviolet (UV) radiation pulses. The photovoltaic UV detector, based on the deposition of the ZnO wide-band gap semiconductor material on nanospikes silicon layer to form a heterojunction, has fast response time to the UV pulses. The current voltage characteristic, the capacitance variation with the applied voltage and the ideality factor of the heterojunction were studied. The operation of the detector under the reverse bias of-2 volts has successfully detected an ultra-fast nitrogen laser pulses at 385 (nm).
Molecular Dynamics Simulations of Piezoelectric Materials for Energy Harvesting Applications
Authors: Haskins Justin B. , Kinaci Alper , Çağın Tahir
Published: August 2014

The previously proposed polarizable charge equilibrium (PQEq) force field model is parameterized for studying lead titanate (PT), lead zirconate (PZ), and their alloys: lead zirconate titanate (PZT). Several molecular dynamics (MD) simulations are performed to assess the degree of accuracy of the model. The phase transition temperatures, which are generally inaccurate in MD, are shown to be similar to experimental measurements. Also, the calculation of the ferroelectric hysteretic behavior, including the spontaneous polarization, saturated polarization and coercive fields, with extended MD is shown to give a qualitatively correct comparison between PT and PZT. The accuracy of the electronic properties in PQEq leads to direct application to a range of interesting problems such as enhanced properties of piezo- and ferro-electric nanostructures and the kinetics of domain walls in these materials.
Three-Dimensional Magnetic Field Analysis for Local Induction Heating of Steel Sheet by Using Magnetic Flux Concentration Plate
Authors: Kai Yuichiro , Tsuchida Yuji , Todaka Takashi , Enokizono Masato
Published: August 2014

In general, the magnetic properties of electrical steel sheets are strongly influenced by mechanical stress. We have reported the measurement results of vector magnetic properties of a non-oriented electrical steel sheet under stress conditions. From these results, it is possible to control the vector magnetic property by applying local mechanical stress. Therefore, we next focus on an induction heating technique that applies mechanical stress in a non-oriented electrical steel sheet. It is very important to control the eddy current distribution inside the non-oriented electrical steel sheet. This paper presents a magnetic flux concentration plate structure to control the eddy current in steel sheets by using an induction heating technique. The magnetic flux concentration plate structure is investigated in a three-dimensional magnetic field analysis by the finite element method.
Pre-release detection of a biocontrol agent: combining independent and public DNA sequences to identify the first North American record of Aulacidea pilosellae (Hymenoptera: Cynipidae)
Authors: Moffat Chandra E. , Smith M. Alex
Published: August 2014

Here we report the first North American detection of the gall wasp Aulacidea pilosellae Kieffer (Hymenoptera: Cynipidae), native to Central Europe and a promising candidate biological control agent for invasive hawkweeds (Pilosella Vaillant, Asteraceae) in North America. This occurrence was discovered through the intersection of (i) publically available DNA barcode data and (ii) DNA sequencing of a biocontrol agent before its release. COI DNA sequences of A. pilosellae collected in Central Europe were compared with publically available DNA sequence records. Despite the presence of other Aulacidea Ashmead in the database, the most similar sequence to the European A. pilosellae was an as yet unidentified specimen collected in the Ottawa Valley of eastern Ontario, Canada. Subsequent sequencing of a second gene region (28S-D2) of the Ottawa Valley specimen yielded an identical DNA sequence to the European A. pilosellae, confirming the presence of this species in Ontario. This note highlights the potential synergy that can result from making DNA barcode data publically available before formal taxonomic identification, and a new benefit of incorporating DNA sequencing of standardised markers into biological control programmes.
Efficacy of BioXtra Spray and Mouthwash in Patients with Radiation-induced Xerostomia: A Randomized Clinical Trial
Authors: Bakhshi Mahin , Manifar Soheila , Azizi Nemat , Shabestari Samira Basir , Mardi Abbas Hossein , Shirinbak Iman , Mehdipour Aida
Published: August 2014

Aim

Xerostomia is an important complication following radiotherapy for head and neck regions producing serious discomfort for patients. Symptomatic treatments for the disease include strict oral hygiene and use of artificial saliva substitutes. The present study compared the efficacy of BioXtra spray and mouthwash in the relief of radiotherapy-induced xerostomia in patients referred to Imam Khomeini Hospital, Tehran University of Medical Sciences.

Materials and methods

In a cross-over randomized clinical trial, BioXtra spray and mouth wash were used by 20 patients for 2 weeks with a 1 week wash-out period. The ease of application and the patients’ acceptance of the products were obtained using 100 mm visual analog scale (VAS) and dichotomous scales. We used SPSS version. 18.0 to analyze our data considering level of significance less than 0.05.

Results

Both forms of BioXtra showed similar effect in reducing oral dryness and its complications. The mean VAS was 33.2 for spray and 34.5 for mouthwash. Majority of our patients reported improvements in xerostomia after using spray (85%) and mouthwash (70%), respectively. The patients’ acceptance of both modalities was similar and they showed equal tendency to continue the treatments. No significant differences in symptoms relief as well as judgment of the regimens were found between groups.

Conclusion

BioXtra spray and mouthwash are similarly effective in reducing the symptoms of postradiotherapy xerostomia.

How to cite this article

Bakhshi M, Manifar S, Azizi N, Shabestari SB, Mardi AH, Shirinbak I, Mehdipour A. Efficacy of BioXtra Spray and Mouthwash in Patients with Radiationinduced Xerostomia: A Randomized Clinical Trial. Int J Experiment Dent Sci 2014;3(1):19-23.
Flexural Strength of E-glass-reinforced PMMA
Authors: Mathew Merin , Shenoy Kamalakanth , Ravishankar KS
Published: August 2014

Background

Poly (methyl 2-methylpropenoate) (PMMA) is one of the most widely accepted biomaterials due to its acceptable advantageous but the limitations associated with these materials make them far from being ideal. So, the present study is to achieve desirable flexural strength by reinforcing PMMA with E-glass fiber.

Aim

Determination of flexural strength of PMMA by varying the weight percentage of glass fiber (2.5 wt%, 5 wt%, 10 wt%), and by varying the aspect ratio (3 mm/20 µm, 6 mm/20 µm, 12 mm/20 µm) of glass fiber.

Materials and methods

Specimens prepared using a standard rectangular mold of 62 mm length, 10 mm breadth and 2.5 mm thickness. A total of 60 samples prepared (6 samples in each group) polymer—monomer ratio 2.4:1 by weight used to prepare samples. Flexural strength is tested using universal testing machine Instron. The microstructural analysis using scanning electron microscopy performed in order to understand the fiber matrix bonding. Detailed statistical analysis done by one-way ANOVA.

Results

Highest flexural strength is observed for the PMMA reinforced with 6 mm/20 µm fiber 2.5 wt%.

How to cite this article

Mathew M, Shenoy K, Ravishankar KS. Flexural Strength of E-glass-reinforced PMMA. Int J Experiment Dent Sci 2014;3(1):24-28.
A two-channel, tunable diode laser-based hygrometer for measurement of water vapor and cirrus cloud ice water content in the upper troposphere and lower stratosphere
Authors: Thornberry T. D. , Rollins A. W. , Gao R. S. , Watts L. A. , Ciciora S. J. , McLaughlin R. J. , Fahey D. W.
Published: August 2014

Abstract. The recently developed NOAA Water instrument is a two-channel, closed-path, tunable diode laser absorption spectrometer designed for the measurement of water vapor and enhanced total water (vapor + inertially enhanced condensed-phase) in the upper troposphere/lower stratosphere from the NASA Global Hawk unmanned aircraft system (UAS) or other high-altitude research aircraft. The instrument utilizes wavelength-modulated spectroscopy with second harmonic detection near 2694 nm to achieve high precision with a 79 cm double-pass optical path. The detection cells are operated under constant temperature, pressure and flow conditions to maintain a constant sensitivity to H2O independent of the ambient sampling environment. An on-board calibration system is used to perform periodic in situ calibrations to verify the stability of the instrument sensitivity during flight. For the water vapor channel, ambient air is sampled perpendicular to the flow past the aircraft in order to reject cloud particles, while the total water channel uses a heated, forward-facing inlet to sample both water vapor and cloud particles. The total water inlet operates subisokinetically, thereby inertially enhancing cloud particle number in the sample flow and affording increased cloud water content sensitivity. The NOAA Water instrument was flown for the first time during the second deployment of the Airborne Tropical TRopopause EXperiment (ATTREX) in February–March 2013 on board the Global Hawk UAS. The instrument demonstrated a typical in-flight precision (1 s, 1σ) of better than 0.17 parts per million (ppm, 10−6 mol mol−1), with an overall H2O vapor measurement uncertainty of 5% ± 0.23 ppm. The inertial enhancement for cirrus cloud particle sampling under ATTREX flight conditions ranged from 33–48 for ice particles larger than 8 μm in diameter, depending primarily on aircraft altitude. The resulting ice water content detection limit (2σ) was 0.023–0.013 ppm, corresponding to approximately 2 μg m−3, with an estimated overall uncertainty of 20%.
Ozone and temperature decadal trends in the stratosphere, mesosphere and lower thermosphere, based on measurements from SABER on TIMED
Authors: Huang F. T. , Mayr H. G. , Russell J. M. , Mlynczak M. G.
Published: August 2014

Abstract. We have derived ozone and temperature trends from years 2002 through 2012, from 20 to 100 km altitude, and 48° S to 48° N latitude, based on measurements from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) satellite. For the first time, trends of ozone and temperature measured at the same times and locations are obtained, and their correlations should provide useful information about the relative importance of photochemistry versus dynamics over the longer term. We are not aware of comparable results covering this time period and spatial extent. For stratospheric ozone, until the late 1990s, previous studies found negative trends (decreasing amounts). In recent years, some empirical and modeling studies have shown the occurrence of a turnaround in the decreasing ozone, possibly beginning in the late 1990s, suggesting that the stratospheric ozone trend is leveling off or even turning positive. Our global results add more definitive evidence, expand the coverage, and show that at mid-latitudes (north and south) in the stratosphere, the ozone trends are indeed positive, with ozone having increased by a few percent from 2002 through 2012. However, in the tropics, we find negative ozone trends between 25 and 50 km. For stratospheric temperatures, the trends are mostly negatively correlated to the ozone trends. The temperature trends are positive in the tropics between 30 and 40 km, and between 20 and 25 km, at approximately 24° N and at 24° S latitude. The stratospheric temperature trends are otherwise mostly negative. In the mesosphere, the ozone trends are mostly flat, with suggestions of small positive trends at lower latitudes. The temperature trends in this region are mostly negative, showing decreases of up to ~ −3 K decade−1. In the lower thermosphere (between ~ 85 and 100 km), ozone and temperature trends are both negative. The ozone trend can approach ~ −10% decade−1, and the temperature trend can approach ~ −3 K decade−1. Aside from trends, these patterns of ozone–temperature correlations are consistent with previous studies of ozone and temperature perturbations such as the quasi-biennial (QBO) and semiannual (SAO) oscillations, and add confidence to the results.
Controls and characteristics of variability in soil moisture and groundwater in a headwater catchment
Authors: McMillan H. K. , Srinivasan M. S.
Published: August 2014

Abstract. This paper presents experimental results from a new headwater research catchment in New Zealand. We made distributed measurements of streamflow, soil moisture and groundwater levels, sampling across a range of aspects, hillslope positions, distances from stream and depths. Our aim was to assess the controls, types and implications of spatial and temporal variability in surface and groundwaters. We found that temporal variability is strongly controlled by the seasonal cycle, for both soil moisture and water table, and for both the mean and extremes of the distributions. The standard deviation of both soil moisture and groundwater values calculated per timestep is larger in winter than in summer, and standard deviations typically peak during rainfall events due to partial saturation of the catchment. Controls on the spatial variability differed between the water stores. Aspect had a strong control on groundwater but not on soil moisture, distance from stream controlled both soil moisture and groundwater. The depth of the soil moisture sensor had little impact in terms of mean water content, but a strong impact on the extreme values, i.e. saturation. Co-measurement of soil moisture and water table level variability allowed us to identify variability components that differed between these water stores e.g. patterns of strong response in soil water content were not the same for groundwater level, and those that were consistent e.g. vertical infiltration of summer rainfall through upper and lower soil depths, or rising near-stream water tables through shallow wells to lower soil depths. Signatures of variability were observed in the streamflow series, showing that understanding variability is important for hydrological prediction. Total catchment variability is composed of multiple variability sources. The dominant variability type changes with catchment wetness conditions according to which water stores are active, and in particular those which are close to a threshold such as field capacity or saturation. Our results suggest that the integrative processes that create emergent catchment behaviour should be understood as the sum of these multiple, time varying components.
Global-scale object detection using satellite imagery
Authors: Hamid R. , O'Hara S. , Tabb M.
Published: August 2014

Abstract. In recent years, there has been a substantial increase in the availability of high-resolution commercial satellite imagery, enabling a variety of new remote-sensing applications. One of the main challenges for these applications is the accurate and efficient extraction of semantic information from satellite imagery. In this work, we investigate an important instance of this class of challenges which involves automatic detection of multiple objects in satellite images. We present a system for large-scale object training and detection, leveraging recent advances in feature representation and aggregation within the bag-of-words paradigm. Given the scale of the problem, one of the key challenges in learning object detectors is the acquisition and curation of labeled training data. We present a crowd-sourcing based framework that allows efficient acquisition of labeled training data, along with an iterative mechanism to overcome the label noise introduced by the crowd during the labeling process. To show the competence of the presented scheme, we show detection results over several object-classes using training data captured from close to 200 cities and tested over multiple geographic locations.
A Fast Recognition Algorithm for Detection of Foreign 3D Objects on a Runway
Authors: Kniaz V. V.
Published: August 2014

Abstract. !The systems for detection of foreign objects on a runway during the landing of an aircraft are highly demanded. Such systems could be installed in the airport or could be mounted on the board of an aircraft. This work is focused on a fast foreign object recognition algorithm for an onboard foreign object detection system. The algorithm is based on 3D object minimal boundary extraction. The boundary is estimated through an iterative process of minimization of a difference between a pair of orthophotos. During the landing an onboard camera produces a sequence of images from which a number of stereo pair could be extracted. For each frame the runway lines are automatically detected and the external orientation of the camera relative to the runway is estimated. Using external orientation parameters the runway region is projected on an orthophoto to the runway plane. The difference of orthophotos shows the objects that doesn't coincide with the runway plane. After that the position of the foreign object relative to the runway plane and its minimal 3D boundary could be calculated. The minimal 3D boundary for each object is estimated by projection of a runway region on a modified model of the runway. The extracted boundary is used for an automatic recognition of a foreign object from the predefined bank of 3D models.
Photogrammetric Technique for Timber Stack Volume Contol
Authors: Knyaz V. A. , Maksimov A. A.
Published: August 2014

Abstract. The problem of accurate log volume measurement is a very important, especially in case of seaport volume control where logs are put in a huge stack of hundred meters length and a time for volume control is strongly restricted. Current technology of volume control use manual means such as measuring tape, so the process of measurement is rather inaccurate and time consuming. To estimate the volume of timber stack its frontal area is measured and some control parts of a stack are used for stacking coefficient (wood density in a stack) determination. Non-contact vision based technique is proposed for manual measurements substituting. The developed methods are implemented in portable photogrammetric system for stack parameters measuring and documenting.
Morphological operation based dense houses extraction from DSM
Authors: Li Y. , Zhu L. , Tachibana K. , Shimamura H.
Published: August 2014

Abstract. This paper presents a method of reshaping and extraction of markers and masks of the dense houses from the DSM based on mathematical morphology (MM). Houses in a digital surface model (DSM) are almost joined together in high-density housing areas, and most segmentation methods cannot completely separate them. We propose to label the markers of the buildings firstly and segment them into masks by watershed then. To avoid detecting more than one marker for a house or no marker at all due to its higher neighbour, the DSM is morphologically reshaped. It is carried out by a MM operation using the certain disk shape SE of the similar size to the houses. The sizes of the houses need to be estimated before reshaping. A granulometry generated by opening-by-reconstruction to the NDSM is proposed to detect the scales of the off-terrain objects. It is a histogram of the global volume of the top hats of the convex objects in the continuous scales. The obvious step change in the profile means that there are many objects of similar sizes occur at this scale. In reshaping procedure, the slices of the object are derived by morphological filtering at the detected continuous scales and reconstructed in pile as the dome. The markers are detected on the basis of the domes.
Automatic urban 3D building reconstruction from multi-ray photogrammetry
Authors: McClune A. P. , Miller P. E. , Mills J. P. , Holland D.
Published: August 2014

Abstract. Over the last 20 years the use of, and demand for, three dimensional (3D) building models has meant there has been a vast amount of research conducted in automating the extraction and reconstruction of these models from airborne sensors. Whilst many different approaches have been suggested, full automation is yet to be achieved and research has suggested that the combination of data from multiple sources is required in order to achieve this. Developments in digital photogrammetry have delivered improvements in spatial resolution whilst higher image overlap to increase the number of pixel correspondents between images, giving the name multi-ray photogrammetry, has improved the resolution and quality of its by-products. In this paper the extraction of roof geometry from multiray photogrammetry will be covered, which underpins 3D building reconstruction. Using orthophotos, roof vertices are extracted using the Canny edge detector. Roof planes are detected from digital surface models (DSM) by extracting information from 2D cross sections and measuring height differences. To eliminate overhanging vegetation, the segmentation of trees is investigated by calculating the characteristics of a point within a local neighbourhood of the photogrammetric point cloud. The results highlight the complementary nature of these information sources, and a methodology for integration and reconstruction of roof geometry is proposed.
Photogrammetric DSM denoising
Authors: Nex F. , Gerke M.
Published: August 2014

Abstract. Image matching techniques can nowadays provide very dense point clouds and they are often considered a valid alternative to LiDAR point cloud. However, photogrammetric point clouds are often characterized by a higher level of random noise compared to LiDAR data and by the presence of large outliers. These problems constitute a limitation in the practical use of photogrammetric data for many applications but an effective way to enhance the generated point cloud has still to be found. In this paper we concentrate on the restoration of Digital Surface Models (DSM), computed from dense image matching point clouds. A photogrammetric DSM, i.e. a 2.5D representation of the surface is still one of the major products derived from point clouds. Four different algorithms devoted to DSM denoising are presented: a standard median filter approach, a bilateral filter, a variational approach (TGV: Total Generalized Variation), as well as a newly developed algorithm, which is embedded into a Markov Random Field (MRF) framework and optimized through graph-cuts. The ability of each algorithm to recover the original DSM has been quantitatively evaluated. To do that, a synthetic DSM has been generated and different typologies of noise have been added to mimic the typical errors of photogrammetric DSMs. The evaluation reveals that standard filters like median and edge preserving smoothing through a bilateral filter approach cannot sufficiently remove typical errors occurring in a photogrammetric DSM. The TGV-based approach much better removes random noise, but large areas with outliers still remain. Our own method which explicitly models the degradation properties of those DSM outperforms the others in all aspects.
Building Roof Component Extraction from Panchromatic Satellite Images Using a Clustering-Based Method
Authors: Partovi T. , Bahmanyar R. , Krauß T. , Reinartz P.
Published: August 2014

Abstract. Developing fully automatic systems is still an active research topic in 3D building model reconstruction. While a general solution to the building reconstruction problem relies on collecting and grouping the modeling cues (e.g., lines, corners, planes) from Digital Surface Model (DSM) data, failure in finding the cues due to noise in the DSM and the object complexities is a big challenge. In this paper, we introduce a clustering-based method for cue discovery from Pan-chromatic satellite images which reduces the dependencies of the reconstruction techniques on DSM data. Experimental results show that the proposed method is not only able to effectively refine building masks by discriminating building boundaries from nearby clutter, but also is able to determine the roof types (e.g., pitched, flat). The latter, allows to establish a reconstruction method to reduces the search effort and the failure probability regions in finding a particular cue by leading the system to an appropriate area.
Automatic Building Extraction From LIDAR Data Covering Complex Urban Scenes
Authors: Awrangjeb M. , Lu G. , Fraser C.
Published: August 2014

Abstract. This paper presents a new method for segmentation of LIDAR point cloud data for automatic building extraction. Using the ground height from a DEM (Digital Elevation Model), the non-ground points (mainly buildings and trees) are separated from the ground points. Points on walls are removed from the set of non-ground points by applying the following two approaches: If a plane fitted at a point and its neighbourhood is perpendicular to a fictitious horizontal plane, then this point is designated as a wall point. When LIDAR points are projected on a dense grid, points within a narrow area close to an imaginary vertical line on the wall should fall into the same grid cell. If three or more points fall into the same cell, then the intermediate points are removed as wall points. The remaining non-ground points are then divided into clusters based on height and local neighbourhood. One or more clusters are initialised based on the maximum height of the points and then each cluster is extended by applying height and neighbourhood constraints. Planar roof segments are extracted from each cluster of points following a region-growing technique. Planes are initialised using coplanar points as seed points and then grown using plane compatibility tests. If the estimated height of a point is similar to its LIDAR generated height, or if its normal distance to a plane is within a predefined limit, then the point is added to the plane. Once all the planar segments are extracted, the common points between the neghbouring planes are assigned to the appropriate planes based on the plane intersection line, locality and the angle between the normal at a common point and the corresponding plane. A rule-based procedure is applied to remove tree planes which are small in size and randomly oriented. The neighbouring planes are then merged to obtain individual building boundaries, which are regularised based on long line segments. Experimental results on ISPRS benchmark data sets show that the proposed method offers higher building detection and roof plane extraction rates than many existing methods, especially in complex urban scenes.
Integration of Image Data for Refining Building Boundaries Derived from Point Clouds
Authors: Perera S. N. , Hetti Arachchige N. , Schneider D.
Published: August 2014

Abstract. Geometrically and topologically correct 3D building models are required to satisfy with new demands such as 3D cadastre, map updating, and decision making. More attention on building reconstruction has been paid using Airborne Laser Scanning (ALS) point cloud data. The planimetric accuracy of roof outlines, including step-edges is questionable in building models derived from only point clouds. This paper presents a new approach for the detection of accurate building boundaries by merging point clouds acquired by ALS and aerial photographs. It comprises two major parts: reconstruction of initial roof models from point clouds only, and refinement of their boundaries. A shortest closed circle (graph) analysis method is employed to generate building models in the first step. Having the advantages of high reliability, this method provides reconstruction without prior knowledge of primitive building types even when complex height jumps and various types of building roof are available. The accurate position of boundaries of the initial models is determined by the integration of the edges extracted from aerial photographs. In this process, scene constraints defined based on the initial roof models are introduced as the initial roof models are representing explicit unambiguous geometries about the scene. Experiments were conducted using the ISPRS benchmark test data. Based on test results, we show that the proposed approach can reconstruct 3D building models with higher geometrical (planimetry and vertical) and topological accuracy.