Surface quality prediction model of nano-composite ceramics in ultrasonic vibration-assisted ELID mirror grinding

Energy Technology Data Exchange (ETDEWEB)

Zhao, Bo; Chen, Fan; Jia, Xiao-feng; Zhao, Chong-yang; Wang, Xiao-bo [Henan Polytechnic University, Jiaozuo (China)

2017-04-15

Ultrasonic vibration-assisted Electrolytic in-process dressing (ELID) grinding is a highly efficient and highly precise machining method. The surface quality prediction model in ultrasonic vibration-assisted ELID mirror grinding was studied. First, the interaction between grits and workpiece surface was analyzed according to kinematic mechanics, and the surface roughness model was developed. The variations in surface roughness under different parameters was subsequently calculated and analyzed by MATLAB. Results indicate that compared with the ordinary ELID grinding, ultrasonic vibration-assisted ELID grinding is superior, because it has more stable and better surface quality and has an improved range of ductile machining.

Dome shaped features on Europa's surface

Science.gov (United States)

1997-01-01

The Solid State Imaging system aboard the spacecraft Galileo took this image of the surface of Europa on February 20, 1997 during its sixth orbit around Jupiter. The image is located near 16 North, 268 West; illumination is from the lower-right. The area covered is approximately 48 miles (80 kilometers) by 56 miles (95 kilometers) across. North is toward the top of the image.This image reveals that the icy surface of Europa has been disrupted by ridges and faults numerous times during its past. These ridges have themselves been disrupted by the localized formation of domes and other features that may be indicative of thermal upwelling of water from beneath the crust. These features provide strong evidence for the presence of subsurface liquid during Europa's recent past.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Surface Improvement of Shafts by Turn-Assisted Deep Cold Rolling Process

Directory of Open Access Journals (Sweden)

Prabhu Raghavendra

2016-01-01

Full Text Available It is well recognized that mechanical surface enhancement methods can significantly improve the characteristics of highly-stressed metallic components. Deep cold rolling is one of such technique which is particularly attractive since it is possible to generate, near the surface, deep compressive residual stresses and work hardened layers while retaining a relatively smooth surface finish. In this paper, the effect of turn-assisted deep cold rolling on AISI 4140 steel is examined, with emphasis on the residual stress state. Based on the X-ray diffraction measurements, it is found that turn-assisted deep cold rolling can be quite effective in retarding the initiation and initial propagation of fatigue cracks in AISI 4140 steel.

Floor Covering and Surface Identification for Assistive Mobile Robotic Real-Time Room Localization Application

Directory of Open Access Journals (Sweden)

Michael Gillham

2013-12-01

Full Text Available Assistive robotic applications require systems capable of interaction in the human world, a workspace which is highly dynamic and not always predictable. Mobile assistive devices face the additional and complex problem of when and if intervention should occur; therefore before any trajectory assistance is given, the robotic device must know where it is in real-time, without unnecessary disruption or delay to the user requirements. In this paper, we demonstrate a novel robust method for determining room identification from floor features in a real-time computational frame for autonomous and assistive robotics in the human environment. We utilize two inexpensive sensors: an optical mouse sensor for straightforward and rapid, texture or pattern sampling, and a four color photodiode light sensor for fast color determination. We show how data relating floor texture and color obtained from typical dynamic human environments, using these two sensors, compares favorably with data obtained from a standard webcam. We show that suitable data can be extracted from these two sensors at a rate 16 times faster than a standard webcam, and that these data are in a form which can be rapidly processed using readily available classification techniques, suitable for real-time system application. We achieved a 95% correct classification accuracy identifying 133 rooms’ flooring from 35 classes, suitable for fast coarse global room localization application, boundary crossing detection, and additionally some degree of surface type identification.

Effect of microwave-assisted heating on chalcopyrite leaching of kinetics, interface temperature and surface energy

Directory of Open Access Journals (Sweden)

Tong Wen

Full Text Available The microwave-assisted leaching was a new approach to intensify the copper recovery from chalcopyrite by hydrometallurgy. In this work, the effect of microwave-assisted heating on chalcopyrite leaching of kinetics, interfacial reaction temperature and surface energy were investigated. The activation energy of chalcopyrite leaching was affected indistinctively by the microwave-assisted heating (39.1 kJ/mol compared with the conventional heating (43.9 kJ/mol. However, the boiling point of the leaching system increased through microwave-assisted heating. Because of the improved boiling point and the selective heating of microwave, the interfacial reaction temperature increased significantly, which gave rise to the increase of the leaching recovery of copper. Moreover, the surface energy of the chalcopyrite through microwave-assisted heating was also enhanced, which was beneficial to strengthen the leaching of chalcopyrite. Keywords: Microwave-assisted heating, Chalcopyrite, Leaching kinetics, Interface temperature, Surface energy

Surface-Assisted Dynamic Search Processes.

Science.gov (United States)

Shin, Jaeoh; Kolomeisky, Anatoly B

2018-03-01

Many chemical and biological systems exhibit intermittent search phenomena when participating particles alternate between dynamic regimes with different dimensionalities. Here we investigate theoretically a dynamic search process of finding a small target on a two-dimensional surface starting from a bulk solution, which is an example of such an intermittent search process. Both continuum and discrete-state stochastic descriptions are developed. It is found that depending on the scanning length λ, which describes the area visited by the reacting molecule during one search cycle, the system can exhibit three different search regimes: (i) For small λ values, the reactant finds the target mostly via three-dimensional bulk diffusion; (ii) for large λ values, the reactant molecule associates to the target mostly via surface diffusion; and (iii) for intermediate λ values, the reactant reaches the target via a combination of three-dimensional and two-dimensional search cycles. Our analysis also shows that the mean search times have different scalings as a function of the size of the surface segment depending on the nature of the dynamic search regime. Search dynamics are also sensitive to the position of the target for large scanning lengths. In addition, it is argued that the continuum description underestimates mean search times and does not always correctly describe the most optimal conditions for the surface-assisted dynamic processes. The importance of our findings for real natural systems is discussed.

The Evaluation of Surface Integrity During Machining of Inconel 718 with Various Laser Assistance Strategies

Directory of Open Access Journals (Sweden)

Wojciechowski Szymon

2017-01-01

Full Text Available The paper is focused on the evaluation of surface integrity formed during turning of Inconel 718 with the application of various laser assistance strategies. The primary objective of the work was to determine the relations between the applied machining strategy and the obtained surface integrity, in order to select the effective cutting conditions allowing the obtainment of high surface quality. The carried out experiment included the machining of Inconel 718 in the conventional turning conditions, as well as during the continuous laser assisted machining and sequential laser assistance. The surface integrity was evaluated by the measurements of machined surface topographies, microstructures and the microhardness. Results revealed that surface integrity of Inconel 718 is strongly affected by the selected machining strategy. The significant improvement of the surface roughness formed during machining of Inconel 718, can be reached by the application of simultaneous laser heating and cutting (LAM.

A Novel Feature Optimization for Wearable Human-Computer Interfaces Using Surface Electromyography Sensors

Directory of Open Access Journals (Sweden)

Han Sun

2018-03-01

Full Text Available The novel human-computer interface (HCI using bioelectrical signals as input is a valuable tool to improve the lives of people with disabilities. In this paper, surface electromyography (sEMG signals induced by four classes of wrist movements were acquired from four sites on the lower arm with our designed system. Forty-two features were extracted from the time, frequency and time-frequency domains. Optimal channels were determined from single-channel classification performance rank. The optimal-feature selection was according to a modified entropy criteria (EC and Fisher discrimination (FD criteria. The feature selection results were evaluated by four different classifiers, and compared with other conventional feature subsets. In online tests, the wearable system acquired real-time sEMG signals. The selected features and trained classifier model were used to control a telecar through four different paradigms in a designed environment with simple obstacles. Performance was evaluated based on travel time (TT and recognition rate (RR. The results of hardware evaluation verified the feasibility of our acquisition systems, and ensured signal quality. Single-channel analysis results indicated that the channel located on the extensor carpi ulnaris (ECU performed best with mean classification accuracy of 97.45% for all movement’s pairs. Channels placed on ECU and the extensor carpi radialis (ECR were selected according to the accuracy rank. Experimental results showed that the proposed FD method was better than other feature selection methods and single-type features. The combination of FD and random forest (RF performed best in offline analysis, with 96.77% multi-class RR. Online results illustrated that the state-machine paradigm with a 125 ms window had the highest maneuverability and was closest to real-life control. Subjects could accomplish online sessions by three sEMG-based paradigms, with average times of 46.02, 49.06 and 48.08 s

Plasma assisted surface coating/modification processes: An emerging technology

Science.gov (United States)

Spalvins, T.

1986-01-01

A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation). These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

Plasma assisted surface coating/modification processes - An emerging technology

Science.gov (United States)

Spalvins, T.

1987-01-01

A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation. These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

Surface modification of titanium hydride with epoxy resin via microwave-assisted ball milling

International Nuclear Information System (INIS)

Ning, Rong; Chen, Ding; Zhang, Qianxia; Bian, Zhibing; Dai, Haixiong; Zhang, Chi

2014-01-01

Highlights: • TiH 2 was modified with epoxy resin by microwave-assisted ball milling. • The epoxy ring was opened under the coupling effect of microwave and ball milling. • Microwave-assisted ball milling improved the compatibility of TiH 2 with epoxy. - Abstract: Surface modification of titanium hydride with epoxy resin was carried out via microwave-assisted ball milling and the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and Fourier transform infrared spectroscopy (FT-IR). A sedimentation test was performed to investigate the compatibility of the modified nano titanium hydride with the epoxy resin. The results show that the epoxy resin molecules were grafted on the surface of nano titanium hydride particles during the microwave-assisted ball milling process, which led to the improvement of compatibility between the nanoparticles and epoxy resin. According to the FT-IR, the grafting site was likely to be located around the epoxy group due to the fact that the epoxy ring was opened. However, compared with microwave-assisted ball milling, the conventional ball milling could not realize the surface modification, indicating that the coupling effect of mechanical force and microwave played a key role during the process

The Identification, Implementation, and Evaluation of Critical User Interface Design Features of Computer-Assisted Instruction Programs in Mathematics for Students with Learning Disabilities

Science.gov (United States)

Seo, You-Jin; Woo, Honguk

2010-01-01

Critical user interface design features of computer-assisted instruction programs in mathematics for students with learning disabilities and corresponding implementation guidelines were identified in this study. Based on the identified features and guidelines, a multimedia computer-assisted instruction program, "Math Explorer", which delivers…

Analysis of iris surface features in populations of diverse ancestry

Science.gov (United States)

Edwards, Melissa; Cha, David; Krithika, S.; Johnson, Monique; Parra, Esteban J.

2016-01-01

There are many textural elements that can be found in the human eye, including Fuchs’ crypts, Wolfflin nodules, pigment spots, contraction furrows and conjunctival melanosis. Although iris surface features have been well-studied in populations of European ancestry, the worldwide distribution of these traits is poorly understood. In this paper, we develop a new method of characterizing iris features from photographs of the iris. We then apply this method to a diverse sample of East Asian, European and South Asian ancestry. All five iris features showed significant differences in frequency between the three populations, indicating that iris features are largely population dependent. Although none of the features were correlated with each other in the East and South Asian groups, Fuchs’ crypts were significantly correlated with contraction furrows and pigment spots and contraction furrows were significantly associated with pigment spots in the European group. The genetic marker SEMA3A rs10235789 was significantly associated with Fuchs’ crypt grade in the European, East Asian and South Asian samples and a borderline association between TRAF3IP1 rs3739070 and contraction furrow grade was found in the European sample. The study of iris surface features in diverse populations may provide valuable information of forensic, biomedical and ophthalmological interest. PMID:26909168

Design of Sail-Assisted Unmanned Surface Vehicle Intelligent Control System

OpenAIRE

Ma, Yong; Zhao, Yujiao; Diao, Jiantao; Gan, Langxiong; Bi, Huaxiong; Zhao, Jingming

2016-01-01

To achieve the wind sail-assisted function of the unmanned surface vehicle (USV), this work focuses on the design problems of the sail-assisted USV intelligent control systems (SUICS) and illustrates the implementation process of the SUICS. The SUICS consists of the communication system, the sensor system, the PC platform, and the lower machine platform. To make full use of the wind energy, in the SUICS, we propose the sail angle of attack automatic adjustment (Sail_4A) algorithm and present ...

Characterisation and Testing of Multifunctional Surfaces

DEFF Research Database (Denmark)

Godi, Alessandro

the acronym stands for multifunctional. Produced by hard-turning followed by a highly controllable Robot Assisted Polishing process, MUFU surfaces feature reservoirs for providing extra-lubrication between the contacting parts as well as uppermost flat regions for ensuring the bearing capability...... filtered and aligned roughness profile that would be unrealistically distorted if current practice methods were used. Once an aligned profile is obtained, a further operation is introduced: feature separation. The surface features are separated with a newly developed algorithm and analysed independently...

Polarization controlled deep sub-wavelength periodic features written by femtosecond laser on nanodiamond thin film surface

Energy Technology Data Exchange (ETDEWEB)

Kumar Kuntumalla, Mohan; Srikanth, Vadali V. S. S., E-mail: vvsssse@uohyd.ernet.in [School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046 (India); Rajamudili, Kuladeep; Rao Desai, Narayana [School of Physics, University of Hyderabad, Hyderabad 500046 (India)

2014-04-21

Deep sub-wavelength (Λ/λ = ∼0.22) periodic features are induced uniformly on a nanodiamond (ND) thin film surface using femtosecond (fs) laser irradiation (pulse duration = ∼110 fs and central wavelength of ∼800 nm). The topography of the surface features is controlled by the laser polarization. Orientation of features is perpendicular to laser polarization. Periodicity (spatial periodicity of < λ/4) of the surface features is less than the laser wavelength. This work gives an experimental proof of polarization controlled surface plasmon-fs laser coupling mechanism prompting the interaction between fs laser and solid matter (here ND thin film) which in turn is resulting in the periodic surface features. Scanning electron microscopy in conjunction with micro Raman scattering, X-ray diffraction, and atomic force microscopy are carried out to extract surface morphology and phase information of the laser irradiated regions. This work demonstrates an easy and efficient surface fabrication technique.

Touching Textured Surfaces: Cells in Somatosensory Cortex Respond Both to Finger Movement and to Surface Features

Science.gov (United States)

Darian-Smith, Ian; Sugitani, Michio; Heywood, John; Karita, Keishiro; Goodwin, Antony

1982-11-01

Single neurons in Brodmann's areas 3b and 1 of the macaque postcentral gyrus discharge when the monkey rubs the contralateral finger pads across a textured surface. Both the finger movement and the spatial pattern of the surface determine this discharge in each cell. The spatial features of the surface are represented unambiguously only in the responses of populations of these neurons, and not in the responses of the constituent cells.

Accurate measurement of surface areas of anatomical structures by computer-assisted triangulation of computed tomography images

Energy Technology Data Exchange (ETDEWEB)

Allardice, J.T.; Jacomb-Hood, J.; Abulafi, A.M.; Williams, N.S. (Royal London Hospital (United Kingdom)); Cookson, J.; Dykes, E.; Holman, J. (London Hospital Medical College (United Kingdom))

1993-05-01

There is a need for accurate surface area measurement of internal anatomical structures in order to define light dosimetry in adjunctive intraoperative photodynamic therapy (AIOPDT). The authors investigated whether computer-assisted triangulation of serial sections generated by computed tomography (CT) scanning can give an accurate assessment of the surface area of the walls of the true pelvis after anterior resection and before colorectal anastomosis. They show that the technique of paper density tessellation is an acceptable method of measuring the surface areas of phantom objects, with a maximum error of 0.5%, and is used as the gold standard. Computer-assisted triangulation of CT images of standard geometric objects and accurately-constructed pelvic phantoms gives a surface area assessment with a maximum error of 2.5% compared with the gold standard. The CT images of 20 patients' pelves have been analysed by computer-assisted triangulation and this shows the surface area of the walls varies from 143 cm[sup 2] to 392 cm[sup 2]. (Author).

Airborne laser: a tool to study landscape surface features

International Nuclear Information System (INIS)

Ritchie, J.C.; Jackson, T.J.; Everitt, J.H.; Escobar, D.E.; Murphey, J.B.; Grissinger, E.H.

1992-01-01

Landscape surface features related to erosion and hydrology were measured using an airborne laser profiler. The airborne laser profiler made 4,000 measurements per second with a recording accuracy of 5 cm (1.9 inches) on a single measurement. Digital data from the laser are recorded and analyzed with a personal computer. These airborne laser profiles provide information on surface landscape features. Topography and canopy heights, cover, and distribution of natural vegetation were determined in studies in South Texas. Laser measurements of shrub cover along flightlines were highly correlated (R 2 = 0.98) with ground measurements made with line-intercept methods. Stream channel cross sections on Goodwin Creek in Mississippi were measured quickly and accurately with airborne laser data. Airborne laser profile data were used to measure small gullies in a level fallow field and in field with mature soybeans. While conventional ground-based techniques can be used to make these measurements, airborne laser profiler techniques allow data to be collected quickly, at a high density, and in areas that are essentially inaccessible for ground surveys. Airborne laser profiler data can quantify landscape features related to erosion and runoff, and the laser proler has the potential to be a useful tool for providing other data for studying and managing natural resources

Design of Sail-Assisted Unmanned Surface Vehicle Intelligent Control System

Directory of Open Access Journals (Sweden)

Yong Ma

2016-01-01

Full Text Available To achieve the wind sail-assisted function of the unmanned surface vehicle (USV, this work focuses on the design problems of the sail-assisted USV intelligent control systems (SUICS and illustrates the implementation process of the SUICS. The SUICS consists of the communication system, the sensor system, the PC platform, and the lower machine platform. To make full use of the wind energy, in the SUICS, we propose the sail angle of attack automatic adjustment (Sail_4A algorithm and present the realization flow for each subsystem of the SUICS. By using the test boat, the design and implementation of the SUICS are fulfilled systematically. Experiments verify the performance and effectiveness of our SUICS. The SUICS enhances the intelligent utility of sustainable wind energy for the sail-assisted USV significantly and plays a vital role in shipping energy-saving emission reduction requirements issued by International Maritime Organization (IMO.

Featuring Multiple Local Optima to Assist the User in the Interpretation of Induced Bayesian Network Models

DEFF Research Database (Denmark)

Dalgaard, Jens; Pena, Jose; Kocka, Tomas

2004-01-01

We propose a method to assist the user in the interpretation of the best Bayesian network model indu- ced from data. The method consists in extracting relevant features from the model (e.g. edges, directed paths and Markov blankets) and, then, assessing the con¯dence in them by studying multiple...

Validation of in-line surface characterization by light scattering in Robot Assisted Polishing

DEFF Research Database (Denmark)

Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo

2014-01-01

The suitability of a commercial scattered light sensor for in-line characterization of fine surfaces in the roughness range Sa 1 – 30 nm generated by the Robot Assisted Polishing (RAP) was investigated and validated. A number of surfaces were generated and directly measured with the scattered light...

Thin plate spline feature point matching for organ surfaces in minimally invasive surgery imaging

Science.gov (United States)

Lin, Bingxiong; Sun, Yu; Qian, Xiaoning

2013-03-01

Robust feature point matching for images with large view angle changes in Minimally Invasive Surgery (MIS) is a challenging task due to low texture and specular reflections in these images. This paper presents a new approach that can improve feature matching performance by exploiting the inherent geometric property of the organ surfaces. Recently, intensity based template image tracking using a Thin Plate Spline (TPS) model has been extended for 3D surface tracking with stereo cameras. The intensity based tracking is also used here for 3D reconstruction of internal organ surfaces. To overcome the small displacement requirement of intensity based tracking, feature point correspondences are used for proper initialization of the nonlinear optimization in the intensity based method. Second, we generate simulated images from the reconstructed 3D surfaces under all potential view positions and orientations, and then extract feature points from these simulated images. The obtained feature points are then filtered and re-projected to the common reference image. The descriptors of the feature points under different view angles are stored to ensure that the proposed method can tolerate a large range of view angles. We evaluate the proposed method with silicon phantoms and in vivo images. The experimental results show that our method is much more robust with respect to the view angle changes than other state-of-the-art methods.

Comparing experts and novices in Martian surface feature change detection and identification

Science.gov (United States)

Wardlaw, Jessica; Sprinks, James; Houghton, Robert; Muller, Jan-Peter; Sidiropoulos, Panagiotis; Bamford, Steven; Marsh, Stuart

2018-02-01

Change detection in satellite images is a key concern of the Earth Observation field for environmental and climate change monitoring. Satellite images also provide important clues to both the past and present surface conditions of other planets, which cannot be validated on the ground. With the volume of satellite imagery continuing to grow, the inadequacy of computerised solutions to manage and process imagery to the required professional standard is of critical concern. Whilst studies find the crowd sourcing approach suitable for the counting of impact craters in single images, images of higher resolution contain a much wider range of features, and the performance of novices in identifying more complex features and detecting change, remains unknown. This paper presents a first step towards understanding whether novices can identify and annotate changes in different geomorphological features. A website was developed to enable visitors to flick between two images of the same location on Mars taken at different times and classify 1) if a surface feature changed and if so, 2) what feature had changed from a pre-defined list of six. Planetary scientists provided ;expert; data against which classifications made by novices could be compared when the project subsequently went public. Whilst no significant difference was found in images identified with surface changes by expert and novices, results exhibited differences in consensus within and between experts and novices when asked to classify the type of change. Experts demonstrated higher levels of agreement in classification of changes as dust devil tracks, slope streaks and impact craters than other features, whilst the consensus of novices was consistent across feature types; furthermore, the level of consensus amongst regardless of feature type. These trends are secondary to the low levels of consensus found, regardless of feature type or classifier expertise. These findings demand the attention of researchers who

Texture-based segmentation with Gabor filters, wavelet and pyramid decompositions for extracting individual surface features from areal surface topography maps

International Nuclear Information System (INIS)

Senin, Nicola; Leach, Richard K; Pini, Stefano; Blunt, Liam A

2015-01-01

Areal topography segmentation plays a fundamental role in those surface metrology applications concerned with the characterisation of individual topography features. Typical scenarios include the dimensional inspection and verification of micro-structured surface features, and the identification and characterisation of localised defects and other random singularities. While morphological segmentation into hills or dales is the only partitioning operation currently endorsed by the ISO specification standards on surface texture metrology, many other approaches are possible, in particular adapted from the literature on digital image segmentation. In this work an original segmentation approach is introduced and discussed, where topography partitioning is driven by information collected through the application of texture characterisation transforms popular in digital image processing. Gabor filters, wavelets and pyramid decompositions are investigated and applied to a selected set of test cases. The behaviour, performance and limitations of the proposed approach are discussed from the viewpoint of the identification and extraction of individual surface topography features. (paper)

Manufacture of functional surfaces through combined application of tool manufacturing processes and Robot Assisted Polishing

DEFF Research Database (Denmark)

Eriksen, Rasmus Solmer; Arentoft, Mogens; Grønbæk, J.

2012-01-01

The tool surface topography is often a key parameter in the tribological performance of modern metal forming tools. A new generation of multifunctional surfaces is achieved by combination of conventional tool manufacturing processes with a novel Robot Assisted Polishing process. This novel surface...

Remote sensing of coastal sea-surface features off northern British Columbia

International Nuclear Information System (INIS)

Jardine, I.D.; Thomson, K.A.; LeBlond, P.H.; Foreman, M.G.

1993-01-01

This article presents an overview of surface oceanographic features identified by AVHRR imagery in Hecate Strait and adjacent waters surrounding the Queen Charlotte Islands, Canada, an area still poor in in situ observations. The observed features and their temporal variability are interpreted in terms of meteorological and hydrological forcing. The effects of tidal mixing are discussed through the application of a finite element numerical model

Automatic selective feature retention in patient specific elastic surface registration

CSIR Research Space (South Africa)

Jansen van Rensburg, GJ

2011-01-01

Full Text Available The accuracy with which a recent elastic surface registration algorithm deforms the complex geometry of a skull is examined. This algorithm is then coupled to a line based algorithm as is frequently used in patient specific feature registration...

Multivariate Feature Selection of Image Descriptors Data for Breast Cancer with Computer-Assisted Diagnosis

Directory of Open Access Journals (Sweden)

Carlos E. Galván-Tejada

2017-02-01

Full Text Available Breast cancer is an important global health problem, and the most common type of cancer among women. Late diagnosis significantly decreases the survival rate of the patient; however, using mammography for early detection has been demonstrated to be a very important tool increasing the survival rate. The purpose of this paper is to obtain a multivariate model to classify benign and malignant tumor lesions using a computer-assisted diagnosis with a genetic algorithm in training and test datasets from mammography image features. A multivariate search was conducted to obtain predictive models with different approaches, in order to compare and validate results. The multivariate models were constructed using: Random Forest, Nearest centroid, and K-Nearest Neighbor (K-NN strategies as cost function in a genetic algorithm applied to the features in the BCDR public databases. Results suggest that the two texture descriptor features obtained in the multivariate model have a similar or better prediction capability to classify the data outcome compared with the multivariate model composed of all the features, according to their fitness value. This model can help to reduce the workload of radiologists and present a second opinion in the classification of tumor lesions.

Multivariate Feature Selection of Image Descriptors Data for Breast Cancer with Computer-Assisted Diagnosis.

Science.gov (United States)

Galván-Tejada, Carlos E; Zanella-Calzada, Laura A; Galván-Tejada, Jorge I; Celaya-Padilla, José M; Gamboa-Rosales, Hamurabi; Garza-Veloz, Idalia; Martinez-Fierro, Margarita L

2017-02-14

Breast cancer is an important global health problem, and the most common type of cancer among women. Late diagnosis significantly decreases the survival rate of the patient; however, using mammography for early detection has been demonstrated to be a very important tool increasing the survival rate. The purpose of this paper is to obtain a multivariate model to classify benign and malignant tumor lesions using a computer-assisted diagnosis with a genetic algorithm in training and test datasets from mammography image features. A multivariate search was conducted to obtain predictive models with different approaches, in order to compare and validate results. The multivariate models were constructed using: Random Forest, Nearest centroid, and K-Nearest Neighbor (K-NN) strategies as cost function in a genetic algorithm applied to the features in the BCDR public databases. Results suggest that the two texture descriptor features obtained in the multivariate model have a similar or better prediction capability to classify the data outcome compared with the multivariate model composed of all the features, according to their fitness value. This model can help to reduce the workload of radiologists and present a second opinion in the classification of tumor lesions.

Laser- and UV-assisted modification of polystyrene surfaces for control of protein adsorption and cell adhesion

International Nuclear Information System (INIS)

Pfleging, Wilhelm; Torge, Maika; Bruns, Michael; Trouillet, Vanessa; Welle, Alexander; Wilson, Sandra

2009-01-01

An appropriate choice of laser and process parameters enables new approaches for the fabrication of polymeric lab-on-chip devices with integrated functionalities. We will present our current research results in laser-assisted modification of polystyrene (PS) with respect to the fabrication of polymer devices for cell culture applications. For this purpose laser micro-patterning of PS and subsequent surface functionalization was investigated as function of laser and process parameters. A high power ArF-excimer laser radiation source with a pulse length of 19 ns as well as a high repetition ArF-excimer laser source with a pulse length of 5 ns were used in order to study the influence of laser pulse length on laser-induced surface oxidation. The change in surface chemistry was characterized by X-ray photoelectron spectroscopy and contact angle measurements. The difference between laser-assisted modification versus UV-lamp assisted modification was investigated. A photolytic activation of specific areas of the polymer surface and subsequent oxidization in oxygen or ambient air leads to a chemically modified polymer surface bearing carboxylic acid groups well-suited for controlled competitive protein adsorption or protein immobilization. Finally, distinct areas for cell growth and adhesion are obtained

Surface feature congruency effects in the object-reviewing paradigm are dependent on task memory demands.

Science.gov (United States)

Kimchi, Ruth; Pirkner, Yossef

2014-08-01

Perception of object continuity depends on establishing correspondence between objects viewed across disruptions in visual information. The role of spatiotemporal information in guiding object continuity is well documented; the role of surface features, however, is controversial. Some researchers have shown an object-specific preview benefit (OSPB)-a standard index of object continuity-only when correspondence could be based on an object's spatiotemporal information, whereas others have found color-based OSPB, suggesting that surface features can also guide object continuity. This study shows that surface feature-based OSPB is dependent on the task memory demands. When the task involved letters and matching just one target letter to the preview ones, no color congruency effect was found under spatiotemporal discontinuity and spatiotemporal ambiguity (Experiments 1-3), indicating that the absence of feature-based OSPB cannot be accounted for by salient spatiotemporal discontinuity. When the task involved complex shapes and matching two target shapes to the preview ones, color-based OSPB was obtained. Critically, however, when a visual working memory task was performed concurrently with the matching task, the presence of a nonspatial (but not a spatial) working memory load eliminated the color-based OSPB (Experiments 4 and 5). These results suggest that the surface feature congruency effects that are observed in the object-reviewing paradigm (with the matching task) reflect memory-based strategies that participants use to solve a memory-demanding task; therefore, they are not reliable measures of online object continuity and cannot be taken as evidence for the role of surface features in establishing object correspondence.

Acoustic emission-based in-process monitoring of surface generation in robot-assisted polishing

DEFF Research Database (Denmark)

Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo

2016-01-01

The applicability of acoustic emission (AE) measurements for in-process monitoring of surface generation in the robot-assisted polishing (RAP) was investigated. Surface roughness measurements require interruption of the process, proper surface cleaning and measurements that sometimes necessitate...... automatic detection of optimal process endpoint allow intelligent process control, creating fundamental elements in development of robust fully automated RAP process for its widespread industrial application....... removal of the part from the machine tool. In this study, stabilisation of surface roughness during polishing rotational symmetric surfaces by the RAP process was monitored by AE measurements. An AE sensor was placed on a polishing arm in direct contact with a bonded abrasive polishing tool...

Contributions of feature shapes and surface cues to the recognition of facial expressions.

Science.gov (United States)

Sormaz, Mladen; Young, Andrew W; Andrews, Timothy J

2016-10-01

Theoretical accounts of face processing often emphasise feature shapes as the primary visual cue to the recognition of facial expressions. However, changes in facial expression also affect the surface properties of the face. In this study, we investigated whether this surface information can also be used in the recognition of facial expression. First, participants identified facial expressions (fear, anger, disgust, sadness, happiness) from images that were manipulated such that they varied mainly in shape or mainly in surface properties. We found that the categorization of facial expression is possible in either type of image, but that different expressions are relatively dependent on surface or shape properties. Next, we investigated the relative contributions of shape and surface information to the categorization of facial expressions. This employed a complementary method that involved combining the surface properties of one expression with the shape properties from a different expression. Our results showed that the categorization of facial expressions in these hybrid images was equally dependent on the surface and shape properties of the image. Together, these findings provide a direct demonstration that both feature shape and surface information make significant contributions to the recognition of facial expressions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oriented coupling of major histocompatibility complex (MHC) to sensor surfaces using light assisted immobilisation technology

DEFF Research Database (Denmark)

Snabe, Torben; Røder, Gustav Andreas; Neves-Petersen, Maria Teresa

2005-01-01

Controlled and oriented immobilisation of proteins for biosensor purposes is of extreme interest since this provides more efficient sensors with a larger density of active binding sites per area compared to sensors produced by conventional immobilisation. In this paper oriented coupling of a major...... histocompatibility complex (MHC class I) to a sensor surface is presented. The coupling was performed using light assisted immobilisation--a novel immobilisation technology which allows specific opening of particular disulphide bridges in proteins which then is used for covalent bonding to thiol-derivatised surfaces...... via a new disulphide bond. Light assisted immobilisation specifically targets the disulphide bridge in the MHC-I molecule alpha(3)-domain which ensures oriented linking of the complex with the peptide binding site exposed away from the sensor surface. Structural analysis reveals that a similar...

Examining the Impact of Question Surface Features on Students' Answers to Constructed-Response Questions on Photosynthesis

Science.gov (United States)

Weston, Michele; Haudek, Kevin C.; Prevost, Luanna; Urban-Lurain, Mark; Merrill, John

2015-01-01

One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of…

Nanoscale silver-assisted wet etching of crystalline silicon for anti-reflection surface textures.

Science.gov (United States)

Li, Rui; Wang, Shuling; Chuwongin, Santhad; Zhou, Weidong

2013-01-01

We report here an electro-less metal-assisted chemical etching (MacEtch) process as light management surface-texturing technique for single crystalline Si photovoltaics. Random Silver nanostructures were formed on top of the Si surface based on the thin film evaporation and annealing process. Significant reflection reduction was obtained from the fabricated Si sample, with approximately 2% reflection over a wide spectra range (300 to 1050 nm). The work demonstrates the potential of MacEtch process for anti-reflection surface texture fabrication of large area, high efficiency, and low cost thin film solar cell.

Stereoscopic Feature Tracking System for Retrieving Velocity of Surface Waters

Science.gov (United States)

Zuniga Zamalloa, C. C.; Landry, B. J.

2017-12-01

The present work is concerned with the surface velocity retrieval of flows using a stereoscopic setup and finding the correspondence in the images via feature tracking (FT). The feature tracking provides a key benefit of substantially reducing the level of user input. In contrast to other commonly used methods (e.g., normalized cross-correlation), FT does not require the user to prescribe interrogation window sizes and removes the need for masking when specularities are present. The results of the current FT methodology are comparable to those obtained via Large Scale Particle Image Velocimetry while requiring little to no user input which allowed for rapid, automated processing of imagery.

Fusion of geometric and texture features for finger knuckle surface recognition

Directory of Open Access Journals (Sweden)

K. Usha

2016-03-01

Full Text Available Hand-based biometrics plays a significant role in establishing security for real-time environments involving human interaction and is found to be more successful in terms of high speed and accuracy. This paper investigates on an integrated approach for personal authentication using Finger Back Knuckle Surface (FBKS based on two methodologies viz., Angular Geometric Analysis based Feature Extraction Method (AGFEM and Contourlet Transform based Feature Extraction Method (CTFEM. Based on these methods, this personal authentication system simultaneously extracts shape oriented feature information and textural pattern information of FBKS for authenticating an individual. Furthermore, the proposed geometric and textural analysis methods extract feature information from both proximal phalanx and distal phalanx knuckle regions (FBKS, while the existing works of the literature concentrate only on the features of proximal phalanx knuckle region. The finger joint region found nearer to the tip of the finger is called distal phalanx region of FBKS, which is a unique feature and has greater potentiality toward identification. Extensive experiments conducted using newly created database with 5400 FBKS images and the obtained results infer that the integration of shape oriented features with texture feature information yields excellent accuracy rate of 99.12% with lowest equal error rate of 1.04%.

Analyzing surface features on icy satellites using a new two-layer analogue model

Science.gov (United States)

Morales, K. M.; Leonard, E. J.; Pappalardo, R. T.; Yin, A.

2017-12-01

The appearance of similar surface morphologies across many icy satellites suggests potentially unified formation mechanisms. Constraining the processes that shape the surfaces of these icy worlds is fundamental to understanding their rheology and thermal evolution—factors that have implications for potential habitability. Analogue models have proven useful for investigating and quantifying surface structure formation on Earth, but have only been sparsely applied to icy bodies. In this study, we employ an innovative two-layer analogue model that simulates a warm, ductile ice layer overlain by brittle surface ice on satellites such as Europa and Enceladus. The top, brittle layer is composed of fine-grained sand while the ductile, lower viscosity layer is made of putty. These materials were chosen because they scale up reasonably to the conditions on Europa and Enceladus. Using this analogue model, we investigate the role of the ductile layer in forming contractional structures (e.g. folds) that would compensate for the over-abundance of extensional features observed on icy satellites. We do this by simulating different compressional scenarios in the analogue model and analyzing whether the resulting features resemble those on icy bodies. If the resulting structures are similar, then the model can be used to quantify the deformation by calculating strain. These values can then be scaled up to Europa or Enceladus and used to quantity the observed surface morphologies and the amount of extensional strain accommodated by certain features. This presentation will focus on the resulting surface morphologies and the calculated strain values from several analogue experiments. The methods and findings from this work can then be expanded and used to study other icy bodies, such as Triton, Miranda, Ariel, and Pluto.

Orienting in virtual environments: How are surface features and environmental geometry weighted in an orientation task?

Science.gov (United States)

Kelly, Debbie M; Bischof, Walter F

2008-10-01

We investigated how human adults orient in enclosed virtual environments, when discrete landmark information is not available and participants have to rely on geometric and featural information on the environmental surfaces. In contrast to earlier studies, where, for women, the featural information from discrete landmarks overshadowed the encoding of the geometric information, Experiment 1 showed that when featural information is conjoined with the environmental surfaces, men and women encoded both types of information. Experiment 2 showed that, although both types of information are encoded, performance in locating a goal position is better if it is close to a geometrically or featurally distinct location. Furthermore, although features are relied upon more strongly than geometry, initial experience with an environment influences the relative weighting of featural and geometric cues. Taken together, these results show that human adults use a flexible strategy for encoding spatial information.

Preferential adsorption of gallium on GaAs(111)B surfaces during the initial growth of Au-assisted GaAs nanowires

International Nuclear Information System (INIS)

Shu Haibo; Chen Xiaoshuang; Ding Zongling; Dong Ruibin; Lu Wei

2010-01-01

The mechanism of the preferential adsorption of Ga on GaAs(111)B surfaces during the initial growth of Au-assisted GaAs nanowires is studied by using first-principles calculations within density functional theory. The calculated results show that Au preadsorption on GaAs(111)B surface significantly enhances the stability of the Ga adatom in comparison with the adsorption of Ga on clean GaAs(111)B surface. The stabilization of the Ga adatom is due to charge transfers from the Ga 4p and 4s states to the Au 6s and As 4p states. The number of Ga adatoms stabilized on GaAs(111)B surfaces depends on the size of surface Au cluster. The reason is that Au acted as an electron acceptor on GaAs(111)B surface assists the charge transfer of Ga adatoms for filling the partial unoccupied bands of GaAs(111)B surface. Our results are helpful to understand the growth of Au-assisted GaAs nanowires.

Associations between motor unit action potential parameters and surface EMG features.

Science.gov (United States)

Del Vecchio, Alessandro; Negro, Francesco; Felici, Francesco; Farina, Dario

2017-10-01

The surface interference EMG signal provides some information on the neural drive to muscles. However, the association between neural drive to muscle and muscle activation has long been debated with controversial indications due to the unavailability of motor unit population data. In this study, we clarify the potential and limitations of interference EMG analysis to infer motor unit recruitment strategies with an experimental investigation of several concurrently active motor units and of the associated features of the surface EMG. For this purpose, we recorded high-density surface EMG signals during linearly increasing force contractions of the tibialis anterior muscle, up to 70% of maximal force. The recruitment threshold (RT), conduction velocity (MUCV), median frequency (MDF MU ), and amplitude (RMS MU ) of action potentials of 587 motor units from 13 individuals were assessed and associated with features of the interference EMG. MUCV was positively associated with RT ( R 2 = 0.64 ± 0.14), whereas MDF MU and RMS MU showed a weaker relation with RT ( R 2 = 0.11 ± 0.11 and 0.39 ± 0.24, respectively). Moreover, the changes in average conduction velocity estimated from the interference EMG predicted well the changes in MUCV ( R 2 = 0.71), with a strong association to ankle dorsiflexion force ( R 2 = 0.81 ± 0.12). Conversely, both the average EMG MDF and RMS were poorly associated with motor unit recruitment. These results clarify the limitations of EMG spectral and amplitude analysis in inferring the neural strategies of muscle control and indicate that, conversely, the average conduction velocity could provide relevant information on these strategies. NEW & NOTEWORTHY The surface EMG provides information on the neural drive to muscles. However, the associations between EMG features and neural drive have been long debated due to unavailability of motor unit population data. Here, by using novel highly accurate decomposition of the EMG, we related motor unit

Effect of magnetic polarity on surface roughness during magnetic field assisted EDM of tool steel

Science.gov (United States)

Efendee, A. M.; Saifuldin, M.; Gebremariam, MA; Azhari, A.

2018-04-01

Electrical discharge machining (EDM) is one of the non-traditional machining techniques where the process offers wide range of parameters manipulation and machining applications. However, surface roughness, material removal rate, electrode wear and operation costs were among the topmost issue within this technique. Alteration of magnetic device around machining area offers exciting output to be investigated and the effects of magnetic polarity on EDM remain unacquainted. The aim of this research is to investigate the effect of magnetic polarity on surface roughness during magnetic field assisted electrical discharge machining (MFAEDM) on tool steel material (AISI 420 mod.) using graphite electrode. A Magnet with a force of 18 Tesla was applied to the EDM process at selected parameters. The sparks under magnetic field assisted EDM produced better surface finish than the normal conventional EDM process. At the presence of high magnetic field, the spark produced was squeezed and discharge craters generated on the machined surface was tiny and shallow. Correct magnetic polarity combination of MFAEDM process is highly useful to attain a high efficiency machining and improved quality of surface finish to meet the demand of modern industrial applications.

Feature Surfaces in Symmetric Tensor Fields Based on Eigenvalue Manifold.

Science.gov (United States)

Palacios, Jonathan; Yeh, Harry; Wang, Wenping; Zhang, Yue; Laramee, Robert S; Sharma, Ritesh; Schultz, Thomas; Zhang, Eugene

2016-03-01

Three-dimensional symmetric tensor fields have a wide range of applications in solid and fluid mechanics. Recent advances in the (topological) analysis of 3D symmetric tensor fields focus on degenerate tensors which form curves. In this paper, we introduce a number of feature surfaces, such as neutral surfaces and traceless surfaces, into tensor field analysis, based on the notion of eigenvalue manifold. Neutral surfaces are the boundary between linear tensors and planar tensors, and the traceless surfaces are the boundary between tensors of positive traces and those of negative traces. Degenerate curves, neutral surfaces, and traceless surfaces together form a partition of the eigenvalue manifold, which provides a more complete tensor field analysis than degenerate curves alone. We also extract and visualize the isosurfaces of tensor modes, tensor isotropy, and tensor magnitude, which we have found useful for domain applications in fluid and solid mechanics. Extracting neutral and traceless surfaces using the Marching Tetrahedra method can cause the loss of geometric and topological details, which can lead to false physical interpretation. To robustly extract neutral surfaces and traceless surfaces, we develop a polynomial description of them which enables us to borrow techniques from algebraic surface extraction, a topic well-researched by the computer-aided design (CAD) community as well as the algebraic geometry community. In addition, we adapt the surface extraction technique, called A-patches, to improve the speed of finding degenerate curves. Finally, we apply our analysis to data from solid and fluid mechanics as well as scalar field analysis.

Multimodal Discrimination of Schizophrenia Using Hybrid Weighted Feature Concatenation of Brain Functional Connectivity and Anatomical Features with an Extreme Learning Machine

Directory of Open Access Journals (Sweden)

Muhammad Naveed Iqbal Qureshi

2017-09-01

Full Text Available Multimodal features of structural and functional magnetic resonance imaging (MRI of the human brain can assist in the diagnosis of schizophrenia. We performed a classification study on age, sex, and handedness-matched subjects. The dataset we used is publicly available from the Center for Biomedical Research Excellence (COBRE and it consists of two groups: patients with schizophrenia and healthy controls. We performed an independent component analysis and calculated global averaged functional connectivity-based features from the resting-state functional MRI data for all the cortical and subcortical anatomical parcellation. Cortical thickness along with standard deviation, surface area, volume, curvature, white matter volume, and intensity measures from the cortical parcellation, as well as volume and intensity from sub-cortical parcellation and overall volume of cortex features were extracted from the structural MRI data. A novel hybrid weighted feature concatenation method was used to acquire maximal 99.29% (P < 0.0001 accuracy which preserves high discriminatory power through the weight of the individual feature type. The classification was performed by an extreme learning machine, and its efficiency was compared to linear and non-linear (radial basis function support vector machines, linear discriminant analysis, and random forest bagged tree ensemble algorithms. This article reports the predictive accuracy of both unimodal and multimodal features after 10-by-10-fold nested cross-validation. A permutation test followed the classification experiment to assess the statistical significance of the classification results. It was concluded that, from a clinical perspective, this feature concatenation approach may assist the clinicians in schizophrenia diagnosis.

Stream/Bounce Event Perception Reveals a Temporal Limit of Motion Correspondence Based on Surface Feature over Space and Time

Directory of Open Access Journals (Sweden)

Yousuke Kawachi

2011-06-01

Full Text Available We examined how stream/bounce event perception is affected by motion correspondence based on the surface features of moving objects passing behind an occlusion. In the stream/bounce display two identical objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other at coincidence. Here, surface features such as colour (Experiments 1 and 2 or luminance (Experiment 3 were switched between the two objects at coincidence. The moment of coincidence was invisible to observers due to an occluder. Additionally, the presentation of the moving objects was manipulated in duration after the feature switch at coincidence. The results revealed that a postcoincidence duration of approximately 200 ms was required for the visual system to stabilize judgments of stream/bounce events by determining motion correspondence between the objects across the occlusion on the basis of the surface feature. The critical duration was similar across motion speeds of objects and types of surface features. Moreover, controls (Experiments 4a–4c showed that cognitive bias based on feature (colour/luminance congruency across the occlusion could not fully account for the effects of surface features on the stream/bounce judgments. We discuss the roles of motion correspondence, visual feature processing, and attentive tracking in the stream/bounce judgments.

Characterisation and full-scale production testing of multifunctional surfaces for deep drawing applications

DEFF Research Database (Denmark)

Godi, Alessandro; Grønbæk, J.; De Chiffre, Leonardo

2017-01-01

assisted polishing. Advanced methods are employed to characterise the tools' surface topographies, detecting the surface features and analysing them separately according to their specific function. Four different multifunctional dies as well as two un-textured references are selected for testing. The tests......Full-scale deep drawing tests using tools featuring multifunctional surfaces are carried out in a production environment. Multifunctional tools display regularly spaced, transversal grooves for lubricant retention obtained by hard-turning, separated by smooth bearing plateaus realized by robot...

Correlation between the histological features of corneal surface pannus following ocular surface burns and the final outcome of cultivated limbal epithelial transplantation.

Science.gov (United States)

Sati, Alok; Basu, Sayan; Sangwan, Virender S; Vemuganti, Geeta K

2015-04-01

To report the influence of histological features of corneal surface pannus following ocular surface burn on the outcome of cultivated limbal epithelial transplantation (CLET). On retrospectively reviewing the medical records of the patients who underwent autologous CLET from April 2002 to June 2012 at L V Prasad Eye Institute, Hyderabad, India, we could trace the histological reports in only 90 records. These 90 records, besides clinical parameters, were reviewed for the influence of various histological features on the final outcome of CLET. The histological features include epithelial hyperplasia (21.1%), surface ulceration (2.2%), goblet cells (62.2%), squamous metaplasia (11.1%), active fibrosis (31.1%), severe inflammation (8.9%), multinucleated giant cells (3.3%), stromal calcification (8.9%) and active proliferating vessels (5.6%). Among these histological features, patients with either hyperplasia or calcification in their excised corneal pannus show an unfavourable outcome compared with patients without hyperplasia (p=0.003) or calcification (p=0.018). A similar unfavourable outcome was not seen with other histological features and various clinical parameters. Presence of either calcific deposits or hyperplasia in the excised corneal pannus provides poor prognostication; hence, a proper counselling of such patients is mandatory along with a close follow-up. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Characterization methods of nano-patterned surfaces generated by induction heating assisted injection molding

DEFF Research Database (Denmark)

Tang, Peter Torben; Ravn, Christian; Menotti, Stefano

2015-01-01

An induction heating-assisted injection molding (IHAIM) process developed by the authors is used to replicate surfaces containing random nano-patterns. The injection molding setup is developed so that an induction heating system rapidly heats the cavity wall at rates of up to 10◦C/s. In order...

Dependence of laser assisted cleaning of clad surfaces on the laser fluence

International Nuclear Information System (INIS)

Nilaya, J.P.; Raote, P.; Sai Prasad, M.B.; Biswas, D.J.; Aniruddha Kumar

2005-01-01

The decontamination factor is studied as a function of laser fluence for three kinds of clad surfaces viz., plain zircaloy, autoclaved zircaloy and SS with cesium as the test contamination. It has been found that the decontamination factor exhibits a maximal behaviour with the laser fluence and its maximum value occurs at different laser fluences in the three cases. The maximal behaviour is attributed to reduced coupling of energy from the laser beam to the substrate due to the initiation of surface-assisted optical breakdown. The results obtained in the experiment carried out in helium environment qualitatively support this explanation (author)

Reduced adhesion of macrophages on anodized titanium with select nanotube surface features

Directory of Open Access Journals (Sweden)

Balasubramanian K

2011-08-01

Full Text Available Amancherla Rajyalakshmi1, Batur Ercan2,3, K Balasubramanian1, Thomas J Webster2,31Non-Ferrous Materials Technology Development Centre, Hyderabad, India; 2School of Engineering, 3Department of Orthopedics, Brown University, Providence, RI, USAAbstract: One of the important prerequisites for a successful orthopedic implant apart from being osteoconductive is the elicitation of a favorable immune response that does not lead to the rejection of the implant by the host tissue. Anodization is one of the simplest surface modification processes used to create nanotextured and nanotubular features on metal oxides which has been shown to improve bone formation. Anodization of titanium (Ti leads to the formation of TiO2 nanotubes on the surface, and the presence of these nanotubes mimics the natural nanoscale features of bone, which in turn contributes to improved bone cell attachment, migration, and proliferation. However, inflammatory cell responses on anodized Ti remains to be tested. It is hypothesized that surface roughness and surface feature size on anodized Ti can be carefully manipulated to control immune cell (specifically, macrophages responses. Here, when Ti samples were anodized at 10 V in the presence of 1% hydrofluoric acid (HF for 1 minute, nanotextured (nonnanotube surfaces were created. When anodization of Ti samples was carried out with 1% HF for 10 minutes at 15 V, nanotubes with 40–50 nm diameters were formed, whereas at 20 V with 1% HF for 10 minutes, nanotubes with 60–70 nm diameters were formed. In this study, a reduced density of macrophages was observed after 24 hours of culture on nanotextured and nanotubular Ti samples which were anodized at 10, 15, and 20 V, compared with conventional unmodified Ti samples. This in vitro study thus demonstrated a reduced density of macrophages on anodized Ti, thereby providing further evidence of the greater efficacy of anodized Ti for orthopedic applications.Keywords: anodization, titanium

[INVITED] Laser gas assisted treatment of Ti-alloy: Analysis of surface characteristics

Science.gov (United States)

Yilbas, B. S.; Ali, H.; Karatas, C.

2016-04-01

Laser gas assisted treatment of Ti6Al4V alloy surface is carried out and nitrogen/oxygen mixture with partial pressure of PO2/PN2=1/3 is introduced during the surface treatment process. Analytical tools are used to characterize the laser treated surfaces. The fracture toughness at the surface and the residual stress in the surface region of the laser treated layer are measured. Scratch tests are carried out to determine the friction coefficient of the treated surface. It is found that closely spaced regular laser scanning tracks generates a self-annealing effect in the laser treated layer while lowering the stress levels in the treated region. Introducing high pressure gas mixture impingement at the surface results in formation of oxide and nitride species including, TiO, TiO2, TiN and TiOxNy in the surface region. A dense layer consisting of fine size grains are formed in the surface region of the laser treated layer, which enhances the microhardness at the surface. The fracture toughness reduces after the laser treatment process because of the microhardness enhancement at the surface. The residual stress formed is comprehensive, which is in the order of -350 MPa.

Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM phase images

Directory of Open Access Journals (Sweden)

M. O. Andreae

2008-10-01

Full Text Available We show that atomic force microscopy (AFM phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.

A statistical-textural-features based approach for classification of solid drugs using surface microscopic images.

Science.gov (United States)

Tahir, Fahima; Fahiem, Muhammad Abuzar

2014-01-01

The quality of pharmaceutical products plays an important role in pharmaceutical industry as well as in our lives. Usage of defective tablets can be harmful for patients. In this research we proposed a nondestructive method to identify defective and nondefective tablets using their surface morphology. Three different environmental factors temperature, humidity and moisture are analyzed to evaluate the performance of the proposed method. Multiple textural features are extracted from the surface of the defective and nondefective tablets. These textural features are gray level cooccurrence matrix, run length matrix, histogram, autoregressive model and HAAR wavelet. Total textural features extracted from images are 281. We performed an analysis on all those 281, top 15, and top 2 features. Top 15 features are extracted using three different feature reduction techniques: chi-square, gain ratio and relief-F. In this research we have used three different classifiers: support vector machine, K-nearest neighbors and naïve Bayes to calculate the accuracies against proposed method using two experiments, that is, leave-one-out cross-validation technique and train test models. We tested each classifier against all selected features and then performed the comparison of their results. The experimental work resulted in that in most of the cases SVM performed better than the other two classifiers.

Laser assisted decontamination of metal surface: Evidence of increased surface absorptivity due to field enhancement caused by transparent/semi-transparent contaminant particulates

International Nuclear Information System (INIS)

Nilaya, J. Padma; Biswas, Dhruba J.

2010-01-01

Small signal absorption measurements of the incident coherent radiation by the metal surface have revealed an increase in the absorption by the surface in presence of transparent/semi-transparent particulates on it. This effect, identified as field enhanced surface absorption, has been found to increase with reduction in the average particulate size. Consequently higher laser assisted removal efficiency of contamination from a metal surface has been observed for smaller contaminant particulates. These measurements have been carried out utilizing coherent radiations of two different wavelengths so chosen that for one the particulates are totally transparent while for the other they are partially transparent.

[Optimization of ultrasonic-assisted extraction of total flavonoids from leaves of the Artocarpus heterophyllus by response surface methodology].

Science.gov (United States)

Wang, Hong-wu; Liu, Yan-qing; Wang, Yuan-hong

2011-07-01

To investigate the ultrasonic-assisted extract on of total flavonoids from leaves of the Artocarpus heterophyllus. Investigated the effects of ethanol concentration, extraction time, and liquid-solid ratio on flavonoids yield. A 17-run response surface design involving three factors at three levels was generated by the Design-Expert software and experimental data obtained were subjected to quadratic regression analysis to create a mathematical model describing flavonoids extraction. The optimum ultrasonic assisted extraction conditions were: ethanol volume fraction 69.4% and liquid-solid ratio of 22.6:1 for 32 min. Under these optimized conditions, the yield of flavonoids was 7.55 mg/g. The Box-Behnken design and response surface analysis can well optimize the ultrasonic-assisted extraction of total flavonoids from Artocarpus heterophyllus.

Vacuum-assisted delivery

Science.gov (United States)

... medlineplus.gov/ency/patientinstructions/000514.htm Vacuum-assisted delivery To use the sharing features on this page, ... through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is fully dilated ( ...

Surface Features and Cathodoluminescence (CL) Characteristics of Corundum Gems from Eastern of Thailand

Science.gov (United States)

Boonsoong, A.

2017-12-01

Thailand has long been well known as a supplier of gemstones and also one of the world's color stone centers for decades. The principal gemstones are corundum, garnet and zircon. The corundum deposits of Chanthaburi-Trat Provinces form the most significant ruby-sapphire concentration in Thailand. Corundums are commonly found in secondary deposits (alluvium, elluvial, residual-soil and colluvium deposits as well as stream sediments) with the thickness of the gem-bearing layer varying from 10-100cm and the thickness of the overburden ranging up to 15m. A number of corundum samples were collected from each of the twenty-nine corundum deposits in the Chanthaburi-Trat gem fields, eastern of Thailand. Corundum varies in colour across the region with colours associated with three geographic zones; a western zone, characterized by blue, green and yellow sapphires; a middle zone with blue, green sapphires plus rubies; and an eastern zone yielding mainly rubies. This project has aim to study surface features and characterize the Cathodoluminescence (CL) of corundum gems in the Chanthaburi-Trat gem fields, Thailand. Surfaces of the corundums under a scanning electron microscope show triangular etch features and randomly oriented needle-like patterns. These reveal that the corundums have interacted with the magma during their ascent to the Earth's surface. Surface features attributable to transport and weathering processes are scratches, conchoidal fractures and a spongy surface appearance. Clay minerals and Fe-Ti oxide minerals deposited on the spongy surfaces of some corundums also indicate that these grains experienced chemical weathering or reacted with the soil solution while they were in the alluvium. Cathodoluminescence shows some blue sapphires to exhibit dull blue luminescence. The main cause of the CL appearance of sapphires is likely to be a quench centre, Fe2+ in their structure. The bright red luminescence in corundum reflects a high Cr3+ content and is always

Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

Energy Technology Data Exchange (ETDEWEB)

Hayat, Asma, E-mail: asmahayat@gcu.edu.pk; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

2015-12-01

Highlights: • Laser irradiation effects on Si surface have been explored. • An Excimer Laser was used as a source. • SEM analysis was performed to explore surface morphology. • Raman spectroscopy analysis was carried out to find crystallographical alterations. - Abstract: Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm{sup 2} and 4 J/cm{sup 2} resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm{sup 2} under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm{sup 2}, laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly

Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

International Nuclear Information System (INIS)

Hayat, Asma; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

2015-01-01

Highlights: • Laser irradiation effects on Si surface have been explored. • An Excimer Laser was used as a source. • SEM analysis was performed to explore surface morphology. • Raman spectroscopy analysis was carried out to find crystallographical alterations. - Abstract: Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm 2 and 4 J/cm 2 resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm 2 under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm 2 , laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly dependent upon the

Study on Effect of Ultrasonic Vibration on Grinding Force and Surface Quality in Ultrasonic Assisted Micro End Grinding of Silica Glass

Directory of Open Access Journals (Sweden)

Zhang Jianhua

2014-01-01

Full Text Available Ultrasonic vibration assisted micro end grinding (UAMEG is a promising processing method for micro parts made of hard and brittle materials. First, the influence of ultrasonic assistance on the mechanism of this processing technology is theoretically analyzed. Then, in order to reveal the effects of ultrasonic vibration and grinding parameters on grinding forces and surface quality, contrast grinding tests of silica glass with and without ultrasonic assistance using micro radial electroplated diamond wheel are conducted. The grinding forces are measured using a three-component dynamometer. The surface characteristics are detected using the scanning electron microscope. The experiment results demonstrate that grinding forces are significantly reduced by introducing ultrasonic vibration into conventional micro end grinding (CMEG of silica glass; ultrasonic assistance causes inhibiting effect on variation percentages of tangential grinding force with grinding parameters; ductile machining is easier to be achieved and surface quality is obviously improved due to ultrasonic assistance in UAMEG. Therefore, larger grinding depth and feed rate adopted in UAMEG can lead to the improvement of removal rate and machining efficiency compared with CMEG.

Applying tensor-based morphometry to parametric surfaces can improve MRI-based disease diagnosis.

Science.gov (United States)

Wang, Yalin; Yuan, Lei; Shi, Jie; Greve, Alexander; Ye, Jieping; Toga, Arthur W; Reiss, Allan L; Thompson, Paul M

2013-07-01

Many methods have been proposed for computer-assisted diagnostic classification. Full tensor information and machine learning with 3D maps derived from brain images may help detect subtle differences or classify subjects into different groups. Here we develop a new approach to apply tensor-based morphometry to parametric surface models for diagnostic classification. We use this approach to identify cortical surface features for use in diagnostic classifiers. First, with holomorphic 1-forms, we compute an efficient and accurate conformal mapping from a multiply connected mesh to the so-called slit domain. Next, the surface parameterization approach provides a natural way to register anatomical surfaces across subjects using a constrained harmonic map. To analyze anatomical differences, we then analyze the full Riemannian surface metric tensors, which retain multivariate information on local surface geometry. As the number of voxels in a 3D image is large, sparse learning is a promising method to select a subset of imaging features and to improve classification accuracy. Focusing on vertices with greatest effect sizes, we train a diagnostic classifier using the surface features selected by an L1-norm based sparse learning method. Stability selection is applied to validate the selected feature sets. We tested the algorithm on MRI-derived cortical surfaces from 42 subjects with genetically confirmed Williams syndrome and 40 age-matched controls, multivariate statistics on the local tensors gave greater effect sizes for detecting group differences relative to other TBM-based statistics including analysis of the Jacobian determinant and the largest eigenvalue of the surface metric. Our method also gave reasonable classification results relative to the Jacobian determinant, the pair of eigenvalues of the Jacobian matrix and volume features. This analysis pipeline may boost the power of morphometry studies, and may assist with image-based classification. Copyright © 2013

Biodegradation improvement of poly(3-hydroxy-butyrate) films by entomopathogenic fungi and UV-assisted surface functionalization.

Science.gov (United States)

Kessler, Felipe; Marconatto, Leticia; Rodrigues, Roberta da Silva Bussamara; Lando, Gabriela Albara; Schrank, Augusto; Vainstein, Marilene Henning; Weibel, Daniel Eduardo

2014-01-05

Ultraviolet (UV)-assisted surface modification in the presence of oxygen was used as initial step to achieve controlled degradation of poly(3-hydroxy-butyrate), PHB, films by entomopathogenic fungi. Treated surfaces were investigated by surface analysis techniques (water contact angle, Fourier Transformed Infrared Spectroscopy in Attenuated Total Reflectance mode, X-ray Photoelectron Spectroscopy, Near-edge X-ray Absorption Fine Structure, Gel Permeation Chromatography, Optical Microscopy, Scanning Electron Microscopy, and weight loss). After the UV-assisted treatments, new carbonyl groups in new chemical environments were detected by XPS and NEXAFS spectroscopy. The oxidizing atmosphere did not allow the formation of CC bonds, indicating that Norrish Type II mechanism is suppressed during or by the treatments. The higher hydrophilicity and concentration of oxygenated functional groups at the surface of the treated films possibly improved the biodegradation of the films. It was observed a clear increase in the growth of this fungus when oxygenated groups were grafted on the polymers surfaces. This simple methodology can be used to improve and control the degradation rate of PHB films in applications that require a controllable degradation rate. Copyright © 2013 Elsevier B.V. All rights reserved.

Laser-assisted modification of polystyrene surfaces for cell culture applications

International Nuclear Information System (INIS)

Pfleging, Wilhelm; Bruns, Michael; Welle, Alexander; Wilson, Sandra

2007-01-01

Laser-assisted patterning and modification of polystyrene (PS) was investigated with respect to applications in micro-fluidics and cell culture. For this purpose the wettability, the adsorption of proteins and the adhesion of animal cells were investigated as function of laser- and processing parameters. The change of surface chemistry was characterized by X-ray photoelectron spectroscopy. The local formation of chemical structures suitable for improved cell adhesion was realized on PS surfaces by UV laser irradiation. Above and below the laser ablation threshold two different mechanisms affecting cell adhesion were detected. In the first case the debris deposited on and along laser irradiated areas was responsible for improved cell adhesion, while in the second case a photolytic activation of the polymer surface including a subsequent oxidization in oxygen or ambient air is leading to a highly localized alteration of protein adsorption from cell culture media and finally to increased cell adhesion. Laser modifications of PS using suitable exposure doses and an appropriate choice of the processing gas (helium or oxygen) enabled a highly localized control of wetting. The dynamic advancing contact angle could be adjusted between 2 o and 150 o . The hydrophilic and hydrophobic behaviour are caused by chemical and topographical surface changes

Surface Modifications of Polymeric Materials for Application in Artificial Heart and Circulatory Assist Devices

NARCIS (Netherlands)

Feijen, J.; Engbers, G.H.M.; Terlingen, J.G.A.; van Delden, C.J.; Poot, A.A.; Vaudaux, P.; Akutsu, Tetsuzo; Koyanagi, Hitoshi

1996-01-01

Several methods have been developed to modify the surfaces of materials used in artificial hearts and circulatory assist devices to suppress the host response, especially with respect to the occurrence of clotting, cellular damage, and infections. In this review, special attention is paid to

Predicting the Occurrence of Cave-Inhabiting Fauna Based on Features of the Earth Surface Environment.

Science.gov (United States)

Christman, Mary C; Doctor, Daniel H; Niemiller, Matthew L; Weary, David J; Young, John A; Zigler, Kirk S; Culver, David C

2016-01-01

One of the most challenging fauna to study in situ is the obligate cave fauna because of the difficulty of sampling. Cave-limited species display patchy and restricted distributions, but it is often unclear whether the observed distribution is a sampling artifact or a true restriction in range. Further, the drivers of the distribution could be local environmental conditions, such as cave humidity, or they could be associated with surface features that are surrogates for cave conditions. If surface features can be used to predict the distribution of important cave taxa, then conservation management is more easily obtained. We examined the hypothesis that the presence of major faunal groups of cave obligate species could be predicted based on features of the earth surface. Georeferenced records of cave obligate amphipods, crayfish, fish, isopods, beetles, millipedes, pseudoscorpions, spiders, and springtails within the area of Appalachian Landscape Conservation Cooperative in the eastern United States (Illinois to Virginia and New York to Alabama) were assigned to 20 x 20 km grid cells. Habitat suitability for these faunal groups was modeled using logistic regression with twenty predictor variables within each grid cell, such as percent karst, soil features, temperature, precipitation, and elevation. Models successfully predicted the presence of a group greater than 65% of the time (mean = 88%) for the presence of single grid cell endemics, and for all faunal groups except pseudoscorpions. The most common predictor variables were latitude, percent karst, and the standard deviation of the Topographic Position Index (TPI), a measure of landscape rugosity within each grid cell. The overall success of these models points to a number of important connections between the surface and cave environments, and some of these, especially soil features and topographic variability, suggest new research directions. These models should prove to be useful tools in predicting the

Investigation of selected surface integrity features of duplex stainless steel (DSS after turning

Directory of Open Access Journals (Sweden)

G. Krolczyk

2015-01-01

Full Text Available The article presents surface roughness profiles and Abbott - Firestone curves with vertical and amplitude parameters of surface roughness after turning by means of a coated sintered carbide wedge with a coating with ceramic intermediate layer. The investigation comprised the influence of cutting speed on the selected features of surface integrity in dry machining. The material under investigation was duplex stainless steel with two-phase ferritic-austenitic structure. The tests have been performed under production conditions during machining of parts for electric motors and deep-well pumps. The obtained results allow to draw conclusions about the characteristics of surface properties of the machined parts.

Feature determination from powered wheelchair user joystick input characteristics for adapting driving assistance [version 3; referees: 2 approved

Directory of Open Access Journals (Sweden)

Michael Gillham

2018-05-01

Full Text Available Background: Many powered wheelchair users find their medical condition and their ability to drive the wheelchair will change over time. In order to maintain their independent mobility, the powered chair will require adjustment over time to suit the user's needs, thus regular input from healthcare professionals is required. These limited resources can result in the user having to wait weeks for appointments, resulting in the user losing independent mobility, consequently affecting their quality of life and that of their family and carers. In order to provide an adaptive assistive driving system, a range of features need to be identified which are suitable for initial system setup and can automatically provide data for re-calibration over the long term. Methods: A questionnaire was designed to collect information from powered wheelchair users with regard to their symptoms and how they changed over time. Another group of volunteer participants were asked to drive a test platform and complete a course which represented manoeuvring in a very confined space as quickly as possible. Two of those participants were also monitored over a longer period in their normal home daily environment. Features, thought to be suitable, were examined using pattern recognition classifiers to determine their suitability for identifying the changing user input over time. Results: The results are not designed to provide absolute insight into the individual user behaviour, as no ground truth of their ability has been determined, they do nevertheless demonstrate the utility of the measured features to provide evidence of the users’ changing ability over time whilst driving a powered wheelchair. Conclusions: Determining the driving features and adjustable elements provides the initial step towards developing an adaptable assistive technology for the user when the ground truths of the individual and their machine have been learned by a smart pattern recognition system.

Microwave assisted in situ synthesis of Ag–NaCMC films and their reproducible surface-enhanced Raman scattering signals

International Nuclear Information System (INIS)

Jiang, Tao; Li, Junpeng; Zhang, Li; Wang, Binbing; Zhou, Jun

2014-01-01

Graphical abstract: Two kinds of Ag–NaCMC films for surface-enhanced Raman scattering (SERS) were prepared by conventional heating and microwave assisted in situ reduction methods without any additional capping or reducing agents. A relatively narrow and symmetric surface plasmon resonance band was observed in the absorption spectra of the films fabricated by the microwave assisted in situ reduction method. More uniform silver nanoparticles (NPs) implied by the symmetric absorption spectrum were further confirmed by the scanning electron microscopy images. After the simulation of the E-field intensity distribution around the silver NPs in NaCMC film, the Raman scattering enhancement factors (EFs) of these films were then investigated with 4-mercaptobenzoic acid molecule as a SERS reporter. Improved reproducibility of SERS signal was obtained in the microwave assisted synthesized Ag–NaCMC film, although it maintained an EF as only 1.11 × 10 8 . The reproducible SERS signal of the Ag–NaCMC film is particularly attractive and this microwave assisted in situ reduction method is suitable for the production of excellent substrate for biosensor application. - Highlights: • The synthesis of Ag–NaCMC films was successfully fulfilled by a low-cost microwave method. • More uniform silver nanoparticles were observed in Ag–NaCMC film synthesized by microwave. • Improved reproducibility of SERS signal was obtained in microwave synthesized Ag–NaCMC film. - Abstract: Two kinds of Ag–NaCMC films for surface-enhanced Raman scattering (SERS) were prepared by conventional heating and microwave assisted in situ reduction methods without any additional capping or reducing agents. A relatively narrow and symmetric surface plasmon resonance band was observed in the absorption spectra of the films fabricated by the microwave assisted in situ reduction method. More uniform silver nanoparticles (NPs) implied by the symmetric absorption spectrum were further confirmed by

Technical assistance contractor Management Plan

International Nuclear Information System (INIS)

1993-09-01

The Technical Assistance Contractor (TAC) for the Uranium Mill Tailings Remedial Action (UMTRA) Project comprises Jacobs Engineering Group Inc. (JEG) and its major teaming partners [Roy F. Weston, Inc. (RFW), Sergent, Hauskins ampersand Beckwith Agra, Inc. (SHB Agra), and Geraghty ampersand Miller, Inc. (G ampersand M)]. The first three companies have worked together effectively on the UMTRA Project for more than 10 years. With the initiation of the UMTRA Groundwater Project in April 1991, a need arose to increase the TAC's groundwater technical breadth and depth, so G ampersand M was brought in to augment the team's capabilities. The TAC contract's scope is to provide technical, analytical, environmental, engineering, design, inspection, and management support services to the US Department of Energy (DOE) for both surface and groundwater projects. The TAC team continues to support the DOE in completing surface remedial actions and initiating groundwater remediation work for start-up, characterization, design, construction oversight, and remedial operations. A key feature of the TAC's management approach is the extensive set of communication systems implemented for the UMTRA Project. These systems assist all functional disciplines in performing UMTRA Project tasks associated with management, technical support, administrative support, and financial/project controls

Structural features of the adsorption layer of pentacene on the graphite surface and the PMMA/graphite hybrid surface

Science.gov (United States)

Fadeeva, A. I.; Gorbunov, V. A.; Litunenko, T. A.

2017-08-01

Using the molecular dynamics and the Monte Carlo methods, we have studied the structural features and growth mechanism of the pentacene film on graphite and polymethylmethacrylate /graphite surfaces. Monolayer capacity and molecular area, optimal angles between the pentacene molecules and graphite and PMMA/graphite surfaces as well as the characteristic angles between the neighboring pentacene molecules in the adsorption layer were estimated. It is shown that the orientation of the pentacene molecules in the film is determined by a number of factors, including the surface concentration of the molecules, relief of the surface, presence or absence of the polymer layer and its thickness. The pentacene molecules adsorbed on the graphite surface keep a horizontal position relative to the long axis at any surface coverage/thickness of the film. In the presence of the PMMA layer on the graphite, the increase of the number of pentacene molecules as well as the thickness of the PMMA layer induce the change of molecular orientation from predominantly horizontal to vertical one. The reason for such behavior is supposed to be the roughness of the PMMA surface.

Observation of surface features on an active landslide, and implications for understanding its history of movement

Directory of Open Access Journals (Sweden)

M. Parise

2003-01-01

Full Text Available Surface features are produced as a result of internal deformation of active landslides, and are continuously created and destroyed by the movement. Observation of their presence and distribution, and surveying of their evolution may provide insights for the zonation of the mass movement in sectors characterized by different behaviour. The present study analyses and describes some example of surface features observed on an active mass movement, the Slumgullion earthflow, in the San Juan Mountains of southwestern Colorado. The Slumgullion earthflow is one of the most famous and spectacular landslides in the world; it consists of a younger, active part which moves on and over an older, much larger, inactive part. Total length of the earthflow is 6.8 km, with an estimated volume of 170 × 10 6 m 3 . Its nearly constant rate of movement (ranging from about 2 m per year at the head, to a maximum of 6–7 m per year at its narrow and central part, to values between 1.3 and 2 m per year at the active toe, and the geological properties of moving material, are well suited for the observation of the development and evolution of surface features. In the last 11 years, repeated surveying at the Slumgullion site has been performed through recognition of surface features, measurements of their main characteristics, and detailed mapping. In this study, two sectors of the Slumgullion earthflow are analysed through comparison of the features observed in this time span, and evaluation of the changes occurred: they are the active toe and an area located at the left flank of the landslide. Choice of the sectors was dictated in the first case, by particular activity of movement and the nearby presence of elements at risk (highway located only 250 m downhill from the toe; and in the second case, by the presence of many surface features, mostly consisting of several generations of flank ridges. The active toe of the landslide is characterized by continuous movement

Cross-cutting Relationships of Surface Features on Europa

Science.gov (United States)

1997-01-01

This image of Jupiter's moon Europa shows a very complex terrain of ridges and fractures. The absence of large craters and the low number of small craters indicates that this surface is geologically young. The relative ages of the ridges can be determined by using the principle of cross-cutting relationships; i.e. older features are cross-cut by younger features. Using this principle, planetary geologists are able to unravel the sequence of events in this seemingly chaotic terrain to unfold Europa's unique geologic history.The spacecraft Galileo obtained this image on February 20, 1997. The area covered in this image is approximately 11 miles (18 kilometers) by 8.5 miles (14 kilometers) across, near 15 North, 273 West. North is toward the top of the image, with the sun illuminating from the right.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Study of Dynamic Features of Surface Plasma in High-Power Disk Laser Welding

International Nuclear Information System (INIS)

Wang Teng; Gao Xiangdong; Seiji, Katayama; Jin, Xiaoli

2012-01-01

High-speed photography was used to obtain the dynamic changes in the surface plasma during a high-power disk laser welding process. A color space clustering algorithm to extract the edge information of the surface plasma region was developed in order to improve the accuracy of image processing. With a comparative analysis of the plasma features, i.e., area and height, and the characteristics of the welded seam, the relationship between the surface plasma and the stability of the laser welding process was characterized, which provides a basic understanding for the real-time monitoring of laser welding.

Surface morphology of polyethylene glycol films produced by matrix-assisted pulsed laser evaporation (MAPLE): Dependence on substrate temperature

DEFF Research Database (Denmark)

Rodrigo, K.; Czuba, P.; Toftmann, B.

2006-01-01

The dependence of the surface morphology on the substrate temperature during film deposition was investigated for polyethylene glycol (PEG) films by matrix-assisted pulsed laser evaporation (MAPLE). The surface structure was studied with a combined technique of optical imaging and AFM measurements...

Laser gas assisted texturing and formation of nitride and oxynitride compounds on alumina surface: Surface response to environmental dust

Science.gov (United States)

Yilbas, B. S.; Ali, H.; Al-Sharafi, A.; Al-Aqeeli, N.

2018-03-01

Laser gas assisted texturing of alumina surface is carried out, and formation of nitride and oxynitride compounds in the surface vicinity is examined. The laser parameters are selected to create the surface topology consisting of micro/nano pillars with minimum defect sites including micro-cracks, voids and large size cavities. Morphological and hydrophobic characteristics of the textured surface are examined using the analytical tools. The characteristics of the environmental dust and its influence on the laser textured surface are studied while mimicking the local humid air ambient. Adhesion of the dry mud on the laser textured surface is assessed through the measurement of the tangential force, which is required to remove the dry mud from the surface. It is found that laser texturing gives rise to micro/nano pillars topology and the formation of AlN and AlON compounds in the surface vicinity. This, in turn, lowers the free energy of the textured surface and enhances the hydrophobicity of the surface. The liquid solution resulted from the dissolution of alkaline and alkaline earth metals of the dust particles in water condensate forms locally scattered liquid islands at the interface of mud and textured surface. The dried liquid solution at the interface increases the dry mud adhesion on the textured surface. Some dry mud residues remain on the textured surface after the dry mud is removed by a pressurized desalinated water jet.

Surface modification of chitin using ultrasound-assisted and supercritical CO{sub 2} technologies for cobalt adsorption

Energy Technology Data Exchange (ETDEWEB)

Dotto, Guilherme L., E-mail: guilherme_dotto@yahoo.com.br; Cunha, Jeanine M., E-mail: jeaninecunha@gmail.com; Calgaro, Camila O., E-mail: camila.itepjr@gmail.com; Tanabe, Eduardo H., E-mail: edutanabe@yahoo.com.br; Bertuol, Daniel A., E-mail: dbertuol@gmail.com

2015-09-15

Highlights: • Chitin was modified by ultrasound-assisted (UA) and supercritical (SCO{sub 2}) technologies. • Chitin, UA-chitin and SCO{sub 2}-chitin were used as adsorbents for Co(II). • UA and SCO{sub 2} treatments provided increase of 20 and 3 times in chitin surface area. • The Co(II) adsorption capacity increased until 67.8%, using UA-chitin. - Abstract: Ultrasound-assisted (UA) and supercritical CO{sub 2} technologies (SCO{sub 2}) were used to modify the chitin surface and, improve its adsorption characteristics regarding to cobalt. Chitin, before and after the treatments, was characterized by N{sub 2} adsorption isotherms (BET), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Unmodified and surface modified chitins were used as adsorbents to remove cobalt from aqueous solutions. The adsorption study was performed by equilibrium isotherms and kinetic curves. The chitin particle characteristics, such as, surface area, pore volume and porosity were improved by the UA and SCO{sub 2} treatments. The crystallinity index decreased after the UA and SCO{sub 2} treatments, and also, intense surface modifications were observed. Langmuir and Freundlich models were adequate to represent the adsorption equilibrium. The maximum adsorption capacities were 50.03, 83.94 and 63.08 mg g{sup −1} for unmodified chitin, UA surface modified chitin and SCO{sub 2} surface modified chitin. The adsorption kinetic curves were well represented by the pseudo-second order model. UA and SCO{sub 2} technologies are alternatives to modify the chitin surface and improve its adsorption characteristics.

Assisted delivery with forceps

Science.gov (United States)

... page: //medlineplus.gov/ency/patientinstructions/000509.htm Assisted delivery with forceps To use the sharing features on ... called vacuum assisted delivery . When is a Forceps Delivery Needed? Even after your cervix is fully dilated ( ...

Training Teaching Assistants.

Science.gov (United States)

Rava, Susan

1987-01-01

Washington University's (Missouri) Department of Romance Languages and Literature requires its graduate teaching assistants to take a one-semester pedagogy course to ensure their competence and effectiveness as teaching assistants. The course features seminars in which goals, expectations, and learning theories are discussed and practice teaching…

Surface chemistry of plasma-assisted atomic layer deposition of Al2O3 studied by infrared spectroscopy

NARCIS (Netherlands)

Langereis, E.; Keijmel, J.; Sanden, van de M.C.M.; Kessels, W.M.M.

2008-01-01

The surface groups created during plasma-assisted atomic layer deposition (ALD) of Al2O3 were studied by infrared spectroscopy. For temperatures in the range of 25–150 °C, –CH3 and –OH were unveiled as dominant surface groups after the Al(CH3)3precursor and O2 plasma half-cycles, respectively. At

Antiproliferative activity of Curcuma phaeocaulis Valeton extract using ultrasonic assistance and response surface methodology.

Science.gov (United States)

Wang, Xiaoqin; Jiang, Ying; Hu, Daode

2017-01-02

The objective of the study was to optimize the ultrasonic-assisted extraction of curdione, furanodienone, curcumol, and germacrone from Curcuma phaeocaulis Valeton (Val.) and investigate the antiproliferative activity of the extract. Under the suitable high-performance liquid chromatography condition, the calibration curves for these four tested compounds showed high levels of linearity and the recoveries of these four compounds were between 97.9 and 104.3%. Response surface methodology (RSM) combining central composite design and desirability function (DF) was used to define optimal extraction parameters. The results of RSM and DF revealed that the optimum conditions were obtained as 8 mL g -1 for liquid-solid ratio, 70% ethanol concentration, and 20 min of ultrasonic time. It was found that the surface structures of the sonicated herbal materials were fluffy and irregular. The C. phaeocaulis Val. extract significantly inhibited the proliferation of RKO and HT-29 cells in vitro. The results reveal that the RSM can be effectively used for optimizing the ultrasonic-assisted extraction of bioactive components from C. phaeocaulis Val. for antiproliferative activity.

Nano-coating of beta-galactosidase onto the surface of lactose by using an ultrasound-assisted technique

DEFF Research Database (Denmark)

Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki

2010-01-01

We nano-coated powdered lactose particles with the enzyme beta-galactosidase using an ultrasound-assisted technique. Atomization of the enzyme solution did not change its activity. The amount of surface-attached beta-galactosidase was measured through its enzymatic reaction product D-galactose us......We nano-coated powdered lactose particles with the enzyme beta-galactosidase using an ultrasound-assisted technique. Atomization of the enzyme solution did not change its activity. The amount of surface-attached beta-galactosidase was measured through its enzymatic reaction product D......-galactose using a standardized method. A near-linear increase was obtained in the thickness of the enzyme coat as the treatment proceeded. Interestingly, lactose, which is a substrate for beta-galactosidase, did not undergo enzymatic degradation during processing and remained unchanged for at least 1 month....... Stability of protein-coated lactose was due to the absence of water within the powder, as it was dry after the treatment procedure. In conclusion, we were able to attach the polypeptide to the core particles and determine precisely the coating efficiency of the surface-treated powder using a simple approach....

Shape based automated detection of pulmonary nodules with surface feature based false positive reduction

International Nuclear Information System (INIS)

Nomura, Y.; Itoh, H.; Masutani, Y.; Ohtomo, K.; Maeda, E.; Yoshikawa, T.; Hayashi, N.

2007-01-01

We proposed a shape based automated detection of pulmonary nodules with surface feature based false positive (FP) reduction. In the proposed system, the FP existing in internal of vessel bifurcation is removed using extracted surface of vessels and nodules. From the validation with 16 chest CT scans, we find that the proposed CAD system achieves 18.7 FPs/scan at 90% sensitivity, and 7.8 FPs/scan at 80% sensitivity. (orig.)

Memory for surface features of unfamiliar melodies: independent effects of changes in pitch and tempo.

Science.gov (United States)

Schellenberg, E Glenn; Stalinski, Stephanie M; Marks, Bradley M

2014-01-01

A melody's identity is determined by relations between consecutive tones in terms of pitch and duration, whereas surface features (i.e., pitch level or key, tempo, and timbre) are irrelevant. Although surface features of highly familiar recordings are encoded into memory, little is known about listeners' mental representations of melodies heard once or twice. It is also unknown whether musical pitch is represented additively or interactively with temporal information. In two experiments, listeners heard unfamiliar melodies twice in an initial exposure phase. In a subsequent test phase, they heard the same (old) melodies interspersed with new melodies. Some of the old melodies were shifted in key, tempo, or key and tempo. Listeners' task was to rate how well they recognized each melody from the exposure phase while ignoring changes in key and tempo. Recognition ratings were higher for old melodies that stayed the same compared to those that were shifted in key or tempo, and detrimental effects of key and tempo changes were additive in between-subjects (Experiment 1) and within-subjects (Experiment 2) designs. The results confirm that surface features are remembered for melodies heard only twice. They also imply that key and tempo are processed and stored independently.

Simulation study and guidelines to generate Laser-induced Surface Acoustic Waves for human skin feature detection

Science.gov (United States)

Li, Tingting; Fu, Xing; Chen, Kun; Dorantes-Gonzalez, Dante J.; Li, Yanning; Wu, Sen; Hu, Xiaotang

2015-12-01

Despite the seriously increasing number of people contracting skin cancer every year, limited attention has been given to the investigation of human skin tissues. To this regard, Laser-induced Surface Acoustic Wave (LSAW) technology, with its accurate, non-invasive and rapid testing characteristics, has recently shown promising results in biological and biomedical tissues. In order to improve the measurement accuracy and efficiency of detecting important features in highly opaque and soft surfaces such as human skin, this paper identifies the most important parameters of a pulse laser source, as well as provides practical guidelines to recommended proper ranges to generate Surface Acoustic Waves (SAWs) for characterization purposes. Considering that melanoma is a serious type of skin cancer, we conducted a finite element simulation-based research on the generation and propagation of surface waves in human skin containing a melanoma-like feature, determine best pulse laser parameter ranges of variation, simulation mesh size and time step, working bandwidth, and minimal size of detectable melanoma.

Land surface and climate parameters and malaria features in Vietnam

Science.gov (United States)

Liou, Y. A.; Anh, N. K.

2017-12-01

Land surface parameters may affect local microclimate, which in turn alters the development of mosquito habitats and transmission risks (soil-vegetation-atmosphere-vector borne diseases). Forest malaria is a chromic issue in Southeast Asian countries, in particular, such as Vietnam (in 1991, approximate 2 million cases and 4,646 deaths were reported (https://sites.path.org)). Vietnam has lowlands, sub-tropical high humidity, and dense forests, resulting in wide-scale distribution and high biting rate of mosquitos in Vietnam, becoming a challenging and out of control scenario, especially in Vietnamese Central Highland region. It is known that Vietnam's economy mainly relies on agriculture and malaria is commonly associated with poverty. There is a strong demand to investigate the relationship between land surface parameters (land cover, soil moisture, land surface temperature, etc.) and climatic variables (precipitation, humidity, evapotranspiration, etc.) in association with malaria distribution. GIS and remote sensing have been proven their powerful potentials in supporting environmental and health studies. The objective of this study aims to analyze physical attributes of land surface and climate parameters and their links with malaria features. The outcomes are expected to illustrate how remotely sensed data has been utilized in geohealth applications, surveillance, and health risk mapping. In addition, a platform with promising possibilities of allowing disease early-warning systems with citizen participation will be proposed.

Surface modification technique of structural ceramics: ion implantation-assisted multi-arc ion plating

International Nuclear Information System (INIS)

Peng Zhijian; Miao Hezhuo; Si Wenjie; Qi Longhao; Li Wenzhi

2003-01-01

Through reviewing the advantages and disadvantages of the existed surface modification techniques, a new technique, ion implantation-assisted multi-arc ion plating, was proposed. Using the proposed technique, the surfaces of silicon nitride ceramics were modified by Ti ion implantation, and then three kinds of ternary coatings, (Ti,Al)N, (Ti,Zr)N and (Ti,Cr)N, were deposited on the as-implanted ceramics. The coatings prepared by this technique are of high-hardness and well adhesive to the ceramic substrates. The maximal hardness measured by nanoindentation tests is more than 40 GPa. The maximal critical load by nanoscratch tests is more than 60 mN. The cutting tools prepared by this technique with the presented coatings are of excellent performance in industrial applications. The technique may be promising for the surface modification of structural ceramics. (orig.)

Electrical potential-assisted DNA hybridization. How to mitigate electrostatics for surface DNA hybridization.

Science.gov (United States)

Tymoczko, Jakub; Schuhmann, Wolfgang; Gebala, Magdalena

2014-12-24

Surface-confined DNA hybridization reactions are sensitive to the number and identity of DNA capture probes and experimental conditions such as the nature and the ionic strength of the electrolyte solution. When the surface probe density is high or the concentration of bulk ions is much lower than the concentration of ions within the DNA layer, hybridization is significantly slowed down or does not proceed at all. However, high-density DNA monolayers are attractive for designing high-sensitivity DNA sensors. Thus, circumventing sluggish DNA hybridization on such interfaces allows a high surface concentration of target DNA and improved signal/noise ratio. We present potential-assisted hybridization as a strategy in which an external voltage is applied to the ssDNA-modified interface during the hybridization process. Results show that a significant enhancement of hybridization can be achieved using this approach.

A New Sensor for Surface Process Quantification in the Geosciences - Image-Assisted Tacheometers

Science.gov (United States)

Vicovac, Tanja; Reiterer, Alexander; Rieke-Zapp, Dirk

2010-05-01

The quantification of earth surface processes in the geosciences requires precise measurement tools. Typical applications for precise measurement systems involve deformation monitoring for geo-risk management, detection of erosion rates, etc. Often employed for such applications are laser scanners, photogrammetric sensors and image-assisted tacheometers. Image-assisted tacheometers offer the user (metrology expert) an image capturing system (CCD/CMOS camera) in addition to 3D point measurements. The images of the telescope's visual field are projected onto the camera's chip. The camera is capable of capturing panoramic image mosaics through camera rotation if the axes of the measurement system are driven by computer controlled motors. With appropriate calibration, these images are accurately geo-referenced and oriented since the horizontal and vertical angles of rotation are continuously measured and fed into the computer. The oriented images can then directly be used for direction measurements with no need for control points in object space or further photogrammetric orientation processes. In such a system, viewing angles must be addressed to chip pixels inside the optical field of view. Hence dedicated calibration methods have to be applied, an autofocus unit has to be added to the optical path, and special digital image processing procedures have to be used to detect the points of interest on the objects to be measured. We present such a new optical measurement system for measuring and describing 3D surfaces for geosciences. Besides the technique and methods some practical examples will be shown. The system was developed at the Vienna University of Technology (Institute of Geodesy and Geophysics) - two interdisciplinary research project, i-MeaS and SedyMONT, have been launched with the purpose of measuring and interpreting 3D surfaces and surface processes. For the in situ measurement of bed rock erosion the level of surveying accuracy required for recurring sub

Masking considerations in chemically assisted ion beam etching of GaAs/AlGaAs laser structures

International Nuclear Information System (INIS)

Behfar-Rad, A.; Wong, S.S.; Davis, R.J.; Wolf, E.D.; Cornell Univ., Ithaca, NY

1989-01-01

The use of photoresist, Cr, and SiO 2 as etch masks for GaAs/AlGaAs structures in chemically assisted ion beam etching is reported. The optimized etch with a photoresist mask results in a high degree of anisotropy and smooth sidewalls. However, the etched surface contains undesirable features. The etch with a Cr mask is also highly anisotropic, and the etched surface is free of features. The drawback with Cr masks is that the sidewalls are rough. Vertical and smooth sidewalls as well as a featureless surface are obtained with a SiO 2 mask. The SiO 2 mask has been employed to etch the facets of monolithic GaAs/AlGaAs-based laser structures

HYDROLOGIC AND FEATURE-BASED SURFACE ANALYSIS FOR TOOL MARK INVESTIGATION ON ARCHAEOLOGICAL FINDS

Directory of Open Access Journals (Sweden)

K. Kovács

2012-07-01

Full Text Available The improvement of detailed surface documentation methods provides unique tool mark-study opportunities in the field of archaeological researches. One of these data collection techniques is short-range laser scanning, which creates a digital copy of the object’s morphological characteristics from high-resolution datasets. The aim of our work was the accurate documentation of a Bronze Age sluice box from Mitterberg, Austria with a spatial resolution of 0.2 mm. Furthermore, the investigation of the entirely preserved tool marks on the surface of this archaeological find was also accomplished by these datasets. The methodology of this tool mark-study can be summarized in the following way: At first, a local hydrologic analysis has been applied to separate the various patterns of tools on the finds’ surface. As a result, the XYZ coordinates of the special points, which represent the edge lines of the sliding tool marks, were calculated by buffer operations in a GIS environment. During the second part of the workflow, these edge points were utilized to manually clip the triangle meshes of these patterns in reverse engineering software. Finally, circle features were generated and analysed to determine the different sections along these sliding tool marks. In conclusion, the movement of the hand tool could be reproduced by the spatial analysis of the created features, since the horizontal and vertical position of the defined circle centre points indicated the various phases of the movements. This research shows an exact workflow to determine the fine morphological structures on the surface of the archaeological find.

The Impact of Solid Surface Features on Fluid-Fluid Interface Configuration

Science.gov (United States)

Araujo, J. B.; Brusseau, M. L. L.

2017-12-01

Pore-scale fluid processes in geological media are critical for a broad range of applications such as radioactive waste disposal, carbon sequestration, soil moisture distribution, subsurface pollution, land stability, and oil and gas recovery. The continued improvement of high-resolution image acquisition and processing have provided a means to test the usefulness of theoretical models developed to simulate pore-scale fluid processes, through the direct quantification of interfaces. High-resolution synchrotron X-ray microtomography is used in combination with advanced visualization tools to characterize fluid distributions in natural geologic media. The studies revealed the presence of fluid-fluid interface associated with macroscopic features on the surfaces of the solids such as pits and crevices. These features and respective fluid interfaces, which are not included in current theoretical or computational models, may have a significant impact on accurate simulation and understanding of multi-phase flow, energy, heat and mass transfer processes.

Far-Infrared Based Pedestrian Detection for Driver-Assistance Systems Based on Candidate Filters, Gradient-Based Feature and Multi-Frame Approval Matching.

Science.gov (United States)

Wang, Guohua; Liu, Qiong

2015-12-21

Far-infrared pedestrian detection approaches for advanced driver-assistance systems based on high-dimensional features fail to simultaneously achieve robust and real-time detection. We propose a robust and real-time pedestrian detection system characterized by novel candidate filters, novel pedestrian features and multi-frame approval matching in a coarse-to-fine fashion. Firstly, we design two filters based on the pedestrians' head and the road to select the candidates after applying a pedestrian segmentation algorithm to reduce false alarms. Secondly, we propose a novel feature encapsulating both the relationship of oriented gradient distribution and the code of oriented gradient to deal with the enormous variance in pedestrians' size and appearance. Thirdly, we introduce a multi-frame approval matching approach utilizing the spatiotemporal continuity of pedestrians to increase the detection rate. Large-scale experiments indicate that the system works in real time and the accuracy has improved about 9% compared with approaches based on high-dimensional features only.

Far-Infrared Based Pedestrian Detection for Driver-Assistance Systems Based on Candidate Filters, Gradient-Based Feature and Multi-Frame Approval Matching

Directory of Open Access Journals (Sweden)

Guohua Wang

2015-12-01

Full Text Available Far-infrared pedestrian detection approaches for advanced driver-assistance systems based on high-dimensional features fail to simultaneously achieve robust and real-time detection. We propose a robust and real-time pedestrian detection system characterized by novel candidate filters, novel pedestrian features and multi-frame approval matching in a coarse-to-fine fashion. Firstly, we design two filters based on the pedestrians’ head and the road to select the candidates after applying a pedestrian segmentation algorithm to reduce false alarms. Secondly, we propose a novel feature encapsulating both the relationship of oriented gradient distribution and the code of oriented gradient to deal with the enormous variance in pedestrians’ size and appearance. Thirdly, we introduce a multi-frame approval matching approach utilizing the spatiotemporal continuity of pedestrians to increase the detection rate. Large-scale experiments indicate that the system works in real time and the accuracy has improved about 9% compared with approaches based on high-dimensional features only.

Bio-inspired silicon nanospikes fabricated by metal-assisted chemical etching for antibacterial surfaces

Science.gov (United States)

Hu, Huan; Siu, Vince S.; Gifford, Stacey M.; Kim, Sungcheol; Lu, Minhua; Meyer, Pablo; Stolovitzky, Gustavo A.

2017-12-01

The recently discovered bactericidal properties of nanostructures on wings of insects such as cicadas and dragonflies have inspired the development of similar nanostructured surfaces for antibacterial applications. Since most antibacterial applications require nanostructures covering a considerable amount of area, a practical fabrication method needs to be cost-effective and scalable. However, most reported nanofabrication methods require either expensive equipment or a high temperature process, limiting cost efficiency and scalability. Here, we report a simple, fast, low-cost, and scalable antibacterial surface nanofabrication methodology. Our method is based on metal-assisted chemical etching that only requires etching a single crystal silicon substrate in a mixture of silver nitrate and hydrofluoric acid for several minutes. We experimentally studied the effects of etching time on the morphology of the silicon nanospikes and the bactericidal properties of the resulting surface. We discovered that 6 minutes of etching results in a surface containing silicon nanospikes with optimal geometry. The bactericidal properties of the silicon nanospikes were supported by bacterial plating results, fluorescence images, and scanning electron microscopy images.

Surface-assisted laser desorption ionization mass spectrometry techniques for application in forensics.

Science.gov (United States)

Guinan, Taryn; Kirkbride, Paul; Pigou, Paul E; Ronci, Maurizio; Kobus, Hilton; Voelcker, Nicolas H

2015-01-01

Matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) is an excellent analytical technique for the rapid and sensitive analysis of macromolecules (>700 Da), such as peptides, proteins, nucleic acids, and synthetic polymers. However, the detection of smaller organic molecules with masses below 700 Da using MALDI-MS is challenging due to the appearance of matrix adducts and matrix fragment peaks in the same spectral range. Recently, nanostructured substrates have been developed that facilitate matrix-free laser desorption ionization (LDI), contributing to an emerging analytical paradigm referred to as surface-assisted laser desorption ionization (SALDI) MS. Since SALDI enables the detection of small organic molecules, it is rapidly growing in popularity, including in the field of forensics. At the same time, SALDI also holds significant potential as a high throughput analytical tool in roadside, work place and athlete drug testing. In this review, we discuss recent advances in SALDI techniques such as desorption ionization on porous silicon (DIOS), nano-initiator mass spectrometry (NIMS) and nano assisted laser desorption ionization (NALDI™) and compare their strengths and weaknesses with particular focus on forensic applications. These include the detection of illicit drug molecules and their metabolites in biological matrices and small molecule detection from forensic samples including banknotes and fingerprints. Finally, the review highlights recent advances in mass spectrometry imaging (MSI) using SALDI techniques. © 2014 Wiley Periodicals, Inc.

Technical assistance contractor Management Plan. Final [report

Energy Technology Data Exchange (ETDEWEB)

1993-09-01

The Technical Assistance Contractor (TAC) for the Uranium Mill Tailings Remedial Action (UMTRA) Project comprises Jacobs Engineering Group Inc. (JEG) and its major teaming partners [Roy F. Weston, Inc. (RFW), Sergent, Hauskins & Beckwith Agra, Inc. (SHB Agra), and Geraghty & Miller, Inc. (G&M)]. The first three companies have worked together effectively on the UMTRA Project for more than 10 years. With the initiation of the UMTRA Groundwater Project in April 1991, a need arose to increase the TAC`s groundwater technical breadth and depth, so G&M was brought in to augment the team`s capabilities. The TAC contract`s scope is to provide technical, analytical, environmental, engineering, design, inspection, and management support services to the US Department of Energy (DOE) for both surface and groundwater projects. The TAC team continues to support the DOE in completing surface remedial actions and initiating groundwater remediation work for start-up, characterization, design, construction oversight, and remedial operations. A key feature of the TAC`s management approach is the extensive set of communication systems implemented for the UMTRA Project. These systems assist all functional disciplines in performing UMTRA Project tasks associated with management, technical support, administrative support, and financial/project controls.

Surface Phenomena During Plasma-Assisted Atomic Layer Etching of SiO2.

Science.gov (United States)

Gasvoda, Ryan J; van de Steeg, Alex W; Bhowmick, Ranadeep; Hudson, Eric A; Agarwal, Sumit

2017-09-13

Surface phenomena during atomic layer etching (ALE) of SiO 2 were studied during sequential half-cycles of plasma-assisted fluorocarbon (CF x ) film deposition and Ar plasma activation of the CF x film using in situ surface infrared spectroscopy and ellipsometry. Infrared spectra of the surface after the CF x deposition half-cycle from a C 4 F 8 /Ar plasma show that an atomically thin mixing layer is formed between the deposited CF x layer and the underlying SiO 2 film. Etching during the Ar plasma cycle is activated by Ar + bombardment of the CF x layer, which results in the simultaneous removal of surface CF x and the underlying SiO 2 film. The interfacial mixing layer in ALE is atomically thin due to the low ion energy during CF x deposition, which combined with an ultrathin CF x layer ensures an etch rate of a few monolayers per cycle. In situ ellipsometry shows that for a ∼4 Å thick CF x film, ∼3-4 Å of SiO 2 was etched per cycle. However, during the Ar plasma half-cycle, etching proceeds beyond complete removal of the surface CF x layer as F-containing radicals are slowly released into the plasma from the reactor walls. Buildup of CF x on reactor walls leads to a gradual increase in the etch per cycle.

Mapping stellar surface features

International Nuclear Information System (INIS)

Noah, P.V.

1987-01-01

New photometric and spectroscopic observations of the RS Canum Venaticorum binaries Sigma Geminorum and UX Arietis are reported along with details of the Doppler-imaging program SPOTPROF. The observations suggest that the starspot activity on Sigma Gem has decreased to 0.05 magnitude in two years. A photometric spot model for September 1984 to January 1985 found that a single spot covering 2% of the surface and 1000 K cooler than the surrounding photosphere could model the light variations. Equivalent-width observations contemporaneous with the photometric observations did not show any significant variations. Line-profile models from SPOTPROF predict that the variation of the equivalent width of the 6393 A Fe I line should be ∼ 1mA. Photometric observations of UX Ari from January 1984 to March 1985 show an 0.3 magnitude variation indicating a large spot group must cover the surface. Contemporaneous spectroscopic observations show asymmetric line profiles. The Doppler imaging and the photometric light-curve models were used in an iterative method to describe the stellar surface-spot distribution and successfully model both the photometric and the spectroscopic variations

Finding Objects for Assisting Blind People.

Science.gov (United States)

Yi, Chucai; Flores, Roberto W; Chincha, Ricardo; Tian, Yingli

2013-07-01

Computer vision technology has been widely used for blind assistance, such as navigation and wayfinding. However, few camera-based systems are developed for helping blind or visually-impaired people to find daily necessities. In this paper, we propose a prototype system of blind-assistant object finding by camera-based network and matching-based recognition. We collect a dataset of daily necessities and apply Speeded-Up Robust Features (SURF) and Scale Invariant Feature Transform (SIFT) feature descriptors to perform object recognition. Experimental results demonstrate the effectiveness of our prototype system.

LSAH: a fast and efficient local surface feature for point cloud registration

Science.gov (United States)

Lu, Rongrong; Zhu, Feng; Wu, Qingxiao; Kong, Yanzi

2018-04-01

Point cloud registration is a fundamental task in high level three dimensional applications. Noise, uneven point density and varying point cloud resolutions are the three main challenges for point cloud registration. In this paper, we design a robust and compact local surface descriptor called Local Surface Angles Histogram (LSAH) and propose an effectively coarse to fine algorithm for point cloud registration. The LSAH descriptor is formed by concatenating five normalized sub-histograms into one histogram. The five sub-histograms are created by accumulating a different type of angle from a local surface patch respectively. The experimental results show that our LSAH is more robust to uneven point density and point cloud resolutions than four state-of-the-art local descriptors in terms of feature matching. Moreover, we tested our LSAH based coarse to fine algorithm for point cloud registration. The experimental results demonstrate that our algorithm is robust and efficient as well.

Trichodesmium blooms and warm-core ocean surface features in the Arabian Sea and the Bay of Bengal.

Science.gov (United States)

Jyothibabu, R; Karnan, C; Jagadeesan, L; Arunpandi, N; Pandiarajan, R S; Muraleedharan, K R; Balachandran, K K

2017-08-15

Trichodesmium is a bloom-forming, diazotrophic, non-heterocystous cyanobacteria widely distributed in the warmer oceans, and their bloom is considered a 'biological indication' of stratification and nitrogen limitation in the ocean surface layer. In the first part of this paper, based on the retrospective analyses of the ocean surface mesoscale features associated with 59 Trichodesmium bloom incidences recorded in the past, 32 from the Arabian Sea and the Bay of Bengal, and 27 from the rest of the world, we have showed that warm-core features have an inducing effect on bloom formation. In the second part, we have considered the environmental preferences of Trichodesmium bloom based on laboratory and field studies across the globe, and proposed a view about how warm-core features could provide an inducing pre-requisite condition for the bloom formation in the Arabian Sea and the Bay of Bengal. Proposed that the subsurface waters of warm-core features maintain more likely chances for the conducive nutrient and light conditions required for the triggering of the blooms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gain-assisted superluminal propagation and rotary drag of photon and surface plasmon polaritons

Science.gov (United States)

Khan, Naveed; Amin Bacha, Bakht; Iqbal, Azmat; Ur Rahman, Amin; Afaq, A.

2017-07-01

Superluminal propagation of light is a well-established phenomenon and has motivated immense research interest that has led to state-of-the-art knowledge and potential applications in the emerging technology of quantum optics and photonics. This study presents a theoretical analysis of the gain-assisted superluminal light propagation in a four-level N -type atomic system by exploiting the scheme of electromagnetically induced gain and superluminal propagation of surface plasmon polaritons (SPPs) along the gain-assisted atomic-metal interface simultaneously. In addition, a theoretical demonstration is presented on the comparison between Fresnel's rotary photon drag and SPP drag in view of light polarization state rotation by rotating the coherent atomic medium and the atomic-metal interface, respectively. Analogous to photon drag in the superluminal anomalous dispersion region where light polarization rotation occurs opposite the rotation of the gain-assisted atomic medium, the rotation of the atomic-metal interface also rotates the polarization state of SPPs opposite the rotation of the interface. This further confirms the superluminal nature of SPPs propagating along the interface with negative group velocity. Rabi frequencies of the control and pump fields considerably modify both photon and SPP drag coefficients. Metal conductivity also controls SPP propagation.

Supplementary Microstructural Features Induced During Laser Surface Melting of Thermally Sprayed Inconel 625 Coatings

Science.gov (United States)

Ahmed, Nauman; Voisey, K. T.; McCartney, D. G.

2014-02-01

Laser surface melting of thermally sprayed coatings has the potential to enhance their corrosion properties by incorporating favorable microstructural changes. Besides homogenizing the as-sprayed structure, laser melting may induce certain microstructural modifications (i.e., supplementary features) in addition to those that directly improve the corrosion performance. Such features, being a direct result of the laser treatment process, are described in this paper which is part of a broader study in which high velocity oxy-fuel sprayed Inconel 625 coatings on mild-steel substrates were treated with a diode laser and the modified microstructure characterized using optical and scanning electron microscopy and x-ray diffraction. The laser treated coating features several different zones, including a region with a microstructure in which there is a continuous columnar dendritic structure through a network of retained oxide stringers.

Grating-assisted surface acoustic wave directional couplers

Science.gov (United States)

Golan, G.; Griffel, G.; Seidman, A.; Croitoru, N.

1991-07-01

Physical properties of novel grating-assisted Y directional couplers are examined using the coupled-mode theory. A general formalism for the analysis of the lateral perturbed directional coupler properties is presented. Explicit expressions for waveguide key parameters such as coupling length, grating period, and other structural characterizations, are obtained. The influence of other physical properties such as time and frequency response or cutoff conditions are also analyzed. A plane grating-assisted directional coupler is presented and examined as a basic component in the integrated acoustic technology.

Effect of Electropulsing-Assisted Ultrasonic Nanocrystalline Surface Modification on the Surface Mechanical Properties and Microstructure of Ti-6Al-4V Alloy

Science.gov (United States)

Ye, Yongda; Wang, Haibo; Tang, Guoyi; Song, Guolin

2018-05-01

The effect of electropulsing-assisted ultrasonic nanocrystalline surface modification (EP-UNSM) on surface mechanical properties and microstructure of Ti-6Al-4V alloy is investigated. Compared to conventional ultrasonic nanocrystalline surface modification (UNSM), EP-UNSM can effectively facilitate surface roughness and morphology, leading to excellent surface roughness (reduced from Ra 0.918 to Ra 0.028 μm by UNSM and Ra 0.019 μm by EP-UNSM) and smoother morphology with less cracks and defects. Surface friction coefficients are enhanced, resulting in lower and smoother friction coefficients. In addition, the surface-strengthened layer and ultra-refined grains are significantly enhanced with more severe plastic deformation and a greater surface hardness (a maximum hardness value of 407 HV and an effective depth of 550 μm, in comparison with the maximum hardness value of 364 HV and effective depth of 300 μm obtained by conventional UNSM). Remarkable enhancement of surface mechanical properties can be attributed to the refined gradient microstructure and the enhanced severe plastic deformation layer induced by coupling the effects of UNSM and electropulsing. The accelerated dislocation mobility and atom diffusion caused by the thermal and athermal effects of electropulsing treatment may be the primary intrinsic reasons for these improvements.

Surface features of central North America: a synoptic view from computer graphics

Science.gov (United States)

Pike, R.J.

1991-01-01

A digital shaded-relief image of the 48 contiguous United States shows the details of large- and small-scale landforms, including several linear trends. The features faithfully reflect tectonism, continental glaciation, fluvial activity, volcanism, and other surface-shaping events and processes. The new map not only depicts topography accurately and in its true complexity, but does so in one synoptic view that provides a regional context for geologic analysis unobscured by clouds, culture, vegetation, or artistic constraints. -Author

Identification of individual features in areal surface topography data by means of template matching and the ring projection transform

International Nuclear Information System (INIS)

Senin, Nicola; Moretti, Michele; Blunt, Liam A

2014-01-01

Starting from areal surface topography data as provided by current commercial three-dimensional (3D) profilometers and 3D digital microscopes, this work investigates the problem of automatically identifying and extracting functionally relevant, individual features within the acquisition area. Feature identification is achieved by adopting an original template-matching algorithmic procedure, based on applying the ring projection transform in combination with a parametric template. The proposed algorithmic procedure addresses in particular template-matching scenarios where significant variability may be associated with the features to be compared to the reference template. The algorithm is applied to a test case involving the characterization of the surface texture of a superabrasive polishing tool used in hard-disk manufacturing. (paper)

Electrochemically assisted deposition of strontium modified magnesium phosphate on titanium surfaces

International Nuclear Information System (INIS)

Meininger, M.; Wolf-Brandstetter, C.; Zerweck, J.; Wenninger, F.; Gbureck, U.; Groll, J.; Moseke, C.

2016-01-01

Electrochemically assisted deposition was utilized to produce ceramic coatings on the basis of magnesium ammonium phosphate (struvite) on corundum-blasted titanium surfaces. By the addition of defined concentrations of strontium nitrate to the coating electrolyte Sr 2+ ions were successfully incorporated into the struvite matrix. By variation of deposition parameters it was possible to fabricate coatings with different kinetics of Sr 2+ into physiological media, whereas the release of therapeutically relevant strontium doses could be sustained over several weeks. Morphological and crystallographic examinations of the immersed coatings revealed that the degradation of struvite and the release of Sr 2+ ions were accompanied by a transformation of the coating to a calcium phosphate based phase similar to low-crystalline hydroxyapatite. These findings showed that strontium doped struvite coatings may provide a promising degradable coating system for the local application of strontium or other biologically active metal ions in the implant–bone interface. - Highlights: • Sr-doped struvite coatings have been deposited on titanium by electrochemically assisted deposition. • Sr content can be adjusted by means of process time, current density and pulse mode. • Sr-doped coatings release therapeutically relevant Sr doses in physiological media for several weeks. • During immersion in physiological media Sr-doped struvite coatings transform into a low crystalline calcium phosphate phase.

Analysis of parameter and interaction between parameter of the microwave assisted transesterification process of coconut oil using response surface methodology

Science.gov (United States)

Hidayanti, Nur; Suryanto, A.; Qadariyah, L.; Prihatini, P.; Mahfud, Mahfud

2015-12-01

A simple batch process was designed for the transesterification of coconut oil to alkyl esters using microwave assisted method. The product with yield above 93.225% of alkyl ester is called the biodiesel fuel. Response surface methodology was used to design the experiment and obtain the maximum possible yield of biodiesel in the microwave-assisted reaction from coconut oil with KOH as the catalyst. The results showed that the time reaction and concentration of KOH catalyst have significant effects on yield of alkyl ester. Based on the response surface methodology using the selected operating conditions, the time of reaction and concentration of KOH catalyst in transesterification process were 150 second and 0.25%w/w, respectively. The largest predicted and experimental yield of alkyl esters (biodiesel) under the optimal conditions are 101.385% and 93.225%, respectively. Our findings confirmed the successful development of process for the transesterification reaction of coconut oil by microwave-assisted heating, which is effective and time-saving for alkyl ester production.

Finding Objects for Assisting Blind People

OpenAIRE

Yi, Chucai; Flores, Roberto W.; Chincha, Ricardo; Tian, YingLi

2013-01-01

Computer vision technology has been widely used for blind assistance, such as navigation and wayfinding. However, few camera-based systems are developed for helping blind or visually-impaired people to find daily necessities. In this paper, we propose a prototype system of blind-assistant object finding by camera-based network and matching-based recognition. We collect a dataset of daily necessities and apply Speeded-Up Robust Features (SURF) and Scale Invariant Feature Transform (SIFT) featu...

Measurements of land surface features using an airborne laser altimeter: the HAPEX-Sahel experiment

International Nuclear Information System (INIS)

Ritchie, J.C.; Menenti, M.; Weltz, M.A.

1997-01-01

An airborne laser profiling altimeter was used to measure surface features and properties of the landscape during the HAPEX-Sahel Experiment in Niger, Africa in September 1992. The laser altimeter makes 4000 measurements per second with a vertical resolution of 5 cm. Airborne laser and detailed field measurements of vegetation heights had similar average heights and frequency distribution. Laser transects were used to estimate land surface topography, gully and channel morphology, and vegetation properties ( height, cover and distribution). Land surface changes related to soil erosion and channel development were measured. For 1 km laser transects over tiger bush communities, the maximum vegetation height was between 4-5 and 6-5 m, with an average height of 21 m. Distances between the centre of rows of tiger bush vegetation averaged 100 m. For two laser transects, ground cover for tiger bush was estimated to be 225 and 301 per cent for vegetation greater than 0-5m tall and 190 and 25-8 per cent for vegetation greater than 10m tall. These values are similar to published values for tiger bush. Vegetation cover for 14 and 18 km transects was estimated to be 4 per cent for vegetation greater than 0-5 m tall. These cover values agree within 1-2 per cent with published data for short transects (⩾ 100 m) for the area. The laser altimeter provided quick and accurate measurements for evaluating changes in land surface features. Such information provides a basis for understanding land degradation and a basis for management plans to rehabilitate the landscape. (author)

MHD Flow Towards a Permeable Surface with Prescribed Wall Heat Flux

International Nuclear Information System (INIS)

Ishak, Anuar; Nazar, Roslinda; Pop, Ioan

2009-01-01

The steady magnetohydrodynamic (MHD) mixed convection flow towards a vertical permeable surface with prescribed heat flux is investigated. The governing partial differential equations are transformed into a system of ordinary differential equations, which is then solved numerically by a finite-difference method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analysed and discussed. Both assisting and opposing flows are considered. It is found that dual solutions exist for the assisting flow, besides the solutions usually reported in the literature for the opposing fow

Thermal Infrared Spectra of Microcrystalline Sedimentary Phases: Effects of Natural Surface Roughness on Spectral Feature Shape

Science.gov (United States)

Hardgrove, C.; Rogers, A. D.

2012-03-01

Thermal infrared spectral features of common microcrystalline phases (chert, alabaster, micrite) are presented. Spectra are sensitive to mineralogy and micron-scale (~1-25 µm) surface roughness. Roughness is on the scale of the average crystal size.

Behind every innovative solution lies an obscure feature

Directory of Open Access Journals (Sweden)

Lee Spector (Fellow ISGEC

2012-06-01

Full Text Available The Obscure Features Hypothesis (OFH for innovation states that a two-step process undergirds almost all innovative solutions: (1 notice an infrequently observed or new (i.e., obscure feature of the problem and (2 construct an interaction involving the obscure feature that produces the desired effects to solve the problem. The OFH leads to a systematic derivation of innovation-enhancing techniques by engaging in two tasks. First, we developed a 32-category system of the types of features possessable by a physical object or material. This Feature Type Taxonomy (FTT provides a panoramic view of the space of features and assists in searches for the obscure ones. Second, we are articulating the many cognitive reasons that obscure features are overlooked and are developing countering techniques for each known reason. We present the implications and techniques of the OFH, as well as indicate how software can assist innovators in the effective use of these innovation-enhancing techniques.

AssistMe robot, an assistance robotic platform

Directory of Open Access Journals (Sweden)

A. I. Alexan

2012-06-01

Full Text Available This paper presents the design and implementation of a full size assistance robot. Its main purpose it to assist a person and eventually avoid a life threatening situation. Its implementation revolves around a chipKIT Arduino board that interconnects a robotic base controller with a 7 inch TABLET PC and various sensors. Due to the Android and Arduino combination, the robot can interact with the person and provide an easy development platform for future improvement and feature adding. The TABLET PC is Webcam, WIFI and Bluetooth enabled, offering a versatile platform that is able to process data and in the same time provide the user a friendly interface.

Electrochemically assisted deposition of strontium modified magnesium phosphate on titanium surfaces

Energy Technology Data Exchange (ETDEWEB)

Meininger, M. [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg (Germany); Wolf-Brandstetter, C. [Max Bergmann Center for Biomaterials, Technical University of Dresden, Budapester Straße 27, D-01069 Dresden (Germany); Zerweck, J.; Wenninger, F.; Gbureck, U.; Groll, J. [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg (Germany); Moseke, C., E-mail: claus.moseke@fmz.uni-wuerzburg.de [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg (Germany)

2016-10-01

Electrochemically assisted deposition was utilized to produce ceramic coatings on the basis of magnesium ammonium phosphate (struvite) on corundum-blasted titanium surfaces. By the addition of defined concentrations of strontium nitrate to the coating electrolyte Sr{sup 2+} ions were successfully incorporated into the struvite matrix. By variation of deposition parameters it was possible to fabricate coatings with different kinetics of Sr{sup 2+} into physiological media, whereas the release of therapeutically relevant strontium doses could be sustained over several weeks. Morphological and crystallographic examinations of the immersed coatings revealed that the degradation of struvite and the release of Sr{sup 2+} ions were accompanied by a transformation of the coating to a calcium phosphate based phase similar to low-crystalline hydroxyapatite. These findings showed that strontium doped struvite coatings may provide a promising degradable coating system for the local application of strontium or other biologically active metal ions in the implant–bone interface. - Highlights: • Sr-doped struvite coatings have been deposited on titanium by electrochemically assisted deposition. • Sr content can be adjusted by means of process time, current density and pulse mode. • Sr-doped coatings release therapeutically relevant Sr doses in physiological media for several weeks. • During immersion in physiological media Sr-doped struvite coatings transform into a low crystalline calcium phosphate phase.

Surface plasmon resonance assisted rapid laser joining of glass

Energy Technology Data Exchange (ETDEWEB)

Zolotovskaya, Svetlana A.; Tang, Guang; Abdolvand, Amin, E-mail: a.abdolvand@dundee.ac.uk [School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); Wang, Zengbo [School of Electronic Engineering, Bangor University, Bangor LL57 1UT (United Kingdom)

2014-08-25

Rapid and strong joining of clear glass to glass containing randomly distributed embedded spherical silver nanoparticles upon nanosecond pulsed laser irradiation (∼40 ns and repetition rate of 100 kHz) at 532 nm is demonstrated. The embedded silver nanoparticles were ∼30–40 nm in diameter, contained in a thin surface layer of ∼10 μm. A joint strength of 12.5 MPa was achieved for a laser fluence of only ∼0.13 J/cm{sup 2} and scanning speed of 10 mm/s. The bonding mechanism is discussed in terms of absorption of the laser energy by nanoparticles and the transfer of the accumulated localised heat to the surrounding glass leading to the local melting and formation of a strong bond. The presented technique is scalable and overcomes a number of serious challenges for a widespread adoption of laser-assisted rapid joining of glass substrates, enabling applications in the manufacture of microelectronic devices, sensors, micro-fluidic, and medical devices.

Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM) phase images

OpenAIRE

G. Helas; M. O. Andreae

2008-01-01

We show that atomic force microscopy (AFM) phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly...

Terrestrial Analogs for Surface Properties Associated with Impact Cratering on the Moon - Self-secondary Impact Features at Kings Bowl, Idaho

Science.gov (United States)

Matiella Novak, M. A.; Zanetti, M.; Neish, C.; Kukko, A.; Fan, K.; Heldmann, J.; Hughes, S. S.

2017-12-01

The Kings Bowl (KB) eruptive fissure and lava field, located in the southern end of Craters of the Moon National Monument, Idaho, is an ideal location for planetary analogue field studies of surface properties related to volcanic and impact processes. Here we look at possible impact features present in the KB lava field near the main vent that resulted in squeeze-ups of molten lava from beneath a semi-solid lava lake crust. These may have been caused by the ejection of blocks during the phreatic eruption that formed the Kings Bowl pit, and their subsequent impact into a partially solidified lava pond. We compare and contrast these features with analogous self-secondary impact features, such as irregular, rimless secondary craters ("splash craters") observed in lunar impact melt deposits, to better understand how self-secondary impacts determine the surface properties of volcanic and impact crater terrains. We do this by analyzing field measurements of these features, as well as high-resolution DEM data collected through the Kinematic LiDAR System (KLS), both of which give us feature dimensions and distributions. We then compare these data with self-secondary impact features on the Moon and related surface roughness constrained through Lunar Reconnaissance Orbiter observations (Mini-RF and LROC NACs). Possible self-secondary impact features can be found in association with many lunar impact craters. These are formed when ballistic ejecta from the crater falls onto the ejecta blanket and melt surrounding the newly formed crater. Self-secondary impact features involving impact melt deposits are particularly useful to study because the visibly smooth melt texture serves to highlight the impact points in spacecraft imagery. The unusual morphology of some of these features imply that they formed when the melt had not yet completely solidified, strongly suggesting a source of impactors from the primary crater itself. We will also discuss ongoing efforts to integrate field

Feature-based tolerancing for intelligent inspection process definition

International Nuclear Information System (INIS)

Brown, C.W.

1993-07-01

This paper describes a feature-based tolerancing capability that complements a geometric solid model with an explicit representation of conventional and geometric tolerances. This capability is focused on supporting an intelligent inspection process definition system. The feature-based tolerance model's benefits include advancing complete product definition initiatives (e.g., STEP -- Standard for Exchange of Product model dam), suppling computer-integrated manufacturing applications (e.g., generative process planning and automated part programming) with product definition information, and assisting in the solution of measurement performance issues. A feature-based tolerance information model was developed based upon the notion of a feature's toleranceable aspects and describes an object-oriented scheme for representing and relating tolerance features, tolerances, and datum reference frames. For easy incorporation, the tolerance feature entities are interconnected with STEP solid model entities. This schema will explicitly represent the tolerance specification for mechanical products, support advanced dimensional measurement applications, and assist in tolerance-related methods divergence issues

Ultrasound-assisted extraction of Mangiferin from Mango (Mangifera indica L.) leaves using response surface methodology.

Science.gov (United States)

Zou, Tang-Bin; Xia, En-Qin; He, Tai-Ping; Huang, Ming-Yuan; Jia, Qing; Li, Hua-Wen

2014-01-27

Mangiferin is a xanthone widely distributed in higher plants showing antioxidative, antiviral, anticancer, antidiabetic, immunomodulatory, hepatoprotective and analgesic effects. In the present study, an ultrasonic-assisted extraction method was developed for the effective extraction of mangiferin from mango leaves. Some parameters such as ethanol concentration, liquid-to-solid ratio, extraction temperature, and extraction time were optimized by single-factor experiment and response surface methodology. The optimal extraction conditions were 44% ethanol, the liquid-to-solid ratio was 38:1, and extraction for 19.2 min at 60 °C under ultrasound irradiation of 200 W. Under optimal conditions, the yield of mangiferin was 58.46 ± 1.27 mg/g. The results obtained are helpful for the full utilization of mango leaves, and also indicated that ultrasonic-assisted extraction is a very useful method for the extraction of mangiferin from plant materials.

Use of the discriminant Fourier-derived cepstrum with feature-level post-processing for surface electromyographic signal classification

International Nuclear Information System (INIS)

Chen, Xinpu; Zhu, Xiangyang; Zhang, Dingguo

2009-01-01

Myoelectrical pattern classification is a crucial part in multi-functional prosthesis control. This paper investigates a discriminant Fourier-derived cepstrum (DFC) and feature-level post-processing (FLPP) to discriminate hand and wrist motions using the surface electromyographic signal. The Fourier-derived cepstrum takes advantage of the Fourier magnitude or sub-band power energy of signals directly and provides flexible use of spectral information changing with different motions. Appropriate cepstral coefficients are selected by a proposed separability criterion to construct DFC features. For the post-processing, FLPP which combines features from several analysis windows is used to improve the feature performance further. In this work, two classifiers (a linear discriminant classifier and quadratic discriminant classifier) without hyper-parameter optimization are employed to simplify the training procedure and avoid the possible bias of feature evaluation. Experimental results of the 11-motion problem show that the proposed DFC feature outperforms traditional features such as time-domain statistics and autoregressive-derived cepstrum in terms of the classification accuracy, and it is a promising method for the multi-functionality and high-accuracy control of myoelectric prostheses

Study of the deposition features of the organic dye Rhodamine B on the porous surface of silicon with different pore sizes

Energy Technology Data Exchange (ETDEWEB)

Lenshin, A. S., E-mail: lenshinas@phys.vsu.ru; Seredin, P. V.; Kavetskaya, I. V.; Minakov, D. A.; Kashkarov, V. M. [Voronezh State University (Russian Federation)

2017-02-15

The deposition features of the organic dye Rhodamine B on the porous surface of silicon with average pore sizes of 50–100 and 100–250 nm are studied. Features of the composition and optical properties of the obtained systems are studied using infrared and photoluminescence spectroscopy. It is found that Rhodamine-B adsorption on the surface of por-Si with various porosities is preferentially physical. The optimal technological parameters of its deposition are determined.

Small-Scale Morphological Features on a Solid Surface Processed by High-Pressure Abrasive Water Jet

Directory of Open Access Journals (Sweden)

Can Kang

2013-08-01

Full Text Available Being subjected to a high-pressure abrasive water jet, solid samples will experience an essential variation of both internal stress and physical characteristics, which is closely associated with the kinetic energy attached to the abrasive particles involved in the jet stream. Here, experiments were performed, with particular emphasis being placed on the kinetic energy attenuation and turbulent features in the jet stream. At jet pressure of 260 MPa, mean velocity and root-mean-square (RMS velocity on two jet-stream sections were acquired by utilizing the phase Doppler anemometry (PDA technique. A jet-cutting experiment was then carried out with Al-Mg alloy samples being cut by an abrasive water jet. Morphological features and roughness on the cut surface were quantitatively examined through scanning electron microscopy (SEM and optical profiling techniques. The results indicate that the high-pressure water jet is characterized by remarkably high mean flow velocities and distinct velocity fluctuations. Those irregular pits and grooves on the cut surfaces indicate both the energy attenuation and the development of radial velocity components in the jet stream. When the sample is positioned with different distances from the nozzle outlet, the obtained quantitative surface roughness varies accordingly. A descriptive model highlighting the behaviors of abrasive particles in jet-cutting process is established in light of the experimental results and correlation analysis.

Small-Scale Morphological Features on a Solid Surface Processed by High-Pressure Abrasive Water Jet.

Science.gov (United States)

Kang, Can; Liu, Haixia

2013-08-14

Being subjected to a high-pressure abrasive water jet, solid samples will experience an essential variation of both internal stress and physical characteristics, which is closely associated with the kinetic energy attached to the abrasive particles involved in the jet stream. Here, experiments were performed, with particular emphasis being placed on the kinetic energy attenuation and turbulent features in the jet stream. At jet pressure of 260 MPa, mean velocity and root-mean-square (RMS) velocity on two jet-stream sections were acquired by utilizing the phase Doppler anemometry (PDA) technique. A jet-cutting experiment was then carried out with Al-Mg alloy samples being cut by an abrasive water jet. Morphological features and roughness on the cut surface were quantitatively examined through scanning electron microscopy (SEM) and optical profiling techniques. The results indicate that the high-pressure water jet is characterized by remarkably high mean flow velocities and distinct velocity fluctuations. Those irregular pits and grooves on the cut surfaces indicate both the energy attenuation and the development of radial velocity components in the jet stream. When the sample is positioned with different distances from the nozzle outlet, the obtained quantitative surface roughness varies accordingly. A descriptive model highlighting the behaviors of abrasive particles in jet-cutting process is established in light of the experimental results and correlation analysis.

UMTRA project technical assistance contractor quality assurance implementation plan for surface and ground water

International Nuclear Information System (INIS)

1994-09-01

The Uranium Mill Tailings Remedial Action (UMTRA) Project Technical Assistance Contractor (TAC) Quality Assurance Implementation Plan (QAIP) outlines the primary requirements for integrating quality functions for TAC technical activities applied to the surface and ground water phases of the UMTRA Project. The QAIP is subordinate to the latest issue of the UMTRA Project TAC Quality Assurance Program Plan (QAPP). The QAIP addresses technical aspects of the TAC UMTRA Project surface and ground water programs. The QAIP is authorized and approved by the TAC Project Manager and QA manager. The QA program is designed to use monitoring, audit, and surveillance functions as management tools to ensure that all Project organization activities are carried out in a manner that will protect public health and safety, promote the success of the UMTRA Project and meet or exceed contract requirements

30 CFR 795.11 - Assistance funding.

Science.gov (United States)

2010-07-01

... Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR SMALL OPERATOR ASSISTANCE PERMANENT REGULATORY PROGRAM-SMALL OPERATOR ASSISTANCE PROGRAM § 795.11 Assistance... eligible small operators if available funds are less than those required to provide the services pursuant...

HREEL study of c(53x9)rect-N structure on Ni(111) surface

International Nuclear Information System (INIS)

Papagno, M.; Pacile, D.; Giallombardo, C.; Cupolillo, A.; Papagno, L.

2005-01-01

In this work we have prepared and characterized by low energy electron diffraction (LEED) and high-resolution electron energy loss spectroscopy (HREELS) the Ni(111)-c(53x9)rect-N surface structure formed by saturating the Ni(111) surface with nitrogen atoms. This structure was obtained by the ion-gauge assisted N 2 exposure method. The loss spectra show features at 50 and 25meV assigned to the N-Ni vibration and to a phonon of the reconstructed surface, respectively. We also investigated the case in which the Ni(111) surface was covered with a low coverage of N atoms

Dynamics of Soil Deflation Features in Kangerlussuaq, Greenland Revealed by Variations in Lichen Diameters on Exposed Surfaces

Science.gov (United States)

Heindel, R. C.; Kelly, M. A.; Virginia, R. A.

2013-12-01

Little is known about the pervasive soil deflation features in the Kangerlussuaq region, West Greenland, an area deglaciated between ~6,800 and 150 years ago. While the majority of the landscape is vegetated with low-lying shrubs and graminoids, wind erosion has removed loess and vegetation from distinct patches ranging in size from a few to tens of meters across, leaving the underlying glacial till or bedrock exposed. Although previous work has considered aeolian landforms and regional loess deposition along the Watson River Valley, these deflation features have not been investigated in detail. We aim to determine both the timing and mechanisms of formation of the deflation features and will examine whether these mechanisms were related to regional climatic conditions, such as increased aridity, to fluctuations in the Greenland Ice Sheet, or to other factors. Our ongoing research investigating these features includes geomorphic mapping using field observations and satellite imagery, lichenometry of the exposed surfaces, and cosmogenic nuclide dating of boulders and bedrock within and near the deflation features. Here we present initial results from our lichenometry studies. During the summer of 2013, we measured maximum lichen (Rhizocarpon sp.) diameters on boulder and bedrock surfaces in 15 soil deflation features located between Kangerlussuaq and the ice sheet margin. Lichen diameters vary from only a few millimeters at the outer margins of deflation features to multiple centimeters (maximum ~50 mm) in the centers of the unvegetated patches. This distinct pattern suggests that the outer margins of the soil deflation features are currently active. Based on a previously established lichen growth curve for Rhizocarpon sp. in West Greenland, our results indicate that the features are expanding at a rate of ~1.5 m per 100 yrs. In addition, the large lichen diameters (~40-50 mm) that occur in the centers of deflation features suggest that the formation mechanism has

Linear and Nonlinear Gait Features in Older Adults Walking on Inclined Surfaces at Different Speeds.

Science.gov (United States)

Vieira, Marcus Fraga; Rodrigues, Fábio Barbosa; de Sá E Souza, Gustavo Souto; Magnani, Rina Márcia; Lehnen, Georgia Cristina; Andrade, Adriano O

2017-06-01

This study evaluated linear and nonlinear gait features in healthy older adults walking on inclined surfaces at different speeds. Thirty-seven active older adults (experimental group) and fifty young adults (control group) walked on a treadmill at 100% and ±20% of their preferred walking speed for 4 min under horizontal (0%), upward (UP) (+8%), and downward (DOWN) (-8%) conditions. Linear gait variability was assessed using the average standard deviation of trunk acceleration between strides (VAR). Gait stability was assessed using the margin of stability (MoS). Nonlinear gait features were assessed by using the maximum Lyapunov exponent, as a measure of local dynamic stability (LDS), and sample entropy (SEn), as a measure of regularity. VAR increased for all conditions, but the interaction effects between treadmill inclination and age, and speed and age were higher for young adults. DOWN conditions showed the lowest stability in the medial-lateral MoS, but not in LDS. LDS was smaller in UP conditions. However, there were no effects of age for either MoS or LDS. The values of SEn decreased almost linearly from the DOWN to the UP conditions, with significant interaction effects of age for anterior-posterior SEn. The overall results supported the hypothesis that inclined surfaces modulate nonlinear gait features and alter linear gait variability, particularly in UP conditions, but there were no significant effects of age for active older adults.

Comparison of Surface Flow Features from Lidar-Derived Digital Elevation Models with Historical Elevation and Hydrography Data for Minnehaha County, South Dakota

Science.gov (United States)

Poppenga, Sandra K.; Worstell, Bruce B.; Stoker, Jason M.; Greenlee, Susan K.

2009-01-01

The U.S. Geological Survey (USGS) has taken the lead in the creation of a valuable remote sensing product by incorporating digital elevation models (DEMs) derived from Light Detection and Ranging (lidar) into the National Elevation Dataset (NED), the elevation layer of 'The National Map'. High-resolution lidar-derived DEMs provide the accuracy needed to systematically quantify and fully integrate surface flow including flow direction, flow accumulation, sinks, slope, and a dense drainage network. In 2008, 1-meter resolution lidar data were acquired in Minnehaha County, South Dakota. The acquisition was a collaborative effort between Minnehaha County, the city of Sioux Falls, and the USGS Earth Resources Observation and Science (EROS) Center. With the newly acquired lidar data, USGS scientists generated high-resolution DEMs and surface flow features. This report compares lidar-derived surface flow features in Minnehaha County to 30- and 10-meter elevation data previously incorporated in the NED and ancillary hydrography datasets. Surface flow features generated from lidar-derived DEMs are consistently integrated with elevation and are important in understanding surface-water movement to better detect surface-water runoff, flood inundation, and erosion. Many topographic and hydrologic applications will benefit from the increased availability of accurate, high-quality, and high-resolution surface-water data. The remotely sensed data provide topographic information and data integration capabilities needed for meeting current and future human and environmental needs.

Virtual laparoscopy: Initial experience with three-dimensional ultrasonography to characterize hepatic surface features

International Nuclear Information System (INIS)

Sekimoto, Tadashi; Maruyama, Hitoshi; Kondo, Takayuki; Shimada, Taro; Takahashi, Masanori; Yokosuka, Osamu; Otsuka, Masayuki; Miyazaki, Masaru; Mine, Yoshitaka

2013-01-01

Objective: To examine the potential utility of 3D-reconstructed sonograms to distinguish cirrhotic from non-cirrhotic livers by demonstrating hepatic surface characteristics. Materials and methods: A preliminary phantom study was performed to examine the potential resolution of 3D images, recognizing surface irregularities as a difference in height. In a prospective clinical study of 31 consecutive patients with ascites (21 cirrhosis, 10 non-cirrhosis), liver volume data were acquired by transabdominal mechanical scanning. The hepatic surface features of cirrhotic and non-cirrhotic patients were compared by 2 independent reviewers. Intra- and inter-operator/reviewer agreements were also examined. Results: The phantom study revealed that 0.4 mm was the minimum recognizable difference in height on the 3D sonograms. The hepatic surface image was successfully visualized in 74% patients (23/31). Success depended on the amount of ascites; visualization was 100% with ascites of 10 mm or more between the hepatic surface and abdominal wall. The images showed irregularity of the hepatic surface in all cirrhotic patients. The surface appearance was confirmed as being very similar in 3 patients who had both 3D sonogram and liver resection for transplantation. The ability to distinguish cirrhotic liver from non-cirrhotic liver improved with the use of combination of 2D- and 3D-imaging versus 2D-imaging alone (sensitivity, p = 0.02; accuracy, p = 0.02) or 3D-imaging alone (sensitivity, p = 0.03). Intra-/inter-operator and inter-reviewer agreement were excellent (κ = 1.0). Conclusion: 3D-based sonographic visualization of the hepatic surface showed high reliability and reproducibility, acting as a virtual laparoscopy method, and the technique has the potential to improve the diagnosis of cirrhosis

Comparison of Cellular Alterations in Fat Cells Harvested With Laser-Assisted Liposuction and Suction-Assisted Liposuction.

Science.gov (United States)

Yildiz, Kemalettin; Taşli, Pakize Neslihan; Şahin, Fikrettin; Güneren, Ethem

2016-05-01

The aim of the present study was to evaluate the viability and proliferative capacity of adipose-derived stem cells obtained by laser-assisted liposuction (LAL). Fat tissue was obtained from 7 male patients treated surgically for gynecomastia. On one side, harvesting was made before LAL, while it was implemented after LAL on the contralateral side. Viability, cell surface antigens, pluripotency, and apoptosis were assessed and compared in these samples. Cells harvested before and after LAL did not exhibit any significant difference in terms of surface cell markers. Number of viable stem cells was lower initially after exposure to laser, while this difference was reversed at the end of 72 hours. Genetic indicators of cellular differentiation were similar in both groups. Apoptosis indicators were increased remarkably after laser exposure in the first 24 hours, but this increase was absent 72 hours after LAL procedure. The authors' results have promising clinical relevance since mesenchymal stem cells harvested during LAL have maintained appropriate cellular features to be used for autologous fat transfer and fat grafting.

Surface Replication of Molded Products with Microneedle Features in Injection Molding

Science.gov (United States)

Uchiumi, Kazuyasu; Takayama, Tetsuo; Ito, Hiroshi; Inou, Akinori

Micro-molding of microneedle features was conducted using several injection-molding techniques. Injection compression molding and injection molding were performed with supercritical carbon dioxide fluid and with or without vacuum processing inside the mold cavity. Effects of process parameters on processability and surface replication of the molded parts were evaluated. The height replication ratio for microneedles was improved using injection compression molding. At a shorter compression stroke, the needle height was improved, and the influence of compression delay time was also small. Moreover, the effects of vacuum processing inside the mold cavity under the filling process were slight. The height replication ratio for microneedles showed the highest values using injection molding using supercritical carbon dioxide fluid with vacuum inside the mold cavity.

Machine-assisted verification of latent fingerprints: first results for nondestructive contact-less optical acquisition techniques with a CWL sensor

Science.gov (United States)

Hildebrandt, Mario; Kiltz, Stefan; Krapyvskyy, Dmytro; Dittmann, Jana; Vielhauer, Claus; Leich, Marcus

2011-11-01

A machine-assisted analysis of traces from crime scenes might be possible with the advent of new high-resolution non-destructive contact-less acquisition techniques for latent fingerprints. This requires reliable techniques for the automatic extraction of fingerprint features from latent and exemplar fingerprints for matching purposes using pattern recognition approaches. Therefore, we evaluate the NIST Biometric Image Software for the feature extraction and verification of contact-lessly acquired latent fingerprints to determine potential error rates. Our exemplary test setup includes 30 latent fingerprints from 5 people in two test sets that are acquired from different surfaces using a chromatic white light sensor. The first test set includes 20 fingerprints on two different surfaces. It is used to determine the feature extraction performance. The second test set includes one latent fingerprint on 10 different surfaces and an exemplar fingerprint to determine the verification performance. This utilized sensing technique does not require a physical or chemical visibility enhancement of the fingerprint residue, thus the original trace remains unaltered for further investigations. No particular feature extraction and verification techniques have been applied to such data, yet. Hence, we see the need for appropriate algorithms that are suitable to support forensic investigations.

Meteorological data for four sites at surface-disruption features in Yucca Flat, Nevada Test Site, Nye County, Nevada, 1985--1986

International Nuclear Information System (INIS)

Carman, R.L.

1994-01-01

Surface-disruption features, or craters, resulting from underground nuclear testing at the Nevada Test Site may increase the potential for ground-water recharge in an area that would normally produce little, if any, recharge. This report presents selected meteorological data resulting from a study of two surface-disruption features during May 1985 through June 1986. The data were collected at four adjacent sites in Yucca Flat, about 56 kilometers north of Mercury, Nevada. Three sites (one in each of two craters and one at an undisturbed site at the original land surface) were instrumented to collect meteorological data for calculating bare-soil evaporation. These data include (1) long-wave radiation, (2) short-wave radiation, (3) net radiation, (4) air temperature, and (5) soil surface temperature. Meteorological data also were collected at a weather station at an undisturbed site near the study craters. Data collected at this site include (1) air temperature, (2) relative humidity, (3) wind velocity, and (4) wind direction

Plasma assisted surface treatments of biomaterials.

Science.gov (United States)

Minati, L; Migliaresi, C; Lunelli, L; Viero, G; Dalla Serra, M; Speranza, G

2017-10-01

The biocompatibility of an implant depends upon the material it is composed of, in addition to the prosthetic device's morphology, mechanical and surface properties. Properties as porosity and pore size should allow, when required, cells penetration and proliferation. Stiffness and strength, that depend on the bulk characteristics of the material, should match the mechanical requirements of the prosthetic applications. Surface properties should allow integration in the surrounding tissues by activating proper communication pathways with the surrounding cells. Bulk and surface properties are not interconnected, and for instance a bone prosthesis could possess the necessary stiffness and strength for the application omitting out prerequisite surface properties essential for the osteointegration. In this case, surface treatment is mandatory and can be accomplished using various techniques such as applying coatings to the prosthesis, ion beams, chemical grafting or modification, low temperature plasma, or a combination of the aforementioned. Low temperature plasma-based techniques have gained increasing consensus for the surface modification of biomaterials for being effective and competitive compared to other ways to introduce surface functionalities. In this paper we review plasma processing techniques and describe potentialities and applications of plasma to tailor the interface of biomaterials. Copyright © 2017 Elsevier B.V. All rights reserved.

Crystal structure and nanotopographical features on the surface of heat-treated and anodized porous titanium biomaterials produced using selective laser melting

Energy Technology Data Exchange (ETDEWEB)

Amin Yavari, S., E-mail: s.aminyavari@tudelft.nl [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); FT Innovations BV, Braamsluiper 1, 5831 PW Boxmeer (Netherlands); Wauthle, R. [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); LayerWise NV, Kapeldreef 60, Leuven (Belgium); Böttger, A.J. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Schrooten, J. [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44 PB 2450, 3001 Heverlee (Belgium); Weinans, H. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Department of Orthopedics and Department of Rheumatology, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Zadpoor, A.A. [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

2014-01-30

Porous titanium biomaterials manufactured using additive manufacturing techniques such as selective laser melting are considered promising materials for orthopedic applications where the biomaterial needs to mimic the properties of bone. Despite their appropriate mechanical properties and the ample pore space they provide for bone ingrowth and osseointegration, porous titanium structures have an intrinsically bioinert surface and need to be subjected to surface bio-functionalizing procedures to enhance their in vivo performance. In this study, we used a specific anodizing process to build a hierarchical oxide layer on the surface of porous titanium structures made by selective laser melting of Ti6Al4V ELI powder. The hierarchical structure included both nanotopographical features (nanotubes) and micro-features (micropits). After anodizing, the biomaterial was heat treated in Argon at different temperatures ranging between 400 and 600 °C for either 1 or 2 h to improve its bioactivity. The effects of applied heat treatment on the crystal structure of TiO{sub 2} nanotubes and the nanotopographical features of the surface were studied using scanning electron microscopy and X-ray diffraction. It was shown that the transition from the initial crystal structure, i.e. anatase, to rutile occurs between 500 and 600 °C and that after 2 h of heat treatment at 600 °C the crystal structure is predominantly rutile. The nanotopographical features of the surface were found to be largely unchanged for heat treatments carried out at 500 °C or below, whereas they were partially or largely disrupted after heat treatment at 600 °C. The possible implications of these findings for the bioactivity of porous titanium structures are discussed.

Replication of micro and nano-features on iPP by injection molding with fast cavity surface temperature evolution

DEFF Research Database (Denmark)

Speranzaa, Vito; Liparotia, Sara; Calaon, Matteo

2017-01-01

The production of polymeric components with functional structures in the micrometer and sub-micrometer range is a complex challenge for the injection molding process, since it suffers the use of low cavity surface temperatures that induce the fast formation of a frozen layer, thus preventing...... was sufficient to obtain accurate replication, with adequate surface temperatures. In the case of nano-features, the replication accuracy was affected by the morphology developed on the molding surface, that is aligned along the flow direction with dimensions comparable with the dimension of the nano...

UV irradiation assisted growth of ZnO nanowires on optical fiber surface

Energy Technology Data Exchange (ETDEWEB)

Gong, Bo; Shi, Tielin; Liao, Guanglan; Li, Xiaoping; Huang, Jie; Zhou, Temgyuan; Tang, Zirong, E-mail: zirong@mail.hust.edu.cn

2017-06-01

Highlights: • A new fabrication process combined a hydrothermal process with UV irradiation from optical fiber is developed. • The growth of ZnO nanowires is efficient in the utilization of UV light. • A novel hybrid structure which integrates ZnO nanowires on optical fiber surface is synthesized. • The UV assisted growth of ZnO nanowires shows preferred orientation and better quality. • A mechanism of growing ZnO nanowires under UV irradiation is proposed. - Abstract: In this paper, a novel approach was developed for the enhanced growth of ZnO nanowires on optical fiber surface. The method combined a hydrothermal process with the efficient UV irradiation from the fiber core, and the effects of UV irradiation on the growth behavior of ZnO nanowires were investigated. The results show that UV irradiation had great effects on the preferred growth orientation and the quality of the ZnO nanowires. The crystallization velocity along the c-axis would increase rapidly with the increase of the irradiation power, while the growth process in the lateral direction was marginally affected by the irradiation. The structure of ZnO nanowires also shows less oxygen vacancy with UV irradiation of higher power. The developed approach is applicable for the efficient growth of nanowires on the fiber surface, and the ZnO nanowires/optical fiber hybrid structures have great potentials for a wide variety of applications such as optical fiber sensors and probes.

Transforming a Simple Commercial Glue into Highly Robust Superhydrophobic Surfaces via Aerosol-Assisted Chemical Vapor Deposition.

Science.gov (United States)

Zhuang, Aoyun; Liao, Ruijin; Lu, Yao; Dixon, Sebastian C; Jiamprasertboon, Arreerat; Chen, Faze; Sathasivam, Sanjayan; Parkin, Ivan P; Carmalt, Claire J

2017-12-06

Robust superhydrophobic surfaces were synthesized as composites of the widely commercially available adhesives epoxy resin (EP) and polydimethylsiloxane (PDMS). The EP layer provided a strongly adhered micro/nanoscale structure on the substrates, while the PDMS was used as a post-treatment to lower the surface energy. In this study, the depositions of EP films were taken at a range of temperatures, deposition times, and substrates via aerosol-assisted chemical vapor deposition (AACVD). A novel dynamic deposition temperature approach was developed to create multiple-layered periodic micro/nanostructures that significantly improved the surface mechanical durability. Water droplet contact angles (CA) of 160° were observed with droplet sliding angles (SA) frequently UV testing (365 nm, 3.7 mW/cm 2 , 120 h) were carried out to exhibit the environmental stability of the films. Self-cleaning behavior was demonstrated in clearing the surfaces of various contaminating powders and aqueous dyes. This facile and flexible method for fabricating highly durable superhydrophobic polymer films points to a promising future for AACVD in their scalable and low-cost production.

Off-Center Rotation of CuPc Molecular Rotor on a Bi(111) Surface and the Chiral Feature.

Science.gov (United States)

Sun, Kai; Tao, Min-Long; Tu, Yu-Bing; Wang, Jun-Zhong

2017-05-04

Molecular rotors with an off-center axis and the chiral feature of achiral CuPc molecules on a semi-metallic Bi(111) surface have been investigated by means of a scanning tunneling microscopy (STM) at liquid nitrogen (LN₂) temperature. The rotation axis of each CuPc molecular rotor is located at the end of a phthalocyanine group. As molecular coverage increases, the CuPc molecules are self-assembled into various nanoclusters and finally into two-dimensional (2D) domains, in which each CuPc molecule exhibits an apparent chiral feature. Such chiral features of the CuPc molecules can be attributed to the combined effect of asymmetric charge transfer between the CuPc and Bi(111) substrate, and the intermolecular van der Waals interactions.

Examining the Impact of Question Surface Features on Students’ Answers to Constructed-Response Questions on Photosynthesis

Science.gov (United States)

Weston, Michele; Haudek, Kevin C.; Prevost, Luanna; Urban-Lurain, Mark; Merrill, John

2015-01-01

One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of two question prompts. We asked four versions of the question with different combinations of the two plant species and order of prompts in an introductory cell biology course. We found that there was not a significant difference in the content of student responses to versions of the question stem with different species or order of prompts, using both computerized lexical analysis and expert scoring. We conducted 20 face-to-face interviews with students to further probe the effects of question wording on student responses. During the interviews, we found that students thought that the plant species was neither relevant nor confusing when answering the question. Students identified the prompts as both relevant and confusing. However, this confusion was not specific to a single version. PMID:25999312

Water surface assisted synthesis of large-scale carbon nanotube film for high-performance and stretchable supercapacitors.

Science.gov (United States)

Yu, Minghao; Zhang, Yangfan; Zeng, Yinxiang; Balogun, Muhammad-Sadeeq; Mai, Kancheng; Zhang, Zishou; Lu, Xihong; Tong, Yexiang

2014-07-16

A kind of multiwalled carbon-nanotube (MWCNT)/polydimethylsiloxane (PDMS) film with excellent conductivity and mechanical properties is developed using a facile and large-scale water surface assisted synthesis method. The film can act as a conductive support for electrochemically active PANI nano fibers. A device based on these PANI/MWCNT/PDMS electrodes shows good and stable capacitive behavior, even under static and dynamic stretching conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vitro bioactivity of micro metal injection moulded stainless steel with defined surface features

Directory of Open Access Journals (Sweden)

C Brose

2012-05-01

Full Text Available Micrometre- and nanometre-scale surface structuring with ordered topography features may dramatically enhance orthopaedic implant integration. In this study we utilised a previously optimised micron metal injection moulding (µ-MIM process to produce medical grade stainless steel surfaces bearing micrometre scale, protruding, hemispheres of controlled dimensions and spatial distribution. Additionally, the structured surfaces were characterised by the presence of submicrometre surface roughness resulting from metal grain boundary formation. Following cytocompatibility (cytotoxicity evaluation using 3T3 mouse fibroblast cell line, the effect on primary human cell functionality was assessed focusing on cell attachment, shape and cytoskeleton conformation. In this respect, and by day 7 in culture, significant increase in focal adhesion size was associated with the microstructured surfaces compared to the planar control. The morphological conformation of the seeded cells, as revealed by fluorescence cytoskeleton labelling, also appeared to be guided in the vertical dimension between the hemisphere bodies. Quantitative evaluation of this guidance took place using live cytoplasm fluorescence labelling and image morphometry analysis utilising both, compactness and elongation shape descriptors. Significant increase in cell compactness was associated with the hemisphere arrays indicating collective increase in focused cell attachment to the hemisphere bodies across the entire cell population. Micrometre-scale hemisphere array patterns have therefore influenced cell attachment and conformation. Such influence may potentially aid in enhancing key cellular events such as, for example, neo-osteogenesis on implanted orthopaedic surfaces.

Analysis of Contemporary Methods for Designing Rotary Type Ventricular Assist Devices

Directory of Open Access Journals (Sweden)

E. P. Banin

2015-01-01

Full Text Available The research object is inlet apparatus of ventricular assist device, namely inlet cannula and straightener.The purpose of the study is to reveal features of blood flow in inlet apparatus of ventricular assist device. The mathematical modeling is carried out by computational fluid dynamics analysis in a stationary setting.The first part of study concerns the analysis of existing approaches to the numerical and experimental studies in designing the ventricular assist devices of rotary type. It reveals the features of each approach for their further application in practice. The article presents an original design of developed hydraulic test bench to verify the results of mathematical modeling. Analysis of foreign authors’ studies showed that there is no enough attention paid to design of the adjacent pump assemblies of ventricular assist device. The second part of study considers direct mathematical modeling of input apparatus of ventricular assist device. The study examined straightener with three or four blades. Mathematical modeling has revealed the presence of potentially dangerous stagnation zones and essential asymmetry of the outlet flow from the input unit. The found features must be taken in consideration in designing the ventricular assist device pumps. In the future we plan to use obtained data to create a parametric model of the rotor and the diffuser considering the abovementioned features.

User-assisted video segmentation system for visual communication

Science.gov (United States)

Wu, Zhengping; Chen, Chun

2002-01-01

Video segmentation plays an important role for efficient storage and transmission in visual communication. In this paper, we introduce a novel video segmentation system using point tracking and contour formation techniques. Inspired by the results from the study of the human visual system, we intend to solve the video segmentation problem into three separate phases: user-assisted feature points selection, feature points' automatic tracking, and contour formation. This splitting relieves the computer of ill-posed automatic segmentation problems, and allows a higher level of flexibility of the method. First, the precise feature points can be found using a combination of user assistance and an eigenvalue-based adjustment. Second, the feature points in the remaining frames are obtained using motion estimation and point refinement. At last, contour formation is used to extract the object, and plus a point insertion process to provide the feature points for next frame's tracking.

Microstructural features of environmentally assisted cracking in pipeline steel

International Nuclear Information System (INIS)

Williams, B.W.; Lambert, S.B.; Zhang, X.; Plumtree, A.; Sutherby, R.

2003-01-01

A number of small-scale pipeline specimens containing edge or surface cracks were tested in simulated groundwater (NS4 solution) in an anaerobic environment under cyclic loading conditions. Micrographs of the crack surface showed corrosion fatigue at high frequencies and low R-ratios. Following large amounts of growth (∼200 μm) for those specimens tested at low frequencies, evidence of transgranular quasi-cleavage was detected. Green rust was found to be present at the crack tips and along their flanks. Iron sulfide, resulting from anaerobic sulfate-reducing bacteria and iron carbonate were also present in the NS4 solution during testing. These corrosion products retarded crack growth in the depth direction of surface cracks. Under variable amplitude loadings conditions, the accompanying increased surface crack growth rate can be accounted for by rupture of the green rust film at the crack tip. (author)

Surface morphology of thin lysozyme films produced by matrix-assisted pulsed laser evaporation (MAPLE)

DEFF Research Database (Denmark)

Purice, Andreea; Schou, Jørgen; Pryds, Nini

2007-01-01

Thin films of the protein, lysozyme, have been deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. Frozen targets of 0.3-1.0 wt.% lysozyme dissolved in ultrapure water were irradiated by laser light at 355 mn with a fluence of 2 J/cm(2). The surface quality of the thin....... The concentration of lysozyme in the ice matrix apparently does not play any significant role for the morphology of the film. The morphology obtained with MAPLE has been compared with results for direct laser irradiation of a pressed lysozyme sample (i.e. pulsed laser deposition (PLD)). (C) 2007 Elsevier B.V. All...

Analysis of progression of fatigue conditions in biceps brachii muscles using surface electromyography signals and complexity based features.

Science.gov (United States)

Karthick, P A; Makaram, Navaneethakrishna; Ramakrishnan, S

2014-01-01

Muscle fatigue is a neuromuscular condition where muscle performance decreases due to sustained or intense contraction. It is experienced by both normal and abnormal subjects. In this work, an attempt has been made to analyze the progression of muscle fatigue in biceps brachii muscles using surface electromyography (sEMG) signals. The sEMG signals are recorded from fifty healthy volunteers during dynamic contractions under well defined protocol. The acquired signals are preprocessed and segmented in to six equal parts for further analysis. The features, such as activity, mobility, complexity, sample entropy and spectral entropy are extracted from all six zones. The results are found showing that the extracted features except complexity feature have significant variations in differentiating non-fatigue and fatigue zone respectively. Thus, it appears that, these features are useful in automated analysis of various neuromuscular activities in normal and pathological conditions.

Modification of the large-scale features of high Reynolds number wall turbulence by passive surface obtrusions

Energy Technology Data Exchange (ETDEWEB)

Monty, J.P.; Lien, K.; Chong, M.S. [University of Melbourne, Department of Mechanical Engineering, Parkville, VIC (Australia); Allen, J.J. [New Mexico State University, Department of Mechanical Engineering, Las Cruces, NM (United States)

2011-12-15

A high Reynolds number boundary-layer wind-tunnel facility at New Mexico State University was fitted with a regularly distributed braille surface. The surface was such that braille dots were closely packed in the streamwise direction and sparsely spaced in the spanwise direction. This novel surface had an unexpected influence on the flow: the energy of the very large-scale features of wall turbulence (approximately six-times the boundary-layer thickness in length) became significantly attenuated, even into the logarithmic region. To the author's knowledge, this is the first experimental study to report a modification of 'superstructures' in a rough-wall turbulent boundary layer. The result gives rise to the possibility that flow control through very small, passive surface roughness may be possible at high Reynolds numbers, without the prohibitive drag penalty anticipated heretofore. Evidence was also found for the uninhibited existence of the near-wall cycle, well known to smooth-wall-turbulence researchers, in the spanwise space between roughness elements. (orig.)

Development of a Feature and Template-Assisted Assembler and Application to the Analysis of a Foot-and-Mouth Disease Virus Genotyping Microarray.

Directory of Open Access Journals (Sweden)

Roger W Barrette

Full Text Available Several RT-PCR and genome sequencing strategies exist for the resolution of Foot-and-Mouth Disease virus (FMDV. While these approaches are relatively straightforward, they can be vulnerable to failure due to the unpredictable nature of FMDV genome sequence variations. Sequence independent single primer amplification (SISPA followed by genotyping microarray offers an attractive unbiased approach to FMDV characterization. Here we describe a custom FMDV microarray and a companion feature and template-assisted assembler software (FAT-assembler capable of resolving virus genome sequence using a moderate number of conserved microarray features. The results demonstrate that this approach may be used to rapidly characterize naturally occurring FMDV as well as an engineered chimeric strain of FMDV. The FAT-assembler, while applied to resolving FMDV genomes, represents a new bioinformatics approach that should be broadly applicable to interpreting microarray genotyping data for other viruses or target organisms.

An investigation into the effective surface passivation of quantum dots by a photo-assisted chemical method

Directory of Open Access Journals (Sweden)

So-Yeong Joo

2018-01-01

Full Text Available In this study, we have developed an effective amino passivation process for quantum dots (QDs at room temperature and have investigated a passivation mechanism using a photo-assisted chemical method. As a result of the reverse reaction of the H2O molecules, the etching kinetics of the photo-assisted chemical method increased upon increasing the 3-amino-1-propanol (APOL/H2O ratio of the etching solution. Photon-excited electron-hole pairs lead to strong bonding between the organic and surface atoms of the QDs, and results in an increase of the quantum yield (QY%. This passivation method is also applicable to CdSe/ZnSe core/shell structures of QDs, due to the passivation of mid-gap defects states at the interface. The QY% of the as-synthesized CdSe QDs is dramatically enhanced by the amino passivation from 37% to 75% and the QY% of the CdSe/ZnSe core/shell QDs is also improved by ∼28%.

The role of alternating current in photo-assisted electrochemical porosification of GaN

International Nuclear Information System (INIS)

Ainorkhilah, Mahmood; Naser, M. Ahmed; Yushamdan, Yusof; Kwong, Yam Fong; Zainuriah, Hassan; Tiginyanu, Ion; Siang, Chuah Lee

2013-01-01

In this paper, we report the formation of porous GaN films under a novel alternating current (sine-wave a.c. (50 Hz)) photo-assisted electrochemical (ACPEC) etching conditions. The ACPEC formed porous GaN with excellent structural and surface morphology. Field emission scanning electron microscope (FESEM), atomic force microscopy (AFM) and high resolution X-ray diffraction (HR-XRD) phi-scan and rocking curves measurements evidenced important features of the pore morphology and nanostructures. According to the FESEM micrographs, the spatial nano architecture of the porous structures exhibits pores with perfect hexagonal shape. The AFM measurements revealed an increase in the surface roughness induced by porosification. X-ray diffraction phi-scan showed that porous GaN sample maintained the epitaxial. (authors)

Diagnostics of microwave assisted electron cyclotron resonance plasma source for surface modification of nylon 6

Science.gov (United States)

More, Supriya E.; Das, Partha Sarathi; Bansode, Avinash; Dhamale, Gayatri; Ghorui, S.; Bhoraskar, S. V.; Sahasrabudhe, S. N.; Mathe, Vikas L.

2018-01-01

Looking at the increasing scope of plasma processing of materials surface, here we present the development and diagnostics of a microwave assisted Electron Cyclotron Resonance (ECR) plasma system suitable for surface modification of polymers. Prior to the surface-treatment, a detailed diagnostic mapping of the plasma parameters throughout the reactor chamber was carried out by using single and double Langmuir probe measurements in Ar plasma. Conventional analysis of I-V curves as well as the elucidation form of the Electron Energy Distribution Function (EEDF) has become the source of calibration of plasma parameters in the reaction chamber. The high energy tail in the EEDF of electron temperature is seen to extend beyond 60 eV, at much larger distances from the ECR zone. This proves the suitability of the rector for plasma processing, since the electron energy is much beyond the threshold energy of bond breaking in most of the polymers. Nylon 6 is used as a representative candidate for surface processing in the presence of Ar, H2 + N2, and O2 plasma, treated at different locations inside the plasma chamber. In a typical case, the work of adhesion is seen to almost get doubled when treated with oxygen plasma. Morphology of the plasma treated surface and its hydrophilicity are discussed in view of the variation in electron density and electron temperature at these locations. Nano-protrusions arising from plasma treatment are set to be responsible for the hydrophobicity. Chemical sputtering and physical sputtering are seen to influence the surface morphology on account of sufficient electron energies and increased plasma potential.

Development of Functional Surfaces on High-Density Polyethylene (HDPE) via Gas-Assisted Etching (GAE) Using Focused Ion Beams.

Science.gov (United States)

Sezen, Meltem; Bakan, Feray

2015-12-01

Irradiation damage, caused by the use of beams in electron and ion microscopes, leads to undesired physical/chemical material property changes or uncontrollable modification of structures. Particularly, soft matter such as polymers or biological materials is highly susceptible and very much prone to react on electron/ion beam irradiation. Nevertheless, it is possible to turn degradation-dependent physical/chemical changes from negative to positive use when materials are intentionally exposed to beams. Especially, controllable surface modification allows tuning of surface properties for targeted purposes and thus provides the use of ultimate materials and their systems at the micro/nanoscale for creating functional surfaces. In this work, XeF2 and I2 gases were used in the focused ion beam scanning electron microscope instrument in combination with gallium ion etching of high-density polyethylene surfaces with different beam currents and accordingly different gas exposure times resulting at the same ion dose to optimize and develop new polymer surface properties and to create functional polymer surfaces. Alterations in the surface morphologies and surface chemistry due to gas-assisted etching-based nanostructuring with various processing parameters were tracked using high-resolution SEM imaging, complementary energy-dispersive spectroscopic analyses, and atomic force microscopic investigations.

Assistant Personal Robot (APR: Conception and Application of a Tele-Operated Assisted Living Robot

Directory of Open Access Journals (Sweden)

Eduard Clotet

2016-04-01

Full Text Available This paper presents the technical description, mechanical design, electronic components, software implementation and possible applications of a tele-operated mobile robot designed as an assisted living tool. This robotic concept has been named Assistant Personal Robot (or APR for short and has been designed as a remotely telecontrolled robotic platform built to provide social and assistive services to elderly people and those with impaired mobility. The APR features a fast high-mobility motion system adapted for tele-operation in plain indoor areas, which incorporates a high-priority collision avoidance procedure. This paper presents the mechanical architecture, electrical fundaments and software implementation required in order to develop the main functionalities of an assistive robot. The APR uses a tablet in order to implement the basic peer-to-peer videoconference and tele-operation control combined with a tactile graphic user interface. The paper also presents the development of some applications proposed in the framework of an assisted living robot.

Effect of l-lysine-assisted surface grafting for nano-hydroxyapatite on mechanical properties and in vitro bioactivity of poly(lactic acid-co-glycolic acid).

Science.gov (United States)

Liuyun, Jiang; Lixin, Jiang; Chengdong, Xiong; Lijuan, Xu; Ye, Li

2016-01-01

It is promising and challenging to study surface modification for nano-hydroxyapatite to improve the dispersion and enhance the mechanical properties and bioactivity of poly(lactic acid-co-glycolic acid). In this paper, we designed an effective new surface grafting with the assist of l-lysine for nano-hydroxyapatite, and the nano-hydroxyapatite surface grafted with the assist of l-lysine (g-nano-hydroxyapatite) was incorporated into poly(lactic acid-co-glycolic acid) to develop a series of g-nano-hydroxyapatite/poly(lactic acid-co-glycolic acid) nano-composites. The surface modification reaction for nano-hydroxyapatite, the mechanical properties, and in vitro human osteoblast-like cell (MG-63) response were characterized and investigated by Fourier transformation infrared, thermal gravimetric analysis, dispersion test, electromechanical universal tester, differential scanning calorimeter measurements, and in vitro cells culture experiment. The results showed that the grafting amount on the surface of nano-hydroxyapatite was enhanced with the increase of l-lysine, and the dispersion of nano-hydroxyapatite was improved more, so that it brought about better promotion crystallization and more excellent mechanical enhancement effect for poly(lactic acid-co-glycolic acid), comparing with the unmodified nano-hydroxyapatite. Moreover, the cells' attachment and proliferation results confirmed that the incorporation of the g-nano-hydroxyapatite into poly(lactic acid-co-glycolic acid) exhibited better biocompatibility than poly(lactic acid-co-glycolic acid). The above results indicated that the new surface grafting with the assist of l-lysine for nano-hydroxyapatite was an ideal novel surface modification method, which brought about better mechanical enhancement effect and in vitro bioactivity for poly(lactic acid-co-glycolic acid) with adding higher g-nano-hydroxyapatite content, suggesting it had a great potential to be used as bone fracture internal fixation materials

Colour marking of transparent materials by laser-induced plasma-assisted ablation (LIPAA)

International Nuclear Information System (INIS)

Hanada, Yasutaka; Sugioka, Koji; Miyamoto, Iwao; Midorikawa, Katsumi

2007-01-01

We demonstrate colour marking of a transparent material using laser-induced plasma-assisted ablation (LIPAA) system. After the LIPAA process, metal thin film is deposited on the surface of the ablated groove. This feature is applied to RGB (red, green and blue) colour marking by using specific metal targets. The metal targets, for instance, are Pb 3 O 4 for red, Cr 2 O 3 for green and [Cu(C 32 H 15 ClN 8 )] for blue colour marking. Additionally, adhesion of the metal thin film deposited on the processed groove by various experimental conditions is investigated

Cyclic Solvent Vapor Annealing for Rapid, Robust Vertical Orientation of Features in BCP Thin Films

Science.gov (United States)

Paradiso, Sean; Delaney, Kris; Fredrickson, Glenn

2015-03-01

Methods for reliably controlling block copolymer self assembly have seen much attention over the past decade as new applications for nanostructured thin films emerge in the fields of nanopatterning and lithography. While solvent assisted annealing techniques are established as flexible and simple methods for achieving long range order, solvent annealing alone exhibits a very weak thermodynamic driving force for vertically orienting domains with respect to the free surface. To address the desire for oriented features, we have investigated a cyclic solvent vapor annealing (CSVA) approach that combines the mobility benefits of solvent annealing with selective stress experienced by structures oriented parallel to the free surface as the film is repeatedly swollen with solvent and dried. Using dynamical self-consistent field theory (DSCFT) calculations, we establish the conditions under which the method significantly outperforms both static and cyclic thermal annealing and implicate the orientation selection as a consequence of the swelling/deswelling process. Our results suggest that CSVA may prove to be a potent method for the rapid formation of highly ordered, vertically oriented features in block copolymer thin films.

COMPUTER GRAPHICS MEETS IMAGE FUSION: THE POWER OF TEXTURE BAKING TO SIMULTANEOUSLY VISUALISE 3D SURFACE FEATURES AND COLOUR

Directory of Open Access Journals (Sweden)

G. J. Verhoeven

2017-08-01

Full Text Available Since a few years, structure-from-motion and multi-view stereo pipelines have become omnipresent in the cultural heritage domain. The fact that such Image-Based Modelling (IBM approaches are capable of providing a photo-realistic texture along the threedimensional (3D digital surface geometry is often considered a unique selling point, certainly for those cases that aim for a visually pleasing result. However, this texture can very often also obscure the underlying geometrical details of the surface, making it very hard to assess the morphological features of the digitised artefact or scene. Instead of constantly switching between the textured and untextured version of the 3D surface model, this paper presents a new method to generate a morphology-enhanced colour texture for the 3D polymesh. The presented approach tries to overcome this switching between objects visualisations by fusing the original colour texture data with a specific depiction of the surface normals. Whether applied to the original 3D surface model or a lowresolution derivative, this newly generated texture does not solely convey the colours in a proper way but also enhances the smalland large-scale spatial and morphological features that are hard or impossible to perceive in the original textured model. In addition, the technique is very useful for low-end 3D viewers, since no additional memory and computing capacity are needed to convey relief details properly. Apart from simple visualisation purposes, the textured 3D models are now also better suited for on-surface interpretative mapping and the generation of line drawings.

Computer Graphics Meets Image Fusion: the Power of Texture Baking to Simultaneously Visualise 3d Surface Features and Colour

Science.gov (United States)

Verhoeven, G. J.

2017-08-01

Since a few years, structure-from-motion and multi-view stereo pipelines have become omnipresent in the cultural heritage domain. The fact that such Image-Based Modelling (IBM) approaches are capable of providing a photo-realistic texture along the threedimensional (3D) digital surface geometry is often considered a unique selling point, certainly for those cases that aim for a visually pleasing result. However, this texture can very often also obscure the underlying geometrical details of the surface, making it very hard to assess the morphological features of the digitised artefact or scene. Instead of constantly switching between the textured and untextured version of the 3D surface model, this paper presents a new method to generate a morphology-enhanced colour texture for the 3D polymesh. The presented approach tries to overcome this switching between objects visualisations by fusing the original colour texture data with a specific depiction of the surface normals. Whether applied to the original 3D surface model or a lowresolution derivative, this newly generated texture does not solely convey the colours in a proper way but also enhances the smalland large-scale spatial and morphological features that are hard or impossible to perceive in the original textured model. In addition, the technique is very useful for low-end 3D viewers, since no additional memory and computing capacity are needed to convey relief details properly. Apart from simple visualisation purposes, the textured 3D models are now also better suited for on-surface interpretative mapping and the generation of line drawings.

Laser-assisted fabrication of materials

CERN Document Server

Manna, Indranil

2013-01-01

Laser assisted fabrication involves shaping of materials using laser as a source of heat. It can be achieved by removal of materials (laser assisted cutting, drilling, etc.), deformation (bending, extrusion), joining (welding, soldering) and addition of materials (surface cladding or direct laser cladding). This book on ´Laser assisted Fabrication’ is aimed at developing in-depth engineering concepts on various laser assisted macro and micro-fabrication techniques with the focus on application and a review of the engineering background of different micro/macro-fabrication techniques, thermal history of the treated zone and microstructural development and evolution of properties of the treated zone.

Design of electric-field assisted surface plasmon resonance system for the detection of heavy metal ions in water

Energy Technology Data Exchange (ETDEWEB)

Kyaw, Htet Htet [Department of Physics, College of Science, Sultan Qaboos University, P. O. Box 36, Al-Khoud 123 (Oman); Boonruang, Sakoolkan, E-mail: sakoolkan.boonruang@nectec.or.th, E-mail: waleed.m@bu.ac.th [Photonics Technology Laboratory, National Electronics and Computer Technology Center (NECTEC), 112 Thailand Science Park, PathumThani 12120 (Thailand); Mohammed, Waleed S., E-mail: sakoolkan.boonruang@nectec.or.th, E-mail: waleed.m@bu.ac.th [Center of Research in Optoelectronics, Communication and Control Systems (BUCROCCS), School of Engineering, Bangkok University, PathumThani 12120 (Thailand); Dutta, Joydeep [Functional Materials Division, School of Information and Communication Technology, KTH Royal Institute of Technology, Isafjordsgatan 22, SE-164 40 Kista, Stockholm (Sweden)

2015-10-15

Surface Plasmon Resonance (SPR) sensors are widely used in diverse applications. For detecting heavy metal ions in water, surface functionalization of the metal surface is typically used to adsorb target molecules, where the ionic concentration is detected via a resonance shift (resonance angle, resonance wavelength or intensity). This paper studies the potential of a possible alternative approach that could eliminate the need of using surface functionalization by the application of an external electric field in the flow channel. The exerted electrical force on the ions pushes them against the surface for enhanced adsorption; hence it is referred to as “Electric-Field assisted SPR system”. High system sensitivity is achieved by monitoring the time dynamics of the signal shift. The ion deposition dynamics are discussed using a derived theoretical model based on ion mobility in water. On the application of an appropriate force, the target ions stack onto the sensor surface depending on the ionic concentration of target solution, ion mass, and flow rate. In the experimental part, a broad detection range of target cadmium ions (Cd{sup 2+}) in water from several parts per million (ppm) down to a few parts per billion (ppb) can be detected.

Cloud and surface textural features in polar regions

Science.gov (United States)

Welch, Ronald M.; Kuo, Kwo-Sen; Sengupta, Sailes K.

1990-01-01

The study examines the textural signatures of clouds, ice-covered mountains, solid and broken sea ice and floes, and open water. The textural features are computed from sum and difference histogram and gray-level difference vector statistics defined at various pixel displacement distances derived from Landsat multispectral scanner data. Polar cloudiness, snow-covered mountainous regions, solid sea ice, glaciers, and open water have distinguishable texture features. This suggests that textural measures can be successfully applied to the detection of clouds over snow-covered mountains, an ability of considerable importance for the modeling of snow-melt runoff. However, broken stratocumulus cloud decks and thin cirrus over broken sea ice remain difficult to distinguish texturally. It is concluded that even with high spatial resolution imagery, it may not be possible to distinguish broken stratocumulus and thin clouds from sea ice in the marginal ice zone using the visible channel textural features alone.

Overseas Teachers and Assistants--Making Their Stay Worthwhile.

Science.gov (United States)

Wilson, James; Sarre, Winifred

1993-01-01

Presents general comments outlining the major features of the needs of teachers and assistants from overseas and discusses in-school needs and roles of such teachers and assistants separately. These comments touch on salary, social networks, family support, accommodation, general induction, the position of the native-speaking teacher, important…

UMTRA project technical assistance contractor quality assurance implementation plan for surface and ground water, Revision 2

International Nuclear Information System (INIS)

1995-11-01

This document contains the Technical Assistance Contractor (TAC) Quality Assurance Implementation Plan (QAIP) for the Uranium Mill Tailings Remedial Action (UMTRA) Project. The QAIP outlines the primary requirements for integrating quality functions for TAC technical activities applied to the surface and ground water phases of the UMTRA Project. The QA program is designed to use monitoring, audit, and surveillance activities as management tools to ensure that UMTRA Project activities are carried out in amanner to protect public health and safety, promote the success of the UMTRA Project, and meet or exceed contract requirements

Ballbot-type motion of N-heterocyclic carbenes on gold surfaces

Science.gov (United States)

Wang, Gaoqiang; Rühling, Andreas; Amirjalayer, Saeed; Knor, Marek; Ernst, Johannes Bruno; Richter, Christian; Gao, Hong-Jun; Timmer, Alexander; Gao, Hong-Ying; Doltsinis, Nikos L.; Glorius, Frank; Fuchs, Harald

2017-02-01

Recently, N-heterocyclic carbenes (NHCs) were introduced as alternative anchors for surface modifications and so offered many attractive features, which might render them superior to thiol-based systems. However, little effort has been made to investigate the self-organization process of NHCs on surfaces, an important aspect for the formation of self-assembled monolayers (SAMs), which requires molecular mobility. Based on investigations with scanning tunnelling microscopy and first-principles calculations, we provide an understanding of the microscopic mechanism behind the high mobility observed for NHCs. These NHCs extract a gold atom from the surface, which leads to the formation of an NHC-gold adatom complex that displays a high surface mobility by a ballbot-type motion. Together with their high desorption barrier this enables the formation of ordered and strongly bound SAMs. In addition, this mechanism allows a complementary surface-assisted synthesis of dimeric and hitherto unknown trimeric NHC gold complexes on the surface.

Glazed ceramic roof tiles: influence of surface features in the solar reflectance index

International Nuclear Information System (INIS)

Bortoli, Leitcia Silva de; Stapait, Camila Cristina; Marinoski, Deivis Luis; Fredel, Marcio Celso; Schabbach, Luciana M.

2016-01-01

In this study the influence of surface features of ceramic roof tiles in the solar reflectance index were evaluated. Two glazed ceramic roof tiles (type stoneware) with the same color (ivory) but with different appearance (matte and brilliant) were the focus of the analysis. The Solar Reflectance Index (SRI) of the roofs tiles were determined by the solar reflectance values (UV-VIS-NIR) and emittance, measured in laboratory. The samples showed SRI> 39 in accordance with LEED certification criteria (Leadership in Energy and Environmental Design), contributing to minimizing the Heat Island Effects. Although the matte roof tile shows a slightly higher SRI value (82) than the brilliant one (78), the results for the variables that composes the SRI value (reflectance and emittance) were very similar. Analysis of XRD, SEM and EDS performed on the surfaces of the two roofs indicated for the matte glaze the presence of microcrystals (with barium and zinc) that can contribute to the slightly highest value of SRI. The roughness (optical interferometer white light) and the brightness (brightness meter) of the samples were also measured. (author)

Patch layout generation by detecting feature networks

KAUST Repository

Cao, Yuanhao

2015-02-01

The patch layout of 3D surfaces reveals the high-level geometric and topological structures. In this paper, we study the patch layout computation by detecting and enclosing feature loops on surfaces. We present a hybrid framework which combines several key ingredients, including feature detection, feature filtering, feature curve extension, patch subdivision and boundary smoothing. Our framework is able to compute patch layouts through concave features as previous approaches, but also able to generate nice layouts through smoothing regions. We demonstrate the effectiveness of our framework by comparing with the state-of-the-art methods.

Growth of thin fullerene films by matrix assisted pulsed laser evaporation

DEFF Research Database (Denmark)

Canulescu, Stela; Schou, Jørgen; Fæster, Søren

C60 fullerene thin films of average thickness of more than 100 nm on silicon substrates can be produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was directed onto a frozen target of anisole with a concentration of 0.67 wt% C60. At laser fluences below 1.......5 J/cm2 the dominant fraction of the film molecules are C60 transferred to the substrate without any fragmentation. For high fluences high-resolution SEM images of MAPLE deposited films reveal large circular features on the surface with high amount of material concentrated at edges. These features......, observed over a wide range of laser fluences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in films...

Feature-Based Retinal Image Registration Using D-Saddle Feature

Directory of Open Access Journals (Sweden)

Roziana Ramli

2017-01-01

Full Text Available Retinal image registration is important to assist diagnosis and monitor retinal diseases, such as diabetic retinopathy and glaucoma. However, registering retinal images for various registration applications requires the detection and distribution of feature points on the low-quality region that consists of vessels of varying contrast and sizes. A recent feature detector known as Saddle detects feature points on vessels that are poorly distributed and densely positioned on strong contrast vessels. Therefore, we propose a multiresolution difference of Gaussian pyramid with Saddle detector (D-Saddle to detect feature points on the low-quality region that consists of vessels with varying contrast and sizes. D-Saddle is tested on Fundus Image Registration (FIRE Dataset that consists of 134 retinal image pairs. Experimental results show that D-Saddle successfully registered 43% of retinal image pairs with average registration accuracy of 2.329 pixels while a lower success rate is observed in other four state-of-the-art retinal image registration methods GDB-ICP (28%, Harris-PIIFD (4%, H-M (16%, and Saddle (16%. Furthermore, the registration accuracy of D-Saddle has the weakest correlation (Spearman with the intensity uniformity metric among all methods. Finally, the paired t-test shows that D-Saddle significantly improved the overall registration accuracy of the original Saddle.

Computation and Evaluation of Features of Surface Electromyogram to Identify the Force of Muscle Contraction and Muscle Fatigue

Directory of Open Access Journals (Sweden)

Sridhar P. Arjunan

2014-01-01

Full Text Available The relationship between force of muscle contraction and muscle fatigue with six different features of surface electromyogram (sEMG was determined by conducting experiments on thirty-five volunteers. The participants performed isometric contractions at 50%, 75%, and 100% of their maximum voluntary contraction (MVC. Six features were considered in this study: normalised spectral index (NSM5, median frequency, root mean square, waveform length, normalised root mean square (NRMS, and increase in synchronization (IIS index. Analysis of variance (ANOVA and linear regression analysis were performed to determine the significance of the feature with respect to the three factors: muscle force, muscle fatigue, and subject. The results show that IIS index of sEMG had the highest correlation with muscle fatigue and the relationship was statistically significant (P0.05.

Computation and evaluation of features of surface electromyogram to identify the force of muscle contraction and muscle fatigue.

Science.gov (United States)

Arjunan, Sridhar P; Kumar, Dinesh K; Naik, Ganesh

2014-01-01

The relationship between force of muscle contraction and muscle fatigue with six different features of surface electromyogram (sEMG) was determined by conducting experiments on thirty-five volunteers. The participants performed isometric contractions at 50%, 75%, and 100% of their maximum voluntary contraction (MVC). Six features were considered in this study: normalised spectral index (NSM5), median frequency, root mean square, waveform length, normalised root mean square (NRMS), and increase in synchronization (IIS) index. Analysis of variance (ANOVA) and linear regression analysis were performed to determine the significance of the feature with respect to the three factors: muscle force, muscle fatigue, and subject. The results show that IIS index of sEMG had the highest correlation with muscle fatigue and the relationship was statistically significant (P 0.05).

Ball assisted device for analytical surface sampling

Science.gov (United States)

ElNaggar, Mariam S; Van Berkel, Gary J; Covey, Thomas R

2015-11-03

A system for sampling a surface includes a sampling probe having a housing and a socket, and a rolling sampling sphere within the socket. The housing has a sampling fluid supply conduit and a sampling fluid exhaust conduit. The sampling fluid supply conduit supplies sampling fluid to the sampling sphere. The sampling fluid exhaust conduit has an inlet opening for receiving sampling fluid carried from the surface by the sampling sphere. A surface sampling probe and a method for sampling a surface are also disclosed.

UV-assisted synthesis of surface modified mesoporous TiO{sub 2}/G microspheres and its electrochemical performances in lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Tong, Xiaoling; Zeng, Min, E-mail: zengmin@swust.edu.cn; Li, Jing; Li, Fuyun

2017-01-15

Highlights: • We synthesize the surface modified mesoporous TiO{sub 2}/G microspheres, which possess high surface area with 258 m{sup 2} g{sup −1} and narrow pore size at about 7.8 nm. • The surface reaction mechanism of the UV-assisted synthesis mesoporous TiO{sub 2}/G microspheres has been explored. • The as-made TiO{sub 2}/G microspheres exhibit excellent electrochemical performances and deliver a capacity of 141 mAh g{sup −1} upon 100 cycles even at 1 C. - Abstract: Three-dimensional mesoporous TiO{sub 2}/graphene (TiO{sub 2}/G) microspheres have been successfully synthesized through a simple UV-assisted method of reduced graphene oxide with hydrazine. The as-made surface modified mesoporous TiO{sub 2}/G microspheres possess large surface area and exhibit a high initial discharge capacity of 220 mAh g{sup −1} and retain 84% (∼185 mAh g{sup −1}) of reversible capacity over 100 cycles at a rate of 0.2C. In addition, TiO{sub 2}/G microspheres display improved cyclic performance, excellent rate capability and enhanced electrical conductivity, which are superior to the bare TiO{sub 2} microspheres. Furthermore, TiO{sub 2}/G microspheres can achieve a reversible capacity of 141 mAh g{sup −1} upon 100 cycles even at the 1C rate. We believe that the mesoporous TiO{sub 2}/G microspheres are expected to be a promising high performance anode material for the next generation lithium ion batteries.

Local changes of work function near rough features on Cu surfaces operated under high external electric field

Energy Technology Data Exchange (ETDEWEB)

Djurabekova, Flyura, E-mail: flyura.djurabekova@helsinki.fi; Ruzibaev, Avaz; Parviainen, Stefan [Helsinki Institute of Physics and Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki (Finland); Holmström, Eero [Department of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki (Finland); Department of Earth Sciences, Faculty of Maths and Physical Sciences, UCL Earth Sciences, Gower Street, London WC1E 6BT (United Kingdom); Hakala, Mikko [Department of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki (Finland)

2013-12-28

Metal surfaces operated under high electric fields produce sparks even if they are held in ultra high vacuum. In spite of extensive research on the topic of vacuum arcs, the mystery of vacuum arc origin still remains unresolved. The indications that the sparking rates depend on the material motivate the research on surface response to extremely high external electric fields. In this work by means of density-functional theory calculations we analyze the redistribution of electron density on (100) Cu surfaces due to self-adatoms and in presence of high electric fields from −1 V/nm up to −2 V/nm (−1 to −2 GV/m, respectively). We also calculate the partial charge induced by the external field on a single adatom and a cluster of two adatoms in order to obtain reliable information on charge redistribution on surface atoms, which can serve as a benchmarking quantity for the assessment of the electric field effects on metal surfaces by means of molecular dynamics simulations. Furthermore, we investigate the modifications of work function around rough surface features, such as step edges and self-adatoms.

Polyethylenimine-assisted seed-mediated synthesis of gold nanoparticles for surface-enhanced Raman scattering studies

Science.gov (United States)

Philip, Anish; Ankudze, Bright; Pakkanen, Tuula T.

2018-06-01

Large-sized gold nanoparticles (AuNPs) were synthesized with a new polyethylenimine - assisted seed - mediated method for surface-enhanced Raman scattering (SERS) studies. The size and polydispersity of gold nanoparticles are controlled in the growth step with the amounts of polyethylenimine (PEI) and seeds. Influence of three silicon oxide supports having different surface morphologies, namely halloysite (Hal) nanotubes, glass plates and inverse opal films of SiO2, on the performance of gold nanoparticles in Raman scattering of a 4-aminothiophenol (4-ATP) analyte was investigated. Electrostatic interaction between positively charged polyethylenimine-capped AuNPs and negatively charged surfaces of silicon oxide supports was utilized in fabrication of the SERS substrates using deposition and infiltration methods. The Au-photonic crystal of the three SERS substrate groups is the most active one as it showed the highest analytical enhancement factor (AEF) and the lowest detection limit of 1x10-8 M for 4-ATP. Coupling of the optical properties of photonic crystals with the plasmonic properties of AuNPs provided Au-photonic crystals with the high SERS activity. The AuNPs clusters formed both in the photonic crystal and on the glass plate are capable of forming more hot spots as compared to sparsely distributed AuNPs on Hal nanotubes and thereby increasing the SERS enhancement.

Immunohistochemical features of progesterone receptors expression of placental barrier in women with multiple pregnancies resulting from assisted reproduction

Directory of Open Access Journals (Sweden)

T. D. Zadorozhna

2016-01-01

Full Text Available Hormonal disorders are one of the main known causes of miscarriage and preterm birth in multiple pregnancies resulting from assisted reproductive technology (ART. Progesterone and the number of its receptors play an important role in the preservation and prolongation of pregnancy and it is the pressing issue of our time. The study of placentas, as the main site of synthesis of progesterone, has high informative potential and it is the most important diagnostic object, and information received by its research is essential for the full conclusion on the causes, mechanisms, close and long-term effects of multiple pregnancy pathology. Aim. The aim of our study was to investigate immunohistochemical features of placentas from women with dichorionic diamniotic twin pregnancies in spontaneous fertilization and after use of assisted reproductive technology (ART. Methods and results. According to this goal we examined 94 women, 44 of whom had multiple pregnancies due to ART, 42 with separate multiple pregnancy and 38 women with a singleton pregnancy. We carried out clinical and statistical analysis of the course of pregnancy and childbirth in the studied groups. During the study it was found that multiple pregnancies due to assisted reproduction belong to the high risk of gestation, at which premature births occur much more frequently than in singleton pregnancies. We were the first to carry out the immunohistochemical study of placentas in which the highest expression of progesterone receptors in the nuclei of cells of decidua (45% related to the parent structure of the placenta from women with multiple pregnancies caused by ART is found. It is also found that with increasing gestational age, there has been a significant decrease in the expression of the activity of progesterone receptors (from 45 to 2.5%, regardless of the method of conception and the number of fetuses. Conclusions. The results of the study point to the definitive link of structures of

Experimental and Numerical Investigation of the Effect of Process Conditions on Residual Wall Thickness and Cooling and Surface Characteristics of Water-Assisted Injection Molded Hollow Products

Directory of Open Access Journals (Sweden)

Hyungpil Park

2015-01-01

Full Text Available Recently, water-assisted injection molding was employed in the automobile industry to manufacture three-dimensional hollow tube-type products with functionalities. However, process optimization is difficult in the case of water-assisted injection molding because of the various rheological interactions between the injected water and the polymer. In this study, the boiling phenomenon that occurs because of the high melt temperature when injecting water and the molding characteristics of the hollow section during the water-assisted injection process were analyzed by a water-assisted injection molding analysis. In addition, the changes in the residual wall thickness accompanying changes in the process conditions were compared with the analysis results by considering water-assisted injection molding based on gas-assisted injection molding. Furthermore, by comparing the cooling characteristics and inner wall surface qualities corresponding to the formation of the hollow section by gas and water injections, a water-assisted injection molding technique was proposed for manufacturing hollow products with functionality.

Staphylococcus cohnii--resident of hospital environment: cell-surface features and resistance to antibiotics.

Science.gov (United States)

Szewczyk, E M; Rózalska, M

2000-01-01

Staphylococcus cohnii strains dominated in the environment of investigated hospitals. We isolated 420 strains of the species mainly from hospitals environments, but also from infants--Intensive Care Units patients, its medical staff and non-hospital environments. S. cohnii subspecies cohnii was seen to dominate (361 strains). Seventy seven percent of these strains expressed cell-surface hydrofobicity, most of them were slime producers (61%) and this feature was correlated with their methicillin resistance. Among S. cohnii ssp. cohnii strains isolated from ICU environment 90% were resistant to methicillin, 43% expressed high-level resistance to mupirocin and high percentages were resistant to many other antibiotics. These strains may constitute a dangerous reservoir of resistance genes in a hospital.

Solvent-vapor-assisted imprint lithography

NARCIS (Netherlands)

Voicu, Nicoleta E.; Ludwigs, Sabine; Crossland, Edward J. W.; Andrew, Piers; Steiner, Ullrich

2007-01-01

Sub-micrometer features are replicated into high-molecular-weight polymer resists by using solvent-assisted nanoimprint lithography (see figure). By swelling the polymer in a controlled solvent-vapor atmosphere, millibar pressures and ambient temperatures are sufficient to achieve high-fidelity

EFFECTIVE DETECTION OF SUB-SURFACE ARCHEOLOGICAL FEATURES FROM LASER SCANNING POINT CLOUDS AND IMAGERY DATA

Directory of Open Access Journals (Sweden)

A. Fryskowska

2017-08-01

Full Text Available The archaeological heritage is non-renewable, and any invasive research or other actions leading to the intervention of mechanical or chemical into the ground lead to the destruction of the archaeological site in whole or in part. For this reason, modern archeology is looking for alternative methods of non-destructive and non-invasive methods of new objects identification. The concept of aerial archeology is relation between the presence of the archaeological site in the particular localization, and the phenomena that in the same place can be observed on the terrain surface form airborne platform. One of the most appreciated, moreover, extremely precise, methods of such measurements is airborne laser scanning. In research airborne laser scanning point cloud with a density of 5 points/sq. m was used. Additionally unmanned aerial vehicle imagery data was acquired. Test area is located in central Europe. The preliminary verification of potentially microstructures localization was the creation of digital terrain and surface models. These models gave an information about the differences in elevation, as well as regular shapes and sizes that can be related to the former settlement/sub-surface feature. The paper presents the results of the detection of potentially sub-surface microstructure fields in the forestry area.

Effective Detection of Sub-Surface Archeological Features from Laser Scanning Point Clouds and Imagery Data

Science.gov (United States)

Fryskowska, A.; Kedzierski, M.; Walczykowski, P.; Wierzbicki, D.; Delis, P.; Lada, A.

2017-08-01

The archaeological heritage is non-renewable, and any invasive research or other actions leading to the intervention of mechanical or chemical into the ground lead to the destruction of the archaeological site in whole or in part. For this reason, modern archeology is looking for alternative methods of non-destructive and non-invasive methods of new objects identification. The concept of aerial archeology is relation between the presence of the archaeological site in the particular localization, and the phenomena that in the same place can be observed on the terrain surface form airborne platform. One of the most appreciated, moreover, extremely precise, methods of such measurements is airborne laser scanning. In research airborne laser scanning point cloud with a density of 5 points/sq. m was used. Additionally unmanned aerial vehicle imagery data was acquired. Test area is located in central Europe. The preliminary verification of potentially microstructures localization was the creation of digital terrain and surface models. These models gave an information about the differences in elevation, as well as regular shapes and sizes that can be related to the former settlement/sub-surface feature. The paper presents the results of the detection of potentially sub-surface microstructure fields in the forestry area.

Green ultrasound-assisted extraction of anthocyanin and phenolic compounds from purple sweet potato using response surface methodology

Science.gov (United States)

Zhu, Zhenzhou; Guan, Qingyan; Guo, Ying; He, Jingren; Liu, Gang; Li, Shuyi; Barba, Francisco J.; Jaffrin, Michel Y.

2016-01-01

Response surface methodology was used to optimize experimental conditions for ultrasound-assisted extraction of valuable components (anthocyanins and phenolics) from purple sweet potatoes using water as a solvent. The Box-Behnken design was used for optimizing extraction responses of anthocyanin extraction yield, phenolic extraction yield, and specific energy consumption. Conditions to obtain maximal anthocyanin extraction yield, maximal phenolic extraction yield, and minimal specific energy consumption were different; an overall desirability function was used to search for overall optimal conditions: extraction temperature of 68ºC, ultrasonic treatment time of 52 min, and a liquid/solid ratio of 20. The optimized anthocyanin extraction yield, phenolic extraction yield, and specific energy consumption were 4.91 mg 100 g-1 fresh weight, 3.24 mg g-1 fresh weight, and 2.07 kWh g-1, respectively, with a desirability of 0.99. This study indicates that ultrasound-assisted extraction should contribute to a green process for valorization of purple sweet potatoes.

3D SEM for surface topography quantification – a case study on dental surfaces

International Nuclear Information System (INIS)

Glon, F; Flys, O; Lööf, P-J; Rosén, B-G

2014-01-01

3D analysis of surface topography is becoming a more used tool for industry and research. New ISO standards are being launched to assist in quantifying engineering surfaces. The traditional optical measuring instrumentation used for 3D surface characterization has been optical interferometers and confocal based instrumentation. However, the resolution here is limited in the lateral dimension to the wavelength of visible light to about 500 nm. The great advantage using the SEM for topography measurements is the high flexibility to zoom from low magnifications and locating interesting areas to high magnification of down to nanometer large surface features within seconds. This paper presents surface characterization of dental implant micro topography. 3D topography data was created from SEM images using commercial photogrammetric software. A coherence scanning interferometer was used for reference measurements to compare with the 3D SEM measurements on relocated areas. As a result of this study, measurements emphasizes that the correlation between the accepted CSI measurements and the new technology represented by photogrammetry based on SEM images for many areal characterization parameters are around or less than 20%. The importance of selecting sampling and parameter sensitivity to varying sampling is high-lighted. Future work includes a broader study of limitations of the photogrammetry technique on certified micro-geometries and more application surfaces at different scales

Friction characteristics of submicrometre-structured surfaces fabricated by particle-assisted near-field enhancement with femtosecond laser

International Nuclear Information System (INIS)

Sakai, Tetsuo; Nedyalkov, Nikolay; Obara, Minoru

2007-01-01

We present friction characteristics of sliding textured silicon surfaces at the submicrometre scale. A two-dimensional submicrometre dimple array on the Si surface is fabricated by femtosecond laser processing. Direct femtosecond laser nano-structuring of the Si (1 0 0) substrate by polystyrene particle-assisted near-field enhancement is used. In the investigated hole diameter domain from 229 to 548 nm, an increase in the friction coefficient with the decrease in the hole size is found experimentally. The fabricated submicrometre dimples act evidently as lubricant reservoirs to supply lubricants and traps to capture wear debris. The fluctuation of the friction coefficient is also increased by reducing the dimple size. The lowest friction coefficient of 1.41 x 10 -2 is achieved with the dimple array having a diameter of about 550 nm. This value is 2.6 times lower than that of non-structured substrates

Combining Landform Thematic Layer and Object-Oriented Image Analysis to Map the Surface Features of Mountainous Flood Plain Areas

Science.gov (United States)

Chuang, H.-K.; Lin, M.-L.; Huang, W.-C.

2012-04-01

The Typhoon Morakot on August 2009 brought more than 2,000 mm of cumulative rainfall in southern Taiwan, the extreme rainfall event caused serious damage to the Kaoping River basin. The losses were mostly blamed on the landslides along sides of the river, and shifting of the watercourse even led to the failure of roads and bridges, as well as flooding and levees damage happened around the villages on flood bank and terraces. Alluvial fans resulted from debris flow of stream feeders blocked the main watercourse and debris dam was even formed and collapsed. These disasters have highlighted the importance of identification and map the watercourse alteration, surface features of flood plain area and artificial structures soon after the catastrophic typhoon event for natural hazard mitigation. Interpretation of remote sensing images is an efficient approach to acquire spatial information for vast areas, therefore making it suitable for the differentiation of terrain and objects near the vast flood plain areas in a short term. The object-oriented image analysis program (Definiens Developer 7.0) and multi-band high resolution satellite images (QuickBird, DigitalGlobe) was utilized to interpret the flood plain features from Liouguei to Baolai of the the Kaoping River basin after Typhoon Morakot. Object-oriented image interpretation is the process of using homogenized image blocks as elements instead of pixels for different shapes, textures and the mutual relationships of adjacent elements, as well as categorized conditions and rules for semi-artificial interpretation of surface features. Digital terrain models (DTM) are also employed along with the above process to produce layers with specific "landform thematic layers". These layers are especially helpful in differentiating some confusing categories in the spectrum analysis with improved accuracy, such as landslides and riverbeds, as well as terraces, riverbanks, which are of significant engineering importance in disaster

Mixed quantum-classical equilibrium in global flux surface hopping

International Nuclear Information System (INIS)

Sifain, Andrew E.; Wang, Linjun; Prezhdo, Oleg V.

2015-01-01

Global flux surface hopping (GFSH) generalizes fewest switches surface hopping (FSSH)—one of the most popular approaches to nonadiabatic molecular dynamics—for processes exhibiting superexchange. We show that GFSH satisfies detailed balance and leads to thermodynamic equilibrium with accuracy similar to FSSH. This feature is particularly important when studying electron-vibrational relaxation and phonon-assisted transport. By studying the dynamics in a three-level quantum system coupled to a classical atom in contact with a classical bath, we demonstrate that both FSSH and GFSH achieve the Boltzmann state populations. Thermal equilibrium is attained significantly faster with GFSH, since it accurately represents the superexchange process. GFSH converges closer to the Boltzmann averages than FSSH and exhibits significantly smaller statistical errors

Reactivity of Surface Nitrates in H2-Assisted SCR of NOx Over Ag/Al2O3 Catalyst

DEFF Research Database (Denmark)

Sadokhina, N. A.; Doronkin, Dmitry E.; Baeva, G. N.

2013-01-01

The role of nitrate ad-species in H2-assisted SCR over Ag/Al2O3 was compared in NH3-SCR and n-C6H14-SCR processes. It was found that nitrates could be reduced by NH3 or n-C6H14 at similar rates with H2 co-feeding which indicates a common rate-limiting step. However, contributions of surface nitrate...... reduction to the overall NH3-SCR or n-C6H14-SCR are different as revealed by comparing the rates of nitrate reduction with the rates of steady-state processes. The rate of the steady-state n-C6H14-SCR is virtually identical to the rate of surface nitrate reduction suggesting a significant contribution...... of the surface nitrates reduction to the overall n-C6H14-SCR process. On the other hand, the steady-state rate of NH3-SCR is by ~15 times higher, which indicates that the reduction of surface nitrates plays a marginal role in the overall NH3-SCR....

Process optimization for ultrasonic vibration assisted polishing of micro-structured surfaces on super hard material

Science.gov (United States)

Sun, Zhiyuan; Guo, Bing; Rao, Zhimin; Zhao, Qingliang

2014-08-01

In consideration of the excellent property of SiC, the ground micro-structured surface quality is hard to meet the requirement - consequently the ultrasonic vibration assisted polishing (UVAP) of micro-structures of molds is proposed in this paper. Through the orthogonal experiment, the parameters of UVAP of micro-structures were optimized. The experimental results show that, abrasive polishing process, the effect of the workpiece feed rate on the surface roughness (Ra), groove tip radius (R) and material removal rate (MRR) of micro-structures is significant. While, the UVAP, the most significant effect factor for Ra, R and MRR is the ultrasonic amplitude of the ultrasonic vibration. In addition, within the scope of the polishing process parameters selected by preliminary experiments, ultrasonic amplitude of 2.5μm, polishing force of 0.5N, workpiece feed rate of 5 mm·min-1, polishing wheel rotational speed of 50rpm, polishing time of 35min, abrasive size of 100nm and the polishing liquid concentration of 15% is the best technology of UVAP of micro-structures. Under the optimal parameters, the ground traces on the micro-structured surface were removed efficiently and the integrity of the edges of the micro-structure after grinding was maintained efficiently.

Prostate cancer detection: Fusion of cytological and textural features.

Science.gov (United States)

Nguyen, Kien; Jain, Anil K; Sabata, Bikash

2011-01-01

A computer-assisted system for histological prostate cancer diagnosis can assist pathologists in two stages: (i) to locate cancer regions in a large digitized tissue biopsy, and (ii) to assign Gleason grades to the regions detected in stage 1. Most previous studies on this topic have primarily addressed the second stage by classifying the preselected tissue regions. In this paper, we address the first stage by presenting a cancer detection approach for the whole slide tissue image. We propose a novel method to extract a cytological feature, namely the presence of cancer nuclei (nuclei with prominent nucleoli) in the tissue, and apply this feature to detect the cancer regions. Additionally, conventional image texture features which have been widely used in the literature are also considered. The performance comparison among the proposed cytological textural feature combination method, the texture-based method and the cytological feature-based method demonstrates the robustness of the extracted cytological feature. At a false positive rate of 6%, the proposed method is able to achieve a sensitivity of 78% on a dataset including six training images (each of which has approximately 4,000×7,000 pixels) and 1 1 whole-slide test images (each of which has approximately 5,000×23,000 pixels). All images are at 20X magnification.

Nonmotor Features in Atypical Parkinsonism.

Science.gov (United States)

Bhatia, Kailash P; Stamelou, Maria

2017-01-01

Atypical parkinsonism (AP) comprises mainly multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), which are distinct pathological entities, presenting with a wide phenotypic spectrum. The classic syndromes are now called MSA-parkinsonism (MSA-P), MSA-cerebellar type (MSA-C), Richardson's syndrome, and corticobasal syndrome. Nonmotor features in AP have been recognized almost since the initial description of these disorders; however, research has been limited. Autonomic dysfunction is the most prominent nonmotor feature of MSA, but also gastrointestinal symptoms, sleep dysfunction, and pain, can be a feature. In PSP and CBD, the most prominent nonmotor symptoms comprise those deriving from the cognitive/neuropsychiatric domain. Apart from assisting the clinician in the differential diagnosis with Parkinson's disease, nonmotor features in AP have a big impact on quality of life and prognosis of AP and their treatment poses a major challenge for clinicians. © 2017 Elsevier Inc. All rights reserved.

An algorithm for analytical solution of basic problems featuring elastostatic bodies with cavities and surface flaws

Science.gov (United States)

Penkov, V. B.; Levina, L. V.; Novikova, O. S.; Shulmin, A. S.

2018-03-01

Herein we propose a methodology for structuring a full parametric analytical solution to problems featuring elastostatic media based on state-of-the-art computing facilities that support computerized algebra. The methodology includes: direct and reverse application of P-Theorem; methods of accounting for physical properties of media; accounting for variable geometrical parameters of bodies, parameters of boundary states, independent parameters of volume forces, and remote stress factors. An efficient tool to address the task is the sustainable method of boundary states originally designed for the purposes of computerized algebra and based on the isomorphism of Hilbertian spaces of internal states and boundary states of bodies. We performed full parametric solutions of basic problems featuring a ball with a nonconcentric spherical cavity, a ball with a near-surface flaw, and an unlimited medium with two spherical cavities.

Contributions of feature shapes and surface cues to the recognition and neural representation of facial identity.

Science.gov (United States)

Andrews, Timothy J; Baseler, Heidi; Jenkins, Rob; Burton, A Mike; Young, Andrew W

2016-10-01

A full understanding of face recognition will involve identifying the visual information that is used to discriminate different identities and how this is represented in the brain. The aim of this study was to explore the importance of shape and surface properties in the recognition and neural representation of familiar faces. We used image morphing techniques to generate hybrid faces that mixed shape properties (more specifically, second order spatial configural information as defined by feature positions in the 2D-image) from one identity and surface properties from a different identity. Behavioural responses showed that recognition and matching of these hybrid faces was primarily based on their surface properties. These behavioural findings contrasted with neural responses recorded using a block design fMRI adaptation paradigm to test the sensitivity of Haxby et al.'s (2000) core face-selective regions in the human brain to the shape or surface properties of the face. The fusiform face area (FFA) and occipital face area (OFA) showed a lower response (adaptation) to repeated images of the same face (same shape, same surface) compared to different faces (different shapes, different surfaces). From the behavioural data indicating the critical contribution of surface properties to the recognition of identity, we predicted that brain regions responsible for familiar face recognition should continue to adapt to faces that vary in shape but not surface properties, but show a release from adaptation to faces that vary in surface properties but not shape. However, we found that the FFA and OFA showed an equivalent release from adaptation to changes in both shape and surface properties. The dissociation between the neural and perceptual responses suggests that, although they may play a role in the process, these core face regions are not solely responsible for the recognition of facial identity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Disorder-driven metal-insulator-transition assisted by interband Coulomb repulsion in a surface transfer doped electron system

Science.gov (United States)

Francisco Sánchez-Royo, Juan

2012-12-01

The two-dimensional conducting properties of the Si(111) \\sqrt {3} \\times \\sqrt {3} surface doped by the charge surface transfer mechanism have been calculated in the frame of a semiclassical Drude-Boltzmann model considering donor scattering mechanisms. To perform these calculations, the required values of the carrier effective mass were extracted from reported angle-resolved photoemission results. The calculated doping dependence of the surface conductance reproduces experimental results reported and reveals an intricate metallization process driven by disorder and assisted by interband interactions. The system should behave as an insulator even at relatively low doping due to disorder. However, when doping increases, the system achieves to attenuate the inherent localization effects introduced by disorder and to conduct by percolation. The mechanism found by the system to conduct appears to be connected with the increasing of the carrier effective mass observed with doping, which seems to be caused by interband interactions involving the conducting band and deeper ones. This mass enhancement reduces the donor Bohr radius and, consequently, promotes the screening ability of the donor potential by the electron gas.

Assistance Focus: Africa

Energy Technology Data Exchange (ETDEWEB)

2017-03-29

The Clean Energy Solutions Center, an initiative of the Clean Energy Ministerial, helps countries throughout the world create policies and programs that advance the deployment of clean energy technologies. Through the Solutions Center's no-cost 'Ask an Expert' service, a team of international experts has delivered assistance to countries in all regions of the world. High-impact examples from Africa are featured here.

Optimizing the conditions for the microwave-assisted direct liquefaction of Ulva prolifera for bio-oil production using response surface methodology

International Nuclear Information System (INIS)

Liu, Junhai; Zhuang, Yingbin; Li, Yan; Chen, Limei; Guo, Jingxue; Li, Demao; Ye, Naihao

2013-01-01

Microwave-assisted direct liquefaction (MADL) of Ulva prolifera was performed in ethylene glycol (EG) using sulfuric acid (H 2 SO 4 ) as a catalyst. Response Surface Methodology (RSM) based on central composite rotatable design (CCRD) was employed to optimize the conditions of three independent variables (catalyst content, solvent-to-feedstock ratio and temperature) for the liquefaction yield. And the bio-oil was analyzed by elementary analysis, Fourier transform infrared spectroscopic analysis (FT-IR) and gas chromatography–mass spectrometry (GC–MS). The maximum liquefaction yield was 93.17%, which was obtained under a microwave power of 600 W for 30 min at 165 °C with a solvent-to-feedstock ratio of 18.87:1 and 4.93% sulfuric acid. The bio-oil was mainly composed of phthalic acid esters, alkenes and a fatty acid methyl ester with a long chain from C 16 to C 20 . - Highlights: • Ulva prolifera was converted to bio-oil through microwave-assisted direct liquefaction. • Response surface methodology was used to optimize the liquefaction technology. • A maximum liquefaction rate of 93.17 wt% bio-oil was obtained. • The bio-oil was composed of carboxylic acids and esters

A study of the flow boiling heat transfer in a minichannel for a heated wall with surface texture produced by vibration-assisted laser machining

International Nuclear Information System (INIS)

Piasecka, Magdalena; Strąk, Kinga; Grabas, Bogusław; Maciejewska, Beata

2016-01-01

The paper presents results concerning flow boiling heat transfer in a vertical minichannel with a depth of 1.7 mm and a width of 16 mm. The element responsible for heating FC-72, which flowed laminarly in the minichannel, was a plate with an enhanced surface. Two types of surface textures were considered. Both were produced by vibration-assisted laser machining. Infrared thermography was used to record changes in the temperature on the outer smooth side of the plate. Two-phase flow patterns were observed through a glass pane. The main aim of the study was to analyze how the two types of surface textures affect the heat transfer coefficient. A two-dimensional heat transfer approach was proposed to determine the local values of the heat transfer coefficient. The inverse problem for the heated wall was solved using a semi-analytical method based on the Trefftz functions. The results are presented as relationships between the heat transfer coefficient and the distance along the minichannel length and as boiling curves. The experimental data obtained for the two types of enhanced heated surfaces was compared with the results recorded for the smooth heated surface. The highest local values of the heat transfer coefficient were reported in the saturated boiling region for the plate with the type 1 texture produced by vibration-assisted laser machining. (paper)

Response Surface Methodology for Biodiesel Production Using Calcium Methoxide Catalyst Assisted with Tetrahydrofuran as Cosolvent

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Nichaonn Chumuang

2017-01-01

Full Text Available The present study was performed to optimize a heterogeneous calcium methoxide (Ca(OCH32 catalyzed transesterification process assisted with tetrahydrofuran (THF as a cosolvent for biodiesel production from waste cooking oil. Response surface methodology (RSM with a 5-level-4-factor central composite design was applied to investigate the effect of experimental factors on the percentage of fatty acid methyl ester (FAME conversion. A quadratic model with an analysis of variance obtained from the RSM is suggested for the prediction of FAME conversion and reveals that 99.43% of the observed variation is explained by the model. The optimum conditions obtained from the RSM were 2.83 wt% of catalyst concentration, 11.6 : 1 methanol-to-oil molar ratio, 100.14 min of reaction time, and 8.65% v/v of THF in methanol concentration. Under these conditions, the properties of the produced biodiesel satisfied the standard requirement. THF as cosolvent successfully decreased the catalyst concentration, methanol-to-oil molar ratio, and reaction time when compared with biodiesel production without cosolvent. The results are encouraging for the application of Ca(OCH32 assisted with THF as a cosolvent for environmentally friendly and sustainable biodiesel production.

Home Features and Assistive Technology for the Home-Bound Elderly in a Thai Suburban Community by Applying the International Classification of Functioning, Disability, and Health

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Supawadee Putthinoi

2017-01-01

Full Text Available The ageing population is having an impact worldwide and has created a serious challenge in Thailand’s healthcare systems, whereby healthcare practitioners play a major role in promoting independent interaction of their client’s abilities, as well as environmental factors. The purpose of this study was to survey features of the home and assistive technology (AT for the home-bound elderly in the community of Chiang Mai, Thailand. Home evaluation included features inside and outside the home, and AT was based on the International Classification of Functioning, Disability, and Health (ICF concept. Methods included observation and an interview that were used by the researcher for evaluation. The study found that every home had at least one hazardous home feature such as inappropriate width of the door, high door threshold, tall stair steps, no bedside rail, and inappropriate height of the toilet pan. AT was found in houses as general products and technology for personal use in daily living and for personal indoor and outdoor mobility as well as transportation. Therefore, home features and AT can afford the home-bound elderly independent living within the community. Perspective AT according to the ICF concept could provide a common language for ageing in place benefits.

SdrF, a Staphylococcus epidermidis surface protein, contributes to the initiation of ventricular assist device driveline-related infections.

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Carlos Arrecubieta

2009-05-01

Full Text Available Staphylococcus epidermidis remains the predominant pathogen in prosthetic-device infections. Ventricular assist devices, a recently developed form of therapy for end-stage congestive heart failure, have had considerable success. However, infections, most often caused by Staphylococcus epidermidis, have limited their long-term use. The transcutaneous driveline entry site acts as a potential portal of entry for bacteria, allowing development of either localized or systemic infections. A novel in vitro binding assay using explanted drivelines obtained from patients undergoing transplantation and a heterologous lactococcal system of surface protein expression were used to identify S. epidermidis surface components involved in the pathogenesis of driveline infections. Of the four components tested, SdrF, SdrG, PIA, and GehD, SdrF was identified as the primary ligand. SdrF adherence was mediated via its B domain attaching to host collagen deposited on the surface of the driveline. Antibodies directed against SdrF reduced adherence of S. epidermidis to the drivelines. SdrF was also found to adhere with high affinity to Dacron, the hydrophobic polymeric outer surface of drivelines. Solid phase binding assays showed that SdrF was also able to adhere to other hydrophobic artificial materials such as polystyrene. A murine model of infection was developed and used to test the role of SdrF during in vivo driveline infection. SdrF alone was able to mediate bacterial adherence to implanted drivelines. Anti-SdrF antibodies reduced S. epidermidis colonization of implanted drivelines. SdrF appears to play a key role in the initiation of ventricular assist device driveline infections caused by S. epidermidis. This pluripotential adherence capacity provides a potential pathway to infection with SdrF-positive commensal staphylococci first adhering to the external Dacron-coated driveline at the transcutaneous entry site, then spreading along the collagen

The Distinction Between Curative and Assistive Technology.

Science.gov (United States)

Stramondo, Joseph A

2018-05-01

Disability activists have sometimes claimed their disability has actually increased their well-being. Some even say they would reject a cure to keep these gains. Yet, these same activists often simultaneously propose improvements to the quality and accessibility of assistive technology. However, for any argument favoring assistive over curative technology (or vice versa) to work, there must be a coherent distinction between the two. This line is already vague and will become even less clear with the emergence of novel technologies. This paper asks and tries to answer the question: what is it about the paradigmatic examples of curative and assistive technologies that make them paradigmatic and how can these defining features help us clarify the hard cases? This analysis will begin with an argument that, while the common views of this distinction adequately explain the paradigmatic cases, they fail to accurately pick out the relevant features of those technologies that make them paradigmatic and to provide adequate guidance for parsing the hard cases. Instead, it will be claimed that these categories of curative or assistive technologies are defined by the role the technologies play in establishing a person's relational narrative identity as a member of one of two social groups: disabled people or non-disabled people.

Left ventricular assist device (lvad design features: literature review

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Yu. V. Bogdanova

2014-01-01

Full Text Available More than 8 million people in our country suffer from heart failure. About one million of these people die each year [1]. The problem of ventricular assist device creating - a mechanical device used for partial or complete replacement of heart function - is investigated for a long time (according to [2] just in our country since the 1970s. Today plenty of encouraging results are received. There is a number of VAD models which are successfully applied to patients with heart failure. After implantation, patients conduct a way of life that is normal in many respects: they are in the family, often they have an opportunity to work in their former specialty. Some of them live with the device about 8 years [3].According to [4] for 2010 the estimated total number of long-term devices implanted in the United States per year is over 1,700 (the population of the U.S. is 305 million, compared with over 430 per year in Europe (the population of Europe is 731 million. Unfortunately, people who need a heart transplant are much more.The principle of VAD is that being connected to the left ventricle with one cannula and to the ascending aorta with the other cannula the pump fully or partially replaces the function of the natural heart. This scheme allows the use of VAD in two ways: as a "bridge to transplantation" when the device is used temporarily until the donor heart is found, and a "bridge to recovery", when through the use of VAD the function of the heart muscle is recovered.VAD system can be divided into three subsystems: blood pump, power supply system and control system (Fig. 1.Each subsystem can be the subject of separate study. Special role in the development of VAD plays medical side of the issue. Successful research and development require interaction with qualified professionals in this field. The development of VAD is a multidisciplinary problem which demands fulfilment of a number of requirements.One of the most active programs in implantation of

Surface-expressed enolases of Plasmodium and other pathogens

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Anil Kumar Ghosh

2011-08-01

Full Text Available Enolase is the eighth enzyme in the glycolytic pathway, a reaction that generates ATP from phosphoenol pyruvate in cytosolic compartments. Enolase is essential, especially for organisms devoid of the Krebs cycle that depend solely on glycolysis for energy. Interestingly, enolase appears to serve a separate function in some organisms, in that it is also exported to the cell surface via a poorly understood mechanism. In these organisms, surface enolase assists in the invasion of their host cells by binding plasminogen, an abundant plasma protease precursor. Binding is mediated by the interaction between a lysine motif of enolase with Kringle domains of plasminogen. The bound plasminogen is then cleaved by specific proteases to generate active plasmin. Plasmin is a potent serine protease that is thought to function in the degradation of the extracellular matrix surrounding the targeted host cell, thereby facilitating pathogen invasion. Recent work revealed that the malaria parasite Plasmodium also expresses surface enolase, and that this feature may be essential for completion of its life cycle. The therapeutic potential of targeting surface enolases of pathogens is discussed.

Prostate cancer detection: Fusion of cytological and textural features

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Kien Nguyen

2011-01-01

Full Text Available A computer-assisted system for histological prostate cancer diagnosis can assist pathologists in two stages: (i to locate cancer regions in a large digitized tissue biopsy, and (ii to assign Gleason grades to the regions detected in stage 1. Most previous studies on this topic have primarily addressed the second stage by classifying the preselected tissue regions. In this paper, we address the first stage by presenting a cancer detection approach for the whole slide tissue image. We propose a novel method to extract a cytological feature, namely the presence of cancer nuclei (nuclei with prominent nucleoli in the tissue, and apply this feature to detect the cancer regions. Additionally, conventional image texture features which have been widely used in the literature are also considered. The performance comparison among the proposed cytological textural feature combination method, the texture-based method and the cytological feature-based method demonstrates the robustness of the extracted cytological feature. At a false positive rate of 6%, the proposed method is able to achieve a sensitivity of 78% on a dataset including six training images (each of which has approximately 4,000x7,000 pixels and 1 1 whole-slide test images (each of which has approximately 5,000x23,000 pixels. All images are at 20X magnification.

Metal-oxide assisted surface treatment of polyimide gate insulators for high-performance organic thin-film transistors.

Science.gov (United States)

Kim, Sohee; Ha, Taewook; Yoo, Sungmi; Ka, Jae-Won; Kim, Jinsoo; Won, Jong Chan; Choi, Dong Hoon; Jang, Kwang-Suk; Kim, Yun Ho

2017-06-14

We developed a facile method for treating polyimide-based organic gate insulator (OGI) surfaces with self-assembled monolayers (SAMs) by introducing metal-oxide interlayers, called the metal-oxide assisted SAM treatment (MAST). To create sites for surface modification with SAM materials on polyimide-based OGI (KPI) surfaces, the metal-oxide interlayer, here amorphous alumina (α-Al 2 O 3 ), was deposited on the KPI gate insulator using spin-coating via a rapid sol-gel reaction, providing an excellent template for the formation of a high-quality SAM with phosphonic acid anchor groups. The SAM of octadecylphosphonic acid (ODPA) was successfully treated by spin-coating onto the α-Al 2 O 3 -deposited KPI film. After the surface treatment by ODPA/α-Al 2 O 3 , the surface energy of the KPI thin film was remarkably decreased and the molecular compatibility of the film with an organic semiconductor (OSC), 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-C 10 ), was increased. Ph-BTBT-C 10 molecules were uniformly deposited on the treated gate insulator surface and grown with high crystallinity, as confirmed by atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis. The mobility of Ph-BTBT-C 10 thin-film transistors (TFTs) was approximately doubled, from 0.56 ± 0.05 cm 2 V -1 s -1 to 1.26 ± 0.06 cm 2 V -1 s -1 , after the surface treatment. The surface treatment of α-Al 2 O 3 and ODPA significantly decreased the threshold voltage from -21.2 V to -8.3 V by reducing the trap sites in the OGI and improving the interfacial properties with the OSC. We suggest that the MAST method for OGIs can be applied to various OGI materials lacking reactive sites using SAMs. It may provide a new platform for the surface treatment of OGIs, similar to that of conventional SiO 2 gate insulators.

Mining for diagnostic information in body surface potential maps: A comparison of feature selection techniques

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McCullagh Paul J

2005-09-01

Full Text Available Abstract Background In body surface potential mapping, increased spatial sampling is used to allow more accurate detection of a cardiac abnormality. Although diagnostically superior to more conventional electrocardiographic techniques, the perceived complexity of the Body Surface Potential Map (BSPM acquisition process has prohibited its acceptance in clinical practice. For this reason there is an interest in striking a compromise between the minimum number of electrocardiographic recording sites required to sample the maximum electrocardiographic information. Methods In the current study, several techniques widely used in the domains of data mining and knowledge discovery have been employed to mine for diagnostic information in 192 lead BSPMs. In particular, the Single Variable Classifier (SVC based filter and Sequential Forward Selection (SFS based wrapper approaches to feature selection have been implemented and evaluated. Using a set of recordings from 116 subjects, the diagnostic ability of subsets of 3, 6, 9, 12, 24 and 32 electrocardiographic recording sites have been evaluated based on their ability to correctly asses the presence or absence of Myocardial Infarction (MI. Results It was observed that the wrapper approach, using sequential forward selection and a 5 nearest neighbour classifier, was capable of choosing a set of 24 recording sites that could correctly classify 82.8% of BSPMs. Although the filter method performed slightly less favourably, the performance was comparable with a classification accuracy of 79.3%. In addition, experiments were conducted to show how (a features chosen using the wrapper approach were specific to the classifier used in the selection model, and (b lead subsets chosen were not necessarily unique. Conclusion It was concluded that both the filter and wrapper approaches adopted were suitable for guiding the choice of recording sites useful for determining the presence of MI. It should be noted however

Thermal measurements of dark and bright surface features on Vesta as derived from Dawn/VIR

Science.gov (United States)

Tosi, Federico; Capria, Maria Teresa; De Sanctis, M.C.; Combe, J.-Ph.; Zambon, F.; Nathues, A.; Schröder, S.E.; Li, J.-Y.; Palomba, E.; Longobardo, A.; Blewett, D.T.; Denevi, B.W.; Palmer, E.; Capaccioni, F.; Ammannito, E.; Titus, Timothy N.; Mittlefehldt, D.W.; Sunshine, J.M.; Russell, C.T.; Raymond, C.A.; Dawn/VIR Team,

2014-01-01

Remote sensing data acquired during Dawn’s orbital mission at Vesta showed several local concentrations of high-albedo (bright) and low-albedo (dark) material units, in addition to spectrally distinct meteorite impact ejecta. The thermal behavior of such areas seen at local scale (1-10 km) is related to physical properties that can provide information about the origin of those materials. We use Dawn’s Visible and InfraRed (VIR) mapping spectrometer hyperspectral data to retrieve surface temperatures and emissivities, with high accuracy as long as temperatures are greater than 220 K. Some of the dark and bright features were observed multiple times by VIR in the various mission phases at variable spatial resolution, illumination and observation angles, local solar time, and heliocentric distance. This work presents the first temperature maps and spectral emissivities of several kilometer-scale dark and bright material units on Vesta. Results retrieved from the infrared data acquired by VIR show that bright regions generally correspond to regions with lower temperature, while dark regions correspond to areas with higher temperature. During maximum daily insolation and in the range of heliocentric distances explored by Dawn, i.e. 2.23-2.54 AU, the warmest dark unit found on Vesta rises to a temperature of 273 K, while bright units observed under comparable conditions do not exceed 266 K. Similarly, dark units appear to have higher emissivity on average compared to bright units. Dark-material units show a weak anticorrelation between temperature and albedo, whereas the relation is stronger for bright material units observed under the same conditions. Individual features may show either evanescent or distinct margins in the thermal images, as a consequence of the cohesion of the surface material. Finally, for the two categories of dark and bright materials, we were able to highlight the influence of heliocentric distance on surface temperatures, and estimate an

Synthesis of Graphite Oxide with Different Surface Oxygen Contents Assisted Microwave Radiation

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Adriana Ibarra-Hernández

2018-02-01

Full Text Available Graphite oxide is synthesized via oxidation reaction using oxidant compounds that have lattice defects by the incorporation of unlike functional groups. Herein, we report the synthesis of the graphite oxide with diverse surface oxygen content through three (B, C, D different modified versions of the Hummers method assisted microwave radiation compared with the conventional graphite oxide sample obtained by Hummers method (A. These methods allow not only the production of graphite oxide but also reduced graphene oxide, without undergoing chemical, thermal, or mechanical reduction steps. The values obtained of C/O ratio were ~2, 3.4, and ~8.5 for methodologies C, B, and D, respectively, indicating the presence of graphite oxide and reduced graphene oxide, according to X-ray photoelectron spectroscopy. Raman spectroscopy of method D shows the fewest structural defects compared to the other methodologies. The results obtained suggest that the permanganate ion produces reducing species during graphite oxidation. The generation of these species is attributed to a reversible reaction between the permanganate ion with π electrons, ions, and radicals produced after treatment with microwave radiation.

Cortical surface registration using spherical thin-plate spline with sulcal lines and mean curvature as features.

Science.gov (United States)

Park, Hyunjin; Park, Jun-Sung; Seong, Joon-Kyung; Na, Duk L; Lee, Jong-Min

2012-04-30

Analysis of cortical patterns requires accurate cortical surface registration. Many researchers map the cortical surface onto a unit sphere and perform registration of two images defined on the unit sphere. Here we have developed a novel registration framework for the cortical surface based on spherical thin-plate splines. Small-scale composition of spherical thin-plate splines was used as the geometric interpolant to avoid folding in the geometric transform. Using an automatic algorithm based on anisotropic skeletons, we extracted seven sulcal lines, which we then incorporated as landmark information. Mean curvature was chosen as an additional feature for matching between spherical maps. We employed a two-term cost function to encourage matching of both sulcal lines and the mean curvature between the spherical maps. Application of our registration framework to fifty pairwise registrations of T1-weighted MRI scans resulted in improved registration accuracy, which was computed from sulcal lines. Our registration approach was tested as an additional procedure to improve an existing surface registration algorithm. Our registration framework maintained an accurate registration over the sulcal lines while significantly increasing the cross-correlation of mean curvature between the spherical maps being registered. Copyright © 2012 Elsevier B.V. All rights reserved.

Sb(III)-Imprinted Organic-Inorganic Hybrid Sorbent Prepared by Hydrothermal-Assisted Surface Imprinting Technique for Selective Adsorption of Sb(III)

Science.gov (United States)

Zhang, Dan; Zhao, Yue; Xu, Hong-Bo

2018-03-01

Sb(III)-imprinted organic-inorganic hybrid sorbent was prepared by hydrothermal-assisted surface imprinting technique and was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy coupled to an energy dispersive spectrometer and N2 adsorption/desorption isotherms. Hydrothermal-assisted process can improve the selectivity of the Sb(III)-imprinted hybrid sorbent for Sb(III) due to stable control of temperature and pressure. The Sb(III)-imprinted hybrid sorbent IIS indicated higher selectivity for Sb(III), had high static adsorption capacity of 37.3 mg g-1 for Sb(III), displayed stable adsorption capacity in pH range from 4 to 8, reached an rapid adsorption equilibrium within 30 min. According to the correlation coefficient ( r 2 > 0.99), the experimental data fitted better the pseudo-second-order kinetic model and Langmuir equilibrium isotherm.

Matrix Assisted Pulsed Laser Evaporation for growth of fullerene thin films

DEFF Research Database (Denmark)

Canulescu, Stela; Schou, Jørgen; Fæster Nielsen, Søren

C60 fullerene thin films of average thickness of more than 100 nm can be produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was directed onto a frozen target of anisole with a concentration of 0.67 wt% C60. At laser fluences below 1.5 J/cm2, a dominant...... fraction of the film molecules are C60 transferred to the substrate without any fragmentation. Highresolution SEM images of MAPLE deposited films reveal large circular droplets on the surface with high amount of material concentrated at edges (Fig. 1A). These features, observed over a wide range of laser...... fluences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in production of films with smooth surfaces and minimal...

Proust: A Nano Proof Assistant

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Prabhakar Ragde

2016-11-01

Full Text Available Proust is a small Racket program offering rudimentary interactive assistance in the development of verified proofs for propositional and predicate logic. It is constructed in stages, some of which are done by students before using it to complete proof exercises, and in parallel with the study of its theoretical underpinnings, including elements of Martin-Lof type theory. The goal is twofold: to demystify some of the machinery behind full-featured proof assistants such as Coq and Agda, and to better integrate the study of formal logic with other core elements of an undergraduate computer science curriculum.

Optimization of microwave-assisted extraction (MAP) for ginseng components by response surface methodology.

Science.gov (United States)

Kwon, Joong-Ho; Bélanger, Jacqueline M R; Paré, J R Jocelyn

2003-03-26

Response surface methodology (RSM) was applied to predict optimum conditions for microwave-assisted extraction-a MAP technology-of saponin components from ginseng roots. A central composite design was used to monitor the effect of ethanol concentration (30-90%, X(1)) and extraction time (30-270 s, X(2)) on dependent variables, such as total extract yield (Y(1)), crude saponin content (Y(2)), and saponin ratio (Y(3)), under atmospheric pressure conditions when focused microwaves were applied at an emission frequency of 2450 MHz. In MAP under pre-established conditions, correlation coefficients (R (2)) of the models for total extract yield and crude saponin were 0.9841 (p extraction conditions were predicted for each variable as 52.6% ethanol and 224.7 s in extract yield and as 77.3% ethanol and 295.1 s in crude saponins, respectively. Estimated maximum values at predicted optimum conditions were in good agreement with experimental values.

Development of a dielectrophoresis-assisted surface plasmon resonance fluorescence biosensor for detection of bacteria

Science.gov (United States)

Kuroda, Chiaki; Iizuka, Ryota; Ohki, Yoshimichi; Fujimaki, Makoto

2018-05-01

To detect biological substances such as bacteria speedily and accurately, a dielectrophoresis-assisted surface plasmon resonance (SPR) fluorescence biosensor is being developed. Using Escherichia coli as a target organism, an appropriate voltage frequency to collect E. coli cells on indium tin oxide quadrupole electrodes by dielectrophoresis is analyzed. Then, E. coli is stained with 4‧,6-diamidino-2-phenylindole (DAPI). To clearly detect fluorescence signals from DAPI-stained E. coli cells, the sensor is optimized so that we can excite SPR on Al electrodes by illuminating 405 nm photons. As a result, the number of fluorescence signals is increased on the electrodes by the application of a low-frequency voltage. This indicates that E. coli cells with a lower permittivity than the surrounding water are collected by negative dielectrophoresis onto the electrodes where the electric field strength is lowest.

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors.

Science.gov (United States)

Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant

2010-10-21

Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG) can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI) devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS), Mean absolute value (MAV), Variance (VAR) and Waveform length (WL) and the proposed fractal features: fractal dimension (FD) and maximum fractal length (MFL) were computed. Multi-variant analysis of variance (MANOVA) was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN) classifier to decode the desired subtle movements. The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination of other features ranged between 58% and 73

Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors

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Kumar Dinesh

2010-10-01

Full Text Available Abstract Background Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. Methods SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS, Mean absolute value (MAV, Variance (VAR and Waveform length (WL and the proposed fractal features: fractal dimension (FD and maximum fractal length (MFL were computed. Multi-variant analysis of variance (MANOVA was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN classifier to decode the desired subtle movements. Results The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination

Ultrasound-assisted xanthation of cellulose from lignocellulosic biomass optimized by response surface methodology for Pb(II) sorption.

Science.gov (United States)

Wang, Chongqing; Wang, Hui; Gu, Guohua

2018-02-15

Alkali treatment of lignocellulosic biomass is conducted to remove hemi-cellulose and lignin, further increasing the reactivity and accessibility of cellulose. Ultrasound-assisted xanthation of alkali cellulose is optimized by response surface methodology (RSM) with a Box-Behnken design. A predicting mathematical model is obtained by fitting experimental data, and it is verified by analysis of variance. Response surface plots and the contour plots obtained from the model are applied to determine the interactions of experimental variables. The optimum conditions are NaOH concentration 1.3mol/L, ultrasonic time 71.6min and CS 2 dosage 1.5mL. FTIR, SEM and XPS characterizations confirm the synthesis and sorption mechanism of cellulose xanthate (CX). Biosorption of Pb (II) onto CX obeys pseudo-second order model and Langmuir model. The sorption mechanism is attributed to surface complexation or ion exchange. CX shows good reusability for Pb (II) sorption. The maximum sorption capacity of Pb(II) is 134.41mg/g, higher than that of other biosorbents. CX has great potential as an efficient and low-cost biosorbent for wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of feature extraction analysis for a multi-functional optical profiling device applied to field engineering applications

Science.gov (United States)

Han, Xu; Xie, Guangping; Laflen, Brandon; Jia, Ming; Song, Guiju; Harding, Kevin G.

2015-05-01

In the real application environment of field engineering, a large variety of metrology tools are required by the technician to inspect part profile features. However, some of these tools are burdensome and only address a sole application or measurement. In other cases, standard tools lack the capability of accessing irregular profile features. Customers of field engineering want the next generation metrology devices to have the ability to replace the many current tools with one single device. This paper will describe a method based on the ring optical gage concept to the measurement of numerous kinds of profile features useful for the field technician. The ring optical system is composed of a collimated laser, a conical mirror and a CCD camera. To be useful for a wide range of applications, the ring optical system requires profile feature extraction algorithms and data manipulation directed toward real world applications in field operation. The paper will discuss such practical applications as measuring the non-ideal round hole with both off-centered and oblique axes. The algorithms needed to analyze other features such as measuring the width of gaps, radius of transition fillets, fall of step surfaces, and surface parallelism will also be discussed in this paper. With the assistance of image processing and geometric algorithms, these features can be extracted with a reasonable performance. Tailoring the feature extraction analysis to this specific gage offers the potential for a wider application base beyond simple inner diameter measurements. The paper will present experimental results that are compared with standard gages to prove the performance and feasibility of the analysis in real world field engineering. Potential accuracy improvement methods, a new dual ring design and future work will be discussed at the end of this paper.

Computational fluid dynamics analysis of a maglev centrifugal left ventricular assist device.

Science.gov (United States)

Burgreen, Greg W; Loree, Howard M; Bourque, Kevin; Dague, Charles; Poirier, Victor L; Farrar, David; Hampton, Edward; Wu, Z Jon; Gempp, Thomas M; Schöb, Reto

2004-10-01

The fluid dynamics of the Thoratec HeartMate III (Thoratec Corp., Pleasanton, CA, U.S.A.) left ventricular assist device are analyzed over a range of physiological operating conditions. The HeartMate III is a centrifugal flow pump with a magnetically suspended rotor. The complete pump was analyzed using computational fluid dynamics (CFD) analysis and experimental particle imaging flow visualization (PIFV). A comparison of CFD predictions to experimental imaging shows good agreement. Both CFD and experimental PIFV confirmed well-behaved flow fields in the main components of the HeartMate III pump: inlet, volute, and outlet. The HeartMate III is shown to exhibit clean flow features and good surface washing across its entire operating range.

Ultrasonic-assisted preparation of graphene oxide carboxylic acid polyvinyl alcohol polymer film and studies of thermal stability and surface resistivity.

Science.gov (United States)

Li, Yongshen; Li, Jihui; Li, Yuehai; Li, Yali; Song, Yunan; Niu, Shuai; Li, Ning

2018-01-01

In this paper, flake graphite, nitric acid and acetic anhydride are used to prepare graphene oxide carboxylic acid (GO-COOH) via an ultrasonic-assisted method, and GO-COOH and polyvinyl alcohol polymer (PVA) are used to synthesize graphene oxide carboxylic acid polyvinyl alcohol polymer (GO-COOPVA) via the ultrasonic-assisted method, and GO-COOPVA is used to manufacture graphene oxide carboxylic acid polyvinyl alcohol polymer film (GO-COOPVA film) via a solidification method, and the structure and morphology of GO-COOH, GO-COOPVA and GO-COOPVA film are characterized, and the thermal stability and surface resistivity are measured in the case of the different amount of GO-COOH. Based on the characterization and measurement, it has been successively confirmed and attested that carboxyl groups implant on 2D lattice of GO to form GO-COOH, and GO-COOH and PVA have the esterification reaction to produce GO-COOPVA, and GO-COOPVA consists of 2D lattice of GO-COOH and the chain of PVA connected in the form of carboxylic ester, and GO-COOPVA film is composed of GO-COOPVA, and the thermal stability of GO-COOPVA film obviously improves in comparison with PVA film, and the surface resistivity of GO-COOPVA film clearly decreases. Copyright © 2017 Elsevier B.V. All rights reserved.

Technical Evaluation Report 37: Assistive Software for Disabled Learners

Directory of Open Access Journals (Sweden)

Jon Baggaley

2004-11-01

Full Text Available Previous reports in this series (#32 and 36 have discussed online software features of value to disabled learners in distance education. The current report evaluates four specific assistive software products with useful features for visually and hearing impaired learners: ATutor, ACollab, Natural Voice, and Just Vanilla. The evaluative criteria discussed include the purpose, uses, costs, and features of each software product, all considered primarily from the accessibility perspective.

Copper-assisted, anti-reflection etching of silicon surfaces

Science.gov (United States)

Toor, Fatima; Branz, Howard

2014-08-26

A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

Optimization of ultrasonic assisted extraction of antioxidants from black soybean (Glycine max var) sprouts using response surface methodology.

Science.gov (United States)

Lai, Jixiang; Xin, Can; Zhao, Ya; Feng, Bing; He, Congfen; Dong, Yinmao; Fang, Yun; Wei, Shaomin

2013-01-16

Response surface methodology (RSM) using a central composite design (CCD) was employed to optimize the conditions for extraction of antioxidants from black soybean (Glycine max var) sprouts. Three influencing factors: liquid-solid ratio, period of ultrasonic assisted extraction and extraction temperature were investigated in the ultrasonic aqueous extraction. Then Response Surface Methodology (RSM) was applied to optimize the extraction process focused on DPPH radical-scavenging capacity of the antioxidants with respect to the above influencing factors. The best combination of each significant factor was determined by RSM design and optimum pretreatment conditions for maximum radical-scavenging capacity were established to be liquid-solid ratio of 29.19:1, extraction time of 32.13 min, and extraction temperature of 30 °C. Under these conditions, 67.60% of DPPH radical-scavenging capacity was observed experimentally, similar to the theoretical prediction of 66.36%.

Specific features of NH3 and plasma-assisted MBE in the fabrication of III-N HEMT heterostructures

International Nuclear Information System (INIS)

Alexeev, A. N.; Krasovitsky, D. M.; Petrov, S. I.; Chaly, V. P.; Mamaev, V. V.; Sidorov, V. G.

2015-01-01

The specific features of how nitride HEMT heterostructures are produced by NH 3 and plasma-assisted (PA) molecular-beam epitaxy (MBE) are considered. It is shown that the use of high-temperature AlN/AlGaN buffer layers grown with ammonia at extremely high temperatures (up to 1150°C) can drastically improve the structural perfection of the active GaN layers and reduce the dislocation density in these layers to values of 9 × 10 8 −1 × 10 9 cm −2 . The use of buffer layers of this kind makes it possible to obtain high-quality GaN/AlGaN heterostructures by both methods. At the same time, in contrast to ammonia MBE which is difficult to apply at T < 500°C (because of the low efficiency of ammonia decomposition), PA MBE is rather effective at low temperatures, e.g., for the growth of InAlN layers lattice-matched with GaN. The results obtained in the MBE growth of AlN/AlGaN/GaN/InAlN heterostructures by both PA-MBE and NH 3 -MBE with an extremely high ammonia flux are demonstrated

Improving embryo quality in assisted reproduction

NARCIS (Netherlands)

Mantikou, E.

2013-01-01

The goal of this thesis was to improve embryo quality in assisted reproductive technologies by gaining more insight into human preimplantation embryo development and by improving in vitro culture conditions. To do so, we investigated an intriguing feature of the human preimplantation embryo, i.e.

Hyperspatial Thermal Imaging of Surface Hydrothermal Features at Pilgrim Hot Springs, Alaska using a small Unmanned Aerial System (sUAS)

Science.gov (United States)

Haselwimmer, C. E.; Wilson, R.; Upton, C.; Prakash, A.; Holdmann, G.; Walker, G.

2013-12-01

Thermal remote sensing provides a valuable tool for mapping and monitoring surface hydrothermal features associated with geothermal activity. The increasing availability of low-cost, small Unmanned Aerial Systems (sUAS) with integrated thermal imaging sensors offers a means to undertake very high spatial resolution (hyperspatial), quantitative thermal remote sensing of surface geothermal features in support of exploration and long-term monitoring efforts. Results from the deployment of a quadcopter sUAS equipped with a thermal camera over Pilgrim Hot Springs, Alaska for detailed mapping and heat flux estimation for hot springs, seeps, and thermal pools are presented. Hyperspatial thermal infrared imagery (4 cm pixels) was acquired over Pilgrim Hot Springs in July 2013 using a FLIR TAU 640 camera operating from an Aeryon Scout sUAS flying at an altitude of 40m. The registered and mosaicked thermal imagery is calibrated to surface temperature values using in-situ measurements of uniform blackbody tarps and the temperatures of geothermal and other surface pools acquired with a series of water temperature loggers. Interpretation of the pre-processed thermal imagery enables the delineation of hot springs, the extents of thermal pools, and the flow and mixing of individual geothermal outflow plumes with an unprecedented level of detail. Using the surface temperatures of thermal waters derived from the FLIR data and measured in-situ meteorological parameters the hot spring heat flux and outflow rate is calculated using a heat budget model for a subset of the thermal drainage. The heat flux/outflow rate estimates derived from the FLIR data are compared against in-situ measurements of the hot spring outflow rate recorded at the time of the thermal survey.

Comparison of single-step reverse transepithelial all-surface laser ablation (ASLA) to alcohol-assisted photorefractive keratectomy.

Science.gov (United States)

Aslanides, Ioannis M; Padroni, Sara; Arba Mosquera, Samuel; Ioannides, Antonis; Mukherjee, Achyut

2012-01-01

To evaluate postoperative pain, corneal epithelial healing, development of corneal haze, refractive outcomes, and corneal aberrations in a novel one-step, modified transepithelial photorefractive keratectomy (PRK), termed All-surface laser ablation (ASLA), compared to conventional, alcohol-assisted PRK. Sixty eyes of 30 myopic patients were prospectively recruited to a randomized fellow eye study. Patients underwent conventional alcohol-assisted PRK in one eye (control group) and ASLA-modified transepithelial PRK in the other (30 eyes in each treatment arm). Primary endpoints were postoperative pain and haze scores at 1 day, 3 days, 1 week, and 1, 3, 6, and 12 months. Secondary endpoints included visual acuity at 1, 3, 6, and 12 months, corneal aberrations at 3, 6, and 12 months, and early and late onset haze. Refractive predictability, safety, and efficacy of the two methods were considered. The average age of the cohort was 29 years (standard deviation [SD]: 9; range: 18-46), and the average spherical equivalent refractive error was -4.18 diopters (SD: 1.9). At 3 days after surgery, the average pain score was 64% lower in the ASLA group (P < 0.0005). At this point, 96% of ASLA eyes had no epithelial defect, whereas 43% in the alcohol-assisted group did not achieve complete epithelial healing, and required replacement of bandage contact lens. The haze level was consistently lower in the ASLA group at all time points from 1 to 6 months. This study shows that the ASLA technique may have a future role in refractive surgery, due to the fact that it offers faster epithelial healing, lower pain scores, and significantly less haze formation.

The Word Composite Effect Depends on Abstract Lexical Representations But Not Surface Features Like Case and Font

Directory of Open Access Journals (Sweden)

Paulo Ventura

2017-06-01

Full Text Available Prior studies have shown that words show a composite effect: When readers perform a same-different matching task on a target-part of a word, performance is affected by the irrelevant part, whose influence is severely reduced when the two parts are misaligned. However, the locus of this word composite effect is largely unknown. To enlighten it, in two experiments, Portuguese readers performed the composite task on letter strings: in Experiment 1, in written words varying in surface features (between-participants: courier, notera, alternating-cAsE, and in Experiment 2 in pseudowords. The word composite effect, signaled by a significant interaction between alignment of the two word parts and congruence between parts was found in the three conditions of Experiment 1, being unaffected by NoVeLtY of the configuration or by handwritten form. This effect seems to have a lexical locus, given that in Experiment 2 only the main effect of congruence between parts was significant and was not modulated by alignment. Indeed, the cross-experiment analysis showed that words presented stronger congruence effects than pseudowords only in the aligned condition, because when misaligned the whole lexical item configuration was disrupted. Therefore, the word composite effect strongly depends on abstract lexical representations, as it is unaffected by surface features and is specific to lexical items.

The Word Composite Effect Depends on Abstract Lexical Representations But Not Surface Features Like Case and Font.

Science.gov (United States)

Ventura, Paulo; Fernandes, Tânia; Leite, Isabel; Almeida, Vítor B; Casqueiro, Inês; Wong, Alan C-N

2017-01-01

Prior studies have shown that words show a composite effect: When readers perform a same-different matching task on a target-part of a word, performance is affected by the irrelevant part, whose influence is severely reduced when the two parts are misaligned. However, the locus of this word composite effect is largely unknown. To enlighten it, in two experiments, Portuguese readers performed the composite task on letter strings: in Experiment 1, in written words varying in surface features (between-participants: courier, notera, alternating-cAsE), and in Experiment 2 in pseudowords. The word composite effect, signaled by a significant interaction between alignment of the two word parts and congruence between parts was found in the three conditions of Experiment 1, being unaffected by NoVeLtY of the configuration or by handwritten form. This effect seems to have a lexical locus, given that in Experiment 2 only the main effect of congruence between parts was significant and was not modulated by alignment. Indeed, the cross-experiment analysis showed that words presented stronger congruence effects than pseudowords only in the aligned condition, because when misaligned the whole lexical item configuration was disrupted. Therefore, the word composite effect strongly depends on abstract lexical representations, as it is unaffected by surface features and is specific to lexical items.

Fabrication of surface micro- and nanostructures for superhydrophobic surfaces in electric and electronic applications

Science.gov (United States)

Xiu, Yonghao

our understanding of the roughness effect on superhydrophobicity (both contact angle and hysteresis), structured surfaces from polybutadiene, polyurethane, silica, and Si etc. were successfully prepared. For engineering applications of superhydrophobic surfaces, stability issues regarding UV, mechanical robustness and humid environment need to be investigated. Among these factors, UV stability is the first one to be studied. However, most polymer surfaces we prepared failed the purpose. Silica surfaces with excellent UV stability were prepared. This method consists of preparation of rough silica surfaces, thermal treatment and the following surface hydrophobization by fluoroalkyl silane treatment. Fluoroalkyl groups are UV stable and the underlying species are silica which is also UV stable (UV transparent). UV stability on the surface currently is 5,500 h according the standard test method of ASTM D 4329. No degradation on surface superhydrophobicity was observed. New methods for preparing superhydrophobic and transparent silica surfaces were investigated using urea-choline chloride eutectic liquid to generate fine roughness and reduce the cost for preparation of surface structures. Another possible application for self-cleaning in photovoltaic panels was investigated on Si surfaces by construction of the two-scale rough structures followed by fluoroalkyl silane treatment. Metal (Au) assisted etching was employed to fabricate nanostructures on micrometer pyramid surfaces. The light reflection on the prepared surfaces was investigated. After surface texturing using KOH etching for micrometer pyramids and the following nanostructure using metal assisted etching, surface light reflection reduced to a minimum value which shows that this surface texturing technique is highly promising for improving the photovoltaic efficiency while imparting photovoltaics the self-cleaning feature. This surface is also expected to be UV stable due to the same fluoroalkyl silane used

Human-Assisted AI: an Intelligence Augmentation Approach

OpenAIRE

Alicea, Bradly

2018-01-01

As a flavor of Human-Computer Interaction (HCI), Human-Assisted AI can serve to both augment both human performance and artificial systems. This talk will feature a discussion of Human-assisted AI as an instance of Intelligence Augmentation (IA). We will discuss instances of weak and strong IA, in addition to contemporary examples of and paths forward for such systems. In the variety of models presented, data plays a critical role in the structure of interactions between human and artificial ...

Do Particular Design Features Assist People with Aphasia to Comprehend Text? An Exploratory Study

Science.gov (United States)

Wilson, Lucy; Read, Jennifer

2016-01-01

Background: Much of the evidence underlying guidelines for producing accessible information for people with aphasia focuses on client preference for particular design features. There is limited evidence regarding the effects of these features on comprehension. Aims: To examine the effects of specific design features on text comprehension. It was…

Solar-assisted low energy dwellings

Energy Technology Data Exchange (ETDEWEB)

Esbensen, T V

1980-02-01

The Zero Energy House Group was formed as a subproject of the CCMS Solar Energy Pilot Study in 1974 by seven participating countries experimenting with solar-assisted low-energy dwellings for temperate and northern European climatic conditions. A Zero Energy House is one in which solar energy is used to meet the reduced energy needs of buildings incorporating various thermal energy conservation features. This final report of the Zero Energy House Group includes brief descriptions of 13 major low-energy dwellings in the participating CCMS countries. An overall assessment of the state-of-the-art in solar-assisted low-energy dwellings is also included.

An Effective Vacuum Assisted Extraction Method for the Optimization of Labdane Diterpenoids from Andrographis paniculata by Response Surface Methodology

Directory of Open Access Journals (Sweden)

Ya-Qi Wang

2014-12-01

Full Text Available An effective vacuum assisted extraction (VAE technique was proposed for the first time and applied to extract bioactive components from Andrographis paniculata. The process was carefully optimized by response surface methodology (RSM. Under the optimized experimental conditions, the best results were obtained using a boiling temperature of 65 °C, 50% ethanol concentration, 16 min of extraction time, one extraction cycles and a 12:1 liquid-solid ratio. Compared with conventional ultrasonic assisted extraction and heat reflux extraction, the VAE technique gave shorter extraction times and remarkable higher extraction efficiency, which indicated that a certain degree of vacuum gave the solvent a better penetration of the solvent into the pores and between the matrix particles, and enhanced the process of mass transfer. The present results demonstrated that VAE is an efficient, simple and fast method for extracting bioactive components from A. paniculata, which shows great potential for becoming an alternative technique for industrial scale-up applications.

An effective vacuum assisted extraction method for the optimization of labdane diterpenoids from Andrographis paniculata by response surface methodology.

Science.gov (United States)

Wang, Ya-Qi; Wu, Zhen-Feng; Ke, Gang; Yang, Ming

2014-12-31

An effective vacuum assisted extraction (VAE) technique was proposed for the first time and applied to extract bioactive components from Andrographis paniculata. The process was carefully optimized by response surface methodology (RSM). Under the optimized experimental conditions, the best results were obtained using a boiling temperature of 65 °C, 50% ethanol concentration, 16 min of extraction time, one extraction cycles and a 12:1 liquid-solid ratio. Compared with conventional ultrasonic assisted extraction and heat reflux extraction, the VAE technique gave shorter extraction times and remarkable higher extraction efficiency, which indicated that a certain degree of vacuum gave the solvent a better penetration of the solvent into the pores and between the matrix particles, and enhanced the process of mass transfer. The present results demonstrated that VAE is an efficient, simple and fast method for extracting bioactive components from A. paniculata, which shows great potential for becoming an alternative technique for industrial scale-up applications.

Prototypic Features of Loneliness in a Stratified Sample of Adolescents

DEFF Research Database (Denmark)

Lasgaard, Mathias; Elklit, Ask

2009-01-01

Dominant theoretical approaches in loneliness research emphasize the value of personality characteristics in explaining loneliness. The present study examines whether dysfunctional social strategies and attributions in lonely adolescents can be explained by personality characteristics...... guidance and intervention. Thus, professionals need to be knowledgeable about prototypic features of loneliness in addition to employing a pro-active approach when assisting adolescents who display prototypic features....

Nanorods on surface of GaN-based thin-film LEDs deposited by post-annealing after photo-assisted chemical etching

OpenAIRE

Chen, Lung-Chien; Lin, Wun-Wei; Liu, Te-Yu

2017-01-01

This study investigates the optoelectronic characteristics of gallium nitride (GaN)-based thin-film light-emitting diodes (TF-LEDs) that are formed by a two-step transfer process that involves wet etching and post-annealing. In the two-step transfer process, GaN LEDs were stripped from sapphire substrates by the laser lift-off (LLO) method using a KrF laser and then transferred onto ceramic substrates. Ga-K nanorods were formed on the surface of the GaN-based TF-LEDs following photo-assisted ...

Feature displacement interpolation

DEFF Research Database (Denmark)

Nielsen, Mads; Andresen, Per Rønsholt

1998-01-01

Given a sparse set of feature matches, we want to compute an interpolated dense displacement map. The application may be stereo disparity computation, flow computation, or non-rigid medical registration. Also estimation of missing image data, may be phrased in this framework. Since the features...... often are very sparse, the interpolation model becomes crucial. We show that a maximum likelihood estimation based on the covariance properties (Kriging) show properties more expedient than methods such as Gaussian interpolation or Tikhonov regularizations, also including scale......-selection. The computational complexities are identical. We apply the maximum likelihood interpolation to growth analysis of the mandibular bone. Here, the features used are the crest-lines of the object surface....

Application of Artificial Neural Network and Response Surface Methodology in Modeling of Surface Roughness in WS2 Solid Lubricant Assisted MQL Turning of Inconel 718

Science.gov (United States)

Maheshwera Reddy Paturi, Uma; Devarasetti, Harish; Abimbola Fadare, David; Reddy Narala, Suresh Kumar

2018-04-01

In the present paper, the artificial neural network (ANN) and response surface methodology (RSM) are used in modeling of surface roughness in WS2 (tungsten disulphide) solid lubricant assisted minimal quantity lubrication (MQL) machining. The real time MQL turning of Inconel 718 experimental data considered in this paper was available in the literature [1]. In ANN modeling, performance parameters such as mean square error (MSE), mean absolute percentage error (MAPE) and average error in prediction (AEP) for the experimental data were determined based on Levenberg–Marquardt (LM) feed forward back propagation training algorithm with tansig as transfer function. The MATLAB tool box has been utilized in training and testing of neural network model. Neural network model with three input neurons, one hidden layer with five neurons and one output neuron (3-5-1 architecture) is found to be most confidence and optimal. The coefficient of determination (R2) for both the ANN and RSM model were seen to be 0.998 and 0.982 respectively. The surface roughness predictions from ANN and RSM model were related with experimentally measured values and found to be in good agreement with each other. However, the prediction efficacy of ANN model is relatively high when compared with RSM model predictions.

Computer-Assisted Periodical Routing and Renewal Audit

Science.gov (United States)

Yerkey, A. Neil

1973-01-01

A computer-assisted periodical control system was designed to reduce clerical time required to maintain records in three areas: renewal audit, routing, and records-keeping. The renewal audit features are unusual and are described in detail. (3 references) (Author/DH)

CO2 adsorption-assisted CH4 desorption on carbon models of coal surface: A DFT study

Science.gov (United States)

Xu, He; Chu, Wei; Huang, Xia; Sun, Wenjing; Jiang, Chengfa; Liu, Zhongqing

2016-07-01

Injection of CO2 into coal is known to improve the yields of coal-bed methane gas. However, the technology of CO2 injection-enhanced coal-bed methane (CO2-ECBM) recovery is still in its infancy with an unclear mechanism. Density functional theory (DFT) calculations were performed to elucidate the mechanism of CO2 adsorption-assisted CH4 desorption (AAD). To simulate coal surfaces, different six-ring aromatic clusters (2 × 2, 3 × 3, 4 × 4, 5 × 5, 6 × 6, and 7 × 7) were used as simplified graphene (Gr) carbon models. The adsorption and desorption of CH4 and/or CO2 on these carbon models were assessed. The results showed that a six-ring aromatic cluster model (4 × 4) can simulate the coal surface with limited approximation. The adsorption of CO2 onto these carbon models was more stable than that in the case of CH4. Further, the adsorption energies of single CH4 and CO2 in the more stable site were -15.58 and -18.16 kJ/mol, respectively. When two molecules (CO2 and CH4) interact with the surface, CO2 compels CH4 to adsorb onto the less stable site, with a resulting significant decrease in the adsorption energy of CH4 onto the surface of the carbon model with pre-adsorbed CO2. The Mulliken charges and electrostatic potentials of CH4 and CO2 adsorbed onto the surface of the carbon model were compared to determine their respective adsorption activities and changes. At the molecular level, our results showed that the adsorption of the injected CO2 promoted the desorption of CH4, the underlying mechanism of CO2-ECBM.

Surface-assisted DNA self-assembly: An enzyme-free strategy towards formation of branched DNA lattice

International Nuclear Information System (INIS)

Bhanjadeo, Madhabi M.; Nayak, Ashok K.; Subudhi, Umakanta

2017-01-01

DNA based self-assembled nanostructures and DNA origami has proven useful for organizing nanomaterials with firm precision. However, for advanced applications like nanoelectronics and photonics, large-scale organization of self-assembled branched DNA (bDNA) into periodic lattices is desired. In this communication for the first time we report a facile method of self-assembly of Y-shaped bDNA nanostructures on the cationic surface of Aluminum (Al) foil to prepare periodic two dimensional (2D) bDNA lattice. Particularly those Y-shaped bDNA structures having smaller overhangs and unable to self-assemble in solution, they are easily assembled on the surface of Al foil in the absence of ligase. Field emission scanning electron microscopy (FESEM) analysis shows homogenous distribution of two-dimensional bDNA lattices across the Al foil. When the assembled bDNA structures were recovered from the Al foil and electrophoresed in nPAGE only higher order polymeric bDNA structures were observed without a trace of monomeric structures which confirms the stability and high yield of the bDNA lattices. Therefore, this enzyme-free economic and efficient strategy for developing bDNA lattices can be utilized in assembling various nanomaterials for functional molecular components towards development of DNA based self-assembled nanodevices. - Highlights: • Al foil surface-assisted self-assembly of monomeric structures into larger branched DNA lattice. • FESEM study confirms the uniform distribution of two-dimensional bDNA lattice structures across the surface of Al foil. • Enzyme-free and economic strategy to prepare higher order structures from simpler DNA nanostructures have been confirmed by recovery assay. • Use of well proven sequences for the preparation of pure Y-shaped monomeric DNA nanostructure with high yield.

Alexa, Siri, Cortana, and More: An Introduction to Voice Assistants.

Science.gov (United States)

Hoy, Matthew B

2018-01-01

Voice assistants are software agents that can interpret human speech and respond via synthesized voices. Apple's Siri, Amazon's Alexa, Microsoft's Cortana, and Google's Assistant are the most popular voice assistants and are embedded in smartphones or dedicated home speakers. Users can ask their assistants questions, control home automation devices and media playback via voice, and manage other basic tasks such as email, to-do lists, and calendars with verbal commands. This column will explore the basic workings and common features of today's voice assistants. It will also discuss some of the privacy and security issues inherent to voice assistants and some potential future uses for these devices. As voice assistants become more widely used, librarians will want to be familiar with their operation and perhaps consider them as a means to deliver library services and materials.

The development of cones and associated features on ion bombarded copper

International Nuclear Information System (INIS)

Whitton, J.L.; Williams, J.S.

1977-01-01

Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other surface features is a pre-requisite to cone generation in high-purity crystalline substrates. The authors suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either preexisting or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (Auth.)

The features of chlorophyll concentration long-standing dynamics in the ocean surface layer (comparison of czcs and seawifs data)

Science.gov (United States)

Shevyrnogov, A.; Vysotskaya, G.

To preserve biosphere and make its utilization expedient makes imperative to comprehend in depth long-standing dynamics of the primary production process on our planet. Variability of chlorophyll concentration in the ocean is one of the most important components of this process. However, hard access and large size of the water surface make its investigation labor-consuming. Besides, the dependence of primary production on high variability of hydrophysical phenomena in the ocean (fluctuations of currents, frontal zones, etc.) makes the location of points for measuring the chlorophyll concentration dynamics significant. In this work the long-standing changes in chlorophyll concentration in the surface layer of the ocean have been analyzed on the basis of the CZCS data for 7.5 years and the SeaWiFS data from 1997 to 2003. It was shown that the average chlorophyll concentration calculated at all investigated area is varied moderately. However when analyzing spatially local trends, it was detected that areas exist with stable rise and fall of chlorophyll concentration. Some interesting features of the long-standing dynamics of chlorophyll concentration several interesting features were found. There are the various directions of long-term trends (constant increase or decrease) that cannot be explained only by large-scale hydrological phenomena in the ocean (currents, upwellings etc.). The next feature is a difference between the trends revealed by using the CZCS data and the trends based on the SeaWiFS data. Thus, the obtained results allow the possibility of identification of the ocean biota role in the global biospheric gas exchange.

Grain surface features and clay mineralogy of the quaternary sediments from Western Deccan Trap Region, India, and their palaeoclimatic significance

Directory of Open Access Journals (Sweden)

Veena U. Joshi

2011-06-01

Full Text Available Quartz sand grains obtained from a deeply gullied topography along the banks of two tributaries of River Pravara in Maharashtra (India have been examined with a scanning electron microscope (SEM. Quartz grains have been selected after a heavy mineral separation and micro-photographs of each grain were taken at various angles and magnifications. The sediments reveal features resulting from mechanical grinding as well as from chemical alteration. Conchoidal fractures, cleavage planes, grooves, v-shaped indentations etc. are the mechanical features documented on the grains whereas solution pits of varying sizes and intensity, precipitation surfaces, oriented v-pits, solution crevasses and etching are the features of chemical origin. Several evidences indicate that the samples have undergone digenetic changes. Few grains show the features of intense chemical breakdown. The overall assemblages of the grain surface features suggest that the samples have been subjected to subaqueous transport for a considerable period of time. The minor chemical features such as solution pits or semi circular arcuate steps found in abundance on these grains are due to the dissolution of the sediments in a low energy fluviatile environment. For clay mineralogy, fractions between <2 and <0.2 mm were separated out from the sediments. The clay fractions were then subjected to examination by X-ray diffraction (XRD of oriented K/Ca saturated samples using a Philips Diffractometer and Ni-filtered Cu Ka radiation with the scanning speed of 10 2Ө min -1. The main clay minerals for all the samples are identical and show the presence of hydroxy-interlayered smectites with minor quantities of mica, kaolinite, smectites, quartz and feldspar. The first weathering product of the Deccan Basalt (DB is the dioctahedral smectite. Since the present semi aridic climatic condition of the study area can not transform a smectite to HIS and either smectite to kaolin, it is quite likely that

A feature dictionary supporting a multi-domain medical knowledge base.

Science.gov (United States)

Naeymi-Rad, F

1989-01-01

Because different terminology is used by physicians of different specialties in different locations to refer to the same feature (signs, symptoms, test results), it is essential that our knowledge development tools provide a means to access a common pool of terms. This paper discusses the design of an online medical dictionary that provides a solution to this problem for developers of multi-domain knowledge bases for MEDAS (Medical Emergency Decision Assistance System). Our Feature Dictionary supports phrase equivalents for features, feature interactions, feature classifications, and translations to the binary features generated by the expert during knowledge creation. It is also used in the conversion of a domain knowledge to the database used by the MEDAS inference diagnostic sessions. The Feature Dictionary also provides capabilities for complex queries across multiple domains using the supported relations. The Feature Dictionary supports three methods for feature representation: (1) for binary features, (2) for continuous valued features, and (3) for derived features.

Plasma-assisted self-formation of nanotip arrays on the surface of Cu(In,Ga)Se{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Zimin, Sergey P.; Mokrov, Dmitry A. [Yaroslavl State University (Russian Federation); Gorlachev, Egor S.; Amirov, Ildar I.; Naumov, Viktor V. [Institute of Physics and Technology, Russian Academy of Sciences, Yaroslavl (Russian Federation); Gremenok, Valery F. [Scientific-Practical Materials Research Center, NAS of Belarus, Minsk (Belarus); Bente, Klaus [Applied Mineralogy, University Tuebingen (Germany); Kim, Woo Y. [Fusion Research Center, Hoseo University, Asan-City (Korea, Republic of)

2017-06-15

In this paper, we report on the phenomenon of nanostructure self-formation on the surface of Cu(In,Ga)Se{sub 2} (CIGS) thin films during inductively coupled argon plasma treatment with its duration varied from 10 to 120 s. The initial films were grown on glass substrates using the selenization technique. During the CIGS film surface treatment in the high-density low-pressure radio-frequency inductively coupled argon plasma there took place a formation of arrays of uniform vertical nanostructures, which shape with increasing processing duration changed from nanocones to nanorods and back to nanocones. A model of the nanotip plasma-assisted self-formation associated with the implementation of micromasking and vapor-liquid-solid mechanisms involving metallic In-Ga (In-Ga-Cu) liquid alloy droplets is proposed. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Carrier dynamics and surface vibration-assisted Auger recombination in porous silicon

Science.gov (United States)

Zakar, Ammar; Wu, Rihan; Chekulaev, Dimitri; Zerova, Vera; He, Wei; Canham, Leigh; Kaplan, Andrey

2018-04-01

Excitation and recombination dynamics of the photoexcited charge carriers in porous silicon membranes were studied using a femtosecond pump-probe technique. Near-infrared pulses (800 nm, 60 fs) were used for the pump while, for the probe, we employed different wavelengths in the range between 3.4 and 5 μ m covering the medium wavelength infrared range. The data acquired in these experiments consist of simultaneous measurements of the transmittance and reflectance as a function of the delay time between the pump and probe for different pump fluences and probe wavelengths. To evaluate the results, we developed an optical model based on the two-dimensional Maxwell-Garnett formula, incorporating the free-carrier Drude contribution and nonuniformity of the excitation by the Wentzel-Kramers-Brillouin model. This model allowed the retrieval of information about the carrier density as a function of the pump fluence, time, and wavelength. The carrier density data were analyzed to reveal that the recombination dynamics is governed by Shockley-Read-Hall and Auger processes, whereas the diffusion has an insignificant contribution. We show that, in porous silicon samples, the Auger recombination process is greatly enhanced at the wavelength corresponding to the infrared-active vibrational modes of the molecular impurities on the surface of the pores. This observation of surface-vibration-assisted Auger recombination is not only for porous silicon in particular, but for low-dimension and bulk semiconductors in general. We estimate the time constants of Shockley-Read-Hall and Auger processes, and demonstrate their wavelength dependence for the excited carrier density in the range of 1018-10191 /cm3 . We demonstrate that both processes are enhanced by up to three orders of magnitude with respect to the bulk counterpart. In addition, we provide a plethora of the physical parameters evaluated from the experimental data, such as the dielectric function and its dependence on the

Elementary epistemological features of machine intelligence

OpenAIRE

Horvat, Marko

2008-01-01

Theoretical analysis of machine intelligence (MI) is useful for defining a common platform in both theoretical and applied artificial intelligence (AI). The goal of this paper is to set canonical definitions that can assist pragmatic research in both strong and weak AI. Described epistemological features of machine intelligence include relationship between intelligent behavior, intelligent and unintelligent machine characteristics, observable and unobservable entities and classification of in...

Bladder cancer treatment response assessment with radiomic, clinical, and radiologist semantic features

Science.gov (United States)

Gordon, Marshall N.; Cha, Kenny H.; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Cohan, Richard H.; Caoili, Elaine M.; Paramagul, Chintana; Alva, Ajjai; Weizer, Alon Z.

2018-02-01

We are developing a decision support system for assisting clinicians in assessment of response to neoadjuvant chemotherapy for bladder cancer. Accurate treatment response assessment is crucial for identifying responders and improving quality of life for non-responders. An objective machine learning decision support system may help reduce variability and inaccuracy in treatment response assessment. We developed a predictive model to assess the likelihood that a patient will respond based on image and clinical features. With IRB approval, we retrospectively collected a data set of pre- and post- treatment CT scans along with clinical information from surgical pathology from 98 patients. A linear discriminant analysis (LDA) classifier was used to predict the likelihood that a patient would respond to treatment based on radiomic features extracted from CT urography (CTU), a radiologist's semantic feature, and a clinical feature extracted from surgical and pathology reports. The classification accuracy was evaluated using the area under the ROC curve (AUC) with a leave-one-case-out cross validation. The classification accuracy was compared for the systems based on radiomic features, clinical feature, and radiologist's semantic feature. For the system based on only radiomic features the AUC was 0.75. With the addition of clinical information from examination under anesthesia (EUA) the AUC was improved to 0.78. Our study demonstrated the potential of designing a decision support system to assist in treatment response assessment. The combination of clinical features, radiologist semantic features and CTU radiomic features improved the performance of the classifier and the accuracy of treatment response assessment.

Adaptive Feature Based Control of Compact Disk Players

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob; Vidal, Enrique Sanchez

2005-01-01

Many have experienced the problem that their Compact Disc players have difficulties playing Compact Discs with surface faults like scratches and fingerprints. The cause of this is due to the two servo control loops used to keep the Optical Pick-up Unit focused and radially on the information track...... of the Compact Disc. The problem is to design servo controllers which are well suited for handling surface faults which disturb the position measurement and still react sufficiently against normal disturbances like mechanical shocks. In previous work of the same authors a feature based control scheme for CD......-players playing CDs with surface fault is derived and described. This feature based control scheme uses precomputed base to remove the surface fault influence from the position measurements. In this paper an adaptive version of the feature based control scheme is proposed and described. This adaptive scheme can...

Visible light assisted photodegradation of halocarbons on the dye modified TiO{sub 2} surface using visible light

Energy Technology Data Exchange (ETDEWEB)

Chatterjee, Debabrata; Dasgupta, Shimanti [Chemistry Section, Central Mechanical Engineering Research Institute, Durgapur 713209 (India); N Rao, Nageswar [Wastewater Technology Division, National Environmental Engineering Research Institute, Nagpur 400020 (India)

2006-05-05

Visible light assisted photodegradation of various halocarbons, viz. chloro-phenols, trichloroethylene, 1,2-dichloroethane and 1,4-dichlorobenzene, has been achieved on the surface of dye-modified TiO{sub 2} semiconductor. Thionine, eosinY, rhodamineB, methyleneblue, nileblueA and safranineO were used for the modification of TiO{sub 2} semiconductor photocatalyst. After 5h of irradiation with a 150W Xenon lamp, over 55-72% degradation of pollutants has been achieved. A working mechanism involving excitation of surface adsorbed dye, followed by charge injection into the TiO{sub 2} conduction band and formation of reactive {sup *}O{sub 2}{sup -}/{sup *}HO{sub 2} radicals, is proposed for the degradation of the enlisted organics to carbon dioxide. Efficacy of the photocatalytic system towards halocarbon degradation has been discussed in regard to excited state redox properties of the dyes selected for this study. Formation of {sup *}O{sub 2}{sup -} radical has been substantiated by using a chemiluminescent probe luminol. (author)

Printing-assisted surface modifications of patterned ultrafiltration membranes

International Nuclear Information System (INIS)

Wardrip, Nathaniel C.; Dsouza, Melissa; Urgun-Demirtas, Meltem; Snyder, Seth W.

2016-01-01

Understanding and restricting microbial surface attachment will enhance wastewater treatment with membranes. We report a maskless lithographic patterning technique for the generation of patterned polymer coatings on ultrafiltration membranes. Polyethylene glycol, zwitterionic, or negatively charged hydrophilic polymer compositions in parallel- or perpendicular-striped patterns with respect to feed flow were evaluated using wastewater. Membrane fouling was dependent on the orientation and chemical composition of the coatings. Modifications reduced alpha diversity in the attached microbial community (Shannon indices decreased from 2.63 to 1.89) which nevertheless increased with filtration time. Sphingomonas species, which condition membrane surfaces and facilitate cellular adhesion, were depleted in all modified membranes. Microbial community structure was significantly different between control, different patterns, and different chemistries. Lastly, this study broadens the tools for surface modification of membranes with polymer coatings and for understanding and optimization of antifouling surfaces.

Various Landscapes and Features on Europa

Science.gov (United States)

1997-01-01

These 15 frames show the great variety of surface features on Jupiter's icy moon, Europa, which have been revealed by the Galileo spacecraft Solid State Imaging (CCD) system during its first six orbits around Jupiter from June 1996 to February 1997. North is to the top of each of the images. The features seen on Europa's surface document both internal and external processes shaping the icy crust. Internal processes and the possible presence of liquid water beneath the ice are indicated by features such as 'dark spots', lobe-shaped flow features, 'puddles','mottled terrain', knobs, pits, and the darker areas along ridges and triple bands.Europa is subjected to constant tugging from the giant planet, Jupiter, as well as from its neighboring moons, Io and Ganymede. This causes 'tidal' forces that affect Europa's interior and surface. Evidence for such forces includes ridges, fractures, wedge-shaped bands, and areas of 'chaos'. Some of these features result from alternate extension and compression buckling and pulling apart Europa's icy shell.Impact craters document external effects on a planet's surface. Although present on Europa, impact craters are relatively scarce compared to the number seen on Ganymede, Callisto, and on the surfaces of most other 'rocky' planets and moons in our solar system. This scarcity of craters suggests that the surface of Europa is very young. 'Maculae' on Europa may be the scars from large impact events.These images have resolutions from 27 meters (89 feet) to 7 kilometers (4.3 miles) per picture element (pixel) and were taken by Galileo at ranges of 2,500 kilometers (1,525 miles) to 677,000 kilometers (413,000 miles) from Europa.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo

Study on chemical mechanical polishing of silicon wafer with megasonic vibration assisted.

Science.gov (United States)

Zhai, Ke; He, Qing; Li, Liang; Ren, Yi

2017-09-01

Chemical mechanical polishing (CMP) is the primary method to realize the global planarization of silicon wafer. In order to improve this process, a novel method which combined megasonic vibration to assist chemical mechanical polishing (MA-CMP) is developed in this paper. A matching layer structure of polishing head was calculated and designed. Silicon wafers are polished by megasonic assisted chemical mechanical polishing and traditional chemical mechanical polishing respectively, both coarse polishing and precision polishing experiments were carried out. With the use of megasonic vibration, the surface roughness values Ra reduced from 22.260nm to 17.835nm in coarse polishing, and the material removal rate increased by approximately 15-25% for megasonic assisted chemical mechanical polishing relative to traditional chemical mechanical polishing. Average Surface roughness values Ra reduced from 0.509nm to 0.387nm in precision polishing. The results show that megasonic assisted chemical mechanical polishing is a feasible method to improve polishing efficiency and surface quality. The material removal and finishing mechanisms of megasonic vibration assisted polishing are investigated too. Copyright © 2017 Elsevier B.V. All rights reserved.

Crystal surface analysis using matrix textural features classified by a Probabilistic Neural Network

International Nuclear Information System (INIS)

Sawyer, C.R.; Quach, V.T.; Nason, D.; van den Berg, L.

1991-01-01

A system is under development in which surface quality of a growing bulk mercuric iodide crystal is monitored by video camera at regular intervals for early detection of growth irregularities. Mercuric iodide single crystals are employed in radiation detectors. A microcomputer system is used for image capture and processing. The digitized image is divided into multiple overlappings subimage and features are extracted from each subimage based on statistical measures of the gray tone distribution, according to the method of Haralick [1]. Twenty parameters are derived from each subimage and presented to a Probabilistic Neural Network (PNN) [2] for classification. This number of parameters was found to be optimal for the system. The PNN is a hierarchical, feed-forward network that can be rapidly reconfigured as additional training data become available. Training data is gathered by reviewing digital images of many crystals during their growth cycle and compiling two sets of images, those with and without irregularities. 6 refs., 4 figs

Films made of cellulose nanofibrils: surface modification by adsorption of a cationic surfactant and characterization by computer-assisted electron microscopy

International Nuclear Information System (INIS)

Syverud, K.; Xhanari, K.; Chinga-Carrasco, G.; Yu, Y.; Stenius, P.

2011-01-01

Films made of nanofibrils were modified by adsorption of a cationic surfactant directly on the film surfaces. The nanofibrils were prepared by 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation and mechanical fibrillation, and were relatively homogeneous in size. The average nanofibril diameter and surface porosity was quantified based on computer-assisted field-emission scanning electron microscopy (FE-SEM). The cationic surfactant used in the adsorption was n-hexadecyl trimethylammonium bromide (cetyltrimethylammonium bromide, CTAB). The adsorption of CTAB was confirmed by Fourier transform infrared (FTIR) spectroscopy and high-resolution transmission electron microscopy (HRTEM) analyses. It was shown that the adsorbed layer of CTAB increased the hydrophobicity, without affecting the tensile index significantly. This capability, combined with the antiseptic properties of CTAB, may be a major advantage for several applications.

Laser assisted hybrid additive manufacturing of thermoelectric modules

Science.gov (United States)

Zhang, Tao; Tewolde, Mahder; Longtin, Jon P.; Hwang, David J.

2017-02-01

Thermoelectric generators (TEGs) are an attractive means to produce electricity, particular from waste heat applications. However, TEGs are almost exclusively manufactured as flat, rigid modules of limited size and shape, and therefore an appropriate mounting for intimate contact of TEGs modules onto arbitrary surfaces represents a significant challenge. In this study, we introduce laser assisted additive manufacturing method to produce multi-layered thermoelectric generator device directly on flat and non-flat surfaces for waste heat recovery. The laser assisted processing spans from laser scribing of thermal sprayed thin films, curing of dispensed thermoelectric inks and selective laser sintering to functionalize thermoelectric materials.

Upwelling filaments are cold, typically narrow features in surface ...

African Journals Online (AJOL)

spamer

They are defined by strong ... transporting coastally upwelled water to the deep ... surface temperature anomaly up to 2°C. The cool temperature signal was restricted to a shallow surface ... towards the important process of exchanges between.

Ultrasonically assisted drilling of rocks

Science.gov (United States)

Mikhailova, N. V.; Onawumi, P. Y.; Roy, A.; Silberschmidt, V. V.

2018-05-01

Conventional drilling of rocks can generate significant damage in the drilled material; a material layer is often split off a back surface of a sample during drilling, negatively affecting its strength. To improve finish quality, ultrasonically assisted drilling (UAD) was employed in two rocks - sandstone and marble. Damage areas in both materials were reduced in UAD when compared to conventional drilling. Reductions in a thrust force and a torque reduction were observed only for UAD in marble; ultrasonic assistance in sandstone drilling did not result in improvements in this regard.

Computer-assisted diagnosis of melanoma.

Science.gov (United States)

Fuller, Collin; Cellura, A Paul; Hibler, Brian P; Burris, Katy

2016-03-01

The computer-assisted diagnosis of melanoma is an exciting area of research where imaging techniques are combined with diagnostic algorithms in an attempt to improve detection and outcomes for patients with skin lesions suspicious for malignancy. Once an image has been acquired, it undergoes a processing pathway which includes preprocessing, enhancement, segmentation, feature extraction, feature selection, change detection, and ultimately classification. Practicality for everyday clinical use remains a vital question. A successful model must obtain results that are on par or outperform experienced dermatologists, keep costs at a minimum, be user-friendly, and be time efficient with high sensitivity and specificity. ©2015 Frontline Medical Communications.

Effect of liquid environment on the titanium surface modification by laser ablation

Energy Technology Data Exchange (ETDEWEB)

Ali, Nisar, E-mail: chnisarali@gmail.com [Laser Laboratories, Institute for Applied Physics, Vienna University of Technology, 1040 Vienna (Austria); Department of Basic Science and Humanities, University of Engineering and Technology Lahore, Faisalabad Campus, Faisalabad (Pakistan); Laser Laboratories, Centre for Advanced Studies in Physics, GC University, 1-Church Road, Lahore (Pakistan); Department of Physics, GC University, Kachehri Road, Lahore (Pakistan); Bashir, Shazia [Laser Laboratories, Centre for Advanced Studies in Physics, GC University, 1-Church Road, Lahore (Pakistan); Umm-i-Kalsoom [Laser Laboratories, Institute for Applied Physics, Vienna University of Technology, 1040 Vienna (Austria); Laser Laboratories, Centre for Advanced Studies in Physics, GC University, 1-Church Road, Lahore (Pakistan); Department of Physics, GC University, Kachehri Road, Lahore (Pakistan); Department of Basic Science and Humanities, University of Engineering and Technology Lahore, Kala Shah Kaku Campus, Lahore (Pakistan); Begum, Narjis [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Rafique, Muhammad Shahid [Department of Physics, University of Engineering and Technology Lahore (Pakistan); Husinsky, Wolfgang [Laser Laboratories, Institute for Applied Physics, Vienna University of Technology, 1040 Vienna (Austria)

2017-05-31

Highlights: • Liquid assisted ablation effects on the titanium under varying number of laser pulses is investigated. • SEM analysis reveals the growth of various features like ripples, dendritic structures, pores, grains and craters. • Raman and XRD analyses shows the presence of TiO{sub 2} & TiH in both media whereas, TiC, TiCxOy are only identified in propanol. • Hardness of ablated Ti explored by Nano indentation is found to decrease with increasing number of pulses in both media. • Relationship between surface, structural and mechanical modifications is established. - Abstract: The effect of liquid environment (de-ionized water and propanol) on surface, structural and mechanical properties of femtosecond laser ablated titanium has been investigated. For this purpose, Ti: sapphire laser (800 nm, 30 fs, 1 kHz) has been employed, at a fluence of 3.6 J/cm{sup 2} in ambient environments of de-ionized water, and propanol for various number of laser pulses i.e. 500, 1000, 1500 and 2000. The surface features, chemical composition, structural analysis and mechanical properties of irradiated targets have been evaluated by using Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X -ray Diffraction (XRD), Raman Spectroscopy and Nano-hardness tester. Various features like dendritic structures, globules, porous granular morphology, cones, crater, circular ripples and thermal stress cracking are observed at the ablated area after irradiation. These features are instigated by various thermal and chemical phenomena induced by laser heating at the solid–liquid interface. Decrease in nano-hardness observed in both ambient environments is attributable to the formation of hydrides after irradiation in both media.

Surface Species and Metal Oxidation State during H2-Assisted NH3-SCR of NOx over Alumina-Supported Silver and Indium

Directory of Open Access Journals (Sweden)

Linda Ström

2018-01-01

Full Text Available Alumina-supported silver and indium catalysts are investigated for the hydrogen-assisted selective catalytic reduction (SCR of NOx with ammonia. Particularly, we focus on the active phase of the catalyst and the formation of surface species, as a function of the gas environment. Diffuse reflectance ultraviolet-visible (UV-vis spectroscopy was used to follow the oxidation state of the silver and indium phases, and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS was used to elucidate the formation of surface species during SCR conditions. In addition, the NOx reduction efficiency of the materials was evaluated using H2-assisted NH3-SCR. The DRIFTS results show that the Ag/Al2O3 sample forms NO-containing surface species during SCR conditions to a higher extent compared to the In/Al2O3 sample. The silver sample also appears to be more reduced by H2 than the indium sample, as revealed by UV-vis spectroscopic experiments. Addition of H2, however, may promote the formation of highly dispersed In2O3 clusters, which previously have been suggested to be important for the SCR reaction. The affinity to adsorb NH3 is confirmed by both temperature programmed desorption (NH3-TPD and in situ DRIFTS to be higher for the In/Al2O3 sample compared to Ag/Al2O3. The strong adsorption of NH3 may inhibit (self-poison the NH3 activation, thereby hindering further reaction over this catalyst, which is also shown by the lower SCR activity compared to Ag/Al2O3.

Surface for dummies

CERN Document Server

Rathbone, Andy

2014-01-01

Make Microsoft's Surface work-and play-just the way you want it to Microsoft's Surface tablet has the features and personality you're looking for, with a robust environment for business computing that doesn't skimp on fun. Surface for Dummies, 2nd Edition explains how Windows 8.1 Pro and Windows RT differ, and helps you decide which Surface model is best for you. Step by step, this book walks you through both the hardware and software features of the Surface, including the touch cover and type cover, Windows RT and Windows 8.1 Pro operating systems, and the coveted Office Home & Student 2013 s

Laser assisted fabrication of random rough surfaces for optoelectronics

Energy Technology Data Exchange (ETDEWEB)

Brissonneau, V., E-mail: vincent.brissonneau@im2np.fr [Thales Optronique SA, Avenue Gay-Lussac, 78995 Elancourt (France); Institut Materiaux Microelectronique Nanosciences de Provence, Aix Marseille Universite, Avenue Escadrille Normandie Niemen, 13397 Marseille (France); Escoubas, L. [Institut Materiaux Microelectronique Nanosciences de Provence, Aix Marseille Universite, Avenue Escadrille Normandie Niemen, 13397 Marseille (France); Flory, F. [Institut Materiaux Microelectronique Nanosciences de Provence, Ecole Centrale Marseille, Marseille (France); Berginc, G. [Thales Optronique SA, Avenue Gay-Lussac, 78995 Elancourt (France); Maire, G.; Giovannini, H. [Institut Fresnel, Aix Marseille Universite, Avenue Escadrille Normandie Niemen, 13397 Marseille (France)

2012-09-15

Highlights: Black-Right-Pointing-Pointer Random rough surfaces are photofabricated using an argon ion laser. Black-Right-Pointing-Pointer Speckle and surface correlation function are linked. Black-Right-Pointing-Pointer Exposure beam is modified allowing tuning the correlation. Black-Right-Pointing-Pointer Theoretical examples are presented. Black-Right-Pointing-Pointer Experimental results are compared with theoretical expectation. - Abstract: Optical surface structuring shows great interest for antireflective or scattering properties. Generally, fabricated surface structures are periodical but random surfaces that offer new degrees of freedom and possibilities by the control of their statistical properties. We propose an experimental method to create random rough surfaces on silicon by laser processing followed by etching. A photoresist is spin coated onto a silicon substrate and then exposed to the scattering of a modified laser beam. The beam modification is performed by using a micromirror matrix allowing laser beam shaping. An example of tuning is presented. An image composed of two white circles with a black background is displayed and the theoretical shape of the correlation is calculated. Experimental surfaces are elaborated and the correlation function calculated from height mapping. We finally compared the experimental and theoretical correlation functions.

Clinical Features of Patients with Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders

Directory of Open Access Journals (Sweden)

Hai Chen

2016-01-01

Conclusion: The different CSF features combined with clinical, magnetic resonance imaging, and serum characteristics between Chinese patients with MS and NMOSD could assist in the differential diagnosis.

Handbook of driver assistance systems basic information, components and systems for active safety and comfort

CERN Document Server

Hakuli, Stephan; Lotz, Felix; Singer, Christina

2016-01-01

This fundamental work explains in detail systems for active safety and driver assistance, considering both their structure and their function. These include the well-known standard systems such as Anti-lock braking system (ABS), Electronic Stability Control (ESC) or Adaptive Cruise Control (ACC). But it includes also new systems for protecting collisions protection, for changing the lane, or for convenient parking. The book aims at giving a complete picture focusing on the entire system. First, it describes the components which are necessary for assistance systems, such as sensors, actuators, mechatronic subsystems, and control elements. Then, it explains key features for the user-friendly design of human-machine interfaces between driver and assistance system. Finally, important characteristic features of driver assistance systems for particular vehicles are presented: Systems for commercial vehicles and motorcycles.

Sensitivity enhancement for nitrophenols using cationic surfactant-modified activated carbon for solid-phase extraction surface-assisted laser desorption/ionization mass spectrometry.

Science.gov (United States)

Chen, Y C; Tsai, M F

2000-01-01

Previous work has demonstrated that a combination of solid-phase extraction with surface-assisted laser desorption/ionization (SPE-SALDI) mass spectrometry can be applied to the determination of trace nitrophenols in water. An improved method to lower the detection limit of this hyphenated technique is described in this present study. Activated carbon powder is used as both the SPE adsorbent and the SALDI solid in the analysis by SPE-SALDI. The surface of the activated carbon is modified by passing an aqueous solution of a cationic surfactant through the SPE cartridge. The results demonstrate that the sensitivity for nitrophenols in the analysis by SPE-SALDI can be improved by using cationic surfactants to modify the surface of the activated carbon. The detection limit for nitrophenols is about 25 ppt based on a signal-to-noise ratio of 3 by sampling from 100 mL of solution. Copyright 2000 John Wiley & Sons, Ltd.

The development of cones and associated features on ion bombarded copper

International Nuclear Information System (INIS)

Whitton, J.L.; Carter, G.; Nobes, M.J.; Williams, J.S.

1977-01-01

Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features, have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other features is a pre-requisite to cone generation in high-purity crystalline substrates. We suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either pre-existing or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (author)

Spent coffee-based activated carbon: specific surface features and their importance for H2S separation process.

Science.gov (United States)

Kante, Karifala; Nieto-Delgado, Cesar; Rangel-Mendez, J Rene; Bandosz, Teresa J

2012-01-30

Activated carbons were prepared from spent ground coffee. Zinc chloride was used as an activation agent. The obtained materials were used as a media for separation of hydrogen sulfide from air at ambient conditions. The materials were characterized using adsorption of nitrogen, elemental analysis, SEM, FTIR, and thermal analysis. Surface features of the carbons depend on the amount of an activation agent used. Even though the residual inorganic matter takes part in the H(2)S retention via salt formation, the porous surface of carbons governs the separation process. The chemical activation method chosen resulted in formation of large volume of pores with sizes between 10 and 30Å, optimal for water and hydrogen sulfide adsorption. Even though the activation process can be optimized/changed, the presence of nitrogen in the precursor (caffeine) is a significant asset of that specific organic waste. Nitrogen functional groups play a catalytic role in hydrogen sulfide oxidation. Copyright © 2011 Elsevier B.V. All rights reserved.

Plasma based Ar+ beam assisted poly(dimethylsiloxane) surface modification

International Nuclear Information System (INIS)

Vladkova, T.G.; Keranov, I.L.; Dineff, P.D.; Youroukov, S.Y.; Avramova, I.A.; Krasteva, N.; Altankov, G.P.

2005-01-01

Plasma based Ar + beam performed in RF (13.56 MHz) low-pressure (200 mTorr) glow discharge (at 100 W, 1200 W and 2500 W) with a serial capacitance was employed for surface modification of poly(dimethylsiloxane) (PDMS) aimed at improvement of its interactions with living cells. The presence of a serial capacitance ensures arise of an ion-flow inside the plasma volume directed toward the treated sample and the vary of the discharge power ensures varied density of the ion-flow. XPS analysis was performed to study the changes in the surface chemical composition of the modified samples and the corresponding changes in the surface energy were monitored by contact angle measurements. We found that plasma based Ar + beam transforms the initially hydrophobic PDMS surface into a hydrophilic one mainly due to a raising of the polar component of the surface tension, this effect being most probably due to an enrichment of the modified surface layer with permanent dipoles of a [SiO x ]-based network and elimination of the original methyl groups. The initial adhesion of human fibroblast cells was studied on the described above plasma based Ar + beam modified and acrylic acid (AA) grafted or not fibronectin (FN) pre-coated or bare surfaces. The cell response seems to be related with the peculiar structure and wettability of the modified PDMS surface layer after plasma based Ar + beam treatment followed or not by AA grafting

A novel type of matrix for surface-assisted laser desorption-ionization mass spectrometric detection of biomolecules using metal-organic frameworks.

Science.gov (United States)

Fu, Chien-Ping; Lirio, Stephen; Liu, Wan-Ling; Lin, Chia-Her; Huang, Hsi-Ya

2015-08-12

A 3D metal-organic framework (MOF) nanomaterial as matrix for surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) and tandem mass spectrometry (MS/MS) was developed for the analysis of complex biomolecules. Unlike other nanoparticle matrices, this MOF nanomaterial does not need chemical modification prior to use. An exceptional signal reproducibility as well as very low background interferences in analyzing mono-/di-saccharides, peptides and complex starch digests demonstrate its high potential for biomolecule assays, especially for small molecules. Copyright © 2015 Elsevier B.V. All rights reserved.

Assisted Suicide in Switzerland: Clarifying Liberties and Claims.

Science.gov (United States)

Hurst, Samia A; Mauron, Alex

2017-03-01

Assisting suicide is legal in Switzerland if it is offered without selfish motive to a person with decision-making capacity. Although the 'Swiss model' for suicide assistance has been extensively described in the literature, the formally and informally protected liberties and claims of assistors and recipients of suicide assistance in Switzerland are incompletely captured in the literature. In this article, we describe the package of rights involved in the 'Swiss model' using the framework of Hohfeldian rights as modified by Wenar. After outlining this framework, we dissect the rights involved in suicide assistance in Switzerland, and compare it with the situation in England and Germany. Based on this approach, we conclude that in Switzerland, claim rights exist for those requesting suicide assistance, and for those who are considering providing such assistance, even though no entitlements exist toward suicide assistance. We then describe the implementation of the 'Swiss model' and difficulties arising within it. Clarifying these issues is important to understand the Swiss situation, to evaluate what features of it may or may not be worth correcting or emulating, and to understand how it can impact requests for suicide assistance in other countries due to 'suicide tourism'. It is also important to understand exactly what sets Switzerland apart from other countries with different legislations regarding suicide assistance. © 2016 John Wiley & Sons Ltd.

Evaluation of mechanism of cold atmospheric pressure plasma assisted polymerization of acrylic acid on low density polyethylene (LDPE) film surfaces: Influence of various gaseous plasma pretreatment

Science.gov (United States)

Ramkumar, M. C.; Pandiyaraj, K. Navaneetha; Arun Kumar, A.; Padmanabhan, P. V. A.; Uday Kumar, S.; Gopinath, P.; Bendavid, A.; Cools, P.; De Geyter, N.; Morent, R.; Deshmukh, R. R.

2018-05-01

Owing to its exceptional physiochemical properties, low density poly ethylene (LDPE) has wide range of tissue engineering applications. Conversely, its inadequate surface properties make LDPE an ineffectual candidate for cell compatible applications. Consequently, plasma-assisted polymerization with a selected precursor is a good choice for enhancing its biocompatibility. The present investigation studies the efficiency of plasma polymerization of acrylic acid (AAC) on various gaseous plasma pretreated LDPE films by cold atmospheric pressure plasma, to enhance its cytocompatibility. The change in chemical composition and surface topography of various gaseous plasma pretreated and acrylic deposited LDPE films has been assessed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The changes in hydrophilic nature of surface modified LDPE films were studied by contact angle (CA) analysis. Cytocompatibility of the AAC/LDPE films was also studied in vitro, using RIN-5F cells. The results acquired by the XPS and AFM analysis clearly proved that cold atmospheric pressure (CAP) plasma assisted polymerization of AAC enhances various surface properties including carboxylic acid functional group density and increased surface roughness on various gaseous plasma treated AAC/LDPE film surfaces. Moreover, contact angle analysis clearly showed that the plasma polymerized samples were hydrophilic in nature. In vitro cytocompatibility analysis undoubtedly validates that the AAC polymerized various plasma pretreated LDPE films surfaces stimulate cell distribution and proliferation compared to pristine LDPE films. Similarly, cytotoxicity analysis indicates that the AAC deposited various gaseous plasma pretreated LDPE film can be considered as non-toxic as well as stimulating cell viability significantly. The cytocompatible properties of AAC polymerized Ar + O2 plasma pretreated LDPE films were found to be more pronounced compared to the other plasma pretreated

Bioinspired polydopamine particles-assisted construction of superhydrophobic surfaces for oil/water separation.

Science.gov (United States)

Shang, Bin; Wang, Yanbing; Peng, Bo; Deng, Ziwei

2016-11-15

Frequent oil spillages and industrial discharge of oils/organic solvents have induced severe environmental pollution and ecological damage, and a great cost in energy and finance has been consumed to solve the problems raised. Therefore, it is urgent to develop a surface hydrophobic modification that can be applied to materials with desired properties of high separation efficiency, excellent selectivity and stable performance in extreme conditions during the oil/water separation. Herein, with combined bioinspirations from mussel adhesive protein (polydopamine) and superhydrophobic lotus leaf (hierarchical structures), we develop a general way to superhydrophobically modify various commercial materials, aiming for the selective removal of oils/organic solvents from water. In this procedure, immersing commercial materials (e.g. melamine sponge, stainless steel mesh, nylon netting and cotton cloth) into water/ethanol/ammonia mixtures at a low concentration of dopamine (DA, 2mg/mL) allows a polydopamine (PDA) coating with a tunable roughness appearing on the substrate in one step. This is because DA can self-polymerize and form PDA particles with a catalyst of ammonia, attaching to any surfaces due to abundant catechol and amine groups in PDA, and ultimately, resulting in hierarchical structures. The subsequent decoration with 1H, 1H, 2H, 2H-perfluorodecanethiol features the surface superhydrophobic and superoleophilic. This approach is straightforward and economic, and carried out under a mild, environmental-benign circumstance, with nonspecific substrate demands. In addition, the as-prepared superhydrophobic materials exhibit excellent separation performances including high absorption/separation capacity, excellent selectivity, and extraordinary recyclability for collecting various oils/organic solvents from water. These superhydrophobic materials have also verified to be highly chemical resistant, environment stable and mechanically durable. Therefore, this

Computer-assisted command and control for Chooz B

International Nuclear Information System (INIS)

Anon.

1995-01-01

A new type of command and control system has been installed at the Chooz B nuclear power plant. A key feature of the system is a man/machine interface designed to provide operators with on-screen assistance more quickly than ever. (Author)

Knowledge-based driver assistance systems traffic situation description and situation feature relevance

CERN Document Server

Huelsen, Michael

2014-01-01

The comprehension of a traffic situation plays a major role in driving a vehicle. Interpretable information forms a basis for future projection, decision making and action performing, such as navigating, maneuvering and driving control. Michael Huelsen provides an ontology-based generic traffic situation description capable of supplying various advanced driver assistance systems with relevant information about the current traffic situation of a vehicle and its environment. These systems are enabled to perform reasonable actions and approach visionary goals such as injury and accident free driv

Short term memory for single surface features and bindings in ageing: A replication study.

Science.gov (United States)

Isella, Valeria; Molteni, Federica; Mapelli, Cristina; Ferrarese, Carlo

2015-06-01

In the present study we replicated a previous experiment investigating visuo-spatial short term memory binding in young and older healthy individuals, in the attempt to verify the pattern of impairment that can be observed in normal elderly for short term memory for single items vs short term memory for bindings. Assessing a larger sample size (25 young and 25 older subjects), using a more appropriate measure of accuracy for a change detection task (A'), and adding the evaluation of speed of performance, we confirmed that old normals show a decline in short term memory for bindings of shape and colour that is of comparable extent, and not major, to the decline in memory for single shapes and single colours. The absence of a specific deficit of short term memory for conjunctions of surface features seems to distinguish cognitive ageing from Alzheimer's Disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Optimization of ultrasonic-assisted extraction of bioactive alkaloid compounds from rhizoma coptidis (Coptis chinensis Franch.) using response surface methodology.

Science.gov (United States)

Teng, Hui; Choi, Yong Hee

2014-01-01

The optimum extraction conditions for the maximum recovery of total alkaloid content (TAC), berberine content (BC), palmatine content (PC), and the highest antioxidant capacity (AC) from rhizoma coptidis subjected to ultrasonic-assisted extraction (UAE) were determined using response surface methodology (RSM). Central composite design (CCD) with three variables and five levels was employed, and response surface plots were constructed in accordance with a second order polynomial model. Analysis of variance (ANOVA) showed that the quadratic model was well fitted and significant for responses of TAC, BC, PC, and AA. The optimum conditions obtained through the overlapped contour plot were as follows: ethanol concentration of 59%, extraction time of 46.57min, and temperature of 66.22°C. Verification experiment was carried out, and no significant difference was found between observed and estimated values for each response, suggesting that the estimated models were reliable and valid for UAE of alkaloids. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Assistance Focus: Latin America/Caribbean

Energy Technology Data Exchange (ETDEWEB)

2017-03-29

The Clean Energy Solutions Center, an initiative of the Clean Energy Ministerial, helps countries throughout the world create policies and programs that advance the deployment of clean energy technologies. Through the Solutions Center's no-cost 'Ask an Expert' service, a team of international experts has delivered assistance to countries in all regions of the world. High-impact examples from the Latin American/Caribbean region are featured here.

Assistance Focus: Asia/Pacific Region

Energy Technology Data Exchange (ETDEWEB)

2017-03-29

The Clean Energy Solutions Center, an initiative of the Clean Energy Ministerial, helps countries throughout the world create policies and programs that advance the deployment of clean energy technologies. Through the Solutions Center's no-cost 'Ask an Expert' service, a team of international experts has delivered assistance to countries in all regions of the world. High-impact examples from the Asia/Pacific region are featured here.

Comparison of single-step reverse transepithelial all-surface laser ablation (ASLA to alcohol-assisted photorefractive keratectomy

Directory of Open Access Journals (Sweden)

Aslanides IM

2012-06-01

Full Text Available Ioannis M Aslanides,1 Sara Padroni,1 Samuel Arba Mosquera,2 Antonis Ioannides,1 Achyut Mukherjee11Emmetropia Mediterranean Eye Institute, Heraklion, Crete, Greece; 2Schwind eye-tech-solutions GmbH, Kleinostheim, GermanyPurpose: To evaluate postoperative pain, corneal epithelial healing, development of corneal haze, refractive outcomes, and corneal aberrations in a novel one-step, modified transepithelial photorefractive keratectomy (PRK, termed All-surface laser ablation (ASLA, compared to conventional, alcohol-assisted PRK.Materials and methods: Sixty eyes of 30 myopic patients were prospectively recruited to a randomized fellow eye study. Patients underwent conventional alcohol-assisted PRK in one eye (control group and ASLA-modified transepithelial PRK in the other (30 eyes in each treatment arm. Primary endpoints were postoperative pain and haze scores at 1 day, 3 days, 1 week, and 1, 3, 6, and 12 months. Secondary endpoints included visual acuity at 1, 3, 6, and 12 months, corneal aberrations at 3, 6, and 12 months, and early and late onset haze. Refractive predictability, safety, and efficacy of the two methods were considered.Results: The average age of the cohort was 29 years (standard deviation [SD]: 9; range: 18–46, and the average spherical equivalent refractive error was -4.18 diopters (SD: 1.9. At 3 days after surgery, the average pain score was 64% lower in the ASLA group (P < 0.0005. At this point, 96% of ASLA eyes had no epithelial defect, whereas 43% in the alcohol-assisted group did not achieve complete epithelial healing, and required replacement of bandage contact lens. The haze level was consistently lower in the ASLA group at all time points from 1 to 6 months.Conclusion: This study shows that the ASLA technique may have a future role in refractive surgery, due to the fact that it offers faster epithelial healing, lower pain scores, and significantly less haze formation.Keywords: cornea, ASLA, PRK, alcohol

Microstructure and Texture in Surface Deformation Layer of Al-Zn-Mg-Cu Alloy Processed by Milling

Directory of Open Access Journals (Sweden)

CHEN Yanxia

2017-12-01

Full Text Available The microstructural and crystallographic features of the surface deformation layer in Al-Zn-Mg-Cu alloy induced by milling were investigated by means of transmission electron microscopy (TEM and precession electron diffraction (PED assisted nanoscale orientation mapping. The result shows that the surface deformation layer is composed by the top surface of equiaxed nanograins/ultrafine grains and the subsurface of lamellar nanograins/ultrafine grains surrounded by coarse grain boundary precipitates (GBPs. The recrystallized nanograins/ultrafine grains in the deformation layer show direct evidence that dynamic recrystallization plays an important role in grain refining process. The GBPs and grain interior precipitates (GIPs show a great difference in size and density with the matrix due to the thermally and mechanically induced precipitate redistribution. The crystallographic texture of the surface deformation layer is proved to be a mixture of approximate copper{112}, rotated cube{001} and F {111}. The severe shear deformation of the surface induced by milling is responsible for the texture evolution.

Effects of Ultrasonics-Assisted Face Milling on Surface Integrity and Fatigue Life of Ni-Alloy 718

Science.gov (United States)

Suárez, Alfredo; Veiga, Fernando; de Lacalle, Luis N. López; Polvorosa, Roberto; Lutze, Steffen; Wretland, Anders

2016-11-01

This work investigates the effects of ultrasonic vibration-assisted milling on important aspects such us material surface integrity, tool wear, cutting forces and fatigue resistance. As an alternative to natural application of ultrasonic milling in brittle materials, in this study, ultrasonics have been applied to a difficult-to-cut material, Alloy 718, very common in high-temperature applications. Results show alterations in the sub-superficial part of the material which could influence fatigue resistance of the material, as it has been observed in a fatigue test campaign of specimens obtained with the application of ultrasonic milling in comparison with another batch obtained applying conventional milling. Tool wear pattern was found to be very similar for both milling technologies, concluding the study with the analysis of cutting forces, exhibiting certain improvement in case of the application of ultrasonic milling with a more stable evolution.

Controlling chaos-assisted directed transport via quantum resonance.

Science.gov (United States)

Tan, Jintao; Zou, Mingliang; Luo, Yunrong; Hai, Wenhua

2016-06-01

We report on the first demonstration of chaos-assisted directed transport of a quantum particle held in an amplitude-modulated and tilted optical lattice, through a resonance-induced double-mean displacement relating to the true classically chaotic orbits. The transport velocity is controlled by the driving amplitude and the sign of tilt, and also depends on the phase of the initial state. The chaos-assisted transport feature can be verified experimentally by using a source of single atoms to detect the double-mean displacement one by one, and can be extended to different scientific fields.

Controlling chaos-assisted directed transport via quantum resonance

Energy Technology Data Exchange (ETDEWEB)

Tan, Jintao; Zou, Mingliang; Luo, Yunrong; Hai, Wenhua, E-mail: whhai2005@aliyun.com [Department of Physics and Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Normal University, Changsha 410081, China and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha 410081 (China)

2016-06-15

We report on the first demonstration of chaos-assisted directed transport of a quantum particle held in an amplitude-modulated and tilted optical lattice, through a resonance-induced double-mean displacement relating to the true classically chaotic orbits. The transport velocity is controlled by the driving amplitude and the sign of tilt, and also depends on the phase of the initial state. The chaos-assisted transport feature can be verified experimentally by using a source of single atoms to detect the double-mean displacement one by one, and can be extended to different scientific fields.

Patch layout generation by detecting feature networks

KAUST Repository

Cao, Yuanhao; Yan, Dongming; Wonka, Peter

2015-01-01

The patch layout of 3D surfaces reveals the high-level geometric and topological structures. In this paper, we study the patch layout computation by detecting and enclosing feature loops on surfaces. We present a hybrid framework which combines

Design features to reduce occupational exposure

International Nuclear Information System (INIS)

Adam, J.A.; DiSabatino, A.A. Jr.; Vanasse, R.E.

1975-01-01

Some of the design principles which are important considerations in the evolution of a nuclear power plant design to ensure that occupational radiation exposures can be minimized are discussed. Emphasis is placed on the design features affecting the basic layout and equipment locations within the plant. Examples are provided showing how these design objectives are realized in the Stone and Webster Reference Nuclear Power Plant Design, with particular emphasis on the Annulus Building portion of the reference plant. Design features which are useful in reducing occupational exposure during normal operation are discussed initially, followed by those that chiefly affect exposures during maintenance activity. Finally, those provisions in the design which assist in preventing the spread of radioactive contamination are presented

Multi-criteria optimization for ultrasonic-assisted extraction of antioxidants from Pericarpium Citri Reticulatae using response surface methodology, an activity-based approach.

Science.gov (United States)

Zeng, Shanshan; Wang, Lu; Zhang, Lei; Qu, Haibin; Gong, Xingchu

2013-06-01

An activity-based approach to optimize the ultrasonic-assisted extraction of antioxidants from Pericarpium Citri Reticulatae (Chenpi in Chinese) was developed. Response surface optimization based on a quantitative composition-activity relationship model showed the relationships among product chemical composition, antioxidant activity of extract, and parameters of extraction process. Three parameters of ultrasonic-assisted extraction, including the ethanol/water ratio, Chenpi amount, and alkaline amount, were investigated to give optimum extraction conditions for antioxidants of Chenpi: ethanol/water 70:30 v/v, Chenpi amount of 10 g, and alkaline amount of 28 mg. The experimental antioxidant yield under the optimum conditions was found to be 196.5 mg/g Chenpi, and the antioxidant activity was 2023.8 μmol Trolox equivalents/g of the Chenpi powder. The results agreed well with the second-order polynomial regression model. This presented approach promised great application potentials in both food and pharmaceutical industries. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-dimensional measurement of small inner surface profiles using feature-based 3-D panoramic registration

Science.gov (United States)

Gong, Yuanzheng; Seibel, Eric J.

2017-01-01

Rapid development in the performance of sophisticated optical components, digital image sensors, and computer abilities along with decreasing costs has enabled three-dimensional (3-D) optical measurement to replace more traditional methods in manufacturing and quality control. The advantages of 3-D optical measurement, such as noncontact, high accuracy, rapid operation, and the ability for automation, are extremely valuable for inline manufacturing. However, most of the current optical approaches are eligible for exterior instead of internal surfaces of machined parts. A 3-D optical measurement approach is proposed based on machine vision for the 3-D profile measurement of tiny complex internal surfaces, such as internally threaded holes. To capture the full topographic extent (peak to valley) of threads, a side-view commercial rigid scope is used to collect images at known camera positions and orientations. A 3-D point cloud is generated with multiview stereo vision using linear motion of the test piece, which is repeated by a rotation to form additional point clouds. Registration of these point clouds into a complete reconstruction uses a proposed automated feature-based 3-D registration algorithm. The resulting 3-D reconstruction is compared with x-ray computed tomography to validate the feasibility of our proposed method for future robotically driven industrial 3-D inspection.

An actuated force feedback-enabled laparoscopic instrument for robotic-assisted surgery.

Science.gov (United States)

Moradi Dalvand, Mohsen; Shirinzadeh, Bijan; Shamdani, Amir Hossein; Smith, Julian; Zhong, Yongmin

2014-03-01

Robotic-assisted minimally invasive surgery systems not only have the advantages of traditional laparoscopic instruments but also have other important advantages, including restoring the surgeon's hand-eye coordination and improving the surgeon's precision by filtering hand tremors. Unfortunately, these benefits have come at the expense of the surgeon's ability to feel. Various solutions for restoring this feature have been proposed. An actuated modular force feedback-enabled laparoscopic instrument was proposed that is able to measure tip-tissue lateral interaction forces as well as normal grasping forces. The instrument has also the capability to adjust the grasping direction inside the patient body. In order to measure the interaction forces, strain gauges were employed. A series of finite element analyses were performed to gain an understanding of the actual magnitude of surface strains where gauges are applied. The strain gauge bridge configurations were calibrated. A series of experiments was conducted and the results were analysed. The modularity feature of the proposed instrument makes it interchangeable between various tip types of different functionalities (e.g. cutter, grasper, dissector). Calibration results of the strain gauges incorporated into the tube and at the base of the instrument presented the monotonic responses for these strain gauge configurations. Experimental results from tissue probing and tissue characterization experiments verified the capability of the proposed instrument in measuring lateral probing forces and characterizing artificial tissue samples of varying stiffness. The proposed instrument can improve the quality of palpation and characterization of soft tissues of varying stiffness by restoring sense of touch in robotic assisted minimally invasive surgery operations. Copyright © 2013 John Wiley & Sons, Ltd.

SU-D-BRA-04: Computerized Framework for Marker-Less Localization of Anatomical Feature Points in Range Images Based On Differential Geometry Features for Image-Guided Radiation Therapy

International Nuclear Information System (INIS)

Soufi, M; Arimura, H; Toyofuku, F; Nakamura, K; Hirose, T; Umezu, Y; Shioyama, Y

2016-01-01

Purpose: To propose a computerized framework for localization of anatomical feature points on the patient surface in infrared-ray based range images by using differential geometry (curvature) features. Methods: The general concept was to reconstruct the patient surface by using a mathematical modeling technique for the computation of differential geometry features that characterize the local shapes of the patient surfaces. A region of interest (ROI) was firstly extracted based on a template matching technique applied on amplitude (grayscale) images. The extracted ROI was preprocessed for reducing temporal and spatial noises by using Kalman and bilateral filters, respectively. Next, a smooth patient surface was reconstructed by using a non-uniform rational basis spline (NURBS) model. Finally, differential geometry features, i.e. the shape index and curvedness features were computed for localizing the anatomical feature points. The proposed framework was trained for optimizing shape index and curvedness thresholds and tested on range images of an anthropomorphic head phantom. The range images were acquired by an infrared ray-based time-of-flight (TOF) camera. The localization accuracy was evaluated by measuring the mean of minimum Euclidean distances (MMED) between reference (ground truth) points and the feature points localized by the proposed framework. The evaluation was performed for points localized on convex regions (e.g. apex of nose) and concave regions (e.g. nasofacial sulcus). Results: The proposed framework has localized anatomical feature points on convex and concave anatomical landmarks with MMEDs of 1.91±0.50 mm and 3.70±0.92 mm, respectively. A statistically significant difference was obtained between the feature points on the convex and concave regions (P<0.001). Conclusion: Our study has shown the feasibility of differential geometry features for localization of anatomical feature points on the patient surface in range images. The proposed

SU-D-BRA-04: Computerized Framework for Marker-Less Localization of Anatomical Feature Points in Range Images Based On Differential Geometry Features for Image-Guided Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Soufi, M; Arimura, H; Toyofuku, F [Kyushu University, Fukuoka, Fukuoka (Japan); Nakamura, K [Hamamatsu University School of Medicine, Hamamatsu, Shizuoka (Japan); Hirose, T; Umezu, Y [Kyushu University Hospital, Fukuoka, Fukuoka (Japan); Shioyama, Y [Saga Heavy Ion Medical Accelerator in Tosu, Tosu, Saga (Japan)

2016-06-15

Purpose: To propose a computerized framework for localization of anatomical feature points on the patient surface in infrared-ray based range images by using differential geometry (curvature) features. Methods: The general concept was to reconstruct the patient surface by using a mathematical modeling technique for the computation of differential geometry features that characterize the local shapes of the patient surfaces. A region of interest (ROI) was firstly extracted based on a template matching technique applied on amplitude (grayscale) images. The extracted ROI was preprocessed for reducing temporal and spatial noises by using Kalman and bilateral filters, respectively. Next, a smooth patient surface was reconstructed by using a non-uniform rational basis spline (NURBS) model. Finally, differential geometry features, i.e. the shape index and curvedness features were computed for localizing the anatomical feature points. The proposed framework was trained for optimizing shape index and curvedness thresholds and tested on range images of an anthropomorphic head phantom. The range images were acquired by an infrared ray-based time-of-flight (TOF) camera. The localization accuracy was evaluated by measuring the mean of minimum Euclidean distances (MMED) between reference (ground truth) points and the feature points localized by the proposed framework. The evaluation was performed for points localized on convex regions (e.g. apex of nose) and concave regions (e.g. nasofacial sulcus). Results: The proposed framework has localized anatomical feature points on convex and concave anatomical landmarks with MMEDs of 1.91±0.50 mm and 3.70±0.92 mm, respectively. A statistically significant difference was obtained between the feature points on the convex and concave regions (P<0.001). Conclusion: Our study has shown the feasibility of differential geometry features for localization of anatomical feature points on the patient surface in range images. The proposed

Response surface methodology applied to the study of the microwave-assisted synthesis of quaternized chitosan.

Science.gov (United States)

dos Santos, Danilo Martins; Bukzem, Andrea de Lacerda; Campana-Filho, Sérgio Paulo

2016-03-15

A quaternized derivative of chitosan, namely N-(2-hydroxy)-propyl-3-trimethylammonium chitosan chloride (QCh), was synthesized by reacting glycidyltrimethylammonium chloride (GTMAC) and chitosan (Ch) in acid medium under microwave irradiation. Full-factorial 2(3) central composite design and response surface methodology (RSM) were applied to evaluate the effects of molar ratio GTMAC/Ch, reaction time and temperature on the reaction yield, average degree of quaternization (DQ) and intrinsic viscosity ([η]) of QCh. The molar ratio GTMAC/Ch was the most important factor affecting the response variables and RSM results showed that highly substituted QCh (DQ = 71.1%) was produced at high yield (164%) when the reaction was carried out for 30min. at 85°C by using molar ratio GTMAC/Ch 6/1. Results showed that microwave-assisted synthesis is much faster (≤30min.) as compared to conventional reaction procedures (>4h) carried out in similar conditions except for the use of microwave irradiation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Specific features of NH{sub 3} and plasma-assisted MBE in the fabrication of III-N HEMT heterostructures

Energy Technology Data Exchange (ETDEWEB)

Alexeev, A. N. [NTO ZAO (Russian Federation); Krasovitsky, D. M. [Svetlana-Rost ZAO (Russian Federation); Petrov, S. I., E-mail: petrov@semiteq.ru [NTO ZAO (Russian Federation); Chaly, V. P.; Mamaev, V. V. [Svetlana-Rost ZAO (Russian Federation); Sidorov, V. G. [St. Petersburg State Polytechnic University (Russian Federation)

2015-01-15

The specific features of how nitride HEMT heterostructures are produced by NH{sub 3} and plasma-assisted (PA) molecular-beam epitaxy (MBE) are considered. It is shown that the use of high-temperature AlN/AlGaN buffer layers grown with ammonia at extremely high temperatures (up to 1150°C) can drastically improve the structural perfection of the active GaN layers and reduce the dislocation density in these layers to values of 9 × 10{sup 8}−1 × 10{sup 9} cm{sup −2}. The use of buffer layers of this kind makes it possible to obtain high-quality GaN/AlGaN heterostructures by both methods. At the same time, in contrast to ammonia MBE which is difficult to apply at T < 500°C (because of the low efficiency of ammonia decomposition), PA MBE is rather effective at low temperatures, e.g., for the growth of InAlN layers lattice-matched with GaN. The results obtained in the MBE growth of AlN/AlGaN/GaN/InAlN heterostructures by both PA-MBE and NH{sub 3}-MBE with an extremely high ammonia flux are demonstrated.

European Nuclear Features

International Nuclear Information System (INIS)

Barre, B.; Gonzalez, E.; Diaz Diaz, J.L.; Jimenez, J.L.; Velarde, G.; Navarro, J.M.; Hittner, D.; Dominguez, M.T.; Bollini, G.; Martin, A.; Suarez, J.; Traini, E.; Lang-Lenton, J.

2004-01-01

''European Nuclear Features - ENF'' is a joint publication of the three specialized technical journals, Nuclear Espana (Spain), Revue General Nucleaire (France), and atw - International Journal of Nuclear Power (Germany). The ENF support the international Europeen exchange of information and news about energy and nuclear power. News items, comments, and scientific and technical contributions will cover important aspects of the field. The second issue of ENF contains contributions about theses topics, among others: Institutional and Political Changes in the EU. - CIEMAT Department of Nuclear Fission: A General Overview. - Inertial Fusion Energy at DENIM. - High Temperature Reactors. European Research Programme. - On Site Assistance to Khmelnitsky NPP 1 and 2 (Ukraine). - Dismantling and Decommissioning of Vandellos I. (orig.)

Influence of trap-assisted tunneling on trap-assisted tunneling current in double gate tunnel field-effect transistor

International Nuclear Information System (INIS)

Jiang Zhi; Zhuang Yi-Qi; Li Cong; Wang Ping; Liu Yu-Qi

2016-01-01

Trap-assisted tunneling (TAT) has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor (TFET). In this paper, we assess subthreshold performance of double gate TFET (DG-TFET) through a band-to-band tunneling (BTBT) model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile (D it ) and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current. (paper)

Specific Features of Chip Making and Work-piece Surface Layer Formation in Machining Thermal Coatings

Directory of Open Access Journals (Sweden)

V. M. Yaroslavtsev

2016-01-01

Full Text Available A wide range of unique engineering structural and performance properties inherent in metallic composites characterizes wear- and erosion-resistant high-temperature coatings made by thermal spraying methods. This allows their use both in manufacturing processes to enhance the wear strength of products, which have to operate under the cyclic loading, high contact pressures, corrosion and high temperatures and in product renewal.Thermal coatings contribute to the qualitative improvement of the technical level of production and product restoration using the ceramic composite materials. However, the possibility to have a significantly increased product performance, reduce their factory labour hours and materials/output ratio in manufacturing and restoration is largely dependent on the degree of the surface layer quality of products at their finishing stage, which is usually provided by different kinds of machining.When machining the plasma-sprayed thermal coatings, a removing process of the cut-off layer material is determined by its distinctive features such as a layered structure, high internal stresses, low ductility material, high tendency to the surface layer strengthening and rehardening, porosity, high abrasive properties, etc. When coatings are machined these coating properties result in specific characteristics of chip formation and conditions for formation of the billet surface layer.The chip formation of plasma-sprayed coatings was studied at micro-velocities using an experimental tool-setting microscope-based setup, created in BMSTU. The setup allowed simultaneous recording both the individual stages (phases of the chip formation process and the operating force factors.It is found that formation of individual chip elements comes with the multiple micro-cracks that cause chipping-off the small particles of material. The emerging main crack in the cut-off layer of material leads to separation of the largest chip element. Then all the stages

Antibacterial Surface Design of Titanium-Based Biomaterials for Enhanced Bacteria-Killing and Cell-Assisting Functions Against Periprosthetic Joint Infection.

Science.gov (United States)

Wang, Jiaxing; Li, Jinhua; Qian, Shi; Guo, Geyong; Wang, Qiaojie; Tang, Jin; Shen, Hao; Liu, Xuanyong; Zhang, Xianlong; Chu, Paul K

2016-05-04

Periprosthetic joint infection (PJI) is one of the formidable and recalcitrant complications after orthopedic surgery, and inhibiting biofilm formation on the implant surface is considered crucial to prophylaxis of PJI. However, it has recently been demonstrated that free-floating biofilm-like aggregates in the local body fluid and bacterial colonization on the implant and peri-implant tissues can coexist and are involved in the pathogenesis of PJI. An effective surface with both contact-killing and release-killing antimicrobial capabilities can potentially abate these concerns and minimize PJI caused by adherent/planktonic bacteria. Herein, Ag nanoparticles (NPs) are embedded in titania (TiO2) nanotubes by anodic oxidation and plasma immersion ion implantation (PIII) to form a contact-killing surface. Vancomycin is then incorporated into the nanotubes by vacuum extraction and lyophilization to produce the release-killing effect. A novel clinical PJI model system involving both in vitro and in vivo use of methicillin-resistant Staphylococcus aureus (MRSA) ST239 is established to systematically evaluate the antibacterial properties of the hybrid surface against planktonic and sessile bacteria. The vancomycin-loaded and Ag-implanted TiO2 nanotubular surface exhibits excellent antimicrobial and antibiofilm effects against planktonic/adherent bacteria without appreciable silver ion release. The fibroblasts/bacteria cocultures reveal that the surface can help fibroblasts to combat bacteria. We first utilize the nanoarchitecture of implant surface as a bridge between the inorganic bactericide (Ag NPs) and organic antibacterial agent (vancomycin) to achieve total victory in the battle of PJI. The combination of contact-killing and release-killing together with cell-assisting function also provides a novel and effective strategy to mitigate bacterial infection and biofilm formation on biomaterials and has large potential in orthopedic applications.

Surface decontamination

International Nuclear Information System (INIS)

Silva, S. da; Teixeira, M.V.

1986-06-01

The general methods of surface decontamination used in laboratory and others nuclear installations areas, as well as the procedures for handling radioactive materials and surfaces of work are presented. Some methods for decontamination of body external parts are mentioned. The medical supervision and assistance are required for internal or external contamination involving or not lesion in persons. From this medical radiation protection decontamination procedures are determined. (M.C.K.) [pt

Rules and economic features connected with adoption and medical assisted reproduction

Directory of Open Access Journals (Sweden)

Hemion Braho

2015-07-01

Full Text Available The aim of this brief study is to analyze the phenomenon of adoption and the assisted reproductive technologies, not from a social point of view as experts often do, but on an economic point of view. This could be possible analyzing first of all the laws regulating these “markets” and the influence of this regulation on the economic aspects. Although it could seem immoral to study this social aspects connected with filiation, we know that the social desire of some parents or some individuals to have children and their possibility is oriented by laws, economic possibilities and economy in general. This study is based on an empirical methodology, taking as study-case Italy and trying not to give any ethic orientation.

Surface assisted electric transport in Ag2S thin films

International Nuclear Information System (INIS)

Karashanova, D.; Starbov, N.

2006-01-01

Electric transport measurements of thickness-dependent electronic and ionic conductivity of epitaxial Ag 2 S films are used to split both kinds of conductivity into bulk and surface components. The established considerable electronic and ionic surface conductances demonstrate unambiguously the co-existance of electronic and ionic space charge regions in the vicinity of silver sulfide free surface oriented along the zone axes [1-bar 01-bar ]. The parameters of both space charge layers - surface potential, thickness of the space charge region and concentration of the surface compensating charges, are calculated. It is estimated that for intrinsic silver sulfide, the effective surface potential of (1-bar 01-bar ) Ag 2 S surface is negative, its value being about -610mV at 400K

East Chestnut Ridge hydrogeologic characterization: A geophysical study of two karst features

International Nuclear Information System (INIS)

1991-01-01

Permitting and site selection activities for the proposed East Chestnut Ridge landfill, located on the Oak Ridge Reservation, have required additional hydrogeologic studies of two karst features. Geophysical testing methods were utilized for investigating these karst features. The objectives of the geophysical testing was to determine the feasibility of geophysical techniques for locating subsurface karst features and to determine if subsurface anomalies exist at the proposed landfill site. Two karst features, one lacking surface expression (sinkhole) but with a known solution cavity at depth (from previous hydrologic studies), and the other with surface expression were tested with surface geophysical methods. Four geophysical profiles, two crossing and centered over each karst feature were collected using both gravimetric and electrical resistivity techniques

i-Car: An Intelligent and Interactive Interface for Driver Assistance ...

African Journals Online (AJOL)

i-Car: An Intelligent and Interactive Interface for Driver Assistance System. ... techniques with pattern recognition, feature extraction, machine learning, object recognition, ... The system uses eye closure based decision algorithm to detect driver ...

Carabelli's trait revisited: an examination of mesiolingual features at the enamel-dentine junction and enamel surface of Pan and Homo sapiens upper molars.

Science.gov (United States)

Ortiz, Alejandra; Skinner, Matthew M; Bailey, Shara E; Hublin, Jean-Jacques

2012-10-01

Carabelli's trait is a morphological feature that frequently occurs on the mesiolingual aspect of Homo sapiens upper molars. Similar structures also referred to as Carabelli's trait have been reported in apes and fossil hominins. However, the morphological development and homology of these mesiolingual structures among hominoids are poorly understood. In this study, we employ micro-computed tomography to image the enamel-dentine junction (EDJ) and outer enamel surface (OES) of Pan (n = 48) and H. sapiens (n = 52) upper molars. We investigate the developmental origin of mesiolingual features in these taxa and establish the relative contribution of the EDJ and enamel cap to feature expression. Results demonstrate that mesiolingual features of H. sapiens molars develop at the EDJ and are similarly expressed at the OES. Morphological variation at both surfaces in this taxon can satisfactorily be assessed using standards for Carabelli's trait developed by the Arizona State University Dental Anthropology System (ASUDAS). Relative to H. sapiens, Pan has an even greater degree of correspondence in feature expression between the EDJ and OES. Morphological manifestations in Pan molars are not necessarily limited to the protocone and are best characterized by a lingual cingulum that cannot be captured by the ASUDAS. Cusp-like structures, similar to those seen in marked Carabelli's trait expressions in H. sapiens, were not found in Pan. This study provides a foundation for further analyses on the evolutionary history of mesiolingual dental traits within the hominoid lineage. It also highlights the wealth of morphological data that can be obtained at the EDJ for understanding tooth development and for characterizing tooth crown variation in worn fossil teeth. Copyright © 2012 Elsevier Ltd. All rights reserved.

Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from the Flower of Jatropha integerrima by Response Surface Methodology.

Science.gov (United States)

Xu, Dong-Ping; Zhou, Yue; Zheng, Jie; Li, Sha; Li, An-Na; Li, Hua-Bin

2015-12-24

An ultrasound-assisted extraction (UAE) method was developed for the efficient extraction of natural antioxidants from the flowers of Jatropha integerrima. Four independent variables, including ethanol concentration, solvent/material ratio, ultrasound irradiation time and temperature were studied by single factor experiments. Then, the central composite rotatable design and response surface methodology were employed to investigate the effect of three key parameters (ethanol concentration, solvent/material ratio, and ultrasound irradiation time) on the antioxidant activities of the flower extracts. The optimal extraction conditions were an ethanol concentration of 59.6%, solvent/material ratio of 50:1, ultrasound irradiation time of 7 min, and ultrasound irradiation temperature of 40 °C. Under these conditions, the optimized experimental value was 1103.38 ± 16.11 µmol Trolox/g dry weight (DW), which was in accordance with the predicted value (1105.49 µmol Trolox/g DW). Furthermore, the antioxidant activities of flower extracts obtained by UAE were compared with those produced by the traditional maceration and Soxhlet extraction methods, and UAE resulted in higher antioxidant activities after a shorter time at a lower temperature. The results obtained are helpful for the full utilization of Jatropha integerrima, and also indicate that ultrasound-assisted extraction is an efficient method for the extraction of natural antioxidants from plant materials.

Optimization of Ultrasound-Assisted Extraction of Natural Antioxidants from the Flower of Jatropha integerrima by Response Surface Methodology

Directory of Open Access Journals (Sweden)

Dong-Ping Xu

2015-12-01

Full Text Available An ultrasound-assisted extraction (UAE method was developed for the efficient extraction of natural antioxidants from the flowers of Jatropha integerrima. Four independent variables, including ethanol concentration, solvent/material ratio, ultrasound irradiation time and temperature were studied by single factor experiments. Then, the central composite rotatable design and response surface methodology were employed to investigate the effect of three key parameters (ethanol concentration, solvent/material ratio, and ultrasound irradiation time on the antioxidant activities of the flower extracts. The optimal extraction conditions were an ethanol concentration of 59.6%, solvent/material ratio of 50:1, ultrasound irradiation time of 7 min, and ultrasound irradiation temperature of 40 °C. Under these conditions, the optimized experimental value was 1103.38 ± 16.11 µmol Trolox/g dry weight (DW, which was in accordance with the predicted value (1105.49 µmol Trolox/g DW. Furthermore, the antioxidant activities of flower extracts obtained by UAE were compared with those produced by the traditional maceration and Soxhlet extraction methods, and UAE resulted in higher antioxidant activities after a shorter time at a lower temperature. The results obtained are helpful for the full utilization of Jatropha integerrima, and also indicate that ultrasound-assisted extraction is an efficient method for the extraction of natural antioxidants from plant materials.

Efficient Feature-Driven Visualization of Large-Scale Scientific Data

Energy Technology Data Exchange (ETDEWEB)

Lu, Aidong

2012-12-12

Very large, complex scientific data acquired in many research areas creates critical challenges for scientists to understand, analyze, and organize their data. The objective of this project is to expand the feature extraction and analysis capabilities to develop powerful and accurate visualization tools that can assist domain scientists with their requirements in multiple phases of scientific discovery. We have recently developed several feature-driven visualization methods for extracting different data characteristics of volumetric datasets. Our results verify the hypothesis in the proposal and will be used to develop additional prototype systems.

Notes on photon assisted field ionization

International Nuclear Information System (INIS)

Niu, B.H.C.; Bryant, P.J.

1979-01-01

A response to comments by Viswanathan et al (2) on a previous publication(1) by the authors is given. It is contended that the original hypothesis of photon assisted field ionization at metal surfaces correctly explains the results reported in Ref. 1

Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

Energy Technology Data Exchange (ETDEWEB)

Razavizadeh, Mahmoud; Jamshidi, Masoud, E-mail: mjamshidi@iust.ac.ir

2016-08-30

Highlights: • In this research UV-irradiated PET fabric was chemically modified. • The fabric at first carboxylated under UV irradiation using glutaric anhydride, then it was grafted using isocyanate (i.e. MDI). • The surface of the fabric was characterized before and after each treating satge. • The composite samples were prepared and tested for T-Peel test. The surfaces of the fabrics were surface characterized to understand. - Abstract: Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

International Nuclear Information System (INIS)

Razavizadeh, Mahmoud; Jamshidi, Masoud

2016-01-01

Highlights: • In this research UV-irradiated PET fabric was chemically modified. • The fabric at first carboxylated under UV irradiation using glutaric anhydride, then it was grafted using isocyanate (i.e. MDI). • The surface of the fabric was characterized before and after each treating satge. • The composite samples were prepared and tested for T-Peel test. The surfaces of the fabrics were surface characterized to understand. - Abstract: Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

Nanopatterned surface with adjustable area coverage and feature size fabricated by photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Bai Yang; Zhang Yan; Li Wei; Zhou Xuefeng; Wang Changsong; Feng Xin [State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009 (China); Zhang Luzheng [Petroleum Research Recovery Center, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Lu Xiaohua, E-mail: xhlu@njut.edu.cn [State Key Laboratory of Materials-oriented Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009 (China)

2009-08-30

We report an effective approach to fabricate nanopatterns of alkylsilane self-assembly monolayers (SAMs) with desirable coverage and feature size by gradient photocatalysis in TiO{sub 2} aqueous suspension. Growth and photocatalytic degradation of octadecyltrichlorosilane (OTS) were combined to fabricate adjustable monolayered nanopatterns on mica sheet in this work. Systematic atomic force microscopy (AFM) analysis showed that OTS-SAMs that have similar area coverage with different feature sizes and similar feature size with different area coverages can be fabricated by this approach. Contact angle measurement was applied to confirm the gradually varied nanopatterns contributed to the gradient of UV light illumination. Since this approach is feasible for various organic SAMs and substrates, a versatile method was presented to prepare tunable nanopatterns with desirable area coverage and feature size in many applications, such as molecular and biomolecular recognition, sensor and electrode modification.

Nanopatterned surface with adjustable area coverage and feature size fabricated by photocatalysis

International Nuclear Information System (INIS)

Bai Yang; Zhang Yan; Li Wei; Zhou Xuefeng; Wang Changsong; Feng Xin; Zhang Luzheng; Lu Xiaohua

2009-01-01

We report an effective approach to fabricate nanopatterns of alkylsilane self-assembly monolayers (SAMs) with desirable coverage and feature size by gradient photocatalysis in TiO 2 aqueous suspension. Growth and photocatalytic degradation of octadecyltrichlorosilane (OTS) were combined to fabricate adjustable monolayered nanopatterns on mica sheet in this work. Systematic atomic force microscopy (AFM) analysis showed that OTS-SAMs that have similar area coverage with different feature sizes and similar feature size with different area coverages can be fabricated by this approach. Contact angle measurement was applied to confirm the gradually varied nanopatterns contributed to the gradient of UV light illumination. Since this approach is feasible for various organic SAMs and substrates, a versatile method was presented to prepare tunable nanopatterns with desirable area coverage and feature size in many applications, such as molecular and biomolecular recognition, sensor and electrode modification.

Tailoring the surface properties of polypropylene films through cold atmospheric pressure plasma (CAPP) assisted polymerization and immobilization of biomolecules for enhancement of anti-coagulation activity

International Nuclear Information System (INIS)

Navaneetha Pandiyaraj, K.; Ram Kumar, M.C.; Arun Kumar, A.; Padmanabhan, P.V.A.; Deshmukh, R.R.; Bah, M.; Ismat Shah, S.; Su, Pi-Guey; Halleluyah, M.; Halim, A.S.

2016-01-01

Graphical abstract: - Highlights: • Developed low cost cold atmospheric plasma reactor for plasma polymerization technique. • Surface of the PP film was modified by grafting of AAc and PEG by CAPP polymerization. • Biomolecules of chitosan, insulin and heparin were immobilized on surface of PEG-AAc grafted PP films. • The surface modified PP films were characterized by various techniques. • The plasma polymerized and immobilized film reveals substantial blood compatibility. - Abstract: Enhancement of anti-thrombogenic properties of polypropylene (PP) to avert the adsorption of plasma proteins (fibrinogen and albumin), adhesion and activation of the platelets are very important for vast biomedical applications. The cold atmospheric pressure plasma (CAPP) assisted polymerization has potential to create the specific functional groups such as O−C=O, C=O, C−N and S−S. on the surface of polymeric films using selective precursor in vapour phase to enhance anti-thrombogenic properties. Such functionalized polymeric surfaces would be suitable for various biomedical applications especially to improve the blood compatibility. The eventual aspiration of the present investigation is to develop the biofunctional coating onto the surface of PP films using acrylic acid (AAc) and polyethylene glycol (PEG) as a precursor in a vapour phase by incorporating specific functional groups for immobilization of biomolecules such as heparin (HEP), chitosan (CHI) and insulin (INS) on the surface of plasma modified PP films. The surface properties such as hydrophilicity, chemical composition, surface topography of the surface modified PP films were analyzed by contact angle (CA), Fourier transform infrared spectroscopy (FTIR), X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM). Furthermore the anti-thrombogenic properties of the surface modified PP films were studied by in vitro tests which include platelet adhesion and protein adsorption analysis. It was

Tailoring the surface properties of polypropylene films through cold atmospheric pressure plasma (CAPP) assisted polymerization and immobilization of biomolecules for enhancement of anti-coagulation activity

Energy Technology Data Exchange (ETDEWEB)

Navaneetha Pandiyaraj, K., E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T By Pass, Chinniyam Palayam (Post), Coimbatore 641062 (India); Ram Kumar, M.C.; Arun Kumar, A. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L& T By Pass, Chinniyam Palayam (Post), Coimbatore 641062 (India); Padmanabhan, P.V.A. [PSN College of Engineering and Technology, Tirunelveli 627 152 (India); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Bah, M.; Ismat Shah, S. [Department of Physics and Astronomy, Department of Materials Science and Engineering, University of Delaware, 208 Dupont Hall, Newark (United States); Su, Pi-Guey [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Halleluyah, M.; Halim, A.S. [School of Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

2016-05-01

Graphical abstract: - Highlights: • Developed low cost cold atmospheric plasma reactor for plasma polymerization technique. • Surface of the PP film was modified by grafting of AAc and PEG by CAPP polymerization. • Biomolecules of chitosan, insulin and heparin were immobilized on surface of PEG-AAc grafted PP films. • The surface modified PP films were characterized by various techniques. • The plasma polymerized and immobilized film reveals substantial blood compatibility. - Abstract: Enhancement of anti-thrombogenic properties of polypropylene (PP) to avert the adsorption of plasma proteins (fibrinogen and albumin), adhesion and activation of the platelets are very important for vast biomedical applications. The cold atmospheric pressure plasma (CAPP) assisted polymerization has potential to create the specific functional groups such as O−C=O, C=O, C−N and S−S. on the surface of polymeric films using selective precursor in vapour phase to enhance anti-thrombogenic properties. Such functionalized polymeric surfaces would be suitable for various biomedical applications especially to improve the blood compatibility. The eventual aspiration of the present investigation is to develop the biofunctional coating onto the surface of PP films using acrylic acid (AAc) and polyethylene glycol (PEG) as a precursor in a vapour phase by incorporating specific functional groups for immobilization of biomolecules such as heparin (HEP), chitosan (CHI) and insulin (INS) on the surface of plasma modified PP films. The surface properties such as hydrophilicity, chemical composition, surface topography of the surface modified PP films were analyzed by contact angle (CA), Fourier transform infrared spectroscopy (FTIR), X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM). Furthermore the anti-thrombogenic properties of the surface modified PP films were studied by in vitro tests which include platelet adhesion and protein adsorption analysis. It was

Unoccupied surface electronic structure of Gd(0001)

International Nuclear Information System (INIS)

Li, D.; Dowben, P.A.; Ortega, J.E.; Himpsel, F.J.

1994-01-01

The unoccupied surface electronic structure of Gd(0001) was investigated with high-resolution inverse-photoemission spectroscopy. An empty surface state near E F is observed at bar Γ. Two other surface-sensitive features are also revealed at 1.2 and 3.1 eV above the Fermi level. Hydrogen adsorption on Gd surfaces was used to distinguish the surface-sensitive features from the bulk features. The unoccupied bulk-band critical points are determined to be Γ 3 + at 1.9 eV and A 1 at 0.8 eV

Alkali-crown ether complexes at metal surfaces

Energy Technology Data Exchange (ETDEWEB)

Thontasen, Nicha; Deng, Zhitao; Rauschenbach, Stephan [Max Planck Institute for Solid State Research, Stuttgart (Germany); Levita, Giacomo [University of Trieste, Trieste (Italy); Malinowski, Nikola [Max Planck Institute for Solid State Research, Stuttgart (Germany); Bulgarian Academy of Sciences, Sofia (Bulgaria); Kern, Klaus [Max Planck Institute for Solid State Research, Stuttgart (Germany); EPFL, Lausanne (Switzerland)

2010-07-01

Crown ethers are polycyclic ethers which, in solution, selectively bind cations depending on the size of the ring cavity. The study of a single host-guest complex is highly desirable in order to reveal the characteristics of these specific interactions at the atomic scale. Such detailed investigation is possible at the surface where high resolution imaging tools like scanning tunneling microscopy (STM) can be applied. Here, electrospray ion beam deposition (ES-IBD) is employed for the deposition of Dibenzo-24-crown-8 (DB24C8)-H{sup +}, -Na{sup +} and -Cs{sup +} complexes on a solid surface in ultrahigh vacuum (UHV). Where other deposition techniques have not been successful, this deposition technique combines the advantages of solution based preparation of the complex ions with a highly clean and controlled deposition in UHV. Single molecular structures and the cation-binding of DB24C8 at the surface are studied in situ by STM and MALDI-MS (matrix assisted laser desorption ionization mass spectrometry). The internal structure of the complex, i.e. ring and cavity, is observable only when alkali cations are incorporated. The BD24C8-H{sup +} complex in contrast appears as a compact feature. This result is in good agreement with theoretical models based on density functional theory calculations.

Determination of trace quaternary ammonium surfactants in water by combining solid-phase extraction with surface-assisted laser desorption/ionization mass spectrometry.

Science.gov (United States)

Chen, Y C; Sun, M C

2001-01-01

This study demonstrates the feasibility of combining solid-phase extraction (SPE) with surface-assisted laser desorption/ionization (SALDI) mass spectrometry to determine trace quaternary ammonium surfactants in water. The trace surfactants in water were directly concentrated on the surface of activated carbon sorbent in SPE. The activated carbon sorbent was then mixed with the SALDI liquid for SALDI analysis. No SPE elution procedure was necessary. Experimental results indicate that the surfactants with longer chain alkyl groups exhibit higher sensitivities than those with shorter chain alkyl groups in SPE-SALDI analysis. The detection limit for hexadecyltrimethylammonium bromide is around 10 ppt in SPE-SALDI analysis by sampling 100 mL of aqueous solution, while that of tetradecyltrimethylammonium bromide is about 100 ppt. The detection limit for decyltrimethylammonium bromide and dodecyltrimethylammonium bromide is in the low-ppb range. Copyright 2001 John Wiley & Sons, Ltd.

Feature curve extraction from point clouds via developable strip intersection

Directory of Open Access Journals (Sweden)

Kai Wah Lee

2016-04-01

Full Text Available In this paper, we study the problem of computing smooth feature curves from CAD type point clouds models. The proposed method reconstructs feature curves from the intersections of developable strip pairs which approximate the regions along both sides of the features. The generation of developable surfaces is based on a linear approximation of the given point cloud through a variational shape approximation approach. A line segment sequencing algorithm is proposed for collecting feature line segments into different feature sequences as well as sequential groups of data points. A developable surface approximation procedure is employed to refine incident approximation planes of data points into developable strips. Some experimental results are included to demonstrate the performance of the proposed method.

Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

Science.gov (United States)

Razavizadeh, Mahmoud; Jamshidi, Masoud

2016-08-01

Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

Surface phase separation, dewetting feature size, and crystal morphology in thin films of polystyrene/poly(ε-caprolactone) blend.

Science.gov (United States)

Ma, Meng; He, Zhoukun; Li, Yuhan; Chen, Feng; Wang, Ke; Zhang, Qing; Deng, Hua; Fu, Qiang

2012-12-01

Thin films of polystyrene (PS)/poly(ε-caprolactone) (PCL) blends were prepared by spin-coating and characterized by tapping mode force microscopy (AFM). Effects of the relative concentration of PS in polymer solution on the surface phase separation and dewetting feature size of the blend films were systematically studied. Due to the coupling of phase separation, dewetting, and crystallization of the blend films with the evaporation of solvent during spin-coating, different size of PS islands decorated with various PCL crystal structures including spherulite-like, flat-on individual lamellae, and flat-on dendritic crystal were obtained in the blend films by changing the film composition. The average distance of PS islands was shown to increase with the relative concentration of PS in casting solution. For a given ratio of PS/PCL, the feature size of PS appeared to increase linearly with the square of PS concentration while the PCL concentration only determined the crystal morphology of the blend films with no influence on the upper PS domain features. This is explained in terms of vertical phase separation and spinodal dewetting of the PS rich layer from the underlying PCL rich layer, leading to the upper PS dewetting process and the underlying PCL crystalline process to be mutually independent. Copyright © 2012 Elsevier Inc. All rights reserved.

Parabolic features and the erosion rate on Venus

Science.gov (United States)

Strom, Robert G.

1993-01-01

The impact cratering record on Venus consists of 919 craters covering 98 percent of the surface. These craters are remarkably well preserved, and most show pristine structures including fresh ejecta blankets. Only 35 craters (3.8 percent) have had their ejecta blankets embayed by lava and most of these occur in the Atla-Beta Regio region; an area thought to be recently active. parabolic features are associated with 66 of the 919 craters. These craters range in size from 6 to 105 km diameter. The parabolic features are thought to be the result of the deposition of fine-grained ejecta by winds in the dense venusian atmosphere. The deposits cover about 9 percent of the surface and none appear to be embayed by younger volcanic materials. However, there appears to be a paucity of these deposits in the Atla-Beta Regio region, and this may be due to the more recent volcanism in this area of Venus. Since parabolic features are probably fine-grain, wind-deposited ejecta, then all impact craters on Venus probably had these deposits at some time in the past. The older deposits have probably been either eroded or buried by eolian processes. Therefore, the present population of these features is probably associated with the most recent impact craters on the planet. Furthermore, the size/frequency distribution of craters with parabolic features is virtually identical to that of the total crater population. This suggests that there has been little loss of small parabolic features compared to large ones, otherwise there should be a significant and systematic paucity of craters with parabolic features with decreasing size compared to the total crater population. Whatever is erasing the parabolic features apparently does so uniformly regardless of the areal extent of the deposit. The lifetime of parabolic features and the eolian erosion rate on Venus can be estimated from the average age of the surface and the present population of parabolic features.

Sphingomonads in Microbe-Assisted Phytoremediation: Tackling Soil Pollution.

Science.gov (United States)

Gatheru Waigi, Michael; Sun, Kai; Gao, Yanzheng

2017-09-01

Soil pollution has become a major concern in various terrestrial ecosystems worldwide. One in situ soil bioremediation strategy that has gained popularity recently is microbe-assisted phytoremediation, which is promising for remediating pollutants. Sphingomonads, a versatile bacteria group comprising four well-known genera, are ubiquitous in vegetation grown in contaminated soils. These Gram-negative microbes have been investigated for their ability to induce innate plant growth-promoting (PGP) traits, including the formation of phytohormones, siderophores, and chelators, in addition to their evolutionary adaptations enabling biodegradation and microbe-assisted removal of contaminants. However, their capacity for bacterial-assisted phytoremediation has to date been undervalued. Here, we highlight the specific features, roles, advantages, and challenges associated with using sphingomonads in plant-microbe interactions, from the perspective of future phytotechnologies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microwave-Assisted Extraction of Cannabinoids in Hemp Nut Using Response Surface Methodology: Optimization and Comparative Study

Directory of Open Access Journals (Sweden)

Chih-Wei Chang

2017-11-01

Full Text Available Hemp nut is commonly incorporated into several food preparations; however, most countries set regulations for hemp products according to their cannabinoid content. In this study, we have developed an efficient microwave-assisted extraction (MAE method for cannabinoids (i.e., Δ9-tetrahydrocannabinol, cannabidiol, and cannabinol in hemp nut. Optimization of the MAE procedure was conducted through single factor experiments and response surface methodology (RSM. A comparative study was also conducted to determine the differences in the extraction yields and morphology of hemp nut between MAE and reference extraction methods, namely heat reflux extraction (HRE, Soxhlet extraction (SE, supercritical fluid extraction (SFE, and ultrasound-assisted extraction (UAE. Among the independent variables in RSM, the temperature was the most significant parameter. The optimal conditions of MAE were as follows: extraction solvent of methanol, microwave power of 375 W, temperature of 109 °C, and extraction time of 30 min. Compared with reference extraction methods, MAE achieved the highest extraction yields of total cannabinoids in hemp nut (6.09 μg/g for MAE; 4.15 μg/g for HRE; 5.81 μg/g for SE; 3.61 μg/g for SFE; 3.73 μg/g for UAE with the least solvent consumption and shortest time. Morphological observations showed that substantial cell rupturing occurred in the microstructure of hemp nut after MAE, indicating enhanced dissolution of the target compounds during the extraction process. The MAE method is thus a rapid, economic, and environmentally friendly extraction method that is both effective and practical for industrial applications.

Experimental investigation on low-frequency vibration assisted micro-WEDM of Inconel 718

Directory of Open Access Journals (Sweden)

Deepak Rajendra Unune

2017-02-01

Full Text Available The micro-wire electric discharge machining (micro-WEDM has emerged as the popular micromachining processes for fabrication of micro-features. However, the low machining rate and poor surface finish are restricting wide applications of this process. Therefore, in this study, an attempt was made to improve machining rate of micro-WEDM with low-frequency workpiece vibration assistance. The gap voltage, capacitance, feed rate and vibrational frequency were chosen as control factors, whereas, the material removal rate (MRR and kerf width were selected as performance measures while fabricating microchannels in Inconel 718. It was observed that in micro-WEDM, the capacitance is the most significant factor affecting both MRR and kerf width. It was witnessed that the low-frequency workpiece vibration improves the performance of micro-WEDM by improving the MRR due to enhanced flushing conditions and reduced electrode-workpiece adhesion.

Optimization of ultrasound-assisted extraction to obtain mycosterols from Agaricus bisporus L. by response surface methodology and comparison with conventional Soxhlet extraction.

Science.gov (United States)

Heleno, Sandrina A; Diz, Patrícia; Prieto, M A; Barros, Lillian; Rodrigues, Alírio; Barreiro, Maria Filomena; Ferreira, Isabel C F R

2016-04-15

Ergosterol, a molecule with high commercial value, is the most abundant mycosterol in Agaricus bisporus L. To replace common conventional extraction techniques (e.g. Soxhlet), the present study reports the optimal ultrasound-assisted extraction conditions for ergosterol. After preliminary tests, the results showed that solvents, time and ultrasound power altered the extraction efficiency. Using response surface methodology, models were developed to investigate the favourable experimental conditions that maximize the extraction efficiency. All statistical criteria demonstrated the validity of the proposed models. Overall, ultrasound-assisted extraction with ethanol at 375 W during 15 min proved to be as efficient as the Soxhlet extraction, yielding 671.5 ± 0.5mg ergosterol/100 g dw. However, with n-hexane extracts with higher purity (mg ergosterol/g extract) were obtained. Finally, it was proposed for the removal of the saponification step, which simplifies the extraction process and makes it more feasible for its industrial transference. Copyright © 2015 Elsevier Ltd. All rights reserved.

Differential clinical features and stool findings in shigellosis and amoebic dysentery

NARCIS (Netherlands)

Speelman, P.; McGlaughlin, R.; Kabir, I.; Butler, T.

1987-01-01

To obtain information that could assist the clinician to differentiate between shigellosis and amoebic dysentery, we compared clinical features and stool findings in 58 adult male patients in Bangladesh. Mean values indicated that patients with invasive amoebiasis were older and had a longer

Surface-Assisted Self-Assembly Strategies Leading to Supramolecular Hydrogels.

Science.gov (United States)

Vigier-Carrière, Cécile; Boulmedais, Fouzia; Schaaf, Pierre; Jierry, Loïc

2018-02-05

Localized molecular self-assembly processes leading to the growth of nanostructures exclusively from the surface of a material is one of the great challenges in surface chemistry. In the last decade, several works have been reported on the ability of modified or unmodified surfaces to manage the self-assembly of low-molecular-weight hydrogelators (LMWH) resulting in localized supramolecular hydrogel coatings mainly based on nanofiber architectures. This Minireview highlights all strategies that have emerged recently to initiate and localize LMWH supramolecular hydrogel formation, their related fundamental issues and applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of microstructure and surface features on wetting angle of a Fe-3.2 wt%C.E. cast iron with water

Science.gov (United States)

Riahi, Samira; Niroumand, Behzad; Dorri Moghadam, Afsaneh; Rohatgi, Pradeep K.

2018-05-01

In the present study, variation in surface wetting behavior of a hypoeutectic cast iron with its microstructural features and surface roughness was investigated. Samples with an identical composition, i.e. Fe-3.2 wt%C.E., and different microstructures (a gray cast iron with A-type flake graphite and a white cast iron) were fabricated by gravity casting of molten cast iron in a chill mold at different cooling rates. A variation of surface roughness was also developed by polishing, a four-stage electroetching and a four-stage mechanical abrading on the samples. Roughness and water contact angles of all surfaces were then measured. The surface roughness factor and the solid fraction in contact with water by the Wenzel and Cassie-Baxter contact models were also calculated and compared with the corresponding measured contact angles to find out which regime was active. Results indicated that the surface microstructure and the type of constituents present at the surface influenced the cast iron surface wettability and that it was possible to change the surface contact angle by modification of the surface microstructure. The mechanically abraded gray cast iron followed the Wenzel-type regime while the electroetched surfaces of gray cast iron exhibited a transition from Wenzel to Cassie-Baxter type regime. In white cast iron, the results indicated Wenzel type behavior in the electroetched samples while for the mechanically abraded samples, none of these two models could predict the wetting behavior. Furthermore, the wetting angles of both gray and white cast irons were measured after 1, 2, 3 and 4 weeks of air exposure. The results showed that the wetting angles of both samples increased to above 90° after one week of air exposure which was likely due to adsorption of low surface energy hydrocarbons on the surfaces.

Ion beams application to modification of surface layer of solids with particular regard to IBAD method - ion beam assisted deposition realized in the INP; Zastosowanie wiazek jonowych do modyfikowania warstwy wierzchniej cial stalych, ze szczegolnym uwzglednieniem metody IBAD - Ion Beam Assisted Deposition, realizowanej w IFJ

Energy Technology Data Exchange (ETDEWEB)

Drwiega, M.; Lipinska, E.

1992-12-31

The different trends in ion engineering such as: dynamic ion mixing, ionized cluster beam deposition and ion beam assisted deposition are described. Some examples of properties of surface coatings are given and their applications are presented. The future of ion engineering is described. 48 refs, 12 figs, 4 tabs.

Molecular dynamics study of the effect of substrate temperature and Ar ion assisted deposition on the deposition of amorphous TiO_2 films

International Nuclear Information System (INIS)

Chen, Xian; Zhang, Jing; Zhao, Yu-Qing

2017-01-01

Highlights: • The surface roughness of a-TiO_2 films is decreased with the increment of the Ar ion assisted energy. • The surface roughness of a-TiO_2 films is decreased with higher substrate temperature when the substrate has an island structure. • The assisted Ar ion has power of making a flat surface and increasing the local temperature. • The assisted Ar ion will influence the growth mode with the change of surface atom mobility. • The Volmer-Weber (island) growth mode is inhibited with a high assisted Ar ion energy. - Abstract: This paper has investigated the impact of the substrate temperature and Ar ion assisted deposition on the surface structure formation mechanism and the film properties during the amorphous TiO_2 thin film deposition process with the molecular dynamics simulation method. The results show that the reduction of the surface roughness happen when the energy of Ar ions assisted is increased or the substrate temperature rises, and also the film density on surface is changed with the increasing of Ar ions energy and substrate temperature. It is also found that the Volmer-Weber (island) growth mode of films is promoted by the lower Ar ion energy and higher substrate temperature when the substrate has an island structure. The assisted Ar ion has power of making a flat surface and increasing the local temperature. Besides, it will influence the growth mode with the change of surface atom mobility. With a high assisted Ar ion energy the Volmer-Weber (island) growth mode is inhibited, which will be conducive to the formation of more smooth film surface.

Influence of trap-assisted tunneling on trap-assisted tunneling current in double gate tunnel field-effect transistor

Science.gov (United States)

Zhi, Jiang; Yi-Qi, Zhuang; Cong, Li; Ping, Wang; Yu-Qi, Liu

2016-02-01

Trap-assisted tunneling (TAT) has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor (TFET). In this paper, we assess subthreshold performance of double gate TFET (DG-TFET) through a band-to-band tunneling (BTBT) model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile (Dit) and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current. Project supported by the National Natural Science Foundation of China (Grant Nos. 61574109 and 61204092).

Superhydrophobic surfaces

Science.gov (United States)

Wang, Evelyn N; McCarthy, Matthew; Enright, Ryan; Culver, James N; Gerasopoulos, Konstantinos; Ghodssi, Reza

2015-03-24

Surfaces having a hierarchical structure--having features of both microscale and nanoscale dimensions--can exhibit superhydrophobic properties and advantageous condensation and heat transfer properties. The hierarchical surfaces can be fabricated using biological nanostructures, such as viruses as a self-assembled nanoscale template.

The importance of internal facial features in learning new faces.

Science.gov (United States)

Longmore, Christopher A; Liu, Chang Hong; Young, Andrew W

2015-01-01

For familiar faces, the internal features (eyes, nose, and mouth) are known to be differentially salient for recognition compared to external features such as hairstyle. Two experiments are reported that investigate how this internal feature advantage accrues as a face becomes familiar. In Experiment 1, we tested the contribution of internal and external features to the ability to generalize from a single studied photograph to different views of the same face. A recognition advantage for the internal features over the external features was found after a change of viewpoint, whereas there was no internal feature advantage when the same image was used at study and test. In Experiment 2, we removed the most salient external feature (hairstyle) from studied photographs and looked at how this affected generalization to a novel viewpoint. Removing the hair from images of the face assisted generalization to novel viewpoints, and this was especially the case when photographs showing more than one viewpoint were studied. The results suggest that the internal features play an important role in the generalization between different images of an individual's face by enabling the viewer to detect the common identity-diagnostic elements across non-identical instances of the face.

Density Functional Theory Study on Defect Feature of AsGaGaAs in Gallium Arsenide

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Deming Ma

2015-01-01

Full Text Available We investigate the defect feature of AsGaGaAs defect in gallium arsenide clusters in detail by using first-principles calculations based on the density functional theory (DFT. Our calculations reveal that the lowest donor level of AsGaGaAs defect on the gallium arsenide crystal surface is 0.85 eV below the conduction band minimum, while the lowest donor level of the AsGaGaAs defect inside the gallium arsenide bulk is 0.83 eV below the bottom of the conduction band, consistent with gallium arsenide EL2 defect level of experimental value (Ec-0.82 eV. This suggests that AsGaGaAs defect is one of the possible gallium arsenide EL2 deep-level defects. Moreover, our results also indicate that the formation energies of internal AsGaGaAs and surface AsGaGaAs defects are predicted to be around 2.36 eV and 5.54 eV, respectively. This implies that formation of AsGaGaAs defect within the crystal is easier than that of surface. Our results offer assistance in discussing the structure of gallium arsenide deep-level defect and its effect on the material.

Detection of norovirus virus-like particles using a surface plasmon resonance-assisted fluoroimmunosensor optimized for quantum dot fluorescent labels.

Science.gov (United States)

Ashiba, Hiroki; Sugiyama, Yuki; Wang, Xiaomin; Shirato, Haruko; Higo-Moriguchi, Kyoko; Taniguchi, Koki; Ohki, Yoshimichi; Fujimaki, Makoto

2017-07-15

A highly sensitive biosensor to detect norovirus in environment is desired to prevent the spread of infection. In this study, we investigated a design of surface plasmon resonance (SPR)-assisted fluoroimmunosensor to increase its sensitivity and performed detection of norovirus virus-like particles (VLPs). A quantum dot fluorescent dye was employed because of its large Stokes shift. The sensor design was optimized for the CdSe-ZnS-based quantum dots. The optimal design was applied to a simple SPR-assisted fluoroimmunosensor that uses a sensor chip equipped with a V-shaped trench. Excitation efficiency of the quantum dots, degree of electric field enhancement by SPR, and intensity of autofluorescence of a substrate of the sensor chip were theoretically and experimentally evaluated to maximize the signal-to-noise ratio. As the result, an excitation wavelength of 390nm was selected to excite SPR on an Al film of the sensor chip. The sandwich assay of norovirus VLPs was performed using the designed sensor. Minimum detectable concentration of 0.01ng/mL, which corresponds to 100 virus-like particles included in the detection region of the V-trench, was demonstrated. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Optimization of microwave-assisted extraction for anthocyanins, polyphenols, and antioxidants from raspberry (Rubus Coreanus Miq.) using response surface methodology.

Science.gov (United States)

Teng, Hui; Lee, Won Young; Choi, Yong Hee

2013-09-01

Anthocyanins (Acys), polyphenols, and antioxidants were extracted from raspberry (Rubus Coreanus Miq.) using a highly efficient microwave-assisted extraction technique. Different solvents, including methanol, ethanol, and acetone, were tested. The colors of the extracts varied from light yellow to purple red or dark red. SEM and other nutrient analyses verified that ethanol was the most favorable medium for the microwave-assisted extraction of raspberry due to its high output and low toxicity. Effects of process parameters, including microwave power, irradiation time, and solvent concentration, were investigated through response surface methodology. Canonical analysis estimated that the highest total Acys content, total polyphenols content, and antioxidant activity of raspberry were 17.93 mg cyanidin-3-O-glucoside equivalents per gram dry weight, 38.57 mg gallic acid equivalents per gram dry weight, and 81.24%, respectively. The polyphenol compositions of raspberry extract were identified by HPLC with diode array detection, and nine kinds of polyphenols were identified and quantified, revealing that chlorogenic acid, syringic acid, and rutin are the major polyphenols contained in raspberry fruits. Compared with other fruits and vegetables, raspberry contains higher Acy and polyphenol contents with stronger antioxidant activity, suggesting that raspberry fruits are a good source of natural food colorants and antioxidants. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Technical assistance contractor management plan: Surface and ground water

International Nuclear Information System (INIS)

1994-09-01

This report presents the general management structure of the Technical Assistance Contractor (TAC) for the Uranium Mill Tailings Remedial Action (UMTRA) Project. This team is a partnership of four major private subcontractors, which teamed together, are striving to be the leader in environmental restoration of uranium mining and milling operations. It will provide a pool of experts in various aspects of the technologies necessary to accomplish this goal, available to DOE to deal with mission concerns. The report expands on goals from TAC's mission statement, which include management concerns, environment, safety, and health, quality, technical support, communications, and personnel

Technical assistance contractor management plan: Surface and ground water

Energy Technology Data Exchange (ETDEWEB)

1994-09-01

This report presents the general management structure of the Technical Assistance Contractor (TAC) for the Uranium Mill Tailings Remedial Action (UMTRA) Project. This team is a partnership of four major private subcontractors, which teamed together, are striving to be the leader in environmental restoration of uranium mining and milling operations. It will provide a pool of experts in various aspects of the technologies necessary to accomplish this goal, available to DOE to deal with mission concerns. The report expands on goals from TAC`s mission statement, which include management concerns, environment, safety, and health, quality, technical support, communications, and personnel.

Minimally invasive registration for computer-assisted orthopedic surgery: combining tracked ultrasound and bone surface points via the P-IMLOP algorithm.

Science.gov (United States)

Billings, Seth; Kang, Hyun Jae; Cheng, Alexis; Boctor, Emad; Kazanzides, Peter; Taylor, Russell

2015-06-01

We present a registration method for computer-assisted total hip replacement (THR) surgery, which we demonstrate to improve the state of the art by both reducing the invasiveness of current methods and increasing registration accuracy. A critical element of computer-guided procedures is the determination of the spatial correspondence between the patient and a computational model of patient anatomy. The current method for establishing this correspondence in robot-assisted THR is to register points intraoperatively sampled by a tracked pointer from the exposed proximal femur and, via auxiliary incisions, from the distal femur. In this paper, we demonstrate a noninvasive technique for sampling points on the distal femur using tracked B-mode ultrasound imaging and present a new algorithm for registering these data called Projected Iterative Most-Likely Oriented Point (P-IMLOP). Points and normal orientations of the distal bone surface are segmented from ultrasound images and registered to the patient model along with points sampled from the exposed proximal femur via a tracked pointer. The proposed approach is evaluated using a bone- and tissue-mimicking leg phantom constructed to enable accurate assessment of experimental registration accuracy with respect to a CT-image-based model of the phantom. These experiments demonstrate that localization of the femur shaft is greatly improved by tracked ultrasound. The experiments further demonstrate that, for ultrasound-based data, the P-IMLOP algorithm significantly improves registration accuracy compared to the standard ICP algorithm. Registration via tracked ultrasound and the P-IMLOP algorithm has high potential to reduce the invasiveness and improve the registration accuracy of computer-assisted orthopedic procedures.

Which Robot Features Can Stimulate Better Responses from Children with Autism in Robot-Assisted Therapy?

Directory of Open Access Journals (Sweden)

Jaeryoung Lee

2012-09-01

Full Text Available This study explores the response of autistic children to a few design features of the robots for autism therapy and provides suggestions on the robot features that have a stronger influence on the therapeutic process. First, we investigate the effect of selected robot features on the development of social communication skills in autistic children. The results indicate that the toy's “face” and “moving limb” usually draw the children's attention and improve children's facial expression skills, but do not contribute to the development of other social communication skills. Secondly, we study the response of children with low-functioning autism to robots with verbal communication functionalities. Test results show that children interacted with the verbal-featured robot more intensively than with the experimenter. We conclude that robots with faces and moving limbs can engage autistic children in a better way. Facial expression of the robots can elicit a greater response than prompting by humans.

Driving with a congestion assistant : mental workload and acceptance

NARCIS (Netherlands)

Brookhuis, K.A.; Driel, C. J.G. van; Hof, T.; Arem, B. van; Hoedemaeker, M.

2009-01-01

New driver support systems are developed and introduced to the market at increasing speed. In conditions of traffic congestion drivers may be supported by a" Congestion Assistant", a system that combines the features of a Congestion Warning System (acoustic warning and gas pedal counterforce) and a

[Assisted suicide in the movies - what is (not) shown?

Science.gov (United States)

Schmidt, Kurt W

2017-01-01

Whereas changes to the existing legal situation regarding assisted suicide have been a topic of controversial debate in Germany for the last few years, this issue has long been of interest for international film-makers. Since the mid-1980s, the theme of assisted suicide has repeatedly been taken up by cinema, predominantly as central to a relationship drama. A sick person asks somebody close to them for help. Often this somebody is a physician or a nurse, ultimately an obvious way of solving the practical problem of how the assistant is to gain access to a lethal substance. At the same time, this constellation enables a physician or nurse to be forced into a dramatic conflict between professional ethics and a personal obligation towards a loved one.Alongside more classic clinical pictures such as terminal cancer, recent films about assisted suicide have featured neurodegenerative diseases and physical disabilities. Another new development is that elderly patients are no longer alone in requesting assistance; films also and increasingly portray young adults. Besides a fear of unbearable pain, more recent films have also increasingly addressed the worry that permanent nursing might be required, as well as the subjectively experienced loss of dignity. The possibilities offered by palliative care hardly play a role in feature films. However, we should not forget, that movies are fictional and orchestrated, or, in other words, they are neither educational nor documental. They neither need nor want to portray reality, although they do wish to draw upon real experiences. They exploit highly emotional and ethically controversial themes to create tensions and stir up emotions in the audience, but ultimately they seek to entertain. Movies about death and dying are always "die-tainment".

Optimization of ultrasonic-assisted extraction of antioxidant compounds from Guava (Psidium guajava L.) leaves using response surface methodology.

Science.gov (United States)

Kong, Fansheng; Yu, Shujuan; Feng, Zeng; Wu, Xinlan

2015-01-01

To optimization of extraction of antioxidant compounds from guava (Psidium guajava L.) leaves and showed that the guava leaves are the potential source of antioxidant compounds. The bioactive polysaccharide compounds of guava leaves (P. guajava L.) were obtained using ultrasonic-assisted extraction. Extraction was carried out according to Box-Behnken central composite design, and independent variables were temperature (20-60°C), time (20-40 min) and power (200-350 W). The extraction process was optimized by using response surface methodology for the highest crude extraction yield of bioactive polysaccharide compounds. The optimal conditions were identified as 55°C, 30 min, and 240 W. 1,1-diphenyl-2-picryl-hydrazyl and hydroxyl free radical scavenging were conducted. The results of quantification showed that the guava leaves are the potential source of antioxidant compounds.

The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source.

Science.gov (United States)

Venkatesan, K

2017-07-01

Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60-150 m/min, feed rates of 0.05-0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

Influence of Structural Features and Fracture Processes on Surface Roughness: A Case Study from the Krosno Sandstones of the Górka–Mucharz Quarry (Little Beskids, Southern Poland

Directory of Open Access Journals (Sweden)

Pieczara Łukasz

2015-09-01

Full Text Available The paper presents the results of analysis of surface roughness parameters in the Krosno Sandstones of Mucharz, southern Poland. It was aimed at determining whether these parameters are influenced by structural features (mainly the laminar distribution of mineral components and directional distribution of non-isometric grains and fracture processes. The tests applied in the analysis enabled us to determine and describe the primary statistical parameters used in the quantitative description of surface roughness, as well as specify the usefulness of contact profilometry as a method of visualizing spatial differentiation of fracture processes in rocks. These aims were achieved by selecting a model material (Krosno Sandstones from the Górka-Mucharz Quarry and an appropriate research methodology. The schedule of laboratory analyses included: identification analyses connected with non-destructive ultrasonic tests, aimed at the preliminary determination of rock anisotropy, strength point load tests (cleaved surfaces were obtained due to destruction of rock samples, microscopic analysis (observation of thin sections in order to determine the mechanism of inducing fracture processes and a test method of measuring surface roughness (two- and three-dimensional diagrams, topographic and contour maps, and statistical parameters of surface roughness. The highest values of roughness indicators were achieved for surfaces formed under the influence of intragranular fracture processes (cracks propagating directly through grains. This is related to the structural features of the Krosno Sandstones (distribution of lamination and bedding.

Study on the construction of multi-dimensional Remote Sensing feature space for hydrological drought

International Nuclear Information System (INIS)

Xiang, Daxiang; Tan, Debao; Wen, Xiongfei; Shen, Shaohong; Li, Zhe; Cui, Yuanlai

2014-01-01

Hydrological drought refers to an abnormal water shortage caused by precipitation and surface water shortages or a groundwater imbalance. Hydrological drought is reflected in a drop of surface water, decrease of vegetation productivity, increase of temperature difference between day and night and so on. Remote sensing permits the observation of surface water, vegetation, temperature and other information from a macro perspective. This paper analyzes the correlation relationship and differentiation of both remote sensing and surface measured indicators, after the selection and extraction a series of representative remote sensing characteristic parameters according to the spectral characterization of surface features in remote sensing imagery, such as vegetation index, surface temperature and surface water from HJ-1A/B CCD/IRS data. Finally, multi-dimensional remote sensing features such as hydrological drought are built on a intelligent collaborative model. Further, for the Dong-ting lake area, two drought events are analyzed for verification of multi-dimensional features using remote sensing data with different phases and field observation data. The experiments results proved that multi-dimensional features are a good method for hydrological drought

Challenges related to flotation cleaning of oil shales. Issues due to compositional and surface features and post-grinding surface behavior

Directory of Open Access Journals (Sweden)

Altun N. Emre

2016-01-01

Full Text Available Oil shale is an important energy resource alternative. Despite its recognition as an unconventional oil source, oil shale is also considered as an important solid fossil fuel alternative to coal and lignites due to the solid form and remarkable extent of organic content. Utilization possibilites, similar to coal and lignites, have been considered in the past decades and direct use of oil shales in thermal power production has been possible in countries like Estonia and China. In the perspective of utilization of oil shales in a similar manner to coal and lignites, problems and restrictions related to the inorganic ash-making and potentially pollutant constituents are applied. In this respect, cleaning of this important energy source through mineral processing methods, particularly by flotation, is an outstanding option. However, on the basis of unique features and distinctive characteristics, treatment of oil shales like a type of coal is a big perception and may be highly misleading. This paper discusses specific challenges regarding flotation behavior of oil shales with reference to the surface characteristics and behavior of oil shale entities – probably the most important aspect that determines the efficiency and success of the flotation based cleaning process.

A new karren feature: hummocky karren

Directory of Open Access Journals (Sweden)

Plan Lukas

2012-01-01

Full Text Available Karren are small-scale landforms on karst surfaces and many types have been described so far. Here we present an apparently new feature which was found on the Hochschwab karst massive in the Northern Calcareous Alps of Austria. So far only few outcrops each having less than 1 m² within a very restricted area have been found. Morphometric analysis reveals that the karren consist of a randomly distributed, dispersed assemblage of small hummocks and depressions in between. The mean distance between neighbouring hummocks is 4 to 5 cm and the mean height is 0.85 cm. Longitudinal sections are gently sinuous. The occurrences are delimited by thin soil cover with grassy vegetation and the karren continue below that vegetation cover. Therefore, it is clear that the features have formed subcutaneously. Corroded fissures where water could infiltrate into the epikarst are absent. The bedrock lithology is Middle Triassic limestone of the Wetterstein Formation in lagoonal facies. Geological structures do not govern the feature. The surface is not a bedding plane and small joints and fractures do not govern the arrangement of the hummocks. Thin section analysis regarding rock texture and dolomite components show that there is no compositional difference between hummocks and depressions. Geochemical analyses show that the limestone is very pure with a very low content of Magnesia. Slightly higher Magnesia contents at the hummock surfaces are significant. The data obtained so far only indicate that some dissolution mechanism but not any rock property governs the irregular array. As there exist no descriptions of comparable features in literature, the name “hummocky karren” is suggested for that type of karren landform.

Molecular dynamics study of the effect of substrate temperature and Ar ion assisted deposition on the deposition of amorphous TiO{sub 2} films

Energy Technology Data Exchange (ETDEWEB)

Chen, Xian, E-mail: mus_c@qq.com [Science and Technology on Analog Integrated Circuit Laboratory, ChongQing, 401332 (China); Zhang, Jing [Science and Technology on Analog Integrated Circuit Laboratory, ChongQing, 401332 (China); Zhao, Yu-Qing [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’AN, 710049 (China)

2017-05-15

Highlights: • The surface roughness of a-TiO{sub 2} films is decreased with the increment of the Ar ion assisted energy. • The surface roughness of a-TiO{sub 2} films is decreased with higher substrate temperature when the substrate has an island structure. • The assisted Ar ion has power of making a flat surface and increasing the local temperature. • The assisted Ar ion will influence the growth mode with the change of surface atom mobility. • The Volmer-Weber (island) growth mode is inhibited with a high assisted Ar ion energy. - Abstract: This paper has investigated the impact of the substrate temperature and Ar ion assisted deposition on the surface structure formation mechanism and the film properties during the amorphous TiO{sub 2} thin film deposition process with the molecular dynamics simulation method. The results show that the reduction of the surface roughness happen when the energy of Ar ions assisted is increased or the substrate temperature rises, and also the film density on surface is changed with the increasing of Ar ions energy and substrate temperature. It is also found that the Volmer-Weber (island) growth mode of films is promoted by the lower Ar ion energy and higher substrate temperature when the substrate has an island structure. The assisted Ar ion has power of making a flat surface and increasing the local temperature. Besides, it will influence the growth mode with the change of surface atom mobility. With a high assisted Ar ion energy the Volmer-Weber (island) growth mode is inhibited, which will be conducive to the formation of more smooth film surface.

Plasma-assisted cleaning of extreme UV optics

NARCIS (Netherlands)

Dolgov, Alexandr Alexeevich

2018-01-01

Plasma-assisted cleaning of extreme UV optics EUV-induced surface plasma chemistry of photo-active agents The next generation of photolithography, extreme ultraviolet (EUV) lithography, makes use of 13.5 nm radiation. The ionizing photon flux, and vacuum requirements create a challenging operating

Pupil size reflects the focus of feature-based attention.

Science.gov (United States)

Binda, Paola; Pereverzeva, Maria; Murray, Scott O

2014-12-15

We measured pupil size in adult human subjects while they selectively attended to one of two surfaces, bright and dark, defined by coherently moving dots. The two surfaces were presented at the same location; therefore, subjects could select the cued surface only on the basis of its features. With no luminance change in the stimulus, we find that pupil size was smaller when the bright surface was attended and larger when the dark surface was attended: an effect of feature-based (or surface-based) attention. With the same surfaces at nonoverlapping locations, we find a similar effect of spatial attention. The pupil size modulation cannot be accounted for by differences in eye position and by other variables known to affect pupil size such as task difficulty, accommodation, or the mere anticipation (imagery) of bright/dark stimuli. We conclude that pupil size reflects not just luminance or cognitive state, but the interaction between the two: it reflects which luminance level in the visual scene is relevant for the task at hand. Copyright © 2014 the American Physiological Society.

Salient features in 3-D haptic shape perception

NARCIS (Netherlands)

Plaisier, Myrthe A; Bergmann Tiest, Wouter M.; Kappers, Astrid M L

2009-01-01

Shape is an important cue for recognizing an object by touch. Several features, such as edges, curvature, surface area, and aspect ratio, are associated with 3-D shape. To investigate the saliency of 3-D shape features, we developed a haptic search task. The target and distractor items consisted of

Ion-assisted deposition of thin films

International Nuclear Information System (INIS)

Barnett, S.A.; Choi, C.H.; Kaspi, R.; Millunchick, J.M.

1993-01-01

Recent work on low-energy ion-assisted deposition of epitaxial films is reviewed. Much of the recent interest in this area has been centered on the use of very low ion energies (∼ 25 eV) and high fluxes (> 1 ion per deposited atom) obtained using novel ion-assisted deposition techniques. These methods have been applied in ultra-high vacuum, allowing the preparation of high-purity device-quality semiconductor materials. The following ion-surface interaction effects during epitaxy are discussed: improvements in crystalline perfection during low temperature epitaxy, ion damage, improved homogeneity and properties in III-V alloys grown within miscibility gaps, and changes in nucleation mechanism during heteroepitaxial growth

Rapid determination of trace nitrophenolic organics in water by combining solid-phase extraction with surface-assisted laser desorption/ionization time-of-flight mass spectrometry.

Science.gov (United States)

Chen, Y C; Shiea, J; Sunner, J

2000-01-01

A rapid technique for the screening of trace compounds in water by combining solid-phase extraction (SPE) with activated carbon surface-assisted laser desorption/ionization (SALDI) time-of-flight mass spectrometry is demonstrated. Activated carbon is used both as the sorbent in SPE and as the solid in the SALDI matrix system. This eliminates the need for an SPE elution process. After the analytes have been adsorbed on the surfaces of the activated carbon during SPE extraction, the activated carbon is directly mixed with the SALDI liquid and mass spectrometric analysis is performed. Trace phenolic compounds in water were used to demonstrate the effectiveness of the method. The detection limit for these compounds is in the ppb to ppt range. Copyright 2000 John Wiley & Sons, Ltd.

Research status in ultra-precision machining of silicon carbide parts by oxidation-assisted polishing

Directory of Open Access Journals (Sweden)

Xinmin SHEN

2016-10-01

Full Text Available Oxidation-assisted polishing is an important machining method for obtaining SiC parts with high precision. Through plasma oxidation, thermal oxidation, and anodic oxidation, soft oxide can be obtained on the RS-SiC substrate. With the assistance of abrasive polishing to remove the oxide rapidly, the material removal rate can be increased and the surface quality can be improved. The research results indicate that the surface roughness root-mean-square (RMS and roughness-average (Ra can reach 0.626 nm and 0.480 nm by plasma oxidation-assisted polishing; in thermal oxidation-assisted polishing, the RMS and Ra can be 0.920 nm and 0.726 nm; in anodic oxidation, the calculated oxidation rate is 5.3 nm/s based on Deal-Grove model, and the RMS and Ra are 4.428 nm and 3.453 nm respectively in anodic oxidation-assisted polishing. The oxidation-assisted polishing can be propitious to improve the process level in machining RS-SiC, which would promote the application of SiC parts in optics and ceramics fields.

Controllable edge feature sharpening for dental applications.

Science.gov (United States)

Fan, Ran; Jin, Xiaogang

2014-01-01

This paper presents a new approach to sharpen blurred edge features in scanned tooth preparation surfaces generated by structured-light scanners. It aims to efficiently enhance the edge features so that the embedded feature lines can be easily identified in dental CAD systems, and to avoid unnatural oversharpening geometry. We first separate the feature regions using graph-cut segmentation, which does not require a user-defined threshold. Then, we filter the face normal vectors to propagate the geometry from the smooth region to the feature region. In order to control the degree of the sharpness, we propose a feature distance measure which is based on normal tensor voting. Finally, the vertex positions are updated according to the modified face normal vectors. We have applied the approach to scanned tooth preparation models. The results show that the blurred edge features are enhanced without unnatural oversharpening geometry.

Controllable Edge Feature Sharpening for Dental Applications

Directory of Open Access Journals (Sweden)

Ran Fan

2014-01-01

Full Text Available This paper presents a new approach to sharpen blurred edge features in scanned tooth preparation surfaces generated by structured-light scanners. It aims to efficiently enhance the edge features so that the embedded feature lines can be easily identified in dental CAD systems, and to avoid unnatural oversharpening geometry. We first separate the feature regions using graph-cut segmentation, which does not require a user-defined threshold. Then, we filter the face normal vectors to propagate the geometry from the smooth region to the feature region. In order to control the degree of the sharpness, we propose a feature distance measure which is based on normal tensor voting. Finally, the vertex positions are updated according to the modified face normal vectors. We have applied the approach to scanned tooth preparation models. The results show that the blurred edge features are enhanced without unnatural oversharpening geometry.

Human Gait Feature Extraction Including a Kinematic Analysis toward Robotic Power Assistance

Directory of Open Access Journals (Sweden)

Mario I. Chacon-Murguia

2012-09-01

Full Text Available The present work proposes a method for human gait and kinematic analysis. Gait analysis consists of the determination of hip, knee and ankle positions through video analysis. Gait kinematic for the thigh and knee is then generated from this data. Evaluations of the gait analysis method indicate an acceptable performance of 86.66% for hip and knee position estimation, and comparable findings with other reported works for gait kinematic. A coordinate systems assignment is performed according to the DH algorithm and a direct kinematic model of the legs is obtained. The legs' angles obtained from the video analysis are applied to the kinematic model in order to revise the application of this model to robotic legs in a power assisted system.

Characterization of ethylcellulose and hydroxypropyl methylcellulose thin films deposited by matrix-assisted pulsed laser evaporation

Energy Technology Data Exchange (ETDEWEB)

Palla-Papavlu, A., E-mail: apalla@nipne.ro [National Institute for Lasers, Plasma and Radiation Physics, PO Box MG-36, Magurele, RO-077125 Bucharest (Romania); Rusen, L.; Dinca, V.; Filipescu, M. [National Institute for Lasers, Plasma and Radiation Physics, PO Box MG-36, Magurele, RO-077125 Bucharest (Romania); Lippert, T. [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen PSI (Switzerland); Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, PO Box MG-36, Magurele, RO-077125 Bucharest (Romania)

2014-05-01

In this study is reported the deposition of hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC) by matrix-assisted pulsed laser evaporation (MAPLE). Both HPMC and EC were deposited on silicon substrates using a Nd:YAG laser (266 nm, 5 ns laser pulse and 10 Hz repetition rate) and then characterized by atomic force microscopy and Fourier transform infrared spectroscopy. It was found that for laser fluences up to 450 mJ/cm{sup 2} the structure of the deposited HPMC and EC polymer in the thin film resembles to the bulk. Morphological investigations reveal island features on the surface of the EC thin films, and pores onto the HPMC polymer films. The obtained results indicate that MAPLE may be an alternative technique for the fabrication of new systems with desired drug release profile.

Characterization of ethylcellulose and hydroxypropyl methylcellulose thin films deposited by matrix-assisted pulsed laser evaporation

Science.gov (United States)

Palla-Papavlu, A.; Rusen, L.; Dinca, V.; Filipescu, M.; Lippert, T.; Dinescu, M.

2014-05-01

In this study is reported the deposition of hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC) by matrix-assisted pulsed laser evaporation (MAPLE). Both HPMC and EC were deposited on silicon substrates using a Nd:YAG laser (266 nm, 5 ns laser pulse and 10 Hz repetition rate) and then characterized by atomic force microscopy and Fourier transform infrared spectroscopy. It was found that for laser fluences up to 450 mJ/cm2 the structure of the deposited HPMC and EC polymer in the thin film resembles to the bulk. Morphological investigations reveal island features on the surface of the EC thin films, and pores onto the HPMC polymer films. The obtained results indicate that MAPLE may be an alternative technique for the fabrication of new systems with desired drug release profile.

Volume Decomposition and Feature Recognition for Hexahedral Mesh Generation

Energy Technology Data Exchange (ETDEWEB)

GADH,RAJIT; LU,YONG; TAUTGES,TIMOTHY J.

1999-09-27

Considerable progress has been made on automatic hexahedral mesh generation in recent years. Several automatic meshing algorithms have proven to be very reliable on certain classes of geometry. While it is always worth pursuing general algorithms viable on more general geometry, a combination of the well-established algorithms is ready to take on classes of complicated geometry. By partitioning the entire geometry into meshable pieces matched with appropriate meshing algorithm the original geometry becomes meshable and may achieve better mesh quality. Each meshable portion is recognized as a meshing feature. This paper, which is a part of the feature based meshing methodology, presents the work on shape recognition and volume decomposition to automatically decompose a CAD model into meshable volumes. There are four phases in this approach: (1) Feature Determination to extinct decomposition features, (2) Cutting Surfaces Generation to form the ''tailored'' cutting surfaces, (3) Body Decomposition to get the imprinted volumes; and (4) Meshing Algorithm Assignment to match volumes decomposed with appropriate meshing algorithms. The feature determination procedure is based on the CLoop feature recognition algorithm that is extended to be more general. Results are demonstrated over several parts with complicated topology and geometry.

Improved pulmonary nodule classification utilizing quantitative lung parenchyma features.

Science.gov (United States)

Dilger, Samantha K N; Uthoff, Johanna; Judisch, Alexandra; Hammond, Emily; Mott, Sarah L; Smith, Brian J; Newell, John D; Hoffman, Eric A; Sieren, Jessica C

2015-10-01

Current computer-aided diagnosis (CAD) models for determining pulmonary nodule malignancy characterize nodule shape, density, and border in computed tomography (CT) data. Analyzing the lung parenchyma surrounding the nodule has been minimally explored. We hypothesize that improved nodule classification is achievable by including features quantified from the surrounding lung tissue. To explore this hypothesis, we have developed expanded quantitative CT feature extraction techniques, including volumetric Laws texture energy measures for the parenchyma and nodule, border descriptors using ray-casting and rubber-band straightening, histogram features characterizing densities, and global lung measurements. Using stepwise forward selection and leave-one-case-out cross-validation, a neural network was used for classification. When applied to 50 nodules (22 malignant and 28 benign) from high-resolution CT scans, 52 features (8 nodule, 39 parenchymal, and 5 global) were statistically significant. Nodule-only features yielded an area under the ROC curve of 0.918 (including nodule size) and 0.872 (excluding nodule size). Performance was improved through inclusion of parenchymal (0.938) and global features (0.932). These results show a trend toward increased performance when the parenchyma is included, coupled with the large number of significant parenchymal features that support our hypothesis: the pulmonary parenchyma is influenced differentially by malignant versus benign nodules, assisting CAD-based nodule characterizations.

Preparation of silica nanoparticles through microwave-assisted acid-catalysis.

Science.gov (United States)

Lovingood, Derek D; Owens, Jeffrey R; Seeber, Michael; Kornev, Konstantin G; Luzinov, Igor

2013-12-16

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan δ solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials' morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by Stöber's methods, which have smooth surfaces.

Photon management assisted by surface waves on photonic crystals

CERN Document Server

Angelini, Angelo

2017-01-01

This book illustrates original pathways to manipulate light at the nanoscale by means of surface electromagnetic waves (here, Bloch surface waves, BSWs) on planar dielectric multilayers, also known as one-dimensional photonic crystals. This approach is particularly valuable as it represents an effective alternative to the widely exploited surface plasmon paradigm. After a brief overview on the fundamentals of BSWs, several significant applications of BSW-sustaining structures are described. Particular consideration is given to the propagation, guiding, and diffraction of BSW-coupled radiation. Further, the interaction of organic emitters with BSWs on planar and corrugated multilayers is investigated, including fluorescence beaming in free space. To provide greater insight into sensing applications, an illustrative example of fluorescent microarray-based detection is presented. The book is intended for scientists and researchers working on photon management opportunities in fields such as biosensing, optical c...

Image simulation and surface reconstruction of undercut features in atomic force microscopy

Science.gov (United States)

Qian, Xiaoping; Villarrubia, John; Tian, Fenglei; Dixson, Ronald

2007-03-01

CD-AFMs (critical dimension atomic force microscopes) are instruments with servo-control of the tip in more than one direction. With appropriately "boot-shaped" or flared tips, such instruments can image vertical or even undercut features. As with any AFM, the image is a dilation of the sample shape with the tip shape. Accurate extraction of the CD requires a correction for the tip effect. Analytical methods to correct images for the tip shape have been available for some time for the traditional (vertical feedback only) AFMs, but were until recently unavailable for instruments with multi-dimensional feedback. Dahlen et al. [J. Vac. Sci. Technol. B23, pp. 2297-2303, (2005)] recently introduced a swept-volume approach, implemented for 2-dimensional (2D) feedback. It permits image simulation and sample reconstruction, techniques previously developed for the traditional instruments, to be extended for the newer tools. We have introduced [X. Qian and J. S. Villarrubia, Ultramicroscopy, in press] an alternative dexel-based method, that does the same in either 2D or 3D. This paper describes the application of this method to sample shapes of interest in semiconductor manufacturing. When the tip shape is known (e.g., by prior measurement using a tip characterizer) a 3D sample surface may be reconstructed from its 3D image. Basing the CD measurement upon such a reconstruction is shown here to remove some measurement artifacts that are not removed (or are incompletely removed) by the existing measurement procedures.

Study on the effect of thermal property of metals in ultrasonic-assisted laser machining

International Nuclear Information System (INIS)

Lee, Hu Seung; Kim, Gun Woo; Park, Jong Eun; Cho, Sung Hak; Yang, Min Yang; Park, Jong Kweon

2015-01-01

The laser machining process has been proposed as an advanced process for the selective fabrication of electrodes without a mask. In this study, we adapt laser machining to metals that have different thermal properties. Based on the results, the metals exhibit a different surface morphology, heat-affected zone (HAZ), and a recast layer around the machined surface according to their thermal conductivity, boiling point, and thermal diffusivity. Then, we apply ultrasonic-assisted laser machining to remove the recast layer. The ultrasonic-assisted laser machining exhibits a better surface quality in metals with higher diffusivity than those having lower diffusivity

Development on smart suit for dairy work assistance.

Science.gov (United States)

Nara, Hiroyuki; Kusaka, Takashi; Tanaka, Takayuki; Yamagishi, Takayuki; Ogura, Shotaroh

2013-01-01

Our purpose in this study is to achieve an independent life and a social involvement for the elderly using KEIROKA Technology(fatigue-reduction) which makes it possible to improve the quality of chores and occupations by removing excessive strain and tiredness. The authors have developed power assist suits named "smart suit". The authors have evaluated the effect that the purpose of dairy work assistance, to measure EMG of the worker, compared to the potential of the surface of the non-wearing and wearing "smart suit".

Refining femtosecond laser induced periodical surface structures with liquid assist

International Nuclear Information System (INIS)

Jiao, L.S.; Ng, E.Y.K.; Zheng, H.Y.

2013-01-01

Highlights: ► LIPSS on silicon wafer was made in air and in ethanol environment. ► Ethanol environment produce cleaner surface ripples. ► Ethanol environment decrease spatial wavelength of the LIPSS by 30%. ► More number of pulses produce smaller spatial wavelength in air. ► Number of pulses do not influence spatial wavelength in ethanol environment. - Abstract: Laser induced periodic surface structures were generated on silicon wafer using femtosecond laser. The medium used in this study is both air and ethanol. The laser process parameters such as wavelength, number of pulse, laser fluence were kept constant for both the mediums. The focus of the study is to analyze spatial wavelength. When generating surface structures with air as a medium and same process parameter of the laser, spatial wavelength results showed a 30% increase compared to ethanol. The cleanliness of the surface generated using ethanol showed considerably less debris than in air. The results observed from the above investigation showed that the medium plays a predominant role in the generation of surface structures.

Assisting Gas Optimization in CO2 Laser Welding

DEFF Research Database (Denmark)

Gong, Hui; Olsen, Flemming Ove

1996-01-01

High quality laser welding is achieved under the condition of optimizing all process parameters. Assisting gas plays an important role for sound welds. In the conventional welding process assisting gas is used as a shielding gas to prevent that the weld seam oxidates. In the laser welding process...... assisting gas is also needed to control the laser induced plasma.Assisting gas is one of the most important parameters in the laser welding process. It is responsible for obtaining a quality weld which is characterized by deep penetration, no interior imperfections, i.e. porosity, no crack, homogeneous seam...... surface, etc. In this work a specially designed flexible off-axis nozzle capable of adjusting the angle of the nozzle, the diameter of the nozzle, and the distance between the nozzle end and the welding zone is tested. In addition to the nozzle parameters three gases, Nitrogen, Argon, and Helium...

Human-robot interaction tests on a novel robot for gait assistance.

Science.gov (United States)

Tagliamonte, Nevio Luigi; Sergi, Fabrizio; Carpino, Giorgio; Accoto, Dino; Guglielmelli, Eugenio

2013-06-01

This paper presents tests on a treadmill-based non-anthropomorphic wearable robot assisting hip and knee flexion/extension movements using compliant actuation. Validation experiments were performed on the actuators and on the robot, with specific focus on the evaluation of intrinsic backdrivability and of assistance capability. Tests on a young healthy subject were conducted. In the case of robot completely unpowered, maximum backdriving torques were found to be in the order of 10 Nm due to the robot design features (reduced swinging masses; low intrinsic mechanical impedance and high-efficiency reduction gears for the actuators). Assistance tests demonstrated that the robot can deliver torques attracting the subject towards a predicted kinematic status.

The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source

Directory of Open Access Journals (Sweden)

K. Venkatesan

2017-07-01

Full Text Available Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60–150 m/min, feed rates of 0.05–0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

Optimization of ultrasound-assisted extraction of charantin from Momordica charantia fruits using response surface methodology.

Science.gov (United States)

Ahamad, Javed; Amin, Saima; Mir, Showkat R

2015-01-01

Momordica charantia Linn. (Cucurbitaceae) fruits are well known for their beneficial effects in diabetes that are often attributed to its bioactive component charantin. The aim of the present study is to develop and optimize an efficient protocol for the extraction of charantin from M. charantia fruits. Response surface methodology (RSM) was used for the optimization of ultrasound-assisted extraction (UAE) conditions. RSM was based on a three-level, three-variable Box-Behnken design (BBD), and the studied variables included solid to solvent ratio, extraction temperature, and extraction time. The optimal conditions predicted by the BBD were: UAE with methanol: Water (80:20, v/v) at 46°C for 120 min with solid to solvent ratio of 1:26 w/v, under which the yield of charantin was 3.18 mg/g. Confirmation trials under slightly adjusted conditions yielded 3.12 ± 0.14 mg/g of charantin on dry weight basis of fruits. The result of UAE was also compared with Soxhlet extraction method and UAE was found 2.74-fold more efficient than the Soxhlet extraction for extracting charantin. A facile UAE protocol for a high extraction yield of charantin was developed and validated.

Optimization of ultrasonic-assisted extraction of natural antioxidants from rice bran using response surface methodology.

Science.gov (United States)

Tabaraki, Reza; Nateghi, Ashraf

2011-11-01

Ultrasonic technology was applied for extraction of polyphenols and antioxidants from the rice bran using ethanol as a food grade solvent. Response surface methodology (RSM) was used to optimize experimental conditions for extraction of polyphenols and antioxidants. Three independent variables such as solvent percentage (%), temperature (°C) and time (min) were studied. Effect of ethanol concentration was found to be significant on all responses. Total phenolic content (TPC) varied from 2.37 to 6.35mg gallic acid equivalent/g of dry sample. Antioxidant activity of the extracts was determined by the ferric reducing antioxidant power (FRAP) assay and scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. FRAP and DPPH values varied from 31.74 to 57.23μmol Fe(2+)/g of dry sample and 16.88% to 55.61% inhibition, respectively. Extraction yields ranged from 11 to 20.2%. Optimal ultrasonic-assisted extraction (UAE) conditions were identified as 65-67% ethanol, 51-54°C, 40-45min. The experimental values agreed with those predicted by SRM models, thus indicating suitability of the model employed and the success of RSM in optimizing the extraction conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

Part-based Pedestrian Detection and Feature-based Tracking for Driver Assistance

DEFF Research Database (Denmark)

Prioletti, Antonio; Møgelmose, Andreas; Grislieri, Paolo

2013-01-01

Detecting pedestrians is still a challenging task for automotive vision systems due to the extreme variability of targets, lighting conditions, occlusion, and high-speed vehicle motion. Much research has been focused on this problem in the last ten years and detectors based on classifiers have...... on a prototype vehicle and offers high performance in terms of several metrics, such as detection rate, false positives per hour, and frame rate. The novelty of this system relies on the combination of a HOG part-based approach, tracking based on a specific optimized feature, and porting on a real prototype....

The Langmuir isotherm and the standard model of ion-assisted etching

International Nuclear Information System (INIS)

Lieberman, M A

2009-01-01

Langmuir is lured to the General Electric Research Laboratory, where he creates a new science-surface chemistry-and christens another-plasma. His atomistic views of gas-surface interactions are extended 65 years later to describe ion-assisted plasma etching, an indispensable process in modern semiconductor device manufacturing.

Plastic deformation to enhance plasma-assisted nitriding: On surface contamination induced by Surface Mechanical Attrition Treatment

International Nuclear Information System (INIS)

Samih, Youssef; Novelli, Marc; Bolle, Bernard; Allain, Nathalie; Fundenberger, Jean-Jacques; Marcos, Grégory; Czerwiec, Thierry; Grosdidier, Thierry; Thiriet, Tony

2014-01-01

The Surface Mechanical Attrition Treatment is a recent technique leading to the formation of nanostructured layers by the repeated action of impacting balls. While several communications have revealed possible contamination of the SMATed surfaces, the nature of this surface contamination was analyzed in the present contribution for the treatment of an AISI 316L stainless steel. It is shown, by a combination of Transmission Electron Microscopy and Glow Discharge – Optical Emission Spectrometry, that the surface was alloyed with Ti, Al and V coming from the sonotrode that is used to move the balls as well as Zr coming from the zirshot® balls themselves

Plastic deformation to enhance plasma-assisted nitriding: On surface contamination induced by Surface Mechanical Attrition Treatment

Science.gov (United States)

Samih, Youssef; Novelli, Marc; Thiriet, Tony; Bolle, Bernard; Allain, Nathalie; Fundenberger, Jean-Jacques; Marcos, Grégory; Czerwiec, Thierry; Grosdidier, Thierry

2014-08-01

The Surface Mechanical Attrition Treatment is a recent technique leading to the formation of nanostructured layers by the repeated action of impacting balls. While several communications have revealed possible contamination of the SMATed surfaces, the nature of this surface contamination was analyzed in the present contribution for the treatment of an AISI 316L stainless steel. It is shown, by a combination of Transmission Electron Microscopy and Glow Discharge - Optical Emission Spectrometry, that the surface was alloyed with Ti, Al and V coming from the sonotrode that is used to move the balls as well as Zr coming from the zirshot® balls themselves.

Optimization of Ultrasound-Assisted Extraction of Antioxidants from Apium graveolens L. Seeds using Response Surface Methodology

Directory of Open Access Journals (Sweden)

Şule Dinç Zor

2017-09-01

Full Text Available In this study, optimum conditions for ultrasound-assisted extraction (UAE of antioxidants from Apium graveolens L. seeds were investigated by Response Surface Methodology (RSM. A Box-Behnken Design (BBD was used to evaluate the effect of sonication time (5, 10, 15 min, ultrasound power (60, 120, 180 W and the ratio of extraction solvent in terms of methanol (0, 50, 100% on antioxidant capacity. The optimal UAE conditions for the parameters investigated were 11 min of sonication time, ultrasound power of 131 W and 100% methanol as an extraction solvent. Under these conditions, UAE of antioxidants from the seeds achieved a maximum of 95.08% in respect to 1,1-diphenyl-2-picryl hydrazyl (DPPH radical scavenging activity. Additionally, the high value of the adjusted coefficient of determination (R2adj = 0.9192 and the non-significant difference between experimental and predicted values confirmed the validity of the quadratic polynomial model. Hence, UAE is a suitable, fast, economical and practical technique for the extraction of antioxidants from Apium graveolens L. seeds.

Optimization of ultrasound-assisted extraction of colchicine compound from Colchicum haussknechtii by using response surface methodology

Directory of Open Access Journals (Sweden)

Saeid Khodadoust

2017-04-01

Full Text Available In this research an ultrasound-assisted extraction (UAE method was used for extraction of colchicine in root of Colchicum haussknechtii prior to high-performance liquid chromatography with UV detection. C. haussknechtii is used widely in traditional medicine for the treatment of various diseases. The root of this plant is full of colchicine that is suitable for the treatment of gout and cirrhosis and applicable in plant breeding studies to produce polyploidy. The influence of variables on the extraction method was investigated by response surface methodology (RSM and composite design (CCD to achieve maximum extraction yield of colchicine from the root of C. haussknechtii. The most suitable condition for the extraction of colchicine was found to at 40 °C temperature, 32 min extraction time, and 70:30 v/v ethanol–water mixtures with 45:1 solvent-solid ratio. Obtained results showed that there is 1.2% colchicine in the root of C. haussknechtii, so this plant could be introduced as a rich source of colchicine.

Nanoparticle assisted laser desorption/ionization mass spectrometry for small molecule analytes.

Science.gov (United States)

Abdelhamid, Hani Nasser

2018-03-01

Nanoparticle assisted laser desorption/ionization mass spectrometry (NPs-ALDI-MS) shows remarkable characteristics and has a promising future in terms of real sample analysis. The incorporation of NPs can advance several methods including surface assisted LDI-MS, and surface enhanced LDI-MS. These methods have advanced the detection of many thermally labile and nonvolatile biomolecules. Nanoparticles circumvent the drawbacks of conventional organic matrices for the analysis of small molecules. In most cases, NPs offer a clear background without interfering peaks, absence of fragmentation of thermally labile molecules, and allow the ionization of species with weak noncovalent interactions. Furthermore, an enhancement in sensitivity and selectivity can be achieved. NPs enable straightforward analysis of target species in a complex sample. This review (with 239 refs.) covers the progress made in laser-based mass spectrometry in combination with the use of metallic NPs (such as AuNPs, AgNPs, PtNPs, and PdNPs), NPs consisting of oxides and chalcogenides, silicon-based NPs, carbon-based nanomaterials, quantum dots, and metal-organic frameworks. Graphical abstract An overview is given on nanomaterials for use in surface-assisted laser desorption/ionization mass spectrometry of small molecules.

Collaborative Tracking of Image Features Based on Projective Invariance

Science.gov (United States)

Jiang, Jinwei

In past manned lunar landing missions, such as Apollo 14, spatial disorientation of astronauts substantially compromised the productivities of astronauts, and caused safety and mission success problems. The non-GPS lunar environment has micro-gravity field, and lacks both spatial recognition cues and reference objects which are familiar to the human biological sensors related to spatial recognition (e.g. eyes). Such an environment causes misperceptions of the locations of astronauts and targets and their spatial relations, as well as misperceptions of the heading direction and travel distances of astronauts. These spatial disorientation effects can reduce productivity and cause life risks in lunar manned missions. A navigation system, which is capable of locating astronauts and tracking the movements of them on the lunar surface, is critical for future lunar manned missions where multiple astronauts will traverse more than 100km from the lander or the base station with the assistance from roving vehicle, and need real-time navigation support for effective collaborations among them. Our earlier research to solve these problems dealt with developing techniques to enable a precise, flexible and reliable Lunar Astronaut Spatial Orientation and Information System (LASOIS) capable of delivering real-time navigation information to astronauts on the lunar surface. The LASOIS hardware was a sensor network composed of orbital, ground and on-suit sensors: the Lunar Reconnaissance Orbiter Camera (LROC), radio beacons, the on-suit cameras, and shoe-mounted Inertial Measurement Unit (IMU). The LASOIS software included efficient and robust algorithms for estimating trajectory from IMU signals, generating heading information from imagery acquired from on-suit cameras, and an Extended Kalman Filter (EKF) based approach for integrating these spatial information components to generate the trajectory of an astronaut with meter-level accuracy. Moreover, LASOIS emphasized multi

HNO₃-assisted polyol synthesis of ultralarge single-crystalline Ag microplates and their far propagation length of surface plasmon polariton.

Science.gov (United States)

Chang, Cheng-Wei; Lin, Fan-Cheng; Chiu, Chun-Ya; Su, Chung-Yi; Huang, Jer-Shing; Perng, Tsong-Pyng; Yen, Ta-Jen

2014-07-23

We developed a HNO3-assisted polyol reduction method to synthesize ultralarge single-crystalline Ag microplates routinely. The edge length of the synthesized Ag microplates reaches 50 μm, and their top facets are (111). The mechanism for dramatically enlarging single-crystalline Ag structure stems from a series of competitive anisotropic growths, primarily governed by carefully tuning the adsorption of Ag(0) by ethylene glycol and the desorption of Ag(0) by a cyanide ion on Ag(100). Finally, we measured the propagation length of surface plasmon polaritons along the air/Ag interface under 534 nm laser excitation. Our single-crystalline Ag microplate exhibited a propagation length (11.22 μm) considerably greater than that of the conventional E-gun deposited Ag thin film (5.27 μm).

Nanorods on surface of GaN-based thin-film LEDs deposited by post-annealing after photo-assisted chemical etching

Science.gov (United States)

Chen, Lung-Chien; Lin, Wun-Wei; Liu, Te-Yu

2017-01-01

This study investigates the optoelectronic characteristics of gallium nitride (GaN)-based thin-film light-emitting diodes (TF-LEDs) that are formed by a two-step transfer process that involves wet etching and post-annealing. In the two-step transfer process, GaN LEDs were stripped from sapphire substrates by the laser lift-off (LLO) method using a KrF laser and then transferred onto ceramic substrates. Ga-K nanorods were formed on the surface of the GaN-based TF-LEDs following photo-assisted chemical etching and photo-enhanced post-annealing at 100 °C for 1 min. As a result, the light output power of GaN-based TF-LEDs with wet etching and post-annealing was over 72% more than that of LEDs that did not undergo these treatments.

A Review of Technology-Assisted Interventions for Diabetes Prevention.

Science.gov (United States)

Grock, Shira; Ku, Jeong-Hee; Kim, Julie; Moin, Tannaz

2017-09-23

The high prevalence of prediabetes and success of the diabetes prevention program (DPP) has led to increasing efforts to provide readily accessible, cost-effective DPP interventions to the general public. Technology-assisted DPP interventions are of particular interest since they may be easier to widely distribute and sustain as compared to traditional in-person DPP. The purpose of this article is to provide an overview of currently available technology-assisted DPP interventions. This review focuses on studies that have examined the use of mobile phone text messaging, smartphone/web-based apps, and telehealth programs to help prevent or delay the onset of incident type 2 diabetes. While there is variability in the results of studies focused on technology-assisted DPP and weight loss interventions, there is evidence to suggest that these programs have been associated with clinically meaningful weight loss and can be cost-effective. Patients who are at risk for diabetes can be offered technology-assisted DPP and weight loss interventions to lower their risk of incident diabetes. Further research should determine what specific combination of intervention features would be most successful.

The Sliced Pineapple Grid Feature for Predicting Grasping Affordances

DEFF Research Database (Denmark)

Thomsen, Mikkel Tang; Kraft, Dirk; Krüger, Norbert

2017-01-01

The problem of grasping unknown objects utilising vision is addressed in this work by introducing a novel feature, the Sliced Pineapple Grid Feature (SPGF). The SPGF encode semi-local surfaces and allows for distinguishing structures such as “walls”,“edges” and “rims”. These structures are shown...

Unsupervised feature learning for autonomous rock image classification

Science.gov (United States)

Shu, Lei; McIsaac, Kenneth; Osinski, Gordon R.; Francis, Raymond

2017-09-01

Autonomous rock image classification can enhance the capability of robots for geological detection and enlarge the scientific returns, both in investigation on Earth and planetary surface exploration on Mars. Since rock textural images are usually inhomogeneous and manually hand-crafting features is not always reliable, we propose an unsupervised feature learning method to autonomously learn the feature representation for rock images. In our tests, rock image classification using the learned features shows that the learned features can outperform manually selected features. Self-taught learning is also proposed to learn the feature representation from a large database of unlabelled rock images of mixed class. The learned features can then be used repeatedly for classification of any subclass. This takes advantage of the large dataset of unlabelled rock images and learns a general feature representation for many kinds of rocks. We show experimental results supporting the feasibility of self-taught learning on rock images.

Dynamic features of bubble induced by a nanosecond pulse laser in still and flowing water

Science.gov (United States)

Charee, Wisan; Tangwarodomnukun, Viboon

2018-03-01

Underwater laser ablation techniques have been developed and employed to synthesis nanoparticles, to texture workpiece surface and to assist the material removal in laser machining process. However, the understanding of laser-material-water interactions, bubble formation and effects of water flow on ablation performance has still been very limited. This paper thus aims at exploring the formation and collapse of bubbles during the laser ablation of silicon in water. The effects of water flow rate on bubble formation and its consequences to the laser disturbance and cut features obtained in silicon were observed by using a high speed camera. A nanosecond pulse laser emitting the laser pulse energy of 0.2-0.5 mJ was employed in the experiment. The results showed that the bubble size was found to increase with the laser pulse energy. The use of high water flow rate can importantly facilitate the ejection of ablated particles from the workpiece surface, hence resulting in less deposition to the work surface and minimizing any disturbance to the laser beam during the ablation in water. Furthermore, a clean micro-groove in silicon wafer can successfully be produced when the process was performed in the high water flow rate condition. The findings of this study could provide an essential guideline for process selection, control and improvement in the laser micro-/submicro-fabrication using the underwater technique.

Lab-In-Syringe automation of stirring-assisted room-temperature headspace extraction coupled online to gas chromatography with flame ionization detection for determination of benzene, toluene, ethylbenzene, and xylenes in surface waters.

Science.gov (United States)

Horstkotte, Burkhard; Lopez de Los Mozos Atochero, Natalia; Solich, Petr

2018-06-22

Online coupling of Lab-In-Syringe automated headspace extraction to gas chromatography has been studied. The developed methodology was successfully applied to surface water analysis using benzene, toluene, ethylbenzene, and xylenes as model analytes. The extraction system consisted of an automatic syringe pump with a 5 mL syringe into which all solutions and air for headspace formation were aspirated. The syringe piston featured a longitudinal channel, which allowed connecting the syringe void directly to a gas chromatograph with flame ionization detector via a transfer capillary. Gas injection was achieved via opening a computer-controlled pinch valve and compressing the headspace, upon which separation was initialized. Extractions were performed at room temperature; yet sensitivity comparable to previous work was obtained by high headspace to sample ratio V HS /V Sample of 1.6:1 and injection of about 77% of the headspace. Assistance by in-syringe magnetic stirring yielded an about threefold increase in extraction efficiency. Interferences were compensated by using chlorobenzene as an internal standard. Syringe cleaning and extraction lasting over 10 min was carried out in parallel to the chromatographic run enabling a time of analysis of <19 min. Excellent peak area repeatabilities with RSD of <4% when omitting and <2% RSD when using internal standard corrections on 100 μg L -1 level were achieved. An average recovery of 97.7% and limit of detection of 1-2 μg L -1 were obtained in analyses of surface water. Copyright © 2018 Elsevier B.V. All rights reserved.

Tragacanth nanocapsules containing Chamomile extract prepared through sono-assisted W/O/W microemulsion and UV cured on cotton fabric.

Science.gov (United States)

Ghayempour, Soraya; Montazer, Majid

2017-08-15

Encapsulation is the best method to protect the plant extracts against volatility and instability in the presence of air, light, moisture and high temperatures. Nevertheless, application of encapsulated plant extracts on the textiles requires a low-temperature and high rate processing to avoid from breaking or destroying of capsules. The present paper represents application of nanocapsules prepared by ultrasound irradiation assisted W/O/W microemulsion method on the cotton fabric through UV curing method. The surface and structure of nanocapsules and treated cotton fabric using FESEM and FT-IR indicated the spherical nanocapsules with size of 60-80nm stabilized on the fabric surface in a film layer feature. Also, the treated cotton fabric showed a good release behavior of 96h, a high stability against washing and rubbing tests and a relative good antimicrobial activity with 91, 89 and 94% reduction against S. aureus, E. coli and C. albicans, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ion beam assisted deposition of nano-structured C:Ni films

Energy Technology Data Exchange (ETDEWEB)

Abrasonis, G.; Muecklich, A.; Heller, R.; Heinig, K.H.; Gemming, S.; Moeller, W. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Krause, M. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Institute of Physics, TU Dresden (Germany)

2012-07-01

Nanostructures influence material properties dramatically due to size, shape and interface effects. Thus the control of the structure at the nanoscale is a key issue in nanomaterials science. The interaction of hyperthermal ions with solids is confined to the nanometer scale. Thus, it can be used to control the morphology evolution during multiphase film deposition. Ion-induced displacements occur in a thin surface layer of the growing film where they increase the atomic mobility for the phase separation. Here the growth-structure relationship of C:Ni (15 at.%) nanocomposite films grown by oblique incidence (45 ) ion beam assisted deposition is reported. The influences of the flux of an assisting Ar+ ion beam (0-140 eV) as well as of an elevated substrate temperature have been studied. The formation of elongated nickel nanoparticles is strongly promoted by the ion beam assistance. Moreover, the metal nanocolumns no longer align with the advancing surface, but with the incoming ions. A window of conditions is established within which the ion assistance leads to the formation of regular composition modulations with a well defined periodicity and tilt. As the dominating driving force for the pattern formation is of physical origin, this approach might be applicable to other immiscible systems.

Electroencephalography (EEG) Based Control in Assistive Mobile Robots: A Review

International Nuclear Information System (INIS)

Krishnan, N Murali; Mariappan, Muralindran; Muthukaruppan, Karthigayan; Hijazi, Mohd Hanafi Ahmad; Kitt, Wong Wei

2016-01-01

Recently, EEG based control in assistive robot usage has been gradually increasing in the area of biomedical field for giving quality and stress free life for disabled and elderly people. This study reviews the deployment of EGG based control in assistive robots, especially for those who in need and neurologically disabled. The main objective of this paper is to describe the methods used for (i) EEG data acquisition and signal preprocessing, (ii) feature extraction and (iii) signal classification methods. Besides that, this study presents the specific research challenges in the designing of these control systems and future research directions. (paper)

Accessible surface area of proteins from purely sequence information and the importance of global features

Science.gov (United States)

Faraggi, Eshel; Zhou, Yaoqi; Kloczkowski, Andrzej

2014-03-01

We present a new approach for predicting the accessible surface area of proteins. The novelty of this approach lies in not using residue mutation profiles generated by multiple sequence alignments as descriptive inputs. Rather, sequential window information and the global monomer and dimer compositions of the chain are used. We find that much of the lost accuracy due to the elimination of evolutionary information is recouped by the use of global features. Furthermore, this new predictor produces similar results for proteins with or without sequence homologs deposited in the Protein Data Bank, and hence shows generalizability. Finally, these predictions are obtained in a small fraction (1/1000) of the time required to run mutation profile based prediction. All these factors indicate the possible usability of this work in de-novo protein structure prediction and in de-novo protein design using iterative searches. Funded in part by the financial support of the National Institutes of Health through Grants R01GM072014 and R01GM073095, and the National Science Foundation through Grant NSF MCB 1071785.

Oceanic whitecaps: Sea surface features detectable via satellite that ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

experiments that the air-sea gas transfer coefficient for each of a wide range of gases, including carbon dioxide and .... generators with which the basin was equipped, the .... whitecaps in air-sea gas exchange; Gas Transfer at Water. Surfaces ...

A self-assembled monolayer-assisted surface microfabrication and release technique

NARCIS (Netherlands)

Kim, B.J.; Liebau, M.; Huskens, Jurriaan; Reinhoudt, David; Brugger, J.P.

2001-01-01

This paper describes a method of thin film and MEMS processing which uses self-assembled monolayers as ultra-thin organic surface coating to enable a simple removal of microfabricated devices off the surface without wet chemical etching. A 1.5-nm thick self-assembled monolayer of

An image-processing methodology for extracting bloodstain pattern features.

Science.gov (United States)

Arthur, Ravishka M; Humburg, Philomena J; Hoogenboom, Jerry; Baiker, Martin; Taylor, Michael C; de Bruin, Karla G

2017-08-01

There is a growing trend in forensic science to develop methods to make forensic pattern comparison tasks more objective. This has generally involved the application of suitable image-processing methods to provide numerical data for identification or comparison. This paper outlines a unique image-processing methodology that can be utilised by analysts to generate reliable pattern data that will assist them in forming objective conclusions about a pattern. A range of features were defined and extracted from a laboratory-generated impact spatter pattern. These features were based in part on bloodstain properties commonly used in the analysis of spatter bloodstain patterns. The values of these features were consistent with properties reported qualitatively for such patterns. The image-processing method developed shows considerable promise as a way to establish measurable discriminating pattern criteria that are lacking in current bloodstain pattern taxonomies. Copyright © 2017 Elsevier B.V. All rights reserved.

Feature selection using genetic algorithms for fetal heart rate analysis

International Nuclear Information System (INIS)

Xu, Liang; Redman, Christopher W G; Georgieva, Antoniya; Payne, Stephen J

2014-01-01

The fetal heart rate (FHR) is monitored on a paper strip (cardiotocogram) during labour to assess fetal health. If necessary, clinicians can intervene and assist with a prompt delivery of the baby. Data-driven computerized FHR analysis could help clinicians in the decision-making process. However, selecting the best computerized FHR features that relate to labour outcome is a pressing research problem. The objective of this study is to apply genetic algorithms (GA) as a feature selection method to select the best feature subset from 64 FHR features and to integrate these best features to recognize unfavourable FHR patterns. The GA was trained on 404 cases and tested on 106 cases (both balanced datasets) using three classifiers, respectively. Regularization methods and backward selection were used to optimize the GA. Reasonable classification performance is shown on the testing set for the best feature subset (Cohen's kappa values of 0.45 to 0.49 using different classifiers). This is, to our knowledge, the first time that a feature selection method for FHR analysis has been developed on a database of this size. This study indicates that different FHR features, when integrated, can show good performance in predicting labour outcome. It also gives the importance of each feature, which will be a valuable reference point for further studies. (paper)

Breast cancer molecular subtype classifier that incorporates MRI features.

Science.gov (United States)

Sutton, Elizabeth J; Dashevsky, Brittany Z; Oh, Jung Hun; Veeraraghavan, Harini; Apte, Aditya P; Thakur, Sunitha B; Morris, Elizabeth A; Deasy, Joseph O

2016-07-01

To use features extracted from magnetic resonance (MR) images and a machine-learning method to assist in differentiating breast cancer molecular subtypes. This retrospective Health Insurance Portability and Accountability Act (HIPAA)-compliant study received Institutional Review Board (IRB) approval. We identified 178 breast cancer patients between 2006-2011 with: 1) ERPR + (n = 95, 53.4%), ERPR-/HER2 + (n = 35, 19.6%), or triple negative (TN, n = 48, 27.0%) invasive ductal carcinoma (IDC), and 2) preoperative breast MRI at 1.5T or 3.0T. Shape, texture, and histogram-based features were extracted from each tumor contoured on pre- and three postcontrast MR images using in-house software. Clinical and pathologic features were also collected. Machine-learning-based (support vector machines) models were used to identify significant imaging features and to build models that predict IDC subtype. Leave-one-out cross-validation (LOOCV) was used to avoid model overfitting. Statistical significance was determined using the Kruskal-Wallis test. Each support vector machine fit in the LOOCV process generated a model with varying features. Eleven out of the top 20 ranked features were significantly different between IDC subtypes with P machine-learning-based predictive model using features extracted from MRI that can distinguish IDC subtypes with significant predictive power. J. Magn. Reson. Imaging 2016;44:122-129. © 2016 Wiley Periodicals, Inc.

Automotive System for Remote Surface Classification.

Science.gov (United States)

Bystrov, Aleksandr; Hoare, Edward; Tran, Thuy-Yung; Clarke, Nigel; Gashinova, Marina; Cherniakov, Mikhail

2017-04-01

In this paper we shall discuss a novel approach to road surface recognition, based on the analysis of backscattered microwave and ultrasonic signals. The novelty of our method is sonar and polarimetric radar data fusion, extraction of features for separate swathes of illuminated surface (segmentation), and using of multi-stage artificial neural network for surface classification. The developed system consists of 24 GHz radar and 40 kHz ultrasonic sensor. The features are extracted from backscattered signals and then the procedures of principal component analysis and supervised classification are applied to feature data. The special attention is paid to multi-stage artificial neural network which allows an overall increase in classification accuracy. The proposed technique was tested for recognition of a large number of real surfaces in different weather conditions with the average accuracy of correct classification of 95%. The obtained results thereby demonstrate that the use of proposed system architecture and statistical methods allow for reliable discrimination of various road surfaces in real conditions.

On Feature Extraction from Large Scale Linear LiDAR Data

Science.gov (United States)

Acharjee, Partha Pratim

Airborne light detection and ranging (LiDAR) can generate co-registered elevation and intensity map over large terrain. The co-registered 3D map and intensity information can be used efficiently for different feature extraction application. In this dissertation, we developed two algorithms for feature extraction, and usages of features for practical applications. One of the developed algorithms can map still and flowing waterbody features, and another one can extract building feature and estimate solar potential on rooftops and facades. Remote sensing capabilities, distinguishing characteristics of laser returns from water surface and specific data collection procedures provide LiDAR data an edge in this application domain. Furthermore, water surface mapping solutions must work on extremely large datasets, from a thousand square miles, to hundreds of thousands of square miles. National and state-wide map generation/upgradation and hydro-flattening of LiDAR data for many other applications are two leading needs of water surface mapping. These call for as much automation as possible. Researchers have developed many semi-automated algorithms using multiple semi-automated tools and human interventions. This reported work describes a consolidated algorithm and toolbox developed for large scale, automated water surface mapping. Geometric features such as flatness of water surface, higher elevation change in water-land interface and, optical properties such as dropouts caused by specular reflection, bimodal intensity distributions were some of the linear LiDAR features exploited for water surface mapping. Large-scale data handling capabilities are incorporated by automated and intelligent windowing, by resolving boundary issues and integrating all results to a single output. This whole algorithm is developed as an ArcGIS toolbox using Python libraries. Testing and validation are performed on a large datasets to determine the effectiveness of the toolbox and results are

Correlation between Fatigue Crack Growth Behavior and Fracture Surface Roughness on Cold-Rolled Austenitic Stainless Steels in Gaseous Hydrogen

Directory of Open Access Journals (Sweden)

Tai-Cheng Chen

2018-03-01

Full Text Available Austenitic stainless steels are often considered candidate materials for use in hydrogen-containing environments because of their low hydrogen embrittlement susceptibility. In this study, the fatigue crack growth behavior of the solution-annealed and cold-rolled 301, 304L, and 310S austenitic stainless steels was characterized in 0.2 MPa gaseous hydrogen to evaluate the hydrogen-assisted fatigue crack growth and correlate the fatigue crack growth rates with the fracture feature or fracture surface roughness. Regardless of the testing conditions, higher fracture surface roughness could be obtained in a higher stress intensity factor (∆K range and for the counterpart cold-rolled specimen in hydrogen. The accelerated fatigue crack growth of 301 and 304L in hydrogen was accompanied by high fracture surface roughness and was associated with strain-induced martensitic transformation in the plastic zone ahead of the fatigue crack tip.

SVM-RFE based feature selection and Taguchi parameters optimization for multiclass SVM classifier.

Science.gov (United States)

Huang, Mei-Ling; Hung, Yung-Hsiang; Lee, W M; Li, R K; Jiang, Bo-Ru

2014-01-01

Recently, support vector machine (SVM) has excellent performance on classification and prediction and is widely used on disease diagnosis or medical assistance. However, SVM only functions well on two-group classification problems. This study combines feature selection and SVM recursive feature elimination (SVM-RFE) to investigate the classification accuracy of multiclass problems for Dermatology and Zoo databases. Dermatology dataset contains 33 feature variables, 1 class variable, and 366 testing instances; and the Zoo dataset contains 16 feature variables, 1 class variable, and 101 testing instances. The feature variables in the two datasets were sorted in descending order by explanatory power, and different feature sets were selected by SVM-RFE to explore classification accuracy. Meanwhile, Taguchi method was jointly combined with SVM classifier in order to optimize parameters C and γ to increase classification accuracy for multiclass classification. The experimental results show that the classification accuracy can be more than 95% after SVM-RFE feature selection and Taguchi parameter optimization for Dermatology and Zoo databases.

A multilevel-ROI-features-based machine learning method for detection of morphometric biomarkers in Parkinson's disease.

Science.gov (United States)

Peng, Bo; Wang, Suhong; Zhou, Zhiyong; Liu, Yan; Tong, Baotong; Zhang, Tao; Dai, Yakang

2017-06-09

Machine learning methods have been widely used in recent years for detection of neuroimaging biomarkers in regions of interest (ROIs) and assisting diagnosis of neurodegenerative diseases. The innovation of this study is to use multilevel-ROI-features-based machine learning method to detect sensitive morphometric biomarkers in Parkinson's disease (PD). Specifically, the low-level ROI features (gray matter volume, cortical thickness, etc.) and high-level correlative features (connectivity between ROIs) are integrated to construct the multilevel ROI features. Filter- and wrapper- based feature selection method and multi-kernel support vector machine (SVM) are used in the classification algorithm. T1-weighted brain magnetic resonance (MR) images of 69 PD patients and 103 normal controls from the Parkinson's Progression Markers Initiative (PPMI) dataset are included in the study. The machine learning method performs well in classification between PD patients and normal controls with an accuracy of 85.78%, a specificity of 87.79%, and a sensitivity of 87.64%. The most sensitive biomarkers between PD patients and normal controls are mainly distributed in frontal lobe, parental lobe, limbic lobe, temporal lobe, and central region. The classification performance of our method with multilevel ROI features is significantly improved comparing with other classification methods using single-level features. The proposed method shows promising identification ability for detecting morphometric biomarkers in PD, thus confirming the potentiality of our method in assisting diagnosis of the disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Employing Response Surface Methodology for the Optimization of Ultrasound Assisted Extraction of Lutein and β-Carotene from Spinach

Directory of Open Access Journals (Sweden)

Ammar Altemimi

2015-04-01

Full Text Available The extraction of lutein and β-carotene from spinach (Spinacia oleracea L. leaves is important to the dietary supplement industry. A Box-Behnken design and response surface methodology (RSM were used to investigate the effect of process variables on the ultrasound-assisted extraction (UAE of lutein and β-carotene from spinach. Three independent variables, extraction temperature (°C, extraction power (% and extraction time (min were studied. Thin-layer chromatography (TLC followed by UV visualization and densitometry was used as a simple and rapid method for both identification and quantification of lutein and β-carotene during UAE. Methanol extracts of leaves from spinach and authentic standards of lutein and β-carotene were separated by normal-phase TLC with ethyl acetate-acetone (5:4 (v/v as the mobile phase. In this study, the combination of TLC, densitometry, and Box–Behnken with RSM methods were effective for the quantitative analysis of lutein and β-carotene from spinach extracts. The resulting quadratic polynomial models for optimizing lutein and β-carotene from spinach had high coefficients of determination of 0.96 and 0.94, respectively. The optimal UAE settings for output of lutein and β-carotene simultaneously from spinach extracts were an extraction temperature of 40 °C, extraction power of 40% (28 W/cm3 and extraction time of 16 min. The identity and purity of each TLC spot was measured using time-of-flight mass spectrometry. Therefore, UAE assisted extraction of carotenes from spinach can provide a source of lutein and β-carotene for the dietary supplement industry.

Microwave-assisted RAFT polymerization of well-constructed magnetic surface molecularly imprinted polymers for specific recognition of benzimidazole residues

Science.gov (United States)

Chen, Fangfang; Wang, Jiayu; Chen, Huiru; Lu, Ruicong; Xie, Xiaoyu

2018-03-01

Magnetic nanoparticles have been widely used as support core for fast separation, which could be directly separated from complicated matrices using an external magnet in few minutes. Surface imprinting based on magnetic core has shown favorable adsorption and separation performance, including good adsorption capacity, fast adsorption kinetics and special selectivity adsorption. Reversible addition-fragmentation chain transfer (RAFT) is an ideal choice for producing well-defined complex architecture with mild reaction conditions. We herein describe the preparation of well-constructed magnetic molecularly imprinted polymers (MMIPs) for the recognition of benzimidazole (BMZ) residues via the microwave-assisted RAFT polymerization. The merits of RAFT polymerization assisting with microwave heating allowed successful and more efficient preparation of well-constructed imprinted coats. Moreover, the polymerization time dramatically shortened and was just 1/24th of the time taken by conventional heating. The results indicated that a uniform nanoscale imprinted layer was formed on the Fe3O4 core successfully, and enough saturation magnetization of MMIPs (16.53 emu g-1) was got for magnetic separation. The desirable adsorption capacity (30.18 μmol g-1) and high selectivity toward template molecule with a selectivity coefficient (k) of 13.85 of MMIPs were exhibited by the adsorption isothermal assay and competitive binding assay, respectively. A solid phase extraction enrichment approach was successfully established for the determination of four BMZ residues from apple samples using MMIPs coupled to HPLC. Overall, this study provides a versatile approach for highly efficient fabrication of well-constructed MMIPs for enrichment and determination of target molecules from complicated samples.

Clinical and Immunological Features of Opsoclonus-Myoclonus Syndrome in the Era of Neuronal Cell Surface Antibodies.

Science.gov (United States)

Armangué, Thaís; Sabater, Lidia; Torres-Vega, Estefanía; Martínez-Hernández, Eugenia; Ariño, Helena; Petit-Pedrol, Mar; Planagumà, Jesús; Bataller, Luis; Dalmau, Josep; Graus, Francesc

2016-04-01

Most studies on opsoclonus-myoclonus syndrome (OMS) in adults are based on small case series before the era of neuronal cell surface antibody discovery. To report the clinical and immunological features of idiopathic OMS (I-OMS) and paraneoplastic OMS (P-OMS), the occurrence of antibodies to cell surface antigens, and the discovery of a novel cell surface epitope. Retrospective cohort study and laboratory investigations of 114 adult patients with OMS at a center for autoimmune neurological disorders done between January 2013 and September 2015. Review of clinical records. Immunohistochemistry on rat brain and cultured neurons as well as cell-based assays were used to identify known autoantibodies. Immunoprecipitation and mass spectrometry were used to characterize novel antigens. Of the 114 patients (62 [54%] female; median age, 45 years; interquartile range, 32-60 years), 45 (39%) had P-OMS and 69 (61%) had I-OMS. In patients with P-OMS, the associated tumors included lung cancer (n = 19), breast cancer (n = 10), other cancers (n = 5), and ovarian teratoma (n = 8); 3 additional patients without detectable cancer were considered to have P-OMS because they had positive results for onconeuronal antibodies. Patients with I-OMS, compared with those who had P-OMS, were younger (median age, 38 [interquartile range, 31-50] vs 54 [interquartile range, 45-65] years; P OMS with lung cancer (21% vs 5% in patients with OMS without lung cancer; P = .02); however, a similar frequency of glycine receptor antibodies was found in patients with lung cancer without OMS (13 of 65 patients [20%]). A novel cell surface epitope, human natural killer 1 (HNK-1), was the target of the antibodies in 3 patients with lung cancer and P-OMS. Patients with I-OMS responded better to treatment and had fewer relapses than those with P-OMS. Older age and encephalopathy, significantly associated with P-OMS, are clinical clues suggesting an underlying tumor. Glycine receptor antibodies occur

Fabrication of TiO2/PU Superhydrophobic Film by Nanoparticle Assisted Cast Micromolding Process.

Science.gov (United States)

Li, Jie; Zheng, Jianyong; Zhang, Jing; Feng, Jie

2016-06-01

Lotus-like surfaces have attracted great attentions in recent years for their wide applications in water repellency, anti-fog and self-cleaning. This paper introduced a novel process, nanoparticle assisted cast micromolding, to create polymer film with superhydrophobic surface. Briefly, waterborne polyurethane (WPU) sol and nano TiO2/WPU sol were each cast onto the featured surfaces of the poly(dimethylsiloxane) (PDMS) stamps replicated from fresh lotus leaves. After being dried and peeled off from the stamps, PU and TiO2/WPU replica films were created respectively. To the former, only high hydrophobic property was observed with static water contact angle (WCA) at 142.5 degrees. While to the later, superhydrophobic property was obtained with WCA more than 150 degrees and slide angle less than 3 degrees. Scanning electron microscopy (SEM) imaging showed that the PU replica film only had the micro-papillas and the TiO2/PU replica film not only had micro papillas but also had a large number of nano structures distributed on and between the micro-papillas. Such nano and micro hierarchical structures were very similar with those on the natural lotus leaf surface, thus was the main reason for causing superhydrophobic property. Although an elastic PDMS stamp from lotus leaf was used in herein process, hard molds may also be used in theory. This study supplied an alternative technique for large scale production of polymeric films with superhydrophobic.

Microwave and plasma-assisted modification of composite fiber surface topography

Science.gov (United States)

Paulauskas, Felix L [Knoxville, TN; White, Terry L [Knoxville, TN; Bigelow, Timothy S [Knoxville, TN

2003-02-04

The present invention introduces a novel method for producing an undulated surface on composite fibers using plasma technology and microwave radiation. The undulated surface improves the mechanical interlocking of the fibers to composite resins and enhances the mechanical strength and interfacial sheer strength of the composites in which they are introduced.

Ultrasonic-Assisted Extraction and Antioxidant Activity of Flavonoids ...

African Journals Online (AJOL)

Purpose: To identify the main flavonoid in Adinandra nitida leaf, employ response surface methodology to optimize its ultrasonic-assisted extraction, and determine the antioxidant activity of the obtained extract. Methods: The main flavonoid in Adinandra nitida leaf was obtained by traditional solvent extraction and ...

Hyperspectral image classifier based on beach spectral feature

International Nuclear Information System (INIS)

Liang, Zhang; Lianru, Gao; Bing, Zhang

2014-01-01

The seashore, especially coral bank, is sensitive to human activities and environmental changes. A multispectral image, with coarse spectral resolution, is inadaptable for identify subtle spectral distinctions between various beaches. To the contrary, hyperspectral image with narrow and consecutive channels increases our capability to retrieve minor spectral features which is suit for identification and classification of surface materials on the shore. Herein, this paper used airborne hyperspectral data, in addition to ground spectral data to study the beaches in Qingdao. The image data first went through image pretreatment to deal with the disturbance of noise, radiation inconsistence and distortion. In succession, the reflection spectrum, the derivative spectrum and the spectral absorption features of the beach surface were inspected in search of diagnostic features. Hence, spectra indices specific for the unique environment of seashore were developed. According to expert decisions based on image spectrums, the beaches are ultimately classified into sand beach, rock beach, vegetation beach, mud beach, bare land and water. In situ surveying reflection spectrum from GER1500 field spectrometer validated the classification production. In conclusion, the classification approach under expert decision based on feature spectrum is proved to be feasible for beaches

Quadrilateral mesh fitting that preserves sharp features based on multi-normals for Laplacian energy

Directory of Open Access Journals (Sweden)

Yusuke Imai

2014-04-01

Full Text Available Because the cost of performance testing using actual products is expensive, manufacturers use lower-cost computer-aided design simulations for this function. In this paper, we propose using hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. We propose automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fit the surface of the voxels to the target surface using Laplacian energy minimization. We used normal vectors in the fitting to preserve sharp features. However, this method could not represent concave sharp features precisely. In this proposal, we improve our previous Laplacian energy minimization by adding a term that depends on multi-normal vectors instead of using normal vectors. Furthermore, we accentuate a convex/concave surface subset to represent concave sharp features.

Functionalization of glassy carbon surface by means of aliphatic and aromatic amino acids. An experimental and theoretical integrated approach

International Nuclear Information System (INIS)

Vanossi, Davide; Benassi, Rois; Parenti, Francesca; Tassinari, Francesco; Giovanardi, Roberto; Florini, Nicola; De Renzi, Valentina; Arnaud, Gaelle; Fontanesi, Claudio

2012-01-01

Highlights: ► Glassy carbon is functionalized via electrochemical assisted grafting of amino acids. ► The grafting mechanism is suggested to involve the “zwitterionic” species. ► DFT calculations allowed to determine the electroactive species. ► An original grafting mechanism is proposed. - Abstract: Glassy carbon (GC) electrode surfaces are functionalized through electrochemical assisted grafting, in oxidation regime, of six amino acids (AA): β-alanine (β-Ala), L-aspartic acid (Asp), 11-aminoundecanoic acid (UA), 4-aminobenzoic acid (PABA), 4-(4-amino-phenyl)-butyric acid (PFB), 3-(4-amino-phenyl)-propionic acid (PFP). Thus, a GC/AA interface is produced featuring carboxylic groups facing the solution. Electrochemical (cyclic voltammetry and electrochemical impedance spectroscopy) and XPS techniques are used to experimentally characterize the grafting process and the surface state. The theoretical results are compared with the experimental evidence to determine, at a molecular level, the overall grafting mechanism. Ionization potentials, standard oxidation potentials, HOMO and electron spin distributions are calculated at the CCD/6-31G* level of the theory. The comparison of experimental and theoretical data suggests that the main electroactive species is the “zwitterionic” form for the three aliphatic amino acids, while the amino acids featuring the amino group bound to the phenyl aromatic moiety show a different behaviour. The comparison between experimental and theoretical results suggests that both the neutral and the zwitterionic forms are present in the acetonitrile solution in the case of 4-(4-amino-phenyl)-butyric acid (PFB) and 3-(4-amino-phenyl)-propionic acid.

Contact area measurements on structured surfaces

DEFF Research Database (Denmark)

Kücükyildiz, Ömer Can; Jensen, Sebastian Hoppe Nesgaard; De Chiffre, Leonardo

In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means.......In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means....

Internal Physical Features of a Land Surface Model Employing a Tangent Linear Model

Science.gov (United States)

Yang, Runhua; Cohn, Stephen E.; daSilva, Arlindo; Joiner, Joanna; Houser, Paul R.

1997-01-01

The Earth's land surface, including its biomass, is an integral part of the Earth's weather and climate system. Land surface heterogeneity, such as the type and amount of vegetative covering., has a profound effect on local weather variability and therefore on regional variations of the global climate. Surface conditions affect local weather and climate through a number of mechanisms. First, they determine the re-distribution of the net radiative energy received at the surface, through the atmosphere, from the sun. A certain fraction of this energy increases the surface ground temperature, another warms the near-surface atmosphere, and the rest evaporates surface water, which in turn creates clouds and causes precipitation. Second, they determine how much rainfall and snowmelt can be stored in the soil and how much instead runs off into waterways. Finally, surface conditions influence the near-surface concentration and distribution of greenhouse gases such as carbon dioxide. The processes through which these mechanisms interact with the atmosphere can be modeled mathematically, to within some degree of uncertainty, on the basis of underlying physical principles. Such a land surface model provides predictive capability for surface variables including ground temperature, surface humidity, and soil moisture and temperature. This information is important for agriculture and industry, as well as for addressing fundamental scientific questions concerning global and local climate change. In this study we apply a methodology known as tangent linear modeling to help us understand more deeply, the behavior of the Mosaic land surface model, a model that has been developed over the past several years at NASA/GSFC. This methodology allows us to examine, directly and quantitatively, the dependence of prediction errors in land surface variables upon different vegetation conditions. The work also highlights the importance of accurate soil moisture information. Although surface

Dilution rate and microstructure of TIG arc Ni-Al powder surfacing layer

Institute of Scientific and Technical Information of China (English)

SHAN Jiguo; DONG Wei; TAN Wenda; ZHANG Di; PEN Jialie

2007-01-01

Surfacing beads are prepared by a direct current tungsten inert gas arc nickel-aluminum (Ni-Al) powder surfacing process. With the aim of controlling the dilution rate and obtaining surfacing beads rich in intermetallic compounds, the effects of surfacing parameters on geometric parameters, dilution rate, composition, and microstructure of the bead are investigated. An assistant cooler, which can potentially reduce the temperature of the base metal, is used in the surfacing process and its effect on dilution rate and microstructure is studied. The result indicates that with the surfacing parameter combination of low current and speed, the width and penetration of the bead decrease, reinforcement increases, and dilution rate drops markedly. With the reduc- tion of the parameter combination, the intergranular phase T-(Fe, Ni) is formed in the grain boundaries of Ni-Al interme- tallic matrix instead of the intergranular phase α-Fe, and large amount of intermetallics are obtained. With the use of an assistant cooler on a selected operation condition during the surfacing process, the reinforcement of the bead increases, penetration decreases, and dilution rate declines. The use of an assistant cooler helps obtain a surfacing bead composed of only intermetallics.

Feature-Sensitive Tetrahedral Mesh Generation with Guaranteed Quality

OpenAIRE

Wang, Jun; Yu, Zeyun

2012-01-01

Tetrahedral meshes are being extensively used in finite element methods (FEM). This paper proposes an algorithm to generate feature-sensitive and high-quality tetrahedral meshes from an arbitrary surface mesh model. A top-down octree subdivision is conducted on the surface mesh and a set of tetrahedra are constructed using adaptive body-centered cubic (BCC) lattices. Special treatments are given to the tetrahedra near the surface such that the quality of the resulting tetrahedral mesh is prov...

Assistance for design and realization of real-time safety critical applications according to Oasis

International Nuclear Information System (INIS)