bluuebunny/crossref_metadata_2025 huggingface dataset:
Cold Roll Cladding of Carbon Steels
Authors: Etzlstorfer Christoph , Leitner Alois , Arenholz Enno , Kozeschnik Ernst
Published: June 2019

Cladding of steel is mainly carried out by hot rolling. This process is very labor-intensive and, therefore, expensive. Cold plating has been used successfully to produce bimetals and could also be an alternative manufacturing process for cladded carbon steel composites. So far, however, only thin narrow IF-steels sheets were successfully cold plated. Different pretreatments and process windows have been used to successfully produce a cold roll-cladded composite of various steel grades on a cold rolling test facility. While joining two similar steels was relatively easy, the combination of different steel alloy compositions was more difficult. Higher necessary forces and edge cracks complicated the experiments. A slight warming of the sheets before joining had a positive effect on the production of the composite. From today's perspective, the required high rolling forces do not allow scaling up to large-scale production.
Heat Exchange Structures Based on Copper/CNT Composite
Authors: Schlott André , Hutsch Thomas , Hampel Silke , Lohse Julius , Weißgärber Thomas , Kieback Bernd
Published: June 2019

In this study different types of multi-walled carbon nanotubes (MWCNT) were produced by the fixed bed and aerosol chemical vapor deposition (CVD) method. Nanocomposite materials were prepared by incorporation of different MWCNTs in copper matrix using powder metallurgy methods. By using hot pressing in combination with hot extrusion, the orientation of the carbon reinforcement was tuned from 3D to 1D alignment. After a selective etching process the carbon reinforcement is partially free-standing at the composite surface, but still embedded in the metal matrix. The engineered surface acts almost like a black body. The spectral evaluation of the surface functionalization will be shown for wavelengths from 200 nm to 20 µm. These results are compared to bulk copper. The free-standing MWCNT also behave like fins/pins in heat exchanger structures or surface enhancement in pool boiling. The experimental setup will be explained and the measurement described for pure copper. The theoretical heat transfer coefficient of the engineered surface is calculated depending on diameter and length of the free-standing MWCNTs. The results are compared to bulk copper.
Investigation of Statistical Distribution of C/C-SiC Composite’s Mechanical Properties
Authors: Shi Yuan , Xiu Yan Lei , Koch Dietmar
Published: June 2019

Because of the excellent fracture toughness and oxidation resistance, carbon fiber reinforced silicon carbide (C/C-SiC or C/SiC) exhibits a sound potential in various application areas such as aerospace technology and high-performance braking systems. For the composite’s reliable design, production, examination, quality assurance and verification, however, the statistical distribution of mechanical properties is of crucial interest and has not been investigated in detail yet. In this work, the strength values of C/C-SiC composite, which was developed via Liquid Silicon Infiltration at the Institute of Structures and Design of German Aerospace Center (DLR), were measured under tensile, bending and compression load. The results were analyzed by normal and Weibull distribution statistics and verified by Kolmogorov–Smirnov-test (KS-test) and Anderson–Darling-test (AD-test). Based on the statistical analysis, the 4PB-strength of C/C-SiC composite can be better described by Weibull distribution. In comparison, normal distribution is more suitable for the compression strength. The influence of different numbers of coupons on the mechanical properties has been identified. A scanning electron microscope (SEM) was employed to analyze the fracture surface, which confirmed that the different statistical distribution of strength values was caused by various failure mechanisms.
Thermoplastic Multi-Material Nonwovens from Recycled Carbon Fibres Using Wet-Laying Technology
Authors: Sauer Michael , Feil Jonas , Manis Frank , Betz Tobias , Drechsler Klaus
Published: June 2019

In this study, multi-material nonwovens were produced using a wet laying nonwoven batch process. The aim of this work is to investigate and develop nonwoven material solutions that can be used for a substitution of pure glass fibre (GF)-applications and also provide a more cost-sensitive option compared to nonwovens purely made from recycled carbon fibres (rCF). The multi-material-nonwovens of this study consisted of the functional components rCF and GF as well as a thermoplastic matrix, built by the admixture of PA6-fibres. All three fibre types were mixed directly within the nonwoven manufacturing process, respectively in the course of the initial weighed portions. Six different material compositions with individual amounts of rCF and GF were produced, but a constant overall fibre volume content (FVC) as well as a uniform grammage was defined. A hot pressing technique was used to consolidate these multi-material-nonwoven layers. Subsequently, the sheet materials were examined using tensile and 4-point bending tests, as well as wet-chemical fibre volume content determinations and micrographic sections. With regard to the mechanical performance, a near-linear increase is observed for increased proportions of recycled carbon fibres. In this context a potential for the use of multi-material-nonwovens consisting of rCF and GF can be found. It is demonstrated that rCF might be an adequate substituent for classical GF-applications. The results contribute to broadening the performance spectrum of rCF and thus to its substantial recycling route.
Temperature Dependency of the Deformation Behavior of Hybrid CFRP/Elastomer/Metal Laminates under 3-Point Bending Loads
Authors: Sessner Vincent , Weidenmann Kay André
Published: June 2019

Fibre-metal-elastomer laminates offer the possibility of using material combinations which often have to deal with premature delamination, for example due to different coefficients of thermal expansion or galvanic corrosion due to different electronegativities. The present study deals with laminates made of layers of CFRP and aluminum, each of which is bonded together by an elastomer layer. The shear-soft elastomer also allows the much stiffer aluminum and CFRP layers to be sheared off against each other under bending stress. This leads to complex deformation behavior. The shear of the elastomer also plays a crucial role in the damping behavior of the laminate. Due to large shear deformations in the elastomer layer, the combination of rigid layers and soft elastomer layers shows very good damping behavior according to the principle of constrained layer damping. Since bending vibrations that occur during normal use usually have only small amplitudes, the deformation behavior is of particular interest in the elastic range. Since this deformation behavior is strongly dependent on the shear modulus of the elastomer used and this in turn is strongly influenced by temperature, the deformation behavior is characterized at different temperatures. Within the scope of this investigation, quasi-static 3-point bending tests are carried out on different laminate lay-ups in the temperature range from -40 °C to +80 °C. The laminates are consolidated by compression molding and contain two different EPDM elastomers in varying layer thicknesses, unidirectional CFRP prepreg in biaxial layer lay-up and aluminum 2024 sheets. The deformation behavior is analyzed by digital image correlation. This is used to measure both the bending line of the overall composite and strains over the layer thickness. In particular, the shear in the elastomer layers is evaluated and set in relation to the bending lines. Finally, the ability of the laminate lay-up to damp bending vibrations is evaluated.
Polymer-Steel-Sandwich-Structures: Influence of Process Parameters on the Composite Strength
Authors: Lohr Christoph , Muth Markus , Dreher Ralf , Zinn Carolin , Elsner Peter , Weidenmann Kay André
Published: June 2019

As the demand of the automotive and aerospace industries for lightweight and cost effective materials increases, it is necessary to combine different materials with respect to their lightweight and functional properties. The combination of polymer-steel-sandwich composites - which consist of a polymer core structure (transferring shear loads) and two metal face-layers (absorbing tensile and compression loads occurring at bending) - suite the need of minimizing weight per area under bending loads. The reduction of process steps can be achieved by connecting the face layers and core in-situ via an in-mold assembly process using variothermal processing. The injection mold hereby is heated near the melt temperature of the polymer with a variothermal water processing unit. Via contact heating inserted steel blanks are heated to the same temperature as the mold. This process enables the combination of the metal surface with the polymer core by infiltrating the micro or nano scale structure, which is generated by laser structuring or nano coating. Through the increased mold/blank surface temperature induced via variothermal heating the melt viscosity is lowered. This decreasing viscosity of the polymer melt hereby enables a higher degree of infiltration of the laser structured and nano coated blanks. This improved infiltration behavior is a key factor for the adhesion of the sandwich components and beneficial for the composites strength. Within this work two steel blanks are inserted into the mold to manufacture sandwich structures with steel face layers and a polymer (here: polylactidacid; PLA) core. As these sandwich composites are prone to bending failure, the 4-point-bending test is used to characterize the mechanical properties of this hybrid structure. The two surface treatments will also be compared concerning their mechanical interface properties with a shear edge test. The additional reduction on the polymer melt viscosity by means of gas inducing with chemical blowing agent is investigated on the laser structured surfaces only. To investigate the influence of the polymers melts viscosity on the bonding properties chemical blowing agent is added for some blanks.
Analysis of a Process Approach for Production of Triaxial Braids with Locally Customized Filler Yarn Count
Authors: Eschler Eric , Hüls Julius , Zaremba Swen , Drechsler Klaus
Published: June 2019

In order to enhance lightweight potential and fabrication efficiency of structural parts from carbon fiber-reinforced plastics, the approach of locally tailored component properties has proven effective. For braided hollow profiles, however, technical possibilities to achieve process integrated adaption of a components’ mechanical properties are limited. Therefore, a novel braiding process approach for cycle-time-neutral adjustment of a triaxial braids filler yarn count is examined and its advantages for component design are illustrated. The main objective of this study is to evaluate the approaches applicability with regard to process stability and disturbance of product quality. Two consecutive test series are carried out to identify the most influential process variables and to link the variation of these variables with multiple criteria of process quality. A clear dependency between quality and braid angle, braid yarn tension as well as the number of filler yarns the approach is applied on is derived. On that basis a set of process variables for faultless application of the concept is pointed out.
Material Characterization and Compression Molding Simulation of CF-SMC Materials in a Press Rheometry Test
Authors: Schommer Dominic , Duhovic Miro , Romanenko Vitali , Andrä Heiko , Steiner Konrad , Schneider Matti , Hausmann Joachim M.
Published: June 2019

The compression molding of sheet molding compounds (SMCs) is typically thought of as a fluid mechanics problem. The usage of CF-SMC with high fiber volume content (over 50%) and long fiber reinforcement structures (up to 50 mm) challenges the feasibility of this point of view. In this work a user-defined material model based on a solid mechanics formulation is developed in LS-DYNA®. The material model is built on a modular principle where the different influence factors caused by the material characteristics form building blocks. The idea is that these blocks are represented by simple mathematical models and interact in a way that forms the overall behavior of the SMC material. To analyze the behavior of the SMC material and create input parameters for the material model it is necessary to perform some kind of material characterization experiment. This paper presents the press rheometry test which can be perform in two variations, differing in terms of specimen size and shape and degree of coverage in the tool. Here the material response to the compression molding can be analyzed and by the visualization of the flow front development the anisotropy and homogeneity of the material can be assessed. For a comparison between the material model and reality the two variations of the press rheometry test are simulated. The simulation results show a good prediction of the experiments. The differences between experiment and simulation can be used to further improve the model in a later process.
A Novel Simulative-Experimental Approach to Determine the Permeability of Technical Textiles
Authors: Schmidt Tim , Schimmer Florian , Widera Aaron , May David , Motsch Nicole , Bauer Constantin
Published: June 2019

Since years, fiber reinforced polymer composite (FRPC) parts made by Liquid composite molding (LCM) make up a significant share of the composite market. In LCM dry reinforcing structure gets impregnated with a resin system. Permeability, a material parameter with key influence on all LCM processes, quantifies the conductance of technical textiles for resin flow. Today, when a numerical filling simulation is applied for process design, large experimental test programs are required for characterization of permeability, as the permeability has to be measured for all textiles processed and also the dependency e.g. on the fiber volume content has to be considered. Together with Math2Market GmbH (M2M), the IVW currently develops a novel simulative-experimental approach (SEA), using experimental tests to calibrate a simulation model for replacing a significant amount of the experimental tests through “virtual” measurements. In a first step the functionality of the simulation and the most appropriate methods for textile modelling were investigated. For this, three routes were followed: At first a micro-computer tomograph (μCT)-scan of a glass fiber non-crimp fabric was fed into GeoDict, the material simulation software developed by M2M. Second, a digital model (DM) of the textile was created by computer modelling of basic structure and subsequent virtual compaction. μCT-model and DM were then used for computational fluid flow simulation which gives the direction-dependent permeability as an output. The DM calibrated by experiments represents the SEA and results in the digital twin. Third route was the experimental permeability measurement to generate reference values. Comparing the results of all three routes allows statements about the functionality of the simulation and accuracy of modelling. The rather deficient correlation between the results of experiments and μCT-model based simulations revealed that segmentation is a remarkable source of error despite the use of recognized methods. Different modeling approaches were followed to build up the digital twin. The best results were achieved with models undergoing a virtual compaction step, which takes various imperfections such as yarn deformation and varying nesting behavior into account. With this 2.25 - 6.75% deviation from the experimental results at an average standard deviation of 21.9 - 61.2% were achieved. Hence, the digital twin shows a better correlation than the μCT-model and high potential for substitution of experiments. Even better results are expected when in a next step a local anisotropic permeability will be allocated to the yarns.
Sensitivity Study of Material Input Data on FE Forming Results for Wrinkling and Shearing of Fiber Reinforced Thermoplastic Parts
Authors: Engel Bernd , Graef Jasmin
Published: June 2019

This work presents the analysis of the influence of several material input data to the FE results of the forming process of fiber reinforced thermoplastics within a sensitivity study. The *Fabric material model of Abaqus/Explicit is used for the description of the shear, tensile and compression behavior. It is a test-data based model. The bending behavior will be modeled with beam elements. The interaction between input data will be analyzed and its influence onto the FE forming results and FE analysis of material tests like bias-extension-test, compression and bending test with focus on interactions of input data and test procedure itself.
Development of a Novel Textile Process for the Production of Highly Oriented Nonwovens Made from Recycled Carbon Fibres
Authors: Petrich Michael , Hoffmeister Christoph , Herrmann Axel
Published: June 2019

Carbon fibre reinforced plastics (CRFP) are high performance materials with an outstanding lightweight potential. Recycling applications for production waste though, are still scarce and not fully established. In the CaroLIn (carbon fibre nonwovens optimised for aircraft interior components) research project a novel aerodynamic textile process is developed, in order to produce highly orientated non-wovens form recycled carbon fibres. In the first stage of the project a laboratory plant for the orientation of fibres has been constructed and implemented. Afterwards a process window has been defined and a number of process parameters identified. The influence of those parameters was then investigated, using the statistical design of experiment (DOE) method.
Novel Lightweight Semi-Finished Products Made of Poplar Veneer Plywood with Basalt Fibre Reinforcement
Authors: Tautenhain Florian , Rinberg Roman , Kroll Lothar
Published: June 2019

Veneer plywood is established in building construction, interior finishing and vehicle construction. Particularly in automotive or ship interior applications, the requirements with regard to strength and stiffness properties are increasing. At the same time, the weight of the panel materials used is to be reduced. The development presented here is a new type of lightweight basalt fibre-reinforced poplar veneer plywood and at the same time rigid alternative to the established birch veneer plywood. By adapting the adhesive and the reinforcing semi-finished products, the material and manufacturing costs are comparatively low. The bonding of the fibre reinforcement to the carrier material is achieved by means of adapted wood adhesives (e.g. polyvinyl acetates), which are also used as matrix material for the fibre reinforcement. An application of the reinforcement layer is integrated into the coating process (e.g. with High Pressure Laminate HPL decorative fabrics) of the carrier material. Essential advantages compared to conventional board materials are shown in this paper. The research results were achieved at the Institute for Structural Lightweight Construction of the TU Chemnitz in cooperation with the company Toms Gerber GmbH within the ZiM cooperation project FuBa.
Investigation of the Creep Resistance of a Spray-Compacted Si-Particle Reinforced Al-Based MMC (Dispal® S270)
Authors: Tetzlaff Ulrich , Gerber Alexander , Amelang Rudolf , Lemos Georges
Published: June 2019

MMCs exhibit a high potential in modern structures due to many positive attributes. One of these attributes is a heightened creep resistance compared to conventional single or multi-phase alloys. The following paper focuses on the creep resistance of a spray-compacted Al-based alloy (DISPAL® S270). This alloy, designed for high temperature applications like turbochargers, cylinder bore liners or pistons can be subjected to temperatures up to 450°C, which is considerably higher compared to unreinforced Al-alloys. DISPAL® S270 microscopically consists of Si-particles with round shapes in an Al-rich α solid solution, which is additionally reinforced by complex precipitates, including Al9FeNi and Al3Ti, among others. The particle sizes and ratios differ with the heat treatment. The same applies to the precipitates in the matrix. The investigated heat treatments are F (after extrusion) and T6 (additional peak aged). The alloy is tested at 250°C using different loads at constant force with stress values between 125 and 200 MPa. The measured minimal creep rates are in the range of min. = 10-5-10-8 1/s. In comparison to conventional single or multiple phase alloys MMCs reveal some advantages, since the modified threshold stresses and direct strengthening often reduce the minimum creep rate. The stress exponent of the MMCs has higher values ​​compared to aluminum alloys, as known from previous MMC studies. The specimens are analyzed with LM, SEM, EDS and XRD. It could be shown that an additional heat treatment (peak aged T6) enhances the creep properties by introducing very fine precipitates containing the Mg5Si6 phase.
High-Performance Copolymerized Poly(m-Phenylene Isophthalamide) (PMIA) Fibers Containing Ether Moiety: Preparation, Structure and Properties
Authors: Li Na , Zhang Xing Ke , Yu Jun Rong , Wang Yan , Zhu Jing , Hu Zu Ming
Published: June 2019

Copolymerized poly (m-phenylene isophthalamide) (co-PMIA) fibers with excellent thermal stability and good mechanical properties were developed via solution polycondensation process based on m-phenylenediamine (MPD), isophthaloyl dichloride (IPC), and 3,4′-oxydianiline (3,4′-ODA). Effects of the ether moiety on the structure and properties of the copolymers were investigated. A series of co-PMIA nascent fibers were produced using wet-spinning method. The coagulation process to form co-PMIA nascent fibers were studied by examination of SEM and strength tester. The co-PMIA nascent fibers with the MPD/3,4′-ODA molar ratio of 8:2 showed an optimum dye uptake. Keywords: Copolymerization; High performance material; Wet spinning; Dyeability.
Superhydrophobic Surface Modified by Sol-Gel Silica Nanoparticle Coating
Authors: Zhang Xiao Xing , Wang Yan Yan , Gu Liang , Xu Zhi Yong , Liu Yan Hua , Peng Chang Si
Published: June 2019

We reported a superhydrophobic silica-coated surface with a water contact angle of 160° with a 4 μL water droplet, and transparency of 70-86% in the wavelength range of 380-800 nm. The silica film was synthesized at room temperature (22 °C) using sol-gel process by a simple, cost-effective and uniform spin-coating by mixing silicon dioxide sol-gel with γ-(2, 3-epoxypropyloxy) propyltrimethoxysilane (KH-560). The durability of the coating could be effectively enhanced by controlling the ratio of KH-560 and modified silicon dioxide sol-gel. It was believed that this process that we used can hold a great potential in super-hydrophobic surface fabrication.
Research on Thermal Aging Characteristics and Mechanism of the Silicon Rubber Insulation Layer of Cable Joints
Authors: Li Yong Lan , Qiu Man Shi , Ma Jia Wei , Kuang Guo Wen , Gao Nai Kui , Jin Hai Yun , Yu Xin
Published: June 2019

In order to solve the thermal aging problem of silicone rubber insulation layer of 220 kV integral prefabricated cable joints, the mass loss and thermal gravimetric (TG) were tested. The thermal aging mechanism of thermal degradation reaction of silicone rubber molecular chains was analyzed by gel content test and infrared spectrum test (IR). The results showed that the cross-linked network of the molecular chain structure gradually deteriorates, resulting in the increase of mass loss rate and the decrease of thermal stability. The results also showed that the increase of dual peak of differential thermal weight (DTG), the decrease of initial decomposition temperature and the remaining mass. With increasing aging temperature and aging time, the aging would be accelerated. These properties could reflect the degree of thermal aging of silicone rubber insulation layer. The results could also provide theoretical support for the preparation, operation and maintenance for silicone rubber cable joints.
Improved Electrochemical Performance of Nd3+- Doped LiNi0.5Mn1.5O4 Cathode Material for 5 V Lithium-Ion Batteries
Authors: Wei Ai Jia , Li Wen , Zhang Li Hui , Liu Zhen Fa
Published: June 2019

Spinel powders of Nd-doped LiNi0.5NdxMn1.5−xO4 with different Nd3+ contents (x = 0, 0.01, and 0.02) have been synthesized by a solid-state ball milling method. The samples was characterized by XRD, SEM and EDS. XRD shows the doping of Nd3+ did not destroy the formation of spinel LNMO.The results show that LiNi0.5Nd0.01Mn1.49O4 sample exhibits a higher rate performance with specific discharge capacities of 134.8, 137.2, 136.5, 130.4, 123.8, 106.4, and 83.1 mAh g−1 at 0.2, 0.5, 1, 2, 3, 5, and 7 C (1 C = 140 mAh g−1), respectively. The results indicate that the Nd3+ doping could reduce the electrode polarization and enhance the rate capacities.
Processing of High Purity Titanium by Equal Channel Angular Pressing at Cryogenic Temperature
Authors: Wang Hong Fei , Liu Si Tong , Ban Chun Yan , Zhao Nan Nan , Kang Yi Yao , Qin Ti Peng , Cui Jian Zhong
Published: June 2019

Experiments show that high purity titanium (HP-Ti) samples have been successfully processed by equal channel angular pressing (ECAP) using a 120 degree die and a relatively slow ram speed at cryogenic temperature when the HP-Ti rods were trapped with 6061 Al alloy tubes. Optical microscopy (OM) and transmission electron microscopy (TEM) were utilized to investigate the deformed microstructure of the material. Typical microstructures of shear bands and deformation twinning were found in the deformed microstructure of ECAPed HP-Ti. Furthermore, the SAED pattern analysis of the twinning structures revealed that the deformation twinning occurred on {112} planes. Keywords: High purity titanium; ECAP; TEM; Deformation twinning; Cryogenic temperature.
Adjacent segment degeneration and topping off. Never stop at the apex!
Authors: Konieczny Markus R. , Mokhaberi Shejda , Krauspe Rüdiger
Published: June 2019

We investigated if applying the Transition system (® Globus Medical) as topping off can prevent Adjacent Segment Degeneration (ASD) and if rate of ASD is increased if instrumentation stopped at the apex of the Lumbar Lordosis (LL). We enrolled 99 consecutive patients in a retrospective study who have been operated by instrumented fusion of the lumbar spine. Thirty patients were treated by topping of (Group 1), 69 patients received the standard procedure (Group 2). 18 patients of group 1 (60%) and 38 patients of group 2 (55%) developed ASD. The difference was not significant (p>0.05). In 17 patients (17%) instrumentation stopped at apex of LL. 14/17 patients (82%) developed an ASD. This influence was significant (p<0.05). Instrumented fusion of the lumbar spine should not stop at the apex of the lumbar curve. Topping off by hybrid dynamic fixation does not reduce the rate of ASD.
Evaluando el desempeño de índices espectrales para identificar humedales alto andinos
Authors: Aponte-Saravia J. , Ospina-Noreña J. E.
Published: June 2019

High Andean wetlands are habitats critical to life forms that have adapted to these extreme high mountain ecosystems, and for living beings that inhabit the lower parts of the basin; they are spaces that contain high diversity of flora and fauna characteristic of these places and are strongly associated with the water component. There lies the importance of identifying and monitoring ecosystems, using easy applicable methods and allowing results every two weeks approximately, they are inexpensive and highly reliable. Methods of monitoring in short periods, they are economically profitable and provide reliable information, they correspond to the evaluations by satellite images, specifically applying the methods of spectral indices. Thereby, the objective of the research was to evaluate the performance of six indices, considered to be the most used to identify high Andean wetlands (humidity index at surface level, normalized difference water index, normalized difference vegetation index, enhanced vegetation index, index of vegetation to the surface and tasseled CAP vegetation), in periods of low precipitation, using imagery Landsat 8 OLI. Comparing the performance of those indexes in the identification of wetlands through cross-validation and bootstrap statistical learning, the index that showed better performance was tasseled CAP vegetation, revealing the lowest value of the average of the mean square error of iterations between the test failure rate and training. The index tasseled CAP vegetation, shows greater reliability to identify and evaluate high Andean wetlands.
Methods for tree cover extraction from high resolution orthophotos and airborne LiDAR scanning in Spanish dehesas
Authors: Borlaf-Mena I. , Tanase M. A. , Gómez-Sal A.
Published: June 2019

Dehesas are high value agroecosystems that benefit from the effect tree cover has on pastures. Such effect occurs when tree cover is incomplete and homogeneous. Tree cover may be characterized from field data or through visual interpretation of remote sensing data, both time-consuming tasks. An alternative is the extraction of tree cover from aerial imagery using automated methods, on spectral derivate products (i.e. NDVI) or LiDAR point clouds. This study focuses on assessing and comparing methods for tree cover estimation from high resolution orthophotos and airborne laser scanning (ALS). RGB image processing based on thresholding of the ‘Excess Green minus Excess Red’ index with the Otsu method produced acceptable results (80%), lower than that obtained by thresholding the digital canopy model obtained from the ALS data (87%) or when combining RGB and LiDAR data (87.5%). The RGB information was found to be useful for tree delineation, although very vulnerable to confusion with the grass or shrubs. The ALS based extraction suffered for less confusion as it differentiated between trees and the remaining vegetation using the height. These results show that analysis of historical orthophotographs may be successfully used to evaluate the effects of management changes while LiDAR data may provide a substantial increase in the accuracy for the latter period. Combining RGB and Lidar data did not result in significant improvements over using LIDAR data alone.
Virtual reality in medicine: a brief overview and future research directions
Authors: Mazurek Justyna , Kiper Paweł , Cieślik Błażej , Rutkowski Sebastian , Mehlich Krzysztof , Turolla Andrea , Szczepańska-Gieracha Joanna
Published: June 2019

Virtual reality (VR), also called phantomatics, is an image of artificial reality created entirely in three-dimensional graphics with the use of information technology. VR makes it possible to experience the imaginary world as if it was real, where sensory data are delivered to the brain through a specialized system. The purpose of virtual medicine is to minimize direct contact and impact on human body during treatment. Taking into consideration the increasing accessibility of high quality electronic devices, their immense computing powers, and the continuously developing Internet infrastructure, the advancement in this area is only a matter of time. Therefore, the aim of the study was to identify the applications of VR in medicine, focusing on the areas of psychiatry and rehabilitation and considering guidelines for future research.
Assessment of the performance of novice futsal players in the execution of futsal-specific motor skills
Authors: Reis Marcos , Santos Jenisson , Matos Matheus , Cruz Thayron , Vasconcellos Fabricio , Almeida Marcos
Published: June 2019

Purpose

To compare the performance in the execution of specific motor skills among novice futsal players in 3 competitive categories (U-7, U-9, and U-11) and to compare their performance in specific motor skills during the offensive and defensive phases of the game.

Methods

Ten specific motor skills were investigated, including 6 offensive actions and 4 defensive actions, in 49 futsal players aged 6–11 years. Technical performance was analysed in terms of the number of actions, the effectiveness of the action (successful or unsuccessful), and where the action occurred (offensive or defensive midfield). One-way ANOVA was used
with the Tukey test, when appropriate, or Student’s t-test, with a significance level of 5%.

Results

Players in the older categories were more effective defensively than those in the younger categories (F2,46 = 6.04, p < 0.01, η2 = 0.21). The two older groups had an approximately two- and three-fold greater chance, respectively, of executing successful defensive technical actions (OR = 1.82, p < 0.05; OR = 2.83, p < 0.01). Furthermore, the players were more technically effective in the offensive phase of the game than in the defensive phase (M = 41.35, SD = 21.53 and M = 16.47, SD = 7.90, respectively; t96 = 7.60, p < 0.01, d = 1.69).

Conclusions

Players in older competitive categories were more effective, and players were more effective offensively than defensively.
Flexible approach for quantifying average long-term changes and seasonal cycles of tropospheric trace species
Authors: Parrish David D. , Derwent Richard G. , O'Doherty Simon , Simmonds Peter G.
Published: June 2019

Abstract. We present an approach for deriving a systematic
mathematical representation of the statistically significant features of the
average long-term changes and seasonal cycle of concentrations of trace
tropospheric species. The results for two illustrative data sets (time
series of baseline concentrations of ozone and N2O at Mace Head,
Ireland) indicate that a limited set of seven or eight parameter values
provides this mathematical representation for both example species. This
method utilizes a power series expansion to extract more information
regarding the long-term changes than can be provided by oft-employed linear
trend analyses. In contrast, the quantification of average seasonal cycles
utilizes a Fourier series analysis that provides less detailed seasonal
cycles than are sometimes represented as 12 monthly means; including
that many parameters in the seasonal cycle representation is not usually
statistically justified, and thereby adds unnecessary “noise” to the
representation and prevents a clear analysis of the statistical uncertainty
of the results. The approach presented here is intended to maximize the
statistically significant information extracted from analyses of time series
of concentrations of tropospheric species, regarding their mean long-term
changes and seasonal cycles, including nonlinear aspects of the long-term
trends. Additional implications, advantages and limitations of this approach
are discussed.
Application of open-path Fourier transform infrared spectroscopy (OP-FTIR) to measure greenhouse gas concentrations from agricultural fields
Authors: Lin Cheng-Hsien , Grant Richard H. , Heber Albert J. , Johnston Cliff T.
Published: June 2019

Abstract. Open-path Fourier transform infrared spectroscopy
(OP-FTIR) has often been used to measure hazardous or trace gases from hot
point sources (e.g. volcano, industrial, or agricultural facilities) but
seldom used to measure greenhouse gases (GHGs) from field-scale sources
(e.g. agricultural soils). Closed-path mid-IR laser-based N2O,
nondispersive-IR CO2 analysers, and OP-FTIR were used to measure
concentrations of N2O and CO2 at a maize cropping system during
9–19 June 2014. To measure N2O and CO2 concentrations accurately, we
developed a quantitative method of N2O∕CO2 analysis that minimized
interferences from diurnal changes of humidity and temperature. Two
chemometric multivariate models, classical least squares (CLS) and partial
least squares (PLS), were developed. This study evaluated various methods to
generate the single-beam background spectra and different spectral regions
for determining N2O and CO2 concentrations from OP-FTIR spectra. A
standard extractive method was used to measure the actual path-averaged
concentrations along an OP-FTIR optical path in situ, as a benchmark to
assess the feasibilities of these quantitative methods. Within an absolute
humidity range of 5000–20 000 ppmv and a temperature range of 10–35 ∘C, we found that the CLS model underestimated N2O
concentrations (bias =-4.9±3.1 %) calculated from OP-FTIR
spectra, and the PLS model improved the accuracy of calculated N2O
concentrations (bias =1.4±2.3 %). The bias of calculated
CO2 concentrations was -1.0±2.8 % using the CLS model. These
methods suggested that environmental variables potentially lead to biases in
N2O and CO2 estimations from OP-FTIR spectra and may help OP-FTIR
users avoid dependency on extractive methods of calibrations.
Evaluating biases in filter-based aerosol absorption measurements using photoacoustic spectroscopy
Authors: Davies Nicholas W. , Fox Cathryn , Szpek Kate , Cotterell Michael I. , Taylor Jonathan W. , Allan James D. , Williams Paul I. , Trembath Jamie , Haywood Jim M. , Langridge Justin M.
Published: June 2019

Abstract. Biases in absorption coefficients measured using a
filter-based absorption photometer (Tricolor Absorption Photometer, or TAP)
at wavelengths of 467, 528 and 652 nm are evaluated by comparing to
measurements made using photoacoustic spectroscopy (PAS). We report
comparisons for ambient sampling covering a range of aerosol types including
urban, fresh biomass burning and aged biomass burning. Data are also used to
evaluate the performance of three different TAP correction schemes. We found
that photoacoustic and filter-based measurements were well correlated, but
filter-based measurements generally overestimated absorption by up to 45 %. Biases varied with wavelength and depended on the correction scheme
applied. Optimal agreement to PAS data was achieved by processing the
filter-based measurements using the recently developed correction scheme of
Müller et al. (2014), which
consistently reduced biases to 0 %–18 % at all wavelengths. The biases
were found to be a function of the ratio of organic aerosol mass to
light-absorbing carbon mass, although applying the
Müller et al. (2014) correction
scheme to filter-based absorption measurements reduced the biases and the
strength of this correlation significantly. Filter-based absorption
measurement biases led to aerosol single-scattering albedos that were biased
low by values in the range 0.00–0.07 and absorption Ångström
exponents (AAEs) that were in error by ± (0.03–0.54). The discrepancy
between the filter-based and PAS absorption measurements is lower than
reported in some earlier studies and points to a strong dependence of
filter-based measurement accuracy on aerosol source type.
Late Quaternary climate variability at Mfabeni peatland, eastern South Africa
Authors: Miller Charlotte , Finch Jemma , Hill Trevor , Peterse Francien , Humphries Marc , Zabel Matthias , Schefuß Enno
Published: June 2019

Abstract. The scarcity of continuous, terrestrial, palaeoenvironmental records in
eastern South Africa leaves the evolution of late Quaternary climate and its
driving mechanisms uncertain. Here we use a ∼7 m long core
from Mfabeni peatland (KwaZulu-Natal, South Africa) to reconstruct climate
variability for the last 32 000 years (cal ka BP). We infer past
vegetation and hydrological variability using stable carbon
(δ13Cwax) and hydrogen isotopes (δDwax) of plant-wax
n-alkanes and use Paq to reconstruct water table changes. Our results
indicate that late Quaternary climate in eastern South Africa did not
respond directly to orbital forcing or to changes in sea-surface
temperatures (SSTs) in the western Indian Ocean. We attribute the arid
conditions evidenced at Mfabeni during the Last Glacial Maximum (LGM) to low
SSTs and an equatorward displacement of (i) the Southern Hemisphere
westerlies, (ii) the subtropical high-pressure cell, and (iii) the South Indian
Ocean Convergence Zone (SIOCZ), which we infer was linked to increased
Antarctic sea-ice extent. The northerly location of the high-pressure cell
and the SIOCZ inhibited moisture advection inland and pushed the
rain-bearing cloud band north of Mfabeni, respectively. The increased
humidity at Mfabeni between 19 and 14 cal kyr BP likely resulted from a
southward retreat of the westerlies, the high-pressure cell, and the SIOCZ,
consistent with a decrease in Antarctic sea-ice extent. Between 14 and 5 cal kyr BP, when the westerlies, the high-pressure cell, and the SIOCZ were in
their southernmost position, local insolation became the dominant control,
leading to stronger atmospheric convection and an enhanced tropical easterly
monsoon. Generally drier conditions persisted during the past ca. 5 cal ka BP,
probably resulting from an equatorward return of the westerlies, the
high-pressure cell, and the SIOCZ. Higher SSTs and heightened El Niño–Southern Oscillation (ENSO) activity
may have played a role in enhancing climatic variability during the past
ca. 5 cal ka BP. Our findings highlight the influence of the latitudinal
position of the westerlies, the high-pressure cell, and the SIOCZ in driving
climatological and environmental changes in eastern South Africa.
Influence of eccentricity of double eccentricity sleeves on the movements of swing head in rotary forging press
Authors: Liu Xin , Zhu Chun Dong , Jiang Xi , Zhang Yi
Published: June 2019

Abstract. Rotary forging is an innovative incremental metal forming
process, In a rotary forging press with double eccentricity sleeves, the
eccentricity of double eccentricity sleeves has significant effects on the
movements of swing head. The internal and external eccentricity of the
existing rotary forging machine is equal, except circular path, the rotation
speed of internal and external eccentric sleeves for the rose curve, spirals
curve and straight line is not equal, which will produce the oscillation
centrifugal force during the forming process and cause the violent shaking
on the machine. The shaking of the machine has an important influence on the
life of the equipment parts machining accuracy and surface profile of
parts, reducing the production efficiency. This paper proposes a method to
reduce shaking by changing eccentricity and studied the influence of
unequal eccentricity on the movements of swing head obtained the design
relationship of internal and external sleeves eccentricity, which can reduce
the shaking in rotary forging press. This study improving the working state
of the rotary forging machine and economic benefits.
Optimum Control of Grazing and Cattle Movement in the Silvopastoral Establishment "La Aguada" (Córdoba-Argentina)
Authors: Ventura Sergio Drumond , Delgado Angel Ramon Sanchez , Nascimento Vinicius Teixeira do , Plevich José Omar
Published: June 2019

Currently silvopastoral systems have been presented as a viable and sustainable alternative in economic, social and environmental terms. The objective of this work is to present an integer linear programming model (ILP), that numerically represents or simulates the optimal operating conditions of a silvopastoral system inspired by the typology of the rural establishment "La Aguada", an experimental agricultural and forestry center, belonging to the National University of Rio Cuarto and located in the province of Córdoba (Argentina). The model imposes conditions on the adequacy of the gain of the live weight of each animal of the herd considered in the system, as well as the optimal control of the areas of pasture and bovine movement. It is important to highlight that this is an attempt to mathematically model improvements in food production systems. Each ILP was solved using the INTLINPROG solver in MATLAB software. Thus, after the computational implementation, it was verified that the program meets all restrictions imposed, maximizes the gain of the live weight of each animal and optimizes the pasture area use, thus showing a consistent, balanced and recommended program for the economic controlling of a silvopastoral system in general.
Awareness and Perception of Senior Citizens on the Implementation of R.A. 9994 in San Isidro in Nueva Ecija in the Philippines
Authors: Cablao Jayson Y. , DG. Bonafe Camille Anne , Espinoza Christine Alaine B. , Cuya-Antonio Olive Chester , Casimiro Rosemarie R.
Published: June 2019

This study determined the awareness and perception of senior citizens on the implementation of R.A. 9994, or the Expanded Senior Citizen Act of 2010. It employed both qualitative and quantitative research design as it described the profile of the respondents, determined the level of awareness of the respondents on the benefits granted by RA 9994, and analyzed the extent of implementation of the benefits and privileges based on R.A. 9994. The respondents came from the three clustered barangays of San Isidro, Nueva Ecija in the Philippines. The researcher used a 5-point Likert Scale questionnaire. The data gathered revealed that Senior Citizens were “Moderately Aware” of most of the parameters presented such as the 20% discount, government assistance, and priority in express lanes. On the other hand, the mean response on the extent of implementation was verbally described as “Slightly Implemented.” The Analysis of Variance showed that the level of awareness of respondents across the clustered barangays does not vary significantly. Thus, from the findings, it is recommended that a thorough study with a greater number of respondents, including the relatives/primary care giver, should be involved. Firm and systematic assessment is also recommended to monitor the implementation of the programs.
Emersonian Moods, Peircean Sentiments, and Ellingtonian Tones
Authors: Colapietro Vincent
Published: June 2019

This article is an exploration of certain central features of the affective dimension of human lives. It moves from a consideration of moods, especially as these feature into several of Emerson's essays, to a consideration of sentiments, as they are treated by Peirce, and concludes with tones. At the center of this article, there is an attempt to bring into focus some of the most important connections among moods, sentiments, and tones. The ephemeral and variable character of moods is contrasted to the abiding and integrated character of sentiments in Peirce's sense. The article concludes with a discussion of tone in general and its bearing on democracy in particular. The topic of tone is first examined in light of James's “The Social Value of the College-Bred” and, then, in that of Duke Ellington's musical experiments in hitting upon the right sound, including the right tone. This is an ongoing experimental and improvisatory process in which “mistakes” are taken up and incorporated into the flow of the music or some other endeavor. “By their tone,” James insisted, “are all things human either lost or saved.” This text is dedicated to showing the contemporary relevance of James's claim.
Bigger than Football: Fan Anxiety and Memory in the Racial Present
Authors: Tarver Erin C.
Published: June 2019

Understanding many white football fans' responses to football players' protests against police brutality requires recognizing the historical and contemporary role of football fandom in managing racial and gendered anxieties. In this article, I analyze three distinct uses of memory by white football fans as they work through the anxiety that results when the sport fails to work in the way they expect. My analysis draws on the opposing views of football taken by the American philosophers Josiah Royce and George Santayana and on contemporary social science research on the behavior of sports fans. I show that contemporary fan hostility to protesting players is consistent with the social ills that have surrounded football since the era of Royce's critique.
Looking After the Future: Notes on Hope
Authors: Lysaker John T.
Published: June 2019

Hope is a complex social-psychological phenomenon. It combines cognitive and affective dimensions, and it is temporally extended, drawing upon the past in order to orient the present toward the future. In conversation with various texts, ranging from Ernst Bloch to Cornel West to Patrick Shade, the article offers a multidimensional account of hope, arguing that it is integral to human action and possibility.