bluuebunny/crossref_metadata_2025 huggingface dataset:
Buckling Tests for Laser-Welded Single Corrugated Core
Authors: Jokelainen Tero , Järvenpää Antti , Keskitalo Markku , Hietala Mikko , Mustakangas Aappo , Mäntyjärvi Kari
Published: November 2018

This study was employed to investigate the buckling effect for a single Vf corrugated core. Brief and simple designing method is developed for UHS sandwich structure. This method is based on simplified calculation of slenderness ratio integrated with FEM simulation. Method is developed for studying the local buckling resistance of sandwich structures to optimize the panel dimensions for maximal stiffness. Five different core dimensions were tested (angles of 110-135 ° and height of 35 - 55 mm). Buckling tests were made using two different steel grades; ultra-high-strength (UHS) ARS400 and DC01 mild steel. For comparison, FEM simulations were carried out for the ARS400. The results showed that even 600% higher bending resistance can be achieved for the panel structure using the ultra-high strength steel instead of the low strength counterpart. The comparison showed that the FEM-simulations can be used reliably estimating the buckling effects in UHS panel structures. The difference between the empirical and simulation results was 5.3% in average (S.D. 4.1). In practical tests, best angle and height for the ARS400 was 110 ° and 35 mm respectively. For the DC01, the best dimensions were 125 ° and 35 mm.
Bending Strength of Laser-Welded Sandwich Steel Panels of Ultra-High Strength Steel
Authors: Hietala Mikko , Järvenpää Antti , Keskitalo Markku , Mäntyjärvi Kari
Published: November 2018

The study was performed to investigate the bending resistance of laser-welded sandwich panels (Vf-core). The main aim of the study was to determine the effect of the tensile strength on bending strength of the panel structures. Panels were manufactured using an ultra-high strength (UHS) and low strength (LS) steels with yield strengths of 1200 and 200 MPa, respectively. Secondly, the bending strength of the panel structures was compared with the conventional sheet steels to estimate the possibilities for weight reduction. Results showed that the UHS steel panels had significantly higher bending strength than panels of the LS steel. The bending strength in the weakest loading direction of the UHS panel was approximately four times higher than the one of LS steel panel. The panels made with UHS steel faceplates and LS steel cores had better bending strength than LS steel panels. In comparison to UHS sheet steel, 30% weight saving is estimated by using the geometry optimized UHS steel panel.
Crack Width Estimation Using Feed and Cascade Forward Back Propagation Artificial Neural Networks
Authors: Shehata Hesham M. , Mohamed Yasser S. , Abdellatif Mohamed , Awad Taher H.
Published: November 2018

Automatic crack inspection techniques that limit the necessity of human have the potential to lower the cost and time of the process. In this study, a maximum crack width estimation approach is presented. Seventy nine segments of cracks are used for training the neural networks and twenty six segments are used for examination. The maximum width for each segment is measured using laser scanning microscope and segment image is captured and magnified using the microscope camera in order to obtain the extracted crack profile number of pixels. Feed and cascade forward back propagation artificial neural networks are designed and constructed. The input and output for the networks are the crack width in terms of number of pixels and the maximum estimated crack width respectively. It is shown that, the artificial neural networks technique can effectively be used to estimate the crack width. The feedforward back propagation structure which is designed with two layers and training function TRAINLM gives the best results in examination.
The Effect of Heating Rate on Texture and Formability of Ti-Nb Stabilized Ferritic Stainless Steel
Authors: Jaskari Matias , Järvenpää Antti , Karjalainen Pentti
Published: November 2018

Typical applications of ferritic stainless steels require good formability of the material that is highly dependent on the processing route. In this study, the effects of the heating rate and peak heating temperature on the texture and deep drawability (R-value) of a 78% cold rolled, stabilized 18Cr (AISI 441) ferritic stainless steel were studied. Pieces of cold rolled sheet were heated in a Gleeble 3800 simulator at the heating rates of 25 °C/s and 500 °C/s to various temperatures up to 1150 °C for 10 s holding before cooling at a rate of 35 °C/s. Microstructures were characterized and the texture of the annealed samples determined by the electron backscatter diffraction method. It was established that the high heating rate of 500 °C/s promotes the nucleation of grains with the near {111} orientations during the early state of the recrystallization. The maximum texture intensities were found at {554}<225>. The more effective nucleation of these grains resulted in a finer grain size and an increased intensity of the gamma-fibre texture which led to enhanced R-values. At high peak temperatures, the intense grain growth took place.
A Short Glance on Metal 3D AM
Authors: Iso-Junno Terho , Mäkelä Kimmo , Mäntyjärvi Kari , Jokelainen Tero
Published: November 2018

Metal 3D AM (Additive Manufacturing) has been becoming a more common production method for larger variety of parts. In this review the current situation and future development trends of the 3D metal AM are presented, concentrating on the SLM (Selective Laser Melting) technology. A holistic approach to the AM as a digital manufacturing method is presented and different manufacturing aspects of the AM production are identified. The most promising aspects for the future development are the automatization of the AM design tasks and automatization of the production. With the development of these aspects the production and cost efficiency of the metal AM can be increased to a more competitive level compared with other manufacturing methods.
In Implementing a Metal 3D AM Machine
Authors: Jokelainen Tero , Mäkelä Kimmo , Mustakangas Aappo , Mäkelä Jari , Mäntyjärvi Kari
Published: November 2018

Additive Manufacturing (AM) does not yet have a standardized way to measure performance. Here a AM machines dimensional accuracy is measured trough acceptance test (AT) and AM machines capability is tested trough test parts. Test parts are created with specific geometrical features using a 3D AM machine. Performance of the machine is then evaluated trough accuracy of test parts geometry. AM machine here uses selective laser melting (SLM) process. This machine has done Factory acceptance test (FAT) to ascertain this machine ́s geometrical accuracy with material AISI 316L. Manufacturer promises accuracy of ±0.05 mm. These parts are used as comparison to AT parts made in this study. After installation two AT parts are manufactured with AM machine. One with AISI 316L and one AlSi10Mg. Dimensional accuracy of geometrical features on these parts are then compared to FAT part and to one another. Machines capability is measured trough two test parts done with material AlSi10Mg. Two of the test parts are done at the same time using same model as the FAT. Parts are printed without supports and with features facing same directions. Features of these parts were then evaluated. Another test to find out AM machines capability was to create part consisting of pipes doing 90˚ angle resulting in horizontal and vertical holes. Dimensional accuracy and circularity of holes was measured. Through these tests machines capability is benchmarked.
Oxidation Characteristics of Porous Nickel Low-Chromium Binary Alloys in Air at 1273K for 100 h
Authors: Mohamed Lamiaa Z. , Ghanem Wafaa A. , El Kady Omayma A. , Lotfy Mohamed. M. , Ahmed Hafiz A. , Elrefaie Fawzi A.
Published: November 2018

The oxidation behavior of porous nickel low-chromium alloys containing up to 1 wt%Cr oxidized in air at 1273K for 100 h was investigated. Porous-duplex scale was formed on the 1 wt%Cr pellets while single oxide layers were obtained on the 0.25 and 0.5 wt%Cr pellets. Cavities were formed underneath the NiO scales and also between both layers formed on the oxidized 1 wt%Cr pellets. Accumulation of NiCr2O4 was noticed at the oxide/ metal interface. The growth mechanism of the scales was explained on the basis of molecular oxygen inward migration.
CH2O Adsorption on M (M = Li, Mg and Al) Atom Deposited ZnO Nano-Cage: DFT Study
Authors: Ammar Hussein Y.
Published: November 2018

The structural and electronic properties of Li, Mg and Al deposited ZnO nanocages and their effects on the adsorption of formaldehyde molecule have been investigated using the density functional theory (DFT) computations. To understand the behavior of the adsorbed CH2O molecule on the ZnO nanocage, results of DFT calculations of the M-deposited nanocages (M=Li, Mg and Al), as well as complex systems consisting of the adsorbed CH2O molecule on M-deposited ZnO nanocage were reported. The results presented include adsorption energies, bond lengths, electronic configurations, density of states and molecular orbitals. It was found that, the most energetically stable adsorption configurations of CH2O molecule on the bare ZnO leads to 12% dilation in C=O bond length of CH2O and 14% decrease in HOMO-LUMO gap of ZnO cluster. The most energetically stable adsorption configurations of CH2O molecule on Li, Mg and Al-deposited ZnO lead to 4%, 4% and 11% dilation in C=O bond length of CH2O and-0.66, -45 and , +66% change in HOMO-LUMO gap of ZnO nanocages, respectively. The interaction between CH2O with bare ZnO and M-deposited ZnO nanocages is attributed to charge transfer mechanism. These results may be meaningful for CH2O degradation and detection.
Two-Step Synthesis of Copper Sulfide-Graphene Counter Electrode for CdS Quantum Dot Sensitized Solar Cells
Authors: Hessein Amr , El-Moneim Ahmed Abd
Published: November 2018

The development of high performance and cost-effective counter electrode (CE) is a persistent objective in order to convey the quantum dot sensitized solar cell (QDSSC) from laboratories to markets benches. In the current study, we present a simple two-step approach for fabricating a highly efficient CE for QDSSC composes from copper sulfide (CuS) nanoparticles and reduced graphene oxide (RGO) mixture. The two-step approach gave us the opportunity to synthesis pure cupric sulfide (CuS) nanoparticles; in the first step and with smaller particle size before mixing with graphene. In the second step, different ratios from CuS and RGO were prepared and tested as counter electrodes in QDSSCs. The preliminary results obtained from CdS-QDSSCs employing CuS-RGO CE demonstrate that high dependency on the content of the CuS nanoparticles into the counter electrode. As high as 2.62% power conversion efficiency was exhibited by replacing 75% graphene content by CuS nanoparticles into the counter electrode. The obtained results were explained by means of electrochemical measurements of the fabricated CEs along with morphological and structural properties of the prepared nanocomposites.
Crystallographic Texture Investigation of Thick Section Friction Stir Welded AA6082 and AA5083 Using EBSD
Authors: Ahmed Mohamed Zaky , Wynne Bradley P. , Rainforth W. Mark , Martin Jonathan P.
Published: November 2018

In the present work, a FEI Sirion FEG-SEM equipped with a Nordlys CCD camera controlled by HKL Channel 5 software has been used to characterize the crystallographic texture of 20mm thick friction stir welded AA6082-T651 and AA5083-O. The crystallogaphic texture has been nvestigated near the top surface of the weld nugget at the shoulder affected region and near the base of the nugget in the probe affected region. The crystallographic texture in the shoulder affected region is complex in terms of determing the local reference frame of deformation and it requires complicated rotations to resemble the ideal simple shear texture. This implies the complex deformation histroy experinced in this region. However, the crystallographic texture in the probe-dominated region is simple shear texture. This implies that the deformation conditions across the whole weld nugget in this region are mianly dominated by the shear deformation generated by the probe rotation with the forward motion of the tool only playing a minor role in determining the local deformation gradient. Alternating bands between (+)and (C) was observed in the NG region of FSWed AA6082. The existence of A component is observed with an existence of strong C texture component which implies that when the C component is strong it can be associated with the A texture components.The crystallographic texture of AA5083 at both the shoulder and the probe dominated region is weak relative to that of the AA6082 .
Cyclic Behavior of Reversion-Treated Structures after Different Cold Rolling Reductions in an AISI 301LN Stainless Steel
Authors: Järvenpää Antti , Jaskari Matias , Karjalainen Pentti
Published: November 2018

Lower cold rolling reductions before reversion annealing for the grain size refinement are desired in industrial practice. This study demonstrates the effect of a low (32%) cold rolling reduction on cyclic behavior of a partially reversed (750 °C for 0.1s) structure in a 17Cr-7Ni-N type 301LN austenitic stainless steel and compares it with those of a 63% cold rolled and annealed and with a conventional coarse-grained structure. Stress amplitude and the amount of deformation-induced martensite formed under cyclic loading at the 0.6% total strain amplitude were recorded. The results showed that the partially reversed structure after the 32% cold rolling reduction exhibits the similar cyclic stress amplitude level and slight cyclic hardening as the 63% cold-rolled counterpart does. Even though the grain size refinement remains less effective at the lower reduction, the microstructure consists of higher fractions of strong retained cold-deformed austenite and martensite phases which increase the flow resistance. However, the coarse-grained structure exhibits a much lower initial stress amplitude and much more pronounced cyclic hardening. The susceptibility of austenite to transform deformation-induced martensite is practically similar among these three structures. However, the cyclic hardening is a caused by the formation of deformation-induced martensite, and the difference in the degree of cyclic hardening results from the big difference in the strength of the austenite between the partially reversed fine-grained and coarse-grained structures.
Developing High Strength-High Toughness Low Carbon Steel Using Combined V-Ti-Micro-Alloying and Different Thermo-Mechanical Treatments
Authors: Hamed Ahmed , Eissa Mamdouh , Kandil Abdelhakim , Ali Omnia , Mattar Taha
Published: November 2018

This work aims at designing and developing low carbon steel alloys to meet the high tensile strength, high ductility and high impact toughness properties. The effect of solid solution mechanism, precipitation hardening, as well as grain refinement were developed with different Manganese content (0.78-2.36wt%) combined with Vanadium(0.008-0.1wt%) and Titanium (0.002-0.072wt%) microalloying additions. The controlled thermo-mechanical treatments and chemical compositions play a big role in developing the microstructure and the corresponding mechanical properties. Therefore, the studied chemical compositions were treated thermo-mechanically by two different ways of changing start and finish forging temperatures with subsequent air cooling. The first way by start forging from 1050 to 830oC and the second from 950 to730oC. The second way of forging process developed finer grain sizes and higher ultimate tensile strengths for all the studied steel alloys. In spite of finer grain sizes, the impact toughness value was lower in the second regime due to detrimental influence of precipitation strengthening in the ferrite. A combination of 544 MPa yield strength, 615 MPa ultimate tensile strength, 20% elongation and 138 Joule impact toughness has been attained.
Manganese Distribution between Slag and Metal in the Egyptian Blast Furnace
Authors: Abd Elmomen Sanaa S.
Published: November 2018

Daily average slag and the corresponding hot metal samples were collected from blast furnace No.3 (1033m3 useful volume) of the Egyptian Iron and Steel Company (EISCO) charged with 100% self- fluxing sinter over a period of two months (from July to August 2015). The analyses of slag and metal were used to investigate the effects of temperature and basicity, defined as CaO/SiO2, on manganate capacity and manganese distribution between slag and metal.
Prominent Achievements of Laser Surface Treatment of Martensitic Stainless Steel and Alpha-Beta 6/4 Titanium Alloy
Authors: Hussein Abdelhamid , Al-Sayed Samar Reda , Hassab Elnaby Salah I. , Nofal Adel , Elgazzar Haytham
Published: November 2018

Conventional surface treatment processes are known to suffer from several limitations. Among them are energy consumption, complex heat treatment schedules and non-controllable heat affected zones. On the other side, when a high powered laser beam is used as a source of heat for surface treatment it will obviate most of these limitations. Laser surface engineering is one of these advanced surfacing technologies that receive growing interest to improve the surface properties of metals such as hardness, wear and corrosion resistance. Such treatments may be divided into two main categories: (i) those which only involve microstructural modification e.g. laser hardening and laser melting and (ii) other processes which lead to dual changes in microstructure and surface chemistry such as laser alloying and laser cladding. This paper comprises the experimental findings of two significant examples for laser surface engineering. The first study is concerned with surface hardening of AISI 416 martensitic stainless steel whereas the second study involves laser surface cladding of Ti-6Al-4V alloy. The outcome of the first work is a notable improvement of toughness at the same level of hardness and wear resistance as compared to the conventional hardening treatment. Additionally, the optimum condition for combined wear resistance, impact toughness and corrosion resistance was recorded at a laser heat input value of 21 J•mm-2. The second study is concerned with laser surface cladding of the titanium alloy with a powder blend composed of 60 wt% of WC and 40 wt% NiCrBSi alloy, by means of a high power Nd:YAG 2.2 kW laser. The best clad layers were obtained at a specific heat input of 60 J•mm-2. More than three-fold enhancement of the microhardness of the clad layers was achieved combined with a remarkable improvement of the alloy wear resistance.
A New Model of Projectile Motion for Resistance Proportional to Square of Velocity Components
Authors: Zhu Ping
Published: November 2018

A new model of the projectile motion for the resistance being proportional to the square of velocity components is investigated. In the course of the projectile motion, the direction of the resistance and the direction of the velocity are not entirely the opposite and on a straight line, in which the deviation angle exists. The size and the interrelation of velocity components determinate the size of the deviation angle, where deviation angles of some points take zeroes and another points take maximum values. The article makes deeply analysis for the new projectile model of velocity components, and gives interesting results.
Temperature Dependence of Commensurate Magnetic Resonance in Cuprate Superconductors
Authors: Lan Yu , Kuang Lü Lin
Published: November 2018

Within the kinetic energy driven superconducting mechanism, we have studied the temperature dependence of commensurate magnetic resonance in cuprate superconductors. It is shown that the commensurate magnetic resonance peak at the antiferromagnetic wave vector point persists in the superconducting state until the temperature rises to the superconducting transition temperature $T_{\rm c}$. The intensity of the resonance peak decreases with increasing temperature which is just like the temperature dependence of the superconducting gap parameter. Our results are in qualitative agreement with the inelastic neutron scattering experimental data and reflect that the commensurate magnetic resonance is closely related to the creation of the charge carrier pairs and thus the superconducting mechanism of cuprate superconductors.
Proposal and Demonstration of GaN-Based Normally-Off Vertical Field-Effect Transistor with a Design of Back Current Block Layer
Authors: Huang Huo Lin , Li F. , Sun Z. , Cao Y. , Zhang Z.
Published: November 2018

Vertical field-effect transistor (VFET) structure has the advantage in improving both the breakdown voltage (BV) and on-resistance (RON) of semiconductor power devices when compared with the lateral devices. GaN-based normally-off VFET device is designed and demonstrated in this work and an additional back current block layer (B-CBL) is proposed and employed to further improve the device performances. By introducing the B-CBL design, the electric field distribution along the gate aperture is more uniform which leads to an obvious increase (~30%) of BV in the proposed device while the RON is kept nearly constant. Therefore, the figure of merit (FOM) value of the proposed VFET is improved apparently in comparison with that of the conventional GaN-based VFET devices.
Extinction Capability of Carbon Nanofibers to Millimeter Wave
Authors: Wang Hong Xia , Hou Wei Jun , Wei Yi Wei , Liu Dai Zhi
Published: November 2018

Carbon nanofibers, whose diameter is between carbon nanotubes and conventional carbon fibers, is a new type of nanomaterials with features of good absorbing performance, small size and low density, and is easy to meet the requirements of passive interference materials.To study the interference properties of carbon nanofibers to millimeter wave, the interaction model of carbon nanofibers and electromagnetic field is established in this paper. The integral equation of the carbon nanofibers inductive current is established and solved by using of the method of moment, and the formula of mass extinction coefficient is obtained. The relationships between the mass extinction coefficient of carbon nanofibers and the millimeter wavelength, the diameter and length of fibers are analyzed via programming by Matlab. It is revealed that the extinction capability of carbon nanofibers decreases as the wavelength of millimeter wave increases. The larger the ratio of length to diameter of carbon nanofibers, the better its extinction capability to millimeter wave will be.
First-Principles Study of Electronic Structure, Optical Properties and LO-TO Splitting of GaP
Authors: Zhang Xian Bin , Wu Wen Jie , Deng Ning Kang , Wei Xu Yan , Wang Guan Qi
Published: November 2018

The electronic structure and optical properties of GaP were calculated using generalized gradients in density functional theory. The Bonn effective charge, optical frequency dielectric constant and the LO-TO splitting value were calculated by density functional theory perturbation method.
The Investigations of Electronic Structure in Armchair Graphene Nanoribbons Doped B at the Edge
Authors: Zhang Xian Bin , Deng Ning Kang , Wu Wen Jie , Wei Xu Yan , Wang Guan Qi
Published: November 2018

In this paper, the electronic structure in armchair graphene nanoribbons (AGNRs) and graphene nanoribbons doped B at the edge (B-AGNRs) are obtained based on the first principle theory. It shows that the band gap has the oscillation characteristic whose period is 3. The band gap oscillating characteristic gradually vanishes and tends to be stable after doping B at graphene nanoribbons edge. This provides a theoretical guidance for developing the stable graphene nanodevices.
Thermoelectric Method of Plastic Deformation Detection
Authors: Soldatov A.I. , Soldatov A.A. , Sorokin P.V. , Abouellail A.A. , Kostina M.A.
Published: November 2018

The paper presents an approach of non-destructive testing of plastic deformation of metals and alloys by measuring the differential thermoelectric power. Using the developed measuring device for this purpose, measurements of thermoelectric power were performed on several types of steels that are used in the manufacture of product pipelines. Incisions were made on the surface of the testes objects, for the purpose of experimental detection of the place of plastic deformation. In the process of stretching, thermoelectric power was measured at and near the place of the proposed plastic deformation. During the process of stretching the sample, the decrease in thermoelectric power measurement occurs almost linearly. The maximum change in the thermoelectric power measurement of the tested object was observe before the rapture discontinuity.
Model of Controlled Drug Release from the Polymer Implant
Authors: Komar L.A. , Svistkov A.L. , Kondyurin A.V.
Published: November 2018

A mathematical model for analysis of features of the drug release , previously introduced into a polymer implant, into a biological tissue is proposed. A carbon nanolayer obtained as a result of plasma-immersion ion implantation was created to improve biocompatibility with biological tissue on the surface of the implant. The medicine can go through micro-ruptures in this layer. Calculations show that the carbon layer allows a uniform release of the drug.
Temperature-dependent transport measurements with Arduino
Authors: Hilberer A. , Laurent G. , Lorin A. , Partier A. , Bobroff J. , Bouquet F. , Even C. , Fischbach J. M. , Marrache-Kikuchi Claire Akiko , Monteverde M. , Pilett B. , Quay Q.
Published: November 2018

The current performances of single-board microcontrollers render them attractive, not only for basic applications, but also for more elaborate projects, amongst which are physics teaching or research. In this article, we show how temperature-dependent transport measurements can be performed by using an Arduino board, from cryogenic temperatures up to room temperature or above. We focus on two of the main issues for this type of experiments: the determination of the sample temperature and the measurement of its resistance. We also detail two student-led experiments: evidencing the magnetocaloric effect in Gadolinium and measuring the resistive transition of a high critical temperature superconductor.
Received: 7 July 2018,  Accepted: 27 September 2018; Edited by: A. Marti,  M. Monteiro;  Reviewed by: R. Marotti, Instituto de Física, Facultad de Ingeniería - Universidad de la República, Uruguay; DOI: http://dx.doi.org/10.4279/PIP.100007
Cite as: A Hilberer, G Laurent, A Lorin, A Partier, J Bobroff, F Bouquet, C Even, J M Fischbach, C A Marrache Kikuchi, M Monteverde, B Pilette, Q Quay,  Papers in Physics 10, 100007(2018)
This paper, by A Hilberer, G Laurent, A Lorin, A Partier, J Bobroff, F Bouquet, C Even, J M Fischbach, C A Marrache Kikuchi, M Monteverde, B Pilette, Q Quay, is licensed under the Creative Commons Attribution License 4.0.
Geriatrics Curriculum Needs Assessment for Dermatology Residency Programs
Authors: Endo Justin , Awe Adam , Reddy Shalini T. , Hirshfield Laura E. , Kamin Carol , Lineberry Matthew
Published: November 2018

Background

Geriatric patients account for a growing proportion of dermatology clinic visits. Although their biopsychosocial needs differ from those of younger adults, there are no geriatrics training requirements for dermatology residency programs.

Objective

This study explored the state of geriatrics education in dermatology programs in 2016.

Methods

This constructivist study employed cross-sectional, mixed-methods analysis with triangulation of semistructured interviews, surveys, and commonly used curricular materials. We used purposive sampling of 5 US academic allopathic dermatology programs of different sizes, geographic locations, and institutional resources. Participants were interviewed about informal curricula, barriers, and suggestions for improving geriatrics education, and they also completed a survey about the geriatrics topics that should be taught. The constant comparative method with grounded theory was used for qualitative analysis. We identified formal geriatrics curricular content by electronically searching and counting relevant key texts.

Results

Fourteen of 17 participants (82%) agreed to be interviewed, and 10 of 14 (71%) responded to the survey. Themes of what should be taught included diagnosing and managing skin diseases common in older adults, holistic treatment, cosmetic dermatology, benign skin aging, and the basic science of aging. Topics currently covered that could be expanded included communication, systems-based challenges, ethical issues, safe prescribing, quality improvement, and elder abuse. Cosmetic dermatology was the most commonly taught formal geriatrics curricular topic.

Conclusions

There were discrepancies among topics participants felt were important to teach about geriatric dermatology and curricular coverage of these areas. We identified challenges for expanding geriatrics curricula and potential solutions.
Birch leaves and branches as a source of ice-nucleating macromolecules
Authors: Felgitsch Laura , Baloh Philipp , Burkart Julia , Mayr Maximilian , Momken Mohammad E. , Seifried Teresa M. , Winkler Philipp , Schmale III David G. , Grothe Hinrich
Published: November 2018

Abstract. Birch pollen are known to release ice-nucleating macromolecules (INM), but
little is known about the production and release of INM from other parts of
the tree. We examined the ice nucleation activity of samples from 10
different birch trees (Betula spp.). Samples were taken from nine
birch trees in Tyrol, Austria, and from one tree in a small urban park in
Vienna, Austria. Filtered aqueous extracts of 30 samples of leaves, primary
wood (new branch wood, green in colour, photosynthetically active), and
secondary wood (older branch wood, brown in colour, with no photosynthetic
activity) were analysed in terms of ice nucleation activity using VODCA
(Vienna Optical Droplet Crystallization Analyser), a cryo
microscope for emulsion samples. All samples contained ice-nucleating
particles in the submicron size range. Concentrations of ice nuclei ranged
from 6.7×104 to 6.1×109 mg−1 sample. Mean
freezing temperatures varied between −15.6 and −31.3 ∘C; the
range of temperatures where washes of birch pollen and dilutions thereof
typically freeze. The freezing behaviour of three concentrations of birch
pollen washing water (initial wash, 1 : 100, and 1 : 10 000) were
significantly associated with more than a quarter of our samples, including
some of the samples with highest and lowest activity. This indicates a
relationship between the INM of wood, leaves, and pollen. Extracts derived
from secondary wood showed the highest concentrations of INM and the highest
freezing temperatures. Extracts from the leaves exhibited the highest
variation in INM and freezing temperatures. Infrared spectra of the extracts
and tested birch samples show qualitative similarity, suggesting the chemical
components may be broadly similar.
Improvements to a long-term Rayleigh-scatter lidar temperature climatology by using an optimal estimation method
Authors: Jalali Ali , Sica Robert J. , Haefele Alexander
Published: November 2018

Abstract. Hauchecorne and Chanin (1980) developed a robust method to calculate middle-atmosphere
temperature profiles using measurements from Rayleigh-scatter lidars. This
traditional method has been successfully used to greatly improve our
understanding of middle-atmospheric dynamics, but the method has some
shortcomings regarding the calculation of systematic uncertainties and the
vertical resolution of the retrieval. Sica and Haefele (2015) have shown that the
optimal estimation method (OEM) addresses these shortcomings and allows
temperatures to be retrieved with confidence over a greater range of heights
than the traditional method. We have calculated a temperature climatology
from 519 nights of Purple Crow Lidar Rayleigh-scatter measurements using an
OEM. Our OEM retrieval is a first-principle retrieval in which the forward
model is the lidar equation and the measurements are the level-0 count
returns. It includes a quantitative determination of the top altitude of the
retrieved temperature profiles, the evaluation of nine systematic plus random
uncertainties, and the vertical resolution of the retrieval on a
profile-by-profile basis. Our OEM retrieval allows for the vertical
resolution to vary with height, extending the retrieval in altitude 5 to
10 km higher than the traditional method. It also allows the comparison of
the traditional method's sensitivity to two in-principle equivalent methods
of specifying the seed pressure: using a model pressure seed versus using a
model temperature combined with the lidar's density measurement to calculate
the seed pressure. We found that the seed pressure method is superior to
using a model temperature combined with the lidar-derived density. The
increased altitude capability of our OEM retrievals allows for a comparison
of the Rayleigh-scatter lidar temperatures throughout the entire altitude
range of the sodium lidar temperature measurements. Our OEM-derived Rayleigh
temperatures are shown to have improved agreement relative to our previous
comparisons using the traditional method, and the agreement of the
OEM-derived temperatures is the same as the agreement between existing sodium
lidar temperature climatologies. This detailed study of the calculation of
the new Purple Crow Lidar temperature climatology using the OEM establishes
that it is both highly advantageous and practical to reprocess existing
Rayleigh-scatter lidar measurements that cover long time periods, during
which time the lidar may have undergone several significant equipment
upgrades, while gaining an upper limit to useful temperature retrievals
equivalent to an order of magnitude increase in power-aperture product due to
the use of an OEM.
Geomagnetic Conjugate Observations of Ionospheric Disturbances in response to North Korea Underground Nuclear Explosion on 3 September 2017
Authors: Liu Yi , Zhou Chen , Tang Qiong , Chen Guanyi , Zhao Zhengyu
Published: November 2018

Abstract. We report observations of ionospheric disturbances in response to North Korea underground nuclear explosion (UNE) on 3 September 2017. By using data from IGS (International GNSS Service) stations and Swarm satellite, geomagnetic conjugate ionospheric disturbances were observed. The observational evidences showed that UNE-generated ionospheric disturbances propagated radially from the UNE epicenter with the velocity of ~280m/s. We propose that the ionospheric disturbances are results of electrodynamic process caused by LAIC (Lithosphere-Atmosphere-Ionosphere Coupling) electric field penetration. LAIC electric field can also be mapped to the conjugate hemispheres along the magnetic field line and consequently cause ionospheric disturbances in conjugate regions. The UNE-generated LAIC electric field penetration plays an important role in the ionospheric disturbances in the region of the nuclear test site nearby and the corresponding geomagnetic conjugate points.
Spatiotemporal transformation of dissolved organic matter along an alpine stream flow path on the Qinghai–Tibet Plateau: importance of source and permafrost degradation
Authors: Wang Yinghui , Spencer Robert G. M. , Podgorski David C. , Kellerman Anne M. , Rashid Harunur , Zito Phoebe , Xiao Wenjie , Wei Dandan , Yang Yuanhe , Xu Yunping
Published: November 2018

Abstract. The Qinghai–Tibet Plateau (QTP) accounts for approximately
70 % of global alpine permafrost and is an area sensitive to climate
change. The thawing and mobilization of ice-rich and organic-carbon-rich
permafrost impact hydrologic conditions and biogeochemical processes on the
QTP. Despite numerous studies of Arctic permafrost, there are no reports to
date for the molecular-level in-stream processing of permafrost-derived
dissolved organic matter (DOM) on the QTP. In this study, we examine temporal
and spatial changes of DOM along an alpine stream (3850–3207 m above sea
level) by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR
MS), accelerator mass spectrometry (AMS) and UV–visible spectroscopy.
Compared to downstream sites, dissolved organic matter (DOM) at the
headstream site exhibited older radiocarbon age, higher mean molecular
weight, higher aromaticity and fewer highly unsaturated compounds. At the
molecular level, 6409 and 1345 formulas were identified as unique to the
active layer (AL) leachate and permafrost layer (PL) leachate, respectively.
Comparing permafrost leachates to the downstream site, 59 % of
AL-specific formulas and 90 % of PL-specific formulas were degraded,
likely a result of rapid in-stream degradation of permafrost-derived DOM. From
peak discharge in the summer to low flow in late autumn, the DOC
concentration at the headstream site decreased from 13.9 to
10.2 mg L−1, while the 14C age
increased from 745 to 1560 years before present (BP), reflecting an increase
in the relative contribution of deep permafrost carbon due to the effect of
changing hydrological conditions over the course of the summer on the DOM source
(AL vs. PL). Our study thus demonstrates that hydrological conditions impact
the mobilization of permafrost carbon in an alpine fluvial network, the
signature of which is quickly lost through in-stream mineralization and
transformation.
Technical note: Problem-specific variators in a genetic algorithm for the optimization of drinking water networks
Authors: van Laarhoven Karel , Vertommen Ina , van Thienen Peter
Published: November 2018

Abstract. Genetic algorithms can be a powerful tool for the automated design
of optimal drinking water distribution networks. Fast convergence of such
algorithms is a crucial factor for successful practical implementation at
the drinking water utility level. In this technical note, we therefore
investigate the performance of a suite of genetic variators that was
tailored to the optimization of a least-cost network design. Different
combinations of the variators are tested in terms of convergence rate and
the robustness of the results during optimization of the real-world drinking
water distribution network of Sittard, the Netherlands. The variator
configurations that reproducibly reach the furthest convergence after
105 function evaluations are reported. In the future these may aid in
dealing with the computational challenges of optimizing real-world networks.
Bias correction of simulated historical daily streamflow at ungauged locations by using independently estimated flow duration curves
Authors: Farmer William H. , Over Thomas M. , Kiang Julie E.
Published: November 2018

Abstract. In many simulations of historical daily streamflow distributional bias
arising from the distributional properties of residuals has been noted. This
bias often presents itself as an underestimation of high streamflow and an
overestimation of low streamflow. Here, 1168 streamgages across the
conterminous USA, having at least 14 complete water years of daily
data between 1 October 1980 and 30 September 2013, are used to explore a
method for rescaling simulated streamflow to correct the distributional bias.
Based on an existing approach that separates the simulated streamflow into
components of temporal structure and magnitude, the temporal structure is
converted to simulated nonexceedance probabilities and the magnitudes are
rescaled using an independently estimated flow duration curve (FDC) derived
from regional regression. In this study, this method is applied to a pooled
ordinary kriging simulation of daily streamflow coupled with FDCs estimated
by regional regression on basin characteristics. The improvement in the
representation of high and low streamflows is correlated with the accuracy
and unbiasedness of the estimated FDC. The method is verified by using an
idealized case; however, with the introduction of regionally regressed FDCs
developed for this study, the method is only useful overall for the upper
tails, which are more accurately and unbiasedly estimated than the lower
tails. It remains for future work to determine how accurate the estimated
FDCs need to be to be useful for bias correction without unduly reducing
accuracy. In addition to its potential efficacy for distributional bias
correction, this particular instance of the methodology also represents a
generalization of nonlinear spatial interpolation of daily streamflow using
FDCs. Rather than relying on single index stations, as is commonly done to
reflect streamflow timing, this approach to simulation leverages
geostatistical tools to allow a region of neighbors to reflect streamflow timing.
Modes of writing in a digital age: The good, the bad and the unknown
Authors: Mangen Anne
Published: November 2018

With digitization, our modes of writing change and we go from writing by putting pen to paper, to typing on a variety of screens. In educational as well as in leisurely settings, writing by hand is increasingly marginalized, and may in a foreseeable future be abandoned altogether. Summarizing some of the research comparing handwriting and typewriting, this article aims to shed light on some salient features handwriting and keyboard writing, and to discuss what may be the implications of the ongoing marginalizing or even abandonment of handwriting — in a short- and long-term perspective.
Bibliotherapy in the age of digitization
Authors: Kuijpers Moniek M.
Published: November 2018

This contribution reviews both theoretical and empirical research on the effects of absorbed reading and bibliotherapy on subjective psychological well-being, paying special attention to the possible influence of digitization on this relationship. Reading on tablets, for example, could prove counter-productive for obtaining a state of absorption and thus modern-day tablet-readers may miss out on potential health benefits that absorbed reading of literature might provide. On the other hand, the connection that tablets provide to online reader communities and thus online bibliotherapeutic resources, might prove even more beneficial than obtaining a state of absorption during reading.
Scholars’ temporal participation on, temporary disengagement from, and return to Twitter
Authors: Veletsianos George , Kimmons Royce , Belikov Olga , Johnson Nicole
Published: November 2018

Even though the extant literature investigates how and why academics use social media, much less is known about academics’ temporal patterns of social media use. This mixed methods study provides a first-of-its-kind investigation into temporal social media use. In particular, we study how academics’ use of Twitter varies over time and examine the reasons why academics temporarily disengage and return to the social media platform. We employ data mining methods to identify a sample of academics on Twitter (n = 3,996) and retrieve the tweets they posted (n = 9,025,127). We analyze quantitative data using descriptive and inferential statistics, and qualitative data using the constant comparative approach. Results show that Twitter use is predominantly connected to traditional work hours and is well-integrated into academics’ professional endeavors, suggesting that professional use of Twitter has become “ordinary.” Though scholars rarely announce their departure from or return to Twitter, approximately half of this study’s participants took some kind of a break from Twitter. Although users returned to Twitter for both professional and personal reasons, conferences and workshops were found to be significant events stimulating the return of academic users.
Testing Google Scholar bibliographic data: Estimating error rates for Google Scholar citation parsing
Authors: Zeitlyn David , Beardmore-Herd Megan
Published: November 2018

We present some systematic tests of the quality of bibliographic data exports available from Google Scholar. While data quality is good for journal articles and conference proceedings, books and edited collections are often wrongly described or have incomplete data. We identify a particular problem with material from online repositories.
The Challenges of Creating Sustainable Competitive Advantage in the Banking Industry in Iraq
Authors: Alalie Helal Mouneer , Harada Yoshifumi , Noor Idris Md
Published: November 2018

Sustainable Competitive Advantage plays a key role in evaluating the strategic performance of an organization. The purpose of this study is to contribute to the understanding of how Sustainable Competitive Advantage is developed and applied in evaluating the performance of a large local bank in Iraq. Due to lack of research work in this area of banking sector in Iraq, this study shall contribute to the knowledge on how banks in Iraq may apply the Sustainable Competitive Advantage and how they might turn strategic vision into potential performance. The use of the Sustainable Competitive Advantage developed here is limited to the very bank studied here; however, the approach could trigger off reflections among policy makers and other banks to start using the Sustainable Competitive Advantage. The customers tend to deal with the banks that are able to develop their banking services in distinctive way as well as wishing to respond quickly to the wishes of customers, especially if we know how much similarity there is between those services. Thus, the need is urgent for excellence as well as for achieving a competitive advantage compared to other banks. Yet, that cannot be done on the long term unless the bank has the ability to adapt to environmental variables in general and to customers desires in particular. This requires adopting a comprehensive strategy for the purpose of accommodating and amending the procedures for the provision of the service. Lately, plenty of banks are being brazen-out due to confronting considerable rivalry. This is mostly due to these banks failing to have the power of proposing for attractive offers or even having acceptable ties with customers of theirs. This paper aims at analyzing means that can help a bank securing an agile rivalry in a market that is always about competition and winning customers and business accordingly. According to what the discussion has brought up, the idea of sustainability is growing faster lately as a vital criterion marking the size of corporations react for challenges that bear a strategic core nature. According to the conclusion of the paper, there is a necessity for a bank to have the capability of overcoming the inertia of change as well as intersecting new opportunities of the relevant market.
Preferência alimentar de Dasypus novemcinctus (Linnaeus, 1758) ex-situ
Authors: Testa Carolyne Assis Eigenheer Pinke , Castro Thiago Ferla Novais , Rosa Patrícia Sammarco , Sartori Maria Márcia Pereira , Hippólito Alícia Giolo , Melchert Alessandra
Published: November 2018

A adaptação de tatus às dietas utilizadas em cativeiro costuma ser de difícil realização, assim é recomendado oferecer vários alimentos diferentes para auxiliar na aceitação. No entanto, não há relatos da preferência alimentar desta espécie sob cuidados humanos. Assim, este trabalho objetivou avaliar a preferência alimentar de tatus (Dasypus novemcintus) mantidos em cativeiro, expostos a quatro dietas diferentes, variando a origem e a quantidade de proteína. Para tal, o experimento foi realizado durante cinco semanas, sendo que as quatro primeiras semanas foi um período de manejo preliminar e a quinta semana foi realizada a coleta dos dados. A preferência alimentar, segundo a frequência de consumo, foi pela dieta com maior porcentagem de proteína de origem animal (dieta 2). Já segundo a ingestão alimentar, a preferência foi pelas dietas com maior porcentagem de proteína total (dietas 1 e 2). Em conclusão, a preferência alimentar de tatus ex-situ parece estar relacionada à maior inclusão de proteína, principalmente quando esta é de origem animal.