bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation and Modeling of Rigid Aircraft Aerodynamic Responses to Arbitrary Gust Distributions
Authors: Ghoreyshi Mehdi , Greisz Ivan , Jirasek Adam , Satchell Matthew
Published: April 2018

The stresses resulting from wind gusts can exceed the limit value and may cause large-scale structural deformation or even failure. All certified airplanes should therefore withstand the increased loads from gusts of considerable intensity. A large factor of safety will make the structure heavy and less economical. Thus, the need for accurate prediction of aerodynamic gust responses is motivated by both safety and economic concerns. This article presents the efforts to simulate and model air vehicle aerodynamic responses to various gust profiles. The computational methods developed and the research outcome will play an important role in the airplane’s structural design and certification. Cobalt is used as the flow solver to simulate aerodynamic responses to wind gusts. The code has a user-defined boundary condition capability that was tested for the first time in the present study to model any gust profile (intensity, direction, and duration) on any arbitrary configuration. Gust profiles considered include sharp edge, one minus cosine, a ramp, and a 1-cosine using tabulated data consisting of gust intensity values at discrete time instants. Test cases considered are a flat plate, a two-dimensional NACA0012 airfoil, and the high Reynolds number aero-structural dynamics (HIRENASD) configuration, which resembles a typical large passenger transport aircraft. Test cases are assumed to be rigid, and only longitudinal gust profiles are considered, though the developed codes can model any gust angle. Time-accurate simulation results show the aerodynamic responses to different gust profiles including transient solutions. Simulation results show that sharp edge responses of the flat plate agree well with the Küssner approximate function, but trends of other test cases do not match because of the thin airfoil assumptions made to derive the analytical function. Reduced order aerodynamic models are then created from the convolution integral of gust amplitude and the time-accurate responses to sharp-edge gusts. Convolution models are next used to predict aerodynamic responses to arbitrary gust profiles without the need of running time-accurate simulations for every gust shape. The results show very good agreement between developed models and simulation data.
A Comparative Study of Gold Impregnation Methods for Obtaining Metal/Semiconductor Nanophotocatalysts: Direct Turkevich, Inverse Turkevich, and Progressive Heating Methods
Authors: Matamoros-Ambrocio Mayra , Ruiz-Peralta María de Lourdes , Chigo-Anota Ernesto , García-Serrano Jesús , Pérez-Centeno Armando , Sánchez-Cantú Manuel , Rubio-Rosas Efraín , Escobedo-Morales Alejandro
Published: April 2018

ZnO nanostructures decorated with gold nanoparticles (Au-NPs) were synthesized by thermal decomposition of ZnO2 powders and their subsequent impregnation of metal nanoparticles using either the Direct Turkevich Method, the Inverse Turkevich Method, or the Progressive Heating Method. It was found that the impregnation approach influences the resulting microstructure and photocatalytic activity of the obtained materials. While the Direct Turkevich approach gave the highest yield of metal loading, the smallest Au-NPs were obtained by Inverse Turkevich and the Progressive Heating Method. The photocatalytic activity of the pristine support and gold-loaded samples was studied in the decolorization of Rhodamine B solutions using UV- and pure visible-light illumination. All Au-NPs/ZnO samples showed higher photocatalytic activity than the bare support when UV-light was used. This effect is attributed to a charge carrier separation due to electron transfer from ZnO to the metal nanoparticles and the built-in electric field at the interfaces. Contrarily to most reports, visible-light sensitization using plasmonic nanoparticles was not observed. The experimental evidence points against hot-electron injection from Au-NPs to the semiconductor component. This behavior is associated with the height of the Schottky barrier at the metal-semiconductor junctions. The differences in the photocatalytic performance among the samples under UV- and visible-light are explained in terms of the characteristics of the Au-NPs driven by the growth mechanism involved in each impregnation method and the physicochemical properties of the generated interfaces.
Escherichia coli Colonization in Neonates: Prevalence, Perinatal Transmission, Antimicrobial Susceptibility, and Risk Factors
Authors: Tamelienė Rasa , Barčaitė Eglė , Stonienė Dalia , Buinauskienė Jūratė , Markūnienė Eglė , Kudrevičienė Aušrelė , Vitkauskienė Astra , Jomantienė Daiva , Nadišauskienė Rūta
Published: April 2018

Escherichia coli is one of the leading causes of early-onset neonatal sepsis in many industrialized countries. However, there is a lack of studies on Escherichia coli colonization in women and neonates. The study aimed at determining the prevalence Escherichia coli among pregnant women and newborns, perinatal transmission, antimicrobial susceptibility, and risk factors for neonatal colonization. Material and Methods. In this prospective, cross-sectional study, 827 infants born to 808 mothers were enrolled. The study was carried out from October 1, 2006, to June 30, 2007. Women were screened for E. coli carriage at 35–37 weeks of gestation or on admission for premature rupture of membranes and delivery; neonates, within 15 minutes of their lives. Risk factors for colonization were collected by a questionnaire and were recorded during labor. Results. Maternal E. coli colonization rate was 19.9%; neonatal, 14.4%; and transmission rate, 21.4%. Less than one-fourth (22.7%) of neonatal E. coli strains were resistant to ampicillin. Logistic regression analysis revealed that anal sexual intercourse (OR, 3.91; 95% CI, 1.87–8.19), one sexual partner (OR, 2.01; 95% CI, 1.30–3.11), maternal vaginal Escherichia coli colonization (OR, 1.81; 95% CI, 1.12–2.93), maternal body mass index of ≤27 (OR, 1.77; 95% CI, 1.15–2.73), and maternal education lower than university level (OR, 1.70; 95% CI, 1.06–2.74) were associated with neonatal Escherichia coli colonization. Conclusions. The prevalence of maternal Escherichia coli colonization was higher in this study than other studies (19.9%). Neonatal Escherichia coli colonization was 14.4%. The resistance of Escherichia coli isolates to ampicillin was not high (22.7%). Improvement of maternal education and modification of mothers’ sexual habits need to be undertaken to prevent neonatal Escherichia coli colonization.
Quality of Life in Patients With Age-Related Macular Degeneration
Authors: Šiaudvytytė Lina , Mitkutė Dovilė , Balčiūnienė Jūratė
Published: April 2018

The aim of this study was to evaluate the quality of life in persons affected by agerelated macular degeneration. Material and Methods. The study was performed in the Clinic of Ophthalmology, Hospital of Lithuanian University of Health Sciences. A total of 140 patients completed the Visual Functioning Questionnaire and the Hospital Anxiety and Depression Scale (HADS) during this prospective study. The patients were divided into two groups: patients with age-related macular degeneration (70 patients) and control patients (70 patients). Results. There was a significant difference in the quality of life between groups (P<0.0001). Analyzing patients with age-related macular degeneration within the group (patients with monocular or binocular disorders), significant differences in near vision (P=0.003), far vision (P=0.04), color vision (P=0.01), and social functioning (P=0.02) were observed. Mental health (r=0.326, P=0.02), dependency (r=0.340, P=0.02), and role difficulties (r=0.355, P=0.01) were found to be significantly associated with general vision in the age-related macular degeneration group. Conclusions. Age-related macular degeneration appeared to have a great impact on the quality of life. General vision impairment caused by age-related macular degeneration affects patient’s mental health, dependency, and role difficulties.
Whole Genome Classification and Phylogenetic Analyses of Rotavirus B strains from the United States
Authors: Shepherd Frances , Herrera-Ibata Diana , Porter Elizabeth , Homwong Nitipong , Hesse Richard , Bai Jianfa , Marthaler Douglas
Published: April 2018

Rotaviruses (RVs) are a major etiological agent of acute viral gastroenteritis in humans and young animals, with rotavirus B (RVB) often detected in suckling and weaned pigs. Group A rotavirus classification is currently based on the two outer capsid proteins, VP7 and VP4, and the middle layer protein, VP6. Using RVB strains generated in this study and reference sequences from GenBank, pairwise identity frequency graphs and phylogenetic trees were constructed for the eleven gene segments of RVB to estimate the nucleotide identity cutoff values for different genotypes and determine the genotype diversity per gene segment. Phylogenetic analysis of VP7, VP4, VP6, VP1–VP3, and NSP1–NSP5 identified 26G, 5P, 13I, 5R, 5C, 5M, 8A, 10N, 6T, 4E, and 7H genotypes, respectively. The analysis supports the previously proposed cutoff values for the VP7, VP6, NSP1, and NSP3 gene segments (80%, 81%, 76% and 78%, respectively) and suggests new cutoff values for the VP4, VP1, VP2, VP3, NSP2, NSP4, and NSP5 (80%, 78%, 79%, 77% 83%, 76%, and 79%, respectively). Reassortment events were detected between the porcine RVB strains from our study. This research describes the genome constellations for the complete genome of Group B rotaviruses in different host species.
Proposed Analytic Framework for Student Relationship Management based on a Systematic Review of CRM Systems Literature
Authors: Gholami Hamed , Zameri Mat Saman Muhamad , Mardani Abbas , Streimikiene Dalia , Sharif Safian , Zakuan Norhayati
Published: April 2018

Notwithstanding the research attention given to the importance and capability of the student relationship management strategy in higher education sustainability, there is no any systematic framework for implementation. This research as one of the preliminary studies has been undertaken to provide a structural framework of strategic practices for positioning this strategy at an operational level. In doing so, a methodological approach was implemented in two tiers. Firstly, a systematic review of the leading-edge literature on the customer relationship management systems was performed owing to the lack of significant research on the topic, as well as the structure and nature of the concept. Then, the principal components factor analysis with varimax rotation, which is a method of exploratory factor analysis was used to finalize the research. The findings revealed an articulated structural framework with five hypotheses, which may partially or fully be applied to narrow the major gap in the current knowledge. The measurement scale has also been developed for simplification in implementation of the application. Limitations and directions for future research were accordingly discussed.
The Spatial Analysis of Regional Innovation Performance and Industry-University-Research Institution Collaborative Innovation—An Empirical Study of Chinese Provincial Data
Authors: Wang Xu , Fang Hong , Zhang Fang , Fang Siran
Published: April 2018

Previous studies have pointed out that Industry-University-Research Institution (IUR) collaborative innovation is an important means to ensure the sustainable development of regional innovation, and there may be spillover effects among different regional innovation systems. However, the impact of regional spatial correlation and IUR collaborative innovation synergy degree on regional innovation performance is not that clear. Based on the panel data of 31 regions in China from 2006 to 2015, we construct static and dynamic spatial econometrics models to analysis the relationships among regional innovation performance, IUR collaborative innovation and spatial correlation. The research results show that there are significant positive spillover effects among different regions, indicating that the dynamic flows of innovation elements among regions is conducive to improve the regional innovation performance. In addition, IUR collaboration innovation also has a positive impact on regional innovation performance: the current period of IUR synergy degree has a negative impact, while the lagged one has a positive impact. It means that it will take a while for IUR collaborative innovation to be effective and it will have far-reaching contributions to long-term improvements rather than short-term benefits in social development. The results are significant for both static and dynamic spatial econometrics models. The conclusions of this paper have important policy significance to fully understand the coordination of innovative elements and promote the sustainable development of regional innovation systems.
Post-traumatic Stress Disorder and Social Isolation among North Korean Refugee Women in South Korea: The Moderating Role of Formal and Informal Support
Authors: Ryu Wonjung , Park Sun Won
Published: April 2018

While there is abundant literature on the positive correlation between refugee post-traumatic stress disorder (PTSD) and social isolation, few studies have examined the moderating effects of formal and informal interpersonal support. This study on 154 refugee women from North Korea examines the moderating effects of formal and informal interpersonal support on the relationship between PTSD and social isolation. Data from the 2012 survey of the Ministry of Gender Equality and Family in South Korea Study on Support for Independent Living Tailored to North Korean Refugee Women Exposed to Violence were included in the present study. The study results confirmed the positive correlation between PTSD and social isolation and verified the protective effects of formal support. These findings will contribute to policy changes and early proactive interventions to reduce the social isolation of North Korean refugee women in South Korea.
OSCILLATORY BEHAVIOR OF SECOND ORDER NONLINEAR DIFFERENTIAL EQUATIONS WITH A SUBLINEAR NEUTRAL TERM
Authors: Grace Said R. , Graef John R.
Published: April 2018

The authors establish some new criteria for the oscillation of solutions of second order nonlinear diﬀerential equations with a sublinear neutral term by reducing the equation to a linear one. Their results are illustrated with an example.
PARALLEL SOLUTION METHODS AND PRECONDITIONERS FOR EVOLUTION EQUATIONS
Authors: Axelsson Owe , Neytcheva Maya , Liang Zhao-Zheng
Published: April 2018

The recent development of the high performance computer platforms shows a clear trend towards heterogeneity and hierarchy. In order to utilize the computational power, particular attention must be paid to ﬁnding new algorithms or adjust existing ones so that they better match the HPC computer architecture. In this work we consider an alternative to classical time-stepping methods based on use of time-harmonic properties and discuss solution approaches that allow eﬃcient utilization of modern HPC resources. The method in focus is based on a truncated Fourier expansion of the solution of an evolutionary problem. The analysis is done for linear equations and it is remarked on the possibility to use two- or multilevel mesh methods for nonlinear problems, which can enable further, even higher degree of parallelization. The arising block matrix system to be solved admits a two-by-two block form with square blocks, for which a very eﬃcient preconditioner exists. It leads to tight eigenvalue bounds for the preconditioned matrix and, hence, to a very fast convergence of a preconditioned Krylov subspace or iterative reﬁnement method. The analytical background is shown as well as some illustrating numerical examples.
CALCULATING DISPERSION RELATIONS FOR WAVEGUIDE IMMERSED IN PERFECT FLUID
Authors: Nečiūnas Audrius , Patašius Martynas , Barauskas Rimantas
Published: April 2018

Conventional ﬁnite element method (FEM) is capable of obtaining wave solutions, but large discretized structures at high frequency require high computational resources, the computational domain can be reduced by combining FEM with analytical assumption for guided wave. Semi Analytical Finite Element (SAFE) formulation for immersed waveguide in perfect ﬂuid is used for acquiring propagating wave modes as dynamic equilibrium states. Modes are solutions to eigenvalue problem and provide with important characteristic features of the guided waves – phase velocity, attenuation, wave structure, etc. The eﬀect of surrounding leaky medium is modeled via traction boundary condition, which is based on assumption of the continuity of stresses at solid-ﬂuid interface. The boundary condition causes wave attenuation due to energy leakage into outer medium. The derivation of the eigen-problem takes into account complex wavenumbers of leaky wave in ﬂuid and guided wave in a three-dimensional waveguide. Linearization procedure for solving nonlinear eigenvalue problem is used. Dispersion relations for immersed waveguide with Rayleigh damping are obtained. The limits of applications of Rayleigh damping and convergence analysis of immersed waveguide model are discussed.
Evidence for a Sub-Chandrasekhar-mass Type Ia Supernova in the Ursa Minor Dwarf Galaxy
Authors: McWilliam Andrew , Piro Anthony L. , Badenes Carles , Bravo Eduardo
Published: April 2018

A long-standing problem is identifying the elusive progenitors of Type Ia supernovae (SNe Ia), which can roughly be split into Chandraksekhar and sub-Chandrasekhar-mass events. An important difference between these two cases is the nucleosynthetic yield, which is altered by the increased neutron excess in Chandrasekhar progenitors due to their pre-explosion simmering and high central density. Based on these arguments, we show that the chemical composition of the most metal-rich star in the Ursa Minor dwarf galaxy, COS 171, is dominated by nucleosynthesis from a low-metallicity, low-mass, sub-Chandrasekhar-mass SN Ia. Key diagnostic abundance ratios include Mn/Fe and Ni/Fe, which could not have been produced by a Chandrasekhar-mass SN Ia. Large deficiencies of Ni/Fe, Cu/Fe and Zn/Fe also suggest the absence of alpha-rich freeze-out nucleosynthesis, favoring low-mass white dwarf progenitors of SNe Ia, near 0.95 M
⊙, from comparisons to numerical detonation models. We also compare Mn/Fe and Ni/Fe ratios to the recent yields predicted by Shen et al., finding consistent results. To explain the [Fe/H] at −1.35 dex for COS 171 would require dilution of the SN Ia ejecta with ∼104
M
⊙ of material, which is expected for an SN remnant expanding into a warm interstellar medium with n ∼ 1 cm−3. In the future, finding more stars with the unique chemical signatures we highlight here will be important for constraining the rate and environments of sub-Chandrasekhar SNe Ia.
New species of the genus Mesocletodes Sars, 1909 from the deep Gulf of California (Copepoda, Harpacticoida)
Authors: Gómez Samuel
Published: April 2018

Investigations on the effects of the oxygen minimum zone on the distribution, abundance, and diversity of deep-sea benthic and pelagic fauna of the Gulf of California and Eastern Tropical Pacific has received attention recently. However, very little is known about the diversity of deep-sea benthic harpacticoids from this region, and only three species,AncorabolushendrickxiGómez & Conroy-Dalton, 2002,CeratonotuselongatusGómez & Díaz, 2017 andDendropsylluscaliforniensisGómez & Díaz, 2017, have been described so far. The genusMesocletodesSars, 1909 is one of the most common and abundant genera of deep-sea harpacticoids. This genus has been traditionally subdivided into two species groups, theabyssicolaand theinermisgroups, based on the presence/absence of a dorsal cuticular process on the cephalothorax and anal somite, but some species have been reported to deviate from this scheme. As a result of their investigations, other researchers proposed the monophyly of theabyssicolagroup, and suggested the probable monophyly of two other species-groups. In this paper, the descriptions of three new species of the genusMesocletodesfrom the deep sea of the Gulf of California are presented with some notes on their relationships with other species. Some comments on the monophyly of the genus are given.
Visionary leadership in the administrative staff of the Guapan educational unit
Authors: Martínez Molina Oscar
Published: April 2018

The purpose of the present study lies in determining the visionary leadership manifest in the administrative staff of the Guapan Educational Unit, with the research taking the form of a positivist descriptive research study that will deepen the knowledge of the variable that concerns us: visionary leadership. Through the application of field designs, the information was obtained directly from interaction with the subjects, who made up a population of (62) subjects, among whom were (07) administrators and (55) educational professionals, with the sample consisting of 38 instructors. The instrument used was an 18-item multiple-choice questionnaire (Almost always, Sometimes and Almost never), which was validated by three experts, with a reliability of 0.97, which demonstrates that it is highly reliable. The consolidation of this research showed with its results that the administrative staff engages in visionary leadership in the Guapan Educational Unit. The opinion of the instructional staff, however, shows just the opposite, judging that the administrators show weakness in visionary leadership. For this reason, guidelines are offered to the administrators of the state-funded private school located in the Cañar province, Azogues district, Guapan parish.
Investigation on Dynamic Impact Effect of Ultrasonic-Assisted Compression Test
Authors: Hu Jun , Shimizu Tetsuhide , Yang Ming
Published: April 2018

Ultrasonic-assisted metal forming have been studied numerously in conventional macro scale. However, ultrasonic dynamic impact effect, occurring in micro scale, has never been studied thoroughly, which makes the characteristics of material deformation more unpredictable in ultrasonic-assisted micro forming. The purpose of this study is to confirm the critical condition for occurrence of ultrasonic dynamic impact effect and to investigate the dimensional height dependency of ultrasonic dynamic impact effect on material deformation. In this paper, commercially pure aluminum 1100 with varying height (φ2×2mm, φ2×1.5mm, φ2×1mm) were selected for conventional static (without ultrasonic vibration) and ultrasonic-assisted compression tests. Ultrasonic-induced stress reduction was evaluated and the contour shape of deformed specimens was compared to investigate the ultrasonic dynamic impact effect on material deformation. The results showed that, as dimensional height of specimen decreased, ultrasonic vibration can reduce forming stress more effectively. In addition, a surprising anti-barreling shape and a significant contact surface area expansion were observed near contact surfaces in every specimen compressed with ultrasonic-assistance, indicating that additional plastic deformation can be produced by ultrasonic dynamic impact effect. An ultrasonic dynamic impact factor (y) is proposed and estimated by an exponential type trend line as y = 2.42e-1.48x for different dimensional specimen height (x) to quantify the ultrasonic dynamic impact effect. The promising prospect of ultrasonic vibration in micro-forming was demonstrated by the findings above, which helped to provide a basis to understand the underlying mechanism of ultrasonic-assisted micro forming and design the process in the future.
Geometric Design of Rectangular Cross-Sectional Springs
Authors: Hwang Yeong Maw , Lin D.S. , Lin Sheng Liang
Published: April 2018

In order to study the influence of the cross-sectional shape on the stiffness of a spring, a finite element analysis software DEFORM is used to simulate and analyze the torsion of rectangular cross-section bars. The material of the bar is TS1800 SAE9254 and the cross-section of aspect ratio (w / h) is 1.5. From literature it is known that when the rectangular section bar is twisted, the shear stress at the four corners is zero, so elliptical corners can decrease the volume and increase the stiffness with the same volume. Five levels for the long side of the elliptical corner are set as 1 to 5 mm, and 3 levels are set for the short side. Torsion of the rectangular section bars under 15 kinds of geometric designs are simulated to find the preferred cross-sectional shape design by evaluating the cross-sectional area, load, and the maximum shear stress. The objective of the design is obtaining a uniform stress distribution with a larger spring stiffness and lighter weight. The optimal cross section of the bars is established as the spring geometry, and the pre-loading processing of the spring is simulated. The required load and the maximum shear stress data are obtained. The effects of load, cross-sectional area and maximum shear stress on the springs performance are investigated.
The Numerical Simulation and Experiment Verification of the Large Aluminum Alloy Covering Part of Car Using Sequential Coupling Technology
Authors: Lang Li Hui , Zhang Quan Da , Alexandrov Sergei
Published: April 2018

Based on the large aluminum alloy covering part of car with characteristics such as complex shape and structure and the requirements of surface quality, in this paper, the covering part is formed by use of the combination of liquid medium forming with high pressure and local shaping with rigid mold which is also named as sequential coupling forming technology. It was analyzed from the aspect of the numerical simulation and experimental verification respectively. Firstly, the numerical simulation of the liquid medium forming with high pressure of the part was carried out using the special sheet forming software DYNAFORM, according to the results of numerical simulation, the key parameter such as loading path of liquid chamber pressure was optimized and the hydraulic test was carried out according to the optimal results. As a result, the parts with good surface quality were obtained. Then, in order to fully form the small features in the part which are difficult to form, reduce the equipment tonnage, and the dimensional accuracy of parts which have been formed were not affected, the method using a rigid mold to shape the local parts in the part was adopted, and the final part with good quality was obtained according to the experiment. Taking the final part as the study object, the experimental values and numerical simulation values of the wall thickness along the typical paths were measured and compared respectively. According to the comparison results of the wall thickness, the numerical simulation values have a good agreement with the experimental results, and the sequential coupling forming technology using the combination of liquid medium forming with high pressure and local shaping with rigid mold is verified feasible.
Analysis of Dieless Drawing to Form the End of Metal Wires under Proportional Shape Evolution with Slab Method
Authors: Fann Kuang-Jau , Yu Chia Feng , Chang Chun Hao
Published: April 2018

This study is to set a goal to create a model solving the temperature distribution and its evolution for the process of dieless drawing metal wire parts by using slab method and postulating that the wire end suffers a proportional deformation. The results from using a SUS304 stainless wire in 5 mm diameter dielessly drawn show that the highest temperature locates on the symmetry plane at the process beginning, so that the necking takes place there and an end will be formed securely. As a result, the method proposed by this study is feasible. In addition, for a given final shape of the metal wire end, there are many possibilities to get different temperature distribution and its evolution by setting different temperature boundary condition. The higher the boundary temperature set, the higher the temperature distribution, but the lower the drawing force needed.
Prediction of Shear Length in Blanking Process by Numerical Analysis
Authors: Sato Shusuke , Omiya Masaki
Published: April 2018

Blanking process has high productivity compared with other cutting processes. Because of this feature, the blanking process is used for the manufacture of automobile parts, electronic parts and so on. However, the blanking process is the process that leads to fracture. When the cutting surface are used as the functional surface, such as gears or cams, the precision of cutting surface is important and it can be improved by applying appropriate process conditions. The appropriate process conditions have been determined by repeating many experiments and this process is very inefficient. Owing to this background, the determination of the optimal process condition by numerical method such as the finite element method (FEM) is expected. In the previous studies, blanking process analyses of round blanking process which were modeled as 2D axisymmetric problem have been carried out and the cutting surface that coincided well with the experimental result was obtained. However, the blanking shape was not taken into consideration and they were not considering whether it can be applied to complicated shape expected to be applied in the future. In this study, blanking process analysis of quadrilateral blanking process was modeled as 2D plane strain problem and the applicability of various ductile fracture criteria was examined by comparing numerical results with experimental results based on shear length. As a result, there was little difference in the applicability of Cockcroft and Latham, Ayada, Brozzo ductile fracture criterion to the prediction of shear length under the current conditions.
Effect of Strain Path Change on Formability of TRIP Steels
Authors: Zhou Chi , Zhang Wen Tao , Zhang Sai Jun , Deng Jun Jie , Xia Qin Xiang
Published: April 2018

The effect of strain path change on formability of TRIP590 and TRIP780 was investigated experimentally. Two-step uniaxial tension tests, which consist of the first loading in the rolling direction (RD) and the second loading in the directions varied from RD to transverse direction (TD) in every 15º, were conducted. The evolution of strain rates inside and outside the localized necking zone were inspected by using DIC measuring technique. When the angle between the two loading directions was increased from 0º to 90 º, the subsequent hardening behavior in second step was transited from cross-loading type to Bauschinger type. The total elongation was increased when the two loading directions are close to each other and then it was decreased with the increase of angle. When the angle further increased to 90 º, the total elongation is increased again. It is believed that both of the martensite transformation and Bauschinger type transient has a positive impact on the formability of TRIP steels.
Drawing Force Optimization Research on Forming Parameters of Drawing Wire Rod with Rotating Die under Coulomb Friction
Authors: Chai Un Chin , Tzou Gow Yi , Tiong Ing Kiat
Published: April 2018

An optimization research based on the drawing force is done on several forming parameters of metal rod drawing through a rotating die under Coulomb friction. The metal rod and the rotating die are constructed in SolidWorks and imported into FEM simulation software named DEFORM 3D. In this study, the FEM simulation is carried out by using DEFORM 3D combining with Taguchi method to explore the effective stress, the effective strain, and the velocity field. The influence rank of parameters to the drawing force is obtained, and the optimal parameters’ combination is determined by using Taguchi method. Results show that the optimization of drawing force is achieved and the minimum drawing force is successfully obtained.
Dimensional Characteristics of Tailor Rolled Blanks Having Thickness Variations both in Longitudinal and Width Directions
Authors: Han Sang Wook , Jung Hee Seok , Woo Young Yun , Moon Young Hoon
Published: April 2018

Tailored blanks with different blank thicknesses are semi-finished parts that can be used to produce stamping parts having a real tailor-made solution. This study investigates a manufacturing process that can produce a tailored rolled blanks(TRB) having variable thickness variations both in longitudinal and width directions. The process was experimentally and numerically investigated using three types of the conventional blank and blanks having circular and square holes. To characterize the process, the deformation behaviors of blanks were intensively analyzed. In order to understand the effect of the blank shape on the manufacturing TRB, the strain behaviors was compared by numerical simulation. The results show that the hollow blanks have good formability in the manufacturing of TRB having variable thickness variations both in longitudinal and width directions compared with the conventional blank.
Mechanical and Microstructural Evolutions of the Laser Deposited Titanium Layers under Various Shielding Atmospheres
Authors: Hwang Tae Woo , Han Sang Wook , Seo Dong Myeong , Moon Young Hoon
Published: April 2018

Direct laser melting process is a kind of prototyping process whereby a 3-D part is built layer-wise by melting the metal powder with laser scanning. The properties of laser melted layer are found to be strongly dependent upon the types of shielding gas used. In this study, the effects of shielding gases on the mechanical and microstructural properties of the deposited titanium layers have been investigated. The laser remelting process has also been implemented at various shielding atmospheres to investigate the changes in surface roughness and hardness of deposited layers. The characterization of laser processing parameters, such as laser power, scan rate, gas flow rate, powder layer thickness, beam spot size and hatch distance, is proved to be useful in controlling the mechanical and microstructural properties of the deposited layer.
Investigation of a Two-Step Rotary Rim-Thickening Process of Disc-Like Blanks
Authors: Wang Dao Kuan , Jin Jun Song , Wang Xin Yun
Published: April 2018

A two-step rotary rim-thickening process of disc-like blanks was investigated by FE simulation and spinning experiments. The preforming shape of cross section for first step was designed as trapezium before forming rectangular-shape rim in the second step. The main factors influencing the blank forming in the first step were groove bottom height h1 and the inclination angle α of the roller. With the increase of h1 and α of the roller in FE simulation, the workpiece will be more prone to lose stability and cause defects. The forming limit diagram was obtained in first step, including stable forming zone, unstable forming zone and failed forming zone. Considering the stability and efficiency of thickening, four groups of h1 and α were selected for the second step simulation. Maximum rim thickness (h2) after second-step forming was 9 mm, obtained by trial and error in FE simulations. The spinning experiments were carried out to verify the validity of numerical simulation.
Two new species of Oobius (Hymenoptera: Encyrtidae) and their phylogenetic relationship with other congeners from northeastern Asia
Authors: Yao Yan-Xia , Duan Jian J. , Mottern Jason L. , Wang Xiao-Yi , Yang Zhong-Qi , Bauer Leah S. , Gates Michael W.
Published: April 2018

Two new species of egg parasitoids, Oobius saimaensis Yao and Mottern new species and Oobius fleischeri Yao and Duan new species (Hymenoptera: Encyrtidae), are described from eggs of Agrilus fleischeri Obenberger, 1925 (Coleoptera: Buprestidae). Agrilus fleischeri is a phloem-feeding woodborer of poplar (Populus Linnaeus; Salicaceae) in northeastern China. These two species can be distinguished morphologically as O. fleischeri has five tarsomeres and O. saimaensis has four tarsomeres. Although O. saimaensis is morphologically similar to its sympatric congener O. agrili Zhang and Hang, 2005, an important natural enemy of the invasive emerald ash borer, Agrilus planipennis Fairmaire, 1888, molecular phylogenetics and morphological data indicate that they are distinct species. Phylogenetic relationships among the new species and other closely related species are also inferred by using DNA sequence data from several ribosomal and mitochondrial genes. In addition, we expand the known distribution of Oobius primorskyensis Yao and Duan, 2016 to include South Korea.
Jong debuutdigter se ‘ope brief’ hou belofte in
Authors: Jacobs Ihette
Published: April 2018

No abstract available.
Seroprevalence of Toxoplasma gondii infection in goats and sheep in Zimbabwe
Authors: Hove T. , Lind P. , Mukaratirwa S.
Published: April 2018

Seroprevalence rates of Toxoplasma gondii anti-antibodies in adult goats and sheep from different parts of Zimbabwe were determined. A total of 225 (67.9 %) of the 335 serum samples tested were positive for anti-T. gondii IgG antibodies with the indirect fluorescent antibody test. There were differences in antibody seroprevalences among communal land goats from the different agro-ecological zones (Natural regions IIb and III: 80 and 96.7 %, respectively; Natural region IV: 65.9 %; Natural region V: 45 %; and Natural region III had a significantly higher seroprevalence than IV and V. The highest seroprevalences found in Natural regions II b and III are likely to be linked to the existence of more households and hence the possibility of a higher concentration of domestic cats that increases the chances of environmental contamination with their faeces harbouring T. gondii oocysts. The seroprevalence rate in sheep from a large commercial farm (10 %) was significantly lower than that of sheep reared under the communal grazing system (80 %). Overall, significantly higher proportions of seropositive animals had antibody titres of 1:50 (34.2 % of 225) and 1:100 (44 % of 225) as compared to the 9.8 % and 12 % with antibody titres of 1:200 and > 1:400, respectively.
The impact of family physician supply on district health system performance, clinical processes and clinical outcomes in the Western Cape Province, South Africa (2011–2014)
Authors: Chinhoyi Rekai L. , Zunza Moleen , Von Pressentin Klaus B.
Published: April 2018

Background: A revised family physician (FP) training programme was introduced in South Africa in 2007. A baseline assessment (2011) of the impact of FP supply on district health system performance was performed within the Western Cape Province, South Africa. The impact of an increased FP supply within this province required re-evaluation.Aim: To assess the impact of FP supply on indicators of district health system performance, clinical processes and clinical outcomes in the Western Cape Province. The objectives were to determine the impact of FPs, nurses, medical officers (MOs) and other specialists.Setting: The study sample included all five rural districts and eight urban subdistricts of the Western Cape Province.Methods: A secondary analysis was performed on routinely collected data from the Western Cape Department of Health from 01 March 2011 until 30 April 2014.Results: The FP supply did not significantly impact the indicators analysed. The supply of nurses and MOs had an impact on some of the indicators analysed.Conclusion: This study did not replicate the positive associations between an increase in FP supply and improved health indicators, as described previously for high-income country settings. The impact of FP supply on clinical processes, health system performance and outcome indicators in the Western Cape Province was not statistically significant. Future re-evaluation is recommended to allow for more time and an increase in FP supply.
Concentration and variability of ice nuclei in the subtropical maritime boundary layer
Authors: Welti André , Müller Konrad , Fleming Zoë L. , Stratmann Frank
Published: April 2018

Abstract. Measurements of the concentration and variability of ice
nucleating particles in the subtropical maritime boundary layer are reported.
Filter samples collected in Cabo Verde over the period 2009–2013 are
analyzed with a drop freezing experiment with sensitivity to
detect the few rare ice nuclei active at low supercooling. The data set is
augmented with continuous flow diffusion chamber measurements at temperatures
below −24 ∘C from a 2-month field campaign in Cabo Verde in 2016.
The data set is used to address the following questions: what are typical
concentrations of ice nucleating particles active at a certain temperature?
What affects their concentration and where are their sources? Concentration
of ice nucleating particles is found to increase exponentially by 7 orders of
magnitude from −5 to −38 ∘C. Sample-to-sample variation in the
steepness of the increase indicates that particles of different origin, with
different ice nucleation properties (size, composition), contribute to the
ice nuclei concentration at different temperatures. The concentration of ice
nuclei active at a specific temperature varies over a range of up to 4 orders
of magnitude. The frequency with which a certain ice nuclei concentration is
measured within this range is found to follow a lognormal
distribution, which can be explained by random dilution during transport. To
investigate the geographic origin of ice nuclei, source attribution of air
masses from dispersion modeling is used to classify the data into seven
typical conditions. While no source could be attributed to the ice nuclei
active at temperatures higher than −12 ∘C, concentrations at lower
temperatures tend to be elevated in air masses originating from the Sahara.
Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect
Authors: Cossa Daniel , Heimbürger Lars-Eric , Pérez Fiz F. , García-Ibáñez Maribel I. , Sonke Jeroen E. , Planquette Hélène , Lherminier Pascale , Boutorh Julia , Cheize Marie , Menzel Barraqueta Jan Lukas , Shelley Rachel , Sarthou Géraldine
Published: April 2018

Abstract. We report here the results of total mercury (HgT) determinations along the 2014 Geotraces Geovide cruise (GA01 transect) in the North Atlantic Ocean (NA) from Lisbon (Portugal) to the coast of Labrador (Canada). HgT concentrations in unfiltered samples (HgTUNF) were log-normally distributed and ranged between 0.16 and 1.54 pmol L−1, with a geometric mean of 0.51 pmol L−1 for the 535 samples analysed. The dissolved fraction (< 0.45 µm) of HgT (HgTF), determined on 141 samples, averaged 78 % of the HgTUNF for the entire data set, 84 % for open seawaters (below 100 m) and 91 % if the Labrador Sea data are excluded, where the primary production was high (with a winter convection down to 1400 m). HgTUNF concentrations increased eastwards and with depth from Greenland to Europe and from subsurface to bottom waters. The HgTUNF concentrations were similarly low in the subpolar gyre waters ( ∼  0.45 pmol L−1), whereas they exceeded 0.60 pmol L−1 in the subtropical gyre waters. The HgTUNF distribution mirrored that of dissolved oxygen concentration, with highest concentration levels associated with oxygen-depleted zones. The relationship between HgTF and the apparent oxygen utilization confirms the nutrient-like behaviour of Hg in the NA. An extended optimum multiparameter analysis allowed us to characterize HgTUNF concentrations in the different source water types (SWTs) present along the transect. The distribution pattern of HgTUNF, modelled by the mixing of SWTs, show Hg enrichment in Mediterranean waters and North East Atlantic Deep Water and low concentrations in young waters formed in the subpolar gyre and Nordic seas. The change in anthropogenic Hg concentrations in the Labrador Sea Water during its eastward journey suggests a continuous decrease in Hg content in this water mass over the last decades. Calculation of the water transport driven by the Atlantic Meridional Overturning Circulation across the Portugal–Greenland transect indicates northward Hg transport within the upper limb and southward Hg transport within the lower limb, with resulting net northward transport of about 97.2 kmol yr−1.
Ideological Becoming in Socialist and Post-Socialist Childhood and Schooling from a Dialogic Framework
Authors: Matusov Eugene , Marjanovic-Shane Ana , Chen Lei , Tesar Marek
Published: April 2018

This special DPJ issue aims to bring together those who had first-hand experiences with or conduct educational and/or historical research with children and schooling in socialist and post-socialist societies. Socialist and post-socialist childhood and schooling in socialist and post-socialist education systems are usually assumed to be monolithic and authoritarian, far from dialogic. However, by reflecting on our own or others’ experiences, narratives and observations regarding the socialist and post-socialist childhood, we realized that our memories, experiences and observations might offer unique and enriching soil for understanding, exploring, reflecting, and critiquing dialogic pedagogical theories. Through this special issue, we hope to expand the scholarship of this community to the territory of a space and time that were not previously examined (sufficiently) for dialogic pedagogy by creating interests and forums for dialogues.
Problèmes de traduction-d’individuation dans les Fous de Bassant
Authors: Woodward Servanne
Published: April 2018

L’idée d’individuation, telle que définie par Pierre Bourdieu (Les règles de l'art 1992) et Gilbert Simondon (1989) dans les domaines littéraires et sociologiques, est utilisée ici pour définir le processus de traduction d’un passage des Fous de Bassant d’Anne Hébert, dont le drame d’une communauté anglophone s’exprime en français, et dont le « retour » sur l’expression anglaise par une traduction du français vers l’anglais pose problème. Le protagoniste principal (l’étranger que son frère jumeau ne reconnaît que lorsqu’il décline son nom) se complaît dans une position marginale ou aliénante pour la société avec laquelle il cultive une position antagoniste. L’aliénation calculée du protagoniste qui demeure dans le flou représentationnel donne un statut particulier au rapport « étranger » de l’individuation, tant au niveau du lexique textuel, qu’au niveau des caractéristiques composant le personnage. La position d’immigrant pris entre deux langues et entre terre et mer est ici celle du colon dans un milieu hostile qui ne peut trouver ses « racines » que par l’enterrement ou la noyade.
From Principals' Inspirational Vision Content and Potential Absorptive Capacity to Realized Absorptive Capacity: Predicting Teacher Absenteeism
Authors: Da'as Rima'a , Qadach Mowafaq
Published: April 2018

This paper builds upon the theoretical framework developed by Zahra and George (2002) to empirically explore, first,the moderator effect of principals' inspirational vision content as a social mechanism that reduces the gap betweenpotential absorptive capacity (PACAP; the ability to acquire and assimilate external knowledge) and realizedabsorptive capacity (RACAP; the ability to transform and exploit this external knowledge to school processes); andsecond, the relationship between RACAP and long-term school outcomes (teachers' absenteeism 1 year later). Basedon a sample of 600 teachers from 100 elementary schools in Israel, results showed that the relationship betweenPACAP and RACAP is not conditioned by principals' inspirational vision content. The latter and PACAP predictedRACAP separately. Further, RACAP was negatively correlated with teacher absenteeism. This study provides adeeper understanding of the ACAP model in the school context and opens new avenues to exploring the socialintegration mechanism between PACAP and RACAP. It also adds a new construct to predict teacher absenteeismover the long term.