bluuebunny/crossref_metadata_2025 huggingface dataset:
Compression Fracture of CFRP Laminates Containing Stress Intensifications
Authors: Leopold Christian , Schütt Martin , Liebig Wilfried , Philipkowski Timo , Kürten Jonas , Schulte Karl , Fiedler Bodo
Published: September 2017

For brittle fracture behaviour of carbon fibre reinforced plastics (CFRP) under compression, several approaches exist, which describe different mechanisms during failure, especially at stress intensifications. The failure process is not only initiated by the buckling fibres, but a shear driven fibre compressive failure beneficiaries or initiates the formation of fibres into a kink-band. Starting from this kink-band further damage can be detected, which leads to the final failure. The subject of this work is an experimental investigation on the influence of ply thickness and stacking sequence in quasi-isotropic CFRP laminates containing stress intensifications under compression loading. Different effects that influence the compression failure and the role the stacking sequence has on damage development and the resulting compressive strength are identified and discussed. The influence of stress intensifications is investigated in detail at a hole in open hole compression (OHC) tests. A proposed interrupted test approach allows identifying the mechanisms of damage initiation and propagation from the free edge of the hole by causing a distinct damage state and examine it at a precise instant of time during fracture process. Compression after impact (CAI) tests are executed in order to compare the OHC results to a different type of stress intensifications. Unnotched compression tests are carried out for comparison as a reference. With this approach, a more detailed description of the failure mechanisms during the sudden compression failure of CFRP is achieved. By microscopic examination of single plies from various specimens, the different effects that influence the compression failure are identified. First damage of fibres occurs always in 0°-ply. Fibre shear failure leads to local microbuckling and the formation and growth of a kink-band as final failure mechanisms. The formation of a kink-band and finally steady state kinking is shifted to higher compressive strains with decreasing ply thickness. Final failure mode in laminates with stress intensification depends on ply thickness. In thick or inner plies, damage initiates as shear failure and fibre buckling into the drilled hole. The kink-band orientation angle is changing with increasing strain. In outer or thin plies shear failure of single fibres is observed as first damage and the kink-band orientation angle is constant until final failure. Decreasing ply thickness increases the unnotched compressive strength. When stress intensifications are present, the position of the 0°-layer is critical for stability under compression and is thus more important than the ply thickness. Central 0°-layers show best results for OHC and CAI strength due to higher bending stiffness and better supporting effect of the adjacent layers.
Design and Antiproliferative Evaluation of Novel Sulfanilamide Derivatives as Potential Tubulin Polymerization Inhibitors
Authors: Fu Dong-Jun , Liu Ji-Feng , Zhao Ruo-Han , Li Jia-Huan , Zhang Sai-Yang , Zhang Yan-Bing
Published: September 2017

A series of sulfanilamide-1,2,3-triazole hybrids were designed by a molecular hybridization strategy and evaluated for antiproliferative activity against three selected cancer cell lines (MGC-803, MCF-7 and PC-3). The detailed structure-activity relationships for these sulfanilamide-1,2,3-triazole hybrids were investigated. All these sulfanilamide-1,2,3-triazole hybrids exhibited moderate to potent activity against all cell lines. In particular 4-methyl-N-((1-(3-phenoxybenzyl)-1H-1,2,3-triazol-4-yl)methyl)benzenesulfonamide (11f) showed the most potent inhibitory effect against PC-3 cells, with an IC50 value of 4.08 μM. Furthermore, the tubulin polymerization inhibitory activity in vitro of compound 11f was 2.41 μM. These sulfanilamide hybrids might serve as bioactive fragments for developing more potent antiproliferative agents.
Anti-Melanogenic Effects of Flavonoid Glycosides from Limonium tetragonum (Thunb.) Bullock via Inhibition of Tyrosinase and Tyrosinase-Related Proteins
Authors: Lee Seul-Gi , Karadeniz Fatih , Seo Youngwan , Kong Chang-Suk
Published: September 2017

Overproduction and stimulation of tyrosinase result in increased melanogenesis of which several skin disorders such as freckles, spots, and hyperpigmentation appear as complications. Limonium tetragonum is a halophyte well-known for its antioxidative properties. This study investigated the anti-melanogenic effects of solvent-partitioned L. tetragonum extracts (LTEs) and its bioactive constituents, two isolated flavonoid glycosides. Current study followed a set of experiments on B16-F10 mouse melanoma cell model with a focus on tyrosinase activity and production. The anti-melanogenic capacity of LTEs was confirmed by their tyrosinase inhibitory effects, prevention of DOPA oxidation, and suppression of melanin production. The inhibition of tyrosinase and DOPA oxidation by LTEs was suggested to be related with the downregulation of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2, verified with mRNA and protein expression levels. Among all tested LTEs, 85% aq. MeOH and n-BuOH were found to be the most active fractions which later yielded the two known compounds, myricetin 3-galactoside and quercetin 3-O-β-galactopyronaside. The anti-melanogenic potential of the compounds were confirmed by their tyrosinase inhibitory effects. These results suggested that L. tetragonum may serve as a potential source of bioactive substances with effective anti-melanogenesis properties.
Effect of Different Activated Carbon as Carrier on the Photocatalytic Activity of Ag-N-ZnO Photocatalyst for Methyl Orange Degradation under Visible Light Irradiation
Authors: Chen Xiaoqing , Wu Zhansheng , Gao Zhenzhen , Ye Bang-Ce
Published: September 2017

In order to enhance the photodegradation of methyl orange (MO) by ZnO under visible light irradiation, ZnO nanoparticles co-doped with Ag and N and supported on activated carbon (AC) with different properties were synthesized through the sol-gel method. The prepared photocatalysts were characterized in terms of the structure and properties through X-ray diffraction, N2 adsorption-desorption, ultraviolet-visible (UV-vis), diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, photoluminescence, and electron spin resonance. The photocatalytic activities of these photocatalysts followed the order: Ag-N-ZnO/ACs > Ag-N-ZnO > N, or Ag single-doped ZnO > commercial ZnO. This result was attributed to the small particle size, large surface area, narrow band gap, and high charge separation of Ag-N-ZnO/ACs. The Ag-N-ZnO/coconut husk activated carbon (Ag-N-ZnO/CHAC) exhibited the highest degradation efficiency of 98.82% for MO under visible light irradiation. This outcome was due to the abundant pore structure of Ag-N-ZnO/CHAC, resulting in stronger adsorption than that of other Ag-N-ZnO/ACs. Moreover, the degradation of MO on photocatalysis followed first order kinetics. The reactive species ·OH and ·O2− played more important roles in the photocatalytic degradation of MO over composite photocatalyst. Ag-N-ZnO/CHAC photocatalyst exhibited higher photocatalytic activity than unsupported Ag-N-ZnO after five recycling runs.
Erratum: History of U.S. Iodine Fortification and Supplementation; Nutrients 2012, 4, 1740–1746
Authors: Leung Angela , Braverman Lewis , Pearce Elizabeth
Published: September 2017

The authors requested the following corrections to their paper [1].[...]
The Effect of Moisture on Cellulose Nanocrystals Intended as a High Gas Barrier Coating on Flexible Packaging Materials
Authors: Fotie Ghislain , Rampazzo Riccardo , Ortenzi Marco , Checchia Stefano , Fessas Dimitrios , Piergiovanni Luciano
Published: September 2017

Cellulose nanocrystals (CNCs) exhibit outstanding gas barrier properties, which supports their use as a biobased and biodegradable barrier coating on flexible food packaging materials. As highly hydrophilic biopolymers, however, CNCs have a strong sensitivity to water that can be detrimental to applications with fresh foods and in moist conditions due to the loss of barrier properties. In this work, the oxygen and water vapor permeability of polyethylene terephthalate (PET) films coated with CNCs obtained from cotton linters were measured at varying levels of relative humidity, both in adsorption and desorption, and from these data, the diffusion and solubility coefficients were estimated. Therefore, the characterization of CNCs was aimed at understanding the fundamentals of the water-CNCs interaction and proposing counteractions. The CNCs’ moisture absorption and desorption isotherms at 25 °C were collected in the range of relative humidity 0–97% using different techniques and analyzed through GAB (Guggenheim-Anderson-de Boer) and Oswin models. The effects of moisture on the water status, following the freezable water index, and on the crystal structure of CNCs were investigated by Differential Scanning Calorimetry and by X-ray Powder Diffraction, respectively. These findings point to the opportunity of coupling CNCs with hydrophobic layers in order to boost their capabilities as barrier packaging materials.
Dazzling Displays and Hidden Departures: Bodhisattva Pedagogy as Performance in the Biographies of Two Twentieth Century Tibetan Buddhist Masters
Authors: Pitkin Annabella
Published: September 2017

This article, part of a special issue on pedagogy and performance in Tibetan Buddhism, explores two closely-related yet apparently opposite Tibetan repertoires of virtuoso Buddhist mastery as sites of performative pedagogy. One of these modes of Buddhist mastery is connected with the ideal virtuoso figure of the yogic siddha, or druptop (Tib. grub thob), and with remarkable manifestations of yogic prowess (what are sometimes called yogic “miracles” in English). The other mode is connected with the ideal of renunciation, and the Tibetan Buddhist virtuoso figure of the renunciant hermit-wanderer, or chatralwa (Tib. bya bral ba). In Indic and Tibetan literature, both of these repertoires of Buddhist mastery are classically associated with a bodhisattva’s teaching activity in the world, and with a bodhisattva’s use of many kinds of skillful means (Skt. upāya; Tib. thabs) to develop individuals on the Buddhist path. (A bodhisattva, in Mahayana Buddhist terms, is someone who has vowed to achieve Buddhahood to benefit others.) I explore how these related modes of virtuoso pedagogical performance emerge in oral and textual life stories of two notable twentieth-century Tibetan masters. These modes of virtuoso Buddhist pedagogy and Tibetan ways of talking about them challenge our understandings of what it means to “perform” and what it means to “renounce,” with renunciation emerging as a guarantor of the genuineness of someone’s altruism.
An IMM-Aided ZUPT Methodology for an INS/DVL Integrated Navigation System
Authors: Yao Yiqing , Xu Xiaosu , Xu Xiang
Published: September 2017

Inertial navigation system (INS)/Doppler velocity log (DVL) integration is the most common navigation solution for underwater vehicles. Due to the complex underwater environment, the velocity information provided by DVL always contains some errors. To improve navigation accuracy, zero velocity update (ZUPT) technology is considered, which is an effective algorithm for land vehicles to mitigate the navigation error during the pure INS mode. However, in contrast to ground vehicles, the ZUPT solution cannot be used directly for underwater vehicles because of the existence of the water current. In order to leverage the strengths of the ZUPT method and the INS/DVL solution, an interactive multiple model (IMM)-aided ZUPT methodology for the INS/DVL-integrated underwater navigation system is proposed. Both the INS/DVL and INS/ZUPT models are constructed and operated in parallel, with weights calculated according to their innovations and innovation covariance matrices. Simulations are conducted to evaluate the proposed algorithm. The results indicate that the IMM-aided ZUPT solution outperforms both the INS/DVL solution and the INS/ZUPT solution in the underwater environment, which can properly distinguish between the ZUPT and non-ZUPT conditions. In addition, during DVL outage, the effectiveness of the proposed algorithm is also verified.
Improved Range Estimation Model for Three-Dimensional (3D) Range Gated Reconstruction
Authors: Chua Sing , Guo Ningqun , Tan Ching , Wang Xin
Published: September 2017

Accuracy is an important measure of system performance and remains a challenge in 3D range gated reconstruction despite the advancement in laser and sensor technology. The weighted average model that is commonly used for range estimation is heavily influenced by the intensity variation due to various factors. Accuracy improvement in term of range estimation is therefore important to fully optimise the system performance. In this paper, a 3D range gated reconstruction model is derived based on the operating principles of range gated imaging and time slicing reconstruction, fundamental of radiant energy, Laser Detection And Ranging (LADAR), and Bidirectional Reflection Distribution Function (BRDF). Accordingly, a new range estimation model is proposed to alleviate the effects induced by distance, target reflection, and range distortion. From the experimental results, the proposed model outperforms the conventional weighted average model to improve the range estimation for better 3D reconstruction. The outcome demonstrated is of interest to various laser ranging applications and can be a reference for future works.
Gender Difference in the Influence of Family Interaction and Parenting Behaviours on Youth Sexual Intention
Authors: Muhammad Noor , Tohid Hizlinda , Omar Khairani , Mohd. Amin Rahmah , Shamsuddin Khadijah
Published: September 2017

This paper presents the differences in family interaction and parenting behaviours and their influence on sexual intention among male and female youths aged 18 to 22 years. The results presented are based on data collected from unmarried college students in Klang Valley, Malaysia. Despite being in a country where premarital sexual activity is not an accepted behaviour, 18% of the 422 male and 1.4% of the 566 female students indicated their intention to perform sexual activity. Compared to females, males had more allowance of autonomy from parents and lesser parental monitoring, paternal care, parent-youth communication on sexual issues, and family connectedness. Both genders perceived that they received similar levels of parental control. In male youths, having high maternal control (OR: 1.19, 95% CI: 1.03–1.38) and family modelling behaviour (OR: 2.25, 95% CI: 1.19–4.25) increased their odds of having sexual intention while having high parent-youth communication on sex (OR: 0.89, 95% CI: 0.81–0.99) reduced their odds of having sexual intention. For female youths, having a high level of family connectedness (OR: 0.76, 95% CI: 0.59–0.97) was a protective factor against sexual intention. In conclusion, sexual intention is higher among males compared to females. The influence of family interaction and parenting behaviours on youth sexual decision varied across gender. This study highlighted the possibility of using different parenting approaches in tackling premarital sexual activity among youths.
Structural model of silicene-like nanoribbons on a Pb-reconstructed Si(111) surface
Authors: Stępniak-Dybala Agnieszka , Krawiec Mariusz
Published: September 2017

A structural model of the recently observed silicene-like nanoribbons on a Pb-induced √3 × √3 reconstructed Si(111) surface is proposed. The model, which is based on first principles density functional theory calculations, features a deformed honeycomb structure directly bonded to the Si(111) surface underneath. Pb atoms stabilize the nanoribbons, as they passivate the uncovered substrate, thus lower the surface energy, and suppress the nanoribbon–substrate interaction. The proposed structural model reproduces well all the experimental findings.
CONGESTION EFFECTS OF AUTONOMOUS TAXI FLEETS
Authors: Maciejewski Michal , Bischoff Joschka
Published: September 2017

Fleets of shared Autonomous Vehicles (AVs) could replace private cars by providing a taxi-like service but at a cost similar to driving a private car. On the one hand, large Autonomous Taxi (AT) fleets may result in increased road capacity and lower demand for parking spaces. On the other hand, an increase in vehicle trips is very likely, as travelling becomes more convenient and affordable, and additionally, ATs need to drive unoccupied between requests. This study evaluates the impact of a city-wide introduction of ATs on traffic congestion. The analysis is based on a multi-agent transport simulation (MATSim) of Berlin (Germany) and the neighbouring Brandenburg area. The central focus is on precise simulation of both real-time AT operation and mixed autonomous/conventional vehicle traffic flow. Different ratios of replacing private car trips with AT trips are used to estimate the possible effects at different stages of introducing such services. The obtained results suggest that large fleets operating in cities may have a positive effect on traffic if road capacity increases according to current predictions. ATs will practically eliminate traffic congestion, even in the city centre, despite the increase in traffic volume. However, given no flow capacity improvement, such services cannot be introduced on a large scale, since the induced additional traffic volume will intensify today’s congestion.
IDENTIFYING DOMINANT STAKEHOLDER PERSPECTIVES ON URBAN FREIGHT POLICIES: A Q-ANALYSIS ON URBAN CONSOLIDATION CENTRES IN THE NETHERLANDS
Authors: Duin Ron van , Slabbekoorn Marijn , Tavasszy Lori , Quak Hans
Published: September 2017

Cities’ sustainability strategies seem to aim at the reduction of the negative impacts of urban freight transport. In the past decades, many public and private initiatives have struggled to gain broad stakeholder support and thus remain viable. Researchers and practitioners have only recently recognised stakeholder acceptance of urban freight solutions as a challenge. A first step in achieving convergence is to understand stakeholder needs, preferences and viewpoints. This paper proposes and applies an approach to identify the main stakeholder perspectives in the domain of urban freight transport. We use Q-methodology, which originates from social sciences and psychology, to record subjective positions and identify the dominant ones. We explain the approach, operationalise the method for the domain of urban freight transport and apply it to stakeholder groups in the Netherlands. We find four dominant perspectives, reflecting how stakeholders normally take positions in the urban freight dialogue. Important findings concern disparities between industry associations and some of their membership, divergent views about the expected role of public administration, and the observation that the behaviour of shippers and Logistics Service Providers (LSP) appears to be inconsistent with their beliefs. All these factors together can act as a barrier to the implementation of urban freight consolidation concepts. The Q-methodology is valuable for eliciting perspectives in urban freight and is a promising tool to facilitate stakeholder dialogue and, eventually, convergence.
WHEEL–RAIL WEAR INVESTIGATION ON A HEAVY HAUL BALLOON LOOP TRACK THROUGH SIMULATIONS OF SLOW SPEED WAGON DYNAMICS
Authors: Quan SUN Yan , SPIRYAGIN Maksym , COLE Colin , NIELSEN Dwayne
Published: September 2017

Heavy haul railway track infrastructure are commonly equipped with balloon loops to allow trains to be loaded/unloaded and/or to reverse the direction of travel. The slow operational speed of trains on these sharp curves results in some unique issues regarding the wear process between wheels and rails. A wagon dynamic system model has been applied to simulate the dynamic behaviour in order to study the wheel–rail contact wear conditions. A wheel–rail wear index is used to assess the wear severity. The simulation shows that the lubrication to reduce the wheel–rail contact friction coefficient can significantly reduce the wear severity. Furthermore, the effects of important parameters on wheel–rail contact wear including curve radius, wagon speed and track superelevation have also been considered.
Kinetic Cascade in Solar-wind Turbulence: 3D3V Hybrid-kinetic Simulations with Electron Inertia
Authors: Cerri Silvio Sergio , Servidio Sergio , Califano Francesco
Published: September 2017

Understanding the nature of the turbulent fluctuations below the ion gyroradius in solar-wind (SW) turbulence is a great challenge. Recent studies have been mostly in favor of kinetic Alfvén wave (KAW)-type fluctuations, but other kinds of fluctuations with characteristics typical of magnetosonic, whistler, and ion-Bernstein modes could also play a role depending on the plasma parameters. Here, we investigate the properties of the subproton-scale cascade with high-resolution hybrid-kinetic simulations of freely decaying turbulence in 3D3V phase space, including electron inertia effects. Two proton plasma beta are explored: the “intermediate” β

p
 = 1 and “low” β

p
 = 0.2 regimes, both typically observed in the SW and corona. The magnetic energy spectum exhibits

and

power laws at β

p
 = 1, while they are slightly steeper at β

p
 = 0.2. Nevertheless, both regimes develop a spectral anisotropy consistent with

at

and pronounced small-scale intermittency. In this context, we find that the kinetic-scale cascade is dominated by KAW-like fluctuations at β

p
 = 1, whereas the low-β case presents a more complex scenario suggesting the simultaneous presence of different types of fluctuations. In both regimes, however, a possible role of the ion-Bernstein-type fluctuations at the smallest scales cannot be excluded.
Hemodialysis Access Choice: Impact of Health Literacy
Authors: Mazarova Andrea , Hiremath Swapnil , Sood Manish M. , Clark Edward G. , Brown Pierre Antoine , Bugeja Ann L. , England Grant L. , Zimmerman Deborah
Published: September 2017

Background:

Hemodialysis patients need to make decisions about vascular access and diet that they may not fully understand. In this study, we hypothesized that patients with low health literacy are likely to choose a central venous catheter (CVC) and have higher serum potassium (K), serum phosphate (P), and inter-dialysis weight gains (IDWG).

Objective:

Primarily, the study sought to describe the health literacy of patients treated with hemodialysis in a Canadian tertiary care center. The secondary objective was to describe the association between health literacy and permanent vascular access choice, hyperkalemia, hyperphosphatemia, and IDWG.

Methods:

Adult patients receiving hemodialysis for more than 6 months were included. Health literacy was assessed with the Newest Vital Sign (NVS) test. Vascular access type and reasons for CVC use were determined. Serum K, P, and IDWG were collected retrospectively for 6 months. Student's
t
test and logistic regression were used to determine the association between health literacy (NVS score < 4 versus ≥ 4) and CVC choice, hyperkalemia, hyperphosphatemia, and high IDWG.

Key Results:

Fifty-six patients were involved. The average NVS score was 2.9. Overall, 66% of the patients had a CVC; one-third had chosen this access themselves. Poor control of K, P, and IDWG was experienced by 27%, 55%, and 36% of patients, respectively. The average NVS score was lower for patients choosing a CVC (
p
= .001), but not different for those with higher K, P, or IDWG. None of the patients who chose a CVC had adequate health literacy (NVS ≥ 4).

Conclusions:

Patients with low health literacy, who are eligible for both surgically created vascular access (fistula or graft) and CVC, are more likely to refuse fistula/graft creation compared to patients with adequate health literacy. Different educational strategies for such patients may help in appropriate decision-making.

[
Health Literacy Research and Practice
. 2017;1(3):e136–e144.]

Plain Language Summary:

This study suggests that more than one-half of patients who receive hemodialysis may not understand all the information provided by their health care team. Despite a higher risk of complications with a central venous catheter, patients with lower health literacy prefer the catheter over fistula as their blood access for hemodialysis. We need to explore patient education to ensure that information is easy to understand.
Experimental Investigation of Failure Modes for Sandwich Beams
Authors: Marșavina Liviu , Şerban Dan Andrei , Pop Camelia , Negru Radu
Published: September 2017

In this paper, the mechanical behavior in three-point bending was investigated for four different sandwich beams composed of aluminum alloy 1050 H24 faces and Necuron rigid polyurethane foams. The tests were conducted according to the recommendations of ASTM C393-00. Three different failure modes were observed (yielding of faces, face and core indentation and shear of core), being in accordance with the modes deducted from the calculated values of bending and shear stresses.
A Numerical Model for the Simulation of Fatigue Induced Damage Onset and Evolution
Authors: Riccio Aniello , Esposito Francesco , Sellitto Andrea
Published: September 2017

In this work, a numerical model for the simulation of the onset and propagation of fatigue induced damages through a GFRP panel loaded in tension is presented. The model has been validated by numerical/experimental comparisons in terms of stiffness reduction over the number of loading cycles, considering three different applied loads. Finally, the model has been adopted to study the damage behaviour of a panel with a central notch damage.
On the Modelling of Creep Fracture and Fatigue
Authors: Kauppila P. , Kouhia Reijo , Ojanperä J. , Saksala T. , Sorjonen T.
Published: September 2017

In this paper, a thermodynamically consistent formulation for the analysis of creep fracture and fatigue is presented. The model is described via two potential functions, the specific Helmholtz free energy and the complementary dissipation potential. Isotropic damage variable is used to describe the degradation of the material. In addition, the use of creep parameters, like Monkman-Grant and Larson-Miller parameters are discussed and their relation to the proposed model are derived. Developed model is implemented as a user subroutine to the commercial finite element code ANSYS and an example case of practical interest is shown.
The Effect of Interface Geometry on the Mechanical Behavior of Adhesive Joints
Authors: Razavi Nima , Peron M. , Torgersen J. , Berto F.
Published: September 2017

The role of sinusoid interface shape on the load bearing capacity of the adhesively bonded single lap joints has been investigated experimentally. The experimental results showed that the interface non-flatness can considerably influence the adhesive joint strength. The main parameters that can affect the load bearing of the non-flat joints are wave heights, wave lengths and also mechanical properties of adhesives and adherends. In this paper, the effect of wave length was evaluated as the key variable parameter. According to the experimental results for the best studied case, non-flat sinusoid single lap joints had about 51% higher load bearing compared to the conventional flat single lap joints.
Effect of Temperature on Fatigue Strength Characteristic and Fatigue Mechanism in Laser Welded Dissimilar Stainless Steels Joint
Authors: Miyashita Yukio , Iraha Hideto , Narita Yu , Iizawa Yuki
Published: September 2017

Fatigue strength characteristic of laser welded joint between austenitic stainless steel and ferritic stainless steel was studied at room temperature and 300 °C.The results showed that fatigue strength at 300°C was higher than that at room temperature in lower applied stress amplitude region. Fatigue crack mainly initiated at stress concentration part at room temperature. However, fatigue crack origin changed toward to the base material and the heat affected zone with increasing testing temperature. Increase in ductility of the base material and the weld metal induced by increasing testing temperature reduces stress concentration effect and resulted in change in fatigue mechanism. Appropriate weld position in a component with temperature gradient can be considered by minimizing the effect of stress concentration and taking into account degradation of strength due to increase in temperature.
Optimization Methodology for an Automotive Cross-Member in Composite Material
Authors: Lo Presti I. , Cavazzoni L. , Calacci Fabio , Mantovani Sara
Published: September 2017

Optimization methods are useful and effective techniques for the design and development of components from the weight reduction point of view. This paper presents an optimization methodology applied to the front cross-member of a Maserati chassis for metal replacement application with the objective of the minimization of the mass of the structure using composite materials. Firstly, a topological optimization of the front side of the vehicle is performed, and the available design space is considered to determine the optimal load path of the design volume and, consequently, to assess a preliminary geometry of the component under scrutiny. Secondly, free-size optimization of the preliminary cross-member design is developed, initially neglecting and subsequently considering the manufacturing constraints. In addition, a linear analysis of the cross-member, modeled as a rigid component, is carried out to evaluate the maximum contribution of this component on the structural performance of the front side of the vehicle. Finally, size and shuffle optimizations are carried out on the new design concept to determine the number and the thickness of the composite plies, and the optimal stacking sequence, respectively, in order to fulfill the structural requirements. A comparison between the new composite structure and the aluminium Maserati cross-member is presented.
Structural Analysis for Estimating Damage Behavior of Double Hull under Ice-Grounding Scenario Models
Authors: Prabowo Aditya Rio , Sohn Jung Min , Byeon Jung Hoon , Bae Dong Myung , Zakki Ahmad Fauzan , Cao Bo
Published: September 2017

Demand to increase safety for water transportation, namely ship is continuously rising as various accidental loads may threat condition of target structure, i.e. ship. Several possibilities of impact scenario can occur with various indenters, for example stranding to a grounded ice. In this work, a study of structural behaviour accounting for interaction between the ship structure and indenter is conducted. Numerical simulation is performed using finite element method to estimate damage extent of the double bottom. In analysis, the indenter for grounding scenario is applied by characteristic of the ice properties to obtain estimated response of the structure in experiencing impact on polar territory. Impact scenario is defined into three different locations, namely girder and space between two girders. Finally, tendency of the damage per destroyed component is summarized.
Damage-Involved Structural Pounding in Bridges under Seismic Excitation
Authors: Jankowski Robert
Published: September 2017

During severe earthquakes, pounding between adjacent superstructure segments of highway elevated bridges was often observed. It is usually caused by the seismic wave propagation effect and may lead to significant damage. The aim of the present paper is to show the results of the numerical analysis focused on damage-involved pounding between neighbouring decks of an elevated bridge under seismic excitation. The analysis was carried out using a lumped mass structural model with every deck element discretized as a SDOF system. Pounding was simulated by the use of impact elements which become active when contact is detected. The linear viscoelastic model of collision was applied allowing for dissipation of energy due to damage at the contact points of colliding deck elements. The results show that pounding may substantially modify the behaviour of the analysed elevated bridge. It may increase the structural response or play a positive role, and the response depends on pattern of collisions between deck elements. The results also indicate that a number of impacts for a small in-between gap size is large, whereas the value of peak pounding force is low. On the other hand, the pounding force time history for large gap values shows only a few collisions, but the value of peak pounding force is substantially large, what may intensify structural damage.
Modelling of Closed Steel Supports for Underground and Mining Works
Authors: Janas Petr , Janas Karel , Koubova Lenka , Krejsa Martin
Published: September 2017

The closed steel supports of different shapes are used in mining and underground constructions. The yielding and unyielding supports are prefabricated from rolled, usually robust steel profiles. The load carrying capacity of the support is considerably influenced by the active loading and passive forces. The passive forces are induced by the interactions of support with the surrounding rock massif [1]. The user-friendly software was processed for the operational determination of load carrying capacity. The analysis has three parts: the first part consists of the structural geometry processing. The second part includes the numerical solution of statically indeterminate structure for the specified load. The third part is the calculation of load carrying capacity, components of internal forces and deformations. The force method and the numerical integration were used for solution. The Winkler model is applied when the support is in interaction with the surrounding environment. The load carrying capacity of support is limited by the slip resistance of the connected parts and reaching the ultimate state of the profile. The plasticity calculation is performed in accordance with EN 1993-1-1 Ed. 2. The limit values beyond the scope of this standard can be selected for an alternative computation.
Structural Performance of Exterior Beam-Column Joints with Large Diameter Headed Bars
Authors: Jung Hyung Suk , Choi Hyun Ki , Choi Chang Sik , Chung Joo Hong
Published: September 2017

Generally, a conventional standard hook is used for the reinforcement's anchorage. However, this results in steel congestion, and it makes fabrication and construction difficult. Using a headed bar offers a potential solution for these problems and may also ease fabrication, construction and concrete placement. But, in current design code of the headed bar, it had limitation about the yield strength and the diameter of rebar etc. It hard to use the large diameter headed bar in the reinforced concrete structure. This paper presents the cyclic responses of four reinforced concrete exterior beam-column joints, which are anchored with large diameter headed bars or hooked bars. To evaluate the anchorage capacity of large diameter headed bars, specimen variables were set with anchorage detail, side cover thickness of concrete, and transverse reinforcement. Also, structural performance of beam-column joints is evaluated and compared with each other. The behavior of joints with headed bars are as good as, or better than those companion joints with 90-degree hooked bars. Test results show that the large diameter headed bar has enough anchorage capacity in exterior beam-column joints. Test results show side cover of concrete improved the anchorage capacity of the bars and transverse reinforcement enhanced the anchorage capacity and ductility of joints.
Discrete Modeling of Strain Rate Effect in Concrete Fracture
Authors: Květoň Josef , Eliáš Jan
Published: September 2017

Concrete fracture can be simulated in static regime, however, it is a dynamical process. For very slow loading rates, the kinetic energy is negligible compared to the energy dissipated by fracturing, and the influence of inertia can be neglected. In all other cases, neglecting the influence of inertia forces can lead to improper results. With increasing loading rate, increase in strength and energy dissipation as well as changes in crack pattern can be observed. The contribution presents dynamical simulations of experiments on concrete specimens under various displacement rates, from very slow, quasi-static, to high displacement rates. The simulations are calculated using discrete particle model, the material is represented by a system of interconnected ideally rigid polyhedral particles. The solution of equations of motion is calculated using implicit time integration Newmark scheme. The constitutive behavior of the material is strain rate independent. For high strain rates the influence of inertia forces dominates and is mainly responsible for increase in loading forces as well as for change in the crack pattern and crack branching. The results obtained with the model are compared to experimental data from literature.
Degradation State Assessment of Rolling Bearing Based on Variational Mode Decomposition and Energy Distribution
Authors: Han Te , Jiang Dong Xiang , Yang Wen Guang
Published: September 2017

Degradation state assessment of bearing is an important part of prognostic and health management (PHM) in rotating machinery. Generally, the energy distribution of frequency band is sensitive to degradation state for rolling bearing. Hence, a novel assessment method based on variational mode decomposition (VMD) and energy distribution is proposed in this work. Firstly, the VMD is used to decompose raw vibration signal into several components with different scales and frequency bands. These components is capable of reflecting the local characteristic of vibration signal. Then, the energy distribution of these components is utilized as feature vector. Finally, the different bearing states can be classified by the scatter plots of the first several principal components after principal component analysis (PCA). The analysis of an experimental dataset demonstrates the effectiveness of this methods. The comparative analysis shows the VMD is superior to traditional empirical mode decomposition (EMD) methods.
Growth and Interaction of Debonds in Local Clusters of Fibers in Unidirectional Composites during Transverse Loading
Authors: Varna Janis , Zhuang Lin Qi , Pupurs Andrejs , Ayadi Zoubir
Published: September 2017

Fiber/matrix debonding in transverse tensile loading of a unidirectional composite is analyzed calculating energy release rate (ERR) for interface crack propagation. Non-uniform fiber distribution (local hexagonal fiber clustering) is assumed in the model. The matrix region containing the central fiber with the debond and the 6 surrounding fibers is embedded in a large block of homogenized composite which has the same fiber content as the region analyzed explicitly. Some of the fibers surrounding the central fiber may also have a debond. The effect of the local clustering and of the presence of other debonds on magnification of the ERR is analyzed.
Influence of the Crack Widening on the Transverse Cracking in Lamellar Metal-Ceramic Composites
Authors: Piat Romana , Kashtalyan Maria , Guz Igor
Published: September 2017

Stress field in the ceramic layer containing multiple transverse cracks is determined using a modified 2-D shear lag approach and a finite element method.
The Evaluation of Deformation and Fracture of Gilsocarbon Graphite Subject to Service Environments: Experimental and Modelling
Authors: Šavija B. , Smith G.E. , Heard P.J. , Sarakinou E. , Darnbrough J.E. , Hallam K.R. , Schlangen E. , Flewitt P.E.J.
Published: September 2017

Commercial graphites are used for a wide range of applications. For example, Gilsocarbon graphite is used within the reactor core of Advanced Gas Cooled Reactors (UK) as a moderator. In service, the mechanical properties of the graphite are changed as a result of neutron irradiation induced defects and porosity arising from radiolytic oxidation. In this paper, we discuss measurements undertaken of mechanical properties at the micro-length-scale for virgin and irradiated material. These data provide the necessary inputs to an experimentally-informed model that predicts the deformation and fracture properties of Gilsocarbon graphite at the centimetrelength-scale. The results provide an improved understanding of how the mechanical properties and fracture characteristics of this type of graphite change as a result of exposure to the service environment.
Continuum models in wealth distribution
Authors: Toscani Giuseppe
Published: September 2017

We present and discuss the main analogies between continuum mechanics and the laws of an evolving economy. A sound basis for these connections is kinetic theory, which provides both mathematical and physical arguments to build up efficient mathematical models.
Galilean invariance and entropy principle for a system of balance laws of mixture type
Authors: Arima Takashi , Ruggeri Tommaso , Sugiyama Masaru , Taniguchi Shigeru
Published: September 2017

After defining, in analogy with a mixture of continuous media, a
system of balance laws of mixture type
, we study the general properties obtained by imposing the Galilean invariance principle. For constitutive equations of local type we study also the entropy principle and we prove the compatibility between the two principles. These general results permit us to construct, from a single constituent theory, the corresponding theory of mixtures in an easy way. As an illustrative example of the general theory, we write down the hyperbolic system of balance laws of mixtures in which each component has 6 fields (mass density, velocity, temperature and dynamic pressure, among which only the last one is a nonequilibrium variable). This is the simplest system after Eulerian mixtures. Global existence of smooth solutions for small initial data is also proved.
2017 Frank Newman Speller Award: Knowledge-Based Predictive Analytics in Corrosion
Authors: Sridhar Narasi
Published: September 2017

Corrosion researchers have developed many approaches to predicting the occurrence of different corrosion modes. Four types of predictive analytics can be identified: data-centric correlative analysis, theory-based semi-empirical models, expert-knowledge-based models, and theory-based, multi-scale models. However, most new corrosion failures have been serendipitous discoveries, rather than anticipated through a systematic process. This paper reviews stress corrosion cracking (SCC) of carbon steel in non-aqueous electrolytes and in aqueous solutions of oxyanions, to understand whether using the appropriate predictive analytic strategy may have helped anticipate the failures. In all of these cases of SCC, some information was available in related environments prior to field failures, but a framework was lacking to identify the connections and anticipate failures. Data-centric predictive analytics would not have helped anticipate the failures because of the low frequency of the phenomena and the lack of prior failure data. A better predictive analytic strategy will need methods to integrate diverse sources of knowledge into a theoretical framework. Predictive analytics also must have a probabilistic component because both the knowledge and data are uncertain. The paper provides a conceptual approach to developing such a predictive analytics framework.
Crossing the Chasm: How to develop weather and climate models for next generation computers?
Authors: Lawrence Bryan N. , Rezny Michael , Budich Reinhard , Bauer Peter , Behrens Jörg , Carter Mick , Deconinck Willem , Ford Rupert , Maynard Christopher , Mullerworth Steven , Osuna Carlos , Porter Andrew , Serradell Kim , Valcke Sophie , Wedi Nils , Wilson Simon
Published: September 2017

Abstract. Weather and climate models are complex pieces of software which include many individual components, each of which is evolving under the pressure to exploit advances in computing to enhance some combination of a range of possible improvements (higher spatio/temporal resolution, increased fidelity in terms of resolved processes, more quantification of uncertainty etc). However, after many years of a relatively stable computing environment with little choice in processing architecture or programming paradigm (basically X86 processors using MPI for parallelism), the existing menu of processor choices includes significant diversity, and more is on the horizon. This computational diversity, coupled with ever increasing software complexity, leads to the very real possibility that weather and climate modelling will arrive at a chasm which will separate scientific aspiration from our ability to develop and/or rapidly adapt codes to the available hardware. In this paper we review the hardware and software trends which are leading us towards this chasm, before describing current progress in addressing some of the tools which we may be able to use to bridge the chasm. This brief introduction to current tools and plans is followed by a discussion outlining the scientific requirements for quality model codes which have satisfactory performance and portability, while simultaneously supporting productive scientific evolution. We assert that the existing method of incremental model improvements employing small steps which adjust to the changing hardware environment is likely to be inadequate for crossing the chasm between aspiration and hardware at a satisfactory pace, in part because institutions cannot have all the relevant expertise in house. Instead, we outline a methodology based on large community efforts in engineering and standardisation, one which will depend on identifying a taxonomy of key activities – perhaps based on existing efforts to develop domain specific languages, identify common patterns in weather and climate codes, and develop community approaches to commonly needed tools, libraries etc – and then collaboratively building up those key components. Such a collaborative approach will depend on institutions, projects and individuals adopting new interdependencies and ways of working.
Effect of winds and waves on salt intrusion in the Pearl River
Estuary
Authors: Gong Wenping , Lin Zhongyuan , Chen Yunzhen , Chen Zhaoyun , Zhang Heng
Published: September 2017

Abstract. Salt intrusion in the Pearl River Estuary (PRE) is a dynamic process that is influenced by a range of factors and to date, few studies have examined the effects of winds and waves on salt intrusion in the PRE. We investigate these effects using the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system applied to the PRE. After careful validation, the model is used for a series of diagnostic simulations. It is revealed that the local wind considerably strengthens the salt intrusion by lowering the water level in the eastern part of the estuary and increasing the bottom landward flow. The remote wind increases the water mixing on the continental shelf, elevates the water level on the shelf and in the PRE, and pumps saltier shelf water into the estuary by Ekman transport. Enhancement of the salt intrusion is comparable between the remote and local winds. Waves decrease the salt intrusion by increasing the water mixing. Sensitivity analysis shows that the axial down-estuary wind, is most efficient in driving increases in salt intrusion via wind straining effect.
New forms of -compactness with respect to hereditary classes
Authors: Qahis Abdo Mohammed
Published: September 2017

A hereditary class on a set X is a nonempty collection of subsets closed under heredity. The aim of this paper is to introduce and study strong forms of u-compactness in generalized topological spaces with respect to a hereditary class, called  SuH-compactness and S- SuH-compactness. Also several of their properties are presented. Finally some eects of various kinds of functions on them are studied.