bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kationische stickstoffdotierte helikale Nanographene
Authors: Xu Kun , Fu Yubin , Zhou Youjia , Hennersdorf Felix , Machata Peter , Vincon Ilka , Weigand Jan J. , Popov Alexey A. , Berger Reinhard , Feng Xinliang 
Published: September 2017

AbstractWir berichten über Design und Synthese einer Serie von neuen kationischen stickstoffdotierten Nanographenen (CNDN) mit einer nichtplanaren Geometrie und axialer Chiralität. Einkristall‐Röntgendiffraktometrie beweist deren helikale und teils “Cove”‐terminierte Struktur. Verglichen mit den reinen Kohlenstoffanalogen liegen die Grenzorbitale der CNDN energetisch tiefer, was zu einer verringerten optischen Energielücke und einer erhöhten Elektronenaffinität führt. Alle Derivate zeigen in cyclovoltammetrischen Untersuchungen quasireversibles Reduktionsverhalten. Abhängig von der Zahl an Stickstoffdotanden ist es möglich, neutrale Radikale (bei einem Stickstoffdotanden) oder Radikalkationen (bei zwei Stickstoffdotanden) während des Reduktionsprozesses über In‐situ‐Spektroelektrochemie zu analysieren. Kationische Stickstoffdotierung kombiniert mit Helizität erschließt neue Wege für das Design und die Synthese von ausgedehnten Nanographenen und Nanographenstreifen.
Decentralized Sliding Mode Control for Multi‐Input Complex Interconnected Systems Subject to non‐smooth Nonlinearities
Authors: Liu Wen‐Jeng 
Published: September 2017

AbstractMany modern control systems become gradually more complicated and, consequently, the approach to control design approaches is both difficulty and complex. Moreover, if such a complex interconnected system is subjected to non‐smooth nonlinearities in the actuator, then unexpected difficulties, degradation or, even worse, instability will arise in the system performance. Therefore, a new decentralized sliding mode control (DSMC) approach for such a class of complex interconnected systems subjected to non‐smooth (deadzone) nonlinearities is proposed in this paper. Based on sliding mode control (SMC) theory, the proposed DSMC laws guarantee the global reaching condition of the sliding mode in uncertain complex interconnected systems with deadzone nonlinearities, that is, they can ensure that the sliding mode is reached in finite time and with prescribed transient behavior. In the sliding mode, the investigated uncertain complex interconnected system with deadzone nonlinearities in the actuator still are insensitive to system uncertainties and external disturbances. The proposed DSMC laws can work effectively for uncertain complex interconnected systems either with or without deadzone nonlinearities in the actuator. However, this cannot be guaranteed by the traditional DSMC design for systems without input deadzone nonlinearities. Furthermore, the sliding motion can be controlled to converge within a specified exponential speed. Finally, two illustrative examples with a series of computer simulations are presented to demonstrate the effectiveness of the proposed DSMC laws.
ZD Method Based Nonlinear and Robust Control of Agitator Tank
Authors: Zhang Yunong , Ding Yaqiong , Qiu Binbin , Wen Jianfeng , Li Xiaodong 
Published: September 2017

AbstractTo improve industrial efficiency, an agitator tank system should have not only a short response time, but also produce reagents with accurate concentration and moderate liquid level. This paper presents a new method called Zhang dynamics (ZD) to perform tracking control, that is, to make the concentration and liquid level of the agitator tank converge to the desired trajectories. Two controllers for tracking control of an agitator tank system are designed based on ZD method. In addition, the robustness of the agitator tank system equipped with ZD controllers is investigated. Theoretical analyses on the convergence performance and robustness of the agitator tank system equipped with ZD controllers are presented. To substantiate the effectiveness of the ZD method for tracking control of the agitator tank system, we perform simulations on three different groups of tracking trajectories, which reflects the corresponding application conditions in the chemical industry. To test the robustness of the agitator tank system equipped with ZD controllers, additional simulations with different disturbances added in the agitator tank system and the ZD controllers are performed. Simulation results validate the feasibility and effectiveness of the ZD method for tracking control of the agitator tank system.
Enhancing Oxygen Storage Capability and Catalytic Activity of Lanthanum Oxysulfide (La2O2S) Nanocatalysts by Sodium and Iron/Sodium Doping
Authors: Tan Shuai , Li Dongmei 
Published: September 2017

AbstractWe report the enhanced oxygen storage capability (OSC) and activity of lanthanum oxysulfide (La2O2S) nanocatalysts, derived from the introduction of oxygen vacancies by sodium (Na) doping. Additionally, iron/sodium (Fe/Na) co‐doping further increased the OSC by three times, with an additional 15–20 % increase in CO conversion for the water‐gas shift (WGS) reaction, compared with the best CO conversion rate among Na‐doped La2O2S catalysts. The significant enhancement in OSC and activity after Fe/Na co‐doping may be attributed to the presence of Fe2+↔Fe3+ redox couple. Finally, the Fe/Na co‐doped nanocatalyst alleviated the high temperature requirement of La2O2S catalysts without compromising stability.
Hydrogen/Deuterium‐Exchange Reactions of Methane with Aromatics and Cyclohexane Catalyzed by a Nanoscopic Aluminum Chlorofluoride
Authors: Calvo Beatriz , Braun Thomas , Kemnitz Erhard 
Published: September 2017

AbstractH/D‐exchange reactions between methane and deuterated solvents such as [D6]benzene and [D12]cyclohexane were heterogeneously catalyzed by nanoscopic aluminum chlorofluoride (ACF=AlClxF3−x, x≈0.05–0.3) under very mild conditions. 13C NMR spectroscopy experiments at labeled methane revealed the formation of all isotopologues. AlCl3, AlBr3, HS‐AlF3, γ‐Al2O3, and γ‐Al2O3 preheated at 700 °C did not show any H/D‐exchange reaction of methane or [D6]benzene. Mechanistically, electrophilic activation of methane was suggested at the ACF surface.
03.15: Experimental tests and model study on self‐drilling screws connections subjected to shear
Authors: Gryniewicz Marcin , Szlendak Jerzy Kazimierz 
Published: September 2017

ABSTRACTResearch on shear resistance of the steel sheeting plates with thickness from 0,50 to 1,50 mm connected by self‐drilling screws is undertaken and presented in this paper. One screw type with one diameter has been used. This kind of the single lap fastening is commonly used in a steel sheeting. Experimental and theoretical data about a connections slip and shear stiffness is a one of most important issue in case of a stressed skin diaphragm action problems. At the present practice the linear model of connections is effectively used however for more advanced analyses, the non‐linear models have to be taken into consideration. These are necessary in case of the advanced design and implementation of the stressed skin action in the steel structures covered by the corrugated metal sheeting. Such a model study is presented herein which intend to investigate the general connection behaviour where the main selected variable is the plate thickness. The test are performed according to the current standards EN 1990 and ECCS handbooks. It leads to a statistical evaluation of proposed functions for the design slip of fasteners and its limits. The theoretical basis of experimental tests under the shear load is presented.
03.17: Design of haunches in structural steel joints
Authors: Kurejková Marta , Wald František , Šabatka Lubomír , Kabeláč Jaromír 
Published: September 2017

ABSTRACTThe paper presents research into the advanced design of stiffeners in structural steel joints. Experimental results of six specimens of haunches with and without flanges are presented. Three specimens are without flanges and three specimens are supported by additional flanges. Flanges differ in stiffness to observe the increase of haunch resistances and its effect on buckling shapes.Haunches with and without flanges are validated by numerical model to tests and resistances are calculated and evaluated. The research finite element model (RFEM) is studied by material and geometrical nonlinear finite element analysis with imperfections under the actual stress conditions and validated on the measured experimental data. The quality of prediction is demonstrated on the comparison of load‐deflection curves and failure modes. The stability analysis of a joint with a haunch is used for design Component Based Finite Element Models (CBFEM) of complex joints. RFEM allows verifying the design FEM model (DFEM) and component based FEM model (CBFEM) developed for the design of complex joints in steel structures. To avoid local buckling of slender plates in CBFEM a design procedure is proposed and verified on research finite element model (RFEM). It is proposed to use a combination of material nonlinear analysis without imperfections with buckling analysis in CBFEM. The verification is shown on an example of a haunch in a welded portal frame joint. The stiffener is studied by numerical analysis, resistances and critical loads are determined in RFEM and CBFEM and results are compared. A numerical study illustrates the effect of the haunch's thickness on the joint's resistance.
03.20: Experimental tests on beam‐end connectors of cold‐formed steel storage pallet racks
Authors: Giordano Saverio , Gusella Federico , Lavacchini Giovanni , Orlando Maurizio , Spinelli Paolo 
Published: September 2017

ABSTRACTThe key role of beam‐column joints in the seismic response of moment resisting frames (MRF) has been fully recognized. In the performance‐based seismic design of steel storage pallet racks, many researches have highlighted the need to take into account the inelastic response of beam‐column joints. Pallet racks are characterized by boltless beam‐column connections and the extensive use of thin‐walled cold‐formed steel members. Due to the great number of beam‐end connector types and member geometries, specific tests are required to evaluate the structural behavior of these structures. In particular, their seismic analysis requires a thorough modeling of the behavior of beam‐column joints, which has been investigated by the authors through experimental tests under monotonic and cyclic loads. Tested connectors have exhibited different values of the bending stiffness and the ultimate bending moment, depending on structural details of each joint's type, like the number of tabs. Cyclic tests have shown a pinching in the hysteresis curve, underlining that the cyclic response of tested joints is significantly different from joints of traditional steel framed buildings. Experimental results confirmed the importance of cyclic tests on beam‐end connectors to correctly identify their moment‐rotation curve, which is required to perform reliable seismic analyses of steel pallet racks.
03.30: Connection classification for a space structure jointing system
Authors: Chenaghlou Mohammad Reza , Hamed Arash Akbari 
Published: September 2017

ABSTRACTA crucial consideration in the analysis of space structures is the decision of how the connections are to be modelled. This depends on the configuration and dimensions of the structure to be analysed as well as the material and the type of connections employed. A number of attempts for connection classification have been reported and among these two classification systems i.e. classification system in Eurocode 3 and classification system by Bjorhovde et al. have received more attention. These two classification systems have been developed for beam‐to‐column connections. In order to appraise the two classification systems for a space structure jointing system, a parametric study has been carried out on the effects of connections on compression member behaviour. Based on the obtained results, a methodology for the classification of connections in space structures has been proposed. The proposed classification method uses floating boundaries that give more flexibility to the classification.
04.03: Buckling behaviour of axially compressed cylindrical shells made of stainless steel
Authors: Gorbachov Anna , Stranghöner Natalie , Rotter J. Michael 
Published: September 2017

ABSTRACTCylindrical shells made of stainless steels are widely used, e.g. in tanks and biogas plants [1]. Whereas austenitic stainless steels were commonly used in the past, austenitic‐ferritic and lean duplex stainless steels are more frequently used nowadays. By contrast with structural steels, stainless steels exhibit a significantly nonlinear stress‐strain behaviour which must be considered in the buckling analysis of these shells because the reduced material stiffness below the proof stress may cause premature buckling. For this reason, EN 1993‐1‐6 [2] indicates the use of either a reduced value of elastic modulus Ered or the secant modulus at the 0.2% proof stress when assessing the buckling resistance of shells with nonlinear stress‐strain curves. These provisions may produce over‐conservative low buckling strengths for stainless steel shells at both low and high slendernesses. Only stainless steel shells with medium slenderness are covered by this rule.For this reason, additional temperature‐ and slenderness‐dependent buckling strength correction factors for austenitic stainless steel axially loaded cylindrical shells were developed by Hautala and Schmidt (1999) [3,4] which were described in the ECCS Design Recommendations [5] for buckling of steel shells but are not yet implemented into EN 1993‐1‐6. Recent experimental, numerical and theoretical research, carried out within the European RFCS research project BiogaSS on austenitic‐ferritic and ferritic stainless steels has investigated the potential to apply these buckling strength correction factors to austenitic‐ferritic and ferritic stainless steels. This paper shows that shells made of austenitic‐ferritic and ferritic stainless steels have a less serious deviation from the reference mild steel than austenitic stainless steel, permitting less significant buckling strength correction factors.The results obtained for all families of stainless steels should be transformed into the generalized design verification format of EN 1993‐1‐6, in which a parameterized capacity curve [6,7] is used. This paper also shows how the correction factors devised for axially loaded shells made of austenitic stainless steel can be better represented by an appropriate characterisation using the capacity curve alone. The outcome should be relevant to austenitic, austenitic‐ferritic and ferritic stainless steels when sufficient data is available. The paper also illustrates how behaviours of considerable complexity in some shell buckling situations can still be represented by the unaltered universal capacity curve [6,8].
04.05: Analysis type influence on the durability prognosis for a steel tank corroded shell
Authors: Maslak Mariusz , Pazdanowski Michal , Siudut Janusz , Tarsa Krzysztof 
Published: September 2017

ABSTRACTAn original approach to the evaluation of remaining service time of a corroded on the ground steel shell of a tank used to store liquid petroleum products is presented and discussed. A typical steel tank equipped with floating roof is analysed. The limit state for such structure is determined by the tensile hoop stress at the completely filled tank reaching the bearing capacity of steel plating. It is assumed, that in the foreseeable future the tank will not be modernized nor strengthened in any manner. The service mode of the tank will not change as well. The future progress of corrosion is forecast by the extrapolation of trends, which have appeared until now, and identified during the cyclical obligatory examinations of the tank technical condition. Detailed map of the corrosion reach and intensity determined in this way is superimposed over the numerical tank model, replicating its real imperfect geometry measured by geodetic methods. In this paper two alternative methods of analysis are compared. The first one is geometrically nonlinear (GNA), while the second one is geometrically linear (LA). The obtained results are compared with the analogous results obtained under the assumption of perfect tank geometry. It turns out that the quantitative differences with respect to the forecast tank shell life, due only to the numerical approach recommended for analysis, are substantially bigger than those generated by monotonically progressing, but locally varying corrosion progress. In the case considered in this paper, the linear analysis (LA) yields the most restrictive estimate of authoritative hoop stresses. The application of nonlinear analysis (GNA) proves to be the less restrictive approach in this field, as it takes into the account the smoothing of possible local folds in the deformed shell, and thus as a consequence making it closer to the shell with perfect geometry.
04.07: On the axial buckling of very thin‐walled cylindrical shells
Authors: Jäger‐Cañás Andreas , Pasternak Hartmut 
Published: September 2017

ABSTRACTMajor advances in the buckling analysis of cylindrical shells have been achieved in the last two decades. Eurocode nowadays provides rules for tanks up to r/t = 5000. However, since only few literature has become available in the past, dealing specifically with very thin walled shells in the range between r/t = 1500 and r/t = 10000, code provisions either are quite conservative or, in case of r/t > 5000, do barely exist. Employing modern construction methods, close‐to perfect, very thin‐walled shells can be built that are out of the scope of the design codes. Therefore, to achieve more economical designs and a better sustainability, sophisticated design tools have to be used.In this paper, modifications and extensions of the current design procedure are proposed to overcome current limitations and drawbacks. A review of experiments with a special focus on cylinders with high r/t‐ratios was conducted and modified lower bound approximation curves for the knock‐down factor α deduced. They were checked against representative experiments from literature. Test results recalculated using an axisymmetric imperfection to explore their equivalent imperfection depth, proved that even small imperfections drastically reduce the buckling strength. Using a parametric study, the result range of α was extended up to r/t = 10000. The design proposal could be approved and an equation for the determination of an equivalent imperfection depth that relates the dependence of α to the imperfection depth and the r/t‐ratio is proposed.
05.01: Lattice girders with I‐sections and slotted gusset plates: Load carrying behaviour and ultimate capacity of compression members based on full scale girder tests
Authors: Unterweger Harald , Kampleitner Andreas 
Published: September 2017

ABSTRACTNowadays trusses are often designed with I‐sections only and no direct connection between the diagonal members and the chords. For the truss joints, gusset plates – welded to the chords – are used, which are slotted for the welding connection to the diagonal member.The main focus of the paper is the specific stability behaviour of such diagonal members in compression, leading to an interaction behaviour of member buckling out of plane and local buckling of the gusset plates. Within a comprehensive study a lot of different compression members and joint configurations were studied in detail, based on nonlinear numerical analyses.The results of four full scale tests on a lattice girder are presented in detail. In the four tests different I‐sections with different gusset plate geometries were investigated. The most interesting fact is the comparison of the load carrying behaviour of the compressed diagonal members with increasing free length of the gusset plates. The member capacity of the tests is compared with the numerical results of a FE‐model, considering the measured geometric imperfections and the measured material parameters.The overall load carrying behaviour of the truss in the test is analysed and compared with simplified models for global analyses, both for the load – deformation behaviour and for the relationship between load and member axial force.Finally a simple design model for the prediction of the ultimate capacity of the compression members is presented, which consists of a buckling verification based on the equivalent member with increased buckling length (section capacity near midspan is verified) and of an additional verification of the section capacity of the gusset plate. For the latter one the interaction of local and global buckling effect is important, leading to a simplified engineering model with all the relevant sources of geometric imperfections considered. It ends up with a check of the section capacity of the gusset plate, based on 2nd order internal forces (N&M). For slender gusset plates and also diagonal members with small slenderness, the section capacity of the gusset plates limits the load carrying capacity of the member and the buckling verification of the equivalent member may be on the unsafe side.
05.04: Combined loading of slender stainless steel SHS/RHS members
Authors: Židlický Břetislav , Jandera Michal 
Published: September 2017

ABSTRACTThe presented research shows behaviour of slender stainless steel members loaded by compression and bending which is demonstrated on square and rectangular hollow sections (SHS/RHS) made of austenitic stainless steel. An initial numerical parametric study in FE software Abaqus is given and its results are compared to the existing design procedures and design standard rules. The investigated parameters are mainly the column slenderness, section slenderness, ratio between the applied bending moment and the axial compressive force. The necessity of having additional design rules for stainless steels is firstly demonstrated on the values of interaction factors ky which are significantly higher for stainless steel members due to the material non‐linearity with decreased stiffness even at lower stress levels. As an alternative, the General Method is used for comparison to the Abaqus GMNIA model results. The limitation of the method when used for members of non‐linear material behaviour is shown and a simple and safe modification of global analysis method is suggested.