171,968 research outputs found
Three contra-rotating currents from a rational design of polycyclic aromatic hydrocarbons: altan-corannulene and altan-coronene
No full textBoth the ab initio expression of the current density within the ipsocentric approach and conjugated circuit models indicate that placing an unsaturated hydrocarbon inside a [4n]annulene, in such a way that outgoing C–H bonds are substituted by C–C bonds to alternating carbon atoms of the annulene, leads to an homologue altan-molecule whose perimeter is expected to preserve the paratropic circulation of the parent annulene. Computations of current on the novel altan-corannulene and altan-coronene revealed unprecedented patterns of three contra-rotating paratropic/diatropic/paratropic circulations. Graph-theoretical methods have been used to highlight the peculiar topology of these altan-molecules
Three Contra-Rotating Currents from a Rational Design of Polycyclic Aromatic Hydrocarbons: <i>altan</i>-Corannulene and <i>altan</i>-Coronene
No full textBoth the ab initio expression of the
current density within the ipsocentric approach and conjugated circuit
models indicate that placing an unsaturated hydrocarbon inside a [4n]annulene, in such a way that outgoing C–H bonds
are substituted by C–C bonds to alternating
carbon atoms of the annulene, leads to an homologue altan-molecule whose perimeter is expected to preserve the
paratropic circulation of the parent annulene. Computations of current
on the novel altan-corannulene and altan-coronene revealed unprecedented patterns of three contra-rotating
paratropic/diatropic/paratropic circulations. Graph-theoretical methods
have been used to highlight the peculiar topology of these altan-molecules
Recent Achievements in Numerical Simulation in Sheet Metal Forming Processes
No full textPurpose of this paper: During the recent 10-15 years, Computer Aided Process Planning and Die Design evolved as one of the most
important engineering tools in sheet metal forming, particularly in the automotive industry. This emerging role is strongly emphasized by
the rapid development of Finite Element Modelling, as well. The purpose of this paper is to give a general overview about the recent
achievements in this very important field of sheet metal forming and to introduce some special results in this development activity.
Design/methodology/approach: Concerning the CAE activities in sheet metal forming, there are two main approaches: one of them may
be regarded as knowledge based process planning, whilst the other as simulation based process planning. The author attempts to integrate
these two separate developments in knowledge and simulation based approach by linking commercial CAD and FEM systems.
Findings: Applying the above approach a more powerful and efficient process planning and die design solution can be achieved radically
reducing the time and cost of product development cycle and improving product quality.
Research limitations: Due to the different modelling approaches in CAD and FEM systems, the biggest challenge is to enhance the
robustness of data exchange capabilities between various systems to provide an even more streamlined information flow.
Practical implications: The proposed integrated solutions have great practical importance to improve the global competitiveness of sheet
metal forming in the very important segment of industry.
Originality/value: The concept described in this paper may have specific value both for process planning and die design engineers
Terahertz time-domain study of silver nanoparticles synthesized by laser ablation in organic liquid
No full textWe report the investigation of laser-synthesized Ag nanoparticles (Ag-NPs) in an organic liquid environment by using terahertz time-domain spectroscopy (THz-TDS) technique. Colloidal Ag-NPs with an average diameter of 10 nm in two-propanol solution through nanosecond pulsed laser ablation were synthesized. THz-TDS measurements were performed on different volumetric concentration of Ag-NPs suspensions placed in 2-mm path length quartz cuvette. Due to the dispersive and highly absorptive nature of the nano liquids, an approach based on extracting the optical properties through the changes in amplitude and phase solely around the main peak of THz waveform is developed. This approach allowed for an accurate estimation of the complex refractive index of the Metallic-NPs suspension for the different prepared volumetric concentrations. In addition, using Maxwell-Garnett theory, the NP concentration is also extracted. This method shows that the time-domain nature of the THz pulse measurement technique is extremely useful in instances where slight variations in highly dispersive samples need to be investigated
The Monasteries Of Altan Khan: Genesis Of A Distinctive Architecture For Mongolian Buddhism
No full textThis dissertation studies a distinct architectural form of the Tibetan-rite Buddhist great assembly halls associated with Altan Khan and other members of the Dayan Khanid aristocracy. Altan Khan (16 th c.) deserves credit for ending the hostile relations with Ming China—which had continued after the fall of the Great Yuan Mongol Empire—and introduced the Gelug School, a branch of Tibetan-rite Buddhism, into Mongolia. A distinguishing feature of the Altan Khan Monasteries is that their Tsogchin halls are all structured in a unified architectural form, comprising a gate tower, a Tibetan-style chanting court, and a Chinese-style Buddha hall. In this dissertation, I have termed this architectural form the “Altan Khan-style Tsogchin.” The Altan Khan-style Tsogchin is a triumphant achievement in transforming the Chinese-style architectural structure specifically for Tibetan-rite Buddhism use; and, it turned it into a distinctive architectural form, one among the earliest surviving and best-preserved timber-structures in Mongolia. Since Altan Khan Monasteries were constructed at the request of Tibetan monks, patronized by Mongol nobles, and completed by Chinese artisans, the monasteries discussed in this dissertation were founded amidst political and religious competition in the triangular relationship among the Chinese, Mongolians and Tibetans.
This dissertation examines the structural and spatial features, craftsmanship, and layout of Altan Khan-style Tsogchins and reveals the genetic threads connecting the monasteries of the Altan Khan and Dayan Khanid aristocracy. This dissertation has followed a narrative format wherein each chapter focuses on one Altan Khan Monastery and discusses a specific topic that brings us closer to understanding Altan Khan-style Tsogchins, or monasteries. The eight chapters investigate the formation, models, spatial organization, structural features, developmental stages, and achievements of the Altan Khan-style Tsogchin. The thesis concludes that the column network represents a distinctive but local structural mode which Altan Khan selected deliberately to establish his rulership and manifest the legitimacy of his governance. In addition, it also argues that other monasteries associated with Altan Khan’s relatives and allies also evince similar political motivation behind their construction beyond the structural similarities. Moreover, those monasteries presented political and religious needs in their designs and served religious, political, residential, and funerary functions. This dissertation refers to the connection as genetic.
This dissertation makes its primary arguments based on structural analysis and presents more than 100 original diagrams of building structures. At the same time, it endeavors to provide wide-ranging, additional information through which to better understand and appreciate Altan Khan and the politics of Tümed Mongols in the late-sixteenth and early-seventeenth centuries
The role of computer-aided 3D surgery and stereolithographic modelling for vector orientation in premaxillary and trans-sinusoidal maxillary distraction osteogenesis
No full textBackground Maxillary distraction osteogenesis is a challenging procedure when it is performed with internal submerged distractors due to obligation of setting accurate distraction vectors. Methods Five patients with severe maxillary retrognathy were planned with Mimics 10.01 CMF and Simplant 10.01 software. Distraction vectors and rods of distractors were arranged in 3D environment and on STL models. All patients were operated under general anaesthesia and complete Le Fort I downfracture was performed. Results All distractions were performed according to orientated vectors. All patients achieved stable occlusion and satisfactory aesthetic outcome at the end of the treatment period. Conclusion Preoperative bending of internal maxillary distractors prevents significant loss of operation time. 3D computer-aided surgical simulation and model surgery provide accurate orientation of distraction vectors for premaxillary and internal trans-sinusoidal maxillary distraction. Combination of virtual surgical simulation and stereolithographic models surgery can be validated as an effective method of preoperative planning for complicated maxillofacial surgery cases. Copyright (C) 2009 John Wiley & Sons, Ltd
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Recensione a C. Tullio-Altan, Gli italiani in Europa. Profilo storico comparato delle identità nazionali europee, Bologna, Il Mulino, 1999
No full textRecensione al volume di C.T. Altan
Integrated Process Simulation and Die Design in Sheet Metal Forming
No full textDuring the recent 10-15 years, Computer Aided Process Planning and Die Design
evolved as one of the most important engineering tools in sheet metal forming, particularly in
the automotive industry. This emerging role is strongly emphasized by the rapid development
of Finite Element Modelling, as well. The purpose of this paper is to give a general overview
about the recent achievements in this very important field of sheet metal forming and to
introduce some special results in this development activity. Therefore, in this paper, an
integrated process simulation and die design system developed at the University of Miskolc,
Department of Mechanical Engineering will be analysed. The proposed integrated solutions
have great practical importance to improve the global competitiveness of sheet metal forming
in the very important segment of industry. The concept described in this paper may have
specific value both for process planning and die design engineers
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