(1S,2R,2′S)‐ and (1S,2S,2′S)‐1‐phenyl‐2‐phenyl­thio‐2‐(tetra­hydro­pyran‐2′‐yl­thio)­ethanol diastereoisomers at 193 K

In the synthesis of 1‐phenyl‐2‐phenyl­thio‐2‐(tetra­hydro­pyran‐2‐yl­thio)­ethanol, C₁₉H₂₂O₂S₂, four diastereoisomers are formed. Two non‐centrosymmetric enantiomeric forms which crystallize in space groups P2₁2₁2₁ and Pna2₁ are presented. The former has an intramolecular hydrogen bond between the hydroxyl group and the O atom of the tetra­hydro­pyran ring. In the latter isomer, the hydroxyl group forms an intermolecular hydrogen bond to the O atom of the tetra­hydro­pyran­yl group of a neighbouring mol­ecule, joining the mol­ecules into chains in the c‐axis direction; the O?O distances are 2.962 (4) and 2.764 (3) Å, respectively. The tetra­hydro­pyran rings are in chair conformations in both isomers and the S side chain has an equatorial orientation in the former, but an axial orientation in the latter mol­ecule.     

Scheduling the Australian Football League

Generating a schedule for a professional sports league is an extremely demanding task. Good schedules have many benefits for the league, such as higher attendance and TV viewership, lower costs and increased fairness. The Australian Football League is particularly interesting because of an unusual competition format integrating a single round-robin tournament with additional games. Furthermore, several teams have multiple home venues and some venues are shared by multiple teams. This paper presents a 3-phase process to schedule the Australian Football League. The resulting solution outperforms the official schedule with respect to minimizing and balancing travel distance and breaks, while satisfying more requirements.     

Analytical methods in DNA and protein adduct analysis

DNA or protein adducts are reaction products of endogenous or exogenous chemicals and cellular macromolecules. Adducts are useful in toxicological studies and/or human biomonitoring exercises. In particular, DNA damage provides invaluable information for risk analysis. Second, metabolites or conjugates can be regarded as markers of phase II reactions though they may not give accurate information about the levels of reactive and damage-provoking reactive compounds or intermediates. Electrophiles are often short-lived molecules and therefore difficult to monitor. In contrast, adducts are often chemically stable, though their levels in biological samples are low, which makes their detection challenging. The assay of adducts is similar to the analysis of any other trace organic molecule, i.e. problems with the matrix and small amounts of analytes in samples. The ³²P-postlabelling assay is a specific method for DNA adducts but immunochemical and fluorescence-based methods have been developed which can detect adducts linked to both DNA and protein. Tandem mass spectrometry, particularly if combined with ultrahigh-performance liquid chromatography, is currently the recommended detection technique; however investigators are striving to develop novel ways to achieve greater sensitivity. Standards are a prerequisite in adduct analysis, but unfortunately they are seldom commercially available.     

Performance of an air sampler and a gamma-ray detector in a small unmanned aerial vehicle

The performance of an air sampler and a small gamma-ray spectrometer was tested in an unmanned aerial vehicle (UAV) able to carry payload with mass up to 0.5 kg. Operation of the sampler was investigated with the aid of radon progeny normally present in outdoor air. Detection limits for several transuranium nuclides in air are of the order of 0.3 Bq m^?3 assuming 0.5 h sampling time and 1 h counting time in direct alpha spectrometry. Unshielded ¹³⁷Cs and ⁶⁰Co point sources at the ground level were used to test the CsI spectrometer. Detection limits are approximately 1 GBq or larger depending on the flying altitude.     

Securing the Communication in Private Heterogeneous Mobile Ad hoc Networks

Mobile ad hoc networking has been a hot research topic for a decade or so, and many paradigms have been making use of it. One of these paradigms is the Personal Networks (PN). It is an emerging concept where the user’s personal devices form a virtual network which is secure and private, and reacts to changing environment and context intelligently. A fundamental property of the PN is that personal devices form private multi-hop clusters in an ad hoc manner whenever they come across each other. To this end, this paper presents a pair-wise key based scheme for forming secured private clusters in mobile ad hoc networks. The solution tackles the problem of node authentication combined with traffic encryption in relatively small ad hoc networks using proactive neighbour discovery and authentication. Additionally, the paper proves the feasibility of this solution by means of prototyping and experimental performance analysis.     

B-Site Co-Alloying with Germanium Improves the Efficiency and Stability of All-Inorganic Tin-Based Perovskite Nanocrystal Solar Cells

Colloidal lead-free perovskite nanocrystals have recently received extensive attention because of their facile synthesis, the outstanding size-tunable optoelectronic properties, and less or no toxicity in their commercial applications. Tin (Sn) has so far led to the most efficient lead-free solar cells, yet showing highly unstable characteristics in ambient conditions. Here, we propose the synthesis of all-inorganic mixture Sn-Ge perovskite nanocrystals, demonstrating the role of Ge²⁺ in stabilizing Sn²⁺ cation while enhancing the optical and photophysical properties. The partial replacement of Sn atoms by Ge atoms in the nanostructures effectively fills the high density of Sn vacancies, reducing the surface traps and leading to a longer excitonic lifetime and increased photoluminescence quantum yield. The resultant Sn-Ge nanocrystals-based devices show the highest efficiency of 4.9 %, enhanced by nearly 60 % compared to that of pure Sn nanocrystals-based devices.     

Electron‐Beam Manipulation of Silicon Impurities in Single‐Walled Carbon Nanotubes

The recent discovery that impurity atoms in crystals can be manipulated with focused electron irradiation has opened novel perspectives for top‐down atomic engineering. These achievements have been enabled by advances not only in electron optics and microscope stability but also in the preparation of suitable materials with impurity elements incorporated via ion and electron‐beam irradiation or chemical means. Here it is shown that silicon heteroatoms introduced via plasma irradiation into the lattice of single‐walled carbon nanotubes (SWCNTs) can be manipulated using a focused 55–60 keV electron probe aimed at neighboring carbon sites. Moving the silicon atom mainly along the longitudinal axis of large 2.7 nm diameter tubes, more than 90 controlled lattice jumps are recorded and the relevant displacement cross sections are estimated. Molecular dynamics simulations show that even in 2 nm diameter SWCNTs, the threshold energies for out‐of‐plane dynamics are different than in graphene, and depend on the orientation of the silicon‐carbon bond with respect to the electron beam as well as the local bonding of the displaced carbon atom and its neighbors. Atomic‐level engineering of SWCNTs where the electron wave functions are more strictly confined than in 2D materials may enable the fabrication of tunable electronic resonators and other devices.     

HIBI Communication Network for System-on-Chip

This paper presents a communication network targeted for complex system-on-chip (SoC) and network-on-chip (NoC) designs. The Heterogeneous IP Block Interconnection (HIBI) aims at maximum efficiency and minimum energy per transmitted bit combined with quality-of-service (QoS) in transfers. Other features include support for hierarchical topologies with several clock domains, flexible scalability, and runtime reconfiguration of network parameters. HIBI is intended for integrating coarse-grain components such as intellectual property (IP) blocks that have size of thousands of gates.HIBI has been implemented in VHDL and SystemC and synthesized on several CMOS technologies and on FPGA. A 32-bit wrapper requires 5400 gates and runs with 315 MHz on 0.18 μ m technology which shows that only minimal area overhead is paid for the advanced features. The area and frequency results are well comparable to other NoC proposals.Furthermore, data transfers are shown to approach the maximum theoretical performance for protocol efficiency. HIBI network is accompanied with a design framework with tools for optimizing the system through automated design space exploration. Erno Salminen Tampere University of Technology (TUT), Finland.Currently he is working towards his PhD degree in the Institute of Digital and Computer Systems (DCS) at TUT. His main research interests are digital systems design and communication issues in SoCs. Tero KangasTampere University of Technology (TUT), Finland.Since 1999 he has been working as a research scientist in the Institute of Digital and Computer Systems (DCS) at TUT. Currently he is working towards his PhD degree and his main research topics are system architectures and SoC design methodologies in multimedia applications. Timo D. H?m?al?ainen Tampere University of Technology (TUT), Finland. He was nominated to full professor at TUT/Institute of Digital and Computer Systems in 2001. He heads the DACI research group that focuses on three main research areas: wireless sensor networks, high-performance multi-DSP and hardware based video encoding, and design flow tools for heterogeneous MP-SoC platforms. Jouni Riihi?mki Tampere University of Technology (TUT), Finland. Currently he is working as a senior design engineer at Nokia Technlogy Platforms. He is also working towards his PhD degree. His research interests include SoC design and verification methodologies. Vesa Lahtinen received his M.Sc. and Ph.D. from TUT in 1998 and 2004, respectively. In TUT, his main research areas were system-on-chips and their interconnects. Currently, Dr. Lahtinen is a Senior Research Engineer in the Computing Architectures Laboratory of Nokia Research Center (NRC) concentrating on architecture modeling and, specifically, memory architectures. Kimmo Kuusilinna Tampere University of Technology (TUT), Finland. His main research interests include system-level design and verification, on-chip interconnections, and parallel memories. Currently he is working as a senior research engineer at the Nokia Research Center.     

Nonlinear dynamics of three-dimensional belt drives using the finite-element method

In this paper, new nonlinear dynamic formulations for belt drives based on the three-dimensional absolute nodal coordinate formulation are developed. Two large deformation three-dimensional finite elements are used to develop two different belt-drive models that have different numbers of degrees of freedom and different modes of deformation. Both three-dimensional finite elements are based on a nonlinear elasticity theory that accounts for geometric nonlinearities due to large deformation and rotations. The first element is a thin-plate element that is based on the Kirchhoff plate assumptions and captures both membrane and bending stiffness effects. The other three-dimensional element used in this investigation is a cable element obtained from a more general three-dimensional beam element by eliminating degrees of freedom which are not significant in some cable and belt applications. Both finite elements used in this investigation allow for systematic inclusion or exclusion of the bending stiffness, thereby enabling systematic examination of the effect of bending on the nonlinear dynamics of belt drives. The finite-element formulations developed in this paper are implemented in a general purpose three-dimensional flexible multibody algorithm that allows for developing more detailed models of mechanical systems that include belt drives subject to general loading conditions, nonlinear algebraic constraints, and arbitrary large displacements. The use of the formulations developed in this investigation is demonstrated using two-roller belt-drive system. The results obtained using the two finite-element formulations are compared and the convergence of the two finite-element solutions is examined.