bluuebunny/crossref_metadata_2025 huggingface dataset:
Possible Student Justification of Proofs
Authors: Varghese Thomas
Published: December 2011

The National Council of Teachers of Mathematics calls for an increased emphasis on proof and reasoning in school mathematics curricula. Given such an emphasis, mathematics teachers must be prepared to structure curricular experiences so that students develop an appreciation for both the value of proof and for those strategies that will assist them in developing proving skills. Such an outcome is more likely when the teacher feels secure in his/her own understanding of the concept of “mathematical proof” and understands the ways in which students progress as they take on increasingly more complex mathematical justifications. In this article, a model of mathematical proof, based on Balacheff's Taxonomy of Mathematical Proof, outlining the levels through which students might progress as they develop proving skills is discussed. Specifically, examples of the various ways in which students operating at different levels of skill sophistication could approach three different mathematical proof tasks are presented. By considering proofs under this model, teachers are apt to gain a better understanding of each student's entry skill level and so effectively guide him/her toward successively more sophisticated skill development.
The Effect of Robotics Competitions on High School Students' Attitudes Toward Science
Authors: Welch Anita , Huffman Douglas
Published: December 2011

This study was designed to examine the impact of participating in an after‐school robotics competition on high school students' attitudes toward science. Specifically, this study used the Test of Science‐Related Attitude to measure students' social implications of science, normality of scientists, attitude toward scientific inquiry, adoption of scientific attitudes, enjoyment of science lessons, leisure interest in science, and career interest in science. Results indicated that students who participated in a robotic competition had a more positive attitude toward science and science‐related areas in four of the seven categories examined: social implications of science, normality of scientists, attitude toward scientific inquiry, and adoption of scientific attitudes. Implications of results on students' attitudes are discussed.
Compressive Tests on Long Continuous Stiffened Panels
Authors: Manuel Gordo José , Guedes Soares C.
Published: December 2011

Results of eight tests on long stiffened panels under axial compression until collapse are presented. The specimens are three-bay panels with associated plates made of very high tensile steel S690. Four different configurations are considered for the stiffeners, which are made of mild or high tensile steel for bar stiffeners and mild steel for L and U shape stiffeners. The influence of the stiffener’s geometry on the ultimate strength of the stiffened panels under compression is analyzed. This series of experiments belongs to an extended series of tests that include short and intermediate panels, which allows analyzing the effect of space framing on the strength of stiffened panels.
A Passivity Based Decentralized Control Design Methodology With Application to Vehicle Dynamics Control
Authors: Villegas Carlos , Corless Martin , Griggs Wynita , Shorten Robert
Published: December 2011

A basic problem in the design of control systems is the lack of simple effective methods for designing decentralized control systems that are robust with respect to certain types of structural uncertainties. Here, we present one such design methodology that is based upon the Kalman–Yakubovich–Popov Lemma. Advantages of this approach include the ease with which output feedback controllers can be designed, and the fact that the design methodology and uncertainties are expressed using classical frequency domain notions. We use our design technique to obtain an integrated chassis controller for application to automotive dynamics.
Pole-Zero, Zero-Pole Canceling Input Shapers
Authors: Singh Tarunraj
Published: December 2011

This paper presents the development of an input-shaper/time-delay filter, which exploits knowledge of the zeros of a minimum-phase transfer function to reduce the output-transition time for a rest-to-rest maneuver problem, compared to the traditional zero vibration (ZV) input shaper. The maneuver time of the robust input shaper presented in this work will correspondingly have a smaller maneuver time compared to the zero vibration derivative (ZVD) input-shaper. The shaped profile is changing with time even after the completion of the maneuver similar to postactuation controllers. All the traditional technique for addressing multiple modes and desensitizing the filter over a specified domain of uncertainties are applicable to the technique presented in this paper.
Temperature Measurements in a Linear Generator and Marine Substation for Wave Power
Authors: Boström Cecilia , Rahm Magnus , Svensson Olle , Strömstedt Erland , Savin Andrej , Waters Rafael , Leijon Mats
Published: December 2011

This paper analyzes temperature measurements acquired in the offshore operation of a wave energy converter array. The three directly driven wave energy converters have linear generators and are connected to a marine substation placed on the seabed. The highly irregular individual linear generator voltages are rectified and added on a common dc-link and inverted to 50 Hz to facilitate future grid-connection. The electrical power is transmitted to shore and converted to heat in a measuring station. The first results of temperature measurements on substation components and on the stator of one of the linear generators are presented based on operation in linear and in nonlinear damping. The results indicate that there might be some convective heat transfer in the substation vessel. If high power levels are extracted from the waves, this has to be considered when placing components in the substation vessel in order to avoid heating from neighboring components. The results also indicate that the temperature increase in the linear generator stator is very small. Failure due to excessive heating of the stator winding polyvinyl chloride cable insulation is unlikely to occur even in very energetic sea states. Should this conclusion be incorrect, the thermal conductivity between the stator and the hull of the wave energy converter could be enhanced. Another suggested alteration is to lower the resistive losses by reducing the linear generator current density.
A Method for Analyzing Elastic Large Deflection Behavior of Perfect and Imperfect Plates With Partially Rotation-Restrained Edges
Authors: Kee Paik Jeom , Kyun Kim Do , Lee Hoseong , Lae Shim Yong
Published: December 2011

The edge condition of the plating in a continuous stiffened-plate structure is neither simply supported nor clamped because the torsional rigidity of the support members at the plate edges is neither zero nor infinite. In a robust ship structural design, it is necessary to accurately take into account the effect of the edge condition in analyses of plate behavior in terms of buckling and post-buckling behavior. The aim of this study is to develop a new method for analyzing the geometric nonlinear behavior (i.e., elastic large deflection or post-buckling behavior) of plates with partially rotation-restrained edges in association with the torsional rigidity of the support members and under biaxial compression. An analytical method was developed to solve this problem using the nonlinear governing differential equations of plates. The validity of the developed method was confirmed by comparison with nonlinear finite element method solutions with varying values for the torsional rigidity of the support members, plate aspect ratio, and biaxial loading ratio. The developed method was found to give reasonably accurate results for practical design purpose in terms of the large deflection analysis of plates with partially rotation-restrained edges, and it will be useful for the robust design of ship structures in association with buckling and ultimate strength of plates surrounded by support members.
A Nonlinear Clutch Pressure Observer for Automatic Transmission: Considering Drive-Shaft Compliance
Authors: Gao Bingzhao , Chen Hong , Tian Lu , Sanada Kazushi
Published: December 2011

For a new kind of automatic transmissions adopting clutch-to-clutch shift control technology, a clutch pressure observer is proposed to improve the estimation accuracy during the shift torque phase. The observer is designed in the concept of input-to-state stability. Lookup tables, which are widely used to represent the complex nonlinear characteristics of engine systems, appear in their original form in the designed reduced-order observer, and the torsional stiffness of the drive axle shaft is considered in the model-based design procedure to improve the estimation accuracy. Finally, the designed pressure observer is tested on an amesim powertrain simulation model. Comparisons with an observer without considering the drive shaft compliance are given as well.
Adaptive and Efficient Ammonia Storage Distribution Control for a Two-Catalyst Selective Catalytic Reduction System
Authors: Hsieh Ming-Feng , Wang Junmin
Published: December 2011

This paper presents an adaptive urea-SCR dosing control design for a two-catalyst SCR system. A novel SCR ammonia storage distribution control (ASDC) approach aiming to simultaneously increase the SCR NOx conversion efficiency and reduce the tailpipe ammonia slip was proposed and experimentally validated. Based on the insight into SCR operational principles, a high ammonia storage level at the upstream part of the catalyst can generally yield a higher NOx reduction efficiency while a low ammonia storage level at the downstream part of the catalyst can reduce the undesired tailpipe ammonia slip. To achieve such an ammonia storage distribution control, a two-catalyst (in series) SCR system with NOx and NH3 sensors was devised. Grounded in a newly developed SCR control-oriented model, an adaptive (with respect to the SCR ammonia storage capacity) controller was designed to control the urea injection rate for achieving different ammonia storages in the two catalysts. Experimental data from a US06 test cycle conducted on a medium-duty Diesel engine system showed that, with the similar total engine-out NOx emissions and NH3 (AdBlue) consumptions, the proposed ASDC strategy simultaneously reduced the tailpipe NOx emissions by 57% and the ammonia slip by 74% in comparison to those from a conventional controller.
Cathode encapsulation of organic light emitting diodes by atomic layer deposited Al2O3 films and Al2O3/a-SiNx:H stacks
Authors: Keuning W. , van de Weijer P. , Lifka H. , Kessels W. M. M. , Creatore M.
Published: December 2011

Al2O3 thin films synthesized by plasma-enhanced atomic layer deposition (ALD) at room temperature (25 °C) have been tested as water vapor permeation barriers for organic light emitting diode devices. Silicon nitride films (a-SiNx:H) deposited by plasma-enhanced chemical vapor deposition served as reference and were used to develop Al2O3/a-SiNx:H stacks. On the basis of Ca test measurements, a very low intrinsic water vapor transmission rate of ≤ 2 × 10−6 g m−2 day−1 and 4 × 10−6 g m−2 day−1 (20 oC/50% relative humidity) were found for 20–40 nm Al2O3 and 300 nm a-SiNx:H films, respectively. The cathode particle coverage was a factor of 4 better for the Al2O3 films compared to the a-SiNx:H films and an average of 0.12 defects per cm2 was obtained for a stack consisting of three barrier layers (Al2O3/a-SiNx:H/Al2O3).
Monolithic integration of silicon CMOS and GaN transistors in a current mirror circuit
Authors: Hoke W. E. , Chelakara R. V. , Bettencourt J. P. , Kazior T. E. , LaRoche J. R. , Kennedy T. D. , Mosca J. J. , Torabi A. , Kerr A. J. , Lee H.-S. , Palacios T.
Published: December 2011

GaN high electron mobility transistors (HEMTs) were monolithically integrated with silicon CMOS to create a functional current mirror circuit. The integrated circuit was fabricated on 100 mm diameter modified silicon-on-insulator (SOI) wafers incorporating a resistive (111) silicon handle substrate and a lightly doped (100) silicon device layer. In a CMOS-first process, the CMOS was fabricated using the (100) device layer. Subsequently GaN was grown by plasma molecular beam epitaxy in windows on the (111) handle substrate surface without wire growth despite using gallium-rich growth conditions. Transmission lines fabricated on the GaN buffer/SOI wafer exhibited a microwave loss of less than 0.2 dB/mm up to 35 GHz. Direct current measurements on GaN HEMTs yielded a current density of 1.0 A/mm and transconductance of 270 mS/mm. At 10 GHz and a drain bias of 28 V, 1.25 mm long transistors demonstrated a small signal gain of 10.7 dB and a maximum power added efficiency of 53% with a concomitant power of 5.6 W. The silicon and GaN transistors were interconnected to form high yield test interconnect daisy chains and a monolithic current mirror circuit. The CMOS output drain current controlled the GaN transistor quiescent current and consequently the microwave gain.
InGaN laser diodes operating at 450–460 nm grown by rf-plasma MBE
Authors: Skierbiszewski C. , Siekacz M. , Turski H. , Muzioł G. , Sawicka M. , Feduniewicz-Żmuda A. , Smalc-Koziorowska J. , Perlin P. , Grzanka S. , Wasilewski Z. R. , Kucharski R. , Porowski S.
Published: December 2011

This work demonstrates the first true blue laser diodes (LDs) grown by plasma assisted molecular beam epitaxy that operate at the region of 450–460 nm. The single quantum well LDs were grown on several types of c-plane bulk GaN substrates, with threading dislocation densities varying from 104 to 108cm−2. The key factors that allowed the authors to achieve lasing in true-blue wavelengths are improvements in the growth technology of the InGaN quantum wells attributed to the high nitrogen flux used and the design of the LD structure, which reduced the light losses in the cavity. The authors discuss the influence of the diodes’ design on the parameters of LDs.
Effect of annealing on interfacial and band alignment characteristics of HfO2/SiO2 gate stacks on Ge substrates
Authors: Li Xue-Fei , Liu Xiao-Jie , Fu Ying-Ying , Li Ai-Dong , Zhang Wen-Qi , Li Hui , Wu Di
Published: December 2011

The authors have investigated the effect of 500 °C annealing for 60 s in N2 on interfacial and band alignment characteristics of HfO2/SiO2 gate stacks on n-type Ge substrates. X-ray photoelectron spectroscopy analyses reveal that the SiO2 interlayer can effectively suppress Ge outdiffusion during HfO2 growth and subsequent postdeposition annealing process. The electrical measurement shows that capacitance equivalent thickness of 1.75 nm and a leakage current density of 3.9 × 10−3 A/cm2 at gate bias of flatband voltage (Vfb) + 1 V was obtained for the annealed sample. The conduction band offsets at the HfO2/SiO2/Ge with and without annealing are found to be 2.22 and 2.07 eV, respectively.
Nanoscratch testing of atomic layer deposition and magnetron sputtered TiO2 and Al2O3 coatings on polymeric substrates
Authors: Kääriäinen Tommi O. , Kelly Peter J. , Cameron David C. , Beake Ben , Li Heqing , Barker Clara M. , Struller Carolin F.
Published: December 2011

Titania and alumina thin films are commercially important materials, finding a wide variety of applications. These materials are commonly deposited onto glass substrates by reactive magnetron sputtering techniques, or more recently by atomic layer deposition (ALD). Such films have been well-characterized in terms of their structures and properties, including their nanomechnical and nanotribological properties. There is increasing demand, though, to deposit thin (<100 nm) functional films onto polymeric substrates, which can provide cost and weight savings and opens up the potential of deposition in large throughput roll-to-roll coating systems. However, polymeric substrates impose severe limitations due to both their thermal and mechanical properties. In the former case, production is restricted to low temperature processes and in the latter case, the substrate offers negligible load support for the thin ceramic coating. While nanoindentation and nanotribological testing of thin ceramic coatings on rigid substrates have become established techniques, the same cannot be said of testing similar “hard” coatings on “soft” flexible polymeric substrates. It is recognized that the coating/substrate system is very different in nature and the mechanisms of failure may also be very different. Sub-100 nm titania and alumina coatings have, therefore, been deposited onto a range of polymeric substrate materials by low temperature ALD and, for comparison purposes, magnetron sputtering techniques, including mid-frequency pulsed dc and high power impulse magnetron sputtering. Nanoscratch testing has been carried out on these coatings usingspherical indenters. Indenter radius and loading rate were varied and their influence on the elastoplastic properties of the film and the substrate are considered and comparisons are made withthesame coating materials deposited onto “rigid” substrates.
SPATIALLY FLAT FRW MODELS WITH A NONMINIMALLY COUPLED GHOST SCALAR FIELD AND PERFECT FLUID IN EINSTEIN–CARTAN THEORY
Authors: GALIAKHMETOV A. M.
Published: December 2011

Exact general solutions to the Einstein–Cartan equations are obtained for spatially flat Friedmann cosmologies with a nonminimally coupled ghost scalar field and perfect fluid. It is shown that both singular and bouncing models are possible. An analogous problem is investigated in general relativity. Some effects of torsion are elucidated. The role of perfect fluid in the Einstein–Cartan cosmology is discussed.
Chemical Composition and Thermal Stability of Atomic Force Microscope-Assisted Anodic Oxides as Nanomasks for Molecular Beam Epitaxy
Authors: Cha Kyu Man , Shibata Kenji , Kamiko Masao , Yamamoto Ryoichi , Hirakawa Kazuhiko
Published: December 2011

We have investigated the thermal stability of GaAs-oxides grown by atomic force microscope (AFM)-assisted anodic oxidation to identify the conditions suitable for fabricating oxide nanomasks for molecular beam epitaxy (MBE). The oxides grown at bias voltages, V
ox, less than 30 V were desorbed after standard thermal cleaning in MBE, while the oxide patterns fabricated at V
ox ≥40 V survived on the GaAs surfaces. From X-ray photoemission spectroscopy, we have found that the better thermal stability of AFM-oxides grown at V
ox > 40 V can be attributed to the formation of Ga2O3 and that Ga2O3 can be used as nanomasks for site-controlled MBE growth.
Dielectric and Piezoelectric Properties of (K0.48Na0.52)(Nb0.98Sb0.02)O3–BiScO3 Lead-Free Ceramics
Authors: Wang Mingsong , Zhu Jiliang , Liu Jing , Zhu Bo , Li Xuhai , Sun Ping , Zhu Xiaohong , Zhu Jianguo , Xiao Dingquan
Published: December 2011

Lead-free ceramics (1-x)(K0.48Na0.52)(Nb0.98Sb0.02)O3–xBiScO3 + 0.8 mol % MnCO3 have been fabricated by conventional sintering technique. The results of X-ray diffraction suggest that all samples show pure perovskite structure and the structure changes from orthorhombic to tetragonal with the increase of BiScO3. At room temperature, the polymorphic phase transition (PPT) from orthorhombic to tetragonal phases was identified. With the increase in BiScO3 content, both the cubic–tetragonal and tetragonal–orthorhombic phase transitions shift to lower temperatures; hence, the dielectric and piezoelectric properties are significantly enhanced. As a result, the ceramic with x=0.015 exhibits the following optimum properties: d
33=265 pC/N, k
p=0.509, k
t=0.503, εr =1409, tan
δ=0.034.
Low-Loss Amorphous Silicon Multilayer Waveguides Vertically Stacked on Silicon-on-Insulator Substrate
Authors: Kang JoonHyun , Atsumi Yuki , Oda Manabu , Amemiya Tomohiro , Nishiyama Nobuhiko , Arai Shigehisa
Published: December 2011

Low-loss amorphous-silicon (a-Si) waveguides comprising three vertically stacked layers prepared on silicon-on-insulator substrates are demonstrated. We have fabricated multilayer a-Si waveguides and investigated their loss characteristics; this is the first such investigation to our knowledge. All the process temperatures were regulated below 400 °C for the complementary metal oxide semiconductor (CMOS) backend process compatibility. When the surface roughness and sidewall roughness were decreased, the propagation loss decreased to 3.7 dB/cm even in the case of the third layer a-Si waveguide. Such low-loss waveguides can be effectively applied to realize multilayer stacked optical devices.
Structural Study of BF2 Ion Implantation and Post Annealing of BaSi2 Epitaxial Films
Authors: Hara Kosuke O. , Usami Noritaka , Hoshi Yusuke , Shiraki Yasuhiro , Suzuno Mitsushi , Toko Kaoru , Suemasu Takashi
Published: December 2011

We have investigated the effects of BF2 ion implantation and subsequent annealing on the structure of epitaxial BaSi2 thin films with the aim of the fabrication of a p-type B-doped BaSi2 film. After 10 min of annealing at 600 °C and above, BaSi2 is lost at least partly accompanied by appearance of Si as evidenced by X-ray diffraction and Raman spectroscopy. Element mapping by energy dispersive X-ray spectroscopy revealed that a barium oxide is formed on the surface, which indicates that BaSi2 is oxidized into a barium oxide and Si during annealing. Such oxidation was found to be suppressed by employing rapid thermal annealing for 30 s even when the annealing temperatures of 700 and 800 °C were chosen. Analysis of the full width at half maximum of the Raman peak showed that the inhomogeneous stress in the film produced by ion implantation can be decreased to the as-grown level by rapid thermal annealing at 700 and 800 °C for 30 s. At the same time, the red shift of the Raman peak is shown, based on which the possibility of B substitution for Si is discussed.
Study on Occupation Behavior of Y2O3 in X8R Nonreducible BaTiO3-Based Dielectric Ceramics
Authors: Yao Guofeng , Wang Xiaohui , Li Longtu
Published: December 2011

The effects of Y2O3 on BaTiO3–MgO–MnO2–CaZrO3 nonreducible ceramics were investigated. Specimens with Y2O3 contents ranging from 1.0 to 2.5 mol % were prepared via the solid state method. The Curie temperature (T
c) and the electrical properties were closely related to the occupation behavior of yttrium, which is known as an amphoteric element. T
c increased almost linearly as a function of Y2O3 content when the doping content was low. Transmission electron microscopy (TEM) indicated a typical “core–shell” structure. The lattice parameters corresponding to the grain cores and the shells were determined by X-ray diffractometry (XRD) separately. The relief of the internal stresses arising from the lattice mismatch was responsible for the T
c shift. The specimens doped by a high level of Y2O3 can fulfill the EIA X8R specification with a high dielectric constant (εRT > 2400) and a low dielectric loss (tan
δ< 1.1%). A high insulation resistivity and a slow degradation rate were obtained when a sufficient amount of Y2O3 was incorporated, which were attributed to the substitution of Ti4+ and the formation of a donor–acceptor complex.
Large Tunnel Magnetoresistance of Full-Heusler CoFeAlSi Alloy Granular Films
Authors: Kondo Michiaki , Chino Takuro , Fujiwara Yuji , Jimbo Mutsuko
Published: December 2011

The tunnel magnetoresistance (TMR) and the structure of full-Heusler CoFeAlSi (CFAS)–Al2O3 granular films have been investigated. It was found that the most part of the film was in discontinuous layers after annealing at 673 K. A maximum MR ratio of about 18% was obtained at room temperature under a magnetic field of 8 kOe. The X-ray diffraction pattern of the film exhibited a weak peak of CFAS(220) and/or MgO(200) at about 45°, and a halo-like pattern with two peaks within the range 20–30°. These results suggest that the high MR ratio observed is related to the existence of granules with high spin polarization.
Simultaneous Measurement of Electron and Ion Transfer in All-Solid Ion-Transfer Device Made of Transition Metal Cyanide Films
Authors: Shibata Takayuki , Kamioka Hayato , Moritomo Yutaka
Published: December 2011

Simultaneous measurements of electron and ion transfers were performed in an all solid ion-transfer device made of transition metal cyanide films, indium–tin oxide (ITO)/Na
x
Ni[Fe(CN)6]0.68·5.1H2O (NNF68)/Na
x
Co[Fe(CN)6]0.90·2.9H2O (NCF90)/ITO, against time (t) and temperature (T). At 330 K, the current density (I) steeply decreases below 10 s, and then becomes nearly constant above 10 s. We found that there exists time-lag between the electron and ion transfers. We analyzed the I–t curves with an equivalent circuit, which consists of the external component (R
ex) of resistance, the bulk component (R') resistance, the leak current component (R
leak), and the capacitance (C). The large R' component was ascribed to suppressed current density owning to the local charge neutrality.
Dependence of Electrical Characteristics on the Depth of the Recess Region in the Scaled Tantalum Nitride–Aluminum Oxide–Silicon Nitride–Silicon Oxide–Silicon Flash Memory Devices
Authors: Jang Sang Hyun , Jin Jun , Kim Kyoung Won , Kim Hyun Woo , You Joo Hyung , Lee Keun Woo , Kim Tae Whan
Published: December 2011

Nanoscale tantalum nitride–aluminum oxide–silicon nitride–silicon oxide–silicon (TANOS) memory devices utilizing a recess region were investigated to improve device performance and reduce cell-to-cell interference. The dependence of electrical properties on the depth of the recess region in the TANOS flash memory devices was simulated by using Synopsys TCAD Sentaurus. The cell-to-cell interference characteristics of the TANOS flash memory devices dependent on the recess region were investigated. The drain current at an on-state in the TANOS flash memory devices increased with increasing depth of the recess region owing to the existence of the fringe field generated from the recess region. The coupling ratio of the TANOS flash memory increased with increasing depth of the recess region. The simulation results showed that the cell-to-cell interference in the TANOS flash memory devices decreased with increasing depth of the recess region.
Enhanced Light Output Power of GaN Light-Emitting Diodes with Graphene Film as a Transparent Conducting Electrode
Authors: Seo Tae Hoon , Oh Tae Su , Chae Seung Jin , Park Ah Hyun , Lee Kang Jea , Lee Young Hee , Suh Eun-Kyung
Published: December 2011

We report the enhanced light output power of GaN-based light-emitting diode (LED) by using graphene film as a transparent conducting electrode. Monolayer graphene was synthesized on copper foil by using chemical vapor deposition method and directly transferred onto the GaN-LED as a top electrode. Compared to the conventional LEDs using indium tin oxide (ITO) layer for an electrode material, the light output power of LED with graphene electrode was improved by ∼25%. This was attributed excellent graphene characteristics of high electrical conductivity, high optical transmittance of nearly 97% over a wide range of infrared, visible, and ultraviolet region and large area uniformity with fewer defects.
Two-Step Growth of (0001) ZnO Single-Crystal Layers on (0001) Sapphire Substrates by Halide Vapor Phase Epitaxy
Authors: Masuda Rui , Togashi Rie , Murakami Hisashi , Kumagai Yoshinao , Koukitu Akinori
Published: December 2011

The heteroepitaxial growth of (0001) ZnO on (0001) sapphire substrates by halide vapor phase epitaxy using a two-step growth procedure was investigated. X-ray diffraction analysis revealed that single-crystal (0001) ZnO layers on (0001) sapphire substrates were grown at 400 °C. High-temperature heteroepitaxy at 1000 °C on (0001) sapphire substrates was realized by two-step growth using the ZnO layer grown at 400 °C as a buffer layer. Two-dimensional layer growth at 1000 °C was realized on buffer layers thicker than 0.4 µm. Photoluminescence (PL) measurements performed at room temperature for the ZnO layer grown on the 0.4-µm-thick buffer layer showed a significant blueshift of near-band-edge emission (NBE). A thick buffer layer of 0.8 µm was found to be necessary for a successful two-step growth without a blueshift of NBE in the PL spectra, which is caused by a large compressive stress.
Multiattribute Response of Maize Genotypes Tested in Different Coastal Regions of Brazil
Authors: Araújo Lúcio Borges de , Varela Nualles Mario , Araújo Mirian Fernandes Carvalho , Dias Carlos Tadeu dos Santos
Published: December 2011

This work applies the three mode principal components analysis to analyze simultaneously the multiple attributes; to fit of models with additive main effects and multiplicative interaction effects (AMMI models) and the regressions models on sites (SREG models); to evaluate, respectively, the multivariate response of the genotype × environment interaction and the mean response of 36 genotypes of corn tested in 4 locations in Brazil. The results were presented by joint plots to identify the best genotypes for their adaptability and performance in the set of attributes.
Slicing Cuts on Food Materials Using Robotic‐Controlled Razor Blade
Authors: Zhou Debao , McMurray Gary
Published: December 2011

Cutting operations using blades can arise in a number of industries, for example, food processing industry, in which cheese, fruit and vegetable, even meat, are involved. Certain questions will rise during these works, such as “why pressing‐and‐slicing cuts use less force than pressing‐only cuts” and “how is the influence of the blade cutting‐edge on force”. To answer these questions, this research developed a mathematical expression of the cutting stress tensor. Based on the analysis of the stress tensor on the contact surface, the influence of the blade edge‐shape and slicing angle on the resultant cutting force were formulated and discussed. These formulations were further verified using experimental results by robotic cutting of potatoes. Through studying the change of the cutting force, the optimal slicing angle can be obtained in terms of maximum feeding distance and minimum cutting force. Based on the blade sharpness properties and the specific materials, the required cutting force can be predicted. These formulation and experimental results explained the basic theory of blade cutting fracture and further provided the support to optimize the cutting mechanism design and to develop the force control algorithms for the automation of blade cutting operations.
Internally Controlled, Generic Real-Time PCR for Quantification and Multiplex Real-Time PCR with Serotype-Specific Probes for Serotyping of Dengue Virus Infections
Authors: Menting Sandra , Thai Khoa T. D. , Nga Tran T. T. , Phuong Hoang L. , Klatser Paul , Wolthers Katja C. , Binh Tran Q. , de Vries Peter J. , Beld Marcel
Published: December 2011

Dengue has become a global public health problem and a sensitive diagnostic test for early phase detection can be life saving. An internally controlled, generic real-time PCR was developed and validated by testing serial dilutions of a DENV positive control RNA in the presence of a fixed amount of IC with results showing a good linearity (R2=0.9967) and a LOD of at least1.95×104 copies/mL. Application of the generic PCR on 136 patient samples revealed a sensitivity of 95.8% and specificity of 100%. A newly developed multiplex real-time PCR with serotype-specific probes allowed the serotyping of DENV for 80 out of 92 (87%) generic real-time PCR positive patients. Combined these real-time PCRs offer a convenient diagnostic tool for the sensitive and specific quantification of DENV in clinical specimens with the possibility for serotyping.
Phenomenology of Graphite Burning in Air Ingress Accidents of HTRs
Authors: Moormann Rainer
Published: December 2011

Air ingress with graphite burning belongs to the accident scenarios in HTRs with potentially severe consequences. This paper gives an overview of basic phenomena of graphite burning like ignition conditions and moving reaction fronts. The pioneering graphite burning experiments of Don Schweitzer are successfully reevaluated. Ignition conditions are examined, and it is underlined that burning depends not only on graphite properties but also on the heat balance in the whole graphite arrangement. In graphite‐moderated reactors, ignition occurs at about 650°C for small air flow rates: this means that normal operation temperatures in HTRs always allow for ignition. Fuel behaviour in air ingress, as determined in the KORA facility, is discussed: up to about 1300°C modern TRISO fuel is stable in air, but from 1500°C a complete, fast destruction is observed. Exemplary calculations on massive air ingress by chimney draught performed with REACT/THERMIX are outlined. For a hot bottom reflector there is a substantial time span before fuel is attacked. Because severe air ingress in well‐designed HTRs belongs to beyond design basis accidents, the knowledge is fairly good. Concerning protecting measures, a more detailed examination of thick SiC layers is proposed.
Conformational Analysis in Solution of a Chiral BisoxazolineMolecule: Vibrational Circular Dichroism Spectroscopy and DensityFunctional Theory Study
Authors: Aamouche A. , Stephens P. J.
Published: December 2011

The conformations of the chiral bisoxazoline: 2,2′‐methylenebis[3a,8a‐dihydro‐8H‐indeno[1,2‐d]oxazole] (also named IndaBOX), have been studied. Density functional theory (DFT) calculations identify four inequivalent stable conformations. Two, I and II have, C2 symmetry; two, III and IV, have C1 symmetry. The electronic energies of I–IV are ordered: I < II < III < IV. The span in energy is <1.0 kcal/mole. Vibrational unpolarised absorption and circular dichroism spectra have been predicted for the four conformations using DFT. Comparison of population‐weighted spectra to experimental spectra of CHCl3 and CDCl3 solutions in mid‐IR region strongly supports the DFT predictions of the number, structures, and relative energies of the conformations of IndaBOX. This shows that DFT predicts spectra with a high degree of reliability. We will undoubtedly illustrate the advantage added by vibrational circular dichroism spectroscopy in conformational analysis and in the absolute configuration determination.
Constructing a Distributed AUV Network for Underwater Plume-Tracking Operations
Authors: Petillo Stephanie , Schmidt Henrik , Balasuriya Arjuna
Published: December 2011

In recent years, there has been significant concern about the impacts of offshore oil spill plumes and harmful algal blooms on the coastal ocean environment and biology, as well as on the human populations adjacent to these coastal regions. Thus, it has become increasingly important to determine the 3D extent of these ocean features (“plumes”) and how they evolve over time. The ocean environment is largely inaccessible to sensing directly by humans, motivating the need for robots to intelligently sense the ocean for us. In this paper, we propose the use of an autonomous underwater vehicle (AUV) network to track and predict plume shape and motion, discussing solutions to the challenges of spatiotemporal data aliasing (coverage versus resolution), underwater communication, AUV autonomy, data fusion, and coordination of multiple AUVs. A plume simulation is also developed here as the first step toward implementing behaviors for autonomous, adaptive plume tracking with AUVs, modeling a plume as a sum of Fourier orders and examining the resulting errors. This is then extended to include plume forecasting based on time variations, and future improvements and implementation are discussed.
Adaptive and Innate Immune Responsiveness toBorrelia burgdorferi sensu latoin Exposed Asymptomatic Children and Children with Previous Clinical Lyme Borreliosis
Authors: Skogman Barbro H. , Hellberg Sandra , Ekerfelt Christina , Jenmalm Maria C. , Forsberg Pia , Ludvigsson Johnny , Bergström Sven , Ernerudh Jan
Published: December 2011

Why some individuals develop clinical manifestations in Lyme borreliosis (LB) while others remain asymptomatic is largely unknown. Therefore, we wanted to investigate adaptive and innate immune responsiveness toBorrelia burgdorferi sensu latoin exposedBorrelia-antibody-positive asymptomatic children (n=20), children with previous clinical LB (n=24), and controls (n=20). Blood samples were analyzed forBorrelia-specific interferon (IFN)-γ, interleukin (IL)-4, and IL-17 secretion by ELISPOT andBorrelia-induced IL-1β, IL-6, IL-10, IL-12(p70), and tumor necrosis factor (TNF) secretion by Luminex. We found no significant differences in cytokine secretion between groups, but a tendency towards an increased spontaneous secretion of IL-6 was found among children with previous clinical LB. In conclusion, the adaptive or innate immune responsiveness toBorrelia burgdorferi sensu latowas similar inBorrelia-exposed asymptomatic children and children with previous clinical LB. Thus, the immunological mechanisms of importance for eradicating the spirochete effectively without developing clinical manifestations of LB remain unknown.
New Formulations of Local Anaesthetics—Part I
Authors: Shipton Edward A.
Published: December 2011

Part 1 comments on the types of local anaesthetics (LAs); it provides a better understanding of the mechanisms of action of LAs, and their pharmacokinetics and toxicity. It reviews the newer LAs such as levobupivacaine, ropivacaine, and articaine, and examines the newer structurally different LAs. The addition of adjuvants such as adrenaline, bicarbonate, clonidine, and corticosteroids is explored. Comment is made on the delivery of topical LAs via bioadhesive plasters and gels and controlled-release local anaesthetic matrices. Encapulation matrices such as liposomes, microemulsions, microspheres and nanospheres, hydrogels and liquid polymers are discussed as well. New innovations pertaining to LA formulations have indeed led to prolonged action and to novel delivery approaches.
Upper Extremity Motor Learning among Individuals with Parkinson's Disease: A Meta-Analysis Evaluating Movement Time in Simple Tasks
Authors: Felix K. , Gain K. , Paiva E. , Whitney K. , Jenkins M. E. , Spaulding S. J.
Published: December 2011

Motor learning has been found to occur in the rehabilitation of individuals with Parkinson's disease (PD). Through repetitive structured practice of motor tasks, individuals show improved performance, confirming that motor learning has probably taken place. Although a number of studies have been completed evaluating motor learning in people with PD, the sample sizes were small and the improvements were variable. The purpose of this meta-analysis was to determine the ability of people with PD to learn motor tasks. Studies which measured movement time in upper extremity reaching tasks and met the inclusion criteria were included in the analysis. Results of the meta-analysis indicated that people with PD and neurologically healthy controls both demonstrated motor learning, characterized by a decrease in movement time during upper extremity movements. Movement time improvements were greater in the control group than in individuals with PD. These results support the findings that the practice of upper extremity reaching tasks is beneficial in reducing movement time in persons with PD and has important implications for rehabilitation.
Local People Attitudes towards Community Forestry Practices: A Case Study of Kosti Province-Central Sudan
Authors: Kobbail Amani Abdel Rahim
Published: December 2011

This paper examines the attitudes of local communities toward community forestry programmes implemented by a project under the CF approach in Kosti area, based on a survey of 100 people living there. The household was the basic unit of data collection; ten villages were selected as study localities. Ten respondents from each village were randomly chosen for the interview. Frequency distribution results showed that almost all the respondents have a particularly favourable perception of the community forestry programmes implemented and they perceive the best type of management for running these forests which is to be owned and managed by them. They participated in different programe activities and willing to further participation in tree planting activities. Women have possessed positive attitudes towards community forestry although they were not fully involved in community forestry Practices. Stepwise multiple linear regression analysis showed a statistical significant relation between some selected variables (Respondents age, educational level, main occupation, respondents indigenous knowledge, family uses of different forestry products, awareness of causes of forest destruction and finally respondents awareness of environmental problems) exerted important influences on the attitudes and participation of respondents. This study suggests that the project and the forest services should continue addressing local development needs, encourage women's participation in community forestry, and work toward dispute settlement of community forest-user groups, if it wants to win the support of local communities for long-term environmental conservation goals.
Why Do Young People Start Drinking? Motives for First-Time Alcohol Consumption and Links to Risky Drinking in Early Adolescence
Authors: Kuntsche Emmanuel , Müller Stefanie
Published: December 2011

Aims: To investigate which motives young adolescents indicate for first-time alcohol consumption and whether these motives are linked to risky drinking. Methods: Logistic regressions were used based on a nationally representative sample of 1,654 11- to 14-year-olds who had consumed alcohol at least once. Results: ‘To toast’ (42.5%), ‘to find out what effect it would have’ (36.4%), and ‘to have more fun at a party’ (31.0%) were most frequently indicated as motives. Boys indicated curiosity about the effect more often than girls who instead more frequently indicated coping motives. Those who had their first drink ‘to have more fun at a party’ or ‘because it was exciting’ had a higher likelihood of risky drinking. Moreover, those who indicated depression as a motive were three times more likely to have 5 or more drinks on a single occasion. Conclusions: Information on young people’s motives for first-time drinking appears to play a significant role in primary prevention, e.g. to prevent risky drinking or alcohol-related problems later in life by postponing alcohol use.
Surgical and Chemotherapeutic Options for Urachal Carcinoma: Report of Ten Cases and Literature Review
Authors: Yazawa Satoshi , Kikuchi Eiji , Takeda Toshikazu , Matsumoto Kazuhiro , Miyajima Akira , Nakagawa Ken , Oya Mototsugu
Published: December 2011

Objective: Several studies have associated urachal carcinoma with a poor prognosis, because the disease tends to be detected later as the patient is asymptomatic, there are few therapeutic options, and it has a high local recurrence rate. We review our experience with urachal carcinoma and discuss the role of surgical management and chemotherapeutic options. Patients and Methods: We reviewed the records of 10 cases with urachal carcinoma evaluated at Keio University Hospital from 1998 to 2009, and examine the surgical and chemotherapeutic options in the management of urachal carcinoma. Results: Median age was 55.0 years. Applying the TNM staging system, 1 case was in stage I, 4 cases in stage II, 4 cases in stage III, and 1 case was in stage IV. Nine cases were managed initially with surgery; 5 by partial cystectomy and 4 by total cystectomy. The median follow-up period was 3.5 years and the survival rate at 2 years was 87.5%. Six of the resected cases remain disease-free. Salvage chemotherapy was performed in 3 cases, and adjuvant chemotherapy was performed in 2 cases. Conclusions: We had 10 cases with urachal carcinoma. While there is still no standard chemotherapy combination, CPT-11 plus TS-1 produced stable disease in 1 case.
Towards a Bourgeois Revolution? Explaining the American Civil War
Authors: Ashworth John
Published: December 2011

Abstract

This paper introduces arguments from Slavery, Capitalism, and Politics in the Antebellum Republic1 to suggest that the Civil War arose ultimately because of class-conflict between on the one hand, Southern slaves and their masters and, on the other, Northern workers and their employers. It does not, however, suggest that either in the North or the South these conflicts were on the point of erupting into revolution. On the contrary, they were relatively easily containable. However, harmony within each section (North and South) could be secured only at the cost of intersectional conflict, conflict which would finally erupt into civil war. The Civil War was a ‘bourgeois revolution’ not only because it destroyed slavery, an essentially precapitalist system of production, in the United States but also because it resulted in the enthronement of Northern values, with the normalisation of wage-labour at their core.
Karl Marx and Abraham Lincoln: A Curious Convergence
Authors: Blackburn Robin
Published: December 2011

Abstract

Karl Marx and Abraham Lincoln held very different views on the ‘social question’. This essay explores the way in which they converged in their estimation of slavery during the course of the Civil War; Marx was an ardent abolitionist, and Lincoln came to see this position as necessary. It is argued that the rôle of runaway slaves – called ‘contraband’ – and German-revolutionary ’48ers played a significant rôle in the radicalisation of Lincoln and the direction of the War.
Marx and Engels on the US Civil War: The ‘Materialist Conception of History’ in Action
Authors: Nimtz August H.
Published: December 2011

Abstract

Marx’s analysis, supplemented by that of Engels, of the US Civil War is as instructive, if not more, as any of their writings to illustrate their ‘materialist conception of history’. Because the American experience figured significantly in the young Marx’s path to communist conclusions, the outbreak of the War in 1861 obligated him to devote his full attention to its course. His application of their method allowed him to see more accurately the course of the War than his partner. Also, he was able to see what President Abraham Lincoln had to do, that is, to convert the War from one to end secession to one to overthrow slavery, before the President himself. Despite its contradictory outcome, Marx’s expectation that the War would put the US working class on terra firma for the first time was justified.
Social-Property Relations, Class-Conflict and the Origins of the US Civil War: Towards a New Social Interpretation
Authors: Post Charles
Published: December 2011

Abstract

The origins of the US Civil War have long been a central topic of debate among historians, both Marxist and non-Marxist. John Ashworth’s Slavery, Capitalism, and Politics in the Antebellum Republic is a major Marxian contribution to a social interpretation of the US Civil War. However, Ashworth’s claim that the War was the result of sharpening political and ideological – but not social and economic – contradictions and conflicts between slavery and capitalism rests on problematic claims about the rôle of slave-resistance in the dynamics of plantation-slavery, the attitude of Northern manufacturers, artisans, professionals and farmers toward wage-labour, and economic restructuring in the 1840s and 1850s. An alternative social explanation of the US Civil War, rooted in an analysis of the specific path to capitalist social-property relations in the US, locates the War in the growing contradiction between the social requirements of the expanded reproduction of slavery and capitalism in the two decades before the War.
Karl Marx and Contemporary Philosophy, edited by Andrew Chitty and Martin McIvor, Basingstoke: Palgrave Macmillan, 2009
Authors: Noonan Jeff
Published: December 2011

Abstract

This essay is a review ofKarl Marx and Contemporary Philosophy. While the text will provide even knowledgeable Marxist readers with new insights on key texts and concepts in Marx, it nevertheless fails to intervene in crucial contemporary philosophical debates. The book is concerned less with the contemporary significance of Marxist philosophyas philosophyand more with re-reading classical Marxist texts in a contemporary context. This job it does well, but leaves the more important question of what Marxists have to say about fundamental philosophical problems today unaddressed for the most part.