bluuebunny/crossref_metadata_2025 huggingface dataset:
Can computational approaches aid in untangling the inherent complexity of practical organic photovoltaic systems?
Authors: Sumpter Bobby G. , Meunier Vincent
Published: April 2012

Organic materials, in particular conjugated polymers, have recently become the subject of extensive research for photovoltaic device applications. This increase of interest is primarily the result of their potentially low manufacturing cost, compatibility with flexible substrates, diverse chemical tunability, scalability, and ease of processing currently available for suitable bulk heterojunction (BHJ) construction. However, to date, these materials have not been able to exceed power conversion efficiencies (PCE) beyond 5–9%, values short of those considered commercially viable. The deficit in PCE appears to derive from a combination of physicochemical and device complexities associated with inadequate hole transport mobility, solubility and miscibility with an appropriate acceptor, narrow electronic band gap for efficient solar light harvesting, appropriate highest occupied molecular orbital (HOMO) and lowest unoccopied molecular orbital (LUMO) energies to maximize the open‐circuit voltage (Voc) and electron transfer to the acceptor, and in particular the control of the multidimensional problem of BHJ morphology. In this review article, we provide an overview of some of the recent progress toward implementing theory, modeling, and simulation approaches in combination with results from precision synthesis, characterization, and device fabrication as a mean to overcome/understand the inherent issues that limit practical applications of organic photovoltaics. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Optimization as a reasoning strategy for dealing with socioscientific decision‐making situations
Authors: Papadouris Nicos
Published: April 2012

This paper reports on an attempt to help 12‐year‐old students develop a specific optimization strategy for selecting among possible solutions in socioscientific decision‐making situations. We have developed teaching and learning materials for elaborating this strategy, and we have implemented them in two intact classes (N = 48). Prior to and after the implementation, which lasted for nine 80‐minute sessions, we collected data through a number of open‐ended tasks that asked students either to address certain decision‐making situations or to evaluate given decisions. Twenty students (42%) also participated in follow‐up interviews. Data analysis revealed that this type of intervention may lead to an improvement in students' decision‐making reasoning strategies, starting from an early stage. Specifically, after the implementation (i) most students spontaneously selected to apply the targeted optimization strategy and provided appropriate justifications for their decisions, (ii) there was a substantial reduction in the frequency of responses that either relied on noncompensatory approaches or synthesized the available information in a nonvalid manner, and (iii) there was an improvement in students' ability to elaborate reasoning flaws in given decision‐making approaches. In addition, the findings provide insights into certain challenges and confounding factors involved in designing learning materials for promoting such reasoning strategies. © 2012 Wiley Periodicals, Inc. Sci Ed 96:600–630, 2012
O2+ probe‐sample conditions for ultra low energy SIMS depth profiling of nanometre scale Si0.4Ge0.6/Ge quantum wells
Authors: Morris R. J. H. , Dowsett M. G. , Beanland R. , Dobbie A. , Myronov M. , Leadley D. R.
Published: April 2012

The O2+ probe‐sample conditions and subsequent data analysis required to obtain high depth resolution SIMS depth profiles from Si1−xGex/Ge quantum well structures (0.6 ≤ x ≤ 1) are presented. For primary beam energies Ep >500 eV and x approaching 1, a significant decrease in the Ge+ ionisation probability resulted in unrepresentative and unquantifiable depth profiles. For Ep ≤ 500 eV, a monotonic increase in the Ge+ signal with x was observed resulting in profiles representative of the sample structure and enabling x to be found. A depth scale was also established using a point‐by‐point approach taking into account the local erosion rate, which is a function of x. Both the composition and the thickness of the Si1−xGex and Ge layers were found to be in excellent agreement with those obtained using X‐ray and transmission electron microscopy. Copyright © 2012 John Wiley & Sons, Ltd.
A study on the formation mechanism of ytterbium silicide for Schottky contact applications
Authors: Na Sekwon , Choi Hwayoul , Lee Byunghoon , Choi Juyun , Seo Yujin , Kim Hyoungsub , Lee Seok‐Hee , Lee Hoo‐Jeong
Published: April 2012

This article reports some new details of the Yb silicide formation mechanism. The combination of high‐resolution transmission electron microscopy and energy dispersive spectroscopy helped us to unravel several interesting aspects of the silicidation process at the early stage. Interdiffusion between Si and Yb was extensive even at low temperatures (<250 °C) and led to the formation of an amorphous layer, followed by the nucleation of crystalline YbSi2−x at the bottom of the amorphous layer. Upon annealing at 350 °C, the silicide layer grew thicker as a flat layer of a uniform thickness with two epitaxial relations with the underlying Si lattice. Annealing at higher temperatures (400 °C and 500 °C) prompted silicide grains with random orientations to nucleate and grow on the epitaxial layer, producing a bilayer morphology. Copyright © 2012 John Wiley & Sons, Ltd.
Electron‐irradiation‐induced phase change in nanometer‐sized Al2Au particles
Authors: Lee Jung‐Goo , Mori Hirotaro
Published: April 2012

Electron irradiation effect on nanometer‐sized Al2Au compound particles has been studied by using transmission electron microscopy. Particles of Al2Au compound smaller than about 10 nm in diameter were irradiated with 200‐keV electrons at room temperature. Selective sputtering of Au atoms from Al2Au compound particles was so strong that particles of Al2Au with the CaF2 structure changed into particles of α‐Al with the fcc structure. The same irradiation experiment was also carried out using nanometer‐sized particles of AlAu with the B2 structure. However, no change in the AlAu particles could be observed after irradiation. It was revealed that the selective sputtering of Au atoms from the Al2Au compound particles under irradiation with 200‐keV electrons can be attributed to both the unique CaF2‐ type structure and the size effect of particles. Copyright © 2012 John Wiley & Sons, Ltd.
Characteristics of positive and negative secondary ions emitted from Au3+ and Au400+4 impacts
Authors: DeBord J. D. , Fernandez‐Lima F. A. , Verkhoturov S. V. , Schweikert E. A. , Della‐Negra S.
Published: April 2012

The current limitation for SIMS analyses is insufficient secondary ion yields, due in part to the inefficiency of traditional primary ions. Massive gold clusters are shown to be a route to significant gains in secondary ion yields relative to other commonly used projectiles. At an impact energy of 520 keV, Au400+4 is capable of generating an average of greater than ten secondary ions per projectile, with some impact events generating >100 secondary ions. The capability of this projectile for signal enhancement is further displayed through the observation of up to seven deprotonated molecular ions from a single impact on a neat target of the model pentapeptide leu‐enkephalin. Positive and negative spectra of leu‐enkephalin reveal two distinct emission regimes responsible for the emission of either intact molecular ions with low internal energies or small fragment species. The internal energy distribution for this projectile is measured using a series of benzylpyridinium salts and compared with the small polyatomic projectile Au3+ at 110 keV as well as distributions previously reported for electrospray ionization and fast atom bombardment. These results show that Au400+4 offers high secondary ion yields not only for small fragment ions, e.g. CN–, typically observed in SIMS analyses, but also for characteristic molecular ions. For the leu‐enkephalin example, the yields for each of these species are greater than unity. Copyright © 2012 John Wiley & Sons, Ltd.
Simple and Universal Platform for Logic Gate Operations Based on Molecular Beacon Probes
Authors: Park Ki Soo , Seo Myung Wan , Jung Cheulhee , Lee Joon Young , Park Hyun Gyu
Published: April 2012

A new platform technology is herein described with which to construct molecular logic gates by employing the hairpin‐structured molecular beacon probe as a basic work unit. In this logic gate operation system, single‐stranded DNA is used as the input to induce a conformational change in a molecular beacon probe through a sequence‐specific interaction. The fluorescent signal resulting from the opening of the molecular beacon probe is then used as the output readout. Importantly, because the logic gates are based on DNA, thus permitting input/output homogeneity to be preserved, their wiring into multi‐level circuits can be achieved by combining separately operated logic gates or by designing the DNA output of one gate as the input to the other. With this novel strategy, a complete set of two‐input logic gates is successfully constructed at the molecular level, including OR, AND, XOR, INHIBIT, NOR, NAND, XNOR, and IMPLICATION. The logic gates developed herein can be reversibly operated to perform the set‐reset function by applying an additional input or a removal strand. Together, these results introduce a new platform technology for logic gate operation that enables the higher‐order circuits required for complex communication between various computational elements.
Real‐Time Microscopy of Graphene Growth on Epitaxial Metal Films: Role of Template Thickness and Strain
Authors: Sutter Peter , Ciobanu Cristian V. , Sutter Eli
Published: April 2012

Epitaxial transition metal films have recently been introduced as substrates for the scalable synthesis of transferable graphene. Here, real‐time microscopy is used to study graphene growth on epitaxial Ru films on sapphire. At high temperatures, high‐quality graphene grows in macroscopic (>100 μm) domains to full surface coverage. Graphene nucleation and growth characteristics on thin (100 nm) Ru films are consistent with a pure surface chemical vapor deposition process, without detectable contributions from C segregation. Experiments on thicker (1 μm) films show a systematic suppression of the C uptake into the metal to levels substantially below those expected from bulk C solubility data, consistent with a strain‐induced reduction of the C solubility due to gas bubbles acting as stressors in the epitaxial Ru films. The results identify two powerful approaches—i) limiting the template thickness and ii) tuning the interstitial C solubility via strain—for controlling graphene growth on metals with high C solubility, such as Ru, Pt, Rh, Co, and Ni.
On the Cyclic Softening Mechanisms of Reduced Activity Ferritic/Martensitic Steels
Authors: Giordana Maria Florencia , Alvarez‐Armas Iris , Armas Alberto
Published: April 2012

Low‐cycle fatigue tests were performed in three different ferrite/martensite steels, i.e., the European RAFM steel EUROFER 97 and the commercials AISI 410 and AISI 420, at room temperature (RT) and at 550°C. After the first few cycles, a cyclic softening that continues up to failure is observed for all these steels. The cyclic softening exhibited by AISI 420 is less pronounced than for the other two steels. The comparison between the mechanical responses of the materials was based on the study of the flow stress components, i.e., the friction and the back stresses, and their correlation with the microstructure evolution. In most cases, the strong cyclic softening observed is produced by the decreasing stress values exhibited by both stress components. However, at RT, for AISI 420, the back stress does not present variation during cycling. The decrease of the free dislocation density inside the subgrains and the growth of the mean subgrain size represent the main microstructural evolution.
Development of an Evidence‐Based Information Booklet to Support Parents of Children Without a Diagnosis
Authors: Lewis Celine , Skirton Heather , Jones Ray
Published: April 2012

The aim of this study was to develop an evidence‐based psychosocial information booklet for parents of children without a specific diagnosis, many of whom are seen through the genetic clinic. A mixed methods approach was adopted involving four phases. The first two phases involving a systematic review and in‐depth interviews are summarised briefly but reported in detail elsewhere. Phase 3 comprised: (1) a grey literature search to identify relevant literature and resources from other patient organizations; (2) drafting the booklet using themes identified through the previous phases; (3) piloting the booklet with eight professional and support group stakeholders and (4) piloting the booklet with 14 parents (from Phase 2) to ensure the information reflected their experiences. In Phase 4, we assessed satisfaction with the booklet through a questionnaire completed by 38 parents. The booklet was well accepted. The importance of providing the booklet at the beginning of the parental ‘journey’ was identified. We have developed an evidence‐based information booklet to support parents via a rigorous mixed methods approach. This booklet meets a largely unmet psychosocial need and could be used in practice to support parents of children without a diagnosis.
Confidence Bounds and Power for the Reliability of Observational Measures on the Quality of a Social Setting
Authors: Shin Yongyun , Raudenbush Stephen W.
Published: April 2012

Social scientists are frequently interested in assessing the qualities of social settings such as classrooms, schools, neighborhoods, or day care centers. The most common procedure requires observers to rate social interactions within these settings on multiple items and then to combine the item responses to obtain a summary measure of setting quality. A key aspect of the quality of such a summary measure is its reliability. In this paper we derive a confidence interval for reliability, a test for the hypothesis that the reliability meets a minimum standard, and the power of this test against alternative hypotheses. Next, we consider the problem of using data from a preliminary field study of the measurement procedure to inform the design of a later study that will test substantive hypotheses about the correlates of setting quality. The preliminary study is typically called the “generalizability study” or “G study” while the later, substantive study is called the “decision study” or “D study.” We show how to use data from the G study to estimate reliability, a confidence interval for the reliability, and the power of tests for the reliability of measurement produced under alternative designs for the D study. We conclude with a discussion of sample size requirements for G studies.
Esterification of Free Fatty Acids in Zanthoxylum bungeanum Seed Oil for Biodiesel Production by Stannic Chloride
Authors: Zhang Junhua , Liu Jianjun , Ma Hunian
Published: April 2012

In this study, SnCl4 was chosen as a solid catalyst for esterification of free fatty acids (FFA) in Zanthoxylum bungeanum seed oil (ZSO). A central composite rotatable design was used to investigate the effect of the methanol‐to‐oil molar ratio, catalyst amount and reaction time on the SnCl4‐catalyzed esterification of FFA. The methanol‐to‐oil molar ratio and reaction time clearly affected the conversion efficiency of FFA in the test ranges. Response surface methodology was used to optimize the conditions for SnCl4‐catalyzed esterification. A quadratic polynomial equation was obtained for conversion efficiency of FFA by multiple regression analysis and verification experiments confirmed the validity of the predicted model. Under the optimum conditions, the conversion efficiency of FFA in vegetable oil reached above 96 %. This study demonstrates the effectiveness of SnCl4 as an acid catalyst for the reduction of high FFA content in vegetable oils to a low level by one‐step esterification.
Evaluation of Siberian Apricot (Prunus sibirica L.) Germplasm Variability for Biodiesel Properties
Authors: Wang Libing
Published: April 2012

The potential for using Siberian apricot (Prunus sibirica L.) seed kernel oil as a source of biodiesel raw material is often overlooked when considering Siberian apricots as a greening tree in China. The aim of this research was to study and compare the oil content and fatty acid composition of 17 germplasm accessions in northern regions of China. Oil content ranged from 44.73 to 57.83 % with a mean of 50.18 % for the 17 accessions. In AS‐080, AS‐013, AS‐017 and AS‐027, oil contents were higher than 55 %. Percentages of fatty acids varied greatly among different accessions, but all the accessions contained high amounts of important oleic acid. The biodiesel properties of the Siberian apricot seed kernels oil methyl ester were determined and compared to the relevant specifications from the ASTM D6751‐2003, EN 14214‐2005 and GB/T 20828‐2007. In general, germplasm accession PS‐80 has been identified as the ideal feedstock for biodiesel production while germplasm accessions PS‐17 and PS‐27 were found to be the promising feedstock for biodiesel production.
Using Marine Snails to Teach Biogeography and Macroevolution: The Role of Larvae and Dispersal Ability in the Evolution and Persistence of Species
Authors: Hendricks Jonathan R.
Published: April 2012

While some marine animals are capable of traveling great distances, many have limited mobility as adults and spend the majority of their lifetimes in a small geographical area or may even be cemented to a single place. While it might be expected that species with limited mobility would have small geographic distributions, some nevertheless occur over very large areas. This is the case for some marine snails (gastropods). A key factor that impacts the geographic distribution of marine snails is the type of larvae they have during the phase of their life history that follows hatching from an egg. Because adult snails do not typically travel vast distances, the mobility of the larval stage determines the species’ ability to reach new territories. Some larvae are capable of long-distance travel, while others are not. An important component of the process of speciation involves geographic isolation, so the type of larvae a snail species possesses impacts the likelihood that it will become geographically isolated and give rise to a new species. Larval form also affects how long snail species will persist on geological timescales before going extinct, as well as rates of speciation. This paper briefly reviews the evolutionary consequences of different types of larval development in marine gastropods (especially cone snails, which are one of the most diverse groups of marine animals), particularly in determining the dispersal ability and geographic ranges of individual species, the amount of genetic exchange among populations within species, and the duration of species through time. The goal of this short review is to provide context and examples for classroom discussions of the connections between biogeography and macroevolution. Furthermore, a classroom activity is presented that involves students’ using information about snail life history and biogeography to develop research plans (and predicted results) that could be utilized to test (i.e., support or reject) several macroevolutionary hypotheses.
Knockdown of von Hippel–Lindau protein decreases lung cancer cell proliferation and colonization
Authors: Zhou Qiyuan , Chen Tianji , Ibe Joyce Christina F. , Usha Raj J. , Zhou Guofei
Published: April 2012

Although von Hippel–Lindau protein (pVHL) is known as a tumor suppressor in kidney and other organs, it remains unclear whether pVHL plays a role in lung cancer development. We investigated the role of pVHL in lung cancer cell proliferation, migration, and colonization using stable A549 cells with knockdown of pVHL. We found that knockdown of pVHL promotes epithelial‐mesenchymal transition (EMT) in lung cancer cells. Knockdown of pVHL decreased tumor colonization in a tail‐vein injection model and decreased cell proliferation, whereas overexpression of constitutive active HIF increased tumor colonization, suggesting a HIF‐independent function of pVHL in lung. Knockdown of pVHL decreased phosphorylation of FAK and expression of integrin, suggesting that pVHL regulates lung cancer development via integrin/FAK signaling pathway.
Early Paleozoic magmatism in the Bumbat-Hairhan area of the Lake Zone in western Mongolia (geological, petrochemical, and geochronological data)
Authors: Rudnev S.N. , Izokh A.E. , Borisenko A.S. , Shelepaev R.A. , Orihashi Y. , Lobanov K.V. , Vishnevsky A.V.
Published: April 2012

We consider the structure, composition, and age of Early Paleozoic intrusive associations of the Bumbat-Hairhan area located in the central part of the island-arc system of the Lake Zone, western Mongolia. There are large polychronous plutons (Bumbat-Hairhan and Gundguzin) and small intrusions in this area. We have established that they are composed of granitoid and gabbroid associations of different lithology, ages, and geodynamic nature. The results of U-Pb dating show that granitoid and basic magmatism took place within 551–465 Ma. Two main stages of intrusive magmatism are recognized, which reflect two stages of the geodynamic evolution of the region: island-arc (551–524 Ma) and accretion–collision (511–465 Ma). At all stages, predominant rocks in the region were diorite–tonalite–plagiogranite and plagiogranite associations of calc-alkaline series.
Anaxagoras' Theory of Matter—I
Authors: Cornford F. M.
Published: April 2012

Anaxagoras’ theory of matter offers a problem which, in bald outline, may be stated as follows. The theory rests on two propositions which seem flatly to contradict one another. One is the principle of Homoeomereity: A natural substance such as a piece of gold, consists solely of parts which are like the whole and like one another—every one of them gold and nothing else. The other is: ‘There is a portion of everything in everything’, understood to mean that a piece of gold (or any other substance), so far from containing nothing but gold, contains portions of every other substance in the world. Unless Anaxagoras was extremely muddleheaded, he cannot have propounded a theory which simply consists of this contradiction. One or the other proposition must be reinterpreted so as to bring them into harmony. Some critics attack one, some the other; some try to modify both. Mr. C. Bailey has recently published a fresh attempt to reconstruct the theory in a form consistent with itself. But the result, as he admits, is arbitrary and (above all) uneconomical. These defects, like all the contradictions and obscurities found in other accounts of the system, can be traced to the second proposition: ‘There is a portion of everything in everything’, or rather to the construction put upon it. The language is crude, vague, and ambiguous. What does ‘everything’ mean? Has the first ‘everything’ the same sense as the second ? If taken to mean that there is a portion of every material substance in every material substance, the proposition leads to a result for which ‘uneconomical’ is an indulgent epithet.
Spectral analysis of integro-differential operators applied in linear antenna modelling
Authors: Bekers Dave J. , van Eijndhoven Stephanus J. L.
Published: April 2012

The current on a linear strip or wire solves an equation governed by a linear integro-differential operator that is the composition of the Helmholtz operator and an integral operator with a logarithmically singular displacement kernel. Investigating the spectral behaviour of this classical operator, we first consider the composition of the second-order differentiation operator and the integral operator with logarithmic displacement kernel. Employing methods of an earlier work by J. B. Reade, in particular the Weyl–Courant minimax principle and properties of the Chebyshev polynomials of the first and second kind, we derive index-dependent bounds for the ordered sequence of eigenvalues of this operator and specify their ranges of validity. Additionally, we derive bounds for the eigenvalues of the integral operator with logarithmic kernel. With slight modification our result extends to kernels that are the sum of the logarithmic displacement kernel and a real displacement kernel whose second derivative is square integrable. Employing this extension, we derive bounds for the eigenvalues of the integro-differential operator of a linear strip with the complex kernel replaced by its real part. Finally, for specific geometry and frequency settings, we present numerical results for the eigenvalues of the considered operators using Ritz's methods with respect to finite bases.
Spectrality of self-affine measures on the three-dimensional Sierpinski gasket
Authors: Li Jian-Lin
Published: April 2012

The self-affine measure μM, D corresponding to M = diag[p1, p2, p3] (pj ∈ ℤ \ {0, ± 1}, j = 1, 2, 3) and D = {0, e1, e2, e3} in the space ℝ3 is supported on the three-dimensional Sierpinski gasket T(M, D), where e1, e2, e3 are the standard basis of unit column vectors in ℝ3. We shall determine the spectrality and non-spectrality of μM, D, and show that if pj ∈ 2ℤ \ {0, 2} for j = 1, 2, 3, then μM, D is a spectral measure, and if pj ∈ (2ℤ + 1) \ {±1} for j = 1, 2, 3, then μM, D is a non-spectral measure and there exist at most 4 mutually orthogonal exponential functions in L2(μM, D), where the number 4 is the best possible. This generalizes the known results on the spectrality of self-affine measures.
A New Method to Estimate Risk and Return of Nontraded Assets from Cash Flows: The Case of Private Equity Funds
Authors: Driessen Joost , Lin Tse-Chun , Phalippou Ludovic
Published: April 2012

We develop a new methodology to estimate abnormal performance and risk exposure of nontraded assets from cash flows. Our methodology extends the standard internal rate of return approach to a dynamic setting. The small-sample properties are validated using a simulation study. We apply the method to a sample of 958 private equity funds. For venture capital funds, we find a high market beta and underperformance before and after fees. For buyout funds, we find a relatively low market beta and no evidence for outperformance. We find that self-reported net asset values significantly overstate fund values for mature and inactive funds.
Contesting discourses of blood in the ‘red shirts’ protests in Bangkok
Authors: Cohen Erik
Published: April 2012

The spilling of blood in modern political protest is an exceptional event. This article discusses the deployment of blood as a means of struggle by the members of an extra-parliamentary movement, known as the ‘red shirts’, in March 2010, in the course of their prolonged attempt to topple the government of the Thai prime minister Abhisit Vejjajiva. Two contesting discourses of blood are discussed: the symbolic discourse of blood as a self-sacrificial act deployed by the protesters to curse their enemies, and the medical counter-discourse deployed by the authorities, in an effort to neutralise the protesters' act. Several issues raised by the blood-spilling act are examined: its perceived appropriateness, its ritual roots and its disputed effectiveness as a curse. In conclusion, it is suggested that the blood ritual constitutes a reflective move to counter the prevailing ‘regime of images’ in Thai society.
Australia, the ‘Marshall experiment’ and the decolonisation of Singapore, 1955–56
Authors: Benvenuti Andrea
Published: April 2012

As decolonisation gathered pace in Southeast Asia, Singapore became a source of considerable concern to the Robert Menzies government. Britain's hold on its colony appeared increasingly precarious as political turbulence gripped the island. With a predominantly Chinese population, Singapore was considered susceptible to communist China's propaganda and subversion. By relying on previously classified Australian and British diplomatic documents, this article sheds light on the Australian approach to Singapore's political and constitutional development between 1955 and 1956 and, in so doing, it hopes to make a contribution to a better understanding of Australia's policies in a rapidly decolonising Southeast Asia.
Elite intercommunal bargaining and conflict resolution: The role of the Communities Liaison Committee in Malaya, 1949–51
Authors: Fernando Joseph M.
Published: April 2012

Between 1949 and 1951, the Communities Liaison Committee (CLC), an unofficial body comprising leaders from the main Malayan ethnic communities, served as a prototype for elite intercommunal conflict resolution during a very challenging period amid an ongoing communist insurgency. Drawing upon previously inaccessible primary sources, this article reassesses the CLC's work towards resolving divisive issues such as Malay economic backwardness, federal citizenship, national identity, education and language in Malaya. This article argues that the CLC played a significantly bigger role than previously recognised and influenced government policy considerably. Equally importantly, it entrenched the concept of consociationalism, which was to shape the Malayan political landscape long thereafter.
Position-singularity analysis of a special class of the Stewart parallel mechanisms with two dissimilar semi-symmetrical hexagons
Authors: Li Baokun , Cao Yi , Zhang Qiuju , Huang Zhen
Published: April 2012

In this paper, for a special class of the Stewart parallel mechanism, whose moving platform and base one are two dissimilar semi-symmetrical hexagons, the position-singularity of the mechanism for a constant-orientation is analyzed systematically. The force Jacobian matrix [J]T is constructed based on the principle of static equilibrium and the screw theory. After expanding the determinant of the simplified matrix [D], whose rank is the same as the rank of the matrix [J]T, a cubic symbolic expression that represents the 3D position-singularity locus of the mechanism for a constant-orientation is derived and graphically represented. Further research shows that the 3D position-singularity surface is extremely complicated, and the geometric characteristics of the position-singularity locus lying in a general oblique plane are very difficult to be identified. However, the position-singularity locus lying in the series of characteristic planes, where the moving platform coincides, are all quadratic curves compromised of infinite many sets of hyperbolas, four pairs of intersecting lines and a parabola. For some special orientations, the quadratic curve can degenerate into two lines or even one line, all of which are parallel to the ridgeline. Two theorems are presented and proved for the first time when the geometric characteristics of the position-singularity curves in the characteristic plane are analyzed. Moreover, the kinematic property of the position-singularity curves is obtained using the Grassmann line geometry and the screw theory. The theoretical results are demonstrated with several numeric examples.
Robot force control without dynamic model: theory and experiments
Authors: Rivera-Dueñas Juan C. , Arteaga-Pérez Marco A.
Published: April 2012

Among the many challenges to deal with, when a robot is interacting with its environment, friction at the contact surface and/or at the joints is one of the most important to be considered. In this paper we propose a control algorithm for the tracking of position and force (unconstrained orientation case only) of a manipulator end-effector that does not require the robot model for implementation. This characteristic has the advantage of making it capable to compensate friction effects without any previous estimation. Furthermore, no velocity measurements are needed, and the unit quaternion is employed for orientation control. Experimental and simulation results are provided.
On the terminology and geometric aspects of redundant parallel manipulators
Authors: Müller Andreas
Published: April 2012

Parallel kinematics machines (PKMs) can exhibit kinematics as well as actuation redundancy. While the meaning of kinematic redundancy has been already clarified for serial manipulators, actuation redundancy, which is only possible in PKMs, is differently classified in the literature. In this paper a consistent terminology for general redundant PKM is proposed. A kinematic model is introduced with the configuration space (c-space) as central part. The notion of kinematic redundancy is recalled for PKM. C-space, output, and input singularities are distinguished. The significance of the c-space geometry is emphasized, and it is pointed out geometrically that input singularities can be avoided by redundant actuation schemes. In order to distinguish different actuation schemes of PKM, a nonlinear control system is introduced whose dynamics evolves on c-space. The degree of actuation (DOA) is introduced as the number of independent control vector fields, and PKMs are classified as full-actuated and underactuated machines. Relating this DOA to degree of freedom allows to classify the actuation redundancy.
Entangled Stories: The Red Jews in Premodern Yiddish and German Apocalyptic Lore
Authors: Voß Rebekka
Published: April 2012

“Far, far away from our areas, somewhere beyond the Mountains of Darkness, on the other side of the Sambatyon River…there lives a nation known as the Red Jews.” The Red Jews are best known from classic Yiddish writing, most notably from Mendele'sKitser masoes Binyomin hashlishi(The Brief Travels of Benjamin the Third). This novel, first published in 1878, represents the initial appearance of the Red Jews in modern Yiddish literature. This comical travelogue describes the adventures of Benjamin, who sets off in search of the legendary Red Jews. But who are these Red Jews or, in Yiddish,di royte yidelekh? The term denotes the Ten Lost Tribes of Israel, the ten tribes that in biblical times had composed the Northern Kingdom of Israel until they were exiled by the Assyrians in the eighth century BCE. Over time, the myth of their return emerged, and they were said to live in an uncharted location beyond the mysterious Sambatyon River, where they would remain until the Messiah's arrival at the end of time, when they would rejoin the rest of the Jewish people.
From Slavery to Freedom: Abolitionist Expressions in Maskilic Sea Adventures
Authors: Wolpe Rebecca
Published: April 2012

“Black” themes held a substantial place in twentieth-century American Yiddish poetry and prose, as well as in Yiddish journalism. As Hasia Diner notes in her work on Jews and blacks in the United States in the twentieth century, Jews sympathized with the plight of American blacks and their fight for civil rights. However, this had not always been the case, as evidenced by the many staunch Jewish supporters of slavery and Jewish slave owners and traders. Jonathan Schorsch claims that “under the sign of theHaskala…little changed” in this respect. In discussing a reference by Isaac Satanov to black slavery, Schorsch notes:

One cannot gauge from this brief comment whether Satanov knew about the abolitionist movements beginning to agitate in England and France at the time. Satanov's reportage was remarkably non-committal, betraying little, if any, sympathy for these developments.
Ashes to Outcasts: Cremation, Jewish Law, and Identity in Early Twentieth-Century Germany
Authors: Ferziger Adam S.
Published: April 2012

When Chief Rabbi Ḥayim (Vittorio) Castiglioni of Rome (b. 1840) passed away in 1911, he was cremated as per his request and his ashes were then buried in the Jewish cemetery of his native Trieste. One local Jewish newspaper pointed out that Castiglioni's position—cremation is permitted according to Jewish law and is even preferable to traditional burial—was definitely a minority one within the Italian rabbinate. By no means, however, was he accused by any of his rabbinic colleagues of being a heretic.
Variations in functional decomposition for an existing product: Experimental results
Authors: Eckert Claudia , Ruckpaul Anne , Alink Thomas , Albers Albert
Published: April 2012

This paper describes the findings of an experiment on how different engineers understand notions of function and functional breakdown in the context of design by modification. The experiment was conducted with a homogenous group of 20 design engineers, who had all received the same education. The subjects were asked to analyze how a hydraulic pump works and summarize their understanding in a function tree. The subjects were given either the hydraulic pump itself (with part of its casing removed) or a maintenance drawing that showed a section cut of the pump. This paper shows typical outputs of the designers. It discusses the different notions of function that the subjects had and the differences in the function trees they generated. The paper focuses an eight detailed analyses to show the range of approaches the subjects took.
Hierarchical structuring of layout problems in an interactive evolutionary layout system
Authors: Koenig Reinhard , Schneider Sven
Published: April 2012

This paper focuses on computer-based generative methods for layout problems in architecture and urban planning with special regard for the hierarchical structuring of layout elements. The generation of layouts takes place using evolutionary algorithms, which are used to optimize the arrangement of elements in terms of overlapping within a given boundary and the topological relations between them. In this paper, the approach is extended by a data structure that facilitates the hierarchical organization of layout elements making it possible to structure and organize larger layout problems into subsets that can be solved in parallel. An important aspect for the applicability of such a system in the design process is an appropriate means of user interaction. This depends largely on the calculation speed of the system and the variety of viable solutions. These properties are evaluated for hierarchical as well as for nonhierarchical structured layout problems.
A computational approach to biologically inspired design
Authors: Nagel Jacquelyn K.S. , Stone Robert B.
Published: April 2012

The natural world provides numerous cases for analogy and inspiration in engineering design. During the early stages of design, particularly during concept generation when several variants are created, biological systems can be used to inspire innovative solutions to a design problem. However, identifying and presenting the valuable knowledge from the biological domain to an engineering designer during concept generation is currently a somewhat disorganized process or requires extensive knowledge of the biological system. To circumvent the knowledge requirement problem, we developed a computational approach for discovering biological inspiration during the early stages of design that integrates with established function-based design methods. This research defines and formalizes the information identification and knowledge transfer processes that enable systematic development of biologically inspired designs. The framework that supports our computational design approach is provided along with an example of a smart flooring device to demonstrate the approach. Biologically inspired conceptual designs are presented and validated through a literature search and comparison to existing products.
Habitat use and circadian pattern of Solitary Tinamou Tinamus solitarius in a southern Brazilian Atlantic rainforest
Authors: KUHNEN VANESSA V. , DE LIMA R. E. M. , SANTOS J. F. , MACHADO FILHO L. C. P.
Published: April 2012

Solitary Tinamou Tinamus solitarius is a threatened Brazilian bird, and very little is known about its ecology and behaviour. In this study we aimed to verify the use of habitats in different stages of plant succession and the circadian activity pattern of the species. The study was conducted in Santa Catarina state (27º43’S, 48º49’W). Six camera traps were used to record the species in three areas of different successional stages during a 12-month period. Traps remained at each sample site for two months, after which they were moved to a new site, a minimum distance of 100 m apart. A total of 76 independent records of Solitary Tinamou were obtained, and its habitat use was found to be different within the three successional stages (P = 0.02). The majority of 54 independent records were obtained in the secondary forest; not one photo of the species was taken in the most degraded area. Solitary Tinamou exhibited a crepuscular pattern of activity, with most records (n = 38) taken at 07h00 and 06h00, and it appears to be sensitive to forest clearance.
Celebrating the End of School Life: A Pilot Study
Authors: Hutton Alison , Roderick Allison , Munt Rebecca , Mayner Lidia , Kako Mayumi , Arbon Paul
Published: April 2012

Introduction: Celebrating the end of secondary schooling (“Schoolies Festival”) is an established part of the school culture in Australia, with thousands of young students converging at beachside locations to celebrate this rite of passage. The aim of this study was to identify what young people believe is important to remain safe and healthy at this mass-gathering event.

Methods: This study was conducted using postcard surveys requesting demographic data and responses to the questions: (1) What do you think is important to stay safe and healthy at this event?; (2) What do you think is risky attending this event?; (3) Which of these is most likely to affect you at this event?; and (4) Where would you seek medical support? The surveys were distributed to attendees of a “Schoolies Festival” in Adelaide, Australia in 2008.

Results: One hundred sixty-five of the 300 postcards were returned completed. The average age of the respondents was 17.7 years. “Not using drugs” was considered important to staying safe and healthy by 120 (73%) of respondents; “drinking alcohol responsibly” was considered important by 89 (54%); and “violent behavior” and “exposure to illicit drugs” were identified as important risks by 135 (82%) and 98 (59%) of participants, respectively. Only 35 (21%) of respondents indicated that they would seek on-site health care if needed.

Conclusion: Young people attending mass-gathering celebrations have valid concerns about drinking responsibly, exposure to illicit drugs, and sexual harassment. Health messages or health promotion strategies aimed at their specific concerns would be helpful in the mitigation of illness or injury at such events.
Increasing Emergency Medicine Residents’ Confidence in Disaster Management: Use of an Emergency Department Simulator and an Expedited Curriculum
Authors: Franc Jeffrey Michael , Nichols Darren , Dong Sandy L.
Published: April 2012

Introduction: Disaster Medicine is an increasingly important part of medicine. Emergency Medicine residency programs have very high curriculum commitments, and adding Disaster Medicine training to this busy schedule can be difficult. Development of a short Disaster Medicine curriculum that is effective and enjoyable for the participants may be a valuable addition to Emergency Medicine residency training.

Methods: A simulation-based curriculum was developed. The curriculum included four group exercises in which the participants developed a disaster plan for a simulated hospital. This was followed by a disaster simulation using the Disastermed.Ca Emergency Disaster Simulator computer software Version 3.5.2 (Disastermed.Ca, Edmonton, Alberta, Canada) and the disaster plan developed by the participants. Progress was assessed by a pre- and post-test, resident evaluations, faculty evaluation of Command and Control, and markers obtained from the Disastermed.Ca software.

Results: Twenty-five residents agreed to partake in the training curriculum. Seventeen completed the simulation. There was no statistically significant difference in pre- and post-test scores. Residents indicated that they felt the curriculum had been useful, and judged it to be preferable to a didactic curriculum. In addition, the residents’ confidence in their ability to manage a disaster increased on both a personal and and a departmental level.

Conclusions: A simulation-based model of Disaster Medicine training, requiring approximately eight hours of classroom time, was judged by Emergency Medicine residents to be a valuable component of their medical training, and increased their confidence in personal and departmental disaster management capabilities.
Prehospital Trauma System Reduces Mortality in Severe Trauma: A Controlled Study of Road Traffic Casualties in Iraq
Authors: Murad Mudhafar Karim , Issa Dara B. , Mustafa Farhad M. , Hassan Hlwa O. , Husum Hans
Published: April 2012

Introduction: In low-resource communities with long prehospital transport times, most trauma deaths occur outside the hospital. Previous studies from Iraq demonstrate that a two-tier network of rural paramedics with village-based first helpers reduces mortality in land mine and war-injured from 40% to 10%. However, these studies of prehospital trauma care in low-income countries have been conducted with historical controls, thus the results may be unreliable due to differences in study contexts. The aim of this study was to use a controlled study design to examine the effect of a two-tier prehospital rural trauma system on road traffic accident trauma mortality.

Methods: A single referral surgical hospital was the endpoint in a single-blinded, non-randomized cohort study. The catchment areas consisted of some districts with no formal Emergency Medical Services (EMS) system, and other districts where 95 health center paramedics had been trained and equipped to provide advanced life support, and 5,000 laypersons had been trained to give on-site first aid. The hospital staff registered trauma mortality and on-admission physiological severity blindly. Assuming that prehospital care would have no significant impact on mortality in moderate injuries, only road traffic accident (RTA) casualties with an Injury Severity Score (ISS) ≥9 were selected for study.

Results: During a three-month study period, 205 patients were selected for study (128 in the treatment group and 77 in the control group). The mean prehospital transit time was approximately two hours. The two groups were comparable with regards to demographic characteristics, distribution of wounds and injuries, and mean anatomical severity. The mortality rate was eight percent in the treatment group, compared to 44% in the control group (95% CI, 25%–48%). Adjusted for severity differences between the treatment and control groups, prehospital care was a significant contributor to survival.

Conclusion: Where prehospital transport time is long, a two-tier prehospital system of trained paramedics and layperson first responders reduces trauma mortality in severe RTA injuries. The findings may be valid for civilian Emergency Medical Services interventions in other low-resource countries.