bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser keyhole welding of stainless steel thin plate stack for applications in fuel cell manufacturing
Authors: Tan W. , Shin Y. C.
Published: February 2015

An investigation based on both experimental and numerical approaches is presented in this paper on laser keyhole welding processes to join stacks consisting of multiple stainless steel plates. The welding parameters are shown to be decisive factors for weld penetration depth and welding productivity. The cooling rate varies with welding parameters and the location of solidification sites, and it directly determines the primary dendrite arm spacing for the columnar dendrites inside the weld zone. The joint fails in coach peel tests when the loading pressure is 93.4 MPa, and the fracture surface shows a mixed brittle and ductile mode. The corrosion resistance of the weld to the polymer electrolyte membrane fuel cell working environment is comparable to that of the substrate.
Effect of plasma electrolytic oxidation coating on joining metal to plastic
Authors: Liu F. C. , Liao J. , Gao Y. , Nakata K.
Published: February 2015

Joining of magnesium alloy to polyethylene without adhesive using a newly developed friction lap welding technology was investigated. The polyethylene and magnesium alloy were hard to be joined together without surface premodification due to the lack of polar groups on polyethylene surfaces. Strong hybrid joints were achieved after the polyethylene was treated by corona discharge, and the magnesium alloy was subjected to plasma electrolytic oxidation treatment. Scanning electron microscope and high resolution transmission electron microscope observations demonstrated that the high joining strength was attributed to the development of both chemical bonds at the interface and micromechanical interlocking.
Endogenous plasminogen activators mediate progressive intracerebral hemorrhage after traumatic brain injury in mice
Authors: Hijazi Nuha , Abu Fanne Rami , Abramovitch Rinat , Yarovoi Serge , Higazi Muhamed , Abdeen Suhair , Basheer Maamon , Maraga Emad , Cines Douglas B. , Al-Roof Higazi Abd
Published: February 2015

Key Points

Closed head trauma sequentially releases tPA followed by uPA from injured brain. Increased uPA is responsible for delayed intracerebral hemorrhage, which is prevented by a tPA variant that inhibits uPA activity.
Influence of semiconductor and metal nanoparticles on the dielectric properties of ionic matrix cadmium octanoate
Authors: Zhulai Dmytro , Fedorenko Denys , Kovalchuk Alexander , Bugaychuk Svetlana , Klimusheva Gertruda Vasylivna , Mirnaya Tetyana Alfredivna
Published: February 2015

Dielectric properties of ionic composites consisted of cadmium octanoate matrix and semiconductor or metal nanoparticles have been investigated. The nanoparticles of different nature (semiconductor CdS, metal Au, and metal core-semiconductor shell Au-CdS) were chemically synthesized in the smectic A phase of (Cd+2(C7H15COO)−2, CdC8) that was used as a nanoreactor. These nanocomposites are very stable and well ordered; the size and shape of the nanoparticles (NPs) are well controlled during the synthesis. The main aim of the research was to examine the influence of nanoparticles on the dielectric properties of ionic matrix, which has smectic A ordered structure. Electrical characteristics were investigated at different temperatures, which correspond to different phases of the material. The conductivity of nanocomposites has an activation nature. The electrical conductivity anisotropy confirms the structural anisotropy of the nanocomposites. The conductivity of the nanocomposite along the cation-anion layers is higher by 2 orders of magnitude than that across the cation-anion layers. Basing on the experimental data, we proposed the simple model of the charge carriage process.
Can yeast isolation be predicted in complicated secondary non-postoperative intra-abdominal infections?
Authors: Dupont Hervé , Guilbart Mathieu , Ntouba Alexandre , Perquin Mélanie , Petiot Sandra , Regimbeau Jean-Marc , Chouaki Taieb , Mahjoub Yazine , Zogheib Elie
Published: February 2015

Introduction

The aim of this study was to create a predictive score for yeast isolation in patients with complicated non-postoperative intra-abdominal infections (CNPIAI) and to evaluate the impact of yeast isolation on outcome.

Methods

All patients with a CNPIAI undergoing emergency surgery over a three-year period were included in the retrospective cohort (RC, n = 290). Patients with a yeast-positive peritoneal fluid culture (YP) were compared with patients with a yeast-negative culture (YN). Multivariate logistic regression was used to identify factors independently associated with yeast isolation and a predictive score was built. The score’s performance was then established in the prospective cohort (PC, n = 152) over an 18-month period. Outcome of the whole cohort was evaluated and independent risks factors of mortality searched.

Results

In the RC, 39 patients (13.4%) were YP. Four factors were independently associated with the YP group: length of stay before surgery ≥48 h (odds ratio (OR) (95% confidence interval (CI)) = 3.1 (1.4 to 6.9),P = 0.004, 1 point), per-operative cardiovascular failure (2.4 (1.1 to 5.8),P = 0.04, 1 point), generalized peritonitis (6.8 (2.7 to 16.7),P<0.001, 2 points) and upper gastrointestinal tract perforation (2.5 (1.2 to 5.6),P = 0.02, 1 point). In the PC, the area under the curve (95%CI) of the predictive score’s receiver operating characteristic curve was 0.79 (0.72 to 0.86). For predicting an intra-abdominal candidiasis (IAC), a score ≥3 had a sensitivity of 0.60, a specificity of 0.84, a positive predictive value of 0.49 and a negative predictive value of 0.89. Furthermore, yeast isolation was associated with worse outcome and independently associated with mortality in the whole cohort (OR = 2.15; 95%CI (1.03 to 4.46),P = 0.04).

Conclusions

The new predictive score can be used to rule out intra-abdominal candidiasis and thus avoid the initiation of antifungal treatment. It is suited to less severe infections than previously published scores. IAC is associated independently with an increased mortality in this population.
Comparison of false positive rates for screening breast magnetic resonance imaging (MRI) in high risk women performed on stacked versus alternating schedules
Authors: Othman Edress , Wang Jue , Sprague Brian L , Rounds Tiffany , Ji YongLi , Herschorn Sally D , Wood Marie E
Published: February 2015

Purpose

Breast MRI added to mammography increases screening sensitivity for high-risk women but false-positive (FP) rates are higher and the optimal screening schedule for coordination with mammography is unclear. We compare rates of FP MRI when studies were performed on two different schedules.

Patients and methods

High-risk women at the University of Vermont who had at least 1 MRI and 1 mammogram performed within one year between 2004–2012 were eligible for inclusion in this study. Screening was considered stacked if both studies were performed within 90 days and alternating if studies were 4–8 months apart. False positive was defined in one of three ways.

Results

137 women had screening which met inclusion criteria and 371 MRIs were reviewed. The FP rates were similar for the two schedules when considering BI-RAD 4, 5, 0 or biopsy as a positive test. FP rates were significantly higher for the stacked schedule (18.2 vs. 10.2%, p = 0.026) when considering BI-RADS 3-4-5-0 as positive test, due to the elevated rate of BI-RADS 3 assessments among stacked exams.

Conclusion

False positive rates differ based on the type of exam (baseline or subsequent) and definition of positive but do not differ based on imaging schedule (stacked or alternating); suggesting that women and their providers may choose the imaging schedule they prefer. This is significant as a randomized clinical trial comparing the two schedules is not likely to be performed, given the high cost and large number of women needed for such a study.
Effects of cold-treatment and strain-rate on mechanical properties of NbTi/Cu superconducting composite wires
Authors: Guan Mingzhi , Wang Xingzhe , Zhou Youhe
Published: February 2015

During design and winding of superconducting magnets at room temperature, a pre-tension under different rate is always applied to improve the mechanical stability of the magnets. However, an inconsistency rises for superconductors usually being sensitive to strain and oversized pre-stress which results in degradation of the superconducting composites’ critical performance at low temperature. The present study focused on the effects of the cold-treatment and strain-rate of tension deformation on mechanical properties of NbTi/Cu superconducting composite wires. The samples were immersed in a liquid nitrogen (LN2) cryostat for the adiabatic cold-treatment, respectively with 18-hour, 20-hour, 22-hour and 24-hour. A universal testing machine was utilized for tension tests of the NbTi/Cu superconducting composite wires at room temperature; a small-scale extensometer was used to measure strain of samples with variable strain-rate. The strength, elongation at fracture and yield strength of pre-cold-treatment NbTi/Cu composite wires were drawn. It was shown that, the mechanical properties of the superconducting wires are linearly dependent on the holding time of cold-treatment at lower tensile strain-rate, while they exhibit notable nonlinear features at higher strain-rate. The cold-treatment in advance and the strain-rate of pre-tension demonstrate remarkable influences on the mechanical property of the superconducting composite wires.
PNPLA3 I148M associations with liver carcinogenesis in Japanese chronic hepatitis C patients
Authors: Nakaoka Kazunori , Hashimoto Senju , Kawabe Naoto , Nitta Yoshifumi , Murao Michihito , Nakano Takuji , Shimazaki Hiroaki , Kan Toshiki , Takagawa Yuka , Ohki Masashi , Kurashita Takamitsu , Takamura Tomoki , Nishikawa Toru , Ichino Naohiro , Osakabe Keisuke , Yoshioka Kentaro
Published: February 2015

Aim

To investigate associations between patatin-like phospholipase domain-containing 3 (PNPLA3) genotypes and fibrosis and hepatocarcinogenesis in Japanese chronic hepatitis C (CHC) patients.

Methods

Two hundred and thirty-one patients with CHC were examined for PNPLA3 genotypes, liver stiffness measurements (LSM), and hepatocellular carcinoma (HCC) from May 2010 to October 2012 at Fujita Health University Hospital. The rs738409 single nucleotide polymorphism (SNP) encoding for a functional PNPLA3 I148M protein variant was genotyped using a TaqMan predesigned SNP genotyping assay. LSM was determined as the velocity of a shear wave (Vs) with an acoustic radiation force impulse. Vs cut-off values for cirrhosis were set at 1.55 m/s. We excluded CHC patients with a sustained virological response or relapse after interferon treatment.

Results

PNPLA3 genotypes were CC, CG, and GG for 118, 72, and 41 patients, respectively. Multivariable logistic regression analysis selected older age (OR = 1.06; 95% CI: 1.03–1.09; p < 0.0001), higher body mass index (BMI) (OR= 1.12; 95% CI: 1.03–1.22; p = 0.0082), and PNPLA3 genotype GG (OR = 2.07; 95% CI: 0.97–4.42; p = 0.0599) as the factors independently associated with cirrhosis. When 137 patients without past history of interferon treatment were separately assessed, multivariable logistic regression analysis selected older age (OR = 1.05; 95% CI: 1.02–1.09; p = 0.0034), and PNPLA3 genotype GG (OR = 3.35; 95% CI: 1.13–9.91; p = 0.0291) as the factors independently associated with cirrhosis. Multivariable logistic regression analysis selected older age (OR = 1.12; 95% CI: 1.07–1.17; p < 0.0001), PNPLA3 genotype GG (OR = 2.62; 95% CI: 1.15–5.96; p = 0.0218), and male gender (OR = 1.83; 95% CI: 0.90–3.71); p = 0.0936) as the factors independently associated with HCC.

Conclusion

PNPLA3 genotype I148M is one of risk factors for developing HCC in Japanese CHC patients, and is one of risk factors for progress to cirrhosis in the patients without past history of interferon treatment.
What should social work learn from ‘the fire of social movements that burns at the heart of society’?
Authors: Smith Linda Harms
Published: February 2015

That social work should be ‘on the side of the poor and the oppressed’ in the context of the ubiquitous and increasingly pernicious consequences of global neoliberal capitalism, demands a differently engaged practice (Dominelli, 2004; Ferguson and Lavalette, 2006; Ferguson, 2008; Reisch, 2013; Sewpaul, 2013). This requires ‘greater system destabilising and social change efforts, and not the traditional social control and status-quo-maintaining functions of social work’ (Sewpaul, 2013: 23). The struggles for social and economic justice waged by global and local social movements may therefore provide insights and impetus for such ‘differently engaged’ radical and transformative practice. This article explores the processes and strategies of two South African social movements and suggests that social work should incorporate some of the discourses of these movements for expansion of its theoretical base for transformation and social change.
Cardiolipin and Its Different Properties in Mitophagy and Apoptosis
Authors: Li Xiao-Xiao , Tsoi Bun , Li Yi-Fang , Kurihara Hiroshi , He Rong-Rong
Published: February 2015

Cardiolipin (CL) is a unique dimeric phospholipid that exists almost exclusively in the inner mitochondrial membrane (IMM) in eukaryotic cells. Two chiral carbons and four fatty acyl chains in CL result in a flexible body allowing interactions with respiratory chain complexes and mitochondrial substrate carriers. Due to its high content of unsaturated fatty acids, CL is particularly prone to reactive oxygen species (ROS)-induced oxidative attacks. Under mild mitochondrial damage, CL is redistributed to the outer mitochondrial membrane (OMM) and serves as a recognition signal for dysfunctional mitochondria, which are rapidly sequestered by autophagosomes. However, peroxidation of CL is far greater in response to severe stress than under normal or mild-damage conditions. The accumulation of oxidized CL on the OMM results in recruitment of Bax and formation of the mitochondrial permeability transition pore (MPTP), which releases Cytochrome c (Cyt c) from mitochondria. Over the past decade, the significance of CL in the function of mitochondrial bioenergy has been explored. Moreover, approaches to analyzing CL have become more effective and accurate. In this review, we discuss the unique structural features of CL as well as the current understanding of CL-based molecular mechanisms of mitophagy and apoptosis.
Edges of water and land: Transnational performance practices in indigenous/settler collaborations
Authors: Kuppers Petra
Published: February 2015

This essay engages collaborative art projects in a field of settler/indigenous relations: drumming and performances of self at a Michigan language revitalization symposium, Native Women Language Keepers; Anishinaabe artist Rebecca Belmore’s iconic video performance work at the Canadian pavilion of the Venice Biennial; and the Australian community cultural development project Ghost Nets, which emphasizes relationships while cleaning up fishing debris off beaches. The essay argues for reading strategies that acknowledge relational living, in the flow of history, speaking from webs of more than one voice, and attending to gaps.
Reviews
Authors: Maclaurin Ali , Kerr David
Published: February 2015

Refugee Performance: Practical Encounters, Michael Balfour (2013) Brisol: Intellect, 316 pp., ISBN 978-1-84150-637-1 (hbk) £45

Applied TheaTRICKs: Essays in Refusal, Syed Jamil Ahmed (2013) Kolkata: Anderson Printing House, 123 pp., ISBN: 9788190671927, Rp300, USD10 outside India + postage
The dark side of phrónesis: revisiting the political incompetence of philosophy
Authors: Krajewski Bruce
Published: February 2015

In his Ethics, Aristotle joins sophrosúne and phrónesis as synonyms. In approximately the same time frame, Xenophon provides a Wittgensteinian account of a go-and-look instance of what sophrosúne looked like in one ancient Greek context. We have a disturbing description of sophrosúne in action. It leaves a reader with quitea different picture of the meaning of these two key words from the staid, peaceful, deliberative contemporary interpretations, particularly in Continental philosophy, that attempt to make both phrónesis and sophrosúne the foundation for a praiseworthy ethics and politics. Continental philosophers like Martin Heidegger and Hans-Georg Gadamer attended closely to Aristotelian phrónesis (not the Xenophonic variety), but were unable to put that learning into practice in their own ethical and political lives, making one wonder why followers of Heidegger and Gadamer continue to insist on ethical programs based in the Heideggerian and Gadamerian phronetic tradition, where Aristotle has supplanted Odysseus as the model most associated with phrón?sis and sophrosúne.
Ejercicios espirituales e intelectualismo en Epicteto
Authors: Braicovich Rodrigo Sebastián
Published: February 2015

El objetivo central del presente trabajo consistirá en poner en cuestión la validez de la interpretación ofrecida por Pierre Hadot, Michel Foucault y John Sellars de la noción de áskesis en Epicteto. Si bien dicho cuestionamiento ha sido sugerido ya por John Cooper, mi objetivo será mostrar en qué sentido específico los ‘ejercicios espirituales’ de Epicteto no constituyen (contra lo sugerido por Hadot, Foucault y Sellars) otra cosa que procesos estrictamente cognitivos. Con este objetivo en mente recurriré al concepto de preconcepciones (prolépseis) desarrollado por Epicteto, a fin de dotar de contenido a la distinción, ya presente en el estoicismo antiguo, entre asentimiento débil y asentimiento firme.
As Bucólicas de Virgílio e o epigrama 8.55 de Marcial: intertextualidade, mecenato e uma recusatio implícita
Authors: Cesila Robson Tadeu
Published: February 2015

Este artigo analisa os fortes elementos intertextuais que relacionam o epigrama 55 do livro 8 de Marcial com as Bucólicas de Virgílio, especialmente as de número 1, 2 e 9. Incorporando esses elementos de forma e conteúdo trazidos dos poemas virgilianos, Marcial constrói, nesse habilidoso epigrama metapoético, uma “biografia” do poeta de Mântua muito útil na defesa da ideia da necessidade de apoio material aos escritores para o surgimento de grandes obras literárias; ao mesmo tempo, por meio de uma recusatio que fica implícita nos últimos versos do epigrama, Marcial aborda a questão dos gêneros poéticos e justifica, como em tantos outros passos de sua obra, a sua opção pela poesia ligeira.
Intimately Bound to Numbers: On the Rhetorics of GLBTQ School Climate Research
Authors: Thorpe Justin N. , Greteman Adam J.
Published: February 2015

The GLBTQ research community has become, in some ways, bound to using quantification within their arguments about the changes that are being recommended for schools and the lives of GLBTQ youth. This article considers the rhetorical nature of quantification when arguing for such changes. This article draws from the Gay, Lesbian, and Straight Educational Network’s 2009 National School Climate Survey report, a report that has become central to the discourses concerning GLBTQ youth, including use in television, news media, and academic research. This article begins by considering the nature of rhetoric and how quantification has come to play such an important part in social science writing and argumentation. The article then critiques how quantificational rhetoric is deployed as a tool of fear, guilt, safety and accountability as evidenced in the National School Climate report.
Heat and mass transfer in binary film evaporation and condensation in vertical channel
Authors: Nasr Abdelaziz , S. Al-Ghamdi Abdulmajeed
Published: February 2015

Evaporation and condensation in the presence of binary liquid film flowing on one of two parallel vertical plates by mixed convection have been studied numerically. The first plate is adiabatic and wetted by a binary liquid film while the second one is dry and isothermal. The results concern the effects of the inlet parameters on the ethylene glycol evaporation and on the water condensation. Results obtained show that the increase of the inlet vapor concentration of water benefits its condensation and the increase of the inlet vapor concentration of ethylene glycol inhibits its evaporation.
The Square-Root Rule for Reinsurance: Further Analysis and Consideration of China’s Market
Authors: Du Nan , Zeng Zhangrong , Viswanathan Krupa
Published: February 2015

China has been experiencing rapid development in its insurance market in recent years, with its reinsurance market also in a developing stage. Previous theoretical work using a game theory approach suggests that the appropriate number of companies in the insurance market should be the square root of the number of insurers (index = 0.5). To verify the validity of this square-root rule, we conduct an analysis using data over a period. To examine this relationship between the number of insurers and the number of reinsurers, we perform regression analyses using data from the Organization for Economic Cooperation and Development (OECD). We find that the level of the index fluctuates around an index level of 0.4, instead of 0.5, the optimal value by theory. We also observe that this index level fluctuation behaves similar to the price of risk and the property–liability combined ratio. In our analysis, we then replace the number of reinsurers and number of insurers by ceded premium and net premium, respectively, and find similar results. By comparing and calculating these theoretical relationships, we present two formulas of the average size of the reinsurance market with our interpretations on the gap between the theory and the data. In addition, we analyze the Chinese reinsurance market to offer more evidence of our interpretation.
Three open questions in experimental syntax
Authors: Sprouse Jon
Published: February 2015

This article presents a review of current research in experimental syntax, with a focus on three open questions and the (methodo)logical tools that have been developed to explore them. The three questions are: (1) Are the published data underlying syntactic theories valid?, (2) How can we determine the source of acceptability judgment differences?, and (3) What do gradient judgments tell us about the architecture of the grammar? The hope is that these three questions will illustrate the fundamental connection between experimental syntax and theoretical syntax, provide concrete demonstrations of the value of the tools of experimental syntax (e.g., random sampling, factorial logic, and gradient judgments), and point to new directions for future research.
Crystal structure of catena[(tetraaqua-bis(μ2-(4,4'-bipyridine-κ2N:N'))- nickel(II)][(diaqua-bis(3-methyl-4-amino-benzensulphonate-κ1O)-bis(μ2- (4,4'-bipyridine-κ2N:N'))nickel(II)]—3-methyl-4-aminobenzensulphonate— ethanol (1:2:2), C52H72N8Ni2O20S4
Authors: Han Min-Le , Du De-Guang
Published: February 2015

C52H72N8Ni2O20S4, orthorhombic, P21212 (no. 18), a = 14.604(1) Å, b = 18.865(2) Å, c = 11.0673(9) Å, V = 3048.9 Å3, Z = 2, Rgt(F) = 0.0282, wRref(F2) = 0.0727, T = 296 K.
Crystal structure of a new alkaline-cadmium carbonate Li2RbCd(CO3)2F, C2CdFLi2O6Rb
Authors: Chen Jie , Luo Min , Ye Ning
Published: February 2015

C2CdFLi2O6Rb, hexagonal, P63/m (no. 176), a = 4.915(4) Å, c = 15.45(1) Å, V = 323.3 Å3, Z = 2, Rgt(F) = 0.0242, wRref(F2) = 0.0571, T = 293 K
Race and Justice in The Bahamas: The Case of Louis Powles
Authors: Wilmot Swithin R.
Published: February 2015

A brief history of the short tenure of Louis Diston Powles as stipendary magistrate in the Bahama Islands, November 1886-June 1887.
GaN/SiC Epitaxial Growth for High Power and High Switching Speed Device Applications
Authors: Sun Zheng , Usami Shigeyoshi , Lu Di , Ishii Takahiro , Olsson Marc , Yamashita Kouhei , Mitsunari Tadashi , Honda Yoshio , Amano Hiroshi
Published: February 2015

We developed a new GaN on SiC growth method by metalorganic vapour phase epitaxy (MOVPE) using of a single 2-dimension-growth step. Prior to epitaxy, to inhibit pre-reaction of Si-face SiC substrate with TMGa and NH3, TMAl was flowed without NH3. 1.5 μm of undoped crack-free GaN was grown on 6H-SiC (Si-face). Without buffer layer, the vertical resistance of GaN/SiC structure was found to be around 82.1Ω as determined by I-V characteristic. Further reduction in vertical resistance is expected by growth of n-GaN (1.5μm)/SiC structure (300μm). We also expect a SiC-based GaN heterostructure vertical FET will achieve high power and high switching speed performance.
Impact of Nitridation on Structural and Optical Properties of Epitaxial GaN Films Grown on M-Plane Sapphire by PAMBE
Authors: Mukundan Shruti , Mohan Lokesh , Chandan Greeshma , Roul Basanta , Krupanidhi S.B.
Published: February 2015

GaN epilayers were grown on m-plane (10-10) sapphire substrates using plasma assisted molecular beam epitaxy. Impact of nitridation on structural and optical properties of GaN film was investigated. The film grown on a nitridated surface resulted in a nonpolar (10-10) orientation while without nitridation caused a semipolar (11-22) orientation. The high resolution X-ray diffraction studies confirmed the orientation of the GaN films. X-ray rocking curve showed better crystallinity of semipolar as compared to nonpolar GaN. Atomic force microscopy showed smoother films in case of nonpolar GaN which might be in account of the nitridation treatment. Room temperature photoluminescence study showed nonpolar GaN to have higher value of compressive strain as compared to semipolar GaN film, which was further confirmed by room temperature Raman spectroscopy. Despite the fact that it is difficult to obtain high-quality nonpolar material due to the planar anisotropic nature of the growth mode, we hereby report the development of non-polar GaN of usable quality, on an m-plane sapphire, involving controlled steps of nitridation.
Thermodynamical Properties and Stability of Crystalline Membranes in the Quantum Regime
Authors: Amorim B. , Roldán R. , Cappelluti E. , Fasolino A. , Guinea F. , Katsnelson M. I.
Published: February 2015

We study the thermodynamical properties and lattice dynamics of two-dimensional crystalline membranes, such as graphene and related compounds, in zero temperature limit, where quantum effects are dominant. We find out that, just as in the high temperature classical limit, a fundamental role is played by the anharmonic coupling between in-plane and out-of plane lattice modes, which leads to a strong reconstruction of the dispersion relation of the out-of-plane mode. We identify a crossover temperature, T*, bellow which quantum effects are dominant. We estimate that for graphene T* ∼ 70 - 90 K. Inclusion of anharmonic effects makes the thermal expansion finite in the thermodynamic limit, and below T* it tends to zero as a power law as T→0 as required by the third law of thermodynamics. The specific heat also goes to zero as a power law as T→0, but with a exponent that differs from the one predicted by the harmonic theory.
A Comprehensive Study of Effect of Composition on Resistive Switching of HfxAl1-xOy based RRAM devices by Combinatorial Sputtering
Authors: Kumbhare Pankaj , Meihar Paritosh , Rajarathinam Senthilkumar , Chouhan Shikhar , Pai Suhit , Panwar Neeraj , Ganguly U.
Published: February 2015

We use the combinatorial sputter technique to simultaneously sputter HfO2 and Al2O3 targets to obtain a film of HfxAl1-xOy of specific compositions. The effect of oxide thickness, oxide composition (i.e. Hf:Al ratio) and oxygen gettering layer thickness on DC sweep based resistive switching performance of RRAM is investigated. The oxide thickness primarily affects forming voltage and causes the memory window to increase for the thinnest oxide (6 nm, other thicknesses – 12 nm, 18 nm). The composition of oxide has a non-linear effect on the memory window (high to low resistance ratio) and variability of resistance states whereas the variability of set voltage improves significantly for ternary oxide compared to individual binary oxides. Finally, electrode interlayer for oxygen-gettering is also critical where a thin Ti layer of 1.5nm maintains the memory window but reduces variability in HRS, LRS, reduces Vset and Vreset and improves the variability in Vset.
Material and Device Parameters Influencing Multi-Level Resistive Switching of Room Temperature Grown Titanium Oxide Layers
Authors: Bousoulas P. , Michelakaki I. , Giannopoulos J. , Giannakopoulos K. , Tsoukalas D.
Published: February 2015

We present a detailed study of memory performance of titanium oxide (TiO2-x)-based resistive switching memories by modifying critical parameters of the films involved in the memory stack grown by reactive sputtering at room temperature. The device includes a Ti nanolayer at the Au/TiO2-x interface and it is defined by the following material stack: Au/Ti/TiO2-x/Au/SiO2/Si. We investigate the memory performance optimization of the device in terms of the Ti nanolayer thickness using as a starting point for the TiO2-x growth conditions these identified by varying the ratio of oxygen concentration to argon concentration by our previous results. Due to the superb ability of Ti to absorb oxygen atoms from the dielectric matrix, a large amount of oxygen vacancies is created, which are crucial for the stable function of the memory devices. We observe the existence of an optimum Ti thickness that if further increased gradually degrades the resistive switching behavior. The induced interface oxide thickness is found also to affect the fluctuation of the ON/OFF processes. In terms of electrical performance self-rectifying characteristics were recorded for all samples in the both resistance states. We then demonstrate that at least five-level resistance states could be obtained by modifying the compliance current, exhibiting excellent resistance uniformity and retention capability. The results are supported by C-AFM measurements demonstrating the scaling potential of the large area device discussed above.
Tailoring Industrial Scale CNT Production to Specialty Markets
Authors: Schauer Mark W. , White Meghann A.
Published: February 2015

The vast majority of industrial scale Carbon Nanotube (CNT) production involves short nanotubes (< 100 microns) that appear as a powder. These products are typically utilized as minor components (usually less than 2%) in polymers where they may or may not impart marginal improvements in composite properties. At Nanocomp Technologies we produce large-format CNT material by floating catalyst chemical vapor deposition. This technique produces very long CNTs (> 1 mm) in the gas phase, where entanglement produces large format material of exceptional strength and electrical conductivity. By manipulating the physics and chemistry of the process, the format and properties of the material can be controlled. Post-production processing further enhances the desired material properties. In this way applications such as Armor, Wiring and Cables for aerospace, and Integrated Energy Storage can be realized.
Unipolar resistive switching behavior of high-k ternary rare-earth oxide LaHoO3 thin films for non-volatile memory applications
Authors: Sharma Yogesh , Misra Pankaj , Pavunny Shojan P. , Katiyar Ram S.
Published: February 2015

Rare-earth oxides have attracted considerable research interest in resistive random access memories (ReRAMs) due to their compatibility with complementary metal-oxide semiconductor (CMOS) process. To this end we report unipolar resistive switching in a novel ternary rare-earth oxide LaHoO3 (LHO) to accelerate progress and to support advances in this emerging densely scalable research architecture. Amorphous thin films of LHO were fabricated on Pt/TiO2/SiO2/Si substrate by pulsed laser deposition, followed by sputter deposition of platinum top electrode through shadow mask in order to elucidate the resistive switching behavior of the resulting Pt/LHO/Pt metal-insulator-metal (MIM) device structure. Stable unipolar resistive switching characteristics with interesting switching parameters like, high resistance ratio of about 105 between high resistance state (HRS) and low resistance state (LRS), non-overlapping switching voltages with narrow dispersion, and excellent retention and endurance features were observed in Pt/LHO/Pt device structure. The observed resistive switching in LHO was explained by the formation/rupture of conductive filaments formed out of oxygen vacancies and metallic Ho atom. From the current-voltage characteristics of Pt/LHO/Pt structure, the conduction mechanism in LRS and HRS was found to be dominated by Ohm’s law and Poole-Frenkel emission, respectively.
Complementary Microscopy Platform for Investigations of Hybrid Nanostructures Comprising Quantum Dots and Plasmonic Particles
Authors: Dopf Katja , Schwab Patrick M. , Moosmann Carola , Habermehl Anne , Lemmer Uli , Eisler Hans-Juergen
Published: February 2015

Nanoscale systems combining colloidal quantum dots with plasmonic antennas will pioneer the development of novel nanodevices with tailored optical features for a wide range of applications. The interactions between such nanoparticles strongly depend on the particular distance. We propose the use of an atomic force microscope (AFM) to image and to position quantum dots with respect to plasmonic particles. Additionally, we analyze the arrangements with several optical characterization methods, such as confocal microscopy, fluorescence microscopy and superresolution optical fluctuation imaging (SOFI). These methods support each other and improve the AFM manipulation technique. The AFM tip is perfectly aligned to a focused laser by detecting the Raman signal of the silicon tip. Thus ultimately, we can simultaneously use the topography information with a spatial resolution in the range of the nanoparticle sizes and cross-correlate it with the optical characterization methods.
Chemical Fluid Deposition of Hf-Zr-O-based Thin Films using Supercritical Carbon Dioxide Fluid
Authors: Shiokawa Marina , Izaki Katsushi , Funakubo Hiroshi , Uchida Hiroshi
Published: February 2015

We propose some chemical processing procedures for fabricating thin films in Hf-Zr-O system by a unique film deposition technique using supercritical carbon dioxide fluid (scCO2), i.e., supercritical fluid deposition (SCFD), which would be an prospective approach for fabricating metal-oxide films for integrated circuits because of its unique characteristics; e.g., extraction ability, transportation capability, and reaction equilibrium etc., are quite favorable for the film deposition from metal-complex precursors.

The SCFD was accomplished in a closed batch-type reaction apparatus, consisting of two steps; (a) material deposition and (b) subsequent post-treatment under scCO2 atmosphere. Thin films of amorphous Hf-Zr-O were deposited on platinized silicon [(111)Pt/TiO2/(100)Si] substrates by SCFD using metal-complex precursors M[OCH(CH3)]2(C9H11O2)2 (M = Hf or Zr) at reaction temperature of 100 – 300 °C, significantly lower than those for MOCVD. These films possessed dielectric permittivity’s of approximately 20 – 25, comparable to those from conventional processes, although they still included residue of organic species that prompt the dielectric degradation under lower-frequency bias application.
Annealing effects on metal-ZnO interface for improvement performance of Thin-film Transistors
Authors: Dominguez Miguel A. , Flores Francisco , Luna Adan , Alcantara Salvador , Martinez Javier , Luna-Lopez Jose A. , Rosales Pedro , Reyes Claudia
Published: February 2015

In this work, the annealing effects at 180°C in Aluminum-ZnO contacts as function of time were studied. Also, the application in TFTs of ZnO films obtained at low-temperature (200°C) are presented. The ZnO films obtained by ultrasonic Spray Pyrolysis at 200 °C were deposited over Aluminum contacts on SiO2/Si wafers to demonstrate the use of active layer in thin-film transistors. The results show that an improvement can be obtained in metal-ZnO interfaces by low-temperature annealing treatments. However, long annealing time degrade the metal-ZnO interface and may affect the electrical performance of the device.
Facile Preparation of Well-Dispersed GO-SPEEK Composite Membranes by Electrospun for Fuel Cell Applications
Authors: Liu Xu , Meng Xiaoyu , Shi Chuanming , Huo Jiangbei , Cai Ziqing , Cui Lishan , Zhou Qiong
Published: February 2015

Graphene oxide (GO) is one of the most attractive inorganic nanofillers in proton exchange membranes (PEMs) for its large specific surface area and high proton conductivity. The proton conductivity of GO nanosheet is known to be orders of magnitude greater than the bulk GO, thus it is essential to improve the dispersion of GO nanosheets in the PEM matrix to achieve higher conductivity. In this study, we report a facile and effective method to fabricate a GO/sulfonated poly ether ether ketone (SPEEK) composite membrane with well-dispersed GO nanosheets in SPEEK matrix by using electrospinning technique for direct methanol fuel cell application. The composite membrane exhibits improved proton conductivity, dimensional stability and methanol barrier property due to the presence of well-dispersed GOs. It is believed that the GO nanosheets can not only induce continuous channels for proton-conducting via Grotthuss mechanism, but also act as methanol barriers to hinder the methanol molecules from passing through the membrane.
Crosscurricular Competencies in the Curriculum for Undergraduate degrees: Efforts of Bologna in University Quality/Competencias transversales en los planes de estudio de las titulaciones de grado: los esfuerzos de Bolonia en calidad universitaria
Authors: Aránguiz Salazar Cristián , Rivera Vargas Pablo
Published: February 2015

El presente texto de reflexión expone una investigación en desarrollo, respecto a los cambios curriculares que ha conllevado la implementacióndel marco de cualificaciones comparables en las titulaciones de grado, con relación a los descriptores genéricos, denominadoscompetencias transversales, a aplicar en las titulaciones de la Universidad de Barcelona. El nuevo proceso de enseñanza que se ha diseñadodesde la conformación del Espacio Europeo de Educación Superior (EEES), está profundamente vinculado a las transformaciones de lasociedad respecto al advenimiento de la sociedad del conocimiento y la sociedad de la información. En el plano económico de las relacionesde producción, así como la productividad vinculada a la innovación, exigen que la enseñanza universitaria se adecue a las redefinicionesdel mundo del trabajo. En el plano social, se asiste a la pluralización de la sociedad, generando el término de los supuestos incuestionablesdel proyecto de modernidad, así como la relativización de la hegemonía de las instituciones sociales y sus valores universales asociados.
Fragmentation as universality: The fear to hyper information in the society of knowledge/La fragmentación como universalidad: el miedo a la hiperinformación en la sociedad del conocimiento
Authors: Jiménez Batista Robin
Published: February 2015

Este artículo de reflexión propone una revisión a los conceptos: Sociedad de la ignorancia, Sociedad del desconocimiento y sociedad de la incultura. Se intenta demostrar cómo estos conceptos propuestos por los expertos Antoni Brey, Daniel Innerarity y Goncal Mayos responden a una corriente que enfrenta el determinismo tecnológico desde el determinismo sociológico, desconociendo el desarrollo desigual de los pueblos, las desigualdades entre la periferia y el centro y, por otra parte, desconocen que la recepción de la información se produce en consonancia con la fragmentación de la contemporaneidad y la multiplicidad de sentidos que esta encarna. Finalmente, nos ocuparemos en reflexionar cómo lo universal enfrenta el concepto de totalidad que arguyen estos y otros autores para aterrorizarse frente a la hiperinformación y la incapacidad de comprender las mediaciones.
Approach to the Securities Identity and Expressions of men and women in the Colombian Caribbean/Aproximación al identitario de valores y expresiones del hombre y la mujer en el Caribe colombiano
Authors: Mejía Mendoza Guillermo , Espinosa Patrón Alejandro
Published: February 2015

La reflexión sobre el ser Caribe corresponde a una visión integral formada en torno al hombre dentro de una región determinada.La investigación se hace desde el punto de vista de los valores, lo ontológico y lingüístico, para, de este modo, situar al hombreen su contexto cultural; aspecto este que lo hace aparecer como un ser autóctono y genuino en sus expresiones y en sus característicascomportamentales. La metodología del estudio respondió a lo cualitativo, aunque se tomaron ciertos datos cuantitativosque ayudaron a la conceptualización de la investigación.
The Science of Culture: Implications for Social Science Inquiries into Contemporary African Phenomenon/La ciencia de la cultura: implicaciones para las investigaciones de las Ciencias Sociales en el fenómeno africano contemporáneo
Authors: Hyman Sundjata ibn
Published: February 2015

Este artículo discute la cultura como una unidad de análisis dentro de la investigación en las ciencias sociales y su tratamiento más sistemático como un modelo dinámico e idiosincrático para el desarrollo humano, modelo cuya disposición lógica de axiomas interpretativos de “estructuras profundas” cosmológicas y ontológicas (axiomas de existencia para la organización colectiva y su funcionamiento) configura el objetivo y la naturaleza de conductas y praxis sociales abiertas (incluyendo símbolos, lengua, costumbres) e informa un plan general de vida que guía el comportamiento individual y las prácticas colectivas. Este enfoque conductista permite una rica elaboración de la cultura aclarando sus fundamentos cosmológicos, ontológicos y psicológicos, y las influencias en su naturaleza y papel en la formación, organización y funcionamiento de conglomerados humanos. Además, ofrece un examen de las implicaciones teóricas para la estabilidad social en axiomas antitéticos de estructura profunda, los cuales fragmentan una previa existencia social teleológica dentro de un arreglo de símbolos y rituales sociales fragmentarios lista parala cosificación. Y, a través de ello, se propone cómo el fenómeno contemporáneo de la globalización –y el paradigma económico neoclásico que lo sustenta—engendra un modelo de la realidad y del vivir idiosincrático basado en lo económico, modelo que no es ni una conceptualización humana comúnmente compartida, ni un objetivo universal deseado.
Chronotopic Juxtaposition in “Añejo cinco siglos”/Yuxtaposición cronotópica en “Añejo cinco siglos”
Authors: Parra Ericka
Published: February 2015

El tiempo y el espacio se interconectan en el cuento “Añejo cinco siglos” de la colección Apenas murmullos (2004). MaríaElena Llana (1936), la periodista y escritora cubana, utiliza una yuxtaposición a través del crono. La escritora trae al presentedos personajes femeninos de diferentes épocas. Una es la gallega Doña Isabel de Bobadilla (del tiempo pasado) y otraes la mulata Chabela (del tiempo presente). Ambos personajes femeninos tienen un diálogo que interconecta dos tiempos y espacios diferentes. Ellas crean intersecciones geográficas, políticas y personales, específicamente porque sus hombres han dejado la Habana bajo diferentes circunstancias pero con el mismo objetivo de establecerse en Florida. Don Hernando de Soto continúa la expedición española hacia tierra firme dejando a Isabel con el corazón roto mientras Lazarito ha salido en una balsa prometiéndole a Chabela que regresaría. Así, el propósito de este ensayo es demostrar que las diarias interconexiones personales son cronotopos que reconfiguran las condiciones ilegales de cruzar las fronteras geográficas e históricas. No obstante, en estas circunstancias personales ambas mujeres reconfiguran las narrativas del poder político y erótico.
The Construction of Characters in Roald Dahl´s Cinderella: A Systemic Functional Linguistic Analysis/La construcción de los personajes en “Cinderella” de ROALD DAHL: un análisis desde la Lingüística Sistémico Funcional
Authors: Rezzano Norma Susana
Published: February 2015

Los cuentos infantiles constituyen un recurso mediante el cual las culturas construyen y transmiten valores, que se expresan típicamente en los comportamientos de los personajes. En sus versiones publicadas bajo el título Revolting Rhymes (2008), el autor galés Roald Dahl desafía los valores transmitidos en algunos cuentos infantiles tradicionales. Este trabajo muestra la forma en que tal cuestionamiento se manifiesta en la construcción de los personajes de Cinderella de Dahl, mediante un análisis lingüístico Sistémico-Funcional (Halliday and Mathiessen 2004). Para ello, se exploran los patrones de transitividad en los que los personajes principales están involucrados y se realiza un análisis comparativo con una versión tradicional de este cuento. El análisis revela interesantes diferencias, especialmente en la construcción de los roles femeninos y masculinos.
Theoretical and methodological resources for the development of a line of educational policy research/Recursos teórico-metodológicos para el desarrollo de una línea de investigación sobre políticas públicas educativas
Authors: Graffe Gilberto
Published: February 2015

Se aborda el problema de las políticas públicas desde una perspectiva teórica y metodológica, con especial énfasis en el campo educativo. El interés se centra en brindar insumos a estudiantes y jóvenes investigadores de esta disciplina que permitan abordar con rigurosidad teórica y orientación metodológica, los asuntos relacionados con esta área de la educación a través del desarrollo de una línea de investigación. Se analizan los aportes conceptuales de autores expertos en el área y se exponen los criterios para identificar las fuentes institucionales y formales donde vienen expresadas de manera explícita dichas políticas; así como lo elementos metodológicos fundamentales para poder analizar la políticas públicas educativas a partir del examen de las gestiones de gobiernos.
What motivates non-traditional students to choose social work as a major/profession?/¿Qué motiva a los estudiantes mayores a seleccionar el trabajo social como Carrera universitaria/profesión?
Authors: Mutepa Raphael
Published: February 2015

Los estudiantes mayores [llamados no tradicionales en los Estados Unidos] forman parte de una población estudiantil universitaria encrecimiento, sin embargo, nuestra apreciación de los factores singulares que los motivan a escoger el trabajo social como carrera no haaumentado. En este estudio cualitativo, se entrevistó a 26 estudiantes mayores –los cuales asistían a una universidad estatal pequeña—sobre su decisión de escoger el trabajo social como carrera y profesión después de graduarse. Los resultados indican que las experienciasvarían entre los participantes. Los estudiantes mayores experimentaron distintos niveles de motivación, integración a la vida de laciudadela universitaria y participación en actividades sociales cuando se los comparó con los estudiantes jóvenes típicos. En general losestudiantes declararon que ingresaban a trabajo social para servir a los marginados, y también se refirieron a una red de apoyo socialque constaba de la familia, compañeros y apoyo institucional, lo cual incrementó las posibilidades al éxito de completar los requisitosde graduación, aunque estas redes no siempre estaban disponibles a la mayoría de los estudiantes mayores que fueron entrevistados eneste informe. El aula ofreció una luz de esperanza para la participación de los estudiantes mayores, una oportunidad para fortalecer suidentidad y para establecer conexiones entre los múltiples mundos donde residen dichos estudiantes. Las implicaciones de este estudiomuestran la importancia de reconocer las necesidades de los estudiantes mayores, así como también de dotarlos de un sistema de apoyoque les permita una experiencia universitaria más placentera.