bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Single Vacuum Furnace Design for Cosmogenic 3He Dating
Authors: Zimmermann Laurent , Blard Pierre Henri , Burnard Pete , Medynski Sarah , Pik Raphael , Puchol Nicolas
Published: January 2012

Helium‐3 is a stable cosmogenic isotope that can be used to determine the time interval during which a rock sample has been at or close to the Earth’s surface. As a result of the high production rate of ‘cosmogenic’3He (≈ 130 at g−1 year−1) and the low detection limit of modern mass spectrometers, it is possible to date exceptionally young surfaces (≈ 1000 years). The precision and accuracy of cosmogenic 3He measurements depend critically on the passive helium blank (produced by the metalwork of the extraction furnace) which can be significant relative to the sample signals. We have developed and constructed, at the CRPG (Nancy, France), a new high temperature furnace (< 1500 °C) to extract helium in minerals such as apatite, pyroxene and olivine at 1050, 1350 and 1450 °C, respectively. The furnace demonstrated an excellent helium extraction yield (> 99% for olivine and pyroxene for heating times of 20–30 min and temperatures in the range 1050–1450 °C) and low residual helium contributions (the blank, obtained under the same analytical conditions as for sample extraction: 1 × 10−15 mole 4He and < 4 × 10−21 mole 3He). This is approximately an order of magnitude lower than those reported by other laboratories using conventional furnaces.
What Is STEM? A Discussion About Conceptions of STEM in Education and Partnerships
Authors: Breiner Jonathan M. , Harkness Shelly Sheats , Johnson Carla C. , Koehler Catherine M.
Published: January 2012

Educational reformation has proceeded slowly despite the many calls to improve science and mathematics for our students. The acronym STEM (science, technology, engineering, and mathematics) has been adopted by numerous programs as an important focus for renewed global competitiveness for the United States, but conceptions of what STEM entails often vary among stakeholders. This paper examines the conceptions of STEM held by faculty members from a public Research I institution in the middle of a regional “STEM movement.” Faculty members responded to two open‐ended questions: (1) What is STEM? and (2) How does STEM influence and/or impact your life? Although 72% of these faculty members possessed a relevant conception of STEM, the results suggest that they do not share a common conceptualization of STEM. Their conception is most likely based on their academic discipline or how STEM impacts their daily lives. STEM faculty members were likely to have a neutral or positive conception where non‐STEM faculty members often had negative feelings about STEM.
Implementation of STEM Education Policy: Challenges, Progress, and Lessons Learned
Authors: Johnson Carla C.
Published: January 2012

This is a case study of the implementation of state STEM (science, technology, engineering, and mathematics) policy over the period of the first 18 months of building a regional STEM partnership. Fullan's change theory is the framework used to determine progress and associated challenges with building a regional STEM educational partnership and establishment of STEM schools through a sustained education reform effort. Key stakeholders who were involved in leading this effort participated in focus groups, as well as individual interviews. Archival documentation was also used. Findings indicate implementation of STEM policy in this state experienced some barriers because of the nature of funding and timeline, as well as the competing agendas and interests of partners who did not have the opportunity to develop common vision and strategic plans prior to implementation. Implications for STEM policy decisions and implementation of other efforts through Race to the Top and other federal funding sources are discussed.
Is Adding the E Enough? Investigating the Impact of K‐12 Engineering Standards on the Implementation of STEM Integration
Authors: Roehrig Gillian H. , Moore Tamara J. , Wang Hui‐Hui , Park Mi Sun
Published: January 2012

The problems that we face in our ever‐changing, increasingly global society are multidisciplinary, and many require the integration of multiple science, technology, engineering, and mathematics (STEM) concepts to solve them. National calls for improvement of STEM education in the United States are driving changes in policy, particularly in academic standards. Research on STEM integration in K‐12 classrooms has not kept pace with the sweeping policy changes in STEM education. This study addresses the need for research to explore the translation of broad, national‐level policy statements regarding STEM education and integration to state‐level policies and implementation in K‐12 classrooms. An interpretive multicase study design was employed to conduct an in‐depth investigation of secondary STEM teachers' implementation of STEM integration in their classrooms during a yearlong professional development program. The interpretive approach was used because it provides holistic descriptions and explanations for the particular phenomenon, in this case STEM integration. The results of this study demonstrate the possibilities of policies that use state standards documents as a mechanism to integrate engineering into science standards. Our cases suggest that STEM integration can be implemented most successfully when mathematics and science teachers work together both in a single classroom (co‐teaching) and in multiple classrooms (content teaching—common theme).
Learning for STEM Literacy: STEM Literacy for Learning
Authors: Zollman Alan
Published: January 2012

We are in the STEM generation whose comprehensive purpose is to resolve (1) societal needs for new technological and scientific advances; (2) economic needs for national security; and (3) personal needs to become a fulfilled, productive, knowledgeable citizen. STEM specifically refers to science, technology, engineering, and mathematics, but now has a broader meaning to include environment, economics, and medicine. Currently, there is not an agreement of the particulars in education, or in standards, by professional organizations that define STEM literacy. Most definitions do cover societal and economic needs but overlook personal needs. There is a general consensus that everyone needs to be STEM literate. But there is a difference between literacy and being literate. STEM literacy should not be viewed as a content area but as a deictic means (composed of skills, abilities, factual knowledge, procedures, concepts, and metacognitive capacities) to gain further learning. This paper gives a brief background of literacy definitions in STEM and presents a description of STEM literacy based upon (1) cognitive, (2) affective, and (3) psychomotor learning theory domains. The paper stresses the need to evolve from learning for STEM literacy to using STEM literacy for learning to satisfy our societal, economic, and personal needs.
Task complexity, student perceptions of vocabulary learning in EFL, and task performance
Authors: Wu Xiaoli , Lowyck Joost , Sercu Lies , Elen Jan
Published: January 2012

Background. The study deepened our understanding of how students’ self‐efficacy beliefs contribute to the context of teaching English as a foreign language in the framework of cognitive mediational paradigm at a fine‐tuned task‐specific level.

Aim. The aim was to examine the relationship among task complexity, self‐efficacy beliefs, domain‐related prior knowledge, learning strategy use, and task performance as they were applied to English vocabulary learning from reading tasks.

Sample. Participants were 120 second‐year university students (mean age 21) from a Chinese university.

Method. This experiment had two conditions (simple/complex). A vocabulary level test was first conducted to measure participants’ prior knowledge of English vocabulary. Participants were then randomly assigned to one of the learning tasks. Participants were administered task booklets together with the self‐efficacy scales, measures of learning strategy use, and post‐tests. Data obtained were submitted to multivariate analysis of variance (MANOVA) and path analysis.

Results. Results from the MANOVA model showed a significant effect of vocabulary level on self‐efficacy beliefs, learning strategy use, and task performance. Task complexity showed no significant effect; however, an interaction effect between vocabulary level and task complexity emerged. Results from the path analysis showed self‐efficacy beliefs had an indirect effect on performance. Our results highlighted the mediating role of self‐efficacy beliefs and learning strategy use.

Conclusions. Our findings indicate that students’ prior knowledge plays a crucial role on both self‐efficacy beliefs and task performance, and the predictive power of self‐efficacy on task performance may lie in its association with learning strategy use.
University and student segmentation: Multilevel latent‐class analysis of students’ attitudes towards research methods and statistics
Authors: Mutz Rüdiger , Daniel Hans‐Dieter
Published: January 2012

Background. It is often claimed that psychology students’ attitudes towards research methods and statistics affect course enrolment, persistence, achievement, and course climate. However, the inter‐institutional variability has been widely neglected in the research on students’ attitudes towards research methods and statistics, but it is important for didactic purposes (heterogeneity of the student population).

Aims. The paper presents a scale based on findings of the social psychology of attitudes (polar and emotion‐based concept) in conjunction with a method for capturing beginning university students’ attitudes towards research methods and statistics and identifying the proportion of students having positive attitudes at the institutional level.

Sample. The study based on a re‐analysis of a nationwide survey in Germany in August 2000 of all psychology students that enrolled in fall 1999/2000 (N= 1,490) and N= 44 universities.

Methods. Using multilevel latent‐class analysis (MLLCA), the aim was to group students in different student attitude types and at the same time to obtain university segments based on the incidences of the different student attitude types.

Results. Four student latent clusters were found that can be ranked on a bipolar attitude dimension. Membership in a cluster was predicted by age, grade point average (GPA) on school‐leaving exam, and personality traits. In addition, two university segments were found: universities with an average proportion of students with positive attitudes and universities with a high proportion of students with positive attitudes (excellent segment).

Conclusions. As psychology students make up a very heterogeneous group, the use of multiple learning activities as opposed to the classical lecture course is required.
Impact of Manufacturing Variability and Nonaxisymmetry on High-Pressure Compressor Stage Performance
Authors: Lange Alexander , Voigt Matthias , Vogeler Konrad , Schrapp Henner , Johann Erik , Gümmer Volker
Published: January 2012

This paper introduces an approach for considering manufacturing variability leading to a nonaxisymmetric blading in the computational fluid dynamics simulation of a high-pressure compressor stage. A set of 150 rotor blades from a high-pressure compressor stage was 3D scanned in order to obtain the manufacturing variability. The obtained point clouds were parameterized using a parametric blade model, which uses typical profile parameters to translate the geometric variability into a numerical model. Probabilistic simulation methods allow for the generation of a sampled set of blades that statistically corresponds to the measured one. This technique was applied to generate 4000 sampled blades in order to investigate the influence of a nonaxisymmetric blading. It was found that the aerodynamic performance is considerably influenced by a variation of the passage cross section. Nevertheless, this influence decreases with an increasing number of independently sampled blades and, thus, independently shaped passage cross sections. Due to its more accurate consideration of the geometric variability, the presented methodology allows for a more realistic performance analysis of a high-pressure compressor stage.
Illness as a condition of our existence in the world: on illness and pathic existence
Authors: Martinsen Elin Håkonsen , Solbakk Jan Helge
Published: January 2012

This paper seeks to find different ways of addressing illness as an experience essential to the understanding of being a human being. As a conceptual point of departure, we suggest the notion of ‘pathic existence’ as developed by the German physician and philosopher Viktor von Weizsäcker (1886–1957). Through an analysis of his conceptualisation of the pathic and of pathic categories, we demonstrate how this auxiliary typology may be of help in unveiling different modes of ill-being, orKranksein. Furthermore, we show how illness plays a paradigmatic role in this type of existence. We discuss how von Weizsäcker's claim of illness as “a way of being human” indicates how such a view of the illness existence both differs from and touches upon other streams of thought within the philosophy of medicine and medical ethics. Finally, we highlight some of the normative implications emerging from this perspective of relevance in today's medicine.
Pial arteriovenous fistulae in pediatric patients: associated syndromes and treatment outcome
Authors: Walcott Brian P , Smith Edward R , Scott R Michael , Orbach Darren B
Published: January 2012

Objective

Pediatric pial arteriovenous fistulae (pAVF) are rare vascular lesions of the CNS, reported to have up to a 25% association with hereditary hemorrhagic telangiectasia. The presentation, treatment and syndromes associated with pAVF in children are reported here.

Design

A pediatric database for pAVF was retrospectively reviewed. Patients with carotid–cavernous fistulae, dural arteriovenous fistulae, brain arteriovenous malformations and vein of Galen malformations were excluded. Radiographic outcome was assessed using digital subtraction angiography, and clinical outcome by the Functional Status Scale (6=normal, maximal incapacity=30).

Results

Between July 2003 and June 2011, seven patients with pAVF (six intracranial and one spinal) were treated. Mean age was 4.2 years. The most common clinical presentation was high output cardiac failure (43%). Two patients (29%) harbored a known mutation in the RASA1 gene, associated with a hereditary vascular syndrome: capillary malformation–arteriovenous malformation. No patient had hereditary hemorrhagic telangiectasia. Treatment resulted in complete lesional obliteration in six of seven patients, with treatment ongoing in the seventh. Five of seven patients had combined endovascular and surgical treatment while two underwent endovascular embolization alone. Functional Status Scale scores at the most recent follow-up were 6 in all but one patient who had presented with a pretreatment hemianopsia.

Conclusion

Treatment is effective in obliterating pAVF in children, with an excellent prognosis seen in our cohort. Genetic screening is indicated, with capillary malformation–arteriovenous malformation being the most frequently seen syndrome. No patients had hemorrhagic hereditary telangiectasia.
Dural arteriovenous fistulae in pediatric patients: associated conditions and treatment outcomes
Authors: Walcott Brian P , Smith Edward R , Scott R Michael , Orbach Darren B
Published: January 2012

Objective

Dural arteriovenous fistulae (dAVF) are rare vascular lesions of the CNS with potentially significant morbidity and mortality. Our experience in the treatment of children with dAVF is reported.

Design

Our neurosurgical and neurointerventional pediatric database was retrospectively reviewed for patients with dAVF. Brain arteriovenous malformations, pial fistulae, vein of Galen malformations and extracranial fistulae were excluded. Angiography was used to assess radiographic outcome in all cases. Clinical outcome was assessed by the pediatric Functional Status Scale (6=normal, maximal incapacity=30).

Results

Between July 2003 and June 2011, seven patients with dAVF were treated, with a mean age at presentation of 4.8 years. Presenting symptoms included facial venous prominence, headache, macrocephaly and symptoms of elevated intracranial pressure; one patient (14%) had asymptomatic dAVF discovered on imaging follow-up after craniotomy for cavernous malformation. Two cases (28%) were associated with vascular anomaly syndromes, PHACE association and PTEN associated syndrome. Venous sinus thrombosis was identified in four patients (57%) and was associated with a systemic hypercoagulable state or trauma. Complete obliteration was achieved in six of seven patients. Treatment was exclusively endovascular in six patients and by combined surgical/endovascular means in the remaining patient. No treatment complications were experienced. Functional Status Scale scores at an average of 2 years of follow-up were 6 in all patients.

Conclusion

Treatment is effective in the obliteration of dAVF in children and is well tolerated, with patients having excellent prognoses. Genetic screening and hypercoagulable workup are indicated, particularly when other anomalies or sinus thrombosis coexist.
The cost and cost-effectiveness of opportunistic screening forChlamydia trachomatisin Ireland
Authors: Gillespie Paddy , O'Neill Ciaran , Adams Elisabeth , Turner Katherine , O'Donovan Diarmuid , Brugha Ruairi , Vaughan Deirdre , O'Connell Emer , Cormican Martin , Balfe Myles , Coleman Claire , Fitzgerald Margaret , Fleming Catherine
Published: January 2012

Objective

The objective of this study was to estimate the cost and cost-effectiveness of opportunistic screening forChlamydia trachomatisin Ireland.

Methods

Prospective cost analysis of an opportunistic screening programme delivered jointly in three types of healthcare facility in Ireland. Incremental cost-effectiveness analysis was performed using an existing dynamic modelling framework to compare screening to a control of no organised screening. A healthcare provider perspective was adopted with respect to costs and included the costs of screening and the costs of complications arising from untreated infection. Two outcome measures were examined: major outcomes averted, comprising cases of pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility in women, neonatal conjunctivitis and pneumonia, and epididymitis in men; and quality-adjusted life-years (QALY) gained. Uncertainty was explored using sensitivity analyses and cost-effectiveness acceptability curves.

Results

The average cost per component of screening was estimated at €26 per offer, €66 per negative case, €152 per positive case and €74 per partner notified and treated. The modelled screening scenario was projected to be more effective and more costly than the control strategy. The incremental cost per major outcomes averted was €6093, and the incremental cost per QALY gained was €94 717. For cost-effectiveness threshold values of €45 000 per QALY gained and lower, the probability of the screening being cost effective was estimated at <1%.

Conclusions

An opportunistic chlamydia screening programme, as modelled in this study, would be expensive to implement nationally and is unlikely to be judged cost effective by policy makers in Ireland.
Structural Steel Performance Following Severe Earthquake Loading
Authors: Fergusona W. G. , Seal C. K. , Hodgson M. A. , Clifton G. C.
Published: January 2012

The second Christchurch earthquake on February 22, 2011, Magnitude 6.35, generated more intense shaking in the Central Business District than the September 4, 2010 Darfield earthquake, Magnitude 7.1. The second earthquake was closer to the CBD and at shallow depth, resulting in peak ground accelerations 3 times higher. There was significant failure of unreinforced masonry buildings and collapse of a few reinforced concrete buildings, leading to loss of life. Steel structures on the whole performed well during the earthquake and the plastic, inelastic deformation was less than expected given the strength of the recorded ground accelerations. For steel buildings designed to withstand earthquake loading, a design philosophy is to have some structural elements deform plastically, absorbing energy in the process. Typically elements of beams are designed to plastically deform while the columns remain elastic. In the earthquake some of these elements deformed plastically and the buildings were structurally undamaged. The question which then arises is; the building may be safe, but will it withstand a further severe earthquake? In other words how much further plastic work damage can be absorbed without failure of the structural element? Previous research at Auckland on modern structural steel, where the steel was prestrained various levels, to represent earthquake loading, the toughness was determined, as a function of prestrain for the naturally strain-aged steel. Further research, on the same steel, investigated life to failure for cyclic plastic straining in tension and compression loading at various plastic strain amplitudes. This work has shown that provided the plastic strain in the structural element is in the range 2 – 5% the steel will still meet the relevant NZ Standards. To determine the remaining life the plastic strain must be determ ined then the decision made; to use the building as is, replace the structural element or demolish.
SITE OCCUPANCIES OF NITRIDE AND OXIDE IONS IN STRONTIUM NIOBIUM OXYNITRIDE PEROVSKITES
Authors: Komiyama T. , Masubuchi Y. , Motohashi T. , Kikkawa S.
Published: January 2012

Crystal structure was refined on Sr - Nb and Sr ( La )- Nb oxynitride perovskites prepared through citrate route by using neutron diffraction. The former had the composition of SrNbO2.11N0.89and crystallized in I4/mcm with a = 0.57099(2) nm , c = 0.81015(5) nm having excess oxide ions in apical 4a site around Nb being compared to the cis- TaO4N2octahedra in SrTaO2N . The latter crystallized in the same space group with Sr0.81La0.19having a = 0.57126(3) nm , c = 0.81055(6) nm . It was assumed that Sr0.81La0.19O1.90N1.10has similar O/N occupancy in both apical 4a and equatorial 8h sites. The La substitution made the O/N occupancies equilibrated around Nb . The niobium valency was slightly less than five in these oxynitride perovskites.
IN SITU HIGH TEMPERATURE FT-IR STUDY OF THE INTERLAYER NAPHTHALENE-2,6-DISULFONATE IN Mg AND Al LAYERED DOUBLE HYDROXIDE
Authors: KANEZAKI EIJI , KATOH MASAHIRO
Published: January 2012

In high temperature in situ FT-IR (HTFTIR) spectra of Mg and Al layered double hydroxide with interlayer naphthalene-2,6-disulfonate ( Mg / Al / N 26 DS - LDH ), one S - O stretching vibration band of the non-coordinating - SO 3 group in the interlayer N 26 DS dianion is observed below 400 °C at 1035 cm-1 with keeping intensity. High temperature in situ X-ray diffraction (HTXRD) indicates that the basal spacing remains also constant up to 400 °C, MgSO 4 appears after the LDH collapses at 500 °C and some metal oxides are formed at higher temperature. Both results in HTXRD and HTFTIR indicate that the layered structure in this LDH is stable against heating up to 400 °C.
NITROGEN DIOXIDE GAS SENSOR BASED ON COBALT AND NICKEL PHTHALOCYANINE WORKING AT ROOM TEMPERATURE
Authors: DATIR A. M. , GHOLE V. S. , KOINKAR PANKAJ , CHAKANE S. D.
Published: January 2012

Cobalt and Nickel Phthalocyanines ( CoPc , NiPc ) were synthesised by chemical route. Phthalocyanines (Pcs) were characterized by different techniques such as, XRD, UV Visible, and FTIR. Samples in the pellet form were prepared for gas sensing applications. The effect of NO 2 at different concentrations in air at room temperature on the electrical conductivity of CoPc and NiPc has been studied. Sensitivity, response time and recovery time of sensors for different NO 2 concentrations were studied. The comparison of these materials as NO 2 gas sensor is discussed in this research paper.
SEMI-EMPIRICAL KERNEL FUNCTION FOR THE ANALYSIS OF FIBER BRAGG GRATINGS UNDER TEMPERATURE DISTRIBUTIONS
Authors: BAE JINHO , LEE CHONG HYUN , KIM JOON-YOUNG , KIM YUN-HAE
Published: January 2012

To analyze the various Fiber Bragg gratings (FBGs) with thermal changes, we present how makes a kernel function to translate the information of thermal change into coupling coefficient and detuning factor. We also propose an accurate and versatile extended fundamental matrix model (EFMM) with the kernel function. The proposed model is then can be used to design the piecewise uniform FBGs with the thermal changes. Sensitivity of a temperature variation is performed using Mote Carlo simulations.
R&D OF SICF/SIC COMPOSITE FOR FUSION REACTOR MATERIAL
Authors: YOON HAN-KI , CHO HO-JUN , KOHYAMA AKIRA , NODA TETSUJI
Published: January 2012

During the operation of a fusion reactor, a certain type of transients could induce rapid cooldown of the reactor with relatively high or increasing system pressure. This induces a high tensile stress at the inner surface of the blanket, which is called the thermal shock. Test Blanket Module (TBM) has been designed to account for the performance of DEMO-relevant blanket. But, the TBM uses helium as coolant and tritium as purge gas, and FM steel, SiC f / SiC composites as a structural material. The SiC f / SiC composites with a SiC sub-layer/ PyC interlayers were therefore fabricated in order to improve the oxidation resistance. In the refractory field SiC f / SiC composites need to investigate residual stress and thermal shock behavior when high chemical stability and corrosion resistance are necessary.

In this study, SiC f / SiC composite were fabricated by NITE process and the chemical vapor infiltration (CVI) method. SiC f / SiC composites have been examined and the detail analyses of the microstructure and the mechanical strength were conducted. Various pyrolytic carbons ( PyC ) with SiC interlayer coatings were applied to the composites for improvement of the mechanical properties at the interface.
SELF HEALING POTENTIAL OF GREEN NANOCOMPOSITES FROM CRYSTALLINE CELLULOSE
Authors: PANDEY JITENDRA KUMAR , TAKAGI HITOSHI
Published: January 2012

In plant cell walls, stiff semicrystalline nano dimensional cellulose microfibrils are embedded in a pliable amorphous matrix where the size and shape of the cellulose fibrils are controlled by the dimensions of crystalline regions, providing them a unique structural and physical combination to be applied as load-bearing constituent in composites. The qualities such as specific orientation under magnetic field, extraction through simple process, abundantly available source from nature and desirable modifications have deliberately directed the intense research efforts in a number of disciplines ranging from commodity to higher applications, not only in the area of high performance polymer based composites but also to develop biosensors, magnetic strips and optical devices. The present work is focused on the use of cellulose nano-fillers for creating the self-healing function and their effect on material properties of resulting composites. The present work is in initial stage and reviews the use of cellulose nano-fillers for creating the self-healing function and their effect on material properties of resulting composites.
NONLINEAR ULTRASONIC CHARACTERIZATION OF FATIGUE DAMAGE IN SUS316L ALLOY
Authors: KIM CHUNGSEOK , CHOI SUNGHO , JHANG KYUNGYOUNG , HYUN CHANGYONG
Published: January 2012

This paper presents an oblique incidence technique for characterizing the ultrasonic nonlinearity of a stainless steel 316L alloy subjected to high-cycle fatigue testing. A rectangular hourglass-shaped specimen was prepared, and various fatigue-driven deformations were accumulated at several positions near the middle of the specimen. These locations were chosen to correspond to areas likely to exhibit stress concentration responses resulting in slip and dislocation evolution. The nonlinearity increased significantly near the center of the specimen and thus was strongly correlated with fatigue damage. An oblique incidence technique using longitudinal waveforms is a potentially viable method for characterizing the high-cycle fatigue deformation of 316L alloys.
THE FRICTION BEHAVIOR OF NBR SURFACE MODIFIED BY ARGON PLASMA TREATMENT
Authors: KIM JONG-HYOUNG , KIM SEOCK-SAM , CHOI SI-GEUN , LEE SEUNG-HUN
Published: January 2012

Different treatment time and bias voltage with RF Ar plasma were used to improve tribological properties of NBR (Nitrile Butadiene Rubber). Chemical structure analyses of NBR by Attenuated Total Reflectance (ATR) were performed to clarify the functionality modification after the plasma treatment. In addition, wetting experiments were carried out by measuring the contact angle of distilled water drops on the NBR surface. ATR analysis revealed that the number of - C = O , - C - O , O - H functional groups increased after the argon plasma treatment. The functional groups led to changes in the contact angle from 100 to 50 degrees. The results showed that form-like nanostructures on the NBR was observed at the bias voltage of -400 V. The friction test showed that coefficient of friction after modified NBR in lubricated condition decreased from 0.25 to 0.15 with the increasing bias voltage due to the surface structure formations and better bonding with grease lubricant.
STUDY ON THE TRIBOLOGICAL BEHAVIOR OF CUTTING TOOLS COATED WITH FILMS
Authors: YASUOKA MANABU
Published: January 2012

A hard film coat can improve a tool's performance. In this study, the frictional properties of an uncoated tool and a coated tool with TiN were measured against that of SCM440 (42 CrMo 4) steel. The results showed there was no significant difference between the friction coefficient of the high-speed steel tool and the tool coated with TiN but the friction coefficient of uncoated tool was slightly lower than that of the steel. In the second part of the study, coats of TiN , TiC , CrN , and TiAlN were deposited on high-speed steel and the wear characteristics were determined with a pin-on-disk wear examination. The differences in the friction coefficients were attributed to the difference in the wear of the slipping material. There were large differences in the adhesion characteristics on the surface of the slipping material. The author suggest that these differences influence the characteristics of the cutting tool.
A STUDY ON JOINING TECHNOLOGY OF ALUMINUM ALLOY SHEET USING NANO-ADHESIVES
Authors: LIU ZEMIN , BAE DONG HO
Published: January 2012

In this paper, a new nano-adhesive which has been improved the conventional epoxy resin that is widely used in the automobile industries was introduced. Multi-walled carbon nano-tubes (MWCNTs) (1%-3% by weight) were mixed into epoxy resin using a mixer. The bubbles generated during the mixing processes were removed using a high vacuum. In order to optimize the quality and performance for actual application, the mechanical properties of the joints taking into account the geometrical parameters of bonded layer were basically assessed. From the results, both the static tensile strength and fatigue strength increased dramatically at a carbon nano-tube weight percentage of 2% compared to other values. The surface treatment condition of the plates also affected the tensile strength of the nano-adhesive bonded joints.
BLUNTNESS MEASUREMENT OF A BERKOVICH INDENTER
Authors: LEE YUN-HEE , YOO BYUNG-GIL , JANG JAE-IL
Published: January 2012

Indenter blunting is inevitable in nanoindentations and results in unexpected contact properties. Both relaxation of the indentation size effects and deepening of the substrate effects under a blunted indenter cause a change of the bathtub-shaped hardness with indentation depth in a soft film on hard substrate. Thus an identification of three-dimensional morphology of an indenter apex is necessary for precise measurements of hardness in thin films. We observed an actual Berkovich indenter using an atomic force microscope (AFM). Through a quantitative analysis on the AFM image, data pairs of contact area versus contact depth were obtained; curvature radius of the apex was estimated by searching a sphere well-fitted to the indenter apex morphology. The estimated curvature radius and blunted height were 1043.9±50.9 nm and 44.4 nm, respectively. By comparing with the result from the modified Kick's law, both blunted heights were comparable each other within a 7 nm difference. This confirms validity of the direct observation method with the AFM.
ESTIMATION OF DEFORMABILITY OF FRESH CONCRETE MIXED WITH FLY ASH FLOWING THROUGH TAPERED PIPE USING PUMPING TESTER
Authors: YAMAJI NORITSUGU , HASHIMOTO CHIKANORI , WATANABE TAKESHI , ISHIMARU KEISUKE
Published: January 2012

In study, we quantitatively evaluate and compare high-viscosity concrete with type fourth fly ash and normal concrete. We estimate the deformability of fresh concrete using a pumping tester and investigate the pumpability of concrete. In this study, the range of stable pumping is evaluated by having the average pump oil pressure and the coefficient of variation of the oil pressure. At an average pump oil pressure of less than 0.50 MPa and coefficient of variation of less than 15 %, the range of steady pumping of fly ash concrete and normal concrete are different. Concrete with type fourth fly ash significantly decreases the coefficient of variation of the oil pressure and prevents the stoppage of fresh concrete flowing in pipe.
DEVELOPMENT OF SIMPLE FREEZING AND THAWING TEST USING LIQUID NITROGEN
Authors: HASHIMOTO SHIN-ICHIRO , EMOTO YUKIO , SOEDA MASASHI , HAZEHARA HIROTAKA , HASHIMOTO CHIKANORI
Published: January 2012

In this research, an apparatus for a simple freezing and thawing test using liquid nitrogen that enables measurement to be carried out even in actual structures has been developed based on existing research studies as a new testing method replacing the freezing and thawing test of concrete defined in the Japanese Industrial Standards (JIS), and a reviews was made of its practicality. The results indicated that, when used in conjunction with ultrasonic measurement equipment, the apparatus for a simple freezing and thawing test using liquid nitrogen was capable of evaluating the degradation of concrete surfaces part after only a small number of cycles and was greatly effective in practical application.
EVALUATION OF SELF HEALING EFFECT IN FLY-ASH CONCRETE BY ULTRASONIC TEST METHOD
Authors: WATANABE TAKESHI , FUJIWARA YUKI , HASHIMOTO CHIKANORI , ISHIMARU KEISUKE
Published: January 2012

Self-healing effect is widely known in concrete. It was reported that concrete with fly ash has self healing effect against freezing and thawing damage. Fly ash is one of the popular admixtures as a waste material from coal fired power plant. In this study, main purpose is to evaluate self healing effect of fly ash concrete by ultrasonic test method. In experiment, fly ash replaced 5 and 15 % of unit sand content. To damage fly ash concrete specimens, one of the freezing and thawing test produced by our laboratory were performed. After the test, the fly-ash concrete specimens are cured by water and performed ultrasonic test. In the ultrasonic test, wave forms are detected and wave velocity and ratio of relative dynamic modulus of elasticity are calculated. It is widely known that wave velocity of damaged concrete is slower than sound concrete and dynamic modulus is used for evaluate of damage. As a result, it is recognized that these fly-ash concrete specimens has self healing effect. In addition, in order to investigate curing effect of concrete against freezing and thawing damage, ultrasonic test method is powerful method of nondestructive test.
DYNAMIC MODELING AND STRUCTURAL ANALYSIS OF MANTA-TYPE UUV
Authors: KIM JOON-YOUNG , KIM YUN-HAE , CHOI HYEUNG-SIK , BAE JINHO , LEE CHONG HYUN , CHO IL-HYOUNG , KOH HYEOK-JUN
Published: January 2012

This paper describes the dynamic modeling, structural analysis, implementation and experimental test of a Manta-type Unmanned Underwater Vehicle (MUUV). Various controllers such as PID, Sliding mode, and Fuzzy and H∞ controllers are designed for depth and heading control in order to compare the performance of each controller based on simulation. In addition, experimental tests are carried out in a towing tank for depth keeping and heading angle tracking.
TENSOR-BASED FEATURE REPRESENTATION WITH APPLICATION TO MULTIMODAL FACE RECOGNITION
Authors: YU HONGCHUAN , ZHANG JIAN J. , YANG XIAOSONG
Published: January 2012

In this paper, a novel feature representation to multimodal face recognition is proposed, which possesses three properties: completeness, robustness and compactness. This feature descriptor allows all information of an object to be reproduced and its representation is invariant to rigid motion. In order to effectively take advantage of the proposed feature descriptor, we amend our previous ND-PCA scheme with multidirectional decomposition technique, and provide the estimation of the upper bound error of the amended classifier. It is proved to be linear optimal compared to other linear classifiers. To investigate the numerical performance of the presented feature descriptor, we apply it to both multiple modal and single modal samples, and the revised ND-PCA classifier is performed on the resulting feature representations. The experiments of verification and identification are carried out on two different gallery-probe face databases in order for the results to be evaluated by ROC and CMC curves independently.
A STUDY OF CHAOTIC PHENOMENA IN HUMAN-LIKE REACHING MOVEMENTS
Authors: RAHATABAD FEREYDOON NOWSHIRAVAN , FALLAH ALI , JAFARI AMIR HOMAYOUN
Published: January 2012

In this paper, the feasibility of observing chaotic behavior in the model of a human arm is discussed. Two-Link Arm driven by Six Muscles (TLASM) which is a well-known model of planar human arm reaching movements in the horizontal plane is investigated. Reinforcement learning (RL) that is considered as a model for Dopamine-based learning in the brain is used to control the TLSAM. Finally, the existence of chaos phenomena in the TLASM model controlled with RL is researched using tools like bifurcation maps, Lyapunov exponents, phase-plane trajectories, and spectral analysis using FFT. Results yield that chaos phenomena may occur in the overall system by changing some internal parameters of muscles that have a physiological explanation.
CHAOTIFICATION OF NONAUTONOMOUS DISCRETE DYNAMICAL SYSTEMS
Authors: HUANG QIULING , SHI YUMING , ZHANG LIJUAN
Published: January 2012

This paper focuses on the chaotification of nonautonomous discrete dynamical systems in finite-dimensional and general Banach spaces by feedback control techniques. Several chaotification schemes with general controllers and sawtooth function are established, respectively, where the controllers are time-invariant. The controlled systems are proved to be chaotic in the strong sense of Li–Yorke.
ON THE GLOBAL BOUNDEDNESS OF THE CHEN SYSTEM
Authors: BARBOZA RUY , CHEN GUANRONG
Published: January 2012

This paper provides a complete proof of the global boundedness of the Chen system, and some characterization of its trapping region.
PHYSICS FROM EXTRA DIMENSIONS: MASS HIERARCHIES AND EXPERIMENTAL PREDICTIONS
Authors: ANTONIADIS IGNATIOS
Published: January 2012

Lowering the string scale in the TeV region provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal dimensions, in the sub-millimeter region, and transverse to a braneworld where our universe must be confined. I review the main properties of this scenario and its experimental implications.
THE EVOLUTION OF THE BARYON DISTRIBUTION IN THE UNIVERSE FROM COSMOLOGICAL SIMULATIONS
Authors: DURIER FABRICE , DE FREITAS PACHECO JOSÉ A.
Published: January 2012

The evolution of the baryon distribution in different phases, derived from cosmological simulations, are here reported. These computations indicate that presently most of baryons are in a warm-hot intergalactic (WHIM) medium (about 43%) while at z = 2.5 most of baryons constitute the diffuse medium (about 74%). Stars and the cold gas in galaxies represent only 14% of the baryons at z = 0. For z < 4 about a half of the metals are locked into stars while the fraction present in the WHIM and in the diffuse medium increases with a decreasing redshift. In the redshift range 0 ≤ z ≤ 2.5, the amount of metals in the WHIM increases from 4% to 22% while in the diffuse medium it increases from 0.6% to 4%. This enrichment process is due essentially to a turbulent diffusion mechanism associated to mass motions driven by supernova explosions. At z = 0, simulated blue (late type) galaxies show a correlation of the oxygen abundance present in the cold gas with the luminosity of the considered galaxy that agrees quite well with data derived from HII regions.
NEUTRINOS AND THE MATTER-ANTIMATTER ASYMMETRY IN THE UNIVERSE
Authors: FELIPE RICARDO GONZÁLEZ
Published: January 2012

The discovery of neutrino oscillations provides a solid evidence for nonzero neutrino masses and leptonic mixing. The fact that neutrino masses are so tiny constitutes a puzzling problem in particle physics. From the theoretical viewpoint, the smallness of neutrino masses can be elegantly explained through the seesaw mechanism. Another challenging issue for particle physics and cosmology is the explanation of the matter-antimatter asymmetry observed in Nature. Among the viable mechanisms, leptogenesis is a simple and well-motivated framework. In this paper we briefly review these aspects, making emphasis on the possibility of linking neutrino physics to the cosmological baryon asymmetry originated from leptogenesis.
DELTA GRAVITY AND THE ACCELERATED EXPANSION OF THE UNIVERSE
Authors: ALFARO JORGE
Published: January 2012

We study a model of the gravitational field based on two symmetric tensors. The equations of motion of test particles are derived. We explain how the Equivalence principle is recovered. Outside matter, the predictions of the model coincide exactly with General Relativity, so all classical tests are satisfied. In Cosmology, we get accelerated expansion without a cosmological constant.
GAUSS-BONNET CONTRIBUTIONS TO THE ENTROPY OF EXTREMAL BLACK HOLES IN THE GAUGE-GRAVITY SECTOR
Authors: ULACIA REY ALAIN
Published: January 2012

Using the Sen's mechanism we calculate the entropy for an AdS2 × Sd-2 extremal and static black hole in four dimensions, with higher derivative terms that comes from a three parameter non-minimal Einstein-Maxwell theory. The explicit results for Gauss-Bonnet in the gauge-gravity sector are shown.
ON THE GEOMETRIC EFFECT OF DARK MATTER
Authors: CAPISTRANO ABRAÃO J. S. , ODON PEDRO I. , CABRAL LUIS A.
Published: January 2012

We study the effect of the extrinsic curvature on the rotation curves within the context of brane-world, in a 5-d bulk with constant curvature. The covariant equations of motion for the brane-world are applied to determine the modified Newtonian potential approximation and the velocity curve. We consider a static disk galaxy which is composed only of ordinary visible matter. Using the Weyl static metric as a model, we find that the velocity curve is given by the square root of a small power of the radial distance to the galactic core.
DARK MATTER SEARCH AND THE SCALAR QUARK CONTENTS OF THE NUCLEON
Authors: DINTER SIMON , DRACH VINCENT , JANSEN KARL
Published: January 2012

We present lattice QCD simulation results from the European Twisted Mass Collaboration (ETMC) for the light, strange and charm quark contents of the nucleon. These quantities are important ingredients to estimate the cross-section for the detection of WIMPs as Dark Matter candidates. By employing a particular lattice QCD formulation, i.e. twisted mass fermions, accurate results of the light and strange scalar contents of the nucleon can be obtained. In addition, we provide a bound for the charm quark content of the nucleon.
EFFECTS OF GALACTIC GAMMA RAY BURSTS ON PLANETARY BIOSPHERES
Authors: CÁRDENAS ROLANDO , MARTÍN OSMEL , PEÑATE LIUBA , HORVATH JORGE
Published: January 2012

We examine the short-term effects that a galactic Gamma Ray Burst would cause on a planetary biosphere. The immediate environmental perturbation would arise due to the emission of an aurora like spectrum in the middle and low atmosphere, delivering at planet's surface a brief but intense ultraviolet flash. We calculated potential damages to both the photosynthetic and DNA apparatuses of unicellular organisms. We conclude that if the progenitor is 1-2 kiloparsec distant in the Milky Way, its main short-term bio-effect will be radiation damage in the photosynthetic machinery rather than in the genome.
TOWARDS A RELATIVISTIC THOMAS-FERMI THEORY OF WHITE DWARFS AND NEUTRON STARS
Authors: RUEDA JORGE A. , RUFFINI REMO
Published: January 2012

We summarize recent progress in the formulation of a theory for white dwarfs and neutron stars based on the general relativistic Thomas-Fermi equations of equilibrium.
PULSARS: GIGANTIC NUCLEI
Authors: XU RENXIN
Published: January 2012

What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the gigantic nucleus speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction.
PRIMORDIAL STRANGE QUARK MATTER
Authors: LAI XIAOYU , XU RENXIN
Published: January 2012

Strange quark nuggets (SQNs) could be the relics of the cosmological QCD phase transition, and they could very likely be the candidate of cold dark matter if survived the cooling of the later Universe, although the formation and evolution of these SQNs depend on the physical state of the hot QGP (quark-gluon plasma) phase and the state of cold quark matter. We reconsider the possibility of SQNs as cold dark matter, and discuss the astrophysical consequences of primordial SQNs in the early and present universe. In the early Universe, the formation of black holes inside primordial halos could be faster than that in the standard scenario, and speed up the formation of the supermassive black holes at high redshift. In the present Universe, the capture of SQNs by pulsars could trigger star-quakes, which could be the mechanism for pulsar-glitches.
TOP QUARK DECAYS IN EXTENDED MODELS
Authors: LOZANO RICARDO GAITÁN , CABRAL-ROSETTI LUIS G.
Published: January 2012

We evaluate the FCNC decays t → H0 + c at tree-level and t → γ + c at one-loop level in the context of Alternative Left-Right symmetric Models (ALRM) with extra isosinglet heavy fermions; in thr first case, FCNC decays occurs at tree-level and they are only suppressed by the mixing between ordinary top and charm quarks.