bluuebunny/crossref_metadata_2025 huggingface dataset:
History and Evolution of the Product Selection Criteria for Selecting Kinetic Hydrate Inhibitors
Authors: Jardine Joanne , Jackson Steven , Longfield Joanne , Cook Stuart Edward , Smith Christina
Published: March 2015

Gas hydrate formation and control is a critical flow challenge that many offshore oil and gas production operations encounter. Formation of hydrates can cause blockage of production flowlines, chokes and valves, which can result in catastrophic failures. Compared to other production problems, hydrate formation is a relatively new phenomenon that is becoming more and more significant with increasing subsea and deepwater developments as well as huge gas projects in the Middle East. The use of low dosage hydrate inhibitors (LDHIs), such as kinetic hydrate inhibitors (KHIs), offer an alternate technical solution to thermodynamic hydrate inhibitors by offering better economics, improved Health, Safety and Environmental (HS&E) performance and less demand on product transportation and storage.

This paper summarizes the history, evolution and current state of KHI laboratory testing requirements. Improvements in laboratory techniques to evaluate the performance of KHI in sweet and sour environments will be discussed. The results of the evaluation are based on laboratory conditions and the ability of a KHI to successfully inhibit hydrate formation in sweet and sour rocking cells. Recent testing has shown significant differences between sweet and sour environments and the ability of the KHI to successfully inhibit hydrate formation under laboratory conditions.

The secondary properties of a selected KHI are becoming more important so are advances in evaluating these properties, in particular the stability and applicability of a KHI under proposed system conditions. Hydrates may form different structures depending on the gas composition of the produced fluids. The nature of the KHI used needs to take into consideration. Recent product developments in this area show that these challenges can be met with appropriate lab testing.

INTRODUCTION

Flow assurance is critical during the efficient production of hydrocarbons from offshore and subsea assets. Gas hydrate formation and control is a critical flow assurance challenge that many offshore oil and gas production operations encounter. The interaction of low-molecular weight gases such as small chain hydrocarbon, and acidic gases like carbon dioxide and hydrogen sulfide, with water under "high" pressure and "low" temperature within a pipeline can form gas hydrates. Gas hydrates are essentially a gas molecule encapsulated by water molecules which have an ice like appearance. Two types of hydrate structure form in gas pipelines, type II being the most common and associated with larger gas molecules such as ethane and propane and type I mainly associated with lean gas and/or carbon dioxide or hydrogen sulfide production. Gas hydrate crystals may agglomerate and/or anneal to form plugs that results in lost production and may incrase (HS&E) risks. Formation of hydrates can cause blockage of production flowlines, chokes and valves, which can result in potentially catastrophic failures.
Verification of the hydrocarbon accumulation in the fault leaned closure with small fault throw: Case study for the Late Miocene Deltaic Sandstone Reservoirs (Sarawak Cycle V) Block D, Sarawak, Malaysia
Authors: Uchimura Ryuichi , Yoshikawa Kosuke , Adian Syafiza , Terabe Kazunobu , Yasukochi Toru , Chin Pei Tze , Yii Chiu Jin
Published: March 2015

Extended Abstract

An exploration well was drilled into a fault-lean 3-way-dip closure along the proven Miri-Rasau anticline. The trapping fault has the largest throw in its central part and dies out laterally and downward. However, we discovered 350m of net hydrocarbon column in six thick sandstones trapped only by the lower part of the fault where its throw was minimal. The throw at the deepest discovery is not clear on seismic but is recognizable only by bends of seismic events. Since the fault throw is smaller than the sandstone thickness, extensive sand to sand juxtaposition is expected unless there is a continuous clay smear. This study aims to evaluate the mechanism of fault trap using available quantitative methods.

New 3D seismic data acquired after the discovery was interpreted in detail around the fault block and careful editing was made for depth converted maps to establish the detailed framework model. A lithology (Vsh) model was also established based on well/seismic data utilizing a geostatistic method.

First, juxtaposition across the fault was identified based on the 3D model. Second, quantitative fault sealing capacity analyses for Shale Gouge Ratio (SGR) and Shale Smearing Factor (SSF) were performed along individual fault planes using fault throw and Vsh at each cell using Structural and Fault Analysis (RDR) module in Petrel (Schlumberger TM). Third, the SGR model was then converted to a maximum potential hydrocarbon-column height (HCH).
Designing a Business Transformation Strategy for Integrated Operations
Authors: Dawam Abdul Ghaffar , Wong Fadhli , Bonilla Juan Carlos Gonzalez
Published: March 2015

PETRONAS Carigali Sdn Bhd has embarked on a journey to incorporate Integrated Operations (IO) concepts as a standard way of working across their production business. Early on it was identified that the implementation of IO as a core enabling element within the production business would create a fundamental change in operations - transforming decision-making from a mechanical process to an organic capability by embedding a culture of collaboration as the basis of an asset's Operations Philosophy (i.e. an asset mindset operating within a functional organization). This fundamental change would require visible leadership in addition to the management of incremental implementation steps: a combined top-down, bottom-up approach.

Further, there would be long term structural transformation due to: scale (the change affects multiple assets not only individually but also collectively with significant implications to the rest of the organization), magnitude (it will involve significant alterations to information availability, capability, and decision-making processes), duration (implementation will span a number of years), and strategic importance to PETRONAS' future business.

Consequently, a comprehensive IO business transformation strategy was required, based on an in-depth understanding of what the implications of the various asset-level digital field solutions are for the organization as a whole, as well as individual stakeholders, driving a plan customized to optimally lead the adoption effort through tailored interventions by business unit, location, role, function, and decision-making patterns.

This paper will review the specific implications of IO within the organization and present how a business transformation strategy was developed to optimally manage the consequences, while mitigating the risks to success.

Executive Summary

The following statements form the basis of the IO transformation strategy and implementation plan:Implementation of IO will create a fundamental change in operations by:a.Transforming decision-making from a mechanical process to an organic capabilityb.Enabling new opportunities for extending field life, improving recovery factor, empowering HSE and optimizing productionc.Embedding a culture of collaboration at the core of an asset's Operations Philosophy: an asset mindset operating within a functional organizationd.Addressing organizational challenges between central office and field personnel
Special issue – Hearing, aging and cognitive disorders Resting state network changes in aging and cognitive decline
Authors: Baldassarre Antonello , Corbetta Maurizio
Published: March 2015

Identifying the neural mechanisms related to aging in the lifespan represents a fundamental goal for clinical neuroscience. Here, we review recent advances in understanding the effects of aging on spontaneous brain activity and behavior. A large body of neuroimaging studies shows that spontaneous brain activity is intrinsically organized in large-scale resting-state networks (RSNs) associated with different cognitive functions such as memory, attention, language, and executive control. Furthermore, recent lines of evidence indicate that aging affects the patterns of correlated brain activity (functional connectivity) within and across RSNs. A common observation is that elderly individuals exhibit decreased functional connectivity within specific RSNs such as the default mode, dorsal attention and executive-control networks. Moreover, aging is associated with increased inter-network functional connectivity between RSNs, i.e. reduction of segregation between functional systems. Finally, some studies show that changes in functional connectivity are behaviorally relevant, i.e. they are correlated with a decline in cognitive abilities, mainly in memory and executive control functions. These findings strongly suggest that robust changes in RSNs occur in aging; hence investigations of spontaneous brain activity may shed light into brain processes related to aging or serve as a sensitive biomarker of cognitive decline and response to therapy.
Long-term outcomes in primary spinal osteochondroma: a multicenter study of 27 patients
Authors: Sciubba Daniel M. , Macki Mohamed , Bydon Mohamad , Germscheid Niccole M. , Wolinsky Jean-Paul , Boriani Stefano , Bettegowda Chetan , Chou Dean , Luzzati Alessandro , Reynolds Jeremy J. , Szövérfi Zsolt , Zadnik Patti , Rhines Laurence D. , Gokaslan Ziya L. , Fisher Charles G. , Varga Peter Paul
Published: March 2015

OBJECT

Clinical outcomes in patients with primary spinal osteochondromas are limited to small series and sporadic case reports. The authors present data on the first long-term investigation of spinal osteochondroma cases.

METHODS

An international, multicenter ambispective study on primary spinal osteochondroma was performed. Patients were included if they were diagnosed with an osteochondroma of the spine and received surgical treatment between October 1996 and June 2012 with at least 1 follow-up. Perioperative prognostic variables, including patient age, tumor size, spinal level, and resection, were analyzed in reference to long-term local recurrence and survival. Tumor resections were compared using Enneking appropriate (EA) or Enneking inappropriate surgical margins.

RESULTS

Osteochondromas were diagnosed in 27 patients at an average age of 37 years. Twenty-two lesions were found in the mobile spine (cervical, thoracic, or lumbar) and 5 in the fixed spine (sacrum). Twenty-three cases (88%) were benign tumors (Enneking tumor Stages 1–3), whereas 3 (12%) exhibited malignant changes (Enneking tumor Stages IA–IIB). Sixteen patients (62%) underwent en bloc treatment—that is, wide or marginal resection—and 10 (38%) underwent intralesional resection. Twenty-four operations (92%) followed EA margins. No one received adjuvant therapy. Two patients (8%) experienced recurrences: one in the fixed spine and one in the mobile spine. Both recurrences occurred in latent Stage 1 tumors following en bloc resection. No osteochondroma-related deaths were observed.

CONCLUSIONS

In the present study, most patients underwent en bloc resection and were treated as EA cases. Both recurrences occurred in the Stage 1 tumor cohort. Therefore, although benign in character, osteochondromas still require careful management and thorough follow-up.
Fabrication and Characterization of Polysaccharide Ion Gels with Ionic Liquids and Their Further Conversion into Value-Added Sustainable Materials
Authors: Takada Akihiko , Kadokawa Jun-ichi
Published: March 2015

A review of the fabrication of polysaccharide ion gels with ionic liquids is presented. From various polysaccharides, the corresponding ion gels were fabricated through the dissolution with ionic liquids. As ionic liquids, in the most cases, 1-butyl-3-methylimidazolium chloride has been used, whereas 1-allyl-3methylimidazolium acetate was specifically used for chitin. The resulting ion gels have been characterized by suitable analytical measurements. Characterization of a pregel state by viscoelastic measurement provided the molecular weight information. Furthermore, the polysaccharide ion gels have been converted into value-added sustainable materials by appropriate procedures, such as exchange with other disperse media and regeneration.
Design of an LLC Resonant Converter for Driving Multiple LED Lights Using Current Balancing of Capacitor and Transformer
Authors: Han Jae-Hyun , Lim Young-Cheol
Published: March 2015

In this study, to achieve the constant current drive and brightness control without a separate pulse width modulation (PWM) converter, a single converter is designed and verified by experiment under the condition of a multiple LED light load with different output voltage (Vf) characteristics. In the case of the input of 140 Watt class level, the proposed converter can drive two voltage type 95 Vdc (300 mA) light emitting diode (LED) lights loads and 120 Vdc (300 mA) LED lights loads simultaneously. In addition, to improve commercial compatibility, the proposed converter is operated in a wide range of the input voltage 90~264 Vac; also, the Power Factor Correction (PFC) circuit with the input power factor of more than 0.9 is added. In order to maximize the power conversion efficiency, a LLC resonant converter is applied to the PFC block with the output voltage of 380 Vdc and to a DC-DC conversion block. Finally, reliability of the proposed converter is verified through total harmonic distortion (THD) and electromagnetic interference (EMI) tests.
Multiple q-Zeta Brackets
Authors: Zudilin Wadim
Published: March 2015

The multiple zeta values (MZVs) possess a rich algebraic structure of algebraic relations, which is conjecturally determined by two different (shuffle and stuffle) products of a certain algebra of noncommutative words. In a recent work, Bachmann constructed a q-analogue of the MZVs—the so-called bi-brackets—for which the two products are dual to each other, in a very natural way. We overview Bachmann’s construction and discuss the radial asymptotics of the bi-brackets, its links to the MZVs, and related linear (in)dependence questions of the q-analogue.
Is Cyberbullying a Stand Alone Construct? Using Quantitative Analysis to Evaluate a 21st Century Social Question
Authors: Randa Ryan , Nobles Matt , Reyns Bradford
Published: March 2015

Using a subsample of the 2009 National Crime Victimization Survey, School Crime Supplement (NCVS-SCS), the present study explores the nature of the relationship between cyberbullying and traditional bullying victimization among students aged 12–18. One question of particular interest in the recent cyberbullying literature regards the classification of cyberbullying relative to traditional school yard bullying. As is the case in the cyber victimization literature in general, the question has become whether cyberbullying is an extension of traditional bullying or whether it is a unique independent phenomenon. Using the available data we attempt to address this question by exploring cyberbullying victimization as a standalone construct. Results of exploratory factor analyses suggest that cyberbullying victimization is both interlaced with traditional bullying modalities, and experienced as a unique phenomenon. Our results contribute a 21st century texture and dimension to the traditional construct.
Sustainability Aspects of Energy Conversion in Modern High-Speed Trains with Traction Induction Motors
Authors: Rosen Marc , Nicola Doru , Bulucea Cornelia , Cismaru Daniel
Published: March 2015

Some aspects are illustrated of energy conversion processes during the operation of electric railway vehicles with traction induction motors, in order to support transport systems’ sustainability. Increasing efforts are being expended to enhance the sustainability of transportation technologies and systems. Since electric drive systems are used with variable voltage variable frequency (VVVF) inverters and traction induction motors, these machines with appropriate controls can realize both traction and electric braking regimes for electric traction vehicles. In line with this idea, this paper addresses the operation sustainability of electric railway vehicles highlighting the chain of interactions among the main electric equipment on an electrically driven railway system supplied from an a.c. contact line: The contact line-side converter, the machine-side converter and the traction induction motor. The paper supports the findings that electric traction drive systems using induction motors fed by network-side converters and VVVF inverters enhance the sustainable operation of railway trains.
Emerging Influenza Strains in the Last Two Decades: A Threat of a New Pandemic?
Authors: Trombetta Claudia , Piccirella Simona , Perini Daniele , Kistner Otfried , Montomoli Emanuele
Published: March 2015

In the last 20 years, novel non-seasonal influenza viruses have emerged, most of which have originated from birds. Despite their apparent inability to cause pandemics, with the exception of H1N1 swine influenza virus, these viruses still constitute a constant threat to public health. While general concern has decreased after the peak of the H5N1 virus, in recent years several novel reassorted influenza viruses (e.g., H7N9, H9N2, H10N8) have jumped the host-species barrier and are under surveillance by the scientific community and public health systems. It is still unclear whether these viruses can actually cause pandemics or just isolated episodes. The purpose of this review is to provide an overview of old and novel potential pandemic strains of recent decades.
Developing a Market-Specific Destination Image Scale: A Nomological Validation Approach
Authors: Chen Chun-Chu , Lin Yueh-Hsiu , Gao Jie , Kyle Gerard
Published: March 2015

This study intended to develop a scale to measure the image of a destination as perceived by tourists from a specific market. Based on Echtner and Ritchie's framework of destination image, cognitive image was conceptualized as the composite of common image and two salient dimensions—unique
and atmospheric images. The scales measuring these three constructs were validated within the theoretical framework of attitude theory. The results showed that all three constructs had significant effects on affective image and travel intention, while travel intention could be better predicted
by two salient dimensions. These findings highlighted the importance of capturing salient dimensions and attributes in the process of scale development.
Volunteer Experiences on Organic Farms: A Phenomenological Exploration
Authors: Miller Maggie C. , Mair Heather
Published: March 2015

This article presents an exploration of the understudied phenomenon of volunteering on organic farms, a movement associated with World Wide Opportunities on Organic Farms (WWOOF). Using a hermeneutic phenomenological lens influenced by philosophies of Hans George Gadamer, this article
illuminates experiences of volunteers on organic farms in Argentina, experiences we denote as “organic volunteering.” Our use of phenomenology provides an opportunity to develop deeper understandings of these lived experiences and what they mean to volunteers. Data collection and
analysis of active interviews and participant observation with volunteers revealed a central understanding of opening to living in interconnectedness, which is underpinned by six horizons of understanding: 1) reconnecting, 2) exchanging knowledge, 3) experiencing harmony, 4) bonding with others,
5) consciousness raising, and 6) transforming. Our work suggests that while these experiences are likely similar to volunteer or even alternative tourism broadly defined, organic volunteering encompasses aspects that may extend beyond what has been put forward by volunteer tourism researchers,
and is perhaps its own niche of alternative tourism.
Strategic Marketing Development of Hospitals Participating in Medical Tourism: A Case of South Korea
Authors: Choi Keetag , Lee Timothy J. , Kim Hwa-Kyung
Published: March 2015

This article highlights the strong potential and growing popularity of the Asian medical tourism industry focusing on South Korea and presents an overview of the background of the industry, the current situation, issues of concern, and directions to pursue for the systematic development
of the medical tourism industry in that country. It examines the difficulties encountered given that the current medical tourism market in Korea is under constant attention but still at the beginning stages. The study a) examines the recognition and attitudes of hospitals towards medical tourism,
b) investigates networking involvement of the medical tourism-related institutions, and c) suggests recommendations for strategic implementation of medical tourism in Korea. The study provides useful strategic analysis for the sustainable development of the medical tourism industry in a country
where medical tourism is receiving rapidly growing attention.
Study on Phenolic Foams Modified by Graphene Oxide
Authors: Luan Jin Peng , Wei Xin Fang , Zhou Xue Ping , Lu Guo Zhong , Liu Chen Zhao , Li Guo Dong , Na Ya Xin , Wang Hai Wang , Qi Xi Wei
Published: March 2015

After the primary exploration of the preparation procedure of phenolic foam, we studied the modification of phenolic foam by graphene oxide. According to our researches we found that the influence of modifier to the percentage of close area was very little, but it can greatly decrease the thermal conductivity of phenolic foam. In this way, phenolic foam thermal conductivity can be reduced to 0.025 W/m.K.
Study on Constitutive Equation of 7085 Aluminum Alloy under High Deformation Temperature
Authors: Mei Rui Bin , Zhang Bo , Cai B. , Zhang X.Y. , Zou Z.T. , Liu Y.N. , Li C.S.
Published: March 2015

The flow stress behavior of the 7085 aluminum alloy was studied through single-pass compression experiment by using MMS-300 simulator within temperature range of 300-450°C and strain rate range of 0.01-10s-1. Dynamic recrystallization occurs in hot compression of 7085 alloy and the stress-strain curves are presented as wave with higher deformation temperature and strain rate. Increasing of deformation velocity and reducing temperature results in higher peak stress. Then a mathematical model has been developed to predict the stress-strain curves based on phenomenological representation of the curves and the traditional theories for constitutive equations which incorporate the power law. The constitutive equation expressed in terms of peak stress, peak strain and additional parameters to predict flow stress. The stress-strain curves of 7085 alloy predicted by this model are in good agreement with experimental results.
Goal Driven Optimization of Process Parameters for Maximum Efficiency in Laser Bending of Advanced High Strength Steels
Authors: Griffiths Jonathan , Riley Mike J.W. , Sheikholeslami Ghazal , Edwardson Stuart P. , Dearden Geoff
Published: March 2015

Laser forming or bending is fast becoming an attractive option for the forming of advanced high strength steels (AHSS), due primarily to the reduced formability of AHSS when compared with conventional steels in traditional contact-based forming processes. An inherently iterative process, laser forming must be optimized for efficiency in order to compete with contact based forming processes; as such, a robust and accurate method of optimal process parameter prediction is required. In this paper, goal driven optimization is conducted, utilizing numerical simulations as the basis for the prediction of optimal process parameters for the laser bending of DP 1000 steel. A key consideration of the optimization process is the requirement for minimal micro-structural transformation in automotive grade high strength steels such as DP 1000.
Investigation of the Portevin-Le Chatelier Effect in AlMgSi-Tailored Heat Treated Blanks
Authors: Kahrimanidis Alexander , Wortberg Daniel , Merklein Marion
Published: March 2015

The dissolution of co-clusters in AlMgSi-alloys by a short term heat treatment can be used to locally adjust the mechanical properties of a blank for a following forming operation. This approach is known as Tailored Heat Treated Blanks (THTB) and allows to significant enhance the forming limits of AlMgSi-alloys. However, the dissolution of co-clusters leads to the observation of the Portevin-Le Chatelier (PLC) effect during deformation. The results are stretcher strain marks at the surface which are a limitation for potential applications of THTB. In contrast to AlMg-alloys, a critical strain rate above which no PLC effect occurs is not observed for the investigated alloys. This paper investigates various influence factors on the occurrence of the PLC effect for different AlMgSi-alloys and presents an approach under which conditions THTB can be used in applications with high demand on surface quality.
Negative Bulge Formation in High Speed Incremental Forming
Authors: Vanhove Hans , Duflou Joost R.
Published: March 2015

As a flexible process, Single Point Incremental Forming has the potential to be widely used as a technique for prototyping, discrete or small batch production. However, its notorious lack of accuracy and formability limit a wide adoption on an industrial scale. While the main factor constraining the feasible batch size is the limited processing speed, recent developments towards High Speed SPIF have moved this restricting boundary considerably. Increased strain rates and friction in HS-SPIF introduce their own specific influence on the achievable accuracy. This paper aims to investigate the effect of HS-SPIF on the bulging of the bottom of a work piece. This explicit type of inaccuracy, also known as the pillowing effect, is mainly located in a region of the sheet which is to be left unprocessed, and is therefore challenging to eradicate. Different papers have focused on bulging of a sheet in conventional SPIF, resulting in knowledge about the inwards bending of the sheet at low wall angles. HS-SPIF, however, tends to show a previously unseen outwards bulge at high wall angles due to its unique thermal behavior.
Stamping Plant 4.0 – Basics for the Application of Data Mining Methods in Manufacturing Car Body Parts
Authors: Purr Stephan , Meinhardt Josef , Lipp Arnulf , Werner Axel , Ostermair Martin , Glück Bernhard
Published: March 2015

Data-driven quality evaluation in the stamping process of car body parts is quite promising because dependencies in the process have not yet been sufficiently researched. However, the application of data mining methods for the process in stamping plants would require a large number of sample data sets. Today, acquiring these data represents a major challenge, because the necessary data are inadequately measured, recorded or stored. Thus, the preconditions for the sample data acquisition must first be created before being able to investigate any correlations. In addition, the process conditions change over time due to wear mechanisms. Therefore, the results do not remain valid and a constant data acquisition is required. In this publication, the current situation in stamping plants regarding the process robustness will be first discussed and the need for data-driven methods will be shown. Subsequently, the state of technology regarding the possibility of collecting the sample data sets for quality analysis in producing car body parts will be researched. At the end of this work, an overview will be provided concerning how this data collection was implemented at BMW as well as what kind of potential can be expected.
Locally Adapted Tribological Conditions as a Method for Influencing the Material Flow in Sheet-Bulk Metal Forming Processes
Authors: Loeffler Maria , Schneider Thomas , Vierzigmann Ulrich , Engel Ulf , Merklein Marion
Published: March 2015

Due to ecological and economic challenges there is a growing demand for lightweight construction by using closely-tolerated complex functional components with variants. Conventional sheet and bulk metal forming operations are often improvident in producing such parts. A promising approach is the process-class “sheet-bulk metal forming” (SBMF). Within SBMF bulk forming operations are applied to sheet metals, often in combination with sheet forming operations [1]. This leads to a significant gradient in load conditions regarding stress and strain states and causes locally varying tribological conditions. Thus, the investigation of the tribological conditions and the provision of suited tribological systems are essential for the successful application of SBMF processes. The objective of the current study is the experimental investigation of the applicability of tribological adaptions by local abrasive blasting on a single-stage process combination of deep drawing and upsetting to produce a component with an external gearing. The manipulation of the local tribological conditions by the use of abrasive blasting leads to a better control of the material flow and in consequence to an improved quality of the components in terms of higher mould filling and cup heights, and a reduced thickening of the sheet in the area of the cup bottom.
Notch Shear Cutting of Press Hardened Steels
Authors: Feistle Martin , Krinninger Michael , Golle Roland , Volk Wolfram
Published: March 2015

Nowadays, lightweight design is a relevant issue in the automotive industry and in the field of electric mobility. The utilization of Press Hardened Components (PHC) made of manganese-boric steels enable weight saving through the reduction of the sheet metal thickness with sufficient component reliability. Because of the hard martensitic structure, by default, laser cutting is applied for piercing and trimming the contour after the Press Hardening Process (PHP). Due to the high energy consumption, in combination with long cycle times, this process is cost intensive.Instead of laser technology, shear cutting would be an interesting alternative for Press Hardened Steels (PHS) but this process poses substantial challenges for the industrial application. In order to cope with the difficulties of shear cutting operations of PHS, this work presents an alternative for processing PHS. This new method is called notch shear cutting.
Preparation of Bead-on-String Nanofibers and its Application for the Removal of Bisphenol A
Authors: Qiu Fang , Peng Min Le , Wei Zhi Mei , Zhang Gang , Long Sheng Ru , Wang Xiao Jun , Yang Jie
Published: March 2015

Bead-on-string nanofibers were prepared by electrospinning, in this work, . The effect of processing parameters and property of solutions on the morphology of bead-on-string nanofibers were systematically investigated. The results revealed that the morphology of beads on nanofibers transformed from spherical into spindle-like with increased concentration of solution, applied voltage and needle-collector distance. Average width of beads became smaller as increasing all the values of processing parameters. Meanwhile, the application for the removal of bisphenol A (BPA) from aqueous solution was investigated, and results showed that the bead-on-string nanofibers could effectively remove BPA from aqueous solution. The kinetic data were analyzed by the pseudo-first-order, pseudo-second-order kinetic models. The reusability of the composite nanofiber was also determined after five adsorption–desorption cycles.
Preparation and Characterization of Polylactic Acid Coating on the Surface of Magnesium Alloy
Authors: Hua Xian Yang , He Mei Feng , Zhou Xiao Qin
Published: March 2015

Magnesium is one of the elements necessary for the body, is the man behind the body’s content of potassium ions within the cell are involved in a series of metabolic processes in vivo, including the formation of bone cells , acceleration of bone healing ability. Resulting from the good mechanical properties and biocompatibility, magnesium alloy is used in medical intervention material, but the high corrosion rate of magnesium alloys is the main drawback to their widespread use, especially in biomedical applications. There is a need for developing new coatings that provide simultaneously corrosion resistance and enhanced biocompatibility. In this work the medical magnesium alloy surface are dipped and coated with polylactic acid, so that obtain a dense uniform polylactic acid coating. And the corrosion resistance of the coating is studied in order to obtain controlled degradable and corrosion resisted magnesium alloy biological material. This paper mainly studies the influence of different concentrations of polylactic acid coating on AZ91D magnesium alloy corrosion resistance. The coated samples were immersed in Hank’s solution and the coating performance was studied by electrochemical impedance spectroscopy and scanning electron microscopy. This research is about the influence of the coating on the corrosion resistance of magnesium alloy through the open circuit potential, polarization curves, electrochemical impedance spectroscopy and Mott-Schottky. The results confirmed that the polylactic acid slow down the corrosion rate of AZ91D magnesium alloys in Hank’s solution. And along with the increase of poly lactic acid concentration, the corrosion resistance of magnesium alloys is improved. There is a wide variation of the corrosion morphology magnesium alloy AZ91D specimens after the surface modification using polylactic acid coating, compared with the unmodified.
Synthesis and Properties of the Poly(styrene-acrylic acid)
Authors: Wu Yuan Peng , Zhu Chun Yang , Lin Yuan Hua , Yan Zhu , Yang Hao , Zhou Chang Liang , Singh Ambrish
Published: March 2015

Due to the smalle hole of the shale formantion, particles with smaller size, such as nanoparticles was developed to be used as plugging materials during the drilling of shale formation. In this article, poly (styrene-acrylic acid) particles were synthesized by soap-free emulsion polymerization of styrene (St) and acrylic acid (AA). The as-prepared polymer particles were characterized by Fourier transform infrared spectroscope (FT-IR), dynamic light scattering (DLS). In addition, salt tolerance, temperature resistance and compatible properties with additives in drilling fluid of the polymer particles were also investigated.
Selection of Green Building Materials for Energy-Saving Exterior Windows
Authors: Zhao Chun Zhi , Jiang Quan , Ma Li Ping , Zhao Ping
Published: March 2015

Urban population has been increased rapidly and caused such urban problems as shortage of housing and traffic jam, and the continuously expanding buildings have resulted in strong impact on global resource consumption and environmental pollution. Green building materials are the basic guarantee to the quality and service life of buildings, the material carrier to realize various functions of buildings and also the foundation and support to develop green buildings. Based on the coherence and relevance of assessment on full life cycle of buildings and building materials, the influence of exterior window selection on carbon emission of buildings was analyzed in aspects of the initial stage (production, consumption and transport of building materials) of carbon emission of buildings, i.e. the intrinsic energy per unit product, operation, demolition and treatment. The comprehensive assessment was also established, and the selection of green building materials was investigated for exterior windows based on the reduction of energy consumption during full life cycle of buildings by combining such indicators as the usability, durability, fireproofness, environmental protection and functionality of exterior windows. It solved the puzzles of architects on selection of building materials and the puzzles of building material manufacturers on demand of green buildings. The selection of green building materials on green buildings was promoted and the realization of the goal of "green buildings" also assisted.
Defect-Controlled Gas Sensing Property of Nanostructured ZnO Films
Authors: Chang Yong Qin , Shao Chang Jing , Jiang Nan , Ma Yan Jun , Wang Shi Qi , Zou Bo , Long Yi
Published: March 2015

Nanostructured ZnO films were fabricated by chemical vapor deposition (CVD) method with different Sn source concentrations for ethanol sensing application. It was found that the morphology of the ZnO films were obviously affected by Sn concentration, while no any Sn signals were detected in the films. The response of the nanostructured ZnO films increases with the increase of ethanol concentrations, and the S2 sample displays the highest sensitivity. Thephotoluminescence spectra show that more oxygen vacancies exist in the S2 sample than the other samples, which reveals that oxygen vacancies may play a great role to improve the gas sensing properties of the ZnO films.A possible sensing mechanism was proposed to explain these phenomena.This work provides a very simple and efficient method to prepare ZnO gas sensor, its high response and short recovery time are also a merit for the ZnO films used in gas sensor applications.
Welding Performance of Tungsten Electrodes with Different Contents of Rare Earth Oxides
Authors: Li Yan , Yang Jian Can , Liu Zhen
Published: March 2015

In this paper, the influence of different contents of rare earth oxides of tungsten electrodes on the welding performance has been studied. Tungsten inert gas weld was carried out on 1060 aluminum plate, using different contents of rare earth oxides of tungsten electrodes. The content of CeO2 are 2% and 4%, the content of composite rare earth oxides (La2O3: CeO2: Y2O3 = 1:1:3) is 4%. The mechanical properties of these welded joints were investigated. The results indicated that the loss of the CeO2 content of 4% electrode weight was the maximum. The arc stability of the three kinds of tungsten electrodes was good. The arc static characteristic curve of the composite rare earth—tungsten electrode was lower than that of the cerium—tungsten electrode. The loss of rare earth oxides of electrode had little effect on the mechanical properties of welded joints.
Preparation of Polyvinylidene Fluoride (PVDF) Triboelectric Nanogenerators with Different Polymer
Authors: Wang Cheng , Yu Hao , Huang Tao , Tan Chao
Published: March 2015

Triboelectric nanogenerators have recently been used to harvest mechanical energy from surrounding environment which is of great significance in the field of energy conversion. Electrospinning provides a simple, low cost and versatile method for the generation of 1D nanostrucutures. Nanofiber membranes have many advantages over the commonly used dense film for designing the riboelectric nanogenerators, such as the low wear resistance caused from the internal and excellent external consistency of the electrospinning membranes. In this paper, we produce a variety of polymer films by electro-spinning, and fabricate Polyvinylidene Fluoride (PVDF) triboelectric nanogenerators with different polymer films afterwards. We except to explore the TEG power generation effect, and influencing factors, and then determine the best combination of the results of TEG (PVDF-PHBV). Such a flexible polymer TEG generates output voltage of up to 112 V at a power of 0.045W.
Nickel Nanoparticles Mediated Growth of the Intermetallic Compound between Sn-1.0Ag-Xni Solders Alloy and Cu Substrate
Authors: Zhang Xue Chao , Cheng Jing Wei , Zheng Bing , Zhao Xiu Chen , Liu Ying , Chen Ping
Published: March 2015

In the present study, the effect of addition of Ni nanoparticles on the growth of the intermetallic compound (IMC) layer between low-silver lead-free solder and Cu substrate was investigated. Ni nanoparticles were synthesized and smelted with pure Sn, Ag to prepare Sn-1.0Ag-xNi (x=0, 0.05, 0.1, 0.2) solder alloy. Sn-1.0Ag-xNi was soldered on a copper substrate, and then the solder/Cu couples were isothermally aged at 423K for 360h.The Cross-section images of IMCs layer were obtained to observe the morphology of IMC and to measure the thickness of Cu6Sn5and Cu3Sn layers respectively. The results show that, during aging, addition of Ni can remarkably improve the morphology of IMC, level the scalloped IMC, facilitate the growth of the total interfacial IMCs and inhibit the growth of Cu3Sn. Moreover, the rate change of thickness of the Cu3Sn reduced obviously with the increase of Ni nanoparticles. Comprehensive analysis shows that the addition of Ni promotes the nucleation and growth of Cu6Sn5. The thermodynamics calculation on the solder alloy was identical with the experiment result.
Fabrication and Property of W/Tininb Shape Memory Alloy Laminated Composite
Authors: Shao Yang , Jiang Da Qiang , Guo Fang Min , Ru Ya Dong , Hu Xiao Wei , Cui Li Shan
Published: March 2015

W/TiNiNb shape memory alloy laminated composites were fabricated by vacuum hot press, forging and rolling. The microstructure, transformation behavior, mechanical behavior and damping capacity of the laminated composite were investigated by SEM, DSC, DMA and bending test, respectively. The results showed that the W layer and the TiNiNb shape memory alloy layer in the composite was about 15 μm and 5 μm, respectively. The TiNiNb alloy in the composite exhibited the reversible martensite transformation. The composite also had high damping capacity (tanδ=0.03). The three-point bending test showed various plateaus in the stress–strain curve due to delamination processes, which are suitable for enhancing the fracture toughness of the laminates. The flexure strength of the laminated composite was 1260 MPa.
Features of Different Types of V-Ti Iron Concentrate Powder and their Influences on the Properties of Cold-Bonded Iron Ore Pellets
Authors: Ma Lan , Yang Shao Li , Zhao Jin Tao
Published: March 2015

Three types of V-Ti (vanadium-titanium) iron concentrate powder were studied on their features as well as their influences on the properties of cold-bonded iron ore pellets. The research results indicated that the relations between the fineness modulus of the three types of V-Ti iron concentrate is in the order of LM>HL>SX, and SX has the smallest fineness modulus and particle sizes. The relations between average wetting speed of the three types of iron concentrate powder is in the order of HL>LM>SX, and the wettability of HL powder is the highest. The relations between mixing time of the three types of iron concentrate powder is in the order of SX≈LM>HL. Under the same briquetting pressure, SX had the best pelletizing performance.
Property of an AlGaN/GaN MIS Diode with Si3N4/Al2O3 Bilayer Gate Dielectric Films
Authors: Shen Ling Yan , Cheng Xin Hong , Wang Zhong Jian , Cao Duo , Zheng Li , Xia Chao , Yu Yue Hui
Published: March 2015

Metal-insulator-semiconductor (MIS) diodes with Si3N4/Al2O3 bilayer gate dielectric films deposited on an AlGaN/GaN heterostructure were fabricated, where the Si3N4 layer played a role of etching stopped layer to protect the Al2O3 film from being damaged. Compared with traditional Schottky diodes, a distinct suppression of gate leakage current was achieved for the MIS diodes both at forward and reverse bias, and the dominant leakage current mechanism is Fowler–Nordheim tunneling. The 2DEG density extracted from C-V curves was 3~7 ́1013cm-2, in the same order of magnitude as Schottky diodes and hall measurement. Although the existence of the bilayer dielectric did not affect the 2DEG density at the interface of AlGaN/GaN, Si3N4 layer shared more gate bias and led to more gate bias required to deplete 2DEG and turn down the devices, moreover, Si3N4 layer had no effect on suppressing the forward or reverse gate leakage current due to its narrow band gap width and band bending compared with a single Al2O3 film. The experimental results provided a reference for the design of gate dielectric film structure for AlGaN/GaN high-electron-mobility transistors (HEMTs).
Promoted Chain Diffusion of UHMWPE/HDPE Blend by High Temperature Treatment
Authors: Fan Chun Hua , Kong Hai Zhou , Xie An Zhun , Xie Bang Hu
Published: March 2015

Ultra high temperature treatment was used to promote the molecular chain diffusion of UHMWPE/HDPE blend. At the same time, melt blended sample and solution blended sample were also prepared for a comparison. The phase morphology of the samples observed by scanning electron microscope (SEM) showed that the difference between HDPE and UHMWPE became smaller after high temperature treatment. While the UHMWPE particle could not be observed in solution blending samples. The results of rheological test showed that the elastic modulus and complex viscosity of treated samples are higher than that of untreated samples but still below the viscosity of solution blending sample. The results deem, high temperature treatment indeed promoted the chain diffusion of UHMWPE/HDPE blend and a good fusion between HDPE and UHMWPE is obtained as a result
First-Principles Study on Electronic and Optical Properties of Kesterite and Stannite Cu2ZnSnS4 Photovoltaic Absorbers
Authors: Kong Le , Deng Jin Xiang
Published: March 2015

To find the optical properties of Cu2ZnSnS4(CZTS) absorber in two crystal structures (kesterite and stannite) which are key factors determining solar cell performance and are based on the electronic structures, a systematical calculation of electronic and optical properties were calculated using density functional theory. The results suggested that the optical properties of CZTS had a rather weak dependence on the (Cu, Zn) cation ordering. Kesterite and stannite CZTS both suited for photovoltaics with large light absorption coefficient ( > 104cm-1) in the visible light region that is the most important part for photovoltaics, and kesterite CZTS had larger light absorption than stannite CZTS exhibiting a more obvious advantage. In the visible light region the reflectivity of CZTS was lower than that of silicon, the absorber material used most widely, which might be in favor of light absorption and cell efficiency. Ground-state structure, electronic transitions relevant to solar light absorption, static dielectric constant and plasma frequency were also investigated.
Acute Stimulant Ingestion and Neurocognitive Performance in Healthy Participants
Authors: Powers Michael E.
Published: March 2015

Context

Concussion management has become an area of great concern in athletics, and neurocognitive tests, such as Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), are commonly used as management tools. Given the restrictive nature of current management plans, anecdotal concerns have been raised about athletes trying to cheat the assessments and return to participation sooner. Stimulants have been shown to improve neurocognitive measures similar to those used in ImPACT. Therefore, they could possibly improve performance during baseline and postinjury testing.

Objective

To examine the effects of a supplement containing stimulants on ImPACT performance.

Design

Crossover study.

Setting

Research laboratory.

Patients or Other Participants

A total of 5 men (age = 20.6 ± 1.5 years, height = 176.3 ± 9.6 cm, mass = 76.9 ± 18.6 kg) and 7 women (age = 20.6 ± 1.1 years, height = 162.9 ± 7.8 cm, mass = 60.9 ± 8.2 kg) with no histories of physician-diagnosed head injury, learning disability, or attention-deficit disorder.

Intervention(s)

Participants were assessed under supplement (5.5 g of Jacked 3D, which contains caffeine and 1,3-dimethylamylamine), placebo, and control conditions separated by 1 week.

Main Outcome Measure(s)

I compared ImPACT composite scores for verbal and visual memory, visual motor speed, reaction time, impulse control, and a cognitive-efficiency index under each of the 3 conditions and assessed them 30 minutes after ingestion.

Results

I observed a difference when comparing reaction times, as the participants reacted faster during the supplement condition (0.53 ± 0.03 seconds) than during the placebo (0.55 ± 0.03 seconds) and control (0.55 ± 0.03 seconds) conditions (F2,22 = 4.31, P = .03). A difference also was observed for the cognitive-efficiency index, as participants scored higher during the supplement condition (0.49 ± 0.09) than during the placebo (0.41 ± 0.10) and control (0.41 ± 0.12) conditions (F2,22 = 4.07, P = .03).

Conclusions

Stimulant ingestion 30 minutes before testing resulted in improved memory, visual processing speed, and reaction time. However, the improvements were relatively nominal, and the question of clinical importance remains. Thus, it is unclear if stimulant ingestion would affect the return-to-participation progression.