Amalgamation of aligned carbon nanostructures at low temperature and the synthesis of vertically aligned carbon nanofibers (CNFs)

This research article discusses the amalgamation of different carbon nanostructures at low temperature and reports a highly reliable and efficient method for the growth of vertically aligned carbon nanofibers (CNFs). The inductively coupled plasma enhanced chemical vapor deposition method utilizes a low substrate temperature (approx. 650 °C) for the growth purpose using toluene as carbon source. First, this paper describes the experimental setup for the synthesis of different nanostructures, then the calibration procedures for the measurement accuracy of the system and then the synthesis of vertically aligned carbon nanofibers using inductively coupled plasma enhanced chemical vapor deposition. Carbon nanofibers are characterized using SEM (scanning electron microscopy), EDX (energy-dispersive X-ray) and Raman spectroscopy.

     

Enhanced conductivity of aligned PANi/PEO/MWNT nanofibers by electrospinning

Conducting composite nanofibers were fabricated from a mixture of multiwalled carbon nanotubes (MWNTs) and a polyaniline (PANi)/poly(ethylene oxide) (PEO) blend using an electrospinning process. We observed a surprising transition in the electrical conductivity of the conducting composite nanofibers while measuring the I–V characteristics of the nanofibers aligned on an electrode when they were exposed to an applied high voltage. We believe that this unexpected transition is closely related to the self-heating of the MWNTs incorporated into the conducting polymer. This type of self-heating method will be very helpful in enhancing the electrical properties of nanoscale conducting composite fibers.     

Analysis on the evolution of the discourse on computer software and programming languages in the light of literary genres and POWER-KNOWLEDGE

Although much analyses have been performed on the collaborative nature of software development in papers (7, 8, 9 and 10) with some of them in the perspective of Vygotsky’s Activity theory, less focus has been given on the discursive evolution of software as different ‘Genres’. In this article we will investigate discursive formation of software and the programming languages in course of time driven by increased ‘Activities’, ‘Dialogue’ and ‘Power’ exercised by certain user groups and entities which will complement our efforts with Activity theory and Foucaultdian POWER-KNOWLEDGE. We will show that POWER relation is affecting user preferences, choices and activities, which are producing changes in the programming languages and creating new software genres. We have borrowed the term ‘Genre’ from the literary studies of Bakhtin and applying it for software. The way different coexisting social classes in a specific time in history leave their fingerprints in different speech and text-genres, we claim that similar mechanisms exist in the software world. We will show that a modern software system is developing improved ‘Dialogism’ or ‘Intertextuality’, ‘Chronotope’ ‘Heteroglossia’ and forming its own discourse. Our presentation is heavily dependent on Mikhail Bakhtin’s concept of literary genres and Foucaultdian concept of POWER-KNOWLEDGE.     

Carbon‐nanotube electron emitters for display applications

Abstract— The optoelectronic, mechanical, and thermal properties of carbon nanotubes have made them very attractive for a wide range of potential applications. However, many applications require the growth of aligned/micropatterned carbon nanotubes with or without a modified nanotube surface. We have developed several simple pyrolytic methods for large‐scale production of aligned carbon‐nanotube arrays perpendicular to the substrate surface. We have also used photolithographic and soft‐lithographic techniques to pattern our aligned carbon nanotubes with submicron resolution. These aligned carbon‐nanotube arrays can be transferred onto various substrates of particular interest (e.g., on conducting substrates as electron emitters for flat‐panel displays) in either a patterned or non‐patterned fashion. The well‐aligned structure further allows us to prepare aligned coaxial nanowires of carbon nanotubes sheathed with polymers and to modify the surface of individual carbon nanotubes by plasma treatment. These aligned/micropatterned carbon nanotubes with and without surface modification possess desirable properties for electron emission applications.     

Barriers in the selection of offshore software development outsourcing vendors: An exploratory study using a systematic literature review

Context

Software development outsourcing is a contract-based relationship between client and vendor organisations in which a client contracts out all or part of its software development activities to a vendor, who provides agreed services for remuneration.

Objective

The objective is to identify various barriers that have a negative impact on software outsourcing clients in the selection process of offshore software development outsourcing vendors.

Method

We have performed a systematic literature review (SLR) process for the identification of barriers. We have performed all the SLR steps such as the protocol development, initial selection, final selection, quality assessment, data extraction and data synthesis.

Results

We have identified barriers such as ‘language and cultural barriers’, ‘country instability’, ‘lack of project management’, ‘lack of protection for intellectual property rights’ and ‘lack of technical capability’ that generally have a negative impact on outsourcing clients. We have identified only one common frequently cited barrier in three types of organisations (i.e. small, medium and large) which is ‘language and cultural barriers’. We did not identify any common frequently cited barrier in three continents (Asia, North America and Europe) and in two decades (1990-1999 and 2000-mid 2008). The results also reveal the similarities and differences in the barriers identified through different study strategies.

Conclusions

Vendors should address frequently cited barriers such as ‘language and cultural barriers’, ‘country instability’, ‘lack of project management’, ‘lack of protection for intellectual property rights’ and ‘lack of technical capability’ in order to compete in the offshore outsourcing business.     

Embedding visual cognition in 3D reconstruction from multi-view engineering drawings

In this paper we discuss how to reconstruct 3D models from multi-view engineering draws by employing human engineers’ approaches. Human's ‘divide and conquer’ interpretation strategy in visual cognition is simulated, and successfully carried out on the basis of spatial division of 3D object space. At first, a volume-oriented method is utilized to decompose the 3D object space in a set of 3D ‘cell-boxes’ whose three-view bounding rectangles will isolate its related sub-projections from input projections views, and in every cell-box a cell primitive is implied. Then, a 3D model of each cell primitive is ‘locally’ generated from its ‘sub-projection’ views by wire-frame oriented algorithms. The final interpretation result of the overall projection-views is a ‘Union’ of these cell primitives. To deal with the ambiguity, a visual reasoning engine is implemented on the basis of principles from Gestalt psychology. It will be activated to pick out the most reasonable interpretation, when ambiguities are generated during the reconstruction process. The section views are also incorporated in getting rid of the ambiguity. Moreover, we design a natural and convenient interaction way to encourage the user to be involved in the process while interpreting complex projections. The key steps of this human-like reconstruction approach are presented in detail.     

Advanced liquid‐crystal materials for TFT monitor and TV applications

Notebook applications have been one of the most important driving forces behind the remarkable growth of liquid‐crystal displays (LCDs). LCDs have recently been well accepted in the monitor market and large growth is forecasted because of the replacement of CRTs. The next challenge for LCDs is the TV market. These new application areas are supported by advanced LC technologies such as film‐compensated twisted nematic (TN), in‐plane switching (IPS), and vertically aligned (VA) modes. Each TFT technology requires a corresponding LC material improvement. We will review the recent liquid‐crystal material development for these advanced LC technologies.     

Expectations and reality: Evaluating patterns of learning behaviour using audit trails

Developers of educational multimedia programs have expectations about the way in which they will be used. These expectations can be broadly categorised as either functional (primarily related to the interface) or educational (related to learning designs, processes and outcomes). However, student users will not always engage with educational multimedia in the ways developers envisage and the adoption of a particular learning design, however well implemented, does not guarantee particular learning processes or outcomes. We investigated the relationship between intended and actual user behaviour by analysing detailed electronic records of user activities (audit trails) within a multimedia program in which medical students adopt the role of a doctor in a simulated clinical interview. Audit trails of 294 users across three years were analysed, focussing on two critical learning activities (interviewing and note taking). Cluster and χ² analyses revealed four distinct types of users: ‘confused or strategic’ (12.9%), ‘disengaged’ (40.8%), ‘expected’ (26.5%) and ‘diligent’ (19.7%). Our work in the future will focus on using audit trails in investigations of students learning processes and outcomes in educational multimedia environments.     

Drawing curves onto a cloud of points for point-based modelling

Point-based geometric models are gaining popularity in both the computer graphics and CAD fields. A related design/modelling problem is the focus of the reported research: drawing curves onto digital surfaces represented by clouds of points. The problem is analyzed and solved, and a set of ‘design tools’ are proposed which allow the user/designer to efficiently perform ‘product development’ (alternative name: ‘detail design’) tasks which require efficient processing of a ‘digital surface’. The primary tool is a robust and efficient point projection algorithm combined with a smoothing technique for producing smooth ‘digital curves’ lying onto the cloud surface. The new design tools are tested on a real-life industrial example with very satisfactory results, which are thoroughly presented in the paper.     

Improving multikey Quicksort for sorting strings with many equal elements

Bentley and Sedgewick proposed multikey Quicksort with ‘split-end’ partitioning for sorting strings. But it can be slow in case of many equal elements because it adopted ‘split-end’ partitioning that moves equal elements to the ends and swaps back to the middle. We present ‘collect-center’ partitioning to improve multikey Quicksort in that case. It moves equal elements to the middle directly like the ‘Dutch National Flag Problem’ partitioning approach and it uses two inner loops like Bentley and McIlroy's. In case of many equal elements such as DNA sequences, HTML files, and English texts, multikey Quicksort with ‘collect-center’ partitioning is faster than multikey Quicksort with ‘split-end’ partitioning.     

Posture evaluations of tethering and loose-housing systems in dairy farms

The purpose of this study was to evaluate the most common simultaneous and individual segment postures in terms of body and finger posture classifications. Observations were made at three dairy farms. One employed a tethering system and the other two used loose-housing systems. The evaluations of the tethering system were performed through six processes that were subdivided into 11 operations, whereas only one process of ‘milking’ was investigated in loose-housing systems. Generally, farmers who worked in both systems bent and/or twisted their upper-body segments and continuously used a power grasp to wrap an object with all five fingers. Posture analyses of the tethering system revealed that ‘moving corn’ seemed less stressful, whereas ‘cleaning udders,’ ‘attaching the machine,’ ‘washing the machine,’ and ‘sweeping the floor’ were more stressful than other operations. Postural workloads on the trunk and head were greater in the tethering system than in the loose-housing systems due to differences in implements, the working height, and the working distance.     

Causal attributions of success and failure made by undergraduate students in an introductory-level computer programming course

The purpose of this research is to identify the causal attributions of business computing students in an introductory computer programming course, in the computer science department at Notre Dame University, Louaize. Forty-five male and female undergraduates who completed the computer programming course that extended for a 13-week semester participated. Narrative interviews were conducted to obtain their perceptions. While some research confirmed that the four most responsible causes for success and failure in achievement contexts are ability, effort, task difficulty, and luck, this research shows that in its context ‘ability’ and ‘luck’ were absent, and ‘task difficulty’ and ‘effort’ were almost absent. In all, participants made 10 causal attributions that were either cultural or specific to computer programming. The 10 causal attributions are ‘learning strategy’, ‘lack of study’, ‘lack of practice’, ‘subject difficulty’, ‘lack of effort’, ‘appropriate teaching method’, ‘exam anxiety’, ‘cheating’, ‘lack of time’, and ‘unfair treatment’. All high achievers cited appropriate ‘learning strategy’.     

Design with part behaviors: behavior model, representation and applications

A part is primarily characterized by its ‘function(s)’. The function of the part is achieved through its ‘interactions’ with other parts in an assembly under a set of operating conditions. These ‘interactions’ constitute the ‘behavior’ of the part. The ‘part behavior’ is achieved through a set of spatial and design functional relationships between the interacting surfaces of the parts. The set of spatial and design functional relationships for a part constitutes the Part Function Model (PFM) of that part. In this paper, the nature and role of part ‘functions’ and ‘behaviors’ have been studied in the context of a product design system. The paper addresses the following issues: (i) relationship between function, behavior, and geometry of a part; (ii) importance of ‘part behavior’ over ‘part function’, and development of a ‘part behavior’ model; (iii) methodology for transforming the part behaviors into the PFM model of the part; (iv) product model framework for storing the PFM model information with an Object Oriented Programming (OOP) based CAD system (Concentra's Concept Modeller); (v) importance of the PFM model within the product development process; and (vi) application of the PFM model for generating various product specifications of the part. The prototype implementation of a Functional Design System for transforming part behaviors into different types of part specifications has also been presented in this paper.     

LPG sensing properties of Pd-sensitized vertically aligned ZnO nanorods

One-dimensional (1-D) vertically aligned ZnO nanorods are synthesized on glass substrate through a simple chemical route and their liquefied petroleum gas (LPG) sensing properties are studied. The morphology and structure of vertically aligned ZnO nanorods has been characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The LPG sensing properties of the vertically aligned ZnO nanorods are improved significantly after palladium (Pd) sensitization. The unsensitized vertically aligned ZnO nanorods exhibited the maximum response of 37% at 573 K upon exposure to 2600 ppm LPG, which improved to 60% at operating temperature of 498 K after the Pd sensitization. The Pd-sensitized vertically aligned ZnO nanorods showed more selectivity towards LPG as compared to CO₂. Our results demonstrate that the chemically grown vertically aligned ZnO nanorods along with Pd sensitization are promising material for the fabrication of cost effective and high performance gas sensors.     

An evaluation of volcanic cloud detection techniques during recent significant eruptions in the western ‘Ring of Fire’

We examined recent volcanic cloud events in the Western Pacific and Indonesian area, to validate the performance of remote sensing techniques used to support the International Airways Volcano Watch (IAVW). Five events were considered, during which eruptions from eight volcanoes injected ash into the upper troposphere or lower stratosphere. For one of the eruptions, at Miyakejima, Japan, at least five aircraft encountered volcanic ash clouds, and the cost to three operators alone exceeded US $12,000,000 in aircraft repairs, diversions, and lost operating time. We performed ‘reverse’ absorption and ‘pattern analysis’ using GMS-5/VISSR, MODIS and AVHRR data, and we examined TOMS SO₂ and Aerosol Index data, surface-based observations, pilot reports, and dispersion model output. Our results verify that the introduction of ‘reverse’ absorption using the geostationary GMS-5 platform significantly enhanced our capacity to monitor volcanic ash clouds in the region. In one case, we tracked an eruption cloud for approximately 80 h. The primary impediment to remote monitoring is the presence of overlying cloud, or substantial amounts of ice within the volcanic clouds. TOMS data showed success in identifying volcanic clouds during these conditions, but was limited by the infrequency of observations. More effective future operation of the IAVW relies on developing complementary methods of volcanic cloud remote sensing, and greatly increasing the amount and quality of available surface and air observations, including observations of precursor activity. An understanding of the likely future limitations of remote sensing techniques will aid in the refining of IAVW procedures.     

CAD tools for aesthetic engineering

The role of computers and of computer-aided design tools for the creation of geometrical shapes that will be judged primarily by aesthetic considerations is reviewed. Examples are the procedural generation of abstract geometrical sculpture or the shape optimization of constrained curves and surfaces with some global ‘cost’ functional. Different possibilities for such ‘beauty functionals’ are discussed. Moreover, rapid prototyping tools based on layered manufacturing now add a new dimension to the visualization of emerging designs. Finally, true interactivity of the CAD tools allows a more effective exploration of larger parts of the design space and can thereby result in an actual amplification of the creative process.     

Computing handle and tunnel loops with knot linking

Many applications seek to identify features like ‘handles’ and ‘tunnels’ in a shape bordered by a surface, embedded in three dimensions. To this end, we define handle and tunnel loops on surfaces which can help identify these features. We show that a closed surface of genus g always has g handle and g tunnel loops induced by the embedding. For a class of shapes that retract to graphs, we characterize these loops by a linking condition with these graphs. These characterizations lead to algorithms for detection and generation of these loops. We provide an implementation with applications to feature detection and topology simplification to show the effectiveness of the method.     

Growth of uniform carbon‐nanotube arrays with sandwich technology

Abstract— In this work, a novel approach to grow structured, highly oriented carbon nanotubes (CNTs), which are vertically aligned to the substrate and show large field emission is reported. Growth is performed on lithographically defined dots of catalysts, which can be deposited on metallic, semiconducting, and glass substrates. A sandwiched catalyst structure and microwave plasma chemical vapor deposition enables the formation of uniform CNT arrays of 1.6 × 1.6 μm². The method is easily scalable to large areas. The CNT arrays exhibit a stable field emission of 20 mA and a macroscopic current density of 50 mA/cm² at a rather low electric field of 5.33 V/μm. Modeling of space charge indicates that space charge reduces the magnitude of the CNT emission at high field strength: this agrees satisfactorily with the measurements.     

Effect of pulse frequency on the morphology and nanoindentation property of electroplated nickel films

This paper reports the effect of pulse current with different frequencies on the morphology and mechanical properties of nickel (Ni) films deposited by electroplating. The pulse frequency varies from 0 (DC) to 500 Hz while the duty cycle (T _on/T _off) is 1 during electroplating. The average roughness and deposition rate of Ni films decrease with the increasing frequency. The smoothest Ni surface with average roughness of 16.5 nm is achieved at the frequency of 500 Hz while the deposition rate reaches a nearly stable rate of 0.04 μm/min. The surface concentration of ions does not vary with time at a sufficiently high frequency with a long off time for ion to diffuse onto the surface. It will result in much more nuclei formed on the surface of cathode at a limited growth rate to get small grains for smooth morphology. The nanohardness of Ni film initially decreases rapidly from 3.9 to 1.18 GPa at 0 to 10 Hz, respectively, then increases to about 4.87 GPa in the range of 100–200 Hz, and decreases slowly to 4.0 GPa at 500 Hz. The stiffness of Ni films electroplated by pulse current at 100–200 Hz is higher than that by dc electroplating. The compromised Ni film with smooth morphology, good hardness and proper deposition rate is obtained at frequency of 100–200 Hz under the current density of 3 Adm⁻².