bluuebunny/crossref_metadata_2025 huggingface dataset:
Petroleum Refinery Secondary Effluent Polishing Using Freezing Processes—Toxicity and Organic Contaminant Removal
Authors: Gao W. , Smith D.W. , Habib M.
Published: June 2008

A petroleum refinery secondary effluent was treated using two freezing techniques—spray freezing and unidirectional downward freezing (UDF). The freezing processes were effective to remove toxicity and total organic carbon (TOC)‐ and chemical oxygen demand (COD)‐causing materials in the effluent. Agitation of the liquid during UDF significantly improved the impurity separation efficiency; 85 to 96% removal of TOC and COD was achieved without any pretreatment and freezing only 70% of the feed water. The treatment efficiency of the spray freezing was at the same level as that of UDF without mixing. The spray ice with longer storage time released more contaminants with early meltwater. The initial contaminant concentration of the feed water and the freezing temperatures (−10°C and −25°C) had no significant influence on the treatment efficiency. A small fluctuation in effluent TOC concentration caused a dramatic change in effluent toxicity (Microtox). The effective concentration (EC 20) (Microtox) was effective in detecting effluent toxicity.
Fly‐Ash‐Amended Sand as Filter Media in Bioretention Cells to Improve Phosphorus Removal
Authors: Zhang Wei , Brown Glenn O. , Storm Daniel E. , Zhang Hailin
Published: June 2008

This study identified material with high phosphorus sorption suitable for bioretention filter media. Materials examined were fly ash, two expanded shales, peat moss, limestone, and two common Oklahoma soils—Teller loam and Dougherty sand. The peat moss was a phosphorus source, while the two soils, limestone, and one expanded shale had only modest sorption capacity. One expanded shale and the fly ash had significant phosphorus sorption. Fly ash is unsuitable for use in a pure form, as a result of its low permeability, but phosphorus sorption on the sand was increased significantly with the incorporation of small amounts of fly ash. Column leaching experiments found that the sand with 2.5 and 5% fly ash and the better expanded shale had linear, non‐equilibrium transport retardation factors of 272, 1618, and 185, with first‐order rate coefficients of 0.153, 0.0752, and 0.113 hour −1, respectively. Desorption experiments showed that the phosphorus sorption on the sand/fly ash mixture is largely nonreversible. Transport simulation assuming a 1‐m‐deep sand/fly ash treatment layer, with 5% of the watershed area, showed that the sand/fly ash filter media could effectively treat 1 mg/L influent for 12 years in a paved watershed and 34 years in a grassed watershed before exceeding Oklahoma's scenic rivers' phosphorus criterion of 0.037 mg/L. Significant phosphorus removal would continue for over 100 years.
Low‐Pressure Catalytic Wet‐Air Oxidation of a High‐Strength Industrial Wastewater Using Fenton's Reagent
Authors: Bıçaksız Zeliha , Aytimur Gülin , Atalay Süheyda
Published: June 2008

Wastewater from the Afyon Alkaloids Factory (Afyon, Turkey) was subjected to low‐pressure catalytic wet‐air oxidation (CWAO) using Fenton's reagent, and the optimal reaction conditions were investigated. The CWAO using Fenton's reagent was applied to the factory effluent, diluted factory effluent, and aerobically pretreated wastewater. To find the optimum quantities of reagents, ferrous iron (Fe +2)‐to‐substrate ratios of 1:10, 1:25, and 1:50 and hydrogen peroxide (H 2O 2)‐to‐Fe +2 ratios of 1, 5, and 10 were investigated, and the treatment was carried out at different temperatures. High chemical oxygen demand (COD) removals were obtained at 50°C, with the Fe +2‐to‐substrate ratio range between 1:10 and 1:25. The change in H 2O 2‐to‐Fe +2 ratios did not cause any considerable effect. Also, the percentages of COD removals were nearly the same, so the ratio H 2O 2:Fe +2:1 is recommended. Aerobic pretreatment seems to be effective. On the other hand, no enhancement was observed in the case of the diluted wastewater.
Experimental Analysis and Modeling of a Stormwater Perlite Filter
Authors: Gironás Jorge , Adriasola José M. , Fernández Bonifacio
Published: June 2008

This paper presents the study of a mixed porous media composed of expanded perlite and a nonwoven needle‐punched geotextile used to reduce the suspended solids load and concentration in urban runoff. Laboratory procedures were designed to quantify the suspended solids removal efficiency and variation in time of filtration rate. Different grain‐size distributions of expanded perlite, diverse suspended solids concentrations, and different hydraulic and geometric conditions were tested to determine the most effective filter media. A dimensionless parameter, termed Global Performance Index (GPI), was developed to reach this objective. Measured data were also used to build a dimensional and a regression model to represent the performance of the filter media mathematically. The theory, derivation, and performance of both models are presented and compared with an existent empirical model. The dimensional model better reproduces the observations, becoming a useful tool for the design, operation, and evaluation of commercial porous media filters.
Some Assembly Required: The Latourian Collective and the Banal Work of Technical and Professional Communication
Authors: Rivers Nathaniel A.
Published: June 2008

In this article, the author uses the critical vocabulary developed by Bruno Latour in his recent work Politics of Nature to offer an alternative way for technical and professional communicators to approach and articulate their work. Using the Discovery Channel's Mythbusters to explore Latour's vocabulary, the author argues that positioning technical and professional communication as more than transmitting and translating, but instead as the collecting of articulated propositions about the common world in service of the common good, thoroughly grounds its practice in rhetorical theory. Such a positioning also ascribes value to technical and professional communication without reinscribing the false dichotomy between science and politics.
Cruel Theory? The Struggle for Prestige and its Consequences in Academic Technical Communication
Authors: Moore Patrick
Published: June 2008

Some struggles for prestige in academic technical communication are self-defeating and wasteful because of the clash between the material (or positive-sum) economy of the workplace and the positional (or zero-sum) economy of the academy. Some professors of technical communication create disrespect for themselves and their specialities because they create degrading representations of working people and their artifacts, they promote impossible standards, and they advance discredited or misleading theories. More profitable approaches to gaining prestige for academic technical communication include recognizing that not everyone can be the top person in the positional economy, studying works on the economics of prestige, and promoting the genuinely good works that already exist in academic technical communication.
Breaking Professional Boundaries: What the MacCrate Report on Lawyering Skills and Values Means for TPC Programs
Authors: Todd Jeff
Published: June 2008

In 1992, the American Bar Association released the MacCrate Report, which listed the ten skills and four professional values that all attorneys need and critiqued law schools and state bars for not doing enough to teach and encourage the development of these skills and values. In response, law schools have significantly increased the skills-based components in their curricula, and most state bar exams now include a performance test. Technical and Professional Communication (TPC) programs already provide substantial instruction in all of the skills and values described in the MacCrate Report; further, an education in TPC prepares graduates to excel in law school and on the bar exam. This knowledge offers opportunities for growth if educators, administrators, and scholars take steps to encourage students to consider not only writing for but also joining in the legal profession.
Contextualize Technical Writing Assessment to Better Prepare Students for Workplace Writing: Student-Centered Assessment Instruments
Authors: Yu Han
Published: June 2008

To teach students how to write for the workplace and other professional contexts, technical writing teachers often assign writing tasks that reflect real-life communication contexts, a teaching approach that is grounded in the field's contextualized understanding of genre. This article argues to fully embrace contextualized literacy and better teach workplace writing, technical writing teachers also need to contextualize how they assess student writing. To this end, this article examines some of workplaces' best assessment practices and critically integrates them into an introductory technical writing classroom through a method called student-centered assessment instruments. This method engages students, as workplaces engage employees, in the assessment process to identify local requirements for writing tasks. Aligned with theory and practice, this method is not only an effective classroom assessment method, but becomes an integrated part of students' genre-learning process within and beyond the classroom.
ALEXITHYMIA AMONG STUDENTS AND PROFESSIONALS IN FUNCTION OF DISCIPLINES
Authors: Bouchard Geneviève
Published: June 2008

This study was aimed at investigating if students and professionals in helping relationships were less alexithymic than those in nonhelping relationships and if professionals were less alexithymic than students. The study was also aimed at examining if the pattern of results for alexithymia
could be reproducible for psychological distress. The 270 individuals (undergraduates and professionals) completed the Toronto Alexithymia Scale (Bagby, Parker, & Taylor, 1994), the Psychiatric Symptom Index (Ilfeld, 1976), and a measure of social desirability (DS36; Tournois, Mesnil,
& Kop, 2000). As hypothesized, results showed that alexithymia was higher among the nonhelping relationship group than among the helping relationship group and decreased as vocational maturity increased. Most importantly, the magnitude of change was similar for both groups. A distinct
pattern of results was observed for psychological distress.
EMOTIONAL INTELLIGENCE AND SELF-EFFICACY IN A SAMPLE OF ITALIAN HIGH SCHOOL TEACHERS
Authors: Fabio Annamaria Di , Palazzeschi Letizia
Published: June 2008

The aim in this study was to further analyze the construct of emotional intelligence and its relation to occupational self-efficacy in a sample of Italian teachers. The Italian version of the Bar-On Emotional Quotient Inventory: Short (Bar-On, 2002) and the Ohio State Teacher Efficacy
Scale (Tschannen-Moran & Woolfolk-Hoy, 2001) were administered to 169 participants. Significant differences in emotional intelligence emerged with respect to age. In comparison to females, males obtained higher scores in the intrapersonal dimension, while women scored higher on the interpersonal
dimension. Teacher self-efficacy was best explained by the intrapersonal dimension. The study indicates both a need for further analysis of the emotional intelligence of teachers and new areas of possible research.
AN EVALUATION OF EXPLANATION EFFECTS ON CONSUMER PERCEPTIONS
Authors: Lin Chia-Yen
Published: June 2008

Previous studies in organization theory have shown that advance notice for an event, such as job termination, is key in determining reactions to the event. Based on ANOVA, the authors demonstrate the positive effects for stores of providing advance explanations to customers, especially
in situations with outcomes unfavorable to the customer. The analysis reveals that providing an explanation will result in higher justice perception, especially in the type of justification. Stores can adopt this low-cost idea of providing explanations to enhance the justice perception of
their customers, and to maintain customer relationships, satisfaction, and loyalty. Implications and directions for future research are also discussed.
PSYCHOLOGICAL PROBLEMS AMONG AID WORKERS OPERATING IN DARFUR
Authors: Musa Saif Ali , Hamid Abdalla A. R. M.
Published: June 2008

Aid workers operating in war zones are susceptible to mental health problems that could develop into stress and acute traumatic stress. This study examined the relationships between burnout, job satisfaction (compassion satisfaction), secondary traumatic stress (compassion fatigue),
and distress in 53 Sudanese and international aid workers in Darfur (mean age = 31.6 years). Measures used were the Professional Quality of Life Questionnaire (ProQOL; Stamm, 2005), the Relief Worker Burnout Questionnaire (Ehrenreich, 2001), and the General Health Questionnaire (Goldberg &
Williams, 1991). Results showed that burnout was positively related to general distress and secondary traumatic stress, and negatively related to compassion satisfaction. Sudanese aid workers reported higher burnout and secondary traumatic stress than did international workers. Results are
discussed in light of previous findings. It was concluded that certain conditions might increase aid workers' psychological suffering and relief organizations need to create positive work climates through equipping aid workers with adequate training, cultural orientation, and psychological
support services.
THE EFFECTS OF EMOTIONS ON VARIETY-SEEKING BEHAVIOR
Authors: Chuang Shih-Chieh , Kung Chaang-Yung , Sun Ya-Chung
Published: June 2008

A study with 124 subjects demonstrated that people are likely to include more variety in their consumption decisions when they are induced to a negative emotion than when they are induced to a positive emotion. This phenomenon is explained by emotion-maintenance theory.
INFLUENCE OF FAMILY AND ENVIRONMENT ON STUDENTS' OCCUPATIONAL CHOICES AND EXPECTATIONS OF THEIR PROSPECTIVE UNIVERSITIES
Authors: Ozdemir Nesrin , Hacifazlioglu Ozge
Published: June 2008

This study was focused mainly on students' expectations of their prospective universities, and the question of whether or not family background or social status affect their career decisions was investigated. The sample consisted of 2,459 students in their final year at high school
from 17 different provinces and 182 high schools all around Turkey. Results show that parents and environment had a great influence on students' occupational preferences. It was also found that students' expectations of universities varied greatly according to their social status
and family income.
AN ARTIFICIAL NEURAL NETWORK APPROACH TO HOTEL EMPLOYEE SATISFACTION: THE CASE OF CHINA
Authors: Tian Xizhou , Pu Yongjian
Published: June 2008

At present, the hotel employment sector in China has a high rate of employee turnover compared to other services. This is not unlike other countries. The reason for the turnover among hotel employees may be lower worker satisfaction resulting in decreased – or no – loyalty
to employers. This study was based on an Artificial Neural Network (ANN). The factors influencing employee satisfaction were examined and the impacts of demographic characteristics on hotel employee satisfaction were analyzed. Results show that hotel employee satisfaction in China is low,
hotel employee satisfaction differs by age and gender, and that professional development opportunities for employees and the long-term growth prospects of the hotels themselves are the most important contributors to employee satisfaction. On the basis of these findings, several recommendations
for improving employee satisfaction, thereby sustaining the long-term economic health of China's hospitality industry, are provided.
OPTIMISM AND PESSIMISM IN KUWAITI AND OMANI UNDERGRADUATES
Authors: Alansari Bader M. , Kazem Ali M.
Published: June 2008

In this study we investigated cultural differences and correlates of optimism and pessimism in Kuwaiti (n = 600) and Omani (n = 600) undergraduates. All respondents completed the Arabic Scale of Optimism and Pessimism (ASOP; Abdel-Khalek & Alansari, 1995), the Beck
Depression Inventory (BDI-II; Beck, Steer, & Brown, 1996), and the Kuwait University Anxiety Scale (KUAS; Abdel-Khalek, 2000). The ASOP displayed good internal consistency, a meaningful factorial structure and interpretable factors in both countries. It was found that optimism correlated
negatively with the above scales, while the correlations of pessimism were positive, indicating the convergent validity of the ASOP. The Kuwaiti mean score on optimism was significantly lower than the mean of their Omani counterparts, and no significant cultural differences were found for
pessimism.
THE RELATIONSHIP BETWEEN THINKING STYLES AND LEVEL OF EXTERNALITY: A STUDY Of TURKISH FEMALE PRESCHOOL STUDENT TEACHERS
Authors: Palut Birsen
Published: June 2008

The relationship between thinking styles and level of externality is examined in this study in which 108 female preschool student teachers at Marmara University participated. The participants responded to the Thinking Style Inventory (TSI; Sternberg & Wagner, 1992) based on Sternberg's
theory of mental self-government and Rotter's Internal-External Locus of Control Scale (RIELS; Rotter, 1966). The results revealed a close correspondence between thinking styles and level of externality. The findings showed that level of externality is negatively associated with legislative,
judicial, hierarchic, global, and liberal thinking styles. The implications are discussed in detail.
HEADTEACHERS' LEADERSHIP BEHAVIOR AND PROBLEM-SOLVING SKILLS: A COMPARATIVE STUDY
Authors: Izgar Hüseyin
Published: June 2008

In this research, the relationship between headteachers' leadership behaviors and problem-solving skills was investigated. The sample comprised 268 headteachers, 53 female and 215 male. The research instruments used were the Leadership Behavior Scale of Turkish Public Administration
(Ergun, 1981) and the Problem Solving Inventory (Heppner & Peterson, 1982). The data were analyzed using the independent t test, variance analysis, Tukey test and correlation test. The results revealed: 1) that there was no significant difference according to gender in the leadership
behavior subscale, 2) that there was a significant difference between headteachers' leadership behavior and the type of school at which they were employed, and 3) that there was a significant relationship between headteachers' leadership behavior and problem-solving skills.
PARENTAL REARING ATTITUDES AND HEALTH-RELATED LIFESTYLE OF UNIVERSITY STUDENTS
Authors: Toda Masahiro , Kawai Tomoko , Takeo Keiko , Rokutan Kazuhito , Morimoto Kanehisa
Published: June 2008

Using a written questionnaire survey of 200 first-year university students, we investigated associations between parental rearing attitudes and health-related lifestyle. Participants completed the Parental Bonding Instrument (PBI; Parker, Tupling, & Brown, 1979) and the Health Practice Index (HPI; Hagihara & Morimoto, 1991). We found that more female respondents with unhealthy lifestyles perceived their parents as having been overprotective. No such correlation was found for male respondents. These findings suggest that, particularly for females, health-related lifestyle may be related to perceived parental rearing attitudes. By contrast, for males, depression correlated with low maternal care or overprotection.
Analysis of the ReSuMe Learning Process For Spiking Neural Networks
Authors: Ponulak Filip
Published: June 2008

Analysis of the ReSuMe Learning Process For Spiking Neural Networks

In this paper we perform an analysis of the learning process with the ReSuMe method and spiking neural networks (Ponulak, 2005; Ponulak, 2006b). We investigate how the particular parameters of the learning algorithm affect the process of learning. We consider the issue of speeding up the adaptation process, while maintaining the stability of the optimal solution. This is an important issue in many real-life tasks where the neural networks are applied and where the fast learning convergence is highly desirable.
Towards Spike-Based Speech Processing: A Biologically Plausible Approach to Simple Acoustic Classification
Authors: Uysal Ismail , Sathyendra Harsha , Harris John
Published: June 2008

Towards Spike-Based Speech Processing: A Biologically Plausible Approach to Simple Acoustic Classification

Shortcomings of automatic speech recognition (ASR) applications are becoming more evident as they are more widely used in real life. The inherent non-stationarity associated with the timing of speech signals as well as the dynamical changes in the environment make the ensuing analysis and recognition extremely difficult. Researchers often turn to biology seeking clues to make better engineered systems, and ASR is no exception with the usage of feature sets such as Mel frequency cepstral coefficients, which employ filter banks similar to cochlear filter banks in frequency distribution and bandwidth. In this paper, we delve deeper into the mechanics of the human auditory system to take this biological inspiration to the next level. The main goal of this research is to investigate the computation potential of spike trains produced at the early stages of the auditory system for a simple acoustic classification task. First, various spike coding schemes from temporal to rate coding are explored, together with various spike-based encoders with various simplicity levels such as rank order coding and liquid state machine. Based on these findings, a biologically plausible system architecture is proposed for the recognition of phonetically simple acoustic signals which makes exclusive use of spikes for computation. The performance tests show superior performance on a noisy vowel data set when compared with a conventional ASR system.
Model Based Analysis of Signaling Pathways
Authors: Śmieja Jarosław
Published: June 2008

Model Based Analysis of Signaling Pathways

The paper is concerned with application of mathematical modeling to the analysis of signaling pathways. Two issues, deterministic modeling of gene transcription and model-driven discovery of regulatory elements, are dealt with. First, the biological background is given and the importance of the stochastic nature of biological processes is addressed. The assumptions underlying deterministic modeling are presented. Special emphasis is put on describing gene transcription. A framework for including unknown processes activating gene transcription by means of first-order lag elements is introduced and discussed. Then, a particular interferon-β induced pathway is introduced, limited to early events that precede activation of gene transcription. It is shown how to simplify the system description based on the goals of modeling. Further, a computational analysis is presented, facilitating better understanding of the mechanisms underlying regulation of key components in the pathway. The analysis is illustrated by a comparison of simulation and experimental data.
A New Approach to Image Reconstruction from Projections Using a Recurrent Neural Network
Authors: Cierniak Robert
Published: June 2008

A New Approach to Image Reconstruction from Projections Using a Recurrent Neural Network

A new neural network approach to image reconstruction from projections considering the parallel geometry of the scanner is presented. To solve this key problem in computed tomography, a special recurrent neural network is proposed. The reconstruction process is performed during the minimization of the energy function in this network. The performed computer simulations show that the neural network reconstruction algorithm designed to work in this way outperforms conventional methods in the obtained image quality.
Segmentation of Breast Cancer Fine Needle Biopsy Cytological Images
Authors: Hrebień Maciej , Steć Piotr , Nieczkowski Tomasz , Obuchowicz Andrzej
Published: June 2008

Segmentation of Breast Cancer Fine Needle Biopsy Cytological Images

This paper describes three cytological image segmentation methods. The analysis includes the watershed algorithm, active contouring and a cellular automata GrowCut method. One can also find here a description of image pre-processing, Hough transform based pre-segmentation and an automatic nuclei localization mechanism used in our approach. Preliminary experimental results collected on a benchmark database present the quality of the methods in the analyzed issue. The discussion of common errors and possible future problems summarizes the work and points out regions that need further research.
Time-Optimal Boundary Control of an Infinite Order Parabolic System with Time Lags
Authors: Kowalewski Adam , Krakowiak Anna
Published: June 2008

Time-Optimal Boundary Control of an Infinite Order Parabolic System with Time Lags

In this paper the time-optimal boundary control problem is presented for a distributed infinite order parabolic system in which time lags appear in the integral form both in the state equation and in the boundary condition. Some specific properties of the optimal control are discussed.
Fractional Positive Continuous-Time Linear Systems and Their Reachability
Authors: Kaczorek Tadeusz
Published: June 2008

Fractional Positive Continuous-Time Linear Systems and Their Reachability

A new class of fractional linear continuous-time linear systems described by state equations is introduced. The solution to the state equations is derived using the Laplace transform. Necessary and sufficient conditions are established for the internal and external positivity of fractional systems. Sufficient conditions are given for the reachability of fractional positive systems.
Creation of Unequal Error Protection Codes for Two Groups of Symbols
Authors: Kuriata Eugeniusz
Published: June 2008

Creation of Unequal Error Protection Codes for Two Groups of Symbols

This article presents problems of unequal information importance. The paper discusses constructive methods of code generation, and a constructive method of generating asymptotic UEP codes is built. An analog model of Hamming's upper bound and Hilbert's lower bound for asymptotic UEP codes is determined.
Towards Defining a Valid Assessment Criterion of Pronunciation Proficiency in Non-Native English-Speaking Graduate Students
Authors: Isaacs Talia
Published: June 2008

Abstract:

Intelligibility has been widely regarded as an appropriate goal for second language pronunciation teaching. Yet there is no universally accepted definition of intelligibility, nor any field-wide consensus on the best way to measure it. Further, there is little empirical evidence to suggest which pronunciation features are crucial for intelligibility to guide teachers in their instructional choices. This mixed-methods study examines whether intelligibility is an appropriate criterion for assessing pronunciation proficiency in the academic domain. Speech samples of eight non-native English speaking graduate students were elicited using the Test of Spoken English, a standardized test often used to screen international teaching assistants (ITAs). Results of a fine-grained analysis of the speech samples combined with intelligibility ratings of 18 undergraduate science students suggest that intelligibility, though an adequate assessment criterion, is a necessary but not a sufficient condition for international graduate students to instruct undergraduate courses as teaching assistants.
Exploration through Virtual Reality: Encounters with the Target Culture
Authors: O’Brien Mary Grantham , Levy Richard M.
Published: June 2008

Abstract:

This paper presents the results of a study on the use of a virtual reality (VR) world in a German language classroom. After participating in a lesson on the use of commands, students experienced the language and culture through navigation in a VR world. It is argued that this new medium allows for students to be immersed in the target culture and language in ways that are not possible through the use of other media. The results of the study indicate that the virtual world experience enhances students’ awareness of the target culture.
Manufacture of Spinnerets for Synthetic Micro-fibers by LIGA and Micro-injection Molding Technique
Authors: Tseng S.-C. , Shi C.-T.
Published: June 2008

In the past, the capillaries of fiber-spinneret were made by micro drilling or by micro electro-discharge-machining (M-EDM). However, the productivity and uniformity of M-EDM are restricted. Hence, a new approach related to LIGA technique was developed. The micro mold of the capillaries was made by LIGA. Micro plastic cores were then duplicated by micro injection molding. With consequent treatments and electroforming, the spinneret die can be mass produced. Better process conditions for micro molding will be determined by Taguchi's experiment design method. Through a single injection molding cycle, a 48-capillary structure was formed at once. The diameters of each capillary were inspected at three locations along the longitudinal direction carefully. The results show that the accuracy of the diameters of capillaries can be controlled within 200 ± 1 μm.

Capillaries die to spin ∗ and w-shaped micro-fibers were also developed in this work. Thanks to LIGA process, spinnerets with higher aspect ratios (even up to 30) can be achieved more easily. By applying micro injection molding, consequent treatments and electro-forming processes, the spinnerets can be produced in a batch and mass production way. The technology developed here can also be used in the fabrication of Micro-Electro-Mechanical (MEMS) components.
Study of Solid-plug Conveying in a Centrifugal Extruder
Authors: Jing Z. , Daming W. , Kuzyayev I. M. , Weihong C. , Hong X. , Ying L.
Published: June 2008

A new type of polymer processing machine, a centrifugal extruder, is introduced and its performance studied experimentally and analyzed theoretically. Calculations show that by means of appropriate choice of the geometrical parameters of the rotor drum and the rotor speed, the pressure of the solid polymer in the rotor drum can reach a value of several MPa. Theoretical analysis also shows that the most important factors influencing the solid conveying pressure in the rotor drum are the radius and slope angle of the rotor drum, the rotation speed of the rotor drum, the friction factor between the solid polymer and the drum surface, and the density of the polymer. An experimental rotor drum was designed in order to validate the mathematical model used for calculation of the solid conveying pressure in the rotor drum. The results of the experiments show good agreement with the theoretical predictions.
Studying the Effective Thermal Properties of Solids in Extrusion Machinery using a Discrete Particle Simulation Approach
Authors: Moysey P. A. , Cloet K. L. , Thompson M. R.
Published: June 2008

In this paper, both experimental trials and numerical simulations are presented to improve our understanding of the heat transfer within granular polymer beds for systems with and without shear. Both amorphous polymer, polystyrene (PS), and a semi-crystalline polymer, high-density polyethylene (HDPE) of varying particle size from 6 mm to 25 mm were examined. The estimated effective thermal conductivity data from the experimental trials was found by fit to two simple semi-empirical models allowing readers to readily approximate the property based on porosity of the bed and solid thermal properties. Discrete particle simulations, i. e. DEM, were used to recognize the importance of heat transport through the stagnant interstitial gas phase in comparison to particle-particle conduction. The results underscore the importance of including an effective thermal conductivity for granular solids in an extruder when using continuum models.
Polymer-ridge Waveguide Fabrication by Gas-assisted UV Embossing with a Soft Mold
Authors: Cheng F.-S. , Huang P.-Y. , Yang S.-Y.
Published: June 2008

This paper reports a new process for the fabrication of polymer optical waveguides using gas-assisted UV embossing. A polydimethylsiloxane (PDMS) mold with a multimode waveguide array was made by casting a pre-polymer of PDMS against a plastic master of a waveguide array. The plastic master was prepared using gas-assisted hot embossing of polycarbonate (PC) film over a Si mold with the waveguide array. In this study, well-defined patterns with fine roughness for the multi-mode waveguides (125 μm × 80 μm) were successfully fabricated. The residual layer was thin and uniform. The replication quality, surface roughness and optical property of the replicated waveguides were measured and proved satisfactory. The average propagation loss of the waveguides was 0.88 dB/cm at a 1310 nm wavelength. The results indicate that the proposed method is likely to be a promising technique for the fabrication of optical waveguides.
Rapid Fabrication of Microstructures onto Plastic Substrates by Infrared Hot Embossing
Authors: Liu S.-J. , Lin K.-Y. , Li M.-K
Published: June 2008

This paper proposes a rapid fabrication technique of polymeric micro-block arrays using an IR hot embossing process. A pneumatically actuated embossing facility with conventional IR heating was designed, constructed and tested in our laboratory. To mold micro-blocks onto the plastic plates, a silicon mold with an array of micro-block cavities was fabricated by photolithography and deep reactive ion etching. During the embossing process, a PMMA plate was first placed above the mold. A ceramic IR heater was placed above the PMMA plate to heat the mold. The IR passed through the transparent PMMA to reach and heat up the mold surface. After retrieval of the IR heater, the pneumatically actuated embossing facility pressed the plastic plate against the hot master mold. A micro-block array was obtained. The effect of various processing parameters on the replicability of the micro-blocks was investigated. Under the proper processing conditions, the arrays of polymeric micro-blocks, with a dimension of 100 m × 80 μm × 40 μm, could be successfully fabricated. The experimental results in this study suggest that IR heated embossing could provide an effective way of fabricating large-area microstructures onto plastic plates. This would provide significant advantages in terms of a shorter cycle time as well as improved product quality.
Design of Calibrators for Profile Extrusion – Optimizing Multi-step Systems
Authors: Nóbrega J. M. , Carneiro O. S. , Gaspar-Cunha A. , Gonçalves N. D.
Published: June 2008

A computer code, that couples numerical modelling and optimization routines, is described and used to automatically optimize the performance of a multi-step calibration stage of a plastic profile extrusion line. The objective of the optimization process is to minimize two conflicting criteria: final plastic profile average temperature and corresponding distribution standard deviation, both computed at the end of the calibration/cooling stage. The optimization routine uses Multi-Objective Evolutionary Algorithms (MOEA). Having in mind the well-known difficulties in characterizing the interface heat transfer coefficient, the system optimization was performed using different constant values for this parameter.
Techniques for restoring fen vegetation on cut‐away peatlands in North America
Authors: Graf M.D. , Rochefort L.
Published: June 2008

Question: Which restoration measures (reintroduction techniques, reintroduction timing and fertilization) best enable the establishment of fen species on North American cut‐away peatlands?

Location: Rivière‐du‐Loup peatland, southern Québec, Canada.

Methods: In total, eight treatments which tested a combination of two reintroduction techniques, two reintroduction timings and the use of phosphorus fertilization were tested in a field experiment within a completely randomized block design.

Results: Sphagnum transfer, a reintroduction technique commonly used for bog restoration in North America, was effective for establishing Sphagnum and Carex species. The hay transfer method, commonly used for fen restoration in Europe, was much less successful, probably due to questionable viability of reintroduced seeds. The treatments which included light phosphorus fertilization, had a higher Carex cover after three growing seasons. The timing of the reintroductions had no impact on the success of vegetation establishment. However, vegetation reintroduction should be carried out in the spring while the ground is still frozen to minimize other ecological impacts.

Conclusions: The success of the diaspore reintroduction technique on small‐scale units indicates that a large‐scale restoration of fens using this technique is feasible.
Wildlife Tourist Archetypes: Are All Polar Bear Viewers in Churchill, Manitoba Ecotourists?
Authors: Harvey Lemelin Raynald , Smale Bryan
Published: June 2008

Ecotourists have largely been defined in the literature a priori based on their geographic location (e.g., visitors to designated natural areas) and/or exhibited behaviors (e.g., engagement in nature viewing such as bird watching or camping). However, such definitions fail to consider
whether these individuals do indeed embrace the psychological makeup that would qualify them as "real" ecotourists based on ecotourist ideal types. This study derives a profile of wildlife tourists based on their psychographic characteristics as suggested by conceptual definitions of ecotourists
and wildlife tourism in particular. Essentially, the question underlying the study was to determine if all wildlife tourists do, in fact, share those characteristics typically assumed in the literature to be inherent to ecotourism.
Climate Change, Marine Tourism, and Sustainability in the Canadian Arctic: Contributions from Systems and Complexity Approaches
Authors: Dawson Jackie , Maher Patrick T. , Slocombe Scott D.
Published: June 2008

The climate-sensitive tourism industry, including Arctic marine tourism, is expected to be significantly impacted by climate change. The multifaceted impacts of climate change at multiple scales warrant a theoretical framework that is able to effectively examine complex and integrated
relationships. The complex ties between culture, economy, and environment in the Arctic also mean a systems perspective on tourism-related change and sustainability seems highly appropriate. This article outlines some systems approaches to Arctic marine tourism. Key contributions of a systems
framework include reconceptualizing Butler's Tourism Area Life Cycle, providing a framework for describing and understanding the tourism–climate change system, including identifying change influences and dynamics at varied spatial and temporal scales, and informing sustainability planning
and assessment.
Controlled Fabrication of Multitiered Three‐Dimensional Nanostructures in Porous Alumina
Authors: Ho Audrey Yoke Yee , Gao Han , Lam Yee Cheong , Rodríguez Isabel
Published: June 2008

We present the fabrication of multitiered branched porous anodic alumina (PAA) substrates consisting of an array of pores branching into smaller pores in succeeding tiers. The tiered three‐dimensional structure is realized by sequentially stepping down the anodization potential while etching of the barrier layer is performed after each step. We establish the key processing parameters that define the tiered porous structure through systematically designed experiments. The characterization of the branched PAA structures reveals that, owing to constriction, the ratio of interpore distance to the anodization potential is smaller than that for pristine films. This ratio varies from 1.8 to 1.3 nm V−1 depending on the size of the preceding pores and the succeeding tier anodization potential. Contact angle measurements show that the multitiered branched PAA structures exhibit a marked increased in hydrophilicity over two‐dimensional PAA films.
Spectroscopic and thermal characterization of the host–guest interactions between α‐, β‐ and γ‐cyclodextrins and vanadocene dichloride
Authors: Morales Alexis , Weber Ralph T. , Melendez Enrique
Published: June 2008

Host–guest interactions between α‐, β‐ and γ‐cyclodextrins and vanadocene dichloride (Cp2VCl2) have been investigated by a combination of thermogravimetric analysis, differential scanning calorimetry, powder X‐ray diffraction and solid‐state and solution electron paramagnetic resonance (EPR) spectroscopy. The solid‐state results demonstrated that only β‐ and γ‐cyclodextrins form 1:1 inclusion complexes, while α‐cyclodextrin does not form an inclusion complex with Cp2VCl2. The β‐ and γ‐CD–Cp2VCl2 inclusion complexes exhibited anisotropic electron‐51V (I = 7/2) hyperfine coupling constants whereas the α‐CD–Cp2VCl2 system showed only an asymmetric peak with no anisotropic hyperfine constant. On the other hand, solution EPR spectroscopy showed that α‐cyclodextrin (α‐CD) may be involved in weak host–guest interactions in equilibrium with free vanadocene species. Copyright © 2008 John Wiley & Sons, Ltd.
Polyhedral oligomeric silsesquioxane bound fulleropyrrolidines
Authors: Clarke David J. , Matisons Janis G. , Simon George R. , Samoc Marek , Samoc Anna
Published: June 2008

The first reported examples of polyhedral oligomeric silsesquioxane (POSS) cages containing a fulleropyrrolidine species are reported herein. Monosubstituted POSS‐dioxalane species were synthesized through the hydrosilylation of a silyl‐dioxalane with mono‐vinyl substituted POSS. Subsequent deprotection yielded the desired aldehyde functionality. An alternative synthetic pathway, involving the nucleophilic substitution of mono‐benzyl chloride POSS with 4‐hydroxybenzaldehyde yielded the desired aldehyde functionality. Each mono‐aldehyde POSS was then reacted with N‐methylglycine and C60 to yield the desired POSS fulleropyrrolidines. The prepared compounds were characterized by multinuclear NMR, electrospray mass spectrometry, elemental analysis, UV–vis, fluorescence and optical power limiting measurements. Copyright © 2008 John Wiley & Sons, Ltd.
Niobium(V) chloride‐catalyzed synthesis of α‐aminonitriles with simultaneous reaction of aldehydes, amines and trimethylsilyl cyanide
Authors: Majhi Anjoy , Kim Sung Soo , Kim Ho Sub
Published: June 2008

A simple and efficient one‐pot method has been developed for the synthesis of α‐aminonitriles by concurrent reaction of aldehydes, amines and trimethylsilyl cyanide with a catalytic amount of NbCl5 (10 mol%) in CH3CN at room temperature. Copyright © 2008 John Wiley & Sons, Ltd.
Beyond agrification: twenty five years of policy and innovation for non‐food application of renewable resources in the Netherlands
Authors: Bos Harriëtte L. , Slingerland Maja A. , Elbersen Wolter , Rabbinge Rudy
Published: June 2008

The first part of this review describes policy developments in the Netherlands since the 1980s around innovations for non‐food application of renewable resources. Next, these developments are analyzed using the Strategic Niche Management (SNM) theory. The drivers at the regime level and the quality of the processes at the niche level have increased considerably in the last number of years. The trend toward a much wider use of renewable resources for non‐food applications thus seems more robust than it was in the previous century. From the SNM analysis, we derive a number of recommendations for policy‐makers active in this field. We also present a previously unpublished stakeholder study performed in 2000 on the factors of success for innovations in this field, and derive from this study recommendations for innovators active in the field. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd
Risk factors for development of desmoid tumours in familial adenomatous polyposis
Authors: Lefevre J H , Parc Y , Kernéis S , Goasguen N , Benis M , Parc R , Tiret E
Published: June 2008

Background

Desmoid tumours (DTs) are the primary cause of death of patients with familial adenomatous polyposis (FAP) following restorative proctocolectomy. The aim of this study was to identify risk factors for DT in a French population.

Methods

Clinical data for 442 patients with FAP from 1983 to 2004 were reviewed retrospectively.

Results

A total of 124 DTs were documented in 50 patients (25 female). DT sites were mesenteric (73 tumours), abdominal wall (44) and extra-abdominal (seven). Female patients developed DT earlier than males. Although DTs appeared after colectomy in 34 patients, the type of surgery did not influence the risk of DT. An identified point mutation in the adenomatous polyposis coli (APC) gene after codon 1444 was a significant risk factor (hazard ratio 3·3 (95 per cent confidence interval 1·5 to 7·3)). Belonging to a family affected by DT did not increase the individual's risk in this population.

Conclusion

No risk factor for life-threatening mesenteric DT could meaningfully modify the management of patients with FAP.
Long-term health-related quality of life following surgery for oesophageal cancer
Authors: Djärv T , Lagergren J , Blazeby J M , Lagergren P
Published: June 2008

Background

The aim of the study was to assess health-related quality of life (HRQL) in patients with surgically cured oesophageal cancer.

Methods

A Swedish nationwide cohort of patients undergoing oesophagectomy for cancer between April 2001 and January 2004 was studied prospectively, and compared with a Swedish age- and sex-adjusted reference population. Validated European Organisation for Research and Treatment of Cancer quality of life questionnaires were used to assess HRQL at 6 months and 3 years after surgery. A mean score difference of 10 or more between groups was considered clinically relevant and tested further for statistical significance.

Results

Of 358 patients, 117 (32·7 per cent) survived for at least 3 years. Of these, 87 patients (74·4 per cent) responded to the questionnaires. Six months after surgery, most aspects of HRQL were substantially worse than in the reference population with no improvement at 3 years. Patients alive at 3 years reported significantly poorer role and social function, and significantly more problems with fatigue, diarrhoea, appetite loss, nausea and vomiting, than in the reference population.

Conclusion

HRQL in long-term survivors after oesophagectomy does not improve between 6 months and 3 years after surgery, and is worse than that in a comparable reference population.
Two‐Phase Sequential Simulation of a Fluidized Bed Reformer
Authors: Habibi R. , Hajizadeh S. , Sotudeh‐Gharebagh R. , Mostoufi N.
Published: June 2008

A two‐phase flow model is adapted in order to predict the performance of a fluidized bed reformer using the sequential modular simulator. Since there are physical and chemical phenomena interacting in the reformer, two sub‐models appear to be necessary to describe the overall model. These are the hydrodynamic and reaction sub‐models. The hydrodynamic sub‐model is based on the dynamic two‐phase model and the reaction sub‐model is derived from the literature. In the overall model, the bed is divided into several sections. At each section, the flow of the gas is considered as plug flow through the bubble phase and to be perfectly mixed through the emulsion phase. Two sets of experimental data from the literature at different hydrodynamic regimes were used in order to validate the proposed model. A close agreement was observed between the model predictions and the experimental data. The model proposed in this work may be used as a framework for the development of sophisticated models for non‐ideal reactors inside process simulators.
Parameter Sensitivity Analysis of a Spouted Bed
Authors: Woinaroschy A. , Jinescu G. , Petrescu M.
Published: June 2008

A three‐layer neural network, based on 192 sets of experimental data obtained by the authors, was built in order to simulate the influence of four main process parameters on the minimum and stationary spouting velocity and on the pressure drop in a spouted bed. The simulations with the neural net are in good agreement with experimental learning data, and the overall average absolute error is 5.43 %. The neural net was used in the framework of a Monte Carlo simulation using CRYSTAL BALL®. The result of 100,000 trials revealed the percentage contributions of the process parameters to the variance of the selected state variables. Since there is significant uncertainty concerning the design equations of spouted beds, the results of this work should be useful for the design of such devices.