bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of feeding fermented fish on egg cholesterol content in hens
Authors: LOH Teck‐Chwen , LAW Fang‐Ling , GOH Yong‐Meng , FOO Hooi‐Ling , ZULKIFLI Idrus
Published: October 2008

This study was conducted to investigate the effects of feeding fermented fish (FF) to layers on laying performance, and polyunsaturated fatty acid and cholesterol levels in eggs and plasma. A total of 96, 13‐week‐old Babcock B380 pullets were used in this study. They were randomly assigned to four numerically equal groups with eight replicates per treatment, three birds per replicate. All the birds were housed in individual cages. The dietary treatments were: Control diet, without FF; FF3 diet containing 3% (w/w) FF, FF6 diet containing 6% (w/w) FF and FF9 diet containing 9% (w/w) FF. The study was carried out for 16 weeks inclusive of two weeks of adjustment. Weekly feed intake and egg production were recorded. Blood plasma cholesterol and fatty acid profiles were assayed at the end of the experiment. FF did not enhance (P > 0.05) egg mass but (P < 0.05) decreased egg weight slightly. However, egg yolk cholesterol and plasma cholesterol concentrations were reduced (P < 0.05) by FF. The n‐6:n‐3 fatty acids ratio in the egg yolk (Control = 7.9, FF9 = 6.2) and plasma (Control = 10.6, FF9 = 6.2) were decreased by feeding FF. Moreover, FF was able to increase (P < 0.05) the docosahexaenoic acid (DHA) concentrations in egg yolk and plasma. In conclusion, this study demonstrated that FF increased DHA and reduced egg yolk cholesterol in poultry eggs.
The degree of tongue‐coating reflects lingual motor function in the elderly
Authors: Kikutani Takeshi , Tamura Fumiyo , Nishiwaki Keiko , Suda Makio , Kayanaka Hisae , Machida Reiko , Yoshida Mitsuyoshi , Akagawa Yasumasa
Published: October 2008

Objectives:  The aim of this study was to examine the relation between the degree of tongue‐coating and oral function.

Background:  Tongue‐coating is a moss‐like deposit which forms over the tongue surface, and includes micro‐organisms, food residues, and abrasive epithelia. It is considered that motor function of the tongue and lips and saliva secretion decrease in the aged and have some effect on the accumulation of tongue‐coating. Although saliva secretion has been reported as a factor amongst these oral functions in contributing to tongue‐coating, the correlation with the motor function of oral structures is unknown.

Subjects and methods:  The factors that contribute to the accumulation of tongue‐coating were examined in 48 subjects of advanced age (mean age 80.8 ± 7.8 years) with no severe levels of periodontal disease. Changes in the degree of tongue‐coating were also examined after oral functional training in these subjects. The frequency of oral cleaning, status of oral hygiene, motor function of the tongue, and masticatory performance were examined as potential factors associated with the degree of coating.

Results:  The results showed that tongue pressure and the frequency of oral diadochokinesis measured by pronouncing the single syllable ‘ka’ as an indicator were statistically significantly correlated with the degree of tongue‐coating. Several factors in oral function improved with training, and also the degree of tongue‐coating decreased in 27 subjects.

Conclusion:  These results suggest a correlation between the degree of tongue‐coating and a reduction in lingual motor function and, in addition, possible improvement in level of coating by functional training of the tongue.
Maxillary complete denture movement during chewing in mandibular removable partial denture wearers
Authors: De Souza Raphael Freitas , Marra Juliê , Pero Ana Carolina , Regis Rômulo Rocha , Compagnoni Marco Antonio , Paleari André Gustavo
Published: October 2008

Objectives:  To evaluate the pattern of maxillary complete denture movement during chewing for free‐end removable partial dentures (RPD) wearers, compared to maxillary and mandibular complete denture wearers.

Materials and methods:  Eighteen edentulous participants (group I) and 10 volunteers with bilateral posterior edentulous mandibles (group II) comprised the sample. Measures of mean denture movement and its variability were obtained by a kinesiographic instrument K6‐I Diagnostic System, during the mastication of bread and a polysulphide block. Data were analysed using two‐way anova (α = 0.05).

Results:  Upper movement during chewing was significantly lower for group II, regardless of the test food. The test food did not influence the vertical or lateral position of the denture bases, but more anterior dislocation was found when polysulphide blocks were chewed. Group II presented lower intra‐individual variability for the vertical axis. Vertical displacement was also more precise with bread as a test food.

Conclusion:  It can be concluded that mandibular free‐end RPD wearers show smaller and more precise movements than mandibular complete denture wearers.
Effect of different repair techniques on the accuracy of repositioning the fractured denture base
Authors: Goiato Marcelo Coelho , Pesqueira Aldiéris Alves , Vedovatto Eduardo , Dos Santos Daniela Micheline , Filho Humberto Gennari
Published: October 2008

Objective:  This study investigated the efficacy of different techniques for the union of fragments of a denture before repair and on the accuracy of the reposition.

Materials and methods:  For this study, 20 maxillary dentures made with Lucitone 550 heat‐cured resin were used. Points were determined with a scanner on the cusp of the teeth, as a measurement of the segments. After digitisation, each model was exported to the AUTOCAD R 14 program and two‐dimensional measurements of the distances between the marked points were made. After the initial analysis, the dentures were fractured into two segments using an impact test machine. For the repair, maxillary dentures were divided into two groups; in the first, the repair was carried out using Kerr’s sticky wax and in the second group, Super Bonder was used to join the fragments, with subsequent inclusion of DENTSPLY® Repair Material resin. After the repair, the points of the maxillary dentures were measured again. The numerical values obtained were tabulated to compare the measurements before fracture and after the repair. For statistical analysis, analysis of variance was employed, using a single factor and double factor, followed by the Tukey test with a reliability of 95%.

Results:  The results demonstrated a statistically significant difference between the materials used to join the dentures for repair, where the dentures were joined with sticky wax presented a larger variation in the distances between the points.

Conclusion:  The variation in distances between the points is influenced by the agent of repair.
Visual behavior differences by clinical experience and alarming sound during infusion pump operation
Authors: KATAOKA Jun , SASAKI Minako , KANDA Katsuya
Published: October 2008

Aim:  The purposes of this study are to describe the occurrence of long fixation in view points during infusion pump operation and to examine if there are any differences in the visual behavior between students and nurses or between operating the infusion pump with and without an alarming sound.

Methods:  The participants consisted of six nursing students and three nurses with clinical experience. In a simulated patient room, the participants were equipped with eye trackers and asked to perform two scenarios of infusion pump operation: changing the i.v. tubing position and the air bubble alarm. The eye movement indicators were analyzed statistically with two‐way ANOVA (clinical experience and the alarming sound were the fixed factors).

Results:  Long fixations appeared frequently at the critical part of the infusion pump operation. The students significantly fixated more frequently and had more long fixations than the nurses. In particular, the students frequently fixated to the manual roller clamp. The eye movement indicators were not significantly different between the two scenarios, but the air bubble alarm scenario had a larger ratio of time fixating to the i.v. tubing and a smaller ratio of time fixating to the patient.

Conclusion:  In this study, a large difference could be seen in the comparison of visual behavior by clinical experience. It was clear that the students carefully tried to check each critical point as they were not used to infusion pump operation. It also was found that, although the nurses had relatively consistent eye movement, the students did not grasp the checkpoints and the positions of fixation were dispersed easily as a consistent nursing procedure had not been established.
Religion as Represented in the Art of the Ancient Near East
Authors: Ataç Mehmet‐Ali
Published: October 2008

This essay looks at matters of religion in the art of the ancient Near East both from the point of view of religion as subject matter in the imagery of works of art, and religion in its wider sense that includes philosophical ideas of a sacral character that permeate the rationale of artistic production. In the first half of the essay, the discussion is centered on the way religion has been viewed and treated in the scholarly literature on the art of ancient Mesopotamia. Then follows a selective historical survey of questions and debates pertaining to religion and religious themes that have dominated the field of the history of ancient Near Eastern art.
The Neural Mechanisms of Coreference
Authors: Ledoux Kerry , Camblin C. Christine
Published: October 2008

Coreference (the mechanism by which two linguistic expressions are taken to refer to the same entity in the world) is a universal and essential feature of discourse. Without this tool, our ability to comprehend language would be severely impaired. Due to their central role in discourse comprehension, the processes by which coreference is established have been the focus of numerous behavioral studies. In this article, we review studies that build upon that body of work by employing the event‐related potential technique to elucidate the neuronal bases underlying the representation and processing of discourse. We include in our review studies that violate the formal constraints on the establishment of coreference described by linguistic theory; studies that examine the relative ease or difficulty of establishing coreference under different conditions as predicted by processing models; and studies that examine the modulation of lexico‐semantic processing (such as priming) by processes associated with the establishment of coreference. Additionally, we discuss the implications of this research for models of coreference.
How Infant Speech Perception Contributes to Language Acquisition
Authors: Gervain Judit , Werker Janet F.
Published: October 2008

Perceiving the acoustic signal as a sequence of meaningful linguistic representations is a challenging task, which infants seem to accomplish effortlessly, despite the fact that they do not have a fully developed knowledge of language. The present article takes an integrative approach to infant speech perception, emphasizing how young learners’ perception of speech helps them acquire abstract structural properties of language. We introduce what is known about infants’ perception of language at birth. Then, we will discuss how perception develops during the first 2 years of life and describe some general perceptual mechanisms whose importance for speech perception and language acquisition has recently been established. To conclude, we discuss the implications of these empirical findings for language acquisition.
Reflectance Confocal Microscopy for In Vivo Skin Imaging†
Authors: Calzavara‐Pinton Piergiacomo , Longo Caterina , Venturini Marina , Sala Raffaella , Pellacani Giovanni
Published: October 2008

Reflectance confocal microscopy (RCM) is a novel noninvasive technique for “in vivo” examination of the skin. In a confocal microscope, near‐ infrared light from a diode laser is focused on a microscopic skin target. As this light passes between cellular structures having different refraction indexes, it is naturally reflected, and this reflected light is then captured and recomposed into a two‐dimensional gray scale image by computer software. Focusing the microscope (adjusting the focal point on the z‐axis) allows images to be obtained of different levels within the skin. Commercially available microscope systems of this type can create images with enough detail for use in histological analysis. The first investigations using these microscopes served to identify the appearance of the various cell populations living in the different layers of normal skin. Today, the main interest has become focused on the use of these microscopes as a diagnostic tool: a means of investigating benign and malignant tumors of melanocytes and keratinocytes, and, more importantly, the findings of this field of study can be used to develop a diagnostic algorithm which would be not only highly sensitive but specific as well. The aim of the paper is to provide an updated literature review and an in‐depth critique of the state‐of‐the‐art of RCM for skin cancer imaging with a critical discussion of the possibilities and limitations for clinical use.
Structure–Function of the Cytochrome b6f Complex†
Authors: Baniulis D. , Yamashita E. , Zhang H. , Hasan S. S. , Cramer W. A.
Published: October 2008

The structure and function of the cytochrome b6 f complex is considered in the context of recent crystal structures of the complex as an eight subunit, 220 kDa symmetric dimeric complex obtained from the thermophilic cyanobacterium, Mastigocladus laminosus, and the green alga, Chlamydomonas reinhardtii. A major problem confronted in crystallization of the cyanobacterial complex, proteolysis of three of the subunits, is discussed along with initial efforts to identify the protease. The evolution of these cytochrome complexes is illustrated by conservation of the hydrophobic heme‐binding transmembrane domain of the cyt b polypeptide between b6 f and bc1 complexes, and the rubredoxin‐like membrane proximal domain of the Rieske [2Fe‐2S] protein. Pathways of coupled electron and proton transfer are discussed in the framework of a modified Q cycle, in which the heme cn, not found in the bc1 complex, but electronically tightly coupled to the heme bn of the b6 f complex, is included. Crystal structures of the cyanobacterial complex with the quinone analogue inhibitors, NQNO or tridecyl‐stigmatellin, show the latter to be ligands of heme cn, implicating heme cn as an n‐side plastoquinone reductase. Existing questions include (a) the details of the shuttle of: (i) the [2Fe‐2S] protein between the membrane‐bound PQH2 electron/H+ donor and the cytochrome f acceptor to complete the p‐side electron transfer circuit; (ii) PQ/PQH2 between n‐ and p‐sides of the complex across the intermonomer quinone exchange cavity, through the narrow portal connecting the cavity with the p‐side [2Fe‐2S] niche; (b) the role of the n‐side of the b6 f complex and heme cn in regulation of the relative rates of noncyclic and cyclic electron transfer. The likely presence of cyclic electron transport in the b6 f complex, and of heme cn in the firmicute bc complex suggests the concept that hemes bn‐cn define a branch point in bc complexes that can support electron transport pathways that differ in detail from the Q cycle supported by the bc1 complex.
Long‐term UVB Irradiation Affects the Immune Functions of Carp (Cyprinus carpio) and Rainbow Trout (Oncorhynchus mykiss)
Authors: Markkula Eveliina , Salo Harri M. , Rikalainen Kaisa , Jokinen Ilmari E.
Published: October 2008

The effects of long‐term, low‐dose ultraviolet B (UVB) radiation on immune functions of two fish species representing different taxonomic groups, carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss), were assessed in this study. The fish were exposed to 7, 20 or 60 mJ cm−2 UVB three times per week, for 6 weeks. In carp, UVB exposure affected the respiratory burst activity of blood and head kidney phagocytes, differential blood leukocyte counts and blood chemistry. Phytohemagglutinin (PHA)‐stimulated in vitro proliferation responses of blood and head kidney lymphocytes, however, remained unchanged. Rainbow trout tolerated the irradiations with fewer alterations, but significant changes were detected in blood chemistry and hematocrits of the irradiated fish. These results indicate that long‐term exposure to low doses of UVB induces immunomodulation in fish, and that there are species‐specific differences in sensitivity to irradiation.
The Effect of Chronic Exposure to Artificial UVB Radiation on the Survival and Reproduction of Daphnia magna Across Two Generations
Authors: Huebner Judith D. , Loadman Nancy L. , Wiegand Murray D. , Young Donna L. W. , Warszycki Laura‐Anne
Published: October 2008

We examined the effects of daily (chronic) exposure to artificial UVB radiation on the survival and reproduction of Daphnia magna over two generations. Control and experimental animals in each generation (parental and F1) were exposed to 16 h of UVA radiation and photosynthetically active radiation daily. In addition, experimental animals were exposed to 6 h of UVB during the middle of the light period. Survival and reproduction were followed for 12 days for each individual. Survival and production of F1 were significantly lower in the UVB exposed parental generation Daphnia than in controls. F1 exposure to UVB significantly decreased F1 survival and reproduction. Reproduction was lowest in UVB exposed F1 animals whose parents were also exposed to UVB. Adverse effects of UVB on offspring production may be magnified in successive generations suggesting that short‐term experiments could underestimate the impact of increased UVB exposure on populations.
Periosteal release to allow free movement of the trocar for transbuccal mandibular approach: a technical note
Authors: Khawaja N. , Cascarini L. , Matthews N.S.
Published: October 2008

This article describes a useful technique of periosteal release to allow free movement of the trocar during fixation of mandibular fractures via the transbuccal approach.
Modelling cross‐hybridization on phylogenetic DNA microarrays increases the detection power of closely related species
Authors: ENGELMANN JULIA C. , RAHMANN SVEN , WOLF MATTHIAS , SCHULTZ JÖRG , FRITZILAS EPAMEINONDAS , KNEITZ SUSANNE , DANDEKAR THOMAS , MÜLLER TOBIAS
Published: October 2008

DNA microarrays are a popular technique for the detection of microorganisms. Several approaches using specific oligomers targeting one or a few marker genes for each species have been proposed. Data analysis is usually limited to call a species present when its oligomer exceeds a certain intensity threshold. While this strategy works reasonably well for distantly related species, it does not work well for very closely related species: Cross‐hybridization of nontarget DNA prevents a simple identification based on signal intensity. The majority of species of the same genus has a sequence similarity of over 90%. For biodiversity studies down to the species level, it is therefore important to increase the detection power of closely related species. We propose a simple, cost‐effective and robust approach for biodiversity studies using DNA microarray technology and demonstrate it on scenedesmacean green algae. The internal transcribed spacer 2 (ITS2) rDNA sequence was chosen as marker because it is suitable to distinguish all eukaryotic species even though parts of it are virtually identical in closely related species. We show that by modelling hybridization behaviour with a matrix algebra approach, we are able to identify closely related species that cannot be distinguished with a threshold on signal intensity. Thus this proof‐of‐concept study shows that by adding a simple and robust data analysis step to the evaluation of DNA microarrays, species detection can be significantly improved for closely related species with a high sequence similarity.
Pigmentation PAX‐ways: the role of Pax3 in melanogenesis, melanocyte stem cell maintenance, and disease
Authors: Kubic Jennifer D. , Young Kacey P. , Plummer Rebecca S. , Ludvik Anton E. , Lang Deborah
Published: October 2008

Transcription factors initiate programs of gene expression and are catalysts in downstream molecular cascades that modulate a variety of cellular processes. Pax3 is a transcription factor that is important in the melanocyte and influences melanocytic proliferation, resistance to apoptosis, migration, lineage specificity and differentiation. In this review, we focus on Pax3 and the molecular pathways that Pax3 is a part of during melanogenesis and in the melanocyte stem cell. These roles of Pax3 are emphasized during the development of diseases and syndromes resulting from either too much or too little Pax3 function. Due to its key task in melanocyte stem cells and tumors, the Pax3 pathway may provide an ideal target for either stem cell or cancer therapies.
Aniridia: current pathology and management
Authors: Lee Helena , Khan Rizwana , O’Keefe Michael
Published: October 2008

Aniridia is a rare panocular disorder affecting the cornea, anterior chamber, iris, lens, retina, macula and optic nerve. It occurs because of mutations in PAX6 on band p13 of chromosome 11. It is associated with a number of syndromes, including Wilm’s tumour, bilateral sporadic aniridia, genitourinary abnormalities and mental retardation (WAGR) syndrome. PAX6 mutations result in alterations in corneal cytokeratin expression, cell adhesion and glycoconjugate expression. This, in addition to stem‐cell deficiency, results in a fragile cornea and aniridia‐associated keratopathy (AAK). It also results in abnormalities in the differentiation of the angle, resulting in glaucoma. Glaucoma may also develop as a result of progressive angle closure from synechiae. There is cataract development, and this is associated with a fragile lens capsule. The iris is deficient. The optic nerve and fovea are hypoplastic, and the retina may be prone to detachment. Aniridia is a profibrotic disorder, and as a result many interventions – including penetrating keratoplasty and filtration surgery – fail. The Boston keratoprosthesis may provide a more effective approach in the management of AAK. Guarded filtration surgery appears to be effective in glaucoma. Despite our increasing understanding of the genetics and pathology of this condition, effective treatment remains elusive.
Effect of Grouting in Jacket Type Offshore Platforms Pile-Leg Interaction in Nonlinear Range of Deformation
Authors: Honarvar M. R. , Bahaari M. R. , Asgarian B.
Published: October 2008

The annulus between the pile and leg in jacket type offshore platforms may be filled with cement grout mainly to reduce horizontal deflections, inhibit corrosion, and increase the energy absorption capacity. This paper discusses an approach, which can be used to demonstrate an enhanced structural performance due to the both presence and lack of grouted piles. The compressive stress-strain response of the grout has been derived from the performed experiments. Having this response, the fiber beam column post-buckling element in the commercial code, DRAIN-3DX, was being used to investigate the behavior of grouted and ungrouted jackets and also the relative pile-leg interaction. It is therefore concluded that in the cases where the existing structure is ungrouted or incompletely grouted, adequate grouting can be considered as a relatively inexpensive method to improve the strength and performance of the structure. In fact, the cement filling of a tubular member increases its overall strength and also provides additional stability. The lateral force-deformation curves are equivalents for the cases where the axial force is less than 30% of the yielding force, Pyielding. However, as the axial force increases, the grouted portal element gradually gives a much better performance compared to the ungrouted element. By increasing the axial force, the lateral hysteretic behavior deteriorates in both grouted and ungrouted cases; however, this deterioration is more severe in the case of an ungrouted portal element.
Quasideterminism Theory of Sea Waves
Authors: Boccotti Paolo
Published: October 2008

The quasideterminism (QD) theory introduces a deterministic wave function (of both space and time) that shows what, most probably, will happen if an exceptionally large wave will occur at some point in a sea storm. This deterministic wave function holds for every configuration of the solid boundary, provided that the wave motion may be regarded as irrotational. This is the main feature of some conceptual novelties of the QD theory. The following invited lecture given at the 2006 OMAE Congress in Hamburg aims to emphasize these conceptual novelties through a fresh overall picture of the theory.
Laterally Loaded Piles With Bulge
Authors: Dührkop Jan , Grabe Jürgen
Published: October 2008

This paper contains several investigations on the behavior of bulged piles. Bulge means the application of vertical steel plates somewhere near the ground surface to improve the lateral bearing capacity. The results of small scale tests in sand are illustrated, which demonstrate the effectiveness of such bulge. Some theoretical investigations are presented trying to apply standard methods like the p‐y-curve procedure to the design of bulged piles. An outline of possible calculation methods is given. Investigations on two different exemplary pile systems demonstrate the behavior of the bulged structure and give an idea of the advantages of this innovative system.
Reliability Analysis of Marine Platforms Subject to Fatigue Damage for Risk Based Inspection Planning
Authors: Heredia-Zavoni Ernesto , Silva-González Francisco , Montes-Iturrizaga Roberto
Published: October 2008

The probability of failure of steel jacket platforms subjected to fatigue damage is computed by means of Monte Carlo simulations using limit state functions in which wave, wind, and deck loadings are expressed in terms of empirical functions of uncertain maximum wave height. Limit state functions associated with the base shear capacity of the jacket and the shear capacity of the deck legs were used. The sensitivity of the probability of failure to the coefficient of variation of resistance, of wave height, of resistance and loading biases, and to parameters in empirical loading functions, as well as the influence of the reserve strength ratio is analyzed using a simplified limit state function. Results from simulations are compared to those obtained with a formulation that relates the reserve strength ratio to the reliability index. An application to risk based inspection planning for extension of the service life of a platform is given.
Experimental
Investigation of Two Dimensional Motion of an Elastically Supported Cylinder in a
Wake
Authors: Blevins Robert
D. , Saint-Marcoux Jean-Francois , Wu Mason
Published: October 2008

Measurements have been made of two dimensional motion of an elastically supported circular cylinder in the wake of a fixed upstream cylinder. The experiments were made in a water flow channel with 6.35cm(2.5in.) diameter cylinders with a maximum Reynolds number of 77,000. The elastically supported downstream cylinder moves downward and inward toward the centerline of the upstream cylinder’s wake with increasing flow velocity, indicating the presence of a transverse lift force and reduced drag in the wake. These forces can cause the cylinders to clash. The measured motions correlate with the theory.
VIVACE (Vortex Induced Vibration Aquatic Clean Energy): A New Concept in Generation of Clean and Renewable Energy From Fluid Flow
Authors: Bernitsas Michael M. , Raghavan Kamaldev , Ben-Simon Y. , Garcia E. M. H.
Published: October 2008

Any device aiming to harness the abundant clean and renewable energy from ocean and other water resources must have high energy density, be unobtrusive, have low maintenance, be robust, meet life cycle cost targets, and have a 10–20year life. The vortex induced vibration aquatic clean energy (VIVACE) converter—invented by Bernitsas and Raghavan, patent pending through the University of Michigan—satisfies those criteria. It converts ocean/river current hydrokinetic energy to a usable form of energy such as electricity using VIV successfully and efficiently for the first time. VIVACE is based on the idea of maximizing rather than spoiling vortex shedding and exploiting rather than suppressing VIV. It introduces optimal damping for energy conversion while maintaining VIV over a broad range of vortex shedding synchronization. VIV occurs over very broad ranges of Reynolds (Re) number. Only three transition regions suppress VIV. Thus, even from currents as slow as 0.25m∕s, VIVACE can extract energy with high power conversion ratio making ocean/river current energy a more accessible and economically viable resource. In this paper, the underlying concepts of the VIVACE converter are discussed. The designs of the physical model and laboratory prototype are presented. A mathematical model is developed, and design particulars for a wide range of application scales are calculated. Experimental measurements on the laboratory prototype are reported in the sequel paper and used here for preliminary benchmarking.
The Effect of Directionality on Northern North Sea Extreme Wave Design Criteria
Authors: Ewans Kevin , Jonathan Philip
Published: October 2008

The characteristics of hindcast data for extreme storms at a Northern North Sea location are shown to depend on storm direction, reflecting storm strength and fetch variability. Storm peak HS over threshold is modeled using a generalized Pareto distribution, the parameters of which are allowed to vary smoothly with direction using a Fourier form. A directionally varying extreme value threshold is incorporated. The degree of smoothness of extreme value shape and scale with direction is regulated by roughness-penalized maximum likelihood, the optimal value of roughness selected by cross-validation. The characteristics of a 100-year storm peak HS, estimated using the directional model, differ from those estimated when ignoring the directionality of storms. In particular, the extreme right-hand tail of omnidirectional HS100 is longer using the directional model, indicating in this case that ignoring directionality causes underestimation of design criteria. Although storm peak data alone are used for extreme value modeling, the influence of a storm, in directional design sectors other than that containing its storm peak direction, is incorporated by estimating the storm’s directional dissipation directly from the data. An automated approach to selection of directional design sectors is described. Directional design criteria are developed using three different approaches, all consistent with an omnidirectional storm peak HS nonexceedence probability of 0.5. We suggest a risk-cost criterion, which minimizes design cost for a given omnidirectional design specification, as an objective basis for optimal selection of directional criteria.
Solar Thermochemical Water-Splitting Ferrite-Cycle Heat Engines
Authors: Diver Richard B. , Miller James E. , Allendorf Mark D. , Siegel Nathan P. , Hogan Roy E.
Published: October 2008

Thermochemical cycles are a type of heat engine that utilize high-temperature heat to produce chemical work. Like their mechanical work producing counterparts, their efficiency depends on the operating temperature and on the irreversibility of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxide (ferrites) working materials. The design concepts utilize two sets of moving beds of ferrite reactant materials in close proximity and moving in opposite directions to overcome a major impediment to achieving high efficiency—thermal recuperation between solids in efficient countercurrent arrangements. They also provide an inherent separation of the product hydrogen and oxygen and are an excellent match with a high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this paper, the counter-rotating-ring receiver∕reactor∕recuperator solar thermochemical heat engine concept is introduced, and its basic operating principles are described. Preliminary thermal efficiency estimates are presented and discussed. Our results and development approach are also outlined.
Comparative Study of Photocatalytic Degradation Mechanisms of Pyrimethanil, Triadimenol, and Resorcinol
Authors: Araña J. , Fernández Rodríguez C. , Herrera Melián J. A. , González Díaz O. , Pérez Peña J.
Published: October 2008

The photocatalytic degradation of an endocrine disruptor (resorcinol) and of two fungicides (pyrimethanil and triadimenol) has been studied and compared. The effect of pH, oxygen, and H2O2 on the photocatalytic degradation of these compounds has been established. The three organics were analyzed by means of high pressure liquid chromatography (HPLC) and their mineralization by total organic concentration (TOC) measurements. The evolution of the toxicity to Lemna minor of the aqueous solutions of the three organics during their photocatalytic treatment has also been studied. The obtained results have been interpreted according to Fourier transform infrared studies on the interaction of the molecules with the catalyst surface and their reaction mechanisms by gas chromatographpy-mass spectrometry (GC-MS) analyses. The toxicity studies have shown that some intermediates acted as nutrients or toxicity antagonists as negative growth rate inhibitions were obtained. After 30min of reaction, the resorcinol and pyrimethanil solutions were detoxified, although some amount of the organics still remained. In the case of triadimenol, a 92% detoxification was achieved after 60min of reaction. The solar photocatalytic degradations of the pollutants have resulted to be comparable with those obtained with UV lamp. The obtained results suggest that the type of interaction of pyrimethanil and triadimenol with the TiO2 surface decides their degradation mechanism by which the effect of pH, H2O2, and dissolved oxygen is determined. It has also been confirmed that the photocatalytic techniques are very efficient at the detoxification of wastewaters contaminated with these fungicides.
Preliminary Study of the Disinfection of Secondary Wastewater Using a Solar Photolytic-Photocatalytic Reactor
Authors: Hernández-García Héctor , López-Arjona Héctor , Rodríguez Juan Francisco , Enríquez Rosario
Published: October 2008

Our main purpose was to study the disinfection of a secondary wastewater anaerobic effluent by a combined photolytic-photocatalytic continuous reactor using solar irradiation. This reactor had a rectangular section and included back-and-forth-flow internal channels. It comprised two compartments: the first one (6.4l) corresponded to photolytic disinfection with a 1h residence time and the second one (12.8l) corresponded to photocatalytic disinfection with a 2h residence time. The photocatalyst used was Degussa P-25 TiO2 fixed on an ordinary tile. By use of this reactor between 9:00h and 16:00h with a water flow rate of 3.4lh−1, the total coliform concentration diminished by four orders of magnitude, reaching values lower than 102MPN (most probable number)/100ml, which are below the regulation. Even if photolysis was important, this single process did not permit one to obtain an outlet coliform concentration below 103MPN∕100ml; however, it helped to improve the photocatalytic performance. A decrease in chemical oxygen demand (COD) was also observed in the photocatalytic compartment, illustrating an oxidation of organic pollutants. In parallel, batch experiments were carried out to get information about the residence times, the photocatalytic performance of TiO2 fixed on an ordinary tile, and the photolytic effect. The results suggest that this low cost and easy to operate treatment system could be a promising alternative to usual systems for the decrease in COD and the disinfection of domestic wastewaters.
Mesostructured Anatase TiO2 for Visible Light and UV Photocatalysis With Confinement Effect and Semiconductor Coupling
Authors: Bosc Florence , Ayral André , Keller Nicolas , Keller Valérie
Published: October 2008

Hexagonal and cubic mesostructured TiO2 anatase were synthesized by a templating sol-gel method using triblock copolymers as structuring agents, and used as photocatalysts for providing geometrical assistance to a photocatalytic reaction. The visible light and UV photocatalytic removal of gas-phase concentrated toluene (110ppm) within an annular flow-reactor was used as a tool to evidence the benefit to use mesostructured photocatalysts. The coupling of low amounts of WO3 with mesostructured anatase led to high efficiency using visible light and UV activation. The highly positive effect of WO3 on the toluene removal efficiency was attributed to the coupling between TiO2 and WO3 semiconductors, leading to an improved photogenerated charge separation and thus a weaker charge recombination. The hypothesis of a confinement effect of the reactants inside the mesostructured photocatalyst was put forward to explain the photocatalytic performances obtained under visible light and UV activation. This confinement effect would be based on the inner partial pressure concept. It consists of an increase in the partial pressure of the reactants next to the active sites inside the nanometric cavities of the ordered structure, while the apparent macroscopic partial pressures, outside the mesostructure, would remain unchanged. According to a traditional reaction rate law, such an increase results in the increase in the reaction rate. The photon-assisted reaction could be considered as “structure-assisted,” the geometrical assistance being provided by the surrounding ordered TiO2 walls of the mesostructure.
Hydrolysis of Evaporated Zn in a Hot Wall Flow Reactor
Authors: Abu Hamed Tareq , Davidson Jane H. , Stolzenburg Mark
Published: October 2008

Hydrolysis of Zn is investigated as the second step in a ZnO∕Zn redox solar water splitting process. Zinc is evaporated and hydrolyzed with steam in a hot wall flow tubular reactor. The influence of the reactor temperature distribution and residence time on hydrogen conversion was measured for furnace set point temperatures of 1023K and 1073K. The yield of ZnO aerosol was measured in situ using a scanning differential mobility sizer. The composition and morphology of the solid product were characterized with X-ray diffraction and microscopy. Hydrogen conversions of 87–96% at temperatures above zinc saturation are attributed primarily to hydrolysis of zinc(g) at the wall of the reactor at temperatures from 800Kto1077K.
Treatment of Aqueous Solutions Containing Four Commercial Pesticides by Means of TiO2 Solar Photocatalysis
Authors: García-Ripoll A. , Arques A. , Vicente R. , Domenech A. , Amat A. M.
Published: October 2008

Metasystox, Ultracid, Sevnol, and Laition are commercial pesticides, whose active ingredients are, respectively, oxydemethon-methyl, methidathion, carbaryl, and dimethoate. Laboratory scale experiments were carried out to treat solutions of the pure active ingredient and the commercial formulation employing a solar simulator as irradiation source. Degradation of the active ingredient followed in all cases a pseudo-first-order kinetic and rate constants, k, indicated that reaction was faster when the thiophosphate moiety was present. Additives existing in the commercial formulations resulted in an important decrease in the reaction rate, as k values were at least 50% lower than those obtained with the corresponding pure active principle (0.013min−1 for Ultracid and 0.033min−1 for methidathion, 0.011min−1 for Laition and 0.026min−1 for dimethoate, and 0.007min−1 for Sevnol and 0.016min−1 for carbaryl). Important increase in the surface tension was measured in all cases, indicating that the photocatalytic treatment is able to remove the surface active species present in the commercial formulation. Finally, assays based on the inhibition of the respiration of activated sludge indicated a decrease in the toxicity of all four commercial mixtures from initial values in the range 40–80% to achieve complete detoxification when the elimination of the active ingredient is reached.
Design for Upgradability Algorithm: Configuring Durable Products for Competitive Reutilization
Authors: Xing Ke , Belusko Martin
Published: October 2008

Product upgrade, achieved through the improvement of the functionality of reused or remanufactured products, is often accepted as an effective way to attain a competitive reutilization. Design for upgradability (DFU) is a tool that primarily focuses on enhancing a product’s functional as well as physical fitness for ease of upgrade. This paper presents the development of a novel approach and its implementation algorithm for a systematic design of product upgradability. The framework of this approach consists of two major phases––modeling and optimization. Fuzzy logic is used as a tool to facilitate the modeling of a product’s upgradability based on its technical characteristics and the reutilization mode. In the optimization phase, a new DFU optimization program is developed by using genetic algorithm techniques. The objective of a product’s DFU optimization is defined so as to configure/redesign a product for the maximal level of upgradability with minimal associated costs and violations of engineering, economic, and environmental constraints. A case study on a solar heating system is presented to demonstrate the application of the proposed DFU algorithm and its effectiveness in generating optimal configurations for the system, which are reflected as significant improvements in the system’s upgradability, cost efficiency, and overall functionality.
Simulation of Hypoid Gear Lapping
Authors: Jiang Qimi , Gosselin Claude , Masseth Jack
Published: October 2008

In the lapping process of hypoid gears, a gear set is run at varying operating positions and under a light load in order to lap the complete tooth surface. Because of the rolling and sliding motion inherent to hypoid gears, the lapping compound acts as an abrasive and refines the tooth surface to achieve smoothness in rolling action and produce high quality gear sets. In this paper, the lapping process is reproduced using advanced modeling tools such as gear tooth vectorial simulation for the tooth surfaces and reverse engineering to analyze the tooth contact pattern of existing gear sets. Test gear sets are measured using a coordinate measurement machine prior to a special lapping cycle where the position of the gear sets on the lapper does not change, and then are remeasured after lapping in order to establish how much and where material was removed. A wear constant named “wear coefficient” specific to the lapping compound is then calculated. Based on the obtained wear coefficient value, an algorithm for simulating the lapping process is presented. Gear sets lapped on the production line at AAM are used for simulation case studies. Initial results show significant scattering of tooth distortion from tooth to tooth and from gear set to gear set, which makes the simulation process difficult. However, it is possible to predict a confidence range within which actual lapping should fall, thereby opening the door to the optimization of the lapping process.
Nonlinear Identification of Machine Settings for Flank Form Modifications in Hypoid Gears
Authors: Artoni Alessio , Gabiccini Marco , Guiggiani Massimo
Published: October 2008

This paper presents a new systematic method for identifying the values of the machine-tool settings required to obtain flank form modifications in hypoid gears. The problem is given a nonlinear least-squares formulation, and it is solved by the Levenberg–Marquardt method with a trust-region strategy. To test the method, the same ease-off topography was obtained by means of very different sets of machine-tool settings, including a set of only kinematic parameters and a highly redundant set of 17 parameters. In all cases, the goal was achieved in a few iterations, with residual errors well below machining tolerances and, even more importantly, with realistic values of all parameters. Therefore, significant improvements in practical gear design can be achieved by employing the overall proposed procedure.
Design of Grip-and-Move Manipulators Using Symmetric Path Generating Compliant Mechanisms
Authors: Wang N. F. , Tai K.
Published: October 2008

This paper presents the problem formulation and design of compliant grip-and-move manipulators. Each manipulator is composed of two identical path generating compliant mechanisms such that it can grip an object and convey it from one point to another. The integration of both gripping and moving behaviors within a simple mechanism is accomplished by the use of compliant mechanisms, which generate paths that are symmetric. The automated synthesis of these symmetric path generating mechanisms is by a structural topology optimization approach. The problem of topology optimization of continuum structures is solved using a multiobjective genetic algorithm coupled with a morphological representation of geometry that efficiently defines the variable structural geometry upon a finite element grid. A graph-theoretic chromosome encoding together with compatible crossover and mutation operators are then applied to form an effective evolutionary optimization procedure. Two designs have been created and are presented in this paper, and some concluding remarks and future work are put forward.
MG-IVT: An Infinitely Variable Transmission With Optimal Power Flows
Authors: Bottiglione Francesco , Mantriota Giacomo
Published: October 2008

The infinitely variable transmissions (IVTs) allow the transmission ratio to vary with continuity, offering the possibility of also reaching zero values for the transmission ratio and the motion inversion. In this paper an original infinitely variable transmission system is described (MG-IVT). MG-IVT is made up of the coupling of a continuously variable transmission, a planetary gear train, and two ordinary transmissions with a constant transmission ratio. By means of two frontal clutches, the MG-IVT is allowed to get two different configurations. The main purpose is to get the configurations that make the optimal efficiency of the transmission at different transmission ratios. Kinetic characteristics of single component devices are obtained, and the MG-IVT system’s performance is determined by considering how the efficiency of the component devices change as a function of operating conditions. The advantages of the MG-IVT are therefore shown in terms of power and efficiency in comparison to the traditional IVT.