bluuebunny/crossref_metadata_2025 huggingface dataset:
Piecewise-Linear Neural Networks and Their Relationship to Rule Extraction from Data
Authors: Holeňa Martin
Published: September 2006

This article addresses the topic of extracting logical rules from data by means of artificial neural networks. The approach based on piecewise linear neural networks is revisited, which has already been used for the extraction of Boolean rules in the past, and it is shown that this approach can be important also for the extraction of fuzzy rules. Two important theoretical properties of piecewise-linear neural networks are proved, allowing an elaboration of the basic ideas of the approach into several variants of an algorithm for the extraction of Boolean rules. That algorithm has already been used in two real-world applications. Finally, a connection to the extraction of rules of the Łukasiewicz logic is established, relying on recent results about rational McNaughton functions. Based on one of the constructive proofs of the McNaughton theorem, an algorithm is formulated that in principle allows extracting a particular kind of formulas of the Łukasiewicz predicate logic from piecewise-linear neural networks trained with rational data.
Computation of Madalines' Sensitivity to Input and Weight Perturbations
Authors: Wang Yingfeng , Zeng Xiaoqin , Yeung Daniel So , Peng Zhihang
Published: September 2006

The sensitivity of a neural network's output to its input and weight perturbations is an important measure for evaluating the network's performance. In this letter, we propose an approach to quantify the sensitivity of Madalines. The sensitivity is defined as the probability of output deviation due to input and weight perturbations with respect to overall input patterns. Based on the structural characteristics of Madalines, a bottomup strategy is followed, along which the sensitivity of single neurons, that is, Adalines, is considered first and then the sensitivity of the entire Madaline network. Bymeans of probability theory, an analytical formula is derived for the calculation of Adalines' sensitivity, and an algorithm is designed for the computation of Madalines' sensitivity. Computer simulations are run to verify the effectiveness of the formula and algorithm. The simulation results are in good agreement with the theoretical results.
Nematicidal activity of medicinal plant extracts and two cinnamates isolated from Kaempferia galanga L. (Proh Hom) against the pine wood nematode, Bursaphelenchus xylophilus
Authors: Choi In-Ho , Park Ju-Yong , Shin Sang-Chul , Park Il-Kwon
Published: September 2006

Extracts from 40 medicinal plant species in 27 families were tested for their
nematicidal activity against the pine wood nematode, Bursaphelenchus
xylophilus, in 96-well plate bioassays. Responses varied with plant material
and concentration. Extracts of Acorus gramineus (Araceae), Asiasarum
sieboldi (Aristolochiaceae), Illicium verum (Illicaiceae) and Kaempferia
galanga (Zingiberaceae) showed nematicidal activity against male, female and
juvenile nematodes of B. xylophilus at 2000 μg ml−1. Among test plant
species, Kaempferia galanga showed the most potent nematicidal activity. As
K. galanga was the most nematicidally active of the 40 species, the extracts
were chromatographically fractionated and two cinnamates, ethyl
trans-cinnamate and ethyl p-methoxycinnamate, were discovered to be
responsible for much of the activity. The nematicidal activity of ethyl
trans-cinnamate and ethyl p-methoxycinnamate was 100% at 60 μg ml−1.
Panagrolobus vanmegenae, a new genus and species from The Netherlands and Ukraine, with taxonomic revision and two new species of the genus Teratolobus Andrássy, 1968 (Nematoda: Cephalobidae)
Authors: Holovachov Oleksandr , Boström Sven
Published: September 2006

Five species of the subfamily Acrolobinae, viz. Panagrolobus vanmegenae gen. n., sp. n., Teratolobus regulus Andrássy, 1968, T. obscurus sp. n., T. hamatus (Andrássy, 1986) comb. n. and T. similis sp. n., are described and illustrated from material collected in The Netherlands, Ukraine, Costa Rica, Mexico, Australia and South Africa. The new genus is characterised by a crown-shaped labial region with six well-developed, leaf-like lips having a biradial symmetry; lips separated by narrow and internally sclerotised U-shaped clefts; lateral lips half as wide as the subdorsal and subventral ones; a broad anisomorphic stoma; strongly sclerotised, hookshaped, cheilorhabdia; a strongly developed dorsal prostegorhabdion extending inside the stegostom cavity; a conoid tail with a rounded terminus bearing a dorsally curved, hook-like, mucro; and phasmids located at 70-90% of tail length. Teratolobus obscurus sp. n. is distinguished from the closely related T. regulus by the following characters: a smaller spermatheca (7.0-14.5 vs 26-61 μm); a shorter PUB (12-19 vs 18-42 μm); a shorter female tail (42-50 vs 55-72 μm); and differently shaped mucro on the tail terminus (harpoon-like vs hook-like). Teratolobus similis sp. n. is distinguished from the closely related T. baloghi (Andrássy, 1986) comb. n. by the following characters: a smaller body (350-420 vs 470-480 μm); a shorter PUB (9-12 vs 35-38 μm; 0.5-0.8 vs ca. 2 VBD long); shorter female tail (41-53 vs 62-65 μm; c′ = 3.4-5.4 vs 6.5-7.0); and differently shaped mucro on the tail terminus (arrowhead-like vs finely forked). Based on current research, a revision is proposed of the taxonomy of the genus Teratolobus and the subfamily Acrolobinae. The following new combinations are proposed: Teratolobus baloghi; T. hamatus; and T. occultus (De Ley & Coomans, 1990) comb. n. Panagroteratus is proposed as a synonym of Teratolobus.
Phylogenetic analysis of Tylenchida Thorne, 1949 as inferred from D2 and D3 expansion fragments of the 28S rRNA gene sequences
Authors: Subbotin Sergei A. , Sturhan Dieter , Chizhov Vladimir N. , Vovlas Nicola , Baldwin James G.
Published: September 2006

The evolutionary relationships of 82 species of tylenchid and aphelenchid
nematodes were evaluated by use of sequence data of the D2 and D3 expansion
fragments of the 28S ribosomal RNA genes. Nine automatic and one culled
sequence alignments were analysed using maximum parsimony and Bayesian
inference approaches. The molecular data sets showed that the order
Tylenchida comprises lineages that largely correspond to two suborders,
Hoplolaimina and Criconematina, and other taxonomic divisions as proposed by
Siddiqi (2000). Several significant results also derived from our study
include: i) the basal position of groups that include entomoparasitic
nematodes within tylenchid trees; ii) paraphyly of the superfamily
Dolichodoroidea sensu Siddiqi (2000); iii) evidence for a Pratylenchus,
Hirschmanniella and Meloidogyne clade; and iv) lack of support for widely
held traditional placement of Radopholus within Pratylenchidae and placement
of this genus within Hoplolaimidae or Heteroderidae. Congruence and
incongruence of molecular phylogeny and traditional classifications and
morphological-based hypotheses of phylogeny of tylenchids are discussed.
Molecular characterisation of two novel 17β-hydroxysteroid dehydrogenase genes from the soybean cyst nematode Heterodera glycines
Authors: Skantar Andrea M. , Guimond Nicole A. , Chitwood David J.
Published: September 2006

Heterodera glycines Hg-hsd-1 and Hg-hsd-2 are two homologues of let-767, a
short-chain dehydrogenase gene from the free-living nematode Caenorhabditis
elegans. Both genes share similarity to 17β-hydroxysteroid dehydrogenases
(17β-HSDs), enzymes known to be involved in the production of steroid
hormones in mammals. Hg-hsd-1 and Hg-hsd-2 encode distinct protein sequences
that share 51% amino acid identity with each other and 48% identity with
LET-767. The Hg-HSD-1 protein sequence was most similar to those encoded by
ESTs from the lesion nematode, Pratylenchus penetrans, and Hg-HSD-2 protein
was most similar to sequences from another cyst nematode, Globodera pallida.
Quantitative real-time PCR revealed the highest expression of both genes in
developing females, with relatively low levels in second-stage juveniles,
eggs, or males. Transcription levels of both genes declined as females aged,
decreasing with increased cuticle pigmentation. Transcription was
up-regulated in the cyst bodies and fluid that had been manually separated
from the developing embryos, suggesting that Hg-hsd-1 and Hg-hsd-2 are most
likely involved in gonad development or oogenesis in the female. It is
possible that these 17β-hydroxysteroid dehydrogenases are involved in the
conversion of sterols, which nematodes must ingest from dietary sources,
into necessary steroid hormones.
DESS: a versatile solution for preserving morphology and extractable DNA of nematodes
Authors: Yoder Melissa , De Ley Irma Tandingan , Wm King Ian , Mundo-Ocampo Manuel , Mann Jenna , Blaxter Mark , Poiras Larisa , De Ley Paul
Published: September 2006

A solution containing dimethyl sulphoxide, disodium EDTA, and saturated NaCl
(abbreviated here as DESS) was tested for various applications in the
preservation of nematodes for combined morphological and molecular analyses.
The solution can be used to preserve individual nematodes, nematode
extracts, or entire soil/sediment samples. Preserved material can be easily
stored for months at room temperature, shipped by mail, or carried in
luggage. Morphological features are usually well preserved; specimen quality
being comparable to formalin-based fixatives and much better than ethanol
fixation. Specimens can be transferred to glycerin with little or no
modification of traditional protocols. Unlike formalin-preserved material,
routine PCR can be performed on individual specimens after any of these
procedures with success rates and amplification sizes comparable to PCR of
fresh specimens. At this point we have no data on long-term preservation
quality. Nevertheless, DESS solution clearly enhances and simplifies a wide
range of nematological studies due to its combined suitability for
morphological and molecular analyses, as well as its less hazardous chemical
properties.
Laboratory studies on the enhancement of nematicidal activity of ammonia-releasing fertilisers by alkaline amendments
Authors: Oka Yuji , Tkachi Nadia , Shuker Shimshon , Rosenberg Rivka , Suriano Shoshi , Fine Pinchas
Published: September 2006

The effect of manipulating soil pH on the nematicidal activity of
ammonia-releasing fertilisers was tested with cement kiln dust (CKD) and
alkaline stabilised biosolid (ASB) as alkaline amendments. The nematicidal
activity of chicken litter (1.0, 2.0 and 4.0 g kg−1) or ammonium sulphate
(50 mg N kg−1) was enhanced by combination with CKD at 1.0 and 2.0 g kg−1 or
ASB at 5, 10 and 20 g kg−1. The amendment of soil with alkaline amendments
or fertilisers alone did not reduce, or reduced only moderately, Meloidogyne
javanica infection of the plant roots. The application of CKD and ASB
increased the soil pH from ca 8.5 to ca 11.0, and converted ammonium (NH+4)
released from the fertilisers into nematicidal ammonia (NH3). Increased
ammonia concentrations by 5.2- to 6.7-fold in the soil were probably the
major factor responsible for nematode suppression, whereas increased soil pH
was less detrimental to the nematodes. Combination of ammonia-releasing
fertilisers with alkaline amendments to soil may serve as a nematode control
method.
Chromosome structure and behaviour in Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae) germ cells and early embryo
Authors: Hasegawa Koichi , Mota Manuel M. , Futai Kazuyoshi , Miwa Johji
Published: September 2006

Chromosome structure and behaviour in both meiosis of the germ cells and mitosis of the embryo from fertilisation to the two-cell stage in Bursaphelenchus xylophilus were examined by DAPI staining and three-dimensional reconstruction of serial-section images from confocal laser-scanning microscopy. By this method, each chromosome's shape and behaviour were clearly visible in early embryogenesis from fertilisation through the formation and fusion of the male and female pronuclei to the first mitotic division. The male pronucleus was bigger than that of the female, although the oocyte is larger and richer in nutrients than the sperm. From the shape of the separating chromosomes at anaphase, the mitotic chromosomes appeared to be polycentric or holocentric rather than monocentric. Each chromosome was clearly distinguishable in the male and female germ cells, pronuclei of the one-cell stage embryo, and the early embryonic nuclei. The haploid number of chromosomes (N) was six (2n = 12), and all chromosomes appeared similar. The chromosome pair containing the ribosomal RNA-coding site was visualised by fluorescence in situ hybridisation. Unlike the sex determination system in Caenorhabditis elegans (XX in hermaphrodite and XO in male), the system for B. xylophilus may consist of an XX female and an XY male.
New Thelastomatoidea (Nematoda: Oxyurida) from Australian burrowing cockroaches (Blaberidae: Geoscapheinae, Panesthiinae)
Authors: Jex Aaron R. , Schneider Margaret A. , Rose Harley A. , Cribb Tom H.
Published: September 2006

Four new species and two new genera of thelastomatoid are described from several species of Australian burrowing cockroaches (Blattodea: Panesthiinae; Geoscapheinae). Corpicracens munozae n. g., n. sp., Pseudodesmicola botti n. g., n. sp. and Cephalobellus nolani n. sp. are described from Geoscapheus dilatatus (Blattodea: Geoscapheinae) from Mendooran, New South Wales; one new thelastomatid, Blattophila praelongicauda n. sp., is described from Panesthia cribrata from Lamington National Park, Queensland. Corpicracens munozae n. g., n. sp. is long and slender, with a monodelphic female reproductive system, a clavate corpus with a slight posterior pseudobulb, oval eggs flattened at the poles, and a relatively robust, subulate tail. Pseudodesmicola botti n. g., n. sp. is slightly more robust in body, also has a monodelphic reproductive system, a cylindrical corpus with a posterior pseudobulb, ovoid eggs and a very long, subulate tail. Cephalobellus nolani n. sp. is distinguished from other members of the genus by its relatively short and broad body and egg shape. Lastly, Blattophila praelongicauda n. sp. is distinguished from other members of the genus by having eggs with a single, polar operculum, tail length, and position of the vulva, nerve ring and excretory pore. An additional species, known by a single specimen from Panesthia tryoni tryoni from the same locality is characterised but not named. The species found are all relatively rare parasites of Australian burrowing cockroaches, each having a prevalence of less than 10%.
Thelastomatoidea (Nematoda: Oxyurida) of the Australian giant burrowing cockroach, Macropanesthia rhinoceros (Blaberidae: Geoscapheinae)
Authors: Jex Aaron R. , Schneider Margaret A. , Rose Harley A. , Cribb Thomas H.
Published: September 2006

The thelastomatoid fauna of Macropanesthia rhinoceros was examined from 13
localities across its range in Queensland, Australia. Nine species of
thelastomatoids, including two representing new genera, Geoscaphenema
megaovum n. g., n. sp. and Jaidenema rhinoceratum n. g., n. sp., were found.
Macropanesthia rhinoceros is reported as a new host for seven species
previously recorded from Panesthia cribrata (Blaberidae: Panesthiinae) and
P. tryoni tryoni, viz, Blattophila sphaerolaima, Leidynemella fusiformis,
Cordonicola gibsoni, Travassosinema jaidenae, Coronostoma australiae,
Hammerschmidtiella hochi and Desmicola ornata. Overall estimated richness
for the system ranged from 10.1-13.5 species. The high degree of parasite
faunal overlap between M. rhinoceros and the two Panesthia species is
surprising given the disparate ecological niches that they occupy; P.
cribrata and P. tryoni tryoni burrow in, and feed upon, moist decaying wood
and require a climate that is moist all year round, whereas M. rhinoceros
burrows in loose soil, feeds on fallen leaf litter and is tolerant of much
drier environments.
How different is induced host resistance against the pine wood nematode, Bursaphelenchus xylophilus, by two avirulent microbes?
Authors: Takeuchi Yuko , Kanzaki Natsumi , Futai Kazuyoshi
Published: September 2006

Pine wilt disease, caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, has been devastating pine forests in Japan for a century but an effective method for controlling the disease is still needed. Pre-inoculation of the host plant with an avirulent pathogen can induce resistance against subsequent infection with virulent pathogens; this is called 'induced resistance'. Host pine trees have this type of resistance against pine wilt disease but the detailed mechanism is unknown. In this study, 1-year-old potted seedlings of the susceptible Japanese black pine, Pinus thunbergii, were pre-inoculated with an avirulent isolate of PWN (C14-5), as well as an avirulent fungus, Botrytis cinerea, to induce host resistance against PWN. One, 2, 3, 4 and 5 weeks after inoculation, the seedlings were challenged with a virulent isolate of PWN (S10), and the survival of these seedlings was estimated by their external symptoms. Pre-inoculation with either C14-5 or Botrytis delayed the symptom development caused by subsequent inoculation with S10, suggesting that pre-inoculation induced host resistance against PWN. The resistance induced by pre-inoculation with C14-5 lasted for at least 5 weeks, while that induced by Botrytis weakened with time. It has been reported that the PWN survives inside the host seedlings for a long period without causing any symptoms under certain conditions, but Botrytis survives only for a while in the seedlings. Thus, the duration of host resistance induced by pre-inoculation may vary with the viability of the inoculum used for pre-inoculation. In order to obtain durable induced resistance, it may be necessary to repeat inoculations of avirulent microbes to be able to control pine wilt disease.
Special Section: Contemporary Challenges for Research in Group Analysis
Authors: Lorentzen Steinar
Published: September 2006

In this paper, I underline the challenges for group-analytic research by demonstrating the immense difference in the amount of research done in group psychotherapy in general as compared to group analysis. After presenting an overview of findings from empirical, quantitative outcome studies in group psychotherapy at large, I will discuss some trends in contemporary group psychotherapy research, and finally, I will give a rough sketch of group-analytic research. I will focus on quantitative research and I will see group analysis as a clinical enterprise - a theory, model, art and craft that has been developed and can be used to treat psychiatric disorders, and toameliorate psychological problems.
Special Section: Setting the World on Wheels: Some Clinical Challenges of Evidence-Based Practice
Authors: Mace Chris
Published: September 2006

This article critically examines the aims and methods of evidence-based practice (EBP) with particular reference to group psychotherapy. Six challenges posed by EBP for every psychotherapist are described.
Special Section: Between Subjects and Matrix: Transitivity and the ‘Use of Objects’ in Group Therapy
Authors: Navridis Klimis
Published: September 2006

In this paper the author draws attention to how the images and themes in therapeutic groups evolve from the articulation of the ‘associative chains’, and how these evolve at a particular, intermediate, metaphorical semantic level, which is more ‘real’ (‘associative chains’), because of the inter-subjective nature of this process. The construction of images and thematic objects and their ‘use’ by the group, in Winnicottian terms, comprises one of the most productive and creative functions of the group in group therapy.
Special Section: From Calorie-Counting to Relationships
Authors: Reilly Elizabeth A.
Published: September 2006

Beginning with the notion that eating disorders have become the typical ailment of our generation, the author discusses key developments within the contemporary multi-theoretical literature leading to an emerging focus on the role of inter-personal relationships within the psychopathology. Within this, attention is narrowed to a restricted obsessional and concretized repertoire of food which severely limits inter-personal functioning and the capacity for reflection on the same, producing a quasi-symbiotic picture. Following Foulkes’s ideas on open communication, the author details her work with this client group in a short-term group-analytic group and how this relates to multi-disciplinary work that itself derived principally from cognitive behavioural methodologies. The value of such short-term interventions is stressed with this client group, as is its place within the wider organizational context.
The Role of Narcissism in Group Psychotherapy
Authors: Battegay Raymond
Published: September 2006

This article analyzes five phases in the group process in which narcissism may, also on an archaic basis, be seen to be present, and its effect both on the individuals and the group process, as well as towards the conductor. The author also refers to the tasks of the therapist in respect of this narcissism, as it affects the individual, the other group members, and the group-as-a-whole.
Researcher and Therapist in the Same Person - a Feasible Combination? Review of Steinar Lorentzen’s Doctoral Thesis: ‘Long-term Analytic Group Psychotherapy with Outpatients: Evaluation of Process and Change’
Authors: Sandahl Christer , Wilberg Theresa
Published: September 2006

In this article, the authors discuss some of the dilemmas inherent in the combined role of being both clinician and researcher, and some central methodological problems connected to research on long-term psychotherapy. The thesis represents an important contribution to the field, which is in serious need of empirical research on long-term group-analytic psychotherapy. Lorentzen’s work has in an exemplary way demonstrated that it is possible to combine the roles of clinician and researcher.
The Archetypes Echoed in the Collective Unconscious of the People
Authors: Sandić Marijana , Sandić Aneta
Published: September 2006

The socio-cultural matrix of Bosnia-Herzegovina led towards victory of the nationalist parties in the multi-party elections in 1991. Carefully chosen party leaders, awakening the archaic images, led people into what Fromm called the ‘semi-hypnoid state of consciousness’. This caused the breakout of fratricidal - so-called civil - war, to the scene. It lasted from 6 April 1992 to 14 December1995. From then until the present time, Bosnia-Herzegovina has witnessed individuals emerging as political-economical ogres. Controlling the social order in Bosnia-Herzegovina, a part of former Socialist Federal Republic of Yugoslavia, they dictate the replacement of the socialistic regime in which we once lived, imposing the lifestyle codes of their narcissistic culture.
Dynamic Piezothermoelastic Responses of a Two-layered Composite Hollow Cylinder Constructed of Elastic and Pyroelectric Layers
Authors: Wang H. M. , Ding H. J.
Published: September 2006

Theoretical analysis is developed for an infinite composite hollow cylinder constructed of elastic and pyroelectric layers subjected to axisymmetric dynamic thermal loads. The solutions are based on piezothermoelastic theory. In terms of the charge equation of electrostatics, the radial electric displacement is first expressed as a product of a known function of radial coordinate and an unknown function of time. Then, the solution for the elastic field is obtained by the method of superposition. Finally, by means of the electric potential boundary conditions, a second kind of Volterra integral equation, which can be solved by the interpolation method, is derived to determine the unknown function of time. As a numerical experiment, the transient responses for the uniformly heated steel/CdSe composite hollow cylinder are illustrated graphically.
Estimation of Elastoplastic Thermal and Residual Stresses in a Thermoplastic Composite Disc Under Uniform Temperature Effect
Authors: Sen Faruk
Published: September 2006

In this study, an elastoplastic thermal stress analysis has been carried out on a thermoplastic composite disc that is unidirectionally reinforced by steel fibers. The finite element method (FEM) was used to compute thermal elastic and elastoplastic stress distributions in the model of the composite disc. The solution is performed using the ANSYS program. In order to evaluate the effects of uniform temperature, different temperature loadings are applied to the disc model uniformly. Both radial and tangential stresses are calculated under a uniform temperature loading which is chosen from between 80 to 120 C. Due to the composite disc having different thermal expansions in radial and tangential directions, thermal stresses were calculated by applying uniform temperature loading. The magnitude of tangential stress components for both elastic and elastoplastic solutions is higher than that of radial stress components. Moreover, residual stress components are obtained using the results of elastic and elastoplastic solutions. The calculated results point out that distributions and values of improved thermal stresses and residual stresses are considerably influenced with increasing uniform temperature loading.
Characterization of Composite Materials Based on PP-Cork Blends
Authors: Abdallah F. Ben , Cheikh R. Ben , Baklouti M. , Denchev Z. , Cunha A. M.
Published: September 2006

This article studies the possibility of making a cork fiber to reinforce plastics (polypropylene, PP). The thermal and structural properties of natural fibers are determined. The hydrophilic character of cork and the hydrophobic character of PP eliminate all chemical adhesion between the fiber and the matrix. This article gives a method of surface modification of cork which ameliorates the fiber-matrix adhesion (their results effects on the mechanical properties of composites). The method consists of hot water treatment. First, the influence of water treatment on the mechanical, thermal, and structural properties of the cork used to reinforce the composites is studied. This study is used to prepare a composite material with good mechanical and thermal properties without destruction of the cellular structure. The specimens of cork are treated with boiling water at ambient pressure for 1, 2 and 3 h and then washed with cold water. The specimens are dried in a dry oven at 70 C for 3 h. The results obtained show that density decreases as a function of water treatment time. This study also describes the influence of water treatment on the thermal behavior of the cork. An increase in thermal stability with water treatment time, in a nitrogen atmosphere, is noticed. In an isothermal study, a loss of mass of 5% after 30 min at 180 Cis observed. The specimens of treated and untreated cork are used to reinforce the PP matrix. The tensile test shows the importance of the surface modification of cork used in composites, particularly after treatment for 1 h. The adhesion properties of PP-cork are described with scanning electron microscopy (SEM).
Mechanical Buckling Behavior of Hybrid Laminated Composite Plates with Inclined Crack
Authors: Önal Gurol
Published: September 2006

Buckling analysis of symmetric and antisymmetric cross-ply laminated hybrid composite plates with an inclined crack subjected to a uniform compression is investigated in this article. The first-order shear deformation theory in conjunction with the variational energy method is employed in the mathematical formulation. The effects of crack size, crack inclination angle, and lay-up sequences on the buckling loads are investigated. The results are shown in graphical form for various conditions.
The Structure of O*NET Occupational Values
Authors: Smith Thomas J. , Campbell Cynthia
Published: September 2006

The structure of occupational values is investigated using several analytical techniques. Data from the U.S. Department of Labor’s Occupational Information Network (O*NET) describing need reinforcers for 900 occupations are examined using exploratory factor analysis, cluster analysis, and multidimensional scaling. Results indicated broadly defined values that primarily reflected elements of work-place identity and workplace structure.
Preparation and characterisation of nanostructured tin oxide (SnO2) films by sol–gel spin coating technique
Authors: Savarimuthu E. , Sankarasubramanian N. , Subramanian B. , Jayachandran M. , Sanjeeviraja C. , Ramamurthy S.
Published: September 2006

Highly transparent tin oxide thin films (SnO2) have been prepared using the sol–gel spin coating technique, optimising process parameters such as the solute concentration, spin rate and time of the turn table, film thickness (number of coatings) and heat treatment temperature. The X-ray diffraction (XRD) studies point to the polycrystalline structure of the developed films. The films deposited under optimum conditions are highly transparent in the visible region with a transmittance of 94% at 550 nm and have a resistivity of 3 × 10−2 Ωcm. The films have been obtained at a relatively low process temperature of 400°C.
Cyclic oxidation behaviour of rare earth oxide coated Fe–20Cr alloys
Authors: Fernandes S. M. C. , Ramanathan L. V.
Published: September 2006

The use of rare earths (REs) to increase high temperature oxidation resistance of chromium dioxide and alumina forming alloys is well known. The REs can be added as elements (or oxides) to the alloys or applied as an oxide coating to the alloy surface. The sol gel technique is very efficient to apply fine oxide particle coatings. The influence of various RE oxide gels such as La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Gd2O3, Dy2O3, Y2O3, Er2O3 and Yb2O3 on cyclic oxidation behaviour (RT-900°C) of Fe–20Cr alloy has been studied. The morphology and coverage of the RE oxide gels varied with the type of RE. The cyclic oxidation resistance increases with increase in time at temperature required to reach a specific chromium dioxide layer thickness and this is influenced by RE ion radius and characteristics of the RE oxide coating such as morphology, stability, coverage, resistance to thermal stresses and consequently adhesion.
Composition and microstructure of modified silicide coating on niobium
Authors: Yin L. , Yi D. , Yang L.
Published: September 2006

The high temperature oxidation resistance of a modified silicide coating on niobium was prepared by the slurry firing method. The cyclic antioxidation characteristics of the coating have been tested from room temperature to 1600°C. The microstructures and phase distribution of the coating have been characterised by SEM, EDX and XRD analyses, and the microhardness was measured on the cross-section of the coating. A typical multilayer structure was observed on the coating. The non-uniform distribution of the composition is likely due to the interdiffusion and reaction between the different layers. Crack propagation was observed during the cyclic high temperature oxidation test and was attributed to the thermal expansion mismatch.
Influence of shot peening on tension–tension fatigue property of two high strength Ti alloys
Authors: Gao Y.-K.
Published: September 2006

Surface roughness, residual compressive stress caused by shot peening and the effect of shot peening on fatigue property of Ti–5Al–5Mo–5V–1Cr–1Fe (TC18) and Ti–10V–2Fe–3Al (TB6) titanium alloys were investigated. The results show that fatigue limit for 1 × 107 cycles can be increased by 27 and 29% for TC18 and TB6 titanium alloys respectively. By comparing fatigue life under the same stress for different shot peening regimes treated specimens, the optimum shot peening process was determined. For a given material, there is an optimal shot peening intensity, and insufficient shot peening and over shot peening will not result in good fatigue performance. However, double shot peening, a shot peening process by which parts are peened initially with cast iron shot to induce a deep residual compressive stress field, followed by shot peening with glass shot to decrease the surface roughness and to remove the contaminants caused by the cast iron shot, can significantly improve fatigue performance.
Effect of cutting tools and cut materials on integrity of mirror surfaces
Authors: Prohászka J. , Horváth M. , Mamalis A. G. , Nyirö J.
Published: September 2006

The thermodynamic features of cutting tools and the cut materials change during cutting owing to their interactions and are considered in the present paper. The temperature of both increases, but, while the temperature and load on the cutting tool, during continuous cutting, may be considered as constant; the temperature of the machined material, in regions close to the cut surface, change both in time and space. When the crystal structure of the machined material is sensitive to changes in temperature, phase transitions, hardening or softening can occur in the surface layer. In particular the phase transition to a martensitic material involves hardening of a soft material. These transitions are of great importance, especially, in the case of ultra precision machining of mirror like surfaces. Similar changes of surface roughness are caused by the anisotropy of the modulus of elasticity. The component of Young's modulus, perpendicular to a cut surface, mainly depends on crystal orientation and therefore, elastic deformations change from individual crystallite to crystallite.
Fatigue behaviour of 7075-T6 aluminium alloy coated with WC–12Co alloy deposited by plasma spray
Authors: Puchi-Cabrera E. S. , Maccio R. , Staia M. H.
Published: September 2006

This investigation has studied the effect of a WC–12Co alloy deposited by plasma spray on the fatigue and corrosion fatigue properties of a 7075-T6 aluminium alloy, as part of its validation as a viable replacement of electrolytic hard chromium plating for aircraft applications. It has been determined that coating this substrate alloy with a deposit of ∼50 μm gives rise to a significant decrease in the fatigue and corrosion fatigue properties of the substrate coating system in comparison with the uncoated substrate. Thus, if the substrate coating system is tested in air at maximum alternating stress in the range 219–377 MPa, the fatigue life debit varies between 86 and 73% in comparison with the uncoated substrate. On the other hand, if the substrate coating system is tested in a 3%NaCl solution in the same range of alternating stress, the fatigue life debit varies between 23 and 73%. However, at alternating stresses <200 MPa the coated system behaves as the uncoated substrate. The results of the corrosion fatigue tests and the fractographic analysis conducted in some representative samples have shown that the corrosion fatigue process of the substrate coating system is controlled by the early nucleation of fatigue cracks on the surface of the WC–Co coating, owing to its highly heterogeneous microstructure, and their subsequent propagation within it and along the substrate/coating interface. In this way, once the NaCl solution is able to reach the interface, the fracture mechanism of the coated substrate occurs in a similar manner to that of the uncoated substrate. The evaluation of the static mechanical properties of both the uncoated and coated alloy has indicated that the yield and tensile stress of the substrate coating system decrease by about 27 and 8% respectively in relation to the uncoated substrate. Such results can be accounted for not only by fracture and delamination of the coating during the elastic deformation of the system, but also by a possible overheating of the substrate during deposition that modifies the T6 condition of the substrate alloy. Thus, the decrease in fatigue properties has been partially explained by these two effects as well as the propagation of fatigue cracks from the coating to the substrate.
Evaluation of electrochemical and surface characteristics of conversion coatings on ZM21 magnesium alloy
Authors: Natarajan S. , Ravikiran V.
Published: September 2006

Surface of a metal or material is important and suitable modification of the surface can provide enhanced properties for different applications. Magnesium is the lightest of all structural metals. Its low density (1·8 g cc−1 in alloy form) coupled with favourable casting properties, makes magnesium the material of choice for light weight components. But the metal is chemically highly reactive and prone to corrosion. Hence modification of the surface is important. The magnesium alloy under consideration is Mg–Zn–Mn, (ZM21) alloy system, and the composition is 2·03Zn–0·81Mn over which phosphate–permanganate, chromate conversion coatings were applied. The samples were subjected to surface roughness measurements, salt spray exposure tests, electrochemical potentiostatic polarisation studies in corrosive environment such as NaCl, NaOH, Na2SO4, NaHCO3 and NH4NO3. Microstructural examination, SEM analysis (for surface morphology), Fourier transform infrared (FTIR) spectral investigation (for determining the functional group) and X-ray diffraction (XRD) measurements (for identifying the compound) have also been employed for assessing the surface characteristics of this alloy. The results, in general, indicate that coatings provide enhanced corrosion resistance. Scanning electron microscopy of chromate conversion coating on ZM21 Mg alloy shows an intense transgranular crack on the coated film surrounded by a scattered distribution of spongy nature of film product. Scanning electron microscopy of phosphate conversion coating on ZM21 Mg alloy reveals a complete coverage showing a dense population and continuous network of film product. The formation of bonds among phosphorous, oxygen and hydrogen elements was shown by FTIR studies. X-ray diffraction analysis revealed the formation of compounds such as MgMnO3, Mg(OH)2, Mg2H, HPO4 in phosphate–permanganate conversion coated alloy, and compounds such as ZnCr2O4, Cr–O, CrO2, MnCrO3 in chromate conversion coating.
Microstructural characterisation of NiWCrBSiC alloy coating produced by HVOF thermal spraying
Authors: Gil L. , Staia M. H. , Guevara R. , Puchi-Cabrera E. S. , Lewis D. B.
Published: September 2006

Nickel based self-fluxing thermal sprayed alloys have been used in many applications to protect machinery parts against wear and corrosion. Although the mechanical and chemical properties of nickel based self-fluxing coatings are well known, the constituents of the microstructure have not been fully analysed. In the present work, the coatings were thermal sprayed on a 1020 steel substrate using a JP-5000 gun. Scanning electron microscopy and transmission electron microscopy techniques were employed for microstructural characterisation of the coatings, as complementary techniques to the X-ray diffraction studies already published by the authors. It has been determined that the as sprayed coatings are formed by a multiphase structure with an inhomogeneous distribution of soluble elements in an FCC γ Ni matrix. However, a well distributed network of hard phases in the matrix has been found and these were identified as: silicides (Ni2Si), borides (W2B, B4Si, CrB41, W5 (Si,B)3, Cr3B5) and carbides (M23C6 type carbides where metals are Cr, W, Si and Ni). Also, some other complex phases such as C0·17Fe0·81Si0·02 and Ni2·9Cr0·7Fe0·36 were found. In particular, the existence of the borides had not been reported in the literature before possibly owing to their small size, of ∼0·31 μm.
Cyclic high temperature oxidation of HFPD thermal sprayed CoNiCrAlY coatings under simulated gas turbine and furnace environments
Authors: Higuera Hidalgo V. , Belzunce Varela F. J. , Riba López J.
Published: September 2006

CoNiCrAlY powders were thermal sprayed using the high frequency pulse detonation (HFPD) method onto AISI 310 austenitic stainless steel samples. The cyclic oxidation behaviour of these coatings at 800 and 1000°C in simulated gas turbine and standard atmosphere environments was experimentally determined. Austenitic AISI 310 was used as a reference. Composition and morphology of surface phase were evaluated using X-ray diffraction and scanning electron microscope techniques. Oxidised HFPD CoNiCrAlY coatings have always been characterised by the formation of a continuous and highly protective alumina layer. In contrast, the protection of the chromium oxide layer generated on the austenitic AISI 310 under the same operating conditions is much less effective and a degraded region near to the oxidised layer has been observed at the highest temperatures. Moreover, cracks appear in the chromium oxide layer when it is submitted to high thermal gradients, as a consequence of thermal stresses.
Process limitations of magnetically enhanced reactive ion etch equipment
Authors: Kim B. , Park J. Y. , Hong S. J.
Published: September 2006

In magnetically enhanced reactive ion etching (MERIE), it is conventionally understood that the etch rate increases with increasing magnetic field strength (MFS) owing to the increase in plasma density. However, it is uncertain that this can be valid under various plasma conditions. This concern was investigated by applying a statistical experimental design to an etching of aluminium thin films in a chlorine (Cl2) plasma. It was noticeable that five experimental cases were contradictory to the reported MFS effect. The major contributor was estimated to be the dominant effect of ion bombardment. The sensitivity analysis of three significant cases revealed a little interaction between MFS and Cl2 flow. Demonstrated high sensitivity of each contradictory case reveals that the process limitations of MERIE can be circumvented by controlling the process parameters.
Improvement in galling performance through surface engineering
Authors: Podgornik B. , Vižintin J. , Hogmark S.
Published: September 2006

The aim of the present work was to investigate and compare different surface engineering techniques in terms of galling properties of forming tool steel when sliding against different work materials. The surface engineering techniques included were different grades of polishing, plasma nitriding and different hard coatings, all applied to cold work tool steel respectively.

Investigation results indicate that the galling tendency can be greatly reduced by proper polishing of the tool surface. If polished after treatment, plasma nitrided surface will provide further improvement in friction and wear properties of the tool steel and especially for aluminium and titanium alloys reduce the galling tendency. On the other hand, coating selection for improved galling performance of coated forming tool steel greatly depends on the type of work material. In the case of stainless steel, carbon based coatings provide the best protection against the work material transfer, while forming of aluminium and titanium based alloys, requires nitride type coatings.
Mechanical properties of tool steels with diffusion carbon and nitrocarbon layers
Authors: Babul T. , Kucharieva N. , Nakonieczny A. , Senatorski J.
Published: September 2006

The present paper presents the results of metallographical investigation and wear tests of tool steel grades: hot work steels 4H5W2FS, AMS 6437E and cold work steels ASTM A681, Ch12FS. All surfaces were hardened by the Carbo process (carburising) and by the NiCar process (nitrocarburising). The thermochemical treatment was conducted in powder pack for durations of 6 h (carburising) and of 4 h in the case of nitrocarburising. Wear tests were conducted by the three cylinder cone method. Wear velocity was 0·58 m s−1, unit loads were 50 and 400 MPa, wear path was 3470 m. Oil SAE30 was applied at the rate of 30 drops/min−1. Factors investigated were: morphology, depth and microhardness of the cases obtained, their microstructure, as well as phase composition.
Evaluation of corrosion behaviour of organic coatings with electrochemical noise and electrochemical impedance spectroscopy
Authors: Mahjani M. G. , Neshati J. , Masiha H. P. , Ghanbarzadeh A. , Jafarian M.
Published: September 2006

Electrochemical noise (EN) and electrochemical impedance spectroscopy (EIS) measurements were used to evaluate protective properties and corrosion behaviour of two different organic coating systems. The coatings of commercial grade (zinc rich ethyl silicate) were applied to steel substrates and immersed for up to 3 months in 0·5M NaCl at 25°C. An analysis of the EN data was performed during this time, including the measurements of the mean potential Emean, the mean current Imean and the noise resistance Rn. The time series noise patterns were transformed into frequency domain by fast Fourier transformation. The power spectral densities (PSDs) of the potential and of the current and roll off slope coatings were then compared with each other. These coated plates were assessed by EIS. Electrolytic penetration through the coating, changes in the dynamic characteristics of the conduction and resistance of the coating film of the protected system as a function of time. Equivalent circuits were used to interpret the physical and electrochemical properties. The mechanism and kinetics of the electrochemical systems were assessed by measuring the fluctuations in capacitance and percentage of water uptake. The coatings were evaluated in salt spray and humidity tests according to ASTM B117 and D2247.
Humidity effect on friction and wear behaviour of self-lubricant coatings
Authors: Picas J. A. , Forn A. , Baile M. , Martín E.
Published: September 2006

A MoS2/titanium coating has been developed in order to improve the mechanical and tribological characteristics of pure MoS2. These coatings were produced by physical vapour deposition closed field unbalanced magnetron sputtering on stainless steel substrates. In this work, a comparative study of the mechanical and tribological characteristics of both coatings is carried out. The coating hardness and Young's modulus have been determined by means of an ultramicroindenter. The friction and wear tests have been carried out with a pin on disc tribometer in several conditions of load and humidity. The MoS2/titanium coating exhibited a better mechanical and tribological behaviour in comparison with pure MoS2 coating on increasing the percentage of humidity.
Comparison of integrated micro-electrical-mechanical system and piezoelectric accelerometers for machine condition monitoring
Authors: Thanagasundram S , Schlindwein F S
Published: September 2006

The design and implementation of instrumentation to collect real-time vibrational data from a quasi-steady state machine (a dry vacuum pump) for fault prediction diagnostics is presented. When simultaneous multiple data collection points are required on the same machinery, the use of conventional transducers such as piezoelectric accelerometers becomes impractical due to their price, as each needs an expensive associated charge amplifier. The use of inexpensive micromachined integrated micro-electrical-mechanical system accelerometers such as ADXL105 has been explored here as an alternative to piezoelectric accelerometers for obtaining reliable and predictable data for diagnostics. Surface micromachined accelerometers are a new technology and their usage for vibrational analysis has been conservative due to concerns over increased noise levels and tolerance to high temperatures. In this article, it is shown that such concerns can be allayed. The time and frequency domain vibration signatures obtained using both types of accelerometers are compared. The study shows that ADXL105 accelerometers can be an effective alternative low-cost high-quality solution for machine condition monitoring.