bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis and design of adhesively modified double-containment corner joints part 1
Authors: Davies R , Apalak M K , Apalak Z G
Published: July 2007

In this study, the stress and stiffness analyses of modified double-containment corner joints, in which plates are bonded at a right angle into slots of a corner support, were carried out using the finite element method. It was assumed that the adhesive and plates had linear-elastic properties. The presence of adhesive fillet at the adhesive free ends was taken into account. The corner joint was analysed for three loading conditions, two linear and one bending moment. It was found that the loading in the y direction is the most critical loading condition and that maximum stress concentrations occurred around the adhesive free ends. A detailed study of adhesive stresses showed that the peak adhesive stresses occurred at the lower free end of the left vertical adhesive layer-slot interface for the loading conditions Py and Mb respectively and the lower free end of the right vertical adhesive layer-slot interface for the loading condition Px. In addition, the effects of horizontal and vertical support lengths, slot depth and support thickness on the peak adhesive stresses and the overall joint stiffness were investigated. Dimensions of the corner support were given relative to the plate thickness.
An improved method for determining contact stresses
Authors: Soh A-K , Soh C-K
Published: July 2007

The conventional finite element method has been modified to allow the elastic stresses at the contact surface between two objects to be determined with improved accuracy. Both the problems of frictionless and frictional contacts were studied, and the results obtained by this modified method are compared with both a theoretical and a traditional finite element solution. The comparison shows that the modified solution is in better agreement with the theoretical solution as compared with the traditional solution.
Development and experimental validation of the deep hole method for residual stress measurement
Authors: Leggatt R H , Smith D J , Smith S D , Faure F
Published: July 2007

The development of a deep hole method, based on earlier techniques, for measuring the through-thickness distribution of residual stresses is described. The distortion of a reference hole used in the method was interpreted using analytical techniques to determine the residual stresses present. The accuracy of the method was investigated using a 100 mm deep plastically deformed ferritic steel rectangular bar. The stresses in the bar were determined by surface strain gauges. The axial residual stresses through the depth of the bar, measured by the deep hole method, were found to be within ± 35 MPa of the stresses determined from the strain gauges in the central 80 mm of the bar.
The solution of cracks emanating from circular holes
Authors: Lin S , Hills D A , Nowell D
Published: July 2007

A method for finding crack tip stress intensity factors for cracks emanating from circular holes, and subject to arbitrary remote loading, is described. Cases of single and multiple cracks are treated, using the distributed dislocation approach.
Some physiological observations on ketamine hydrochloride anaesthesia in the agamid lizard
Authors: Ogunranti J. O.
Published: July 2007

Some physiological parameters of the agamid lizard ( Agama agama agama) were studied after intramuscular injection of ketamine hydrochloride with or without diazepam. Heart rates and electrocardiograms were recorded. Respiratory rates were also monitored before and during anaesthesia. The study showed that ketamine given at a dose of 20-30 mg/kg body weight intramuscularly provides optimal anaesthesia for surgical procedures on the agamid lizard.
Record-keeping requirements of the Animals (Scientific Procedures) Act 1986 and how to meet them
Authors: Wootton R. , Flecknell P. A.
Published: July 2007

The new Animals (Scientific Procedures) Act 1986 has significant implications in terms of record keeping. In many designated establishments, however, most of the records are already collected as part of good working practice and the new Act merely formalizes this situation. Recording the required information may be tedious, but it can be carried out using either a paper-based system or its computerized equivalent. The new legislation imposes no additional record-keeping requirements on personal licence holders and the real burden falls on the project licence holder, particularly for large projects involving several personal licence holders. In the case of an animal house operating a computerized system, considerable assistance with project record keeping can be given by the designated establishment and project status reports will be very helpful in this respect. Computerization also enables automatic production of cage labels which ensures uniformity of labelling and compliance with the Home Office guidelines.
Isolation of Acholeplasmatales from rabbit faeces
Authors: Angulo A. F. , Doeksen M. , Hill A. , Polak-Vogelzang A. J.
Published: July 2007

Acholeplasma laidlawii was isolated from the faeces of 23·5% and 24% of groups of 51 conventional and 45 specified-pathogen-free (SPF) rabbits respectively. Isolation of the organism from individual animals could often be repeated, suggesting that infection was not merely transient. Two further acholeplasmas were isolated from two SPF rabbits. One was serologically related to Acholeplasma modicum. The other could not be identified and may be a new species.
Qualitative research on breastfeeding in the UK: a narrative review and methodological reflection
Authors: Miller Tina , Bonas Sheila , Dixon-Woods Mary
Published: July 2007

English

Levels of breastfeeding in the UK remain low compared with other European countries. Qualitative research is a potential source of important data on women’s infant feeding decisions and practices, but is currently omitted from systematic reviews in the area. We report a narrative review of qualitative studies of breastfeeding in the UK, and identify two main themes around which the literature can be organised: first, women’s experiences of infant feeding and feeding decisions; second, healthcare practices and support for breastfeeding. We also reflect on the methodological issues in conducting a review of this type.
‘What to do about political context?’ Evidence synthesis, the New Deal for Communities and the possibilities for evidence-based policy
Authors: Wright John S.F. , Parry Jayne , Mathers Jonathan
Published: July 2007

English

If policy is the sum of interactions between agents and organisations about an appropriate course of action, then political context refers to the structural, organisational and ideological aspects of the environment relevant to those interactions. Crucially, political context may modify how ‘evidence’ is used by policy makers. In this article, we use a case study – the New Deal for Communities regeneration programme – to explore further the influence of political context on the use of evidence by policy makers. We conclude that over time, the political landscape within which the initiative is implemented becomes increasingly important in determining the use of evidence.
Immunolocalization of Sibling and RUNX2 Proteins During Vertical Distraction Osteogenesis in the Human Mandible
Authors: Amir Lisa R. , Jovanovic Andreas , Perdijk Frits B. T. , Toyosawa Satoru , Everts Vincent , Bronckers Antonius L. J. J.
Published: July 2007

We tested the hypothesis that mechanical loading of human bone increases expression of the transcription factor RUNX2 and bone matrix proteins osteopontin (OPN), bone sialoprotein (BSP), dentin matrix protein-1 (DMP1), and matrix extracellular phosphoglycoprotein (MEPE). We examined this in tissue sections of atrophic mandibular bone taken from edentulous patients who had undergone distraction osteogenesis. In undistracted bone, weak to moderate staining for OPN and BSP was found in osteoblasts and bone matrix of immature woven bone. RUNX2 was also detectable in osteoblasts and in cells of the periosteum. In woven bone, but not in lamellar bone, a small number of osteocytes stained for all proteins tested. After distraction, staining intensity had increased in the existing old bone and staining was seen in more bone cells than before distraction. We also found a high expression of DMP1 and MEPE in many osteocytes embedded in woven bone and in some osteocytes of lamellar bone not seen before distraction. New bone trabeculae were forming in the fibrous tissue of the distraction gap containing all stages of intramembranous bone formation. Moderate to strong staining was seen for all five proteins tested in osteocytes located in woven bone of these trabeculae and for RUNX2, OPN, and BSP in osteoblasts lining the trabecular surfaces. We conclude that loading of atrophic human jawbone by distraction activates matrix synthesis of bone cells in and around existing bone. Increased staining of DMP1 and MEPE in osteocytes after loading is in line with the concept that these proteins may be involved in signaling the effector cells to adapt the bone structure to its mechanical demands.
Mitochondrial Ferritin Expression in Adult Mouse Tissues
Authors: Santambrogio Paolo , Biasiotto Giorgio , Sanvito Francesca , Olivieri Stefano , Arosio Paolo , Levi Sonia
Published: July 2007

Mitochondrial ferritin (FtMt) is a novel ferritin type specifically targeted to mitochondria. It is highly expressed in the human testis and in sideroblasts from patients with sideroblastic anemia, but other organs have not been studied. To study its expression in the main organs of the mouse, we first used RT-PCR and then produced recombinant mouse FtMt and specific antibodies. Immunohistochemistry analyses confirmed that FtMt is highly expressed in mouse testis, particularly in spermatocytes and interstitial Leydig cells. The protein was also identified in other organs including heart, brain, spinal cord, kidney, and pancreatic islet of Langerhans but not in liver and splenocytes, which have iron storage function and express high levels of cytosolic ferritins. Results indicate that the primary function of ferritin FtMt is not involved in storing cellular or body iron, but its association with cell types characterized by high metabolic activity and oxygen consumption suggests a role in protecting mitochondria from iron-dependent oxidative damage.
Herbivory by tuco-tucos (Ctenomys mendocinus) on shrubs in the upper limit of the Monte desert (Argentina)
Authors: Tort Jorge , Campos Claudia M. , Borghi Carlos E.
Published: July 2007

Ctenomys(tuco-tuco) is a small fossorial herbivorous rodent of the Monte desert, and is probably the most abundant and widely distributed rodent in these arid lands. The aim of this study is to describe the impact ofC. mendocinusherbivory on shrubs in two plant communities (Reserve of Divisadero Largo and Villavicencio) in the upper limit of the Monte desert, and to assess the association between environmental variables and level of damage caused by tuco-tucos. Herbivory by tuco-tucos affected 39% of the total shrubs in Villavicencio, and 9.37% of the total plants sampled in Divisadero Largo. In Villavicencio, the most highly damaged species wereLarrea divaricata(65%),Lycium aff. chilensis(41%),Junellia seriphioides(38%) andMenodora decemfida(33%). In Divisadero Largo, damage was lower:J. seriphioides(14%),Lycium chilensis(9%), andM. decemfida(6%). With respect to the association between level of damage caused by tuco-tucos and environmental variables, in Divisadero Largo the level of damage was negatively associated with both maximum and mean soil depth, while in Villavicencio it was negatively associated with plant cover, and positively associated with maximum and mean soil depth. There was no association between level of damage caused by tuco-tucos and mean stone diameter.
Measuring Drained Residual Strengths in the Bromhead Ring Shear
Authors: Meehan Christopher L. , Brandon Thomas L. , Duncan J. Michael
Published: July 2007

A series of Bromhead ring shear tests were conducted to measure the drained residual strength of Rancho Solano Fat Clay. Tests conducted using different test procedures demonstrate the significant effect that wall friction can have in the Bromhead ring shear device. This problem was addressed by beveling the top loading platen, which led to measurements of drained residual strength that were 21–23 % lower than those measured with the unmodified platen. Using the modified platen, similar test results can be achieved independent of the details of the test procedure that is followed, giving greater confidence in the measured residual shear strength.
Seasonal Photosynthesis and Partitioning of Nonstructural Carbohydrates in Leafy Spurge (Euphorbia esula)
Authors: Gesch Russ W. , Palmquist Debra , Anderson James V.
Published: July 2007

Previous evidence indicates that changes in well-defined phases of dormancy in underground adventitious buds of leafy spurge in late summer and autumn are regulated by complex sensing and signaling pathways involving aboveground sugar signals. However, little information exists concerning seasonal photosynthesis and carbohydrate partitioning of leafy spurge, although such information would help to elucidate the involvement of sugar in controlling bud dormancy. An outdoor study was conducted over two growing seasons to determine and model seasonal patterns of photosynthesis and aboveground carbohydrate partitioning and their relationship to underground adventitious bud carbohydrate status. Photosynthesis and total nonstructural carbohydrate (TNC) content of aboveground tissues was greatest during vegetative growth. Photosynthesis gradually declined over the growing season, whereas TNC decreased sharply during flowering, followed by a gradual decline between midsummer and autumn. Leaf starch increased dramatically to midsummer before declining sharply throughout late summer and early autumn, whereas sucrose content responded inversely, indicating a mobilization of starch reserves and export of sugars to overwintering belowground sink tissues. Because newly formed underground adventitious buds showed a continuous increase in TNC from midsummer through autumn, export of sugars from aboveground tissues likely contributed to the increase in TNC. These results may facilitate new strategies for biological control of leafy spurge.
Treatment of Specific Phobias With EMDR: Conceptualization and Strategies for the Selection of Appropriate Memories
Authors: De Jongh Ad , ten Broeke Erik
Published: July 2007

Eye movement desensitization and reprocessing (EMDR) has been shown to be a structured, noninvasive, time-limited, and evidence-based treatment for unprocessed memories and related conditions. This paper focuses on EMDR as a treatment for specific fears and phobias. For this purpose, the application of EMDR is conceptualized as the selection and the subsequent processing of a series of strategically important memories of earlier negative learning experiences concerning specific objects or situations. Firstly, the practical application and conceptualization of the treatment of phobias with EMDR is presented and compared with an exposure-based treatment approach. Next, specific attention is given to the assessment and selection of appropriate memories for processing. It is hypothesized that phobias with a non-traumatic background, or those in later stages of treatment after some reduction in anxiety has been achieved, would profit more from the application of a gradual in vivo exposure, whereas trauma-based specific phobias and those with high initial levels of anxiety would respond most favorably to EMDR.
The Quest for High‐Performance Host Materials for Electrophosphorescent Blue Dopants
Authors: Wu M.‐F. , Yeh S.‐J. , Chen C.‐T. , Murayama H. , Tsuboi T. , Li W.‐S. , Chao I. , Liu S.‐W. , Wang J.‐K.
Published: July 2007

We report a systematic comparison study of 3,5‐di(N‐carbazolyl)tetraphenylsilane (SimCP) and N,N′‐dicarbazolyl‐3,5‐benzene (mCP), which are used as the host materials for phosphorescent blue dopants in organic light‐emitting diodes (OLEDs). On the basis of photoexcitation emission spectroscopy, thermal stability analysis, photoelectron analysis, charge transport measurements, and molecular dynamics (MD) simulations, we conclude that the non‐π‐conjugated meta‐substituted triphenylsilyl moiety of SimCP exerts a unique hindering effect on the molecular packing characteristics in the condensed phase. The chemical origin of the superior performance of SimCP over mCP is revealed, and is expected to be helpful for the molecular design of effective host materials for enhancing the performance of blue phosphorescent OLEDs.
Template‐Free Fabrication and Enhanced Photocatalytic Activity of Hierarchical Macro‐/Mesoporous Titania
Authors: Yu J. G. , Su Y. R. , Cheng B.
Published: July 2007

Hierarchical macro‐/mesoporous titania is prepared without the addition of templates or auxiliary additives at room temperature by the simple dropwise addition of tetrabutyl titanate to pure water, and then calcined at various temperatures. The products are characterized by X‐ray diffraction, N2‐adsorption–desorption analysis, scanning electron microscopy, and the corresponding photocatalytic activity is evaluated by measuring the photocatalytic oxidation of acetone in air. The results reveal that hierarchical macro‐/mesoporous structures of titania can spontaneously form by self‐assembly in alkoxide–water solutions in the absence of organic templates or auxiliary additives. The calcination temperature has a strong effect on the structures and photocatalytic activity of the prepared titania. At 300 °C, the calcined sample shows the highest photocatalytic activity. At 400 and 500 °C, the photocatalytic activity slightly decreases. When the calcination temperature is higher than 500 °C, the photocatalytic activity greatly decreases because of the destruction of the hierarchical macro‐/mesoporous structure of the titania and the drastic decrease of specific surface area. The hierarchically macro‐/mesostructured titania network with open and accessible pores is well‐preserved after calcination at 500 °C, indicating especially high thermal stability. The macroporous channel structures are even preserved after calcination at 800 °C. This hierarchical macro‐/mesostructured titania is significant because of its potential applications in photocatalysis, catalysis, solar‐cell, separation, and purification processes.
Layered Titanate Nanosheets Intercalated with Myoglobin for Direct Electrochemistry
Authors: Zhang L. , Zhang Q. , Li J.
Published: July 2007

The application of nanolayered inorganic materials as supports for immobilizing biomolecules has attracted attention because the host structures not only have “flexible pores” to adapt to the size of the biomolecule guests but they also protect the immobilized biomolecules from disturbances created by environmental variations. In this paper, layered titanate sheets (TNSs) were used as support matrixes for immobilizing myoglobin (Mb) to fabricate protein electrodes suitable for studying the direct electron transfer between the redox centers of proteins and the electrode and establish an example of a mediator‐free (third‐generation) biosensor. The uniform, porous morphology and ordered structure of the protein electrode were characterized by scanning electron microscopy, high‐resolution transmission electron microscopy, and X‐ray diffraction. The native structure of the intercalated Mb was maintained in the TNSs, and its behavior was characterized by UV‐vis and Fourier‐transform IR spectroscopy. Immobilized Mb in TNS films showed a fast direct electron transfer for the Mb–FeIII/FeII redox couple. Based on the direct electron transfer of the immobilized Mb, the protein electrode exhibited excellent catalytic performance for H2O2. Furthermore, in order to improve the stability of immobilized Mb in the TNS films, the thermal stability of the protein electrode and its electrochemical catalytic reduction of H2O2 in a low pH environment were discussed.
Reduktionswirkung der Zuckerarten und Zuckerzerfall
Authors: Fischler F. , Täufel K. , Souci S. W.
Published: July 2007

An Hand einer Zusammenstellung der zum Nachweis und zur quantitativen Bestimmung reduzierender Zuckerarten gebräuchlichen Reagenzien sowie auf der Grundlage eigener Untersuchungen wird der Schluß gezogen, daß die reduzierenden Eigenschaften der Zuckerarten in alkalischer Lösung nicht der ungespaltenen Molekel zukommen, sondern daß primär eine Aufspaltung der Hexosemoleküle unter Einfluß von Hydroxylionen in 3‐Kohlenstoffketten erfolgt, die ihrerseits Träger der Reduktionswirkung sind. Diese Schlußfolgerungen machen den nichtstöchiometrischen Verlauf der Reduktion im alkalischen Medium verständlich. Sie stehen andererseits in Übereinstimmung mit dem biologischen Verhalten des Traubenzuckers.
Über die Herstellung von Xylenolen und Äthylphenolen aus technischem Abfallxylidin bzw. Benzol
Authors: Brückner Horst
Published: July 2007

Trennung eines technischen Xylidingemisches. Darstellung der Xylenole aus den entsprechenden Xylidinen. Synthese von Äthylbenzol aus Benzol und Äthylen. Darstellung der Äthylphenole.
Die neue Theorie Einsteins über die Verschmelzung von Gravitation und Elektrizität
Authors: Reichenbach Hans
Published: July 2007

Inhalt: Die neue Theorie Einsteins geht auf die Weyl‐Eddingtonsche Verallgemeinerung des Riemannschen Raumes zurück, welche in ihren geometrischen Grundzügen geschildert wird. Durch die Zusammenfassung von Gravitation und Elektrizität in ein einheitliches Feld wird eine physikalische Verkettung beider behauptet, die in ihren Folgen und ihrer Wirklichkeitsgeltung jedoch noch nicht zu übersehen ist.
Fortschritte in der Photographie in den letzten 10 Jahren
Authors: Eggert J. , Mediger H.
Published: July 2007

Inhalt: Herstellung von Silbersalzemulsionen. — Optische Sensibilisierung. — Prüfungs‐ und Analysenmethoden. — Sensitometrie und Messungen an photographischen Schichten. — Prüfung von Blitzlichtmaterialien. — Lichtempfindliche Schichten ohne Silbersalze. — Trocknen photographischer Schichten. — Photographische Schichtträger.
Zerlegung der Koksofengase und Ausnützung ihrer Einzelbestandteile
Authors: Bronn J.
Published: July 2007

Inhalt : Änderung der Zusammensetzung der Koksofengase mit fortschreitender Gärung; durchschnittliche Zusammensetzung der Koksofengase und das Verhalten der Einzelbestandteile bei tiefen Temperaturen. Starke Streuung der Verflüssigungstemperaturen, hingegen sehr tiefe Erstarrungstemperaturen der einzelnen Gasarten; die mit der Linde schen Apparatur bis jetzt erreichten Ergebnisse in der Gewinnung der Einzelbestandteile. Bestrebungen, neben dem Wasserstoff (für die Ammoniaksynthese, Hydrierung, Fetthärtung) auch Äthylen und Methan ihren spezifischen Eigenschaften gemäß zu verwenden. (Polymerisation zu Ölen, Crackung; Verwendung als Triebstoff).
Physikalische Prüfungen an Pigmenten
Authors: Schmid F.
Published: July 2007

Im Anschluß an die Erörterungen der wissenschaftlichen Grundlagen für die Bestimmung der Helligkeit, des Deckvermögens und des Färbevermögens werden Verbesserungen an den bisherigen Methoden bzw. neue Verfahren zur Bestimmung dieser drei wichtigen farbtechnischen Kennzahlen beschrieben.
A simple bandwidth management scheme for multiservice ATM networks
Authors: Bianchi Giuseppe , Trecordi Vittorio
Published: July 2007

In this paper we outline a simple strategy to manage bandwidth allocation and congestion control and to guarantee service requirements in a multiservice ATM (asynchronous transfer mode) network. We propose a network architecture based on a core network, making available a limited number of quality of service profiles, and an access network, made of edge adapters in charge to match the user's requirements with the network's available quality of service profiles and to shape input traffic to achieve high network throughput. The connection admission rule is presented, and edge adapter architecture and design examples are given. The effectiveness of the scheme is demonstrated by numerical results which report the network utilization performance when the proposed core network policies and edge adapter design apply.
Temporal placement control of video frames in ATM networks
Authors: Lee Duan‐Shin , Sengupta Bhaskar
Published: July 2007

In this paper, we propose a new method of traffic smoothing for frames of different video sources. We assume that each video source transmits frames at fixed intervals and that the network is free to decide the relative temporal spacing of video frames from different sources. This means that the time at which a given source begins to transmit its first frame is under the control of the network; however, after that, all frames from this source are transmitted at fixed intervals. We now address two questions. What are some reasonable policies for spacing the frames of video sources? What is the performance advantage of doing this? We propose three control policies (two heuristic and one based on an optimization problem via some Fourier analysis). These are compared against the case in which the video frames from different sources are randomly distributed (i.e. no control is exercised). We show that significant performance advantages accrue if one controls the temporal placement of the video frames from different sources.
Performance evaluation of integrated services interworking: The ATM‐DQDB case
Authors: Venieris I. S. , Tsiotsios E. N. , Angelopoulos J. D.
Published: July 2007

Performance studies on LAN/MAN‐BISDN interworking have mainly focused on the requirements of isochronous and connectionless services. In this paper we extend performance results to cover also the case of non‐isochronous connection oriented (CO) services supported by the queued arbitrated (QA) mode of access of the DQDB protocol. Using this case we stress the more general issue of service integration impact on the interworking unit (IWU) architecture design in terms of protocol stacks and expected performance. We herein evaluate the performance of IWU architectures tailored to relay information in the lowest possible layer while implementing several service priority schemes and buffer management policies towards QoS objectives. The conditions under which the IWU design is efficient regarding performance, protocol complexity and implementation cost in this integrated services environment are identified.
Optimal channel assignment in cellular networks
Authors: Rouskas Angelos N. , Kazantzakis Michael G. , Anagnostou Miltiades E.
Published: July 2007

In this paper, we consider the problem of assigning frequencies to mobile terminals in a cellular network. We show that an optimal solution can be obtained by solving a sequence of alternating linear and quadratic maximization programming problems. We address co‐channel constraints and adopt as an objective function the maximization of potentially established calls. Our algorithm is fairly general, and does not depend on any special network structure. This study indicates that mathematical programming can be used as an efficient technique for solving the aforementioned problem.
Intersection functions of shortest paths in a nondirected graph
Authors: Kishi Genya , Sasakis Isao
Published: July 2007

An essential means to upgrade network reliability is to prepare several substitutable paths between two vertices. We idealize the substitutability in a narrow sense. We will study the mutual relationship between a bundle of shortest paths between any two vertices, and a third vertex from the viewpoint of path multiplicity in case there are some shortest paths between any two vertices. Initially, we will extend a concept of the cutting number, which represents a mutual relationship between a path of any pair of vertices and a third vertex in a tree graph. Then we will generalize it as the intersection function in any graph. Afterward, we will introduce conditions of decreasing this intersection function by inserting edges into the graph. Further, we will demonstrate the main features of this intersection function based upon the conditions. They can provide a new definition of the center in graphs with regard to reliability. We will extend the concept of the intersection function to an edge intersection function.
Evaluation of dynamic steps of path hunting in space‐division multistage switching networks
Authors: Ogino Nagao , Saito Tadao , Inose Hiroshi
Published: July 2007

Space‐division electronic switching systems require the use of a swtiching network with the fewest possible crosspoints, since switching elements are expensive. Therefore, the switching capacity must be limited to the extent that a switching network should be structured in a multistaged manner if the switching network itself must be large. However, switching networks with multistaged provisions generally need complex control. Accordingly, complex studies must be devoted to the amount of control, as well as to the switching efficiency, of networks in designing multistaged switching networks. These considerations herein lead to an evaluation study on the amount of control for path hunting and clarification of the relationship between switching network types and the amount of control for path hunting. Initially, the space‐division multistage switching network is described and then path hunting methods which are used for evaluation are examined. The results of evaluating the amount of control for path hunting are described and consideration is given to switching networks which are most favorable with respect to the amount of control for path hunting.
Thin film γ‐Fe2O3 recording disk
Authors: Terada Akira , Ishii Osamu , Shinohara Masayoshi , Nakagawa Takehiko
Published: July 2007

An α‐Fe2O3 thin film was sputtered onto an Al‐Mg substrate, after which it was transformed to γ‐Fe2O3 by reduction and oxidation and a magnetic memory disk was fabricated. The following results were obtained with regard to these processes: (1) The processing temperature must be below 330°C to maintain the initial surface state of the substrate. (2) If an α‐Fe2O3 film is reduced at 300°C for a few hours and oxidized in air, a homogeneous γ‐Fe2O3 film is obtained. (3) Addition of Ti to the film stabilizes the coercive force and broadens the acceptable conditions for reduction. A γ‐Fe2O3 film, to which Ti and Co have been added, has the following magnetic properties: residual magnetic flux density 2.5 kGs, coercive force 700 Oe, rectangular hysteresis ratio 0.8, coercive squareness 0.76, and film thickness 0.1 ‐ 0.2 μm. (4) Coercive force and demagnetization caused by heating and pressure are as stable as those of an ordinary sprayed magnetic memory medium. A γ‐Fe2O3 thin film disk, processed in the above‐described manner, can have a memory density of 104 − 105 bit/mm2.
Fluorescent lamp modelling for voltage fluctuations
Authors: Carrillo C. , Cidrás J.
Published: July 2007

The wide use of fluorescent lamps means their influence on the power system needs to be studied. A set of models that enables the evaluation of the electrical behaviour during steady state is presented in this paper. These models have different levels of complexity; starting by taking into account all the non‐linearities of the lamp, passing through neglecting the non‐linearities of the reactance, supposing the voltage wave shape of the tube to be square and, finally, treating the variations in the RMS source voltage as an steady‐state phenomenon. The most complex model needs an iterative algorithm to get results, however analytical expressions can be achieved with the other models. Several situations can be analysed with the different models but special attention is paid to the sinusoidal voltage source and the modulated voltage source cases. Also, the study presented in this paper is focused on obtaining the waveshape of current, voltage and power in the tube. These waveforms allow the study of the normal steady‐state functioning and the flicker phenomena. In this paper the simulation results for the above models in the two kinds of situations are shown. As a result, a performance test between the models is made and it is used to validate them.
Variation power, variation currents: Physical background and compensation rules
Authors: Depenbrock M.
Published: July 2007

Derived from instantaneous power and average power the instantaneous power currents as well as the instantaneous active currents are clearly defined under steady state conditions. As a consequence instantaneous active power is also defined without any ambiguity. It is shown that if there is any difference between instantaneous power and instantaneous active power the apparent power becomes larger than the absolute value of the active power. Furthermore the rules are derived whether a power oscillation should be compensated or not and what energy storage capability of the compensator is then necessary.
Transactions evaluation and unit commitment in a bilateral electricity market using genetic algorithms
Authors: Mashhadi H. R. , Haubrich H.‐J. , Nießen S. , Modir Shanechi M. H.
Published: July 2007

Short term optimal operation planning and the evaluation of multiple power transactions (scheduled contracts for power exchange at a specific time interval) in a deregulated environment based on a bilateral market model is a complex optimization problem for the planning personnel of electric utilities. With regard to time dependent constraints and costs in unit commitment (UC), the transaction evaluation problem and UC are coupled and therefore must be solved simultaneously. In this paper a new solution method based on genetic algorithm (GA) is presented. Due to the flexibility of GA, it is possible to select optimal transactions within the UC algorithm. The basic idea of the new method is to find an optimal load curve by means of an evolutionary process using an optimal combination of proposed transactions simultaneous with optimal scheduling of generation units. The capabilities of this approach are illustrated by means of a 26‐unit system with a set of proposed transactions that includes exchange with pump storage units and various forms of transactions such as peak, off‐peak and base load.
Robust intelligent control of a speed sensorless induction motor
Authors: Denaï M. A. , Attia S. A.
Published: July 2007

This paper reports results of recent applications of intelligent control techniques to a field oriented induction machine. Induction motors are characterised by complex, highly non‐linear and time‐varying dynamics and inaccessibility of some states and outputs for measurements. The advent of vector control techniques has partially solved induction motor control problems because they are sensitive to drive parameter variations and performance may deteriorate if conventional controllers such as PID are used. With fuzzy logic and neural networks based control‐lers, uncertainties in the plant parameters and non‐linearities can be dealt with more efficiently than model‐based techniques. However, a commonly known disadvantage of these methods is the lack of systematisarion and rigorous design tools. Hybrid control architectures, combining control theory with artificial intelligent tools can solve efficiently complex control problems. Three control approaches are developed and applied to adjust the speed of the drive system. The first control design combines the variable structure theory with fuzzy logic concept. In the second approach neural networks are used in an internal model control structure. Finally, a fuzzy state feedback controller is developed based on pole placement technique. A simulation study of these methods is presented. The effectiveness of these controllers is demonstrated for different operating conditions of the drive system.
Optimal capacitors on‐line operation on distribution networks by an integrated control system based on local neurocontrollers
Authors: Arces I. , Ippolito M. G. , Morana G.
Published: July 2007

This work proposes a contribution to the problem of an optimal control of switched capacitor banks installed in radial distribution networks, by studying the possibility of adopting an integrated control strategy based on the use of neural local controllers able to manage the status of every compensation bank. In order to analyse the feasibility of this solution, the kind of control proposed was implemented in a particular study case, which allowed to compare the performance of a set of local neurocontrollers with the results of a centralized optimisation procedure, for different conditions of load and network configuration.
Alternative modes of deficit financing and endogneous monetary and fiscal policy in the U.S.A. 1923–1982
Authors: Turnovsky Stephen J. , Wohar Mark E.
Published: July 2007

This paper first investigates the effects of alternative modes of deficit financing on the unemployment rate, the inflation rate and the real interest rate, within the framework of a small complete macroeconomic model. Secondly, it examines the nature of monetary and fiscal reaction functions. The two periods 1923–1960 and 1961–1982 are considered, with substantial differences in behaviour and policy being shown to exist between them. The most important conclusion is that long‐run monetary neutrality properties shown to exist over the latter period are not intrinsic to the U.S. economy, but rather are the result of the stabilization policies being conducted over that period.
A quantitative reassessment of the purchasing power parity hypothesis: Evidence from Norway and the United Kingdom
Authors: Edison Hali J. , Klovland Jan Tore
Published: July 2007

Annual data from Norway and the United Kingdom from 1874 to 1971 are used to reassess the empirical performance of the purchasing power parity (PPP) doctrine. The simple version of the PPP relationship is supported by the data only if different short‐run dynamics during a floating‐rate period 1914–1928 is allowed for. Two sets of factors were found to be important in amending the simple PPP model. These were short‐run cyclical variables affecting the adjustment towards the PPP equilibrium relationship and long‐run structural factors such as productivity and terms of trade. Within this expanded model the proportionality between the exchange rate and relative price levels could not be rejected.
A stochastic frontier cost function for residential child care provision
Authors: Hughes Michael D.
Published: July 2007

Within a public authority (the firm), there are often several production units. Costs and policy formulation are concerned with the units themselves, though inefficiency might arise at both the firm and unit levels. A stochastic frontier cost function is developed and estimated to describe one such situation where the firms are English local authorities and the production units are homes providing residential care for children. Measures of inefficiency are found for individual authorities.
Choice of employment status and the wages of employees and the self‐employed: Some further evidence
Authors: Gill Andrew M.
Published: July 2007

Using US data drawn from the 1978 young men NLS sample, this paper replicates a key finding reported by Rees and Shah in their analysis of self‐employment using large‐scale British data. A wage equation, which allows for sample selectivity, is estimated for subsamples of employees and the self‐employed. Despite differences between the data sets and the variables analysed, the NLS results support Rees and Shah's conclusion that there is positive selection bias in the observed earnings of employees.
Alternative specifications of the error process in the stochastic simulation of econometric models
Authors: Sterbenz Frederic P. , Calzolari Giorgio
Published: July 2007

This paper analyses the stochastic simulation of econometric models using three different methods for specifying the probability distribution of the structural error terms. The impact of these different assumptions on the simulation bias and model variance is explored empirically. Monte Carlo variance reduction techniques are used to distinguish the effects of the different specifications.
Persistent deficits and the market value of government debt
Authors: Smith Gregor W. , Zin Stanley E.
Published: July 2007

This paper investigates whether postwar Canadian public financial policy satisfies a borrowing constraint. Direct tests of the present‐value relation suggested by this constraint shed light on the sustainability of current policy. We examine monthly data on Canadian federal government finances using tests for cointegration. The finding is that the joint behaviour of real debt and real surpluses is inconsistent with intertemporal budget balance for the government. One interpretation of this finding is that the government is systematically paying real returns to bondholders by issuing further debt. Alternatively, bondholders may expect the government to finance future interest payments from a source other than primary surpluses, e.g. the sale of physical assets.
A review of stata 2.1
Authors: Peterson Steven P.
Published: July 2007

STATA 2.1 offers state‐of‐the‐art data management features and statistical procedures capable of handling very large data sets. Its graphics capabilities are excellent as well. Although the package performs a respectable array of econometrics procedures quickly and easily, its menu of available techniques is relatively weak compared to existing econometrics packages. However, since STATA plans a new release to be aimed at the econometrics market, this shortcoming could be mitigated substantially in future versions.
On Bayesian routes to unit roots
Authors: Schotman Peter C. , Van Dijk Herman K.
Published: July 2007

This paper is a comment on P. C. B. Phillips, ‘To criticise the critics: an objective Bayesian analysis of stochastic trends’ [Phillips, (1991)]. Departing from the likelihood of an univariate autoregressive model different routes that lead to a posterior odds analysis of the unit root hypothesis are explored, where the differences in routes are due to the different choices of the prior. Improper priors like the uniform and the Jeffreys prior are less suited for Bayesian inference on a sharp null hypothesis as the unit root. A proper normal prior on the mean of the process is analysed and empirical results using extended Nelson‐Plosser data are presented.
‘Objective’ bayesian unit root tests
Authors: Koop G.
Published: July 2007

Due to weaknesses in traditional tests, a Bayesian approach is developed to investigate whether unit roots exist in macroeconomic time‐series. Bayesian posterior odds comparing unit root models to stationary and trend‐stationary alternatives are calculated using informative priors. Two classes of reference priors which are informative but require minimal subjective prior input are used. In this sense the Bayesian unit root tests developed here are objective. Bayesian procedures are carried out on the Nelson–Plosser and Shiller data sets as well as on generated data. The conclusion is that the failure of classical procedures to reject the unit root hypothesis is not necessarily proof that a unit root is present with high probability.
How does the benefit effect vary as unemployment spells lengthen?
Authors: Narendranathan W. , Stewart M. B.
Published: July 2007

This paper investigates how the effect of income while unemployed on the probability of an individual leaving unemployment varies with the length of time that the individual has been unemployed. We examine this question in the context of a variety of alternative econometric models. We extend the Proportional Hazards model with unrestricted baseline hazard to one in which there are unrestricted effects of a subset of the explanatory variables and also consider models that can be estimated as series of binary response models. The proportional hazard restrictions are rejected for the sample of British unemployed men analysed and in the binary sequence framework Logit and Probit models based on symmetric distributions dominate (in likelihood terms) the Extreme Value form model implied by extension of the Proportional Hazards formulation. Logit models with a flexible form for the duration dependence which also incorporate unobserved heterogeneity in a flexible way are estimated. The results for all formulations indicate a rapidly declining effect of unemployment income as a spell lengthens, with no significant effect for the long‐term unemployed. The preferred specifications which allow for omitted heterogeneity indicate no significant effect after about 5 months, and this result is robust to the inclusion or exclusion of previous labour‐market experience variables and to the choice of mixing distribution.
Alternative procedures for converting qualitative response data to quantitative expectations: An application to Australian manufacturing
Authors: Smith Jeremy , McAleer Michael
Published: July 2007

This paper analyses and extends alternative procedures for converting qualitative expectations responses to quantitative expectations. A number of conversion procedures is investigated, including the probability model, the time‐varying parameter probability model, and the regression approach. The informational content of the survey expectations is compared with simple time series models. It is found that the expectations models are superior for many series, both in terms of producing lower forecast root mean square error (RMSE) values and in detecting turning points in the actual data. Survey expectations are also tested for rational expectations in aggregate using the orthogonality test.
Spectral tests of the martingale hypothesis for exchange rates
Authors: Fong Wai Mun , Ouliaris Sam
Published: July 2007

A new family of spectral shape tests was proposed recently by Durlauf (1991) for testing the martingale hypothesis. Unlike the widely used variance ratio test, spectral shape tests are consistent against all stationary non‐white‐noise alternatives from the martingale null. In this paper we examine the finite sample properties of the spectral shape tests and find that the tests have good size and power properties even for small samples. We apply the tests to examine the martingale hypothesis for five major currencies vis‐à‐vis the US dollar for the period 1974–89. The results indicate that most currencies violate the martingale hypothesis. It appears that some rejections are due to long‐memory influences.
Cyclical output, cyclical unemployment, and Okun's coefficient: A new approach
Authors: Weber Christian E.
Published: July 2007

Estimates of Okun's coefficient are obtained using new estimates of cyclical GNP and cyclical unemployment rates for the post‐war USA. Empirical estimates of the coefficient are near —0.25, somewhat smaller in magnitude than other recent estimates obtained applying similar econometric techniques to different estimates of cyclical output and unemployment. Tests fail to reject the hypothesis of parameter stability across an hypothesized break between the third and fourth quarters of 1973, suggesting similar relationships between cyclical output and unemployment both before and after the supply shocks of the 1970s.