Journal Of Materials Science Research Articles

Tribute Professor Andrew Keller

This special issue acknowledges the seminal contribution of Professor Andrew Keller to polymer science and brings together contributions from his many colleagues and friends as a tribute to his memory. It is particularly appropriate that the Journal of Materials Science publishes such a memorial, as Andrew played a key role in the foundation and development of the Journal to its present position at the international forefront of the field. Andrew was a member of the enlightened group of Editors, chaired by Robert Cahn, which launched Journal of Materials Science in 1966. At that time, the concept of Materials Science as an integrated discipline covering the structure, properties processing and application of all materials was novel. From the outset, Andrew was responsible for nurturing and encouraging the submission of polymer papers and for ensuring appropriate refereeing, much of which he performed personally or through his group in Bristol. Given his enthusiasm and insight, many authors found their papers considerably improved by the quality of the refereeing process.

Comment on “Mechanical properties in the initial stage of sintering”

In a paper entitled Mechanical properties in the initial stage of sintering (Journal of Materials Science 30 (1995) 1863), Arato, Besenyei, Kele and Weber have proposed a model to describe the Young's modulus of sintered materials as a function of porosity. The proposed model, even if it is able to predict actual experimental trends over a wide range of porosity, suffers from a theoretical inconsistency at zero porosity. Consequently, it should be used with care, and probably only in the initial stage of sintering, as indicated by the title of the article.

Scale effects in friction of single–asperity contacts. II. Multiple–dislocation–cooperated slip

In this paper we explore the second transition in the mechanism of frictional slip of single–asperity contacts, which takes place at large contact sizes. This is a transition from single–dislocation–assisted (SDA) slip to multiple–dislocation–cooperated (MDC) slip. It is found that the friction stress is controlled by dislocation nucleation for SDA slip, and by dislocation mobility for MDC slip. A model of concentric dislocation loops is introduced to analyse dislocation pile–up processes and their relationship to the friction stress. Dislocations are stabilized to be piled up as a result of the non–zero effective Peierls stress of the interface. The analysis shows that slip occurs when the condition for the nucleation of a new dislocation and the condition for destabilizing the leading dislocation of the pile–up are simultaneously satisfied. It is also shown that, as the contact size increases, the friction stress approaches asymptotically a constant value equal to the effective Peierls stress of the interface. This result is in agreement with reported experimental results in the surface force apparatus (SFA). The case of a large number of dislocations in the pile–up is studied via an asymptotic analysis, a key concept of which is the existence of a dislocation–free zone that controls the dislocation nucleation process. The analysis provides the connection between the discrete dislocation model and the continuous cohesive zone model of single–asperity friction.

Scale effects in friction of single–asperity contacts. I. From concurrent slip to single–dislocation–assisted slip

A micromechanical dislocation model of frictional slip between two asperities is presented. The model suggests that when the contact radius is smaller than a critical value, the friction stress is constant, of the order of the theoretical shear strength, in agreement with reported atomic force microscope (AFM) friction experiments. However, at the critical value there is a transition beyond which the friction stress decreases with increasing area, until it reaches the second transition where the friction stress gradually becomes independent of the contact size. This is in contrast to previous theories, which assume that the friction stress is always independent of the size. The present model also predicts that the mechanisms of slip are size dependent. Before the first transition, the constant friction stress is associated with concurrent slip without the aid of dislocation motion. The first transition corresponds to the minimum contact size at which a single dislocation loop is nucleated and sweeps through the whole contact interface, resulting in a single–dislocation–assisted (SDA) slip. This mechanism is predicted to prevail for a wide range of contact sizes, from 10 nm to 10 µm in radius for typical dry adhesive contacts; however, there are no available experimental data in this size range. The second transition is found to be caused by the effective Peierls stress which stabilizes the dislocation loop within the contact region, resulting in dislocation pile–ups. Beyond the second transition, slip is assisted by cooperative glide of dislocations in the pile–up. For sufficiently large contacts the mechanism of cooperative glide induces a size–independent friction stress, in agreement with observations in surface force apparatus (SFA) friction experiments. This paper (Part I) addresses the first transition: from concurrent slip to SDA slip. The second transition is analysed in a companion paper (Part II).

Late Thrombosis After Radiation

Five years after Condado et al1 first treated human coronary arteries with brachytherapy, there is ongoing clinical investigation into its safety and efficacy in preventing restenosis. As with any novel technique, unexpected complications may dampen early high expectations and result in pessimism and skepticism. However, time, experience, and complete data analysis will determine the reality. Costa and coworkers2 may be reacting prematurely by reporting a new phenomenon in interventional cardiology entitled “late, sudden thrombosis after PTCA plus radiotherapy.” They report 6 (6.6%) of 91 patients who presented with late total occlusion/thrombosis at angiographic follow-up; these patients were enrolled into different radiation protocols using different β-emitters at different prescribed doses. Late total occlusion or late thrombosis is a valid concern, especially when associated with acute myocardial infarction (MI). However, can we really draw any conclusion from 6 heterogeneous case reports taken from a small cohort of patients in the absence of a control group? Is this announcement based on too few data, and is it premature? An editorial based on a Brief Rapid Communication mandates the editorialist to gather additional information, disclose his own insights, and provide the readers (the jury in this case) with as much information as possible. Acute thrombosis occurs during or early after intervention, and subacute thrombosis occurs within the subsequent 30 days. Both usually present with unstable symptoms and angiographic evidence of thrombus. However, the definition of late thrombosis may be problematic. It may not present with symptoms. It may be detected only when follow-up angiography shows a late total occlusion, which could also be the result of progressive intimal hyperplasia. Late total occlusion/thrombosis should be defined as any angiographically documented total occlusion >30 days after the procedure. For patients who have a patent treatment site at 6 months and subsequently develop a total …

Effective conductivity of loaded granular materials by numerical simulation

Thermal (or electrical) conduction through a stationary, random close packed granular material is studied by numerical simulation. The particles are smooth uniform spheres with either point contact...

Macroscopic and microscopic subdivison of a cold–rolled aluminium single crystal of cubic orientation

An aluminium single crystal of cube orientation has been rolled to 15, 30 and 50% reductions under controlled homogeneous rolling conditions. The deformation structure of the rolled specimens was investigated by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) over several scales of magnification. The local crystallographic orientations have been measured by an automatic electron back scattering patterns (EBSP) technique and a semiautomatic TEM method. Orientation image maps based on the local orientation data have been used to reveal the evolution of the deformation structure during rolling. It is observed that by an opposite rotation around transverse direction (TD) the crystal was subdivided into four macroscopic bands, termed matrix bands in the present paper, which are parallel to the rolling plane. Between the four bands there are three transition bands in which the orientation changes continuously from that of a matrix band to that of the adjoining one. A model based on the idea of location–dependent shear strain caused by geometric and friction effects together with a plasticity analysis has been used to explain the macroscopic subdivision of the crystal. In addition to the macroscopic subdivision, a microscopic subdivision by the formation of cell–blocks within the matrix bands and a cell structure within transition bands has also been observed. A difference related to shear amplitude difference between the active slip systems changing continuously across the crystal has been observed. Both the macroscopic orientation of the dislocation boundaries and the misorientation angles and axes across dislocation boundaries are analysed and it is found that Frank9s formula is a useful tool in analysing the dislocation boundaries formed during deformation.

A plastic flow-induced fracture theory for fatigue crack growth : Ding, H.-Z. and Xing, X.-S. Journal of Materials Science (1996) 31, 4099–4103

A plastic flow-induced fracture theory for fatigue crack growth : Ding, H.-Z. and Xing, X.-S. Journal of Materials Science (1996) 31, 4099–4103

Acoustic emission data on delayed damage processes in the vicinity of defects in fibre-reinforced plastics : 54843 Tishkin, A.P.; Gubanova, G.N.; Leksovski, A.M.; Yudin, V.E. Journal of Materials Science, Vol. 29, No. 3, pp. 632–639 (1 Feb. 1994)

Acoustic emission data on delayed damage processes in the vicinity of defects in fibre-reinforced plastics : 54843 Tishkin, A.P.; Gubanova, G.N.; Leksovski, A.M.; Yudin, V.E. Journal of Materials Science, Vol. 29, No. 3, pp. 632–639 (1 Feb. 1994)

Acoustic emission analysis and small-angle x-ray scattering from microcracks during deformation of ETFE composites : 53334 Kraus, R.; Payer, A.; Wilke, W. Journal of Materials Science, Vol. 28, No. 15, pp. 4047–4052 (1 Aug 1993)

Acoustic emission analysis and small-angle x-ray scattering from microcracks during deformation of ETFE composites : 53334 Kraus, R.; Payer, A.; Wilke, W. Journal of Materials Science, Vol. 28, No. 15, pp. 4047–4052 (1 Aug 1993)

Acoustic emission from stress corrosion cracks in aligned GRP : 36692 Kumosa, M.; Hull, D.; Price, J.N. Journal of Materials Science, Vol. 22, No. 1, pp. 331–336 (Jan. 1987)

Acoustic emission from stress corrosion cracks in aligned GRP : 36692 Kumosa, M.; Hull, D.; Price, J.N. Journal of Materials Science, Vol. 22, No. 1, pp. 331–336 (Jan. 1987)

Serotonin-dopamine interaction and its relevance to schizophrenia.

The therapeutic success of clozapine and risperidone has focused attention on the interaction between serotonin and dopamine systems as an avenue for superior therapeutics in schizophrenia. The authors review the neurobiological basis for this interaction and its clinical relevance. The authors synthesized information from more than 100 published articles obtained through electronic and bibliography-directed searches. The serotonin system inhibits dopaminergic function at the level of the origin of the dopamine system in the midbrain as well as at the terminal dopaminergic fields in the forebrain. Serotonergic antagonists release the dopamine system from this inhibition. This disinhibition of the dopamine system in the striatum may alleviate neuroleptic-induced extrapyramidal symptoms, and a similar disinhibition in the prefrontal cortex may ameliorate negative symptoms. However, the benefits of combined serotonergic-dopaminergic blockade may be observed in only a narrow dose range and may be lost with doses that produce suprathreshold dopaminergic blockade. Serotonergic modulation of dopaminergic function provides a viable mechanism for enhancing therapeutics in schizophrenia, but much remains unclear. Future research will have to establish the existence of this interaction in humans in vivo, specify the conditions under which it leads to optimal therapeutic benefits, and explore the possibility of using specific serotonergic treatments as flexible adjuncts to typical neuroleptics, rather than the present trend toward using single drugs with combined actions.

The Romance of Victorian Natural History. Lynn L. Merrill

Previous articleNext article No AccessBook ReviewsThe Romance of Victorian Natural History. Lynn L. Merrill Ann B. ShteirAnn B. Shteir Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Isis Volume 81, Number 4Dec., 1990 Publication of the History of Science Society Article DOIhttps://doi.org/10.1086/355604 Views: 3Total views on this site Citations: 2Citations are reported from Crossref Copyright 1990 History of Science Society, Inc.PDF download Crossref reports the following articles citing this article:Amy M. King The Divine in the Commonplace, 22 (Jul 2019).https://doi.org/10.1017/9781108631952Ismeli Alfonso, Cuauhtemoc Maldonado, Gonzalo Gonzalez, Arnoldo Bedolla Effect of Mg content and solution treatment on the microstructure of Al-Si-Cu-Mg alloys, Journal of Materials Science 41, no.77 (Mar 2006): 1945–1952.https://doi.org/10.1007/s10853-006-4494-y

Ultrasonic measurements during early-stage hydration of ordinary Portland cement: 39577 Kim, H.C.; Yoon, S.S. Journal of Materials Science, Vol. 23, No. 2, pp. 611–616

Ultrasonic measurements during early-stage hydration of ordinary Portland cement: 39577 Kim, H.C.; Yoon, S.S. Journal of Materials Science, Vol. 23, No. 2, pp. 611–616

Review — acoustic microscopy of low-ductility materials : Fatkin, D.G.P.; Scruby, C.B.; Briggs, G.A.D. Journal of Materials Science, Vol. 24, No. 1, pp. 23–40 (Jan. 1989)

Review — acoustic microscopy of low-ductility materials : Fatkin, D.G.P.; Scruby, C.B.; Briggs, G.A.D. Journal of Materials Science, Vol. 24, No. 1, pp. 23–40 (Jan. 1989)

Review — acoustic microscopy of low-ductility materials Fatkin, D.G.P.; Scruby, C.B.; Briggs, G.A.D. Journal of Materials Science, Vol. 24, No. 1, pp. 23–40 (Jan. 1989)

Review — acoustic microscopy of low-ductility materials Fatkin, D.G.P.; Scruby, C.B.; Briggs, G.A.D. Journal of Materials Science, Vol. 24, No. 1, pp. 23–40 (Jan. 1989)

Ultrasonic velocities in textured metals: Hinz, D.C.; Szpunar, J.A. Journal of materials science, vol. 24, no. 1, pp. 45–52 (Jan. 1989)

A brief review is presented of the calculation of elastic properties in textured metals with a view toward ultrasonic velocity studies. Proceeding from the linearized wave equation for elastic materials, the propagation of elastic waves is analysed from the point of view of plane and curved wavefronts to develop an understanding of the roles of phase and group velocities. This theory is applied to the calculation of the three polarizations of ultrasonic waves in Fe/Si transformer steels of various textures.

EXPERIMENTAL STUDIES OF THE ELECTRON STRUCTURE OF HIGH-Tc SUPERCONDUCTORS

International Journal of Modern Physics BVol. 03, No. 07, pp. 973-1000 (1989) ReviewsNo AccessEXPERIMENTAL STUDIES OF THE ELECTRON STRUCTURE OF HIGH-Tc SUPERCONDUCTORSE.Z. KURMAEV and L.D. FINKELSTEINE.Z. KURMAEVInstitute of Metal Physics, USSR Academy of Sciences, Ural Division, Sverdlovsk, GSP-170, USSR and L.D. FINKELSTEINInstitute of Metal Physics, USSR Academy of Sciences, Ural Division, Sverdlovsk, GSP-170, USSRhttps://doi.org/10.1142/S0217979289000713Cited by:6 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail You currently do not have access to the full text article. Recommend the journal to your library today! FiguresReferencesRelatedDetailsCited By 6References1 Jan 1995Valency of copper in 123 oxidesN. S. Raman, B. Viswanathan and T. K. Varadarajan20 March 1992 | Journal of Materials Science, Vol. 27, No. 23The electronic structure of single crystal YBa2Cu3O7–δ studied by polarized Cu Kβ2,5 X-ray emissionW. Czolbe, U. Dick, G. Dräger and K. Fischer1 Nov 1992 | physica status solidi (b), Vol. 174, No. 1X-ray-photoemission-spectroscopy study of the surface deterioration of Bi2Sr2CaCu2O8 and Bi1.7Pb0.3Sr2CaCu2O8 single crystals at 26 KA. Balzarotti, M. De Crescenzi, N. Motta, F. Patella and A. Sgarlata et al.1 May 1991 | Physical Review B, Vol. 43, No. 13Superconductivity in the (Gd1−xPrx)Ba2Cu3O7−δ systemZ. Tomkowicz, K. ła̧tka, A. Szytuła, A. Bajorek and M. Bałanda et al.1 Mar 1991 | Physica C: Superconductivity, Vol. 174, No. 1-3A photoemission study (XPS and UPS) of the superconductor ErBa2Cu4O8 and comparison with YBa2Cu3O7-?(??0,1)P. Adler, H. Buchkremer-Hermanns and A. Simon1 Oct 1990 | Zeitschrift f�r Physik B Condensed Matter, Vol. 81, No. 3 Recommended Vol. 03, No. 07 Metrics History Received 14 April 1989 PDF download

Acoustic emission from stress corrosion cracks in aligned GRP : Kumosa, M.; Hull, D.; Price, J.N. Journal of Materials Science, Vol. 22, No. 1, pp. 331–336 (Jan. 1987)

Acoustic emission from stress corrosion cracks in aligned GRP : Kumosa, M.; Hull, D.; Price, J.N. Journal of Materials Science, Vol. 22, No. 1, pp. 331–336 (Jan. 1987)

Study of the oxidation behaviour of 9Cr-1 Mo steel using the acoustic emission technique : Jha, B.B.; Khanna, A.S.; Raj, B. Journal of Materials Science, Vol. 22, No. 8, pp. 2823–2827 (Aug. 1987)

Study of the oxidation behaviour of 9Cr-1 Mo steel using the acoustic emission technique : Jha, B.B.; Khanna, A.S.; Raj, B. Journal of Materials Science, Vol. 22, No. 8, pp. 2823–2827 (Aug. 1987)