From: calendar@ALMADEN.IBM.COM (IBM Almaden Research Center Calendar)
Newsgroups: ba.seminars
Subject: IBM ARC seminars 13 - 17 APR 92
Date: 10 Apr 92 01:33:20 GMT


                     IBM Almaden Research Center
                           650 Harry Road
                       San Jose, CA 95120-6099

                              CALENDAR
                          April 13-17, 1992


04/13 - MOLECULAR APPROACH TO UNDERSTAND THE MISCIBILITY OF POLYMER
BLENDS
Dr. H. E. Yang, Kodak Research Labs, Rochester, New York

Polym. Sci. & Tech. Sem.    Mon., April 13    10:00 a.m.    Room: E2-450

Fourier transform-infrared (FT-IR) spectroscopy is an appropriate
technique to understand the nature and magnitude of the intermolecular
forces of polymer blends, which drive the system to miscibility.  This
technique has been applied to study the molecular interactions for
miscible blend of polystyrene (PS) and tetramethyl bisphenol A
polycarbonate (TMPC) as a function of composition and temperature, and
for an immiscible blend of PS and bisphenol A polycarbonate (PC).  The
results show that the major interaction of PS/TMPC blend arises from the
phenyl ring of PS and the carbonyl group of TMPC, and there is no
interaction for PS/PC blend.  The detailed discussion about the shift
and width of the interactional bands will be presented.  Further, the
substituent effects on the miscibility of the polymer blends in terms of
the molecular interactions and the chemical structures will be
discussed.
Host:  A. Yang


04/13 - THE LINEAR ALGEBRA BOUND AND COMBINATORIAL EXTREMA
L. Babai, University of Chicago

Comp. Sci. Sem.     Mon., April 13     10:30 a.m.     Room: B2-307

Replacing probabilistic existence proofs with determinsitic
constructions is at the heart of many problems in computation theory.
Combinatorial extrema, in turn, provide methods which have been used
with some success in this area.  A number of results in extremal
combinatorics are derived from the following simple observation which we
refer to as the "linear algebra bound":  If m vectors of an
n-dimensional vector-space are linearly independent, then m <= n.
Starting with Bose's proof of Fisher's inequality, the linear algebra
bound has been developed into a powerful method over the past four
decades.  The art in applying the linear algebra bound is in associating
vectors with combinatorial objects in an appropriate way.  We shall
briefly survey some of the highlights of this development and mention
some recent result obtained in joint work with N. Alon and H. Suzuki.
Host:  B. Simons


04/13 - PSA: A GENERALIZED TRANSACTION PROCESSING MECHANISM TO SUPPORT
COOPERATIVE GROUP WORK IN DISTRIBUTED SYSTEMS
Prof. Dr. H. Wedekind, Comp. Sci. Dept., Univ. of Erlangen, Germany

Comp. Sci. Sem.     Mon., April 13     11:00 a.m.     Room: Aud A

For traditional data base system applications like banking and
accounting, transactions have proven to be an ideal means of resource
management. In new applications like CAD/CAM or concurrent engineering,
however, the classical transaction concept limits the degree of user
cooperation significantly due to the underlying concept of transaction
serialization. Long transactions and tentative data values, which are
typical for non-standard applications, are not sufficiently supported by
traditional data base systems and transaction processing mechanisms.

"Committed" is a central concept of modal logic and data base systems as
well. In order to provide a better support of cooperative group work
within a data base system, inferences are analyzed in order to
distinguish data base transactions from problem solving activities
(PSA's).  PSA's are a higher-level transaction concept that uses data
base transactions for resource management. User cooperation is supported
by new synchronization concepts introduced with the PSA approach.  Plans
in an introductory and executive mode are needed for synthesis.  The PSA
concept is developed within the theory of spheres of control, from which
the concept "transaction" was formerly derived. It is shown that PSA's
are a generalization of the traditional transaction concept.
Hosts:  T. Ruf and Kwan Y. Wong


04/13 - CHARGE TRANSFER AND ADHESION AT DISSIMILAR MATERIAL INTERFACES
MEASURED WITH THE SURFACE FORCE APPARATUS
D. T. Smith, National Institute of Standards and Technology

Phys. Sci. Sem.     Mon., April 13     11:00 a.m.     Room: G2-301

A study has been made of the adhesion between dissimilar ceramic
materials (silica and mica) brought into molecular contact and then
separated in a dry inert gas environment.  When two initially uncharged
surfaces were brought into contact, the force between them was found to
be weak (a van der Waals attraction).  When the two materials were
separated, it was found that electric charge had transferred from one to
the other, with the silica acquiring a negative charge, and mica an
equal and opposite positive charge.  In situ electrometer measurements
revealed surface charge densities as high as 20 mC/m2 after contact.  A
long-ranged attractive force, which was strong enough to deform the
surface, was measured between the oppositely-charged surfaces.  Discrete
discharges were observed at certain surface separations.  A simple model
is presented to explain the measured dependence of the force on surface
separation.  Since the separation of the two materials resembles an
interfacial fracture process, the same model is used to calculate the
contribution of the electrostatic force to the fracture energy.  The
result is substantial: about 6 J/m2 for the silica-mica interface.  It
is suggested that electrostatic forces may play an important role in
composite fracture in dry environments.
Host:  G. M. McClelland


04/13 - OPTICAL DATA PROCESSING WITH BACTERIORHODOPSIN AND ITS
GENETICALLY MODIFIED VARIANTS
Ch. Braeuchle, Univ. of Munich, Inst. of Physical Chemistry, Germany

Stor. Syst. & Tech./     Mon., April 13     1:30 p.m.     Room: J2-609
Polym. Sci. Seminar

The field of molecular electronics is characterized by an attempt to
engineer and use devices on a molecular level.  Supramolecular chemistry
is one way to produce such molecular devices.  However, long before
supramolecular chemists tried to synthesize highly organized artificial
systems, nature has produced and optimized biological systems on a
molecular device level.  Bacteriorhodopsin (BR) and its function as
lightdriven proton pump is only one of many examples.  It will be shown
how BR and its genetically modified variants can be used in holographic
techniques, optical phase conjugation, dynamic optical filtering and
optical pattern recognition.
Hosts:  E. Marinero and W. E. Moerner


04/13 - DATA AND ACTIVITY MANAGEMENT IN DISTRIBUTED APPLICATION SYSTEMS
B. Reinwald, University of Erlangen - Nuremberg, Germany

Comp. Sci. Sem.     Mon., April 13     3:00 p.m.     Room: CRB2/050

In order to achieve a common task in a distributed application system
like computer integrated manufacturing or office automation, various
application sites running pre-existing turn-key systems have to be
integrated both on activity and data level. Considering well-structured
cooperative work with predefined procedure semantics, three aspects
arise which are not manageable by current non-standard database systems:

1.  application-oriented, replicated data allocation with asynchronous
    data actualization according to the current state of the
    application;

2.  system-enforced triggering of activities according to application-
    defined semantics;

3.  tight coordination of activity and data level in order to optimize
    distributed data management.

In the talk, some severe shortcomings of traditional approaches to
distributed data management are shown using a sample application in the
area of computer integrated manufacturing. A more flexible mechanism
which enables an event-oriented actualization of replicated data is
developed. As the actualization parameters (which data are used at which
site and when) depend on the current state of procedure execution, an
application-oriented execution model of well-structured cooperative work
in distributed computing environments is presented. The execution model
is based on message-type tasks which pass between activities and enforce
the triggering of activities. At both levels, activity and data, a
general purpose trigger system is used for event-oriented computation.
Hosts: T. Ruf and Kwan Y. Wong


04/14 - FREE RADICAL TECHNIQUE TO PREPARE  alpha  omega  END-FUNCTIONAL
POLYMERS AND BLOCK COPOLYMERS VIA THERMAL INIFERTERS
Prof. G. Clouet, Institut Charles Sadron, Strasbourg Cedex, France

Polym. Sci. & Tech. Sem.    Tues., April 14    10:00 a.m.    Room: J2-601

The constitutive elements of a polymer determine its local physical and
chemical properties.  The overall structure of a polymer, in which the
elements are properly positioned, modulates its general properties.  For
these reasons, the control of polymer architecture has long been the
focus in our Institute.  Block copolymers-developed with this
strategy-were produced by the laboratory for the first time by means of
anionic polymerization more than 20 years ago.  It allows the
simultaneous growth of all the chains while maintaining a living end, on
which A and B monomers can be added sequentially to prepare block
copolymers.  Depending on the relative block lengths, this synthesis
yields phase separation due to the repulsion between A and B blocks:
then a regular lamellar or cylindrical geometry results.  Nevertheless,
this complex technique is hard to adapt to industrial use.

In order to overcome these difficulties, we have used new radical
polymerization primers called INIFERTERs from INItiation, transFER and
TERmination.  We have developed a method based upon thiuram disulfieds,
which perform these three steps for the vinylic and dienic monomers B,
and besides allows control of the molecular weight, polymer
functionalization, and allows the synthesis of original block
copolymers.
Host:  T. Russell


04/14 - CONTRAST MECHANISMS OF FRICTION FORCE MICROSCOPY
E. Meyer, University of Basel

Phys. Sci. Sem.     Tues., April 14     10:30 a.m.     Room: Aud. B

In friction force microscopy both the normal and lateral forces between
probing tip and sample are simultaneously measured.  The advantage of
this method is the ability to compare the normal force maps (associated
with topography) to the lateral force maps on a nanometer scale.  In
many cases the lateral force map represents a derivative of the
topography (e.g., in recording microfabricated structures).  However,
local variations in the friction coefficient can also be found on
inhomogeneous samples (e.g., at the interface between substrate and
adsorbate, as in Langmuir-Blodgett films).  These variations in friction
can originate from such effects as variations in material composition of
the sample of from different crystallographic orientations.
Host:  G. McClelland


04/14 - IDENTIFYING THE IMPORTANT FACTORS IN SIMULATION MODELS WITH MANY
FACTORS
Prof. J. Kleijnen, University of Tilburg, Netherlands

Comp. Sci. Sem.     Tues., April 14     1:15 p.m.     Room: G2-301

In practice, simulation models usually have a great many parameters and
input variables.  This paper presents a screening technique, which
identifies the really important factors.  The technique treats the
simulation model as a black box and uses a regression metamodel to
approximate the input/output behavior of the black box.  The metamodel
can account for fitting errors with unknown variance and for
interactions among factors.  The technique requires relatively few
simulation runs.  It applies to both random and deterministic
simulations.  The technique is demonstrated through a case study of a
complicated ecological model.
Host:  K. Wong


04/16 - CHARACTERIZATION OF ORGANOMETALLIC VAPOR PHASE EPITAXIAL GROWTH
USING IN-SITU GRAZING INCIDENCE X-RAY SCATTERING
D. Kisker, IBM Research, Yorktown Heights, New York

Phys. Sci. Sem.     Thurs., April 16     2:00 p.m.     Room: D2-450

Despite its importance for the growth of thin films of compound
semiconductors such as GaAs and InP, vapor phase epitaxial growth using
organometallic sources (OMVPE) has been limited due to the lack of
detailed understanding of the growth process.  This state of affairs has
arisen because of the lack of in-situ probes which can be applied in the
high temperature, harsh environment of chemical vapor deposition.  In
this talk, I will discuss our recent results in which we have applied
grazing incidence x-ray scattering to the in-situ study of OMVPE.
Host:  M. Toney


04/17 - SUPERPLASTICITY IN METALLIC, CERAMIC AND COMPOSITE MATERIALS
O. Sherby, Department of Materials Science, Stanford University

Phys. Sci. Colloq.     Fri., April 17     10:30 a.m.     Room: Aud. A

When crystalline solids exhibit elongations in excess of one thousand
percent, they are call superplastic.  Such materials present a whole new
approach to manufacturing structural materials.  Recent events in the
development of superplastic materials will be described.
Superplasticity has been developed in microduplex stainless steels,
mechanically alloyed aluminum, silicon carbide whisker-reinforced
aluminum alloys, aluminum-magnesium alloys, and in ultrahigh carbon
steels.  Significant advances have also been made in understanding
internal stress superplasticity; recent examples include alpha-uranium,
zinc-alumina composites and silicon carbide whisker reinforced aluminum
alloys.  In other major developments, superplastic behavior has been
developed in ferrous-laminated composites, and the mechanisms of
superplasticity have been successfully applied to consolidation of
powders.  In a major breakthrough, true ceramic materials have been
shown to be superplastic in tension tests.  Mechanisms of plastic flow
and fracture in superplastic materials will be discussed.
Host:  C. Ortiz

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For further information on individual talks, please contact the host
listed above.

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