The FORCE: A portable parallel programming language supporting computational structural mechanics

This project supports the conversion of codes in Computational Structural Mechanics (CSM) to a parallel form which will efficiently exploit the computational power available from multiprocessors. The work is a part of a comprehensive, FORTRAN-based system to form a basis for a parallel version of the NICE/SPAR combination which will form the CSM Testbed. The software is macro-based and rests on the force methodology developed by the principal investigator in connection with an early scientific multiprocessor. Machine independence is an important characteristic of the system so that retargeting it to the Flex/32, or any other multiprocessor on which NICE/SPAR might be imnplemented, is well supported. The principal investigator has experience in producing parallel software for both full and sparse systems of linear equations using the force macros. Other researchers have used the Force in finite element programs. It has been possible to rapidly develop software which performs at maximum efficiency on a multiprocessor. The inherent machine independence of the system also means that the parallelization will not be limited to a specific multiprocessor

Viral respiratory infections and the maturation of nasal immune responses in infants: the VIGALL study

The human body has an extensive defence mechanism (immune system) for coping with pathogens. It is regulated by signalling molecules called cytokines. Cytokines are produced by various cells of the immune system such as leucocytes (e.g. T-cells and macrophages) but also by nasal and pulmonary epithelial tissue. There are several different types of cytokines. Th1 cytokines are involved in the eradication of bacterial and viral pathogens, while Th2 cytokines are involved in the defence against parasites. The production of Th1 cytokines is suppressed by Th2 cytokines and vice-versa so that the production of both cytokines is kept in balance. An overproduction of Th1 cytokines is found in auto-immune disorders, while allergic disease is frequently accompanied by high Th2 cytokine production. Furthermore, pro-inflammatory cytokines can induce general inflammatory reactions, while anti¬inflammatory and regulatory cytokines may downregulate these responses. Immune responses in newborns are immature. This is seen in relatively high levels of Th2 and regulatory cytokines and low levels of Th1 cytokines compared to adults. The infant immune system matures with age. This maturation process consists of a relative increase in the production of Th1 cytokines compared to Th2 cytokines. Viral respiratory infections in infants may stimulate immune matura¬tion by their repeated Th1 stimulating effect, and thereby reduce the risk of a child developing Th2-mediated allergic disease. This hypothesis was first proposed by Professor Strachan in 1989 and is known as the ’hygiene hypothesis’.In the VI¬GALL study (VIGALL is the Dutch abbreviation for virally-mediated allergy), we examined whether respiratory infections predominantly induced by viruses may affect the maturation of the immune system and the development of allergic dis¬ease. We therefore looked to see which respiratory viruses are most prevalent in infants and what types of immune response are induced in the nos

The FORCE: A highly portable parallel programming language

Here, it is explained why the FORCE parallel programming language is easily portable among six different shared-memory microprocessors, and how a two-level macro preprocessor makes it possible to hide low level machine dependencies and to build machine-independent high level constructs on top of them. These FORCE constructs make it possible to write portable parallel programs largely independent of the number of processes and the specific shared memory multiprocessor executing them

Force user's manual: A portable, parallel FORTRAN

The use of Force, a parallel, portable FORTRAN on shared memory parallel computers is described. Force simplifies writing code for parallel computers and, once the parallel code is written, it is easily ported to computers on which Force is installed. Although Force is nearly the same for all computers, specific details are included for the Cray-2, Cray-YMP, Convex 220, Flex/32, Encore, Sequent, Alliant computers on which it is installed

Force user's manual, revised

A methodology for writing parallel programs for shared memory multiprocessors has been formalized as an extension to the Fortran language and implemented as a macro preprocessor. The extended language is known as the Force, and this manual describes how to write Force programs and execute them on the Flexible Computer Corporation Flex/32, the Encore Multimax and the Sequent Balance computers. The parallel extension macros are described in detail, but knowledge of Fortran is assumed

Triplet Exciton Dynamics in Fluorene-Amine Copolymer Films

Effect of aromaticity on triplet exciton dynamics was studied by transient absorption spectroscopy for two fluorene-based random copolymers with different aromatic amine, poly(9, 9′-di-n-octylfluorene-ran-N, N′-bis(4-n-butylphenyl)-N, N′-diphenyl-1, 4-benzenediamine) (F8-PDA) and poly(9, 9′-di-n-octylfluorene-ran-N, N′-bis(4-t-butylphenyl)-N, N′-diphenyl-9, 10-anthracenediamine) (F8-ADA). On a time scale of nanoseconds, triplet exciton was efficiently formed in F8-PDA through the intersystem crossing (ISC) from singlet exciton with a rate constant of 2.0 × 10⁸ s⁻¹. On the other hand, the ISC was not efficient in F8-ADA, resulting in efficient fluorescence emission. On a time scale of micro- to milliseconds, F8-PDA exhibited bimolecular triplet exciton decay due to triplet–triplet annihilation (TTA), but the TTA was negligible in F8-ADA, indicating that triplet excitons can diffuse freely in F8-PDA while they are trapped at ADA units in F8-ADA. The difference in the ISC efficiency and triplet exciton diffusion is discussed in terms of the aromaticity of the amine units. On the basis of these analyses, we discuss a strategy for further improvement in the efficiency of fluorene–amine copolymer based light-emitting diodes

Photon emission spectroscopy of single oxide-supported Ag-Au alloy clusters

The alloying of Ag and Au has been investigated on the level of individual clusters by analyzing the light emission excited by electron injection from an STM tip. Different Ag-Au alloy and shell-core clusters have been prepared at room temperature on a thin Al2O3 film on NiAl(110) by simultaneous and successive deposition of both noble metals. For simultaneous deposition, one Mie-plasmon resonance has been detected with a wavelength position shifting from the pure Au to the Ag value with increasing Ag content. The results are in agreement with calculations based on Mie theory indicating a complete mixing of both materials. For successive deposition, two Mie resonances have been observed, attributed to plasmon excitations in the shell and core of the clusters. Comparing these results to model calculations, a considerable intermixing of the core and shell materials is concluded, which is especially strong in Au shell-Ag core clusters

Dye sensitization of polymer/fullerene solar cells incorporating bulky phthalocyanines

The light-harvesting efficiency of P3HT:PCBM solar cells can be improved by incorporating near-IR dye molecules such as silicon phthalocyanine derivatives with bulky axial groups (SiPc). In order to study the size effect of the axial groups on the dye sensitization in P3HT:PCBM solar cells, we synthesized five SiPc derivatives with different axial groups: SiPc[OSi(C_{n}H_{2n+1})_{3}]_{2} (SiPcn, n = 2, 3, 4, 6) and SiPc[OSi(iBu)_{2}C_{18}H_{37}]_{2} (SiPcB18). The power conversion efficiency (PCE) increased in the order of n = 2–4, reached the maximum at around n = 4 and 6, and then decreased for SiPcB18 with the longest axial groups. As a result, the PCE was improved to 4.2%, which is larger by 10% than that of P3HT:PCBM control cells without dye molecules. We therefore conclude that the butyl or hexyl chain in the axial ligand is the most appropriate for the dye sensitization in P3HT:PCBM solar cells