Material properties under drawing and extrusion with cyclic torsion

A copper bar was drawn while a lead bar was extruded through a cyclically twisting die in a specifically designed experimental rig. The drawing/extrusion load fluctuated at the same frequency as that of die twisting. The load tended to be at a level of monotonic deformation when the die was changing direction. The degree of the reduction in load for both the drawing and extrusion processes depended on the deformation conditions and requires optimisation for industrial application.

Understanding ring strain and ring flexibility in six - and eight-membered cyclic organometallic group 14 oxides

A simple model was developed for the approximation of ring strain energies of homo- and heterometallic, six- and eight-membered cyclic organometallic group 14 oxides and the degree of puckering of their ring conformations. The conformational energy of a ring is modelled as the sum of its angular strain components. The bending potential energy functions for the various endocyclic M–O–M′ and O–M–O linkages (M, M′=Si, Ge, Sn) were calculated at the B3LYP/(v)TZ level of theory using H3MOM′H3 and H2M(OH)2 as model compounds. For the six-membered rings, the minimum total angular contribution to ring strain, ERSGmin was calculated to decrease in the order: cyclo-(H2SiO)3 (13.0 kJ mol−1)>cyclo-H2Sn(OSiH2)2O (7.0 kJ mol−1)>cyclo-H2Ge(OSiH2)2O (4.9 kJ mol−1)>cyclo-H2Si(OSnH2)2O (3.4 kJ mol−1)>cyclo-(H2SnO)3 (1.7 kJ mol−1)>cyclo-H2Si(OGeH2)2O (0.8 kJ mol−1)≈cyclo-H2Ge(OSnH2)2O (0.7 kJ mol−1)>cyclo-H2Sn(OGeH2)2O (0.1 kJ mol−1)≈cyclo-(H2GeO)3 (0 kJ mol−1). All of the six-membered rings were predicted to adopt (nearly) planar conformations (a=0.996<a<1). By contrast, all eight-membered rings were predicted to adopt strainless, but puckered conformations. The degree of puckering was predicted to increase in the order: cyclo-(H2SiO)4 (a=0.983)<cyclo-H2Sn(OSiH2O)2SiH2 (a=0.959)<cyclo-(H2SiO)2(H2SnO)2 (a=0.942)< cyclo-H2Si(OSnH2O)2SiH2 (a=0.935)<cyclo-(H2SnO)4 (a=0.916)<cyclo-(H2GeO)4 (a=0.885). The differences in ring strain and the degree of puckering were linked to the different electronegativities of Si, Ge and Sn. The results obtained are consistent with experimental ring strain energies; reactivities towards ring opening polymerizations or ring expansion reactions and observed ring conformations of cyclic organometallic group 14 oxides.

Colonial designs: Thomas Karsten and the planning of urban Indonesia

Thomas Karsten (1885 – 1945) is undoubtedly a major figure in the history of architecture and town planning in Indonesia. Between 1915 and 1941 he was involved in town planning in 12 of the 19 municipalities and towns in Java (the most prominent exception being Surabaya) 3 of the 9 towns in Sumatra, and the only town in Borneo This paper does not attempts to investigate or question his importance in this field but to place his architectural and town planning ideas in the context of his broader politico-cultural ideas and activities in the Dutch East Indies between 1914 and 1942, and these, in turn, in the context of an evolving colonialism and colonial discourse.

Research designs and scientific identity in marketing journals: review and evaluation

Purpose - This research is based upon the assumption that the empirical research designs and the scientific identity of a journal are related. The objective is to review and evaluate the empirical research design of papers to determine the scientific identity of a selection of academic marketing journals. Design/methodology/approach – The journal sample consists of the Australasian Marketing Journal (AMJ), the European Journal of Marketing (EJM) and the Journal of Marketing (JM). The review and evaluation considers a six-year period, namely 2000-2005. The content analysis consisted of 811 papers. Findings – The scientific identity of JM may be seen as built upon quantitative research designs and the North American paradigm of research values. The scientific identity of AMJ is based upon a mix of empirical research designs and the Australian paradigm of research values. The scientific identity of EJM is also based upon a mix of empirical research designs, but a multi-continental paradigm of research values. Research limitations/implications – The leading continental journals in marketing maintain a scientific identity based upon the continental paradigm of research values. If it is driven to the extremes, a paradigmatic myopia and inertia of research designs may evolve that limit the scientific identity to be dogmatic and narrow-focused rather than variable and broad-focused. Originality/value – A cross-continental eview and evaluation of research designs and scientific identity of academic marketing journals is presented.

Pituitary adenylate cyclase-activating polypeptide induces translocation of its G-protein-coupled receptor into caveolin-enriched membrane microdomains, leading to enhanced cyclic AMP generation and neurite outgrowth in PC12 cells

Pituitary adenylate cyclase-activating polypeptide (PACAP), a member of the secretin/glucagon/vasoactive intestinal peptide family expressed throughout the nervous system, binds to the PACAP-specific G-protein-coupled receptor family members to promote both neuronal differentiation and survival. Although the PACAP receptor is known to activate its effector protein, adenylate cyclase (AC), and thus enhance cAMP generation, the molecular mechanism utilized by the receptor to activate AC is lacking. Here, we show that PACAP induces neurite outgrowth in PC12 cells by induction of translocation of the PACAP type 1 receptor (PAC1R) into caveolin-enriched Triton X-100-insoluble microdomains, leading to stronger PAC1R-AC interaction and elevated cAMP production. Moreover, we demonstrate that translocation of PAC1R is blocked by various treatments that selectively disrupt caveolae. As a result, intracellular cAMP level is decreased and consequently the PACAP-induced neurite outgrowth retarded. In contrast, addition of exogenous ganglioside GM1 to the cells shows the opposite effects. These results therefore identify the PACAP-induced translocation of its G-protein-coupled receptor into caveolae, where both AC and the regulating G-proteins reside, as the key molecular event in activating AC and inducing cAMP-mediated differentiation of PC12 cells.

Cyclic GMP modulates stomatal opening induced by natriuretic peptides and immunoreactive analogues

In this paper we demonstrate that compounds that promote stomatal opening such as kinetin, atrial natriuretic peptide (ANP) and plant natriuretic peptide immunoanalogues (irPNP) significantly elevate cGMP in guard cell protoplasts. Stomata opened by irPNP are induced to close in the presence of the guanylate cyclase inhibitor, LY 83583. The effect of cGMP on stomatal opening appears to be linked with Ca2+ levels. ANP, irPNP and 8-Br-cGMP all induce stomatal opening and this is inhibited by compounds that lower intracellular Ca2+ levels such as ethylene glycol bis(β-aminoethyl ether) N,N,N’,N’-tetraacetic acid (EGTA), ruthenium red and procaine.

The impact of cell formation on layout designs in cellular manufacturing

This paper provides a procedure to address all three phases of the design for cellular manufacturing namely parts/machines grouping, intra-cell and inter-cell layout designs concurrently. It provides a platform to investigate the impact of the cell formation method on intracell and inter-cell layout designs and vice versa by generating multiple efficient layout designs for different cell partitioning strategies. This approach enables the decision maker to have wider choices with regard to the different number of cells and to assess various criteria such as travelling cost, duplication of machines, space requirement against each alternative. The performance of the model is demonstrated by applying it to an example selected from literature.

Constitutive modelling of drawing and extrusion with cyclic torsion

In the current work, constitutive models are developed to describe the cyclic hardening and softening led by the strain path chaneg.  The contribution of deformation conditions such as drawing and extrusion speed, cyclic rotating angle on the drawing and extrusion force will be investigated.  The development of such constitutive models will provide insight into the optimization of operation conditions to explore the potential of industrial applications.