Compressive stresses of mould mixture

The source of compressive stresses lies in the structure of quartz sand. By reaching the critical temperature (from 560 to 580 °C), the quartz sand grains increase volume. The increase in volume causes the movement of surrounding grains of sand. In this paper, it is shown by the dilatometric investigations of different granulometric compositions of quartz sands how the granulometric composition affects the size of the mould dilatation caused by heating during pouring of the melt

Multinational and Indigenous IT Companies in Ireland: Exploring the Spatial Relationships between the Two Tiers

Information Technology (IT) multinational enterprises (MNEs) have garnered a significant amount of attention in relation to the growth of indigenous IT sectors (Brannigan and McManus, 2014; Siedschlag, Zhang and Smith, 2013; van Oort and Atzema, 2004). Compared to some sectors, the IT industry - which trades in immaterial goods - may be less dependent on spatial constraints since it does not rely on large scale labor force or massive movement of raw materials. This alleged ‘death of distance’ promises great changes in international business and poses questions about how indigenous economies and spatial policy are being affected (Maeng and Nedovic-Budic 2008 and 2010). Even though in principle international business is open to organizations of any size, in practice it tends to be dominated by MNEs. MNEs can sustain the cost and capacity of operating across countries and to address the volatility of functioning across diverse jurisdictions. Still, MNEs do not exist in a solely stateless space. They need to ‘touch the ground’ in specific places to hire people and get work done, to set headquarters and formalize legal bounds. They also play an important role in the formation of industrial clusters and networks (Nadvi, 1995) From the perspective of local host economies, attracting an MNE is perceived as a means of stimulating the growth of indigenous companies through knowledge spillovers (Motohashi and Yuan, 2010; Breznitz, 2010). Often, a question for governments is if the presence of MNEs within their territory benefits the indigenous economy and if there is a satisfactory number of new firms emerging from the purported knowledge and capital spill-overs. This is especially the case for IT as there are lower barriers to accessing means of production for entry into the market (Benkler: 2006), resulting in a higher potential for small businesses to start and grow. The objective of policy makers in attracting MNEs is not only job creation via MNEs, but job and wealth creation via the emergence of new indigenous IT companies and the strengthening of existing indigenous companies, through transfer of knowledge and other forms of capital from MNEs. The policy process is also focused on encouraging regional innovation systems which comprise of both international and indigenous companies, and ultimately helps build a national innovation system (Chung, 2002). Against this broad background, the presented research focuses on networks of inter-organizational relations (rather than the classic dichotomy hierarchy vs. market), which are approached through a spatial analysis of clusters. More precisely, it focuses on the spatial dimension of their interactions and the nature of their communications. While we recognize the complexity of these phenomena, with this research we aim at a concrete contribution to the debate on clustering and proximity as locational factors (among others: Mole et al.: 2011)

The effect of particulate matter on paper degradation

Background: In this work we explore the chemical effects of particulate matter on paper. We exposed paper made of pure cellulose to the environment in different locations in central London, outdoors (in sheltered conditions) and indoors, for a period of up to 6 months. We monitored particulate matter (PM) deposition by counting the particles deposited every month with a scanning electron microscope. We analysed elemental composition of the deposited particles using inductively coupled plasma mass spectrometry. After accelerated degradation of the exposed samples, we determined the degree of polymerisation using viscometry. Results: We observed higher deposition rates and higher metal concentration outdoors than indoors. Elemental analysis of the deposited particles revealed the presence of some transition metals (Fe, Cu, Cr) that can contribute to the degradation of cellulose fibres through the Fenton reaction. By comparing the degree of polymerisation of pro‑ tected, unprotected and unexposed samples we could determine the relative contribution of PM deposition on the increase of the degradation rate. We found that the surface concentration of iron correlates with the reduction in the degree of polymerisation of the exposed paper. Conclusions: The results suggest that the presence of Fenton metals in PM has a significant effect on the accelera‑ tion of the degradation of cellulose. However, we estimate that this will unlikely occur at the levels of area coverage by PM that are typically avoided in indoor heritage through preventive maintenance and cleaning

System and method for maximizing throughput in a telecommunications system

Provided is a system and method for maximizing throughput in a telecommunications network. The method is operable to select and service a request for a communication session by selecting a bit rate and assigning the bit rate to the request. The method selects the request from a pool of queued requests and the bit rate from all supported bit rates. The request and bit rate are selected based on calculations that determine an amount of power needed for each queued request at each bit rate. The calculations result in ratios representing each combination of power and bit rate for each request. The method selects the ratio having the highest number of bit rates per power unit and assigns the bit rate to the associated request. This approach enables the method to select a queued request according to current network constraints and so provides an optimal approach that maximizes throughput

Influence of process parameters on castability at full mold casting

This paper examines the effect of the temperature of pouring the melt, the density of the model of foamed polystyrene and the casting with or without a vent on castability. The testing was carried out in accordance with the experiment plan 23 i.e. during testing the value of the parameters of influence was changed at two levels: the melt pouring temperature of 640 °C and 600 °C, casting with or without a vent, and the density of foamed polystyrene model of 15 kg/m3 and 30 kg/m3

Global Foliations of Vacuum Spacetimes with T2T^2 Isometry

We prove a global existence theorem (with respect to a geometrically- defined time) for globally hyperbolic solutions of the vacuum Einstein equations which admit a $T^2$ isometry group with two-dimensional spacelike orbits, acting on $T^3$ spacelike surfaces.Comment: 38 pages, 0 figures, LaTe

Cosmological spacetimes not covered by a constant mean curvature slicing

We show that there exist maximal globally hyperbolic solutions of the Einstein-dust equations which admit a constant mean curvature Cauchy surface, but are not covered by a constant mean curvature foliation.Comment: 11 page

On completeness of orbits of Killing vector fields

A Theorem is proved which reduces the problem of completeness of orbits of Killing vector fields in maximal globally hyperbolic, say vacuum, space--times to some properties of the orbits near the Cauchy surface. In particular it is shown that all Killing orbits are complete in maximal developements of asymptotically flat Cauchy data, or of Cauchy data prescribed on a compact manifold. This result gives a significant strengthening of the uniqueness theorems for black holes.Comment: 16 pages, Latex, preprint NSF-ITP-93-4