Particle Size Distribution and Human Respiratory Deposition of Trace Metals in Indoor Work Environments

Respiratory response to inhalation of fine particles has been investigated for the aerosol generated by welding. Particles were sampled using a pair of 5-stage cascade impactors operating at 1 l./min flow rate. The subject exhaled into one impactor through an air ballast arrangement, and the other impactor simultaneously sampled the surrounding air. Particle size fractions were analyzed for principal elemental constituents from sulphur to lead using proton induced X-ray emission, PIXE. The results indicated a complex respiratory response, including both increase in particle size due to exposure to high humidity in the respiratory tract and deposition of particles during inhalation. The response was found to be different for the element group Mn, Cr, Fe, Ni compared to the group K, Ca, Ti by observing the associations among the elements as a function of particle size in the inhaled and exhaled aerosol. However, for respiratory deposition efficiency alone in all runs averaged together, no systematic differences between the different elements are demonstrated at the 99 % confidence level

A global clean cooking fuel initiative

This article calls for engaging the public and private sectors of developing and industrialized countries in a global clean cooking fuel initiative (GCCFI) to bring about a worldwide shift to clean fluid fuels for cooking and heating in 10-15 years' time - with an emphasis on providing clean fuel to the poorest households. This initiative is crucial to implementation of the Millennium Development Goals and the Plan of Implementation of the World Summit on Sustainable Development. The article builds on (1) analyses in this special issue of Energy for Sustainable Development of challenges to sustainable development posed by use of solid fuels for cooking and water heating (and for space heating in temperate climates) and opportunities for addressing them by bringing about a shift to clean fluid fuels, and (2) an extensive and compelling literature on the problems posed by this reliance on solid fuels

Energy efficiency from the perspective of developing countries

Energy efficiency improvements are particularly important for developing countries. In most developing countries, the costs of reducing energy use by one kWh with more efficient technology are invariably much lower than the costs of increasing energy supply by one kWh through investments in new energy supply equipment. In fact, if the unit cost of energy supply increases is taken as the reference for comparison, then the relative costs of energy-efficient technologies can turn out to be negative. Thus, capital can be saved by investing in energy efficiency compared to investing in energy supply. Energy needs in the South are different from those of the North because of differences in climate (e.g., space heating is not required in most of the South) and because satisfaction of basic human needs and infrastructure building must be given paramount attention in the South. Consequently, the innovations necessary are also different. For example, innovations in the processing of basic materials (e.g., steel, cement, glass, etc.) are needed in developing countries because these materials are needed for infrastructure-building. Yet innovations in the basic materials-processing industries will come only slowly from the industrialized countries because the infrastructure-building era is largely over there and the demand for basic materials is largely saturated. Because such industries are energy-intensive, innovations would result in less energy-intensive, less costly and cleaner technologies with beneficial implications for energy futures in developing countries. Such opportunities for technological leapfrogging should be identified and utilized. The technical and economic potential for energy saving is 20–50% in the case of efficiency improvements in existing installations and 50–90% in the case of new installations. The potential for further efficiency improvements through continued research and development is large because fundamental physical constraints on efficiency are remote. The pursuit of energy efficiency improvement should be carried out in parallel with improvements in institutions, entrepreneurship management and human resource development. A key policy is to bring more energy-efficient technologies to the market, and to focus market attention on energy efficiency performance. Several successful approaches have been tried. The incentive structures in the markets are fundamental, as illustrated by integrated resource planning and utility demand side management that took off in the US only after the regulations of the power industry were changed to make it possible for utilities to earn profits on demand side energy efficiency investments. There is a need for an integrated view of the concept and role of energy efficiency revealing its structure and interconnections. Energy efficiency should be an integral characteristic of any product or activity. Emphasis on energy efficiency would liberate resources that can then be used for socio-economic development

The 2008 evaluation of SYKE

Riippumaton kuusijäseninen kansainvälinen asiantuntijapaneeli arvioi SYKEn tutkimustoimintaa ja asiantuntija-palveluita marraskuussa 2008. Työssään se hyödynsi saamiansa taustamateriaaleja ja tekemiänsä kysely- ja haastatteluaineistoja. Arviointipaneelin mukaan SYKE on aktiivinen ja elinvoimainen laitos. SYKEn menetelmälliset vahvuudet ovat laitoksen kehittämissä tieteellisissä lähestymistavoissa ja työkaluissa, jotka pohjautuvat sen laajoihin ympäristötietovarantoihin. Panelistien keskeisimmät suositukset liittyvät tutkimuksen ja asiantuntijapalveluiden organisatoriseen jakoon, operatiivisiin 24/7-palveluihin, neuvottelukunnan rooliin sekä SYKEn rooliin ja asemaan ympäristönsuojelun kentässä, erityisesti ympäristöpolitiikan tukemisessa. Panelistien näkemysten mukaan SYKEllä on hyvät mahdollisuudet vahvistaa ennakoivaa roolia monessa: arvioida ympäristöpolitiikan toteutumista, kehittää kestävän kehityksen strategioita ja skenaarioita sekä tuottaa tietoa eri politiikkavaihtoehtojen ympäristövaikutuksista. Panelistit suosittelevat tutkimuksen ja politiikan välisen yhteyden vahvistamista luomalla osallistumiseen ja kokonaisvaltaiseen arviointiin perustuva lähestymistapa, jossa hyödynnetään SYKEn ympäristöosaamista ja sidosryhmien tarpeita. SYKEn ympäristöön liittyvät paikkatiedot ja sosio-ekonomiset tiedot mahdollistavat yhdessä innovatiivisten yhdennettyjen arviointien tekemisen. Panelistien näkemyksen mukaan tavoite lisätä SYKEn yhteistyötä kansallisten ja kansainvälisten yliopistojen kanssa, ympäristö ja luonnonvarat -konsortion perustaminen sekä osallistuminen strategisen huippuosaamisen keskittymien ohjelmiin ovat kaikki tärkeitä SYKEn kehittymisen kannalta

A meshless method for an inverse two-phase one-dimensional nonlinear Stefan problem

We extend a meshless method of fundamental solutions recently proposed by the authors for the one-dimensional two-phase inverse linear Stefan problem, to the nonlinear case. In this latter situation the free surface is also considered unknown which is more realistic from the practical point of view. Building on the earlier work, the solution is approximated in each phase by a linear combination of fundamental solutions to the heat equation. The implementation and analysis are more complicated in the present situation since one needs to deal with a nonlinear minimization problem to identify the free surface. Furthermore, the inverse problem is ill-posed since small errors in the input measured data can cause large deviations in the desired solution. Therefore, regularization needs to be incorporated in the objective function which is minimized in order to obtain a stable solution. Numerical results are presented and discussed

The two phases of core formation : orbital evolution in the centres of ellipticals with supermassive black hole binaries

The flat stellar density cores of massive elliptical galaxies form rapidly due to sinking supermassive black holes (SMBHs) in gas-poor galaxy mergers. After the SMBHs form a bound binary, gravitational slingshot interactions with nearby stars drive the core regions towards a tangentially biased stellar velocity distribution. We use collisionless galaxy merger simulations with accurate collisional orbit integration around the central SMBHs to demonstrate that the removal of stars from the centre by slingshot kicks accounts for the entire change in velocity anisotropy. The rate of strong (unbinding) kicks is constant over several hundred Myr at similar to 3 M-circle dot yr(-1) for our most massive SMBII binary (M-BH = 1.7 x 10(10) M-circle dot). Using a frequency-based orbit classification scheme (box, x-tube, z-tube, rosette), we demonstrate that slingshot kicks mostly affect box orbits with small pericentre distances, leading to a velocity anisotropy of beta less than or similar to -0.6 within several hundred Myr as observed in massive ellipticals with large cores. We show how different SMBH masses affect the orbital structure of the merger remnants and present a kinematic tomography connecting orbit families to integral field kinematic features. Our direct orbit classification agrees remarkably well with a modern triaxial Schwarzschild analysis applied to simulated mock kinematic maps.Peer reviewe

A System-Performance-Based Comparison of Sparse Regular and Irregular Antenna Arrays for Millimeter-Wave Multi-User MIMO Base Stations

A system-level study was conducted that evaluated the system performance of various dense and sparse antenna array configurations for application in millimeter-wave multi-user multiple-input multiple-output base stations. The performance was evaluated by investigating the probability that a user experiences an outage when a zero-forcing pre-coder is used in a random line of sight scenario. This paper shows that the outage probability significantly decreased when irregular sparse arrays were used rather than regular sparse or regular dense arrays. A re-configurable linear array was designed and realized as a demonstrator. It used 3D-printed aluminum box horn antenna elements that had wide scanning range in the azimuthal plane and a small scanning range in the elevation plane. For the demonstrator, it was shown that the outage probability was reduced from 3.85% to 0.64% by moving from a sparse regularly spaced array to a sparse randomly spaced array. This amounted to an improvement of a factor of six. The sparse topology allowed for the usage of large antenna elements that had an increased gain and still achieved wide-angle scanning, while reducing mutual coupling to a minimum