Lod Commemorative Coin

Obverse: Front view of a plane, airport buildings, in the background relief of old buildings in the city. Reverse: City coin of Lod, minted at the beginn9ng of the third century CE by Emperor Caracalla, on the coin a head of Tyche (Fortune) looking to the left, she wears a crown representing city-walls and towers.

Wave analysis of sound decay in rectangular rooms

The decay of sound in a rectangular room is analyzed for various boundary conditions on one of its walls. It is shown that the decay of the sound-intensity level is in general nonlinear. But for specific areas and impedances of the material it is possible to obtain a linear initial decay. It is also shown that the coefficients derived from the initial decay rates neither correspond to the predictions of Sabine's or Eyring's geometrical theories nor to the normal coefficients of Morse's wave theory. The dependence of the coefficients on the area of the material is discussed. The influence of the real and the imaginary parts of the specific acoustic impedance of the material on the coefficients is also discussed. Finally, the existence of a linear initial decay corresponding to the decay of a diffuse field in the case of a highly absorbing material partially covering a wall is explained on the basis of modal coupling.

Wave analysis of sound decay in rectangular rooms

The decay of sound in a rectangular room is analyzed for various boundary conditions on one of its walls. It is shown that the decay of the sound-intensity level is in general nonlinear. But for specific areas and impedances of the material it is possible to obtain a linear initial decay. It is also shown that the coefficients derived from the initial decay rates neither correspond to the predictions of Sabine's or Eyring's geometrical theories nor to the normal coefficients of Morse's wave theory. The dependence of the coefficients on the area of the material is discussed. The influence of the real and the imaginary parts of the specific acoustic impedance of the material on the coefficients is also discussed. Finally, the existence of a linear initial decay corresponding to the decay of a diffuse field in the case of a highly absorbing material partially covering a wall is explained on the basis of modal coupling.

Studies on micro explosive driven blast wave propagation in confined domains using NONEL tubes

Explosive driven micro blast waves are generated in the laboratory using NONEL tubes. The explosive mixture coated to the inner walls of the plastic Nonel tube comprises of HMX and Aluminum ( 18mg/m). The detonation is triggered electrically to generate micro blast waves from the open end of the tube. Flow visualization and over pressure measurements have been carried out to understand the propagation dynamics of these micro-blast waves in both confined and unconfined domains. The classical cubic root law used for large scale blast correlation appears to hold good even for these micro-blasts generated in the laboratory.

Polarization switching in radiation damaged ferroelectric crystals

The polarization switching processes in radiation damaged ferroelectrics were studied by the Merz method. In irradiated triglycine sulphate and sodium nitrite, the switching time depends exponentially on the applied electric field. Irradiation increases the importance of nucleation and sideways motion of the domain walls in polarization switching.

Thin-walled timber and FRP-timber veneer composite CEE-sections

This paper compares the structural performance between thin-walled timber and FRP-timber composite Cee-sections. While, thin-walled composite timber structures have been proven to be efficient and ultra-light structural elements, their manufacturing is difficult and labour intensive. Significant effort and time is required to prevent the cracking of the transverse timber veneers, bent in the grain direction, when forming the cross-sectional shape. FRP-timber structures overcome this disadvantage by replacing the transverse veneers with flexible, unidirectional FRP material and only keeping the timber veneers which are bent in their natural rolling direction. The Cee-sections investigated in this study were 210 mm deep × 90 mm wide × 500 mm high and manufactured from five plies. For both section types, the three internal plies were thin (1 mm thick) softwood Hoop pine (Araucaria cunninghamii) veneers, orientated along the section longitudinal axis. The two outer layers, providing bending stiffness to the walls, were Hoop pine veneers (1 mm thick) for the timber sections and glass fibre reinforced plastic (0.73 mm thick) for the FRP-timber sections orientated perpendicular to the inner layers. The manufacturing process is briefly introduced in this paper. The profiles were fitted with strain gauges and tested in compression. Linear Variable Displacement Transducers also recorded the buckling along one flange. The test results are presented and discussed in this paper in regards to their structural behaviour and performance. Results showed that the use of FRP in the sections increases both the elastic local buckling load and section capacity, the latter being increased by about 24 percent. The results indicate that thin-walled FRP-timber can ultimately be used as a sustainable alternative to cold-formed steel profiles.

Tila tilassa : Liturgian ja tilan dialogi alttarin äärellä

This study examines the organisation and transformation of altar space in the modern Evangelical Lutheran Church of Finland in liturgical and architectural perspective. The research data consists of 65 altar spaces in The Finnish Evangelical Lutheran church buildings. All of these were characterised in Church Government records as churches , built 1962 1999 and had been consecrated. The main data was collected by means of observation, photographing, and drawing sketches of altar spaces. The focus of this study concerns the organisation of modern Finnish Evangelical Lutheran altar spaces and, in particular, their changes also in relation to the liturgical movement. The challenge of this approach was especially in discovering the spatial identity of an altar space in terms of unequivocal boundaries. The analysis was realised in three stages. Interiors, the organisation of altar space, as well as architectonic qualities of altar spaces in terms of floor elevations, shapes of ceilings, lighting, and openings in the altar space were analysed. Moreover, attention was focused on furnishing and fixed versus movable pieces of furniture (such as the altar, altar rail, the pulpit, the baptismal font, and lectern). Finally, the potential qualitative and quantitative changes in altar space were examined. All in all, the majority of churches in the data featured elongated church halls with an altar at the end of the nave. To look at the data in chronological perspective, increasingly wide church halls had been built since the 1980s (yet there was only one central hall in which the altar was placed at the middle point of the church). Every third church altar was movable. As for the focal point of this study and the altar in particular, it was my aim to pay attention to the versus populum altar and its development in relation to the (Lutheran) liturgy. Hence, it was meaningful to determine, in terms of interior design, whether liturgists were able to celebrate facing the people attending the service. In the 1960s and 70s, a versus orientem altar featured in more than half of all new Finnish Lutheran churches, yet in 2000 two out of three churches featured a versus populum altar. For architectural and esthetic reasons (and not primarily due to liturgical ideas), also altars standing freely off the walls had been constructed. In terms of the liturgy, versus populum altars had been realised in expectation of increased communication between liturgist and worshippers. However, the analysis indicated that the altar could also become a divider of space. This aspect is a novel finding in relation to earlier and concurrent discussions concerning the liturgical movement. This study concluded, all in all, that altars had been increasingly constructed closer and closer to the worshiping parish and, accordingly, used increasingly often in the versus populum manner. Lecterns were often movable until the millennium this was the case in most altar spaces. Baptismal fonts did not have a permanent place in this data, and the data even included altar spaces with no baptismal fonts in the choir, nor the church hall. The position and status of fonts was generally weakened even if baptism in the Lutheran Church was regarded as one of the two sacraments together with the eucharist. The study concluded that even if baptism is regarded as a sacrament in the church, the position and status of baptismal fonts had weakened overall in newer church architecture. In other words, the tendency of the liturgical movement to emphasise the service and its celebration had obviously had its effect on the placement of baptismal fonts in the church hall. This research indicated that the pieces of furniture that mostly involved (many kinds of) visual and spatial changes included the altar and the lectern. In certain instances, fixed furnishings had been substituted by movable pieces or, moreover, new pieces of furniture and paraphernalia such as music instruments, pieces of art, tables, chairs and plants were brought in. In the Evangelical Lutheran Church of Finland, liturgical changes were principally inspired by the Catholic Church, in which liturgical changes are essentially based on Canon Law. Unlike Finnish Lutheranism, Catholicism provides detailed rules and principles even regarding the design of an altar space. According to this study, in the Finnish Lutheran Church, the primarily functional nature of given guidelines and instructions characterises several practical solutions in furnishing.

Natural convection in rectangular cavities at high Rayleigh number

Natural convection in rectangular two-dimensional cavities with differentially heated side walls is a standard problem in numerical heat transfer. Most of the existing studies has considered the low Ra laminar regime. The general thrust of the present research is to investigate higher Ra flows extending into the unsteady and turbulent regimes where the physics is not fully understood and appropriate models for turbulence are not yet established. In the present study the Boussinesq approximation is being used, but the theoretical background and some preliminary results have been obtained[1] for flows with variable properties.

Laminar and turbulent natural convection in rectangular cavities

A computer program has been developed for the prediction of buoyancy-driven laminar and turbulent flow in rectangular air-filled two-dimensional cavities with differentially heated side walls. Laminar flow predictions for a square cavity and Rayleigh numbers from Ra = 10^3 up to the onset of unsteady flow have been obtained. Accurate solutions for Ra = 5 x 10^6, 10^7, 5 x 10^7 and 10^8 are presented and an estimate for the critical Rayleigh number at which the steady laminar flow becomes unsteady is given for this geometry. Numerical predictions of turbulent flow have been obtained for RaH~0(10^9 -10^11 ) and compared with existing experimental data. A previously developed second moment closure model (Behnia et al. 1987) has been used to model the turbulence. Results indicate that a second moment closure model is capable of predicting the observed flow features.

Laminar and turbulent natural convection in rectangular cavities

"This chapter discusses laminar and turbulent natural convection in rectangular cavities. Natural convection in rectangular two-dimensional cavities has become a standard problem in numerical heat transfer because of its relevance in understanding a number of problems in engineering. Current research identified a number of difficulties with regard to the numerical methods and the turbulence modeling for this class of flows. Obtaining numerical predictions at high Rayleigh numbers proved computationally expensive such that results beyond Ra ∼ 1014 are rarely reported. The chapter discusses a study in which it was found that turbulent computations in square cavities can't be extended beyond Ra ∼ O (1012) despite having developed a code that proved very efficient for the high Ra laminar regime. As the Rayleigh number increased, thin boundary layers began to form next to the vertical walls, and the central region became progressively more stagnant and highly stratified. Results obtained for the high Ra laminar regime were in good agreement with existing studies. Turbulence computations, although of a preliminary nature, indicated that a second moment closure model was capable of predicting the experimentally observed flow features."--Publisher Summary

Neutron-diffraction study of structure and conformation of nucleotide uridine-5 phosphate (disodium salt)

Acta Crystallographica Section A: Foundations of Crystallography covers theoretical and fundamental aspects of the structure of matter. The journal is the prime forum for research in diffraction physics and the theory of crystallographic structure determination by diffraction methods using X-rays, neutrons and electrons. The structures include periodic and aperiodic crystals, and non-periodic disordered materials, and the corresponding Bragg, satellite and diffuse scattering, thermal motion and symmetry aspects. Spatial resolutions range from the subatomic domain in charge-density studies to nanodimensional imperfections such as dislocations and twin walls. The chemistry encompasses metals, alloys, and inorganic, organic and biological materials. Structure prediction and properties such as the theory of phase transformations are also covered.

Recapitulation in generating spatial layouts: Representations of embryogenesis in evolutionary design modelling

The noted 19th century biologist, Ernst Haeckel, put forward the idea that the growth (ontogenesis) of an organism recapitulated the history of its evolutionary development. While this idea is defunct within biology, the idea has been promoted in areas such as education (the idea of an education being the repetition of the civilizations before). In the research presented in this paper, recapitulation is used as a metaphor within computer-aided design as a way of grouping together different generations of spatial layouts. In most CAD programs, a spatial layout is represented as a series of objects (lines, or boundary representations) that stand in as walls. The relationships between spaces are not usually explicitly stated. A representation using Lindenmayer Systems (originally designed for the purpose of modelling plant morphology) is put forward as a way of representing the morphology of a spatial layout. The aim of this research is not just to describe an individual layout, but to find representations that link together lineages of development. This representation can be used in generative design as a way of creating more meaningful layouts which have particular characteristics. The use of genetic operators (mutation and crossover) is also considered, making this representation suitable for use with genetic algorithms.

Mean Flow Measurements in Turbulent Boundary Layers along Mildly Curved Surfaces

An experimental investigation of the mean flow characteristics of two-dimensional turbulent boundary layers over surfaces of mild longitudinal curvature is reported. The study covered both convex and concave walls of \d/Rw I « 0.013 (d being the boundary-layer thickness and Rw being the wall radius). It was found that, whereas the region close to the wall was not affected significantly by wall curvature, the outer region was very sensitive to even mild wall curvature. A detailed study of the wake region using present and other available data suggests a systematic effect of b/Rw on the wake structure. The paper also discusses in detail the effect of mild wall curvature on the boundary-layer development with particular emphasis on the difference in behavior of the boundary layer at short and long distances from the leading edge of the curved wall, an aspect which has not received sufficient attention in previous experimental investigations. An attempt has been made to explain this behavior from a consideration of the structure of turbulence in boundary layers over curved surfaces taken into account.

Time to rest : Signals in shoot apex developmental transitions underlying dormancy

Vuodenajat rytmittävät monivuotisten kasvien elämää pohjoisella pallonpuoliskolla, jolla varmin merkki lähestyvästä talvikaudesta on asteittain lyhenevä päivänpituus. Kun päivänpituus on lyhentynyt tiettyyn raja-arvoon saakka, kasvu hiipuu ja kasvin kehityksessä tapahtuu suuria muutoksia. Väitöskirjatyössäni tutkittiin mekanismeja, jotka liittyvät pituuskasvun päättymiseen, silmujen lepotilan kehittymiseen ja kärkisilmun muodostumiseen hybridihaavan ja koivuntaimilla lyhyen päivänpituuden seurauksena kasvihuoneolosuhteissa. Vain lepotilaiset silmut selviytyvät luonnossa ankaran talvikauden yli, joten etenkin lepotilan kehittymisen tutkiminen on keskeistä pyrittäessä selvittämään monivuotisille kasveille tyypillisen kasvutavan mekanismeja. Jo pitkään on tiedetty, että täysikasvuiset lehdet vastaanottavat tiedon päivänpituudesta ja lähettävät signaaleja varren johtojänteissä ylöspäin kohti kasvin kärkiosaa. Sen sijaan varren kärjen ja kärkikasvupisteen roolia lepotilan kehittymisessä on selvitetty vain vähän. Kuitenkin juuri kärkikasvupisteen selviytyminen vuodesta toiseen on tärkeää, koska sen jakautumiskykyiset solukot tuottavat kasvin maanpäälliset osat. Tässä työssä tehdyissä varttamiskokeissa osoitettiin, että varren kärki ei ainoastaan vastaanota signaaleja lehdistä ja ajoita toimintaansa niiden mukaan, vaan myös kärjellä itsellään on aktiivinen rooli lepotilan kehittymisessä. Erityisesti kiinnitettiin huomiota kärkikasvupisteen eri alueiden, ns. apikaalimeristeemin ja rib-meristeemin erilaisiin tehtäviin ja pääteltiin, että molemmat vaikuttavat lepotilan kehittymiseen. Kokeissa käytettiin normaalien hybridihaapojen lisäksi siirtogeenisiä hybridihaapoja, jotka eivät lopeta kasvuaan lyhyt päivä –olosuhteissa. Siirtogeeniset hybridihaavat ilmensivät voimakkaasti fytokromi A -nimistä valon vastaanottajamolekyyliä rib-meristeemin alueella, mikä saattoi osaltaan vaikuttaa poikkeavaan pituuskasvukäyttäytymiseen. Myös useiden lepotilan kehittymiseen liittyvien geenien ilmenemisessä havaittiin poikkeavuuksia verrattuna ei-siirtogeenisiin kontrolleihin, joiden silmuissa kehittyi lepotila lyhyt päivä –altistuksen seurauksena. Väitöskirjatyössäni havaittiin, että myös kaasumainen kasvihormoni etyleeni toimii viestinvälittäjänä silmujen lepotilan kehittymisessä ja vaikuttaa etenkin lepotilan oikeaan ajoittumiseen. Etyleenillä huomattiin olevan määräävä rooli päätesilmun muodostumisessa: siirtogeeniset koivut, jotka eivät aisti etyleeniä, eivät muodostaneet päätesilmua. Silti siirtogeeniset koivut vaipuivat lepotilaan, joskin myöhemmin kuin ei-siirtogeeniset kontrollit. Tämän perusteella todettiin, että lepotilan ja päätesilmun kehittyminen ovat erillisiä kehitystapahtumia, vaikka ne saattavatkin ajoittua osaksi päällekkäin.

Peroxidases in lignifying xylem of Norway spruce, Scots pine and silver birch

Lignin is a complex plant polymer synthesized through co-operation of multiple intracellular and extracellular enzymes. It is deposited to plant cell walls in cells where additional strength or stiffness are needed, such as in tracheary elements (TEs) in xylem, supporting sclerenchymal tissues and at the sites of wounding. Class III peroxidases (POXs) are secreted plant oxidoreductases with implications in many physiological processes such as the polymerization of lignin and suberin and auxin catabolism. POXs are able to oxidize various substrates in the presence of hydrogen peroxide, including lignin monomers, monolignols, thus enabling the monolignol polymerization to lignin by radical coupling. Trees produce large amounts of lignin in secondary xylem of stems, branches and roots. In this study, POXs of gymnosperm and angiosperm trees were studied in order to find POXs which are able to participate in lignin polymerization in developing secondary xylem i.e. are located at the site of lignin synthesis in tree stems and have the ability to oxidize monolignol substrates. Both in the gymnosperm species, Norway spruce and Scots pine, and in the angiosperm species silver birch the monolignol oxidizing POX activities originating from multiple POX isoforms were present in lignifying secondary xylem in stems during the period of annual growth. Most of the partially purified POXs from Norway spruce and silver birch xylem had highest oxidation rate with coniferyl alcohol, the main monomer in guaiacyl-lignin in conifers. The only exception was the most anionic POX fraction from silver birch, which clearly preferred sinapyl alcohol, the lignin monomer needed in the synthesis of syringyl-guaiacyl lignin in angiosperm trees. Three full-length pox cDNAs px1, px2 and px3 were cloned from the developing xylem of Norway spruce. It was shown that px1 and px2 are expressed in developing tracheids in spruce seedlings, whereas px3 transcripts were not detected suggesting low transcription level in young trees. The amino acid sequences of PX1, PX2 and PX3 were less than 60% identical to each other but showed up to 84% identity to other known POXs. They all begin with predicted N-terminal secretion signal (SS) peptides. PX2 and PX3 contained additional putative vacuolar localization determinants (VSDs) at C-terminus. Transient expression of EGFP-fusions of the SS- and VSD-peptides in tobacco protoplasts showed SS-peptides directed EGFP to secretion in tobacco cells, whereas only the PX2 C-terminal peptide seems to be a functional VSD. According to heterologous expression of px1 in Catharanthus roseus hairy roots, PX1 is a guaicol-oxidizing POX with isoelectric point (pI) approximately 10, similar to monolignol oxidizing POXs in protein extracts from Norway spruce lignifying xylem. Hence, PX1 has characteristics for participation to monolignol dehydrogenation in lignin synthesis, whereas the other two spruce POXs seem to have some other functions. Interesting topics in future include functional characterization of syringyl compound oxidizing POXs and components of POX activity regulation in trees.