Electric cars are as unpopular as ever, but the hopes for environmentally sound, quiet vehicles may lie, surprisingly, with the commercial market. Advances in electric vans and lorries are reviewed. (author).
An overview is given of several computer models in use in the Netherlands to determine and analyze the quality of air and the effect of air pollution abatement measures. [Dutch] Voor het vaststellen van de luchtkwaliteit of het bepalen van het effect van emissiereducerende maatregelen op die luchtkwaliteit zijn in ons land meerdere computermodellen beschikbaar. In het kader van het Vooronderzoek Innovatieprogramma Luchtkwaliteit (VIPL) wilde het ministerie van Verkeer en Waterstaat meer inzicht in de betrouwbaarheid en specifieke eigenschappen van deze modellen. Deze studie geeft daarom een overzicht en analyse van de verschillen, overeenkomsten en voor- en nadelen van de meest gangbare Nederlandse computermodellen om de luchtkwaliteit rond snelwegen te bepalen. Dit zijn: Het Voorspellingssysteem Luchtkwaliteit Wegtraces ...
The Construction of a natural gas-fired combined heat and power plant at the site of the Pernis refinery will further reduce the emission of SO2 and NOx. [mk]. [Dutch] Met de bouw van een aardgasgestookte warmte/kracht-installatie op het terrein van de raffinaderij Pernis wordt de emissie van SO2 en NOx verder gereduceerd.
As a result of a lower value of the energy efficiency coefficient (EPC) for houses and the implementation of the Energy Performance Building Directive (EPBD), both in 2006, the interest in applying renewable energy systems is growing. Therefore, this issue is dedicated to renewable energy and related energy systems. [Dutch] Het begrip 'duurzaam' is van toepassing op twee pijlers: een pijler betreft het gebruik van duurzame materialen, de tweede pijler is duurzame energie. Door verlaging van de Energieprestatiecoefficient (EPC) voor woningen per 2006 en de invoering van de Europese richtlijn Energy Performance Building Directive (EPBD) in 2006, krijgt duurzame energie een nieuwe impuls. Reden voor de redactie van ThemaTech om deze aflevering te wijden aan duurzame energie en verwante ystemen.
Oct 30, 2006 ... Pigment Analysis by HPLC at Horn Point Laboratory. Laurie Van Heukelem. Crystal Thomas. Meg Maddox. University of Maryland Center for ...
... CVn) consisting of a dM3 star and a cool white dwarf that must have evolved through the common-envelope stage of binary star evolution (Else van ...
There's nothing that prevents us from being vigilant. In fact, freedom requires vigilance, and certainly our security in today's world requires vigilance. But one of the...
Secondary ischemic necrosis of femoral head due to loss of blood supply following to femoral neck fracture is well known. The regional distribution of bone-seeking radiopharmaceuricals in the skeleton can depend on a number of factors, but bone blood flow is a major physiological determinant of regional skeletal uptake of Tc-99m polyphosphate and bone imaging may thus be used for the evaluation of vascularity of the femoral head. The authors made a comparative study of scintigraphic findings and operative findings of 28 cases of femoral neck fracture treated at Kyung Hee University Hospital from April 1980 to May 1984. The results were as follows: 1. In 16 cases of proven avascular necorsis of femoral head, scintigraphy showed absent or decreased activity in 14 cases (87.5%), while radiography showed increased density in 10 cases (62.5%). 2. In 12 cases of proven vital femoral head, scintigraphy showed increased activity in 9 cases (75%) and radiography showed ...
The main conclusion of the study on the title subject is that the impacts of climatic change in the Netherlands are still limited. However, the impacts will be stronger in the next decades and will be even problematic at the end of this century. In this book an overview is given of probable changes in the climate for the Netherlands, danger for flooding in specific areas of the Netherlands, changes of the nature, impacts for agriculture, tourism and recreation, and industry and businesses, and risks for public health. [Dutch] De effecten van klimaatverandering in Nederland zijn nu nog beperkt. Ze zullen echter de komende decennia toenemen, maar pas tegen het eind van deze eeuw problematisch worden. Dat is de hoofdboodschap van de titelstudie. De studie is opgesteld in samenwerking met een reeks instellingen, die zijn verenigd in het Platform Communicatie Klimaatverandering (PCCC). Het klimaat verandert: de zeespiegel ...
This report focuses on the question whether a further increase in environmental taxes can contribute to achieving a sustainable economy in which depletion and climate risks should be reduced to an acceptable level for 2050. The strategy to achieve this consists of four main elements: (1) Introduction of a new CO2 tax as part of the Energy Tax; (2) Broadening of the Energy Tax to sectors such as agriculture and industry and the cancellation of subsidies and tax rebates; (3) Expansion of new tax bases for import / production of natural resources (wood, fish, meat) and space; and (4) European agenda on 'greening'. [Dutch] In dit rapport staat de vraag centraal of een verdere groei van milieubelastingen een bijdrage kan leveren aan het realiseren van een duurzame economie waarin klimaat- en uitputtingsrisico's tot een aanvaardbaar niveau moeten zijn teruggebracht voor 2050. De strategie om dit te bereiken bestaat uit vier ...
The Netherlands Chemical Industry Association (VNCI) is investigating the potential for expansion of the CHP capacity in the Dutch chemical industry. This report discusses the return on investment for CHP installations and the market conditions. Moreover, scenario results are presented for the CHP potential and the development of CHP in the chemical industry until 2020. [Dutch] De Vereniging van de Nederlandse Chemische Industrie (VNCI) heeft onderzoek laten uitvoeren om vast te stellen welke economische en beleidsmatige voorwaarden er zijn om het WKK-potentieel in de Nederlandse chemie te realiseren. Dit rapport brengt de marktpositie van WKK en de rentabiliteit van investeringen in WKK in beeld. Verder worden resultaten gegeven voor de potentiele energiebesparing en emissiereductie en wordt een scenario gepresenteerd voor het WKK-potentieel in de chemische industrie tot 2020.
In this work, a powerful analytical method, called He's parameter-expanding methods (HPEM) is used to obtain the exact solutions of non-linear modified Van der Pol's oscillator. The classical Van der Pol equation with delayed feedback and a modified equation where a delayed term provides the damping are considered. It is shown that one term in series expansions is sufficient to obtain a highly accurate solution, which is valid for the whole solution domain. Comparison of the obtained solution with those obtained using perturbation method shows that this method is effective and convenient to solve this problem. This method introduces a capable tool to solve this kind of non-linear problems.
A lower energy efficiency standard for buildings (EPC) can have a negative impact on thermal comfort and indoor air quality. Cooperation and integrated design are preconditions for a correct use, installation and maintenance of heating and ventilation systems in buildings. [Dutch] Er komt steeds meer kritiek op de wijze waarop in ons land woningen en gebouwen worden gebouwd. Op dit moment is het vooral woonhuisventilatie waar veel om te doen is. Van beleidsmakers tot aannemers en van Consumentenbond tot gezondheidsdiensten; iedereen vraagt zich af of we met vergaande isolatie onze woningen en gebouwen nog wel leefbaar houden. In dit artikel wordt een pleidooi gehouden voor onderlinge samenwerking en integraal ontwerp als randvoorwaarden voor een goede toepassing, installatie en onderhoud van verwarmings- en ventilatiesystemen in gebouwen.
Robert van Gulik was a respected Dutch sinologist and author who first translated a collection of traditional Chinese detective stories into English and then created additional fictional stories based...Full Text Available
This section of the report is concerned with the study of the metallisation, oxidation and doping of materials which are of importance to the micro-electronics industry. The Van de Graaff accelerator and radioactive tracers are used for studying surface and sub-surface behaviour of these materials.
The results of a comprehensive infrared imaging search for the putative 0.06 M{sub {circle_dot}} astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 {micro}m reveal a diffraction limited core of 0.09 inch and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50 M{sub J} brown dwarf would be only 1 magnitude fainter than van Maanen 2 at this wavelength and the astrometric analysis suggested a separation of 0.2 inch. In the case of a chance alignment along the line of sight, a 0.4 mag excess should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published ISO observations of van Maanen 2 at 6.8 {micro}m and 15.0 {micro}m which are consistent with photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with T{sub eff} ...
Recently, G. C. Van Orden, J. G. Holden, and M. T. Turvey (2003) proposed to abandon the conventional framework of cognitive psychology in favor of the...Full Text Available
A procedure has been developed for judging one-pile foundations for wind turbines. It appears that these foundations are good alternatives for block foundations. It is recommended to develop a program for testing one-pile foundations and to carry out a further research into their dynamic behavior.
This purpose of this paper is to describe the optimizing Peripherally Inserted Central Catheter (PICC) insertion, revising data collection strategies, estimating workloads, and calculating the financial savings generated by the vascular access nurse (VAN)...
PCR was used with the primer pair VANS1-NS21 to detect the arbuscular mycorrhizal fungus Glomus intraradices (commercial inoculum source) on roots of lettuce, zinnia, leek, pepper, and endive plants....Full Text Available
An overview is given of the interest of the Dutch government, several organizations and consumers in the quality of the indoor environment. Main aspects, sub-aspects and indicators for the indoor environment of dwellings are listed: site selection, thermal comfort, air quality, light, view, privacy, noise, safety, and radiation. [Dutch] In het veld wordt onvoldoende aandacht en prioriteit gegeven aan de kwaliteit van het binnenmilieu. Het ligt voor de hand de kennis over de relatie gezondheid en binnenmilieu bij professionele partijen te vergroten. In dit kader is het Binnenmilieuprofiel voor de kantooromgeving geintroduceerd. Aan de hand hiervan kan de discussie worden gevoerd tussen vrager en aanbieder over de kwaliteit van het binnenmilieu. Het zou de basis kunnen zijn voor een keurmerk Gezond Gebouw. Dezelide binnenmilieuproblematiek doet zich natuurlijk ook voor bij woningen. In dit artikel wordt een introductie gegeven ...
This report gives an overview of Dutch R&D efforts in the field of energy supply. For a wide range of energy carriers and groups of technologies information is gathered on a number of aspects: the current status of relevant technologies, the current and potential application in the Netherlands, the governmental budget and the non-governmental budget for R&D, the parties involved in R&D, the main R&D topics, and environmental and societal aspects of application. 3 tabs., 98 refs.
The school building complex Waterland in The Hague, Netherlands, was built with a hybrid ventilation system. The indoor environment and energy consumption were monitored for one year. Air quality and thermal comfort are of a high quality and the consumption of energy for heating is circa 35% lower than normal. The Waterland project was one of eight demonstration projects, carried out within the framework of the ECBS-Annex 35: Hybrid ventilation in New and retrofitted Office Buildings. ECBS stands for the IEA-program Energy Conservation in Buildings and Community Systems. [Dutch] In ECBCs-annex 35 (ECBS staat voor het IEA-programma Energy Conservation in Buildings and Community Systems) is uitgebreid onderzoek gedaan naar hybride ventilatiesystemen in kantoren en scholen. Dit project heeft geleid tot acht internationale voorbeeldprojecten, waarvan scholencomplex Waterland te Den Haag er een van is. Het scholencomplex is in 2003 opgeleverd met een hybride ...
At the Huizhou oil field in China the FPSO Munin of Bluewater completely relies on five computer controlled propulsion screws to position itself, a so-called Dynamic Positioning (DP) system. In this article report is given of training given to the crew of the FPSO Munin. A floating production, storage and offloading (FPSO) unit is a floating vessel used by the offshore industry for the processing and storage of oil and gas. [Dutch] Op het Huizhou oileveld in China vertrouwt de FPSO (floating production, storage and offloading unit) Munin van Bluewater uitsluitend op een vijftal computergestuurde voorstuwingsschroeven om zichzelf in positie te houden, een zogenaamd Dynamisch Positionering (DP) systeem. In dit artikel wordt verslag gedaan van en uitleg gegeven over trainingen die zijn gegeven aan de bemanning van de FPSO Munin.
A brief overview is given of the developments with regard to the ease of operation of water heaters in houses, in particular the option to use remote control (e.g. the telephone) to adjust the temperature. [Dutch] Woonkwaliteit betekent voor de meeste mensen een combinatie van luxe, comfort en gemak. Vertaald naar ons vakgebied, houdt dat onder andere in: luxe badkamers met bijvoorbeeld massagedouches, waarvoor grote volumestromen warmtapwater benodigd zijn, een comfortabel binnenklimaat en een stuk bedieningsgemak om een en ander te realiseren. Nu is Nederland een uitgesproken combiketel land, waarbij de ketel over het algemeen met behulp van eenvoudige (klok)thermostaten wordt geregeld. Onze Oosterburen kiezen veel vaker voor separate ketel-boilercombinaties voor een groot warmtapwater comfort en uitgebreide regelapparatuur voor de (ruimte)temperatuurregeling. Maar ook in Nederland neernt de vraag naar meer warmwater toe en worden steeds ...
A conceptual design of an advanced sodium/sulfur cell for US electric-van applications has been completed. The important design factors included specific physical and electrical requirements, service life, manufacturability, thermal management, and safety. The capacity of this cell is approximately the same as that for the ``PB`` cell being developed by Silent Power Limited (10 Ah). The new cell offers a 50% improvement in energy capacity and nearly a 100% improvement in peak power over the existing PB cells. A battery constructed with such cells would significantly exceed the USABC`s mid-term performance specifications. In addition, a similar cell and battery design effort was completed for an advanced passenger car application. A battery using the van cell would have nearly 3 times the energy compared to lead-acid batteries, yet weigh 40% less; a present-day battery using a cell specifically designed for this car would provide 50% more energy ...
In the first part of the nineties many office buildings were equipped with indoor climate installations which do not meet present standards. Several options are available to improve such installations for ventilation capacity, cooling capacity, thermal comfort and air quality. One of the options concern the installation of an air conditioner in combination with heat recovery. In this article attention is paid to the renovation of the air conditioning system in the Printer house, an office building in Zwolle, Netherlands. [Dutch] Begin jaren negentig zijn veel kantoorpanden gebouwd waarvan de klimaatinstallatie tegenwoordig niet meer voldoet. De ventilatiecapaciteit is ontoereikend en koeling is mondjesmaat aanwezig, of slechts als topkoeling. Het comfort en de luchtkwaliteit zijn dan ook onder de maat. Er zijn verschillende mogelijkheden om dit te verbeteren. Plaatsing van een nieuwe luchtbehandelingskast met warmteterugwinning is daar een van. ...
This action plan describes the view of the Working Group Decentralized Infrastructure on how grid operators should prepare for the implementation of decentralized applications in the next 4 years. Currently, various parties (among which grid operators) are making preparations for the installation of smart meters in dwellings in the Netherlands. The operation will take up several years. The working group sketches opportunities with the smart meter cupboard and the smart meter in support of the developments under the Energy Transition (ET), identifying several actions in this action plan (Chapter 3). In 2007, the working group set up 'position papers' for the twelve transition paths and ET working groups, anticipating developments for the decentralized infrastructure. From the viewpoint of the grid operator, the working group offers actions that may contribute to realizing a sustainable energy system (Chapter 11). Chapter 12 provides all action items in one ...
We report de Haas--van Alphen measurements of the Fermi surface of lutetium at temperatures down to 0.3 K and in fields up to 150 kG in the (1010) and (1120) planes. Lutetium, having a filled 4f shell, serves as a nonmagnetic prototype of the structurally similar (hcp), trivalent, heavy rare-earth elements from Gd to Tm. The fact that no complete frequency branches were observed indicates that there are no closed pieces of the Fermi surface. We observed all but one orbit predicted by relativistic augmented-plane-wave calculations of Keeton and Loucks and by recent spin-orbit--linearized-augmented-plane-wave calculations of Tibbetts and Harmon. The data support a geometry similar to that of yttrium, and in good qualitative agreement with energy-band theory.
The most important aim of the title program is to investigate the possibility to convert long-lived actinides and mobile fission products in short-lived and stable isotopes by means of nuclear transmutation and recycling. First, an overview is given of the present situation regarding fission material waste, the origin of such waste in light water reactors and the options for interim and ultimate storage. Next, attention is paid to the aim of the the RAS program, the working method and the results so far of national and international research on the transmutation of actinides and fission products. Speculative expectations for the future are briefly outlined. The report also contains four appendices with technical aspects of the title subject: the RAS program of ECN, chemical aspects of reprocessing fission material, transmutation in fission reactors and in accelerators. 12 figs., 7 tabs., 4 appendices, 57 refs.
Monopolar charge disorder effects are studied in the context of fluctuation-induced interactions between neutral dielectric slabs. It is shown that quenched bulk charge disorder gives rise to an additive contribution to the net interaction force which decays as the inverse distance between dielectric surfaces. This effect may thus completely mask the standard Casimir--van der Waals effect. By contrast, annealed (bulk or surface) charge disorder leads to a net interaction force whose large-distance behavior coincides with the universal Casimir force between perfect conductors, which scales as inverse cubic distance, and the dielectric properties enter only in subleading corrections.
By means of an analogous simulator, which can simulate a power supply system, a method to determine the transfer function of a Power System Stabilizer (PSS) is developed. The purpose of the PSS is to damp unwanted electro-mechanical oscillations. The method is very systematic and there is no need for specified values of the parameters used in the system. It is assumed that the power generator system is linear for small variations. The system can be considered to be a black box. Measurements executed by means of this method are completely controlled by the person who enforces the measurement. By applying this method carefully, irregularities are almost out of the question. The equipment necessary are a PC with two AD-ports and an adjustable sinus-generator. A comparison is made with a more traditional method, in which a spectrum analyzer is used. 4 figs., 7 refs.
The Electric Fuel Limited (EFL) refuelable zinc-air battery system is currently being tested in a number of electric vehicle demonstration projects, the largest of which is a field test of zinc-air postal vans sponsored chiefly by Deutsche Post AG (the German Post Office). The zinc-air battery is not recharged electrically, but rather is refueled through a series of mechanical and electrochemical steps that will require a special infrastructure in commercial application. As part of the German Post Office field test program, Electric Fuel designed and constructed a pilot zinc anode regeneration plant in Bremen, Germany. This plant is capable of servicing up to 100 commercial vans per week, which is adequate for the field test vehicle fleet. This paper will describe the design and operation of each of the areas and devices within the plant.
Several studies on individual control of the thermal indoor climate and indoor air quality are discussed. A distinction is made between the effect on health, the effect on comfort and the effect on performance. The underlying mechanisms are examined more closely, and concrete recommendations are made for future design norms. [Dutch] Een aantal studies op het gebied van beinvloeding van thermisch binnenklimaat en binnenluchtkwaliteit wordt besproken. Hierbij wordt onderscheid gemaakt tussen invloed op gezondheid, comfort en prestaties. Vervolgens wordt dieper ingegaan op achterliggende mechanismen en worden concrete aanbevelingen gedaan voor toekomstige ontwerpen.
To represent a heterogeneous unsaturated fractured rock by its homogeneous equivalent, Monte Carlo simulations are used to obtain upscaled (effective) flow properties. In this study, we present a numerical procedure for upscaling the van Genuchten parameters of unsaturated fractured rocks by conducting Monte Carlo simulations of the unsaturated flow in a domain under gravity-dominated regime. The simulation domain can be chosen as the scale of block size in the field-scale modeling. The effective conductivity is computed from the steady-state flux at the lower boundary and plotted as a function of the averaging pressure head or saturation over the domain. The scatter plot is then fitted using van Genuchten model and three parameters, i.e., the saturated conductivity K{sub s}, the air-entry parameter {alpha}, the pore-size distribution parameter n, corresponding to this model are considered as the effective K{sub s}, effective {alpha}, and ...
Availability of a natural gas-powered van that meets California`s ultra low emission vehicle requirements and has a 300-km range was reported. A similar van with an electric system giving a range of 240 km was also within sight. Regarding the limitations of electric batteries it was suggested that a super capacitor may allow systems to achieve higher energy densities; a refuelable zinc-air battery could be considered for vehicle use. While the prospect for emissions improvement of gasoline vehicles has clearly improved in recent years, the relative costs of infrastructure, vehicle and fuel for the the alternative fuels compared with gasoline demonstrate the difficulty the alternative fuels have in taking market share from gasoline. For the next decade, gasoline, propane and CNG are expected to be the dominant fuels for vehicles. After that, the leading fuel will be the one that has been most extensively researched and developed during the ...
We discuss geochemical and sedimentological characteristics of 12 tephra layers, intercalated within the finely laminated sediments of Lake Van. Within the about 15 kyr long sediment record studied, volcanic activity concentrated in the periods 2.6-7.2 and 11.9-12.9 kyr B.P. Concentrations of 25 elements provide the geochemical fingerprint of each tephra layer and allow comparison to literature values of potential source volcanoes such as Mts. Nemrut and Suephan. The youngest two tephra layers (and probably also the other three ashes from the 2.6-7.2 kyr B.P. eruptions) originate from the Nemrut volcano. The source of the older tephra (11.9-12.9 kyr B.P.), however, remains unidentified.
Abstract- In our reply to M. H. van IJzendoorn and M. J. Bakermans-Kranenburg (this issue) and R. A. Thompson (this issue), we highlight 2 challenges that attachment researchers face today: (a) closing the gap between the developmental and social psychological traditions and (b) connecting attachment theory to the broader field of evolutionary psychology. We contend that an evolutionary life history approach can contribute to both goals and argue that attachment researchers should consider moving beyond some of Bowlby's original formulations in order to permit further advancement of the field. Finally, we review van IJzendoorn and Bakermans-Kranenburg's criticism of the hypothesis that sex differences in attachment arise in middle childhood; we conclude that the claim that the hypothesis h...
In this project attention is paid to possibilities to improve the cost-effectiveness of co-fermentation and thus reduce the dependency of subsidies. A calculation model has been developed by means of which is possible to change relevant parameters and determine the exploitation cost. A sensitivity analysis shows which conditions are required to improve the cost-effectiveness of the energy and CO2, produced by fermentation. [Dutch] In dit project is gezocht naar oplossingen waarmee co-vergisting financieel aantrekkelijk wordt zonder subsidies. Daarvoor is een rekenmodel ontwikkeld waarmee het mogelijk is relevante parameters te wijzigen en vervolgens de exploitatie door te rekenen. De uitgevoerde gevoeligheidsanalyse geeft aan welke randvoorwaarden noodzakelijk zijn om het vermarkten van met behulp van vergisting geproduceerde energie en CO2 rendabel te maken.
The primary of this thesis is the derivation of nonisothermal equations for isotropic viscoelastic materials with the help of the thermodynamics. Because the description of all phenomena would be too ambitious for one thesis, the area of investigation has...
This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 2000 to March 31, 2001. Summary reports of 46 papers, and lists of publication, personnel and cooperative research with universities are contained. (author)
The book deals with the redistribution of income, a subject which has acquired a lot of attention within the Dutch economic political field. According to Hoogerwerf (1983) it covers one of the few areas in which government action in the Netherlands has be...
The results of a time-resolved study of the avalanche and streamer formation phases leading to breakdown in atmospheric nitrogen and dry air. Results of experiments and two-dimensional simulations are presented. It is shown what processes are responsible for the formation of a streamer. The trends of externally measured quantities correspond with those predicted by our model. 3 figs., 5 refs.
Fermi radii and velocities are determined by deconvoluting de Haas-van Alphen data. Comparison of these data with accurate augmented-plane-wave band-structure results establishes the reliability of the augmented-plane-wave calculations and allows a determination of the anisotropic many-body enhancement factor lambda(k). The Fermi-surface average of 1.33 suggests a large electron-electron contribution. Our anisotropic lambda(k) porvides a detailed test and guide for model calculations of many-body enhancement.
This action plan describes the working group's ideas on how the grid operators should prepare themselves for the implementation of decentralized applications in the next four years. The action plan contains three main lines that reflect the main actions expected from the grid operators by the government and society: knowledge development of grid operators; definition of standard solutions; and realization through investment. Installing smart meters in dwellings in the Netherlands is being prepared and will take several years. The working group sketches the options of the smart meter cupboard and the smart meter to support the developments under the Energy Transition (ET) and assigns actions. In 2007 the working group drafted 'position papers' of the twelve transition paths and Energy Transition working groups which they anticipate will lead to several developments for the decentralized infrastructure. The working group then indicates how these developments ...
A non-linear analysis of a Cerenkov maser is presented. The system consists of a ring configuration of a cylindrical waveguide filled with a dielectric material. A single transverse-magnetic mode is assumed to propagate in the system. A low-density pencil electron beam travels in part of the ring, confined by a strong axial magnetic field. Using the single-particle description for the beam and the wave equation for the field, we obtain a set of two coupled non-linear differential equations describing the slowly varying amplitude and phase of the electromagnetic mode. The gain per path is assumed to be small and the spatial growth of the field is neglected. The resulting time dependent amplitude includes the exponential gain of the linear stage and the saturation to its maximum value. The time dependent frequency is also calculated. The two equations are combined to a single Van Der Pol equation with a non-linear restoring force. This description demonstrates the ...
As the three-year period FY93-FY96 ended, there were six senior investigators on the grant full-time: Bulgac, Henley, Miller, Savage, van Kolck and Wilets. This represents an increase of two members from the previous three-year period, achieved with only a two percent increase over the budget for FY90-FY93. In addition, the permanent staff of the Institute for Nuclear Theory (George Bertsch, Wick Haxton, and David Kaplan) continued to be intimately associated with our physics research efforts. Aurel Bulgac joined the Group in September, 1993 as an assistant professor, with promotion requested by the Department and College of Arts and Sciences by September, 1997. Martin Savage, who was at Carnegie-Mellon University, jointed the Physics Department in September, 1996. U. van Kolck continued as research assistant professor, and we were supporting one postdoctoral research associate, Vesteinn Thorssen, who joined us in September, 1995. Seven ...
An investigation was carried out to determine the significance of a large input of cogeneration units for the electric power generation, next to the input of coal and uranium. Thereto a production plant has been set up to generate heat and electric power. The plant serves as a basis for a number of comparative calculations: basic calculations to investigate the influence of some strategies on the cogeneration input, and sensitivity calculations to determine the influence of a few changes in the starting points. Some variants have been deduced from this plant, which is based on prognosis for the year 2000. By means of the computer calculation program OPINIE (Optimale Inzet en Instelling van Eenheden: Optimal Input and Installation of Units) the minimal variable costs were calculated for different situations. Finally for each considered situation the total annual costs have been calculated. 53 figs., 13 refs., 30 tabs., 3 apps.
An analysis is given of the problems which can be solved by the use of electric-powered vehicles. A detailed comparison is made of the energy consumption and the air polluting emissions of electric and conventional vehicles, taking into account the energy consumption of the vehicles and the primary energy consumption of electric power generation and automotive fuels production. Also the air pollution, as a result of power generation and fuel production are considered. In chapter 1 an outline is given of the traffic and transportation sector in the Netherlands with special attention to data on the energy consumption and the air pollution of this sector. Based on these data the problems can be formulated for which the application of electric vehicles can be a solution. In chapter three a brief description is given of the technical specifications and characteristics of electric vehicles. Special attention is paid to the battery types. The energy and environmental aspects of electric cars ...
The vortex-excited dynamics of a uniform pivoted cylinder in uniform and sheared flow was investigated experimentally. The experiments were numerically simulated using a diffusive Van der Pol oscillator model developed by Balasubramanian & Skop recently. Salient features of the experimental investigations and the numerical simulations are presented here. Comparisons between the experimentally recorded and numerically predicted structural response to vortex-excited vibrations, power spectral density measurements of near-wake velocity fluctuations and lock-in ranges are made. A comparison of the numerical predictions and the experimental data reveals good agreement.
The general usefulness of neutron activation analysis (NAA) for samples containing the platinum group elements (PGE) and Au, either as major or trace constituents, is discussed. Charged particle activation is shown to be a viable or complementary alternative. Proton (6-10 MeV) and alpha particle (9-15 MeV) beams, produced in a tandem Van de Graaff accelerator, have been established to be the most effective choice. By taking advantage of the Coulomb barrier effect and the fact that many charged particle induced reactions have relatively large threshold values, the same instrumental technique can be applied, with minor modifications, to a wide range of materials.
The general usefulness of neutron activation analysis (NAA) for samples containing the platinum group elements and Au, either as major or trace constituents, is discussed. Charged particle activation is shown to be a viable or complementary alternative. Proton (6-10 MeV) and alpha particle (9-15 MeV) beams, produced in a Tandem van de Graaff accelerator, have been established to be the most effective choice. By taking advantage of the Coulomb barrier effect and the fact that many charged particle induced reactions have relatively large threshold values, the same instrumental technique can be applied, with minor modifications, to a wide range of materials.
In the 1988 February issue of this magazine the units olf and decipol were introduced. Olf is a measure for the pollution load and decipol for the indoor air quality. This article discusses a new ventilation theory which is quantified by the new indoor air quality thermal comfort balance based on the units olf and decipol. This balance requires more ventilation air than for the present regulations. It takes into account all pollution sources. 2 figs., 9 refs., 3 tabs.
We report tests of a refuelable zinc/air battery of modular, bipolar-cell design, intended for fleet electric busses and vans. The stack consists of twelve 250-cm{sup 2} cells built of two units: (1) a copper-clad glass-reinforced epoxy board supporting anode and cathode current collectors, and (2) polymer frame providing for air- and electrolyte distribution and zinc fuel storage. The stack was refueled in 4 min. by a hydraulic transfer of zinc particles entrained in solution flow.
Within about 10 years, microelectronic devices will be made with more than a billion (10"9) electronic components per chip. To implement such a sophisticated technology it will be essential to have a fundamental understanding of the solid state interaction between the different materials in thin film semiconductor structures. This is the main purpose of this research program. Characterization and analysis is carried out mainly by Rutherford backscattering spectrometry and channelling using accelerated nuclear particles from the Van de Graaff accelerator, while radioactive isotopes provide information about interaction mechanisms. 6 figs., 1 ref.
We introduce a family of rank functions and related notions of total transcendence for Galois types in abstract elementary classes. We focus, in particular, on abstract elementary classes satisfying the condition know as tameness (currently suspected to be a necessary condition for the development of a reasonable classification theory) where the connections between stability and total transcendence are most evident. As a byproduct, we obtain a partial upward stability transfer result for tame abstract elementary classes stable in a cardinal lambda satisfying lambda^{aleph_0}, a substantial generalization of a result of Baldwin, Kueker, and VanDieren.
Magnetic behavior in three compounds RTa{sub 3}O{sub 9} (R = Nd, Eu and Ho) with defect-perovskite structures has been investigated by DC magnetic susceptibility. The susceptibility of NdTa{sub 3}O{sub 9} shows strong influence of crystal field. For EuTa{sub 3}O{sub 9} a typical Van Vleck paramagnetism has been observed. HoTa{sub 3}O{sub 9} obeys a Curie-Weiss law above 20 K. (orig.) 8 refs.
The two model MP Tandem Van de Graaff accelerators at Brookhaven have been used in a four-stage accel-decel configuration to produce highly stripped low energy heavy ions. The performance in this mode of operation has now been substantially improved by modifications of the second accelerator. The inclined field acceleration tube electrodes at the exit of this accelerator were replaced by straight electrodes, the vacuum was improved and the maximum negative terminal potential was increased. Higher intensity beams of heavier highly stripped ions can now be produced at lower energies than before.
...May 2011, 693-709 On the valuation of fader and discrete barrier options in Heston's stochastic volatility model by Susanne Griebsch & Uwe Wystup [Downloadable!... (restricted)] 863-881 Nonlinearities in stochastic clocks: trades and volume as subordinators of electronic markets by Rafael Velasco-Fuentes & Wing Lon Ng [...and estimation of stock prices and trading volume in Barndorff-Nielsen and Shephard stochastic volatility models by Friedrich Hubalek & Petra Posedel [Downloadable!... (restricted)] 665-691 Generic pricing of FX, inflation and stock options under stochastic interest rates and stochastic volatility by Alexander van Haastrecht & Antoon ...
The compressive and torsional buckling behavior of carbon nanotube bundles at room temperature is examined with classical molecular dynamics simulation. The critical compressive load and stiffness of a single carbon nanotube in the bundle are found to be similar to those of individual carbon nanotubes. However, the critical torsional moment and stiffness of a single carbon nanotube in the bundle are found to be higher than those of individual carbon nanotubes. In addition, this study demonstrates that van der Waals interactions between the nanotubes in the bundle significantly affect the critical compressive load of the nanotube bundle.
Some recent achievements in the field of high pressure vessels and safety devices have offered a concrete chance to the application of compressed hydrogen for fleet commercial vehicles for urban use. Accordingly with this concept, ENEA has modified a Fiat Ducato van with a dual fuel engine, retaining the gasoline tank for long distance travelling and adopting the external mixture formation technique, with hydrogen injectors developed by ENEA, for non-polluting short-range duties in urban traffic. The article deals with the rationale for this choice and gives a general view of the project. (author)
We study a percolation process on the planted binary tree, where clusters freeze as soon as they become larger than some fixed parameter N. We show that as N goes to infinity, the process converges in some sense to the frozen percolation process introduced by Aldous. In particular, our results show that the asymptotic behaviour differs substantially from that on the square lattice, on which a similar process has been studied recently by van den Berg, de Lima and Nolin.
The awareness of health issues related to buildings has heightened past decades. Indoor Environmental Quality (IEQ) has been addressed in most Green Building Rating Systems nowadays. This article analyses the scope of IEQ (Indoor Environmental Quality) within Rating Systems GPR Gebouw, BREEAM-NL (Dutch version of Building Research Establishment's Environmental Assessment Method) and LEED (Leadership in Energy and Environmental Design). Each Rating System allocates health aspects. However, none of these Rating Systems addresses a complete set of relevant aspects. High ratings do not guarantee healthy buildings. It is concluded that, in general, credits for energy efficiency do not interfere with credits for enhanced indoor environmental quality. [Dutch] Gezondheidsaspecten van gebouwen hebben afgelopen decennia steeds meer en integraler aandacht gekregen. In de instrumenten GPR Gebouw, BREEAM-NL (Nederlandse versien van ...
The Kadomtsev-Petviashvili equation describes nonlinear dispersive waves which travel mainly in one direction, generalizing the Korteweg-de Vries equation for purely uni-directional waves. In this Letter we derive an improved KP-equation that has exact dispersion in the main propagation direction and that is accurate in second order of the wave height. Moreover, different from the KP-equation, this new equation is also valid for waves on deep water. These properties are inherited from the AB-equation (E. van Groesen, Andonowati, 2007 ) which is the unidirectional improvement of the KdV equation. The derivation of the equation uses the variational formulation of surface water waves, and inherits the basic Hamiltonian structure.
The mature spermatozoon of Cricocephalus albus is filiform, tapered at both ends and shows the following features: 2 axonemes of different lengths presenting the 9+''1'' trepaxonematan pattern, 2 bundles of parallel cortical microtubules, a mitochondrion and a nucleus. Nevertheless, the particularity of the spermatozoon of C. albus is its anterior extremity with an apical electron-dense material associated with extramembranar ornamentation, a cytoplasmic dorsolateral expansion and spine-like bodies. To our knowledge, such an anterior extremity of the spermatozoon has not previously been described from a species of the superfamily Pronocephaloidea. Our study provides new data on the mature gamete of C. albus in order to improve our understanding of the pronocephaloidean phylogenetic relatio...
The buckling behaviors of double-walled carbon nanotubes (DWCNTs) under torsion are investigated by using molecular dynamics (MD) simulations. The effect of length on the torsional buckling behaviors of DWCNTs is examined for the first time. The simulation results show that the DWCNTs experience gradual or simultaneous buckling deformations depending on their lengths. In addition, the effect of the inner tube in a DWCNT on its torsional buckling behavior is also examined. The presence of the inner tube triggers van der Waals (vdW) interactions between it and the outer tube and thus leads to a stiffening effect of the DWCNT against torsional deformation. Whether the ends of the inner tube are free or fixed and whether it is subject to a torque or not, the critical torque and the critical torsional angle of the outer tube are only marginally affected.
We obtain conformal invariant topological field theories with N = 2 supersymmetry by twisting Sevrin, Troost and Van Proeyen's SU(2) x SU(2) x U(1) extended N = 4 superconformal field theories. We expect that the number of physical states is finite although the original N = 4 theories have continuous spectra. It is shown that the number of physical states is actually finite when the central charge c < 6 in the corresponding N = 4 theories. The physical states inherit the structure of the chiral ring in N = 2 superconformal minimal series which is obtained by the reduction from N = 4 theories. We also show that the algebra contains the topological N = 4 superconformal algebra as subalgebra. Therefore a closed set of a finite number of physical states in the topological N = 1 superconformal algebra can also be obtained. (orig.).
As the ground state potential curve is strongly related to spectral line shapes, the minumum position of the ground state potential is obtained from the experiemental absorption profile k({delta}{nu}, T) at high density of the radiating atoms. The temperature dependence of the absorption processes of Hg and Cd lines 253.65 and 326.1 nm, respectively perturbed by inert gases (Xe, Kr, Ar and Ne) had been carefully studied over a wide spectral range. Using the point of the maximum temperature dependence {delta}{nu} {sub m} in each case, we are able to calculate the position of the ground state potential R {sub m} using a simple formula.
Using gasoline as an example of additives for cold start improvement, fuel vapor composition of methanol-gasoline mixtures, fuel evaporation rate in consideration of temperature drop due to heat of fuel evaporation, air fuel ratio, stoichiometric air fuel ratio and excess air ratio of fuel vapor were calculated. The mixture formation of methanol-gasoline mixtures at low temperature in otto cycle engines was studied. Van Laar's empirical formula was used to estimate the partial pressure of high-percentage methanol blends. It was found that the most part of fuel vapor is occupied by gasoline, even when a small amount of gasoline is added to methanol resulting to an extremely small excess air ratio. It is obvious that this vapor pressure adjustment using gasoline is the dominant factor for improvement in cold startability. (10 figs, 1 tab, 10 refs)
The main purpose of the study on the title subject is to gain insight into the strategic options to optimize energy production from waste processing in the Netherlands in the long term. The developed optimization model will be used by the Dutch Ministry of Public Health, Spatial Planning en Environment (VROM) for scenarios to calculate and determine expectations and uncertainties in the development of waste processing in the Netherlands. Attention is paid to (1) the impact of present and future technology on the costs and energetic efficiency of waste processing, (2) several techniques for the generation of electricity and heat, the production of fuels, and recycling, (3) the impact of scale (capacity) on costs and energetic efficiency of waste processing installations, and (4) the impact of transport and heat distribution. The time frame is the year 2020. 66 refs.
A three-dimensional numerical study is performed to explore the effect of pulsed spanwise-periodic surface thermal perturbation (also denoted as thermal bump) in a Mach 1.5 flat plate laminar boundary layer. A high-resolution upwind-biased Roe method is used with the compressive Van Leer harmonic limiter on a suitably refined mesh. The dependence of flow stability characteristics on the variation of thermal bump geometry (shape and dimension) and pulsing properties (disturbance amplitude and frequency) is assessed. It is shown that the finite-span thermal bumps generate streamwise vortices. When the thermal bump is pulsed, vortex shedding is observed, and the streamwise vorticity grows with the downstream distance. Analysis of the integrated disturbance energy indicates that the streamwise...
Nomographs that calculate the threshold values of surface fire parameters which lead to crown fire initiation were created by linking two separate fire behavior models: Van Wagner?s crown fire ignition criteria and Byram?s surface fire model. The nomographs were also based on the existing surface (fuel load, fuel heat content) and canopy (foliar moisture content, live crown base height) fuel models of Aleppo (Pinus halepensis Mill.) pine forests of Mediterranean Greece. The most important fire parameters for crown fire initiation that are calculated by the nomographs are the critical flame length and the forward spread rate of the surface fire. These parameters are readily observable in the field during fires. The nomographs provide a judicious way to assess whether a crown fire is likely ...
A kinetic model based on the Mars-van Krevelen mechanism that allows to describe the microkinetics of the heterogeneously catalysed partial oxidation of {alpha}, {beta}-unsaturated aldehydes is presented. This conversion is represented by a network, composed of the oxidation of the {alpha}, {beta}-unsaturated aldehyde towards the {alpha}, {beta}-unsaturated carboxylic acid and the consecutive oxidation of the acid as well as the parallel reaction of the aldehyde to products of deeper oxidation. The reaction steps of aldehyde respectively acid oxidation and catalyst reoxidation have been investigated separately in transient experiments. The combination of steady state and transient experiments has led to an improved understanding of the interaction of the catalyst with the aldehyde and the carboxylic acids as well as to a support of the kinetic model assumptions. (orig.)
Lifetime observations on a group of 358 rhesus monkeys indicate that life expectancy loss from exposure to protons in the energy range encountered in the Van Allen belts and solar proton events is influenced primarily by the dose rather than the energy of radiation. After 24 years, life expectancy losses from similar surface doses of low-LET (138-2300 MeV) and high-LET (32-55 MeV) protons are not significantly different, but the high-LET protons are associated with more deaths in the early years, while the low-LET protons contribute more to mortality in later years. In males, the most significant cause of life shortening is nonleukemia cancers.
A multivariate logistic regression model, based upon National Automotive Sampling System Crashworthiness Data System (NASS-CDS) data for calendar years 1999-2008, was developed to predict the probability that a crash-involved vehicle will contain one or more occupants with serious or incapacitating injuries. These vehicles were defined as containing at least one occupant coded with an Injury Severity Score (ISS) of greater than or equal to 15, in planar, non-rollover crash events involving Model Year 2000 and newer cars, light trucks, and vans. The target injury outcome measure was developed by the Centers for Disease Control and Prevention (CDC)-led National Expert Panel on Field Triage in their recent revision of the Field Triage Decision Scheme (American College of Surgeons, 2006). The ...
In the international study of IEA Annex 27 `Demonstration and evaluation of domestic ventilation systems` a number of simple tools to gain insight into the characteristics of ventilation systems for dwellings are presented. The assessment is made with respect to e.g. indoor air quality, comfort, noise, energy, costs and reliability. In three articles the results of Annex 27 will be discussed. In the first article background information of IEA Annex 27 was given as well as applications in the Netherlands. In this second article attention is paid to the assessment models (`simplified tools`) for indoor air quality, thermal comfort and noise. 6 refs.
At the 7th Healthy Buildings Conference, which was held in Singapore, 7-11 December 2003, more than 500 articles to improve public health and productivity of workers in buildings and the performance of installations. Special attention is paid to indoor air quality and thermal comfort in relation to energy efficiency. [Dutch] Op de laatste Healthy Buildings conferentie, december 2003 in Singapore, werden meer dan 500 artikelen gepresenteerd over het creeren van gezonde, productiviteit verhogende gebouwen en installaties. Deze keer lag de nadruk op binnenluchtkwaliteit en thermisch binnenklimaat, onder andere op het aspect energiezuinigheid. Opvallend was ook de aandacht die de problemen met binnenluchtkwaliteit in ontwikkelingslanden kreeg.
The Electric Fuel zinc-air battery yielded energy densities from 6.8 to 10.2 times higher than those of the lead-acid batteries. The higher the power and the more difficult the driving cycle, the higher this ratio of energy densities grew. Not only was the Electric Fuel battery capable of extended high-power discharge, the impact of such discharge conditions on energy and driving range was show to be quite small, and was much smaller than the comparable impact on lead-acid traction batteries. At the time of writing this paper, tests are scheduled to continue with the 110-kWh battery in the Mercedes van, and preliminary plans have been made for testing of additional batteries on other vehicle types.
Limiters are nonlinear hybridization techniques that are used to preserve positivity and monotonicity when numerically solving hyperbolic conservation laws. Unfortunately, the original methods suffer from the truncation-error being first-order accurate at all extrema despite the accuracy of the higher-order method. To remedy this problem, higher-order extensions were proposed that relied on elaborate analytic and geometric constructions. Since extremum-preserving limiters are applied only at extrema, additional computational cost is negligible. Therefore, extremum-preserving limiters ensure higher-order spatial accuracy while maintaining simplicity. This report presents higher-order limiting for (i) computing van Leer slopes and (ii) adjusting parabolic profiles. This limiting preserves monotonicity and accuracy at smooth extrema, maintains stability in the presence of discontinuities and under-resolved gradients, and is based on constraining the interpolated ...
The electron-phonon spectral distribution function #alpha#"2(#omega#) F (#omega#) has been calculated for niobium. The electron energy bands and wave functions were obtained from a self-consistent augmented-plane-wave muffin-tin potential, and the electron-phonon matrix elements were evaluated using the so-called rigid-ion approximation. With this approximation it is found that #alpha#"2(#omega#) is constant over the whole energy spectrum. The electron-phonon mass enhancement has also been calculated for local regions of the Fermi surface and found to be anisotropic. The calculated local values of the enhancement do not agree with experimental values available for different orbits from de Haas--van Alphen measurements. The discrepancy seems to arise because the bare-rigid-ion matrix elements are relatively small between states with nearly pure l = 2 character.
The primary charge separation in photosynthetic bacteria generates a dimeric bacteriochlorophyll (BChl) cation and a bacteriopheophytin (BPheo) anion which lie within close proximity of each other (approx. 10 A). The two radicals also lie within van der Waals contact on opposite sides of a lone BChl bridging molecule. Spectral changes in the red (Q/sub y/) band of the bridge BChls have been observed on picosecond time scales following excitation of the reaction center (RC) and have been variously attributed to the formation of a BChl anion, to a charge-transfer state, or to electrochromic effects. They present calculations here which suggest that electrochromic effects caused by the photogenerated cation and/or anion can rationalize the optical changes observed in the flash photolyses as well as in trapping experiments.
Dimensioning of actinides waste packages for long duration storage has to take into account helium production from natural decay and release rates from the material. For the latter, we propose here an improved method for the determination of the helium diffusion coefficient in britholite, to be used for minor actinides storage. This work is based on results we previously published using the classical three steps method: "3He implantation on a Van de Graaff facility, "3He profile determination analysing the protons resulting from the "3He(d,p)"4He reaction in a nuclear microprobe, evolution of the helium profile during annealings. Taking explicitly into account the incident deuterons energy stragglings allows us to show that the implanted helium profiles are bimodal, each component leading to a different helium diffusion coefficient.
By means of a numerical simulation model (PHOENICS) the air flow and the distribution of the air concentration in an operating room of an hospital have been calculated. Comparisons were made for 11 different conditions (m[sup 3]/h air flow, speed of the air supply in the centre, the middle and outside of the room), of which six cases are discussed in this article, in order to optimize the air flow pattern in the room. The calculations were conducted for the so-called Howorth system. It is shown that the inlet velocity profile with a higher inlet velocity in the center zone of the hood gives the best results. The calculated results were validated by some measurements and experiments with smoke. 7 figs., 2 tabs., 8 refs.
A mobile gamma-ray scanning system has been developed by Oak Ridge National Laboratory for use in the U.S. Department of Energy's remedial action survey programs. The unit consists of NaI(Tl) detectors housed in a specially equipped van. The system is operator controlled through an on-board minicomputer with data output provided on the computer video screen, strip chart recorders, and an on-line printer. Data storage is provided on floppy disk. Multichannel analysis capabilities are included for qualitative radionuclide identification. A /sup 226/Ra-specific algorithm is currently employed to identify locations containing residual radium-bearing materials.
A mobile gamma-ray scanning system has been developed by Oak Ridge National Laboratory for use in the U.S. Department of Energy's remedial action survey programs. The unit consists of NaI(Tl) detectors housed in a specially equipped van. The system is operator controlled through an on-board minicomputer with data output provided on the computer video screen, strip chart recorders, and an on-line printer. Data storage is provided on floppy disk. Multichannel analysis capabilities are included for qualitative radionuclide identification. A "2"2"6Ra-specific algorithm is currently employed to identify locations containing residual radium-bearing materials.
Measurements of gamma-ray spectra, following the thermal neutron fission of "2"3"5U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products with lifetimes of the order of fractions of a second or a few ...
Prompt fission neutron spectrum measurements at the University of Massachusetts Lowell 5.5 MV Van de Graaff accelerator laboratory require that the neutron detector efficiency be well known over a neutron energy range of 100 keV to 20 MeV. The efficiency of the detector, has been determined for energies greater than 5.0 MeV using the Weapons Neutron Research (WNR) white neutron source at the Los Alamos Meson Physics Facility (LAMPF) in a pulsed beam, time-of-flight (TOF) experiment. Carbon matched polyethylene and graphite scatterers were used to obtain a hydrogen spectrum. The detector efficiency was determined using the well known H(n,n) scattering cross section. Results are compared to the detector efficiency calculation program SCINFUL available from the Radiation Shielding Information Center at Oak Ridge National Laboratory.
The classical theory of collisional broadening and shift parameters (?, ?) of an isolated spectral line was used to obtain simple analytical formulas for calculating both ? and ?. These formulas were obtained on the assumption that the short range interaction is effective only in the broadening while the long range is effective in the shift of the spectral line. These parameters ? and ? depend on the limiting phase shifts responsible for broadening ?b and shift ??. It was found that the values of ?b and ?? are not equal to each other as was proposed by Weisskopf ?b=??=1. The maximum and average values of ?b (?bmax, ?bav) and ?? (??max, ??av) were obtained by numerical evaluation, using different inverse power potentials. By introducing these parameters into the approximated formulas for ? and ? using Van der Waals and Lennard-Jones potential, it was found that the results of calculations for (? and ?) with different atomic transitions perturbed by different inert ...
We study from a critical perspective several quantum-electrodynamic phenomena commonly related to vacuum electromagnetic (EM) fluctuations in complex media. We compute the resonance-shift, the spontaneous emission rate, the local density of states and the van-der-Waals-Casimir pressure in a dielectric medium using a microscopic diagrammatic approach. We find, in agreement with some recent works, that these effects cannot be attributed to variations on the energy of the EM vacuum but to variations of the dielectric self-energy. This energy is the result of the interaction of the bare polarizability of the dielectric constituents with the EM fluctuations of an actually polarized vacuum. We have found an exact expression for the spectrum of these fluctuations in a statistically homogeneous dielectric. Those fluctuations turn out to be different to the ones of normal radiative modes. It is the latter that carry the zero-point-energy (ZPE). Concerning spontaneous ...
Data which have been collected by Los Alamos National Laboratory waste management for the hydrologic characterization of the subsurface at the low level radioactive waste disposal facility, Area G, are reported and discussed briefly. The data includes Unsaturated Flow Apparatus measurements of the unsaturated conductivity in samples from borehole G-5. Analysis compares these values to the predictions from van Genuchten estimates, and the implications for transport and data matching are discussed, especially at the location of the Vapor Phase Notch (VPN). There, evaporation drives a significant vapor flux and the liquid flux cannot be measured accurately by the UFA device. Data also include hydrologic characterization of samples from borehole G-5, Area G surface soils, Los Alamos (Cerros de Rio) basalt, Tsankawi and Cerro-Toledo layers, the Vapor Phase Notch (VPN), and additional new samples from the uppermost tuff layer at Area G. Hydraulic properties from these ...
We propose to investigate the spontaneous emission of radiation arising out of the interaction of a relativistic electron beam with a metallic grating (the Smith-Purcell effect). The work will concentrate, primarily, in the 50-120 #mu#m part of the infrared spectrum and will be an extension of the work begun by the Oxford-Dartmouth-Essex collaboration; one of the early objectives of the project will be to develop a quantitative understanding of the power spectrum of the emitted radiation over a wide range of emission angles. In particular, the limits of relativistic peaking of forward directed emission will be investigated. The electron beam will be produced by laser irradiation of a metallic cathode in the terminal of a small Van de Graff accelerator located in the Technische Universitaet, Muenchen. Beam energies will be in the range of 2 - 4 MeV. Initial tests on photoproduction of electrons have yielded 10 mA pulses with a width of about 20 ns. The electron ...
The solubilities of chlorodifluoromethane(R-22) and dichlorodifluoromethane(R-12) in organic solvents were measured in the range of low pressures and several temperatures(278-338 K). Organic solvents used in this system were olive oil and oleic acid. Henry`s law is applied in the lower temperature range and the solubilities of R-22 show negative deviations from Raoult`s law. In this study temperature and pressure dependence were correlated. The correlation of gas solubility data, using Krichevsky-Kasarnovsky equation and Van`t Hoff expression are obtained. Values of Henry`s constant, Partial enthalpy and partial entropy in organic solvents have been determined for both gases. The solubilities increase with increasing pressure and decreasing temperature and both gases are more soluble in olive oil than in oleic acid. The solubilities of R-22 in organic solvents were higher than those of R-12 because of hydrogen bonding between solvents and solutes. (author). 11 ...
In the 150 kV power system of the Dutch energy utility MEGA Limburg cross-country faults have caused problems in the protection of high voltage transmission lines. A cross-country fault is the simultaneous presence of two single-phase earth connections in different phases and places within the grid. These cross-country faults can lead to the incorrect operation of a number of distance relays, which could result in the faulty disconnection of high voltage transmission lines. To gain an insight into these problems, the transient phenomenon in the power system during cross-country faults were studied. For this purpose, the simulation program EMTP (ElectroMagnetic Transients Program) has been used. Simulation models of the 150 kV power system and the measuring system of a distance relay were developed within EMTP. 7 figs., 1 ill.
Full text: Recent geoarchaeological research in the Erzurum district, north-eastern Anatolia, has revealed an abundance of obsidian at numerous neolithic and Bronze Age sites. Geochemical characterisation using neutron activation analysis indicates that the obsidian was obtained from several sources that are chemically distinct from the major sources already known from Central Anatolia an the Lake Van area. Multiple sources are represented in the samples collected from at least two of the sites, namely the sites of Sos and Pulur. The primary source of some of the obsidian utilised at the site of Sos has been located in the volcanic sequence outcropping tot he north-west of Pasinler. Field survey however has shown that the alluvial deposits along the main rivers and some of their tributaries were the main sources of the obsidian utilised at the sites near Erzurum. Trade or exchange of obsidian with sites outside the Erzurum area seems to have been limited.
Pre-harvest sprays of bavistin (50% carbendazim) at 100, 200 and 400 g a.i/ha were ineffective in the control of Aspergillus niger van Tieghem in onion. The combination of gamma irradiation (0.1 kGy) with bavistin dust (0.33g a.i/kg bulbs) was effective to an extent of about 79% in reducing storage losses due to sprouting and rottage. This combination treatment was better than dust treatment alone and highly cost effective. Bavistin, when used as pre-harvest spray, did not leave any residue in the tissues, whereas the compound was seen to move deep into the tissues, when used as post-harvest dust treatment. Higher concentrations of carbendazim residues (2.1-3.4 mg/kg bulb) were detected in the outer scales of the bulbs, as compared to that of inner scales (0.6-1.6 mg/kg), and the residue decreased slightly with passage of storage time. (author). 19 refs., 2 tabs.
The AC susceptibility of La_xNd_1_-_xF_3 single crystals, for 0#<=#x#<=#0.1, has been measured from 1.5 up to 40 K and their DC susceptibility for 0#<=#x#<=#1 has been measured from 3 up to 300 K in magnetic fields up to 0.2 T. In both susceptibilities the magnetic fields were applied parallel to the crystallographic a-axis (perpendicular to the c-axis). The effective Bohr magneton number p_e_f_f and paramagnetic Curie temperature #theta#_p have been obtained, using the Curie-Weiss law in the temperature range 100-300 K. Also the g-values corresponding to the five Kramers doublets in the "4I_9_/_2 ground multiplet of Nd"3"+ ion in La_xNd_1_-_xF_3 have been determined in the direction perpendicular to the c-axis, using the Van Vleck theory of paramagnetic susceptibility. The effect of the dilution of the paramagnetic Nd"3"+ ions with diamagnetic La"3"+ ions is also discussed. (orig.).
The magnetic properties of a single crystal of SmNiSn with the orthorhombic {epsilon}-TiNiSi-type crystal structure have been investigated by magnetic susceptibility, magnetization and electrical resistivity measurements from 1.5 K to room temperature. Two anomalies have been found in the magnetic susceptibility, indicating an antiferromagnetic phase transition at T{sub N}=9.4 K and a second transition at 4.4 K. A large magnetic anisotropy has been found at low temperatures in the temperature and field dependencies of magnetic susceptibility and magnetization. Below 80 K, the easy axis of the magnetization is the c-axis. At T=2.0 K, the c-axis magnetization curve exhibits metamagnetic-like behavior at H{sub c}=42 kOe and reaches 0.54 emu/g at H=55 kOe, whereas for the a- and b-axis the magnetization is linear and smaller. The paramagnetic susceptibilities do not follow the Curie-Weiss law suggesting a large van Vleck contribution of the Sm ions.
A brief description of a method for producing relatively intense molecular negative ion beams for the difficult Group IIA elements is given which offers considerable improvement in terms of source operation and beam intensity stability over other methods conventionally utilized. It is particularly suited for use in cesium plasma sources such as the Aarhus geometry and axial geometry versions of the source. The method utilizes H/sub 2/ source feed gas for the production of a hydrogen-rich plasma discharge which sputters a negatively biased probe made of elemental or copper alloy material. Negative ion beams of MgH/sub 3//sup -/>=12 ..mu.. A have been realized during routine operation of the 25 MV tandem accelerator. Negative ion beam intensity data, typical source operational parameters, and examples of mass spectra associated with their production are given. Interesting intermetallic molecular negative ion beams consisting of the particular Group IIA element and a Cu alloy atom have ...
The inverse susceptibilities of the monopnictides and monochalcogenides of the light rare earths plotted vs. temperature flatten off at high temperatures. This behaviour is well explained by van Vleck paramagnetism of the excited states of the multiplet. For almost all actinide pnictides and chalcogenides a similar flattening-off is observed. Since spin orbit coupling is much stronger than in the light rare earth compounds an analogous interpretation is not possible. Susceptibility curves for uranium compounds can be fitted by adding a temperature dependent enhanced Pauli paramagnetism to the Curie-Weiss term (modified Curie-Weiss law). The high temperature susceptibility behaviour of neptunium compounds is very similar to uranium compounds i.e. an appreciable deviation from the Curie-Weiss law is only visible for the chalcogenides. The plutonium chalcogenides show a temperature independent paramagnetism, which can be explained either by a model of mixed valency, ...
The data and information collected for the Public Service Electric and Gas Company`s (PSE&G) electric vehicle demonstration program were intended to support and enhance DOE`s Electric and Hybrid Vehicle Site Operator Program. The DOE Site Operator Program is focused on the life cycle and reliability of Electric Vehicles (EVs). Of particular interest are vehicles currently available with features that are likely to be put into production or demonstrate new technology. PSE&G acquired eight GMC Electric G-Vans in 1991, and three TEVans in 1993, and conducted a program plan to test and assess the overall performance of these electric vehicles. To accomplish the objectives of DOE`s Site Operator`s test program, a manual data collection system was implemented. The manual data collection system has provided energy use and mileage data. From September 1991 to October 1994 PSE&G logged 69,368 miles on eleven test vehicles. PSE&G also demonstrated the EVs to ...
The industrial radiation processing using low energy electron beam (EB) accelerators lower than 300 keV offers high speed, safe technologies for the chemical conversion of thin layer coatings. Because of the nonselective mode of initiating chain reaction polymerization involving free radicals in synthetic coating layers and suitable substrates, the EB curing of the coatings on woods and papers has particular advantage. Hungary decided to start an up-to-date EB line to process cement-bound (CB) wood chipboards with pigmented acrylic coatings. The CB wood chipboards contain more than 60 % of portland cement and up to 40 % of wood particles. They are produced as large boads of 6 - 16 mm thickness. In their fireproof character and other aspects, they are similar to asbestos-cement boards without containing carcinagenic asbestos, and are stable against moisture and atmospheric influences. EB-cured acrylate coating improved further those properties, and makes them valuable structural ...
Delayed-neutron (DN) energy spectra following thermal neutron induced fission of /sup 239/Pu as a function of time after fission have been measured, using the beta-neutron time-of-flight (TOF) spectrometer at the University of Lowell. Thermal/epithermal neutrons were produced on the 5.5-MV Van de Graaff accelerator using the /sup 7/Li(p,n)/sup 7/Be reaction. Time spectra over the neutron energy range of 0.01-4.0 MeV were measured for seven different time intervals after fission, each interval containing varying contributions from the six delayed neutrons groups. The DN energy spectra following induced thermal fission of /sup 239/Pu are compared to those resulting from induced thermal fission of /sup 235/U for each of the seven delay time intervals. Decomposition of the measured spectra into six-group DN spectra was accomplished employing an iterative least-squares method, incorporating a constraint requiring all six-group spectra remain positive for all neutron ...
Crystals of a new ternary samarium rhenium oxide, Sm{sub 3}ReO{sub 7} were obtained by subsolidus reaction of samariumsesquioxide and rheniumdioxide (ratio 1.5:1) in sealed Pt-10Rh-tubes at 1673 K. The structure was determined by single-crystal X-ray diffraction. Sm{sub 3}ReO{sub 7} crystallizes in the orthorohombic system with unit cell dimensions a = 10.736(5), b = 7.392(3), and c = 7.519(3) in space group Cmcm (No. 63) with Z = 4. The structure consists of ReO{sub 6} octahedra, distorted SmO{sub 6} octahedra, and SmO{sub 8} prisms that are interconnected to each other to form a three-dimensional network. Rhenium has the formal oxidation state of +5 but no metal-metal bond is observed in this compound. The observed magnetization in the temperature range 4 K < T < 52 K is explained by a Curie-Weiss law modified by a temperature independent Van Vleck paramagnetism of samarium (3+).
In many experiments involving fast neutrons generated in nuclear reactions initiated by accelerator produced charged particle beams, it is important to be able to determine accurately the neutron yield from the target. A detector suitable for such applications should have: a constant efficiency over a large energy range; a fast time response; and the ability to discriminate between gamma rays and neutrons. The authors have constructed a open-quotes black neutron detectorclose quotes based on the design of Poenitz that has these characteristics. At the Lowell Van de Graaff accelerator laboratory neutrons are produced via the "7Li(p,n)"7Be reaction using a pulsed proton beam which impinges on metallic lithium targets. The pulsed beam enables the detector to be used in a time-of-flight spectrometer. Use of BC501 liquid scintillator permits neutron-gamma discrimination. The scintillator is viewed by five RCA 48796 photo tubes. The detector is housed in a massive shield ...
This report surveys the possibilities and restrictions of different construction materials for the purpose of the blades of a small stall regulated turbine. For example scaling up, material saving at decreasing of static or dynamic loads, comparisons of global costs based on prices per unit of weight, etc. For the mutual comparison of construction materials for turbine blades the starting point is a stall regulated horizontal axis turbine with a rotor diameter of 16 m and a tipvane speed of about 64 m/s. Short descriptions are given of the materials and of the applied production methods with the resulting blade geometry. The blade skins are dimensionized for storm loads after the optimalization of the blade geometry, needed for the design wind speed, is recorded. The resulting blade skins are mutually compared as for weight, mass inertia and bending stiffness. Also a comparison took place of the resulting reserve factors against load variations caused by gusts of wind and own weight, ...
A collaboration initiated in 1989 between Judy Lachvayder and Chris Cullis in response to an application for a Christa McCauliffe Fellowship has grown into a substantial program. A one week course in biotechnology, using the Cold Spring Harbor Vector van, was run in 1990. A similar one week summer course was run by Cullis for high school freshmen and sophomores. Both programs (teachers and students) have continued with support from the Edison Biotechnology Center (EBTC), U.S. Biochemical, the Howard Hughes Medical Institute and CWRU. A core of teachers from these courses were brought together by the EBTC and the Cleveland Regional Area of Biologists (CRABS) was formed. This group holds regular meetings and develops new classroom exercises. A group of master teachers from the participants have also held their own workshops at local and national meetings. A Science and Society Symposium was held in February 1994 and an equipment loan program for teachers has been ...
We present the latest developments for the radiation laboratory curriculum at the Department of Physics and Astronomy of Western Kentucky University. During the last decade, the Applied Physics Institute (API) at WKU accumulated various equipment for radiation experimentation. This includes various neutron sources (computer controlled d-t and d-d neutron generators, and isotopic 252 Cf and PuBe sources), the set of gamma sources with various intensities, gamma detectors with various energy resolutions (NaI, BGO, GSO, LaBr and HPGe) and the 2.5-MeV Van de Graaff particle accelerator. XRF and XRD apparatuses are also available for students and members at the API. This equipment is currently used in numerous scientific and teaching activities. Members of the API also developed a set of laboratory activities for undergraduate students taking classes from the physics curriculum (Nuclear Physics, Atomic Physics, and Radiation Biophysics). Our goal is to develop a set of ...
The gas phase high resolution spectroscopic study of weakly bound clusters can provide the information necessary to develop an intermolecular potential energy surface. This surface can then be used to better understand condensed phases. In this work, a tunable far infrared laser spectrometer is used to study weakly bound dimers produced in the newly developed continuous planar supersonic jet expansion apparatus. The water dimer is an extensively studied hydrogen bonded dimer. It undergoes several tunneling motions which result in splittings and perturbations of the rovibrational energy levels. A review is presented of much of the experimental and theoretical work done on water dimer, including a description of the combined fit of all the high resolution spectroscopic results by Coudert and Hougen. Also included is a discussion of the measurement of the K = 1 lower {yields} K = 2 lower band performed using the tunable far infrared laser/planar jet apparatus. The preliminary results from ...
This paper presents an overview of research conducted with the support of the Australian Institute of Nuclear Science and Engineering, at the University of Melbourne, School of Earth Sciences, Radiochemical Neutron Activation Laboratory. The primary objective of this research is to realize the high potential of the platinum group elements (PGE) and gold to the solution of petrogenetic problems, the study of magma generation and magmatic processes in mafic/ultramafic rock suites, as tracers in hydrothermal ore formation. The PGEs (Os, Ru, Ir, Pt, Pd and Rh) are among the least abundant of all elements on earth with unique properties such as high melting points, high electrical and thermal conductivity, high density, strength and toughness as alloys. They exhibit both siderophile and chalcophile characteristics and are valuable tools in providing information about magmatic processes, in particular S-saturation, as well as crystal fractionation trends. Two distinct groups of PGEs are ...
The study concerns 1984-1991. The wind park consists of 18 three-bladed 300 kW horizontal axis wind turbines of 35 meters height, and a rotor diameter of 30 meters, seven meteorological towers, and three cluster and control buildings. Aspects studied included disturbance of breeding, resting or feeding, and migrating birds, behavior of birds approaching the wind turbines during the day and night, and bird victims due to collision with the wind turbines and the meteorological towers. The flight behavior of birds approaching the wind park system during daylight is also dealt with. For at least a fifth of the observations it was noted whether the birds passing within 100 meters distance of a turbine showed a reaction or not. The proportion of the reactions was related to the wind park in operation or not in operation, and to the distance between the wind turbines, species, flight height, the passing distance, wind direction and wind force. Secondly the flight path of birds approaching the ...
The neutron-capture cross sections of "1"6"8Yb, "1"8"0W, "1"8"4Os, "1"9"0Pt, and "1"9"6Hg have been measured by means of the activation technique. The samples were irradiated in a quasistellar neutron spectrum of kT=25 keV, which was produced at the Karlsruhe 3.7-MV Van de Graaff accelerator via the "7Li(p,n)"7Be reaction. Systematic uncertainties were investigated in repeated activations with different samples and by variation of the experimental parameters, that is, irradiation times, neutron fluxes, and #gamma#-ray counting conditions. The measured data were converted into Maxwellian-averaged cross sections at kT=30 keV, yielding 1214#+-#61, 624#+-#54, 590#+-#43, 511#+-#46, and 201#+-#11 mb for "1"6"8Yb, "1"8"0W, "1"8"4Os, "1"9"0Pt, and "1"9"6Hg, respectively. The present results either represent first experimental data ("1"6"8Yb, "1"8"4Os, and "1"9"6Hg) or could be determined with significantly reduced uncertainties ("1"8"0W and "1"9"0Pt). These measurements ...
This Report of activity displays the work developed at Centre d`Etude Nucleaires de Bordeaux-Gradignan (CENBG) in the period 1995-1996. A number of 68 short progress notes are presented in the fields of Cosmic particles (3), Nuclear Astrophysics (4), High Spins-Large Deformations (8), Basic Interactions (9), Exotic Nuclei (10), Hybrid Systems (4), Theoretical Physics (28), Cellular Microanalysis by means of Nuclear Probes (3) and Technical Development (3). The main problems attacked at CENBG, established as orientations by scientific board of IN2P3 (CENBG is a UMR of Bordeaux-1 Univ. and CNRS-IN2P3) are the following: the research of Majorana/Dirac nature of neutrino (in the framework of NEMO Experiment) in relation with the problem of origin of mass in the Universe and the cosmological puzzle of dark matter, the investigation of the origin of high energy (20 to 200 GeV) cosmic radiation (in the framework of CELESTE Experiment), the study of extreme issues in nuclear structure as high ...
Space particles act on semiconductor devices by creating charges (electrons, holes) in the silicon and the silicon dioxide, and by creating displacement damage. These primary phenomena alter the electrical parameters of MOS and bipolar devices (threshold voltage V_t, mobility #mu#, conductivity #sigma#, current gain #beta#). The dose rate is not important in space (a few rad (Si)/h) but as the durations of space expeditions are on average from seven to twelve years, the total dose is an aggravating factor in the behaviour of the electrical parameters and also in device operation. The total dose effect from the beginning of charge creation (ionization) to the parameter shifts is reviewed. One can note that this effect is permanent because there will almost always be charge creation in space. Another important phenomenon is called the Single Event Upset (S.E.U.) and caused by the heavy ions and the protons which come from the galactic rays. The consequence of S.E.U. is a transient upset ...
Prompt fission neutron energy spectra for "2"3"5U and "2"3"9Pu have been measured for fission neutron energies greater than the energy of the incident neutrons inducing fission. The measurements were undertaken to investigate the shape dependence of the fission neutron spectra upon both the incident neutron energy and the mass of the nucleus undergoing fission. Measurements were made for both nuclides at incident neutron energies of 0.50, 1.50, 2.50 and 3.50 MeV. The data are presented either as relative yields or as ratios of measured spectra to that of "2"3"5U at 0.50 MeV. Incident neutrons were produced by the "7Li(p,n)"7Be reaction using a pulsed, bunched proton beam from the 5.5 MV Van de Graaff accelerator at the University of Massachusetts Lowell Radiation Laboratory. Fission neutrons were detected by a thin liquid scintillator with good time resolution capabilities. Neutron energies were determined by time-of-flight techniques with pulse-shape ...
Four trypsin inhibitor homologs, the first known from Dendroaspis angusticeps venom, were characterized using a combination of gel filtration, cation exchange, reverse-phase liquid chromatography, Edman degradation and mass spectrometry. The four toxins comprise two 57 residue and two 59 residue isoforms. The long toxins possess a Lys-Gln N-terminal extension lacked by the short toxins. The only other structural difference is an Arg/His replacement at position 55. The long Arg55 variant is identical to trypsin inhibitor E from the venom of Dendroaspis polylepis. The name epsilon-dendrotoxin is suggested so as to follow the nomenclature of Benishin, C.G., Sorensen, R.G., Brown, W.E., Krueger, B.K., Blaustein, M.P., 1988. Four polypeptide components of green mamba venom selectively block certain potassium channels in rat brain synaptosomes. Mol. Pharmacol. 34, 152-159. Among snake venom protease inhibitors, the epsilon-dendrotoxins are structurally most like the delta-dendrotoxins, with ...
A recent road test at LLNL underscored the zinc/air battery`s capacity to give electric vehicles some of the attractive features of gas-driven cars: a 400-km range between refueling, 10-minute refueling, and highway-safe acceleration. Developed at Lawrence Livermore National Laboratory, the battery weights only one-sixth as much as standard lead/acid batteries and occupies one-third the space, yet costs less per mile to operate. What`s more, because the battery is easily refuelable, it promises trouble-free, nearly 24-hour-a-day operation for numerous kinds of electric vehicles, from forklifts to delivery vans and possibly, one day, personal automobiles. The test of a Santa Barbara Municipal Transit bus with a hybrid of zinc/air and lead/acid batteries capped a short development period for the zinc/air battery. The test run indicated the zinc/air battery`s potential savings in vehicle weight from 5.7 to 4.0 metric tons, in battery weight from 2.0 to 0.3 metric ...
From the crystal field analysis of optical absorption spectra on monoclinic S.G. P2{sub 1}/c MgNd(BO{sub 2}){sub 5}, where Nd{sup 3+} occupies a single crystallographic position with no symmetry elements, energy level schemes and an expression of the associated wavefunctions for the 4f{sup 3} configuration of Nd{sup 3+} have been derived, considering approximate C{sub 2v} and C{sub s} (C{sub 2}) symmetries. Despite of the low symmetry of Nd{sup 3+}, resulting rms deviations between calculated and experimental levels are very satisfactory. The composition of the crystal field wavefunctions from both sets of phenomenological free-ion and crystal field parameters has been checked through a calculation of the thermal evolution of the paramagnetic susceptibility {chi}, according to the Van Vleck formula. The same simulation was performed with crystal field parameters (CFPs) resulting from the ab initio simple overlap model (SOM), considering the Nd{sup 3+} real point ...
Neutron reflectometry (NR) was used to measure the concentration profile of a symmetric PEP/dPEP polymer blend with nanometer-scale resolution in the one-phase region. The shape of the profile near the surface was found to differ significantly from mean-field theory predictions for all bulk concentrations and temperatures surveyed. The profile shape is flattened at the surface over a distance about half the bulk correlation length, a length scale far greater than that of the dispersive forces that are the dominant microscopic interaction in such blends. We introduce a new method for extracting the surface energy difference that drives segregation based on the Gibbs adsorption equation (GAE) and compare it to a previous method based on mean-field theory. While both methods produce qualitatively similar results (the surface energy of pure dPEP is {approx}0.21 mJ/m{sup 2} smaller than pure PEP), the GAE method is much less model dependent, requiring knowledge of only the free energy of ...
The magnetic susceptibility of powdered samples of HoH_3, ErH_3, GdH_3 and YbH_3 have been measured in the temperature range from 4.2 to 1.2 K. Two broad, local maxima are observed in the variation of chi versus T for GdH_3, with maxima in (delta chi/delta T) versus T at 1.8 K and 3.3 K. The inverse susceptibilities for HoH_3 and ErH_3 both obey a Curie--Weiss law over a limited range (4.2 to 2.6 K and 4.2 to 2 K, respectively) with values for the Weiss constant of -4.25 K and -1.11 K, and effective moments of 8.6 and 7.7 Bohr magnetons, respectively. The susceptibility of YbH_3 is independent of temperature over the range investigated. High-field magnetization measurements yield extrapolated saturation moments of 7.0 +- 0.25 Bohr magnetons/ion for GdH_3, 6.1 +- 0.2 Bohr magnetons/ion for HoH_3 and 3.74 +- 0.11 Bohr magnetons/ion for ErH_3. In addition, ErH_3 exhibits a van Vleck paramagnetism in the high-field region.
Six intermetallic alloys (CeNi/sub 5/, MmNi/sub 5/, Ca/sub 0/ /sub 2/(Ce/sub 0/ /sub 65/Mm/sub 0/ /sub 35/)/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Ce/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Mm/sub 0/ /sub 8/Ni/sub 5/, and a mixed alloy, CeNi/sub 5//MmNi/sub 5/) were investigated with respect to their suitability to provide high hydrogen capacity and their potential for use in providing substantial hydrogen pressure at both low and high temperatures. A second phase of our investigation dealt with ball-milling and hydriding and dehydriding cycles to produce fine particles for use in hydride powder transfer studies. A summary of several Van't Hoff plots is also included for hydride-forming alloys.
Crystals of disamarium rhenium (IV) pentoxide, Sm{sub 2}ReO{sub 5}, were obtained by subsolidus reaction of samariumsesquioxide and rheniumdioxide (ratio 1:1) in sealed Pt 10Rh tubes at 1673 K. The structure was determined by single-crystal X-ray diffraction. Sm{sub 2}ReO{sub 5} crystallizes in the tetragonal system with unit cell dimensions a = 8.646(3) {angstrom} and c = 5.747(2) {angstrom} and space group P4/n (no. 85) with Z = 4. The structure consists of isolated RE{sub 2}O{sub 8} groups and the (Sm{sub 4}O) chains are inter-connected by common oxygen atoms to form a three-dimensional network. Each Re{sub 2}O{sub 8} group is composed of a pair of rhenium each surrounded by four oxygens with a short Re-Re distance of 2.251(1) {angstrom} indicating a metal-metal bond. Rhenium has the formal oxidation state of +4. The observed magnetizations in the temperature range 1.8 < T < 100 K exhibits antiferromagnetic ordering below 2.4(1) K and obey a Curie-Weiss law modified by a ...
Three systems for the heat supply in the built environment have been compared for the costs, the energy consumption and emissions of CO{sub 2}, NO{sub x} and SO{sub 2}. The heating systems compared are based on central heating boilers, district heating systems in combination with combined steam and gas turbine cycles, and heating by means of several gas engines. From the results it appears that the boilers demand the lowest investments. The district heating systems are more expensive. Both heating systems, however, show considerable savings of energy (55 to 70%). The exploitation costs depend strongly on the fuel price scenarios used and the assumptions with regard to interest and inflation. The emissions of CO{sub 2} are also considerably lower for both combined heat and power generating systems. The use of gas engines results in higher acidifying emissions compared to the system with the central heating boilers, and lower acidifying emissions compared to the district heating system. ...
A recently developed neutron diagnostic probe system has the potential to satisfy a significant number of van-mobile and fixed- portal requirements for nondestructive verification of sealed munitions and detection of contraband explosives and drugs. The probe is based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons generated from the deuterium-tritium reaction and that detects the alpha-particle associated with each neutron. Gamma-ray spectra of resulting neutron inelastic scattering and fission reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. Flight times determined from determined from detection times of the gamma-rays and alpha-particles yield a separate tomographic image of each identified nuclide. The APSTNG also ...
Boron Neutron Capture Therapy (BNCT) is a promising binary treatment modality for high-grade primary brain tumors (glioblastoma multiforme, GM) and other cancers. BNCT employs a boron-10 containing compound that preferentially accumulates in the cancer cells in the brain. Upon neutron capture by {sup 10}B energetic alpha particles and triton released at the absorption site kill the cancer cell. In order to gain penetration depth in the brain Fairchild proposed, for this purpose, the use of energetic epithermal neutrons at about 10 keV. Phase I/II clinical trials of BNCT for GM are underway at the Brookhaven Medical Research Reactor (BMRR) and at the MIT Reactor, using these nuclear reactors as the source for epithermal neutrons. In light of the limitations of new reactor installations, e.g. cost, safety and licensing, and limited capability for modulating the reactor based neutron beam energy spectra alternative neutron sources are being contemplated for wider implementation of this ...
The extensive research and development effort was initiated by the U.S. Department of Energy (DOE) in 2002 at West Virginia University (WVU) in order to investigate practical ways of reducing the structural weight and increasing the durability of heavy vehicles through the judicious use of lightweight composite materials. While this project was initially focused on specific Metal Matrix Composite (MMC) material, namely Aluminum/Silicon Carbide (Al/SiC) commercially referenced as ''LANXIDE'', the current research effort was expanded from the component level to the system level and from MMC to other composite material systems. Broadening the scope of this research is warranted not only by the structural and economical deficiencies of the ''LANXIDE'' MMC material, but also by the strong coupling that exists between the material and the geometric characteristics of the structure. Such coupling requires a truly ...
Delayed neutron energy spectra have been measured for six delay-time intervals following the fast fission of "2"3"8U nuclei. The delay-time intervals span the range 0.17 to 10.2 seconds following initial fission while the measured spectra span neutron energies from 10 keV to 4 MeV. The experiment was performed utilizing the UMass/Lowell 5.5 MV Van de Graff accelerator to produce fast neutrons for inducing fission in a "2"3"8U lined fission chamber. The fission fragments were flushed via a helium jet stream to a well-shielded counting room where they were deposited onto a moving tape (magnetic audio tape) and transferred to a beta-neutron time-of-flight spectrometer. By adjusting the tape speed, composite delayed neutron time-of-flight spectra were measured for several different delay-time intervals. These measurements involved beta-neutron coincidences with "6Li-loaded glass scintillators for neutron energies from 10 keV to 450 keV and Bicron BC 501 liquid ...