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1

Radioisotope production linac  

SciTech Connect

A 70-MeV proton beam would open a new family of medical radioisotopes (including the important /sup 123/I) to wide application. A 70-MeV, 500-..mu..A linac is described, based on recent innovations in accelerator technology. It would be 27.3 m long, cost approx. $6 million, and the cost of power deposited in the radioisotope-production target is comparable to existing cyclotrons. By operating the rf-power system to its full capability, the same accelerator is capable of producing a 1140-..mu..A beam, and the cost per beam watt on the target is less than half that of comparable cyclotrons. The technology to build such a linac is in a mature stage of developmnt, ready for use by industry.

Stovall, J.E.; Hansborough, L.D.; O'Brien, H.A.

1981-01-01

2

BEST medical radioisotope production cyclotrons  

NASA Astrophysics Data System (ADS)

Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 ?A to 1000 ?A, depending on the cyclotron energy and application [1].

Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Gelbart, W. Z.; Johnson, Richard R.

2013-04-01

3

Radioisotope Production for Medical and Physics Applications  

NASA Astrophysics Data System (ADS)

Radioisotopes are critical to the science and technology base of the US. Discoveries and applications made as a result of the availability of radioisotopes span widely from medicine, biology, physics, chemistry and homeland security. The clinical use of radioisotopes for medical diagnosis is the largest sector of use, with about 16 million procedures a year in the US. The use of ^99Mo/^99mTc generator and ^18F make up the majority, but ^201Tl, ^123I, ^111In, and ^67Ga are also used routinely to perform imaging of organ function. Application of radioisotopes for therapy is dominated by use of ^131I for thyroid malignancies, ^90Y for some solid tumors, and ^89Sr for bone cancer, but production of several more exotic species such as ^225Ac and ^211At are of significant current research interest. In physics ^225Ra is of interest for CP violation studies, and the actinides ^242Am, ^249Bk, and ^254Es are needed as targets for experiments to create superheavy elements. Large amounts of ^252Cf are needed as a fission source for the CARIBU experiment at ANL. The process of radioisotope production is multidisciplinary. Nuclear physics input based on nuclear reaction excitation function data is needed to choose an optimum target/projectile in order to maximize desired isotope production and minimize unwanted byproducts. Mechanical engineering is needed to address issues of target heating, induced mechanical stress and material compatibility of target and claddings. Radiochemists are involved as well since chemical separation to purify the desired final radioisotope product from the bulk target and impurities is also usually necessary. Most neutron rich species are produced at a few government and university reactors. Other radioisotopes are produced in cyclotrons in the commercial sector, university/hospital based facilities, and larger devices at the DOE labs. The landscape of US facilities, the techniques involved, and current supply challenges will be reviewed.

Mausner, Leonard

2012-10-01

4

Fast-neutron production of radioisotopes  

NASA Astrophysics Data System (ADS)

The production of radioisotopes by fast neutron reactions may be especially useful in lieu of the recent problems with reactor production in the U.S. Some of the fast neutron (n,2n) nuclear reactions are quite large and may be used to produce radioisotopes with little additional radioactive waste. For example, 99mTc, which is used for more than 80% of the diagnostic imaging in nuclear medicine, is generated from 99Mo. The 100Mo (n,2n) 99Mo reaction has a cross section of 1400 mb for 14 MeV neutrons and is a good candidate for 99Mo production.

McDaniel, F. D.; Courtney, W. J.; Givens, W. W.; Cloud, W. B.; Freeman, B. L.; Morgan, I. L.; Schafer, R. R.

1995-03-01

5

Actinium Radioisotope Products of Enhanced Purity.  

National Technical Information Service (NTIS)

A product includes actinium-225 (.sup.225Ac) and less than about 1 microgram (.mu.g) of iron (Fe) per millicurie (mCi) of actinium-225. The product may have a radioisotopic purity of greater than about 99.99 atomic percent (at %) actinium-225 and daughter...

D. H. Melkrantz E. P. Horwitz T. A. Todd T. J. Tood T. J. Tranter

2006-01-01

6

Nuclear modeling applied to radioisotope production  

SciTech Connect

Calculated excitation functions are provided for all proton-induced reactions listed for the Coordinated Research Program (CRP) on Development of a Reference Charge Particle Cross Section Data Base for Medical Radioisotope Production under the IAEA. The excitation functions are compared with experimental data sets as provided to the CRP. We discuss the merit of calculated results with respect to the experimental data.

Mustafa, M.G.; Blann, M.

1997-03-19

7

Technical and Economical Availability of Radioisotopes Production in Brazil.  

National Technical Information Service (NTIS)

The technical and economical availability of radioisotopes production in Brazil by a low power research reactor, are discussed.. The importance of radioisotope utilization and controled radiations, in areas such as medicine, industry and cost evaluation f...

J. O. V. Lima

1981-01-01

8

ELECTROLYTIC PRODUCTION OF BORON  

Microsoft Academic Search

Elemental boron was produced by the fused salt electrolysis of potassium ; fluoborate. A study was made of anode and cathode materials of construction, ; particularly the effect of various grades of graphite as anode material. The ; effect of additives to the electrolyte (including potassium, aluminum, calcium, ; vanadium, nickel, Inconel, water, and sulfate ion) on boron yield and

George T. Miller

1959-01-01

9

Radioisotope production at the Kazakhstan cyclotron  

Microsoft Academic Search

Cyclotrons play an important role for production of carrier-free radioisotopes for various applications in the nuclear medicine, industry, ecology and science. Kazakhstan variable energy isochronous cyclotron, K = 50 MeV, is a 150 cm compact-pole 3 sector positive ion machine. It generates different beams of light ions: protons 6-30 MeV, deuterons 12.5-25 MeV, 3He-ions 18.5-62 MeV, alpha-particles 25-50 MeV. In

A. Arzumanov; V. Batischev; N. Berdinova; A. Borissenko; G. Chumikov; N. Gorodisskaya; A. Knyazev; V. Koptev; S. Lyssukhin; Yu. Popov; G. Sychikov; D. Zheltov

2003-01-01

10

Alternate Applications of Fusion - Production of Radioisotopes  

SciTech Connect

A major effort to find near-term, non-electric applications of fusion energy has shown that the production of radioisotopes is attractive. The use of the D{sup 3}He fusion reaction to produce Positron Emission Tomography (PET) isotopes is described. An Inertial Electrostatic Confinement (IEC) device is particularly well suited to produce low levels of high-energy (14.7 MeV) protons, which in turn, can produce short-lived PET isotopes. The IEC device at University of Wisconsin has been modified to investigate the potential of this process to be commercially attractive.

Kulcinski, G.L.; Weidner, J.; Cipiti, B.; Ashley, R.P.; Santarius, J.F.; Murali, S.K.; Piefer, G.; Radel, R. [University of Wisconsin-Madison (United States)

2003-09-15

11

Development of Water Target for Radioisotope Production  

NASA Astrophysics Data System (ADS)

Ongoing studies of plant physiology at TUNL require a supply of nitrogen-13 for use as a radiotracer. Production of nitrogen-13 using a water target and a proton beam follows the nuclear reaction 16-O(p,a)13-N. Unfortunately the irradiation of trace amounts of oxygen-18 within a natural water target produces fluorine-18 by the reaction 18-O(p, n)18-F. The presence of this second radioisotope reduces the efficacy of nitrogen-13 as a radiotracer. Designing a natural water target for nitrogen-13 production at TUNL required the design of several new systems to address the problems inherent in nitrogen-13 production. A heat exchanger cools the target water after irradiation within the target cell. The resulting improved thermal regulation of the target water prevents the system from overheating and minimizes the effect of the cavitations occurring within the target. Alumina pellets within a scrubbing unit remove the fluorine-18 contamination from the irradiated water. The modular design of the water target apparatus makes the system highly adaptable, allowing for easy reuse and adaptation of the different components into future projects. The newly designed and constructed water target should meet the current and future needs of TUNL researchers in the production of nitrogen-13.

Tripp, Nathan

2011-10-01

12

Radioisotope production and management at Oak Ridge National Laboratory  

SciTech Connect

The production of radioisotopes has been one of the basic activities at Oak Ridge since the end of World War II. The importance of this work was best described by Alvin Weinberg, former Laboratory Director, when he wrote ``... If God has a golden book and writes down what it is that Oak Ridge National Laboratory did that had the biggest influence on science, I would guess that was the production and distribution of isotopes.`` Radioisotopes production continues to be an important aspect of Oak Ridge programs today and of those planned for the future. Past activities, current projects, and future plans and potentials will be described briefly in this paper. Also, some of the major issues facing the continued production of radioisotopes will be described. The scope of the program has always been primarily that of process development, followed by special batch-type productions, where no other supply exists. The technology developed has been available for adoption by US commercial corporations, and in cases where this has occurred, Oak Ridge has withdrawn as a supplier of the particular isotopes involved. One method of production that will not be described is that of target bombardment with an accelerator. This method was used at Oak Ridge prior to 1978 in the 86-inch Cyclotron. However, this method has not been used at Oak Ridge since then for radioisotope production, except as a research tool.

Collins, E.D.; Aaron, W.S.; Alexander, C.W.; Bigelow, J.E.; Parks, J.T.; Tracy, J.G.; Wham, R.M.

1994-09-01

13

Optimization of commercial scale photonuclear production of radioisotopes  

NASA Astrophysics Data System (ADS)

Photonuclear production of radioisotopes driven by bremsstrahlung photons using a linear electron accelerator in the suitable energy range is a promising method for producing radioisotopes. The photonuclear production method is capable of making radioisotopes more conveniently, cheaply and with much less radioactive waste compared to existing methods. Historically, photo-nuclear reactions have not been exploited for isotope production because of the low specific activity that is generally associated with this production process, although the technique is well-known to be capable of producing large quantities of certain radioisotopes. We describe an optimization technique for a set of parameters to maximize specific activity of the final product. This set includes the electron beam energy and current, the end station design (an integrated converter and target as well as cooling system), the purity of materials used, and the activation time. These parameters are mutually dependent and thus their optimization is not trivial. 67Cu photonuclear production via 68Zn(?p)67Cu reaction was used as an example of such an optimization process.

Bindu, K. C.; Harmon, Frank; Starovoitova, Valeriia N.; Stoner, Jon; Wells, Douglas P.

2013-04-01

14

Spallation production of neutron deficient radioisotopes in North America  

SciTech Connect

The US Department of Energy produces a number of neutron deficient radioisotopes by high energy proton induced spallation reactions in accelerators at Los Alamos National Laboratory in New Mexico and Brookhaven National Laboratory in New York. Research isotopes are also recovered from targets irradiated at TRIUMF in British Columbia, Canada. The radioisotopes recovered are distributed for use in nuclear medicine, environmental research, physics research, and industry worldwide. In addition to the main product line of Sr-82 from either Mo or Rb targets, Cu-67 from ZnO targets, and Ge-68 and RbBr targets, these irradiation facilities also produce some unique isotopes in quantities not available from any other source such as Al-26, Mg-28, Si-32, Ti-44, Fe-52, Gd-148, and Hg-194. The authors will describe the accelerator irradiation facilities at the Los Alamos and Brookhaven National Laboratories. The high level radiochemical processing facilities at Los Alamos and brief chemical processes will be described.

Jamriska, D.J.; Peterson, E.J. [Los Alamos National Lab., NM (United States); Carty, J. [Dept. of Energy, Germantown, MD (United States). Office of Isotope Production and Distribution

1997-12-31

15

Production of radioisotopes by direct electron activation.  

PubMed

High-energy electrons bombarded on materials can induce radioactivity by either directly knocking out neutrons or by first converting a fraction of the electron kinetic energy into electromagnetic energy, with subsequent neutron emission induced by the photons produced. The purpose of this paper was to develop a calculation method for estimating neutron emission and radionuclide production by high-energy (15-25 MeV) electrons directly interacting with a nucleus. The reaction (e,n) is considered using the method of virtual photons. The cross section for electron bombardment of lead, tantalum, rhenium, and tungsten targets is calculated. The electron cross sections are roughly 100 times less than the corresponding photon cross sections. The cross section increases monotonically with incident energy. A traveling wave linear accelerator was used for a qualitative test of the magnitude and energy dependence of the calculated cross sections. Tantalum was bombarded with electrons and the resultant emission of neutrons was inferred from the induced activation of 180Ta. The energy dependence and magnitude of the calculated electron cross sections agree with experiment within experimental uncertainties. It is concluded that accurate estimates of electron activation via the direct process is possible. PMID:9571615

Weeks, K J; O'Shea, P G

1998-04-01

16

Reactor production and processing of radioisotopes for therapeutic applications in nuclear medicine  

SciTech Connect

Nuclear reactors continue to play an important role in providing radioisotopes for nuclear medicine. Many reactor-produced radioisotopes are ``neutron rich`` and decay by beta-emission and are thus of interest for therapeutic applications. This talk discusses the production and processing of a variety of reactor-produced radioisotopes of current interest, including those produced by the single neutron capture process, double neutron capture and those available from beta-decay of reactorproduced radioisotopes. Generators prepared from reactorproduced radioisotopes are of particular interest since repeated elution inexpensively provides many patient doses. The development of the alumina-based W-188/Re-188 generator system is discussed in detail.

Knapp, F.F. Jr.; Mirzadeh, S.; Beets, A.L.

1995-02-01

17

Lightweight Radioisotope Heater Unit (LWRHU) production for the Cassini mission  

SciTech Connect

The Lightweight Radioisotope Heater Unit (LWRHU) is a {sup 238}PuO{sub 2} fueled heat source designed to provide a thermal watt of power for space missions. The LWRHU will be used to maintain the temperature of various components on the spacecraft at the required level. The heat source consists of a {sup 238}PuO{sub 2} fuel pellet, a Pt-30Rh capsule, a pyrolytic graphite insulator, and a woven graphite aeroshell assembly. Los Alamos has fabricated 180 heater units, which will be used on the Cassini mission. This report summarizes the specifications, fabrication processes, and production data for the heat sources fabricated at Los Alamos.

Rinehart, G.H.

1996-06-01

18

Reactor production and processing of radioisotopes for therapeutic applications in nuclear medicine  

Microsoft Academic Search

Nuclear reactors continue to play an important role in providing radioisotopes for nuclear medicine. Many reactor-produced radioisotopes are ``neutron rich`` and decay by beta-emission and are thus of interest for therapeutic applications. This talk discusses the production and processing of a variety of reactor-produced radioisotopes of current interest, including those produced by the single neutron capture process, double neutron capture

F. F. Jr. Knapp; S. Mirzadeh; A. L. Beets

1995-01-01

19

Reactor production and processing of therapeutic radioisotopes for applications in nuclear medicine  

Microsoft Academic Search

In this paper the reactor production of a variety of therapeutic radionuclides of current clinical interest are discussed. Examples include radioisotopes produced by single neutron capture and those which are available from –\\/decay of reactor-produced parent radioisotopes. Two examples of generator parents produced by double neutron capture of targets are also discussed. One key example in this category is188W, produced

S. Mirzadeh; A. L. Beets

1996-01-01

20

Stabilization and shutdown of Oak Ridge National Laboratory's Radioisotopes Production Facility.  

National Technical Information Service (NTIS)

The Oak Ridge National Laboratory (ORNL) has been involved in the production and distribution of a variety of radioisotopes for medical, scientific and industrial applications since the late 1940s. Production of these materials was concentrated in a numbe...

R. E. Eversole

1992-01-01

21

Production capabilities in US nuclear reactors for medical radioisotopes  

Microsoft Academic Search

The availability of reactor-produced radioisotopes in the United States for use in medical research and nuclear medicine has traditionally depended on facilities which are an integral part of the US national laboratories and a few reactors at universities. One exception is the reactor in Sterling Forest, New York, originally operated as part of the Cintichem (Union Carbide) system, which is

S. Mirzadeh; A. P. Callahan; F. F. Jr. Knapp; R. E. Schenter

1992-01-01

22

Boron modified molybdenum silicide and products  

DOEpatents

A boron-modified molybdenum silicide material is disclosed having the composition comprising about 80 to about 90 weight % Mo, about 10 to about 20 weight % Si, and about 0.1 to about 2 weight % B and a multiphase microstructure including Mo{sub 5}Si{sub 3} phase as at least one microstructural component effective to impart good high temperature creep resistance. The boron-modified molybdenum silicide material is fabricated into such products as electrical components, such as resistors and interconnects, that exhibit oxidation resistance to withstand high temperatures in service in air as a result of electrical power dissipation, electrical resistance heating elements that can withstand high temperatures in service in air and other oxygen-bearing atmospheres and can span greater distances than MoSi{sub 2} heating elements due to improved creep resistance, and high temperature structural members and other fabricated components that can withstand high temperatures in service in air or other oxygen-bearing atmospheres while retaining creep resistance associated with Mo{sub 5}Si{sub 3} for structural integrity. 7 figs.

Meyer, M.K.; Akinc, M.

1999-02-02

23

Boron modified molybdenum silicide and products  

DOEpatents

A boron-modified molybdenum silicide material having the composition comprising about 80 to about 90 weight % Mo, about 10 to about 20 weight % Si, and about 0.1 to about 2 weight % B and a multiphase microstructure including Mo.sub.5 Si.sub.3 phase as at least one microstructural component effective to impart good high temperature creep resistance. The boron-modified molybdenum silicide material is fabricated into such products as electrical components, such as resistors and interconnects, that exhibit oxidation resistance to withstand high temperatures in service in air as a result of electrical power dissipation, electrical resistance heating elements that can withstand high temperatures in service in air and other oxygen-bearing atmospheres and can span greater distances than MoSi.sub.2 heating elements due to improved creep resistance, and high temperature structural members and other fabricated components that can withstand high temperatures in service in air or other oxygen-bearing atmospheres while retaining creep resistance associated with Mo.sub.5 Si.sub.3 for structural integrity.

Meyer, Mitchell K. (Idaho Falls, ID); Akinc, Mufit (Ames, IA)

1999-02-02

24

The plasma separation process as a pre-cursor for large scale radioisotope production  

NASA Astrophysics Data System (ADS)

Radioisotope production generally employs either accelerators or reactors to convert stable (usually enriched) isotopes into the desired product species. Radioisotopes have applications in industry, environmental sciences, and most significantly in medicine. The production of many potentially useful radioisotopes is significantly hindered by the lack of availability or by the high cost of key enriched stable isotopes. To try and meet this demand, certain niche enrichment processes have been developed and commercialized. Calutrons, centrifuges, and laser separation processes are some of the devices and techniques being employed to produce large quantities of selective enriched stable isotopes. Nevertheless, the list of enriched stable isotopes in sufficient quantities remains rather limited and this continues to restrict the availability of many radioisotopes that otherwise could have a significant impact on society. The Plasma Separation Process is a newly available commercial technique for producing large quantities of a wide range of enriched isotopes and thereby holds promise of being able to open the door to producing new and exciting applications of radioisotopes in the future. .

Stevenson, Nigel R.

2001-07-01

25

Production & marketing of radioisotopes: A vital market for rare earths & specialty metals  

SciTech Connect

Isotopes that spontaneously emit alpha ({alpha}) or beta ({beta}) particles, or gamma rays ({gamma}), are said to be radioactive. The emission process, called {open_quotes}decay,{close_quotes} is precisely what makes radioactive isotopes, known as {open_quotes}radioisotopes,{close_quotes} useful in a variety of applications, including nuclear medicine, commercial sterilization, manufacturing, geophysics, agriculture, and research programs in these and various other fields. Until 1960, radioisotope production was limited to government-owned nuclear reactors and particle accelerators in universities and government laboratories, primarily because the enormous cost of building these facilities could only be supported by government budgets. During this time, a few private companies managed to secure commercial rights to exploit the production capabilities of these facilities. Today, these companies and a few government agencies still provide the basis of global commercial radioisotope supply.

Fox, C.J.

1996-10-01

26

An alternate approach to the production of radioisotopes for nuclear medicine applications.  

PubMed

There is a growing need for the production of radioisotopes for both diagnostic and therapeutic medical applications. Radioisotopes that are produced using the (n,?) or (?,n) reactions, however, typically result in samples with low specific activity (radioactivity?gram) due to the high abundance of target material of the same element. One method to effectively remove the isotopic impurity is electro-magnetic mass separation. An Ion Source Test Facility has been constructed at TRIUMF to develop high-intensity, high-efficiency, reliable ion sources for purification of radioactive isotopes, particularly those used in nuclear medicine. In progress studies are presented. PMID:23556835

D'Auria, John M; Keller, Roderich; Ladouceur, Keith; Lapi, Suzanne E; Ruth, Thomas J; Schmor, Paul

2013-03-01

27

Possibilities for the production of radioisotopes for nuclear-medicine problems by means of photonuclear reactions  

SciTech Connect

For electrons of energy about 55 MeV that create an average current of about 40 Micro-Sign A, it is shown that the production of many of the radioisotopes important for nuclear medicine is possible in significant amounts.

Dzhilavyan, L. Z., E-mail: dzhil@cpc.inr.ac.ru [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Karev, A. I.; Raevsky, V. G. [Russian Academy of Sciences, Lebedev Institute of Physics (Russian Federation)

2011-12-15

28

Production and supply of radioisotopes with high-energy particle accelerators current status and future directions  

SciTech Connect

Although the production of radioisotopes in reactors or in low to medium energy cyclotrons appears to be relatively well established, especially for those isotopes that are routinely used and have a commercial market, certain isotopes can either be made only in high-energy particle accelerators or their production is more cost effective when made this way. These facilities are extremely expensive to build and operate, and isotope production is, in general, either not cost-effective or is in conflict with their primary mandate or missions which involve physics research. Isotope production using high-energy accelerators in the US, therefore, has been only an intermittent and parasitic activity. However, since a number of isotopes produced at higher energies are emerging as being potentially useful for medical and other applications, there is a renewed concern about their availability in a continuous and reliable fashion. In the US, in particular, the various aspects of the prediction and availability of radioisotopes from high-energy accelerators are presently undergoing a detailed scrutiny and review by various scientific and professional organizations as well as the Government. A number of new factors has complicated the supply/demand equation. These include considerations of cost versus needs, reliability factors, mission orientation, research and educational components, and commercial viability. This paper will focus on the present status and projected needs of radioisotope production with high-energy accelerators in the US, and will compare and examine the existing infrastructure in other countries for this purpose.

Srivastava, S.C.; Mausner, L.F.

1994-03-01

29

Boron  

MedlinePLUS

... who do not get much magnesium in their diet. Among younger women, the effect appears to be greater in women ... mg of boron per 2000 kcal per day. Diets considered to be low in boron provide ... pregnant or breast-feeding women over 19 years of age. For adolescents 14 ...

30

Using phosphogypsume and boron concentrator wastes in light brick production  

Microsoft Academic Search

In this study, use of wastes produced in phosphoric acid plants and boron concentrators in producing structural brick has been investigated. There are several parameters involved in using these wastes in brick production namely the rate of added waste, firing speed and firing temperature. The performance of these parameters can be measured by several criteria such as natural drying shortening,

Yüksel Abal?; Mehmet Ali Yurdusev; M. Sadrettin Zeybek; Ahmet Ali Kumanl?o?lu

2007-01-01

31

Fast flux test facility radioisotope production and medical applications  

SciTech Connect

The Fast Flux Test Facility (FFTF) is a 400-MW, sodium-cooled reactor that operated successfully from 1982 to 1992, conducting work in support of the liquid-metal reactor industry by developing and testing fuel assemblies, control rods, and other core reactor components. Upon termination of this program, the primary mission of FFTF ended, and it was placed in a standby mode in 1993. However, in January 1997 the U.S. Secretary of Energy requested that FFTF be evaluated for a future mission that would consist of a primary goal of producing tritium for nuclear defense applications and a secondary goal of supplying medical isotopes for research and clinical applications. Production by FFTF of tritium for U.S. nuclear weapons would augment the dual-track strategy now under consideration for providing a long-term tritium supply in the United States (consisting of a light water reactor option and an accelerator option). A decision by the Secretary of Energy on proceeding with steps leading toward the possible reactivation of FFTF will be made before the end of 1998.

Schenter, R.E.; Smith, S.G.; Tenforde, T.S. [Battelle-Pacific Northwest National Lab., Richland, WA (United States)

1997-12-01

32

Manipulation of in Vivo Sorbitol Production Alters Boron Uptake and Transport in Tobacco  

Microsoft Academic Search

Recent evidence that some species can retranslocate boron as complexes with sugar alcohols in the phloem suggests a possible mechanism for enhancing boron efficiency. We investigated the relationship between sugar alcohol (sorbitol) content, boron uptake and distribution, and translocation of foliar-applied, isotopically enriched 10B in three lines of tobacco (Nicotiana tabacum) plants differing in sorbitol production. In tobacco line S11,

Nacer Bellaloui; Patrick H. Brown; Abahaya M. Dandekar

1999-01-01

33

Production of boron-containing powder steels using master alloys and boron carbide  

Microsoft Academic Search

The properties of boron-containing structural powder steels produced using master alloys and boron carbide are examined. It\\u000a is established that sintered and thermally treated materials produced with master alloys show better mechanical properties\\u000a than those made with the use of boron carbide. The boron content of structural powder steels that promotes the optimum combination\\u000a of properties with the use of

G. A. Baglyuk; S. G. Napara-Volgina; L. N. Orlova; A. D. Kostenko; V. K. Kud

2011-01-01

34

ULTRASONIC AND RADIOGRAPHIC IMAGING OF NIOBIUM TARGET CAPSULES FOR RADIOISOTOPE PRODUCTION  

SciTech Connect

In the case of proton-irradiated radioisotope production, niobium target capsules containing gallium are exposed to intense radiation, thermally induced stress, for extended periods. The structural integrity of the target capsules is of crucial importance for containing the accelerator-produced radioisotopes and target material. The capsule window should be as thin and transparent to the proton beam as possible, and preferably should not become significantly activated under proton irradiation. In addition, the material for the capsule needs to be as defect-free as possible. Niobium encapsulated gallium targets have a history of unpredictable failure under intense irradiation with 100 MeV protons. This study illustrates the utility of non-destructive testing in order to detect defects that may result in mechanical failure of the capsules during irradiation. Prior to this work, it was not known if the gallium initially wets the niobium capsule that encapsulates it, and if it does, it is not known to what degree. However, the imaging techniques used in this work show that local areas of wetting do occur. We used ultrasonic images from various lots of niobium capsule material to assess the integrity of the capsules. Digital radiography is also used to detect any voids in the gallium that will tend to cause local heating in the capsules.

Bach, H. T.; Claytor, T. N.; Hunter, J. F.; Dozier, B. E.; Nortier, F. M.; Smith, D. M. [Los Alamos National Laboratory, MS J514, Los Alamos, NM 87545 (United States); Lenz, J. W. [John W. Lenz and Associates, 412 Muskingum Road, Waxahachie, TX 75165 (United States); Moddrell, C.; Smith, P. A. [P.A. Smith Concepts and Designs, 1475 Central Ave. Suite 250, Los Alamos, NM 87544 (United States)

2009-03-03

35

Production and purification of organic reagents labeled with radioisotopes produced by an accelerator  

Microsoft Academic Search

We studied the production of nine typical organic analytical reagents labeled with11C,13N and18F by irradiation with charged particles and bremsstrahlung and the purification of labeled compounds with HPLC and sublimation.\\u000a As a result, we found that six reagents, ?-naphthol, ?-naphthol, quinoline, ?-nitroso-?-naphthol, 8-hydroxyquinoline, and\\u000a 1,10-phenanthroline H2O could be labeled with11C by bombarding a mixture of each reagent and boron with

K. Shikano; K. Masumoto; T. Ohtsuki; M. Katoh

1999-01-01

36

Light Weight Radioisotopic Heater Unit (LWRHU) production for the Galileo Mission  

SciTech Connect

The Light Weight Radioisotopic Heater Unit (LWRHU) is a /sup 238/PuO/sub 2)minus/ fueled heat source designed to provide a thermal watt of power for space missions. The LWRHU will be used to maintain the temperature of various components on the spcaecraft at the required level. The heat source consists of a /sup 238/PuO/sub 2/ fuel pellet, a Pt-30Rh capsule, a pyrolytic graphite insulator, and a woven graphite aeroshell assembly. Los Alamos National Laboratory (LANL) has fabricated 134 heater units which will be used on the Galileo Mission. This report summarizes the specifications, fabrication processes, and production data for the heat sources fabricated at LANL. 4 figs., 15 tabs

Rinehart, G.H.

1988-04-01

37

Operational readiness review plan for the radioisotope thermoelectric generator materials production tasks  

SciTech Connect

In October 1989, a US shuttle lifted off from Cape Kennedy carrying the spacecraft Galileo on its mission to Jupiter. In November 1990, a second spacecraft, Ulysses, will be launched from Cape Kennedy with a mission to study the polar regions of the sun. The prime source of power for both spacecraft is a series of radioisotope thermoelectric generators (RTGs), which use plutonium oxide (plutonia) as a heat source. Several of the key components in this power system are required to ensure the safety of both the public and the environment and were manufactured at Oak Ridge National Laboratory (ORNL) in the 1980 to 1983 period. For these two missions, Martin Marietta Energy Systems, Inc. (Energy Systems), will provide an iridium-alloy component used to contain the plutonia heat source and a carbon-composite material that serves as a thermal insulator. ORNL alone will continue to fabricate the carbon-composite material. Because of the importance to DOE that Energy Systems deliver these high-quality components on time, performance of an Operational Readiness Review (ORR) of these manufacturing activities is necessary. Energy Systems Policy GP-24 entitled Operational Readiness Process'' describes the formal and comprehensive process by which appropriate Energy Systems activities are to be reviewed to ensure their readiness. This Energy System policy is aimed at reducing the risks associated with mission success and requires a management-approved readiness plan'' to be issued. This document is the readiness plan for the RTG materials production tasks. 6 refs., 11 figs., 1 tab.

Cooper, R.H.; Martin, M.M.; Riggs, C.R.; Beatty, R.L.; Ohriner, E.K.; Escher, R.N.

1990-04-19

38

Production of therapeutic radioisotopes in the ORNL High Flux Isotope Reactor (HFIR) for applications in nuclear medicine, oncologyand interventional cardiology  

Microsoft Academic Search

Summary  Greater availability of therapeutic radioisotopes is required to meet the demands for increasing clinical applications in nuclear medicine, oncology and interventional cardiology. Because of the need for very high specific activity products, methods other than direct neutron capture reactions (n,?-elastic and n,n’-inelastic routes) are required to insure that the highest specific activity - and hopefully no carrier added (nca) -

S. Mirzadeh; A. L. Beets; M. Du

2005-01-01

39

Improved Techniques Used at Brookhaven National Laboratory to Package and Dispose of Radioisotope Production Waste Lowers Worker Exposure  

SciTech Connect

This paper describes the operations that generate Radioisotope Production Waste at Brookhaven National Laboratory (BNL) and the improved techniques used to handle and dispose of this waste. Historically, these wastes have produced high worker exposure during processing, packaging and disposal. The waste is made up of accelerator-produced nuclides of short to mid-length half-lives with a few longer-lived nuclides. However, because radiopharmaceutical research and treatment requires a constant supply of radioisotopes, the waste must be processed and disposed of in a timely manner. Since the waste cannot be stored for long periods of time to allow for adequate decay, engineering processes were implemented to safely handle the waste routinely and with ALARA principles in mind.

Sullivan, P.

2003-02-24

40

Boron  

SciTech Connect

This paper reports that borate minerals and refined borates are used extensively for the manufacture of vitreous materials such as insulation and textile fiberglasses, borosilicate glass, and porcelain enamels and frits. In North America, these applications are estimated to account for over 54% of the borate consumption. Other substantial uses are in soaps and detergents, metallurgy, fire retardants, industrial biocides, agriculture, and various miscellaneous applications. Reported domestic borate consumption in 1990 was estimated by the U.S. Bureau of Mines to be 320 000 metric tons B{sub 2}O{sub 3} versus 354 000 metric tons B{sub 2}O{sub 3} in 1989. Consumption is projected to remain essentially static in 1991. Imports were estimated by the Bureau to be 50 000 metric tons B{sub 2}O{sub 3} in 1990. Exports of boric acid and refined borates were approximately 650 000 metric tons of product, a 15 000 metric ton increase from the 1989 level. This increase partially offsets the drop in the 1990 consumption level.

Cozen, L.F. (United States Borax and Chemical Corp., Los Angeles, CA (US))

1991-05-01

41

PRODUCTION OF RADIOISOTOPES OF NIOBIUM BY IRRADIATION OF ZIRCONIUM WITH PROTONS  

Microsoft Academic Search

For the purpose of obtaining neutron-deficient radioisotopes of niobium ; to be used for the study of decay scheme and for carrier-free tracer, separation ; of niobium from irradiated zirconium was examined by solvent extraction and radio-; colloid formation. Extraction of niobium fluoride with methyl-iso-butyl ketone ; was successful, but the extraction was retarded in the absence of carrier. ;

K. Saito; S. Suzuki; M. Saito

1963-01-01

42

Production of medical radioisotopes with high specific activity in photonuclear reactions with ?-beams of high intensity and large brilliance  

NASA Astrophysics Data System (ADS)

We study the production of radioisotopes for nuclear medicine in ( ?, xn+ yp) photonuclear reactions or ( ?, ?') photoexcitation reactions with high-flux [(1013-1015) ?/s], small diameter ˜(100 ?m)2 and small bandwidth (? E/ E?10-3-10-4) ? beams produced by Compton back-scattering of laser light from relativistic brilliant electron beams. We compare them to (ion, xn+ yp) reactions with (ion = p,d, ?) from particle accelerators like cyclotrons and (n, ?) or (n,f) reactions from nuclear reactors. For photonuclear reactions with a narrow ?-beam the energy deposition in the target can be managed by using a stack of thin target foils or wires, hence avoiding direct stopping of the Compton and pair electrons (positrons). However, for ions with a strong atomic stopping only a fraction of less than 10-2 leads to nuclear reactions resulting in a target heating, which is at least 105 times larger per produced radioactive ion and often limits the achievable activity. In photonuclear reactions the well defined initial excitation energy of the compound nucleus leads to a small number of reaction channels and enables new combinations of target isotope and final radioisotope. The narrow bandwidth ? excitation may make use of the fine structure of the Pygmy Dipole Resonance (PDR) or fluctuations in ?-width leading to increased cross sections. Within a rather short period compared to the isotopic half-life, a target area of the order of (100 ?m)2 can be highly transmuted, resulting in a very high specific activity. ( ?, ?') isomer production via specially selected ? cascades allows to produce high specific activity in multiple excitations, where no back-pumping of the isomer to the ground state occurs. We discuss in detail many specific radioisotopes for diagnostics and therapy applications. Photonuclear reactions with ?-beams allow to produce certain radioisotopes, e.g. 47Sc, 44Ti, 67Cu, 103Pd, 117 m Sn, 169Er, 195 m Pt or 225Ac, with higher specific activity and/or more economically than with classical methods. This will open the door for completely new clinical applications of radioisotopes. For example 195 m Pt could be used to verify the patient's response to chemotherapy with platinum compounds before a complete treatment is performed. Also innovative isotopes like 47Sc, 67Cu and 225Ac could be produced for the first time in sufficient quantities for large-scale application in targeted radionuclide therapy.

Habs, D.; Köster, U.

2011-05-01

43

Production of medical radioisotopes in the ORNL High Flux Isotope Reactor (HFIR) for cancer treatment and arterial restenosis therapy after PTCA  

SciTech Connect

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) represents an important resource for the production of a wide variety of medical radioisotopes. In addition to serving as a key production site for californium-252 and other transuranic elements, important examples of therapeutic radioisotopes which are currently routinely produced in the HFIR for distribution include dysprosium-166 (parent of holmium-166), rhenium-186, tin-117m and tungsten-188 (parent of rhenium-188). The nine hydraulic tube (HT) positions in the central high flux region permit the insertion and removal of targets at any time during the operating cycle and have traditionally represented a major site for production of medical radioisotopes. To increase the irradiation capabilities of the HFIR, special target holders have recently been designed and fabricated which will be installed in the six Peripheral Target Positions (PTP), which are also located in the high flux region. These positions are only accessible during reactor refueling and will be used for long-term irradiations, such as required for the production of tin-117m and tungsten-188. Each of the PTP tubes will be capable of housing a maximum of eight HT targets, thus increasing the total maximum number of HT targets from the current nine, to a total of 57. In this paper the therapeutic use of reactor-produced radioisotopes for bone pain palliation and vascular brachytherapy and the therapeutic medical radioisotope production capabilities of the ORNL HFIR are briefly discussed.

Knapp, F.F. Jr.; Beets, A.L.; Mirzadeh, S.; Alexander, C.W.; Hobbs, R.L.

1998-06-01

44

Light weight radioisotope heater unit (LWRHU) production for the Cassini mission  

SciTech Connect

The Light-Weight Radioisotope Heater Unit (LWRHU) is a [sup 238]PuO[sub 2] fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. The heat sources are required to maintain the temperature of specific components within normal operating ranges. The heat source consists of a hot- pressed [sup 238]PuO[sub 2] fuel pellet, a Pt-3ORh vented capsule, a pyrolytic graphite insulator, and a woven graphite aeroshell assembly. Los Alamos National Laboratory has fabricated 180 heat sources, 157 of which will be used on the Cassini mission.

Rinehart, G.H.

1997-01-01

45

Use of boron waste as a fluxing agent in production of red mud brick  

Microsoft Academic Search

The study was directed towards determining the usability of clay and fine wastes (CW and FW) of boron from the concentrator plant in Kirka (Turkey) as a fluxing agent in production of red mud (RM) brick. Both laboratory studies on the characterization of materials and industrial-scale tests for production of bricks were carried out. CW and FW, which have similar

Taner Kavas

2006-01-01

46

Annual Technical Progress Report of Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2006 Through September 30, 2007  

SciTech Connect

The Office of Radioisotope Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Radioisotope Power Systems for fiscal year (FY) 2007. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

King, James F [ORNL

2008-04-01

47

Masters Thesis- Criticality Alarm System Design Guide with Accompanying Alarm System Development for the Radioisotope Production Laboratory in Richland, Washington  

SciTech Connect

A detailed instructional manual was created to guide criticality safety engineers through the process of designing a criticality alarm system (CAS) for Department of Energy (DOE) hazard class 1 and 2 facilities. Regulatory and technical requirements were both addressed. A list of design tasks and technical subtasks are thoroughly analyzed to provide concise direction for how to complete the analysis. An example of the application of the design methodology, the Criticality Alarm System developed for the Radioisotope Production Laboratory (RPL) of Richland, Washington is also included. The analysis for RPL utilizes the Monte Carlo code MCNP5 for establishing detector coverage in the facility. Significant improvements to the existing CAS were made that increase the reliability, transparency, and coverage of the system.

Greenfield, Bryce A.

2009-12-20

48

Characterization of electrodeposited elemental boron  

Microsoft Academic Search

Elemental boron was produced through electrowinning from potassium fluoroborate dissolved in a mixture of molten potassium fluoride and potassium chloride. The characteristics of the electrodeposited boron (raw boron) as well as the water and acid-leached product (processed boron) were studied. The chemical purity, specific surface area, size distribution of particles and X-ray crystallite size of the boron powders were investigated.

Ashish Jain; S. Anthonysamy; K. Ananthasivan; R. Ranganathan; Vinit Mittal; S. V. Narasimhan; P. R. Vasudeva Rao

2008-01-01

49

Boron in Very Metal-Poor Stars: Production of Light Elements in the Early Galaxy  

NASA Astrophysics Data System (ADS)

We propose to derive the boron abundances in two very metal- deficient stars (-2.4>=[Fe/H]>=-2.9) by observing the B I 2496.7 A line with the G270M/SSA configuration. The abundances will be computed under NLTE conditions. Both stars have also accurate determinations of lithium (including 6Li for one of them), beryllium and oxygen abundances, which will allow us to compute and interpret the abundance ratios between these elements. The available data for the star HD140283 ([Fe/H]=-2.7), for which an accurate NLTE boron abundance has been derived, seem to favour the hypothesis that boron and beryllium in Population II stars were produced by cosmic ray induced spallation reactions and not by inhomogeneous big bang nucleosynthesis. These new observations, which include what is probably the most metal-poor unevolved star known for which boron can be measured with HST, together with the results obtained for HD140283, will be the most useful diagnostic used up to now to precisely constrain the different mechanisms proposed as responsible for the light element production in the early Galaxy.

Lopez, Ramon

1995-07-01

50

Influence of oxygen on defect production in electron-irradiated, boron-doped silicon  

NASA Astrophysics Data System (ADS)

Deep level transient spectroscopy (DLTS) measurements were made on float-zone and crucible-grown, boron-doped silicon irradiated with 1-MeV electrons. The minority carrier trap attributed to a boron-related state, was not seen in low-resistivity, float-zone silicon. However, a new majority carrier trap was observed in these samples. In the case of more lightly doped material the minority carrier trap was present, and its introduction rate was lower in float-zone than in crucible-grown silicon. For 1- and 10-ohm-cm float-zone material that was oxidized during processing, the introduction rates for this trap were comparable to those for crucible-grown silicon. This behavior indicates that the minority carrier trap involves oxygen and that it may be due to a boron-oxygen complex. The majority carrier trap seen in heavily doped, float-zone silicon may also involve boron but not oxygen. Observed trap concentrations suggest that oxygen content in the regions examined by DLTS is affected by processing techniques. Other differences were observed in defect production and annealing behavior of electron-irradiated, float-zone and crucible-grown silicon.

Deangelis, H. M.; Drevinsky, P. J.

51

FOLIAR BORON ENHANCES LEAF CHLOROSIS AND DOES NOT AFFECT PECAN PRODUCTION AND NUT QUALITY  

Microsoft Academic Search

The narrow range between boron (B) deficiency and toxicity compared with other micronutrients is a serious problem for sustainable production of pecan throughout the southwest United States of America. However, performance of pecan under foliar B is lacking. Five B treatments (0, 0.5, 1.0, 1.5 kg B ha, water spray) were applied to 27 years old trees of pecan variety

Shad Khan Khalil; John Mexal; Abdur Rehman; Amanullah; Fida Muhammad; Amir Zaman Khan

2011-01-01

52

Boron as an Alternate Engine Fuel  

Microsoft Academic Search

Boron fuel is made up of the element boron. Boron as a chemical fuel will be a promising engine fuel in the future. Cars in which boron fuel simply burns will be true zero emission vehicles. Total world production of boron minerals was approximately 4,270,000 tons in 2000. Turkey has the largest boron sources in the world. It is estimated

M. Balat

2007-01-01

53

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Tasks for October 1, 2003 through September 30, 2004  

SciTech Connect

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2004. Production and production maintenance activities for flight quality (FQ) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. In all three cases, production maintenance is assured by the manufacture of limited quantities of FQ components. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

None listed

2005-06-01

54

The in situ production of radioisotopes in rock matrices with particular reference to the Stripa granite  

SciTech Connect

The in situ production of {sup 3}H, {sup 14}C, {sup 36}Cl, {sup 129}I, {sup 37}Ar, {sup 39}Ar, {sup 81}Kr and {sup 85}Kr by neutron-induced reactions and spontaneous nuclear decay processes has been estimated within the Stripa granite, its associated fracture minerals and surrounding leptite. Experimental measurements of the neutron flux within the Stripa granite are within 15% of theoretical values and have been used to calculate neutron-induced production rates. Activities of radionuclides that may enter ground waters from the rock matrix are discussed in relation to their initial distribution in the host rock and their subsequent release into solution. The measured radioactivities in ground waters from the high radioelement-content granites at Stripa are compared with estimates of their in situ production within the granite and of their solution by fracture-borne fluids. The activities of {sup 3}H and {sup 14}C which enter fracture fluids from the rock matrix are close to present detection limits. For {sup 3}H, the most significant production is within the rock matrix whilst for {sup 14}C it is within the circulating fracture fluids. Chlorine-36 production by neutron-capture within the granite is much more significant than inputs from cosmogenic and nuclear fallout sources. The {sup 36}Cl/Cl ratio may be used to evaluate Cl{sup minus} sources in saline ground waters. In situ production of {sup 129}I by spontaneous fission of {sup 238}U is an important source of {sup 129}I in the high radioactivity Stripa granite. Argon-37, {sup 39}Ar and {sup 85}Kr are produced by in situ reactions within the rock matrix, fracture mineralization and at the sites of U-mineralization, respectively. The use of some cosmogenic radionuclides for the estimation of groundwater residence times may be limited because of in situ production.

Andrews, J.N.; Smith, B. (Univ. of Bath (England)); Davis, S.N.; Fabryka-Martin, J. (Univ. of Arizona, Tucson (USA)); Fontes, J.Ch.; Michelot, J.L. (Universite de Paris-Sud, Orsay (France)); Lehmann, B.E.; Loosli, H.H. (Physikalisches Institut der Universitaet Bern (Switzerland)); Moser, H.; Wolf, M. (Institut fur Radiohydrometrie, Neuherberg (West Germany))

1989-08-01

55

Dual-Label Radioisotope Method for Simultaneously Measuring Bacterial Production and Metabolism in Natural Waters †  

PubMed Central

Bacterial production and amino acid metabolism in aquatic systems can be estimated by simultaneous incubation of water samples with both tritiated methyl-thymidine and 14C-labeled amino acids. This dual-label method not only saves time, labor, and materials, but also allows determination of these two parameters in the same microbial subcommunity. Both organic carbon incorporation and respiration can be estimated. The results obtained with the dual-label technique are not significantly different from single-radiolabel methods over a wide range of bacterial activity. The method is particularly suitable for large-scale field programs and has been used successfully with eutrophic estuarine samples as well as with oligotrophic oceanic water. In the mesohaline portion of Chesapeake Bay, thymidine incorporation ranged seasonally from 2 to 635 pmol liter?1 h?1 and amino acid turnover rates ranged from 0.01 to 28.4% h?1. Comparison of thymidine incorporation with amino acid turnover measurements made at a deep, midbay station in 1985 suggested a close coupling between bacterial production and amino acid metabolism during most of the year. However, production-specific amino acid turnover rates increased dramatically in deep bay waters during the spring phytoplankton bloom, indicating transient decoupling of bacterial production from metabolism. Ecological features such as this are readily detectable with the dual-label method.

Jonas, Robert B.; Tuttle, Jon H.; Stoner, Daphne L.; Ducklow, Hugh W.

1988-01-01

56

The in situ production of radioisotopes in rock matrices with particular reference to the Stripa granite  

Microsoft Academic Search

The in situ production of 3 H, 14 C, 36 Cl, 129 I, 37 Ar, 39 Ar, 81 Kr and 85 Kr by neutron-induced reactions and spontaneous nuclear decay processes has been estimated within the Stripa granite, its associated fracture minerals and surrounding leptite. Experimental measurements of the neutron flux within the Stripa granite are within 15% of theoretical values

J. N. Andrews; S. N. Davis; J. Fabryka-Martin; B. E. Lehmann; H. H. Loosli; J.-L. Michelot; H. Moser; B. Smith; M. Wolf

1989-01-01

57

Five Years of Cyclotron Radioisotope Production Experiences at the First PET-CT in Venezuela  

NASA Astrophysics Data System (ADS)

Five years operation of a compact cyclotron installed at PET-CT facility in Caracas, Venezuela is given. Production rate of 18F labeled FDG, operation and radiation monitoring experience are included. We conclude that 18FDG CT-PET is the most effective technique for patient diagnosis.

Colmenter, L.; Sajo-Bohus, L.; Liendo, J. A.; Greaves, E. D.; Coelho, D.; Barros, H.; Castillo, J.; Esteves, L. M.; Ruiz, N.; Morales, L.; Lugo, I.

2007-10-01

58

Production of carrier-free scandium radioisotopes from a neutron-irradiated potassium titanium oxalate target  

Microsoft Academic Search

Summary Extraction of scandium and calcium radioactivities with 1% HDEHP in benzene from nitric acid solution was investigated. The effect of potassium titanium oxalate concentration on the extraction from 1.5M nitric acid was studied. From the data obtained, two procedures based on batch solvent extraction and extraction chromatography were developed for separation and production of radioscandium from a neutron-irradiated potassium

Hisham F. Aly; Mohammed A. El-Haggan

1971-01-01

59

Feasibility study for production of I-131 radioisotope using MNSR research reactor.  

PubMed

A feasibility study for (131)I production using a Low Power Research Reactor was conducted to predict the yield of (131)I by cyclic activation technique. A maximum activity of 5.1GBq was achieved through simulation using FORTRAN 90, for an irradiation of 6h. But experimentally only 4h irradiation could be done, which resulted in an activity of 4.0×10(5)Bq. The discrepancy in the activities was due to the fact that beta decays released during the process could not be considered. PMID:21900016

Elom Achoribo, A S; Akaho, Edward H K; Nyarko, Benjamin J B; Osae Shiloh, K D; Odame Duodu, Godfred; Gibrilla, Abass

2011-08-23

60

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technical Program Tasks for October 1, 2005 through September 30, 2006  

SciTech Connect

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

None

2007-04-02

61

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Tasks for October 1, 2004 through September 30, 2005  

SciTech Connect

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2005. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

None listed

2006-08-03

62

ANNUAL TECHNICAL PROGRESS REPORT OF RADIOISOTOPE POWER SYSTEMS MATERIALS PRODUCTION AND TECHNOLOGY PROGRAM TASKS FOR OCTOBER 1, 2010 THROUGH SEPTEMBER 30, 2011  

SciTech Connect

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration (NASA) for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, the Oak Ridge National Laboratory (ORNL) produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. These components were also produced for the Pluto New Horizons and Mars Science Lab missions launched in January 2006 and November 2011respectively. The ORNL has been involved in developing materials and technology and producing components for the DOE for nearly four decades. This report reflects program guidance from the Office of RPS for fiscal year (FY) 2011. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new RPS. Work has also been initiated to establish fabrication capabilities for the Light Weight Radioisotope Heater Units.

King, James F [ORNL

2012-05-01

63

Radioisotope research, production, and processing at the University of Missouri Research Reactor  

SciTech Connect

The University of Missouri Research Reactor (MURR) is a 10 MW, light-water-cooled and moderated research reactor which first achieved criticality in 1996 and is currently the highest powered university-owned research reactor in the U.S. For many years a major supplier of reactor-produced isotopes for research and commercial purposes, in the last 15 years MURR has concentrated on development of reactor-produced beta-particle emitters for experimental use in nuclear medicine therapy of cancer and rheumatoid arthritis. MURR has played a major role in the development of bone cancer pain palliation with the agents {sup 153}Sm EDTMP and {sup 186}Re/{sup 188}Re HEDP, as well as in the use of {sup 186}Re, {sup 177}Lu, {sup 166}Ho, and {sup 105}Rh for radioimmunotherapy and receptor-agent-guided radiotherapy. MURR is also responsible for the development of therapeutic, {sup 90}Y-labeled glass microspheres for the treatment of liver tumors, a product ({sup 90}Y Therasphere{trademark}) which is currently an approved drug in Canada. MURR has also pioneered the development of {sup 188}W/{sup 188}Re and {sup 99}Mo/{sup 99m}Tc gel generators, which make the use of low specific activity {sup 188}W and {sup 99}Mo practical for such isotope generators.

Ehrhardt, G.J.; Ketring, A.R.; Ja, Wei; Ma, D.; Zinn, K.; Lanigan, J.

1995-12-31

64

Production of Lithium, Beryllium and Boron in Supernova Ejecta  

NASA Astrophysics Data System (ADS)

We model the nucleosynthesis of light elements (Li,Be,B) by spallation of C,N,O targets by accelerated H,He in expanding supernova ejecta. Recent observations of metal-poor halo dwarfs indicate that these light element abundance increases linearly with metalicity, i.e. the ratio of these elements to iron is constant. The model of formation of these elements in interstellar medium where spallation takes place by galactic cosmic rays colliding with interstellar matter would not give a linear dependence of spallation products with iron abundance. We investigate the scenario of formation of these elements in expanding supernova where spallation would take place in an unmixed medium of supernova ejecta, which would give the observed linear dependence. Calculations will be presented on energetics of this scenario and abundances and ratios of the isotopes of Li,Be,B.

Majmudar, Deepa

1995-12-01

65

List of DOE radioisotope customers with summary of radioisotope shipments, FY 1983  

SciTech Connect

This document lists DOE's radioisotope production and distribution activities by its facilities at Argonne National Laboratory; Pacific Northwest Laboratory; Idaho Operations Office; Los Alamos National Laboratory; Oak Ridge National Laboratory; Savannah River Plant; and UNC Nuclear Industries, Inc. The information is divided into five sections: isotope suppliers, facility contacts, and isotopes or services supplied; lists of customers, suppliers and isotopes purchased; list of isotopes purchased cross-referenced to customer codes; geographic locations of radioisotope customers; and radioisotope sales and transfers - FY 1983.

Baker, D.A.

1984-08-01

66

RADIOISOTOPES AS SOURCES OF HEAT  

Microsoft Academic Search

The thermal power generated from beta- emitting and alpha- emitting ; radioisotopes is compared with various transuranic elements which decay by ; spontaneous fission. The production of the transuranic isotopes is reviewed with ; particular attention given to the build-up of various transuranic isotopes that ; would offer useful power generation by their own decay. Comparison of the decay ;

1960-01-01

67

PRODUCTION OF DIBORANE BY REDUCING BORON FLUORIDE ETHYL ETHERATE WITH CALCIUM HYDRIDE  

Microsoft Academic Search

Boron trifluoride reduction by calcium hydride was analyzed as a new ; method for obtaining boron and calcium boride. The purpose of the experiment was ; to produce diborane by reducing boron trifluoride etherate by calcium hydride. ; Synthesis of diborane was achieved at temperatures near the etherate boiling ; point. Tabulated data show good yields of diborane. (R.V.J.);

V. I. Mikheeva; E. M. Fedneva; V. I. Alpatova

1960-01-01

68

Radioisotope Sources of Electric Power.  

National Technical Information Service (NTIS)

The basic principles of operation of radioisotope current sources for various purposes are summarized. Structural diagrams of contemporary radioisotope thermoelectric generators are surveyed. Methods of obtaining radioisotope sources of thermal energy are...

G. M. Fradkin V. M. Kodyukov

1973-01-01

69

Annual Technical Progress Report of the Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2008 through September 30, 2009  

SciTech Connect

The Office of Space and Defense Power Systems of the U. S. Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators (RTG) were supplied by the DOE to the National Aeronautics and Space Administration (NASA) for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, the Oak Ridge National Laboratory (ORNL) produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. ORNL has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2009. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new RPS.

King, James F [ORNL

2010-05-01

70

Annual Technical Progress Report of Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2007 Through September 30,2008  

SciTech Connect

The Office of Radioisotope Power Systems (RPS) of the Department of Energy (DOE) provides RPS for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration (NASA) for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of RPS for fiscal year (FY) 2008. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new RPS.

King, James F [ORNL

2009-04-01

71

Method for separating boron isotopes  

DOEpatents

A method of separating boron isotopes .sup.10 B and .sup.11 B by laser-induced selective excitation and photodissociation of BCl.sub.3 molecules containing a particular boron isotope. The photodissociation products react with an appropriate chemical scavenger and the reaction products may readily be separated from undissociated BCl.sub.3, thus effecting the desired separation of the boron isotopes.

Rockwood, Stephen D. (Los Alamos, NM)

1978-01-01

72

Radioisotopic heat sources. Revision 1  

Microsoft Academic Search

For the radioisotopes with half-lives over a year, only eight appear to be obtainable in the foreseeable future. The fission products, strontium-90, cesium-137, and promethium-147, exist in wastes from reactor processing, diluted with enormous volumes of other elements and salts. Among those isotopes producible by irradiation of special target materials (cobalt-60, uranium-232, plutonium-238, and curium-244) cobalt-60, though easy to produce,

Rohrmann

1963-01-01

73

Effect of corrosion products (neodymium iron boron) on oral fibroblast proliferation.  

PubMed

The biological effects of the corrosion products of neodymium iron boron (Nd2Fe14B) magnets are largely unknown. The aim of this study was to identify the types of corrosion product and to evaluate the effect of the corrosion products (CP) of Nd2Fe14B magnets on the proliferation of human oral mucosal fibroblasts. Uncoated Nd2Fe14B magnets were stored in saline at 37 degrees C for 6 months and the corrosion products collected. 100 microL of a cell suspension (human oral mucosal fibroblasts [14 x 10(4) cells/mL]) was aliquoted into 72 wells of a 96-well plate, the remaining plates receiving culture medium only. After 12 h incubation at 37 degrees C, each well then received 100 microL of either (A) culture medium, (B) 100% CP, (C) 50% CP, or (D) 0% CP. The plates were reincubated at 37 degrees C for a further 48, 96, or 144 h. Fibroblast proliferation was assessed using the methylene blue uptake/elution technique. The compounds in the corrosion product were examined using quantitative X-ray analysis. Statistical analysis (ANOVA, Bonferroni's test 0.05, SAS v 6.04), showed that at each time point, the cell numbers in groups B, C, and D were significantly lower than group A. Within groups B, C, and D no significant differences were found, despite the suggestion of a dose response effect. Fibroblast proliferation in the presence of corrosion products was significantly lower than with culture medium. Fibroblast proliferation did occur in the presence of 0, 50, and 100% CP. The actual corrosion products appeared to be salts of iron but 3.2% (+/- 0.6) of neodymium chloride (NdCl3) was found. PMID:7492811

Evans, R D; McDonald, F

1995-01-01

74

Process for making boron nitride using sodium cyanide and boron  

DOEpatents

This a very simple process for making boron nitride by mixing sodium cyanide and boron phosphate and heating the mixture in an inert atmosphere until a reaction takes place. The product is a white powder of boron nitride that can be used in applications that require compounds that are stable at high temperatures and that exhibit high electrical resistance.

Bamberger, Carlos E. (Oak Ridge, TN)

1990-01-01

75

Green Approach--Multicomponent Production of Boron--Containing Hantzsch and Biginelli Esters  

PubMed Central

Multicomponent reactions are excellent methods that meet the requirements of green chemistry, by reducing the number of steps, and consequently reducing purification requirements. Accordingly, in this work, 11 novel hybrid-boron-containing molecules, namely eight 1,4-dihydropyridines and three 3,4-dihydropyrimidinones, derived from formylphenylboronic acids (ortho, meta and para), were obtained using a green approach, involving H-4CR and B-3CR practices, in the presence of ethanol, which is a green solvent, and using three comparatively different modes of activation (mantle heating, yield 3%–7% in 24 h, Infrared Radiation (IR) irradiation, yield 12%–17% in 12 h, and microwave irradiation, yield 18%–80%, requiring very low reaction times of 0.25–0.33 h). In addition, as a green-approach is offered, a convenient analysis, of the 12 green chemistry principles for the overall procedure was performed. Finally, since all the products are new, characterizations were carried out using common analytic procedures (1H, 11B, and 13C NMR, FAB+MS, HRMS, and IR). The accurate mass data of unexpected ions related to interactions between thioglycerol and the expected products, in the FAB+-mode, enabled unequivocal characterization of the target molecules.

Martinez, Joel; Romero-Vega, Stephany; Abeja-Cruz, Rita; Alvarez-Toledano, Cecilio; Miranda, Rene

2013-01-01

76

Minerals Yearbook 1989: Boron  

Microsoft Academic Search

U.S. production and sales of boron minerals and chemicals decreased during the year. Domestically, glass fiber insulation was the largest use for borates, followed by sales to distributors, textile-grade glass fibers, and borosilicate glasses. California was the only domestic source of boron minerals. The United States continued to provide essentially all of its own supply while maintaining a strong position

Lyday

1990-01-01

77

Increased abundance of proteins involved in phytosiderophore production in boron-tolerant barley.  

PubMed

Boron (B) phytotoxicity affects cereal-growing regions worldwide. Although B-tolerant barley (Hordeum vulgare) germplasm is available, molecules responsible for this tolerance mechanism have not been defined. We describe and use a new comparative proteomic technique, iTRAQ peptide tagging (iTRAQ), to compare the abundances of proteins from B-tolerant and -intolerant barley plants from a 'Clipper' x 'Sahara' doubled-haploid population selected on the basis of a presence or absence of two B-tolerance quantitative trait loci. iTRAQ was used to identify three enzymes involved in siderophore production (Iron Deficiency Sensitive2 [IDS2], IDS3, and a methylthio-ribose kinase) as being elevated in abundance in the B-tolerant plants. Following from this result, we report a potential link between iron, B, and the siderophore hydroxymugineic acid. We believe that this study highlights the potency of the iTRAQ approach to better understand mechanisms of abiotic stress tolerance in cereals, particularly when applied in conjunction with bulked segregant analysis. PMID:17478636

Patterson, John; Ford, Kris; Cassin, Andrew; Natera, Siria; Bacic, Antony

2007-05-03

78

Development of Next Generation Segmented Thermoelectric Radioisotope Power Systems  

Microsoft Academic Search

Radioisotope thermoelectric generators have been used for space-based applications since 1961 with a total of 22 space missions that have successfully used RTGs for electrical power production. The key advantages of radioisotope thermoelectric generators (RTGs) are their long life, robustness, compact size, and high reliability. Thermoelectric converters are easily scalable, and possess a linear current-voltage curve, making power generation easy

J. Fleurial; T. Caillat; R. C. Ewell

2005-01-01

79

Magnetron sputtered boron films  

DOEpatents

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence. 8 figs.

Makowiecki, D.M.; Jankowski, A.F.

1998-06-16

80

Magnetron sputtered boron films  

DOEpatents

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence.

Makowiecki, Daniel M. (Livermore, CA); Jankowski, Alan F. (Livermore, CA)

1998-01-01

81

Minerals Yearbook 1989: Boron.  

National Technical Information Service (NTIS)

U.S. production and sales of boron minerals and chemicals decreased during the year. Domestically, glass fiber insulation was the largest use for borates, followed by sales to distributors, textile-grade glass fibers, and borosilicate glasses. California ...

P. A. Lyday

1990-01-01

82

Minerals Yearbook 1990: Boron.  

National Technical Information Service (NTIS)

U.S. production and sales of boron minerals and chemicals increased during the year. Domestically, glass fiber insulation was the largest use for borates, followed by sales to distributors, textile-grade glass fibers, and borosilicate glasses. California ...

P. A. Lyday

1991-01-01

83

Minerals Yearbook, 1993: Boron.  

National Technical Information Service (NTIS)

U.S. production and sales of boron minerals and chemicals increased during the year. Domestically, glass fiber insulation was the largest use for borates, followed by sales to borosilicate glass, textile-grade glass fibers, and agriculture. California was...

P. A. Lyday

1994-01-01

84

List of DOE radioisotope customers with summary of radioisotope shipments, FY 1980  

SciTech Connect

The sixteenth edition of the radioisotope customer list was prepared at the request of the Office of Health and Environmental Research, Office of energy Research, Department of Energy (DOE). This document lists DOE's radioisotope production and distribution activities by its facilities at Argonne National Laboratory; Pacific Northwest Laboratory; Brookhaven National Laboraory; Hanford Engineering Development Laboratory; Idaho Operations Office; Los Alamos Scientific Laboratory; Mound Facility; Oak Ridge National Laboratory; Savannah River Laboratory; and UNC Nuclear Industries, Inc. The information is divided into five sections: (1) isotope suppliers, facility, contracts and isotopes or services supplied; (2) alphabetical list of customers, and isotopes purchased; (3) alphabetical list of isotopes cross-referenced to customer numbers; (4) geographical location of radioisotope customers; and (5) radioisotope sales and transfers-FY 1980.

Burlison, J.S. (comp.)

1981-08-01

85

List of DOE radioisotope customers with summary of radioisotope shipments, FY 1981  

SciTech Connect

The seventeenth edition of the radioisotope customer list was prepared at the request of the Office of Health and Environmental Research, Office of Energy Research, Department of Energy (DOE). This document lists DOE's radioisotope production and distribution activities by its facilities at Argonne National Laboratory: Pacific Northwest Laboratory; Brookhaven National Laboratory; Hanford Engineering Development Laboratory; Idaho Operations Office; Los Alamos Scientific Laboratory; Mound Facility; Oak Ridge National Laboratory; Savannah River Laboratory; and UNC Nuclear Industries, Inc. The information is divided into five sections: (1) isotope suppliers, facility, contracts and isotopes or services supplied; (2) alphabetical list of customers, and isotopes purchased; (3) alphabetical list of isotopes cross-referenced to customer numbers; (4) geographical location of radioisotope customers; and (5) radioisotope sales and transfers-FY 1980.

Burlison, J.S. (comp.)

1982-09-01

86

Minerals Yearbook, 1988. Boron  

SciTech Connect

U.S. production and sales of boron minerals and chemicals decreased during the year. Glass-fiber insulation was the largest use for borates, followed by sales to distributors, textile-grade glass fibers, and borosilicate glasses. California was the only domestic source of boron minerals. The report discusses the following: domestic data coverage; legislation and government programs; domestic production; comsumption and uses; prices; foreign trade; world capacity; world review--Argentina, Chile, France, Italy, Turkey, United Kingdom; Technology.

Lyday, P.A.

1988-01-01

87

Neutron Detector Shielding Using Boron and Water  

NASA Astrophysics Data System (ADS)

There has always been a need to develop better shielding for particle detectors from background radiation. With the development of DUSEL (Deep Underground Science and Engineering Laboratory at Homestake), new opportunities exist to make measurements away from the surface cosmic radiation. Doing measurements underground, coupled with better shielding, allows measurements of reactions that are too weak to observe otherwise. Underground, we can take advantage of thousands of meters of rock to shield detectors from cosmic background radiation. Even this rock can be insufficient, as a naturally occurring radioisotopes found in the rock can yield many kinds of radiation, such as gamma rays, beta rays, alpha particles, neutrons, and other fission products. We are designing and testing a shield made for our proportional neutron detectors made of boron and water. Water is used to slow down, or thermalize, the neutrons. Boron is in turn used to capture the incoming neutrons, due to its large neutron capture cross section. This shield was tested and the data has been analyzed, showing that we can achieve a factor of 63 reduction in the number of neutrons detected. We will also scale down this design so that it can provide background protection to detectors in the Nuclear Structure Laboratory at the University of Notre Dame.

Jung, Frederick; Best, Andreas; Aprahamian, Ani; Wiescher, Michael

2010-11-01

88

Diamond and cubic boron nitride composites with a metallic binder: Their production and application  

Microsoft Academic Search

relative to various solid bodies is due to the formation at the interface of bonds, the energy of which is comparable with the liquid phase surface energy and which can only be achieved via interatomic chemical forces during the chemical reaction. When a solid nonmetallic substance (e.g., diamond) or a compound (material based on cubic boron nitride) is wetted with

Yu. V. Naidich; I. A. Lavrinenko; G. A. Kolesnichenko; G. P. Volk; V. P. Umanskii

1993-01-01

89

Radioisotope thermoelectric generators for implanted pacemakers  

SciTech Connect

This paper discusses the development and application of long-life lithium batteries and the problems associated with miniature radioisotope thermoelectric generators (RITEG) with service lives of 10 years or longer. On eof the main problems encountered when devising a radioisotope heat source (RHS) for an RITEG is to obtain biomedical /sup 238/PuO/sub 2/ with a specific neutron yield of 3.10/sup 3/-4.10/sup 3/ (g /SUP ./ sec)/sup -1/, equivalent to metallic Pu 238, and with a content of gamma impurities sufficient to ensure a permissible exposure a permissible exposure does rate (EDR) of a mixture of neutron and gamma radiation. After carrying out the isotope exchange and purifying the initial sample of its gamma impurity elements, the authors obtain biomedical Pu 238 satisfying the indicated requirements king suitable for use in the power packs of medical devices. Taking the indicated specifications into account, the Ritm-1o and gamma radioisotope heat sources were designed, built, tested in models and under natural conditions, and then into production as radioisotope thermoelectric generators designed to power the electronic circuits of implanted pacemakers. The Ritm-MT and Gemma radioisotope thermoelectric generators described are basic units, which can be used as self-contained power supplies for electronic equipment with power requirements in the micromilliwatt range.

Pustovalov, A.A.; Bovin, A.V.; Fedorets, V.I.; Shapovalov, V.P.

1986-08-01

90

Radioisotopic heat source  

DOEpatents

Disclosed is a radioisotopic heat source and method for a long life electrical generator. The source includes plutonium dioxide shards and yttrium or hafnium in a container of tantalum-tungsten-hafnium alloy, all being in a nickel alloy outer container, and subjected to heat treatment of from about 1570$sup 0$F to about 1720$sup 0$F for about one h. (auth)

Jones, G.J.; Selle, J.E.; Teaney, P.E.

1975-09-30

91

Safety Test of Transport Packages for Radioisotopes.  

National Technical Information Service (NTIS)

The Division of Radioisotope Production, JAERI, has tested safety of type B(M), A and L packages according to the regulations of RI transportation. The type B(M) package weighing about 1800 kg. Used for transport of exp 192 Ir(6540 Ci) and exp 32 P(188 Ci...

S. Okane K. Tachikawa

1979-01-01

92

The production of patient dose level 99mTc medical radioisotope using laser-driven proton beams  

NASA Astrophysics Data System (ADS)

The medical isotope 99mTc (technetium) is used in over 30 million nuclear medical procedures annually, accounting for over 80% of the worldwide medical isotope usage. Its supply is critical to the medical community and a worldwide shortage is expected within the next few decades as current fission reactors used for its generation reach their end of life. The cost of build and operation of replacement reactors is high and as such, alternative production mechanisms are of high interest. Laser-accelerated proton beams have been widely discussed as being able to produce Positron Emission Tomography (PET) isotopes once laser architecture evolved to high repetition rates and energies. Recent experimental results performed on the Vulcan Laser Facility in the production of 99mTc through 100Mo (p,2n) 99mTc demonstrate the ability to produce this critical isotope at the scales required for patient doses using diode pumped laser architecture currently under construction. The production technique, laser and target requirements are discussed alongside a timeline and cost for a prototype production facility.

Clarke, R.; Dorkings, S.; Neely, D.; Musgrave, I.

2013-05-01

93

Large-scale purification of 90Sr from nuclear waste materials for production of 90Y, a therapeutic medical radioisotope.  

PubMed

A major limitation on the supply of the short-lived medical isotope 90Y (t1/2 = 64 h) is the available quantity of highly purified 90Sr generator material. A radiochemical production campaign was therefore undertaken to purify 1,500 Ci of 90Sr that had been isolated from fission waste materials. A series of alkaline precipitation steps removed all detectable traces of 137Cs, alpha emitters, and uranium and transuranic elements. Technical obstacles such as the buildup of gas pressure generated upon mixing large quantities of acid with solid 90Sr carbonate were overcome through safety features incorporated into the custom-built equipment used for 90Sr purification. Methods are described for analyzing the chemical and radiochemical purity of the final product and for accurately determining by gravimetry the quantities of 90Sr immobilized on stainless steel filters for future use. PMID:12878120

Wester, Dennis W; Steele, Richard T; Rinehart, Donald E; DesChane, Jaquetta R; Carson, Katharine J; Rapko, Brian M; Tenforde, Thomas S

2003-07-01

94

High yield production of the medical radioisotope 167Tm by the 167Er(d,2n) reaction.  

PubMed

As part of our systematic comparison of (p,n) and (d,2n) reactions, the excitation functions of the (167)Er(d,2n)(167)Tm production reaction and reactions leading to Tm radio-impurities were investigated up to 20 MeV. A stacked foil irradiation technique and ?-ray spectroscopy is used. The measured excitation functions are compared with results of ALICE-D, EMPIRE-D and TALYS reaction model codes and with data from our earlier investigations on natural Er. Thick target yields and contamination levels are discussed. A comparison with other charged particle production routes for (167)Tm shows that deuteron induced reactions are not competitive. PMID:20971015

Hermanne, A; Rebeles, R Adam; Tárkányi, F; Takács, S; Spahn, I; Ignatyuk, A V

2010-10-13

95

The Evolution of Galactic Boron and the Production Site of the Light Elements  

Microsoft Academic Search

The Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) has been used to obtain spectra of the 2500 A region in eight stars with metallicities ranging from [Fe\\/H] = -0.4 to -3.0, including the most metal-poor star ever observed for boron. Spectrum synthesis utilizing latest Kurucz model atmospheres has been used to determine the B abundance for

D. K. Duncan; F. Primas; L. M. Rebull; A. M. Boesgaard; Constantine P. Deliyannis; L. M. Hobbs; J. R. King; S. G. Ryan

1997-01-01

96

Production and characterization of boron- and silicon-doped carbon clusters  

Microsoft Academic Search

Boron- and silicon-doped carbon clusters of the type BmCn (m = 1?4) and SimCn (m = 1, 2) have been produced via the laser-vaporization cluster beam technique. The observed features of the intensity distribution in mass spectra suggest that B atoms can be incorporated into the clusters with much higher efficiency than Si atoms. The mass spectral evidence is also

Takumi Kimura; Toshiki Sugai; Hisanori Shinohara

1996-01-01

97

Boron in Very Metal-Poor Stars: Production of Light Elements in the Early Galaxy  

Microsoft Academic Search

We propose to derive the boron abundances in two very metal- deficient stars (-2.4>=[Fe\\/H]>=-2.9) by observing the B I 2496.7 A line with the G270M\\/SSA configuration. The abundances will be computed under NLTE conditions. Both stars have also accurate determinations of lithium (including 6Li for one of them), beryllium and oxygen abundances, which will allow us to compute and interpret

Ramon Lopez

1995-01-01

98

Cosmogenic radioisotopes on LDEF surfaces  

NASA Astrophysics Data System (ADS)

The radioisotope Be-7 was discovered in early 1990 on the front surface, and the front surface only, of the LDEF. A working hypothesis is that the isotope, which is known to be mainly produced in the stratosphere by spallation of nitrogen and oxygen nuclei with cosmic ray protons or secondary neutrons, diffuses upward and is absorbed onto metal surfaces of spacecraft. The upward transport must be rapid, that is, its characteristic time scale is similar to, or shorter than, the 53 day half-life of the isotope. It is probably by analogy with meteoritic metal atmospheric chemistry, that the form of the Be at a few 100 km altitude is as the positive ion Be(+) which is efficiently incorporated into the ionic lattice of oxides, such as Al2O3, Cr2O3, Fe2O3, etc., naturally occurring on surfaces of Al and stainless steel. Other radioisotopes of Be, Cl, and C are also produced in the atmosphere, and a search was begun to discover these. Of interest are Be-10 and C-14 for which the production cross sections are well known. The method of analysis is accelerator mass spectrometry. Samples from LDEF clamp plates are being chemically extracted, purified, and prepared for an accelerator run.

Gregory, J. C.; Albrecht, A.; Herzog, G.; Klein, J.; Middleton, R.

1992-06-01

99

Taming Highly Charged Radioisotopes  

NASA Astrophysics Data System (ADS)

The precise and accurate mass of short-lived radioisotopes is a very important parameter in physics. Contribution to the improvement of nuclear models, metrological standard fixing and tests of the unitarity of the Caibbibo-Kobayashi-Maskawa (CKM) matrix are a few examples where the mass value plays a major role. TRIUMF's ion trap for atomic and nuclear physics (TITAN) is a unique facility of three online ion traps that enables the mass measurement of short-lived isotopes with high precision (˜10-8). At present TITAN's electron beam ion trap (EBIT) increases the charge state to increase the precision, but there is no facility to significantly reduce the energy spread introduced by the charge breeding process. The precision of the measured mass of radioisotopes is linearly dependent on the charge state while the energy spread of the charged radioisotopes affects the precision adversely. To boost the precision level of mass measurement at TITAN without loosing too many ions, a cooler Penning trap (CPET) is being developed. CPET is designed to use either positively (proton) or negatively (electron) charged particles to reduce the energy spread via sympathetic cooling. Off-line setup of CPET is complete. Details of the working principles and updates are presented

Chowdhury, Usman; Eberhardt, Benjamin; Jang, Fuluni; Schultz, Brad; Simon, Vanessa; Delheij, Paul; Dilling, Jens; Gwinner, Gerald

2012-10-01

100

Reducing Boron Toxicity by Microbial Sequestration  

SciTech Connect

While electricity is a clean source of energy, methods of electricity-production, such as the use of coal-fired power plants, often result in significant environmental damage. Coal-fired electrical power plants produce air pollution, while contaminating ground water and soils by build-up of boron, which enters surrounding areas through leachate. Increasingly high levels of boron in soils eventually overcome boron tolerance levels in plants and trees, resulting in toxicity. Formation of insoluble boron precipitates, mediated by mineral-precipitating bacteria, may sequester boron into more stable forms that are less available and toxic to vegetation. Results have provided evidence of microbially-facilitated sequestration of boron into insoluble mineral precipitates. Analyses of water samples taken from ponds with high boron concentrations showed that algae present contained 3-5 times more boron than contained in the water in the samples. Boron sequestration may also be facilitated by the incorporation of boron within algal cells. Experiments examining boron sequestration by algae are in progress. In bacterial experiments with added ferric citrate, the reduction of iron by the bacteria resulted in an ironcarbonate precipitate containing boron. An apparent color change showing the reduction of amorphous iron, as well as the precipitation of boron with iron, was more favorable at higher pH. Analysis of precipitates by X-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectroscopy revealed mineralogical composition and biologicallymediated accumulation of boron precipitates in test-tube experiments.

Hazen, T.; Phelps, T.J.

2002-01-01

101

Radioisotopes as Political Instruments, 1946-1953  

PubMed Central

The development of nuclear “piles,” soon called reactors, in the Manhattan Project provided a new technology for manufacturing radioactive isotopes. Radioisotopes, unstable variants of chemical elements that give off detectable radiation upon decay, were available in small amounts for use in research and therapy before World War II. In 1946, the U.S. government began utilizing one of its first reactors, dubbed X-10 at Oak Ridge, as a production facility for radioisotopes available for purchase to civilian institutions. This program of the U.S. Atomic Energy Commission was meant to exemplify the peacetime dividends of atomic energy. The numerous requests from scientists outside the United States, however, sparked a political debate about whether the Commission should or even could export radioisotopes. This controversy manifested the tension in U.S. politics between scientific internationalism as a tool of diplomacy, associated with the aims of the Marshall Plan, and the desire to safeguard the country’s atomic monopoly at all costs, linked to American anti-Communism. This essay examines the various ways in which radioisotopes were used as political instruments—both by the U.S. federal government in world affairs, and by critics of the civilian control of atomic energy—in the early Cold War.

Creager, Angela N. H.

2009-01-01

102

Radioisotopes as Political Instruments, 1946-1953.  

PubMed

The development of nuclear "piles," soon called reactors, in the Manhattan Project provided a new technology for manufacturing radioactive isotopes. Radioisotopes, unstable variants of chemical elements that give off detectable radiation upon decay, were available in small amounts for use in research and therapy before World War II. In 1946, the U.S. government began utilizing one of its first reactors, dubbed X-10 at Oak Ridge, as a production facility for radioisotopes available for purchase to civilian institutions. This program of the U.S. Atomic Energy Commission was meant to exemplify the peacetime dividends of atomic energy. The numerous requests from scientists outside the United States, however, sparked a political debate about whether the Commission should or even could export radioisotopes. This controversy manifested the tension in U.S. politics between scientific internationalism as a tool of diplomacy, associated with the aims of the Marshall Plan, and the desire to safeguard the country's atomic monopoly at all costs, linked to American anti-Communism. This essay examines the various ways in which radioisotopes were used as political instruments-both by the U.S. federal government in world affairs, and by critics of the civilian control of atomic energy-in the early Cold War. PMID:20725612

Creager, Angela N H

2009-01-01

103

Radioisotope powered light sources  

SciTech Connect

Radioisotopes have been used for a number of years to excite phosphors to produce visible light. The advent of the nuclear age, however, made possible the preparation of radionuclides in larger quantities at relatively low prices, and with radiation properties that greatly expanded the potential applications for such lights. Current energy conservation needs and inflation leading to even higher costs for maintenance and capital equipment has provided the incentive for development of illuminators for air field markers using both byproduct krypton-85 and processed tritium. Background and current status of these developments are discussed.

Case, F.N.; Remini, W.C.

1980-01-01

104

List of DOE radioisotope customers with summary of radioisotope shipments FY 1978  

SciTech Connect

The purpose of the document is to list DOE's radioisotopes production and distribution activities by its facilities at Argonne National Laboratory; Pacific Northwest Laboratory; Brookhaven National Laboratory; Hanford Engineering Development Laboratory; Idaho Operations Office; Los Alamos Scientific Laboratory; Mound Facility; Oak Ridge National Laboratory; Savannah River Laboratory; and UNC Nuclear Industries, Inc.

Burlison, J.S.; Laidler, R.I. (comps.)

1979-05-01

105

Determination of boron and other elements in food and agricultural products by PGAA  

SciTech Connect

In-beam thermal neutron capture prompt gamma-ray activation analysis (PGAA) can provide accurate concentrations for hydrogen, boron, nitrogen, sodium, chlorine, potassium, sulfur, calcium, and cadmium in food and agricultural materials when care is taken to account for neutron-scattering effects. The hydrogen concentration of a given matrix affects element sensitivities and background count rates. Because the materials of interest, especially foods, vary greatly in hydrogen concentration, specialized packaging and standardization methods were needed to perform analyses properly. The purpose of the work discussed in this paper was to establish methods to lower limits of detection and minimize sources of error, especially those due to variations in the hydrogen concentration and the target shape.

Anderson, D.L.; Cunningham, W.C. (FDA, Gaithersburg, MD (United States))

1992-01-01

106

Minerals Yearbook 1989: Boron  

SciTech Connect

U.S. production and sales of boron minerals and chemicals decreased during the year. Domestically, glass fiber insulation was the largest use for borates, followed by sales to distributors, textile-grade glass fibers, and borosilicate glasses. California was the only domestic source of boron minerals. The United States continued to provide essentially all of its own supply while maintaining a strong position as a source of sodium borate products and boric acid exported to foreign markets. Supplementary U.S. imports of Turkish calcium borate and calcium-sodium borate ores, borax, and boric acid, primarily for various glass uses, continued.

Lyday, P.A.

1990-08-01

107

Measured variation in boron loads reaching European sewage treatment works  

Microsoft Academic Search

Per capita boron loads reaching 48 sewage treatment works (STWs) in The Netherlands, Germany, Italy, and the UK have been determined from monitoring data. These have been compared with the per capita input predicted from boron in detergents, as determined from detergent product sales data. The resulting distribution of the ratios of measured boron to boron predicted from consumer usage

K. K. Fox; G. Cassani; A. Facchi; F. R. Schröder; C. Poelloth; M. S. Holt

2002-01-01

108

Alternative Radioisotopes for Heat and Power Sources  

NASA Astrophysics Data System (ADS)

Production of 238Pu requires considerable facilities including a nuclear reactor and reprocessing plants that are very expensive to build and operate. Thus, a more economical alternative is very attractive to the industry. There are many alternative radioisotopes that exist but few that satisfy the criteria of performance, availability and cost to produce. Any alternative to 238Pu must exist in a chemical form that is compatible with the materials required to safely encapsulate the heat source at the high temperatures of operation and potential launch failure scenarios. The chemical form must also have suitable thermal properties to ensure maximum energy conversion efficiencies when integrated into radioisotope thermoelectric generators over the required mission durations. In addition, the radiation dose must be low enough for operators during production and not so prohibitive that excessive shielding mass is required on the space craft. This paper will focus on the preferred European alternative of 241Am, and the issues that will need to be addressed.

Tinsley, T.; Sarsfield, M.; Rice, T.

109

Boron geochemistry of mud volcano products and their significance for global B cycling  

NASA Astrophysics Data System (ADS)

Mud volcanism is a global phenomenon in mostly convergent margin settings, whose nature has long been subject to scientific investigation. However, only recently its significance has been unravelled by quantitative studies in well-investigated submarine environments, like large accretionary complexes. The fluid flux through active mud volcanoes has been estimated to exceed that of the frontal accretionary prism (Kopf et al. 2001, EPSL 189), and may have done so in earlier earth history. We report results from a systematic B geochemical study of pore fluids, muds and clasts of onshore and offshore mud volcanoes all over the world (Kopf and Deyhle, 2002, Chem. Geol., 192). When tied into results from hydrothermal geochemical experiments in the laboratory (You et al. 1996, EPSL 140), the B geochemistry proofs to be a powerful tracer to estimate the depth of fluid and mud mobilization below ground. Boron adsorbed to clay minerals is preferably donated to the fluid when either tectonic stress (vertical and/or lateral compaction) or temperature increase. Here, we report variations in B content and B isotopes in mud volcano deposits as a result of different history of the material prior to extrusion. Results reflect the regional geology of the study areas, ranging from dewatering of undercompacted marine sediments in accretionary prisms (Barbados, Makran, Mediterranean Sea) to diagenetic reactions in mud volcanoes of orogenic belts (Malaysia, Pakistan, Georgia, Taman Peninsula, Western Alps). Boron shows maximum enrichment in the fluid phase (owing to desorption in the mud) when faulting roots deepest and deformation is strongest. Mud domes juxtaposing out-of-sequence faults in the Caucasus orogenic wedge show mud B contents 8x marine sediment and fluid B contents up to 25x seawater. Deep-seated, B-rich fluids liquefy clay-bearing strata to facilitate mud extrusion, allowing the clay to re-adsorb B in the process. B isotopic composition of the mud decreases with incipient stress and mobilization depth. Given the abundance and high discharge rates of mud volcanoes along subduction zones, this process generally affects chemical and fluid budgets in the subduction factory. Given the abundance and high discharge rates of mud volcanoes, it clearly has to be considered a major backflux mechanism in global B cycling from the lithosphere to the hydrosphere.

Deyhle, A.; Kopf, A.

2003-04-01

110

Therapeutic clinical applications of reactor-produced radioisotopes  

SciTech Connect

One of the most rapidly growing areas of clinical nuclear medicine is the therapeutic use of radioisotopes for applications in oncology, rheumatology and, more recently, interventional cardiology. With the rapidly increasing development and evaluation of new agents, their introduction into clinical use, and commercialization, the availability of high levels of therapeutic reactor-produced neutron-rich radioisotopes is of increasing importance. The goals of this paper are to discuss the issues associated with optimization of the production and processing of reactor-produced radioisotopes for therapy, with special emphasis on {sup 188}W, and the optimization of the use of the {sup 188}W/{sup 188}Re generator. In addition, other key examples of therapeutic radioisotopes of current interest and their specific clinical applications are discussed.

Knapp, F.F. Jr. [Oak Ridge National Lab., TN (United States)

1997-12-01

111

Boron alloy  

SciTech Connect

This paper describes a ferro-boron alloy produced in situ in a basic oxygen furnace, an induction furnace, or an electric furnace, or in combination with a mixing vessel. It comprises: 1.4% to 15% by weight boron; less than 0.002% by weight nitrogen; less than about 0.2% by weight carbon; less than about 0.01% by weight aluminum; and the balance iron with minute amounts of residuals.

Sussman, R.C.; Evans, L.G.

1990-06-26

112

Minerals Yearbook, 1992: Boron.  

National Technical Information Service (NTIS)

U.S. production and sales of boron minerals and chemicals decreased during the year. Domestically, glass fiber insulation was the largest use for borates, followed be sales to textile-grade glass fibers, and soaps and detergents. California was the only d...

P. A. Lyday

1993-01-01

113

Minerals Yearbook, 1991: Boron.  

National Technical Information Service (NTIS)

U.S. production and sales of boron minerals and chemicals decreased during the year. Domestically, glass fiber insulation was the largest use for borates, followed by sales to textile-grade glass fibers, sales to distributors, and borosilicate glasses. Ca...

P. A. Lyday

1992-01-01

114

High-calcium coal combustion by-products: Engineering properties, ettringite formation, and potential application in solidification and stabilization of selenium and boron  

Microsoft Academic Search

Four high-calcium coal combustion by-products (two pulverized coal fly ashes (PCFA), a flue gas desulfurization (FGD) residue, and an atmospheric fluidized bed combustion (AFBC) fly ash), were tested for engineering properties and ability to immobilize boron and selenium. These data are needed to explore high-volume utilization in engineered structures or in solidification\\/stabilization (S\\/S) technology. Strengths of cured pastes (91 days),

B. Docktor; K. E. Eylands; J. S. Thompson; D. J. Hassett

1995-01-01

115

Radioisotope powered AMTEC systems  

NASA Astrophysics Data System (ADS)

Alkali metal thermal to electric converter (AMTEC) systems are being developed for high performance spacecraft power systems, including small, general purpose heat source (GPHS) powered systems. Several design concepts have been evaluated for the power range from 75 W to 1 kW. The specific power for these concepts has been found to be as high as 18-20 W/kg and 22 kW/m(exp 3). The projected area, including radiators, has been as low as 0.4 m(exp 2)/kW. AMTEC power systems are extremely attractive, relative to other current and projected power systems, because AMTEC offers high power density, low projected area, and low volume. Two AMTEC cell design types have been identified. A single-tube cell is already under development and a multitube cell design, to provide additional power system gains, has undergone proof-of-principle testing. Solar powered AMTEC (SAMTEC) systems are also being developed, and numerous terrestrial applications have been identified for which the same basic AMTEC cells being developed for radioisotope systems are also suitable.

Ivanenok, Joseph F., III; Sievers, Robert K.

1994-11-01

116

Short-lived fission product measurements from >0.1 MeV neutron-induced fission using boron carbide.  

SciTech Connect

A boron carbide shield was designed, custom fabricated, and used to create a fast fission energy neutron spectrum. The fissionable isotopes 233, 235, 238U, 237Np, and 239Pu were separately placed inside of this shield and irradiated under pulsed conditions at the Washington State University 1 MW TRIGA reactor. A unique set of fission product gamma spectra were collected at short times (4 minutes to 1 week) post-fission. Gamma spectra were collected on single-crystal high purity germanium detectors and on Pacific Northwest National Laboratory's (PNNL's) Direct Simultaneous Measurement (DSM) system composed of HPGe detectors connected in coincidence. This work defines the experimental methods used to produce and collect the gamma data, and demonstrates the validity of the measurements. It is important to fully document this information so the data can be used with high confidence for the advancement of nuclear science and non-proliferation applications. The gamma spectra collected in these and other experiments will be made publicly available at https://spcollab.pnl.gov/sites/gammadata or via the link at http://rdnsgroup.pnl.gov. A revised version of this publication will be posted with the data to make the experimental details available to those using the data.

Finn, Erin C.; Metz, Lori A.; Greenwood, Lawrence R.; Pierson, Bruce D.; Friese, Judah I.; Kephart, Rosara F.; Kephart, Jeremy D.

2012-02-01

117

Preliminary Investigation of Effects on the Environment of Boron, Indium Nickel, Selenium, Tin, Vanadium and Their Compounds. Volume I - Boron.  

National Technical Information Service (NTIS)

Contents: Boron industry in the United States; Production; Uses of boron compounds; Current practices; Environmental contamination; Monitoring and analysis; Chemical reactivity; Biology; Environmental effects; Toxicity; Current regulations and effects lev...

1975-01-01

118

Why boron?  

Microsoft Academic Search

It is now more than 80 years since boron was convincingly demonstrated to be essential for normal growth of higher plants. However, its biochemical role is not well understood at the moment. Several recent reviews propose that B is implicated in three main processes: keeping cell wall structure, maintaining membrane function, and supporting metabolic activities. However, in the absence of conclusive

Luis Bolaños; Krystyna Lukaszewski; Ildefonso Bonilla; Dale Blevins

2004-01-01

119

Life cycle assessment as a tool for improving process performance: A case study on boron products  

Microsoft Academic Search

This paper explores the use of LCA as a tool for process environmental management, thereby moving the focus from product to\\u000a process oriented analysis. The emphasis is on Improvement Assessment in which the “hot spots” in the system are targeted for\\u000a maximum environmental improvements. In this context, it is useful to use multiobjective optimisation which renders Valuation\\u000a unnecessary.\\u000a \\u000a The approach

Adisa Azapagic; Roland Clift

1999-01-01

120

Radioisotope Applications in Petroleum and Gas Industries.  

National Technical Information Service (NTIS)

The principal radioisotopic technique used for studying and /or controling the drilling, completion, treatment and oil well secondary recovery operations are described. In this cases the radioisotopes are employed almost exclusively as 'markers', in the f...

A. C. Castagnet E. G. Agudo U. Duarte

1974-01-01

121

Modular radioisotope AMTEC power system  

NASA Astrophysics Data System (ADS)

The Alakli Metal Thermal to Electric Converter (AMTEC) technology is extremely amenable to a modular configuration. Several modular designs have been proposed for coupling to the radioisotope general purpose heat source (GPHS). Current AMTEC cell designs, producing approximately 5 W at over 20% efficiency, can be integrated into a radioisotope heated module that provides 10-28 per 250 Wth GPHS. The mass of these modules is approximately 4 kg. The cell design used in this concept is under development. The first generation model has already been operated for one year. Smaller, higher efficiency cells are now being fabricated.

Sievers, Robert K.; Hunt, Thomas K.; Ivanenok, Joseph F.; Pantolin, Jan E.; Butkiewicz, David A.

1993-01-01

122

Development of Radioisotope Energy Conversion Systems - efficient Radioisotopic Power  

Microsoft Academic Search

Topical area of the conference: (10) Space Power and Propulsion . Abstract: The topic of this paper is the development of the Radioisotope Energy Conversion System (RECS) in a project which is utilizing analytical computational assisted Design and experimental Research in the investigation of fluorescers and effective transducers for the conversion of energy.

Eric V. Steinfelds; Tushar K. Ghosh; Mark A. Prelas; Robert V. Tompson; Sudarshan K. Loyalka

123

Computation and Analysis of the Global Distribution of the Radioxenon Isotope 133Xe based on Emissions from Nuclear Power Plants and Radioisotope Production Facilities and its Relevance for the Verification of the Nuclear-Test-Ban Treaty  

NASA Astrophysics Data System (ADS)

Monitoring of radioactive noble gases, in particular xenon isotopes, is a crucial element of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The capability of the noble gas network, which is currently under construction, to detect signals from a nuclear explosion critically depends on the background created by other sources. Therefore, the global distribution of these isotopes based on emissions and transport patterns needs to be understood. A significant xenon background exists in the reactor regions of North America, Europe and Asia. An emission inventory of the four relevant xenon isotopes has recently been created, which specifies source terms for each power plant. As the major emitters of xenon isotopes worldwide, a few medical radioisotope production facilities have been recently identified, in particular the facilities in Chalk River (Canada), Fleurus (Belgium), Pelindaba (South Africa) and Petten (Netherlands). Emissions from these sites are expected to exceed those of the other sources by orders of magnitude. In this study, emphasis is put on 133Xe, which is the most prevalent xenon isotope. First, based on the emissions known, the resulting 133Xe concentration levels at all noble gas stations of the final CTBT verification network were calculated and found to be consistent with observations. Second, it turned out that emissions from the radioisotope facilities can explain a number of observed peaks, meaning that atmospheric transport modelling is an important tool for the categorization of measurements. Third, it became evident that Nuclear Power Plant emissions are more difficult to treat in the models, since their temporal variation is high and not generally reported. Fourth, there are indications that the assumed annual emissions may be underestimated by factors of two to ten, while the general emission patterns seem to be well understood. Finally, it became evident that 133Xe sources mainly influence the sensitivity of the monitoring system in the mid-latitudes, where the network coverage is particularly good.

Wotawa, Gerhard; Becker, Andreas; Kalinowski, Martin; Saey, Paul; Tuma, Matthias; Zähringer, Matthias

2010-05-01

124

Inhomogeneous big bang nucleosynthesis: Upper limit on ?b and production of lithium, beryllium, and boron  

NASA Astrophysics Data System (ADS)

We examine the big bang nucleosynthesis (BBN) process in the presence of small-scale baryon inhomogeneities. Primordial abundance yields for D, 4He, 6Li, 7Li, 9Be, and 11B are computed for wide ranges of parameters characterizing the inhomogeneities taking account of all relevant diffusive and hydrodynamic processes. These calculations may be of interest due to (a) recent observations of the anisotropies in the cosmic microwave background radiation favoring slightly larger baryonic contribution to the critical density, ?b, than allowed by a standard BBN scenario and (b) new observational determinations of 6Li and 9Be in metal-poor halo stars. We find considerable parameter space in which production of D and 4He is in agreement with observational constraints even for ?bh2 a factor 2 or 3 larger than the ?b inferred from standard BBN. Nevertheless, in this parameter space synthesis of 7Li in excess of the inferred 7Li abundance on the Spite plateau results. Production of 6Li, 9Be, and 11B in inhomogeneous BBN scenarios is still typically well below the abundance of these isotopes observed in the most metal-poor stars to date thus neither confirming nor rejecting inhomogeneous BBN. In an Appendix we summarize results of a reevaluation of baryon diffusion constants entering inhomogeneous BBN calculations.

Jedamzik, Karsten; Rehm, Jan B.

2001-07-01

125

Radioisotopes for research on and control of mosquitos  

PubMed Central

Practical applications of radioactive isotopes in medicine, science, and industry have multiplied enormously during the past five years. In this paper, the author attempts to gather what is known about the use of radioactive isotopes in the research on malaria control. The development of the uranium pile for large-scale production of radioisotopes and technical progress in the making of reliable electronic equipment have greatly contributed to the application of radioactive tracers in biological research. The present knowledge of radioisotopes in mosquito and in insecticide research is discussed. ImagesFIG. 1

Bruce-Chwatt, Leonard J.

1956-01-01

126

Production of Lithium, Beryllium and Boron and Analysis of Nuclear Gamma-Ray Line Emission in Active Star Forming Regions  

NASA Astrophysics Data System (ADS)

A model for the formation of the elements Lithium, Beryllium and Boron is presented. The main formation mechanism for these elements has been known to be a process called nuclear spallation. Spallation between protons or alpha particles and the Carbon, Nitrogen and Oxygen nuclei result in the production of the isotopes of Li, Be and B. The originally proposed site for spallation, well-mixed interstellar medium, was found to be inconsistent with the recent observations of linearly varying abundances of Be and B with respect to the metallicity in metal-poor stars. We propose a model for spallation occuring in the unmixed ejecta of supernova as the primary mode of production of the isotopes of Li, Be and B. This scenario was simulated by writing a Monte-Carlo code. The results in terms of the energy required for spallation are feasible compared to the total energy released in a supernova explosion. The calculated isotopic ratios produced were found to generally agree with the observed values. Recent observations of Orion region showing excess flux in 3-7 MeV range, identified as Carbon and Oxygen nuclear deexcitation lines, were followed by models proposing spallation in the vicinity of supernova by collision between energetic C), O nuclei and protons or alpha particles in the surrounding ambient medium. We searched for similar emission from other nearby OB associations, the Cygnus region. Cygnus region contains several large OB associations, including Wolf-Rayet stars, and has a total wind power almost 100 times larger than that in the Orion complex. We present the results from our study of the gamma-ray emission in the 0.75-30 MeV range from the Cygnus region using data from the COMPTEL instrument onboard the Compton Gamma-Ray Observatory (CGRO). In the 3-7 MeV band, where Orion emission is most prominent, we do not find significant emission. We do find significant emission at 1.8 MeV, resulting from the radioactive decay of 26Al. This flux is consistent with the amount predicted from known sources of 26Al in this region.

Majmudar, Deepa Paresh

127

Radioisotopes In Biology And Agriculture.  

National Technical Information Service (NTIS)

Highlights a lecture by Dr. Howard Curtis of Brookhaven National Laboratory, who touches on some of the up-to-date applications of atomic energy to biology and agriculture. Shows the importance of radioisotopic tracers in the determination of the structur...

1994-01-01

128

How to Handle Radioisotopes Safely.  

ERIC Educational Resources Information Center

|This booklet is one in a series of instructional aids designed for use by elementary and secondary school science teachers. The various units and forms of radioactive materials used by teachers are first considered. Then, the quantities of radioisotopes that a person may possess without a license from the Atomic Energy Commission (AEC) are…

Sulcoski, John W.

129

Status Report Radioisotopic Propulsion Systems  

Microsoft Academic Search

Preliminary analysis of radioisotopic propulsion systems indicates considerable potential for application to scientific probes provided current engineering postulations can be realized. Typical applications, as indicated by analysis to date, would be high energy space missions such as solar probes to distances of approximately 0.05 A. U. and explorer probes in deep space out to the vicinity of Saturn. In order

J. C. Whiton

1965-01-01

130

An overview of the Radioisotope Thermoelectric Generator Transporation System Program  

Microsoft Academic Search

Radioisotope Thermoelectric Generators (RTG) convert the heat generated by radioactive decay to electricity using thermocouples. RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance once assembled and tested. These factors make RTGs particularly attractive for use in spacecraft However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they

McCoy

1995-01-01

131

List of ERDA radioisotope customers with summary of radioisotope shipments FY 1977 (plus the transition quarter)  

SciTech Connect

The thirteenth edition of the radioisotope customer list gives ERDA's (now DOE) FY-1977 and transition quarter radioisotope production and distribution activities by its facilities at Argonne National Laboratory; Pacific Northwest Laboratory; Brookhaven National Laboratory; Hanford Engineering Development Laboratory; Idaho Operations Office; Los Alamos Scientific Laboratory; Mound Laboratory; Oak Ridge National Laboratory; Savannah River Laboratory; and United Nuclear Industries, Inc. The information is divided into four sections. Sect. I is an alphabetical list of domestic and foreign customers and their addresses. Sect. II is an alphabetical list of isotopes that are cross-referenced to customer numbers and divided into the domestic and foreign categories. Sect. III is an alphabetical list of states and countries, and is also cross-referenced to customer numbers, indicating geographical concentrations of isotope users. Sect. IV summarizes the FY-1977 radioisotope shipment activities of laboratories in a comprehensive table providing an alphabetical listing of the isotopes and their suppliers. The shipments, quantities, and dollars are broken down for each isotope under the domestic, foreign, and project (ERDA facilities) categories, and the total figures for each isotope are also provided.

Simmons, J.L. (comp.)

1978-07-01

132

Characterization of electrodeposited elemental boron  

SciTech Connect

Elemental boron was produced through electrowinning from potassium fluoroborate dissolved in a mixture of molten potassium fluoride and potassium chloride. The characteristics of the electrodeposited boron (raw boron) as well as the water and acid-leached product (processed boron) were studied. The chemical purity, specific surface area, size distribution of particles and X-ray crystallite size of the boron powders were investigated. The morphology of the deposits was examined using scanning electron microscopy (SEM). The chemical state of the matrix, as well as the impurity phases present in them, was established using X-ray photoelectron spectroscopy (XPS). In order to interpret and understand the results obtained, a thermodynamic analysis was carried out. The gas-phase corrosion in the head space as well as the chemistry behind the leaching process were interpreted using this analysis. The ease of oxidation of these powders in air was investigated using differential thermal analysis (DTA) coupled with thermogravimetry (TG). From the results obtained in this study it was established that elemental boron powder with a purity of 95-99% could be produced using a high temperature molten salt electrowinning process. The major impurities were found to be oxygen, carbon, iron and nickel.

Jain, Ashish [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102 (India); Anthonysamy, S. [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102 (India)], E-mail: sas@igcar.gov.in; Ananthasivan, K.; Ranganathan, R. [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102 (India); Mittal, Vinit; Narasimhan, S.V. [Water and Steam Chemistry Division, BARC (F), Kalpakkam, 603102 (India); Vasudeva Rao, P.R. [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102 (India)

2008-07-15

133

Production of Lithium, Beryllium, and Boron by Hypernovae and the Possible Hypernova-Gamma-Ray Burst Connection  

Microsoft Academic Search

We investigate a possible nucleosynthetic signature of highly energetic explosions of C-O cores (``hypernovae'' [HNe]) that might be associated with gamma-ray bursts (GRBs). We note that the direct impact of C- and O-enriched hypernova ejecta on the ambient hydrogen and helium leads to spallation reactions that can produce large amounts of the light nuclides lithium, beryllium, and boron (LiBeB). Using

Brian D. Fields; Frédéric Daigne; Michel Cassé; Elisabeth Vangioni-Flam

2002-01-01

134

Quarterly Progress Report for Radioisotope Powered Cardiac Pacemaker Program, August 1, 1973-October 31, 1973.  

National Technical Information Service (NTIS)

Progress is reported on the development of a radioisotope powered cardiac pacemaker. The developmental work is discussed under the following tasks: Program management; control and planning; reliability and quality assurance; system fabrication and product...

1973-01-01

135

POTENTIALS OF RADIOISOTOPE ELECTROSTATIC PROPULSION  

Microsoft Academic Search

The potentialities and problems of a radioisotope electrostatic ; propulsion system for future space missions are discussed. The proposed ; operation of an electrogenerator using Ce¹⁴⁴ -- Pr¹⁴⁴ fuel is ; described. The availability and cost of Ce¹⁴⁴ are considered, along with ; payload radiation damage, spacecraft design, launch-pad and boost hazards, and ; interplanetary mission performance. The anticipated availability

W. R. Mickelsen; C. A. Jr. Low

1963-01-01

136

Estimativa preliminar das taxas de dose no compartimento de operacao da celula de recepcao de radioisotopos do RPR. (Preliminary estimation of the dose rates of the operation room of the RPR radioisotope cell).  

National Technical Information Service (NTIS)

During the preliminary studies, about the installations layout of a radioisotope production reactor, the possibility of construction of a radioisotope cell at the reactor building has been investigated. The decisions about that construction has considered...

A. C. S. Rocha J. J. G. Silva J. L. S. Pina P. W. Fajardo

1986-01-01

137

Transport of the radioisotopes iodine-131, cesium-134, and cesium-137 from the fallout following the accident at the Chernobyl nuclear reactor into cheesemaking products  

Microsoft Academic Search

The transport of radiation contamination from milk to products of the cheese making process has been studied. The concentration of radioactive iodine and cesium in samples of sheep milk and cheese (Gruyere) products was measured for 10 consecutive production d. Milk with concentration 100 Bq\\/L in each of the radionuclides ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs cheese with concentration 82.2 +\\/- 3.9

P. A. Assimakopoulos; K. G. Ioannides; Pak; C. V. Paradopoulou

1987-01-01

138

List of DOE radioisotope customers with summary of radioisotope shipments, FY 1985  

SciTech Connect

This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1) isotope suppliers, facility contacts, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfer - FY 1985.

Baker, D.A.

1986-08-01

139

Generation of a boron ion beam in a modified ion source for semiconductor applications  

SciTech Connect

Presented here are results of experimental studies on the production of intense beams of boron ions using a modified Bernas-Calutron ion source. Instead of using the conventional boron-trifluoride gas, a solid lithium-boron-tetrafluoride compound was heated to release boron-trifluoride. For optimum ion source parameters the measured 25-41 mA of total ion beam current was composed of 70% singly charged and about 1% doubly charged boron ions.

Gushenets, V.I.; Bugaev, A.S.; Oks, E.M.; Yushkov, G.Yu.; Hershcovitch, Ady; Johnson, B.M.; Kulevoy, T.V.; Poole, H.J.; Swarovsky, A.Ya. [High Current Electronics Institute, Russian Academy of Sciences, Tomsk (Russian Federation); Brookhaven National Laboratory, Upton, New York (United States); Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); PVI, Oxnard, California (United States); A.A. Bochvara Scientific Research Institute for Inorganic Materials, Siberian Branch (Russian Federation)

2006-03-15

140

Magnetron sputtered boron films and Ti/B multilayer structures  

DOEpatents

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

Makowiecki, Daniel M. (Livermore, CA); Jankowski, Alan F. (Livermore, CA)

1995-01-01

141

Magnetron sputtered boron films and TI/B multilayer structures  

DOEpatents

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

Makowiecki, Daniel M. (Livermore, CA); Jankowski, Alan F. (Livermore, CA)

1993-01-01

142

Magnetron sputtered boron films and TI/B multilayer structures  

DOEpatents

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for ultra-thin band pass filters as well as the low Z element in low Z/high Z mirrors which enhance reflectivity from grazing to normal incidence.

Makowiecki, D.M.; Jankowski, A.F.

1993-04-20

143

Radioisotope penogram in diagnosis of vasculogenic impotence.  

PubMed

A radioisotope technique to estimate penile blood flow is described. The radioisotope penogram is noninvasive and gives a dynamic evaluation of the arterial supply, venous drainage, and blood flow in the corporeal bodies. The penogram is a valuable adjunct in evaluation of patients with vasculogenic impotence. PMID:6293142

Fanous, H N; Jevtich, M J; Chen, D C; Edson, M

1982-11-01

144

Power from Radioisotopes, Understanding the Atom Series.  

ERIC Educational Resources Information Center

|This 1971 revision deals with radioisotopes and their use in power generators. Early developments and applications for the Systems for Nuclear Auxiliary Power (SNAP) and Radioisotope Thermoelectric Generators (RTGs) are reviewed. Present uses in space and on earth are included. Uses in space are as power sources in various satellites and space…

Corliss, William R.; Mead, Robert L.

145

Power from Radioisotopes, Understanding the Atom Series.  

ERIC Educational Resources Information Center

This 1971 revision deals with radioisotopes and their use in power generators. Early developments and applications for the Systems for Nuclear Auxiliary Power (SNAP) and Radioisotope Thermoelectric Generators (RTGs) are reviewed. Present uses in space and on earth are included. Uses in space are as power sources in various satellites and space…

Corliss, William R.; Mead, Robert L.

146

High efficiency radioisotope thermophotovoltaic prototype generator  

Microsoft Academic Search

A radioisotope thermophotovoltaic generator space power system (RTPV) is lightweight, low-cost alternative to the present radioisotope thermoelectric generator system (RTG). The fabrication of such an RTPV generator has recently become feasible as the result of the invention of the GaSb infrared sensitive photovoltaic cell. Herein, we present the results of a parametric study of emitters and optical filters in conjuction

James E. Avery; John E. Samaras; Lewis M. Fraas; Richard Ewell

1995-01-01

147

Synthesis and Characterization of a Boronated Metallophthalocyanine for Boron Neutron Capture Therapy.  

PubMed

Synthesis of the first fully characterized, water-soluble boronated phthalocyanine is reported. Reaction of 4-nitrophthalonitrile with dimethyl malonate in the presence of base yielded dimethyl (3,4-dicyanophenyl)malonate which was converted into dimethyl (3,4-dicyanophenyl)propargylmalonate by sequential treatment with potassium hydroxide and propargyl bromide. Formation of the o-carborane cage was accomplished by reaction of the alkyne with decaborane in acetonitrile at reflux. High-temperature solid state condensation of the resulting o-carboranylphthalonitrile with cobalt(II) chloride followed by ester deprotection and cation exchange provided the water-soluble closo-carbonylphthalocyanine product. The product contains 40 boron atoms (27% boron by weight) and may be useful as a tumor-seeking boron delivery agent for boron neutron capture therapy of cancer. PMID:11666577

Kahl, Stephen B.; Li, Jing

1996-06-19

148

Nuclear model calculations on the production of {sup 125,123}Xe and {sup 133,131,129,128}Ba radioisotopes  

SciTech Connect

In this study, production rates of {sup 125,123}Xe and {sup 133,131,129,128}Ba medical isotopes produced by {sup 127}I(p, 3n){sup 125}Xe, {sup 127}I(p, 5n){sup 123}Xe, {sup 133}Cs(p, n){sup 133mg}Ba, {sup 133}Cs(p, 3n){sup 131mg}Ba, {sup 133}Cs(p, 5n){sup 129}Ba, and {sup 133}Cs(p, 6n){sup 128}Ba reactions have been investigated up to 100 MeV incident proton energy. The preequilibrium calculations involve the hybrid model, the geometry-dependent hybrid model and the cascade exciton model. The calculated results are compared with the experimental data taken from the literature.

Aydin, A., E-mail: aaydin@kku.edu.tr; Pekdogan, H. [Kirikkale University, Faculty of Arts and Sciences (Turkey); Tel, E. [Osmaniye Korkut Ata University, Faculty of Arts and Sciences (Turkey); Kaplan, A. [Sueleyman Demirel University, Faculty of Arts and Sciences (Turkey)

2012-03-15

149

Boron in chondritic meteorites  

Microsoft Academic Search

Alpha-track images (ATI), prepared by etching neutron-irradiated cellulose nitrate films attached to polished thin sections of meteorites, provide useful qualitative maps of boron and lithium distribution. However, extreme care must be taken to avoid contamination during preparation, particularly by boron in diamond polishing paste. Boron and lithium are virtually absent from chondrules, metal and sulfide grains in carbonaceous and ordinary

D. M. Shaw; M. D. Higgins; R. W. Hinton; M. G. Truscott; T. A. Middleton

1988-01-01

150

Radioisotope requirements and usage in the radiopharmaceutical industry  

SciTech Connect

Radioisotopes are used extensively in many different productive and beneficial human endeavors. Amersham International, a U.K.-based company originating in the British Scientific Civil Service during World War II, has been actively involved in many of these activities for more than 50 yr. Today they are one of the world`s largest suppliers of radioactive compounds and scaled radiation sources for use in industrial quality and safety assurance, life science research, and medicine. This paper outlines one of these applications: the use of radioisotopes as radiopharmaceuticals. Radiopharmaceuticals are radioactive nuclides and labeled compounds that have been developed for the diagnosis and treatment of (human) disease. They are manufactured via highly controlled processes and have gone through regulatory scrutiny and approval far in excess of other radioisotopes used in other applications. Radiopharmaceuticals can be conveniently split into two categories. One type is simply an active analog that mimics the physiological behavior of its inactive counterpart in the body. The other involves an actual pharmacological compound that exhibits the desired physiological behavior, which is then labeled with a radionuclide suitable for either imaging or the delivery of a therapeutic radiation dose as appropriate but which plays no part in the mechanism of action of the drug. The latter type, which is the more common of the two, can be supplied either as an active compounded product or as a {open_quotes}cold kit,{close_quotes} which is then labeled with the appropriate radiopharmaceutical-grade radionuclide to yield the final product.

Langton, M.A. [Amersham Healthcare, Arlington Heights, IL (United States)

1995-12-31

151

US Department of Energy radioisotope customers with summary of radioisotope shipments, FY 1988  

SciTech Connect

Pacific Northwest Laboratory (PNL) prepared this edition of the radioisotope customer list at the request of the Office of Health and Environmental Research (ER-73), Office of Energy Research, US Department of Energy (DOE). This is the 25th report in a series dating from 1964. This report covers DOE radioisotope sales and distribution activities by its facilities to domestic, foreign and other DOE facilities for FY 1988. The report is divided into five sections: radioisotope suppliers, facility contacts, and radioisotopes or services supplied; a list of customers, suppliers, and radioisotopes purchased; a list of radioisotopes purchased cross-referenced to customer numbers; geographic locations of radioisotope customers; and radioisotope sales and transfers -- FY 1988. Radioisotopes not previously reported in this series of reports were argon-37, arsenic-72, arsenic-73, bismuth-207, gadolinium-151, rhenium-188, rhodium-101, selenium-72, xenon-123 and zirconium-88. The total value of DOE radioisotope sales for FY 1988 was $11.1 million, an increase of 3% from FY 1987.

Van Houten, N.C.

1989-06-01

152

Radioisotopes for radioimmunodetection (RAID) and radioimmunotherapy (RAIT)---current and new perspectives  

SciTech Connect

In this paper the availability and properties of radioisotopes for both radioimmunodiagnosis (RAID) and radioimmunotherapy (RAIT) are discussed. Examples are provided for radioisotopes available via direct production in nuclear reactors and accelerators or as daughters obtained from radionuclide generator systems whose parents are either reactor or accelerator produced. Important factors which must be considered for the use of a particular radioisotope include availability, the physical half-life and decay properties, and chemical versatility for protein attachment. Although both direct'' and indirect'' methods are available for attachment of radioisotopes to antibodies, this broad field of research is not reviewed in detail. Practical issues related to the availability and use of a variety of radionuclides are described. 47 refs., 5 tabs.

Knapp, F.F. Jr.

1991-01-01

153

Radioisotope therapy of cystic craniopharyngeomas  

SciTech Connect

Eighteen patients suffering from cystic craniopharyngeoma were treated with intracavitary irradiation. The beta-emitting radioisotope /sup 90/y (2.25 MeV) was instilled into the cyst following stereotactic puncture of the space-occupying lesion. The surgical approach was planned using angiograms and reconstructed transmission computer tomography (TCT) coronal and saggital sections. Therapy was devised to deliver 20,000 rad to the cyst's wall. Eleven patients received follow-up TCT examinations after four months. Eight of 11 patients had a significant volume decrease in the craniopharyngeoma cyst. In two patients, the cystic volume remained unchanged; one had progression of disease. It is concluded that the intracavitary treatment of cystic craniopharyngeoma will result in a reduction of the size of the space-occupying lesion.

Strauss, L.; Sturm, V.; Georgi, P.; Schlegel, W.; Ostertag, H.; Clorius, J.H.; Van Kaick, G.

1982-09-01

154

Combustion synthesis of novel boron carbide  

NASA Astrophysics Data System (ADS)

The solid-state boron carbide is one of the hardest materials known, ranking third behind diamond and cubic boron nitride. Boron carbide (BxCx) enriched in the 10B isotope is used as a control rod material in the nuclear industry due to its high neutron absorption cross section and other favorable physico-chemical properties. Conventional methods of preparation of boron carbide are energy intensive processes accompanied by huge loss of boron. Attempts were made at IGCAR Kalpakkam to develop energy efficient and cost effective methods to prepare boron carbide. The products of the gel combustion and microwave synthesis experiments were characterized for phase purity by XRD. The carbide formation was ascertained using finger-print spectroscopy of FTIR. Samples of pyrolized/microwave heated powder were characterized for surface morphology using SEM. The present work shows the recent advances in understanding of structural and chemical variations in boron carbide and their influence on morphology, optical and vibrational property results discussed in details.

Harini, R. Saai; Manikandan, E.; Anthonysamy, S.; Chandramouli, V.; Eswaramoorthy, D.

2013-02-01

155

Determination of vanillin in commercial food product by adsorptive stripping voltammetry using a boron-doped diamond electrode.  

PubMed

A method for the determination of food additive vanillin was developed by adsorptive stripping voltammetry. Its determination was carried out at the anodically pre-treated boron-doped diamond electrode in aqueous solutions. Using square-wave stripping mode, the compound yielded a well-defined voltammetric response in phosphate buffer, pH 2.5 at +1.14 V (vs. Ag/AgCl) (a pre-concentration step being carried out at open-circuit condition for 60s). A linear calibration graph was obtained in the concentration range of 0.5-15.0 ?g mL(-1) (3.3×10(-6)-9.8×10(-5) mol L(-1)) with a detection limit of 0.024 ?g mL(-1) (1.6×10(-7) mol L(-1)). As an example, the practical applicability of the proposed method was tested for the determination of this flavouring agent in commercial pudding powder of Keshkule (Turkish milk pudding with almond flour). PMID:23870896

Yard?m, Yavuz; Gülcan, Mehmet; ?entürk, Zühre

2013-05-03

156

List of DOE radioisotope customers with summary of radioisotope shipments, FY 1986  

SciTech Connect

This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1)isotope suppliers, facility contact, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfers for fiscal year 1986.

Lamar, D.A.

1987-10-01

157

Properties of boron/boron-nitride multilayers  

SciTech Connect

Boron-Nitride films are of interest for their high hardness and wear resistance. Large intrinsic stresses and poor adhesion which often accompany high hardness materials can be moderated through the use of a layered structure. Alternate layers of boron (B) and boron-nitride (BN) are formed by modulating the composition of the sputter gas during deposition from a pure B target. The thin films are characterized with TEM to evaluate the microstructure and with nanoindentation to determine hardness. Layer pair spacing and continuity effects on hardness are evaluated for the B/BN films.

Jankowski, A.F.; Wall, M.A.; Hayes, J.P. [Lawrence Livermore National Lab., CA (United States); Alexander, K.B. [Oak Ridge National Lab., TN (United States)

1996-06-01

158

List of DOE radioisotope customers with summary of radioisotope shipments, FY 1984  

SciTech Connect

This edition of the radioisotope customer list was prepared at the request of the Office of Health and Environmental Research (ER-73), Office of Energy Research, Department of Energy (DOE). This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1) isotope suppliers, facility contacts, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfers - FY 1984.

Baker, D.A.

1985-08-01

159

Reliability Issues in Stirling Radioisotope Power Systems.  

National Technical Information Service (NTIS)

Stirling power conversion is a potential candidate for use in a Radioisotope Power System (RPS) for space science missions because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced requirement of radioactive...

A. R. Shah J. G. Schreiber

2004-01-01

160

Reliability Issues in Stirling Radioisotope Power Systems.  

National Technical Information Service (NTIS)

Stirling power conversion is a potential candidate for use in a Radioisotope Power System (RPS) for space science missions because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced requirement of radioactive...

J. Schreiber A. Shah

2005-01-01

161

NASA Radioisotope Power Conversion Technology NRA Overview.  

National Technical Information Service (NTIS)

The focus of the National Aeronautics and Space Administration's (NASA) Radioisotope Power Systems (RPS) Development program is aimed at developing nuclear power and technologies that would improve the effectiveness of space science missions. The Radioiso...

D. J. Anderson

2005-01-01

162

NASA Radioisotope Power Conversion Technology NRA Overview.  

National Technical Information Service (NTIS)

The focus of the National Aeronautics and Space Administration s (NASA) Radioisotope Power Systems (RPS) Development program is aimed at developing nuclear power and technologies that would improve the effectiveness of space science missions. The Radioiso...

D. J. Anderson

2005-01-01

163

Air Transportability of Reactor and Radioisotope Materials.  

National Technical Information Service (NTIS)

A study was made to investigate the prime considerations involved in air transportation of nuclear reactor components, radioactive wastes, and radioisotope powergenerating units. The logistics, economics, and safety of supplying a remote military nuclear ...

J. Fox

1964-01-01

164

Activity calculation of radioisotopes in HFETR.  

National Technical Information Service (NTIS)

The activity calculating method and formulas of seven kinds of radioisotopes for High Flux Engineering Test REactor (HFETR) are given. The perturbation of targets to neutron fluence rate is considered while targets are put into the neutron fluence rate fi...

Liu Shuiqing

1996-01-01

165

Status of the NASA Stirling Radioisotope Project.  

National Technical Information Service (NTIS)

Free-piston Stirling power conversion has been considered a candidate for radioisotope power systems for space for more than a decade. Prior to the free-piston Stirling architecture, systems were designed with kinematic Stirling engines that used linkages...

J. G. Schreiber

2007-01-01

166

Performance tuned radioisotope thermophotovoltaic space power system  

Microsoft Academic Search

The trend in space exploration is to use many small, low-cost, special-purpose satellites instead of the large, high-cost, multipurpose satellites used in the past. As a result of this new trend, there is a need for lightweight, efficient, and compact radioisotope fueled electrical power generators. This paper presents an improved design for a radioisotope thermophotovoltaic (RTPV) space power system in

W. E. Horne; M. D. Morgan; S. B. Saban

1998-01-01

167

Generation of Radioisotopes with Accelerator Neutrons by Deuterons  

NASA Astrophysics Data System (ADS)

A new system proposed for the generation of radioisotopes with accelerator neutrons by deuterons (GRAND) is described by mainly discussing the production of 99Mo used for nuclear medicine diagnosis. A prototype facility of this system consists of a cyclotron to produce intense accelerator neutrons from the \\text{natC(d,n) reaction with 40 MeV 2 mA deuteron beams, and a sublimation system to separate \\text{99mTc from an irradiated 100MoO3 sample. About 8.1 TBq/week of 99Mo is produced by repeating irradiation on an enriched 100Mo sample (251 g) with accelerator neutrons for two days three times. It meets about 10% of the 99Mo demand in Japan. The characteristic feature of the system lies in its capability to reliably produce a wide variety of high-quality, carrier-free, carrier-added radioisotopes with a minimum level of radioactive waste without using uranium. The system is compact in size, and easy to operate; therefore it could be used worldwide to produce radioisotopes for medical, research, and industrial applications.

Nagai, Yasuki; Hashimoto, Kazuyuki; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji; Sato, Nozomi; Kawabata, Masako; Harada, Hideo; Kin, Tadahiro; Tsukada, Kazuaki; Sato, Tetsuya K.; Minato, Futoshi; Iwamoto, Osamu; Iwamoto, Nobuyuki; Seki, Yohji; Yokoyama, Kenji; Shiina, Takehiko; Ohta, Akio; Takeuchi, Nobuhiro; Kawauchi, Yukimasa; Sato, Norihito; Yamabayashi, Hisamichi; Adachi, Yoshitsugu; Kikuchi, Yuji; Mitsumoto, Toshinori; Igarashi, Takashi

2013-06-01

168

Boron-Doped Nanocrystalline Diamond.  

National Technical Information Service (NTIS)

A conductive boron doped nanocrystalline diamond is described. The boron doped diamond has a conductivity which uses the boron in the crystals as a charge carrier. The diamond is particularly useful for electrochemical electrodes in oxidation-reduction re...

G. M. Swain M. Witek P. Sonthalia Y. Show

2004-01-01

169

Hydrodynamics-assisted scalable production of boron nitride nanosheets and their application in improving oxygen-atom erosion resistance of polymeric composites  

NASA Astrophysics Data System (ADS)

Searching for a method for low-cost, easily manageable, and scalable production of boron nitride nanosheets (BNNSs) and exploring their novel applications are highly important. For the first time we demonstrate that a novel and effective hydrodynamics method, which involves multiple exfoliation mechanisms and thus leads to much higher yield and efficiency, can realize large-scale production of BNNSs. The exfoliation mechanisms that multiple fluid dynamics events contribute towards normal and lateral exfoliation processes could be applied to other layered materials. Up to ~95% of the prepared BNNSs are less than 3.5 nm thick with a monolayer fraction of ~37%. Compared to the conventional sonication and ball milling-based methods, the hydrodynamics method has the advantages of possessing multiple efficient ways for exfoliating BN, being low-cost and environmentally-friendly, producing high quality BNNSs in high yield and efficiency, and achieving concentrated BNNSs dispersions even in mediocre solvents. It is also shown for the first time that BNNSs can be utilized as fillers to improve the oxygen-atom erosion resistance of epoxy composites which are widely used for spacecraft in low earth orbit (LEO) where atom oxygen abounds. An addition of only 0.5 wt% BNNSs can result in a 70% decrease in the mass loss of epoxy composites after atom oxygen exposure equivalent to 160 days in an orbit of ~300 km. Overall, the demonstrated hydrodynamics method shows great potential in large-scale production of BNNSs in industry in terms of yield, efficiency, and environmental friendliness; and the innovative application of BNNSs to enhancing oxygen-atom erosion resistance of polymeric composites in space may provide a novel route for designing light spacecraft in LEO.Searching for a method for low-cost, easily manageable, and scalable production of boron nitride nanosheets (BNNSs) and exploring their novel applications are highly important. For the first time we demonstrate that a novel and effective hydrodynamics method, which involves multiple exfoliation mechanisms and thus leads to much higher yield and efficiency, can realize large-scale production of BNNSs. The exfoliation mechanisms that multiple fluid dynamics events contribute towards normal and lateral exfoliation processes could be applied to other layered materials. Up to ~95% of the prepared BNNSs are less than 3.5 nm thick with a monolayer fraction of ~37%. Compared to the conventional sonication and ball milling-based methods, the hydrodynamics method has the advantages of possessing multiple efficient ways for exfoliating BN, being low-cost and environmentally-friendly, producing high quality BNNSs in high yield and efficiency, and achieving concentrated BNNSs dispersions even in mediocre solvents. It is also shown for the first time that BNNSs can be utilized as fillers to improve the oxygen-atom erosion resistance of epoxy composites which are widely used for spacecraft in low earth orbit (LEO) where atom oxygen abounds. An addition of only 0.5 wt% BNNSs can result in a 70% decrease in the mass loss of epoxy composites after atom oxygen exposure equivalent to 160 days in an orbit of ~300 km. Overall, the demonstrated hydrodynamics method shows great potential in large-scale production of BNNSs in industry in terms of yield, efficiency, and environmental friendliness; and the innovative application of BNNSs to enhancing oxygen-atom erosion resistance of polymeric composites in space may provide a novel route for designing light spacecraft in LEO. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03714b

Yi, Min; Shen, Zhigang; Zhang, Wen; Zhu, Jinyang; Liu, Lei; Liang, Shuaishuai; Zhang, Xiaojing; Ma, Shulin

2013-10-01

170

Fabrication of boron articles  

DOEpatents

This invention is directed to the fabrication of boron articles by a powder metallurgical method wherein the articles are of a density close to the theoretical density of boron and are essentially crackfree. The method comprises the steps of admixing 1 to 10 weight percent carbon powder with amorphous boron powder, cold pressing the mixture and then hot pressing the cold pressed compact into the desired article. The addition of the carbon to the mixture provides a pressing aid for inhibiting the cracking of the hot pressed article and is of a concentration less than that which would cause the articles to possess significant concentrations of boron carbide.

Benton, Samuel T. (Knoxville, TN)

1976-01-01

171

Hydrodynamics-assisted scalable production of boron nitride nanosheets and their application in improving oxygen-atom erosion resistance of polymeric composites.  

PubMed

Searching for a method for low-cost, easily manageable, and scalable production of boron nitride nanosheets (BNNSs) and exploring their novel applications are highly important. For the first time we demonstrate that a novel and effective hydrodynamics method, which involves multiple exfoliation mechanisms and thus leads to much higher yield and efficiency, can realize large-scale production of BNNSs. The exfoliation mechanisms that multiple fluid dynamics events contribute towards normal and lateral exfoliation processes could be applied to other layered materials. Up to ?95% of the prepared BNNSs are less than 3.5 nm thick with a monolayer fraction of ?37%. Compared to the conventional sonication and ball milling-based methods, the hydrodynamics method has the advantages of possessing multiple efficient ways for exfoliating BN, being low-cost and environmentally-friendly, producing high quality BNNSs in high yield and efficiency, and achieving concentrated BNNSs dispersions even in mediocre solvents. It is also shown for the first time that BNNSs can be utilized as fillers to improve the oxygen-atom erosion resistance of epoxy composites which are widely used for spacecraft in low earth orbit (LEO) where atom oxygen abounds. An addition of only 0.5 wt% BNNSs can result in a 70% decrease in the mass loss of epoxy composites after atom oxygen exposure equivalent to 160 days in an orbit of ?300 km. Overall, the demonstrated hydrodynamics method shows great potential in large-scale production of BNNSs in industry in terms of yield, efficiency, and environmental friendliness; and the innovative application of BNNSs to enhancing oxygen-atom erosion resistance of polymeric composites in space may provide a novel route for designing light spacecraft in LEO. PMID:24057073

Yi, Min; Shen, Zhigang; Zhang, Wen; Zhu, Jinyang; Liu, Lei; Liang, Shuaishuai; Zhang, Xiaojing; Ma, Shulin

2013-09-23

172

One convenient synthesis route to boron nitride nanotube  

NASA Astrophysics Data System (ADS)

We describe one convenient synthesis route to boron nitride (BN) nanotube by the reaction of boron powder, iron oxide, and ammonium chloride at 600 °C for 12 h. Characterized by XRD, FTIR, XPS, TEM and SAED, the composition and morphology of the products are confirmed. The possible reaction mechanism is also discussed.

Cai, Peijun; Chen, Luyang; Shi, Liang; Yang, Zeheng; Zhao, Aiwu; Gu, Yunle; Huang, Tao; Qian, Yitai

2005-03-01

173

Montan wax improves performance of boron-based wood preservatives  

Microsoft Academic Search

Importance of boron compounds in wood preservation is increasing due to their low environmental impact, high efficacy and the fact that many other active ingredients have been removed from the market after the introduction of the Biocidal Products Directive. The most important drawback of boron is prominent leaching in wet environment. In order to improve their fixation, and performance against

Boštjan Lesar; Polona Kralj; Miha Humar

2009-01-01

174

The influence of isotopically controlled boron addition on void swelling of nickel irradiated in FFTF  

NASA Astrophysics Data System (ADS)

Pure nickel specimens doped with several levels of boron-10 (10B) and natural boron (nB) were irradiated in the Materials Open Test Assembly of the Fast Flux Test Facility (FFTF/MOTA) for the purpose of examining the applicability of boron addition to the study of helium production effects. It was shown that the boron addition enhances void nucleation as its transmulation effect and suppresses as its chemical effect. The former effect is dominant at higher temperatures.

Muroga, T.; Yoshida, N.

1992-09-01

175

High-calcium coal combustion by-products: Engineering properties, ettringite formation, and potential application in solidification and stabilization of selenium and boron  

SciTech Connect

Four high-calcium coal combustion by-products (two pulverized coal fly ashes (PCFA), a flue gas desulfurization (FGD) residue, and an atmospheric fluidized bed combustion (AFBC) fly ash), were tested for engineering properties and ability to immobilize boron and selenium. These data are needed to explore high-volume utilization in engineered structure or in solidification/stabilization (S/S) technology. Strengths of cured pastes (91 days), varied from as much as 27 MPa (3,900 psi) for one of the PCFA specimens to 4.6 MPa (670 psi) for the FGD specimen. All of the coal by-product pastes developed more than the 0.34 MPa (50 psi) required for S/S applications. Ettringite formation is important to engineering properties and S/S mechanisms. XRD on plain specimens cured for 91 days indicated that the two PCFA pastes formed 5--6% ettringite, the FGD paste formed 22%, and the AFBC paste formed 32%. The hydrating PCFA pastes showed little expansion, the FGD paste contracted slightly, and the AFBC paste expanded by 2.9% over 91 days. Se and B were spiked into the mixing water as sodium selenite, selenate and borate, and for most pastes this had little effect on strength, workability, and expansion. Leaching of ground specimens (cured for 91 days) showed a generally positive correlation between the amount of ettringite formed and resistance to Se and B leaching. Se spiked as selenate was more readily leached than Se spiked as selenite. B showed a high level of fixation.

Solem-Tishmack, J.K.; McCarthy, G.J. [North Dakota State Univ., Fargo, ND (United States). Dept. of Chemistry; Docktor, B.; Eylands, K.E.; Thompson, J.S.; Hassett, D.J. [Univ. of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center

1995-04-01

176

Magnetron sputter deposition of boron and boron carbide  

Microsoft Academic Search

The fabrication of x-ray optical coatings with greater reflectivity required the development of sputter deposition processes for boron and boron carbide. The use of high density boron and boron carbide and a vacuum brazed target design was required to achieve the required sputter process stability and resistance to the thermal stress created by high rate sputtering. The results include a

M. A. McKernan; D. Makowiecki; P. Ramsey; A. Jankowski

1991-01-01

177

Guidance for the Reregistration of Pesticide Products Containing Boric Acid and Boron Containing Salts as the Active Ingredient.  

National Technical Information Service (NTIS)

The document contains information regarding the reregistration of pesticide products containing the subject active ingredient. The document includes how to register under a registration standard, regulatory position and rationale, and summaries of data re...

1985-01-01

178

Boron doped graphene nanoribbons  

Microsoft Academic Search

We will present a detailed study of the electronic, magnetic and transport properties of boron doped graphene nanoribbons, for various widths. The electronic structures and the equilibrium geometries were obtained through ab initio total energy DFT calculations. The transport properties were investigated using nonequilibrium Green's functions. Our results reveal that the substitutional boron atoms occupy the edge sites of nanoribbons,

Thiago Martins; Hiroki Miwa; Antonio J. R. da Silva; A. Fazzio

2007-01-01

179

Boron in the Environment  

Microsoft Academic Search

Boron has recently come to the attention of the U.S. Environmental Protection Agency as a possible contaminant worthy of regulation, but questions must still be addressed before a regulatory determination can take place. This article reviews current knowledge about boron as it pertains to water treatment and the environment so that informed decisions can be made regarding regulations and direction

JEFFREY L. PARKS; MARC EDWARDS

2005-01-01

180

ADVANCED RADIOISOTOPE HEAT SOURCE AND PROPULSION SYSTEMS FOR PLANETARY EXPLORATION  

SciTech Connect

The exploration of planetary surfaces and atmospheres may be enhanced by increasing the range and mobility of a science platform. Fundamentally, power production and availability of resources are limiting factors that must be considered for all science and exploration missions. A novel power and propulsion system is considered and discussed with reference to a long-range Mars surface exploration mission with in-situ resource utilization. Significance to applications such as sample return missions is also considered. Key material selections for radioisotope encapsulation techniques are presented.

R. C. O'Brien; S. D. Howe; J. E. Werner

2010-09-01

181

Microwave sintering of boron carbide  

DOEpatents

A method for forming boron carbide into a particular shape and densifying the green boron carbide shape. Boron carbide in powder form is pressed into a green shape and then sintered, using a microwave oven, to obtain a dense boron carbide body. Densities of greater than 95% of theoretical density have been obtained. 1 tab.

Blake, R.D.; Katz, J.D.; Petrovic, J.J.; Sheinberg, H.

1988-06-10

182

Branched polymeric media: boron-chelating resins from hyperbranched polyethylenimine.  

PubMed

Extraction of boron from aqueous solutions using selective resins is important in a variety of applications including desalination, ultrapure water production, and nuclear power generation. Today's commercial boron-selective resins are exclusively prepared by functionalization of styrene-divinylbenzene (STY-DVB) beads with N-methylglucamine to produce resins with boron-chelating groups. However, such boron-selective resins have a limited binding capacity with a maximum free base content of 0.7 eq/L, which corresponds to a sorption capacity of 1.16 ± 0.03 mMol/g in aqueous solutions with equilibrium boron concentration of ?70 mM. In this article, we describe the synthesis and characterization of a new resin that can selectively extract boron from aqueous solutions. We show that branched polyethylenimine (PEI) beads obtained from an inverse suspension process can be reacted with glucono-1,5-D-lactone to afford a resin consisting of spherical beads with high density of boron-chelating groups. This resin has a sorption capacity of 1.93 ± 0.04 mMol/g in aqueous solution with equilibrium boron concentration of ?70 mM, which is 66% percent larger than that of standard commercial STY-DVB resins. Our new boron-selective resin also shows excellent regeneration efficiency using a standard acid wash with a 1.0 M HCl solution followed by neutralization with a 0.1 M NaOH solution. PMID:22827255

Mishra, Himanshu; Yu, Changjun; Chen, Dennis P; Goddard, William A; Dalleska, Nathan F; Hoffmann, Michael R; Diallo, Mamadou S

2012-08-10

183

Boron sorption from aqueous solution by hydrotalcite and its preliminary application in geothermal water deboronation.  

PubMed

Hydrotalcite and its calcination product were used to treat pure water spiked with various concentrations of boron and geothermal water containing boron as a major undesirable element. The kinetics process of boron sorption by uncalcined hydrotalcite is controlled by the diffusion of boron from bulk solution to sorbent-solution boundary film and its exchange with interlayer chloride of hydrotalcite, whereas the removal rate of boron by calcined hydrotalcite rests with the restoration process of its layered structure. The results of isotherm sorption experiments reveal that calcined hydrotalcite generally has much stronger ability to lower solution boron concentration than uncalcined hydrotalcite. The combination of adsorption of boron on the residue of MgO-Al2O3 solid solution and intercalation of boron into the reconstructed hydrotalcite structure due to "structural memory effect" is the basic mechanism based on which the greater boron removal by calcined hydrotalcite was achieved. As 15 geothermal water samples were used to test the deboronation ability of calcined hydrotalcite at 65 °C, much lower boron removal efficiencies were observed. The competitive sorption of the other anions in geothermal water, such as HCO3 (-), SO4 (2-), and F(-), is the reason why calcined hydrotalcite could not remove boron from geothermal water as effectively as from pure boron solution. However, boron removal percents ranging from 89.3 to 99.0 % could be obtained if 50 times of sorbent were added to the geothermal water samples. Calcined hydrotalcite is a good candidate for deboronation of geothermal water. PMID:23695854

Guo, Qinghai; Zhang, Yin; Cao, Yaowu; Wang, Yanxin; Yan, Weide

2013-05-22

184

Overview and Status of NASA's Radioisotope Power Conversion Technology NRA.  

National Technical Information Service (NTIS)

NASA's Advanced Radioisotope Power Systems (RPS) development program is developing next generation radioisotope power conversion technologies that will enable future missions that have requirements that can not be met by either photovoltaic systems or by ...

D. J. Anderson K. L. Tuttle W. A. Wong

2005-01-01

185

Process for producing wurtzitic or cubic boron nitride  

DOEpatents

Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described.

Holt, J.B.; Kingman, D.D.; Bianchini, G.M.

1992-04-28

186

Process for producing wurtzitic or cubic boron nitride  

DOEpatents

Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described.

Holt, J. Birch (San Jose, CA); Kingman, deceased, Donald D. (late of Danville, CA); Bianchini, Gregory M. (Livermore, CA)

1992-01-01

187

Observing Boron in Metal-Poor Stars  

NASA Astrophysics Data System (ADS)

By combining information on the abundances of the light elements, lithium, beryllium, and boron, in the same stars, a more consistent picture of their production, evolution, and depletion can be achieved. The analysis of the boron spectral region (2500 AA) in a new sample of stars, for which Li and Be abundances had already been measured, is presented. Special attention is devoted to discuss the associated uncertainties and to estimate the accuracy achievable when measuring boron. These new 6 data points enlarge by almost 50% our previous B sample (cf Duncan et al. 1997), and give us the opportunity to draw firmer conclusions as far as production mechanisms and evolutionary history are concerned. Our simultaneous knowledge of LiBeB for all the targets is a powerful diagnostic for testing depletion and internal mixing predicted by different stellar structure models.

Primas, F.

188

NASA's Advanced Radioisotope Power Conversion Technology Development Status  

Microsoft Academic Search

NASA's Advanced Radioisotope Power Systems (ARPS) project is developing the next generation of radioisotope power conversion technologies that will enable future missions that have requirements that cannot be met by either photovoltaic systems or by current radioisotope power systems (RPSs). Requirements of advanced RPSs include high efficiency and high specific power (watts\\/kilogram) in order to meet future mission requirements with

David J. Anderson; John Sankovic; David Wilt; Robert D. Abelson; Jean-Pierre Fleurial

2007-01-01

189

Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission  

Microsoft Academic Search

The preceding paper (Schock 1994) described conceptual designs and analytical results for five Radioisotope Thermoelectric Generator (RTG) options for the Pluto Fast Flyby (PFF) mission, and the present paper describes three Radioisotope Stirling Generator (RSG) options for the same mission. The RSG options are based on essentially the same radioisotope heat source modules used in previously flown RTGs and on

Alfred Schock

1994-01-01

190

Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission  

Microsoft Academic Search

The preceding paper described conceptual designs and analytical results for five Radioisotope Thermoelectric Generator (RTG) options for the Pluto Fast Flyby (PFF) mission, and the present paper describes three Radioisotope Stirling Generator (RSG) options for the same mission. The RSG options are based on essentially the same radioisotope heat source modules used in previously flown RTGs and on designs and

Schock

2012-01-01

191

RADIOISOTOPES IN THE STUDY OF BONE  

Microsoft Academic Search

ABS>The use of two groups of radioisotopes in bone research is ; discussed: the alkaline earth elements, such as Ra and Sr, which are taken up ; like Ca in centers of growing bone; and rare earth elements, such as Y and Pu, ; which are stored in bone. The physiologic factors underlying uptake of this ; second group are

F. C. McLean; A. M. Budy

1962-01-01

192

NASA Radioisotope Power Systems Program Update  

Microsoft Academic Search

The use of Radioisotope Power Systems (RPS) represents a critical capability for exploration of the Solar System. RPS have been used for decades to power deep space missions and sometimes for the operation of landers or rovers on Mars. Modest power needs (5 AU) make them attractive, and, in most cases,

B. Alan Harmon; David B. Lavery

2008-01-01

193

NASA Radioisotope Power Systems Program Update  

Microsoft Academic Search

The use of Radioisotope Power Systems (RPS) represents a critical capability for exploration of the Solar System. RPS have been used for decades to power deep space missions and sometimes for the operation of landers or rovers on Mars. Modest power needs (5 AU) make them attractive, and, in most cases, essential for a variety of missions. Even close by,

B. Alan Harmon; David B. Lavery

2008-01-01

194

ILLUSTRATIONS OF RADIOISOTOPES--DEFINITIONS AND APPLICATIONS.  

ERIC Educational Resources Information Center

|THIS PUBLICATION IS COMPOSED OF OVER 150 PAGES OF BLACK AND WHITE ILLUSTRATIONS DEALING WITH RADIOISOTOPES AND THEIR USES. THESE ILLUSTRATIONS CONSIST OF CHARTS, GRAPHS, AND PICTORIAL REPRESENTATIONS WHICH COULD BE PREPARED AS HANDOUTS, TRANSPARENCIES FOR OVERHEAD PROJECTION, OR WHICH COULD BE USED IN A NUMBER OF OTHER WAYS FOR PRESENTING SUCH…

Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

195

NASA Radioisotope Power Conversion Technology NRA Overview  

NASA Astrophysics Data System (ADS)

The focus of the National Aeronautics and Space Administration's (NASA) Radioisotope Power Systems (RPS) Development program is aimed at developing nuclear power and technologies that would improve the effectiveness of space science missions. The Radioisotope Power Conversion Technology (RPCT) NASA Research Announcement (NRA) is an important mechanism through which research and technology activities are supported in the Advanced Power Conversion Research and Technology project of the Advanced Radioisotope Power Systems Development program. The purpose of the RPCT NRA is to advance the development of radioisotope power conversion technologies to provide higher efficiencies and specific powers than existing systems. These advances would enable a factor of 2 to 4 decrease in the amount of fuel and a reduction of waste heat required to generate electrical power, and thus could result in more cost effective science missions for NASA. The RPCT NRA selected advanced RPS power conversion technology research and development proposals in the following three areas: innovative RPS power conversion research, RPS power conversion technology development in a nominal 100We scale; and, milliwatt/multi-watt RPS (mWRPS) power conversion research. Ten RPCT NRA contracts were awarded in 2003 in the areas of Brayton, Stirling, thermoelectric (TE), and thermophotovoltaic (TPV) power conversion technologies. This paper will provide an overview of the RPCT NRA, a summary of the power conversion technologies approaches being pursued, and a brief digest of first year accomplishments.

Anderson, David J.

2005-02-01

196

Development of a radioisotope heat source for the two-watt radioisotope thermoelectric generator  

Microsoft Academic Search

Described is a radioisotope heat source for the Two-Watt Radioisotope Thermoelectric Generator (RTG) which is being considered for possible application by the U.S. Navy and for other Department of Defense applications. The heat source thermal energy (75 Wt) is produced from the alpha decay of plutonium-238 which is in the form of high-fired plutonium dioxide. The capsule is non-vented and

Edwin I. Howell; Dennis C. McNeil; Wayne R. Amos

1992-01-01

197

Direct current sputtering of boron from boron/coron mixtures  

DOEpatents

A method for coating a substrate with boron by sputtering includes lowering the electrical resistance of a boron-containing rod to allow electrical conduction in the rod; placing the boron-containing rod inside a vacuum chamber containing substrate material to be coated; applying an electrical potential between the boron target material and the vacuum chamber; countering a current avalanche that commences when the conduction heating rate exceeds the cooling rate, and until a steady equilibrium heating current is reached; and, coating the substrate material with boron by sputtering from the boron-containing rod.

Timberlake, John R. (Allentown, NJ); Manos, Dennis (Williamsburg, VA); Nartowitz, Ed (Edison, NJ)

1994-01-01

198

Direct current sputtering of boron from boron/carbon mixtures  

DOEpatents

A method for coating a substrate with boron by sputtering includes lowering the electrical resistance of a boron-containing rod to allow electrical conduction in the rod; placing the boron-containing rod inside a vacuum chamber containing substrate material to be coated; applying an electrical potential between the boron target material and the vacuum chamber; countering a current avalanche that commences when the conduction heating rate exceeds the cooling rate, and until a steady equilibrium heating current is reached and coating the substrate material with boron by sputtering from the boron-containing rod.

Timberlake, J.R.; Manos, D.; Nartowitz, E.

1993-12-31

199

Development of Next Generation Segmented Thermoelectric Radioisotope Power Systems  

NASA Astrophysics Data System (ADS)

Radioisotope thermoelectric generators have been used for space-based applications since 1961 with a total of 22 space missions that have successfully used RTGs for electrical power production. The key advantages of radioisotope thermoelectric generators (RTGs) are their long life, robustness, compact size, and high reliability. Thermoelectric converters are easily scalable, and possess a linear current-voltage curve, making power generation easy to control via a shunt regulator and shunt radiator. They produce no noise, vibration or torque during operation. These properties have made RTGs ideally suitable for autonomous missions in the extreme environments of outer space and on planetary surfaces. More advanced radioisotope power systems (RPS) with higher specific power (W/kg) and/or power output are desirable for future NASA missions, including the Europa Geophysical Orbiter mission. For the past few years, the Jet Propulsion Laboratory (JPL) has been developing more efficient thermoelectric materials and has demonstrated significant increases in the conversion efficiency of high temperature thermocouples, up to 14% when operated across a 975K to 300K temperature differential. In collaboration with NASA Glenn Research Center, universities (USC and UNM), Ceramic and Metal Composites Corporation and industrial partners, JPL is now planning to lead the research and development of advanced thermoelectric technology for integration into the next generations of RPS. Preliminary studies indicate that this technology has the potential for improving the RPS specific power by more than 50% over the current state-of-the-art multi-mission RTG being built for the Mars Science Laboratory mission. A second generation advanced RPS is projected at more than doubling the specific power.

Fleurial, J.; Caillat, T.; Ewell, R. C.

2005-12-01

200

Chemical disposition of boron in animals and humans.  

PubMed Central

Elemental boron was isolated in 1808. It typically occurs in nature as borates hydrated with varying amounts of water. Important compounds are boric acid and borax. Boron compounds are also used in the production of metals, enamels, and glasses. In trace amounts, boron is essential for the growth of many plants, and is found in animal and human tissues at low concentrations. Poisoning in humans has been reported as the result of accidental ingestion or use of large amounts in the treatment of burns. Boron as boric acid is fairly rapidly absorbed and excreted from the body via urine. The half-life of boric acid in humans is on the order of 1 day. Boron does not appear to accumulate in soft tissues of animals, but does accumulate in bone. Normal levels of boron in soft tissues, urine, and blood generally range from less than 0.05 ppm to no more than 10 ppm. In poisoning incidents, the amount of boric acid in brain and liver tissue has been reported to be as high as 2000 ppm. Recent studies at the National Institute of Environmental Health Sciences have indicated that boron may contribute to reduced fertility in male rodents fed 9000 ppm of boric acid in feed. Within a few days, boron levels in blood and most soft tissues quickly reached a plateau of about 15 ppm. Boron in bone did not appear to plateau, reaching 47 ppm after 7 days on the diet. Cessation of exposure to dietary boron resulted in a rapid drop in bone boron.(ABSTRACT TRUNCATED AT 250 WORDS)

Moseman, R F

1994-01-01

201

An introduction to boron: history, sources, uses, and chemistry.  

PubMed Central

Following a brief overview of the terrestrial distribution of boron in rocks, soil, and water, the history of the discovery, early utilization, and geologic origin of borate minerals is summarized. Modern uses of borate-mineral concentrates, borax, boric acid, and other refined products include glass, fiberglass, washing products, alloys and metals, fertilizers, wood treatments, insecticides, and microbiocides. The chemistry of boron is reviewed from the point of view of its possible health effects. It is concluded that boron probably is complexed with hydroxylated species in biologic systems, and that inhibition and stimulation of enzyme and coenzymes are pivotal in its mode of action. Images Figure 1.

Woods, W G

1994-01-01

202

Molecular Structure of boron  

NSDL National Science Digital Library

Boron was founded in 1808 by Sir Humphry Davy and Gay-Lussac and Thenard. It occurs as orthoboric acid in volcanic spring waters and as borates in Boron and colematic. Some sources can also be found in the Mohave Desert. It is used when making glass to keep the glass from breaking under temperature stress. Also if combined with sodium hydroxide and hydrogen peroxide it makes bleach.

2002-08-26

203

Boron and Plants  

Microsoft Academic Search

\\u000a Boron is found naturally in the earth’s crust in the oxidized form as borax and colemanite, particularly in the oceans, sedimentary\\u000a rocks, coal, shale, and some soils. It is never found in the elemental form in nature possessing a complex chemistry similar\\u000a to that of silicon, with properties switching between metals and non-metals. Boron has become an important and strategic

Munir Ozturk; Serdal Sakcali; Salih Gucel; Huseyin Tombuloglu

204

Removal of Boron from Silicon by Moist Hydrogen Gas  

NASA Astrophysics Data System (ADS)

New and cheaper refining methods for production of metallurgical silicon are needed to meet the increasing demands for low-cost, high-quality silicon for the solar cell industry. One promising refining method for boron is moist hydrogen treatment. In this work, an evaporation unit has been used to produce wet hydrogen gas, which subsequently has been sparged on top of silicon melts. The effect of temperature and gas composition on boron removal has been studied. The main results show that boron is removed from liquid silicon and the removal rate is controlled by chemical reaction depending on p_{{{{H}}_{ 2} {{O}}}} and p_{{{{H}}_{ 2} }} . Water vapor treatment of molten silicon can alone remove boron. However, in combination with hydrogen gas, the removal rate is significantly increased. In addition, the rate of boron removal in silicon has been found to decease with increasing temperature.

Nordstrand, Erlend F.; Tangstad, Merete

2012-08-01

205

Micronized wood preservative formulations comprising boron compounds  

US Patent & Trademark Office Database

The present invention provides wood preservative and flame retardant compositions having low leachability comprising micronized boron compounds and, optionally, one or more organic biocides which may be micronized. Also provided is a method for applying the composition to wood and wood products comprising impregnating the wood with the composition.

Zhang; Jun (Getzville, NY); Zhang; Wenjin (Tonawanda, NY); Leach; Robert M. (Grand Island, NY)

2012-05-01

206

Risk assessment of boron in glass wool insulation  

Microsoft Academic Search

Background, aim and scope  Glass wools are man-made vitreous fibres, which consist principally of sodium, calcium and magnesium silicates, but may contain\\u000a smaller amounts of other elements, including boron. The boron contents originate from the use of borates in the glass melting\\u000a process as a glass former and a flux agent. During the production and application of glass wool insulation products,

Allan Astrup Jensen

2009-01-01

207

Particle-beam accelerators for radiotherapy and radioisotopes  

SciTech Connect

The philosophy used in developing the new PIGMI technology was that the parameters chosen for physics research machines are not necessarily the right ones for a dedicated therapy or radioisotope machine. In particular, the beam current and energy can be optimized, and the design should emphasize minimum size, simplicity and reliability of operation, and economy in capital and operating costs. A major part of achieving these goals lay in raising the operating frequency and voltage gradient of the accelerator, which shrinks the diameter and length of the components. Several other technical innovations resulted in major system improvements. One of these is a radically new type of accelerator structure named the radio-frequency quadrupole (RFQ) accelerator. This allowed us to eliminate the large, complicated ion source used in previous ion accelerators, and to achieve a very high quality accelerated beam. Also, by using advanced permanent magnet materials to make the focusing elements, the system becomes much simpler. Other improvements have been made in all of the accelerator components and in the methods for operating them. These will be described, and design and costing information examples given for several possible therapy and radioisotope production machines.

Boyd, T.J.; Crandall, K.R.; Hamm, R.W.

1981-01-01

208

An overview of the Radioisotope Thermoelectric Generator Transportation System Program  

SciTech Connect

Radioisotope Thermoelectric Generators (RTG) convert the heat generated by radioactive decay to electricity using thermocouples. RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance once assembled and tested. These factors make RTGs particularly attractive for use in spacecraft. However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they must be transported in packages built in accordance with Title 10, Code of Federal Regulations, Part 71. The U.S. Department of Energy assigned the Radioisotope Thermoelectric Generator Transportation System (RTGTS) Program to Westinghouse Hanford Company in 1988 to develop a system meeting the regulatory requirements. The program objective was to develop a transportation system that would fully comply with 10 CFR 71 while protecting RTGs from adverse environmental conditions during normal conditions of transport (e.g., shock and heat). The RTGTS is scheduled for completion in December 1996 and will be available to support the National Aeronautics and Space Administration{close_quote}s Cassini mission to Saturn in October 1997. This paper provides an overview of the RTGTS and discusses the hardware being produced. Additionally, various program management innovations mandated by recent major changes in the U.S. Department of Energy structure and resources will be outlined. {copyright} {ital 1996 American Institute of Physics.}

McCoy, J.C.; Becker, D.L. [Westinghouse Hanford Company, P.O. Box 1970, Richland, Washington 99352 (United States)

1996-03-01

209

An overview of the Radioisotope Thermoelectric Generator Transporation System Program  

SciTech Connect

Radioisotope Thermoelectric Generators (RTG) convert the heat generated by radioactive decay to electricity using thermocouples. RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance once assembled and tested. These factors make RTGs particularly attractive for use in spacecraft However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they must be transported in packages built in accordance with Title 10, Code of Federal Regulations, Part 71. The US Department of Energy assigned the Radioisotope Thermoelectric Generator Transportation System (RTGTS) Program to Westinghouse Hanford Company in 1988 to develop a system meeting the regulatory requirements. The program objective was to develop a transportation system that would fully comply with 10 CFR 71 while protecting RTGs from adverse environmental conditions during normal conditions of transport (e.g., shock and heat). The RTGTS is scheduled for completion in December 1996 and will be available to support the National Aeronautics and Space Administrations Cassini mission to Saturn in October 1997. This paper provides an overview of the RTGTS and discusses the hardware being produced. Additionally, various program management innovations mandated by recent ma or changes in the US Department of Energy structure and resources will be outlined.

McCoy, J.C.

1995-10-01

210

Boron and lithium isotopic composition in chondrules from the mokoia meteorite  

NASA Astrophysics Data System (ADS)

Introduction: Large Boron isotopic variations have been reported in individual chondrules from several meteorites [1, 2]. These variations were interpreted as resulting from the incomplete mixing of two isotopically distinct sources of Boron. Spallation is the only known nucleosynthetic process that can yield Boron in substantial amounts at the scale of the Universe. Therefore it has been proposed that the two sources observed in chondrules correspond to two different types of spallation reactions, namely at high and low energies. Indeed, in the case of Boron, the 11B/10B ratio is sensitive to the energy at which the spallation reaction takes place. Since this report of large B isotopic variations in chondrules, two observations have allowed to identify the natural conditions under which at least one of such spallation reactions may have taken place in the early solar system. First, X-ray observations of T-Tauri stars have revealed daily outbursts which mimic the present day solar activity during the emission of flares [3]. Second, the decay product (i.e. 10B) of the short lived radio-isotope 10Be was discovered in Calcium-Aluminum-rich inclusions (CAIs) [4]. This is an indication that spallation did occurr in the solar system, shortly (i.e. less than a few million years) before the formation of the CAIs. In addition the possible occurrence of 7Be in CAIs suggests that this duration can be as short as a few months [5]. Sampling and Results: In the 8 chondrules from Mokoia, the ?11B values range between -39±6.8 ppm and -0.6±7.8 ppm (2 sigma). In one Boron depleted area of one chondrule, the ?11B value was found to be as low as -68.5 ppm and -61.5 ppm (±29; 2 sigma). In one chondrule from Mokoia the ?11B values range between -33.7±5.4 ppm and -3.8±5.4 ppm. These data confirm with a resolution of ? ±6 ppm the presence of a significant Boron isotopic heterogeneity,.The ?^7Li were also measured along with the ^delta11B. They range from -53.7±2.4 and -0.15±1.6 ppm (2 sigma) in the 8 chondrules of the Mokoia meteorite. Therefore the heterogeneity in B has its counterpart for Li. Interpretation: A two end member mixing model members can be proposed : ?11B ?0 ppm and ?11B<= -70 ppm. The value of 0 ppm is still significantly different from the matrix value reported by [6] (+19.2 ppm) and thus the possible contamination of the chondrule by their surrounding matrix is highly unlikely. The second end member should have ?11B and ?^7Li values le-70 ppm and le-50 ppm, respectively, resulting from Li and B produced at high energy by spallation reactions (E >= 100 MeV/nucleon, ?11B =-375 ?^7Li = -830 ppm). References: [1] Chaussidon M., Robert F. (1995) Nature 374, 337-339. [2] Chaussidon M. and Robert F. (1998) Earth Planet Sci. Lett. 164, 577-589. [3] Montmerle T. (1999) MPE Report : Astronomy with Radioactivities, 225-236. [4] McKeegan K., Chaussidon M., Robert F. (2000) Science 289, 1334-1337. [5] Chaussidon M., Robert F. McKeegan K. (2002) Abst. 33th LPSC #1563 [6] Hoppe et al., (2001) MAPS, 36, 1331-1343. [7] Zhai M et al., (1996) Geochim. Cosmochim. Acta 60, 4877-4881.

Robert, F.; Chaussidon, M.

2003-04-01

211

Electrochemical oxidation of benzoic acid in water over boron-doped diamond electrodes: Statistical analysis of key operating parameters, kinetic modeling, reaction by-products and ecotoxicity  

Microsoft Academic Search

The electrochemical oxidation of benzoic acid over boron-doped diamond electrodes was studied. Experiments were conducted in a flow-through electrolytic cell at current intensities ranging from 11 to 24A, an electrolyte concentration of 0.05M and initial substrate concentrations ranging from 16 to 185mg L?1. Liquid chromatography (LC) coupled to diode array detector was employed to follow benzoic acid concentration profiles, while

Theodora Velegraki; George Balayiannis; Evan Diamadopoulos; Alexandros Katsaounis; Dionissios Mantzavinos

2010-01-01

212

LightWeight Radioisotope Heater Unit  

Microsoft Academic Search

DOE is developing a new generation of radioisotope-fueled 1-watt heaters, for initial use on NASA's upcoming Galileo and International Solar-Polar Missions. Each heater must contain passive safety provisions to ensure fuel retention under all credible accident conditions. Initial design reviews raised some concern about the accuracy of the predicted peak reenetry temperature, and about the adequacy of the safety margin

Schock

1981-01-01

213

Boron Hydride Polymer Coated Substrates.  

National Technical Information Service (NTIS)

A method is disclosed for coating a substrate with a uniformly smooth layer of a boron hydride polymer. The method comprises providing a reaction chamber which contains the substrate and the boron hydride plasma. A boron hydride feed stock is introduced i...

R. K. Pearson R. I. Bystroff D. E. Miller

1986-01-01

214

Production of exp 192 Ir Sources for Radiotherapy.  

National Technical Information Service (NTIS)

Radiation sources of exp 192 Ir for cancer therapy were developed in the Division of Radioisotope Production, Radioisotope Center, Japan Atomic Energy Research Institute (JAERI). ''Hairpin'', ''Single-pin'' and ''Seed'' have been produced since October 19...

A. Sato H. Kogure H. Kato

1981-01-01

215

In Vivo Boron Uptake Determination for Boron Neutron Capture Synovectomy  

SciTech Connect

Boron neutron capture synovectomy (BNCS) has been proposed as a new application of the boron neutron capture reaction for the treatment of rheumatoid arthritis. In BNCS, a boron compound is injected into the joint space, where it is taken up by the synovium. The joint is then irradiated with neutrons of a desired energy range, inducing the boron neutron capture reaction in boron-loaded cells. Boron uptake by the synovium is an important parameter in the assessment of the potential of BNCS and in the determination of whether to proceed to animal irradiations for the testing of therapeutic efficacy. We present results from an investigation of boron uptake in vivo by the synovium.

Binello, Emanuela; Shortkroff, Sonya; Yanch, Jacquelyn C.

1999-06-06

216

Boron Requirement in Cyanobacteria 1  

PubMed Central

The effect of boron on heterocystous and nonheterocystous dinitrogen fixing Cyanobacteria was examined. The absence of boron in culture media inhibited growth and nitrogenase activity in Nodularia sp., Chlorogloeopsis sp., and Nostoc sp. cultures. Examinations of boron-deficient cultures showed changes in heterocyst morphology. However, cultures of nonheterocystous Cyanobacteria, Gloeothece sp. and Plectonema sp., grown in the absence of boron did not show any alteration in growth or nitrogenase activity. These results suggest a requirement of boron only by heterocystous Cyanobacteria. A possible role for this element in the early evolution of photosynthetic organisms is proposed. Images Figure 4 Figure 5 Figure 6

Bonilla, Ildefonso; Garcia-Gonzalez, Mercedes; Mateo, Pilar

1990-01-01

217

Boron hydride polymer coated substrates  

DOEpatents

A method is disclosed for coating a substrate with a uniformly smooth layer of a boron hydride polymer. The method comprises providing a reaction chamber which contains the substrate and the boron hydride plasma. A boron hydride feed stock is introduced into the chamber simultaneously with the generation of a plasma discharge within the chamber. A boron hydride plasma of ions, electrons and free radicals which is generated by the plasma discharge interacts to form a uniformly smooth boron hydride polymer which is deposited on the substrate.

Pearson, Richard K. (Pleasanton, CA); Bystroff, Roman I. (Livermore, CA); Miller, Dale E. (Livermore, CA)

1987-01-01

218

Boron hydride polymer coated substrates  

DOEpatents

A method is disclosed for coating a substrate with a uniformly smooth layer of a boron hydride polymer. The method comprises providing a reaction chamber which contains the substrate and the boron hydride plasma. A boron hydride feed stock is introduced into the chamber simultaneously with the generation of a plasma discharge within the chamber. A boron hydride plasma of ions, electrons and free radicals which is generated by the plasma discharge interacts to form a uniformly smooth boron hydride polymer which is deposited on the substrate.

Pearson, R.K.; Bystroff, R.I.; Miller, D.E.

1986-08-27

219

Specific radioisotopic assay for cholinesterase  

SciTech Connect

The authors have developed a radiometric method (1) for measuring cholinesterase (ChE) activity that uses 0.4 N perchloric acid (PCA), instead of p-dioxane (method 2), to denature the ChE and stop hydrolysis of acetyl-1-{sup 14}C-choline (ACh). The unreacted ACh is removed by IRP-69 cationic exchange resin suspended in water, instead of dioxane. The supernatant containing the hydrolysis product, {sup 14}C-acetic acid, is mixed with nonhazardous scintillation cocktail and counted. The incubation mixture of 1 is similar to 2 and contains 0.1 ml of buffer-salt solution 0.1 ml of guinea pig whole blood (WB)-water suspension and 0.1 ml of 3 mM ACh solution. Procedures 1 and 2 were compared to a titragraphic assay for ChE activity; specific activity values of WB (mmol ACh hydrolyzed/ml/hr) were found to be 137.6, 72.4 and 135.0, respectively. When {sup 14}C-acetic acid was processed through procedures 1 and 2, significantly less {sup 14}C was found in the supernatant from 2, whereas all of the expected {sup 14}C was found in the supernatant from 1, suggesting that IRP-69 resin in dioxane will remove significant amounts of {sup 14}C-acetic acid.

Talbot, B.G.; Anderson, D.R.; Harris, L.W.; Lennox, W.J. (Army Medical Research Inst., Aberdeen Proving Ground, MD (United States))

1992-02-01

220

Fabrication of boron sputter targets  

DOEpatents

A process for fabricating high density boron sputtering targets with sufficient mechanical strength to function reliably at typical magnetron sputtering power densities and at normal process parameters. The process involves the fabrication of a high density boron monolithe by hot isostatically compacting high purity (99.9%) boron powder, machining the boron monolithe into the final dimensions, and brazing the finished boron piece to a matching boron carbide (B.sub.4 C) piece, by placing aluminum foil there between and applying pressure and heat in a vacuum. An alternative is the application of aluminum metallization to the back of the boron monolithe by vacuum deposition. Also, a titanium based vacuum braze alloy can be used in place of the aluminum foil.

Makowiecki, Daniel M. (Livermore, CA); McKernan, Mark A. (Livermore, CA)

1995-01-01

221

The role of hydrothermal fluids in the production of subduction zone magmas: Evidence from siderophile and chalcophile trace elements and boron  

NASA Astrophysics Data System (ADS)

In order to evaluate the processes responsible for the enrichments of certain siderophile/ chalcophile trace elements during the production of subduction-related magmas, representative lavas from seven subduction zones have been analyzed for Pb, As, Sb, Sn, W, Mo, Tl, Cu, and Zn by inductively coupled plasma-mass spectrometry (ICP-MS), radiochemical epithermal neutron activation analysis (RENA), and atomic absorption (AA). The siderophile/chalcophile elements are compared to the highly fluid-mobile element B, the light rare earth elements (LREEs), U, and Th in order to place constraints on their behavior in subduction zones. Boron, As, Sb, and Pb are all enriched in arc lavas and continental crustal rocks more so than expected assuming normal magmatic processes (melting and crystallization). Tin, W, and Mo show little evidence of enrichment. Correlations of Pb/Ce, As/Ce, and Sb/Ce with B/La are statistically significant and have high correlation coefficients (and, more importantly, slopes approaching one) suggesting that Pb, As, and Sb behave similarly to B (i.e., that they are fluid-mobile). In addition, across-arc traverses show that B/La, As/Ce, Pb/Ce, and Sb/Ce ratios decrease dramatically with distance towards the back-arc basin. W/Th, Tl/La, Sn/Sm, and Mo/Ce ratios and Cu and Zn concentrations have much less systematic across-arc variations and correlations with B/La are not as strong (and in some cases, not statistically significant) and the regression lines have much lower slopes. Mixing models between upper mantle, slab-derived fluid, and sediment are consistent with a fluid-derived component in the arcs displaying extra enrichments of B, Pb, As, and Sb. These observations imply efficient mobilization of B, Pb, As, Sb, and possibly Tl into arc magma source regions by hydrothermal fluids derived from metamorphic dehydration reactions within the slab. Tin, W, and Mo show little, if any, evidence of hydrothermal mobilization. Copper appears to be slightly enriched in arc lavas relative to mid-ocean ridge basalts (MORBs) whereas Zn contents of arc lavas, MORB, ocean island basalts (OIBs), and continental crustal samples are similar suggesting that the bulk partition coefficient for Zn is approximately equal to one. However, Zn contents of the upper mantle are lower than these reservoirs implying an enrichment of the source region in Zn prior to melting. These nonigneous enrichments have implications not only for arc magma genesis but also for continental crust formation and crust-mantle evolution. The mobility of Pb, As, Sb, and B in hot, reducing, acidic hydrothermal fluids may be greatly enhanced relative to the large-ion lithophile elements (LILEs; including U) as a result of HS-, H2S, OH-, or other types of complexing. In the case of Pb, continued transport of Pb from subducted slabs into arc magma source regions throughout Earth history coupled with a U fluxing of the mantle a the end of the Archean may account for the depletion of Pb in the upper mantle, the low U/Pb of most arc volcanics and continental crustal rocks, and provide an explanation for the Pb- Paradox (Hofmann et al., 1986;McCulloch, 1993;Miller et al., 1994). Recycled slabs will then retain high U/Pb ratios upon entering the deep mantle and may eventually become incorporated into the source regions of many OIBs; some with HIMU (high 238U/204Pb) signatures.

Noll, P. D.; Newsom, H. E.; Leeman, W. P.; Ryan, J. G.

1996-02-01

222

Plasma boron and the effects of boron supplementation in males.  

PubMed Central

Recently, a proliferation of athletic supplements has been marketed touting boron as an ergogenic aid capable of increasing testosterone. The effect of boron supplementation was investigated in male bodybuilders. Ten male bodybuilders (aged 20 to 26) were given a 2.5-mg boron supplement, while nine male bodybuilders (aged 21 to 27) were given a placebo for 7 weeks. Plasma total and free testosterone, plasma boron, lean body mass, and strength measurements were determined on day 1 and day 49 of the study. A microwave digestion procedure followed by inductively coupled argon plasma spectroscopy was used for boron determination. Twelve subjects had boron values at or above the detection limit with median value of 25 ng/ml (16 ng/ml lower quartile and 33 ng/ml upper quartile). Of the ten subjects receiving boron supplements, six had an increase in their plasma boron. Analysis of variance indicated no significant effect of boron supplementation on any of the other dependent variables. Both groups demonstrated significant increases in total testosterone (p < 0.01), lean body mass (p < 0.01), and one repetition maximum (RM) squat (p < 0.001) and one RM bench press (p < 0.01). The findings suggest that 7 weeks of bodybuilding can increase total testosterone, lean body mass, and strength in lesser-trained bodybuilders, but boron supplementation affects these variables not at all.

Green, N R; Ferrando, A A

1994-01-01

223

Daily Boron Intake from the American Diet  

Microsoft Academic Search

Interest in boron as a naturally occurring trace element nutrient from the food supply is increasing. Mounting evidence suggests that boron is essential to human beings. This study explores the major food and beverage contributors of boron and estimates of daily boron intake from the American diet. Previous estimates in the literature of dietary boron consumption are based on limited

CHARLENE J RAINEY; LESLIE A NYQUIST; ROBERT E CHRISTENSEN; PHILIP L STRONG; B DWIGHT CULVER; JAMES R COUGHLIN

1999-01-01

224

Wettability of Boron Carbide.  

National Technical Information Service (NTIS)

The work was presented at the conference, Advanced Joining Technologies from New Materials II, which was held in Cocoa Beach, USA, 2-4th of March. The conference proceedings will be published in 1994. The wettability of boron carbide has been examined by ...

T. Torvund O. M. Akselsen O. Grong J. H. Ulvensoen

1994-01-01

225

Sublimation of Boron.  

National Technical Information Service (NTIS)

Torsion-effusion and mass spectrometric techniques were used to study the vaporization of beta -rhombohedral boron over the temperature range 1823 to 2253 exp 0 K. The pressure-temperature data were fitted by the equation ln P(Pa) = -(66.8 +- 1.4) 10 exp ...

R. W. Mar R. G. Bedford

1976-01-01

226

Radioisotope Micropower System Using Thermophotovoltaic Energy Conversion  

NASA Astrophysics Data System (ADS)

Recent advances in thermophotovoltaic (TPV) energy conversion efficiency have increased interest in investigating the use of TPV in a wider spectrum of applications. This paper discusses a micropower system under development that utilizes a radioisotope heat source, microelectromechanical (MEM) thermal insulation, 3-D tungsten photonic crystal (PC) emitter, and thermophotovoltaic modules for the energy conversion. The 3-D tungsten photonic crystal (PC) emitter is a selective emitter that is designed to match the bandgap of the TPV module. Compared to bulk tungsten, the PC has increased emittance in the convertible wavelength range and decreased emittance in the nonconvertible wavelength range, which results in a greater than 10% improvement in conversion efficiency.

Koudelka, Robert D.; Murray, Christopher S.; Fleming, James G.; Shaw, Michael J.; Teofilo, Vince; Alexander, Charles

2006-01-01

227

Radioisotope microbattery based on liquid semiconductor  

NASA Astrophysics Data System (ADS)

A liquid semiconductor-based radioisotope micropower source has been pioneerly developed. The semiconductor property of selenium was utilized along with a 166 MBq radioactive source of 35S as elemental sulfur. Using a liquid semiconductor-based Schottky diode, electrical power was distinctively generated from the radioactive source. Energetic beta radiations in the liquid semiconductor can produce numerous electron hole pairs and create a potential drop. The measured power from the microbattery is 16.2 nW with an open-circuit voltage of 899 mV and a short-circuit of 107.4 nA.

Wacharasindhu, T.; Kwon, J. W.; Meier, D. E.; Robertson, J. D.

2009-07-01

228

High efficiency radioisotope thermophotovoltaic prototype generator  

NASA Astrophysics Data System (ADS)

A radioisotope thermophotovoltaic generator space power system (RTPV) is lightweight, low-cost alternative to the present radioisotope thermoelectric generator system (RTG). The fabrication of such an RTPV generator has recently become feasible as the result of the invention of the GaSb infrared sensitive photovoltaic cell. Herein, we present the results of a parametric study of emitters and optical filters in conjuction with existing data on gallium antimonide cells. We compare a polished tungsten emitter with an Erbia selective emitter for use in combination with a simple dielectric filter and a gallium antimonide cell array. We find that the polished tungsten emitter is by itself a very selective emitter with low emissivity beyond 4 microns. Given a gallium antimonide cell and a tungsten emitter, a simple dielectric filter can be designed to transmit radiant energy below 1.7 microns and to reflect radiant energy between 1.7 and 4 microns back to the emitter. Because of the low long wavelength emissivity associated with the polished tungsten emitter, this simple dielectric filter then yields very respectable system performance. Also as a result of the longer wavelength fall-off in the tungsten emissivity curve, the radiation energy peak for a polished tungsten emitter operating at 1300 K shifts to shorter wavelengths relative to the blackbody spectrum so that the radiated energy peak falls right at the gallium antimonide cell bandedge. The result is that the response of the gallium antimonide cell is well matched to a polished tungsten emitter. We propose, therefore, to fabricate an operating prototype of a near term radioisotope thermophotovoltaic generator design consisting of a polished tungsten emitter, standard gallium antimonide cells, and a near-term dielectric filter. The Jet Propulsion Laboratory will design and build the thermal cavity, and JX Crystals will fabricate the gallium antimonide cells, dielectric filters, and resultant receiver panels. With 250 Watts of heat input, we expect this prototype to produce over 300 Watts of electrical energy output for a system energy conversion efficiency of over 12%. This low risk, near term design provides advances relative to present radioisotope thermophotovoltaic generators and has the additional advantage of allowing component and system development and testing to begin immediately. Improved cells and filters can easily be incorporated in this baseline system if they should become available in the future.

Avery, James E.; Samaras, John E.; Fraas, Lewis M.; Ewell, Richard

1995-10-01

229

Advanced radioisotope power sources for future deep space missions  

Microsoft Academic Search

The use of Radioisotope Thermoelectric Generators (RTGs) has been well established for deep space mission applications. The success of the Voyager, Galileo, Cassini and numerous other missions proved the efficacy of these technologies in deep space. Future deep space missions may also require Advanced Radioisotope Power System (ARPS) technologies to accomplish their goals. In the Exploration of the Solar System

Erik N. Nilsen

2001-01-01

230

RADIOISOTOPE TECHNOLOGY. Manual for AEC-NSF Institute  

Microsoft Academic Search

Principles of radioisotope technology are reviewed from the standpoint ; of radiation protection during scientific and industrial applications of ; radiation. Topics discussed include safety in work with radioisotopes, the ; design and use of radiation laboratories, nuclear radiation detection and ; measurement, methods of radiation dosimetry, counting equipment, gamma shielding, ; experimental techniques in tracer studies, and experiments in

Brownell

1961-01-01

231

Multi-mission radioisotope thermoelectric generator (MMRTG) program overview  

Microsoft Academic Search

Future NASA missions require safe, reliable, long-lived power systems for surface exploration of planetary bodies such as Mars as well as exploration of the solar system in the vacuum of space beyond Earth orbit. To address this need, the Department of Energy and NASA have initiated the development of radioisotope power systems, including the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). In

Fred Ritz; C. E. Peterson

2004-01-01

232

RADIOISOTOPE ELECTRIC PROPULSION FOR NEW FRONTIERS CLASS MISSIONS  

Microsoft Academic Search

With the initiation of the New Frontiers Class of space science missions, small radioisotope powered spacecraft for outer planet exploration will become reality. In order for these missions to co-orbit various primitive objects and moons of interest, a highly efficient electric propulsion system is needed. The use of such a radioisotope electric propulsion system is enabled by a new direct

Steven Oleson; Scott Benson; Michael Patterson; Jeffrey Schreiber; Douglas Fiehler

2003-01-01

233

Rhenium Radioisotopes for Therapeutic Radiopharmaceutical Development  

SciTech Connect

The availability of therapeutic radioisotopes at reasonable costs is important for applications in nuclear medicine, oncology and interventional cardiology, Rhenium-186 (Re-186) and rhenium-1 88 (Re-188) are two reactor-produced radioisotope which are attractive for a variety of therapeutic applications, Rhenium-186 has a half-life of 90 hours and decays with emission of a &particle with a maximum energy of 1.08 MeV and a 135 keV (9Yo) gamma which permits imaging. In contrast, Re- 188 has a much shorter half-life of 16.9 hours and emits a p-particle with a much higher energy of 2.12 MeV (Em=) and a 155 keV gamma photon (15Yo) for imaging. While Re-186 is unavailable from a generator system and must be directly produced in a nuclear reactor, Re-188 can also be directly produced in a reactor with high specific activity, but is more conveniently and cost-effectively available as carrier-free sodium perrhenate by saline elution of the alumina-based tungsten-188 (W1 88)/Re-l 88 generator system [1-2]. Since a comprehensive overviewofRe-186 and Re-188 therapeutic agents is beyond the scope of this &tended Abstrac4 the goal is to provide key examples of various agents currently in clinical use and those which are being developed for important clinical applications.

Beets, A.L.; Knapp, F.F., Jr.; Kropp, J.; Lin, W.-Y.; Pinkert, J.; Wang, S.-Y.

1999-01-18

234

Fuel-Rich Solid Propellant Boron Combustion.  

National Technical Information Service (NTIS)

Single particle boron ignition and combustion models developed in earlier phases of this program have been utilized and extended to treatment of boron cloud ignition, oxidizer depletion effects on cloud combustion time, laminar flame speeds in boron dust ...

J. Komar M. K. King R. S. Fry

1984-01-01

235

Boron: elementary challenge for experimenters and theoreticians.  

PubMed

Many of the fundamental questions regarding the solid-state chemistry of boron are still unsolved, more than 200 years after its discovery. Recently, theoretical work on the existence and stability of known and new modifications of the element combined with high-pressure and high-temperature experiments have revealed new aspects. A lot has also happened over the last few years in the field of reactions between boron and main group elements. Binary compounds such as B(6)O, MgB(2), LiB(1-x), Na(3)B(20), and CaB(6) have caused much excitement, but the electron-precise, colorless boride carbides Li(2)B(12)C(2), LiB(13)C(2), and MgB(12)C(2) as well as the graphite analogue BeB(2)C(2) also deserve special attention. Physical properties such as hardness, superconductivity, neutron scattering length, and thermoelectricity have also made boron-rich compounds attractive to materials research and for applications. The greatest challenges to boron chemistry, however, are still the synthesis of monophasic products in macroscopic quantities and in the form of single crystals, the unequivocal identification and determination of crystal structures, and a thorough understanding of their electronic situation. Linked polyhedra are the dominating structural elements of the boron-rich compounds of the main group elements. In many cases, their structures can be derived from those that have been assigned to modifications of the element. Again, even these require a critical revision and discussion. PMID:19830749

Albert, Barbara; Hillebrecht, Harald

2009-01-01

236

Boronated carbohydrate derivatives as potential boron neutron capture therapy reagents.  

PubMed

The treatment of cancer remains one of the most challenging problems for humanity. Boron neutron capture therapy is a binary approach for cancer treatment that is particularly attractive in treating high-grade gliomas and metastatic brain tumors. Among the types of boron-containing molecules used as boron neutron capture therapy agents, boronated carbohydrate derivatives have received significant attention because of their preferential uptake by growing tumor cells. This review provides a summary of the recent developments in the chemistry of carborane-containing carbohydrates. PMID:23617431

Marepally, Srinivasa R; Yao, Min-Liang; Kabalka, George W

2013-04-01

237

Assessment of radioisotope heaters for remote terrestrial applications  

SciTech Connect

This paper examines the feasibility of using radioisotope byproducts for special heating applications at remote sites in Alaska and other cold regions. The investigation included assessment of candidate radioisotope materials for heater applications, identification of the most promising cold region applications, evaluation of key technical issues and implementation constraints, and development of conceptual heater designs for candidate applications. Strontium-90 (Sr-90) was selected as the most viable fuel for radioisotopic heaters used in terrestrial applications. Opportunities for the application of radioisotopic heaters were determined through site visits to representative Alaska installations. Candidate heater applications included water storage tanks, sludge digesters, sewage lagoons, water piping systems, well-head pumping stations, emergency shelters, and fuel storage tank deicers. Radioisotopic heaters for water storage tank freeze-up protection and for enhancement of biological waste treatment processes at remote sites were selected as the most promising applications.

Uherka, K.L.

1987-05-01

238

Boron nitride nanotubes  

Microsoft Academic Search

The successful synthesis of pure boron nitride (BN) nanotubes is reported here. Multi-walled tubes with inner diameters on the order of 1 to 3 nanometers and with lengths up to 200 nanometers were produced in a carbon-free plasma discharge between a BN-packed tungsten rod and a cooled copper electrode. Electron energy-loss spectroscopy on individual tubes yielded B:N ratios of approximately

N. G. Chopra; R. J. Luyken; K. Cherrey; V. H. Crespi; M. L. Cohen; S. G. Louie; A. Zettl

1995-01-01

239

Boron deficiency in maize  

Microsoft Academic Search

Boron (B) deficiency depresses wheat, barley and triticale yield through male sterility. On the basis of field responses to\\u000a B fertilization, maize (Zea mays L.) is affected by B deficiency in five continents. In a series of sand culture trials with maize subject to B0 (nil added\\u000a B) and B20 (20 ?M added B) treatments, we described how B deficiency depressed

Sittichai Lordkaew; Bernard Dell; Sansanee Jamjod; Benjavan Rerkasem

2011-01-01

240

Method of fabricating boron containing coatings  

DOEpatents

Hard coatings are fabricated from boron nitride, cubic boron nitride, and multilayer boron/cubic boron nitride, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron is formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/cubic boron nitride, is produced by depositing alternate layers of boron and cubic boron nitride, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be discrete or of a blended or graded composition.

Makowiecki, Daniel M. (Livermore, CA); Jankowski, Alan F. (Livermore, CA)

1999-01-01

241

Radioisotope thermoelectric generator reliability and safety  

SciTech Connect

There are numerous occasions when a planetary mission requires energy in remote areas of the solar system. Anytime power is required much beyond Mars or the Asteroid Belts, solar power is not an option. The radioisotope thermoelectric generator (RTG) was developed for such a mission requirement. It is a relatively small and lightweight power source that can produce power under adverse conditions. Just this type of source has become the backbone of the power system for far outer plant exploration. Voyagers I and II are utilizing RTGs, which will soon power the Galileo spacecraft to Jupiter and the Ulysses spacecraft to study the solar poles. The paper discusses RTG operation including thermoelectric design, converter design, general-purpose heat source; RTG reliability including design, testing, experience, and launch approval; and RTG safety issues and methods of ensuring safety.

Campbell, R.; Klein, J.

1989-01-01

242

System and method for radioisotope identification  

US Patent & Trademark Office Database

A system and method are providing for analyzing radiation signature data (i.e., spectral data) produced by a detector device against stored data representing the computed interaction of known radioisotopic spectra with a representative cross section for each of a small number of material groups. Each material group comprises materials expected to be in a detection path of the detector and which exhibit similar cross sections. Comparative analysis is made of the spectral data received from the detector for threat materials to determine whether the spectral data indicates presence of a threat material in the interrogated space. The system and method is not limited to any particular detector type, and may be used with any detector that produces spectral data.

2013-06-11

243

Performance tuned radioisotope thermophotovoltaic space power system  

SciTech Connect

The trend in space exploration is to use many small, low-cost, special-purpose satellites instead of the large, high-cost, multipurpose satellites used in the past. As a result of this new trend, there is a need for lightweight, efficient, and compact radioisotope fueled electrical power generators. This paper presents an improved design for a radioisotope thermophotovoltaic (RTPV) space power system in the 10 W to 20 W class which promises up to 37.6 watts at 30.1{percent} efficiency and 25 W/kg specific power. The RTPV power system concept has been studied and compared to radioisotope thermoelectric generators (RTG) radioisotope, Stirling generators and alkali metal thermal electric conversion (AMTEC) generators (Schock, 1995). The studies indicate that RTPV has the potential to be the lightest weight, most efficient and most reliable of the three concepts. However, in spite of the efficiency and light weight, the size of the thermal radiator required to eliminate excess heat from the PV cells and the lack of actual system operational performance data are perceived as obstacles to RTPV acceptance for space applications. Between 1994 and 1997 EDTEK optimized the key converter components for an RTPV generator under Department of Energy (DOE) funding administered via subcontracts to Orbital Sciences Corporation (OSC) and EG&G Mound Applied Technologies Laboratory (Horne, 1995). The optimized components included a resonant micromesh infrared bandpass filter, low-bandgap GaSb PV cells and cell arrays. Parametric data from these components were supplied to OSC who developed and analyzed the performance of 100 W, 20 W, and 10 W RTPV generators. These designs are described in references (Schock 1994, 1995 and 1996). Since the performance of each class of supply was roughly equivalent and simply scaled with size, this paper will consider the OSC 20 W design as a baseline. The baseline 20-W RTPV design was developed by Schock, et al of OSC and has been presented elsewhere. The baseline design, centered around components and measured parametric data developed by EDTEK, Inc., promised an overall thermal-to-electric system output of 23 W at a conversion efficiency of 19{percent}, 1.92 kg system weight, and a specific power of 13.3 W/kg. The improved design reported herein promises up to 37.6 W at 30.1{percent} efficiency, 1.5 kg system weight, up to 25 W/kg specific power, a six-fold reduction in thermal radiator size over the baseline design, as well as a lower isotope temperature for greater safety. The six-fold reduction in thermal radiator size removes one of the greatest obstacles to applying RTPV in space missions. {copyright} {ital 1998 American Institute of Physics.}

Horne, W.E.; Morgan, M.D.; Saban, S.B. [EDTEK, Inc., 7082 South 220th Street, Kent, Washington 98032-1910 (United States)

1998-01-01

244

Pyrolytic deposition of carbon films containing nitorgen and\\/or boron  

Microsoft Academic Search

This paper reports carbon films containing nitrogen and\\/or boron prepared in a closed system by the pyrolysis of appropriate precursor materials. The decomposition products of the pyrolysis were identified and the resulting films were characterized by chemical and physical means. The electrical conductivity of the heteroatom-containing films is similar to that of pure amorphous carbon films. Boron nitride was present

Leon Maya; Lawrence A. Harris

1990-01-01

245

Influence of biofouling on boron removal by nanofiltration and reverse osmosis membranes  

Microsoft Academic Search

Excess of boron in water poses a problem due to adverse effects on crop production as well as human health and aquatic life. This study examined the influence of biofouling of NF and RO membrane on the performance of the membranes in removing boron from a synthetic wastewater effluent. Accelerated laboratory-scale biofouling experiments were carried out with commercial thin film

Esther Huertas; Moshe Herzberg; Gideon Oron; Menachem Elimelech

2008-01-01

246

Novel carboranylporphyrins for application in boron neutron capture therapy (BNCT) of tumors  

Microsoft Academic Search

Condensation of a new carboranylpyrrole 1 with benzaldehydes leads to ?-carboranylporphyrins 2 and 3 in good yields. These new porphyrins of high boron content (32–43%) have potential as boron delivery agents for BNCT. The X-ray structures of one ?-carboranylporphyrin, of a carboranylpyrrole, and of a side-product are presented.

J. Caleb Clark; Frank R. Fronczek; M. Graça H. Vicente

2005-01-01

247

Power burst facility\\/boron neutron capture therapy program for cancer treatment. [Borocaptate sodium  

Microsoft Academic Search

Highlights of the Power Burst Facility\\/Boron Neutron Capture Therapy (PBF\\/BNCT) Program in November, 1990 are described. One of our major projects is support of technological development. In this area, progress has been seen in gross boron analysis of biological samples, higher purity borocaptate sodium (BSH), planning of experiments to investigate BSH biochemistry and oxidation products, bidding out for an ion

Dorn

1990-01-01

248

Report on audit of funding for advanced radioisotope power systems  

SciTech Connect

The U.S. Department of Energy`s (Department) Advanced Radioisotope Power Systems Program maintains the sole national capability and facilities to produce radioisotope power systems for the National Aeronautics and Space Administration (NASA), the Department of Defense, and other Federal agencies. Projects are conducted with these agencies in accordance with written agreements and are dependent on cost sharing by the user agencies. For the past seven years the program emphasis has been on providing power systems for NASA`s Cassini mission to Saturn, which was launched earlier this month. We initiated this audit to determine whether the Department received proper reimbursement from NASA for the radioisotope power systems produced.

NONE

1997-10-17

249

Boron containing multilayer coatings and method of fabrication  

DOEpatents

Hard coatings are fabricated from multilayer boron/boron carbide, boron carbide/cubic boron nitride, and boron/boron nitride/boron carbide, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron and boron carbide used in forming the multilayers are formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/boron carbide, and boron carbide/cubic boron nitride is produced by depositing alternate layers of boron, cubic boron nitride or boron carbide, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be of a discrete or a blended or graded composition.

Makowiecki, Daniel M. (Livermore, CA); Jankowski, Alan F. (Livermore, CA)

1997-01-01

250

Combustion characteristics of boron nanoparticles  

Microsoft Academic Search

An experimental investigation of the combustion characteristics of boron nanoparticles in the post flame region of a flat flame burner has been conducted. Boron is attractive as a fuel or a fuel supplement in propellants and explosives due to its high heats of combustion on both a gravimetric and volumetric basis. A relatively large database exists for combustion characteristics of

Gregory Young; Kyle Sullivan; Michael R. Zachariah; Kenneth Yu

2009-01-01

251

Boron Clusters Come of Age  

ERIC Educational Resources Information Center

|Boron is the only element other than carbon that can build molecules of unlimited size by covalently boding to itself, a property known as catenation. In contrast to the chains and rings favored by carbon, boron arguably adopts a cluster motif that is reflected in the various forms of the pure element and in the huge area of polyhedral borane…

Grimes, Russell N.

2004-01-01

252

Nuclear energy in the service of biomedicine: the U.S. Atomic Energy Commission's radioisotope program, 1946-1950.  

PubMed

The widespread adoption of radioisotopes as tools in biomedical research and therapy became one of the major consequences of the "physicists' war" for postwar life science. Scientists in the Manhattan Project, as part of their efforts to advocate for civilian uses of atomic energy after the war, proposed using infrastructure from the wartime bomb project to develop a government-run radioisotope distribution program. After the Atomic Energy Bill was passed and before the Atomic Energy Commission (AEC) was formally established, the Manhattan Project began shipping isotopes from Oak Ridge. Scientists and physicians put these reactor-produced isotopes to many of the same uses that had been pioneered with cyclotron-generated radioisotopes in the 1930s and early 1940s. The majority of early AEC shipments were radioiodine and radiophosphorus, employed to evaluate thyroid function, diagnose medical disorders, and irradiate tumors. Both researchers and politicians lauded radioisotopes publicly for their potential in curing diseases, particularly cancer. However, isotopes proved less successful than anticipated in treating cancer and more successful in medical diagnostics. On the research side, reactor-generated radioisotopes equipped biologists with new tools to trace molecular transformations from metabolic pathways to ecosystems. The U.S. government's production and promotion of isotopes stimulated their consumption by scientists and physicians (both domestic and abroad), such that in the postwar period isotopes became routine elements of laboratory and clinical use. In the early postwar years, radioisotopes signified the government's commitment to harness the atom for peace, particularly through contributions to biology, medicine, and agriculture. PMID:17575955

Creager, Angela N H

2006-01-01

253

Boron nitride nanotubes  

SciTech Connect

The successful synthesis of pure boron nitride (BN) nanotubes is reported here. Multi-walled tubes with inner diameters on the order of 1 to 3 nanometers and with lengths up to 200 nanometers were produced in a carbon-free plasma discharge between a BN-packed tungsten rod and a cooled copper electrode. Electron energy-loss spectroscopy on individual tubes yielded B:N ratios of approximately 1, which is consistent with theoretical predictions of stable BN tube structures. 15 refs., 4 figs.

Chopra, N.G.; Luyken, R.J.; Cherrey, K. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)] [and others

1995-08-18

254

Advanced Radioisotope Power Conversion Technology Research and Development.  

National Technical Information Service (NTIS)

NASA's Radioisotope Power Conversion Technology program is developing next generation power conversion technologies that will enable future missions that have requirements that cannot be met by either the ubiquitous photovoltaic systems or by current Radi...

W. A. Wong

2004-01-01

255

Radioisotope Imaging of Brain Tumors in Two Rhesus Monkeys.  

National Technical Information Service (NTIS)

Two geriatic male rhesus monkeys were used for the radioisotope imaging in this research. Discussion of the radionuclide, materials and method used to accomplish the neurologic examination and the results obtained, both during the procedure and confirmati...

D. Romo D. H. Wood J. W. Fanton R. E. Cordts R. K. Harris

1988-01-01

256

Reentry Thermal Testing of Light-Weight Radioisotope Heater Units.  

National Technical Information Service (NTIS)

Two Light-Weight Radioisotope Heater Units (LWRHU) were exposed to thermal ramps simulating atmospheric reentry. The helium release rates were measured during each test and modeled after simple diffusion theory. The reentry pulses did not result in swelli...

D. E. Peterson J. S. Starzynski

1982-01-01

257

Environmental assessment for radioisotope heat source fuel processing and fabrication.  

National Technical Information Service (NTIS)

DOE has prepared an Environmental Assessment (EA) for radioisotope heat source fuel processing and fabrication involving existing facilities at the Savannah River Site (SRS) near Aiken, South Carolina and the Los Alamos National Laboratory (LANL) near Los...

1991-01-01

258

Physical Characteristics of Principal Radioisotopes Used in Biological Sciences.  

National Technical Information Service (NTIS)

A table, with physical characteristics of radioisotopes used in biological sciences is presented. It includes data of half-life, decay, electron capture, isomeric transitron, etc. (Atomindex citation 09:414050)

V. F. Nascimento Filho

1977-01-01

259

Interplanetary Sample Return Missions Using Radioisotope Electric Propulsion.  

National Technical Information Service (NTIS)

Solar electric propulsion (SEP) is being used for a variety of planetary missions sponsored by ESA, JAXA, and NASA and nuclear electric propulsion (NEP) is being considered for future, flagship-class interplanetary missions. Radioisotope electric propulsi...

R. Williams Y. Gao C. A. Kluever M. Cupples J. Belcher

2005-01-01

260

Determining Molar Combining Ratios Using Radioisotopes--A Student Experiment  

ERIC Educational Resources Information Center

|Outlines an experimental procedure in which an iodine radioisotope is used to determine molar combining ratios of lead and silver with the iodine. Tables and graphs show the definitive results that should be attainable. (CP)|

Sears, Jerry A.

1976-01-01

261

Work in progress: radioisotopic evaluaton of gastroplasty patients  

SciTech Connect

Radioisotopic gastric emptying studies, using technetium-99m-sulfur-colloid-labeled egg, were performed in 14 patients who had undergone gastroplasty. The radioisotopic method was found to be a good quantitative indicator of the amount of solids that empty from the stomach and a useful tool in the long-term follow-up of gastroplasty patients. It was particularly helpful in evaluating the efficacy of surgery in patients with poor postsurgical weight reduction.

Drane, W.E.; Marks, D.S.; Simms, S.M.; Saylor, J.G.; Haas, P.A.; Kambouris, A.H.

1983-04-01

262

Work in progress: radioisotopic evaluation of gastroplasty patients  

SciTech Connect

Radioisotopic gastric emptying studies, using technetium-99m-sulfur-colloid-labeled egg, were performed in 14 patients who had undergone gastroplasty. The radioisotopic method was found to be a good quantitative indicator of the amount of solids that empty from the stomach and a useful tool in the longterm follow-up of gastroplasty patients. It was particularly helpful in evaluating the efficacy of surgery in patients with poor postsurgical weight reduction.

Drane, W.E.; Marks, D.S.; Simms, S.M.; Saylor, J.G.; Haas, P.A.; Kambouris, A.A.

1983-04-01

263

Boron adsorption mechanism on polyvinyl alcohol  

Microsoft Academic Search

Recently, an increase in the use of boron compounds has led to an increase in boron emissions, and concern has grown regarding\\u000a its detrimental effects on the human body. An adsorbent that adsorbs boron selectively has been developed as a countermeasure.\\u000a Although certain commercially available boron selective adsorbents can be used to remove boron from aqueous solutions by utilizing\\u000a the

Atsuhiro Harada; Toshiyuki Takagi; Sho Kataoka; Takuji Yamamoto; Akira Endo

2011-01-01

264

METHOD OF COATING SURFACES WITH BORON  

DOEpatents

A method of forming a thin coating of boron on metallic, glass, or other surfaces is described. The method comprises heating the article to be coated to a temperature of about 550 d C in an evacuated chamber and passing trimethyl boron, triethyl boron, or tripropyl boron in the vapor phase and under reduced pressure into contact with the heated surface causing boron to be deposited in a thin film.

Martin, G.R.

1949-10-11

265

Synthesis of ? - and ? Rhombohedral Boron Powders via Gas Phase Thermal Dissociation of Boron Trichloride by Hydrogen  

Microsoft Academic Search

The ?-rhombohedral and ?-rhombohedral crystal structures of pure elemental boron powders have been synthesized via gas phase thermal dissociation\\u000a of BCl3 by H2 on a quartz substrate. The parameters affecting the crystal structures of the final products and the process efficiency,\\u000a such as BCl3\\/H2 molar ratio (1\\/2 and 1\\/4) and reaction temperature (1173 K to 1373 K [900 °C to 1100 °C]), have been examined.

Duygu A?ao?ullar?; Özge Balc?; ?sma?l Duman; M. Lütf? Öveço?lu

2011-01-01

266

Sulfonate pseudohalides of boron subphthalocyanine.  

PubMed

The crystal structures of three sulfonate pseudohalide derivatives of boron subphthalocyanine (BsubPc) are described and compared with four structures of three published sulfonate derivatives. Benzenesulfonate boron subphthalocyanine [(benzenesulfonato)(subphthalocyaninato)boron, C(30)H(17)BN(6)O(3)S, (I)] crystallizes in the space group P-1 with Z = 2. The structure contains two centrosymmetric ?-stacking interactions between the concave faces of the isoindoline units in the BsubPc ligands. 3-Nitrobenzenesulfonate boron subphthalocyanine [(3-nitrobenzenesulfonato)(subphthalocyaninato)boron, C(30)H(16)BN(7)O(5)S, (II)] crystallizes in the space group P2(1)/c with Z = 4. The structure contains an intermolecular S-O···? interaction from the sulfonate group to a five-membered N-containing ring of an isoindoline unit on the concave side of a neighbouring BsubPc ligand, at a distance of 3.151 (3) Å. The crystal of methanesulfonate boron subphthalocyanine [(methanesulfonato)(subphthalocyaninato)boron, C(25)H(15)BN(6)O(3)S, (III)] was produced via sublimation and it is not a solvate, in contrast with two previously published structures of the same compound. Compound (III) crystallizes in the space group P2(1)/n with Z = 2, and its structure is similar to that of the more common compound Cl-BsubPc. PMID:23124463

Paton, Andrew S; Lough, Alan J; Bender, Timothy P

2012-10-19

267

Raman spectroscopy of boron carbides and related boron-containing materials  

Microsoft Academic Search

Raman spectra of crystalline boron, boron carbide, boron arsenide (B12As2), and boron phosphide (B12P2) are reported. The spectra are compared with other boron-containing materials containing the boron icosahedron as a structural unit. The spectra exhibit similar features some of which correlate with the structure of the icosahedral units of the crystals. The highest Raman lines appear to be especially sensitive

J. A. Shelnutt; B. Morosin; D. Emin; A. Mullendore; G. Slack; C. Wood

1986-01-01

268

Raman spectroscopy of boron carbides and related boron-containing materials  

Microsoft Academic Search

Raman spectra of crystalline boron, boron carbide, boron arsenide (B12As2), and boron phosphide (B12P2) are reported. The spectra are compared with other boron-containing materials containing the boron icosahedron as a structural unit. The spectra exhibit similar features some of which correlate with the structure of the icosahedral units of the crystals. The highest Raman lines appear to be especially sensitive

J. A. Shelnutt; B. Morosin; D. Emin; A. Mullendore; G. Slack; C. Wood

1985-01-01

269

Formation of boron fluoro-chloride in the separation of boron isotopes by multiphoton absorption of BCl/sub 3/  

SciTech Connect

The reaction products in the process of boron isotope separation by multiphoton absorption of BCl/sub 3/ have been studied. When oxygen was used as the scavenger, the stable solid product was B/sub 2/O/sub 3/, while (BOCl)/sub 3/ was not found. Our experiments have shown that when irradiated by a focused TEA CO/sub 2/ laser beam, BCl/sub 3/ reacted with fluorocarbon grease to form boron fluoro-chloride and boron trifluoride. A possible mechanism for the reaction between BCl/sub 3/ and fluorocarbon grease has been proposed. It seems that BCl/sub 3/ was first dissociated into BCl/sub 2/ and Cl under the intense IR laser action, and BCl/sub 2/ then reacted with fluorocarbon grease to form BFCl/sub 2/. Besides, BF/sub 2/Cl and BF/sub 3/ were formed from BFCl/sub 2/.

Li, L.; Chen, G.; Zhang, R.; Kang, N.

1982-04-01

270

[Diagnosis of venous thrombosis by using radioisotopes].  

PubMed

Thromboembolism problem is a grave complication which occurs with great frequency in patients hospitalized in a critical state. The association between periferical venous thrombosis and the thromboembolic accident is plainly demonstrated, although the accurate establishment of the clinical diagnosis of phlebothrombosis is only feasible in 50% of the cases. In the present work, we describe the methodology and the experience which we have acquired with the use of radioisotops in the diagnosis of these problems. We studied 64 patients to whom in the supine position we injected into a vein in both heels, from 3 to 5 millicuries of 99m-Tecnecio, practicing three stages: dynamic venography, a static study, and a pulmonary gammagram. In the normal cases, we clearly identified the tracts of the principal femural, iliac, and the inferior third of the inferior vena cava veins. In the abnormal studies, we observed the obstructive process manifested by the absence of radioactivity in the affected venous tract, with appearence of collateral circulation, definitive data which establishes with certainty the diagnosis. It can be concluded that the method is rapid and easily carried out, meaning that it could be a routine practice in all of those patients who are suspected of having this problem. PMID:1015903

Gordon, F; Ramírez, F; Muñoz, R; Alcántara, R; Flores Izquierdo, G

271

Light-weight radioisotope heater impact tests  

SciTech Connect

The light-weight radioisotope heater unit (LWRHU) is a {sup 238}PuO{sub 2}-fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed {sup 238}PuO{sub 2} fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabricated for the Cassini mission with the performance of those fabricated for the Galileo mission, and to determine a failure threshold, two types of impact tests were conducted. A post-reentry impact test was performed on one of 180 flight-quality units produced for the Cassini mission and a series of sequential impact tests using simulant-fueled LWRHU capsules were conducted respectively. The results showed that deformation and fuel containment of the impacted Cassini LWRHU was similar to that of a previously tested Galileo LWRHU. Both units sustained minimal deformation of the aeroshell and fueled capsule; the fuel was entirely contained by the platinum capsule. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s.

Reimus, M.A.H.; Rinehart, G.H.; Herrera, A. [and others

1998-12-31

272

Radioisotopic heater units warm an interplanetary spacecraft  

SciTech Connect

The Cassini orbiter and Huygens probe, which were successfully launched on October 15, 1997, constitute NASA`s last grand-scale interplanetary mission of this century. The mission, which consists of a four-year, close-up study of Saturn and its moons, begins in July 2004 with Cassini`s 60 orbits of Saturn and about 33 fly-bys of the large moon Titan. The Huygens probe will descend and land on Titan. Investigations will include Saturn`s atmosphere, its rings and its magnetosphere. The atmosphere and surface of Titan and other icy moons also will be characterized. Because of the great distance of Saturn from the sun, some of the instruments and equipment on both the orbiter and the probe require external heaters to maintain their temperature within normal operating ranges. These requirements are met by Light Weight Radioisotope Heater Units (LWRHUs) designed, fabricated and safety tested at Los Alamos National Laboratory, New Mexico. An improved gas tungsten arc welding procedure lowered costs and decreased processing time for heat units for the Cassini spacecraft.

Franco-Ferreira, E.A. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.; Rinehart, G.H. [Los Alamos National Lab., NM (United States)

1998-01-01

273

Radioisotope Power Sources for MEMS Devices,  

SciTech Connect

Microelectromechanical systems (MEMS) comprise a rapidly expanding research field with potential applications varying from sensors in airbags to more recent optical applications. Depending on the application, these devices often require an on-board power source for remote operation, especially in cases requiring operation for an extended period of time. Previously suggested power sources include fossil fuels and solar energy, but nuclear power sources may provide significant advantages for certain applications. Hence, the objective of this study is to establish the viability of using radioisotopes to power realistic MEMS devices. A junction-type battery was constructed using silicon and a {sup 63}Ni liquid source. A source volume containing 64 {micro}Ci provided a power of {approx}0.07 nW. A more novel application of nuclear sources for MEMS applications involves the creation of a resonator that is driven by charge collection in a cantilever beam. Preliminary results have established the feasibility of this concept, and future work will optimize the design for various applications.

Blanchard, J.P.

2001-06-17

274

Boron nanowires for flexible electronics  

NASA Astrophysics Data System (ADS)

Flexible boron nanowires have been synthesized via thermoreduction in boron-oxygen compounds with magnesium. These as-prepared nanowires, which are structurally uniform and single crystalline, represent good semiconductor at high temperature. Tensile stress measurements demonstrate excellent mechanical property of boron nanowires as well as resistance to mechanical fracture even under a strain of 3%. Importantly, simultaneous electrical measurement reveals that the corresponding electrical conductance is very robust and remains constant under mechanical strain. Our results can be briefly explained by Mott's variable range hopping model.

Tian, Jifa; Cai, Jinming; Hui, Chao; Zhang, Chendong; Bao, Lihong; Gao, Min; Shen, Chengmin; Gao, Hongjun

2008-09-01

275

Boron-oxygen luminescence centres in boron-nitrogen systems.  

PubMed

Closed-shell BO(2)(-) and BO(-) anions are proposed as high-efficiency luminescence centres in boron-nitrogen systems, which makes the anions localized and leads to a radiation transition. PMID:17989804

Tang, Chengchun; Bando, Yoshio; Zhi, Chunyi; Golberg, Dmitri

2007-09-04

276

Measurement of the K shell X-ray production cross-sections and fluorescence yields for Nd, Eu, Gd, Dy and Ho using radioisotope X-ray fluorescence in the external magnetic field  

NASA Astrophysics Data System (ADS)

The effect of external magnetic field on the K? and K? X-ray production cross-sections and K shell fluorescence yields for ferromagnetic elements Nd, Gd and Dy and paramagnetic elements Eu and Ho have been measured at the excitation energy of 59.5 keV ? -rays from 241Am radioactive source of strength 100 mCi in the external magnetic field of intensities ±0.75 T. Furthermore, IK? /IK? intensity ratios for these elements have been measured in the external magnetic field. The K X-rays from different targets were detected using a high resolution Si(Li) semiconductor detector. For B = 0, the measured K X-ray production cross-sections, K shell fluorescence yields and the IK? /IK? intensity ratios were compared with the experimental and theoretical data in literature. The results have shown that the fluorescence parameters as photoionization cross section, fluorescence yield, radiation rates and spectral linewidth can change when the irradiation is conducted in a magnetic field.

Demir, D.; ?ahin, Y.

2007-05-01

277

Carbothermal formation and microstrutural evolution of ??-Sialon–AlN–BN powders from boron-rich blast furnace slag  

Microsoft Academic Search

Boron-rich blast furnace slag of low activity is one of the major products created during the separation of iron and boron from ludwigite in a blast furnace process, and the high-efficiency utilisation of its is of great importance to the Chinese boron industry. This paper proposes one new application process to synthesize ??-Sialon–AlN–BN powders by a carbothermal reduction–nitridation method using

Tao Jiang; Junbin Wu; Xiangxin Xue; Peining Duan; Mansheng Chu

278

BORON SYNTHESIS IN TYPE Ic SUPERNOVAE  

SciTech Connect

We investigate the {nu}-process in an energetic Type Ic supernova (SN Ic) and the resultant productions of the light elements including boron and its stable isotopes. SN Ic is a very unique boron source because it can produce boron not only through spallation reactions as discussed in Nakamura and Shigeyama but also the {nu}-process. The {nu}-process is considered to occur in core-collapse supernovae and previous studies were limited to SNe II. Although the progenitor star of an SN Ic does not posses an He envelope so that {sup 7}Li production via the {nu}-process is unlikely, {sup 11}B can be produced in the C-rich layers. We demonstrate a hydrodynamic simulation of a SN Ic explosion and estimate the amounts of the light elements produced via the {nu}-process for the first time, and also the subsequent spallation reactions between the outermost layers of the compact SN Ic progenitor and the ambient medium. We find that the {nu}-process in the current SN Ic model produces a significant amount of {sup 11}B, which is diluted by {sup 10}B from spallation reactions to get closer to B isotopic ratios observed in meteorites. We also confirm that high-temperature {mu} and {tau} neutrinos and their anti-neutrinos, reasonably suggested from the compact structure of SN Ic progenitors, enhance the light-element production through the neutral current reactions, which may imply an important role of SNe Ic in the Galactic chemical evolution.

Nakamura, Ko; Kajino, Toshitaka [National Astronomical Observatory of Japan, Mitaka, Tokyo (Japan); Yoshida, Takashi; Shigeyama, Toshikazu [Department of Astronomy, Graduate School of Science, University of Tokyo, Tokyo (Japan)

2010-08-01

279

Crystallization of comminuted boron powders  

Microsoft Academic Search

An x-ray diffraction investigation has established that, irrespective of their degree of amorphization, comminuted boron powders crystallize after melting in the rhombohedralß structure, i.e., revert to their original crystalline state.

K. P. Tsomaya; D. L. Gabuniya; É. A. Knyshev; V. A. Kobyakov

1975-01-01

280

Snub boron nanostructures: Chiral fullerenes, nanotubes and planar sheet  

Microsoft Academic Search

We design a new class of electronically stable boron nanostructures, viz.: 60n2 boron fullerene family, boron nanotubes, and a planar boron sheet, which like the ?-boron sheet, consists of triangular and hexagonal motifs and has symmetrically arranged hexagonal holes. The binding energy of the proposed new boron sheet is only 0.02eV\\/atom lower than the ?-boron sheet. The 60n2 boron fullerenes

Rajendra R. Zope; Tunna Baruah

2011-01-01

281

Boron doped nanostructured diamond films  

Microsoft Academic Search

A chemical vapor deposition hydrogen\\/methane\\/nitrogen feed-gas mixture with unconventionally high methane (15% CH4 by volume) normally used to grow ultra-hard and smooth nanostructured diamond films on Ti-6Al-4V alloy substrates was modified to include diborane B2H6 for boron-doping of diamond films. The flow rates for B2H 6 and N2 were varied to investigate their effect on plasma chemistry, film structure, boron

Qi Liang

2004-01-01

282

Boronic esters in asymmetric synthesis.  

PubMed

The author's work on (?-haloalkyl)boronic esters as reagents for asymmetric synthesis is reviewed. Diastereomeric ratios exceeding 1000 can be achieved with this chemistry, and ratios around 100 are commonplace. The method allows sequential installation of a series of stereocenters and tolerates a wide variety of suitably protected functional substituents. (?-Amidoalkyl)boronic acids include biochemically significant serine protease inhibitors, one of which is the clinically successful proteasome inhibitor bortezomib, used for treatment of multiple myeloma and mantle cell lymphoma. PMID:23875690

Matteson, Donald S

2013-08-14

283

Magnetron sputtered boron films for increasing hardness of a metal surface  

DOEpatents

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence.

Makowiecki, Daniel M. (Livermore, CA); Jankowski, Alan F. (Livermore, CA)

2003-05-27

284

Initial boronization of PBX-M using ablation from solid boronized probes  

SciTech Connect

Boronization was performed by plasma ablation of two solid boronized target probes. Probe-1, in a mushroom shape, consisted of a 10.7% boronized two-dimensional carbon-carbon composite containing 3.6 g of boron in a B[sub 4]C binder. Probe-2, in a rectangular shape, consisted of an 86% boronized graphite felt composite containing 19.5 g of 40-[mu]m boron particles. Probe-1 boronization deposited [approximately]26 monolayers of boron. After boronization with Probe-1, the loop voltage in 1-MW neutral-beam-heated plasmas decreased 27%, and volt-second consumption decreased 20%. Strong peripheral spectral lines from low-Z elements decreased by factors of [approximately]5. The central oxygen density decreased 15 to 20%. Carbon levels initially increased during boronization but were significantly reduced after boronization. The total radiated power during neutral beam injection decreased by 43%. Probe-2 boronization deposited [approximately]70 monolayers. Probe-2 boronization exhibited similar improved plasma conditions, but for some parameters, a smaller percentage change occurred because of the previous boronization with Probe-1. The ablation rates of both probes were consistent with front-face temperatures above the boron melting point. The results demonstrate the performance of two different boronized probe materials and the relative simplicity and effectiveness of solid target boronization as a convenient, real-time impurity control technique. 20 refs., 10 figs., 1 tab.

Kugel, H.W.; Timberlake, J.; Bell, R.; Kaita, R.; Kaye, S.; Okabayashi, M.; Paul, S.; Takahashi, H.; Tighe, W.; Von Goeler, S. (Princeton Univ., NJ (United States)) (and others)

1994-07-01

285

Light-Weight Radioisotope Heater Unit  

SciTech Connect

DOE is developing a new generation of radioisotope-fueled 1-watt heaters, for initial use on NASA's upcoming Galileo and International Solar-Polar Missions. Each heater must contain passive safety provisions to ensure fuel retention under all credible accident conditions. Initial design reviews raised some concern about the accuracy of the predicted peak reenetry temperature, and about the adequacy of the safety margin under certain unlikely - but not impossible-reentry modes. Of particular concern was the possile release of the accumulated helium inventory from the fuel during the reentry heat pulse, and the potential effect of enhanced heat conduction due to helium buildup in gaps. The latter problem had not been addressed in previous studies. Fairchild carried out a large number of reentry thermal analyses to resolve the analytical uncertainties, and proposed design changes to reduce the thermal coupling between the aeroshell and the fuel capsule. For the computed reentry temperature history of the modified design, the rate of helium buildup in the gaps was analyzed. The analysis accounted for temperature-dependent helium diffusion through the fuel pellet and for leakage to space through the permeable aeroshell. It showed that most of the helium inventory leaves the fuel during reentry, but that it never reaches a continuum pressure in the gaps, and therefore has no significant thermal effect. Under these conditions, the Fairchild-modified design provides ample safety margin against clad failure, even for very unlikely reenty trajectories. The modified design was successfully vibration-tested and was subsequently adopted by the project. Cross Reference CID #8517. There are two copies in the file.

Schock, Alfred

1981-04-01

286

Azomethine H colorimetric method for determining dissolved boron in water  

USGS Publications Warehouse

An automated colorimetric method for determining dissolved boron in water is described. The boron is complexed with azomethine H, which is readily available as the condensation product of H acid (8-amino-1-naphthol-3,6-disulfonic acid) and salicylaldehyde. The absorbance of the yellow complex formed is then measured colorimetrically at 410 nm. Interference effects from other dissolved species are minimized by the addition of diethylenetriaminepentaacetic acid (DTPA); however, iron, zinc, and bicarbonate interfere at concentrations above 400 ??g/L, 2000 ??g/L, and 200 mg/L, respectively. The bicarbonate interference can be eliminated by careful acidification of the sample with concentrated HCl to a pH between 5 and 6. Thirty samples per hour can be routinely analyzed over the range of from 10 to 400 ??g/L, boron.

Spencer, R. R.; Erdmann, D. E.

1979-01-01

287

ClusterBoron Implant Alternative to BF{sub 2} PMOS SDE  

SciTech Connect

As device geometries scale, the formation of the SDE becomes increasingly difficult and increasingly important. For advanced technologies, new methods such as ultra-low-energy boron implantation and millisecond annealing (flash or laser) are necessary to achieve the required junction characteristics. In addition, these processes must be compatible with the remainder of the process flow, which might include advanced dielectrics, stress technologies, SOI, etc. The emergence of ClusterBoron as a high productivity alternative for the low energy implant creates interest in device performance possible in a realistic process flow. This paper will present an evaluation of the use of ClusterBoron for the PMOS SDE in an advanced 65 nm logic process which includes laser annealing, e-SiGe stress layers and SOI. The conventional process uses a BF2 SDE process. Complete device characteristics will be shown comparing the ClusterBoron SDE to the conventional BF2. It will be shown that the ClusterBoron process achieves better boron activation, leading to enhanced transistor drive current. It will also be shown that the ClusterBoron is compatible with the SiGe stress layers and SOI structure. In summary, ClusterBoron presents an attractive alternative to the conventional BF2 process for advanced PMOS SDE.

Feudel, Thomas; Illgen, Ralf; Krueger, Christian; Braun, Marek [AMD Saxony, LLC and Co. KG, Wilschdorfer Landstr 101, D01109 Dresden (Germany); Sekar, Karuppanan; Lee, David; Krull, Wade [SemEquip, Inc., 34 Sullivan Road, North Billerica, Massachusetts 01862 (United States)

2008-11-03

288

Synthesis, Salvage, and Catabolism of Uridine Nucleotides in Boron-Deficient Squash Roots 1  

PubMed Central

Previous work has provided evidence that plants may require boron to maintain adequate levels of pyrimidine nucleotides, suggesting that the state of boron deficiency may actually be one of pyrimidine starvation. Since the availability of pyrimidine nucleotides is influenced by their rates of synthesis, salvage, and catabolism, we compared these activities in the terminal 3 centimeters of roots excised from boron-deficient and -sufficient squash plants (Cucurbita pepo L.). Transferring 5-day-old squash plants to a boron-deficient nutrient solution resulted in cessation of root elongation within 18 hours. However, withholding boron for up to 30 hours did not result in either impaired de novo pyrimidine biosynthesis or a change in the sensitivity of the de novo pathway to regulation by end product inhibition. Boron deprivation had no significant effect on pyrimidine salvage or catabolism. These results provide evidence that boron-deficient plants are not starved for uridine nucleotides collectively. Whether a particular pyrimidine nucleotide or derivative is limiting during boron deprivation remains to be examined.

Lovatt, Carol J.; Albert, Luke S.; Tremblay, George C.

1981-01-01

289

Mild Rh(III)-catalyzed C-H activation and annulation with alkyne MIDA boronates: short, efficient synthesis of heterocyclic boronic acid derivatives.  

PubMed

Taking advantage of Rh(III)-catalyzed C-H activation reactions, we have developed a mild, short, and efficient method for the synthesis of bench-stable 3-isoquinolone MIDA boronates. The reaction is practical and scalable. The product formed has been applied in the Suzuki-Miyaura reaction with high efficiency. This strategy has also been successfully expanded to the synthesis of MIDA boronate functionalized heterocycles such as isoquinoline, pyrrole, and indole. PMID:23146122

Wang, Honggen; Grohmann, Christoph; Nimphius, Corinna; Glorius, Frank

2012-11-20

290

A new boron impregnation technique of wood by vapor boron of boric acid to reduce leaching boron from wood  

Microsoft Academic Search

This study was designed to reveal impregnation ability and to enhance leaching resistance of boron from borate-treated wood. Vapor boron treatment was applied in compressed and uncompressed states at high temperatures such as 180 and 200°C for 6, 8 and 15 min. Following ten-cycle leaching periods, amounts of boron leached from vapor boron treated wood was measured by ion chromatography. According

Ergun Baysal; Mustafa Kemal Yalinkilic

2005-01-01

291

Boron doped nanostructured diamond films  

NASA Astrophysics Data System (ADS)

A chemical vapor deposition hydrogen/methane/nitrogen feed-gas mixture with unconventionally high methane (15% CH4 by volume) normally used to grow ultra-hard and smooth nanostructured diamond films on Ti-6Al-4V alloy substrates was modified to include diborane B2H6 for boron-doping of diamond films. The flow rates for B2H 6 and N2 were varied to investigate their effect on plasma chemistry, film structure, boron incorporation, and mechanical properties. It was found that boron atoms can easily be incorporated into diamond films and change the lattice constant and film structure. Nitrogen, on the other hand, competes with boron in the plasma and acts to prevent boron incorporation into the diamond structure. In addition, with the appropriate choice of deposition conditions, the film structure can be tailored to range from highly crystalline, well faceted diamond to nanocrystalline diamond. Glancing angle X-ray diffraction and Micro-Raman were used as the main tools to investigate the relation between processing and structure. An optimal N2/CH4 ratio of 0.4 was found to result in a film with a minimum in grain size and surface roughness, along with high boron incorporation (˜4 x 1020 cm-3). Mechanical properties and thermal stability of boron doped nanostructured diamond films were examined by means of nanoindentation, open air thermal annealing, and nanotribometry. It was found that the films have high hardness close to that of undoped nanostructured diamond films. Thermal stability of these films was evaluated by heating in an oxygen environment above 700°C. Improved thermal stability of boron doped nanostructured diamond films was observed. Tribological tests show that although both undoped and boron doped nanostructured diamond films show extremely low coefficient of friction and wear rate as compared with uncoated titanium alloys (Ti-6Al-4V) and cobalt chrome alloy (Co-Cr-Mo), a critical failure max stress of 2.2 GPa was observed for boron doped nanostructured diamond films. A FORTRAN Chemical Kinetics Package for the Analysis of Gas Phase Chemical Kinetics, gas-phase thermodynamic equilibrium calculations involving H 2/CH4/N2/B2H6 mixtures was employed to investigate the chemical interactions leading to boron incorporation and crystalline structure variations. The strong influence of the BH 3 in causing the boron incorporation and the role of CN radical in causing the nanocrystallinity are confirmed by the correlation of their modeled compositions in the gas phase with boron content and degree of nanocrystallinity as determined experimentally. A good degree of agreement was obtained between the theoretically predicted gas phase concentration of species and the experimental concentration trends as measured by the optical emission spectroscopy of the microwave plasma. Overall, high film hardness and toughness, combined with good thermal stability and low surface roughness, indicate that nanostructured boron doped diamond films can be used as wear resistant coatings that are able to withstand high temperature oxidizing environments.

Liang, Qi

292

Impact of carbon coimplantation on boron behavior in silicon: Carbon-boron coclustering and suppression of boron diffusion  

Microsoft Academic Search

Coimplantation of heterogeneous dopants in materials can be used to control the principal dopant distribution. We used atom probe tomography (APT) and secondary ion mass spectrometry (SIMS) to investigate the impact of coimplanted carbon on boron diffusion in silicon. After annealing, three-dimensional APT analysis of dopant distributions revealed the presence of carbon-boron coclusters around the projection range of boron. In

Y. Shimizu; H. Takamizawa; K. Inoue; T. Toyama; Y. Nagai; N. Okada; M. Kato; H. Uchida; F. Yano; T. Tsunomura; A. Nishida; T. Mogami

2011-01-01

293

Boron Nitride Nanotubes-Reinforced Glass Composites.  

National Technical Information Service (NTIS)

Boron nitride nanotubes of significant lengths were synthesized by reaction of boron with nitrogen. Barium calcium aluminosilicate glass composites reinforced with approximately 4 weight percent of BN nanotubes were fabricated by hot pressing. Ambient-tem...

N. Bansal J. B. Hurst S. R. Choi

2005-01-01

294

Corrosion inhibitors for boron-containing lubricants  

Microsoft Academic Search

Lubricating compositions containing an oxidation inhibitor, copper and lead corrosion inhibitors and boron and\\/or metal-boron derivatives having extreme pressure, anti-wear and friction reducing properties are disclosed.

R. A. Holstedt; P. Jessup

1983-01-01

295

A Method for Estimating Blood Meal Volume in Aedes Aegypti using a Radioisotope.  

National Technical Information Service (NTIS)

A study was conducted to determine the feasibility of measuring blood meal volume in Aedes aegypti using a radioisotope blood label in lieu of weight differentials. When mosquitoes were fed on blood labeled with Ce-144, this radioisotope remained complete...

B. C. Redington W. T. Hockmeyer

1976-01-01

296

Synthesis of ?- and ?-Rhombohedral Boron Powders via Gas Phase Thermal Dissociation of Boron Trichloride by Hydrogen  

NASA Astrophysics Data System (ADS)

The ?-rhombohedral and ?-rhombohedral crystal structures of pure elemental boron powders have been synthesized via gas phase thermal dissociation of BCl3 by H2 on a quartz substrate. The parameters affecting the crystal structures of the final products and the process efficiency, such as BCl3/H2 molar ratio (1/2 and 1/4) and reaction temperature (1173 K to 1373 K [900 °C to 1100 °C]), have been examined. The experimental apparatus of original design has enabled boron powders to be obtained at temperatures lower than those in the literature. The surface/powder separation problem encountered previously with different substrate materials has been avoided. Boron powders have been synthesized with a minimum purity of 99.99 pct after repeated HF leaching. The qualitative analysis of exhaust gases has been conducted using a Fourier transform infrared spectroscope (FTIR). The synthesized powders have been characterized using an X-ray powder diffractometer (XRD) and scanning electron microscope (SEM) techniques. The results of the reactions have been compared with equilibrium predictions performed using the FactSage 6.2 (Center for Research in Computational Thermochemistry, Montreal, Canada) thermochemical software.

A?ao?ullar?, Duygu; Balc?, Özge; Duman, Ismail; Öveço?lu, M. Lütfi

2011-06-01

297

Preparation of Boron Nitride Fibers Using Hydrated Cellulose. Part 3. Nitriding Hydrated Cellulose Fibers Impregnated with Boric Acid  

Microsoft Academic Search

The effect of preliminary heat treatment (PHT) for hydrated cellulose fibers impregnated with boric acid on the composition and structure of nitrided products is studied. Subsequent nitriding after PHT in helium leads to formation of carbon fibers coated with boron nitride, but after PHT in air there is formation of hexagonal and rhombohedral boron nitride powder. Data obtained are compared

Alexander V. Kurdyumov; N. F. Ostrovskaya; V. M. Vereshchaka

2001-01-01

298

Synthesis and characterization of radioisotope nanospheres containing two gamma emitters.  

PubMed

Silica-coated gold-silver alloy nanospheres prepared by Stöber's method were irradiated in a nuclear reactor to prepare radioisotope nanospheres for use as radiotracers. The radioisotope nanospheres included two gamma nuclides: (i) Au-198, emitting major photons with 0.412 MeV and (ii) Ag-108, emitting photons with 0.434 and 0.633 MeV. The nanospheres shell and core diameters were 100-112 nm and 20-50 nm, respectively, depending on their preparation. The gamma-emitting nanospheres could be used as tracers in high-temperature petrochemical and refinery processes in which conventional organic radioactive labels will decompose. PMID:23037922

Jung, Jin-Hyuck; Jung, Sung-Hee; Kim, Sang-Ho; Choi, Seong-Ho

2012-09-06

299

Evaluation of medical isotope production with the accelerator production of tritium (APT) facility  

SciTech Connect

The accelerator production of tritium (APT) facility, with its high beam current and high beam energy, would be an ideal supplier of radioisotopes for medical research, imaging, and therapy. By-product radioisotopes will be produced in the APT window and target cooling systems and in the tungsten target through spallation, neutron, and proton interactions. High intensity proton fluxes are potentially available at three different energies for the production of proton- rich radioisotopes. Isotope production targets can be inserted into the blanket for production of neutron-rich isotopes. Currently, the major production sources of radioisotopes are either aging or abroad, or both. The use of radionuclides in nuclear medicine is growing and changing, both in terms of the number of nuclear medicine procedures being performed and in the rapidly expanding range of procedures and radioisotopes used. A large and varied demand is forecast, and the APT would be an ideal facility to satisfy that demand.

Benjamin, R.W. [Westinghouse Savannah River Company, Aiken, SC (United States); Frey, G.D.; McLean, D.C., Jr; Spicer, K.M.; Davis, S.E.; Baron, S.; Frysinger, J.R. [Medical Univ. of South Carolina, Charleston, SC (United States); Blanpied, G.; Adcock, D. [South Carolina Univ., Columbia, SC (United States)

1997-07-10

300

Radioisotope production facility for use with positron emission tomography  

SciTech Connect

This patent describes a system for producing radionuclides for use with positron emission tomography (PET). It comprises a source of ions for producing a {sup 3}He++ beam at a low energy; radio frequency quadrupole (RFQ) accelerator means for accelerating the {sup 3}He{sup ++} beam to an energy level of about 8 MeV; and a target system having a selected target compound therein irradiated with the accelerated {sup 3}He{sup ++} beam to produce at least one radionuclide having application to PET.

Dabiri, A.E.; Hagan, W.K.

1991-08-06

301

Boron Nutrition and Boron Application in Crops  

Microsoft Academic Search

India is a predominantly vegetarian country but per capita vegetable consumption is not up to the desired national standards\\u000a due to low productivity. Though introduction of F-1 hybrids in recent times has resulted in substantial yield increase, the\\u000a full genetic yield potential could not be realized, due to several yield limiting factors including nutrient deficiencies.\\u000a Though cauliflower is temperate in

M. Edward Raja

302

Concept for a Radioisotope Powered Dual Mode Lunar Rover  

NASA Astrophysics Data System (ADS)

Over three decades ago, the Apollo missions manifestly demonstrated the value of a lunar rover to expand the exploration activities of lunar astronauts. The stated plan of the new Vision for Space Exploration to establish a permanent presence on the moon in the next decades gives new impetus to providing long range roving and exploration capability in support of the siting, construction, and maintenance of future human bases. The incorporation of radioisotope power systems and telerobotic capability in the design has the potential to significantly expand the capability of such a rover, allowing continuous operation during the full lunar day/night cycle, as well as enabling exploration in permanently shadowed regions that may be of interest to humans for the resources they may hold. This paper describes a concept that builds on earlier studies originated in the Apollo program for a Dual Mode (crewed and telerobotic) Lunar Roving Vehicle (DMLRV). The goal of this vehicle would be to provide a multipurpose infrastructure element and remote science platform for the exploration of the moon. The DMLRV would be essential for extending the productivity of human exploration crews, and would provide a unique capability for diverse long-range, long-duration science exploration between human visits. With minimal reconfiguration this vehicle could also provide the basic platform to support a range of site survey and preparation activities in anticipation of the establishment of a permanent human presence on the moon. A conceptual design is presented for the DMLRV, including discussion of mission architecture, vehicle performance, representative science payload accommodation, and equipment and crew radiation considerations.

Elliott, John O.; Schriener, Timothy M.; Coste, Keith

2006-01-01

303

Boron Stimulates Yeast (Saccharomyces cerevisiae) Growth  

Microsoft Academic Search

Boron is required for the growth of vascular plants and embryonic development in fish. The molecular basis of boron's essentiality, however, remains unknown for both. The objective of this study was to determine whether yeast (Saccharomyces cerevisiae) could be used as a model for the evaluation of intracellular boron traffick- ing. Three experiments were conducted to assess the ef- fect

A. Bennett; R. I. Rowe; N. Soch; C. D. Eckhert

304

NEW ADVANCES IN BORON SOIL CHEMISTRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Boron is an essential micronutrient element required for plant growth. Boron deficiency is wide-spread in crop plants throughout the world especially in coarse-textured soils in humid areas. Boron toxicity can also occur, especially in arid regions under irrigation. Plants respond directly to the...

305

Boron removal from seawater desalination by RO  

Microsoft Academic Search

Although a number of papers describing the boron removal methods from seawater in the past decades, the reverse osmosis (RO) for boron removal from seawater desalination is consider as one of the simplest and most promising methods. The new progresses on boron removal from seawater by RO membranes and its major effect parameter including operating temperature, operating pressure, solution pH,

Daolin Gao; Yafei Guo; Shiqiang Wang; Tianlong Deng

2011-01-01

306

Problems of designing radioisotope thermoelectric power generators with a service life of decades for use in outer space exploration vehicles  

NASA Astrophysics Data System (ADS)

The present work deals with the feasibility of developing a radioisotope thermoelectric power generator (RTPG) capable of operating unattended in outer space over a period of several decades, among other things, on the basis of chemical compounds that occur in meteoric matter. The possibilities for solving problems related to the production of three-dimensional materials and to thermoelement interconnections are discussed. The implementation of nanotechnology will allow one to achieve an increase in the efficiency of a RTPG by 15% and higher.

Prilepo, Yu. P.; Pustovalov, A. A.; Sinyavskiy, V. V.; Sudak, N. M.; Yatsenko, O. B.

2012-12-01

307

Radioisotope electric propulsion of sciencecraft to the outer solar system and near-interstellar space  

Microsoft Academic Search

Recent results are presented in the study of radioisotope electric propulsion as a near-term technology for sending small robotic sciencecraft to the outer Solar System and near- interstellar space. Radioisotope electric propulsion (REP) systems are low-thrust, ion propulsion units based on radioisotope electric generators and ion thrusters. Powerplant specific masses are expected to be in the range of 100 to

Robert J. Noble

1999-01-01

308

Boron recovery, application and economic significance: A review  

Microsoft Academic Search

Boron compounds are widely used raw materials in various industries. However, high boron concentration in aqueous systems may be harmful to both humans and plants. Many treatment technologies have shown wide limitations in the removal of boron from wastewater and boronic wastes due to the complex boron chemistry. Boron exists as boric acid at pH9.2. Recovery of boron is one

Ezerie Henry Ezechi; Mohamed Hasnain Isa; Shamsul Rahman Kutty; Nasiman B. Sapari

2011-01-01

309

First-Principles Investigation on Boron Nanostructures  

NASA Astrophysics Data System (ADS)

First-principles calculations based on density functional theory are employed to study and predict the properties of boron and Mg boride nanostructures. For boron nanostructures, two-dimensional boron sheets are found to be metallic and made of mixtures of triangles and hexagons which benefit from the balance of two-center bonding and three-center bonding. This unusual bonding in boron sheets results in a self-doping picture where adding atoms to the hexagon centers does not change the number of bonding states but merely increases the electron count. Boron sheets can be either flat or buckled depending on the ratio between hexagons and triangles. Formed by stacking two identical boron sheets, double-layered boron sheets can form interlayer bonds, and the most stable one is semiconducting. Built from single-layered boron sheets, single-walled boron nanotubes have smaller curvature energies than carbon nanotubes and undergo a metal-to-semiconductor transition once the diameter is smaller than ˜20 A. Optimal double-walled boron nanotubes with inter-walled bonds formed are metallic and always more stable than single-walled ones. For Mg boride nanostructures, certain Mg boride sheets prefer to curve themselves into nanotubes, which is explained via Mg-Mg interactions governed by the charge state of Mg. In addition, optimal Mg boride sheet structures are explored with a genetic algorithm. Phase diagrams for Mg boride sheet structures are constructed and stable phases under boron-rich environments are identified. Curvature effects on the phase diagram of Mg boride nanotubes are also discussed. As a natural extension to boron sheets, layered boron crystals based on boron sheets are then presented and are shown to be stable under high pressure. Finally, this thesis ends with an investigation of hydrogen-storage properties of pristine and metal doped boron nanostructures.

Tang, Hui

310

Radioisotope thermoelectric generator licensed hardware package and certification tests  

Microsoft Academic Search

This paper presents the Licensed Hardware package and the Certification Test portions of the Radioisotope Thermoelectric Generator Transportation System. This package has been designed to meet those portions of the Code of Federal Regulations (10 CFR 71) relating to 'Type B' shipments of radioactive materials. The detailed information for the anticipated license is presented in the safety analysis report for

L. H. Goldmann; H. S. Averette

1994-01-01

311

Assembly of radioisotope power systems at Westinghouse Hanford Company  

SciTech Connect

Long-term space flight requires reliable long-term power sources. For the purpose of supplying a constant supply of power in deep space, the radioisotope thermoelectric generator has proven to be a successful power source. Westinghouse Hanford Company is installing the Radioisotope Power Systems Facility which is located in the Fuels and Material Examination Facility on the Hanford Site near Richland, Washington, for assembling the generators. The radioisotope thermoelectric generator assembly process is base upon one developed at Mound Laboratory in Miamisburg, Ohio (presently operated by EG G Mound Applied Technologies). Westinghouse Hanford Company is modernizing the process to ensure the heat source assemblies are produced in a manner that maximizes operator safety and is consistent with today's environmental and operational safety standards. The facility is being prepared to assemble the generators required by the National Aeronautics and Space Administration missions for CRAF (Comet Rendezvous Asteroid Flyby) in 1995 and Cassini, an investigation of Saturn and its moons, in 1996. The facility will also have the capability to assemble larger radioisotope power generators designed for dynamic power generation. 4 refs., 11 figs.

Alderman, C.J.

1990-04-01

312

Radioisotope-Powered Hopper Design for Europan Mission  

Microsoft Academic Search

NASA and ESA have prioritized an outer planet flagship mission to Jupiter and its four largest moons. The constant cycling of material from Europa's surface to the global ocean below allows the potential for organic life similar to the eco-systems surrounding geothermal vents on Earth. The Europa Hopper model utilizes a radioisotope core, in-situ materials and a subsurface ice probe

Justin Dekany; Melissa Guzman; Karthikeyan Jagadevan; Jonathan McCulley; Kevin Shipley; Steven Howe

2010-01-01

313

An Advanced Turbo-Brayton Converter for Radioisotope Power Systems  

Microsoft Academic Search

Past work has shown that Brayton power converters are an attractive option for high power, long-duration space missions. More recently, Creare has shown that Brayton technology could be scaled with high efficiency and specific power to lower power levels suitable for radioisotope power conversion systems. Creare is currently leading the development of an advanced turbo-Brayton converter under NASA's Prometheus Program.

Mark V. Zagarola; Michael G. Izenson; Jeffrey J. Breedlove; George M. O'Connor; Andrew C. Ketchum; Richard L. Jetley; James K. Simons

2005-01-01

314

Anthropogenic radioisotopes to estimate rates of soil redistribution by wind  

Technology Transfer Automated Retrieval System (TEKTRAN)

Erosion of soil by wind and water is a degrading process that affects millions of hectares worldwide. Atmospheric testing of nuclear weapons and the resulting fallout of anthropogenic radioisotopes, particularly Cesium 137, has made possible the estimation of mean soil redistribution rates. The pe...

315

Analytical thermal model validation for Cassini radioisotope thermoelectric generator  

Microsoft Academic Search

The Saturn-bound Cassini spacecraft is designed to rely, without precedent, on the waste heat from its three radioisotope thermoelectric generators (RTGs) to warm the propulsion module subsystem, and the RTG end dome temperature is a key determining factor of the amount of waste heat delivered. A previously validated SINDA thermal model of the RTG was the sole guide to understanding

Edward L Lin

1997-01-01

316

Radioisotope electric propulsion missions utilizing a common spacecraft design  

Microsoft Academic Search

A study was conducted that shows how a single radioisotope electric propulsion (REP) spacecraft design could be used for various missions throughout the solar system. This spacecraft design is based on an REP feasibility design from a study performed by NASA Glenn Research Center and the Johns Hopkins University Applied Physics Laboratory. The study also identifies technologies that need development

Douglas Fiehler; Steven Oleson

2005-01-01

317

DOES SALINITY REDUCE BORON’S TOXIC EFFECT IN BROCCOLI?  

Technology Transfer Automated Retrieval System (TEKTRAN)

High salinity and boron often occur together in irrigation water in arid climates, but very little research has been done to study the interaction of the two. A greenhouse experiment was conducted at the U.S. Salinity Laboratory in sand tanks to evaluate the interactions between B and saline draina...

318

Recoil-Implantation Of Multiple Radioisotopes Towards Wear Rate Measurements And Particle Tracing In Prosthetic Joints  

SciTech Connect

This study demonstrates a new method of radioisotope labeling of ultra-high molecular weight polyethylene inserts in prosthetic joints for wear studies. The radioisotopes {sup 97}Ru, {sup 100}Pd, {sup 100}Rh, and {sup 101m}Rh are produced in fusion evaporation reactions induced by {sup 12}C ions in a {sup 92}Zr target foil. The fusion products recoil-implant into ultra-high molecular weight polyethylene plugs, machined to fit into the surface of the inserts. During laboratory simulations of the joint motion, a wear rate of the labeled polyethylene may be measured and the pathways of wear debris particles can be traced by detecting characteristic gamma-rays. The concentration profiles of the radioisotopes extend effectively uniformly from the polyethylene surface to a depth of about 4 {mu}m. The multiplicity of labeling and the use of several gamma-ray lines aids with avoiding systematic measurement uncertainties. Two polyethylene plugs were labeled and one was fitted into the surface of the tibial insert of a knee prosthesis, which had been worn in. Actuation over close to 100,000 cycles with a 900 N axial load and a 24 deg. flexion angle removed (14{+-}1)% of the gamma-ray activity from the plug. Most of this activity dispersed into the serum lubricant identifying this as the important debris pathway. Less than 1% activity was transferred to the femoral component of the prosthesis and the measured activity on the tibial tray was insignificant. Assuming uniform wear across the superior surface of the insert, a wear rate of (12{+-}3) mm{sup 3}/Megacycle was determined. This is consistent with wear rate measurements under similar conditions using other techniques.

Warner, Jacob A.; Timmers, Heiko [School of Physical, Environmental and Mathematical Sciences, University of New South Wales at ADFA, Canberra, ACT 2600 (Australia); Smith, Paul N.; Scarvell, Jennifer M. [Trauma and Orthopaedic Research Unit, Canberra Hospital, PO BOX 11, Woden, ACT 2606 (Australia); Gladkis, Laura [School of Physical, Environmental and Mathematical Sciences, University of New South Wales at ADFA, Canberra, ACT 2600 (Australia); Trauma and Orthopaedic Research Unit, Canberra Hospital, PO BOX 11, Woden, ACT 2606 (Australia)

2011-06-01

319

Thermionic properties of the molybdenum boron system  

SciTech Connect

The thermionic work function has been measured as a function of composition within the various two phase regions between Mo and MoB/sub 2/. Values at the low boron and high boron phase boundaries for the various compounds were obtained by extrapolation. The following effective work functions were obtained: Mo/sub 2/B (low boron) = 3.08 eV; Mo/sub 2/B (high boron) = 3.63 eV; ..cap alpha..-MoB (low boron) = 3.38 eV; ..cap alpha..-MoB (high boron) = 4.30 eV; ..beta..-MoB (low boron) = 2.83 eV; ..beta..-MoB (high boron) = 3.92; Mo/sub 2/B/sub 3/ (low boron) = 4.65 eV; Mo/sub 2/B/sub 3/ (high boron) = 3.85 eV; and MoB/sub 2/ (low boron) = 3.52 eV. Because the composition range of these compounds is very narrow, the work function is very sensitive to the composition within the single phase regions.

Storms, E.K.

1980-01-01

320

Boron-enhanced diffusion of boron from ultralow-energy boron implantation  

SciTech Connect

The authors have investigated the diffusion enhancement mechanism of BED (boron enhanced diffusion), wherein the boron diffusivity is enhanced three to four times over the equilibrium diffusivity at 1,050 C in the proximity of a silicon layer containing a high boron concentration. It is shown that BED is associated with the formation of a fine-grain polycrystalline silicon boride phase within an initially amorphous Si layer having a high B concentration. For 0.5 keV B{sup +}, the threshold implantation dose which leads to BED lies between 3 {times} 10{sup 14} and of 1 {times} 10{sup 15}/cm{sup {minus}2}. Formation of the shallowest possible junctions by 0.5 keV B{sup +} requires that the implant dose be kept lower than this threshold.

Agarwal, A.; Eaglesham, D.J.; Gossmann, H.J.; Pelaz, L.; Herner, S.B.; Jacobson, D.C. [Lucent Technologies, Murray Hill, NJ (United States). Bell Labs.; Haynes, T.E. [Oak Ridge National Lab., TN (United States). Solid State Div.; Erokhin, Y.E. [Eaton Corp., Beverly, MA (United States)

1998-05-03

321

High-temperature reaction of aluminum oxide with boron in vacuum  

Microsoft Academic Search

The reaction of aluminum oxide with boron in vacuum was studied over a wide range of temperatures. Analysis of the reaction products was carried out by chemical, x-ray diffraction, optical, and metallographic methods. The temperature dependence of the reaction was determined. A high boron phase of the composition AlB18–31 is produced by the borothermic reduction of aluminum oxide. The crystalline

A. I. Kharlamov; V. V. Fomenko; N. V. Kirillova

1996-01-01

322

Assessment of DNA integrity (COMET assay) in sperm cells of boron-exposed workers  

Microsoft Academic Search

An extension of a male reproductive study conducted in a boric acid\\/borate production zone at Band?rma, Turkey, is presented.\\u000a The relation between DNA-strand breaks (COMET assay, neutral and alkaline version) in sperm cells and previously described\\u000a sperm quality parameters was investigated in boron-exposed males. A correlation between blood boron levels and mean DNA-strand\\u000a breaks in sperm was weak, and DNA-strand

Yalç?n Duydu; Nur?en Ba?aran; Aylin Üstünda?; Sevtap Ayd?n; Ülkü Ünde?er; Osman Yavuz Ataman; Kaan Aydos; Yalç?n Düker; Katja Ickstadt; Britta Schulze Waltrup; Klaus Golka; Hermann M. Bolt

323

Removal of boron from wastewater by the hydroxyapatite formation reaction using acceleration effect of ammonia.  

PubMed

The mechanism was discussed for the removal of boron by the hydroxyapatite (HAp) formation reaction using Ca(OH)(2) and (NH(4))(2)HPO(4) in room temperature. Time required to remove boron was 20 min by adding Ca(OH)(2) and (NH(4))(2)HPO(4) for the remaining boron to below 1mg/L. The removal rate of boron was controlled by the HAp precipitate formation and the presence of ammonia. From the XRD patterns and SEM images, HAp could be confirmed in the precipitate product. The reaction between borate ions and calcium hydroxide was accelerated by dehydration with ammonia; the borate-calcium hydroxide compound coprecipitated with resulting HAp. Although the removal of boron decreased in the presence of sulfate, phosphate, and aluminum, these effects could be prevented by adding excess Ca(OH)(2). Interference of fluoride ions was eliminated by adding Al(3+). Sodium alpha-olefin sulfonate was the most effective coagulant for HAp precipitation. The proposed boron removal method has several advantages about treating time and ability of boron removal. The method was successfully applied to the real hot spring wastewater. PMID:22981286

Yoshikawa, Eishi; Sasaki, Atsushi; Endo, Masatoshi

2012-08-25

324

TMI2 fission product inventory estimates (draft)  

Microsoft Academic Search

This report presents the results of analyses performed to estimate the inventory and distribution of selected radioisotopes within the TMI-2 reactor system. The intent of the report is to document the method used in estimating the fission product inventory and associated uncertainties. The values presented should be viewed as preliminary. Selected radioisotopes for which best-estimate inventories and uncertainties are presented

E. L. Tolman; M. Nishio

1987-01-01

325

Californium-252: a remarkable versatile radioisotope.  

National Technical Information Service (NTIS)

A product of the nuclear age, Californium-252 ((sup 252)Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux...

I. W. Osborne-Lee C. W. Alexander

1995-01-01

326

A detailed examination of boronic acid–diol complexation  

Microsoft Academic Search

Boronic acids bind with compounds containing diol moieties with high affinity through reversible boronate formation. However, the conditions that foster tight binding between the diol and the boronic acid are not well understood. Also, due to the multiple ionic states of both the boronic acid and boronate ester, the equilibrium constants reported in the literature have not always been strictly

Greg Springsteen; Binghe Wang

2002-01-01

327

Rhombohedral crystal structure of compounds containing boron-rich icosahedra  

Microsoft Academic Search

The crystal structures of several icosahedral boron containing compounds have been refined using Mo K? intensity data. Though these compounds, ?-boron, boron carbide, boron phosphide and boron arsenide, differ chemically, all have the same basic rhombohedral structure. The structures consist of icosahedral units bonded together with direct B-B bonds as well as other linkage units. Similarities in electron distributions are

B. Morosin; A. W. Mullendore; D. Emin; G. A. Slack

1986-01-01

328

Rhombohedral crystal structure of compounds containing boron-rich icosahedra  

Microsoft Academic Search

The crystal structures of several icosahedral boron containing compounds have been refined using Mo Kalpha intensity data. Though these compounds, alpha-boron, boron carbide, boron phosphide and boron arsenide, differ chemically, all have the same basic rhombohedral structure. The structures consist of icosahedral units bonded together with direct B-B bonds as well as other linkage units. Similarities in electron distributions are

B. Morosin; A. W. Mullendore; D. Emin; G. A. Slack

1986-01-01

329

Boron in plant cell walls  

Microsoft Academic Search

Boron is an essential element for higher plants, yet the primary functions remain unclear. In intact tissues of higher plants, this element occurs as both water soluble and water insoluble forms. In this review, the intracellular localisation of B and possible function of B in cell walls of higher plants are discussed. The majority of the water soluble B seems

Toru Matoh

1997-01-01

330

Reactions of boron with soils  

Microsoft Academic Search

Boron is an essential micronutrient for plants, but the range between deficient and toxic B concentration is smaller than for any other nutrient element. Plants respond directly to the activity of B in soil solution and only indirectly to B adsorbed on soil constituents. Soil factors affecting availability of B to plants are: pH, texture, moisture, temperature, organic matter and

Sabine Goldberg

1997-01-01

331

The boron acceptor in diamond  

NASA Astrophysics Data System (ADS)

To date, the only dopant available for bulk diamond with good controllability is boron, which acts as an acceptor and can be incorporated in relatively high concentrations, allowing the design of devices for electronic applications. This paper summarizes data on doping procedures and on optical and electrical properties.

Thonke, Klaus

2003-03-01

332

Boron translocation in coffee trees  

Microsoft Academic Search

Boron deficiency in coffee trees (Coffea arabica) is widespread, however, responses to B fertilizer have been erratic, depending on the year, method, and time of application. A better understanding of B uptake, distribution, and remobilization within the plant is important in developing a rational fertilization program. Field\\u000a and greenhouse experiments were conducted to study B distribution and remobilization in coffee

Vagner M. Leite; Patrick H. Brown; Ciro A. Rosolem

2007-01-01

333

Method of separating boron isotopes  

DOEpatents

A method of boron isotope enrichment involving the isotope preferential photolysis of (2-chloroethenyl)-dichloroborane as the feed material. The photolysis can readily by achieved with CO/sub 2/ laser radiation and using fluences significantly below those required to dissociate BCl/sub 3/.

Jensen, R.J.; Thorne, J.M.; Cluff, C.L.

1981-01-23

334

Metallization on Cubic Boron Nitride.  

National Technical Information Service (NTIS)

Cubic boron nitride was immersed in molten alloys of Cu-Ti, Ag-Ti, Cu-Ag-Ti and Cu-Sn-Ti after which the specimens were examined in an electron microprobe analyzer for penetration of Cu and Ti. Metallographic examination was employed in the study of phase...

Y. V. Naidich A. S. Vishrevskii G. A. Kolesnichendi E. M. Chistyakov E. D. Yakunova

1974-01-01

335

A search for boron in damped Ly? systems  

NASA Astrophysics Data System (ADS)

We present the first systematic study of boron beyond the Local Group. This analysis is performed on a sample of 30 damped Ly? systems (DLAs) with strong metal lines, which are expected to trace the interstellar medium of high-z galaxies. We report on two boron detections at >3? significance; one new detection and one confirmation. The ratios of B/O and, for the first time, B/S are compared with previous stellar and interstellar measurements in the Milky Way and Small Magellanic Cloud. The novel comparison with sulphur, which tracks oxygen's abundance, alleviates the uncertainty associated with stellar oxygen measurements. For both detections, the inferred B/S ratio is in excess of the prediction of primary boron production from spallation processes. Possible sources of contamination are discussed, as well as physical effects that could impact the observed ratios. However taken at face value, the implication of these measurements suggests potentially higher cosmic ray fluxes in DLAs. The prospects for future boron detections in other high-redshift DLAs to confirm our results is also discussed.

Berg, Trystyn A. M.; Ellison, Sara L.; Venn, Kim A.; Prochaska, J. Xavier

2013-10-01

336

Cleavage of P?O in the Presence of P-N: Aminophosphine Oxide Reduction with In Situ Boronation of the P(III) Product.  

PubMed

In contrast to tertiary phosphine oxides, the deoxygenation of aminophosphine oxides is effectively impossible due to the need to break the immensely strong and inert P?O bond in the presence of a relatively weak and more reactive P?N bond. This long-standing problem in organophosphorus synthesis is solved by use of oxalyl chloride, which chemoselectively cleaves the P?O bond forming a chlorophosphonium salt, leaving the P?N bond(s) intact. Subsequent reduction of the chlorophosphonium salt with sodium borohydride forms the P(III) aminophosphine borane adduct. This simple one-pot procedure was applied with good yields for a wide range of P?N-containing phosphoryl compounds. The borane product can be easily deprotected to produce the free P(III) aminophosphine. Along with no observed P?N bond cleavage, the use of sodium borohydride also permits the presence of ester functional groups in the substrate. The availability of this methodology opens up previously unavailable synthetic options in organophosphorus chemistry, two of which are exemplified. PMID:24027002

Kenny, Niall P; Rajendran, Kamalraj V; Jennings, Elizabeth V; Gilheany, Declan G

2013-09-11

337

Global biogeochemical cycle of boron  

NASA Astrophysics Data System (ADS)

The global Boron (B) cycle is primarily driven by a large flux (1.44 Tg B/yr) through the atmosphere derived from seasalt aerosols. Other significant sources of atmospheric boron include emissions during the combustion of biomass (0.26-0.43 Tg B/yr) and coal, which adds 0.20 Tg B/yr as an anthropogenic contribution. These known inputs to the atmosphere cannot account for the boron removed from the atmosphere during rainfall (3.0 Tg B/yr) and estimated dry deposition (1.3-2.7 Tg B/yr). In addition to atmospheric deposition, rock weathering is a source of boron (0.19 Tg B/yr) for terrestrial ecosystems, and humans mine about 0.31 Tg B/yr from the Earth's crust. More than 4.8 Tg B/yr circulates in the biogeochemical cycle of land plants, and about 0.53-0.63 Tg B/yr is carried from land to sea by rivers. The biogeochemical cycle of boron in the sea includes 4.4 Tg B/yr circulating in the marine biosphere, and an annual loss of 0.47 Tg B/yr to the oceanic crust via a variety of sedimentary processes that collectively remove only a small fraction of the total annual inputs to the oceans. Thus with our current understanding of the global biogeochemistry of B, the atmospheric budget shows outputs > inputs, while the marine compartments show inputs > outputs. Despite these uncertainties, it is clear that the human perturbation of the global B cycle has more than doubled the mobilization of B from the crust and contributes significantly to the B transport in rivers.

Park, Haewon; Schlesinger, William H.

2002-12-01

338

First-principles studies of boron nanostructures  

NASA Astrophysics Data System (ADS)

Boron is an 'electron deficient' element which has a rather fascinating chemical versatility. In the solid state, the elemental boron has neither a pure covalent nor a pure metallic character. As a result, its vast structural dimensionality and peculiar bonding features hold a unique place among other elements in the periodic table. In order to understand and properly describe these unusual bonding features, a detailed and systematic theoretical study is needed. In this work, I will show that some of the qualitative features of boron nanostructures, including clusters, sheets and nanotubes can easily be extracted from the results of first principles calculations based on density functional theory. Specifically, the size-dependent evolution of topological structures and bonding characteristics of boron clusters, Bn will be discussed. Based on the scenario observed in the boron clusters, the unique properties of boron sheets and boron nanotubes will be described. Moreover, the ballistic electron transport in single-walled boron nanotube relative to that of single-walled carbon nanotubes will be considered. It is expected that the theoretical results obtained in the present thesis will initiate further studies on boron nanostructures, which will be helpful in understanding, designing and realizing boron-based nanoscale devices.

Lau, Kah Chun

339

Ferromagnetism and semiconducting of boron nanowires.  

PubMed

More recently, motivated by extensively technical applications of carbon nanostructures, there is a growing interest in exploring novel non-carbon nanostructures. As the nearest neighbor of carbon in the periodic table, boron has exceptional properties of low volatility and high melting point and is stronger than steel, harder than corundum, and lighter than aluminum. Boron nanostructures thus are expected to have broad applications in various circumstances. In this contribution, we have performed a systematical study of the stability and electronic and magnetic properties of boron nanowires using the spin-polarized density functional calculations. Our calculations have revealed that there are six stable configurations of boron nanowires obtained by growing along different base vectors from the unit cell of the bulk ?-rhombohedral boron (?-B) and ?-rhombohedral boron (?-B). Well known, the boron bulk is usually metallic without magnetism. However, theoretical results about the magnetic and electronic properties showed that, whether for the ?-B-based or the ?-B-based nanowires, their magnetism is dependent on the growing direction. When the boron nanowires grow along the base vector [001], they exhibit ferromagnetism and have the magnetic moments of 1.98 and 2.62 ?B, respectively, for the ?-c [001] and ?-c [001] directions. Electronically, when the boron nanowire grows along the ?-c [001] direction, it shows semiconducting and has the direct bandgap of 0.19 eV. These results showed that boron nanowires possess the unique direction dependence of the magnetic and semiconducting behaviors, which are distinctly different from that of the bulk boron. Therefore, these theoretical findings would bring boron nanowires to have many promising applications that are novel for the boron bulk. PMID:23244063

Li, Jiling L; He, Tao; Yang, Guowei

2012-12-17

340

Ferromagnetism and semiconducting of boron nanowires  

NASA Astrophysics Data System (ADS)

More recently, motivated by extensively technical applications of carbon nanostructures, there is a growing interest in exploring novel non-carbon nanostructures. As the nearest neighbor of carbon in the periodic table, boron has exceptional properties of low volatility and high melting point and is stronger than steel, harder than corundum, and lighter than aluminum. Boron nanostructures thus are expected to have broad applications in various circumstances. In this contribution, we have performed a systematical study of the stability and electronic and magnetic properties of boron nanowires using the spin-polarized density functional calculations. Our calculations have revealed that there are six stable configurations of boron nanowires obtained by growing along different base vectors from the unit cell of the bulk ?-rhombohedral boron (?-B) and ?-rhombohedral boron (?-B). Well known, the boron bulk is usually metallic without magnetism. However, theoretical results about the magnetic and electronic properties showed that, whether for the ?-B-based or the ?-B-based nanowires, their magnetism is dependent on the growing direction. When the boron nanowires grow along the base vector [001], they exhibit ferromagnetism and have the magnetic moments of 1.98 and 2.62 ?B, respectively, for the ?-c [001] and ?-c [001] directions. Electronically, when the boron nanowire grows along the ?-c [001] direction, it shows semiconducting and has the direct bandgap of 0.19 eV. These results showed that boron nanowires possess the unique direction dependence of the magnetic and semiconducting behaviors, which are distinctly different from that of the bulk boron. Therefore, these theoretical findings would bring boron nanowires to have many promising applications that are novel for the boron bulk.

Li, Jiling L.; He, Tao; Yang, Guowei

2012-12-01

341

In Situ Observation of Phase Transformation in Low-Carbon, Boron-Treated Steels  

NASA Astrophysics Data System (ADS)

It is known that adding the appropriate amount of boron to steels dramatically increases their hardness and toughness as a result of the transition of the microstructure from grain boundary nucleation to intragranular nucleation. In this study, precipitation and phase transformation kinetics in heat-affected zones of low-carbon, boron-treated steels are observed directly by high-temperature laser scanning confocal microscopy. The effects of boron content and austenite grain size on the phase transformation process are investigated systematically by quantifying the transformation product, the transformation start temperature, the average length of the ferrite plates, and the average number of potent nucleation sites. Finally, detailed methods for controlling and optimizing the microstructure in the heat-affected zones of low-carbon, boron-treated steels are discussed.

Zhang, Di; Shintaku, Yoshiaki; Suzuki, Shuichi; Komizo, Yu-Ichi

2012-02-01

342

Californium-252: a remarkable versatile radioisotope  

SciTech Connect

A product of the nuclear age, Californium-252 ({sup 252}Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, {sup 252}Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of {sup 252}Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the {sup 252}Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, {sup 252}Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of {sup 252}Cf from ORNL is summarized herein.

Osborne-Lee, I.W.; Alexander, C.W.

1995-10-10

343

Longitudinal Splitting of Boron Nitride Nanotubes for the Facile Synthesis of High Quality Boron Nitride Nanoribbons.  

National Technical Information Service (NTIS)

Boron nitride nanoribbons (BNNRs), the boron nitride structural equivalent of graphene nanoribbons (GNRs), are predicted to possess unique electronic and magnetic properties. We report the synthesis of BNNRs through the potassium-intercalation-induced lon...

A. Sinitskii A. L. Gibb K. J. Erickson M. Rousseas N. Alem

2011-01-01

344

Environmental assessment for radioisotope heat source fuel processing and fabrication  

SciTech Connect

DOE has prepared an Environmental Assessment (EA) for radioisotope heat source fuel processing and fabrication involving existing facilities at the Savannah River Site (SRS) near Aiken, South Carolina and the Los Alamos National Laboratory (LANL) near Los Alamos, New Mexico. The proposed action is needed to provide Radioisotope Thermoelectric Generators (RTG) to support the National Aeronautics and Space Administration's (NASA) CRAF and Cassini Missions. Based on the analysis in the EA, DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, an Environmental Impact Statement is not required. 30 refs., 5 figs.

Not Available

1991-07-01

345

Radioisotope power system options for future planetary missions  

NASA Astrophysics Data System (ADS)

Like previous missions to the outer planets, future spacecraft missions such as Pluto/Kuiper Express, Europa Orbiter, and Solar Probe will require radioisotope power systems for their long voyages away from the Sun. Several candidate advanced power conversion technologies have been proposed that have been proposed that have higher power conversion efficiencies than the traditional thermoelectric generators, with the potential for reduced mass and reduced quantities of nuclear fuel required. Studies conducted by Lockheed Martin under the direction of the Department of Energy have included the development of system conceptual designs utilizing Alkali Metal to Electric Conversion (AMTEC) and Stirling power conversion. Generator concepts based on these conversion technologies are compared in this paper with an alternative Small RTG, based on the General Purpose Heat Source-Radioisotope Thermoelectric Generator (GPHS-RTG). .

Cockfield, Robert D.

2001-02-01

346

Low Temperature Growth of Boron Nitride Nanotubes on Substrates  

SciTech Connect

High growth temperatures (>1100 C), low production yield, and impurities have prevented research progress and applications of boron nitride nanotubes (BNNTs) in the past 10 years. Here, we show that BNNTs can be grown on substrates at 600 C. These BNNTs are constructed of high-order tubular structures and can be used without purification. Tunneling spectroscopy indicates that their band gap ranges from 4.4 to 4.9 eV.

Wang, Jiesheng [Michigan Technological University; Kayastha, V. K. [Michigan Technological University; Yap, Y. K. [Michigan Technological University; Fan, Zhlyong [University of California, Irvine; Lu, Jia G. [University of California, Irvine; Pan, Zhengwei [ORNL; Ivanov, Ilia N [ORNL; Puretzky, Alexander A [ORNL; Geohegan, David B [ORNL

2005-01-01

347

Effective use of neodymium iron boron magnets, case studies  

Microsoft Academic Search

Magnets based on neodymium iron boron (NdFeB) alloys have been available for about 15 years, yet many people are frustrated in their attempts to incorporate this material into new devices. These are problems that cannot be solved by research focused on higher energy product materials, nor are they the result of the three well-known objections to NdFeB magnets: higher cost

S. R. Trout; Yuriy Zhilichev

1999-01-01

348

Promising applications of neodymium boron Iron magnets in electrical machines  

Microsoft Academic Search

Neodymium Boron IronNdBFemagnets have high energy product with suitable magnetic and physical properties for applications in electrical machines. The design aspects of permanent magnet machines using NdBFe magnets are presented. The ranges of applica? tions cover both generators and motors up to 200 kW ratings. The exciting combination with micro? computers and power electronics makes the permanent magnet motors truly

M. A. Rahman; Gordon R. Slemon

1985-01-01

349

Final design review of boron carbide safety rod  

SciTech Connect

The object of this paper discusses the design review of the boron carbide safety rod for the Westinghouse Savannah River Company. This paper reviewed information presented by personnel of the Savannah River Laboratory (SRL) Equipment Engineering Section, SRL Materials Technology Section and Reactor Materials Engineering and Technology. From this report, views, opinions and recommendations were made on the safety rod from materials testing to production.

Lutz, R.N.

1991-09-24

350

Behavior of Boron Doped Graphites and Boron Carbide under Ion Beam and Plasma Irradiation  

Microsoft Academic Search

\\u000a The paper shortly describes the methods of boron carbide coating deposition and presents the experimental results characterizing\\u000a the properties of boron carbide coatings and of boron doped graphites important to their application as the plasma facing\\u000a materials of fusion devices and other plasma apparatus dealing with dense and high temperature plasma. Conclusion is made\\u000a that thick renewable boron carbide coating

L. B. Begrambekov; O. I. Buzhinsky; A. Zakharovi

2011-01-01

351

Behavior of Boron Doped Graphites and Boron Carbide under Ion Beam and Plasma Irradiation  

NASA Astrophysics Data System (ADS)

The paper shortly describes the methods of boron carbide coating deposition and presents the experimental results characterizing the properties of boron carbide coatings and of boron doped graphites important to their application as the plasma facing materials of fusion devices and other plasma apparatus dealing with dense and high temperature plasma. Conclusion is made that thick renewable boron carbide coating can successfully be used as the protecting coating of plasma facing elements of ITER.

Begrambekov, L. B.; Buzhinsky, O. I.; Zakharovi, A.

352

Radioisotope thermoelectric generator transportation system subsystem 143 software development plan  

NASA Astrophysics Data System (ADS)

This plan describes the activities to be performed and the controls to be applied to the process of specifying, developing, and qualifying the data acquisition software for the Radioisotope Thermoelectric Generator (RTG) Transportation System Subsystem 143 Instrumentation and Data Acquisition System (IDAS). This plan will serve as a software quality assurance plan, a verification and validation (V and V) plan, and a configuration management plan.

King, D. A.

1994-11-01

353

Plastic Gamma Sensors: An Application in Detection of Radioisotopes  

SciTech Connect

A brief survey of plastic scintillators for various radiation measurement applications is presented here. The utility of plastic scintillators for practical applications such as gamma radiation monitoring, real-time radioisotope detection and screening is evaluated in laboratory and field measurements. This study also reports results of Monte Carlo-type predictive responses of common plastic scintillators in gamma and neutron radiation fields. Small-size plastic detectors are evaluated for static and dynamic gamma-ray detection sensitivity of selected radiation sources.

S. Mukhopadhyay

2003-06-01

354

XRF induced by PIXE: Comparison with radioisotope XRF  

Microsoft Academic Search

XRF induced by PIXE (XRF-PIXE) using silver as a primary target was compared with a standard radioisotope XRF system using Cd-109 as a primary exciting source, for the analysis of single-element thin standards. The sensitivity of the two methods were determined for elements from Cl to Mo. XRF is found to be more sensitive for elements from Cl to Mn,

K. A. Al-Saleh; J. D. Meyer; N. S. Saleh

1987-01-01

355

Radioisotope Concentration in Lake Sediments of Maracaibo, Venezuela  

NASA Astrophysics Data System (ADS)

Maracaibo Lake is one of the most important water basing and oil producing regions in Venezuela. Changes in the local environment have been monitored for chemical pollution in the past. For this study we selected a set of sediment samples collected in the shore and analyzed for its radioisotope content. Results show the gamma emitting isotopes distribution. Isotopes concentrations have been determined within the natural K, Th and U families.

Salas, A. Rangel; Viloria, T.; Sajo-Bohus, L.; Barros, H.; Greaves, E. D.; Palacios, D.

2007-10-01

356

Radioisotope investigation of continuous bladder irrigation after transurethral resection.  

PubMed

Radioisotope studies using 131I serum albumin were performed on 20 patients to investigate the possibility of intravascular absorption of the irrigating solution during continuous bladder irrigation after transurethral resection of the prostate. In only 5 of 20 patients was a minimal absorption of 1 to 34 cc observed. On the basis of these studies the routine use of continuous bladder irrigation after transurethral resection can be recommended, provided techniques are sterile. PMID:62061

Frohmuller, H G; Ackermann, R

1976-11-01

357

Radioisotope Concentration in Lake Sediments of Maracaibo, Venezuela  

SciTech Connect

Maracaibo Lake is one of the most important water basing and oil producing regions in Venezuela. Changes in the local environment have been monitored for chemical pollution in the past. For this study we selected a set of sediment samples collected in the shore and analyzed for its radioisotope content. Results show the gamma emitting isotopes distribution. Isotopes concentrations have been determined within the natural K, Th and U families.

Salas, A. Rangel; Viloria, T. [La Universidad del Zulia (Venezuela); Sajo-Bohus, L.; Barros, H.; Greaves, E. D.; Palacios, D. [Universidad Simon Bolivar (Venezuela)

2007-10-26

358

An Advanced Turbo-Brayton Converter for Radioisotope Power Systems  

Microsoft Academic Search

Past work has shown that Brayton power converters are an attractive option for high power, long-duration space missions. More recently, Creare has shown that Brayton technology could be scaled with high efficiency and specific power to lower power levels suitable for radioisotope power conversion systems. Creare is currently leading the development of an advanced turbo-Brayton converter under NASA’s Prometheus Program.

Mark V. Zagarola; Michael G. Izenson; Jeffrey J. Breedlove; George M. O’Connor; Andrew C. Ketchum; Richard L. Jetley; James K. Simons

2005-01-01

359

Method for preparing boron-carbide articles  

DOEpatents

The invention is directed to the preparation of boron carbide articles of various configurations. A stoichiometric mixture of particulate boron and carbon is confined in a suitable mold, heated to a temperature in the range of about 1250 to 1500$sup 0$C for effecting a solid state diffusion reaction between the boron and carbon for forming the boron carbide (B$sub 4$C), and thereafter the resulting boron-carbide particles are hot-pressed at a temperature in the range of about 1800 to 2200$sup 0$C and a pressure in the range of about 1000 to 4000 psi for densifying and sintering the boron carbide into the desired article.

Benton, S.T.; Masters, D.R.

1975-10-21

360

Structural Study of alpha-Rhombohedral Boron at High Pressures  

Microsoft Academic Search

Recently, it has been shown that, like beta-rhombohedral boron (beta-boron), alpha-rhombohedral boron (alpha-boron) exhibits superconductivity at high pressure. The transition pressure is similar to that of beta-boron, that is, about 160 GPa. This paper presents a theoretical and experimental study of the structural change in alpha-boron at high pressures. High-pressure (up to 200 GPa) X-ray experiments were performed at a

Koun Shirai; Haruhiko Dekura; Yoshihisa Mori; Yutaka Fujii; Hiroshi Hyodo; Kaoru Kimura

2011-01-01

361

Energy Landscape of Fullerene Materials: A Comparison of Boron to Boron Nitride and Carbon  

Microsoft Academic Search

Using the minima hopping global geometry optimization method on the density functional potential energy surface we show that the energy landscape of boron clusters is glasslike. Larger boron clusters have many structures which are lower in energy than the cages. This is in contrast to carbon and boron nitride systems which can be clearly identified as structure seekers. The differences

Sandip de; Alexander Willand; Maximilian Amsler; Pascal Pochet; Luigi Genovese; Stefan Goedecker

2011-01-01

362

ZIRCONIUM DIBORIDE, BORON NITRIDE, AND BORON CARBIDE COMPATIBILITY WITH AUSTENITIC STAINLESS STEEL  

Microsoft Academic Search

The compatibility of zirconium diboride, boron carbide, and boron ; nitride with type 304 stainless steel was evaluated as a function of temperature ; (1000 to 12OO deg C), time (1-3 hr). Appropriate loadings of the boron compounds ; and stainless steel powder were blended and fashioned into a compact powder ; metallurgically. Each compact was roll clad into a

J. H. Cherubini; C. F. Jr. Leitten

1959-01-01

363

Initial boronization of PBX-M using ablation of solid boronized probes  

SciTech Connect

The initial boronization of PBX-M was performed using the sequential ablation of two types of solid target probes. Probe-1 in a mushroom shape consisted of a 10.7% boronized 2-D C-C composite containing 3.6 g of boron in a B[sub 4]C binder. Probe-2 in a rectangular shape consisted of an 86% boronized graphite felt composite containing 19.5 g of 40 [mu] boron particles. After boronization with Probe-1, the loop voltage during 1 MW neutral beam heated plasmas decreased 27% and volt-sec consumption decreased 20%. Strong peripheral spectral lines from low-Z elements decreased by factors of about 5. The central oxygen density decreased 15--20%. The total radiated power during neutral beam injection decreased by 43%. Probe-2 boronization exhibited improved operating conditions similar to Probe-1, but for some parameters, a smaller percentage change occurred due to the residual boron from the previous boronization using Probe-1. The ablation rates of both probes were consistent with front face temperatures at or slightly above the boron melting point. These results confirm the effectiveness of the solid target boronization (STB) technique as a real-time impurity control method for replenishing boron depositions without the use of hazardous borane compounds.

Kugel, H.W.; Hirooka, Y.; Kaita, R.; Kaye, S.; Khandagle, M. (California Univ., Los Angeles, CA (United States). Inst. of Plasma and Fusion Research); Timberlake, J.; Bell, R.; England, A.; Isler, R.; Okabayashi, M.; Paul, S.; Takahashi, H.; Tighe, W.; von Goeler, S.; Post-Zwicker, A.P. (Oak Ridge National Lab., TN (United States)); Jones, S. (Massachusetts Inst. of Tech., Cambridge, MA (United States))

1993-05-01

364

Effect of Boron on the Incorporation of Glucose from UDP-Glucose into Cotton Fibers Grown in Vitro  

PubMed Central

Boron is required for fiber growth and development in cotton ovules cultured in vitro. Incorporation of [14C]glucose by such fiber from supplied UDP-[14C]glucose into the hot alkali-insoluble fraction is rapid and linear for about 30 minutes. Incorporation of [14C]glucose from such substrate by fibers grown in boron-deficient ovule cultures is much less than in the case with fibers from ovules cultured with boron in the medium. Total products (alkali-soluble plus alkali-insoluble fractions) were also greater in fibers from ovules cultured with boron. The fraction insoluble in acetic-nitric reagent was a small part of the total glucans; however, in the boron-sufficient fibers, there was significantly more of this fraction than in fibers from boron-deficient ovule cultures. The hot water-soluble glucose polymers from the labeled fibers had a significant fraction of the total [14C]glucose incorporated from UDP-[14C]glucose. Both ?-1,4- and ?-1,3- water-soluble polymers were formed in the boron-sufficient fibers, whereas the same water-soluble fraction from the boron-deficient fibers was predominantly ?-1,3-polymers. The incorporation of [14C]glucose from GDP-[14C]glucose by the fibers attached to the ovules was insignificant.

Dugger, W. M.; Palmer, R. L.

1980-01-01

365

Toxic effects of boron on mallard reproduction  

USGS Publications Warehouse

Boron, a naturally occurring trace element generally considered environmentally innocuous, was documented to severely impair mallard reproduction. Boron is leached from irrigated agricultural soils and transported in drainage water that contaminates wetlands. Until now, only the selenium accumulated in aquatic food chains has been documented to pose a toxic hazard to wildlife in drainage water wetlands. Management of drainage water-contaminated environments must now also consider the adverse effects of boron, as well as the possible interactions of drainage water contaminants.

Smith, G.J.; Anders, V.P.

1989-01-01

366

Boron removal in RO seawater desalination  

Microsoft Academic Search

In the seawater desalination field, the WHO requires that boron concentration in drinking water be below 0.5 mg\\/l, and this requirement has affected SWRO process design because of the difficulty in achieving such a low boron concentration. In order to overcome this problem, anew SWRO membrane element with higher boron-rejecting performance was developed. This new SWRO membrane element exhibits excellent

Masahide Taniguchi; Yoshinari Fusaoka; Tsuyoshi Nishikawa; Masaru Kurihara

2004-01-01

367

Dietary boron, brain function, and cognitive performance.  

PubMed Central

Although the trace element boron has yet to be recognized as an essential nutrient for humans, recent data from animal and human studies suggest that boron may be important for mineral metabolism and membrane function. To investigate further the functional role of boron, brain electrophysiology and cognitive performance were assessed in response to dietary manipulation of boron (approximately 0.25 versus approximately 3.25 mg boron/2000 kcal/day) in three studies with healthy older men and women. Within-subject designs were used to assess functional responses in all studies. Spectral analysis of electroencephalographic data showed effects of dietary boron in two of the three studies. When the low boron intake was compared to the high intake, there was a significant (p < 0.05) increase in the proportion of low-frequency activity, and a decrease in the proportion of higher-frequency activity, an effect often observed in response to general malnutrition and heavy metal toxicity. Performance (e.g., response time) on various cognitive and psychomotor tasks also showed an effect of dietary boron. When contrasted with the high boron intake, low dietary boron resulted in significantly poorer performance (p < 0.05) on tasks emphasizing manual dexterity (studies II and III); eye-hand coordination (study II); attention (all studies); perception (study III); encoding and short-term memory (all studies); and long-term memory (study I). Collectively, the data from these three studies indicate that boron may play a role in human brain function and cognitive performance, and provide additional evidence that boron is an essential nutrient for humans.

Penland, J G

1994-01-01

368

Carbon Nitride and Boron Carbon Nitride Nanostructures  

Microsoft Academic Search

This chapter is devoted to carbon nitride and boron carbon nitride nanostructures, an important and indispensable member in\\u000a the family of nanomaterials for various applications, especially in nanoelectronics. It covers all the main aspects of the\\u000a current research on the carbon nitride and boron carbonitride nanostructures. The attention is mainly focused on the one-dimensional\\u000a carbon nitride and boron carbon nitride

Jie Yu; E. G. Wang

369

Role of overexpressed BOR4, a boron exporter, in tolerance to high level of boron in shoots  

Microsoft Academic Search

High boron (B) tolerance is an important trait for crop production in high-B soils. We previously reported that overexpression of BOR4, an Arabidopsis thaliana B exporter, conferred high B tolerance in A. thaliana. This improvement appeared to be mainly due to the decreased B concentrations in roots through BOR4-mediated exclusion of B. In the present study, we describe a novel

Kyoko Miwa; Toru Fujiwara

2011-01-01

370

Synthesis of alpha- and beta-Rhombohedral Boron Powders via Gas Phase Thermal Dissociation of Boron Trichloride by Hydrogen  

Microsoft Academic Search

The alpha-rhombohedral and beta-rhombohedral crystal structures of pure elemental boron powders have been synthesized via gas phase thermal dissociation of BCl3 by H2 on a quartz substrate. The parameters affecting the crystal structures of the final products and the process efficiency, such as BCl3\\/H2 molar ratio (1\\/2 and 1\\/4) and reaction temperature (1173 K to 1373 K [900 °C to

Duygu Agaogullari; Özge Balci; Ismail Duman; M. Lütfi Öveçoglu

2011-01-01

371

Explorations of mechanisms regulating ectomycorrhizal colonization of boron-fertilized pine: Quarterly report, October 1-December 31, 1987  

SciTech Connect

The studies explore two related hypotheses. The potential of boron and indole acetic acid to act synergistically to promote the flow of sucrose from the foliage to the roots is being assessed. Further the ability of boron fertilization to disrupt the production of phenols by the host is determined. Since phenols inhibit mycorrhizal colonization, it is reasoned that inhibition of phenol production should facilitate plant growth. (DT)

Garrett, H.E.; Reid, R.K.; Sword, M.A.

1987-01-01

372

Low temperature boron doped diamond  

NASA Astrophysics Data System (ADS)

Low temperature boron doped diamond (LT-BDD) film deposited under 600 °C (460 °C minimum) has been reported. Study reveals that the deposition temperature and boron dopant cause nanocrystalline diamond (NCD) instead of ultrananocrystalline diamond (UNCD®). Unlike conventional NCD, LT-BDD has faster renucleation rate, which ensures a low surface roughness (approximately 10 nm at 0.6 ?m thickness). The overall characteristics of LT-BDD are mixed with the characteristics of conventional NCD and UNCD. Raman spectrum and electrochemical characterization prove that the quality of LT-BDD is similar to those grown under 650-900 °C. LT-BDD enables diamond applications on microelectromechanical systems, bio- and optical technologies.

Zeng, Hongjun; Arumugam, Prabhu U.; Siddiqui, Shabnam; Carlisle, John A.

2013-06-01

373

CVD-produced boron filaments  

SciTech Connect

A technique for producing boron filaments with an average tensile strength of 6.89 GPa has been developed which involves longitudinal splitting of the filament and core (substrate) removal by etching. Splitting is accomplished by a pinch wheel device which continuously splits filaments in lengths of 3.0 m by applying a force to the side of the filament to create a crack which is then propagated along the axis by a gentle sliding action. To facilitate the splitting, a single 10 mil tungsten substrate is used instead of the usual 0.5 mil substrate. A solution of hot 30% hydrogen peroxide is used to remove the core without attacking the boron. An alternative technique is to alter the residual stress by heavily etching the filament. Average strengths in the 4.83-5.52 GPa range have been obtained by etching an 8 mil filament to 4 mil.

Wawner, F.E. (Virginia, University, Charlottesville, Va.); Debolt, H.E. (Avco Corp., Avco Specialty Materials Div., Lowell, Mass.)

1980-07-01

374

METHOD OF PREPARING POLONIUM-BORON SOURCES  

DOEpatents

An improved technique is described for preparation of a polonium-boron neutron source. A selected amount of Po-210 is vaporized into a thin walled nickel container, then the desired amcunt of boron powder is added. After sealing the container, it is heated quickly by induction heating to vaporize the Po-210 and deposit it in the still cool boron powder. The unit is then quickly cooled to prevent revaporization of the Po-210 from the boron. The build-up of neutron emission may be followed by means of a neutron counter in order to terminate the heating at the optimum level of neutron yield.

Birden, J.H.

1959-08-01

375

Self-doping in Boron Nanostructures  

NASA Astrophysics Data System (ADS)

Boron nanotubes have attracted much attention since their first fabrication in experiments. Boron nanotubes with large radii (R >= 10 å) are predicted to be metallic with large densities of states at their Fermi energies, which may provide excellent conducting systems for one-dimensional electronics. In previous work [1], we have shown a class of stable boron sheets, composed of mixtures of triangular and hexagonal motifs, that are likely to be the precursors of boron nanotubes. These sheets are stabilized by a balance of 2-center and 3-center bonding. Here, using density functional theory and Maximally Localized Wannier Functions, we show that adding a boron atom to a boron sheet is equivalent to doping the boron sheet with all three valence electrons of the added atom. Based on this self-doping picture, we propose a simple counting scheme to construct stable boron nanostructures, e.g. from corresponding carbon ones. We also apply this knowledge to study Mg-doped boron sheets and discuss the possible stable structures of MgB2 nanotubes. [1] H. Tang, and S. Ismail-Beigi, Phys. Rev. Lett. 99, 115501 (2007).

Tang, Hui; Ismail-Beigi, Sohrab

2009-03-01

376

Hafnium radioisotope recovery from irradiated tantalum  

DOEpatents

Hafnium is recovered from irradiated tantalum by: (a) contacting the irradiated tantalum with at least one acid to obtain a solution of dissolved tantalum; (b) combining an aqueous solution of a calcium compound with the solution of dissolved tantalum to obtain a third combined solution; (c) precipitating hafnium, lanthanide, and insoluble calcium complexes from the third combined solution to obtain a first precipitate; (d) contacting the first precipitate of hafnium, lanthanide and calcium complexes with at least one fluoride ion complexing agent to form a fourth solution; (e) selectively adsorbing lanthanides and calcium from the fourth solution by cationic exchange; (f) separating fluoride ion complexing agent product from hafnium in the fourth solution by adding an aqueous solution of ferric chloride to obtain a second precipitate containing the hafnium and iron; (g) dissolving the second precipitate containing the hafnium and iron in acid to obtain an acid solution of hafnium and iron; (h) selectively adsorbing the iron from the acid solution of hafnium and iron by anionic exchange; (i) drying the ion exchanged hafnium solution to obtain hafnium isotopes. Additionally, if needed to remove residue remaining after the product is dried, dissolution in acid followed by cation exchange, then anion exchange, is performed.

Taylor, Wayne A. (Los Alamos, NM); Jamriska, David J. (Los Alamos, NM)

2001-01-01

377

Glioblastoma: Boron Neutron Capture Therapy  

Microsoft Academic Search

\\u000a Boron neutron capture therapy (BNCT) is a unique method that can deliver tumor-cell-selective high-linear energy transfer\\u000a (LET) particle radiotherapy to an extended target area encompassing a microscopic invasion while avoiding radiation damage\\u000a to the surrounding normal brain tissue. The process of BNCT is based on the nuclear interaction of 10B with thermal neutrons with the release of high LET ?

Tetsuya Yamamoto; Kei Nakai; Hiroaki Kumada

378

Modeling Boron Adsorption on Kaolinite  

Microsoft Academic Search

Boron adsorption at constant ionic strength (0.09 _+ 0.01 moles\\/liter of KC10, or Ca(C104)2) on 0.2-2 #m clay fraction of pretreated kaolinite was modeled using both phenomenological equations and surface complexation reactions. Phenomenological equations were expressed as linear relationships between the distribution coefficient and adsorption density or equilibrium concentration. The normalized form of the isotherms allowed the distribution coefficient to

Shivi P. N. Singh

1992-01-01

379

Radioisotope electric propulsion of sciencecraft to the outer solar system and near-interstellar space  

Microsoft Academic Search

Recent results are presented in the study of radioisotope electric propulsion as a near-term technology for sending small robotic sciencecraft to the outer Solar System and near-interstellar space. Radioisotope electric propulsion (REP) systems are low-thrust, ion propulsion units based on radioisotope electric generators and ion thrusters. Powerplant specific masses are expected to be in the range of 100 to 200

1998-01-01

380

Radioisotopes for heat-source applications  

SciTech Connect

Potential DOD requirements for noninterruptable power sources could total 1 MW thermal by FY 1990. Of the three isotopes considered, (/sup 90/Sr, /sup 147/Pm, /sup 238/Pu) /sup 90/Sr is the only one available in sufficient amounts to meet this requirement. To meet the DOD FY 1990 requirements, it would be necessary to undertake /sup 90/Sr recovery operations from spent fuel reprocessing at SRP, Hanford, and the Barnwell Nuclear Fuels Plant (BNFP). /sup 90/Sr recovery from the existing alkaline high level waste (HLW) at Hanford and SRP is not attractive because the isotopic purity of the /sup 90/Sr is below that required for DOD applications. Without reprocessing LWR spent fuel, SRP and Hanford could not supply the demand of 1 MW thermal until FY 1996. Between FY 1983 and FY 1996, SRP and Hanford could supply approximately 0.70 MW of /sup 90/Sr and 0.15 MW of /sup 147/Pm. SRP could supply an additional 0.15 MW from the production and recovery of /sup 238/Pu. Strontium-90 is the most economical of the three heat source radionuclides considered. The /sup 90/Sr unit recovery cost from SRP fresh acid waste would be $180/watt. The BNFP /sup 90/Sr recovery cost would be $130/watt to $235/watt depending on the age and burnup of the LWR spent fuel. Hanford /sup 90/Sr recovery costs form Purex fresh acid waste are unavailable, but they are expected to be comparable to the SRP costs. /sup 147/Pm and /sup 238/Pu are considerably more expensive heat source materials. /sup 147/Pm recovery costs at SRP are estimated to be $450/watt. As with /sup 90/Sr, the Hanford /sup 147/Pm recovery costs are expected to be comparabl to the SRP costs. Production of high assay (93.5%) /sup 238/Pu at SRP from excess /sup 231/Np would cost about $1160/watt, while recovery of low assay (27%) /sup 238/Pu from the waste stream is estimated at $1850/watt.

Hoisington, J.E.

1982-10-06

381

Ferrocenyl-substituted Schiff base complexes of boron: synthesis, structural, physico-chemical and biochemical aspects.  

PubMed

Biological important complexes of boron(III) derived from 1-acetylferrocenehydrazinecarboxamide (L1H), 1-acetylferrocenehydrazinecarbothioamide (L2H) and 1-acetylferrocene carbodithioic acid (L3H) have been prepared and investigated using a combination of microanalytical analysis, melting point, electronic, IR, 1H NMR and 13C NMR spectral studies, cyclic voltammetry and X-ray powder diffraction studies. Boron isopropoxide interacts with the ligands in 1:1, 1:2 and 1:3 molar ratios (boron:ligand) resulting in the formation of coloured products. On the basis of conductance and spectral evidences, tetrahedral structures for boron(III) complexes have been assigned. The ligands are coordinated to the boron(III) via the azomethine nitrogen atom and the thiolic sulfur atom/enolic oxygen atom. On the basis of X-ray powder diffraction study one of the representative boron complex was found to have orthorhombic lattice, having lattice parameters: a=9.9700, b=15.0000 and c=7.0000. Both the ligands and their complexes have been screened for their biological activity on several pathogenic fungi and bacteria and were found to possess appreciable fungicidal and bactericidal properties. Plant growth regulating activity of one of the ligand and its complexes has also been recorded on gram plant, and results have been discussed. PMID:21167770

Yadav, Sunita; Singh, R V

2010-12-16

382

Beryllium and boron in metal-poor stars  

NASA Astrophysics Data System (ADS)

Knowledge of lithium, beryllium, and boron abundances in stars of the Galactic halo and disk plays a major role in our understanding of Big Bang nucleosynthesis, cosmic-ray physics, and stellar interiors. 9Be and 10B are believed to originate entirely from spallation reactions in the interstellar medium (ISM) between ?-particles and protons and heavy nuclei like carbon, nitrogen, and oxygen (CNO), whereas 11B may have an extra production channel via neutrino-spallation. Beryllium and boron are both observationally challenging, with their main resonant doublets falling respectively at 313 nm and at 250 nm. The advent of 8-10m class telescopes equipped with highly sensitive (in the near-UV/blue) spectrographs has opened up a new era of Be abundance studies. Here, I will review and discuss the most interesting results of recent observational campaigns in terms of formation and evolution of these two light elements.

Primas, Francesca

2010-04-01

383

A compendium of the radioisotope thermoelectric generator transportation system and recent programmatic changes  

SciTech Connect

Because RTGs contain significant quantities of radioactive materials, usually plutonium-238 and its decay products, they must be transported in packages built in accordance with 10 CFR 71 (1994). To meet these regulatory requirements, US DOE commissioned Westinghouse Hanford Co. in 1988 to develop a Radioisotope Thermoelectric Generator Transportation System (RTGTS) that would fully comply while protecting RTGs from adverse environmental conditions during normal transport conditions (eg, mainly shock and heat). RTGTS is scheduled for completion Dec. 1996 and will be available to support NASA`s Cassini mission to Saturn in Oct. 1997. This paper provides an overview of the RTGTS project, discusses the hardware being produced, and summarizes various programmatic and management innovations required by recent changes at DOE.

Becker, D.L.; McCoy, J.C.

1996-03-01

384

Thermal Conductivity Behavior of Boron Carbides.  

National Technical Information Service (NTIS)

Knowledge of the thermal conductivity of boron carbides is necessary to evaluate its potential for high temperature thermoelectric energy conversion applications. The thermal diffusivity of hot pressed boron carbide B/sub 1-x/C/sub x/ samples as a functio...

C. Wood A. Zoltan D. Emin P. E. Gray

1983-01-01

385

Thermal Conductivity Behavior of Boron Carbides.  

National Technical Information Service (NTIS)

Knowledge of the thermal conductivity of boron carbides is necessary to evaluate its potential for high temperature thermoelectric energy conversion applications. We have measured the thermal diffusivity of hot-pressed boron carbide B/sub 1-x/C/sub x/ sam...

C. Wood A. Zoltan D. Emin P. E. Gray

1983-01-01

386

Thermionic Properties of the Molybdenum Boron System.  

National Technical Information Service (NTIS)

The thermionic work function has been measured as a function of composition within the various two phase regions between Mo and MoB sub 2 . Values at the low boron and high boron phase boundaries for the various compounds were obtained by extrapolation. T...

E. K. Storms

1980-01-01

387

Electronic Structure of Hexagonal Boron Nitride.  

National Technical Information Service (NTIS)

The anisotropic emission of the K x-radiation of boron and nitrogen in hexagonal boron nitride BN permits the determination of the pi - and sigma-subbands of the two X-ray spectra. Together with the X-ray photoelectron spectrum a consistent picture of the...

E. Tegeler N. Kosuch G. Wiech A. Faessler

1978-01-01

388

Boron chemicals in diagnosis and therapeutics.  

PubMed

Advances in the field of boron chemistry have expanded the application of boron from material use to medicine. Boron-based drugs represent a new class of molecules that possess several biomedical applications including use as imaging agents for both optical and nuclear imaging as well as therapeutic agents with anticancer, antiviral, antibacterial, antifungal and other disease-specific activities. For example, bortezomib (Velcade(®)), the only drug in clinical use with boron as an active element, was approved in 2003 as a proteasome inhibitor for the treatment of multiple myeloma and non-Hodgkin's lymphoma. Several other boron-based compounds are in various phases of clinical trials, which illustrates the promise of this approach for medicinal chemists working in the area of boron chemistry. It is expected that in the near future, several boron-containing drugs should become available in the market with better efficacy and potency than existing drugs. This article discusses the current status of the development of boron-based compounds as diagnostic and therapeutic agents in humans. PMID:23617429

Das, Bhaskar C; Thapa, Pritam; Karki, Radha; Schinke, Caroline; Das, Sasmita; Kambhampati, Suman; Banerjee, Sushanta K; Van Veldhuizen, Peter; Verma, Amit; Weiss, Louis M; Evans, Todd

2013-04-01

389

Fabrication of boron-phosphide neutron detectors  

SciTech Connect

Boron phosphide is a potentially viable candidate for high neutron flux neutron detectors. The authors have explored chemical vapor deposition methods to produce such detectors and have not been able to produce good boron phosphide coatings on silicon carbide substrates. However, semi-conducting quality films have been produced. Further testing is required.

Fitzsimmons, M.; Pynn, R.

1997-07-01

390

Method of Extracting Boron from Natural Brines.  

National Technical Information Service (NTIS)

The object of the invention is a method of extracting boron from natural brines. For a more thorough extraction of boron, the brine is treated with a mixture of lime with aluminum sulfates, or with salt of trivalent iron (for example, chloride, or sulfate...

K. I. Khrennikov

1965-01-01

391

Method of Preparing Nonlaminating Anisotropic Boron Nitride.  

National Technical Information Service (NTIS)

The general object of this invention is to provide a method of preparing non laminating anisotropic boron nitride. A further object is to provide such a method wherein the resulting non laminated anisotropic boron nitride will form a strong bond and hold ...

L. E. Branovich B. Smith G. L. Freeman

1985-01-01

392

Porphyrins for boron neutron capture therapy  

DOEpatents

Novel compounds for treatment of brain tumors in Boron Neutron Capture Therapy are disclosed. A method for preparing the compounds as well as pharmaceutical compositions containing said compounds are also disclosed. The compounds are water soluble, non-toxic and non-labile boronated porphyrins which show significant uptake and retention in tumors.

Miura, Michiko (Center Moriches, NY); Gabel, Detlef (Bremen, DE)

1990-01-01

393

Boron Carbide Continuous Filaments. Part II.  

National Technical Information Service (NTIS)

The purpose of this program was to develop and evaluate a process for producing continuous lengths of boron carbide filament having tensile strengths approaching 500,000 psi and elastic moduli close to that of bulk boron carbide (60-70 million psi) are be...

J. B. Higgins J. J. Gebhart A. Gatti J. M. Berry W. E. Saver

1966-01-01

394

Substrate metabolism in isolated rat jejunal epithelium. Analysis using /sup 14/C-radioisotopes  

SciTech Connect

The jejunal epithelium absorbs nutrients from the intestinal lumen and is therefore the initial site for metabolism of these compounds. The purpose of this investigation is to analyze substrate metabolism in a preparation of jejunal epithelium relatively free of other tissues. Novel radioisotopic labelling techniques allow quantitation of substrate metabolism in the TCA cycle, Embden-Meyerhof (glycolytic) pathway, and hexose monophosphate shunt. For example, ratios of /sup 14/CO/sub 2/ production from pairs of /sup 14/C-pyruvate, and /sup 14/C-succinate radioisotopes (CO/sub 2/ ratios) indicate the probability of TCA cycle intermediate efflux to generate compounds other than CO/sub 2/. With (2,3-/sup 14/C)succinate as tracer, the ratio of /sup 14/C in carbon 4 + 5 versus carbon 2 + 3 of citrate, the citrate labelling ratio, equals the probability of TCA intermediate flux to the acetyl CoA-derived portion of citrate versus flux to the oxaloacetate-derived portion. The principal metabolic substrates for the jejunal epithelium are glucose and glutamine. CO/sub 2/ ratios indicate that glutamine uptake and metabolism is partially Na/sup +/-independent, and is saturable, with a half-maximal rate at physiological plasma glutamine concentrations. Glucose metabolism in the jejunal epithelium proceeds almost entirely via the Embden-Meyerhof pathway. Conversion of substrates to multi-carbon products in this tissue allows partial conservation of reduced carbon for further utilization in other tissues. In summary, metabolic modeling based on /sup 14/C labelling ratios is a potentially valuable technique for analysis of metabolic flux patterns in cell preparations.

Mallet, R.T.

1986-01-01

395

Development of Advanced Stirling Radioisotope Generator for Space Exploration  

NASA Astrophysics Data System (ADS)

Under the joint sponsorship of the Department of Energy and NASA, a radioisotope power system utilizing Stirling power conversion technology is being developed for potential future space missions. The higher conversion efficiency of the Stirling cycle compared with that of Radioisotope Thermoelectric Generators (RTGs) used in previous missions (Viking, Pioneer, Voyager, Galileo, Ulysses, Cassini, and New Horizons) offers the advantage of a four-fold reduction in PuO2 fuel, thereby saving cost and reducing radiation exposure to support personnel. With the advancement of state-of-the-art Stirling technology development under the NASA Research Announcement (NRA) project, the Stirling Radioisotope Generator program has evolved to incorporate the advanced Stirling convertor (ASC), provided by Sunpower, into an engineering unit. Due to the reduced envelope and lighter mass of the ASC compared to the previous Stirling convertor, the specific power of the flight generator is projected to increase from 3.5 We/kg to 7 We/kg, along with a 25% reduction in generator length. Modifications are being made to the ASC design to incorporate features for thermal, mechanical, and electrical integration with the engineering unit. These include the heat collector for hot end interface, cold-side flange for waste heat removal and structural attachment, and piston position sensor for ASC control and power factor correction. A single-fault tolerant, active power factor correction controller is used to synchronize the Stirling convertors, condition the electrical power from AC to DC, and to control the ASCs to maintain operation within temperature and piston stroke limits. Development activities at Sunpower and NASA Glenn Research Center (GRC) are also being conducted on the ASC to demonstrate the capability for long life, high reliability, and flight qualification needed for use in future missions.

Chan, Jack; Wood, J. Gary; Schreiber, Jeffrey G.

2007-01-01

396

Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission  

NASA Astrophysics Data System (ADS)

The preceding paper (Schock 1994) described conceptual designs and analytical results for five Radioisotope Thermoelectric Generator (RTG) options for the Pluto Fast Flyby (PFF) mission, and the present paper describes three Radioisotope Stirling Generator (RSG) options for the same mission. The RSG options are based on essentially the same radioisotope heat source modules used in previously flown RTGs and on designs and analyses of a 75-Watt free-piston Stirling engine produced by Mechanical Technology Incorporated (MTI) for NASA's Lewis Research Center. The integrated system design options presented were generated in a Fairchild Space study sponsored by the Department of Energy's Office of Special Applications, in support of ongoing PFF mission and spacecraft studies that the Jet Propulsion Laboratory (JPL) is conducting for the National Aeronautics and Space Administration (NASA). That study's NASA-directed goal is to reduce the spacecraft mass from its baseline value of 166 kg to -110 kg, which implies a mass goal of less than 10 kg for a power source able to deliver 69 Watts(e) at the end of the 9.2-year mission. In general, the Stirling options were found to be lighter than the thermoelectric options described in the preceding paper. But they are less mature, requiring more development, and entailing greater programmatic risk. The Stirling power system mass ranged from 7.3 kg (well below the 10-kg goal) for a non-redundant system to 11.3 kg for a redundant system able to maintain full power if one of its two engines fails. In fact, the latter system could deliver as much as 115 Watts(e) if desired by the mission planners.

Schock, Alfred

1994-07-01

397

Boronic acid building blocks: tools for sensing and separation  

Microsoft Academic Search

In this feature article the use of boronic acids to monitor, identify and isolate analytes within physiological, environmental and industrial scenarios is discussed. Boronic acids recognise diol motifs through boronic ester formation and interact with anions generating boronates, as such they have been exploited in sensing and separation protocols for diol appended molecules such as saccharides and anions alike. Therefore

T. D. James; R. Nishiyabu; Y. Kubo; J. S. Fossey

2011-01-01

398

Superplastic boronizing of duplex stainless steel under dual compression method  

Microsoft Academic Search

In this work, SPB of duplex stainless steel (DSS) under compression method is studied with the objective to produce ultra hard and thick boronized layer using minimal amount of boron powder and at a much faster boronizing time as compared to the conventional process. SPB is conducted under dual compression methods. In the first method DSS is boronized using a

I. Jauhari; H. A. M. Yusof; R. Saidan

2011-01-01

399

Boronic acid functionalized polymers and hydrogels for biomedical applications  

Microsoft Academic Search

Boronic acid functionalized polymers are a very interesting class of materials capable of forming reversible covalent boronic esters. With boronic acids reversible binding of diols and polyols, including carbohydrates, is possible. Although such polymers are promising biomaterials, they are only rarely explored. Thus the goal of this research was to investigate the potential of boronic acid functionalized polymers for biomedical

Martin Piest

2011-01-01

400

Hydrocarbon analogues of boron clusters - planarity, aromaticity and antiaromaticity  

Microsoft Academic Search

An interesting feature of elemental boron and boron compounds is the occurrence of highly symmetric icosahedral clusters. The rich chemistry of boron is also dominated by three-dimensional cage structures. Despite its proximity to carbon in the periodic table, elemental boron clusters have been scarcely studied experimentally and their structures and chemical bonding have not been fully elucidated. Here we report

Hua-Jin Zhai; Boggavarapu Kiran; Jun Li; Lai-Sheng Wang

2003-01-01

401

The chemical vapor deposition of boron at low temperatures  

Microsoft Academic Search

The formation of boron coatings obtained from the dissociation of diborane as a function of temperature, pressure and the effect of plasma activities is investigated. At one atm. pressure, pure boron was formed only at deposition temperatures above 500°C; below that temperature partial dissociation occurred and the deposited boron was combined with boron polymers. To remove these polymers (as they

H. O. Pierson; A. W. Mullendore

1981-01-01

402

Boron removal from saline water: A comprehensive review  

Microsoft Academic Search

Boron is an essential micronutrient for plants and animals as well as a useful component for numerous industries. It is necessary to produce low boron containing water from RO desalination plants for both human consumption and for agriculture. For plants, a small amount of boron is necessary for their growth and development, but boron becomes toxic if the amount is

N. Hilal; G. J. Kim; C. Somerfield

2011-01-01

403

Recombination Activity of Iron in Boron Doped Silicon  

NASA Astrophysics Data System (ADS)

The charge carrier lifetime in iron contaminated boron doped silicon wafers was determined by surface photovoltage, SPV, and microwave photoconductive decay, µPCD, techniques. Our results show that the charge carrier lifetime in boron doped silicon wafers depends on the boron concentration when the lifetime is limited by iron-boron pairs.

Yli-Koski, M.; Palokangas, M.; Sokolov, V.; Storgårds, J.; Väinölä, H.; Holmberg, H.; Sinkkonen, J.

404

Rhenium-188--a generator-derived radioisotope for cancer therapy.  

PubMed

Rhenium-188 (188Re) is an important therapeutic radioisotope which is obtained on demand as carrier-free sodium perrhenate by saline elution of the tungsten-188/rhenium-188 generator system. With a half-life of 16.9 hours and emission of a high energy beta particle (maximal energy of 2.12 MeV) and a gamma photon (155 keV, 15%) for imaging, 188Re can be provided at reasonable costs for routine preparation of radiopharmaceuticals for cancer treatment. PMID:10851424

Knapp, F F

1998-10-01

405

Radioisotope measurement of the velocity of tracheal mucus  

SciTech Connect

A radioisotope scanning technique for measuring the velocity of tracheal mucus has been developed utilizing a canine model. A solution of stannous phytate labeled with /sup 99m/Tc is introduced percutaneously into the lower trachea and the upward movement of the leading edge of the radioactivity is followed by repeat scanning at 2-minute intervals using a modified rectilinear scanner, thus allowing calculation of the velocity of the mucus. It is believed that this technique may be of value in studying the effect of experimentally induced tracheal injuries on mucus velocity. Possible applications of the technique for the study of the velocity of mucus in the human trachea are discussed.

Russo, K.J.; Palmer, D.W.; Beste, D.J.; Carl, G.A.; Belson, T.P.; Pelc, L.R.; Toohill, R.J.

1985-04-01

406

Mechanism of boron-induced embrittlement of Ni{sub 3}Al in hydrogen  

SciTech Connect

Materials that have been exposed to H{sub 2} or hydrogen-containing gases often show embrittlement due to atomic hydrogen. It is now recognized that hydrogen embrittlement is the source of brittle behavior of a number of intermetallics that were previously thought to be intrinsically brittle. A well-known example is polycrystalline Ni{sub 3}Al, which is susceptible to environmental embrittlement in atmospheres containing water vapor, and the mechanism of H production is the dissociation of H{sub 2}O at active Al sites. Further investigations to identify how B additions affect the fracture susceptibility of Ni{sub 3}Al in H{sub 2} atmospheres discovered a surprising phenomenon: boron-induced embrittlement. Insufficient data are available to build more than a speculative atomic-level model to explain this counterintuitive connection of boron with embrittlement. One explanation has been proposed in terms of the chemical participation of boron in the H{sub 2} dissociation step. However, the chemistry of boron does not support a direct dissociation step. And simple electronic structure considerations discussed later suggest boron would not act as a promoter in an indirect dissociation of H{sub 2}. The alternate mechanism proposed here, although tentative until further evidence is attained, is based on well-established atomic-level properties of boron in Ni{sub 3}Al. In the following, the concept of the activity of interfaces with regard to H{sub 2} molecular dissociation in the region of intersection of the grain boundary with the gas/solid interface is used to explain how boron can affect atomic hydrogen production. Activity will refer exclusively to the H{sub 2} molecular dissociation reaction unless noted otherwise.

Painter, G.S. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1997-10-01

407

Experimental boron neutron capture therapy for melanoma: Systemic delivery of boron to melanotic and amelanotic melanoma  

SciTech Connect

The boron-containing melanin precursor analogue p-boronophenylalanine (BPA) has previously been shown to selectively deliver boron to pigmented murine melanomas when administered in a single intragastric dose. If boron neutron capture therapy is to become a clinically useful method of radiation therapy for human malignant melanoma, the boron carrier must be capable of delivering useful amounts of boron to remote tumor sites (metastases) and to poorly pigmented melanomas. The authors have now determined the ability of BPA to accumulate in several nonpigmented melanoma models including human melanoma xenografts in nude mice. The absolute amount of boron in the nonpigmented melanomas was about 50% of the observed in the pigmented counterparts but was still selectively concentrated in the tumor relative to normal tissues in amounts sufficient for effective neutron capture therapy. Single intragastric doses of BPA resulted in selective localization of boron in the amelanotic Greene melanoma carried in the anterior chamber of the rabbit eye and in a pigmented murine melanoma growing in the lungs. The ratio of the boron concentration in these tumors to the boron concentration in the immediately adjacent normal tissue was in the range of 3:1 to 4:1. These distribution studies support the proposal that boron neutron capture therapy may be useful as a regional therapy for malignant melanoma.

Coderre, J.A.; Glass, J.D.; Micca, P.; Greenberg, D. (Brookhaven National Lab., Upton, NY (United States)); Packer, S. (Brookhaven National Lab., Upton, NY (United States) North Shore University Hospital Manhasset, NY (United States))

1990-01-01

408

Radioisotope X-ray fluorescence and neutron activation analyses of the trace element concentrations of the rainbow trout  

NASA Astrophysics Data System (ADS)

The muscles and livers of the ten rainbow trouts ( Oncorhynchus mykiss; N, 1752) obtained from Sapanca, Aquaculture Facility of Aquatic Products Faculty, The University of Istanbul (Turkey), have been analysed quantitatively for some minor elements using the radioisotope energy dispersive X-ray fluorescence (EDXRF) and neutron activation analysis (NAA) methods. It was found that samples contain Na, K, Ca, Sc, Cs, Fe, Co, Cu, Zn, Se, Br, Rb, Sr, Au, La and Ce in different amounts. Comparison of the results with those of reference river fish samples indicated that agricultural rainbow trout samples from Sapanca region have higher Fe level.

Akyuz, T.; Bassari, A.; Bolcal, C.; Sener, E.; Yildiz, M.; Kucer, R.; Kaplan, Z.; Dogan, G.; Akyuz, S.

1999-01-01

409

Boron Enrichment in Martian Clay  

PubMed Central

We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

Nagashima, Kazuhide; Freeland, Stephen J.

2013-01-01

410

Boron enrichment in martian clay.  

PubMed

We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

2013-06-06

411

Hydrocarbon Analogues of Boron Clusters: Planarity, Aromaticity, and Antiaromaticity  

SciTech Connect

An interesting feature of elemental boron and boron compounds is the occurrence of highly symmetric icosahedral clusters. The rich chemistry of boron is also dominated by three-dimensional cage structures. Despite its proximity to carbon, elemental boron clusters have been scarcely studied experimentally and their structures and chemical bonding have not been fully elucidated. Here we report experimental and theoretical evidence that small boron clusters prefer planar structures and exhibit aromaticity and antiaromaticity according to the Hckel rules, akin to planar hydrocarbons. Aromatic boron clusters possess more circular shapes whereas antiaromatic boron clusters are elongated, analogous to structural distortions of antiaromatic hydrocarbons. The planar boron clusters are thus the only series of molecules other than the hydrocarbons to exhibit size-dependent aromatic and antiaromatic behavior and represent a new dimension of boron chemistry. The stable aromatic boron clusters may exhibit similar chemistries as that of benzene, such as forming sandwich-type metal compounds.

Zhai, Hua-Jin; Boggavarapu, Kiran; Li, Jun; Wang, Lai-Sheng

2003-12-01

412

TMI-2 Fission Product Inventory Estimates (Draft).  

National Technical Information Service (NTIS)

This report presents the results of analyses performed to estimate the inventory and distribution of selected radioisotopes within the TMI-2 reactor system. The intent of the report is to document the method used in estimating the fission product inventor...

E. L. Tolman M. Nishio

1987-01-01

413

Carborane derivative development for boron neutron capture therapy. Final report  

SciTech Connect

Boron Neutron Capture Therapy [BNCT] is a binary method of cancer therapy based on the capture of neutrons by a boron-10 atom [{sup 10}B]. Cytotoxic {sup 7}Li nuclei and {alpha}-particles are emitted, with a range in tissue of 9 and 5 {micro}m, respectively, about one cell diameter. The major obstacle to clinically viable BNCT is the selective localization of 5-30 ppm {sup 10}B in tumor cells required for effective therapy. A promising approach to BNCT is based on hydrophilic boron-rich oligomeric phosphate diesters, or ''trailers'' that have been shown to concentrate selectively in tumor tissue. Examples of these compounds were prepared previously at high cost using an automated DNA synthesizer. Direct synthesis methods are needed for the production of gram-scale quantities for further biological evaluation. The work accomplished as a result of the collaboration between Fluorochem, Inc. and UCLA demonstrates that short oligomers containing at least five carborane units with four phosphodiester linkages can be prepared in substantial quantities. This work was accomplished by the application of standard phosphoramidite coupling chemistry.

Barnum, Beverly A.; Yan Hao; Moore, Roger; Hawthorne, M. Frederick; Baum, Kurt

1999-04-01

414

Boron Oxide Encapsulated Vertical Bridgman Grown CdZnTe Crystals as X-Ray Detector Material  

Microsoft Academic Search

Two-inch-diameter CdZnTe crystals doped with indium were grown by the boron oxide encapsulated vertical Bridgman technique. The crystals showed large single crystalline yield and low etch pit density. The background impurity content was dominated by boron in concentration lower than 1 ppm. High resistivity was obtained and a procedure for contact preparation was developed. The mobility-lifetime product of the material

Andrea Zappettini; Mingzheng Zha; Laura Marchini; Davide Calestani; Roberto Mosca; Enos Gombia; Lucio Zanotti; Massimiliano Zanichelli; Maura Pavesi; Natalia Auricchio; Ezio Caroli

2009-01-01

415

Use of a Converted Magnetron for Making Electric Generator with Radioisotopes or a Converting Cell of the Fission Nuclear Energy.  

National Technical Information Service (NTIS)

The principle of the electric generator with radioisotopes as well as of the converting cell of the fission nuclear energy using a modified magnetron is explained. Both the electric generator with radioisotopes and the converting cell of the fission nucle...

G. Cristea G. Fratiloiu

1975-01-01

416

Analysis, optimization, and assessment of radioisotope thermophotovoltaic system design for an illustrative space mission  

Microsoft Academic Search

A companion paper presented at this conference described the design of a Radioisotope Thermophotovoltaic (RTPV) Generator for an illustrative space mission (Pluto Fast Flyby). It presented a detailed design of an integrated system consisting of a radioisotope heat source, a thermophotovoltaic converter, and an optimized heat rejection system. The present paper describes the thermal, electrical, and structural analyses which led

A. Schock; M. Mukunda; G. Summers

1995-01-01

417

Analysis, Optimization, and Assessment of Radioisotope Thermophotovoltaic System Design for an Illustrative Space Mission  

Microsoft Academic Search

A companion paper presented at this conference described the design of a Radioisotope Thermophotovoltaic (RTPV) Generator for an illustrative space mission (Pluto Fast Flyby). It presented a detailed design of an integrated system consisting of a radioisotope heat source, a thermophotovoltaic converter, and an optimized heat rejection system. The present paper describes the thermal, electrical, and structural analyses which led

Alfred Schock; Meera Mukunda; G. Summers

1994-01-01

418

Kuiper Belt Object Orbiter Using Advanced Radioisotope Power Sources and Electric Propulsion.  

National Technical Information Service (NTIS)

A joint NASA GRC/JPL design study was performed for the NASA Radioisotope Power Systems Office to explore the use of radioisotope electric propulsion for flagship class missions. The Kuiper Belt Object Orbiter is a flagship class mission concept projected...

A. Colozza J. Dankanich J. Drexler J. Fittje M. L. McGuire O. Khan P. Schmitz S. R. Oleson

2011-01-01

419

Radioisotope electric propulsion of sciencecraft to the outer solar system and near-interstellar space.  

National Technical Information Service (NTIS)

Recent results are presented in the study of radioisotope electric propulsion as a near-term technology for sending small robotic sciencecraft to the outer Solar System and near-interstellar space. Radioisotope electric propulsion (REP) systems are low-th...

R. J. Noble

1998-01-01

420

Radioisotope Electric Propulsion for Deep Space Sample Return  

SciTech Connect

The need to answer basic questions regarding the origin of the Solar System will motivate robotic sample return missions to destinations like Pluto, its satellite Charon, and objects in the Kuiper belt. To keep the mission duration short enough to be of interest, sample return from objects farther out in the Solar System requires increasingly higher return velocities. A sample return mission involves several complicated steps to reach an object and obtain a sample, but only the interplanetary return phase of the mission is addressed in this paper. Radioisotope electric propulsion is explored in this parametric study as a means to propel small, dedicated return vehicles for transferring kilogram-size samples from deep space to Earth. Return times for both Earth orbital rendezvous and faster, direct atmospheric re-entry trajectories are calculated for objects as far away as 100 AU. Chemical retro-rocket braking at Earth is compared to radioisotope electric propulsion but the limited deceleration capability of chemical rockets forces the return trajectories to be much slower.

Noble, Robert J.; /SLAC

2009-07-14

421

[Radioisotope decontamination of X-ray detector (photostimulable phosphor plate)].  

PubMed

We tried to remove contamination of radioisotope (RI) for an X-ray detector (photostimulable phosphor plate; IP) and verified that our procedure suggested by Nishihara et al. was effective for decontamination. The procedure was as follows. First, the IP was kept for approximately twelve hours, and then it was processed [image (A)] as well as a clinical processing mode. Second, using a wet-type chemical wiper, we scavenged the IP to remove the adhered RI on its surface. Then, once again, the IP was kept for approximately fifteen hours and processed [image (B)] in order to check an effect of decontamination. Finally, the two images of (A) and (B) were analyzed using ImageJ, which can be downloaded as a free software, and a percentage of removal was calculated. The procedure was applied to two IPs using the FCR 5501 plus. In the present case, the percentage of removal was approximately 96%. The removed radioisotopes in the chemical wipers were analyzed by Ge detector. Then, (134)Cs and (137)Cs were found with activities of 2.9 4.3 Bq and 3.5 5.2 Bq, respectively. For three months after that, we cannot see black spots on the IPs owing to the contamination of the RI and there are no defects caused by decontamination using a wet-type chemical wiper. PMID:22449904

Onuma, Yoji; Hayashi, Michiko; Hayashi, Hiroaki; Nishihara, Sadamitsu

2012-01-01

422

Technology development for a Stirling radioisotope power system  

NASA Astrophysics Data System (ADS)

NASA Glenn Research Center and the Department of Energy are developing a Stirling convertor for an advanced radioisotope power system to provide spacecraft on-board electric power for NASA deep space missions. NASA Glenn is addressing key technology issues through the use of two NASA Phase II SBIRs with Stirling Technology Company (STC) of Kennewick, WA. Under the first SBIR, STC demonstrated a synchronous connection of two thermodynamically independent free-piston Stirling convertors and a 40 to 50 fold reduction in vibrations compared to an unbalanced convertor. The second SBIR is for the development of an Adaptive Vibration Reduction System (AVRS) that will essentially eliminate vibrations over the mission lifetime, even in the unlikely event of a failed convertor. This paper presents the status and results for these two SBIR projects and also discusses a new NASA Glenn in-house project to provide supporting technology for the overall Stirling radioisotope power system development. Tasks for this new effort include convertor performance verification, controls development, heater head structural life assessment, magnet characterization and thermal aging tests, FEA analysis for a lightweight alternator concept, and demonstration of convertor operation under launch and orbit transfer load conditions. .

Thieme, Lanny G.; Qiu, Songgang; White, Maurice A.

2000-01-01

423

GRC Supporting Technology for NASA's Advanced Stirling Radioisotope Generator (ASRG)  

NASA Astrophysics Data System (ADS)

From 1999-2006, the Glenn Research Center (GRC) supported a NASA project to develop a high-efficiency, nominal 110-We Stirling Radioisotope Generator (SRG110) for potential use on NASA missions. Lockheed Martin was selected as the System Integration Contractor for the SRG110, under contract to the Department of Energy (DOE). The potential applications included deep space missions, and Mars rovers. The project was redirected in 2006 to make use of the Advanced Stirling Convertor (ASC) that was being developed by Sunpower, Inc. under contract to GRC, which would reduce the mass of the generator and increase the power output. This change would approximately double the specific power and result in the Advanced Stirling Radioisotope Generator (ASRG). The SRG110 supporting technology effort at GRC was replanned to support the integration of the Sunpower convertor and the ASRG. This paper describes the ASRG supporting technology effort at GRC and provides details of the contributions in some of the key areas. The GRC tasks include convertor extended-operation testing in air and in thermal vacuum environments, heater head life assessment, materials studies, permanent magnet characterization and aging tests, structural dynamics testing, electromagnetic interference and electromagnetic compatibility characterization, evaluation of organic materials, reliability studies, and analysis to support controller development.

Schreiber, Jeffrey G.; Thieme, Lanny G.

2008-01-01

424

High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

NASA Astrophysics Data System (ADS)

In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140° C while the heat losses caused by the addition of the VCHP are 1.8 W.

Tarau, Calin; Walker, Kara L.; Anderson, William G.

2009-03-01

425

Radioisotope Thermoelectric Generator Options for Pluto Fast Flyby Mission  

NASA Astrophysics Data System (ADS)

A small spacecraft design for the Pluto Fast Flyby (PFF) mission is under study by the Jet Propulsion Laboratory (PL) for the National Aeronautics and Space Administration (NASA), for a possible launch as early as 1998. JPL's 1992 baseline design calls for a power source able to furnish an energy output of 3963 kWh and a power output of 69 Watts(e) at the end of the 9.2-year mission. Satisfying those demands is made difficult because NASA management has set a goal of reducing the spacecraft mass from a baseline value of 166 kg to ~110 kg, which implies a mass goal of less than 10 kg for the power source. To support the ongoing NASA/JPL studies, the Department of Energy's Office of Special Applications (DOE/OSA) commissioned Fairchild Space to prepare and analyze conceptual designs of radioisotope power systems for the PFF mission. Thus far, a total of eight options employing essentially the same radioisotope heat source modules were designed and subjected to thermal, electrical, structural, and mass analyses by Fairchild. Five of these - employing thermoelectric converters - are described in the present paper, and three - employing free-piston Stirling converters - are described in the companion paper presented next. The system masses of the thermoelectric options ranged from 19.3 kg to 10.2 kg. In general, the options requiring least development are the heaviest, and the lighter options require more development with greater programmatic risk.

Schock, Alfred

1994-07-01

426

Multi-Watt Small Radioisotope Thermoelectric Generator Conceptual Design Study  

NASA Astrophysics Data System (ADS)

A need has been identified for a small, light-weight, reliable power source using a radioisotope heat source, to power the next generation of NASA's small surface rovers and exploration probes. Unit performance, development costs, and technical risk are key criteria to be used to select the best design approach. Because safety can be a major program cost and schedule driver, RTG designs should utilize the DOE radioisotope safety program's data base to the maximum extent possible. Other aspects important to the conceptual design include: 1) a multi-mission capable design for atmospheric and vacuum environments, 2) a module size based on one GPHS Step 2 module, 3) use of flight proven thermoelectric converter technologies, 4) a long service lifetime of up to 14 years, 5) maximize unit specific power consistent with all other requirements, and 6) be ready by 2013. Another critical aspect of the design is the thermal integration of the RTG with the rover or probe's heat rejection subsystem and the descent vehicle's heat rejection subsystem. This paper describes two multi-watt RTG design concepts and their integration with a MER-class rover.

Determan, William R.; Otting, William; Frye, Patrick; Abelson, Robert; Ewell, Richard; Miyake, Bob; Synder, Jeff

2007-01-01

427

Boron-Loaded Silicone Rubber Scintillators  

SciTech Connect

Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.

Bell, Z.W.; Maya, L.; Brown, G.M.; Sloop, F.V.Jr

2003-05-12

428

Density separation of boron particles. Final report  

SciTech Connect

A density distribution much broader than expected was observed in lots of natural boron powder supplied by two different sources. The material in both lots was found to have a rhombohedral crystal structure, and the only other parameters which seemed to account for such a distribution were impurities within the crystal structure and varying isotopic ratios. A separation technique was established to isolate boron particles in narrow densty ranges. The isolated fractions were subsequently analyzed for B/sup 10/ and total boron content in an effort to determine whether selective isotopic enrichment and nonhomogeneous impurity distribution were the causes for the broad density distribution of the boron powders. It was found that although the B/sup 10/ content remained nearly constant around 18%, the total boron content varied from 37.5 to 98.7%. One of the lots also was found to contain an apparently high level of alpha rhombohedral boron which broadened the density distribution considerably. During this work, a capability for removing boron particles containing gross amounts of impurities and, thereby, improving the overall purity of the remaining material was developed. In addition, the separation technique used in this study apparently isolated particles with alpha and beta rhombohedral crystal structures, although the only supporting evidence is density data.

Smith, R.M.

1980-04-01

429

Icosahedral B{sub 12}, macropolyhedral boranes, {beta}-rhombohedral boron and boron-rich solids  

SciTech Connect

The preference for icosahedral B{sub 12} amongst polyhedral boranes and elemental boron is explained based on an optimization of overlap model. The ingenious ways in which elemental boron and boron-rich solids achieve icosahedron-related structures are explained by a fragment approach. The Jemmis mno rules are used to get the electron requirements. The extra occupancies and vacancies in {beta}-rhombohedral structures are shown to be inevitable results of electron requirements. The detailed understanding of the structure suggests ways of doping {beta}-rhombohedral boron with metals for desired properties. Theoretical studies of model {beta}-rhombohedral solids with metal dopings provide support for the analysis. - Graphical abstract: A short legend: Principal building blocks B{sub 12}, B{sub 57}, and B{sub 84} of elemental boron and boron-rich solids.

Jemmis, Eluvathingal D. [School of Chemistry, University of Hyderabad, Hyderabad 500046 (India) and Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 (India)]. E-mail: jemmis@ipc.iisc.ernet.in; Prasad, Dasari L.V.K. [School of Chemistry, University of Hyderabad, Hyderabad 500046 (India); Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 (India)

2006-09-15

430

Methods for boron analysis in boron neutron capture therapy (BNCT). A review  

Microsoft Academic Search

The possibilities and limitations of the numerous individual methods used for boron analysis for BNCT in clinical and biological\\u000a samples are reported in detail. The main interferences of the analytical methods are described. Sample pretreatment techniques\\u000a are discussed. The methods reviewed for boron analysis for BNCT concern atomic spectrometry, radioanalytical methods, and\\u000a imaging techniques. An error analysis of boron determinations

Thomas U. Probst

1999-01-01

431

Boronated DNA-binding compounds as potential agents for boron neutron capture therapy.  

PubMed

Boron Neutron Capture Therapy (BNCT) is a binary cancer treatment that exploits the short range particles released from a nuclear fission reaction involving the non-radioactive 10B nucleus and low-energy (thermal) neutrons for the destruction of tumour cells. If boronated agents are targeted towards chromosomal DNA, the efficiency of BNCT is greatly enhanced. This article presents a concise review of DNA-binding compounds that have been functionalised with boron. PMID:17346220

Crossley, Ellen L; Ziolkowski, Erin J; Coderre, Jeffrey A; Rendina, Louis M

2007-03-01

432

Boron-10 Lined Proportional Counter Wall Effects  

SciTech Connect

The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube based system in the configuration of a coincidence counter. This report provides information about how variations in proportional counter radius and gas pressure in a typical coincident counter design might affect the observed signal from boron-lined tubes. A discussion comparing tubes to parallel plate counters is also included.

Siciliano, Edward R.; Kouzes, Richard T.

2012-05-01

433

Preparation and Study of High Purity Boron-Group Five Compounds.  

National Technical Information Service (NTIS)

The report summarizes the results of a twenty month study of various compounds of boron with the group five elements phosphorus, arsenic, and antimony. Methods of preparation of high purity boron phosphide, boron subphosphide, and boron subarsenide were u...

J. A. Reising J. T. Buford R. I. Gross

1973-01-01

434

Ground-state properties of boron-doped diamond  

SciTech Connect

Boron-doped diamond undergoes an insulator-metal or even a superconducting transition at some critical value of the dopant concentration. We study the equilibrium lattice parameter and bulk modulus of boron-doped diamond experimentally and in the framework of the density functional method for different levels of boron doping. We theoretically consider the possibility for the boron atoms to occupy both substitutional and interstitial positions and investigate their influence on the electronic structure of the material. The data suggest that boron softens the lattice, but softening due to substitutions of carbon with boron is much weaker than due to incorporation of boron into interstitial positions. Theoretical results obtained for substitution of carbon are in very good agreement with our experiment. We present a concentration dependence of the lattice parameter in boron-doped diamond, which can be used for to identify the levels of boron doping in future experiments.

Zarechnaya, E. Yu., E-mail: ezarechnaya@yahoo.com; Isaev, E. I. [Moscow State Institute of Steel and Alloys (Technological University) (Russian Federation)], E-mail: eyvaz_isaev@yahoo.com; Simak, S. I. [Linkoeping University, Department of Physics, Chemistry, and Biology (IFM) (Sweden); Vekilov, Yu. Kh. [Moscow State Institute of Steel and Alloys (Technological University) (Russian Federation); Dubrovinsky, L. S. [University of Bayreuth, Bayerisches Geoinstitut (Germany); Dubrovinskaia, N. A. [University of Heidelberg, Mineralogisches Institut (Germany); Abrikosov, I. A. [Linkoeping University, Department of Physics, Chemistry, and Biology (IFM) (Sweden)

2008-04-15

435

Boron-doped diamond microdisc arrays: electrochemical characterisation and their use as a substrate for the production of microelectrode arrays of diverse metals (Ag, Au, Cu)via electrodeposition.  

PubMed

A novel boron-doped diamond (BDD) microelectrode array is characterised with electrochemical and atomic force microscopic techniques. The array consists of 40 micron-diameter sized BDD discs which are separated by 250 microns from their nearest neighbour in a hexagonal arrangement. The conducting discs can be electroplated to produce arrays of copper, silver or gold for analytical purposes in addition to operating as an array of BDD-microelectrodes. Proof-of-concept is shown for four separate examples; a gold plated array for arsenic detection, a copper plated array for nitrate analysis, a silver plated array for hydrogen peroxide monitoring and last, cathodic stripping voltammetry for lead at the bare BDD-array. PMID:16096678

Simm, Andrew O; Banks, Craig E; Ward-Jones, Sarah; Davies, Trevor J; Lawrence, Nathan S; Jones, Timothy G J; Jiang, Li; Compton, Richard G

2005-08-01

436

Determination and Standardization of Analytical Conditions for Dissolved Boron in Coastal Waters of East Sea in Korea by ICP-OES  

NASA Astrophysics Data System (ADS)

The analysis of metals in seawaters has been an important subject for many years. Achieving low-level detection limits as well as overcoming high matrix effect are requested in seawater analysis especially elements of interest are present in various chemical forms. Among them, boron is one of the widely distributed elements in nature and its concentrations of about 10 ppm in the Earth's crust and about 4.5 ppm in the seawater as borates. In seawater boron concentration exhibit a linear relationship to the amount of chloride ion present. Boron had been considered as one of the valuable elements to recover from seawaters for commercial use. Currently, we launched research team for the production of valuable metals from seawaters in Korea that can be used commercially. Several metals including boron were already under serious studies. In this study we aim to prepare standardized operational procedures in analysis of boron during pilot study for boron recovery as pilot recovery process. Inductively coupled plasma Optical Emission Spectrometry (ICP-OES) method is preferred for the analysis of the low levels of boron found in environmental samples such as seawater. In order to develop test method for the determination of dissolved Boron from East Sea Seawater in Korea, all soluble boron present in seawater has been tested and accuracy of measurement was checked from the sampling step. The result of analysis of boron in seawaters presents many difficult problems, ionization of from the alkali and alkaline earth metals. And the problems also exist in handling nebulizer and injector tubes in high saline solutions. The scope of this study was to determine boron which can contain up to 35psu dissolved salt. The work also included comparing various analytical methods for better accurate results in several solution conditions. Dilution, standard addition, matrix matching calibration methods was thoroughly tested differently and detailed operating conditions for using auxiliary gases were also presented.

Yoon, H.; Shin, M.; Yoon, C.; Lee, J.

2005-12-01

437

Synthesis and evaluation of cyclic RGD-boron cluster conjugates to develop tumor-selective boron carriers for boron neutron capture therapy  

Microsoft Academic Search

Boron-containing agents play a key role in successful boron neutron capture therapy (BNCT). Icosahedral boron cluster-Arg-Gly-Asp (RGD) peptide conjugates were designed, synthesized, and evaluated for the biodistribution to develop tumor-selective boron carriers. Integrin ?v?3 is an attractive target for anti-tumor drug delivery because of its specific expression in proliferating endothelial and tumor cells of various origins. We, therefore, selected a

Sadaaki Kimura; Shin-ichiro Masunaga; Tomohiro Harada; Yasuo Kawamura; Satoshi Ueda; Kensuke Okuda; Hideko Nagasawa

2011-01-01

438

Abstracts of Papers from the International Symposium on Boron, Held at Tiflis, on 9-11 October 1972.  

National Technical Information Service (NTIS)

Contents: Thermal conductivity of boron and its compounds; Theory of the thermal conductivity of crystalline boron; Study of the nature of current carriers in boron; Study of some properties of pure and alloyed boron; Some properties of boron alloyed with...

1973-01-01

439

BORON, MANGANESE, MOLYBDENUM, NICKEL, SILICON, AND VANADIUM  

Technology Transfer Automated Retrieval System (TEKTRAN)

Although boron, manganese, molybdenum, nickel, silicon and vanadium are not considered significant nutritional concerns, they have received some attention in the sports nutrition field because of findings suggesting that they could enhance strength, performance and endurance in athletic activities. ...

440

Normal Modes in Hexagonal Boron Nitride.  

National Technical Information Service (NTIS)

Pyrolytic boron nitride, a rather anisotropic material among the III-V compounds was investigated in reflection and transmission, using polarized infrared radiation in the spectral range from 100/cm to 3000/cm. The reflection spectra were analyzed by mean...

R. Geick C. H. Perry G. Rupprecht

1966-01-01

441

Sensitivity of Vertebrate Embryos to Boron Compounds.  

National Technical Information Service (NTIS)

Developmental stages of rainbow trout, channel catfish, goldfish, leopard frog, and Fowler's toad were treated in a continuous flow system with boric acid and borax concentrations ranging from 0.001-300 ppm boron. Exposure was initiated subsequent to fert...

J. A. Black W. J. Birge

1977-01-01

442

Boron strengthening in FeAl  

SciTech Connect

The effect of boron on the strength of B2-structured FeAl is considered as a function of composition, grain size and temperature. Boron does not affect the concentrations of antisite atoms or vacancies present, with the former increasing and the latter decreasing with increasing deviation from the stoichiometric composition. When vacancies are absent, the strength increase per at. % B per unit lattice strain, {Delta}{sigma}/({Delta}c x {epsilon}) increases with increasing aluminum concentration, but when vacancies are present (>45 at. % Al), {Delta}{sigma}/({Delta}c x {epsilon}) decreases again. Boron increases grain size strengthening in FeAl. B strengthening is roughly independent of temperature up to the yield strength peak but above the point, when diffusion-assisted deformation occurs, boron strengthening increases dramatically.

Baker, I.; Li, X.; Xiao, H.; Klein, O.; Nelson, C. [Dartmouth Coll., Hanover, NH (United States). Thayer School of Engineering; Carleton, R.L.; George, E.P. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1998-11-01

443

Interaction of boron halides with carbon preparations  

SciTech Connect

The authors investigated the interaction of boron trichloride and boron tribromide vapor with hydroxyl functional groups of the surfaces of diamond and technical carbon at vapor pressures in the range 0.33-3.52 kPa and at temperatures in the range 32-200/sup 0/C. The interaction of boron halides with the surfaces of preparations of diamond and technical carbon at temperatures of 32-300/sup 0/C and pressures of 0.33-3.52 kPa goes irreversibly. The rate of adsorption of boron halides is described by a kinetic equation for a homogeneous surface. The activation energies of chemisorption and the rate constants were found.

Gavrilin, A.V.; Luk'yanov, I.M.; Smirnov, E.P.; Aleskovskii, V.B.

1987-12-10

444

Boron adsorption by excised sunflower root  

Microsoft Academic Search

Boron, a vital plant nutrient, possesses certain characteristics similar to phosphate ion. For this reason, some researchers believe that its absorption by plants is similar to phosphate ion absorption.

Hirofumi Tanaka

1967-01-01

445

Fatigue of Boron-Aluminum Composites.  

National Technical Information Service (NTIS)

The mechanisms of fatigue failure in composites of boron-6061 aluminum under oscillating tensile loads were determined and a phenomenological model of fatigue failure is outlined. A linear relationship between fatigue limit and filament content is suggest...

J. R. Hancock

1972-01-01

446

Titanium Reinforced Boron-Polyimide Composite.  

National Technical Information Service (NTIS)

Processing techniques for boron polyimide prepreg were developed whereby composites could be molded under vacuum bag pressure only. A post-cure cycle was developed which resulted in no loss in room temperature mechanical properties of the composite at any...

G. A. Clark K. I. Clayton

1969-01-01

447

Synthesis of boron-containing primary amines.  

PubMed

In this study, boron-containing primary amines were synthesized for use as building blocks in the study of peptoids. In the first step, Gabriel synthesis conditions were modified to enable the construction of seven different aminomethylphenyl boronate esters in good to excellent yields. These compounds were further utilized to build peptoid analogs via an Ugi four-component reaction (Ugi-4CR) under microwave irradiation. The prepared Ugi-4CR boronate esters were then successfully converted to the corresponding boronic acids. Finally, the peptoid structures were successfully modified by cross-coupling to aryl/heteroaryl chlorides via a palladium-mediated Suzuki coupling reaction to yield the corresponding derivatives in moderate to good yields. PMID:24108399

Chung, Sheng-Hsuan; Lin, Ting-Ju; Hu, Qian-Yu; Tsai, Chia-Hua; Pan, Po-Shen

2013-10-08

448

Irradiation of strontium chloride targets at proton energies above 35 MeV to produce PET radioisotope Y-86  

SciTech Connect

Proton irradiation of natural and enriched SrCl{sub 2} targets was used to produce PET radioisotope {sup 86}. The proton energy was degraded from the incident 117.8 MeV to induce the {sup 88}Sr(p,3n) reaction. For the irradiation three pellets made of {sup nat}SrCl{sub 2} (6.61 and 74.49 g) and {sup 88}SrCl{sub 2} (5.02 g) were pressed and individually encapsulated in stainless steel target bodies. The two smaller targets were irradiated for 0.5-1 h at the energy - 46 {yields} 37 MeV to take advantage of the peak in the excitation function of the {sup 88}Sr(p,3n) reaction. The larger target was irradiated at 66.4 {yields} 44.6 MeV. The irradiated pellets were chemically processed to selectively separate {sup 86}Y radioisotope using Eichrom DGA (N,N,N{prime},N{prime}-tetra-n-octyldiglycolamide) resin. The production yields of {sup 86}Y were determined to be 10-13 mCi/{mu}A h. Coproduction of {sup 87m}Y in the final product was 34% for {sup nat}SrCl{sub 2} and 54% for {sup 88}SrCl{sub 2} target. The chemical separation yield of yttrium reached 88-92%. The developed chemical procedure allows for the same day processing and shipment of the isotope to users.

Medvedev D. G.; Mausner, L.F.; Srivastava, S.C.

2011-12-01

449

Theoretical dosimetry estimations for radioisotopes produced by proton-induced reactions on natural and enriched molybdenum targets  

NASA Astrophysics Data System (ADS)

This study presents a summary of the dosimetry calculations performed for three technetium agents most commonly used in nuclear medicine diagnostic studies, namely sestamibi™, phosphonates and pertechnetate, labeled with cyclotron-produced technetium. Calculated patient doses were compared to those that would be delivered by the same radiotracers labeled with technetium obtained from a generator produced in a reactor. The main difference is that technetium from a generator is pure, i.e. contains only 99mTc and its decay product 99gTc, while in a cyclotron a large number of other stable and radioactive isotopes are created. In our calculations only technetium radioisotopes (ground and isomeric states) were considered as they will be included in the radiotracer labeling process and will contribute to the patient dose. Other elements should be removed by chemical purification. These dose estimates are based on our theoretical calculations of the proton-induced reaction cross sections and radioisotope production yields. Thick targets of enriched (three different compositions) and natural molybdenum, and three initial beam energies (16, 19 and 24 MeV) were considered for irradiation times of 3, 6 and 12 h with a beam current of 200 µA. The doses were calculated for injection times corresponding to 0, 2, 8, 12 and 24 h after the end of beam.

Hou, X.; Celler, A.; Grimes, J.; Bénard, F.; Ruth, T.

2012-03-01

450

Theoretical dosimetry estimations for radioisotopes produced by proton-induced reactions on natural and enriched molybdenum targets.  

PubMed

This study presents a summary of the dosimetry calculations performed for three technetium agents most commonly used in nuclear medicine diagnostic studies, namely sestamibi™, phosphonates and pertechnetate, labeled with cyclotron-produced technetium. Calculated patient doses were compared to those that would be delivered by the same radiotracers labeled with technetium obtained from a generator produced in a reactor. The main difference is that technetium from a generator is pure, i.e. contains only (99m)Tc and its decay product (99g)Tc, while in a cyclotron a large number of other stable and radioactive isotopes are created. In our calculations only technetium radioisotopes (ground and isomeric states) were considered as they will be included in the radiotracer labeling process and will contribute to the patient dose. Other elements should be removed by chemical purification. These dose estimates are based on our theoretical calculations of the proton-induced reaction cross sections and radioisotope production yields. Thick targets of enriched (three different compositions) and natural molybdenum, and three initial beam energies (16, 19 and 24 MeV) were considered for irradiation times of 3, 6 and 12 h with a beam current of 200 µA. The doses were calculated for injection times corresponding to 0, 2, 8, 12 and 24 h after the end of beam. PMID:22391011

Hou, X; Celler, A; Grimes, J; Bénard, F; Ruth, T

2012-03-05

451

Novel boron nitride hollow nanoribbons.  

PubMed

Novel BN hollow nanoribbons (BNHNRs) were fabricated by a simple ZnS nanoribbon templating method. Such BNHNRs have a distinct structure and show unique optical properties, as demonstrated from Raman, Fourier transform infrared spectroscopy, UV-vis spectroscopy, and cathodoluminescence spectroscopy, when compared with other forms of BN nanostructures. With high crystallinity, the BNHNRs exhibit an extraordinary ultraviolet CL emission at 5.33 eV. Such a property is highly advantageous for optoelectronic applications, particularly in the ultraviolet region, such as blue lasing and light emitting diodes. This templating method has also been extended to synthesize other hollow nanostructures such as boron carbonitride. This study represents a new methodology for fabricating hollow nanostructures with defined crystallinity and unique optical properties. PMID:19206466

Chen, Zhi-Gang; Zou, Jin; Liu, Gang; Li, Feng; Wang, Yong; Wang, Lianzhou; Yuan, Xiao-Li; Sekiguchi, Takashi; Cheng, Hui-Ming; Lu, Gao Qing

2008-10-28

452

Characterization of Boron Contamination in Fluorine Implantation using Boron Trifluoride as a Source Material  

NASA Astrophysics Data System (ADS)

Fluorine implantation process purity was considered on different types of high current implanters. It was found that implanters equipped with an indirectly heated cathode ion source show an enhanced deep boron contamination compared to a high current implanter using a cold RF-driven multicusp ion source when boron trifluoride is used for fluorine implantations. This contamination is directly related to the source technology and thus, should be considered potentially for any implanter design using hot cathode/hot filament ion source, independently of the manufacturer. The boron contamination results from the generation of double charged boron ions in the arc chamber and the subsequent charge exchange reaction to single charged boron ions taking place between the arc chamber and the extraction electrode. The generation of the double charged boron ions depends mostly on the source parameters, whereas the pressure in the region between the arc chamber and the extraction electrode is mostly responsible for the charge exchange from double charged to single charged ions. The apparent mass covers a wide range, starting at mass 11. A portion of boron ions with energies of (19/11) times higher than fluorine energy has the same magnetic rigidity as fluorine beam and cannot be separated by the analyzer magnet. The earlier described charge exchange effects between the extraction electrode and the entrance to the analyzer magnet, however, generates boron beam with a higher magnetic rigidity compared to fluorine beam and cannot cause boron contamination after mass-separation. The energetic boron contamination was studied as a function of the ion source parameters, such as gas flow, arc voltage, and source magnet settings, as well as analyzing magnet aperture resolution. This allows process optimization reducing boron contamination to the level acceptable for device performance.

Schmeide, Matthias; Kondratenko, Serguei

2011-01-01

453

Characterization of Boron Contamination in Fluorine Implantation using Boron Trifluoride as a Source Material  

SciTech Connect

Fluorine implantation process purity was considered on different types of high current implanters. It was found that implanters equipped with an indirectly heated cathode ion source show an enhanced deep boron contamination compared to a high current implanter using a cold RF-driven multicusp ion source when boron trifluoride is used for fluorine implantations. This contamination is directly related to the source technology and thus, should be considered potentially for any implanter design using hot cathode/hot filament ion source, independently of the manufacturer.The boron contamination results from the generation of double charged boron ions in the arc chamber and the subsequent charge exchange reaction to single charged boron ions taking place between the arc chamber and the extraction electrode. The generation of the double charged boron ions depends mostly on the source parameters, whereas the pressure in the region between the arc chamber and the extraction electrode is mostly responsible for the charge exchange from double charged to single charged ions. The apparent mass covers a wide range, starting at mass 11. A portion of boron ions with energies of (19/11) times higher than fluorine energy has the same magnetic rigidity as fluorine beam and cannot be separated by the analyzer magnet. The earlier described charge exchange effects between the extraction electrode and the entrance to the analyzer magnet, however, generates boron beam with a higher magnetic rigidity compared to fluorine beam and cannot cause boron contamination after mass-separation.The energetic boron contamination was studied as a function of the ion source parameters, such as gas flow, arc voltage, and source magnet settings, as well as analyzing magnet aperture resolution. This allows process optimization reducing boron contamination to the level acceptable for device performance.

Schmeide, Matthias [Infineon Technologies Dresden GmbH, Koenigsbruecker Str. 180, D-01099 Dresden (Germany); Kondratenko, Serguei [Axcelis Technologies, Inc., 108 Cherry Hill Dr., Beverly, MA (United States)

2011-01-07

454

[Boron balance in agroecosystem on brown-red soil of south Hubei Province].  

PubMed

Five sequential cropping systems including rape/soybean-rice, wheat/watermelon-rice, rape/corn-soybean, wheat-sesame and soybean-sesame, were selected study the boron balance in agroecosystem on brown-red soil of south Hubei Province. The results show that the main output of boron was runoff and leaching, which accounted for 48-53% and 41% of the total respectively, while the output by products accounted for 3.4-10.1%. The main inputs were from rainfall, irrigation, fertilization seeds and seedlings, and natural return. PMID:11767601

Cao, C; Cai, C; Zhang, G; Wang, Y

2000-04-01

455

Boron isotope variations in nature: a synthesis  

Microsoft Academic Search

The large relative mass difference between the two stable isotopes of boron, 10B and 11B, and the high geochemical reactivity of boron lead to significant isotope fractionation by natural processes. Published 11B values (relative to the NBS SRM-951 standard) span a wide range of 90. The lowest 11B values around — 30 are reported for non-marine evaporite minerals and certain

S. Barth

1993-01-01

456

Boron impregnation treatment of Eucalyptus grandis wood  

Microsoft Academic Search

Eucalyptus grandis is suitable for small timber purposes, but its wood is reported to be non-durable and difficult to treat. Boron compounds being diffusible, and the vacuum-pressure impregnation (VPI) method being more suitable for industrial-scale treatment, the possibility of boron impregnation of partially dry to green timber was investigated using a 6% boric acid equivalent (BAE) solution of boric acid

T. K. Dhamodaran; R. Gnanaharan

2007-01-01

457

Oxidation behaviour of boron carbide powder  

Microsoft Academic Search

Isothermal oxidation behaviour of powdered boron carbide (B4C) with the fine (1.52?m), medium (22.5?m) and coarse (59.6?m) particle size has been studied in air ranging from 500 to 800°C. The oxidation rate strongly depends on the particle size of boron carbide and temperature. The smaller particle size the higher oxidation rate of B4C powder due to its larger surface area.

Y. Q. Li; T. Qiu

2007-01-01

458

The Alcator C-Mod Boronization System  

Microsoft Academic Search

A system for boronization of the Alcator C-Mod vacuum vessel and plasma facing components was installed and began routine operation in January of 1996. Significant suppression of impurity levels and record stored energy were achieved during ICRF heating following boronization. Electron cyclotron discharge cleaning in dilute diborane gas (10% D_2B_6, 90% helium) was selected as the simplest and most cost

C. Reddy; C. L. Fiore; J. Irby; J. Bosco; R. Childs; E. Marmar; G. McCracken; G. Esser; J. Winter; M. Hawthorne; R. Watson

1996-01-01

459

Hydrogen storage in boron substituted carbon nanotubes  

Microsoft Academic Search

Template assisted synthesis of boron substituted carbon nanotubes was carried out by the carbonization of hydroborane polymer in alumina membrane template. The nanotubes were characterized by electron microscopic analysis, FT-Raman, FT-IR, XRD, X-ray photoelectron spectroscopy (XPS) and 13C &11B MAS NMR techniques. The presence of boron in different chemical environment has been visualized by XPS and 11B MAS NMR. The

M. Sankaran; B. Viswanathan

2007-01-01

460

Hard and tough boron suboxide based composites  

Microsoft Academic Search

Boron suboxide (B6O) powder was synthesized at temperatures of about 1400°C from the reaction of amorphous boron powder with boric acid. The synthesized B6O powders were hot pressed at temperatures up to 1900°C and at pressures of 50MPa. Additionally to pure B6O materials, composites with aluminium were prepared. The microstructure and properties of the sintered compacts were investigated. The addition

T. C. Shabalala; D. S. McLachlan; I. Sigalas; M. Herrmann

2008-01-01

461

Conversion electron and X-ray Mössbauer studies of boronized low-carbon steel under corrosion and oxidation conditions  

NASA Astrophysics Data System (ADS)

Iron-boride layers on low-carbon steel were produced by thermochemical diffusion process. The surface interaction products: Fe2B, FeB, FeBx (x>1) and a solid solution of iron in boron were identified by surface Mössbauer spectroscopy (CEMS and XMS). Samples of original and boronized steel were subjected to corrosion process by immersion in HCl (0.1 N) solution for 150 h. While the steel sample was strongly corroded, none corrosion product was found on the boronized sample surface. However, significant changes in relative percentages of the various iron boride phases were detected. Also, samples of original and boronized steel were subjected to oxidation process by heat-treatment in air at 300°C for 8 h and 500°C for 4 h. At 300°C, while bulk Fe3O4 and ?-Fe2O3 were formed on the steel surface, none iron oxide was detected on the boronized surface. At 500° C, while only pure bulk ?-Fe2O3 was detected on the steel surface, a particle size distribution of ?-Fe2O3, with particle size of about 100 Å, was probably formed on the boronized surface, as evidenced by CEMS.

Abras, A.; Campos, A. A. G.; de Carvalho, A. V.; Ladeira, L. O.

1986-11-01

462

Full-scale simulation of seawater reverse osmosis desalination processes for boron removal: Effect of membrane fouling.  

PubMed

The objective of this study is to further develop previously reported mechanistic predictive model that simulates boron removal in full-scale seawater reverse osmosis (RO) desalination processes to take into account the effect of membrane fouling. Decrease of boron removal and reduction in water production rate by membrane fouling due to enhanced concentration polarization were simulated as a decrease in solute mass transfer coefficient in boundary layer on membrane surface. Various design and operating options under fouling condition were examined including single- versus double-pass configurations, different number of RO elements per vessel, use of RO membranes with enhanced boron rejection, and pH adjustment. These options were quantitatively compared by normalizing the performance of the system in terms of E(min), the minimum energy costs per product water. Simulation results suggested that most viable options to enhance boron rejection among those tested in this study include: i) minimizing fouling, ii) exchanging the existing SWRO elements to boron-specific ones, and iii) increasing pH in the second pass. The model developed in this study is expected to help design and optimization of the RO processes to achieve the target boron removal at target water recovery under realistic conditions where membrane fouling occurs during operation. PMID:22578430

Park, Pyung-Kyu; Lee, Sangho; Cho, Jae-Seok; Kim, Jae-Hong

2012-04-21

463

Boron stress responsive microRNAs and their targets in barley.  

PubMed

Boron stress is an environmental factor affecting plant development and production. Recently, microRNAs (miRNAs) have been found to be involved in several plant processes such as growth regulation and stress responses. In this study, miRNAs associated with boron stress were identified and characterized in barley. miRNA profiles were also comparatively analyzed between root and leave samples. A total of 31 known and 3 new miRNAs were identified in barley; 25 of them were found to respond to boron treatment. Several miRNAs were expressed in a tissue specific manner; for example, miR156d, miR171a, miR397, and miR444a were only detected in leaves. Additionally, a total of 934 barley transcripts were found to be specifically targeted and degraded by miRNAs. In silico analysis of miRNA target genes demonstrated that many miRNA targets are conserved transcription factors such as Squamosa promoter-binding protein, Auxin response factor (ARF), and the MYB transcription factor family. A majority of these targets were responsible for plant growth and response to environmental changes. We also propose that some of the miRNAs in barley such as miRNA408 might play critical roles against boron exposure. In conclusion, barley may use several pathways and cellular processes targeted by miRNAs to cope with boron stress. PMID:23555702

Ozhuner, Esma; Eldem, Vahap; Ipek, Arif; Okay, Sezer; Sakcali, Serdal; Zhang, Baohong; Boke, Hatice; Unver, Turgay

2013-03-26

464

Risk of boron and heavy metal pollution from agro-industrial wastes applied for plant nutrition.  

PubMed

In this study, the effects of various agro-industrial wastes were investigated when applied to soil alone or in combination with chemical fertilizers, regarding the risks of boron and heavy metal pollution of soils and plants. Nine combinations of production residues from various agro-industries, urban wastes, and mineral fertilizers were applied to potatoes in a field experiment. The content of available boron in the soil differed significantly (p < 0.05) among the applications. Generally, B values were found to be slightly higher when soapstock, prina, and blood were used alone or in combination. Although total Co, Cd, and Pb contents of soils showed no significant differences between the applications, Cr content differed significantly (p < 0.05). No pollution risk was observed in soil in respect to total Co, Cd, Pb, and Cr contents. The amount of boron and heavy metals in leaves showed no significant differences among the applications. Cobalt, Cd, and Pb in leaves were at normal levels whereas Cr was slightly above normal but well under the critical level. Boron was low in tubers and varied significantly between applications such as Co and Cd. The Co content of tubers was high, Cd and Cr contents were below average, and Pb content was between the given values. Some significant correlations were found between soil characteristics and the boron and heavy metal content of soil, leaves, and tubers. PMID:19680756

Seçer, Müzeyyen; Ceylan, Safak; Elmaci, Omer Lütfü; Akdemir, Hüseyin

2009-08-13

465

Secret of formulating a selective etching or cleaning solution for boron nitride (BN) thin film  

NASA Astrophysics Data System (ADS)

Boron nitride thin film has a very unique characteristic of extremely high chemical inertness. Thus, it is a better hard mask than silicon nitride for aggressive etching solutions, such as the isotropic HF/HNO3/CH3COOH (or HNA) etchant for silicon. However, because of its high chemical inertness, it is also difficult to remove it. Plasma etching with Freon gases can etch the boron nitride film, but it is unselective to silicon, silicon dioxide or silicon nitride. Cleaning up the boron nitride film with plasma etching will usually leave a damaged or foggy surface. A special wet chemical solution has been developed for etching or cleaning boron nitride film selectively. It can etch boron nitride, but not the coatings or substrates of silicon, silicon nitride and silicon dioxide. It is a very strong oxidizing agent consisting of concentrated sulfuric acid (H2SO4) and hydrogen peroxide (H2O2), but different from the common Piranha Etch. It may be even more interesting to understand the logic or secret behind of how to formulate a new selective etching solution. Various chemical and chemical engineering aspects were considered carefully in our development process. These included creating the right electrochemical potential for the etchant, ensuring large differences in chemical kinetics to make the reactions selective, providing proper mass transfer for removing the by products, etc.

Hui, Wing C.

2004-04-01

466

Boron  

Microsoft Academic Search

This paper reports that borate minerals and refined borates are used extensively for the manufacture of vitreous materials such as insulation and textile fiberglasses, borosilicate glass, and porcelain enamels and frits. In North America, these applications are estimated to account for over 54% of the borate consumption. Other substantial uses are in soaps and detergents, metallurgy, fire retardants, industrial biocides,

Cozen

1991-01-01

467

Directionality in the GammaTracker Handheld Radioisotope Identifier  

SciTech Connect

Several computationally simple methods are presented for determining the direction to one or more point sources using the GammaTracker handheld radioisotope identifier. GammaTracker will display a heading indicating the direction to one or more sources; no gamma-ray images will be displayed to the user. The details of each directionality method are presented and performance is compared using radiation transport simulations of gamma-ray point sources at varying activity levels on a natural background. All methods achieved sufficiently high pointing accuracy and precision in the tested scenarios, which included background-to-source ratios up to 10:1. The prospects for implementation in the GammaTracker firmware architecture are discussed.

Seifert, Carolyn E.; Myjak, Mitchell J.

2009-06-01

468

End-on radioisotope thermoelectric generator impact tests  

SciTech Connect

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of [sup 238]Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). The modular GPHS design was developed to address both survivability during launch abort and return from orbit. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

Reimus, M.A.H.; Hhinckley, J.E.

1997-01-01

469

Radioisotope thermoelectric generator/thin fragment impact test  

SciTech Connect

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the convertor housing, failure of one fueled clad, and release of a small quantity of fuel.

Reimus, M.A.H.; Hinckley, J.E.

1998-12-31

470

Fabrication of light weight radioisotope heater unit hardware components  

SciTech Connect

The Light Weight Radioisotope Heater Unit (LWRHU) is planned to be used on the National Aeronautics and Space Administration (NASA) Cassini Mission, to provide localized thermal energy as strategic locations on the spacecraft. These one watt heater units will support the operation of many on-board instruments that require a specific temperature range to function properly. The system incorporates a fuel pellet encapsulated in a vented metallic clad fabricated from platinum-30{percent} rhodium (Pt-30{percent}Rh) tubing, sheet and foil materials. To complete the package, the clad assemblies are placed inside a combination of graphite components. This report describes the techniques employed by Mound related to the fabrication and sub assembly processes of the LWRHU clad hardware components. Included are details concerning configuration control systems, material procurement and certification, hardware fabrication specifics, and special processes that are utilized. {copyright} {ital 1996 American Institute of Physics.}

McNeil, D.C. [EG& G Mound Applied Technologies, P.O. Box 3000, Miamisburg, Ohio 45343-3000 (United States)

1996-03-01

471

Particle-beam accelerators for radiotherapy and radioisotopes  

NASA Astrophysics Data System (ADS)

The philosophy used in developing the PIGMI (pion generator for medical irradiation) technology was that the parameters chosen for physics research machines are not necessarily the right ones for a dedicated therapy or radioisotope machine. In particular, the beam current and energy can be optimized, and the design should emphasize minimum size, simplicity and reliability of operation, and economy in capital and operating costs. A major part of achieving these goals lay in raising the operating frequency and voltage gradient of the accelerator, which shrinks the diameter and length of the components. Several other technical innovations resulted in major system improvements. One of these is a radically new type of accelerator structure named the radio frequency quadrupole accelerator. This allowed the elimination of the large, complicated ion source used in previous ion accelerators, and a very high quality accelerated beam. Also, by using advanced permanent magnet materials to make the focusing elements, the system becomes much simpler. Other improvements are described.

Boyd, T. J., Jr.; Crandall, K. R.; Hamm, R. W.; Hansborough, L. D.; Hoeberling, R. F.; Jameson, R. A.; Knapp, E. A.; Mueller, D. W.; Potter, J. M.; Stokes, R. H.

472

[Radioisotopic diagnosis of regional lung functions in occupational lung diseases].  

PubMed

The results are reported from the radioisotope investigations of the regional blood supply, ventilation and difussion of 133 Xenon from four zones of both lungs in 78 patients with all stages of silicosis and 43 patients with chronic bronchitis--emphysema. Unsystemic and scattered focal disturbances of the separate respiration processes are established. They should be given consideration separately and together with the classical non-isotope investigations, with a view to the making of a precise functional diagnosis and occupational expertise, because they reflect the changes due to the basic disease as well as the other accompanying lung diseases as pneumosclerosis, chronic bronchitis, emphysema, tumors, etc. The complete safety, lack of unpleasant procedures for the patient and sufficient accuracy urge their wider application in practice, including as screening tests. PMID:654222

Vaskov, L

1978-01-01

473

Radioisotope thermoelectric generator/thin fragment impact test  

NASA Astrophysics Data System (ADS)

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of 238Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel.

Reimus, M. A. H.; Hinckley, J. E.

1998-01-01

474