Energy Technology Data Exchange (ETDEWEB)
Craters were produced in the surface of a Pt-specimen by plasma discharge. Using a Focussed Ion Beam (FIB), TEM-foils of the cross section of the craters were prepared in order to examine the microstructural changes occurring as a result of the discharge impact. The molten material pushed to the edge of the craters was able to be identified. The grains beneath the craters reached the surface of the crater by a mechanism of epitaxial growth. (orig.)
2005-11-01
... They often end up looking somewhat like a volcano, with a raised edge and a central crater. ...
UK PubMed Central (United Kingdom)
To examine the associations between body weight and physical, verbal, relational and cyber victimization among U.S. boys and girls in grade 6 through 10. Underweight boys and girls were more...Full Text Available
2010-07-01
A School-Based Exercise Intervention Program Increases Muscle Strength in Prepubertal Boys
UK PubMed Central (United Kingdom)
This prospective controlled intervention study over 12 months evaluated the effect of exercise on muscular function, physical ability, and body composition in pre-pubertal boys. Sixty-eight boys aged...Full Text Available
2010-01-01
LDEF impact craters formed by carbon-rich impactors
International Nuclear Information System (INIS)
Two small craters (number 74, 119 microns, and number 31, 158 microns in diameter) with depth to diameter ratios of about 0.59 and 0.8, respectively, were found in Al from the Long Duration Exposure Facility (LDEF) experiment tray A11EOOF. Both craters have residues concentrated in the crater bottoms, along the walls, and on top of the overturned rims. Low voltage scanning electron electron microscopy, Auger electron spectroscopy, time of flight secondary ion mass spectroscopy and energy dispersive x-ray spectroscopy were used to obtain high resolution imagery and elemental analysis. Analyses indicate that the impactor for both craters was carbon-rich, as the residues contain mostly C. Silicon, S, and F in low concentrations are present on the Al surface away from the craters and may be, in part, contaminants.
1991-06-01
International Nuclear Information System (INIS)
A super-hydrophobic coating was prepared by combining a rigid base film with crater-like hemispherical holes and acicular nanoparticles. The acicular boehmite powder provides a high contact angle on the film surface. The rigid base film with crater-like hemispherical holes inhibits the rapid decrease of contact angle by surface rubbing. The combination of different roughness is an effective method for improving the abrasion resistance of super-hydrophobic films.
2009-04-15
PAGETOID RETICULOSIS IN A 5 YEAR OLD BOY
UK PubMed Central (United Kingdom)
We present a rare case of pagetoid reticulosis arising in a five year old white boy. He had a history of a large chronic erythematous, scaly patch on his left buttock that had shown intermittent...Full Text Available
2008-04-01
3D investigations of plasma erosion craters using FIB/SEM dual-beam techniques
Energy Technology Data Exchange (ETDEWEB)
Plasma erosion craters caused by electrical discharges on the surface of materials are important features of the erosion processes resulting in the degradation of electrodes. In the present work, electrical discharges were produced on a bi-metallic Ni/Cu multilayered surface. By means of dual beam techniques, coupling a focused ion beam (FIB) and a scanning electron microscope (SEM), not only the surface but also the sub-surface structure of the craters were investigated. Using the combination of SEM, FIB and STEM-EDX, a complete three-dimensional investigation of the craters were carried out. The analysis of the microstructure modifications as a function of depth enabled to determine the field of interaction between the plasma and the material. (orig.)
2006-09-15
THE DISAPPEARING NUTRITIONAL BIAS AGAINST CHINESE GIRLS
British Library Electronic Table of Contents (United Kingdom)
This paper investigates whether China has reached postnatal nutrient intake equality between boys and girls, despite an exceptionally high ratio of boys to girls at birth, after dramatic technological advances in prenatal sex determination, rapid increases in income, and improved educational opportunities for females. Dominance methods applied to data from the Chinese Health and Nutrition Surveys (selected years 1991-2004) reveal no bias in calorie consumption between girls and boys. We find some weak evidence of protein bias toward boys in 1991, but it disappeared by 2004. (JEL I32, O15, N35)
2011-01-01
Impact of Hight Velocity Cold Spray Particles
Energy Technology Data Exchange (ETDEWEB)
This paper presents experimental data and an computational model of the cold spray solid particle impact process. Copper particles impacting onto a polished stainless steel substrate are examined. The high velocity impact causes significant plastic deformation of both the particle and the sub- strate, but no melting is observed. The plastic deformation exposes clean surfaces that, under the high impact pressures, result in significant bond strengths between the particle and substrate. Experimental measurements of the splat and crater sizes compare well with the numerical calculations. It is shown that the crater depth is significant and increases with impact velocity. However, the splat diameter is much less sensitive to the impact velocity. It is also shown that the geometric lengths of the splat and crater scale linearly with the diameter of the impacting particle. It is hoped that the results presented will allow better ...
1998-12-01
Energy Technology Data Exchange (ETDEWEB)
This article describes the disenchantment with electric cars after considerable hype by industry. Also discussed is why electric cars have failed to catch on.
1995-04-01
Increased frequency of reproductive health problems among fathers of boys with hypospadias
British Library Electronic Table of Contents (United Kingdom)
BACKGROUNDSome studies have suggested an association between paternal subfertility and hypospadias among their sons, although the association has not been systematically investigated. We therefore compared male reproductive health among a group of fathers of boys with hypospadias and a group of fathers to normal children.METHODSA total of 64 fathers of boys with hypospadias participated; 349 partners of pregnant women served as a control group. All men delivered a semen sample, had a blood sample drawn, underwent a physical examination and completed a questionnaire.RESULTSFathers of boys with hypospadias had a significantly lower median sperm concentration (54.1 x 106/ml) (P = 0.004) and total sperm count (222.0 x 106) (P = 0.009) than the controls (81.2 and 326.0 x 106/ml). In addition, t...
2007-01-01
Purpose: The purpose of this paper is to show how Nigeria's current Universal Basic Education on primary schooling targets Muslim "Almajiri" street boys for basic literacy acquisition. The paper examines the policy's management implementation practices and challenges, as well as provides policy options that may minimize discrepancies for effective management. Design/methodology/approach: The discussion is guided by preliminary qualitative studies using phenomenology research philosophy to better understand the social realities of the boys' schooling. Using a descriptive case study approach, two schools in a major city of northern Nigeria served as research sites. Data collection process involved informal interviews, active observations, and discussions with a purpose with four boys, and two teachers as primary participants. Data analysis engaged the generation of themes from the transcribed interview and personal ...
2007-12-01
Y-type urethral duplication presented with perineal fistula in a boy
UK PubMed Central (United Kingdom)
Urethral duplication is a rare congenital anomaly of the lower urinary system and has varied presentation. According to the Effmann classification, type IIA2-Y urethral duplication is charcterized by...Full Text Available
FURTHER EVALUATION OF RESPONSE INTERRUPTION AND REDIRECTION AS TREATMENT FOR STEREOTYPY
UK PubMed Central (United Kingdom)
The effects of 2 forms of response interruption and redirection (RIRD)—motor RIRD and vocal RIRD—were examined with 4 boys with autism to evaluate further the effects of this intervention...Full Text Available
2011-01-01
Colon Mucinous Adenocarcinoma in Childhood: A Case Report with Emphasis on Image Findings
UK PubMed Central (United Kingdom)
Colorectal cancer is extremely rare in children. We report a case of a 12-year-old boy who presented with a five-month history of weight loss and anorexia, associated with vomiting episodes, dizziness,...Full Text Available
2010-01-01
Calcium Requirements and Metabolism in Chinese-American Boys and Girls
UK PubMed Central (United Kingdom)
Calcium requirements of North American adolescents were set at 1300 mg/day based on data from white girls. Calcium requirements for Asian-American adolescents have not been studied. Using metabolic...Full Text Available
2010-08-01
Annular subvalvular left ventricular aneurysm in Bahia, Brazil.
UK PubMed Central (United Kingdom)
Two cases of left ventricular aneurysm, a 16-year-old black boy and a 23-year-old white girl, from Bahia, Brazil, are presented. In both patients there was enlargement of the cardiac silhouette and...Full Text Available
1976-10-01
Characterization of polymer solar cells by TOF-SIMS depth profiling
Energy Technology Data Exchange (ETDEWEB)
Solar cells consisting of polymer layers sandwiched between a transparent electrode on glass and a metal top electrode are studied using dynamic time-of-flight secondary ion mass spectrometry (TOF-SIMS) in dual-beam mode. Because depth profiling of polymers and polymer-metal stacks is a relatively new field the craters were thoroughly investigated by environmental SEM (ESEM), interferometry, surface profilometry and tapping mode AFM. A huge increase in crater bottom roughness was observed when starting from the aluminum top layer going in depth, resulting in a loss of depth resolution. It is shown that layer-to-layer diffusion and contaminants at buried interfaces can be extracted from the depth profiles when taking into account the loss of depth resolution.
2003-01-15
"The focus of this study was to examine the structural, social, and attitudinal factors that influence an individual?s decision to choose an IT career. The findings revealed many differences among male and female high school students? attitudes and intentions. Although many stereotypes existed among the male and female students, perceptions appeared to be similar within the population. For boys, computer and technical skills had a stronger association with attitudes toward IT than for girls. For girls, social issues showed a strong association with attitudes toward IT. Overall, the intention to pursue IT as a career was most likely to prevail within the population of the high school boys."
2005-11-01
Focused Ion Beam Recovery of Hypervelocity Impact Residue in Experimental Craters on Metallic Foils.
Energy Technology Data Exchange (ETDEWEB)
The Stardust sample return capsule will return to Earth in January 2006 with primitive debris collected from Comet 81P/Wild-2 during the fly-by encounter in 2004. In addition to the cometary particles embedded in low-density silica aerogel, there will be microcraters preserved in the Al foils (1100 series; 100 {micro}m thick) that are wrapped around the sample tray assembly. Soda lime spheres ({approx}49 {micro}m in diameter) have been accelerated with a Light Gas Gun into flight-grade Al foils at 6.35 km s{sup -1} to simulate the capture of cometary debris. The experimental craters have been analyzed using scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDX) to locate and characterize remnants of the projectile material remaining within the craters. In addition, ion beam induced secondary electron imaging has proven particularly useful in identifying areas within the craters that contain ...
2005-11-04
Pseudocraters as indicators of ground ice on Mars
International Nuclear Information System (INIS)
Positive identification of Martian pseudocraters would be a strong indication of past occurrence of ice at or near the surface of Mars. The basis for suggesting that small cones on Mars are pseudocraters includes: (1) small size, (2) abundant but patchy distribution on what appear to be volcanic plains, (3) presence of other features suggestive of surface or subsurface ice, (4) morphological similarities to Icelandic pseudocraters, and (5) the similarity in distribution of crater/cone diameter ratios to Icelandic pseudocraters. This last morphometric parameter may be the most important, since other possible small terrestrial volcanic analogs have very different crater/cone diameter ratio distributions. In a survey of the available high resolution Viking Orbiter imagery, abundant fields of possible pseudocraters were found. However, only a small fraction of the plains forming units imaged at high resolution were found to contain the small cones. ...
1987-05-01
Energy Technology Data Exchange (ETDEWEB)
This paper explains how mine operators are taking a closer look at the power of explosives and how primary breakage affects other open-pit mining costs. Slurries have overcome most of the disadvantages attributed to them in their early years and may replace Anfo. Effective blasting is the key to an efficient, low-cost mining operation. Reviews are presented on research in crater studies, computer-aided design, the expanding gas theory, and high-speed motion picture cameras that show the importance of shock energy in fracturing the rock interfaces throughout the burden. The paper concludes with MSHA-approved courses in blasting offered throughout the US.
1982-07-01
UK PubMed Central (United Kingdom)
Tomato (Lycopersicon esculentum var. Better Boy) plants were transformed with a tomato leaf wound-inducible polygalacturonase (PG) β-subunit gene in the antisense orientation...Full Text Available
2003-10-01
Primary gonadal damage following treatment of brain tumors in childhood
Energy Technology Data Exchange (ETDEWEB)
Gonadal function was studied in two groups of children previously treated for medulloblastoma with surgery followed by postoperative craniospinal irradiation. In group 1 but not in group 2, the children also received adjuvant chemotherapy for one to two years. All children in group 1 received a nitrosourea (BCNU or CCNU), plus vincristine in four and procarbazine in three patients. The nine children in group 1 showed clinical and biochemical evidence of gonadal damage with elevated serum FSH concentrations and, in the boys, small testes for their stage of pubertal development. In group 2 (n . 8), each child had completed pubertal development normally, the boys had adult sized testes and the girls regular menses. Gonadotropin values were normal in all eight children. We conclude that nitrosoureas were responsible for the gonadal damage in the children in group 1, with procarbazine also contributing to the damage in the three children who ...
1983-10-01
Video and seismic observations of Strombolian eruptions at Erebus volcano, Antarctica
British Library Electronic Table of Contents (United Kingdom)
Between 1986 and 1990 the eruptive activity of Erebus volcano was monitored by a video camera with on-screen time code and recorded on video tape. Corresponding seismic and acoustic signals were recorded from a network of 6 geophones and 2 infrasonic microphones. Two hundred Strombolian explosions and three lava flows which were erupted from 7 vents were captured on video. In December 1986 the Strombolian eruptions ejected bombs and ash. In November 1987 large bubble-bursting Strombolian eruptions were observed. The bubbles burst when the bubble walls thinned to ?20?cm. Explosions with bomb flight-times up to 14.5?s were accompanied by seismic signals with our local size estimate, ?unified magnitudes?? (mu), up to 2.3. Explosions in pools of lava formed by flows in the Inner Crater were co...
2008-01-01
British Library Electronic Table of Contents (United Kingdom)
Intrusive degassing and recycling of degassed and dense magma at depth have been proposed for a long time at Stromboli. The brief explosive event that occurred at the summit craters on 9 January 2005 threw out bombs and lapilli that could be good candidates to illustrate recycling of shallow degassed magma at depth. We present an extensive data set on both the textures and the mineral, bulk rock and glassy matrix chemistry of the ?9 Jan? products. The latter have the common shoshonitic?basaltic bulk composition of lavas and scoriae issued from typical strombolian activity. In contrast they differ by the heterogeneous chemistry of their matrix glasses and their crystal textures that testify to crystal dissolution event(s) just prior magma crystallization upon ascent and eruption. Comparison...
2008-01-01
Rb-Sr ages and palaeomagnetic data for some Angolan alkaline intrusives
International Nuclear Information System (INIS)
New Rb-Sr age measurements are reported for a number of intrusives from Angola. Data for the Njoio and Tchivira nepheline syenite bodies yield mineral isochrons indicating ages of 104,3+-0,8 Ma and 130,8+-1,4 Ma respectively. Palaeomagnetic studies on the same occurrences gave marginal and scattered results respectively. Micas from the Camafuca crater-facies kimberlite yielded and apparent age of 1 822+-151 Ma, a result that is far in excess of the Tertiary (or younger) age inferred for this pipe. Similarly conflicting data were obtained for the Nova Lisboa kimberlite. It is likely that older crustal micas incorporated in the kimberlite breccias are responsible for the anomalous ages reported on the kimberlites. Satisfactory palaeomagnetic data are reported for the Zenza and Bailundu occurrences, not dated by the Rb-Sr method. A convenient K-Ar age of 80+-0,8 Ma was obtainable for Zenza.
Observation of dust stream formation produced by low current, high voltage cathode spots
International Nuclear Information System (INIS)
Macroparticle acceleration driven by low current, high voltage cathode spots has been investigated for potential applications ranging from micrometeoroid simulation to nanoparticle deposition/implantation. Acceleration by this process was observed to occur when nanometer and micrometer-sized particles were exposed to a high voltage pulse in the presence of a plasma discharge. The applied negative voltage pulse initiates the formation of multiple, high voltage, low current cathode spots which provide the mechanism of actual acceleration of the charged dust particles. Dust streams generated by this process were detected using laser scattering techniques. Cathode spot behavior was also documented. The particle impact craters observed at the surface of downstream witness badges were documented using scanning electron microscopy and light microscopy. The observed impacts suggest the presence of energetic macroparticles formed during this process.
2004-04-01
International Nuclear Information System (INIS)
DZ4 substrates were coated with NiCoCrAlY by plasma spray and subsequently treated by high current pulsed electron beams(HCPEB) of different parameters. The surface microstructure, phase structure and high temperature oxidation resistance were studied. It has been shown that as a result of the HCPEB treatment the loose and rough structure remelted and the surface became smooth. Smooth microregion, craters and cracks appeared on the surface. The ?' phase manifolded and there was no visible thermal stress. The oxidation test at 900 degree C for 100 h showed that a more compact and successive ?-Al_2O_3 scale was formed on the surface of the samples after HCPEB irradiation, which improved the oxidation resistance of the NiCoCrAlY coatings obviously. (authors)
2009-09-01
Energy Technology Data Exchange (ETDEWEB)
This report summarizes the results of Task 3 work that was initially discussed in our monthly reports for the period October 1, 1992 through September 30, 1993, and contained in our various papers and abstracts, both published and currently in press or in review. Our work during this period was involved (a) the continuation of studies begun prior to October, 1992, focussed mainly on aspects of the caldera geology, volcanic stratigraphy, magmatic activity, hydrothermal mineralization and extensional tectonics of the western and northwestern parts of the southwestern and Nevada volcanic field (SWNVF), studies of the subsurface rocks of Yucca Mountain utilizing drill hole samples obtained in 1991 and 1992, and (b) new studies of veins and siliceous rocks cropping out in northwestern Yucca Mountain that provide evidence for previously unrecognized hydrothermal activity during the Crater Flat Tuff period of volcanism.
1993-09-30
British Library Electronic Table of Contents (United Kingdom)
A combined numerical and theoretical study is conducted herein on the penetration of semi-infinite targets by jacketed rods with different r"j"0/r"c"0 ratios where r"j"0 and r"c"0 are the radii of the jacket and the core, respectively. The numerical results show that for smaller r"j"0/r"c"0 ratios the u-v relationship changes only a little compared to that of unitary long rod penetrator of the same core material, hence, the u-v relationship of unitary (homogeneous) long rod penetration is also applicable for jacketed rod penetration. Model for cratering in semi-infinite targets by jacketed rods is then suggested by using the laws of conversation of mass, momentum and energy, together with the u-v relationship of unitary (homogeneous) long rod penetration and an analytical model for predict...
2011-01-01
The Case for Universal Basic Education for the World's Poorest Boys and Girls
An estimated 110 million children between the ages of 6 and 11--60 percent of them girls--will not see the inside of a classroom this year, and another 150 million are likely to drop out before completing primary school. Yet this is a disease with a known cure. We know what tools are needed and what models are proven to work. We also know that the cost of that cure--perhaps $7.5 billion to $10 billion per year--is minuscule compared with the enormous benefits it will bring for health, economics, women's empowerment, and basic human dignity.
2005-11-01
School of Earth and Environment
...Verheggen, B; Dommen, J; Duplissy, J; Prevot, AS; Weingartner, E; Riipinen, I; Kulmala, M; Spracklen, DV; Carslaw, KS; ...Carslaw, KS; Boucher, O; Spracklen, DV; Mann, GW; Rae, JGL; Woodward, S; Kulmala, M (2010) A review of natural aerosol interactions ...Pickering, S; Ogren, JA; Andrews, E; Baltensperger, U; Weingartner, E; Boy, M; Kulmala, M; Laakso, L; Lihavainen, H; ...Fastrup, B; Gagne, S; Hahn, F; Harrison, RG; Kellett, B; Kirkby, J; Kulmala, M; Laakso, L; Laaksonen, A; ...
Diagnosis of peanut inhalation by MRI
International Nuclear Information System (INIS)
We describe a 16-month-old boy presenting with stridor and fever. The chest X-ray suggested inhalation of a foreign body but here was no history of this. A high spot a T_1-weighted chest MRI was due to a peanut which was seen to have moved from the right main bronchus to the left inferior bronchus, between the two MRI studies. MRI can provide information on position and size of the peanut, the conditons of the surrounding tissues and may be also useful in treatment. We consider MRI to be a valuable new method for the diagnosis of peanut inhalation. (orig./GDG).
1992-01-01
Dextranomer/hyaluronic acid copolymer (Deflux) implants mimicking distal ureteral calculi on CT
Energy Technology Data Exchange (ETDEWEB)
Periureteral or subtrigonal injection of dextranomer/hyaluronic acid (Dx/HA) copolymer (Deflux, Q-Med, Uppsala, Sweden) is an increasingly common endoscopic treatment for vesicoureteral reflux. We report a confusing radiographic finding of bilateral calcified Dx/HA injections initially thought to represent bilateral distal ureteral stones in a boy who presented with intermittent periumbilical pain. Urologists, radiologists, and emergency room physicians should be aware of the potential for calcification of ureteral implants of Dx/HA, and of the potentially confusing radiographic images that may result. (orig.)
2008-01-15
International Nuclear Information System (INIS)
A study was made investigate a relationship existing in the dentoskeletal framework and the soft tissue profile around the face, and compared the sexual differences between boys and girls having the normal occlusion in the mixed dentition. The lateral cephalograms were composed of 67 boys aged 10.3 years and 68 girls aged 10.4 years, respectively. By means of the lateral cephalograms, both the hard-and soft tissue structures were simultaneously analyzed, measured and evaluated by introducing the several reference items: S-N plane, palatal plane, mandibular plane, N-A line and A-P line for the dentoskeletal structures and N'-P' line for the soft tissue, and the 21 measuring points for the both structures. The significant findings were as follows: 1. In general the boys showed the larger nasal component dimension than did the girls, but the length and height of nose(N'-Prn and NA-Prn) showed the significant sexual difference ...
1978-11-01
Mineralogical Data of Shocked Quartz Materials from K/T Boundary and Impact Crater
Shocked quartz minerals from the Cretaceous-Tertiary (K/T) boundary and impact craters have been mainly discussed from distribution of optical directions, mean optical refractive index, and X-ray data (1). The purpose of the present study is presentation of the detailed mineralogical data of shocked quartz found in the K/T boundaries and terrestrial impact craters (2,3,4,5). X-ray powder diffraction pattern of shocked quartz aggregate reveals that all Xray peaks are split into major three peaks composed of low-density quartz (LQ), normal quartz (Q), and shocked quartz with high density (SQ). X-ray peaks of (110), (200), (201), (202), and (211) in the hexagonal cell are also split into many peaks. The X-ray intensity among LQ, Q, and SQ phases indicates that the SQ phase shows 36% to 53% in six K/T boundary samples (5). The relative X-ray intensity ratio of shocked quartz to standard rock crystal decreases into 13% to 37%, which suggests that ...
1992-07-01
Energy Technology Data Exchange (ETDEWEB)
Most households in low and middle income countries, including in India, use solid fuels (coal/coke/lignite, firewood, dung, and crop residue) for cooking and heating. Such fuels increase child mortality, chiefly from acute respiratory infection. There are, however, few direct estimates of the impact of solid fuel on child mortality in India. Methods: We compared household solid fuel use in 1998 between 6790 child deaths, from all causes, in the previous year and 609 601 living children living in 1.1 million nationally-representative homes in India. Analyses were stratified by child's gender, age (neonatal, post-neonatal, 1-4 years) and colder versus warmer states. We also examined the association of solid fuel to non-fatal pneumonias. Solid fuel use was very common (87% in households with child deaths and 77% in households with living children). After adjustment for demographic factors and living conditions, solid-fuel use significantly increase child deaths at ages 1-4 ...
2010-08-17
Energy Technology Data Exchange (ETDEWEB)
The prevalence of hepatic cysts is 0.1% to 0.5% based on autopsy studies, and 2.5% based on US examinations. Percutaneous therapies are a new alternative to surgery. They include simple percutaneous aspiration, catheter drainage alone, and catheter drainage with sclerotherapy. We present an 11-year-old boy admitted to hospital because of abdominal pain. A diagnosis of simple hepatic cyst was made, which was treated with aspiration and tetracycline hydrochloride solution (5%) injection into the cystic cavity. Complete regression was seen on US and MRI examination at 3 months, with total collapse and deflation of the cyst. The cyst regressed totally, leaving a hyperechoic linear scar on US examination at 1 year. On the basis of the clinical and imaging results obtained, percutaneous sclerotherapy of hepatic cysts can be recommended as the treatment of choice and as a valid alternative to laparoscopy in children. (orig.)
2009-10-15
Surgical management of osteoradionecrosis of the temporal bone
Energy Technology Data Exchange (ETDEWEB)
The surgical management of osteoradionecrosis of the temporal bone has met with limited success because of the difficulty in accurate assessment of the viability of nonnecrotic bone intraoperatively. Failure to resect all nonviable bone results in recurrence of a necrotic focus. With the use of hyperbaric oxygen therapy to stabilize marginal bone and oral tetracycline to label viable bone preoperatively, removal of all nonviable bone can be accomplished. Postoperatively, a second course of hyperbaric therapy enhances wound healing, thus assuring a successful outcome. This article details a successful systematic approach that was developed to resect a necrotic focus in the temporal bone of a 10-year-old boy who had undergone a full course of radiotherapy for treatment of a rhabdomyosarcoma.
1988-03-01
Students' general and physics epistemological beliefs: a twofold phenomenon
British Library Electronic Table of Contents (United Kingdom)
Background: Although research on epistemological beliefs has expanded over the past two decades, there are still some issues that need to be explored, such as whether epistemological beliefs are domain general or domain specific. Purpose: One of the purposes of this research was to determine if high school students' general epistemological beliefs were different from their epistemological beliefs in the domain of physics. Sample: The research was conducted with 15 grade nine students studying in an urban all-boys school. Their average age was 16. Their previous school experiences were traditional oriented. Design and methods: A case study design with qualitative methods was used for the research. Two questionnaires were developed and used in semi-structured interview protocols two times, w...
2011-01-01
Single Setting Bilateral Laparoscopic Orchiopexy for Bilateral Intra-Abdominal Testicles
British Library Electronic Table of Contents (United Kingdom)
Purpose The laparoscopic surgical approach to unilateral intra-abdominal testis has replaced the open approach at several large centers. There is considerable literature on experience with unilateral intra-abdominal testes but little on the management of bilateral intra-abdominal testes. We assessed the feasibility and safety of performing single setting bilateral laparoscopic orchiopexy in boys with bilateral intra-abdominal testes. Materials and Methods A single surgeon experience was reviewed. The surgical technique was similar in all cases and on each side, including infra-umbilical access, diagnostic evaluation, peritoneal mobilization lateral to the spermatic vessels and inferior to the vas deferens, gubernacular transection, and a decision for or against a Fowler-Stephens procedure ...
2008-01-01
Severe immune haemolytic anaemia due to ceftriaxone in a patient with congenital nephrotic syndrome
British Library Electronic Table of Contents (United Kingdom)
Abstract Aim:- To describe the first case of ceftriaxone-related haemolysis in a patient with congenital nephrotic syndrome (CNS). Background:- Severe haemolysis caused by an immune reaction to ceftriaxone has mostly been described in patients with underlying haematological or immune dysfunction. Case report:- The authors present a 20-month-old boy with CNS of the Finnish type with several previous severe infections treated with ceftriaxone, admitted for suspected sepsis. Following ceftriaxone administration he developed shock secondary to an acute haemolytic reaction, with severe anaemia. Hypersensitivity to ceftriaxone was documented through positive agglutination tests. Conclusion:- Onset of haemolysis following ceftriaxone administration, particularly in a patient previously exposed to...
2011-01-01
Radioexposure of children in cranial examinations with new-generation CT equipment
Energy Technology Data Exchange (ETDEWEB)
Using phantoms of children simulating a child of 6 months of age and another one aged 6 years, the authors measured the amount of radioexposure of the lens of the eye, the thyroid and of the gonads. The two computer tomographs Somatom SF and Tomoscan 300 under examination, produced radiodoses of comparable magnitudes. Both devices allow additional examination techniques of particularly high economy. It was found that in cranial CT the exposure of the lens to radiation is generally below 1 R if the orbitae are not situated in the plane of section. If a distance of 2-3 cm is maintained from the orbitae, the dose remains below 0.5 R. Protecting the gonads is meaningful in a 6-year-old boy, whereas covering-up of the thyroid reduced the dose only slightly.
1983-04-01
British Library Electronic Table of Contents (United Kingdom)
Objectives To present our preliminary experience with laparoscopic groin exploration and subsequent laparoscopic orchiectomy and internal ring closure for testicular nubbin in children and discuss the usefulness of our new treatment strategy. The advantages of laparoscopic orchiopexy for intra-abdominal testis are the ability to start treatment as soon as a diagnosis has been made and to permit minimally invasive surgery. These advantages can apply to laparoscopic orchiectomy for a testicular nubbin. Methods A total of 6 boys with a testicular nubbin (age range 14-76 months, mean age 27.3 months) underwent laparoscopic orchiectomy at our institution from June 2007 to June 2008. We opened the posterior parietal peritoneum by incising the peritoneum lateral to the spermatic vessel, distal to...
2009-01-01
British Library Electronic Table of Contents (United Kingdom)
Children with attention-deficit/hyperactivity disorder (ADHD) often have poor relationships with peers. However, research on this topic has predominantly focused on boys. This study considered child gender, ADHD status, and dimensionally assessed conduct problems as predictors of peer relationship difficulties. Participants were 125 children (ages 6-10; 67% male), 63 with clinical diagnoses of ADHD and 62 non-ADHD comparison youth. Conduct problems were reported by teachers and observed in a lab playgroup. Peer relationships were assessed by parent report, teacher report, and peer sociometric nominations in the playgroup. Results suggested that children with ADHD, as well as those with high conduct problems, displayed more impaired peer relationships than did comparison children and those ...
2011-01-01
Energy Technology Data Exchange (ETDEWEB)
The results of the CT investigation in children and teenagers up to 18, made in 1990-1994 were exposed to retrospective analysis: 2279 children were examined. The computer research proved the pathological changes in case 1205 people - 52%. In this group 58 children turned out to suffer from brain tumors. The most frequent tumor spatted was: astrocytoma (8), ependymoma (5), oligodendroglioma (3). The brain tumors happen to appear more often in case of boys (34) than in case of girls (22). (author) 6 refs, 2 figs, 2 tabs
1995-12-31
Mechanical properties and tribological behavior of TiN-CrAlN and CrN-CrAlN multilayer coatings
Energy Technology Data Exchange (ETDEWEB)
There is an increasing number of applications for hard coatings in engineering where the properties of the single-layer coating are not sufficient. One way to solve this problem is to use a multilayer coating that combines the properties of several coating materials. In this study, TiN-CrAlN and CrN-CrAlN multilayer coatings were deposited on 100Cr6 and S6-5-2 (DIN) steel substrates, by means of unbalanced magnetron sputtering. For comparison, TiN, CrN and CrAlN single-layer coatings were also prepared. For all depositions the coating temperature was below 473 K. Indentation testing, hardness measurements and scratch tests were performed to characterize the mechanical properties. The correlation between the wear behavior in rolling contact and the mechanical properties of the multilayer coatings is reported. A ball crater preparation technique through scratch tests and wear tracks was used to observe the deformation and fracture behavior occurring as a result of ...
1999-02-01
Energy Technology Data Exchange (ETDEWEB)
A C{sub 60} {sup +} primary ion source has been coupled to an ion microscope secondary ion mass spectrometry (SIMS) instrument to examine sputtering of silicon with an emphasis on possible application of C{sub 60} {sup +} depth profiling for high depth resolution SIMS analysis of silicon semiconductor materials. Unexpectedly, C{sub 60} {sup +} SIMS depth profiling of silicon was found to be complicated by the deposition of an amorphous carbon layer which buries the silicon substrate. Sputtering of the silicon was observed only at the highest accessible beam energies (14.5 keV impact) or by using oxygen backfilling. C{sub 60} {sup +} SIMS depth profiling of As delta-doped test samples at 14.5 keV demonstrated a substantial (factor of 5) degradation in depth resolution compared to Cs{sup +} SIMS depth profiling. This degradation is thought to result from the formation of an unusual platelet-like grain structure on the SIMS crater bottoms. Other unusual topographical ...
2006-07-30
Comparison of Mount Saint Helens volcanic eruption to a nuclear explosion. Technical note
Energy Technology Data Exchange (ETDEWEB)
The phenomena and effects of airblast, ground shock, thermal radiation, cratering and ejecta, and debris cloud and deposition from the eruption of Mt. St. Helens were compared to those that would result from a nuclear explosion to determine if phenomena or effects were analogous and thus might provide useful data for military nuclear weapon effects studies. It is concluded that the phenomena are not analogous. In particular, airblast destruction was caused by clouds of ash driven by subsonic winds, rather than by a supersonic shock wave that would be the damage mechanism of a nuclear explosion. Because of the lack of analogy between the eruption and nuclear explosion phenomena, it appears questionable that any of the effects are analogous; therefore, it is unlikely that anything more of military interest can be gained from studying the effects of the eruption. However, key contacts for further information on the eruption and the associated research studies are ...
1981-01-01
Characterisation of thin films on rough steel substrates by FTIR microscopy and imaging
International Nuclear Information System (INIS)
Complete text of publication follows. According to the new European regulations (Restrictions of Hazardous Substance Directive), there is an emerging demand for environmental friendly metal treatments instead on formerly used chromate conversion coating technique. The aim of the present investigations was to characterise and compare silicon containing protective thin layers on roughened galvanized steel surfaces (with average roughness of 0.7 microns), using FTIR microscopy and imaging techniques. The silicon containing coatings were produced either by Chemical Vapour Deposition (CVD) or by wet chemical treatment using liquid silane. FTIR techniques offer new possibilities in the characterisations and chemical mapping of differently coated thin films, besides SEM+EDS, AFM, nanoindentation, XPS measurements (P. Nemeth et al., Materials Science Forum, 589 (2008) 433-438). All measurements were carried out by a Varian FTS-7000 spectrometer with a 'Stingray' microscope configuration ...
The radiological accident in Tammiku
International Nuclear Information System (INIS)
On 21 October 1994, three brothers entered a waste repository at Tammiku, Estonia, without authorization and removed a metal container enclosing a caesium-137 source. During the removal the source was dislodged and fell to the ground. One of the men picked up the source, placed it in his pocket and took it to his home in the nearby village of Kiisa. Very soon after entry into the repository he began to feel ill, and few hours later he began to vomit. The man was subsequently admitted to hospital with severe injuries to his leg and hip and died on 2 November 1994. The injury and subsequent death were not attributed to radiation exposure, and the source remained in the man's house with his wife and stepson and the boy's great-grandmother. The boy was hospitalized on 17 November with severe burns on his hands, and these were identified by a doctor as radiation induced. The authorities were alerted, and the Estonian Rescue Board recovered the ...
Energy Technology Data Exchange (ETDEWEB)
Two children with cutaneous lymphoma and leukemia who were treated with total skin electron beam therapy (TSEB) are described here. Patient 1. A 7-year-old boy was admitted because of a mass over the bilateral parotis and anemia. The white blood cell count on admission was 5,000/ul. Bone marrow examination revealed 70 per cent monoblasts (M5a type by FAB classification). Complete remission was obtained following the regimen of daunomycin, cytosine arabinoside, 6-mercaptopurine and prednisolone. He was again admitted because of a skin nodule on the left thigh 19 months after initial diagnosis. A biopsy of the skin nodule demonstrated monoblastic infiltration. He received 20 Grays (Gy) to the left thigh and this led to resolution of the skin nodule. At that time, other skin nodules appeared on the right upper and lower extremities. He was treated with TSEB. Daily doses of 1 Gy were given twice a week with a 4 MeV electron beam and a total dose of 10 Gy was ...
1988-07-01
Use of sodium chromate Cr/sub 51/ in diagnosing childhood idiopathic pulmonary hemosiderosis
Energy Technology Data Exchange (ETDEWEB)
The diagnosis of idiopathic pulmonary hemosiderosis (IPH) may be elusive. A 6-year-old boy had microcytic hypochromic anemia and a hemolytic component. Hemosiderin-laden macrophages were not found in the gastric aspirate. He had no pulmonary signs or symptoms. Extensive hematologic and roentgenologic investigations failed to reveal the cause of the anemia. Quantitative serial scintigraphic scanning showed significant (35%) pulmonary sequestration of autologous erythrocytes labeled with sodium chromate Cr51. The half-life of the RBCs was moderately decreased (half-life, 15 days; normal, 25 to 35 days). An open-lung biopsy spece Cr51. The half-life of the RBCs was moderately decreased (half-life, 15 days; normal, 25 to 35 days). An open-lung biopsy specimen confirmed the diagnosis of IPH. A diagnosis of IPH should be considered when children have iron deficiency anemia and pulmonary signs or symptoms. Organ sequestration studies may be helpful in equivocal cases.
1984-08-01
Energy Technology Data Exchange (ETDEWEB)
Sprengel deformity is a congential malformation with usually unilateral elevation and medial rotation of the scapula. An omovertebral bone is generally present. Associated skeletal malformations are frequently present. Though functional impairment is mild, the cosmetic and psycho-social impairment can be considerable. The prognosis of early surgical therapy is good. The presented case also justifies surgical correction in the older child. (orig.) [German] Die Sprengel-Deformitaet ist eine angeborene Fehlbildung mit meist einseitiger Elevation und Medialrotation der Skapula. Meist ist ein Os omovertebrale vorhanden. Assoziierte skelettale Fehlbildungen sind haeufig. Obgleich funktionell wenig einschraenkend, ist die kosmetische und psycho-soziale Beeintraechtigung oft erheblich. Die Prognose der fruehen operativen Therapie ist gut. Der vorliegende Fall ermutigt zur operativen Therapie auch im hoeheren Kindesalter. (orig.)
2003-02-01
International Nuclear Information System (INIS)
Intrathecal _1_9_8Au colloid and methotrexate were administered to 27 children (between 1972 and 1981) with non-lymphatic leukaemia, 21 with non-Hodgkin lymphoma and two with Ewing's sarcoma to prevent CNS involvement. In one boy with non-lymphatic leukaemia a stable remission after a three-year period of cytostatic treatment ended with isolated CNS involvement. No isolated CNS recurrence occurred in children with non-Hodgkin lymphoma receiving regular radiogold administration. Combined iris and CNS recurrence occurred in one child with non-Hodkin lymphoma. Eleven of 21 children with non-Hodgkin lymphoma have been in complete initial remission for 4-39 months without cytostatic treatment. Late cerebral complications have not been observed after _1_9_8Au colloid and methotrexate. (orig.).
Pre-operative MRI of anorectal anomalies in the newborn period
Energy Technology Data Exchange (ETDEWEB)
Nine infants (six boys, three girls) with anorectal anomalies were examined in the immediate newborn period, prior to corrective surgery, with MRI. Three high, one intermediate and five low anomalies were found at MRI - one patient with a `low` lesion was subsequently found at surgery 2 months later to have a high anorectal anomaly. This infant had passed meconium per urethram soon after the MRI study, prompting the need for a protective colostomy and stressing the importance of a thorough clinical examination of babies with anorectal malformations. The MRI results and findings at surgery were in agreement in all other patients (n=8). Hydronephrosis was evident in two and renal agenesis in one patient. Sacrococcygeal hypoplasia was found in two and two hemivertebrae in one infant. No spinal cord lesion was identified. One fistula was evident on MRI but four were later found at surgery. Uniformly hyperintense T1 signal meconium was seen in all nine newborns, ...
1995-11-01
Energy Technology Data Exchange (ETDEWEB)
We report a patient who developed occlusion of the intracranial major arteries induced by radiation therapy for craniopharyngioma. The patient, a 9-year-old boy, presented with deterioration of vision, nausea and vomiting. He underwent a right ventriculo-peritoneal shunt operation, and the tumor was partially removed. Postoperatively, he received focal radiation therapy with total of 60 Gy. Preoperative cerebral angiography, cerebral vessels had no sigh of occlusive lesion or stenosis. One year after irradiation, he started to have repeated cerebral ischemic attacks. But no regrowth of the tumor was detected on CT scans. Two years and 8 months after irradiation, he suddenly had right hemiparesis. Cerebral angiography revealed severe stenosis of the right anterior cerebral artery (precommunicating segment), middle cerebral artery (horizontal portion) and terminal portion of the right carotid artery. Left carotid angiography showed complete occlusion of the terminal ...
1994-10-01
International Nuclear Information System (INIS)
We report a patient who developed occlusion of the intracranial major arteries induced by radiation therapy for craniopharyngioma. The patient, a 9-year-old boy, presented with deterioration of vision, nausea and vomiting. He underwent a right ventriculo-peritoneal shunt operation, and the tumor was partially removed. Postoperatively, he received focal radiation therapy with total of 60 Gy. Preoperative cerebral angiography, cerebral vessels had no sigh of occlusive lesion or stenosis. One year after irradiation, he started to have repeated cerebral ischemic attacks. But no regrowth of the tumor was detected on CT scans. Two years and 8 months after irradiation, he suddenly had right hemiparesis. Cerebral angiography revealed severe stenosis of the right anterior cerebral artery (precommunicating segment), middle cerebral artery (horizontal portion) and terminal portion of the right carotid artery. Left carotid angiography showed complete occlusion of the terminal ...
1994-01-01
International Nuclear Information System (INIS)
We investigated the isotropic diffusion coefficient (D') and fractional anisotropy (FA) in white matter (WM) during brain development, using an optimised diffusion-tensor imaging (DTI) method with whole brain coverage in a clinically acceptable time. We images 52 children with no evident neurological abnormality (30 boys, 22 girls aged 1 day-16 years) using high-angle DTI with optimised temporal gradient performance. D' and FA were calculated in 10 regions of interest in white matter. We saw that the age-related reduction in D' and increase in FA follow a mono- or biexponential model in white matter, probably depending on the compactness and myelination rate of the fibre tracts. In contrast to other areas, in which adult values were reached during the third year, there is a trend to continuous increase in FA in all deep white-matter areas, suggesting continuing maturation and organisation of deep tracts not detected on conventional MRI. (orig.)
2004-04-01
British Library Electronic Table of Contents (United Kingdom)
We analyzed the clinical features of inpatients at a Japanese pediatric department who were infected with pandemic (H1N1) 2009 virus. Study participants included 46 children hospitalized from July 2009 to January 2010. Infection with the virus was confirmed using real-time reverse transcriptase polymerase chain reaction (RT-PCR). The epidemic month was October 2009; 34 patients were boys, and median age was 7?years. Pandemic influenza-associated respiratory diseases included pneumonia (n?=?42), bronchitis (n?=?3), and pharyngitis (n?=?1). The median time from onset to admission was 3?days. Children were divided into those with severe (n?=?32) versus nonsevere illnesses (n?=?14) according to Japanese guidelines. Significant features in the severe group were younger age, previous asthmatic a...
2011-01-01
Aggressive Ewing's sarcoma appearing as a cold lesion on bone scan
International Nuclear Information System (INIS)
Ewing's sarcoma classically presents as a hot spot on bone scan as a result of increased vascularity of the tumor and new bone formation. Purpose We report and analyze an uncommon pattern of a 'cold' lesion in Ewing's sarcoma on bone scan and its pathophysiologic significance. Case report A 15-year-old boy complaining of thigh pain. CT scan evoked Ewing's sarcoma or osteitis. MRI evoked chronic osteitis. Scintigraphy showed a fairly intense and heterogeneous uptake on the femoral lesion and no abnormal uptake elsewhere. Biopsy showed none pathologic pattern. Three months later, a second biopsy concluded to Ewing's sarcoma. Bone scan showed a larger lesion with peripheral intense uptake centered by enlarged 'cold' area in the left femoral diaphysis and no evident bone metastasis. The patient underwent chemotherapy and surgery. Three months later, bone scan showed extensive skeletal metastasis. Conclusion Ewing's sarcoma appears usually as an intense lesion on bone ...
2009-10-01
Energy Technology Data Exchange (ETDEWEB)
''Hair-on-end'' skull changes resembling thalassemia were rarely described in the 1950s and 1960s in children with cyanotic congenital heart diseases; these changes were described almost entirely in patients with tetralogy of Fallot or D-transposition of the great arteries. As these lesions have become correctable, the osseous changes, never common, seem now only to exist in a small number of patients with uncorrectable complex cyanotic congenital heart disease who survive in a chronic hypoxic state. We present two cases: a case of marked marrow expansion in the skull of a 5-year-old boy with uncorrectable cyanotic heart disease studied by CT, and a second case of an 8-year-old with tetralogy of Fallot and pulmonary atresia studied by plain skull radiographs. The true incidence of these findings is unknown. (orig.)
2005-07-01
Optically stimulated luminescence (OSL) study of synthetic stishovite
International Nuclear Information System (INIS)
Optically stimulated luminescence (OSL) of synthetic stishovite was investigated for a future dating technique of meteor impact craters. Luminescence around 330 nm was measured on the #gamma#-ray irradiated stishovite under two stimulating light sources of infrared laser (830 nm) and blue light emitting diode set (470 nm). Thermoluminescence (TL) studies before and after the OSL measurements showed the intensities around 100-200 deg. C and 220-350 deg. C to increase and those around 350-450 deg. C to decrease. This indicates that a part of deep-trapped charges excited during the OSL measurements were retrapped by shallower traps. The infrared stimulated luminescence (IRSL) after the TL measurement up to 450 deg. C could not be detected, while the blue light stimulated luminescence (BLSL) after TL had about one-tenth of the intensity before TL. This indicates that a part of the charges in shallower traps were detrapped thermally and returned to the deeper traps ...
2000-12-15
Most common bacterial species causing peritonitis in the course of peritoneal dialysis (PDP) are coagulase-negative staphylococci, Staphylococcus aureus and streptococci. Haemophilus influenzae is rarely associated with PDP. Hereby we present the first known case of APD-associated peritonitis caused by non-type able H. influenzae (NTHi) presenting the beta-lactamase negative, ampicillin-resistant (BLNAR) phenotype. An 18 year old boy who had been treated with the APD for 12 months due to SLE was admitted in good general condition with diagnosis of PDP. Standard diagnostic and therapeutical procedures were initiated. Dialysis fluid was turbid with cytosis of 435 WBC/ml. From dialysis fluid pure culture of Gram-negative coccobacillus was isolated. The isolate was identified as a BLNAR phenotype. The same bacterium was isolated from nasal swab. Blood cultures were negative. After evaluation of antimicrobial susceptibility the treatment was changed for the oral ...
2009-04-01
Laparoscopic classification and treatment of the impalpable testis.
Laparoscopic orchiopexy has gained popularity in recent years. However, the decision when to perform one-stage laparoscopic orchiopexy without division of the spermatic vessels versus initial ligation of the spermatic vessels followed later by orchiopexy is not clear. A new laparoscopic classification to facilitate decision-making during laparoscopy, according to the position of the impalpable testis and the relation of the spermatic vessels and vas deferens to the internal ring, with a management protocol based on this classification is presented. Over a 2-year period, a total of 37 boys with 52 impalpable gonads underwent a laparoscopic procedure. Four laparoscopic types of testis were noted: type I: no testis visualized; type II: a testis seen at the internal ring with the vas and vessels looping to the internal ring; type III: testis at the internal ring, with vas and vessels going to the testis directly; and type IV: intra-abdominal testis not related to the ...
1999-01-01
Effect of lead exposure in children
International Nuclear Information System (INIS)
Increasing prosperity and population-growth in many developing countries are resulting in accelerated growth in population of vehicles and vehicle-kilometers traveled. In Pakistan also, the number of vehicles has jumped from 0.8 million to about 4.0 million within 20 years, showing an overall increase of more than 400%. Accordingly, the consumption of petrol (motor spirit) has increased from 828,670 metric tons to 1,189,042 metric tons. The high content of lead in petrol is a serious issue, as the end- product is the release of lead into the environment. In Pakistan, prior to July 2001, lead-content in petrol was reported to be as high as 0.35-0.84 gram per liter. The reported lead-levels in air (micrograms/cubic centimeter) in different cities of Pakistan are: Karachi (1980-81) 0.13-0.24; Peshawar (1994-95) 0.21-0.79; Lahore (1993-94) 0.15-8.36 and (1999-2000) 0.89-7.85 and Rawalpindi (1999-2000) 0.71-10.00, indicating the very alarming increase and high levels of lead in the ambient ...
Development of regional cerebral blood flow during childhood studied with Iodine-123-IMP SPECT
International Nuclear Information System (INIS)
Regional cerebral blood flow (rCBF) was assessed with single photon emission computed tomography (SPECT), "1"2"3I-N-isopropyl-iodoamphetamine ("1"2"3I-IMP), and the Table-Look-Up method in 51 children (27 boys, 24 girls) considered neurologically normal and aged 1 month to 15 years (mean age, 4 years 1 month; standard deviation (SD) 3 years 11 months) divided into seven age groups. The rCBF was measured in cortical regions, the cerebellum, thalamus, and the head of the caudate nucleus. Curves for reference values and standard deviations were defined for each region. The rCBF rapidly increased until 2 years of age, reaching maximum values during the third to fifth periods (2 to 10 years of age) in each region. The rCBFs then decreased, reaching adult levels at 10 to 15 years of age. The rCBF reached maximum values later in the frontal region than in other regions. The rCBF during the early period increased most prominently in the occipital region. These results ...
2006-06-01
In 2002 and again in 2003, an investigative journalist unit at ABC News transported a 6.8 kilogram metallic slug of depleted uranium (DU) via shipping container from Istanbul, Turkey to Brooklyn, NY and from Jakarta, Indonesia to Long Beach, CA. Targeted inspection of these shipping containers by Department of Homeland Security (DHS) personnel, included the use of gamma-ray imaging, portal monitors and hand-held radiation detectors, did not uncover the hidden DU. Monte Carlo analysis of the gamma-ray intensity and spectrum of a DU slug and one consisting of highly-enriched uranium (HEU) showed that DU was a proper surrogate for testing the ability of DHS to detect the illicit transport of HEU. Our analysis using MCNP-5 illustrated the ease of fully shielding an HEU sample to avoid detection. The assembly of an Improvised Nuclear Device (IND) -- a crude atomic bomb -- from sub-critical pieces of HEU metal was then examined via Monte Carlo criticality calculations. Nuclear explosive ...
2007-04-01
Energy Technology Data Exchange (ETDEWEB)
In nuclear fuel, in approximately one quarter of the fissions, one of the two formed fission products is gaseous. These are mainly the noble gases xenon and krypton with isotopes of xenon contributing up to 90% of the product gases. These noble fission gases do not combine with other species, and have a low solubility in the normally used uranium oxide matrix. They can be dissolved in the fuel matrix or precipitate in nanometer-sized bubbles within the fuel grain, in micrometer-sized bubbles at the grain boundaries, and a fraction also precipitates in fuel pores, coming from fuel fabrication. A fraction of the gas can also be released into the plenum of the fuel rod. With increasing fission, and therefore burn-up, the ceramic fuel material experiences a transformation of its structure in the 'cooler' rim region of the fuel. A subdivision occurs of the original fuel grains of few microns size into thousands of small grains of sub-micron sizes. Additionally, larger ...
2008-07-01
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