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Sample records for multiple-locus variable-nucleotide tandem

  1. Multiple-locus variable-number tandem-repeat analysis of pathogenic Yersinia enterocolitica in China.

    Xin Wang

    Full Text Available The predominant bioserotypes of pathogenic Yersinia enterocolitica in China are 2/O: 9 and 3/O: 3; no pathogenic O: 8 strains have been found to date. Multiple-Locus Variable-Number Tandem-Repeat Analysis (MLVA based on seven loci was able to distinguish 104 genotypes among 218 pathogenic Y. enterocolitica isolates in China and from abroad, showing a high resolution. The major pathogenic serogroups in China, O: 3 and O: 9, were divided into two clusters based on MLVA genotyping. The different distribution of Y. enterocolitica MLVA genotypes maybe due to the recent dissemination of specific clones of 2/O: 9 and 3/O: 3 strains in China. MLVA was a helpful tool for bacterial pathogen surveillance and investigation of pathogenic Y. enterocolitica outbreaks.

  2. Imported brucellosis in Denmark: Molecular identification and multiple-locus variable number tandem repeat analysis (MLVA) genotyping of the bacteria

    Aftab, H.; Dargis, R.; Christensen, J. J.

    2011-01-01

    A polymerase chain reaction was used to identify Brucella species isolated from humans in Denmark. Consecutive analysis of referred bacteria and re-examination of historical isolates identified all as Brucella melitensis. Multiple-locus variable number tandem repeat analysis (MLVA) placed...... the isolates in the previously defined 'East Mediterranean' B. melitensis group....

  3. Characterization of Dutch Staphylococcus aureus from bovine mastitis using a Multiple Locus Variable Number Tandem Repeat Analysis

    Ikawaty, R.; Brouwer, E.C.; Jansen, M.D.; Duijkeren, van E.; Mevius, D.J.; Verhoef, J.; Fluit, A.C.

    2009-01-01

    Current typing methods for Staphylococcus aureus have important drawbacks. We evaluated a Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) scheme with 6 loci which lacks most drawbacks on 85 bovine mastitis isolates from The Netherlands. For each locus the number of repeat units (RU) was

  4. MULTIPLE-LOCUS VARIABLE-NUMBER TANDEM REPEAT ANALYSIS OF BRUCELLA ISOLATES FROM THAILAND.

    Kumkrong, Khurawan; Chankate, Phanita; Tonyoung, Wittawat; Intarapuk, Apiradee; Kerdsin, Anusak; Kalambaheti, Thareerat

    2017-01-01

    Brucellosis-induced abortion can result in significant economic loss to farm animals. Brucellosis can be transmitted to humans during slaughter of infected animals or via consumption of contaminated food products. Strain identification of Brucella isolates can reveal the route of transmission. Brucella strains were isolated from vaginal swabs of farm animal, cow milk and from human blood cultures. Multiplex PCR was used to identify Brucella species, and owing to high DNA homology among Brucella isolates, multiple-locus variable-number tandem repeat analysis (MLVA) based on the number of tandem repeats at 16 different genomic loci was used for strain identification. Multiplex PCR categorized the isolates into B. abortus (n = 7), B. melitensis (n = 37), B. suis (n = 3), and 5 of unknown Brucella spp. MLVA-16 clustering analysis differentiated the strains into various genotypes, with Brucella isolates from the same geographic region being closely related, and revealed that the Thai isolates were phylogenetically distinct from those in other countries, including within the Southeast Asian region. Thus, MLVA-16 typing has utility in epidemiological studies.

  5. A novel multiple locus variable number of tandem repeat (VNTR) analysis (MLVA) method for Propionibacterium acnes.

    Hauck, Yolande; Soler, Charles; Gérôme, Patrick; Vong, Rithy; Macnab, Christine; Appere, Géraldine; Vergnaud, Gilles; Pourcel, Christine

    2015-07-01

    Propionibacterium acnes plays a central role in the pathogenesis of acne and is responsible for severe opportunistic infections. Numerous typing schemes have been developed that allow the identification of phylotypes, but they are often insufficient to differentiate subtypes. To better understand the genetic diversity of this species and to perform epidemiological analyses, high throughput discriminant genotyping techniques are needed. Here we describe the development of a multiple locus variable number of tandem repeats (VNTR) analysis (MLVA) method. Thirteen VNTRs were identified in the genome of P. acnes and were used to genotype a collection of clinical isolates. In addition, publically available sequencing data for 102 genomes were analyzed in silico, providing an MLVA genotype. The clustering of MLVA data was in perfect congruence with whole genome based clustering. Analysis of the clustered regularly interspaced short palindromic repeat (CRISPR) element uncovered new spacers, a supplementary source of genotypic information. The present MLVA13 scheme and associated internet database represents a first line genotyping assay to investigate large number of isolates. Particular strains may then be submitted to full genome sequencing in order to better analyze their pathogenic potential. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Multiple-locus variable-number tandem repeat analysis for molecular typing of Aspergillus fumigatus

    Chermette René

    2010-12-01

    Full Text Available Abstract Background Multiple-locus variable-number tandem repeat (VNTR analysis (MLVA is a prominent subtyping method to resolve closely related microbial isolates to provide information for establishing genetic patterns among isolates and to investigate disease outbreaks. The usefulness of MLVA was recently demonstrated for the avian major pathogen Chlamydophila psittaci. In the present study, we developed a similar method for another pathogen of birds: the filamentous fungus Aspergillus fumigatus. Results We selected 10 VNTR markers located on 4 different chromosomes (1, 5, 6 and 8 of A. fumigatus. These markers were tested with 57 unrelated isolates from different hosts or their environment (53 isolates from avian species in France, China or Morocco, 3 isolates from humans collected at CHU Henri Mondor hospital in France and the reference strain CBS 144.89. The Simpson index for individual markers ranged from 0.5771 to 0.8530. A combined loci index calculated with all the markers yielded an index of 0.9994. In a second step, the panel of 10 markers was used in different epidemiological situations and tested on 277 isolates, including 62 isolates from birds in Guangxi province in China, 95 isolates collected in two duck farms in France and 120 environmental isolates from a turkey hatchery in France. A database was created with the results of the present study http://minisatellites.u-psud.fr/MLVAnet/. Three major clusters of isolates were defined by using the graphing algorithm termed Minimum Spanning Tree (MST. The first cluster comprised most of the avian isolates collected in the two duck farms in France, the second cluster comprised most of the avian isolates collected in poultry farms in China and the third one comprised most of the isolates collected in the turkey hatchery in France. Conclusions MLVA displayed excellent discriminatory power. The method showed a good reproducibility. MST analysis revealed an interesting clustering with a

  7. Multiple-locus variable-number tandem repeat analysis of Neisseria meningitidis yields groupings similar to those obtained by multilocus sequence typing.

    Schouls, Leo M; Ende, Arie van der; Damen, Marjolein; Pol, Ingrid van de

    2006-01-01

    We identified many variable-number tandem repeat (VNTR) loci in the genomes of Neisseria meningitidis serogroups A, B, and C and utilized a number of these loci to develop a multiple-locus variable-number tandem repeat analysis (MLVA). Eighty-five N. meningitidis serogroup B and C isolates obtained

  8. Use of multiple-locus variable-number tandem-repeats analysis (MLVA) typing to characterize Salmonella Typhimurium DT41 broiler breeder infections

    Litrup, E.; Christensen, H.; Nordentoft, Steen

    2010-01-01

    To characterize isolates of Salmonella Typhimurium DT41 obtained from infected flocks of broiler breeders by multiple-locus variable-number tandem-repeats analysis (MLVA) and compare results with a diverse strain collection from Germany and United Kingdom and isolates from Danish patients. A total...

  9. Development and validation of a single-tube multiple-locus variable number tandem repeat analysis for Klebsiella pneumoniae.

    Antoinette A T P Brink

    Full Text Available Genotyping of Klebsiella pneumoniae is indispensable for management of nosocomial infections, monitoring of emerging strains--including extended-spectrum beta-lactamase (ESBL producers-, and general epidemiology. Such objectives require a high-resolution genotyping method with a fixed scheme that allows (1 long-term retrospective and prospective assessment, (2 objective result readout and (3 library storage for database development and exchangeable results. We have developed a multiple-locus variable number tandem repeat analysis (MLVA using a single-tube fluorescently primed multiplex PCR for 8 Variable Number Tandem Repeats (VNTRs and automated fragment size analysis. The type allocation scheme was optimized using 224 K. pneumoniae clinical isolates, which yielded 101 MLVA types. The method was compared to the gold standard multilocus sequence typing (MLST using a subset of these clinical isolates (n = 95 and found to be highly concordant, with at least as high a resolution but with considerably less hands-on time. Our results position this MLVA scheme as an appropriate, high-throughput and relatively low-cost tool for K. pneumoniae epidemiology.

  10. Genotyping of Bacillus anthracis strains based on automated capillary 25-loci Multiple Locus Variable-Number Tandem Repeats Analysis

    Ciervo Alessandra

    2006-04-01

    Full Text Available Abstract Background The genome of Bacillus anthracis, the etiological agent of anthrax, is highly monomorphic which makes differentiation between strains difficult. A Multiple Locus Variable-number tandem repeats (VNTR Analysis (MLVA assay based on 20 markers was previously described. It has considerable discrimination power, reproducibility, and low cost, especially since the markers proposed can be typed by agarose-gel electrophoresis. However in an emergency situation, faster genotyping and access to representative databases is necessary. Results Genotyping of B. anthracis reference strains and isolates from France and Italy was done using a 25 loci MLVA assay combining 21 previously described loci and 4 new ones. DNA was amplified in 4 multiplex PCR reactions and the length of the resulting 25 amplicons was estimated by automated capillary electrophoresis. The results were reproducible and the data were consistent with other gel based methods once differences in mobility patterns were taken into account. Some alleles previously unresolved by agarose gel electrophoresis could be resolved by capillary electrophoresis, thus further increasing the assay resolution. One particular locus, Bams30, is the result of a recombination between a 27 bp tandem repeat and a 9 bp tandem repeat. The analysis of the array illustrates the evolution process of tandem repeats. Conclusion In a crisis situation of suspected bioterrorism, standardization, speed and accuracy, together with the availability of reference typing data are important issues, as illustrated by the 2001 anthrax letters event. In this report we describe an upgrade of the previously published MLVA method for genotyping of B. anthracis and apply the method to the typing of French and Italian B. anthracis strain collections. The increased number of markers studied compared to reports using only 8 loci greatly improves the discrimination power of the technique. An Italian strain belonging to the

  11. Longitudinal survey of Staphylococcus aureus in cystic fibrosis patients using a multiple-locus variable-number of tandem-repeats analysis method

    Vergnaud Gilles; Moissenet Didier; Corvol Harriet; Fauroux Brigitte; Corbineau Gaëlle; Hormigos Katia; Vu-Thien Hoang; Pourcel Christine

    2010-01-01

    Abstract Background Staphylococcus aureus infection in patients with cystic fibrosis (CF) is frequent and may be due to colonization by a few pathogenic lineages. Systematic genotyping of all isolates, methicillin-susceptible S. aureus (MSSA) as well as methicillin-resistant S. aureus (MRSA) is necessary to identify such lineages and follow their evolution in patients. Multiple-locus variable-number tandem repeat analysis (MLVA/VNTR) was used to survey S. aureus clinical isolates in a French ...

  12. Identification of Variable-Number Tandem-Repeat (VNTR) Sequences in Legionella pneumophila and Development of an Optimized Multiple-Locus VNTR Analysis Typing Scheme▿

    Pourcel, Christine; Visca, Paolo; Afshar, Baharak; D'Arezzo, Silvia; Vergnaud, Gilles; Fry, Norman K.

    2007-01-01

    The utility of a genotypic typing assay for Legionella pneumophila was investigated. A multiple-locus variable number of tandem repeats (VNTR) analysis (MLVA) scheme using PCR and agarose gel electrophoresis is proposed based on eight minisatellite markers. Panels of well-characterized strains were examined in a multicenter analysis to validate the assay and to compare its performance to that of other genotyping assays. Excellent typeability, reproducibility, stability, and epidemiological concordance were observed. The MLVA type or profile is composed of a string of allele numbers, corresponding to the number of repeats at each VNTR locus, separated by commas, in a predetermined order. A database containing information from 99 L. pneumophila serogroup 1 strains and four strains of other serogroups and their MLVA profiles, which can be queried online, is available from http://bacterial-genotyping.igmors.u-psud.fr/. PMID:17251393

  13. A multiple-locus variable-number tandem repeat analysis (MLVA) of Listeria monocytogenes isolated from Norwegian salmon-processing factories and from listeriosis patients.

    Lunestad, B T; Truong, T T T; Lindstedt, B-A

    2013-10-01

    The objective of this study was to characterize Listeria monocytogenes isolated from farmed Atlantic salmon (Salmo salar) and the processing environment in three different Norwegian factories, and compare these to clinical isolates by multiple-locus variable-number tandem repeat analysis (MLVA). The 65 L. monocytogenes isolates obtained gave 15 distinct MLVA profiles. There was great heterogeneity in the distribution of MLVA profiles in factories and within each factory. Nine of the 15 MLVA profiles found in the fish-associated isolates were found to match human profiles. The MLVA profile 07-07-09-10-06 was the most common strain in Norwegian listeriosis patients. L. monocytogenes with this profile has previously been associated with at least two known listeriosis outbreaks in Norway, neither determined to be due to fish consumption. However, since this profile was also found in fish and in the processing environment, fish should be considered as a possible food vehicle during sporadic cases and outbreaks of listeriosis.

  14. Identification of Variable-Number Tandem-Repeat (VNTR) Sequences in Acinetobacter pittii and Development of an Optimized Multiple-Locus VNTR Analysis Typing Scheme.

    Hu, Yuan; Li, Bo Qing; Jin, Da Zhi; He, Li Hua; Tao, Xiao Xia; Zhang, Jian Zhong

    2015-12-01

    To develop a multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) assay for Acinetobacter pittii typing. Polymorphic VNTRs were searched by Tandem Repeats Finder. The distribution and polymorphism of each VNTR locus were analyzed in all the A. pittii genomes deposited in the NCBI genome database by BLAST and were evaluated with a collection of 20 well-characterized clinical A. pittii strains and one reference strain. The MLVA assay was compared with pulsed-field gel electrophoresis (PFGE) for discriminating A. pittii isolates. Ten VNTR loci were identified upon bioinformatic screening of A. pittii genomes, but only five of them showed full amplifiability and good polymorphism. Therefore, an MLVA assay composed of five VNTR loci was developed. The typeability, reproducibility, stability, discriminatory power, and epidemiological concordance were excellent. Compared with PFGE, the new optimized MLVA typing scheme provided the same and even greater discrimination. Compared with PFGE, MLVA typing is a faster and more standardized alternative for studying the genetic relatedness of A. pittii isolates in disease surveillance and outbreak investigation. Copyright © 2015 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  15. Genetic diversity of Neisseria meningitidis serogroup C ST-4821 in China based on multiple-locus variable number tandem repeat analysis.

    Xiaoying Shan

    Full Text Available Neisseria meningitidis sequence type (ST-4821 was first reported in China in 2003, and a new hyper-virulent lineage has been designated as the ST-4821 complex. A large number of N. meningitidis ST-4821 strains have been identified in China since 2003; however, the microevolution characteristics of this complex are unclear. Different combinations of variable number of tandem repeats (VNTR loci were used in multiple-locus VNTR analysis (MLVA to analyze 118 N. meningitidis serogroup C ST-4821 strains isolated from seventeen provinces between 2003 and 2012. Additionally, MLVA with five VNTR loci was performed due to its high discriminatory power. One hundred and eighteen isolates were found to comprise 112 subtypes based on MLVA, and 16 outbreak-associated strains were clustered into one group. These data indicate a high level of diversity for N. meningitidis ST-4821 due to microevolution in the last decade. In addition, the results revealed high similarity between isolates from the same geographic origins, which is helpful when monitoring the spread of N. meningitidis serogroup C ST-4821 and will provide valuable information for the control and prevention of bacterial meningitis in China.

  16. Identification of Variable-Number Tandem-Repeat (VNTR) Sequences in Acinetobacter baumannii and Interlaboratory Validation of an Optimized Multiple-Locus VNTR Analysis Typing Scheme▿†

    Pourcel, Christine; Minandri, Fabrizia; Hauck, Yolande; D'Arezzo, Silvia; Imperi, Francesco; Vergnaud, Gilles; Visca, Paolo

    2011-01-01

    Acinetobacter baumannii is an important opportunistic pathogen responsible for nosocomial outbreaks, mostly occurring in intensive care units. Due to the multiplicity of infection sources, reliable molecular fingerprinting techniques are needed to establish epidemiological correlations among A. baumannii isolates. Multiple-locus variable-number tandem-repeat analysis (MLVA) has proven to be a fast, reliable, and cost-effective typing method for several bacterial species. In this study, an MLVA assay compatible with simple PCR- and agarose gel-based electrophoresis steps as well as with high-throughput automated methods was developed for A. baumannii typing. Preliminarily, 10 potential polymorphic variable-number tandem repeats (VNTRs) were identified upon bioinformatic screening of six annotated genome sequences of A. baumannii. A collection of 7 reference strains plus 18 well-characterized isolates, including unique types and representatives of the three international A. baumannii lineages, was then evaluated in a two-center study aimed at validating the MLVA assay and comparing it with other genotyping assays, namely, macrorestriction analysis with pulsed-field gel electrophoresis (PFGE) and PCR-based sequence group (SG) profiling. The results showed that MLVA can discriminate between isolates with identical PFGE types and SG profiles. A panel of eight VNTR markers was selected, all showing the ability to be amplified and good amounts of polymorphism in the majority of strains. Independently generated MLVA profiles, composed of an ordered string of allele numbers corresponding to the number of repeats at each VNTR locus, were concordant between centers. Typeability, reproducibility, stability, discriminatory power, and epidemiological concordance were excellent. A database containing information and MLVA profiles for several A. baumannii strains is available from http://mlva.u-psud.fr/. PMID:21147956

  17. Multiple-locus variable-number tandem repeat analysis of Leptospira interrogans and Leptospira borgpetersenii isolated from small feral and wild mammals in East Asia.

    Koizumi, Nobuo; Izumiya, Hidemasa; Mu, Jung-Jung; Arent, Zbigniew; Okano, Shou; Nakajima, Chie; Suzuki, Yasuhiko; Mizutani Muto, Maki; Tanikawa, Tsutomu; Taylor, Kyle R; Komatsu, Noriyuki; Yoshimatsu, Kumiko; Thi Thu Ha, Hoang; Ohnishi, Makoto

    2015-12-01

    Leptospira spp. are the causative agents of a worldwide zoonosis, leptospirosis, maintained by various mammals. Each Leptospira serovar is frequently associated with a particular maintenance host, and recently, Leptospira genotype-host association has also been suggested to limit serovars to restricted areas. We investigated the molecular characteristics of L. interrogans and L. borgpetersenii which were isolated from small feral and wild animals in four East Asian states using multiple-locus variable-number tandem repeat analysis (MLVA). MLVA using 11 loci was performed on 110 L. interrogans serogroups from Japan (79 strains of 5 serogroups from 3 animal species), Philippines (21; 3; 2), Taiwan (7; 2; 3), and Vietnam (3; 1; 1). A MLVA method using 4 loci for L. borgpetersenii was established and performed on 52 isolates from Japan (26; 3; 7), Philippines (13; 1; 2), and Taiwan (13; 1; 3). In L. interrogans, serogroups Autumnalis and Hebdomadis appeared more genetically diverse than serogroups Bataviae, Grippotyphosa, Icterohaemorrhagiae, Pomona, or Pyrogenes. The former serogroup strains with the exception of one Hebdomadis strain were isolated from Apodemus speciosus while all the latter serogroup strains with the exception of Grippotyphosa were isolated from Rattus norvegicus. L. borgpetersenii was isolated from at least 11 animal species while L. interrogans was isolated from five species, which might suggest a wider host range for L. borgpetersenii. Broad host preference in a single genotype was also observed, which colonized not only different species of the same genera but also multiple animal genera. This study demonstrates that there may be variability in the range of genetic diversity among different Leptospira serogroups, which may be attributed to maintenance host animals and environmental factors. Copyright © 2015. Published by Elsevier B.V.

  18. Multiple-locus variable number of tandem repeats fingerprinting (MLVF) and virulence factor analysis of methicillin resistant Staphylococcus aureus SCCmec type III.

    Emaneini, Mohammad; Jabalameli, Leila; Iman-Eini, Hossein; Aligholi, Marzieh; Ghasemi, Amir; Nakhjavani, Farrokh Akbari; Taherikalani, Morovat; Khoramian, Babak; Asadollahi, Parisa; Jabalameli, Fereshteh

    2011-01-01

    Methicillin resistant Staphylococcus aureus (MRSA), particularly strains with type III staphylococcal cassette chromosome mec (SCCmec), represent a serious human pathogen in Tehran, Iran. The disease-causing capability depends on their ability to produce a wide variety of virulent factors. The prevalence of exotoxin genes and multiple-locus variable number of tandem repeats fingerprinting (MLVF) profile among MRSA isolates, from patients in Tehran, was evaluated by PCR and Multiplex-PCR. The MLVF typing of 144 MRSA isolates with type III SCCmec produced 5 different MLVF types. Generally, 97.2% (140/144) of all the isolates were positive for at least one of the tested exotoxin genes. The most prevalent genes were hld, found in 87.5% (126/144) of the isolates followed by lukE-lukD and hla found in 72.9% (105/144) and 70.1% (101/144) of the isolates, respectively. The tst gene, belonging to MLVF types I, IV and V, was found among three of the isolates from blood and wound samples. The sea gene was detected in 58.3% (84/144) of the isolates and the sed and see genes were found in one isolate with MLVF type V. The coexistence of genes was observed in the 87.5% (126/144) of the isolates. The rate of coexistence of hld with lukE-lukD, hla with lukE-lukD and sea with lukE-lukD were 66.7% (96/144), 44.4% (64/144) and 44.4% (64/144), respectively. The present study demonstrated that MRSA strains with type III SCCmec show different MLVF patterns and exotoxin profiles.

  19. Comparison of the capillary and agarose electrophoresis based multiple locus VNTR (variable number of tandem repeats) analysis (MLVA) on Mycobacterium bovis isolates.

    Jenkins, A O; Venter, E H; Hutamo, K; Godfroid, J

    2010-09-28

    Electrophoretic techniques that can be used for genotyping of bacterial pathogens ranges from manual, low-cost, agarose gels to high-throughput capillary electrophoresis sequencing machines. These two methods are currently employed in the electrophoresis of PCR products used in multiple locus VNTR (variable number of tandem repeats) analysis (MLVA), i.e. the agarose electrophoresis (AE) and the capillary electrophoresis (CE). Some authors have suggested that clusters generated by AE are less reliable than those generated by CE and that the latter is a more sensitive technique than the former when typing Mycobacterium tuberculosis complex (MTC) isolates. Because such a claim could have significant consequences for investigators in this field, a comparison was made on 19 Belgian Mycobacterium bovis strains which had previously been genotyped using CE VNTR analysis. The VNTR profiles of the CE VNTR analysis were compared with those obtained by AE VNTR analysis at 14 VNTR loci. Our results indicated that there were no differences in copy numbers at all loci tested when the copy numbers obtained by the AE VNTR analysis were compared with those obtained by CE VNTR analysis. The use of AE VNTR analysis in mycobacterial genotyping does not alter the sensitivity of the MLVA technique compared with the CE VNTR analysis. The AE VNTR can therefore be regarded as a viable alternative in moderately equipped laboratories that cannot afford the expensive equipment required for CE VNTR analysis and data obtained by AE VNTR analysis can be shared between laboratories which use the CE VNTR method. (c) 2010 Elsevier B.V. All rights reserved.

  20. Large Diversity of Porcine Yersinia enterocolitica 4/O:3 in Eight European Countries Assessed by Multiple-Locus Variable-Number Tandem-Repeat Analysis.

    Alakurtti, Sini; Keto-Timonen, Riikka; Virtanen, Sonja; Martínez, Pilar Ortiz; Laukkanen-Ninios, Riikka; Korkeala, Hannu

    2016-06-01

    A total of 253 multiple-locus variable-number tandem-repeat analysis (MLVA) types among 634 isolates were discovered while studying the genetic diversity of porcine Yersinia enterocolitica 4/O:3 isolates from eight different European countries. Six variable-number tandem-repeat (VNTR) loci V2A, V4, V5, V6, V7, and V9 were used to study the isolates from 82 farms in Belgium (n = 93, 7 farms), England (n = 41, 8 farms), Estonia (n = 106, 12 farms), Finland (n = 70, 13 farms), Italy (n = 111, 20 farms), Latvia (n = 66, 3 farms), Russia (n = 60, 10 farms), and Spain (n = 87, 9 farms). Cluster analysis revealed mainly country-specific clusters, and only one MLVA type consisting of two isolates was found from two countries: Russia and Italy. Also, farm-specific clusters were discovered, but same MLVA types could also be found from different farms. Analysis of multiple isolates originating either from the same tonsils (n = 4) or from the same farm, but 6 months apart, revealed both identical and different MLVA types. MLVA showed a very good discriminatory ability with a Simpson's discriminatory index (DI) of 0.989. DIs for VNTR loci V2A, V4, V5, V6, V7, and V9 were 0.916, 0.791, 0.901, 0.877, 0.912, and 0.785, respectively, when studying all isolates together, but variation was evident between isolates originating from different countries. Locus V4 in the Spanish isolates and locus V9 in the Latvian isolates did not differentiate (DI 0.000), and locus V9 in the English isolates showed very low discriminatory power (DI 0.049). The porcine Y. enterocolitica 4/O:3 isolates were diverse, but the variation in DI demonstrates that the well discriminating loci V2A, V5, V6, and V7 should be included in MLVA protocol when maximal discriminatory power is needed.

  1. Prevalence, antimicrobial resistance and multiple-locus variable-number tandem-repeat analysis profiles of diarrheagenic Escherichia coli isolated from different retail foods.

    Wang, Lili; Nakamura, Hiromi; Kage-Nakadai, Eriko; Hara-Kudo, Yukiko; Nishikawa, Yoshikazu

    2017-05-16

    Diarrheagenic E. coli (DEC) isolates were recovered from local retail markets and the Osaka Municipal Central Wholesale Market in Japan. Retail food samples were collected for analysis in Osaka Japan from 2005 to 2008 and consisted of 32 beef, 28 pork, 20 poultry, 136 fish, 66 fruits and vegetables and 51 ready-to-eat (RTE) food samples. A total of 82 DEC strains were recovered from 64 (19%) food samples with the highest prevalence in poultry (100%, 20/20), followed by pork (54%, 15/28), beef (28%, 9/32), fruits and vegetables (12%, 8/66), fish (6.6%, 9/136) and RTE foods (5.9%, 3/51). Most of the strains belonged to E. coli possessing the enteroaggregative E. coli (EAEC) heat-stable enterotoxin 1 (EAST1) gene (EAST1EC; n=62, P3 antimicrobial agents. Isolates resistant to >5 antimicrobials were only found in the meat samples, while isolates from the fruits and vegetables as well as RTE foods showed resistance to only 1 or 2 antimicrobial agents. Sixty one percent of EAST1EC, 56% of EPEC and all of the EAEC and ETEC were resistant to at least 1 antimicrobial agent. Multiple-locus variable-number tandem repeat analysis (MLVA) was used in this study for genotyping of DEC. The 82 isolates collected for this study showed 77 distinct MLVA profiles located among 3 branches. The Simpson's Index of Diversity (D) was 99.9% at its highest. The high diversity of these food strains would suggest their originating from a variety of sources and environments. In conclusion, retail food samples in Japan were contaminated with DEC; EAST1EC, a putative DEC, were detected at high rates in poultry, pork and beef. Isolates resistant to >3 antimicrobials were found only in raw meat and fish. Food animals may act as the reservoir for multi-resistant bacteria. Due to the finding that nearly 1/3 of EAST1EC strains were resistant to >3 antimicrobials, additional surveillance for EAST1EC should be initiated. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Improving resolution of public health surveillance for human Salmonella enterica serovar Typhimurium infection: 3 years of prospective multiple-locus variable-number tandem-repeat analysis (MLVA

    Sintchenko Vitali

    2012-03-01

    Full Text Available Abstract Background Prospective typing of Salmonella enterica serovar Typhimurium (STM by multiple-locus variable-number tandem-repeat analysis (MLVA can assist in identifying clusters of STM cases that might otherwise have gone unrecognised, as well as sources of sporadic and outbreak cases. This paper describes the dynamics of human STM infection in a prospective study of STM MLVA typing for public health surveillance. Methods During a three-year period between August 2007 and September 2010 all confirmed STM isolates were fingerprinted using MLVA as part of the New South Wales (NSW state public health surveillance program. Results A total of 4,920 STM isolates were typed and a subset of 4,377 human isolates was included in the analysis. The STM spectrum was dominated by a small number of phage types, including DT170 (44.6% of all isolates, DT135 (13.9%, DT9 (10.8%, DT44 (4.5% and DT126 (4.5%. There was a difference in the discriminatory power of MLVA types within endemic phage types: Simpson's index of diversity ranged from 0.109 and 0.113 for DTs 9 and 135 to 0.172 and 0.269 for DTs 170 and 44, respectively. 66 distinct STM clusters were observed ranging in size from 5 to 180 cases and in duration from 4 weeks to 25 weeks. 43 clusters had novel MLVA types and 23 represented recurrences of previously recorded MLVA types. The diversity of the STM population remained relatively constant over time. The gradual increase in the number of STM cases during the study was not related to significant changes in the number of clusters or their size. 667 different MLVA types or patterns were observed. Conclusions Prospective MLVA typing of STM allows the detection of community outbreaks and demonstrates the sustained level of STM diversity that accompanies the increasing incidence of human STM infections. The monitoring of novel and persistent MLVA types offers a new benchmark for STM surveillance. A part of this study was presented at the MEEGID

  3. Multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) and antibacterial resistance profiles of extended spectrum beta lactamase (ESBL) producing Pseudomonas aeruginosa among burnt patients in Tehran.

    Jabalameli, Fereshteh; Mirsalehian, Akbar; Sotoudeh, Nazli; Jabalameli, Leila; Aligholi, Marzieh; Khoramian, Babak; Taherikalani, Morovat; Emaneini, Mohammad

    2011-11-01

    Extended spectrum β-lactamase (ESBL)-producing trait was present in 48 out of the 112 (42.8%) Pseudomonas aeruginosa isolates collected from burn wound infections during a 12-month period. The presence of oxa-10, per-1, veb-1 and ges genes and the multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) of 112 P. aeruginosa strains were determined by PCR and multiplex PCR. Disk diffusion methods were used to determine the susceptibility of the isolates to antimicrobial agents as instructed by CLSI. All ESBL isolates were resistant to aztreonam, cefepime, cefotaxime, cefpodoxime, ceftazidime, ceftriaxone and ofloxacin. Fewer than 60% of ESBL isolates were resistant to imipenem, meropenem, and piperacillin-tazobactam but more than 90% were resistant to amikacin, ciprofloxacin, levofloxacin, ticarcillin and tobramycin. The most prevalent ESBL genes included oxa-10 (70%) and per-1 (50%) followed by veb-1 (31.3%). The gene encodes GES enzyme did not detect in any isolates. A total of 100 P. aeruginosa strains were typed by MLVF typing method. MLVF produced 42 different DNA banding patterns. These data indicate that different MLVF types infect burn wounds in patients at a hospital in Tehran and also suggest an alarming rate of ESBL-producing isolates in this test location. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

  4. DNA fingerprinting of Shiga-toxin producing Escherichia coli O157 based on Multiple-Locus Variable-Number Tandem-Repeats Analysis (MLVA

    Vardund Traute

    2003-12-01

    Full Text Available Abstract Background The ability to react early to possible outbreaks of Escherichia coli O157:H7 and to trace possible sources relies on the availability of highly discriminatory and reliable techniques. The development of methods that are fast and has the potential for complete automation is needed for this important pathogen. Methods In all 73 isolates of shiga-toxin producing E. coli O157 (STEC were used in this study. The two available fully sequenced STEC genomes were scanned for tandem repeated stretches of DNA, which were evaluated as polymorphic markers for isolate identification. Results The 73 E. coli isolates displayed 47 distinct patterns and the MLVA assay was capable of high discrimination between the E. coli O157 strains. The assay was fast and all the steps can be automated. Conclusion The findings demonstrate a novel high discriminatory molecular typing method for the important pathogen E. coli O157 that is fast, robust and offers many advantages compared to current methods.

  5. Genotyping analysis of Helicobacter pylori using multiple-locus variable-number tandem-repeats analysis in five regions of China and Japan

    Zhang Jinyong

    2011-09-01

    Full Text Available Abstract Background H. pylori (Helicobacter pylori is the major causative agent of chronic active gastritis. The population of H. pylori shows a high genomic variability among isolates. And the polymorphism of repeat-units of genomics had participated the important process of evolution. Its long term colonization of the stomach caused different clinical outcomes, which may relate to the high degree of genetic variation of H. pylori. A variety of molecular typing tools have been developed to access genetic relatedness in H. pylori isolates. However, there is still no standard genotyping system of this bacterium. The MLVA (Multi-locus of variable number of tandem repeat analysis method is useful for performing phylogenetic analysis and is widely used in bacteria genotyping; however, there's little application in H. pylori analysis. This article is the first application of the MLVA method to investigate H. pylori from different districts and ethnic groups of China. Results MLVA of 12 VNTR loci with high discrimination power based on 30 candidates were performed on a collection of 202 strains of H. pylori which originated from five regions of China and Japan. Phylogenetic tree was constructed using MLVA profiles. 12 VNTR loci presented with high various polymorphisms, and the results demonstrated very close relationships between genotypes and ethnic groups. Conclusions This study used MLVA methodology providing a new perspective on the ethnic groups and distribution characteristics of H. pylori.

  6. Typing and Evaluation of the Genetic Relatedness of Listeria monocytogenes Strains Isolated from Food Samples by the Multiple-Locus Variable number Tandem Repeat Analysis (MLVA

    Behrooz Sadeghi kalani

    2014-12-01

    Full Text Available Background and Aim:Listeria monocytogenes cause listeriosis and fatal infections in humans. The aim of this study was typing and evaluation of the genetic relatedness of L. monocytogenes strains from food samples using MLVA technique. Materials and Methods: 317 food samples were collected from 2009 to 2013 in Tehran,Iran. After final diagnosis of L. monocytogenes DNA was extracted to perform of MLVA technique, and also PCR products were analyzed by Gene Tools software. The number of tandem repeats was determined by using special equation for each selected locus. Also typing of strains was done. Results: 24 samples of 317 food samples were positive for L. monocytogenes using standard laboratory techniques. A total 13 different types were determined by MLVA technique that type 2 and type 3 were the most abundant types by 6 and 4 strains, respectively. Conclusions: The results of this study showed the presence of L. monocytogenes in dairy products and meat samples, therefore all people, especially pregnant women should observe health tips when using these products. The results of typing showed that L. monocytogenes strains from different sources can have the same origin. MLVA technique is easy with high accuracy and this method can be used in typing and evaluation of the genetic relatedness of L. monocytogenes for determination the source of contamination.

  7. Staphylococcus aureus from 152 cases of bovine, ovine and caprine mastitis investigated by Multiple-locus variable number of tandem repeat analysis (MLVA).

    Bergonier, Dominique; Sobral, Daniel; Feßler, Andrea T; Jacquet, Eric; Gilbert, Florence B; Schwarz, Stefan; Treilles, Michaël; Bouloc, Philippe; Pourcel, Christine; Vergnaud, Gilles

    2014-10-02

    Staphylococcus aureus is one of the main etiological agents of mastitis in ruminants. In the present retrospective study, we evaluated the potential interest of a previously described automated multiple loci Variable Number of Tandem Repeats (VNTR) Assay (MLVA) comprising 16 loci as a first line tool to investigate the population structure of S. aureus from mastitis. We determined the genetic diversity of S. aureus strains from cases of clinical and subclinical mastitis in dairy cattle (n = 118, of which 16 were methicillin-resistant), sheep (n = 18) and goats (n = 16). The 152 strains could be subdivided into 115 MLVA genotypes (including 14 genotypes for the ovine strains and 15 genotypes for the caprine strains). This corresponds to a discriminatory index (D) value of 0.9936. Comparison with published MLVA data obtained using the same protocol applied to strains from diverse human and animal origins revealed a low number (8.5%) of human-related MLVA genotypes among the present collection. Eighteen percent of the S. aureus mastitis collection belonged to clonal complexes apparently not associated with other pathological conditions. Some of them displayed a relatively low level of diversity in agreement with a restricted ecological niche. These findings provide arguments suggesting that specific S. aureus lineages particularly adapted to ruminant mammary glands have emerged and that MLVA is a convenient tool to provide a broad overview of the population, owing to the availability via internet of databases compiling published MLVA genotypes.

  8. DEVELOPMENT OF A MULTIPLE-LOCUS VARIABLE NUMBER OF TANDEM REPEAT ANALYSIS (MLVA FOR HELICOBACTER PYLORI AND ITS APPLICATION TO HELICOBACTER PYLORI ISOLATES FROM ROSTOV REGION,RUSSIA

    Sorokin VM

    2012-09-01

    Full Text Available Stomach infection with Helicobacter pylori (H. pylori is the second most common infectious disease of humans. The severe pathological consequences of this infection include gastric and duodenal ulcer disease, the development of gastric mucosal atrophy, gastric carcinoma, and, more rarely, malignant tumors of the lymphoma. H. pylori infections cause very high morbidity and mortality and are of particular concern in developing countries, where H. pylori prevalences as high as 90% have been reported. The population of H. pylori shows a high genomic variability among isolates. And the polymorphism of repeat-units of genomics had participated the important process of evolution. A variety of molecular typing tools have been developed to access genetic relatedness in H. pylori isolates. However, there is still no standard genotyping system of this bacterium. The MLVA (Multi-Locus of Variable number of tandem repeat Analysis method is useful for performing phylogenetic analysis and is widely used in bacteria genotyping; however, there's little application in H. pylori analysis. This article is the first application of the MLVA method to investigate H. pylori isolates in Russia. MLVA of 4 VNTR loci with high discrimination power based on 10 candidates were performed on a collection of 22 strains of H. pylori which originated from Rostov region of Russia. This method provides a starting point on which improvements to the method and comparisons to other techniques can be made.

  9. Use of multiple-locus variable-number of tandem repeats analysis (MLVA) to investigate genetic diversity of Salmonella enterica subsp. enterica serovar Typhimurium isolates from human, food, and veterinary sources

    Mateva, Gergana; Pedersen, Karl; Sørensen, Gitte

    2017-01-01

    -locus variable-number of tandem repeats analysis (MLVA) and compared results with antimicrobial resistance (AMR) determinations for 100 S. Typhimurium strains isolated in Bulgaria during 2008-2012 (50 veterinary/food and 50 human isolates). Results showed that isolates were divided into 80 and 34 groups using......). No clustering of isolates related to susceptibility/resistance to antimicrobials, source of isolation, or year of isolation was observed. Some MLVA types were found in both human and veterinary/food isolates, indicating a possible route of transmission. A majority (83%) of the isolates were found...

  10. TANDEM

    Federal Laboratory Consortium — The Tandem Van de Graaff facility provides researchers with beams of more than 40 different types of ions - atoms that have been stripped of their electrons. One of...

  11. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the period 7/1/00 to 10/30/00

    Dr. Paul Keim

    2000-11-07

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens.

  12. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the period 7/1/00 to 10/30/00

    Dr. Paul Keim

    2000-01-01

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens

  13. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the Period 4/1/00 to 6/30/00

    Dr. Paul Keim

    2000-11-07

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens.

  14. Multiple-Locus VNTR Analysis (MLVA) for Bacterial Strain Identification - Quarterly Progress Report for the Period 4/1/00 to 6/30/00

    Dr. Paul Keim

    2000-01-01

    Multiple locus VNTR analysis (MLVA) systems are being developed for B. anthracis, Y. pestis and F. tularensis. These are high resolution DNA fingerprinting systems that will allow for molecular epidemiology and forensic analysis of these pathogens

  15. Development and comparison of a generic multiple-locus variable-number tandem repeat analysis with PFGE for typing of Salmonella entericasubsp. enterica

    Kjeldsen, Marianne Kirstine; Torpdahl, Mia; Pedersen, Karl

    2015-01-01

    serovars can be typed. We developed a MLVA scheme for high discriminatory typing of Salmonella. Methods and Results Sixty-six unique VNTRs were investigated and the polymorphisms of seven promising VNTRs were evaluated with a panel 163 diverse isolates of 14 serotypes of significance for human health. Five......-related strains. Conclusions The technique showed a high discriminatory power within most serotypes comparable with or better than that of PFGE. Significance and impact of the Study This MLVA assay makes it possible to use a single typing method for Salmonella surveillance and outbreak investigations. This allows...... inexpensive and fast surveillance for laboratories without resources for both serotyping and molecular typing, e.g. PFGE or sequence-based methods, and thereby improve the effectiveness of epidemiological investigations of Salmonella infections globally....

  16. Multiple Locus Variable-Number Tandem-Repeat and Single-Nucleotide Polymorphism-Based Brucella Typing Reveals Multiple Lineages in Brucella melitensis Currently Endemic in China

    Mingjun Sun

    2017-12-01

    Full Text Available Brucellosis is a worldwide zoonotic disease caused by Brucella spp. In China, brucellosis is recognized as a reemerging disease mainly caused by Brucella melitensis specie. To better understand the currently endemic B. melitensis strains in China, three Brucella genotyping methods were applied to 110 B. melitensis strains obtained in past several years. By MLVA genotyping, five MLVA-8 genotypes were identified, among which genotypes 42 (1-5-3-13-2-2-3-2 was recognized as the predominant genotype, while genotype 63 (1-5-3-13-2-3-3-2 and a novel genotype of 1-5-3-13-2-4-3-2 were second frequently observed. MLVA-16 discerned a total of 57 MLVA-16 genotypes among these Brucella strains, with 41 genotypes being firstly detected and the other 16 genotypes being previously reported. By BruMLSA21 typing, six sequence types (STs were identified, among them ST8 is the most frequently seen in China while the other five STs were firstly detected and designated as ST137, ST138, ST139, ST140, and ST141 by international multilocus sequence typing database. Whole-genome sequence (WGS-single-nucleotide polymorphism (SNP-based typing and phylogenetic analysis resolved Chinese B. melitensis strains into five clusters, reflecting the existence of multiple lineages among these Chinese B. melitensis strains. In phylogeny, Chinese lineages are more closely related to strains collected from East Mediterranean and Middle East countries, such as Turkey, Kuwait, and Iraq. In the next few years, MLVA typing will certainly remain an important epidemiological tool for Brucella infection analysis, as it displays a high discriminatory ability and achieves result largely in agreement with WGS-SNP-based typing. However, WGS-SNP-based typing is found to be the most powerful and reliable method in discerning Brucella strains and will be popular used in the future.

  17. Use of multiple-locus variable-number of tandem repeats analysis (MLVA) to investigate genetic diversity of Salmonella enterica subsp. enterica serovar Typhimurium isolates from human, food, and veterinary sources

    Mateva, Gergana; Pedersen, Karl; Sørensen, Gitte

    2017-01-01

    MLVA and AMR, respectively. Simpson's index of diversity was determined to 0.994 ± 0.003 and 0.945 ± 0.012. The most frequently encountered MLVA profiles were 3-11-9-NA-211 (n = 5); 3-12-9-NA-211 (n = 3); 3-12-11-21-311 (n = 3); 3-17-10-NA-311 (n = 3); 2-20-9-7-212 (n = 3); and 2-23-NA-NA-111 (n = 3...

  18. Application of Molecular Typing Results in Source Attribution Models: The Case of Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) of Salmonella Isolates Obtained from Integrated Surveillance in Denmark

    de Knegt, Leonardo; Pires, Sara Monteiro; Löfström, Charlotta

    2016-01-01

    , and antibiotic resistance profiles for the Salmonella source attribution, and assess the utility of the results for the food safety decisionmakers. Full and simplified MLVA schemes from surveillance data were tested, and model fit and consistency of results were assessed using statistical measures. We conclude...

  19. Tandem repeat regions within the Burkholderia pseudomallei genome and their application for high resolution genotyping

    Harvey Steven P

    2007-03-01

    Full Text Available Abstract Background The facultative, intracellular bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a serious infectious disease of humans and animals. We identified and categorized tandem repeat arrays and their distribution throughout the genome of B. pseudomallei strain K96243 in order to develop a genetic typing method for B. pseudomallei. We then screened 104 of the potentially polymorphic loci across a diverse panel of 31 isolates including B. pseudomallei, B. mallei and B. thailandensis in order to identify loci with varying degrees of polymorphism. A subset of these tandem repeat arrays were subsequently developed into a multiple-locus VNTR analysis to examine 66 B. pseudomallei and 21 B. mallei isolates from around the world, as well as 95 lineages from a serial transfer experiment encompassing ~18,000 generations. Results B. pseudomallei contains a preponderance of tandem repeat loci throughout its genome, many of which are duplicated elsewhere in the genome. The majority of these loci are composed of repeat motif lengths of 6 to 9 bp with 4 to 10 repeat units and are predominately located in intergenic regions of the genome. Across geographically diverse B. pseudomallei and B.mallei isolates, the 32 VNTR loci displayed between 7 and 28 alleles, with Nei's diversity values ranging from 0.47 and 0.94. Mutation rates for these loci are comparable (>10-5 per locus per generation to that of the most diverse tandemly repeated regions found in other less diverse bacteria. Conclusion The frequency, location and duplicate nature of tandemly repeated regions within the B. pseudomallei genome indicate that these tandem repeat regions may play a role in generating and maintaining adaptive genomic variation. Multiple-locus VNTR analysis revealed extensive diversity within the global isolate set containing B. pseudomallei and B. mallei, and it detected genotypic differences within clonal lineages of both species that were

  20. Large tandem accelerators

    Jones, C.M.

    1976-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of tandem accelerators designed to operate at maximum terminal potentials in the range 14 to 30 MV. In addition, a number of older tandem accelerators are now being significantly upgraded to improve their heavy ion performance. Both of these developments have reemphasized the importance of negative heavy ion sources. The new large tandem accelerators are described, and the requirements placed on negative heavy ion source technology by these and other tandem accelerators used for the acceleration of heavy ions are discussed. First, a brief description is given of the large tandem accelerators which have been completed recently, are under construction, or are funded for construction, second, the motivation for construction of these accelerators is discussed, and last, criteria for negative ion sources for use with these accelerators are presented

  1. Tandem mirror reactor

    Moir, R.W.; Barr, W.L.; Carlson, G.A.

    1977-01-01

    A parametric analysis and a preliminary conceptual design for a 1000 MWe Tandem Mirror Reactor (TMR) are described. The concept is sufficiently attractive to encourage further work, both for a pure fusion TMR and a low technology TMR Fusion-Fission Hybrid

  2. The tandem betatron accelerator

    Keinigs, R.

    1991-01-01

    This paper reports that the tandem betatron is a compact, high-current induction accelerator that has the capability to accelerate electrons to an energy of order one gigavolt. Based upon the operating principle of a conventional betatron, the tandem betatron employs two synchronized induction cores operating 180 degrees out of phase. Embedded within the cores are the vacuum chambers, and these are connected by linear transport sections to allow for moving the beam back and forth between the two betatrons. The 180 degree phase shift between the core fluxes permits the circumvention of the flux swing constraint that limits the maximum energy gain of a conventional betatron. By transporting the beam between the synchronized cores, an electron can access more than one acceleration cycle, and thereby continue to gain energy. This added degree of freedom also permits a significant decrease in the size of the magnet system. Biasing coils provide independent control of the confining magnetic field. Provided that efficient beam switching can be performed, it appears feasible that a one gigavolt electron beam can be generated and confined. At this energy, a high current electron beam circulating in a one meter radius orbit could provide a very intense source of short wavelength (λ < 10 nm) synchrotron radiation. This has direct application to the emerging field of x-ray lithography. At more modest energies (10 MeV-30 MEV) a compact tandem betatron could be employed in the fields of medical radiation therapy, industrial radiography, and materials processing

  3. Tandem accelerator operation and improvements

    Yang Bingfan; Zhang Canzhe; Qin Jiuchang; Hu Yueming; Zhang Guilian; Jiang Yongliang; Hou Deyi; Yang Weimin; Yang Zhiren; Su Shengyong; Kan Chaoxin; Liu Dezhong; Wang Liyong; Bao Yiwen; You Qubo; Yang Tao; Zhang Yan; Zhou Lipeng; Chai Shiqin; Wang Meiyan

    1998-01-01

    The scheduled operation of HI-13 tandem accelerator for various experiments was performed well in 1996 and 1997. The machine running time was 4600 h and 4182 h while the beam time was 3845 h and 3712 h in 1996 and 1997, respectively. The operation of HI-13 tandem accelerator is pretty well. The beam distribution with terminal voltage and the distribution of beam time with ion species are shown out. The development of accelerating tubes for HI-13 tandem is in progress

  4. A multi locus variable number of tandem repeat analysis (MLVA scheme for Streptococcus agalactiae genotyping

    Mereghetti Laurent

    2011-07-01

    Full Text Available Abstract Background Multilocus sequence typing (MLST is currently the reference method for genotyping Streptococcus agalactiae strains, the leading cause of infectious disease in newborns and a major cause of disease in immunocompromised children and adults. We describe here a genotyping method based on multiple locus variable number of tandem repeat (VNTR analysis (MLVA applied to a population of S. agalactiae strains of various origins characterized by MLST and serotyping. Results We studied a collection of 186 strains isolated from humans and cattle and three reference strains (A909, NEM316 and 2603 V/R. Among 34 VNTRs, 6 polymorphic VNTRs loci were selected for use in genotyping of the bacterial population. The MLVA profile consists of a series of allele numbers, corresponding to the number of repeats at each VNTR locus. 98 MLVA genotypes were obtained compared to 51 sequences types generated by MLST. The MLVA scheme generated clusters which corresponded well to the main clonal complexes obtained by MLST. However it provided a higher discriminatory power. The diversity index obtained with MLVA was 0.960 compared to 0.881 with MLST for this population of strains. Conclusions The MLVA scheme proposed here is a rapid, cheap and easy genotyping method generating results suitable for exchange and comparison between different laboratories and for the epidemiologic surveillance of S. agalactiae and analyses of outbreaks.

  5. Tandem accelerators, 1973--1974

    Howard, F.T.

    1974-01-01

    High voltage tandem accelerators are very important instruments in the field of nuclear physics research, especially in the acceleration of heavy ions. This survey identifies 77 tandems installed in 21 countries; of these, 34 are in the United States. Most installations have supplied data sheets identifying their machines and briefly characterizing their research programs. (U.S.)

  6. MHD stability of tandem mirrors

    Poulsen, P.; Molvik, A.; Shearer, J.

    1982-01-01

    The TMX-Upgrade experiment was described, and the manner in which various plasma parameters could be affected was discussed. The initial analysis of the MHD stability of the tandem mirror was also discussed, with emphasis on the negative tandem configuration

  7. Tandems as injectors for synchrotrons

    Ruggiero, A.G.

    1993-01-01

    This is a review on the use of tandem electrostatic accelerators for injection and fitting of synchrotrons to accelerate intense beams of heavy ions to relativistic energies. The paper emphasizes the need of operating the tandems in pulsed mode for this application. It has been experimentally demonstrated that at present this type of accelerator still provides the most reliable and best performance. (orig.)

  8. JAERI tandem-accelerator and tandem-booster

    Yoshida, Tadashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In 1982, aiming at the new development of atomic energy research, the tandem accelerator of Japan Atomic Energy Research Institute (JAERI) was installed. In fiscal year 1993, the superconducting boosters which can increase the ion energy by up to 4 times were added, and the research in the region below 1000 MeV became possible. Those are electrostatic type accelerators which are easy to be used especially in basic research field, and are useful for future research. The tandem accelerator has been operated while maintaining the first class performance as the accelerator for various kinds of heavy ion beam. It has the special shape among electrostatic type accelerators, and is excellent in the easiness of control and stability. The main particulars of the tandem accelerator are shown. As for the ion sources of the tandem accelerator, three cesium sputter type ion sources are installed on two high voltage stands. The kinds of the ions which can be accelerated are mainly negative ions. As the improvement, electron cyclotron resonance (ECR) ion sources are expected to be adopted. As for the tandem boosters, the 1/4 wavelength type resonance hollow cylinder was adopted. The constitution of the tandem boosters is explained. The way of utilizing the tandem accelerator system and the aim for hereafter are reported. (K.I.)

  9. Evaluation and selection of tandem repeat loci for a Brucella MLVA typing assay

    Denoeud France

    2006-02-01

    Full Text Available Abstract Background The classification of Brucella into species and biovars relies on phenotypic characteristics and sometimes raises difficulties in the interpretation of the results due to an absence of standardization of the typing reagents. In addition, the resolution of this biotyping is moderate and requires the manipulation of the living agent. More efficient DNA-based methods are needed, and this work explores the suitability of multiple locus variable number tandem repeats analysis (MLVA for both typing and species identification. Results Eighty tandem repeat loci predicted to be polymorphic by genome sequence analysis of three available Brucella genome sequences were tested for polymorphism by genotyping 21 Brucella strains (18 reference strains representing the six 'classical' species and all biovars as well as 3 marine mammal strains currently recognized as members of two new species. The MLVA data efficiently cluster the strains as expected according to their species and biovar. For practical use, a subset of 15 loci preserving this clustering was selected and applied to the typing of 236 isolates. Using this MLVA-15 assay, the clusters generated correspond to the classical biotyping scheme of Brucella spp. The 15 markers have been divided into two groups, one comprising 8 user-friendly minisatellite markers with a good species identification capability (panel 1 and another complementary group of 7 microsatellite markers with higher discriminatory power (panel 2. Conclusion The MLVA-15 assay can be applied to large collections of Brucella strains with automated or manual procedures, and can be proposed as a complement, or even a substitute, of classical biotyping methods. This is facilitated by the fact that MLVA is based on non-infectious material (DNA whereas the biotyping procedure itself requires the manipulation of the living agent. The data produced can be queried on a dedicated MLVA web service site.

  10. Tandem Van de Graaff facility

    Federal Laboratory Consortium — Completed in 1970, the Tandem Van de Graaff facility was for many years the world's largest electrostatic accelerator facility. It can provide researchers with beams...

  11. Potential measurements in tandem mirrors

    Glowienka, J.C.

    1985-11-01

    The US mirror program has begun conducting experiments with a thermal barrier tandem mirror configuration. This configuration requires a specific axial potential profile and implies measurements of potential for documentation and optimization of the configuration. This report briefly outlines the motivation for the thermal barrier tandem mirror and then outlines the techniques used to document the potential profile in conventional and thermal barrier tandem mirrors. Examples of typical data sets from the world's major tandem mirror experiments, TMX and TMX-U at Lawrence Livermore National Laboratory (LLNL) and Gamma 10 at Tsukuba University in Japan, and the current interpretation of the data are discussed together with plans for the future improvement of measurements of plasma potential

  12. Superconducting linacs used with tandems

    Ben-Zvi, I.

    1984-01-01

    The main features of superconducting linacs used as post-accelerators of tandems are reviewed. Various aspects of resonators, cryogenics and electronics are discussed, and recent advances in the field are presented. (orig.)

  13. Tandem Terminal Ion Source

    Harper, G.C.; Lindner, C.E.; Myers, A.W.; Wechel, T.D. van

    2000-01-01

    OAK-B135 Tandem Terminal Ion Source. The terminal ion source (TIS) was used in several experiments during this reporting period, all for the 7 Be(γ) 8 B experiment. Most of the runs used 1 H + at terminal voltages from 0.3 MV to 1.5 MV. One of the runs used 2 H + at terminal voltage of 1.4 MV. The other run used 4 He + at a terminal voltage of 1.37 MV. The list of experiments run with the TIS to date is given in table 1 below. The tank was opened four times for unscheduled source repairs. On one occasion the tank was opened to replace the einzel lens power supply which had failed. The 10 kV unit was replaced with a 15 kV unit. The second time the tank was opened to repair the extractor supply which was damaged by a tank spark. On the next occasion the tank was opened to replace a source canal which had sputtered away. Finally, the tank was opened to replace the discharge bottle which had been coated with aluminum sputtered from the exit canal

  14. Tandem Terminal Ion Source

    None

    2000-01-01

    OAK-B135 Tandem Terminal Ion Source. The terminal ion source (TIS) was used in several experiments during this reporting period, all for the(sup 7)Be((gamma))(sup 8)B experiment. Most of the runs used(sup 1)H(sup+) at terminal voltages from 0.3 MV to 1.5 MV. One of the runs used(sup 2)H(sup+) at terminal voltage of 1.4 MV. The other run used(sup 4)He(sup+) at a terminal voltage of 1.37 MV. The list of experiments run with the TIS to date is given in table 1 below. The tank was opened four times for unscheduled source repairs. On one occasion the tank was opened to replace the einzel lens power supply which had failed. The 10 kV unit was replaced with a 15 kV unit. The second time the tank was opened to repair the extractor supply which was damaged by a tank spark. On the next occasion the tank was opened to replace a source canal which had sputtered away. Finally, the tank was opened to replace the discharge bottle which had been coated with aluminum sputtered from the exit canal

  15. JAERI 20 MV tandem accelerator

    Tsukada, Kineo; Harada, Kichinosuke

    1977-01-01

    Accelerators have been developed as the experimental apparatuses for the studies on nuclei and elementary particles. One direction of the development is the acceleration of protons and electrons to more and more high energy, and another direction is the acceleration of heavy ions up to uranium to several MeV up to several hundreds MeV. However recently, accelerators are used as the useful tools for the studies in wider fields. There are electrostatic acceleration and high frequency acceleration in ion acceleration, and at present, super-large accelerators are high frequency acceleration type. In Japan Atomic Energy Research Institute, it was decided in 1975 to construct an electrostatic accelerator of tandem type in order to accelerate heavy ions. In case of the electrostatic acceleration, the construction is relatively simple, the acceleration of heavy ions is easy, the property of the ion beam is very good, and the energy is stable. Especially, the tandem type is convenient for obtaining high energy. The tandem accelerator of 20 MV terminal voltage was ordered from the National Electrostatics Corp., USA, and is expected to be completed in 1978. The significance of heavy ion acceleration in the development and research of atomic energy, tandem van de Graaff accelerators, the JAERI 20MV tandem accelerator, and the research project with this accelerator are described. (Kako, I.)

  16. Introduction to tandem mirror physics

    Kesner, J.; Gerver, M.J.; Lane, B.G.; McVey, B.D.; Catto, P.J.; D'Ippolito, D.A.; Myra, J.R.

    1983-09-01

    This monograph, prepared jointly by the MIT Plasma Fusion Center Mirror Fusion group and SAI, Boulder, Colorado, presents a review of the development of mirror fusion theory from its conception some thirty years ago to the present. Pertinent historic experiments and their contribution are discussed to set the stage for a detailed analysis of current experiments and the problems which remain to be solved in bringing tandem mirror magnetic confinement fusion to fruition. In particular, Chapter III discusses in detail the equilibrium and stability questions which must be dealt with before tandem mirror reactors become feasible, while Chapters IV and V discuss some of the current machines and those under construction which will help to resolve critical issues in both physics and engineering whose solutions are necessary to the commercialization of tandem mirror fusion

  17. DNA fingerprinting of Mycobacterium leprae strains using variable number tandem repeat (VNTR) - fragment length analysis (FLA).

    Jensen, Ronald W; Rivest, Jason; Li, Wei; Vissa, Varalakshmi

    2011-07-15

    The study of the transmission of leprosy is particularly difficult since the causative agent, Mycobacterium leprae, cannot be cultured in the laboratory. The only sources of the bacteria are leprosy patients, and experimentally infected armadillos and nude mice. Thus, many of the methods used in modern epidemiology are not available for the study of leprosy. Despite an extensive global drug treatment program for leprosy implemented by the WHO, leprosy remains endemic in many countries with approximately 250,000 new cases each year. The entire M. leprae genome has been mapped and many loci have been identified that have repeated segments of 2 or more base pairs (called micro- and minisatellites). Clinical strains of M. leprae may vary in the number of tandem repeated segments (short tandem repeats, STR) at many of these loci. Variable number tandem repeat (VNTR) analysis has been used to distinguish different strains of the leprosy bacilli. Some of the loci appear to be more stable than others, showing less variation in repeat numbers, while others seem to change more rapidly, sometimes in the same patient. While the variability of certain VNTRs has brought up questions regarding their suitability for strain typing, the emerging data suggest that analyzing multiple loci, which are diverse in their stability, can be used as a valuable epidemiological tool. Multiple locus VNTR analysis (MLVA) has been used to study leprosy evolution and transmission in several countries including China, Malawi, the Philippines, and Brazil. MLVA involves multiple steps. First, bacterial DNA is extracted along with host tissue DNA from clinical biopsies or slit skin smears (SSS). The desired loci are then amplified from the extracted DNA via polymerase chain reaction (PCR). Fluorescently-labeled primers for 4-5 different loci are used per reaction, with 18 loci being amplified in a total of four reactions. The PCR products may be subjected to agarose gel electrophoresis to verify the

  18. JAERI tandem annual report, 1982

    Harada, Kichinosuke; Maruyama, Michio; Ozawa, Kunio; Shikazono, Naomoto; Tamura, Tsutomu; Tanaka, Shigeya

    1983-06-01

    This annual report describes research activities which have been performed with JAERI tandem accelerator from September 1, 1981 to March 31, 1983. Summary reports of 38 papers, publications, personnel and a list of co-operative researches with universities are contained. (author)

  19. JAERI Tandem annual report 1983

    Harada, Kichinosuke; Maruyama, Michio; Okashita, Hiroshi; Ozawa, Kunio; Shikazono, Naomoto; Tanaka, Shigeya

    1984-07-01

    This annual report describes research activities which have been performed with JAERI tandem accelerator from April 1, 1983 to March 31, 1984. Summary reports of 32 papers, publications, personnel and a list of co-operative reserches with universities are contained. (author)

  20. Status of tandem mirror theory

    Baldwin, D.E.

    1979-01-01

    This report contains the text and slides used for the review talk on tandem mirror theory presented at the meeting of the Division of Plasma Physics, A.P.S., Boston, MA, November 12-16, 1979. Topics covered include classical confinement, equilibria, MHD- and micro-stability, radial transport, and thermal barriers

  1. A study of reflex tandem accelerator

    Nakajima, Takao; Morinobu, Shunpei; Gono, Yasuyuki; Sagara, Kenji; Sugimitsu, Tsuyoshi; Mitarai, Shiro; Nakamura, Hiroyuki; Ikeda, Nobuo; Morikawa, Tsuneyasu [Kyushu Univ., Fukuoka (Japan). Faculty of Science

    1996-12-01

    An investigation on `developing research theme and its realizing experimental apparatus` based on the tandem accelerator facility is executed. At a standpoint of recognition on essentiality of preparation, improvement or novel technical development capable of extreme increase in capacity of the tandem accelerator facility to form COE with high uniqueness, proposal of numerous ideas and their investigations and searches were conducted. In this paper, consideration results of `beam reacceleration using tandem accelerator` were shown as follows: (1) Short life unstable nuclei formed by nuclear reaction using tandem acceleration primary beam is ionized to negative and to reaccelerate by using the same tandem accelerator. And (2) by combination of plural electrons with the tandem primary accelerated beam, numbers of charge is reduced to reaccelerate by the tandem. (G.K.)

  2. Tandem electrostatic accelerators for BNCT

    Ma, J.C.

    1994-01-01

    The development of boron neutron capture therapy (BNCT) into a viable therapeutic modality will depend, in part, on the availability of suitable neutron sources compatible with installation in a hospital environment. Low-energy accelerator-based intense neutron sources, using electrostatic or radio frequency quadrupole proton accelerators have been suggested for this purpose and are underdevelopment at several laboratories. New advances in tandem electrostatic accelerator technology now allow acceleration of the multi-milliampere proton beams required to produce therapeutic neutron fluxes for BNCT. The relatively compact size, low weight and high power efficiency of these machines make them particularly attractive for installation in a clinical or research facility. The authors will describe the limitations on ion beam current and available neutron flux from tandem accelerators relative to the requirements for BNCT research and therapy. Preliminary designs and shielding requirements for a tandern accelerator-based BNCT research facility will also be presented

  3. MINIMARS tandem mirror reactor study

    Perkins, L.J.; Logan, B.G.; Doggett, J.N.

    1986-01-01

    During 1985-1986, Lawrence Livermore National Lab., in partnership with the Fusion Engineering Design Center of Oak Ridge National Lab., the Univ. of Wisconsin, TRW, Grumman Aerospace Corporation, General Dynamics/Convair, Argonne National Lab., and the Canadian Fusion Fuels Technology Project, has conducted the conceptual design of MINIMARS, a small commercial tandem mirror reactor with novel octopole end plugs. With a net electric output of 600 MW(e), MINIMARS is expressly designed for short (∼4- to 5-yr) construction time, factory-built modules, and a passively safe blanket and thermal cycle. In this way, we intend to achieve a small reactor based on the tandem mirror principle that will minimize utility financial risk, thereby providing an attractive alternative to the more conventional large fusion plant designs encountered to date

  4. "Nanocrystal bilayer for tandem catalysis"

    Yamada, Yusuke; Tsung, Chia Kuang; Huang, Wenyu; Huo, Ziyang; E.Habas, Susan E; Soejima, Tetsuro; Aliaga, Cesar E; Samorjai, Gabor A; Yang, Peidong

    2011-01-24

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts

  5. Tandem mirror technology demonstration facility

    1983-10-01

    This report describes a facility for generating engineering data on the nuclear technologies needed to build an engineering test reactor (ETR). The facility, based on a tandem mirror operating in the Kelley mode, could be used to produce a high neutron flux (1.4 MW/M/sup 2/) on an 8-m/sup 2/ test area for testing fusion blankets. Runs of more than 100 h, with an average availability of 30%, would produce a fluence of 5 mW/yr/m/sup 2/ and give the necessary experience for successful operation of an ETR.

  6. Tandem mirror technology demonstration facility

    1983-10-01

    This report describes a facility for generating engineering data on the nuclear technologies needed to build an engineering test reactor (ETR). The facility, based on a tandem mirror operating in the Kelley mode, could be used to produce a high neutron flux (1.4 MW/M 2 ) on an 8-m 2 test area for testing fusion blankets. Runs of more than 100 h, with an average availability of 30%, would produce a fluence of 5 mW/yr/m 2 and give the necessary experience for successful operation of an ETR

  7. Genetic variation observed at three tetrameric short tandem repeat loci HumTHO1, TPOX, and CSF1PO--in five ethnic population groups of northeastern India.

    Ranjan, D; Kashyap, V K

    2001-01-01

    This paper portrays the genetic variation observed at three tetrameric short tandem repeat (STR) loci HumTHO1, TPOX, and CSF1PO in five ethnic population groups from northeastern India. The study also specifies the suitability of use of these markers for forensic testing. The populations studied included three tribal groups (Kuki, Naga and Hmar), one Mongoloid caste group (Meitei), and a religious caste group (Manipuri Muslims). The loci were highly polymorphic in the populations, and all loci met Hardy-Weinberg expectations. No evidence for association of alleles among the loci was detected. The probability of match for the three loci of the most frequent genotype in the five population groups ranged between 2.6 x 10(-4) and 6.6 x 10(-5). The average heterozygosity among the population groups was approximately 70% with the overall extent of gene differentiation among the five groups being high (Gst = 0.046). Genetic affinity among the populations reveal very close association between the Kuki, Hmar, Naga, and Meitei. The Manipuri Muslims, despite being found in the same region, have had no admixture with these populations and maintain a substantial distance with the other groups. The genetic polymorphism data suggest that the studied systems can be used for human identity testing to estimate the frequency of a multiple locus STR DNA profile in population groups of northeastern India.

  8. Injector of the Utrecht EN tandem

    Borg, K. van der; Haas, A.P. de; Hoogenboom, A.M.; Strasters, B.A.; Vermeer, A.; Zwol, N.A. van (Rijksuniversiteit Utrecht (Netherlands). Fysisch Lab.)

    1984-02-15

    An injector has been built to obtain improved beam transmission through the EN tandem. The injector has been provided with a 90/sup 0/ analysing magnet, m/..delta..m=300, and 130 kV preacceleration. Beam optics calculations have been made for the injector and tandem. The injector has been equipped with a fiber optics control and data acquisition system.

  9. The injector of the Utrecht EN tandem

    Borg, K. van der; Haas, A.P. de; Hoogenboom, A.M.; Strasters, B.A.; Vermeer, A.; Zwol, N.A. van

    1984-01-01

    An injector has been built to obtain improved beam transmission through the EN tandem. The injector has been provided with a 90 0 analysing magnet, m/Δm=300, and 130 kV preacceleration. Beam optics calculations have been made for the injector and tandem. The injector has been equipped with a fiber optics control and data acquisition system. (orig.)

  10. The Kyoto University tandem upgrading project

    Nakamura, Masanobu; Shimoura, Susumu; Takimoto, Kiyohiko; Sakaguchi, Harutaka; Kobayashi, Shinsaku

    1988-01-01

    A brief description on the Kyoto University tandem upgrading project. The project consists of replacing the old 5 MV tandem Van de Graaff by an 8UDH pelletron. The old pressure vessel and beam lines are used again without significant modification. The project is planned to be completed at the end of 1989. (orig.)

  11. Parametric studies of tandem mirror reactors

    Carlson, G.A.; Boghosian, B.M.; Fink, J.H.; Myall, J.O.; Neef, W.S. Jr.

    1979-01-01

    This report, along with its companion, An Improved Tandem Mirror Reactor, discusses the recent progress and present status of our tandem mirror reactor studies. This report presents the detailed results of parametric studies up to, but not including, the very new ideas involving thermal barriers

  12. Packet models revisited: tandem and priority systems

    M.R.H. Mandjes (Michel)

    2004-01-01

    textabstractWe examine two extensions of traditional single-node packet-scale queueing models: tandem networks and (strict) priority systems. Two generic input processes are considered: periodic and Poisson arrivals. For the two-node tandem, an exact expression is derived for the joint distribution

  13. Tandem Translation Classroom: A Case Study

    Kim, Dohun; Koh, Taejin

    2018-01-01

    The transition to student-centred learning, advances in teleconferencing tools, and active international student exchange programmes have stimulated tandem learning in many parts of the world. This pedagogical model is based on a mutual language exchange between tandem partners, where each student is a native speaker in the language the…

  14. Device operation of organic tandem solar cells

    Hadipour, A.; de Boer, B.; Blom, P. W. M.

    2008-01-01

    A generalized methodology is developed to obtain the current-voltage characteristic of polymer tandem solar cells by knowing the electrical performance of both sub cells. We demonstrate that the electrical characteristics of polymer tandem solar cells are correctly predicted for both the series and

  15. Status of JAERI tandem accelerator

    Yoshida, Tadashi; Kanda, Susumu; Takeuchi, Suehiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] (and others)

    2001-02-01

    JAERI Tandem Accelerator had been operated approximately 230 days in fiscal year of 1999. Meanwhile, we had three times of maintenance period with vent. Total operation-times were 5273 hours. We could not carry out the experiment using rare gas, due to malfunction of the RF power supply for the ECR ion source. The type of the RF power supply is peculiar and it is impossible to get spare parts for repair. We are now investigating the backup RF power supply. The power supply for the magnet became unstable due to degradation of insulation in the shunt resistance, which is used for feedback stabilization. Stability was recovered after cleaning. The acrylic resin shaft was cracked. This cracks have a potential for severe accidents. So far bearing of the shaft has no problem. The reason of cracks may be self-destruction by charge accumulation in the shaft. JAERI Tandem Accelerator is approximately 20 years old. There appear requirements on the higher ion currents for additional ion species. Therefore, authors are investigating cost effective improvement plans of RFQ (Radio Frequency Quadra-pole) and IH type accelerator based on KEK (High Energy Accelerator Research Organization) R and D. As a whole, maintenance services for the control system are increasing due to some changes of computer programs. There are some difficulties to keep skilled personnel for facilities operation. Authors are gradually increasing hired personnel with contract from 1993. However, loads for JAERI permanent staffs are still heavy. It takes much longer time to educate skilled persons especially for safety. (Y. Tanaka)

  16. A novel typing method for Listeria monocytogenes using high-resolution melting analysis (HRMA) of tandem repeat regions.

    Ohshima, Chihiro; Takahashi, Hajime; Iwakawa, Ai; Kuda, Takashi; Kimura, Bon

    2017-07-17

    Listeria monocytogenes, which is responsible for causing food poisoning known as listeriosis, infects humans and animals. Widely distributed in the environment, this bacterium is known to contaminate food products after being transmitted to factories via raw materials. To minimize the contamination of products by food pathogens, it is critical to identify and eliminate factory entry routes and pathways for the causative bacteria. High resolution melting analysis (HRMA) is a method that takes advantage of differences in DNA sequences and PCR product lengths that are reflected by the disassociation temperature. Through our research, we have developed a multiple locus variable-number tandem repeat analysis (MLVA) using HRMA as a simple and rapid method to differentiate L. monocytogenes isolates. While evaluating our developed method, the ability of MLVA-HRMA, MLVA using capillary electrophoresis, and multilocus sequence typing (MLST) was compared for their ability to discriminate between strains. The MLVA-HRMA method displayed greater discriminatory ability than MLST and MLVA using capillary electrophoresis, suggesting that the variation in the number of repeat units, along with mutations within the DNA sequence, was accurately reflected by the melting curve of HRMA. Rather than relying on DNA sequence analysis or high-resolution electrophoresis, the MLVA-HRMA method employs the same process as PCR until the analysis step, suggesting a combination of speed and simplicity. The result of MLVA-HRMA method is able to be shared between different laboratories. There are high expectations that this method will be adopted for regular inspections at food processing facilities in the near future. Copyright © 2017. Published by Elsevier B.V.

  17. Multi-locus variable-number tandem repeat analysis of Chinese Brucella strains isolated from 1953 to 2013.

    Tian, Guo-Zhong; Cui, Bu-Yun; Piao, Dong-Ri; Zhao, Hong-Yan; Li, Lan-Yu; Liu, Xi; Xiao, Pei; Zhao, Zhong-Zhi; Xu, Li-Qing; Jiang, Hai; Li, Zhen-Jun

    2017-05-02

    Brucellosis was a common human and livestock disease caused by Brucella strains, the category B priority pathogens by the US Center for Disease Control (CDC). Identified as a priority disease in human and livestock populations, the increasing incidence in recent years in China needs urgent control measures for this disease but the molecular background important for monitoring the epidemiology of Brucella strains at the national level is still lacking. A total of 600 Brucella isolates collected during 60 years (from 1953 to 2013) in China were genotyped by multiple locus variable-number tandem repeat analysis (MLVA) and the variation degree of MLVA11 loci was calculated by the Hunter Gaston Diversity Index (HGDI) values. The charts and map were processed by Excel 2013, and cluster analysis and epidemiological distribution was performed using BioNumerics (version 5.1). The 600 representative Brucella isolates fell into 104 genotypes with 58 singleton genotypes by the MLVA11 assay, including B. melitensis biovars 2 and 3 (five main genotypes), B. abortus biovars 1 and 3 (two main genotypes), B. suis biovars 1 and 3 (three main genotypes), and B. canis (two main genotypes) respectively. While most B. suis biovar 1 and biovar 3 were respectively found in northern provinces and southern provinces, B. melitensis and B. abortus strains were dominant in China. Canine Brucellosis was only found in animals without any human cases reported. Eight Brucellosis epidemic peaks emerged during the 60 years between 1953 and 2013: 1955 - 1959, 1962 - 1969, 1971 - 1975, 1977 - 1983, 1985 - 1989, 1992 - 1997, 2000 - 2008 and 2010 - 2013 in China. Brucellosis has its unique molecular epidemiological patterns with specific spatial and temporal distribution according to MLVA. IDOP-D-16-00101.

  18. Tandem catalysis: a new approach to polymers.

    Robert, Carine; Thomas, Christophe M

    2013-12-21

    The creation of polymers by tandem catalysis represents an exciting frontier in materials science. Tandem catalysis is one of the strategies used by Nature for building macromolecules. Living organisms generally synthesize macromolecules by in vivo enzyme-catalyzed chain growth polymerization reactions using activated monomers that have been formed within cells during complex metabolic processes. However, these biological processes rely on highly complex biocatalysts, thus limiting their industrial applications. In order to obtain polymers by tandem catalysis, homogeneous and enzyme catalysts have played a leading role in the last two decades. In the following feature article, we will describe selected published efforts to achieve these research goals.

  19. Tandem Mirror Reactor Systems Code (Version I)

    Reid, R.L.; Finn, P.A.; Gohar, M.Y.

    1985-09-01

    A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost

  20. TASKA - Tandem Spiegelmaschine Karlsruhe. Vol. 1

    1982-06-01

    TASKA (Tandem Spiegelmaschine Karlsruhe) is a near term engineering test facility based on a tandem mirror concept with thermal barriers. The main objectives of this study were to develop a preconceptual design of a facility that could provide engineering design information for a Demonstration Fusion Power Reactor. Thus TASKA has to serve as testbed for technologies of plasma engineering, superconducting magnets, materials, plasma heating, breeding and test blankets, tritium technology, and remote handling. (orig.) [de

  1. Feasibility study on tandem fuel cycle

    Han, P.S.; Suh, I.S.; Rim, C.S.; Kim, B.K.; Suh, K.S.; Ro, S.K.; Juhn, P.I.; Kim, S.Y.

    1983-01-01

    The objective of this feasibility study is to review and assess the current state of technology concerning the tandem fuel cycle. Based on the results from this study, a long-term development plan suitable for Korea has been proposed for this cycle, i.e., the PWR → CANDU tandem fuel cycle which used plutonium and uranium, recovered from spent PWR fuel by co-processing, as fuel material for CANDU reactors. (Author)

  2. TASKA - Tandem Spiegelmaschine Karlsruhe. Vol. 2

    1982-06-01

    TASKA (Tandem Spiegelmaschine Karlsruhe) is a near term engineering test facility based on a tandem mirror concept with thermal barriers. The main objectives of this study were to develop a preconceptual design of a facility that could provide engineering design information for a Demonstration Fusion Power Reactor. Thus TASKA has to serve as testbed for technologies of plasma engineering, superconducting magnets, materials, plasma heating, breeding and test blankets, tritium technology, and remote handling. (orig.) [de

  3. North-American MP Tandem accelerators

    Wegner, H.E.; Thieberger, P.

    1977-01-01

    There are six North-American MP Tandem accelerators: Yale; Minnesota; Chalk River; Rochester; and two at Brookhaven. The current status and operating characteristics of these six tandem accelerators are discussed. Upgrade and special improvements of the different machines is reviewed and new developments since the last Electrostatic Conference are discussed in detail. The overall operating characteristics of the different machines during the last year of operation are compared

  4. Vortex shedding from tandem cylinders

    Alam, Md. Mahbub; Elhimer, Mehdi; Wang, Longjun; Jacono, David Lo; Wong, C. W.

    2018-03-01

    An experimental investigation is conducted on the flow around tandem cylinders for ranges of diameter ratio d/ D = 0.25-1.0, spacing ratio L/ d = 5.5-20, and Reynolds number Re = 0.8 × 104-2.42 × 104, where d and D are the diameters of the upstream and downstream cylinders, respectively, L is the distance from the upstream cylinder center to the forward stagnation point of the downstream one. The focus is given on examining the effects of d/ D, L/ d and Re on Strouhal number St, flow structures and fluid forces measured using hotwire, particle image velocimetry (PIV) and load cell measurement techniques, respectively. Changes in d/ D and L/ d in the ranges examined lead to five flow regimes, namely lock-in, intermittent lock-in, no lock-in, subharmonic lock-in and shear-layer reattachment regimes. Time-mean drag coefficient ( C D) and fluctuating drag and lift coefficients ({C^'D} and {C^'L}) are more sensitive to L/ d than d/ D. The scenario is opposite for St where d/ D is more prominent than L/ d to change the St. The detailed facet of the dependence on d/ D and L/ d of C D, {C^'D}, {C^'L} and St is discussed based on shear-layer velocity, approaching velocity, vortex formation length, and wake width.

  5. Tandem mass spectrometry at low kinetic energy

    Cooks, R.G.; Hand, O.W.

    1987-01-01

    Recent progress in mass spectrometry, as applied to molecular analysis, is reviewed with emphasis on tandem mass spectrometry. Tandem instruments use multiple analyzers (sector magnets, quadrupole mass filters and time-of-flight devices) to select particular molecules in ionic form, react them in the gas-phase and then record the mass, momenta or kinetic energies of their products. The capabilities of tandem mass spectrometry for identification of individual molecules or particular classes of compounds in complex mixtures are illustrated. Several different types of experiments can be run using a tandem mass spectrometer; all share the feature of sifting the molecular mixture being analyzed on the basis of chemical properties expressed in terms of ionic mass, kinetic energy or charge state. Applications of mass spectrometry to biological problems often depend upon desorption methods of ionization in which samples are bombarded with particle beams. Evaporation of preformed charged species from the condensed phase into the vacuum is a particularly effective method of ionization. It is suggested that the use of accelerator mass spectrometers be extended to include problems of molecular analysis. In such experiments, low energy tandem mass spectrometry conducted in the eV or keV range of energies, would be followed by further characterization of the production ion beam using high selective MeV collision processes

  6. Tandemly Arrayed Genes in Vertebrate Genomes

    Deng Pan

    2008-01-01

    Full Text Available Tandemly arrayed genes (TAGs are duplicated genes that are linked as neighbors on a chromosome, many of which have important physiological and biochemical functions. Here we performed a survey of these genes in 11 available vertebrate genomes. TAGs account for an average of about 14% of all genes in these vertebrate genomes, and about 25% of all duplications. The majority of TAGs (72–94% have parallel transcription orientation (i.e., they are encoded on the same strand in contrast to the genome, which has about 50% of its genes in parallel transcription orientation. The majority of tandem arrays have only two members. In all species, the proportion of genes that belong to TAGs tends to be higher in large gene families than in small ones; together with our recent finding that tandem duplication played a more important role than retroposition in large families, this fact suggests that among all types of duplication mechanisms, tandem duplication is the predominant mechanism of duplication, especially in large families. Finally, several species have a higher proportion of large tandem arrays that are species-specific than random expectation.

  7. Mass spectrometry by means of tandem accelerators

    Tuniz, C.

    1985-01-01

    Mass spectrometry based on an accelerator allows to measure rare cosmogenic isotopes found in natural samples with isotopic abundances up to 10E-15. The XTU Tandem of Legnaro National Laboratories can measure mean heavy isotopes (36Cl, 41Ca, 129I) in applications interesting cosmochronology and Medicine. The TTT-3 Tandem of the Naples University has been modified in view of precision studies of C14 in Archeology, Paleantology and Geology. In this paper a review is made of principles and methodologies and of some applicationy in the framework of the National Program for mass spectrametry research with the aid of accelerators

  8. Thirty years of physics at the Bucharest tandem accelerator

    Dobrescu, S.; Marinescu, L.; Dumitru, G.; Cata-Danil, Gh.

    2003-01-01

    The main parameters of the Bucharest tandem accelerator, as well as the main milestones of its history since March 1973 when it was commissioned are shortly presented. A general presentation of the main basic and applied physics research so far undertaken at the tandem is given, ending with some ideas related with the future perspectives of the tandem. (authors)

  9. STATIONARY DISTRIBUTION OF A TANDEM QUEUE WITH ADDITIONAL FLOWS ON THE STATIONS OF THE TANDEM

    V. I. Klimenok

    2017-01-01

    Full Text Available A tandem queueing system consisting of a finite number of multi-server stations without buffers is analized. The input flow at the first station is a ???????????? (Markovian arrival process. The customers from this flow aim to be served at all stations of the tandem. For any station, besides transit customers proceeding from the previous station, an additional ???????????? flow of new customers arrives at this station directly. Customers from this flow aim to be served at this station and all subsequent stations of the tandem. The service times of customer at the stations are exponentially distributed with the service rate depending of number of the station. The algorithms for culculation of stationary distributions and the loss probabilities associated with the tandem are given.

  10. A tandem queue with delayed server release

    Nawijn, W.M.

    1997-01-01

    We consider a tandem queue with two stations. The rst station is an s-server queue with Poisson arrivals and exponential service times. After terminating his service in the rst station, a customer enters the second station to require service at an exponential single server, while in the meantime he

  11. The PSI/ETH tandem accelerator facility

    Synal, H.A.; Doebeli, M.; Fuhrmann, H.; Kubik, P.W.; Nebiker, P.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)] [and others

    1997-09-01

    The 1996 operation of the PSI/ETH tandem accelerator at ETH Hoenggerberg is summarised with a detailed compilation of the beam time statistics and the statistics of AMS samples for the different radioisotopes and for the major fields of research. (author) 2 tab.

  12. Optimal dispatching in a tandem queue

    van Leeuwen, D.; Núñez Queija, R.

    2017-01-01

    We investigate a Markovian tandem queueing model in which service to the first queue is provided in batches. The main goal is to choose the batch sizes so as to minimize a linear cost function of the mean queue lengths. This model can be formulated as a Markov Decision Process (MDP) for which the

  13. Edge diagnostics for tandem mirror machines

    Allen, S.L.

    1984-01-01

    The edge plasma in a tandem mirror machine shields the plasma core from cold neutral gas and impurities. A variety of diagnostics are used to measure the fueling, shielding, and confinement of the edge plasma in both the end plug and central cell regions. Fast ion gauges and residual gas analyzers measure the gas pressure and composition outside of the plasma. An array of Langmuir probes is used to measure the electron density and temperature. Extreme ultraviolet (euv) and visible spectroscopy are used to measure both the impurity and deuterium densities and to estimate the shielding factor for the core plasma. The linear geometry of a tandem mirror also allows direct measurements of the edge plasma by sampling the ions and electrons lost but the ends of the machine. Representative data obtained by these diagnostics during operation of the Tandem Mirror Experiment (TMX) and Tandem Mirror Experiment-Upgrade (TMX-U) experiments are presented. Diagnostics that are currently being developed to diagnose the edge plasma are also discussed

  14. Tandem queue with server slow-down

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2007-01-01

    We study how rare events happen in the standard two-node tandem Jackson queue and in a generalization, the socalled slow-down network, see [2]. In the latter model the service rate of the first server depends on the number of jobs in the second queue: the first server slows down if the amount of

  15. 25 MV tandem accelerator at Oak Ridge

    Jones, C.M.

    1980-01-01

    A new heavy-ion accelerator facility is under construction at the Oak Ridge National Laboratory. A brief description of the scope and status of this project is presented with emphasis on the first operational experience with the 25 MV tandem accelerator

  16. Modelling of tandem cell temperature coefficients

    Friedman, D.J. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    This paper discusses the temperature dependence of the basic solar-cell operating parameters for a GaInP/GaAs series-connected two-terminal tandem cell. The effects of series resistance and of different incident solar spectra are also discussed.

  17. Tandem mirror next step conceptual design

    Doggett, J.N.; Damm, C.C.; Bulmer, R.H.

    1980-01-01

    A study was made to define the features of the experimental mirror fusion device - The Tandem Mirror Next Step, or TMNS - that will bridge the gap between present mirror confinement experiments and a power-producing reactor. We outline the project goals, describe some initial device parameters, and relate the technological requirements to ongoing development programs

  18. Quality evaluation of tandem mass spectral libraries.

    Oberacher, Herbert; Weinmann, Wolfgang; Dresen, Sebastian

    2011-06-01

    Tandem mass spectral libraries are gaining more and more importance for the identification of unknowns in different fields of research, including metabolomics, forensics, toxicology, and environmental analysis. Particularly, the recent invention of reliable, robust, and transferable libraries has increased the general acceptance of these tools. Herein, we report on results obtained from thorough evaluation of the match reliabilities of two tandem mass spectral libraries: the MSforID library established by the Oberacher group in Innsbruck and the Weinmann library established by the Weinmann group in Freiburg. Three different experiments were performed: (1) Spectra of the libraries were searched against their corresponding library after excluding either this single compound-specific spectrum or all compound-specific spectra prior to searching; (2) the libraries were searched against each other using either library as reference set or sample set; (3) spectra acquired on different mass spectrometric instruments were matched to both libraries. Almost 13,000 tandem mass spectra were included in this study. The MSforID search algorithm was used for spectral matching. Statistical evaluation of the library search results revealed that principally both libraries enable the sensitive and specific identification of compounds. Due to higher mass accuracy of the QqTOF compared with the QTrap instrument, matches to the MSforID library were more reliable when comparing spectra with both libraries. Furthermore, only the MSforID library was shown to be efficiently transferable to different kinds of tandem mass spectrometers, including "tandem-in-time" instruments; this is due to the coverage of a large range of different collision energy settings-including the very low range-which is an outstanding characteristics of the MSforID library.

  19. In situ detection of tandem DNA repeat length

    Yaar, R.; Szafranski, P.; Cantor, C.R.; Smith, C.L. [Boston Univ., MA (United States)

    1996-11-01

    A simple method for scoring short tandem DNA repeats is presented. An oligonucleotide target, containing tandem repeats embedded in a unique sequence, was hybridized to a set of complementary probes, containing tandem repeats of known lengths. Single-stranded loop structures formed on duplexes containing a mismatched (different) number of tandem repeats. No loop structure formed on duplexes containing a matched (identical) number of tandem repeats. The matched and mismatched loop structures were enzymatically distinguished and differentially labeled by treatment with S1 nuclease and the Klenow fragment of DNA polymerase. 7 refs., 4 figs.

  20. Current results of the tandem mirror experiment

    Drake, R.P.

    1980-01-01

    The basic operating characteristics of the Tandem Mirror Experiment, (TMX) at the Lawrence Livermore Laboratory in the USA have been established. Tandem-mirror plasmas have been produced using neutral-beam-fueled end plugs and a gas-fueled center cell. An axial potential well between the end plugs has been measured. There is direct evidence that this potential well enhances the axial confinement of the center-cell ions. The observed densities and loss currents are consistent with preliminary studies of the particle sources and losses near the magnetic axis. The observed confinement is consistent with theory when plasma fluctuations are low. When the requirement of drift-cyclotron loss-cone mode stability is violated, the plasma fluctuations degrade the center-cell confinement

  1. Operation of the tandem-linac accelerator

    Anon.

    1985-01-01

    The tandem-linac accelerator system is operated as a source of energetic heavy-ion projectiles for research in several areas of nuclear physics and occasionally in other areas of science. The accelerator system consists of a 9-MV tandem electrostatic accelerator and a superconducting-linac energy booster that can provide an additional 20 MV of acceleration. A figure shows the layout of this system, which will be operated in its present form until September 1985, when it will be incorporated into the larger ATLAS system. In both the present and future forms the accelerator is designed to provide the exceptional beam quality and overall versatility required for precision nuclear-structure research

  2. Moment approach to tandem mirror radial transport

    Siebert, K.D.; Callen, J.D.

    1986-02-01

    A moment approach is proposed for the study of tandem mirror radial transport in the resonant plateau regime. The salient features of the method are described with reference to axisymmetric tokamak transport theory. In particular, the importance of momentum conservation to the establishment of the azimuthal variations in the electrostatic potential is demonstrated. Also, an ad hoc drift kinetic equation is solved to determine parallel viscosity coefficients which are required to close the moment system

  3. Designs of tandem-mirror fusion reactors

    Carlson, G.A.; Barr, W.L.; Boghosian, B.M.

    1981-01-01

    We have completed a comparative evaluation of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axi-cell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axi-cell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability

  4. Tandem mirror next step: remote maintenance

    Doggett, J.N.; Damm, C.C.; Hanson, C.L.

    1980-01-01

    This study of the next proposed experiment in the Mirror Fusion Program, the Tandem Mirror Next Step (TMNS), has included serious consideration of the maintenance requirements of such a large source of high energy neutrons with its attendant throughput of tritium. Although maintenance will be costly in time and money, our conclusion is that with careful attention to a design for maintenance plan such a device can be reliably operated

  5. Cold Climate Heat Pumps Using Tandem Compressors

    Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

    2016-01-01

    In cold climate zones, e.g. ASHRAE climate regions IV and V, conventional electric air-source heat pumps (ASHP) do not work well, due to high compressor discharge temperatures, large pressure ratios and inadequate heating capacities at low ambient temperatures. Consequently, significant use of auxiliary strip heating is required to meet the building heating load. We introduce innovative ASHP technologies as part of continuing efforts to eliminate auxiliary strip heat use and maximize heating COP with acceptable cost-effectiveness and reliability. These innovative ASHP were developed using tandem compressors, which are capable of augmenting heating capacity at low temperatures and maintain superior part-load operation efficiency at moderate temperatures. Two options of tandem compressors were studied; the first employs two identical, single-speed compressors, and the second employs two identical, vapor-injection compressors. The investigations were based on system modeling and laboratory evaluation. Both designs have successfully met the performance criteria. Laboratory evaluation showed that the tandem, single-speed compressor ASHP system is able to achieve heating COP = 4.2 at 47 F (8.3 C), COP = 2.9 at 17 F (-8.3 C), and 76% rated capacity and COP = 1.9 at -13 F (-25 C). This yields a HSPF = 11.0 (per AHRI 210/240). The tandem, vapor-injection ASHP is able to reach heating COP = 4.4 at 47 F, COP = 3.1 at 17 F, and 88% rated capacity and COP = 2.0 at -13 F. This yields a HSPF = 12.0. The system modeling and further laboratory evaluation are presented in the paper.

  6. TandEM: Titan and Enceladus mission

    Coustenis, A.; Atreya, S.K.; Balint, T.; Brown, R.H.; Dougherty, M.K.; Ferri, F.; Fulchignoni, M.; Gautier, D.; Gowen, R.A.; Griffith, C.A.; Gurvits, L.I.; Jaumann, R.; Langevin, Y.; Leese, M.R.; Lunine, J.I.; McKay, C.P.; Moussas, X.; Muller-Wodarg, I.; Neubauer, F.; Owen, T.C.; Raulin, F.; Sittler, E.C.; Sohl, F.; Sotin, Christophe; Tobie, G.; Tokano, T.; Turtle, E.P.; Wahlund, J.-E.; Waite, J.H.; Baines, K.H.; Blamont, J.; Coates, A.J.; Dandouras, I.; Krimigis, T.; Lellouch, E.; Lorenz, R.D.; Morse, A.; Porco, C.C.; Hirtzig, M.; Saur, J.; Spilker, T.; Zarnecki, J.C.; Choi, E.; Achilleos, N.; Amils, R.; Annan, P.; Atkinson, D.H.; Benilan, Y.; Bertucci, C.; Bezard, B.; Bjoraker, G.L.; Blanc, M.; Boireau, L.; Bouman, J.; Cabane, M.; Capria, M.T.; Chassefiere, E.; Coll, P.; Combes, M.; Cooper, J.F.; Coradini, A.; Crary, F.; Cravens, T.; Daglis, I.A.; de Angelis, E.; De Bergh, C.; de Pater, I.; Dunford, C.; Durry, G.; Dutuit, O.; Fairbrother, D.; Flasar, F.M.; Fortes, A.D.; Frampton, R.; Fujimoto, M.; Galand, M.; Grasset, O.; Grott, M.; Haltigin, T.; Herique, A.; Hersant, F.; Hussmann, H.; Ip, W.; Johnson, R.; Kallio, E.; Kempf, S.; Knapmeyer, M.; Kofman, W.; Koop, R.; Kostiuk, T.; Krupp, N.; Kuppers, M.; Lammer, H.; Lara, L.-M.; Lavvas, P.; Le, Mouelic S.; Lebonnois, S.; Ledvina, S.; Li, Ji; Livengood, T.A.; Lopes, R.M.; Lopez-Moreno, J. -J.; Luz, D.; Mahaffy, P.R.; Mall, U.; Martinez-Frias, J.; Marty, B.; McCord, T.; Salvan, C.M.; Milillo, A.; Mitchell, D.G.; Modolo, R.; Mousis, O.; Nakamura, M.; Neish, Catherine D.; Nixon, C.A.; Mvondo, D.N.; Orton, G.; Paetzold, M.; Pitman, J.; Pogrebenko, S.; Pollard, W.; Prieto-Ballesteros, O.; Rannou, P.; Reh, K.; Richter, L.; Robb, F.T.; Rodrigo, R.; Rodriguez, S.; Romani, P.; Bermejo, M.R.; Sarris, E.T.; Schenk, P.; Schmitt, B.; Schmitz, N.; Schulze-Makuch, D.; Schwingenschuh, K.; Selig, A.; Sicardy, B.; Soderblom, L.; Spilker, L.J.; Stam, D.; Steele, A.; Stephan, K.; Strobel, D.F.; Szego, K.; Szopa,

    2009-01-01

    TandEM was proposed as an L-class (large) mission in response to ESA’s Cosmic Vision 2015–2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini–Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini–Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (Montgolfière) and possibly several landing probes to be delivered through the atmosphere.

  7. Feedback stabilized tandem Fabry-Perot interferometer

    Fukushima, Hiroyuki; Ito, Mikio; Shirasu, Hiroshi.

    1986-01-01

    A new system for measuring the isotopic ratio of uranium, in which two plane-type Fabry-Perot interferometers (tandem FP) are connected in series. The parallelism between the two FPs is achieved automatically by a feedback control mechanism based on laser interference fringe monitoring. The structure of the tandem FP, feedback control system, automatic parallelism adjustment mechanism and wavelength synchronization mechanism are described in detail. For experiments, a hollow cathode discharge tube of a pulse discharge type is employed. Measurements are made to determine the effects of pulse width on the 238 U peak height of 502.7 nm line, recorder traces of 235 U and 238 U lines, half width for 238 U component of the 502.7 nm line, SN ratio, reproducibility of the 235 U/ 238 U peak height ratio and 235 U/ 238 U intensity ratio. Considerations are made on the spectral line width, contrast, transmission factor, and stability of automatic parallelism control and wavelength synchronization. Results obtained indicates that a single-type interferometer would serve adequately for measuring the 235 U/ 238 U ratio if the automatic parallelism control developed here is used. The ultimate object of the tandem system is to make measurement of 236 U. Satisfactory results have not obtained as yet, but most likely the present system would make it possible if a light source of a higher intensity and advanced photometric techniques are developed. (Nogami, K.)

  8. ORNL 25 MV tandem accelerator control system

    Juras, R.C.; Biggerstaff, J.A.; Hoglund, D.E.

    1985-01-01

    The CAMAC-based control system for the 25 MV tandem electrostatic accelerator of the Holifield Heavy Ion Research Facility at Oak Ridge National Laboratory (ORNL) was specified by ORNL and built by the National Electrostatics Corporation. Two Perkin-Elmer 32-bit minicomputers are used in the system, a message switching computer and a supervisory computer. The message switching computer transmits and receives control information on six serial highways. This computer shares memory with the supervisory computer. Operator consoles are located on a serial highway; control is by means of a console CRT, trackball, and assignable shaft encoders and meters. Two identical consoles operate simultaneously: one is located in the tandem control room; the other is located in the cyclotron control room to facilitate operation during injection of tandem beams into the cyclotron or when beam lines under control of the cyclotron control system are used. The supervisory computer is used for accelerator parameter setup calculations, actual accelerator setup for new beams based on scaled, recorded parameters from previously run beams, and various other functions. Nearly seven years of control system operation and improvements will be discussed

  9. Thermodynamic characterization of tandem mismatches found in naturally occurring RNA

    Christiansen, Martha E.; Znosko, Brent M.

    2009-01-01

    Although all sequence symmetric tandem mismatches and some sequence asymmetric tandem mismatches have been thermodynamically characterized and a model has been proposed to predict the stability of previously unmeasured sequence asymmetric tandem mismatches [Christiansen,M.E. and Znosko,B.M. (2008) Biochemistry, 47, 4329–4336], experimental thermodynamic data for frequently occurring tandem mismatches is lacking. Since experimental data is preferred over a predictive model, the thermodynamic parameters for 25 frequently occurring tandem mismatches were determined. These new experimental values, on average, are 1.0 kcal/mol different from the values predicted for these mismatches using the previous model. The data for the sequence asymmetric tandem mismatches reported here were then combined with the data for 72 sequence asymmetric tandem mismatches that were published previously, and the parameters used to predict the thermodynamics of previously unmeasured sequence asymmetric tandem mismatches were updated. The average absolute difference between the measured values and the values predicted using these updated parameters is 0.5 kcal/mol. This updated model improves the prediction for tandem mismatches that were predicted rather poorly by the previous model. This new experimental data and updated predictive model allow for more accurate calculations of the free energy of RNA duplexes containing tandem mismatches, and, furthermore, should allow for improved prediction of secondary structure from sequence. PMID:19509311

  10. Actualization of the Tandem-E N Accelerator of the Nuclear Centre of Mexico

    Villasenor S, P.; Aguilera R, E.; Aspiazu F, J.; Fernandez A, J.; Fernandez B, M.; Garcia R, B.; Lopez M, J.; Martinez Q, E.; Mendez G, B.; Moreno B, E.; Murillo O, G.; Policroniades R, R.; Ramirez T, J.; Reynoso V, R.; Varela G, A.; Vega C, J.

    2004-01-01

    In this work, the activities are described carried out to change the tubes accelerators and original resistances of the accelerator Tandem-E N of the Nuclear Center, for tubes DOWLISH and resistances again design, both donated ones for ORNL. This way same, the problem is described that imply this changes, and like it was solved by the personnel of the laboratory, without having to appeal to external services, what there is redounded in a considerable increment in the costs. In form preliminary the improvements are described observed after the rehabilitation of the Accelerator. (Author)

  11. Brief-stimulus presentations on multiform tandem schedules

    Reed, Phil

    1994-01-01

    Three experiments examined the influence of a brief stimulus (a light) on the behavior of food-deprived rats whose lever pressing on tandem schedules comprising components of different schedule types resulted in food presentation. In Experiment 1, either a tandem variable-ratio variable-interval or a tandem variable-interval variable-ratio schedule was used. The variable-interval requirement in the tandem variable-ratio variable-interval schedule was yoked to the time taken to complete the va...

  12. Flexible and fragmentable tandem photosensitive nanocrystal skins

    Akhavan, S.; Uran, C.; Bozok, B.; Gungor, K.; Kelestemur, Y.; Lesnyak, V.; Gaponik, N.; Eychmüller, A.; Demir, H. V.

    2016-02-01

    We proposed and demonstrated the first account of large-area, semi-transparent, tandem photosensitive nanocrystal skins (PNSs) constructed on flexible substrates operating on the principle of photogenerated potential buildup, which avoid the need for applying an external bias and circumvent the current-matching limitation between junctions. We successfully fabricated and operated the tandem PNSs composed of single monolayers of colloidal water-soluble CdTe and CdHgTe nanocrystals (NCs) in adjacent junctions on a Kapton polymer tape. Owing to the usage of a single NC layer in each junction, noise generation was significantly reduced while keeping the resulting PNS films considerably transparent. In each junction, photogenerated excitons are dissociated at the interface of the semi-transparent Al electrode and the NC layer, with holes migrating to the contact electrode and electrons trapped in the NCs. As a result, the tandem PNSs lead to an open-circuit photovoltage buildup equal to the sum of those of the two single junctions, exhibiting a total voltage buildup of 128.4 mV at an excitation intensity of 75.8 μW cm-2 at 350 nm. Furthermore, we showed that these flexible PNSs could be bent over 3.5 mm radius of curvature and cut out in arbitrary shapes without damaging the operation of individual parts and without introducing any significant loss in the total sensitivity. These findings indicate that the NC skins are promising as building blocks to make low-cost, flexible, large-area UV/visible sensing platforms with highly efficient full-spectrum conversion.We proposed and demonstrated the first account of large-area, semi-transparent, tandem photosensitive nanocrystal skins (PNSs) constructed on flexible substrates operating on the principle of photogenerated potential buildup, which avoid the need for applying an external bias and circumvent the current-matching limitation between junctions. We successfully fabricated and operated the tandem PNSs composed of

  13. Some new ideas for Tandem Mirror blankets

    Neef, W.S. Jr.

    1981-01-01

    The Tandem Mirror Reactor, with its cylindrical central cell, has led to numerous blanket designs taking advantage of the simple geometry. Also many new applications for fusion neutrons are now being considered. To the pure fusion electricity producers and hybrids producing fissile fuel, we are adding studies of synthetic fuel producers and fission-suppressed hybrids. The three blanket concepts presented are new ideas and should be considered illustrative of the breadth of Livermore's application studies. They are not meant to imply fully analyzed designs

  14. Tandem mirror and tokamak reactor maintainability comparison

    Zahn, H.S.

    1981-01-01

    The analysis proceeds through estimates of downtime and resources required for selected maintenance actions and optimization of the replacement fraction, availability and cost of electricity. Scheduled downtime estimates and availability goals provide a basis for determining allowable forced outage downtimes. These analyses have been conducted with the assumption of redundancy wherever feasible but without the impact of maintenance equipment outages. Annual maintenance cost estimates and availabilities for both reactors are found to be approximately equal. However, the tandem mirror reactor capital costs are higher. Reduction of these costs appears feasible with the trend of current design studies toward smaller and more accessible machines

  15. Parametric systems analysis for tandem mirror hybrids

    Lee, J.D.; Chapin, D.L.; Chi, J.W.H.

    1980-09-01

    Fusion fission systems, consisting of fissile producing fusion hybrids combining a tandem mirror fusion driver with various blanket types and net fissile consuming LWR's, have been modeled and analyzed parametrically. Analysis to date indicates that hybrids can be competitive with mined uranium when U 3 O 8 cost is about 100 $/lb., adding less than 25% to present day cost of power from LWR's. Of the three blanket types considered, uranium fast fission (UFF), thorium fast fission (ThFF), and thorium fission supressed (ThFS), the ThFS blanket has a modest economic advantage under most conditions but has higher support ratios and potential safety advantages under all conditions

  16. NSF tandem stack support structure deflection characteristics

    Cook, J.

    1979-12-01

    Results are reported of load tests carried out on the glass legs of the insulating stack of the 30 MV tandem Van de Graaff accelerator now under construction at Daresbury Laboratory. The tests to investigate the vulnerability of the legs when subjected to tensile stresses were designed to; establish the angle of rotation of the pads from which the stresses in the glass legs may be calculated, proof-test the structure and at the same time reveal any asymmetry in pad rotations or deflections, and to confirm the validity of the computer design analysis. (UK)

  17. A tandem queue with delayed server release

    Nawijn, W.M.

    1997-01-01

    We consider a tandem queue with two stations. The rst station is an s-server queue with Poisson arrivals and exponential service times. After terminating his service in the rst station, a customer enters the second station to require service at an exponential single server, while in the meantime he is blocking his server in station 1 until he completes service in station 2, whereupon the server in station 1 is released. An analysis of the generating function of the simultaneous probability di...

  18. Negative ion sources for tandem accelerator

    Minehara, Eisuke

    1980-08-01

    Four kinds of negative ion sources (direct extraction Duoplasmatron ion source, radial extraction Penniing ion source, lithium charge exchange ion source and Middleton-type sputter ion source) have been installed in the JAERI tandem accelerator. The ion sources can generate many negative ions ranging from Hydrogen to Uranium with the exception of Ne, Ar, Kr, Xe and Rn. Discussions presented in this report include mechanisms of negative ion formation, electron affinity and stability of negative ions, performance of the ion sources and materials used for negative ion production. Finally, the author will discuss difficult problems to be overcome in order to get any negative ion sufficiently. (author)

  19. Plasma confinement in the TMX tandem mirror

    Hooper, E.B. Jr.; Allen, S.L.; Casper, T.A.

    1981-01-01

    Plasma confinement in the Tandem Mirror Experiment (TMX) is described. Axially confining potentials are shown to exist throughout the central 20-cm core of TMX. Axial electron-confinement time is up to 100 times that of single-cell mirror machines. Radial transport of ions is smaller than axial transport near the axis. It has two parts at large radii: nonambipolar, in rough agreement with predictions from resonant-neoclassical transport theory, and ambipolar, observed near the plasma edge under certain conditions, accompanied by a low-frequency, m = 1 instability or strong turbulence

  20. Tandem Carbocupration/Oxygenation of Terminal Alkynes

    Zhang, Donghui; Ready, Joseph M.

    2008-01-01

    A direct and general synthesis of α-branched aldehydes and their enol derivatives is described. Carbocupration of terminal alkynes and subsequent oxygenation with lithium tert-butyl peroxide generates a metallo-enolate. Trapping with various electrophiles provides α-branched aldehydes or stereo-defined trisubstituted enol esters or silyl ethers. The tandem carbocupration/oxygenation tolerates alkyl and silyl ethers, esters and tertiary amines. The reaction is effective with organocopper complexes derived from primary, secondary and tertiary Grignard reagents and from n-butyllithium. PMID:16321021

  1. Beam trajectories through the upgraded XTU tandem

    Guan Xialing

    1988-01-01

    The paper deals with a problem applicable to all electrostatic accelerators with inclined field accelerating tubes, how the trajectory of the central beam particle is affected if one of the accelerating gaps must be shorted out due to insulator failure. For the long tube of the Legnaro XTU tandem the effect of each accelerator gap is calculated and a method of compensation either by shorting out an appropriate gap with reversed incline or by appropriately steering the beam into the entrance of the low energy tube is given. (orig.)

  2. Radioisotope detection with tandem electrostatic accelerators

    Gove, H E; Elmore, D; Ferraro, R [Rochester Univ., NY (USA). Nuclear Structure Research Lab.; Beukens, R P; Chang, K H; Kilius, L R; Lee, H W; Litherland, A E [Toronto Univ., Ontario (Canada). Dept. of Physics; Purser, K H [General Ionex Corp., Newburyport, MA (USA)

    1980-01-01

    An MP tandem Van de Graaff accelerator at the University of Rochester has been employed since May 1977 to detect /sup 14/C in terrestrial samples, /sup 36/Cl in terrestrial and extraterrestrial samples and /sup 10/Be and /sup 26/Al in samples produced by reactor and accelerator irradiation. The sample sizes ranged from about 10 to less than 1 mg and the ratio of the radioisotope to the stable isotopes approached one part in 10/sup 16/ for /sup 14/C and /sup 36/Cl and one part in 10/sup 14/ for /sup 10/Be and /sup 26/Al. /sup 14/C has been measured in a number of samples of geological and archaelogical interest. /sup 36/Cl has been measured in various groundwater samples as well as samples at Antarctic meteorites and ice. Dedicated systems for /sup 14/C dating and geological measurements based on the tandem electrostatic accelerator principle are presently under construction for laboratories in the U.S.A., U.K. and Canada.

  3. Progress in the tandem mirror program

    Fowler, T.K.; Borchers, R.R.

    1981-01-01

    Experimental results in TMX have confirmed the basic principles of the tandem-mirror concept. A center-cell particle confinement parameter eta tau approx. 10 11 cm -3 s has been obtained at ion temperatures around 100 eV, which is a hundred-fold improvement over single mirrors at the same temperatures. For TMX these results have been obtained at peak beta values in the center cell in the range 10 to 40%, not yet limited by MHD activity; and ion-cyclotron resonant heating (ICRH) in the Phaedrus tandem-mirror experiment has produced beta values approx. 25%, which is several times the ideal MHD limit for that device. In addition, it has been demonstrated that the end fan chambers of TMX simultaneously isolate the hot electrons from the end walls, provide adequate pumping and conveniently dispose of the exhaust plasma energy either by thermal deposition on the end wall or by direct conversion to electricity (at 48% efficiency in agreement with calculations). Also, evidence was obtained for inherent divertor action in TMX, presumably in part responsible for the observed low impurity level

  4. Remote maintenance of tandem mirror hybrid coils

    Dietz, L.P.

    1983-01-01

    Hybrid Coils (superconducting coils with normal conducting inserts) are being employed with increasing frequency on Tandem Mirror Devices to obtain high field strengths. The normal conducting copper inserts are short lived in comparison to their encircling superconductors. It becomes desirable, therefore, to devise design features and maintenance procedures to replace the inner normal conducting coils without simultaneously replacing the longer lived (and significantly more costly) superconducting coils. The high neutron wall loadings require that the task be accomplished by remote control. The approach is to permanently mount the coil assemblies on track mounted carriages which serve, during machine operation merely as structural supports, but during maintenance procedures as moveable transport devices. The carriages incorporate all necessary provisions to facilitate remote maintenance operations and to adjust and align the coil assemblies with respect to adjacent machine components. The vacuum vessel is severed on both sides of the hybrid coil by means of a remote cutting machine. The entire coil is transported horizontally, normal to the machine axis to a nearby repair station. Prepositioned carriage mounted repair equipment at the repair station withdraws the damaged normal coil as a single entity and inserts a preassembled spare unit. The repaired hybrid coil is reassembled to the reactor. A cost and risk effective procedure has been evolved to maintain one of the more critical components of a Tandem Mirror Machine

  5. Negotiating Multiple Identities through eTandem Learning Experiences

    Yang, Se Jeong; Yi, Youngjoo

    2017-01-01

    Much of eTandem research has investigated either linguistic or cross-cultural aspects of second language (L2) learning, but relatively little is known about issues of identity construction in an eTandem context. Situating the study within theories and research of language learner identity, we examined ways in which two adult L2 learners (a Korean…

  6. Recent improvements of the tandem facility at LNS

    Ciavola, G.; Calabretta, L.; Cuttone, G.; Gammino, S.; Raia, G.; Rifuggiato, D.; Rovelli, A.; Scuderi, V.

    1993-01-01

    The Laboratorio Nazionale del Sud (LNS) of Catania is equipped with an upgraded 15 MV SMP tandem that is going to be coupled to a k=800 superconducting cyclotron. The status of the facility and the performances of the upgraded tandem are presented. (orig.)

  7. Status report on the folded tandem ion accelerator at BARC

    Folded tandem ion accelerator; charged particle beams; voltage stability; Rutherford backscattering; ion optics; beam lines. Abstract. The folded tandem ion accelerator (FOTIA) facility set up at BARC has become operational. At present, it is used for elemental analysis studies using the Rutherford backscattering technique.

  8. High-sensitivity mass spectrometry with a tandem accelerator

    Henning, W.

    1984-01-01

    The characteristic features of accelerator mass spectrometry are discussed. A short overview is given of the current status of mass spectrometry with high-energy (MeV/nucleon) heavy-ion accelerators. Emphasis is placed on studies with tandem accelerators and on future mass spectrometry of heavier isotopes with the new generation of higher-voltage tandems

  9. Performance analysis of tandem queues with small buffers

    Vuuren, van M.; Adan, I.J.B.F.; Papadopoulos, C.T.

    2005-01-01

    In this paper we present an approximation for the performance analysis of single-server tandem queues with small buffers and generally distributed service times. The approximation is based on decomposition of the tandem queue in subsystems, the parameters of which are determined by an iterative

  10. A solution process for inverted tandem solar cells

    Larsen-Olsen, Thue Trofod; Bundgaard, Eva; Sylvester-Hvid, Kristian O.

    2011-01-01

    Tandem solar cells with normal and inverted device geometries were prepared by a solution process. Both device types were based on the use of zinc(II)oxide as the electron transporting layer (ETL). The hole transporting layer (HTL) was either PEDOT:PSS for normal geometry tandem solar cells...... or vanadium(V)oxide in the case of inverted tandem cells. It was found that the inverted tandem solar cells performed comparable or better than the normal geometry devices, showing that the connection structure of vanadium(V)oxide, Ag nanoparticles and zinc(II)oxide functions both as a good recombination...... layer, ensuring serial connection, and as a solvent barrier, protecting the first photoactive layer from processing of the second layer. This successfully demonstrates a tandem solar cell fabrication process fully compatible with state-of-the-art solution based automated production procedures....

  11. TMX-U [Tandem Mirror Experiment-Upgrade] tandem-mirror thermal-barrier experiments

    Simonen, T.C.; Allen, S.L.; Baldwin, D.E.

    1986-01-01

    Thermal-barrier experiments have been carried out in the Tandem Mirror Experiment-Upgrade (TMX-U). Measurements of nonambipolar and ambipolar radial transport show that these transport processes, as well as end losses, can be controlled at modest densities and durations. Central-cell heating methods using ion-cyclotron heating (ICH) and neutral-beam injection have been demonstrated. Potential mesurements with recently developed methods indicate that deep thermal barriers can be established

  12. Prospects for a DD tandem mirror

    Logan, B.G.

    1977-01-01

    The possibility of burning advanced fusion fuels in a tandem mirror is considered for a catalyzed DD cycle, in which the T and 3 He reaction products from DD burn in both the solenoid and plugs are reinjected for complete burnup: 3D → p + 4 He + n + 21.6 MeV. Classical radial transport of the 4 He ash determines the steady state alpha fraction in the solenoid. Synchrotron radiation losses are minimized at high beta, such that charged particle fusion power recovered in a direct converter exceeds radiation losses by a factor greater than two. An overall system Q = 4.5 is found for one reaction example but the power output is large (3 GE(e) net) due to the low power density in the solenoid. Optimizing recirculating power cost (Q) against plug/solenoid density ratio (power density) should result in much smaller reactor size and cost

  13. Folded tandem ion accelerator facility at BARC

    Agarwal, Arun; Padmakumar, Sapna; Subrahmanyam, N.B.V.; Singh, V.P.; Bhatt, J.P.; Ware, Shailaja V.; Pol, S.S; Basu, A.; Singh, S.K.; Krishnagopal, S.; Bhagwat, P.V.

    2017-01-01

    The 5.5 MV single stage Van de Graaff (VDG) accelerator was in continuous operation at Nuclear Physics Division (NPD), Bhabha Atomic Research Centre (BARC) since its inception in 1962. During 1993-96, VDG accelerator was converted to a Folded Tandem Ion Accelerator (FOTIA). The scientists and engineers of NPD, IADD (then a part of NPD) along with several other divisions of BARC joined hands together in designing, fabrication, installation and commissioning of the FOTIA for the maximum terminal voltage of 6 MV. After experiencing the first accelerated ion beam on the target from FOTIA during April 2000, different ion species were accelerated and tested. Now this accelerator FOTIA is in continuous use for different kind of experiments

  14. Educational activities with a tandem accelerator

    Casolaro, P.; Campajola, L.; Balzano, E.; D'Ambrosio, E.; Figari, R.; Vardaci, E.; La Rana, G.

    2018-05-01

    Selected experiments in fundamental physics have been proposed for many years at the Tandem Accelerator of the University of Napoli ‘Federico II’s Department of Physics as a part of a one-semester laboratory course for graduate students. The aim of this paper is to highlight the educational value of the experimental realization of the nuclear reaction 19F(p,α)16O. With the purpose of verifying the mass-energy equivalence principle, different aspects of both classical and modern physics can be investigated, e.g. conservation laws, atomic models, nuclear physics applications to compositional analysis, nuclear cross-section, Q-value and nuclear spectroscopic analysis.

  15. Tandem mirror reactor power balance studies

    Gorker, G.E.; Perkins, L.J.

    1985-01-01

    A tandem mirror reactor (TMR) power plant balance model has been developed and is now being used as a computer aid for performing parametric studies. End-cell power injection into the plasma and the physics thermal Q are used to determine the fusion power. About 80% of the fusion power is transferred by high-energy neutrons to the blanket modules and structures. The other 20% of the fusion power in the high-energy alpha particles is used to heat the deuterium-tritium (D-T) plasma. Most of the plasma-ionized particles transfer their energy to the halo dumps and direct converters. The plant efficiency is calculated for three different system cycles: (1) the pressurized water/saturated steam cycle; (2) the superheated steam cycle; and (3) the more complex superheat/reheat cycle. There is a signficiant improvement in plant efficiency as the electrical power multiplication factor and steam cycle efficiency increases

  16. Status of tandem-mirror confinement

    Baldwin, D.E.

    1983-01-01

    Recent end-stopping experiments in TMX-Upgrade show strong plugging of the central cell by lower-density plugs, requiring both electron-cyclotron heating (ECRH) and 47 0 neutral-beam injection, consistent with the thermal-barrier concept. These experiments have low density (n 12 cm -3 ) due to inefficient ECRH power coupling. Hot-ion and hot-electron buildup are consistent with Fokker-Planck calculations. No ion-cyclotron activity is observed in the plugs; occasional electron-cyclotron activity is observed. With plugging, axial lifetimes (tau/sub parallel/ > 40 ms) are larger than radial (tau/sub perpendicular/ = 5 to 10 ms) due to observed non-ambipolar ion transport. Recent tandem-mirror theoretical activities are also surveyed

  17. Molecular ion acceleration using tandem accelerator

    Saito, Yuichi; Mizuhashi, Kiyoshi; Tajima, Satoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1996-12-01

    In TIARA compound beam radiation system, cluster beams have been produced using 3 MV tandem accelerator (9SDH-2) to supply them to various radiation on injection experiments. Till now, productions of C{sub 2-8}, Si{sub 2-4} and O{sub 2} and their accelerations up to 6 MeV have been succeeded. This study aimed at production and acceleration of B{sub 2-4} and LiF. Anion clusters were produced using the conventional ion source of cesium sputter type. The proportions of atoms, molecules and clusters elicited from the ion source were varied depending on the material`s properties and the operating conditions of ion source such as sample temperature, sputter voltage and the shape of sample. The anion clusters were accelerated toward the high voltage terminal in the center of tandem accelerator, leading to cations through losing their electrons by the collision to N{sub 2} gas in a charge conversion cell at the terminal. Positively charged cluster ions could be obtained by modulating the pressure of N{sub 2} gas. Thus, B{sub 2} (64 nA), B{sub 3} (4.4 nA) and B{sub 4} (2.7 nA) have been produced and their maximum survival probabilities were higher than those of carbon or silicon clusters. In addition, the relationship between beam current and gas pressure was investigated for Bn (n = 2-4) and LiF. (M.N.)

  18. Concurrent control system for the JAERI tandem accelerator

    Hanashima, Susumu; Shozi, Tokio; Shiozaki, Yasuo; Saito, Motoi; Oogane, Yasuo; Sekiguchi, Satoshi.

    1994-01-01

    A new control system for the JAERI tandem accelerator is constructed. The system utilizes concurrent processing technology with multiprocessor. Transputers are used both for central processor and I/O front end processors. (author)

  19. Monolithic Perovskite Silicon Tandem Solar Cells with Advanced Optics

    Goldschmidt, Jan C.; Bett, Alexander J.; Bivour, Martin; Blasi, Benedikt; Eisenlohr, Johannes; Kohlstadt, Markus; Lee, Seunghun; Mastroianni, Simone; Mundt, Laura; Mundus, Markus; Ndione, Paul; Reichel, Christian; Schubert, Martin; Schulze, Patricia S.; Tucher, Nico; Veit, Clemens; Veurman, Welmoed; Wienands, Karl; Winkler, Kristina; Wurfel, Uli; Glunz, Stefan W.; Hermle, Martin

    2016-11-14

    For high efficiency monolithic perovskite silicon tandem solar cells, we develop low-temperature processes for the perovskite top cell, rear-side light trapping, optimized perovskite growth, transparent contacts and adapted characterization methods.

  20. Argonne tandem as injector to a superconducting linac

    Yntema, J.L.; Den Hartog, P.K.; Henning, W.; Kutschera, W.

    1980-01-01

    The Argonne Tandem uses Pelletron chains, NEC accelerator tubes, and a dual closed-corona system. Its main function is to be an injector for a superconducting linear accelerator. As long as the transverse and longitudinal emittances are within the acceptance of the linac, the output beam quality of the tandem-linac system is essentially determined by the tandem. The sensitivity of the linac to the longitudinal emittance ΔEΔt of the incident beam makes the output beam quality dependent on the negative-ion velocity distribution in the source, transit-time effects in the tandem, molecular-beam dissociation, and stripper-foil uniformity. This paper discusses these beam-degrading effects

  1. Design of tandem mirror reactors with thermal barriers

    Carlson, G.A.

    1980-01-01

    End-plug technologies for tandem mirror reactors include high-field superconducting magnets, neutral beam injectors, and gyrotrons for electron cyclotron resonant heating (ECRH). In addition to their normal use for sustenance of the end-plug plasmas, neutral beam injectors are used for ''pumping'' trapped ions from the thermal barrier regions by charge exchange. An extra function of the axially directed pump beams is the removal of thermalized alpha particles from the reactor. The principles of tandem mirror operation with thermal barriers will be demonstrated in the upgrade of the Tandem Mirror Experiment (TMX-U) in 1981 and the tandem configuration of the Mirror fusion Test Facility (MFTF-B) in 1984

  2. Green oxidations: Titanium dioxide induced tandem oxidation coupling reactions

    Jeena, Vineet; Robinson, Ross S

    2009-01-01

    Summary The application of titanium dioxide as an oxidant in tandem oxidation type processes is described. Under microwave irradiation, quinoxalines have been synthesized in good yields from the corresponding ?-hydroxyketones.

  3. Tandem Wittig-ene reaction approach to kainic acid

    Majik, M.S.; Parameswaran, P.S.; Tilve, S.G.

    The first example of a tandem Wittig-intramolecular ene reaction approach and its application toward the synthesis of kainic acid is reported. The synthetic pathway involves conversion of prenyl bromide into phosphorane 3, followed by one-pot Wittig...

  4. Solution-Processed Nanocrystal Quantum Dot Tandem Solar Cells

    Choi, Joshua J.; Wenger, Whitney N.; Hoffman, Rachel S.; Lim, Yee-Fun; Luria, Justin; Jasieniak, Jacek; Marohn, John A.; Hanrath, Tobias

    2011-01-01

    Solution-processed tandem solar cells created from nanocrystal quantum dots with size-tuned energy levels are demonstrated. Prototype devices featuring interconnected quantum dot layers of cascaded energy gaps exhibit IR sensitivity and an open circuit voltage, V oc, approaching 1 V. The tandem solar cell performance depends critically on the optical and electrical properties of the interlayer. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Zinc Mediated Tandem Fragmentation-Allylation of Methyl 5-Iodopentofuranosides

    Hyldtoft, Lene; Madsen, Robert

    1999-01-01

    In the presence of zinc and allyl bromide methyl 5-iodopentofuranosides undergo a tandem fragmentation alkylation to give functionalized dienes. These can undergo ring-closing olefin metathesis to produce cyclohexenes which on dihydroxylation give quercitols.......In the presence of zinc and allyl bromide methyl 5-iodopentofuranosides undergo a tandem fragmentation alkylation to give functionalized dienes. These can undergo ring-closing olefin metathesis to produce cyclohexenes which on dihydroxylation give quercitols....

  6. Solution-Processed Nanocrystal Quantum Dot Tandem Solar Cells

    Choi, Joshua J.

    2011-06-03

    Solution-processed tandem solar cells created from nanocrystal quantum dots with size-tuned energy levels are demonstrated. Prototype devices featuring interconnected quantum dot layers of cascaded energy gaps exhibit IR sensitivity and an open circuit voltage, V oc, approaching 1 V. The tandem solar cell performance depends critically on the optical and electrical properties of the interlayer. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The pressure vessel for the NSF tandem

    Jones, C.W.

    1979-04-01

    The pressure vessel is a major component of the 30 MV tandem Van de Graaff electrostatic accelerator to be used in nuclear structure research at Daresbury Laboratory. The accelerator will be capable of accelerating the full range of ions in the form of a beam. Acceleration takes place in a vertical evacuated tube (beam tube) by means of a high potential on a terminal at the central position, the terminal and beam tube assembly being supported by an insulated stack structure within the pressure vessel. Under operating conditions the vessel is filled with sulphur hexafluoride gas (SF 6 ) at high pressure which acts as an insulating medium between the centre terminal and the vessel wall. The vessel is situated inside a concrete tower which besides supporting the injector room above the vessel also acts as radiation shielding around the accelerator. The report covers: functional requirements; fundamental considerations with regard to the design and procurement; detail design; materials; manufacture; acceptance test; surface treatment; final leak test. (U.K.)

  8. Short tandem repeat analysis in Japanese population.

    Hashiyada, M

    2000-01-01

    Short tandem repeats (STRs), known as microsatellites, are one of the most informative genetic markers for characterizing biological materials. Because of the relatively small size of STR alleles (generally 100-350 nucleotides), amplification by polymerase chain reaction (PCR) is relatively easy, affording a high sensitivity of detection. In addition, STR loci can be amplified simultaneously in a multiplex PCR. Thus, substantial information can be obtained in a single analysis with the benefits of using less template DNA, reducing labor, and reducing the contamination. We investigated 14 STR loci in a Japanese population living in Sendai by three multiplex PCR kits, GenePrint PowerPlex 1.1 and 2.2. Fluorescent STR System (Promega, Madison, WI, USA) and AmpF/STR Profiler (Perkin-Elmer, Norwalk, CT, USA). Genomic DNA was extracted using sodium dodecyl sulfate (SDS) proteinase K or Chelex 100 treatment followed by the phenol/chloroform extraction. PCR was performed according to the manufacturer's protocols. Electrophoresis was carried out on an ABI 377 sequencer and the alleles were determined by GeneScan 2.0.2 software (Perkin-Elmer). In 14 STRs loci, statistical parameters indicated a relatively high rate, and no significant deviation from Hardy-Weinberg equilibrium was detected. We apply this STR system to paternity testing and forensic casework, e.g., personal identification in rape cases. This system is an effective tool in the forensic sciences to obtain information on individual identification.

  9. Engineering problems of tandem-mirror reactors

    Moir, R.W.; Barr, W.L.; Boghosian, B.M.

    1981-01-01

    We have completed a comparative evaluation of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axi-cell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axi-cell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability. This paper discusses some of the many engineering problems facing the designer. We estimated the direct cost to be 2$/W/sub e/. Assuming total (direct and indirect) costs to be twice this number, we need to reduce total costs by factors between 1.7 and 2.3 to compete with future LWRs levelized cost of electricity. These reductions may be possible by designing magnets producing over 20T made possible by use of combinations of superconducting and normal conducting coils as well as improvements in performance and cost of neutral beam and microwave power systems. Scientific and technological understanding and innovation are needed in the area of thermal barrier pumping - a process by which unwanted particles are removed (pumped) from certain regions of velocity and real space in the end plug. Removal of exhaust fuel ions, fusion ash and impurities by action of a halo plasma and plasma dump in the mirror end region is another challenging engineering problem discussed in this paper

  10. Preliminary design of a tandem mirror reactor

    Strohmayer, J.N.

    1984-04-01

    The purpose of this thesis is to examine the TARA mirror experiment as a possible tandem mirror reactor configuration. This is a preliminary study to size the coil structure based on using the smallest end cell axial length that physics and engineering allow, zeroing the central cell parallel currents and having interchange stability. The input powers are estimated for the final reactor design so a Q value may be estimated. The Q value is defined as the fusion power divided by the total injected power absorbed by the plasma. A computer study was performed on the effect of the transition size, the transition vertical spacing and transition current. These parameters affect the central cell parallel currents, the recircularization of the flux tube and the ratio of central cell beta to anchor beta needed for marginal stability. Two designs were identified. The first uses 100 keV and 13 keV neutral beams to pump the ions that trap in the thermal barrier. The Q value of this reactor is 11.3. The second reactor uses a pump beam at 40 keV. This energy is chosen because there is a resonance for the charge exchange cross section between D 0 and He 2+ at this energy, thus the alpha ash will be pumped along with the deuterium and tritium. The Q value of this reactor is 11.6

  11. Transcription of tandemly repetitive DNA: functional roles.

    Biscotti, Maria Assunta; Canapa, Adriana; Forconi, Mariko; Olmo, Ettore; Barucca, Marco

    2015-09-01

    A considerable fraction of the eukaryotic genome is made up of satellite DNA constituted of tandemly repeated sequences. These elements are mainly located at centromeres, pericentromeres, and telomeres and are major components of constitutive heterochromatin. Although originally satellite DNA was thought silent and inert, an increasing number of studies are providing evidence on its transcriptional activity supporting, on the contrary, an unexpected dynamicity. This review summarizes the multiple structural roles of satellite noncoding RNAs at chromosome level. Indeed, satellite noncoding RNAs play a role in the establishment of a heterochromatic state at centromere and telomere. These highly condensed structures are indispensable to preserve chromosome integrity and genome stability, preventing recombination events, and ensuring the correct chromosome pairing and segregation. Moreover, these RNA molecules seem to be involved also in maintaining centromere identity and in elongation, capping, and replication of telomere. Finally, the abnormal variation of centromeric and pericentromeric DNA transcription across major eukaryotic lineages in stress condition and disease has evidenced the critical role that these transcripts may play and the potentially dire consequences for the organism.

  12. Analysis of tandem mirror reactor performance

    Wu, K.F.; Campbell, R.B.; Peng, Y.K.M.

    1984-11-01

    Parametric studies are performed using a tandem mirror plasma point model to evaluate the wall loading GAMMA and the physics figure of merit, Q (fusion power/injected power). We explore the relationship among several dominant parameters and determine the impact on the plasma performance of electron cyclotron resonance heating in the plug region. These global particle and energy balance studies were carried out under the constraints of magnetohydrodynamic (MHD) equilibrium and stability and constant magnetic flux, assuming a fixed end-cell geometry. We found that the higher the choke coil fields, the higher the Q, wall loading, and fusion power due to the combination of the increased central-cell field B/sub c/ and density n/sub c/ and the reduced central-cell beta β/sub c/. The MHD stability requirement of constant B/sub c/ 2 β/sub c/ causes the reduction in β/sub c/. In addition, a higher value of fusion power can also be obtained, at a fixed central-cell length, by operating at a lower value of B/sub c/ and a higher value of β/sub c/

  13. Tandem mass spectrometry: analysis of complex mixtures

    Singleton, K.E.

    1985-01-01

    Applications of tandem mass spectrometry (MS/MS) for the analysis of complex mixtures results in increased specificity and selectivity by using a variety of reagent gases in both negative and positive ion modes. Natural isotopic abundance ratios were examined in both simple and complex mixtures using parent, daughter and neutral loss scans. MS/MS was also used to discover new compounds. Daughter scans were used to identify seven new alkaloids in a cactus species. Three of these alkaloids were novel compounds, and included the first simple, fully aromatic isoquinoline alkaloids reported in Cactaceae. MS/MS was used to characterize the chemical reaction products of coal in studies designed to probe its macromolecular structure. Negative ion chemical ionization was utilized to study reaction products resulting from the oxidation of coal. Possible structural units in the precursor coal were predicted based on the reaction products identified, aliphatic and aromatic acids and their anhydrides. The MS/MS method was also used to characterize reaction products resulting from coal liquefaction and/or extraction. These studies illustrate the types of problems for which MS/MS is useful. Emphasis has been placed on characterization of complex mixtures by selecting experimental parameters which enhance the information obtained. The value of using MS/MS in conjunction with other analytical techniques as well as the chemical pretreatment is demonstrated

  14. Results from the Tara tandem mirror experiment

    Lane, B.G.

    1987-09-01

    A summary of the experimental results from the Tara tandem mirror experiment is presented. Optimization of the fueling configuration, slow wave ion cyclotron heating from a magnetic ''plateau'' using an aperture antenna design, and enhanced stabilization from a magnetic divertor have allowed the attainment of a stable start up plasma (T/sub i,perpendicular/ = 800 - 1500 eV, n/sub e/ = 4 - 5 x 10 12 cm -3 , T/sub e/ = 70 - 80 eV). Plugging experiments using radiofrequency waves near the plug midplane ion cyclotron frequency have proved successful in reducing endloss, while simultaneously leading to an increase in central cell density. The plugging potentials have been limited to approximately the ion parallel temperature. This limitation is due to low frequency instabilities localized in the plug. Axial plugging experiments using electron cyclotron (ECH) resonant microwave radiation in the plug cells have had ambiguous results. Endloss reductions up to 100% have been achieved without build-up of central cell densities or the appearance of the reflected particles at the other end of the machine. We conjecture that rapid radial losses accompany the use of ECH, although the mechanisms for this loss remain unidentified. 9 refs., 9 figs

  15. Software dependability in the Tandem GUARDIAN system

    Lee, Inhwan; Iyer, Ravishankar K.

    1995-01-01

    Based on extensive field failure data for Tandem's GUARDIAN operating system this paper discusses evaluation of the dependability of operational software. Software faults considered are major defects that result in processor failures and invoke backup processes to take over. The paper categorizes the underlying causes of software failures and evaluates the effectiveness of the process pair technique in tolerating software faults. A model to describe the impact of software faults on the reliability of an overall system is proposed. The model is used to evaluate the significance of key factors that determine software dependability and to identify areas for improvement. An analysis of the data shows that about 77% of processor failures that are initially considered due to software are confirmed as software problems. The analysis shows that the use of process pairs to provide checkpointing and restart (originally intended for tolerating hardware faults) allows the system to tolerate about 75% of reported software faults that result in processor failures. The loose coupling between processors, which results in the backup execution (the processor state and the sequence of events) being different from the original execution, is a major reason for the measured software fault tolerance. Over two-thirds (72%) of measured software failures are recurrences of previously reported faults. Modeling, based on the data, shows that, in addition to reducing the number of software faults, software dependability can be enhanced by reducing the recurrence rate.

  16. Actualization of the Tandem-E N Accelerator of the Nuclear Centre of Mexico; Actualizacion del Acelerador Tandem-EN del Centro Nuclear

    Villasenor S, P.; Aguilera R, E.; Aspiazu F, J.; Fernandez A, J.; Fernandez B, M.; Garcia R, B.; Lopez M, J.; Martinez Q, E.; Mendez G, B.; Moreno B, E.; Murillo O, G.; Policroniades R, R.; Ramirez T, J.; Reynoso V, R.; Varela G, A.; Vega C, J. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    In this work, the activities are described carried out to change the tubes accelerators and original resistances of the accelerator Tandem-E N of the Nuclear Center, for tubes DOWLISH and resistances again design, both donated ones for ORNL. This way same, the problem is described that imply this changes, and like it was solved by the personnel of the laboratory, without having to appeal to external services, what there is redounded in a considerable increment in the costs. In form preliminary the improvements are described observed after the rehabilitation of the Accelerator. (Author)

  17. The impact of genome triplication on tandem gene evolution in Brassica rapa

    Lu eFang

    2012-11-01

    Full Text Available Whole genome duplication (WGD and tandem duplication (TD are both important modes of gene expansion. However, how whole genome duplication influences tandemly duplicated genes is not well studied. We used Brassica rapa, which has undergone an additional genome triplication (WGT and shares a common ancestor with Arabidopsis thaliana, Arabidopsis lyrata and Thellungiella parvula, to investigate the impact of genome triplication on tandem gene evolution. We identified 2,137, 1,569, 1,751 and 1,135 tandem gene arrays in B. rapa, A. thaliana, A. lyrata and T. parvula respectively. Among them, 414 conserved tandem arrays are shared by the 3 species without WGT, which were also considered as existing in the diploid ancestor of B. rapa. Thus, after genome triplication, B. rapa should have 1,242 tandem arrays according to the 414 conserved tandems. Here, we found 400 out of the 414 tandems had at least one syntenic ortholog in the genome of B. rapa. Furthermore, 294 out of the 400 shared syntenic orthologs maintain tandem arrays (more than one gene for each syntenic hit in B. rapa. For the 294 tandem arrays, we obtained 426 copies of syntenic paralogous tandems in the triplicated genome of B. rapa. In this study, we demonstrated that tandem arrays in B. rapa were dramatically fractionated after WGT when compared either to non-tandem genes in the B. rapa genome or to the tandem arrays in closely related species that have not experienced a recent whole-genome polyploidization event.

  18. The design and numerical analysis of tandem thermophotovoltaic cells

    Yang Hao-Yu; Liu Ren-Jun; Wang Lian-Kai; Lü You; Li Tian-Tian; Li Guo-Xing; Zhang Yuan-Tao; Zhang Bao-Lin

    2013-01-01

    In this paper, numerical analysis of GaSb =(E g = 0.72 eV)/Ga 0.84 In 0.16 As 0.14 Sb 0.86 (E g = 0.53 eV) tandem thermophotovoltaic (TPV) cells is carried out by using Silvaco/Atlas software. In the tandem cells, a GaSb p-n homojunction is used for the top cell and a GaInAsSb p-n homojunction for the bottom cell. A heavily doped GaSb tunnel junction connects the two sub-cells together. The simulations are carried out at a radiator temperature of 2000 K and a cell temperature of 300 K. The radiation photons are injected from the top of the tandem cells. Key properties of the single- and dual-junction TPV cells, including I–V characteristic, maximum output power (P max ), open-circuit voltage (V oc ), short-circuit current (I sc ), etc. are presented. The effects of the sub-cell thickness and carrier concentration on the key properties of tandem cells are investigated. A comparison of the dual-TPV cells with GaSb and GaInAsSb single junction cells shows that the P max of tandem cells is almost twice as great as that of the single-junction cells. (interdisciplinary physics and related areas of science and technology)

  19. Telemetry component tests in the FN tandem terminal

    Bicek, J.J.; Billquis, P.J.; Yntema, J.L.

    1977-01-01

    When an electrostatic tandem accelerator is used primarily for heavy ion acceleration, numerous communication channels with the high voltage terminal are desirable. The ANL FN tandem operates at a tank pressure of 100 psi SF 6 at terminal voltages up to 9.5 MeV. A low powered He-Ne laser with 15 percent modulation has been successfully tested in the terminal under normal operating conditions. Such a system allows the transmission of information without the use of light guides. Multistranded light guides did not withstand voltage gradients as low as 0.4 MV/m. Single core light guides with a diameter of 0.5 mm have been successfully operated at voltage gradients in excess of 1.7 MV/m. In addition to the laser a microprocessor has also been tested in the tandem terminal. With suitable protection, an 8080 microprocessor and a programmable ROM operated successfully for several weeks under normal operating conditions

  20. Optical klystron FELs based on tandem electrostatic accelerators

    Gover, A.; Friedman, A.

    1989-01-01

    The operation of tandem electrostatic accelerator FELs in an optical klystron configuration makes it possible to take advantage of the high quality (low emittance and low energy spread) of the electron beam in electrostatic accelerators. With evolving microwiggler technology, state-of-the-art moderate energy (6-14-MeV) tandem electrostatic accelerators may be used for the development of highly coherent tunable radiation sources in the entire IR region. The authors present the general design considerations and the predicted operating characteristics of such devices and refer in specifics to a design of a 10-1000-μm FEL based on the parameters of a 5-6-MeV high current tandem accelerator. The operating wavelength of FELs is determined by the Doppler shift formula

  1. Study of Tandem Accelerator Technology and Its Prospects

    Sigit-Hariyanto; Sudjatmoko; Djoko-S-Pudjorahardjo; Suryadi; Widdi-Usada; Suprapto; Djasiman; Tono-Wibowo; Agus-Purwadi

    2000-01-01

    Tandem accelerator is an ion acceleration tool in which negative ions injected in the accelerator tube and stripped to become positive ions, then accelerated by electrostatic high voltage such that its energy is multiplied. In this paper, we describe the prospect of accelerator application briefly in agriculture and biotechnology, industry, health and medicine, environment fields. Technical study on tandem accelerator included SNICS and alphatross ion sources, acceleration system and stripper system. The study result for many kinds of negative ions and its current which should be injected in the accelerator tube and the output of tandem accelerator H + , and the distribution of C + , Ni + , Au + , Br + ion on varying charge state is shown. (author)

  2. Tandem photovoltaic solar cells and increased solar energy conversion efficiency

    Loferski, J. J.

    1976-01-01

    Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

  3. Technical specification for a 25 MV tandem electrostatic accelerator

    Jones, C.M.; Biggerstaff, J.A.; Blair, J.K.; Ball, J.B.; Larson, J.D.; Martin, J.A.; McConnell, J.W.; Milner, W.T.; Murray, J.A.; Ziegler, N.F.

    1975-08-01

    Specifications are given for an accelerator system to consist of a 25 MV tandem electrostatic accelerator and specified ancillary equipment, including an injector, a beam transport system, a vacuum system, a control system, and a system for storage of the insulating gas and transport of the gas to and from the accelerator. The insulating gas shall be SF 6 . The tandem electrostatic accelerator shall be vertical in orientation and of folded construction, and shall be installed in a new structure adjacent to the Oak Ridge Isochronous Cyclotron. (auth)

  4. New uses for the Tandem Van de Graaff Accelerator

    Balcazar Garcia, M.

    1989-01-01

    The Tandem Van de Graaff is a very high resolution magnetic separator whose application offers a rich and virgin field for research in other areas. This work presents some of the radioisotopes of interest; their mechanisms of formation and this relationship with studies in solar activity variations in earth magnetic fields, carbon cycle dynamics, archaeological dating, dating of aquifer deposits, solar influences on variations in earth climates and the mechanics of tectonic plates. Discussed are the advantages of the Tandem utilization as an isotope separator compared with conventional techniques. (Author)

  5. Overview and direction in the tandem mirror program

    Thomassen, K.I.

    1983-04-01

    There are two main thrusts to the tandem mirror program at the present time. One is to gather the experimental data base to verify the axicell thermal-barrier concept and the other to improve the end plugs for tandems. With such improvements one might approach the ideal fusion reactor, a simple solenoid of modular elements whose ends are but a modest perturbation on the configuration from both a cost and technological viewpoint. Progress toward these two goals is discussed here, and the directions to be taken in the immediate future are described

  6. Axisymmetric tandem mirror stabilized by a magnetic limiter

    Kesner, J.; Post, R.S.; Lane, B.

    1985-06-01

    In order to stabilize MHD-like, fast growing m = 1 fluctuations in the central cell of a tandem mirror we propose the introduction of a magnetic limiter. The magnetic limiter would create a ring null in the magnetic field. Electrons which enter the null can stream azimuthally and thereby ''short-circuit'' m = 1 fluctuations. Some pressure could be maintained on the separatrix flux surface by locating the null on a local magnetic maxima or by axial plugging. This scheme introduces the possibility of a fully axisymmetric tandem mirror

  7. Ohio University tandem Van de Graaff accelerator. Final report

    Lane, R.O.

    1977-11-01

    A summary is given of the work carried out at the John Edwards Tandem Accelerator Laboratory of Ohio University during the period 1970 to 1977 on studies of neutron-nucleus interactions and nuclear structure using neutrons as probes. This work utilizes the main and unique characteristic of the accelerator: high current, high voltage tandem. Certain applied areas were also studied, such as the production of short-lived isotopes for use in medical diagnoses, production of very high neutron intensity to observe possible sputtering effects, and proton induced x-ray emission with a microprobe beam

  8. Dinuclear Tetrapyrazolyl Palladium Complexes Exhibiting Facile Tandem Transfer Hydrogenation/Suzuki Coupling Reaction of Fluoroarylketone

    Dehury, Niranjan; Maity, Niladri; Tripathy, Suman Kumar; Basset, Jean-Marie; Patra, Srikanta

    2016-01-01

    Herein, we report an unprecedented example of dinuclear pyrazolyl-based Pd complexes exhibiting facile tandem catalysis for fluoroarylketone: Tetrapyrazolyl di-palladium complexes with varying Pd-Pd distances efficiently catalyze the tandem reaction

  9. Hybrid tandem quantum dot/organic photovoltaic cells with complementary near infrared absorption

    Kim, Taesoo; Palmiano, Elenita; Liang, Ru-Ze; Hu, Hanlin; Banavoth, Murali; Kirmani, Ahmad R.; Firdaus, Yuliar; Gao, Yangqin; Sheikh, Arif D.; Yuan, Mingjian; Mohammed, Omar F.; Hoogland, Sjoerd; Beaujuge, Pierre; Sargent, Edward H.; Amassian, Aram

    2017-01-01

    Monolithically integrated hybrid tandem solar cells that effectively combine solution-processed colloidal quantum dot (CQD) and organic bulk heterojunction subcells to achieve tandem performance that surpasses the individual subcell efficiencies

  10. Tandem neopentyl glycol maltosides (TNMs) for membrane protein stabilisation†

    Bae, Hyoung Eun; Mortensen, Jonas S.; Ribeiro, Orquidea; Du, Yang; Ehsan, Muhammad; Kobilka, Brian K.; Loland, Claus J.; Byrne, Bernadette; Chae, Pil Seok

    2016-01-01

    A novel class of detergents, designated tandem neopentyl glycol maltosides (TNMs), were evaluated with four target membrane proteins. The best detergent varied depending on the target, but TNM-C12L and TNM-C11S were notable for their ability to confer increased membrane protein stability compared to DDM. These agents have potential for use in membrane protein research.

  11. Tandem neopentyl glycol maltosides (TNMs) for membrane protein stabilisation.

    Bae, Hyoung Eun; Mortensen, Jonas S; Ribeiro, Orquidea; Du, Yang; Ehsan, Muhammad; Kobilka, Brian K; Loland, Claus J; Byrne, Bernadette; Chae, Pil Seok

    2016-10-04

    A novel class of detergents, designated tandem neopentyl glycol maltosides (TNMs), were evaluated with four target membrane proteins. The best detergent varied depending on the target, but TNM-C12L and TNM-C11S were notable for their ability to confer increased membrane protein stability compared to DDM. These agents have potential for use in membrane protein research.

  12. Tandem neopentyl glycol maltosides (TNMs) for membrane protein stabilisation†

    Bae, Hyoung Eun; Mortensen, Jonas S.; Ribeiro, Orquidea; Du, Yang; Ehsan, Muhammad; Kobilka, Brian K.; Loland, Claus J.; Byrne, Bernadette

    2017-01-01

    A novel class of detergents, designated tandem neopentyl glycol maltosides (TNMs), were evaluated with four target membrane proteins. The best detergent varied depending on the target, but TNM-C12L and TNM-C11S were notable for their ability to confer increased membrane protein stability compared to DDM. These agents have potential for use in membrane protein research. PMID:27711401

  13. Tandem neopentyl glycol maltosides (TNMs) for membrane protein stabilisation

    Bae, Hyoung Eun; Mortensen, Jonas S; Ribeiro, Orquidea

    2016-01-01

    A novel class of detergents, designated tandem neopentyl glycol maltosides (TNMs), were evaluated with four target membrane proteins. The best detergent varied depending on the target, but TNM-C12L and TNM-C11S were notable for their ability to confer increased membrane protein stability compared...

  14. Accelerator mass analysis at tandem accelerator in Kyoto University

    Nakamura, Masanobu; Tazawa, Yuji; Matsumoto, Hiroshi; Hirose, Masanori [Kyoto Univ. (Japan). Faculty of Science; Ogino, Koya; Kohno, Masuchika; Funaba, Hiroyuki

    1996-12-01

    Tandem accelerator in Science Faculty, Kyoto University was renewed from 5 MV in the highest terminal voltage of Van de Graaff to 8 MV of Peletron in 1992. And, AMS effective for cosmic ray, dating, environment measurement and so forth is determined to a column of collaborative studies by universities and institutes in Japan. On this renewal, because of using high energy beam transportation of the present tandem accelerator, super high sensitivity measurement of long half-life radioactive isotopes of heavy elements such as {sup 36}Cl, {sup 41}Ca, {sup 129}I and so forth is aimed, although having some limitations due to small magnet. The accelerator is active in characteristics of the middle size tandem accelerator, and developing {sup 14}C measurement for its standard technology, as aiming at {sup 36}Cl measurement, at first. As a result, in this tandem accelerator stable and high beam transmittance could be obtained by adding a slit at negative ion source to make emittance of incident beam smaller. {sup 14}C/{sup 12}C ratio of Modan`s sample obtained by graphitizing NBS oxalic acid and Ded`s sample consisting of mineral graphite produced in Sri Lanka are measured to confirm better reproductivity of this system. Future development of successive incident method is planned to test actual carbon samples. (G.K.)

  15. Note on a tandem queue with delayed server release

    Nawijn, W.M.

    2000-01-01

    We consider a tandem queue with two stations. The first station is an $s$-server queue with Poisson arrivals and exponential service times. After terminating his service in the first station, a customer enters the second station to require service at a single server, while in the meantime he is

  16. Finding all sorting tandem duplication random loss operations

    Bernt, Matthias; Chen, Kuan Yu; Chen, Ming Chiang

    2011-01-01

    A tandem duplication random loss (TDRL) operation duplicates a contiguous segment of genes, followed by the random loss of one copy of each of the duplicated genes. Although the importance of this operation is founded by several recent biological studies, it has been investigated only rarely from...

  17. Y-Chromosome short tandem repeat, typing technology, locus ...

    Aghomotsegin

    2015-07-08

    Jul 8, 2015 ... Y-Chromosome short tandem repeat, typing technology, locus information and allele frequency in different population: A review. Muhanned Abdulhasan Kareem1, Ameera Omran Hussein2 and Imad Hadi Hameed2*. 1Babylon University, Centre of Environmental Research, Hilla City, Iraq. 2Department of ...

  18. Genetic Analysis of Eight X-Chromosomal Short Tandem Repeat ...

    X-Chromosome short tandem repeat (STR) typing can complement existing DNA profiling protocols and can also offer useful information in cases of complex kinship analysis. This is the first population study of 8 X-linked STRs in Iraq. The purpose of this work was to provide a basic data of allele and haplotype frequency for ...

  19. X-Chromosome short tandem repeat, advantages and typing ...

    Microsatellites of the X-chromosome have been increasingly studied in recent years as a useful tool in forensic analysis. This review describes some details of X-chromosomal short tandem repeat (STR) analysis. Among them are: microsatellites, amplification using polymerase chain reaction (PCR) of STRs, PCR product ...

  20. Near-optimal switching strategies for a tandem queue

    van Leeuwen, D.; Núñez-Queija, R.; Boucherie, R.J.; van Dijk, N.M.

    2017-01-01

    Motivated by various applications in logistics, road traffic and production management, we investigate two versions of a tandem queueing model in which the service rate of the first queue can be controlled. The objective is to keep the mean number of jobs in the second queue as low as possible,

  1. Near-optimal switching strategies for a tandem queue

    D. van Leeuwen (Daphne); R. Núñez Queija (Rudesindo)

    2017-01-01

    textabstractMotivated by various applications in logistics, road traffic and production management, we investigate two versions of a tandem queueing model in which the service rate of the first queue can be controlled. The objective is to keep the mean number of jobs in the second queue as low as

  2. Ultimate performance of polymer: Fullerene bulk heterojunction tandem solar cells

    Kotlarski, J.D.; Blom, P.W.M.

    2011-01-01

    We present the model calculations to explore the potential of polymer:fullerene tandem solar cells. As an approach we use a combined optical and electrical device model, where the absorption profiles are used as starting point for the numerical current-voltage calculations. With this model a maximum

  3. Analysis of posttranslational modifications of proteins by tandem mass spectrometry

    Larsen, Martin Røssel; Trelle, Morten B; Thingholm, Tine E

    2006-01-01

    -temporal distribution in cells and tissues. Most PTMs can be detected by protein and peptide analysis by mass spectrometry (MS), either as a mass increment or a mass deficit relative to the nascent unmodified protein. Tandem mass spectrometry (MS/MS) provides a series of analytical features that are highly useful...

  4. Beam transport calculations for the EN tandem installation

    Sparks, R.J.

    1980-12-01

    Transport of a charged particle beam through the new EN tandem accelerator installation of the Institute of Nuclear Sciences has been analysed using simplified mathematical models. The purpose is to identify the factors affecting transmission of the beam, and to arrive at a design for the system to inject the beam into the accelerator

  5. Biological effects of tandem shock waves demonstrated on magnetic resonance

    Beneš, J.; Zeman, J.; Poučková, P.; Zadinová, M.; Šunka, Pavel; Lukeš, Petr

    Roč. 113, č. 6 ( 2012 ), s. 335-338 ISSN 0006-9248 R&D Projects: GA ČR GA202/09/1151 Institutional research plan: CEZ:AV0Z20430508 Keywords : electrical discharges in water * focused shock waves * cavitations * tandem shock waves Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.472, year: 2012

  6. Cable systems for experimental facilities in JAERI TANDEM ACCELERATOR BUILDING

    Tukihashi, Yoshihiro; Yoshida, Tadashi; Takekoshi, Eiko

    1979-03-01

    Measuring cable systems for experimental facilities in JAERI TANDEM ACCELERATOR BUILDING were completed recently. Measures are taken to prevent penetration of noises into the measuring systems. The cable systems are described in detail, including power supplies and grounding for the measuring systems. (author)

  7. Accelerator mass spectrometry with a coupled tandem-linac system

    Kutschera, W.

    1984-01-01

    A coupled system provides higher energies, which allows one to extend AMS to hitherto untouched mass regions. Another important argument is that the complexity, although bothersome for the operation, increases the selectivity of detecting a particular isotope. The higher-energy argument holds for any heavy-ion accelerator which is capable of delivering higher energy than a tandem. The present use of tandem-linac combinations for AMS, rather than cyclotrons, linacs or combinations of these machines, has mainly to do with the fact that this technique was almost exclusively developed around tandem accelerators. Therefore the tandem-linac combination is a natural extension to higher energies. The use of negative ions has some particular advantages in suppressing background from unwanted elements that do not form stable negative ions (e.g., N, Mg, Ar). On the other hand, this limits the detection of isotopes to elements which do form negative ions. For particular problems it may therefore be advantageous to use a positive-ion machine. What really matters most for choosing one or the other machine is to what extent the entire accelerator system can be operated in a truly quantiative way from the ion source to the detection system. 20 references, 4 figures

  8. Stochastic motion of particles in tandem mirror devices

    Ichikawa, Y.H.; Kamimura, T.

    1982-01-01

    Stochastic motion of particles in tandem mirror devices is examined on basis of a nonlinear mapping of particle positions on the equatorial plane. Local stability analysis provides detailed informations on particle trajectories. The rate of stochastic plasma diffusion is estimated from numerical observations of motions of particles over a large number of time steps. (author)

  9. Concurrent control system for the JAERI tandem accelerator

    Hanashima, S.; Shoji, T.; Horie, K.; Tsukihashi, Y.

    1992-01-01

    Concurrent processing with a multiprocessor system is introduced to the particle accelerator control system region. The control system is a good application in both logical and physical aspects. A renewal plan of the control system for the JAERI tandem accelerator is discussed. (author)

  10. Characteristics of KUMM Tandem Electrostatic Accelerator 5SDH-2

    Kitamura, Akira; Furuyama, Yuichi; Taniike, Akira; Kubota, Naoyoshi

    1998-01-01

    The KUMM Tandem Electrostatic Accelerator was heavily damaged by the Hanshin Earthquake in Jan. 1995, and the renewed version 5SDH-2 was installed in 1996. The fundamental characteristics of the renewed system is reported together with the system composition. (author)

  11. Scaling of the optical parameters for the JAERI tandem accelerator

    Hanashima, S.; Minehara, E.

    1986-01-01

    A scaling rule of the beam optical parameters was adopted for computer-aided beam transport in the JAERI tandem accelerator. Tests have shown that the computer program can transport a specified beam in a short time using a reference parameter set. Problems of ion source control and accuracy of the optical devices are also discussed

  12. State-dependent importance sampling for a slowdown tandem queue

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2011-01-01

    In this paper we investigate an advanced variant of the classical (Jackson) tandem queue, viz. a two-node system with server slowdown. By this mechanism, the service speed of the upstream queue is reduced as soon as the number of jobs in the downstream queue reaches some pre-specified threshold. We

  13. A tandem queue with server slow-down and blocking

    van Foreest, N.D.; van Ommeren, Jan C.W.; Mandjes, M.R.H.; Scheinhardt, Willem R.W.

    2005-01-01

    We consider two variants of a two-station tandem network with blocking. In both variants the first server ceases to work when the queue length at the second station hits a 'blocking threshold.' In addition, in variant 2 the first server decreases its service rate when the second queue exceeds a

  14. A tandem queue with server slow-down and blocking.

    van Foreest, N.; van Ommeren, J.C.; Mandjes, M.R.H.; Scheinhardt, W.

    2005-01-01

    We consider two variants of a two-station tandem network with blocking. In both variants the first server ceases to work when the queue length at the second station hits a 'blocking threshold.' In addition, in variant 2 the first server decreases its service rate when the second queue exceeds a

  15. The nuclear structure facility tandem at Daresbury laboratory

    Voss, R.G.P.

    1976-01-01

    A 30MV tandem electrostatic accelerator for ions of all types, including heavy ions, is being built at Daresbury Laboratory. Construction is well advanced, and considerable effort is continuing to be devoted to R and D programme into the technology of electrostatic accelerators

  16. Optochemokine Tandem for Light-Control of Intracellular Ca2.

    Katrin Feldbauer

    Full Text Available An optochemokine tandem was developed to control the release of calcium from endosomes into the cytosol by light and to analyze the internalization kinetics of G-protein coupled receptors (GPCRs by electrophysiology. A previously constructed rhodopsin tandem was re-engineered to combine the light-gated Ca2+-permeable cation channel Channelrhodopsin-2(L132C, CatCh, with the chemokine receptor CXCR4 in a functional tandem protein tCXCR4/CatCh. The GPCR was used as a shuttle protein to displace CatCh from the plasma membrane into intracellular areas. As shown by patch-clamp measurements and confocal laser scanning microscopy, heterologously expressed tCXCR4/CatCh was internalized via the endocytic SDF1/CXCR4 signaling pathway. The kinetics of internalization could be followed electrophysiologically via the amplitude of the CatCh signal. The light-induced release of Ca2+ by tandem endosomes into the cytosol via CatCh was visualized using the Ca2+-sensitive dyes rhod2 and rhod2-AM showing an increase of intracellular Ca2+ in response to light.

  17. II-IV-V Based Thin Film Tandem Photovoltaic Cell

    Newman, Nathan [Arizona State Univ., Mesa, AZ (United States); van Schilfgaarde, Mark [Arizona State Univ., Mesa, AZ (United States)

    2012-10-04

    [Through a combination of theory and experiment that, absent unknown mitigating factors, a tandem cell whose (wide-gap. 1.8 eV) top layer is made of ZnSnP2 and whose (narrow gap, 1.1 eV) bottom layer consisting of ZnGeAs2 are near-ideal materials for a tandem cell. Not only are there gaps optimally adjusted to the solar spectrum, but the two compounds are lattice-matched, and their energy band structure and optical absorption are also near-ideal (they closely resemble that of GaAs). Our first major challenge is to establish that high-quality II-IV-V thin films can be synthesized. We have begun growing and characterizing films of ZnGeAs2 and ZnSnP2, initially grown on Ge substrates (the lattice constant of Ge matches these compounds) by pulsed laser ablation and sputtering. In tandem are theoretical calculations to guide the experiments. The goal is to develop methods that can be used to produce a pair of lattice-matched thin films that will be useful in tandem cells.

  18. The "Bologna-München" Tandem--Experiencing Interculturality

    De Martino, Sandro

    2016-01-01

    This case study describes the "Bologna-München" Tandem, a cross-border collaboration which began in 2011. The aim of the collaboration is to give students studying Italian at the Ludwig- Maximilians-University in Munich and students studying German at the University of Bologna the opportunity to experience interculturality through…

  19. A New Synthetic Route to Dihydrobenzopyran Via Tandem Demethylation Cyclisation

    G. Shanmugam

    2000-06-01

    Full Text Available A tandem demethylation-cyclisation reaction resulting in the formation of pyran rings using AlCl3/EtSH reagent under mild reaction conditions is reported. X-ray diffraction studies on the intermediate support the suggested mechanism.

  20. Interim report on the tandem mirror hybrid design study

    Moir, R.W.

    1979-01-01

    The initial phase of a 2-year design study of a tandem mirror fusion reactor is presented. The following chapters are included: (1) mechanical design of the plant; (2) plasma physics; (3) blanket design; (4) magnet design; (5) injector design; (6) direct convertor design; (7) balance of plant design; (8) fission burner reactor; (9) environment and safety; and (10) economic analysis

  1. State-dependent importance sampling for a Jackson tandem network

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2008-01-01

    This paper considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jacksonian two-node tandem queue – it is known that in this setting ‘traditional’ stateindependent importance-sampling distributions

  2. State-dependent importance sampling for a Jackson tandem network

    D.I. Miretskiy; W.R.W. Scheinhardt (Werner); M.R.H. Mandjes (Michel)

    2008-01-01

    htmlabstractThis paper considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jacksonian two-node tandem queue – it is known that in this setting ‘traditional’ stateindependent importance-sampling

  3. Efficient organic tandem solar cells based on small molecules

    Riede, Moritz; Widmer, Johannes; Timmreck, Ronny; Wynands, David; Leo, Karl [Institut fuer Angewandte Photophysik, Technische Universitaet Dresden, George-Baehr-Str. 1, 01069 Dresden (Germany); Uhrich, Christian; Schwartz, Gregor; Gnehr, Wolf-Michael; Hildebrandt, Dirk; Weiss, Andre; Pfeiffer, Martin [Heliatek GmbH, Treidlerstr. 3, 01139 Dresden (Germany); Hwang, Jaehyung; Sundarraj, Sudhakar; Erk, Peter [BASF SE, GVC/E-J542, 67056 Ludwigshafen (Germany)

    2011-08-23

    In this paper, two vacuum processed single heterojunction organic solar cells with complementary absorption are described and the construction and optimization of tandem solar cells based on the combination of these heterojunctions demonstrated. The red-absorbing heterojunction consists of C{sub 60} and a fluorinated zinc phthalocyanine derivative (F4-ZnPc) that leads to a 0.1-0.15 V higher open circuit voltage V{sub oc} than the commonly used ZnPc. The second heterojunction incorporates C{sub 60} and a dicyanovinyl-capped sexithiophene derivative (DCV6T) that mainly absorbs in the green. The combination of both heterojunctions into one tandem solar cell leads to an absorption over the whole visible range of the sun spectrum. Thickness variations of the transparent p-doped optical spacer between both subcells in the tandem solar cell is shown to lead to a significant change in short circuit current density j{sub sc} due to optical interference effects, whereas V{sub oc} and fill factor are hardly affected. The maximum efficiency {eta} of about 5.6% is found for a spacer thickness of 150-165 nm. Based on the optimized 165nm thick spacer, effects of intensity and angle of illumination, and temperature on a tandem device are investigated. Variations in illumination intensity lead to a linear change in j{sub sc} over three orders of magnitude and a nearly constant {eta} in the range of 30 to 310 mW cm{sup -2}. Despite the stacked heterojunctions, the performance of the tandem device is robust against different illumination angles: j{sub sc} and {eta} closely follow a cosine behavior between 0 and 70 . Investigations of the temperature behavior of the tandem device show an increase in {eta} of 0.016 percentage points per Kelvin between -20 C and 25 C followed by a plateau up to 50 C. Finally, further optimization of the tandem stack results in a certified {eta} of (6.07 {+-} 0.24)% on (1.9893 {+-} 0.0060)cm{sup 2} (Fraunhofer ISE), i.e., areas large enough to be of

  4. Annual report of Department of Research Reactor and Tandem Accelerator, JFY2007. Operation, utilization and technical development of JRR-3, JRR-4, NSRR and tandem accelerator

    Miyazaki, Osamu; Awa, Yasuaki; Isaka, Koji; Kutsukake, Kenichi; Komeda, Masao; Shibata, Ko; Hiyama, Kazuhisa; Suzuki, Mayu; Sone, Takuya; Ohuchi, Tomoaki; Terakado, Yuichi; Sataka, Masao

    2009-06-01

    The Department of Research Reactors and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3(Japan Research Reactor-3), JRR-4(Japan Research Reactor-4), NSRR(Nuclear Safety Research Reactor) and Tandem Accelerator. This annual report describes a summary of activities of services and technical developments carried out in the period between April 1, 2007 and March 31, 2008. The activities were categorized into five service/development fields: (1) Operation and maintenance of research reactors and tandem accelerator. (2) Utilization of research reactors and tandem accelerator. (3) Upgrading of utilization techniques of research reactors and tandem accelerator. (4) Safety administration for research reactors and tandem accelerator. (5) International cooperation. Also contained are lists of publications, meetings, granted permissions on lows and regulations concerning atomic energy, commendation, plans and outcomes in service and technical developments and so on. (author)

  5. Annual report of Department of Research Reactor and Tandem Accelerator, JFY2010. Operation, utilization and technical development of JRR-3, JRR-4, NSRR and Tandem Accelerator

    Ishii, Tetsuro; Nakamura, Kiyoshi; Kawamata, Satoshi; Yamada, Yusuke; Kawashima, Kazuhiro; Asozu, Takuhiro; Nakamura, Takemi; Arai, Masaji; Yoshinari, Shuji; Sataka, Masao

    2012-03-01

    The Department of Research Reactors and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3(Japan Research Reactor No.3), JRR-4(Japan Research Reactor No.4), NSRR(Nuclear Safety Research Reactor) and Tandem Accelerator. This annual report describes a summary of activities of services and technical developments carried out in the period between April 1, 2010 and March 31, 2011. The activities were categorized into five service/development fields: (1) Operation and maintenance of research reactors and tandem accelerator, (2) Utilization of research reactors and tandem accelerator, (3) Upgrading of utilization techniques of research reactors and tandem accelerator, (4) Safety administration for research reactors and tandem accelerator, (5) International cooperation. Also contained are lists of publications, meetings, granted permissions on lows and regulations concerning atomic energy, commendation, outcomes in service and technical developments and so on. (author)

  6. Development of an advanced spacecraft tandem mass spectrometer

    Drew, Russell C.

    1992-03-01

    The purpose of this research was to apply current advanced technology in electronics and materials to the development of a miniaturized Tandem Mass Spectrometer that would have the potential for future development into a package suitable for spacecraft use. The mass spectrometer to be used as a basis for the tandem instrument would be a magnetic sector instrument, of Nier-Johnson configuration, as used on the Viking Mars Lander mission. This instrument configuration would then be matched with a suitable second stage MS to provide the benefits of tandem MS operation for rapid identification of unknown organic compounds. This tandem instrument is configured with a newly designed GC system to aid in separation of complex mixtures prior to MS analysis. A number of important results were achieved in the course of this project. Among them were the development of a miniaturized GC subsystem, with a unique desorber-injector, fully temperature feedback controlled oven with powered cooling for rapid reset to ambient conditions, a unique combination inlet system to the MS that provides for both membrane sampling and direct capillary column sample transfer, a compact and ruggedized alignment configuration for the MS, an improved ion source design for increased sensitivity, and a simple, rugged tandem MS configuration that is particularly adaptable to spacecraft use because of its low power and low vacuum pumping requirements. The potential applications of this research include use in manned spacecraft like the space station as a real-time detection and warning device for the presence of potentially harmful trace contaminants of the spacecraft atmosphere, use as an analytical device for evaluating samples collected on the Moon or a planetary surface, or even use in connection with monitoring potentially hazardous conditions that may exist in terrestrial locations such as launch pads, environmental test chambers or other sensitive areas. Commercial development of the technology

  7. Monolithic Parallel Tandem Organic Photovoltaic Cell with Transparent Carbon Nanotube Interlayer

    Tanaka, S.; Mielczarek, K.; Ovalle-Robles, R.; Wang, B.; Hsu, D.; Zakhidov, A. A.

    2009-01-01

    We demonstrate an organic photovoltaic cell with a monolithic tandem structure in parallel connection. Transparent multiwalled carbon nanotube sheets are used as an interlayer anode electrode for this parallel tandem. The characteristics of front and back cells are measured independently. The short circuit current density of the parallel tandem cell is larger than the currents of each individual cell. The wavelength dependence of photocurrent for the parallel tandem cell shows the superposition spectrum of the two spectral sensitivities of the front and back cells. The monolithic three-electrode photovoltaic cell indeed operates as a parallel tandem with improved efficiency.

  8. On the startup and shutdown of a tandem mirror reactor

    Chang, F.R.; DeCanio, F.T.; Fisher, J.L.; Madden, P.A.

    1979-01-01

    The startup and shutdown of a fusion reactor must be performed in such a way that the plasma remains MHD stable. In a tandem mirror the stability depends on a sufficiently high pressure ratio between the plugs and the central cell, of the order of 100. Control of the neutral beam input to the plugs by means of active feedback has been investigated to achieve an acceptable pressure ratio throughout the entire startup/shutdown transient. An algorithm to control the beam input power has been developed. The control law was subsequently tested in a tandem mirror simulation code. This paper describes the basic models incorporated in the simulation, as well as the derivation of the control algorithm. The simulation results are presented and the practicality of implementing the algorithm is discussed. 4 refs

  9. Single P-N junction tandem photovoltaic device

    Walukiewicz, Wladyslaw [Kensington, CA; Ager, III, Joel W.; Yu, Kin Man [Lafayette, CA

    2011-10-18

    A single P-N junction solar cell is provided having two depletion regions for charge separation while allowing the electrons and holes to recombine such that the voltages associated with both depletion regions of the solar cell will add together. The single p-n junction solar cell includes an alloy of either InGaN or InAlN formed on one side of the P-N junction with Si formed on the other side in order to produce characteristics of a two junction (2J) tandem solar cell through only a single P-N junction. A single P-N junction solar cell having tandem solar cell characteristics will achieve power conversion efficiencies exceeding 30%.

  10. Tandem mirror and field-reversed mirror experiments

    Coensgen, F.H.; Simonen, T.C.; Turner, W.C.

    1979-08-21

    This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.

  11. Magnet system for a thermal barrier Tandem Mirror Reactor

    Kim, N.S.; Conn, R.W.

    1981-01-01

    The magnet system for a thermal barrier D-D tandem mirror reactor has been studied as part of the UCLA tandem mirror reactor design study SATYR. Three main considerations in designing the SATYR magnet system are to obtain the desired field strength variation throughout the system, to have proper space for plasma and neutron shielding, and to satisfy the MHD stability to achieve maximum central cell /beta/. Due to the importance and the complexity, the 'internal' field reversal magnet is the main concern in the entire magnet system for SATYR. Two different magnet designs, a non-uniform current density solenoid and a higher-order solenoid, are discussed. Coil levitation for the internal field reversal magnet has been analyzed

  12. Graphene based integrated tandem supercapacitors fabricated directly on separators

    Chen, Wei

    2015-04-09

    It is of great importance to fabricate integrated supercapacitors with extended operation voltages as high energy density storage devices. In this work, we develop a novel direct electrode deposition on separator (DEDS) process to fabricate graphene based integrated tandem supercapacitors for the first time. The DEDS process generates compact graphene-polyaniline electrodes directly on the separators to form integrated supercapacitors. The integrated graphene-polyaniline tandem supercapacitors demonstrate ultrahigh volumetric energy density of 52.5 Wh L^(−1) at power density of 6037 W L^(−1) and excellent gravimetric energy density of 26.1 Wh kg^(−1) at power density of 3002 W kg^(−1) with outstanding electrochemical stability for over 10000 cycles. This study show great promises for the future development of integrated energy storage devices.

  13. Major maintenance of the Munich MP-tandem

    Muenzer, H.; Carli, W.; Hartung, P.; Jakob, H.; Nocker, H.; Rohrer, L.; Schnitter, H.; Assmann, W.; Maier, H.J.; Machlitt, N.; Steffens, H.

    1988-01-01

    Several measures have been taken to restore the voltage performance of the Munich tandem. 1. All accelerator tubes were reconditioned by sandblasting, new electrodes and diaphragms were inserted and preassembled groups of tubes were baked in high vacuum. 2. All other vacuum components were cleaned, baked in high vacuum and partly pressure leak tested outside the tandem. 3. High voltage tests were performed with tubes. Without portico voltages up to 16 MV were obtained, with portico up to 17.5 MV. 4. Some modifications (e.g. infrared light links) were introduced. The shutdown lasted 6 months. In March 1987 beam operation was resumed at moderate terminal voltages, interrupted by intervals of soft conditioning. (orig.)

  14. Use of molecular ion beams from a tandem accelerator

    Faibis, A.; Goldring, G.; Hass, M.; Kaim, R.; Plesser, I.; Vager, Z.

    1981-01-01

    A large variety of positive molecular ion beams can be produced by gaseous charge exchange in the terminal of a tandem accelerator. After acceleration the molecules are usually dissociated by passage through a thin foil. Measurements of the break-up products provide a way to study both the structure of incident ions and the effects of electronic potentials on the internuclear interaction inside the foil. Beam intensities of a few picoamperes are quite adequate for these measurements, and the relatively high energy obtained by use of a tandem accelerator has the advantage of minimizing multiple scattering effects in the foil. The main difficulty in using the molecular beams lies in the large magnetic rigidity of singly-charged heavy molecular ions

  15. Radiocarbon dating with the Chalk River MP Tandem accelerator

    Ball, G.C.; Andrews, H.R.; Brown, R.M.; Burn, N.; Davies, W.G.; Imahori, Y.; Milton, J.C.D.

    1981-01-01

    During the past three years an automated radiocarbon dating system based on the MP Tandem accelerator has been developed for the analysis of 14 C in groundwater samples from the nuclear waste disposal research program and other small samples of scientific interest. At the present time 14 C/ 12 C ratio measurements can be determined with an accuracy of about 5% and the system background levels (approx. 35000 to 45000 years) are totally determined by sample and/or ion source contamination. Our goal has been to develop a dedicated reliable system for routine analysis that will produce accurate results with a minimum expenditure of human resources and accelerator beam time. Improvements required to operate the tandem accelerator as a quantitative tool have also benefited the rest of the experimental nuclear physics program. The early evolution of the dating facility was described previously. This paper is a brief report of the current status at Chalk River

  16. Rhodium-Biphephos-Catalyzed Tandem Isomerization–Hydroformylation of Oleonitrile

    Lucas Le Goanvic

    2018-01-01

    Full Text Available Tandem isomerization–hydroformylation of oleonitrile (an 18-carbon nitrile with a remote internal (9-C=C bond has been studied using Rh-bisphosphite catalyst systems, targeting formation of the linear aldehyde. The best compromise between regioselectivity (l/b = 58:42 and chemoselectivity (60% was obtained at 120 °C and 10 bar CO/H2 (1:1 with a catalyst based on Biphephos at a 0.5 mol % catalyst load and a low ligand excess (2 equiv. versus Rh. These values stand among the better reported ones for the tandem isomerization–hydroformylation of long chain olefins with a single-component catalyst system.

  17. Accelerator tube vacuum conditions in the NSF tandem

    Groome, A.E.

    1979-08-01

    The Nuclear Structure Facility currently under construction at the Daresbury Laboratory contains a 30 MV tandem Van de Graaff accelerator with a modular design of accelerator tube. The vacuum system requirements are specified to limit beam loss due to charge-state-changing collisions in the residual gas. This report gives an assessment of some of the parameters affecting the vacuum pressure in an operational machine. Measurements are made of the vacuum conductance and outgassing rate of accelerator tube modules. An assessment is made of the effects of temperature rise, beam mis-steering and the presence of suppression magnets on the ultimate vacuum obtainable. Predictions are made of the pressure profile throughout the machine and consideration is given to operational problems such as tube conditioning and temporary loss of pumping. A schematic diagram of the tandem and its vacuum system is shown. (author)

  18. Summary of results from the Tandem Mirror Experiment (TMX)

    Simonen, T.C.

    1981-01-01

    This report summarizes results from the successful experimental operation of the Tandem Mirror Experiment (TMX) over the period October 1978 through September 1980. The experimental program, summarized by the DOE milestones given in Table 1-1, had three basic phases: (1) an 8-month checkout period, October 1978 through May 1979; (2) a 6-month initial period of operation, June through November 1979, during which the basic principles of the tandem configuration were demonstrated (i.e., plasma confinement was improved over that of a single-cell mirror); and (3) a 10-month period, December 1979 through September 1980, during which the initial TMX results were corroborated by additional diagnostic measurements and many detailed physics investigations were carried out. This report summarizes the early results, presents results of recent data analysis, and outlines areas of ongoing research and data analysis which will be reported in future journal publications

  19. MINIMARS: An attractive small tandem mirror fusion reactor

    Perkins, L.J.; Logan, B.G.; Doggett, J.N.; Devoto, R.S.

    1986-01-01

    Through the innovative design of a novel end plug scheme employing octopole MHD stabilization, the authors present the conceptual design of ''MINIMARS'', a small commercial fusion reactor based on the tandem mirror principle. The current baseline for MINIMARS has a net electric output of 600 MWe and they have configured the design for short construction times, factory-built modules, inherently safe blanket systems, and multiplexing in station sizes of ≅ 600-2400 MWe. They demonstrate that the compact octopole end cell provides a number of advantages over the more conventional quadrupole (yin-yang) end cell encountered in the MARS tandem mirror reactor study, and enables ignition to be achieved with much shorter central cell lengths. Accordingly, being economic in small sizes, MINIMARS provides an attractive alternative to the more conventional larger conceptual fusion reactors encountered to date, and would contribute significantly to the lowering of utility financial risk in a developing fusion economy

  20. The TESS [Tandem Experiment Simulation Studies] computer code user's manual

    Procassini, R.J.

    1990-01-01

    TESS (Tandem Experiment Simulation Studies) is a one-dimensional, bounded particle-in-cell (PIC) simulation code designed to investigate the confinement and transport of plasma in a magnetic mirror device, including tandem mirror configurations. Mirror plasmas may be modeled in a system which includes an applied magnetic field and/or a self-consistent or applied electrostatic potential. The PIC code TESS is similar to the PIC code DIPSI (Direct Implicit Plasma Surface Interactions) which is designed to study plasma transport to and interaction with a solid surface. The codes TESS and DIPSI are direct descendants of the PIC code ES1 that was created by A. B. Langdon. This document provides the user with a brief description of the methods used in the code and a tutorial on the use of the code. 10 refs., 2 tabs

  1. Interpretation of Tandem Mass Spectrometry (MSMS) Spectra for Peptide Analysis

    Hjernø, Karin; Højrup, Peter

    2015-01-01

    The aim of this chapter is to give a short introduction to peptide analysis by mass spectrometry (MS) and interpretation of fragment mass spectra. Through examples and guidelines we demonstrate how to understand and validate search results and how to perform de novo sequencing based on the often...... very complex fragmentation pattern obtained by tandem mass spectrometry (also referred to as MSMS). The focus is on simple rules for interpretation of MSMS spectra of tryptic as well as non-tryptic peptides....

  2. The Friction of Vehicle Brake Tandem Master Cylinder

    Kao, M J; Chang, H; Tsung, T T; Lin, H M

    2006-01-01

    The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications

  3. Accelerator mass spectrometry at the Rossendorf 5 MV tandem accelerator

    Friedrich, M.; Buerger, W.; Curian, H.; Hartmann, B.; Hentschel, E.; Matthes, H.; Probst, W.; Seidel, M.; Turuc, S.; Hebert, D.; Rothe, T.; Stolz, W.

    1992-01-01

    The Rossendorf electrostatic accelerators (5 MV tandem accelerator and single ended 2 MV van de Graaff accelerator) are already used for ion beam analysis. The existing methods (RBS, PIXE, ERDA, NRA, nuclear microprobe and external beam) will be completed by introduction of Accelerator Mass Spectrometry (AMS). A short description of the Rossendorf AMS system is given and first experimental results are presented. (R.P.) 4 refs.; 6 figs

  4. Neutral beam control systems for the Tandem Mirror Experiment

    Ross, R.I.

    1979-01-01

    The Tandem Mirror Experiment (TMX) is presently developing the technology and approaches which will be used in larger fusion systems. This paper describes some of the designs which were used in creating the control system for the TMX neutral beams. To create a system of controls that would work near these large, rapid switching current sources required a mixture of different technologies: fiberoptic data transmission, printed circuit and wirewrap techniques, etc

  5. Charge exchange cooling in the tandem mirror plasma confinement apparatus

    Logan, B. Grant

    1978-01-01

    Method and apparatus for cooling a plasma of warm charged species confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell, the cooling due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma.

  6. Charge exchange cooling in the tandem mirror plasma confinement apparatus

    Logan, B.G.

    1978-01-01

    A method and apparatus are described for cooling a plasma confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell. The cooling is due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma

  7. Tandem planet formation for solar system-like planetary systems

    Yusuke Imaeda

    2017-03-01

    Full Text Available We present a new united theory of planet formation, which includes magneto-rotational instability (MRI and porous aggregation of solid particles in a consistent way. We show that the “tandem planet formation” regime is likely to result in solar system-like planetary systems. In the tandem planet formation regime, planetesimals form at two distinct sites: the outer and inner edges of the MRI suppressed region. The former is likely to be the source of the outer gas giants, and the latter is the source for the inner volatile-free rocky planets. Our study spans disks with a various range of accretion rates, and we find that tandem planet formation can occur for M˙=10−7.3-10−6.9M⊙yr−1. The rocky planets form between 0.4–2 AU, while the icy planets form between 6–30 AU; no planets form in 2–6 AU region for any accretion rate. This is consistent with the gap in the solid component distribution in the solar system, which has only a relatively small Mars and a very small amount of material in the main asteroid belt from 2–6 AU. The tandem regime is consistent with the idea that the Earth was initially formed as a completely volatile-free planet. Water and other volatile elements came later through the accretion of icy material by occasional inward scattering from the outer regions. Reactions between reductive minerals, such as schreibersite (Fe3P, and water are essential to supply energy and nutrients for primitive life on Earth.

  8. Solution processed organic bulk heterojunction tandem solar cells

    Albrecht, Steve; Neher, Dieter [Soft Matter Physics, University of Potsdam, D-14476 Potsdam (Germany)

    2011-07-01

    One of the critical issues regarding the preparation of organic tandem solar cells from solution is the central recombination contact. This contact should be highly transparent and conductive to provide high recombination currents. Moreover it should protect the 1st subcell from the solution processing of the 2nd subcell. Here, we present a systematic study of various recombination contacts in organic bulk heterojunction tandem solar cells made from blends of different polymers with PCBM. We compare solution processed recombination contacts fabricated from metal-oxides (TiO{sub 2} and ZnO) and PEDOT:PSS with evaporated recombination contacts made from thin metal layers and molybdenum-oxide. The solar cell characteristics as well as the morphology of the contacts measured by AFM and SEM are illustrated. To compare the electrical properties of the varying contacts we show measurements on single carrier devices for different contact-structures. Alongside we present the results of optical modeling of the subcells and the complete tandem device and relate these results to experimental absorption and reflection spectra of the same structures. Based on these studies, layer thicknesses were adjusted for optimum current matching and device performance.

  9. Preliminary design of a Tandem-Mirror-Next-Step facility

    Damm, C.C.; Doggett, J.N.; Bulmer, R.H.

    1980-01-01

    The Tandem-Mirror-Next-Step (TMNS) facility is designed to demonstrate the engineering feasibility of a tandem-mirror reactor. The facility is based on a deuterium-tritium (D-T) burning, tandem-mirror device with a fusion power output of 245 MW. The fusion power density in the central cell is 2.1 MW/m 3 , with a resultant neutron wall loading of 0.5 MW/m 2 . Overall machine length is 116 m, and the effective central-cell length is 50.9 m. The magnet system includes end cells with yin-yang magnets to provide magnetohydrodynamic (MHD) stability and thermal-barrier cells to help achieve a plasma Q of 4.7 (where Q = fusion power/injected power). Neutral beams at energies up to 200 keV are used for plasma heating, fueling, and barrier pumping. Electron cyclotron resonant heating at 50 and 100 GHz is used to control the electron temperature in the barriers. Based on the resulting engineering design, the overall cost of the facility is estimated to be just under $1 billion. Unresolved physics issues include central-cell β-limits against MHD ballooning modes (the assumed reference value of β exceeds the current theory-derived limit), and the removal of thermalized α-particles from the plasma

  10. Photonic intermediate layer for silicon tandem solar cells

    Bielawny, Andreas; Miclea, Paul-Tiberiu; Wehrspohn, Ralf [Martin-Luther Universitaet Halle-Wittenberg (Germany). Inst. fuer Physik, Mikro-MD; Lee, Seuong-Mo; Knez, Mato [Max-Planck-Inst. fuer Mikrostrukturphysik, Halle (Germany); Carius, Reinhard [Forschungszentrum Juelich (DE). Inst. fuer Photovoltaik (IEF-5); Lisca, Marian; Rockstuhl, Carsten; Lederer, Falk [Universitaet Jena (Germany). Dept. Physik

    2008-07-01

    The concept of incorporation of a 3D photonic crystal as diffractive spectral filter within a-Si/mc-Si tandem solar cells has been investigated as a promising application. Our intermediate reflective filter enhances the pathway of spectrally selected light within an amorphous silicon top cell in its spectral region of low absorption. From our previous work, we expect a significant improvement of the tandem's efficiency of about 1.2%(absolute). This increases efficiency for a typical silicon tandem cell from 11.2% to 12.4%, as a result of the optical current-matching of the two junctions. Our wavelength-selective optical element is a 3D-structured optical thin-film - prepared by self-organized artificial opal templates and finalized with atomic layer deposition techniques. The resulting samples are highly periodical thin-film inverted opals made of zinc-oxide. We compare recent experimental data on the optical properties with our simulations and photonic bandstructure calculations.

  11. Evolution of the Fusion Power Demonstration tandem mirror reactor configuration

    O'Toole, J.A.; Lousteau, D.C.

    1985-01-01

    This paper gives a presentation of the evolution of configurations proposed for tandem mirror Fusion Power Demonstration (FPD) machines. The FPD study was undertaken to scope the mission as well as the technical and design requirements of the next tandem mirror device. Three configurations, entitled FPD I, II, and III were studied. During this process new systems were conceived and integrated into the design, resulting in a significantly changed overall machine configuration. The machine can be divided into two areas. A new center cell configuration, minimizing magnetic field ripple and thus maximizing center cell fusion power, features a semicontinuous solenoid. A new end cell has evolved which maintains the required thermal barrier in a significantly reduced axial length. The reduced end cell effective length leads to a shorter central cell length being required to obtain minimum ignition conditions. Introduced is the concept of an electron mantle stabilized octopole arrangement. The engineering features of the new end cell and maintenance concepts developed are influenced to a great extent by the octopole-based design. The new ideas introduced during the FPD study have brought forth a new perspective of the size, design, and maintenance of tandem mirror reactors, making them more attractive as commercial power sources

  12. Oak Ridge 25URC tandem accelerator 1994 SNEAP lab report

    Alton, G.D.; Dinehart, M.R.; Dowling, D.T.

    1994-01-01

    The 25URC tandem accelerator is still in shut-down mode until the facility is reconfigured to produce radioactive ion beams (RIBs). Again, the authors have operated approximately 200 hours for ion implantation studies in support of RIB development. Operation of the accelerator has been generally very reliable with most problems being associated with power supplies and components located outside the accelerator. The major operational problem this year was the development of internal shorts in the coils of the energy-analyzing magnet which caused beam instability. The major development activity for the tandem accelerator was the replacement of the corona-point voltage-grading system with resistors. Several milestones for the RIB project have been met since SNEAP 1993. The high-voltage platforms have been built and tested at the required 300 kV. Most equipment has been installed on the platforms so that the first beam can be developed using the Mark I target-ion source. This ion source was characterized on the ion source test facility before moving it to the platform. The second-stage mass-separator magnets have been specified and the contract has been awarded to Sigma Phi. The final optics design for the beam line from the second-stage separator to the tandem accelerator is being completed and equipment and controls are being procured

  13. Tandem collimators for the JET tangential gamma-ray spectrometer

    Soare, Sorin; Balshaw, Nick; Blanchard, Patrick; Craciunescu, Teddy; Croft, David; Curuia, Marian; Edlington, Trevor; Kiptily, Vasily; Murari, Andrea; Prior, Phil; Sanders, Steven; Syme, Brian; Zoita, Vasile

    2011-01-01

    The tangential gamma-ray spectrometer (TGRS) of the JET tokamak fusion facility is an important diagnostics for investigating the fast particle evolution. A well defined field of view for the TGRS diagnostics is essential for its proper operation and this is to be determined by a rather complex system of collimators and shields both for the neutron and gamma radiations. A conceptual design for this system has been carried out with the main design target set to maximize the signal-to-background ratio at the spectrometer detector, the ratio being defined in terms of the plasma emitted gamma radiation and the gamma-ray background. As a first phase of the TGRS diagnostics upgrade a set of two tandem collimators has been designed with the aim of determining a quasi-tangential field of view through JET tokamak plasmas. A modular design of the tandem system has been developed in order to allow for the construction of different configurations for deuterium and deuterium-tritium discharges. The internal structure of the collimators consists of nuclear grade lead and high density polyethylene slabs arranged in an optimized pattern. The performance of a simplified geometry of the tandem collimator configuration has been evaluated by neutron and photon transport calculations and the numerical results show that the design parameters can be attained.

  14. Annotating and Interpreting Linear and Cyclic Peptide Tandem Mass Spectra.

    Niedermeyer, Timo Horst Johannes

    2016-01-01

    Nonribosomal peptides often possess pronounced bioactivity, and thus, they are often interesting hit compounds in natural product-based drug discovery programs. Their mass spectrometric characterization is difficult due to the predominant occurrence of non-proteinogenic monomers and, especially in the case of cyclic peptides, the complex fragmentation patterns observed. This makes nonribosomal peptide tandem mass spectra annotation challenging and time-consuming. To meet this challenge, software tools for this task have been developed. In this chapter, the workflow for using the software mMass for the annotation of experimentally obtained peptide tandem mass spectra is described. mMass is freely available (http://www.mmass.org), open-source, and the most advanced and user-friendly software tool for this purpose. The software enables the analyst to concisely annotate and interpret tandem mass spectra of linear and cyclic peptides. Thus, it is highly useful for accelerating the structure confirmation and elucidation of cyclic as well as linear peptides and depsipeptides.

  15. Polarized ionic source of the tandem accelerator in Kyoto University

    Nakamura, Masanobu; Kuwamoto, Shuichi; Takahashi, Seiji [Kyoto Univ. (Japan). Dept. of Physics] [and others

    1997-02-01

    A polarized ion source developed under the National Laboratory of High Energy Physics was transferred to the tandem accelerator in Kyoto University at beginning of 1993 to constitute a displacement of incidence into the accelerator. This was an atomic beam type polarized ion source, which is designed to adopt permanent magnets for 6 poles magnet to polarize the electron, to take out atomic nucleus on a shape of positive ion by ECR ionizer after transferring its polarization through transition using radio frequency (RFT), to make it negative ion by charge conversion using alkaline metal vapor, and to put it into the tandem accelerator. Test of the positive ion was finished at the National Laboratory of High Energy Physics, and test in Kyoto University was required after its negative ionization. As the estimated cost was unsufficient and entrance into the ion source facility in the tandem accelerator building was limited in Kyoto University, step of development was slow. Here is reported on present state of the ion source which is now operating stably. (G.K.)

  16. Generating hydrogen from sunlight and water using photovoltaic tandem cell

    NONE

    2006-07-15

    Photoelectrochemical conversion of solar energy to energy in hydrogen at viable efficiency is a long-term goal needed to usher in the hydrogen economy worldwide. The twin cell technology based Tandem Cell tackles a number of challenges faced by single photoelectrochemical cell based water splitting and offers a novel way of utilising complimentary parts of the solar spectrum in two cells. The overall process results in a complete system driven by solar energy that splits water into hydrogen and oxygen. Hydrogen Solar Ltd is a UK based enterprise that is working towards commercialisation of this Tandem Cell technology. One of the main project activities involved the development and optimisation of methods for preparation of larger scale photocatalytic electrodes using reproducible low cost industrial processes, with efficiencies equal to or greater than those from small scale samples made experimentally in University laboratories. Stability is also an important issue and endurance testing was performed on some samples. Spray pyrolysis methods offer considerable promise as for preparation of metal oxide semiconductor films at low cost, reproducibly. These studies lead to optimised designs for Tandem Cells, resulting in construction of an array of 12 Tandem Cells. The findings of this array work, in particular engineering issues, were very significant. Based on this work it is intended to build another two array systems that consists of 24 Tandem Cells which will be tested for light to chemical conversion efficiency, to determine what efficiency has been achieved overall. The main conclusions resulting from this project were as follows. Overall, considerable progress was made in characterising the factors that affect photoelectrode performance efficiency but that, losses in efficiency when increasing the area of photoelectrodes was greater than expected and optimisation of efficiency at practical device scale needs more work. Based on the outcome of this work program

  17. Solution-processed parallel tandem polymer solar cells using silver nanowires as intermediate electrode.

    Guo, Fei; Kubis, Peter; Li, Ning; Przybilla, Thomas; Matt, Gebhard; Stubhan, Tobias; Ameri, Tayebeh; Butz, Benjamin; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2014-12-23

    Tandem architecture is the most relevant concept to overcome the efficiency limit of single-junction photovoltaic solar cells. Series-connected tandem polymer solar cells (PSCs) have advanced rapidly during the past decade. In contrast, the development of parallel-connected tandem cells is lagging far behind due to the big challenge in establishing an efficient interlayer with high transparency and high in-plane conductivity. Here, we report all-solution fabrication of parallel tandem PSCs using silver nanowires as intermediate charge collecting electrode. Through a rational interface design, a robust interlayer is established, enabling the efficient extraction and transport of electrons from subcells. The resulting parallel tandem cells exhibit high fill factors of ∼60% and enhanced current densities which are identical to the sum of the current densities of the subcells. These results suggest that solution-processed parallel tandem configuration provides an alternative avenue toward high performance photovoltaic devices.

  18. Classroom tandem – Outlining a model for language learning and ınstruction

    Katri Karjalaınen

    2013-11-01

    Full Text Available The aim of this paper is to outline classroom tandem by comparing it with informal tandem learning contexts and other language instruction methods. Classroom tandem is used for second language instruction in mixed language groups in the subjects of Finnish and Swedish as L2. Tandem learning entails that two persons with different mother tongues learn each other’s native languages in reciprocal cooperation. The students function, in turns, as a second language learner and as a model in the native language. We aim to give an overview description of the interaction in classroom tandem practice. The empirical data consists of longitudinal video recordings of meetings of one tandem dyad within a co-located Swedishmedium and Finnish-medium school. Focus in the analysis is on the language aspects the informants orient to and topicalize in their interaction. The language aspects vary depending on what classroom activities they are engaged in, text-based or oral activities.

  19. Tandem mirror reactor studies at Lawrence Livermore National Laboratory, FY 1980

    Carlson, G.A.; Neef, W.S. Jr.

    1981-03-20

    The principles of tandem mirror operation with thermal barriers will be demonstrated in the upgrade of the Tandem Mirror Experiment (TMX-U) in 1981 and the tandem configuration of the Mirror Fusion Test Facility (MFTF-B) in 1984. Continued analysis and conceptual design over this period will evolve the optimal configuration and parameters for a power-producing reactor. In this article we describe the progress we have made in this reactor design study effort during 1980.

  20. Tandem mirror reactor studies at Lawrence Livermore National Laboratory, FY 1980

    Carlson, G.A.; Neef, W.S. Jr.

    1981-01-01

    The principles of tandem mirror operation with thermal barriers will be demonstrated in the upgrade of the Tandem Mirror Experiment (TMX-U) in 1981 and the tandem configuration of the Mirror Fusion Test Facility (MFTF-B) in 1984. Continued analysis and conceptual design over this period will evolve the optimal configuration and parameters for a power-producing reactor. In this article we describe the progress we have made in this reactor design study effort during 1980

  1. On the Relativistic Correction of Particles Trajectory in Tandem Type Electrostatic Accelerator

    Minárik Stanislav

    2015-01-01

    A constant potential is applied to the acceleration of the ion-beam in the tandem type electrostatic accelerator. However, not just one voltage is applied, but instead a number of applications can be made in succession by means of the tandem arrangement of high voltage tubes. This number of voltage applications, which is the number of so-called "stages" of a tandem accelerator, may be two, three, or four, depending on the chosen design. Electrostatic field with approximately constant intensit...

  2. Establishment of a tandem ionization chamber system in standard mammography beams

    Silva, Jonas O. da; Caldas, L.V.E.

    2011-01-01

    A double-faced tandem ionization chamber system was developed at the Calibration Laboratory of IPEN. It has different collecting electrode materials: aluminium and graphite. The response repeatability and reproducibility and the energy dependence test of this tandem ionization chamber were evaluated. The chamber response stability is within the ±3% limit recommended in international standards. The energy dependence test of the ionization chamber system using the tandem curve obtained, presented agreement with literature results. (author)

  3. Status of the tandem FEL project development in Israel

    Benzvi, I.; Sokolowski, J.; Jerby, E.; Chomski, D.; Ruschin, S.

    1989-01-01

    The authors report the status of a collaborative research project development aimed toward construction of an IR FEL based on the EN tandem electrostatic accelerator of the Weizmann Institute of Science. A preliminary feasibility demonstration project yielded encouraging progress in three aspects: (1) Electron gun and accelerator conversion: A 50-kV 1-A electron gun injector was designed, built, tested, and assembled on the 6-MeV tandem accelerator which was previously converted and conditioned to operate as an electron accelerator in a positively charged HV terminal configuration. Contrary to the configuration of the only electrostatic accelerator FEL demonstrated so far, the electron gun and multistage depressed collector are connected to the ground, and the wiggler is placed in the HV terminal of the straight geometry tandem accelerator. This configuration promises to provide a high current high quality e-beam. (2) Electron-beam transport: The first installation of the electron optical beam recovery system yielded transport efficiency of 80%. Substantial improvement is expected with planned electron optics modifications. An effect, highly significant for realizing long pulse (quasi-cw) FEL operation, was observed experimentally. Due to the damping effect of the accelerator column capacitance network, the voltage terminal stayed constant for milliseconds even with poor beam transport efficiency. This points to the possibility of developing a long pulse FEL which may operate at a single longitudinal mode. (3) Wiggler development: A conventional 4.4-cm period SmCo planar wiggler was acquired and evaluated using a recently constructed floating wire magnetic field measurement setup

  4. Improved Tandem Measurement Techniques for Aerosol Particle Analysis

    Rawat, Vivek Kumar

    Non-spherical, chemically inhomogeneous (complex) nanoparticles are encountered in a number of natural and engineered environments, including combustion systems (which produces highly non-spherical aggregates), reactors used in gas-phase materials synthesis of doped or multicomponent materials, and in ambient air. These nanoparticles are often highly diverse in size, composition and shape, and hence require determination of property distribution functions for accurate characterization. This thesis focuses on development of tandem mobility-mass measurement techniques coupled with appropriate data inversion routines to facilitate measurement of two dimensional size-mass distribution functions while correcting for the non-idealities of the instruments. Chapter 1 provides the detailed background and motivation for the studies performed in this thesis. In chapter 2, the development of an inversion routine is described which is employed to determine two dimensional size-mass distribution functions from Differential Mobility Analyzer-Aerosol Particle Mass analyzer tandem measurements. Chapter 3 demonstrates the application of the two dimensional distribution function to compute cumulative mass distribution function and also evaluates the validity of this technique by comparing the calculated total mass concentrations to measured values for a variety of aerosols. In Chapter 4, this tandem measurement technique with the inversion routine is employed to analyze colloidal suspensions. Chapter 5 focuses on application of a transverse modulation ion mobility spectrometer coupled with a mass spectrometer to study the effect of vapor dopants on the mobility shifts of sub 2 nm peptide ion clusters. These mobility shifts are then compared to models based on vapor uptake theories. Finally, in Chapter 6, a conclusion of all the studies performed in this thesis is provided and future avenues of research are discussed.

  5. Effective Maxillary Protraction with Tandem Traction Bow Appliance

    Pravin Kumar S Marure

    2014-01-01

    Full Text Available Tandem traction bow appliance (TTBA promotes patient compliance, because it is more esthetic and comfortable than extraoral appliances. TTBA should be used only in case where maxillary deficiency and normal mandible is present. Advantages of it includes good oral hygiene, early treatment of any Class III malocclusion, optimal retention, distribution of the forces for protraction to all maxillary teeth, free mandibular movement. It can be used in conjunction with fixed appliances if necessary. This paper includes two case reports. The treatment results in both the cases demonstrated significant skeletal and dental response to TTBA therapy. Skeletal change was primarily a result of anterior movement of the maxilla.

  6. Parametric design study of tandem mirror fusion reactors

    Carlson, G.A.

    1977-01-01

    The parametric design study of the tandem mirror reactor (TMR) is described. The results of this study illustrate the variation of reactor characteristics with changes in the independent design parameters, reveal the set of design parameters which minimizes the cost of the reactor, and show the sensitivity of the optimized design to physics and technological uncertainties. The total direct capital cost of an optimized 1000 MWe TMR is estimated to be $1300/kWe. The direct capital cost of a 2000 MWe plant is less than $1000/kWe

  7. Instruction manual for ORNL tandem high abundance sensitivity mass spectrometer

    Smith, D.H.; McKown, H.S.; Chrisite, W.H.; Walker, R.L.; Carter, J.A.

    1976-06-01

    This manual describes the physical characteristics of the tandem mass spectrometer built by Oak Ridge National Laboratory for the International Atomic Energy Agency. Specific requirements met include ability to run small samples, high abundance sensitivity, good precision and accuracy, and adequate sample throughput. The instrument is capable of running uranium samples as small as 10 -12 g and has an abundance sensitivity in excess of 10 6 . Precision and accuracy are enhanced by a special sweep control circuit. Sample throughput is 6 to 12 samples per day. Operating instructions are also given

  8. A tandem cross-metathesis/semipinacol rearrangement reaction.

    Plummer, Christopher W; Soheili, Arash; Leighton, James L

    2012-05-18

    An efficient and (E)-selective synthesis of a 6-alkylidenebicyclo[3.2.1]octan-8-one has been developed. The key step is a tandem cross-metathesis/semipinacol rearrangement reaction, wherein the Hoveyda-Grubbs II catalyst, or more likely a derivative thereof, serves as the Lewis acid for the rearrangement. Despite the fact that both the starting alkene and the cross-metathesis product are viable rearrangement substrates, only the latter rearranges, suggesting that the Lewis acidic species is generated only after the cross-metathesis reaction is complete.

  9. Tailoring of targets for a tandem accelerator laboratory

    Sletten, G.

    1976-01-01

    The organization of a target laboratory serving the nuclear physics research at a tandem van de graaff accelerator is described. Emphasis is put on the layout of the laboratory and the mode of operation. The working force is about 40 h per week shared by two technical assistants, and they are supervised by a physicist who on the average spends about 1/3 of his time on target-related problems. Selected topics like heavy ion sputtering of actinides and the preparation of multilayer targets are described in detail. (author)

  10. Electrostatic field distributions in the Harwell Tandem accelerator

    Read, P.M.

    1981-11-01

    The electrostatic field distributions in the Harwell Tandem accelerator have been precisely calculated using the electrostatics program FINALE. The results indicate that the accelerator which presently has an upper voltage limit of 6.5 MV has the potential to operate at 8 MV. Such an upgrade could be achieved by a modification to the high voltage terminal. Replacement of the existing accelerator tubes with accelerator tubes capable of a gradient of 1.8 MV/m would also be required. The existing stack may also require replacement. The terminal modification itself would reduce the terminal to tank breakdown frequency. (author)

  11. Tandem mass spectrometry data quality assessment by self-convolution

    Tham Wai

    2007-09-01

    Full Text Available Abstract Background Many algorithms have been developed for deciphering the tandem mass spectrometry (MS data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on de novo sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified. Results The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores. Conclusion We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the

  12. Tandem mass spectrometry data quality assessment by self-convolution.

    Choo, Keng Wah; Tham, Wai Mun

    2007-09-20

    Many algorithms have been developed for deciphering the tandem mass spectrometry (MS) data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on de novo sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified. The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current) component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores. We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the predicted results. We conclude that the algorithm performs well

  13. Distributed control system for NSC tandem-LINAC

    Ajith Kumar, B.P.; Subrahmaniam, E.T.; Singh, Kundan

    2001-01-01

    The new control system for the tandem-LINAC accelerator system at Nuclear Science Centre (NSC), runs on a network of Pentiums under the LINUX operating system. Some of the computers are interfaced to the devices of the accelerator, using CAMAC, and run a server program. On the same network there are machines providing the operator interface, by running the client program. The client computers use the x-window graphics and shaft encoder knobs interfaced to them to provide the operator interface. The system supports the monitoring and controlling of all the accelerator parameters including the beam profile monitors, from any of the clients. (author)

  14. Present status of tandem accelerator in Tsukuba University

    Ishihara, Toyoyuki; Oshima, Hiroyuki; Ishii, Satoshi [Tsukuba Univ., Ibaraki (Japan). Tandem Accelerator Center; and others

    1996-12-01

    The tandem accelerator in Tsukuba University, 12UD Peletron, has continued the operation for 21 years, and the total operation time became 61,822 hours as of the end of March, 1996. In this paper, the state of operation of the tandem accelerator in 1995 and the state of use classified by experimental fields are reported. As for the improvement of peripheral equipment, the renewal of the radiation monitoring system and the new installation of the going-in and out control system for radiation control zones were carried out. In fiscal year 1995, the operation time of the accelerator was 3,966 hours, and ion acceleration time was 3,427 hours or 86%. The renewal and improvement of the accelerator system that had been begun in fiscal year 1989 was completed. Also the operation at highest accelerating voltage 12 MV was carried out for 7 hours. In March, the operation was not done because of the periodic inspection. The state of use of two ion sources for joint utilization is shown, and 20 kinds of ions were used. The state of joint utilization, the troubles and repair, and the renewal and new installation are reported. The plan of installing 1 MV TANDETRON is explained. (K.I.)

  15. {sup 36}Cl exposure dating with a 3-MV tandem

    Steier, Peter, E-mail: peter.steier@univie.ac.a [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Forstner, Oliver; Golser, Robin; Kutschera, Walter; Martschini, Martin [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Merchel, Silke [CEREGE, CNRS-IRD-Universite Aix-Marseille, Europole Mediterraneen de L' Arbois, 13545 Aix-en-Provence (France); Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Orlowski, Tobias; Priller, Alfred [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Vockenhuber, Christof [Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Wallner, Anton [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland)

    2010-04-15

    {sup 36}Cl AMS measurements at natural isotopic concentrations have yet been performed only at tandem accelerators with 5 MV terminal voltage or beyond. We have developed a method to detect {sup 36}Cl at natural terrestrial isotopic concentrations with a 3-MV system, operated above specifications at 3.5 MV. An effective separation was obtained with an optimized split-anode ionization chamber design (adopted from the ETH/PSI Zurich AMS group), providing a suppression factor of up to 30,000 for the interfering isobar {sup 36}S. Despite the good separation, a relatively high sulfur output from the ion source ({sup 36}S{sup -}/{sup 35}Cl{sup -} approx 4 x 10{sup -10} for samples prepared from chemically pure reagents), and a possibly cross contamination resulted in a background corresponding to {sup 36}Cl/Cl approx 3 x 10{sup -14}. The method was applied to samples containing between 10{sup 5} and 10{sup 6} atoms {sup 36}Cl/g rock from sites in Italy and Iran, which were already investigated by other laboratories for surface exposure dating. The {sup 36}Cl/Cl ratios in the range from 2 x 10{sup -13} to 5 x 10{sup -12} show a generally good agreement with the previous results. These first measurements demonstrate that also 3-MV tandems, constituting the majority of dedicated AMS facilities, are capable of {sup 36}Cl exposure dating, which is presently the domain of larger facilities.

  16. A Tandem-electrostatic-quadrupole for accelerator-based BNCT

    Kreiner, A.J.; Kwan, J.W.; Burlon, A.A.; Di Paolo, H.; Henestroza, E.; Minsky, D.M.; Valda, A.A.; Debray, M.E.; Somacal, H.

    2007-01-01

    A project to develop a Tandem-electrostatic-quadrupole (TESQ) accelerator for accelerator-based boron neutron capture therapy (AB-BNCT) is described. A folded Tandem, with 1.25 MV terminal voltage, combined with an electrostatic quadrupole (ESQ) chain is being proposed. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the 7 Li(p, n) 7 Be reaction slightly beyond its resonance at 2.25 MeV. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the 7 Li(p, n) 7 Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT

  17. Kyushu University Tandem Accelerator Laboratory report, 1988-1990

    Sagara, Kenshi; Morinobu, Shunpei

    1991-03-01

    Ten years have elapsed since the first beam was obtained from the Kyushu University tandem accelerator. Although the laboratory has achieved successful scientific results, the performance of the accelerator has been on a decline mainly due to the aging. In the last two and a half years, the tandem accelerator has suffered from the fall of terminal voltage to around 8 MV. However, the experimental studies in the laboratory have been active. The utilization of the polarized beams of protons and deuterons to study the scattering of the p+d system, the use of heavy ion beam for the systematic search for the molecular resonance in relatively heavy systems and for the study on reaction mechanism, the use of both light and heavy ion beams for the studies on nuclear engineering, material science and geological science and so on were carried out. The gamma ray spectroscopic study on the state near yrast line was largely hampered by the accelerator troubles, instead, the collaboration with the Niels Bohr Institute provided a wonderful research ground for the studies. (K.I.)

  18. Octopole and hexapole end cells for tandem mirrors

    Devoto, R.S.

    1985-01-01

    To date, nearly all operating or planned tandem mirror experiments use quadrupole magnetic fields in the end cells for stabilization of magnetohydrodynamic (MHD) instabilities. A disadvantage with quadrupole fields is the considerable aximuthal asymmetry in the magnetic field. As a result, those center-cell ions which pass into the end cell can suffer a radial deflection and be lost by radial diffusion. The diffusion can be minimized by adding C-coils to the end cell to symmetrize the geodesic curvature in the end cell. Very small radial deflection can be obtained on each field line. Such a method is used in the design of the MFTF-B experiment and the MARS reactor. A disadvantage of this approach is the large number of coils required. In addition, since ions drift azimuthally as they reflect in the end cell, even perfect cancellation on individual field lines will, in general, not lead to zero radial diffusion. One way to form a more symmetric field in the end cells is to use multipoles higher than quadrupole. The use of an octopole end cell for a small tandem-mirror reactor was recently proposed/sup L/ and has been adopted for the miniMARS reactor study. In this paper the author discusses some feature of octopole, and to a lesser extent, hexapole end cells in both reactor and experimental (MFTF-B) applications

  19. Beam emittance of the Stony Brook Tandem-LINAC booster

    Scholldorf, A.H.

    1984-01-01

    This dissertation is primarily a study of the longitudinal and transverse beam emittance of the Stony Brook Heavy Ion Tandem LINAC Accelerator Facility, with a secondary emphasis on the beam dynamical design of two key elements of the system: a low energy double-drift buncher, and an achromatic double-90 0 LINAC injection system. A transverse emittance measuring system consisting of two translation stages controlled by stepper motors is described. Each stage carried a pair of beam defining slits mounted so that both horizontal and vertical emittances could be measured with only linear motion of the stage assembly. Beam currents were measured directly by a low-noise, high-sensitivity electrometer circuit integrated with the second slit-stage assembly. A mini-computer controlled the motors and acquired and displayed the data. Transverse emittance areas of beams of 12 C, 16 O, 32 S, and 58 Ni were measured at ion source extraction potential, after ion source acceleration, after tandem acceleration, and after LINAC acceleration. The results were analyzed in terms of source sputter-cone geometry, angle straggling in gas and foil strippers, and a variety of other factors

  20. Tandem walking as a quick screening test for vestibular disorders.

    Cohen, Helen S; Stitz, Jasmine; Sangi-Haghpeykar, Haleh; Williams, Susan P; Mulavara, Ajitkumar P; Peters, Brian T; Bloomberg, Jacob J

    2017-12-11

    Although many screening tests of balance are available, few of them have been well validated for clinical or research uses. The goal of this study was to test an updated version of an old test, Tandem Walking, to determine how useful it is for screening patients with vestibular disorders. Case-control study. Subjects were 90 adult patients with vestibular disorders and 292 healthy adult controls. They were tested on the number of correct tandem steps they could perform with arms crossed and eyes closed in a series of 10 steps. Correct steps could be nonconsecutive. Subjects were given one practice trial with eyes open and three experimental trials with eyes closed. Receiver operating characteristic (ROC), and sensitivity and specificity were calculated. ROC values, sensitivity, and specificity were, at best, only moderate, no matter how the age range was cut. Even for subjects in the age group with the highest ROC value (i.e., age less than 50 years), ROC = 0.8, sensitivity = 0.77, and specificity = 0.72. These results indicate that 23% of patients will not be identified. Therefore, we recommend that if this test is used for screening patients in the clinic or healthy volunteers, the result should be interpreted with care. 3b Laryngoscope, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  1. Carbon nanotube foils for electron stripping in tandem accelerators

    Reden, Karl von; Zhang Mei; Meigs, Martha; Sichel, Enid; Fang Shaoli; Baughman, Ray H.

    2007-01-01

    Carbon nanotube technology has rapidly advanced in recent years, making it possible to create meter-long, ∼4 cm wide films of multi-walled tubes of less than 3 μg/cm 2 areal density in a bench top open-air procedure. The physical properties of individual carbon nanotubes have been well established, equaling or surpassing electrical and thermal conductivity and mechanical strength of most other materials, graphite in particular. The handling and transport of such nanotube films, dry-mounted self-supporting on metal frames with several cm 2 of open area, is problem-free: the aerogel films having a volumetric density of about 1.5 mg/cm 3 survived the trip by car and air from Dallas to Oak Ridge without blemish. In this paper we will present the results of first tests of these nanotube films as electron stripper media in a tandem accelerator. The tests were performed in the Model 25 URC tandem accelerator of the Holifield radioactive ion beam facility (HRIBF) at Oak Ridge National Laboratory. We will discuss the performance of nanotube films in comparison with chemical vapor deposition and laser-ablated carbon foils

  2. Use of TANDEM methodology for quality control in radiation protection

    Mello, O.A.; Oliveira, I.R.; Leyton, F.; Nogueira, M.S.; Borges, F.L.S.; Joana, G.S.

    2014-01-01

    Recent studies have indicated the increase of the incidence of lens opacities for low radiation doses. Considering epidemiological data, the International Commission on Radiological Protection (ICRP) issued a statement that changed the absorbed dose threshold for the eye lens. The statement also recommends a reduction in the dose limits to the eye lens for occupationally exposed persons; now it is considered to be 20 mSv in a year averaged over five years. For this research two types of thermoluminescent dosimeters TL were used in the construction of the curve tandem. (LiF-100H e LiF-200). For system calibration three monitors were irradiated for each radiation beam. The monitors were irradiated with 4 mGy kerma at 1.5 m from the focal point. The Tandem curve was obtained by the ratio between the values of the energy dependence curves of each dosimeter. Data obtained for the corresponding x-ray beams to radiation reference N60 to N120 are more accurate for determining the energy - steepest part of the curve. The results are shown similar to similar studies and confirm the possibility of using the method for determining the unknown energy radiation fields. (author)

  3. Vacuum system of tandem type electrostatic accelerator of Kyushu University

    Nakajima, Yutaka

    1981-01-01

    In the tandem type electrostatic accelerator of Kyushu University, the problem of vacuum in the beam transport system including the accelerator tube has been considered as one of the important elements for the performance of the electrostatic accelerator from the beginning of construction. Though the three-stage tandem accelerating scheme was considered as the beam transport system at the beginning of the program, in which the existing 6 MV Van de Graaf accelerator was to be used as the injector, three types of ion sources are prepared at present; the sputter ion source to generate negative heavy ions, the polarizing ion source to generate negative polarized protons or deuterons, and direct extraction type negative ion source. Ultrahigh evacuating system, in which the sputter ion pump is mainly employed, and the turbo-molecular pump is used supplementarily, was installed in the vacuum system. The vacuum of approximately 10 - 9 Torr level off-beam at the inlet or outlet of the accelerator tube and approximately 10 - 8 Torr level in the tubing section in the center terminal were achieved. Since the upper limit of withstand voltage of the accelerating tube was not able to be satisfied for the insufficient baking at the beginning, it was finally decided that the accelerating tube should be heated by directly supplying power to the electrode through low voltage discharge in the tube. This method enabled the generated voltage at the terminal to exceed 10 MV. (Wakatsuki, Y.)

  4. Annual report of the Tandem Accelerator Center, University of Tsukuba

    1985-01-01

    This annual report covers the work carried out at the Tandem Accelerator Center, University of Tsukuba, during fiscal year 1984. The 12 UD Pelletron tandem accelerator was operated very stably. In addition, the heavy ion post accelerator with interdigital-H structure has worked well, providing additional energy of 2 MeV per charge for heavy ions. The constructions of a new Lamb-shift polarized ion source, a multi-computer control system for the ion sources of the UTTA, an electrostatic inflection system of incident ions for the UTTA, a new beam bunching system, and a new SF 6 gas handling system were under way. The development and performance test of various radiation detector systems were carried out. Two thirds of the research works were performed by using the beam from the Lamb-shift polarized ion source (PIS). A newly constructed fast spin state interchange control system for the PIS made polarization experiment more effective and accurate. The research activities in the fields of nuclear physics, atomic and solid state physics, and biology and medical science are reported. (Kako, I.)

  5. Two tandemly repeated telomere-associated sequences in Nicotiana plumbaginifolia.

    Chen, C M; Wang, C T; Wang, C J; Ho, C H; Kao, Y Y; Chen, C C

    1997-12-01

    Two tandemly repeated telomere-associated sequences, NP3R and NP4R, have been isolated from Nicotiana plumbaginifolia. The length of a repeating unit for NP3R and NP4R is 165 and 180 nucleotides respectively. The abundance of NP3R, NP4R and telomeric repeats is, respectively, 8.4 x 10(4), 6 x 10(3) and 1.5 x 10(6) copies per haploid genome of N. plumbaginifolia. Fluorescence in situ hybridization revealed that NP3R is located at the ends and/or in interstitial regions of all 10 chromosomes and NP4R on the terminal regions of three chromosomes in the haploid genome of N. plumbaginifolia. Sequence homology search revealed that not only are NP3R and NP4R homologous to HRS60 and GRS, respectively, two tandem repeats isolated from N. tabacum, but that NP3R and NP4R are also related to each other, suggesting that they originated from a common ancestral sequence. The role of these repeated sequences in chromosome healing is discussed based on the observation that two to three copies of a telomere-similar sequence were present in each repeating unit of NP3R and NP4R.

  6. The First Tandem, All-exciplex-based WOLED

    Hung, Wen-Yi; Fang, Guan-Cheng; Lin, Shih-Wei; Cheng, Shuo-Hsien; Wong, Ken-Tsung; Kuo, Ting-Yi; Chou, Pi-Tai

    2014-06-01

    Exploiting our recently developed bilayer interface methodology, together with a new wide energy-gap, low LUMO acceptor (A) and the designated donor (D) layers, we succeeded in fabricating an exciplex-based organic light-emitting diode (OLED) systematically tuned from blue to red. Further optimization rendered a record-high blue exciplex OLED with ηext of 8%. We then constructed a device structure configured by two parallel blend layers of mCP/PO-T2T and DTAF/PO-T2T, generating blue and yellow exciplex emission, respectively. The resulting device demonstrates for the first time a tandem, all-exciplex-based white-light OLED (WOLED) with excellent efficiencies ηext: 11.6%, ηc: 27.7 cd A-1, and ηp: 15.8 ml W-1 with CIE(0.29, 0.35) and CRI 70.6 that are nearly independent of EL intensity. The tandem architecture and blend-layer D/A (1:1) configuration are two key elements that fully utilize the exciplex delay fluorescence, providing a paragon for the use of low-cost, abundant organic compounds en route to commercial WOLEDs.

  7. Plasma confinement in the GAMMA 10 tandem mirror

    Yatsu, K.; Bruskin, L.G.; Cho, T.

    1999-01-01

    The central-cell density and the diamagnetic signal were doubled due to plug potential formation by ECRH in the hot ion mode experiments on the GAMMA 10 tandem mirror. In order to obtain these remarkable results, the axisymmetrized heating patterns of ECRH and ICRF were optimized. Furthermore, conducting plates were installed adjacent to the surface of the plasma along the flat shaped magnetic flux tube located at the anchor transition regions; the plates may contribute to reduce some irregular electric fields produced possibly with ECRH in these thin flux tube regions. The conducting plates contributed to the reduction of the radial loss rate to be less than 3% of the total particle losses along with the improvements in the reproducibility of the experiments and the controllability of the potential confinement. The increases in the central-cell density and the diamagnetism in association with the increase in the plug potentials scaled well with increasing the ECRH powers. A plug potential of 0.6 kV and a density increase of 100% were achieved using an ECRH power of 140 kW injected into both plug regions. The plasma confinement was improved by an order of magnitude over a simple mirror confinement due to the tandem mirror potential formation. (author)

  8. Tandem-ESQ for accelerator-based BNCT

    Kreiner, A.J.; Burlon, A.A.; Di Paolo, H.; Minsky, D.M.; Valda, A.A.; Debray, M.E.; Somacal, H.R.; Kwan, J.W.; Henestroza, E.

    2006-01-01

    A project to develop a Tandem-ElectroStatic-Quadrupole (TESQ) accelerator for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT) is described. A folded tandem, with 1.25 MV terminal voltage, combined with an ElectroStatic Quadrupole (ESQ) chain is being proposed. The project goal is a machine capable of delivering 30 mA of 2.5 MeV protons to be used in conjunction with a neutron production target based on the 7 Li(p,n) 7 Be reaction beyond its resonance at 2.25 MeV. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the '7Li(p,n) 7 Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is the technologically simplest and cheapest solution for optimized AB-BNCT. (author)

  9. Hydrodynamic studies on two traveling wavy foils in tandem arrangement

    Deng, Jian; Shao, Xue-Ming; Yu, Zhao-Sheng

    2007-11-01

    In this study, the hydrodynamic interactions between two tandem foils undergoing fishlike swimming motion are investigated numerically by solving the Navier-Stokes equations with the immersed-boundary method. The two foils represent two tandem propellers attached on a concept ship. The thrusts and efficiencies at three typical Strouhal numbers, i.e., St =0.4, 0.6, and 0.8, are investigated. The results show that a fish situated directly behind another one does not always undergo a lower thrust. Whether it experiences a thrust enhancement or reduction depends on the Strouhal number. At a relatively low Strouhal number (e.g., St =0.4), the usual wake drag-reduction effect predominates over the drag-enhancement effect caused by the reverse von Kármán vortices, resulting in a thrust enhancement. The opposite happens at a relatively high Strouhal number (e.g., St =0.8). The downstream fish can benefit from the upstream one by slalom between the vortices rather than through them. For the upstream fish, the thrusts and efficiencies for all Strouhal numbers studied are higher than those for a single fish when the two fish are closely spaced, and approach those for a single fish as the spacing is increased.

  10. Development of high current injector for tandem accelerator

    Baba, Takashi; Iwamoto, Eiji [Nissin - High Voltage Co. Ltd., Kyoto (Japan); Kishimoto, Naoki; Saito, Tetsuya; Mori, Yoshiharu

    1997-02-01

    The development of the electrostatic type tandem accelerators has been carried out so far, but by the recent remarkable progress of negative ion sources, the beam current which was inconceivable so far has become obtainable, and the use as the electrostatic type tandem accelerators is expanding rapidly. The problem which must be solved in the development of a high energy, large current heavy ion injection device is the development of an injector. As to the generation of negative ions, by the development of plasma sputter negative ion sources, the almost satisfactory performance has been obtained in beam current, emittance, life and so on, but as for the transport and control of generated negative ion beam, there is the large problem of spatial charge effect. This time, the verifying test on this problem was carried out, therefore, its contents and results are reported. The equipment which was developed this time was delivered to the Institute for Materials Research. Its specifications are shown. The whole constitution, negative ion source, and beam transport system are described. Beam generation test and spatial charge effect test are reported. The test stand was made, and in the verifying test, the maximum beams of 4 mA in Cu and 3 mA in Ni were able to be generated and transported. The effect of the countermeasures to spatial charge effect was confirmed. (K.I.)

  11. Determination of 5-fluorouracil in plasma with HPLC-tandem mass spectrometry

    van Kuilenburg, A. B. P.; van Lenthe, H.; Maring, J. G.; van Gennip, A. H.

    2006-01-01

    In this article, we describe a fast and specific method to measure 5FU with HPLC tandem-mass spectrometry. Reversed-phase HPLC was combined with electrospray ionization tandem mass spectrometry and detection was performed by multiple-reaction monitoring. Stable-isotope-labeled 5FU (1,3-15N2-5FU) was

  12. Status of the Catania tandem as injector of the superconducting cyclotron

    Ciavola, G.; Cuttone, G.; Raia, G.

    1990-01-01

    The Catania LNS tandem facility is operating since 1984. The status and the main modifications of the accelerator during these years are described and the performance obtained is reported. A superconducting cyclotron will be installed at the LNS facility as tandem booster; the main progress is presented. (orig.)

  13. Catalytic stereoselective synthesis of highly substituted indanones via tandem Nazarov cyclization and electrophilic fluorination trapping.

    Nie, Jing; Zhu, Hong-Wei; Cui, Han-Feng; Hua, Ming-Qing; Ma, Jun-An

    2007-08-02

    A new catalytic stereoselective tandem transformation via Nazarov cyclization/electrophilic fluorination has been accomplished. This sequence is efficiently catalyzed by a Cu(II) complex to afford fluorine-containing 1-indanone derivatives with two new stereocenters with high diastereoselectivity (trans/cis up to 49/1). Three examples of catalytic enantioselective tandem transformation are presented.

  14. Solution-processed organic tandem solar cells with embedded optical spacers

    Hadipour, Afshin; de Boer, Bert; Blom, Paul W. M.

    2007-01-01

    We demonstrate a solution-processed polymer tandem solar cell in which the two photoactive single cells are separated by an optical spacer. The use of an optical spacer allows for an independent optimization of both the electronic and optical properties of the tandem cell. The optical transmission

  15. Analysis of genetic polymorphism of nine short tandem repeat loci in ...

    Yomi

    2012-03-15

    Mar 15, 2012 ... Key words: short tandem repeat, repeat motif, genetic polymorphism, Han population, forensic genetics. INTRODUCTION. Short tandem repeat (STR) is widely .... Data analysis. The exact test of Hardy-Weinberg equilibrium was conducted with. Arlequin version 3.5 software (Computational and Molecular.

  16. Simulation of Two Dimensional Electrophoresis and Tandem Mass Spectrometry for Teaching Proteomics

    Fisher, Amanda; Sekera, Emily; Payne, Jill; Craig, Paul

    2012-01-01

    In proteomics, complex mixtures of proteins are separated (usually by chromatography or electrophoresis) and identified by mass spectrometry. We have created 2DE Tandem MS, a computer program designed for use in the biochemistry, proteomics, or bioinformatics classroom. It contains two simulations--2D electrophoresis and tandem mass spectrometry.…

  17. Exploring dark current voltage characteristics of micromorph silicon tandem cells with computer simulations

    Sturiale, A.; Li, H. B. T.; Rath, J.K.; Schropp, R.E.I.; Rubinelli, F.A.

    2009-01-01

    The transport mechanisms controlling the forward dark current-voltage characteristic of the silicon micromorph tandem solar cell were investigated with numerical modeling techniques. The dark current-voltage characteristics of the micromorph tandem structure at forward voltages show three regions:

  18. Zinc tin oxide as high-temperature stable recombination layer for mesoscopic perovskite/silicon monolithic tandem solar cells

    Werner, Jé ré mie; Walter, Arnaud; Rucavado, Esteban; Moon, Soo Jin; Sacchetto, Davide; Rienaecker, Michael; Peibst, Robby; Brendel, Rolf; Niquille, Xavier; De Wolf, Stefaan; Lö per, Philipp; Morales-Masis, Monica; Nicolay, Sylvain; Niesen, Bjoern; Ballif, Christophe

    2016-01-01

    the concept, we fabricate monolithic tandem cells with mesoscopic top cell with up to 16% efficiency. We then investigate the effect of zinc tin oxide layer thickness variation, showing a strong influence on the optical interference pattern within the tandem

  19. Annual report of Department of Research Reactor and Tandem Accelerator, JFY2011. Operation, utilization and technical development of JRR-3, JRR-4, NSRR and tandem accelerator

    Ishii, Tetsuro; Nakamura, Kiyoshi; Kawamata, Satoshi; Ishikuro, Yasuhiro; Kawashima, Kazuhito; Kabumoto, Hiroshi; Nakamura, Takemi; Tamura, Itaru; Kawasaki, Sayuri; Sataka, Masao

    2013-03-01

    The Department of Research Reactors and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3(Japan Research Reactor No.3), JRR-4(Japan Research Reactor No.4), NSRR(Nuclear Safety Research Reactor) and Tandem Accelerator. This annual report describes a summary of activities of services and technical developments carried out in the period between April 1, 2011 and March 31, 2012. The activities were categorized into six service/development fields: (1) Recovery from the Great East Japan Earthquake, (2) Operation and maintenance of research reactors and tandem accelerator, (3) Utilization of research reactors and tandem accelerator, (4) Upgrading of utilization techniques of research reactors and tandem accelerator, (5) Safety administration for research reactors and tandem accelerator, (6) International cooperation. Also contained are lists of publications, meetings, granted permissions on lows and regulations concerning atomic energy, number of staff members dispatched to Fukushima for the technical assistance, commendation, outcomes in service and technical developments and so on. (author)

  20. Use of TANDEM methodology for quality control in radiation protection; Aplicacao de metodologia TANDEM para controle de qualidade em radioprotecao

    Mello, O.A.; Oliveira, I.R.; Leyton, F.; Nogueira, M.S., E-mail: mnogueira@cdtn.br [Centro de Desenvolvimeto da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Borges, F.L.S., E-mail: flavialuizaborges@yahoo.com.br [Vigilancia Sanitaria de Minas Gerais, Belo Horizonte, MG (Brazil); Joana, G.S., E-mail: georgia.joana@gmail.com [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil)

    2014-07-01

    Recent studies have indicated the increase of the incidence of lens opacities for low radiation doses. Considering epidemiological data, the International Commission on Radiological Protection (ICRP) issued a statement that changed the absorbed dose threshold for the eye lens. The statement also recommends a reduction in the dose limits to the eye lens for occupationally exposed persons; now it is considered to be 20 mSv in a year averaged over five years. For this research two types of thermoluminescent dosimeters TL were used in the construction of the curve tandem. (LiF-100H e LiF-200). For system calibration three monitors were irradiated for each radiation beam. The monitors were irradiated with 4 mGy kerma at 1.5 m from the focal point. The Tandem curve was obtained by the ratio between the values of the energy dependence curves of each dosimeter. Data obtained for the corresponding x-ray beams to radiation reference N60 to N120 are more accurate for determining the energy - steepest part of the curve. The results are shown similar to similar studies and confirm the possibility of using the method for determining the unknown energy radiation fields. (author)

  1. Mass spectrometry and tandem mass spectrometry of citrus limonoids.

    Tian, Qingguo; Schwartz, Steven J

    2003-10-15

    Methods for atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS) of citrus limonoid aglycones and electrospray ionization tandem mass spectrometry (ESI-MS/MS) of limonoid glucosides are reported. The fragmentation patterns of four citrus limonoid aglycones (limonin, nomilin, obacunone, and deacetylnomilin) and six limonoid glucosides, that is, limonin 17-beta-D-glucopyranoside (LG), nomilin 17-beta-D-glucopyranoside (NG), nomilinic acid 17-beta-D-glucopyranoside (NAG), deacetyl nomilinic acid 17-beta-D-glucopyranoside (DNAG), obacunone 17-beta-D-glucopyranoside (OG), and obacunoic acid 17-beta-D-glucopyranoside (OAG) were investigated using a quadruple mass spectrometer in low-energy collisionally activated dissociation (CAD). The four limonoid aglycones and four limonoid glucosides (LG, OG, NAG, and DNAG) were purified from citrus seeds; the other two limonoid glucosides (NG and OAG) were tentatively identified in the crude extract of grapefruit seeds by ESI mass spectrometry in both positive and negative ion analysis. Ammonium hydroxide or acetic acid was added to the mobile phase to facilitate ionization. During positive ion APCI analysis of limonoid aglycones, protonated molecular ion, [M + H]+, or adduct ion, [M + NH3 + H]-, was formed as base peaks when ammonium hydroxide was added to the mobile phase. Molecular anions or adduct ions with acetic acid ([M + HOAc - H] and [M + HOAc]-) or a deprotonated molecular ion were produced during negative ion APCI analysis of limonoid aglycones, depending on the mobile-phase modifier used. Positive ion ESI-MS of limonoid glucosides produced adduct ions of [M + H + NH3]+, [M + Na]+, and [M + K]+ when ammonium hydroxide was added to the mobile phase. After collisionally activated dissociation (CAD) of the limonoid aglycone molecular ions in negative ion APCI analysis, fragment ions indicated structural information of the precursor ions, showing the presence of methyl, carboxyl, and oxygenated ring

  2. 21 CFR 862.1055 - Newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

    2010-04-01

    ..., free carnitine, and acylcarnitines using tandem mass spectrometry. 862.1055 Section 862.1055 Food and... screening test system for amino acids, free carnitine, and acylcarnitines using tandem mass spectrometry. (a) Identification. A newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

  3. Physics-magnetics trade studies for tandem mirror reactors

    Campbell, R.B.; Perkins, L.J.; Blackfield, D.T.

    1985-01-01

    We describe and present results obtained from the optimization package of the Tandem Mirror Reactor Systems Code. We have found it to be very useful in searching through multidimensional parameter space, and have applied it here to study the effect of choke coil field strength and net electric power on cost of electricity (COE) and mass utilization factor (MUF) for MINIMARS type reactors. We have found that a broad optimum occurs at B/sub choke/ = 26 T for both COE and MUF. The COE economy of scale approaches saturation at quite low powers, around 600 MW(e). The saturation is mainly due to longer construction times for large plants, and the associated time related costs. The MUF economy of scale does not saturate, at least for powers up to 2400 MW(e)

  4. Gas box control system for Tandem Mirror Experiment-Upgrade

    Bell, H.H. Jr.; Hunt, A.L.; Clower, C.A. Jr.

    1983-01-01

    The Tandem Mirror Experiment-Upgrade (TMX-U) uses several methods to feed gas (usually deuterium) at different energies into the plasma region of the machine. One is an arrangement of eight high-speed piezo-electric valves mounted on special manifolds (gas box) that feed cold gas directly to the plasma. This paper describes the electronic valve control and data acquisition portions of the gas box, which are controlled by a desk-top computer. Various flow profiles have been developed and stored in the control computer for ready access by the operator. The system uses two modes of operation, one that exercises and characterizes the valves and one that operates the valves with the rest of the experiment. Both the valve control signals and the pressure transducers data are recorded on the diagnostics computer so that they are available for experiment analysis

  5. Configuration and layout of the tandem mirror Fusion Power Demonstrator

    Clarkson, I.R.; Neef, W.S.

    1983-01-01

    Studies have been performed during the past year to determine the configuration of a tandem mirror Fusion Power Demonstrator (FPD) machine capable of producing 1750 MW of fusion power. The FPD is seen as the next logical step after the Mirror Fusion Test Facility-B (MFTF-B) toward operation of a power reactor. The design of the FPD machine allows a phased construction: Phase I, a hydrogen or deuterium checkout machine; Phase 2, a DT breakeven machine; Phase 3, development of the Phase 2 machine to provide net power and act as a reactor demonstrator. These phases are essential to the development of remote handling equipment and the design of components that will ultimately be remotely handled. Phasing also permits more modes funding early in the program with some costs committed only after reaching major milestones

  6. The tandem Tritron control system, a status report

    Rohrer, L.; Schnitter, H.; Cazan, A.; Jakubowska, E.; Walchshaeusl, B.

    1994-01-01

    The control system for the tandem accelerator and the Tritron was put into operation in 1988 and has been developed further continuously. It consists of many Z280 microcomputer crates, equipped with I/O-boards to control accelerator devices, personal computers serving as control desks, a file server, an address server, and an error logger. All computers are interconnected by an ARCnet local area network. The program language in every computer and the communication language is FORTH. Every node contains a multitasking FORTH system with floating point arithmetic from the beginning and interprets or compiles the data stream coming from the ARCnet. Each node is programmed with its special program so that it can perform its specific control or monitor task. The system is very flexible. Every node may be changed or replaced by a better one, if necessary. The only condition is that it can be connected to the ARCnet and can be programmed in FORTH. ((orig.))

  7. Analysis and simulation of an electrostatic FN Tandem accelerator

    Ugarte, Ricardo

    2007-01-01

    An analysis, modeling, and simulation of a positive ion FN Tandem electrostatic accelerator has been done. That has induced a detailed study over all physics components inside the accelerators tank, the terminal control stabilizer (TPS), the corona point, the capacitor pick off (CPO) and over the generating voltmeter (GVM) signals. The parameter of the model has been developed using the Prediction Error estimation Methods (PEM), and within classical techniques of analysis of circuits. The result obtained was used to check and increase the stability of the terminal voltage using Matlab software tools. The result of the simulation was contrasted with the reality and it was possible to improve the stability of the terminal voltage, successfully. The facility belongs to ARN (Argentina) and, in principle, it was installed to development an AMS system. (author)

  8. Materials science symposium 'heavy ion science in tandem energy region'

    Iwamoto, Akira; Yoshida, Tadashi; Takeuchi, Suehiro

    2001-11-01

    The facility of the JAERI tandem accelerator and its booster has been contributing to obtain plenty of fruitful results in the fields of nuclear physics, nuclear chemistry, atomic and solid state physics and materials science, taking an advantage of its prominent performances of heavy ion acceleration. The previous meeting held in 1999 also offered an opportunity to scientists from all over the heavy ion science fields, including nuclear physics, solid state physics and cross-field physics to have active discussions. This meeting included oral presentations with a new plan and with a new scope of fields expected from now on, as an occasion for opening the 21st century in heavy ion science. The 50 of the presented papers are indexed individually. (J.P.N.)

  9. Energy calibration of the 3 MV tandem accelerator

    Bunnak, S; Mizuhashi, K; Tajima, S

    1996-12-01

    By this study, a graphite calorimeter has been developed to measure the average ion energy from electrostatic ion accelerator (3 MV Tandem Ion Accelerator of the Takasaki Ion Accelerators for Advanced Radiation Application). A graphite calorimeter was designed for measuring the ion beam energy in wide ion energy ranges (from 3 MeV to 10 MeV). By a couple of this study, the {sup 1} H({sup 15} N, {alpha} {gamma}) {sup 12} C resonant nuclear reactions (resonant energy 6.385 MeV and 13.355 MeV) has been applied for measuring the absolute ion beam energy serve as a comparative method. The obtained results were compared in terms of resolution and accuracy. Close agreement was found for both methods, the deviation was observed within {+-} 3%

  10. United theory of planet formation (i): Tandem regime

    Ebisuzaki, Toshikazu; Imaeda, Yusuke

    2017-07-01

    The present paper is the first one of a series of papers that present the new united theory of planet formation, which includes magneto-rotational instability and porous aggregation of solid particles in an consistent way. We here describe the ;tandem; planet formation regime, in which a solar system like planetary systems are likely to be produced. We have obtained a steady-state, 1-D model of the accretion disk of a protostar taking into account the magneto-rotational instability (MRI) and and porous aggregation of solid particles. We find that the disk is divided into an outer turbulent region (OTR), a MRI suppressed region (MSR), and an inner turbulent region (ITR). The outer turbulent region is fully turbulent because of MRI. However, in the range, rout(= 8 - 60 AU) from the central star, MRI is suppressed around the midplane of the gas disk and a quiet area without turbulence appears, because the degree of ionization of gas becomes low enough. The disk becomes fully turbulent again in the range rin(= 0.2 - 1 AU), which is called the inner turbulent region, because the midplane temperature become high enough (>1000 K) due to gravitational energy release. Planetesimals are formed through gravitational instability at the outer and inner MRI fronts (the boundaries between the MRI suppressed region (MSR) and the outer and inner turbuent regions) without particle enhancement in the original nebula composition, because of the radial concentration of the solid particles. At the outer MRI front, icy particles grow through low-velocity collisions into porous aggregates with low densities (down to ∼10-5 gcm-3). They eventually undergo gravitational instability to form icy planetesimals. On the other hand, rocky particles accumulate at the inner MRI front, since their drift velocities turn outward due to the local maximum in gas pressure. They undergo gravitational instability in a sub-disk of pebbles to form rocky planetesimals at the inner MRI front. They are likely

  11. Research on optimizing pass schedule of tandem cold mill

    Lu, C.; Wang, J.S.; Zhao, Q.L.; Liu, X.H.; Wang, G.D.

    2000-01-01

    In this paper, research on pass schedule of tandem cold mill (TCM) is carried out. According to load (reduction, rolling force, motor power) balance, non-linear equations set with variables of inter-stand thickness is constructed. The pass schedule optimization is carried out by solving the non-linear equations set. As the traditional method, the Newton-Raphson method is used for solving the non-linear equations set. In this paper a new simple method is brought up. On basis of the monotone relations between thickness and load, the inter-stands thickness is adjusted dynamically. The solution of non-linear equations set can be converged by iterative calculation. This method can avoid the derivative calculation used by traditional method. So, this method is simple and calculation speed is high. It is suitable for on-line control. (author)

  12. Physics issues in mirror and tandem mirror systems

    Post, R.F.

    1984-01-01

    Over the years the study of the confinement of high temperature plasma in magnetic mirror systems has presented researchers with many unusual physics problems. Many of these issues are by now understood theoretically and documented experimentally. With the advent of the tandem mirror idea, some new issues have emerged and are now under intensive study. These include: (1) the generation and control of ambipolar confining potentials and their effect on axial confinement and, (2) the combined influence of nonaxisymmetric magnetic fields (used to ensure MHD stability) and electric magnetic particle drifts on radial transport. Physics considerations associated with these two categories of issues will be reviewed, including concepts for the control of radial transport, under study or proposed

  13. Tandem mirror magnet system for the mirror fusion test facility

    Bulmer, R.H.; Van Sant, J.H.

    1980-01-01

    The Tandem Mirror Fusion Test Facility (MFTF-B) will be a large magnetic fusion experimental facility containing 22 supercounducting magnets including solenoids and C-coils. State-of-the-art technology will be used extensively to complete this facility before 1985. Niobium titanium superconductor and stainless steel structural cases will be the principle materials of construction. Cooling will be pool boiling and thermosiphon flow of 4.5 K liquid helium. Combined weight of the magnets will be over 1500 tonnes and the stored energy will be over 1600 MJ. Magnetic field strength in some coils will be more than 8 T. Detail design of the magnet system will begin early 1981. Basic requirements and conceptual design are disclosed in this paper

  14. Potential measurement and radial transport in GAMMA 10 tandem mirror

    Ishii, K.; Katanuma, I.; Segawa, T.; Ohkawara, H.; Mase, A.; Miyoshi, S.

    1989-01-01

    GAMMA 10 is an effectively axisymmetric tandem mirror with thermal barriers. Potential information is important to investigate the plasma confinement. The barrier and central space potentials are determined by means of two gold neutral beam probes. Two-dimensional potential profiles have been measured in the barrier cell. In GAMMA 10, to assure magneto-hydrodynamic (MHD) stability, the nonaxisymmetric minimum-B mirror cells are contained between the central-solenoid and the plug/barrier cells at the ends of the machine. From the point of view of neoclassical resonant-plateau transport in circular equipotential contours, this effective axisymmetrization is successful. The measured potential profiles are slightly elongated during the onset of ω ce ECRH. In this paper we report the beam probe potential measurement, the neoclassical ion radial transport in the noncircular equipotential surface and the thermal barrier potential. (author) 6 refs., 5 figs

  15. Structural Basis of Actin Filament Nucleation by Tandem W Domains

    Chen, Xiaorui; Ni, Fengyun; Tian, Xia; Kondrashkina, Elena; Wang, Qinghua; Ma, Jianpeng

    2013-01-01

    SUMMARY Spontaneous nucleation of actin is very inefficient in cells. To overcome this barrier, cells have evolved a set of actin filament nucleators to promote rapid nucleation and polymerization in response to specific stimuli. However, the molecular mechanism of actin nucleation remains poorly understood. This is hindered largely by the fact that actin nucleus, once formed, rapidly polymerizes into filament, thus making it impossible to capture stable multisubunit actin nucleus. Here, we report an effective double-mutant strategy to stabilize actin nucleus by preventing further polymerization. Employing this strategy, we solved the crystal structure of AMPPNP-actin in complex with the first two tandem W domains of Cordon-bleu (Cobl), a potent actin filament nucleator. Further sequence comparison and functional studies suggest that the nucleation mechanism of Cobl is probably shared by the p53 cofactor JMY, but not Spire. Moreover, the double-mutant strategy opens the way for atomic mechanistic study of actin nucleation and polymerization. PMID:23727244

  16. An RF heated tandem mirror plasma propulsion study

    Yang, T. F.; Yao, X.; Peng, S.; Krueger, W. A.; Chang-Diaz, F. R.

    1989-01-01

    Experimental results on a tandem mirror hybrid plume rocket involving a three-stage system of plasma injection, heating, and subsequent injection through a magnetic nozzle are presented. In the experiments, a plasma is created by breaking down the gas with electron cyclotron resonance heating at 2 kW in the central cell, and the ion species is then heated to high temperatures with ion cyclotron resonance heating at 10 kW in the end cell. A Langmuir probe measured an electron density of 2.5 x 10 to the 16th/cu m and a temperature of 100 eV in the central cell and an ion density of 1.25 x 10 to the 17th/cu m and a temperature of 500 eV in the end cell.

  17. Preliminary pellet injection experiment in the Gamma 10 tandem mirror

    Kawamori, Eiichirou; Tamano, Teruo; Nakashima, Yousuke; Yoshikawa, Masayuki; Kobayashi, Shinji; Cho, Teruji; Ishii, Kameo; Yatsu, Kiyoshi [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan); Mase, Atsushi [Advanced Sceince and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka (Japan)

    2000-07-01

    In the GAMMA 10 tandem mirror, pellet injection experiments have been started as a solution for the density limit problem. This is the first pellet injection experiment in open systems. We describe the possibilities of confinement of pellet fueled particles. For that, we measure the number of end loss particles and compare them with pellet fueled ones in various conditions of confining potentials. The deterioration of confining potential with the pellet injection is a fundamental issue. The results show that the ion confining potential recover faster than central electron temperature due to thermal barrier. We also consider the operating space for fueling method. It is demonstrated that the operating space for pellet injection exceeds gas fueled one on hot ion mode plasmas. (author)

  18. Pebble bed blanket design for deuterium burning tandem mirror reactors

    Grotz, S.P.; Dhir, V.K.

    1983-01-01

    The UCLA tandem mirror reactor, SATYR, was developed around the capability of tandem mirrors with thermal barriers to burn deuterium at reasonable efficiency levels. The pebble bed concept has been incorporated into our blanket design for the following reasons: 1) Large area-to-volume ratio for purposes of heat removal; 2) Large volume of structure for high thermal capacity thus increasing the safety margin during off-normal incidents; 3) Relatively inexpensive manufacturing costs because of large acceptable tolerances and lack of exotic materials (i.e., lithium). A simplified stress analysis of the blanket module was performed to optimize and simplify the design. The pre-specified stress intensity limitations used were based upon a 30-year predicted lifetime for each module. Along with stress analysis of the vessel a detailed thermal hydraulic analysis of the pebble bed has been completed. Parameters affecting the pebble bed design are fluidization velocity, pressure drop, heat transfer coefficient, thermally induced stress in the spheres and spatial variation of the power density. Although reasonable gross thermal efficiencies of the 2 designs has been achieved (28% for H 2 O and 39% for He) the high net recirculating power fraction for heating and neutral beams results in relatively low net plant efficiencies (21% and 27%). The results show that a blanket can be designed with good thermal efficiency and a relative-ly simple configuration. However, application of this concept to the high Q deuterium-tritium fuel cycle would have difficulties resulting from the need for continuous removal of the tritium. (orig./HP)

  19. TANDEM - French-German cooperation for local energy transition

    Mouchard, Claire; Garreau, Enora; Maurer, Christiane; Schilken, Peter; Keilmann, Jenny-Claire; Janssen, Ulrike

    2014-01-01

    The simultaneous implementation of the German 'Energiewende' and the French 'Transition energetique' prompted both country's governments to sign various cooperation agreements. As both 'Energiewende' and 'Transition energetique' put a strong focus on decentralization of energy supply, establishing close inter-communal cooperation is particularly promising. The project TANDEM, which is jointly led by Klima-Buendnis and Energy Cities - both local authority networks - and co-funded by Germany's Federal Environment Agency (UBA) and the French Energy Agency ADEME provides French and German local authorities with a unique opportunity to exchange experiences and create partnerships for climate protection having the following objectives: - Creating broad mutual understanding for the respective situation, challenges and framework in energy and climate policy; - Encourage exchanges with regard to obstacles and success factors concerning the realization of ambitious energy- and climate-goals and promoting mutual transfer of know-how; - Stimulating close collaboration between local authorities from both countries while involving and supporting local stakeholders and citizens; - Implementing initial stages of cooperation projects during the lifetime of the TANDEM project and creating a foundation for long-term cooperation; - Raise awareness for demands, requirements and concerns of local authorities on a national and European level in order to strengthen their influence and enlarge their scope of action. In this document, the authors briefly present the French, German and European contexts and the organization of both countries regarding energy transition. Then, a parallel is made between the national energy-climate plans of both countries ('Klimaschutzkonzepte' and 'Plans Climat-Energie Territoriaux') to identify the similarities and differences in order to learn from each other and to be able to create cooperations between both policy mechanisms

  20. Multifactorial Understanding of Ion Abundance in Tandem Mass Spectrometry Experiments.

    Fazal, Zeeshan; Southey, Bruce R; Sweedler, Jonathan V; Rodriguez-Zas, Sandra L

    2013-01-29

    In a bottom-up shotgun approach, the proteins of a mixture are enzymatically digested, separated, and analyzed via tandem mass spectrometry. The mass spectra relating fragment ion intensities (abundance) to the mass-to-charge are used to deduce the amino acid sequence and identify the peptides and proteins. The variables that influence intensity were characterized using a multi-factorial mixed-effects model, a ten-fold cross-validation, and stepwise feature selection on 6,352,528 fragment ions from 61,543 peptide ions. Intensity was higher in fragment ions that did not have neutral mass loss relative to any mass loss or that had a +1 charge state. Peptide ions classified for proton mobility as non-mobile had lowest intensity of all mobility levels. Higher basic residue (arginine, lysine or histidine) counts in the peptide ion and low counts in the fragment ion were associated with lower fragment ion intensities. Higher counts of proline in peptide and fragment ions were associated with lower intensities. These results are consistent with the mobile proton theory. Opposite trends between peptide and fragment ion counts and intensity may be due to the different impact of factor under consideration at different stages of the MS/MS experiment or to the different distribution of observations across peptide and fragment ion levels. Presence of basic residues at all three positions next to the fragmentation site was associated with lower fragment ion intensity. The presence of proline proximal to the fragmentation site enhanced fragmentation and had the opposite trend when located distant from the site. A positive association between fragment ion intensity and presence of sulfur residues (cysteine and methionine) on the vicinity of the fragmentation site was identified. These results highlight the multi-factorial nature of fragment ion intensity and could improve the algorithms for peptide identification and the simulation in tandem mass spectrometry experiments.

  1. Tunable color parallel tandem organic light emitting devices with carbon nanotube and metallic sheet interlayers

    Oliva, Jorge; Desirena, Haggeo; De la Rosa, Elder [Centro de Investigaciones en Optica, A.P. 1-948, León, Guanajuato 37160 (Mexico); Papadimitratos, Alexios [Solarno Inc., Coppell, Texas 75019 (United States); University of Texas at Dallas, Richardson, Texas 75080 (United States); Zakhidov, Anvar A., E-mail: Zakhidov@utdallas.edu [Solarno Inc., Coppell, Texas 75019 (United States); University of Texas at Dallas, Richardson, Texas 75080 (United States); Energy Efficiency Center, National University of Science and Technology, MISiS, Moscow 119049 (Russian Federation)

    2015-11-21

    Parallel tandem organic light emitting devices (OLEDs) were fabricated with transparent multiwall carbon nanotube sheets (MWCNT) and thin metal films (Al, Ag) as interlayers. In parallel monolithic tandem architecture, the MWCNT (or metallic films) interlayers are an active electrode which injects similar charges into subunits. In the case of parallel tandems with common anode (C.A.) of this study, holes are injected into top and bottom subunits from the common interlayer electrode; whereas in the configuration of common cathode (C.C.), electrons are injected into the top and bottom subunits. Both subunits of the tandem can thus be monolithically connected functionally in an active structure in which each subunit can be electrically addressed separately. Our tandem OLEDs have a polymer as emitter in the bottom subunit and a small molecule emitter in the top subunit. We also compared the performance of the parallel tandem with that of in series and the additional advantages of the parallel architecture over the in-series were: tunable chromaticity, lower voltage operation, and higher brightness. Finally, we demonstrate that processing of the MWCNT sheets as a common anode in parallel tandems is an easy and low cost process, since their integration as electrodes in OLEDs is achieved by simple dry lamination process.

  2. DNA Damage by Ionizing Radiation: Tandem Double Lesions by Charged Particles

    Huo, Winifred M.; Chaban, Galina M.; Wang, Dunyou; Dateo, Christopher E.

    2005-01-01

    Oxidative damages by ionizing radiation are the source of radiation-induced carcinogenesis, damage to the central nervous system, lowering of the immune response, as well as other radiation-induced damages to human health. Monte Carlo track simulations and kinetic modeling of radiation damages to the DNA employ available molecular and cellular data to simulate the biological effect of high and low LET radiation io the DNA. While the simulations predict single and double strand breaks and base damages, so far all complex lesions are the result of stochastic coincidence from independent processes. Tandem double lesions have not yet been taken into account. Unlike the standard double lesions that are produced by two separate attacks by charged particles or radicals, tandem double lesions are produced by one single attack. The standard double lesions dominate at the high dosage regime. On the other hand, tandem double lesions do not depend on stochastic coincidences and become important at the low dosage regime of particular interest to NASA. Tandem double lesions by hydroxyl radical attack of guanine in isolated DNA have been reported at a dosage of radiation as low as 10 Gy. The formation of two tandem base lesions was found to be linear with the applied doses, a characteristic of tandem lesions. However, tandem double lesions from attack by a charged particle have not been reported.

  3. Targeted tandem duplication of a large chromosomal segment in Aspergillus oryzae.

    Takahashi, Tadashi; Sato, Atsushi; Ogawa, Masahiro; Hanya, Yoshiki; Oguma, Tetsuya

    2014-08-01

    We describe here the first successful construction of a targeted tandem duplication of a large chromosomal segment in Aspergillus oryzae. The targeted tandem chromosomal duplication was achieved by using strains that had a 5'-deleted pyrG upstream of the region targeted for tandem chromosomal duplication and a 3'-deleted pyrG downstream of the target region. Consequently,strains bearing a 210-kb targeted tandem chromosomal duplication near the centromeric region of chromosome 8 and strains bearing a targeted tandem chromosomal duplication of a 700-kb region of chromosome 2 were successfully constructed. The strains bearing the tandem chromosomal duplication were efficiently obtained from the regenerated protoplast of the parental strains. However, the generation of the chromosomal duplication did not depend on the introduction of double-stranded breaks(DSBs) by I-SceI. The chromosomal duplications of these strains were stably maintained after five generations of culture under nonselective conditions. The strains bearing the tandem chromosomal duplication in the 700-kb region of chromosome 2 showed highly increased protease activity in solid-state culture, indicating that the duplication of large chromosomal segments could be a useful new breeding technology and gene analysis method.

  4. UV-induced tandem double mutations in the trpA gene of E. coli

    Piechocki, R.; Langhammer, R.

    1980-01-01

    The ultraviolet light induction of tandem double mutations in a reverse mutation system was shown using trpA mutants which are characterized by the codon sequences GAA and AAG in codon position 211. Among 597 Trp + independent revertants of the trpA (AAG211) strain 3 full revertants were detected arising from UV-induced tandem double base exchanges. In the codon unit 211 full revertants due to single base exchanges are at least 20 times as frequent as full revertants due to tandem double base exchanges. (author)

  5. Life cycle analysis of organic tandem solar cells: When are they warranted?

    Espinosa Martinez, Nieves; Krebs, Frederik C

    2014-01-01

    in their making when compared with the single junction solar cell has to be justified and compensated by a higher efficiency. A central question to ask is how much energy you need to invest in a system in order for it to produce energy and return the investment at least once and preferably a number of times....... As an initial investigation into the potential viability of the tandem or multi-junction approach we have engaged in a detailed analysis based on the manufacturing energy for each step within the tandem module supply chain for full ambient processing of thin flexible polymer tandem solar cells prepared entirely...

  6. Heavy-atom neutral beams for tandem-mirror end plugs

    Post, D.E.; Grisham, L.R.; Santarius, J.F.; Emmert, G.A.

    1981-05-01

    The advantages of neutral beams with Z greater than or equal to 3 formed from negative ions, accelerated to 0.5 to 1.0 MeV/amu, and neutralized with high efficiency, are investigated for use in tandem mirror reactor end plugs. These beams can produce Q's of 20 to 30, and thus can replace the currently proposed 200 to 500 keV neutral proton beams presently planned for tandem mirror reactors. Thus, these Z greater than or equal to 3 neutral beams increase the potential attractiveness of tandem mirror reactors by offering a substitute for difficult high energy neutral hydrogen end plug beams

  7. On the Relativistic Correction of Particles Trajectory in Tandem Type Electrostatic Accelerator

    Minárik Stanislav

    2015-08-01

    Full Text Available A constant potential is applied to the acceleration of the ion-beam in the tandem type electrostatic accelerator. However, not just one voltage is applied, but instead a number of applications can be made in succession by means of the tandem arrangement of high voltage tubes. This number of voltage applications, which is the number of so-called "stages" of a tandem accelerator, may be two, three, or four, depending on the chosen design. Electrostatic field with approximately constant intensity acts on ions in any stage.

  8. Roll-to-roll processed polymer tandem solar cells partially processed from water

    Larsen-Olsen, Thue Trofod; Andersen, Thomas Rieks; Andreasen, Birgitta

    2012-01-01

    Large area polymer tandem solar cells completely processed using roll-to-roll (R2R) coating and printing techniques are demonstrated. A stable tandem structure was achieved by the use of orthogonal ink solvents for the coating of all layers, including both active layers. Processing solvents...... included water, alcohols and chlorobenzene. Open-circuit voltages close to the expected sum of sub cell voltages were achieved, while the overall efficiency of the tandem cells was found to be limited by the low yielding back cell, which was processed from water based ink. Many of the challenges associated...

  9. TMX-U [Tandem Mirror Experiment-Upgrade]: Final report, Volume 2

    Porter, G.D.

    1988-01-01

    This paper discusses the plasma control and the physics accomplishments of the Tandem Mirror Experiment-Upgrade. This particular volume discusses fueling, ion heating, Fokker-Planck modeling, plasma stability and technical development. 270 refs

  10. Semi-transparent perovskite solar cells for tandems with silicon and CIGS

    Bailie, Colin D.

    2015-01-01

    © 2015 The Royal Society of Chemistry. A promising approach for upgrading the performance of an established low-bandgap solar technology without adding much cost is to deposit a high bandgap polycrystalline semiconductor on top to make a tandem solar cell. We use a transparent silver nanowire electrode on perovskite solar cells to achieve a semi-transparent device. We place the semi-transparent cell in a mechanically-stacked tandem configuration onto copper indium gallium diselenide (CIGS) and low-quality multicrystalline silicon (Si) to achieve solid-state polycrystalline tandem solar cells with a net improvement in efficiency over the bottom cell alone. This work paves the way for integrating perovskites into a low-cost and high-efficiency (>25%) tandem cell.

  11. Air-processed organic tandem solar cells on glass: toward competitive operating lifetimes

    Adams, Jens; Spyropoulos, George D.; Salvador, Michael

    2015-01-01

    efficiencies of more than 10% the rather limited stability of this type of devices raises concerns towards future commercialization. The tandem concept allows for both absorbing a broader range of the solar spectrum and reducing thermalization losses. We designed an organic tandem solar cell with an inverted...... device geometry comprising environmentally stable active and charge-selecting layers. Under continuous white light irradiation, we demonstrate an extrapolated, operating lifetime in excess of one decade. We elucidate that for the current generation of organic tandem cells one critical requirement...... for long operating lifetimes consists of periodic UV light treatment. These results suggest that new material approaches towards UV-resilient active and interfacial layers may enable efficient organic tandem solar cells with lifetimes competitive with traditional inorganic photovoltaics....

  12. Hybrid tandem solar cells with depleted-heterojunction quantum dot and polymer bulk heterojunction subcells

    Kim, Taesoo

    2015-10-01

    We investigate hybrid tandem solar cells that rely on the combination of solution-processed depleted-heterojunction colloidal quantum dot (CQD) and bulk heterojunction polymer:fullerene subcells. The hybrid tandem solar cell is monolithically integrated and electrically connected in series with a suitable p-n recombination layer that includes metal oxides and a conjugated polyelectrolyte. We discuss the monolithic integration of the subcells, taking into account solvent interactions with underlayers and associated constraints on the tandem architecture, and show that an adequate device configuration consists of a low bandgap CQD bottom cell and a high bandgap polymer:fullerene top cell. Once we optimize the recombination layer and individual subcells, the hybrid tandem device reaches a VOC of 1.3V, approaching the sum of the individual subcell voltages. An impressive fill factor of 70% is achieved, further confirming that the subcells are efficiently connected via an appropriate recombination layer. © 2015.

  13. Maximizing tandem solar cell power extraction using a three-terminal design

    Warren, Emily L. [National Renewable Energy Lab; USA; Deceglie, Michael G. [National Renewable Energy Lab; USA; Rienäcker, Michael [Institute for Solar Energy Research Hamelin; Germany; Peibst, Robby [Institute for Solar Energy Research Hamelin; Germany; Tamboli, Adele C. [National Renewable Energy Lab; USA; Stradins, Paul [National Renewable Energy Lab; USA

    2018-01-01

    Three-terminal tandem solar cells can provide a robust operating mechanism to efficiently capture the solar spectrum without the need to current match sub-cells or fabricate complicated metal interconnects.

  14. TMX-U [Tandem Mirror Experiment-Upgrade]: Final report, Volume 1

    Porter, G.D.

    1988-01-01

    This paper discusses the plasma control and the physics accomplishments of the Tandem Mirror Experiment-Upgrade. This particular volume discusses potential measurements, plasma confinement, and hot electron and ion physics. 230 refs

  15. Ion cyclotron resonant heating 2 x 1700 loop antenna for the Tandem Mirror Experiment-Upgrade

    Brooksby, C.A.; Ferguson, S.W.; Molvik, A.W.; Barter, J.

    1985-01-01

    This paper reviews the mechanical design and improvements that have taken place on the loop type ion cyclotron resonance heating (ICRH) antennas that are located in the center cell region of the Tandem Mirror Experiment-Upgrade (TMX-U)

  16. Tandem malonate-based glucosides (TMGs) for membrane protein structural studies

    Hussain, Hazrat; Mortensen, Jonas S.; Du, Yang

    2017-01-01

    class of glucoside amphiphiles, designated tandem malonate-based glucosides (TMGs). A few TMG agents proved effective at both stabilizing a range of membrane proteins and extracting proteins from the membrane environment. These favourable characteristics, along with synthetic convenience, indicate...

  17. Design and long-term monitoring of DSC/CIGS tandem solar module

    Vildanova, M F; Nikolskaia, A B; Kozlov, S S; Shevaleevskiy, O I

    2015-01-01

    This paper describes the design and development of tandem dye-sensitized/Cu(In, Ga)Se (DSC/CIGS) PV modules. The tandem PV module comprised of the top DSC module and a bottom commercial 0,8 m 2 CIGS module. The top DSC module was made of 10 DSC mini-modules with the field size of 20 × 20 cm 2 each. Tandem DSC/CIGS PV modules were used for providing the long-term monitoring of energy yield and electrical parameters in comparison with standalone CIGS modules under outdoor conditions. The outdoor test facility, containing solar modules of both types and a measurement unit, was located on the roof of the Institute of Biochemical Physics in Moscow. The data obtained during monitoring within the 2014 year period has shown the advantages of the designed tandem DSC/CIGS PV-modules over the conventional CIGS modules, especially for cloudy weather and low-intensity irradiation conditions. (paper)

  18. Synfuels from fusion: producing hydrogen with the Tandem Mirror Reactor and thermochemical cycles

    Werner, R.W.; Ribe, F.L.

    1981-01-21

    This volume contains the following sections: (1) the Tandem Mirror fusion driver, (2) the Cauldron blanket module, (3) the flowing microsphere, (4) coupling the reactor to the process, (5) the thermochemical cycles, and (6) chemical reactors and process units. (MOW)

  19. Interpreting the need for initial support to perform tandem stance tests of balance

    Hile, E.S.; Brach, J.S.; Perera, S.; Wert, D.M.; VanSwearingen, J.M.; Studenski, S.A.

    2012-01-01

    BACKGROUND: Geriatric rehabilitation reimbursement increasingly requires documented deficits on standardized measures. Tandem stance performance can characterize balance, but protocols are not standardized. Objective The purpose of this study was to explore the impact of: (1) initial support to

  20. Low driving voltage simplified tandem organic light-emitting devices by using exciplex-forming hosts

    Zhou, Dong-Ying; Cui, Lin-Song; Zhang, Ying-Jie; Liao, Liang-Sheng; Aziz, Hany

    2014-10-01

    Tandem organic light-emitting devices (OLEDs), i.e., OLEDs containing multiple electroluminescence (EL) units that are vertically stacked, are attracting significant interest because of their ability to realize high current efficiency and long operational lifetime. However, stacking multiple EL units in tandem OLEDs increases driving voltage and complicates fabrication process relative to their standard single unit counterparts. In this paper, we demonstrate low driving voltage tandem OLEDs via utilizing exciplex-forming hosts in the EL units instead of conventional host materials. The use of exciplex-forming hosts reduces the charge injection barriers and the trapping of charges on guest molecules, resulting in the lower driving voltage. The use of exciplex-forming hosts also allows using fewer layers, hence simpler EL configuration which is beneficial for reducing the fabrication complexity of tandem OLEDs.

  1. Semi-transparent perovskite solar cells for tandems with silicon and CIGS

    Bailie, Colin D.; Christoforo, M. Greyson; Mailoa, Jonathan P.; Bowring, Andrea R.; Unger, Eva L.; Nguyen, William H.; Burschka, Julian; Pellet, Norman; Lee, Jungwoo Z.; Grä tzel, Michael; Noufi, Rommel; Buonassisi, Tonio; Salleo, Alberto; McGehee, Michael D.

    2015-01-01

    solar cell. We use a transparent silver nanowire electrode on perovskite solar cells to achieve a semi-transparent device. We place the semi-transparent cell in a mechanically-stacked tandem configuration onto copper indium gallium diselenide (CIGS

  2. Neoclassical resonant-plateau transport in the noncircular equipotential surface of a tandem mirror

    Katanuma, I.; Kiwamoto, Y.; Ishii, K.; Yatsu, K.; Miyoshi, S.

    1988-07-01

    Neoclassical resonant-plateau transport in a minimum-B anchored tandem mirror is calculated in an experimentally observed case that a magnetic flux tube of an equipotential contours is not circular at the central cell. (author)

  3. Neoclassical resonant-plateau transport in the noncircular equipotential surface of a tandem mirror

    Katanuma, I.; Kiwamoto, Y.; Ishii, K.; Yatsu, K.; Miyoshi, S.

    1989-01-01

    Neoclassical resonant-plateau transport in a minimum-B anchored tandem mirror is calculated in an experimentally observed case where a flux tube of equipotential contours is not circular at the central cell

  4. Tools for analyzing genetic variants from sequencing data Case study: short tandem repeats

    Gymrek, Melissa

    2016-01-01

    This was presented as a BitesizeBio Webinar entitled "Tools for analyzing genetic variants from sequencing data Case study: short tandem repeats"Accompanying scripts can be accessed on github:https://github.com/mgymrek/mgymrek-bitesizebio-webinar 

  5. Synfuels from fusion: producing hydrogen with the Tandem Mirror Reactor and thermochemical cycles

    Werner, R.W.; Ribe, F.L.

    1981-01-01

    This volume contains the following sections: (1) the Tandem Mirror fusion driver, (2) the Cauldron blanket module, (3) the flowing microsphere, (4) coupling the reactor to the process, (5) the thermochemical cycles, and (6) chemical reactors and process units

  6. Unexpected formation of 2,1-benzisothiazol-3-ones from oxathiolano ketenimines: a rare tandem process.

    Alajarin, Mateo; Bonillo, Baltasar; Sanchez-Andrada, Pilar; Vidal, Angel; Bautista, Delia

    2009-03-19

    A rare one-pot reaction, a tandem [1,5]-H shift/1,5 electrocyclization/[3 + 2] cycloreversion process, leading from N-[2-(1,3-oxathiolan-2-yl)]phenyl ketenimines to 1-(beta-styryl)-2,1-benzisothiazol-3-ones and ethylene, is disclosed and mechanistically unraveled by means of a computational DFT study. The two latter stages of the tandem process are calculated to occur in a single mechanistic step via a transition structure of pseudopericyclic characteristics.

  7. Equipment and performance of the Q3D spectrometer installed at the tandem laboratory of Saclay

    Berthier, B.

    1979-01-01

    A quadrupole - dipole - dipole - dipole (Q3D) magnetic spectrometer with proportional gas counter which has been installed at the tandem laboratory of Saclay is described. Typical results are given indicating the performance of the apparatus in studies of heavy ion reactions at tandem energies for which good energy resolution and large solid angles are required. Improvements to allow the detection of heavier masses and less energetic ions with better energy resolution are planned. (U.K.)

  8. Annual report of Tandem Accelerator Center, University of Tsukuba, for fiscal 1975

    1976-01-01

    Tandem Accelerator Center (TAC) is a research center of the University of Tsukuba established mainly for interdisciplinary research. Its principal apparatus is a 12 UD Pelletron tandem accelerator of which assembling was completed in fiscal 1975. Activities of the TAC for the period of April 1975 to March 1976 are reported: accelerator and beam transport system, general equipments, equipment development, and heavy-ion reactions. (Mori, K.)

  9. Annual report of Tandem Accelerator Center, University of Tsukuba, for fiscal 1976

    1977-01-01

    A research center of the University of Tsukuba, Tandem Accelerator Center (TAC) has a 12 UD Pelletron tandem accelerator as its principal apparatus; of which acceptance test was finished in July 1976. Activities of the TAC for the period of April 1976 to March 1977 are reported: accelerator and beam transport system, general equipments, equipment development, nuclear physics, chemistry, and biological and medical Science. (Mori, K.)

  10. A new modified tandem appliance for management of developing Class III malocclusion

    Sukh, Ram; Singh, Gyan P; Tandon, Pradeep

    2013-01-01

    Most developing Class III patients display a retruded maxilla. Early intervention in mixed dentition is associated with better patient compliance and possibly a better orthopedic response, which can produce favorable results. The aim of this article is to present the fabrication of the new modified tandem appliance and its use in management of developing Class III malocclusion. The therapeutic results of a new modified tandem appliance are presented in an 8 year-old male patient with anterior...

  11. Characterization of cationic glycoporphyrins by electrospray tandem mass spectrometry.

    Silva, Eduarda M P; Serra, Vanda Vaz; Ribeiro, Anderson O; Tomé, João P C; Domingues, Pedro; Faustino, M Amparo F; Neves, M Graça P M S; Tomé, Augusto C; Cavaleiro, José A S; Ferrer-Correia, António J; Iamamoto, Yassuko; Domingues, M Rosário M

    2006-01-01

    Novel cationic porphyrin derivatives having a galactose or a bis(isopropylidene)galactose unit linked directly to a pyridine or to an aminophenyl group were characterized by electrospray tandem mass spectrometry (ESI-MS/MS). The electrospray mass spectra (ESI-MS) show the M(+) ions, since these porphyrins are already monocharged in solution. The fragmentation of these ions under ESI-MS/MS conditions was studied and it was found that elimination of the sugar residue as a radical (-163 or -243 Da) is a common fragmentation pathway. Loss of the sugar unit as a neutral fragment (-162 or -242 Da) and cross-ring fragmentations typical of glyco-derivatives are also observed for the pyridinium glycoporphyrins, but they are absent in the case of ammonium glycoporphyrins. The cationic beta-pyridiniumvinyl porphyrins show an atypical fragmentation due to the cleavage of the C(5)-C(6) bond of the sugar unit. Overall, the different patterns of fragmentation observed in the ESI-MS/MS spectra of the sugar pyridinium porphyrins and of the sugar ammonium phenyl porphyrins can give important information about the type of spacer between the porphyrin and the sugar unit. Copyright (c) 2006 John Wiley & Sons, Ltd.

  12. Tandem Gravimetric and Volumetric Apparatus for Methane Sorption Measurements

    Burress, Jacob; Bethea, Donald

    Concerns about global climate change have driven the search for alternative fuels. Natural gas (NG, methane) is a cleaner fuel than gasoline and abundantly available due to hydraulic fracturing. One hurdle to the adoption of NG vehicles is the bulky cylindrical storage vessels needed to store the NG at high pressures (3600 psi, 250 bar). The adsorption of methane in microporous materials can store large amounts of methane at low enough pressures for the allowance of conformable, ``flat'' pressure vessels. The measurement of the amount of gas stored in sorbent materials is typically done by measuring pressure differences (volumetric, manometric) or masses (gravimetric). Volumetric instruments of the Sievert type have uncertainties that compound with each additional measurement. Therefore, the highest-pressure measurement has the largest uncertainty. Gravimetric instruments don't have that drawback, but can have issues with buoyancy corrections. An instrument will be presented with which methane adsorption measurements can be performed using both volumetric and gravimetric methods in tandem. The gravimetric method presented has no buoyancy corrections and low uncertainty. Therefore, the gravimetric measurements can be performed throughout an entire isotherm or just at the extrema to verify the results from the volumetric measurements. Results from methane sorption measurements on an activated carbon (MSC-30) and a metal-organic framework (Cu-BTC, HKUST-1, MOF-199) will be shown. New recommendations for calculations of gas uptake and uncertainty measurements will be discussed.

  13. Personal computer control system for small size tandem accelerator

    Takayama, Hiroshi; Kawano, Kazuhiro; Shinozaki, Masataka [Nissin - High Voltage Co. Ltd., Kyoto (Japan)

    1996-12-01

    As the analysis apparatus using tandem accelerator has a lot of control parameter, numbers of control parts set on control panel are so many to make the panel more complex and its operativity worse. In order to improve these faults, development and design of a control system using personal computer for the control panel mainly constituted by conventional hardware parts were tried. Their predominant characteristics are shown as follows: (1) To make the control panel construction simpler and more compact, because the hardware device on the panel surface becomes the smallest limit as required by using a personal computer for man-machine interface. (2) To make control speed more rapid, because sequence control is closed within each block by driving accelerator system to each block and installing local station of the sequencer network at each block. (3) To make expandability larger, because of few improvement of the present hardware by interrupting the sequencer local station into the net and correcting image of the computer when increasing a new beamline. And, (4) to make control system cheaper, because of cheaper investment and easier programming by using the personal computer. (G.K.)

  14. Probabilistic consensus scoring improves tandem mass spectrometry peptide identification.

    Nahnsen, Sven; Bertsch, Andreas; Rahnenführer, Jörg; Nordheim, Alfred; Kohlbacher, Oliver

    2011-08-05

    Database search is a standard technique for identifying peptides from their tandem mass spectra. To increase the number of correctly identified peptides, we suggest a probabilistic framework that allows the combination of scores from different search engines into a joint consensus score. Central to the approach is a novel method to estimate scores for peptides not found by an individual search engine. This approach allows the estimation of p-values for each candidate peptide and their combination across all search engines. The consensus approach works better than any single search engine across all different instrument types considered in this study. Improvements vary strongly from platform to platform and from search engine to search engine. Compared to the industry standard MASCOT, our approach can identify up to 60% more peptides. The software for consensus predictions is implemented in C++ as part of OpenMS, a software framework for mass spectrometry. The source code is available in the current development version of OpenMS and can easily be used as a command line application or via a graphical pipeline designer TOPPAS.

  15. Vacuum vessel for the tandem Mirror Fusion Test Facility

    Gerich, J.W.

    1986-01-01

    In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10 -8 torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200-m 3 internal volume) has been fabricated and erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system

  16. Tandem ion mobility spectrometry coupled to laser excitation

    Simon, Anne-Laure; Choi, Chang Min; Clavier, Christian; Barbaire, Marc; Maurelli, Jacques; Dagany, Xavier; MacAleese, Luke; Dugourd, Philippe, E-mail: philippe.dugourd@univ-lyon1.fr [Institut Lumière Matière, Université de Lyon, Université Lyon 1-CNRS, 69622 Villeurbanne cedex (France); Chirot, Fabien [Institut des Sciences Analytiques, Université de Lyon, Université Lyon 1-CNRS, 69622 Villeurbanne cedex (France)

    2015-09-15

    This manuscript describes a new experimental setup that allows to perform tandem ion mobility spectrometry (IMS) measurements and which is coupled to a high resolution time-of-flight mass spectrometer. It consists of two 79 cm long drift tubes connected by a dual ion funnel assembly. The setup was built to permit laser irradiation of the ions in the transfer region between the two drift tubes. This geometry allows selecting ions according to their ion mobility in the first drift tube, to irradiate selected ions, and examine the ion mobility of the product ions in the second drift tube. Activation by collision is possible in the same region (between the two tubes) and between the second tube and the time-of-flight. IMS-IMS experiments on Ubiquitin are reported. We selected a given isomer of charge state +7 and explored its structural rearrangement following collisional activation between the two drift tubes. An example of IMS-laser-IMS experiment is reported on eosin Y, where laser irradiation was used to produce radical ions by electron photodetachment starting from doubly deprotonated species. This allowed measuring the collision cross section of the radical photo-product, which cannot be directly produced with an electrospray source.

  17. LLNL Tandem Mirror Experiment (TMX) upgrade vacuum system

    Pickles, W.L.; Chargin, A.K.; Drake, R.P.

    1981-01-01

    TMX Upgrade is a large, tandem, magnetic-mirror fusion experiment with stringent requirements on base pressure (10 -8 torr), low H reflux from the first walls, and peak gas pressure (5 x 10 -7 torr) due to neutral beam gas during plasma operation. The 225 m 3 vacuum vessel is initially evacuated by turbopumps. Cryopumps provide a continuous sink for gases other than helium, deuterium, and hydrogen. The neutral beam system introduces up to 480 l/s of H or D. The hydrogen isotopes are pumped at very high speed by titanium sublimed onto two cylindrical radially separated stainless steel quilted liners with a total surface area of 540 m 2 . These surfaces (when cooled to about 80 0 K) provide a pumping speed of 6 x 10 7 l/s for hydrogen. The titanium getter system is programmable and is used for heating as well as gettering. The inner plasma liner can be operated at elevated temperatures to enhance migration of gases away from the surfaces close to the plasma. Glow discharge cleaning is part of the pumpdown procedure. The design features are discussed in conjunction with the operating procedures developed to manage the dynamic vacuum conditions

  18. Alpha-induced instabilities in tandem thermal barriers

    Kammash, T.; Galbraith, D.L.

    1987-01-01

    A major premise in the operation of Tandem Mirror reactors is that the fusion reactions take place in the central cell only. The alpha particles generated by the Deuterium-Tritium (DT) fusions, along with other ions, will however pass from the central cell to the thermal barriers and return to the central cell as a result of reflection by the potential hills that exist by the plugs' side of these barriers. This streaming motion gives rise to electrostatic and electomagnetic instabilities which could detract from the barrier's function as a thermal insulator. The number density and streaming velocity of these passing particles are dictated by the electrostatic potential variation and the magnetic field structure in these regions. It is shown that, in the absence of alphas, barriers with deep potential depression are less susceptible to electrostatic instabilities while particularly vulnerable to unstable electromagnetic modes. In the presence of alphas, especially the fast alphas whose mean energy is significantly larger than the barrier potentials they see, (which is twice as high as that seen by the ions) both types of modes become unstable.

  19. 36Cl-AMS measurements with 3-MV tandem accelerator

    Wang Huijuan; Guan Yongjing; Zhang Wei; Jiang Shan; Ming He

    2013-01-01

    36 C- is one of the most interesting nuclides in accelerator mass spectrometry (AMS) measurements. The application of 36 Cl has been widely applied in various fields. All most all of 36 Cl AMS measurements at natural isotopic concentrations have yet been performed at tandem accelerator with 5 MV or higher terminal voltage. The measure improvement of 36 Cl and other medium heavy isotopes performed at 3 MV in AMS facilities is one of the hottest topics in AMS measurements. In order to increase the suppression factor of 36 S, the energy loss straggling and angular straggling of 36 Cl and 36 S ions in various counter gases (P10, isobutane and propane) were investigated. Some groundwater samples were measured with energy of 32 MeV, and the results were in good agreement with the result obtained with ion energy of 72 MeV. The results indicate that the approximate detection limit of 36 Cl in 3 MV AMS facility is 36 Cl/Cl=1 × 10 -14 , and the uncertainty is 30% when the sample with isotopic ration 36 Cl/Cl≈10 -13 . (authors)

  20. Baking of tandem accelerator tube by low voltage arc discharge

    Nakajima, Yutaka

    1982-01-01

    In designing the accelerating tube for a static tandem accelerator in Kyushu University, the basic policy was as described below: individual unit composing the accelerating tube should fully withstand the electric field of 2 MV/m, and electric discharge must not be propagated from one unit to the adjacent unit when these are assembled to the accelerating tube. The accelerating tube units are each 25 cm in length, and both high and low energy sides are composed of 20 units, respectively. Although about 10 -9 Torr vacuum was obtained at the both ends of the accelerating tube by baking the tube at 300 to 350 deg C with electric heaters wound outside the tube in the conventional method, vast outgas was generated, which decreased vacuum by two or three figures if breakdown occurred through the intermediary of outgas. As a method of positively outgassing and cleaning the electrodes inside the accelerating tube, it was attempted to directly bake all the electrodes in the accelerating tube by causing strong arc discharge flowing H 2 gas in the tube. As a result of considering the conditions for this method, the low voltage arc discharge was employed using oxide cathodes. Thus, after implementing 10A arc discharge for several hours, the voltage was able to be raised to 10 MV almost immediately after the vacuum recovery, and further, after another conditioning for several hours, it was successful to raise voltage up to 11 MV. (Wakatsuki, Y.)

  1. Annual report of the Tandem Accelerator Center, University of Tsukuba

    1990-07-01

    This Annual Report covers the research activities and the technical developments of the Tandem Accelerator Center, University of Tsukuba, for the period from April 1989 to March 1990. Laborious but promising work of refreshing 12UD has continued throughout the year, in the intervals of the regular machine-time service. The terminal voltage of 12UD has gone beyond 12MV. At the time of writing this manuscript, 12UD is running up stably around 12.4MV, the loss current being essentially zero. She has recovered and further begins to flesh up without a surgical operation of grafting 'compressed tubes'. In the course of conditioning, the voltage has reached to 12.78MV. In spite of the considerable time consumed by the refreshing, the total machine-time has exceeded 2,000 hours. In addition to the improvement of 12UD, activities at the Center covered a wide area of research field, viz. 1) nuclear spectroscopy of transitional nuclei, 2) heavy ion fusion and fission processes, 3) polarization phenomena in nuclear reactions, 4) charge exchange process in atomic collisions, 5) application of energetic heavy ions investigating solid-state physics, and 6) effect of ion-irradiation on the fatigue properties of metal. Theoretical work pertinent to the nuclear structure is also included in this report. (author)

  2. Tandem mass spectrometric analysis of cyclophosphamide, ifosfamide and their metabolites.

    Liu, Zhongfa; Chan, Kenneth K; Wang, Jeffrey J

    2005-01-01

    A detailed multi-stage (MSn) fragmentation study of cyclophosphamide (CP), ifosfamide (IF) and their major metabolites, using an ion-trap mass spectrometer and a Q-TOF mass spectrometer, was performed with the aid of specifically deuterium-labeled analogs. The analytes showed good responses in positive-ion electrospray mass spectrometry as [MH]+ ions. Tandem mass spectra revealed a wealth of structurally specific ions, allowing characterization of the fragmentation pathways of these analytes. The major fragmentation pathways of the protonated CP and IF are elimination of ethylene from C5 and C6 of 1,3,2-oxazaphosphorine-2-oxide via a McLafferty rearrangement, and cleavage of the P-N bond. However, their activated 4-OOH and 4-OH metabolites primarily underwent hydrogen peroxide elimination and dehydration, respectively, followed by fragmentation pathways similar to those of CP and IF. These results should prove useful in structural elucidation of future analogs of CP and IF, and/or of their metabolites. Copyright (c) 2005 John Wiley & Sons, Ltd.

  3. Potential formation in axisymmetrized tandem mirror GAMMA 10

    Cho, T.; Ichimura, M.; Inutake, M.

    1985-01-01

    The paper reports experimental results on potential formation and end plugging in the axisymmetrized tandem mirror GAMMA 10. The plugging at both ends has been achieved by a combination of neutral beams and gyrotrons. The presence of a plug potential with a thermal barrier in an axisymmetric mirror has been confirmed by direct measurement of the axial potential profile. Enhancement of axial particle confinement has been observed during the end plugging. Non-ambipolar radial transport has been greatly reduced in the axisymmetrized magnetic configuration. The potentials measured by beam probes and end loss analysers are 0.7, 0.4 and 1.1 kV in the central, barrier and plug regions, respectively. Strong end plugging is observed when the central-cell density is higher than the densities in the plug and the barrier, and the plug density remains higher than the barrier density. The plug electron temperature is higher than the central temperature. Hot electrons forming a football-shaped profile have been stably produced in the axisymmetric mirror. The beta value and the fraction of the hot electrons reach up to 5% and 0.8, respectively. Central-cell ion-cyclotron resonance heating can sustain a stable plasma with higher density and ion temperature when resonance surfaces exist in both the anchor and the central cells. (author)

  4. Perovskite Solar Cells for High-Efficiency Tandems

    McGehee, Michael [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Buonassisi, Tonio [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-09-30

    The first monolithic perovskite/silicon tandem was made with a diffused silicon p-n junction, a tunnel junction made of n++ hydrogenated amorphous silicon, a titania electron transport layer, a methylammonium lead iodide absorber, and a Spiro-OMeTAD hole transport layer (HTL). The power conversion efficiency (PCE) was only 13.7% due to excessive parasitic absorption of light in the HTL, limiting the matched current density to 11.5 mA/cm2. Werner et al.15 raised the PCE to a record 21.2% by switching to a silicon heterojunction bottom cell and carefully tuning layer thicknesses to achieve lower optical loss and a higher current density of 15.9 mA/cm2. It is clear from these reports that minimizing parasitic absorption in the window layers is crucial to achieving higher current densities and efficiencies in monolithic tandems. To this end, the window layers through which light first passes before entering the perovskite and silicon absorber materials must be highly transparent. The front electrode must also be conductive to carry current laterally across the top of the device. Indium tin oxide (ITO) is widely utilized as a transparent electrode in optoelectronic devices such as flat-panel displays, smart windows, organic light-emitting diodes, and solar cells due to its high conductivity and broadband transparency. ITO is typically deposited through magnetron sputtering; however, the high kinetic energy of sputtered particles can damage underlying layers. In perovskite solar cells, a sputter buffer layer is required to protect the perovskite and organic carrier extraction layers from damage during sputter deposition. The ideal buffer layer should also be energetically well aligned so as to act as a carrier-selective contact, have a wide bandgap to enable high optical transmission, and have no reaction with the halides in the perovskite. Additionally, this buffer layer should act as a diffusion barrier layer to prevent both

  5. EXTRACTION OF BUILIDNG SHAPE FROM TANDEM-X DATA

    A. Thiele

    2013-05-01

    Full Text Available Large scale mapping and modeling of urban areas is requested in many fields, especially in planning of energy supply and for change detection. For this purpose, SAR systems are highly attractive due to their independency of daytime and weather. The new satellite configuration of TerraSAR-X and TanDEM-X provides single-pass 3D mapping of the earth with unprecedented geometric resolution, allowing for improved detection and extraction of building positions and shapes. In this paper, single-pass interferograms of the TanDEM-X mission are utilized to automatically reconstruct buildings. To this purpose, first an interferogram is calculated from a TanDEM pair. Then, a new detector is applied that analyses phase ramps in the interferogram. Phase ramps being a pattern typically observable in layover areas of buildings, the detector is able to indicate building locations. Afterwards, the detected building areas are analyzed in more detail to extract width, length, and height of the buildings. Last, an edge detector is applied to deduce the building shapes. The reconstruction results are compared with reference data.

  6. Annual report of the Tandem Accelerator Center, University of Tsukuba

    1983-01-01

    The 12 UD Pelletron tandem accelerator has been operated for seven years without serious trouble since the first beam was obtained in February, 1976. In the last year, the tank was opened five times for minor repair, but the operation of 3977 hours has been attained. The construction of a heavy ion post accelerator with interdigital-H type structure has been continued. The research works described in this report were carried out mainly using the beam from a Lamb-shift type polarized ion source or a sputtering ion source. To the Lamb-shift type polarized ion source, a fast spin-reversal system was newly added, and successfully tested. In the sputtering ion source, the beam intensity was increased. A combination of an ionization chamber and a position-sensitive solid state detector was tested to be used for the study on heavy ion nuclear reaction. The characteristics of avalanche along the anode wire in a gas counter were studied. The accelerator and experimental facilities, the development of experimental equipment, and the researches on nuclear physics, atomic and solid state physics, and biological and medical science are reported. (Kako, I.)

  7. Annual report of the Tandem Accelerator Center, University of Tsukuba

    1989-07-01

    This Annual Report covers the research activities and the technical developments of the Tandem Accelerator Center, University of Tsukuba, for the period from April 1988 to March 1989. Laborious work of refreshing 12UD has continued throughout the year, in parallel with the regular machine-time service. Almost 95% of the work has been completed by the end of March 1989. At the time of writing this manuscript, 12UD is running up modestly beyond 11.0MV, raising joyous murmur of pellet chains. She has recovered up to the hilt. In spite of the considerable time consumed by the refreshing, the total machine-time has exceeded 3,000 hours. Activities at the Center covered a wide area of research field, viz. 1) nuclear spectroscopy of transitional nuclei, 2) heavy ion fusion and fission processes, 3) polarization phenomena in nuclear reactions, 4) charge exchange process in atomic collisions, 5) application of energetic heavy ions to investigating solid-state physics, and 6) effect of ion-irradiation on the fatigue properties of metal. Theoretical work pertinent to the nuclear structure is also included in this report. Prospects for a project attempting to equip the Center with a crystal-ball spectrometer is, at least, not gloomy. First streaks of light seems to begin glimmering. (author)

  8. Materials science symposium 'heavy ion science in tandem energy region'

    Ikezoe, Hiroshi; Yoshida, Tadashi; Takeuchi, Suehiro

    2003-10-01

    The facility of the JAERI tandem accelerator and its booster has been contributing to advancing heavy ion science researches in the fields of nuclear physics, nuclear chemistry, atomic and solid state physics and materials science, taking advantage of its prominent performances in providing various heavy ions. This meeting, as well as the previous ones held twice, offered scientists from the fields of heavy ion science, including nuclear physics, solid-state physics and cross-field physics, an opportunity to have active discussions among them, as well as to review their research accomplishments in the last two years. Oral presentations were selected from a wider scope of prospective fields, expecting a new step of advancing in heavy ion science. Main topics of the meeting were the status of the JAERI-KEK joint project of developing a radioactive nuclear beam (RNB) facility and research programs related to the RNB. This meeting was held at Advanced Science Research Center in JAERI-Tokai on January 8th and 9th in 2003, and successfully carried out with as many as 190 participants and a lot of sincere discussions. The proceedings are presented in this report. The 51 of the presented papers are indexed individually. (J.P.N.)

  9. Newborn screening by tandem mass spectrometry: ethical and social issues.

    Avard, Denise; Vallance, Hilary; Greenberg, Cheryl; Potter, Beth

    2007-01-01

    Emerging technologies like Tandem Mass Spectrometry (TMS) enable multiple tests on a single blood sample and allow the expansion of Newborn Screening (NBS) to include various metabolic diseases. Introducing TMS for NBS raises important social and ethical questions: what are the criteria for adding disorders to screening panels? What evidence justifies expansion of screening? How can equity in NBS access and standards be ensured? How can policy standards be set, given the multiplicity of stakeholders? To address emerging issues, policy-makers, patient advocates, clinicians and researchers had a workshop during the 2005 Garrod Symposium. The participants received a summary of the discussion and understood the workshop's goal was to provide a basis for further discussion. This article contributes to this ongoing discussion. Several proposed recommendations assert the centrality of including social and ethical issues in the assessment of whether or not to introduce TMS. The article outlines five key recommendations for advancing the NBS agenda: national public health leadership; transparency; increased national consistency in NBS strategy, including minimum standards; collaboration between the federal and provincial/territorial governments and diverse stakeholders; and supporting research and/or programs based on effectiveness, which integrate ethical and social issues into assessment.

  10. Electrospray ionization tandem mass spectrometry of ammonium cationized polyethers.

    Nasioudis, Andreas; Heeren, Ron M A; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F

    2011-05-01

    Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers. © American Society for Mass Spectrometry, 2011

  11. WITAMIR-I: A tandem mirror power reactor

    Emmert, G.A.; Kulcinski, G.L.; Beyer, J.B.

    1983-01-01

    A conceptual design of a near term commercial tandem mirror power reactor will be presented. The basic configuration utilizes Yin-yang minimum B end plugs with inboard thermal barriers, which are pumped by neutral beam injection. The maximum magnetic fields are 6.1 T, 8.1 T and 15 T in the central cell, Yin-yang, and thermal barrier magnets, respectively. The blanket utilizes Pb 83 Li 17 as the coolant and breeder, and HT-9 as the structural material. This configuration yields a high energy multiplication (1.37), a sufficient tritium breeding ratio (1.07) and has a major advantage with respect to maintenance. A single stage direct convertor is used at one end and an electron thermal dump at the other end. The plasma Q is 28 at a fusion power level of 3000 MWsub(th); the net electrical output is 1530 MWe and the overall efficiency is 39%. Cost estimates indicate that WITAMIR-I is competitive with recent tokamak power reactor designs. (author)

  12. Rapid comparison of diacetylmorphine on banknotes by tandem mass spectrometry.

    Ebejer, Karl A; Brereton, Richard G; Carter, James F; Ollerton, Samantha L; Sleeman, Richard

    2005-01-01

    A procedure is described for the determination of the distribution of the contamination of banknotes with controlled drugs using tandem mass spectrometry. The method is illustrated using diacetylmorphine, which is the major active component of heroin. A series of banknotes is introduced into the mass spectrometer and the intensities of two product ions (m/z 328 and 268) derived from the precursor protonated molecule (m/z 370) are recorded. A banknote is considered contaminated if it shows a significant peak for both product ions, and if the ratio of intensities of these two peaks falls within accepted limits. The distribution of diacetylmorphine on sterling banknotes taken from general circulation within the UK can be modelled by an arcsin (square root) transformation of the data or by a log transformation of the data with a higher proportion of contamination. The two models were found to be in close agreement, predicting an upper limit (at 99.9% confidence) of contamination on banknotes from general circulation between 9 and 10%. The percentage contamination in a case study was calculated and compared to the background distribution using the two models proposed. This comparison revealed that the contamination present in the case study was inconsistent with that present on banknotes in general circulation. (c) 2005 John Wiley & Sons, Ltd.

  13. Installation of a tandem-type accelerator mass spectrometer

    Mizushima, Toshihiko; Togawa, Orihiko; Mizutani, Yoshihiko; Yamamoto, Tadatoshi

    2000-02-01

    Tandem-type accelerator mass spectrometer (hereinafter referred to as Tandetron) was installed at the Ominato Facility of Mutsu Establishment, JAERI in April, 1997. The objective of its installation is to investigate the mechanism of the mixing and circulation of seawater in the ocean, by collecting seawater samples around Japan and analyzing the horizontal and vertical distributions of 14 C contained in the samples. The Tandetron consists of two lines to measure isotopic ratios of carbon and those of heavier iodine. The adjustment for the carbon line was finished and the measurements of seawater samples were started. The iodine line, on the other hand, is on the final step of its adjustment and performance tests are being carried out with a TOF (Time of Flight) detector. The iodine line will be used to analyze 129 I released from a spent nuclear fuel reprocessing plant and other nuclear facilities. In this report, we summarize the status of installation of the carbon and iodine lines for the Tandetron. The report describes the situations of their adjustments until now, the outline of the Tandetron, tests of measurement performance, evaluation and inspection of shielding performance, problems and their solutions, and so on. (author)

  14. 3002 Humidified Tandem Differential Mobility Analyzer Instrument Handbook

    Uin, Janek [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The Brechtel Manufacturing Inc. (BMI) Humidified Tandem Differential Mobility Analyzer (HT-DMA Model 3002) (Brechtel and Kreidenweis 2000a,b, Henning et al. 2005, Xerxes et al. 2014) measures how aerosol particles of different initial dry sizes grow or shrink when exposed to changing relative humidity (RH) conditions. It uses two different mobility analyzers (DMA) and a humidification system to make the measurements. One DMA selects a narrow size range of dry aerosol particles, which are exposed to varying RH conditions in the humidification system. The second (humidified) DMA scans the particle size distribution output from the humidification system. Scanning a wide range of particle sizes enables the second DMA to measure changes in size or growth factor (growth factor = humidified size/dry size), due to water uptake by the particles. A Condensation Particle Counter (CPC) downstream of the second DMA counts particles as a function of selected size in order to obtain the number size distribution of particles exposed to different RH conditions.

  15. Screening of carnitine and biotin deficiencies on tandem mass spectrometry.

    Hagiwara, Shin-Ichiro; Kubota, Mitsuru; Nambu, Ryusuke; Kagimoto, Seiichi

    2017-04-01

    It is important to assess pediatric patients for nutritional deficiency when they are receiving specific interventions, such as enteral feeding. We focused on measurement of C0 and 3-hydroxyisovalerylcarnitine (C5-OH) with tandem mass spectrometry (MS/MS), which is performed as part of the newborn mass screening. The purpose of this study was to investigate the usefulness of MS/MS for screening carnitine and biotin deficiencies. Forty-two children (24 boys, 18 girls) were enrolled between December 2013 and December 2015. Blood tests, including measurement of serum free carnitine via the enzyme cycling method, and acylcarnitine analysis on MS/MS of dried blood spot (DBS), were performed for the evaluation of nutrition status. Median patient age was 2 years (range, 2 months-14 years). Mean serum free carnitine was 41.8 ± 19.2 μmol/L. In six of the 42 patients, serum free carnitine was 1.00 nmol/L. Therapy-resistant eczema was improved by treatment with additional biotin and a non-hydrolyzed formula. C0 and C5-OH, measured on MS/MS of DBS, were useful for screening carnitine and biotin deficiencies. © 2016 Japan Pediatric Society.

  16. Visualization of tandem repeat mutagenesis in Bacillus subtilis.

    Dormeyer, Miriam; Lentes, Sabine; Ballin, Patrick; Wilkens, Markus; Klumpp, Stefan; Kohlheyer, Dietrich; Stannek, Lorena; Grünberger, Alexander; Commichau, Fabian M

    2018-03-01

    Mutations are crucial for the emergence and evolution of proteins with novel functions, and thus for the diversity of life. Tandem repeats (TRs) are mutational hot spots that are present in the genomes of all organisms. Understanding the molecular mechanism underlying TR mutagenesis at the level of single cells requires the development of mutation reporter systems. Here, we present a mutation reporter system that is suitable to visualize mutagenesis of TRs occurring in single cells of the Gram-positive model bacterium Bacillus subtilis using microfluidic single-cell cultivation. The system allows measuring the elimination of TR units due to growth rate recovery. The cultivation of bacteria carrying the mutation reporter system in microfluidic chambers allowed us for the first time to visualize the emergence of a specific mutation at the level of single cells. The application of the mutation reporter system in combination with microfluidics might be helpful to elucidate the molecular mechanism underlying TR (in)stability in bacteria. Moreover, the mutation reporter system might be useful to assess whether mutations occur in response to nutrient starvation. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Fast atom bombardment tandem mass spectrometry of carotenoids

    van Breeman, R.B. [Univ. of Illinois, Chicago, IL (United States); Schmitz, H.H.; Schwartz, S.J. [North Carolina State Univ., Raleigh, NC (United States)

    1995-02-01

    Positive ion fast atom bombardment (FAB) tandem mass spectrometry (MS-MS) using a double-focusing mass spectrometer with linked scanning at constant B/E and high-energy collisionally activated dissociation (CAD) was used to differentiate 17 different cartenoids, including {beta}-apo-8{prime}- carotenal, astaxanthin, {alpha}-carotene, {beta}-carotene, {gamma}-carotene, {zeta}-carotene, canthaxanthin, {beta}-cryptoxanthin, isozeaxanthin bis (pelargonate), neoxanthin, neurosporene, nonaprene, lutein, lycopene, phytoene, phytofluene, and zeaxanthin. The carotenoids were either synthetic or isolated from plant tissues. The use of FAB ionization minimized degradation or rearrangement of the carotenoid structures due to the inherent thermal instability generally ascribed to these compounds. Instead of protonated molecules, both polar xanthophylls and nonpolar carotenes formed molecular ions, M{sup {center_dot}+}, during FAB ionization. Following collisionally activated dissociation, fragment ions of selected molecular ion precursors showed structural features indicative of the presence of hydroxyl groups, ring systems, ester groups, and aldehyde groups and the extent of aliphatic polyene conjugation. The fragmentation patterns observed in the mass spectra herein may be used as a reference for the structural determination of carotenoids isolated from plant and animal tissues. 18 refs., 4 figs.

  18. Annual report of the Tandem Accelerator Center, University of Tsukuba

    1984-01-01

    The 12 UD Pelletron tandem accelerator was operated very stably through the period covered by this annual report. It was shut down for two weeks to inspect the SF 6 gas transfer system. The construction of a heavy ion post accelerator with interdigital-H structure has been completed, and chlorine ions have been accelerated to 2 MeV per charge. Effort was exerted to develop radiation detectors and a polarimeter. A windowless Si(Li) X-ray detector for PIXE was constructed, and the K X-ray of oxygen was able to be detected with high efficiency. The use of incombustible gas for ionization chambers was tested to detect the heavy ions of low Z and low energy, and nitrogen was available. A time-zero detector for heavy ion mass identification using two microchannel plates and a more elaborate high efficiency gamma detection system with six NaI (Tl) detectors and two Ge(Li) detectors were constructed. VAX 11/750-VAX 11/780 computer system was installed. Most of the research works were conducted, using the beam from the Lamb-shift polarized ion source. The studies on fusion reaction using heavy ions have been continued. The accelerator and experimental facilities, and the researches in the fields of nuclear physics, atomic and solid state physics, and biology and medical science are reported. (Kako, I.)

  19. Robust optimization of a tandem grating solar thermal absorber

    Choi, Jongin; Kim, Mingeon; Kang, Kyeonghwan; Lee, Ikjin; Lee, Bong Jae

    2018-04-01

    Ideal solar thermal absorbers need to have a high value of the spectral absorptance in the broad solar spectrum to utilize the solar radiation effectively. Majority of recent studies about solar thermal absorbers focus on achieving nearly perfect absorption using nanostructures, whose characteristic dimension is smaller than the wavelength of sunlight. However, precise fabrication of such nanostructures is not easy in reality; that is, unavoidable errors always occur to some extent in the dimension of fabricated nanostructures, causing an undesirable deviation of the absorption performance between the designed structure and the actually fabricated one. In order to minimize the variation in the solar absorptance due to the fabrication error, the robust optimization can be performed during the design process. However, the optimization of solar thermal absorber considering all design variables often requires tremendous computational costs to find an optimum combination of design variables with the robustness as well as the high performance. To achieve this goal, we apply the robust optimization using the Kriging method and the genetic algorithm for designing a tandem grating solar absorber. By constructing a surrogate model through the Kriging method, computational cost can be substantially reduced because exact calculation of the performance for every combination of variables is not necessary. Using the surrogate model and the genetic algorithm, we successfully design an effective solar thermal absorber exhibiting a low-level of performance degradation due to the fabrication uncertainty of design variables.

  20. Role of ECRH in potential formation for tandem mirrors

    Rognlien, T.D.; Matsuda, Y.; Stewart, J.J.

    1985-01-01

    The axial ion plugging potential in a tandem mirror is produced by electron cyclotron resonance heating (ECRH) applied at two locations in the end mirror cell. A second harmonic (ω = 2ω/sub c/) resonance is used near the midplane to generate hot electrons which yield an electron potential barrier between center cell electrons and electrons outboard of the end cell midplane. The latter group of electrons is then heated at the fundamental resonance (ω = ω/sub c/) on the outboard side of the magnetic well which drives an ion confining potential. Fokker-Planck and Monte Carlo calculations show that such a configuration is achievable, and the scaling obeys a rather simple set of equations. Another aspect of this configuration is the experimental observation that the fundamental heating drives the overall potential of the device relative to the wall to approx. 1 kV. An analytic model predicts this behavior for very strong ECRH. Results are given a numerical study of electron confinement in a mirror cell owing to fundamental heating as the level of the rf electric field, E/sub rf/, is increased. For the second part of the paper, we show that moderate levels of uniformly distributed rf fields, called cavity fields, can result in very hot (>250 keV) tails in the electron distribution as seen in the TMX-U experiment

  1. TMRBAR power balance code for tandem mirror reactors

    Blackkfield, D.T.; Campbell, R.; Fenstermacher, M.; Bulmer, R.; Perkins, L.; Peng, Y.K.M.; Reid, R.L.; Wu, K.F.

    1984-01-01

    A revised version of the tandem mirror multi-point code TMRBAR developed at LLNL has been used to examine various reactor designs using MARS-like ''c'' coils. We solve 14 to 16 non-linear equations to obtain the densities, temperatures, plasma potential and magnetic field on axis at the cardinal points. Since ICRH, ECRH, and neutral beams may be used to stabilize the central cell, various combinations of rf and neutral beam powers may satisfy the physics. To select a desired set of physics parameters, we use nonlinear optimization techniques. Whit these routines, we minimize or maximize a physics variable subject to the physics constraints being satisfied. For example, for a given fusion power we may find the minimum length needed to have an ignited central cell or the maximum fusion Q. Finally, we have coupled this physics model to the LLNL magnetics-MHD code. This code runs the EFFI magnetic field generator and uses TEBASCO to calculate 1-D MHD equilibria and stability

  2. Annual report of the Tandem Accelerator Center, University of Tsukuba

    Furuno, K.; Shima, K.; Komatsubara, T.

    1992-09-01

    This annual report includes the research activities and the technical developments carried out at the Tandem Accelerator Center in University of Tsukuba for the period from April 1991 to March 1992. Research activities covered the following subjects. Experimental investigations were made on 1) nuclear spectroscopy of high-spin rotational states and high-spin isomers in odd-odd nuclei, anomalous Fermi-coupling constant in the β decay of 35 Ar and the search for new isotopes around the mass number 90; 2) polarization phenomena in nuclear reactions; 3) the application of energetic heavy ions to solid state physics; 4) the properties of defects in metal produced by proton irradiation; 5) the magnetic properties of LiVO 2 by NMR; 6) off line Moessbauer studies; and 7) the mechanism of micro-cluster formation at the surface of material by heavy-ion bombardment. Theoretical work pertinent to the nuclear collective motion and the relativistic mean-field theory is also included in this report. (J.P.N.)

  3. Flow past two tandem square cylinders vibrating transversely in phase

    Mithun, M G; Tiwari, Shaligram

    2014-01-01

    Numerical investigations have been carried out to study the wake characteristics of flow past two tandem square cylinders vibrating in phase. Both the cylinders vibrate in a transverse direction, i.e., perpendicular to the incoming flow with the same frequency and amplitude. The frequency of vibration of the cylinders and the inter-cylinder spacing are varied for fixed values of the Reynolds number (Re = 100) and the amplitude ratio (A/D = 0.4). The synchronous or lock-in regime for the oscillatory wake of the vibrating cylinders has been identified by varying the frequency of the vibration from f e  = 0.4 f 0 to 1.6 f 0 (f 0 being the frequency of vortex shedding behind a stationary square cylinder). The characteristics of lift and drag and the mechanism of vortex shedding are studied by varying the excitation frequency within the lock-in range for each value of inter-cylinder spacing. The complex interaction of flow between the cylinders gives rise to a variety of characteristically different shedding patterns in their wake. For values of inter-cylinder spacing equal to 2D and 3D, periodic, as well as quasi-periodic, lock-in behaviors are observed in the synchronous range. (paper)

  4. Absorbed dose determination in photon fields using the tandem method

    Marques Pachas, J.F.

    1999-01-01

    The purpose of this work is to develop an alternative method to determine the absorbed dose and effective energy of photons with unknown spectral distributions. It includes a 'tandem' system that consists of two thermoluminescent dosemeters with different energetic dependence. LiF: Mg, Ti, CaF 2 : Dy thermoluminescent dosemeters and a Harshaw 3500 reading system are employed. Dosemeters are characterized with 90 Sr- 90 Y, calibrated with the energy of 60 Co and irradiated with seven different qualities of x-ray beams, suggested by ANSI No. 13 and ISO 4037. The answers of each type of dosemeter are adjusted to a function that depends on the effective energy of photons. The adjustment is carried out by means of the Rosenbrock minimization algorithm. The mathematical model used for this function includes five parameters and has a gauss and a straight line. Results show that the analytical functions reproduce the experimental data of the answers, with a margin of error of less than 5%. The reason of the answers of the CaF 2 : Dy and LiF: Mg, Ti, according to the energy of the radiation, allows us to establish the effective energy of photons and the absorbed dose, with a margin of error of less than 10% and 20% respectively

  5. Improved Optics in Monolithic Perovskite/Silicon Tandem Solar Cells with a Nanocrystalline Silicon Recombination Junction

    Sahli, Florent

    2017-10-09

    Perovskite/silicon tandem solar cells are increasingly recognized as promi­sing candidates for next-generation photovoltaics with performance beyond the single-junction limit at potentially low production costs. Current designs for monolithic tandems rely on transparent conductive oxides as an intermediate recombination layer, which lead to optical losses and reduced shunt resistance. An improved recombination junction based on nanocrystalline silicon layers to mitigate these losses is demonstrated. When employed in monolithic perovskite/silicon heterojunction tandem cells with a planar front side, this junction is found to increase the bottom cell photocurrent by more than 1 mA cm−2. In combination with a cesium-based perovskite top cell, this leads to tandem cell power-conversion efficiencies of up to 22.7% obtained from J–V measurements and steady-state efficiencies of up to 22.0% during maximum power point tracking. Thanks to its low lateral conductivity, the nanocrystalline silicon recombination junction enables upscaling of monolithic perovskite/silicon heterojunction tandem cells, resulting in a 12.96 cm2 monolithic tandem cell with a steady-state efficiency of 18%.

  6. Dinuclear Tetrapyrazolyl Palladium Complexes Exhibiting Facile Tandem Transfer Hydrogenation/Suzuki Coupling Reaction of Fluoroarylketone

    Dehury, Niranjan

    2016-07-18

    Herein, we report an unprecedented example of dinuclear pyrazolyl-based Pd complexes exhibiting facile tandem catalysis for fluoroarylketone: Tetrapyrazolyl di-palladium complexes with varying Pd-Pd distances efficiently catalyze the tandem reaction involving transfer hydrogenation of fluoroarylketone to the corresponding alcohol and Suzuki-Miyaura cross coupling reaction of the resulting fluoroarylalcohol under moderate reaction conditions, to biaryl alcohol. The complex with the shortest Pd-Pd distance exhibits the highest tandem activity among its di-metallic analogues, and exceeds in terms of activity and selectivity the analogous mononuclear compound. The kinetics of the reaction indicates clearly that reductive transformation of haloarylketone into haloaryalcohol is the rate determining step in the tandem reaction. Interestingly while fluoroarylketone undergoes the multistep tandem catalysis, the chloro- and bromo-arylketones undergo only a single step C-C coupling reaction resulting in biarylketone as the final product. Unlike the pyrazole based Pd compounds, the precursor PdCl2 and the phosphine based relevant complexes (PPh3)2PdCl2 and (PPh3)4Pd are found to be unable to exhibit the tandem catalysis.

  7. IMPACT OF SOME GEOMETRICAL ASPECTS ON THE TANDEM CO-ROTATING PROPELLER HYDRODYNAMIC CHARACTERISTICS

    Boucetta Djahida

    2017-01-01

    Full Text Available In the present paper, a numerical simulation based on Kω-SST turbulence model has been carried out to determine the tandem propeller hydrodynamic characteristics in non-cavitating viscous flow by using the commercial code Fluent. As the first step, the numerical approach has been applied to the case of single propeller and the comparison with experiment results was in a good agreement. Next, the effects of axial and angular displacement as well as the diameter ratio between the tandem propellers have been investigated. This part of the study reveals that the tandem with idem propeller diameters is strongly recommended to assure more advantages. Furthermore, the tandem geometry corresponding to the axial displacement equal to 0.6D seems to be the best configuration and the open water performances remain almost unchanged with the variation of angular displacement. On the other hand, details of the mutual interaction between tandem propellers were also given by showing pressure contours, streamlines and thrust coefficient. Globally, this study illustrates the advantages of replacing single propellers by tandem solution.

  8. Economic viability of thin-film tandem solar modules in the United States

    Sofia, Sarah E.; Mailoa, Jonathan P.; Weiss, Dirk N.; Stanbery, Billy J.; Buonassisi, Tonio; Peters, I. Marius

    2018-05-01

    Tandem solar cells are more efficient but more expensive per unit area than established single-junction (SJ) solar cells. To understand when specific tandem architectures should be utilized, we evaluate the cost-effectiveness of different II-VI-based thin-film tandem solar cells and compare them to the SJ subcells. Levelized cost of electricity (LCOE) and energy yield are calculated for four technologies: industrial cadmium telluride and copper indium gallium selenide, and their hypothetical two-terminal (series-connected subcells) and four-terminal (electrically independent subcells) tandems, assuming record SJ quality subcells. Different climatic conditions and scales (residential and utility scale) are considered. We show that, for US residential systems with current balance-of-system costs, the four-terminal tandem has the lowest LCOE because of its superior energy yield, even though it has the highest US per watt (US W-1) module cost. For utility-scale systems, the lowest LCOE architecture is the cadmium telluride single junction, the lowest US W-1 module. The two-terminal tandem requires decreased subcell absorber costs to reach competitiveness over the four-terminal one.

  9. Photoemission spectroscopy study on interfacial energy level alignments in tandem organic light-emitting diodes

    Ou, Qing-Dong; Li, Chi; Li, Yan-Qing, E-mail: yqli@suda.edu.cn; Tang, Jian-Xin, E-mail: jxtang@suda.edu.cn

    2015-10-01

    Highlights: • The interface energetics of tandem OLEDs is overviewed. • Energy level alignment in CGLs is addressed via photoemission spectroscopy. • The n-type doping effect with cesium compounds is discussed. • Hole injection barrier is dependent on oxygen vacancies in transition metal oxides. • Device lifetime of tandem OLEDs is sensitive to interfacial stability of CGLs. - Abstract: Organic light-emitting diodes (OLEDs) using a tandem structure offer a highly attractive option for the applications of next-generation flat panel displays and solid-state lighting due to the extremely high brightness and efficiency along with the long operational lifetime. In general, reliable information about interface energetics of the charge generation layers (CGLs), which plays the central role in charge generation and carrier injection into the stacked emission units, is highly desirable and advantageous for interface engineering and the performance optimization of tandem OLEDs. In this review, our recent studies on tandem OLEDs are overviewed, especially from interface energetics perspective via photoemission spectroscopy. The electronic structures of various transition metal oxide (TMO)-based CGLs and their role in charge generation process are reviewed, addressing the n-type doping impact of organic layers in CGLs, thermal annealing-induced oxygen vacancy in TMOs, and the interfacial stability of CGLs on the device operational lifetime. The resulting energy level alignments are summarized in correspondence with tandem OLED performance.

  10. Hybrid tandem photovoltaic devices with a transparent conductive interconnecting recombination layer

    Kim, Taehee; Choi, Jin Young; Jeon, Jun Hong; Kim, Youn-Su; Kim, Bong-Soo; Lee, Doh-Kwon; Kim, Honggon; Han, Seunghee; Kim, Kyungkon

    2012-01-01

    Highlights: ► This work enhanced power conversion efficiency of the hybrid tandem solar cell from 1.0% to 2.6%. ► The interfacial series resistance of the tandem solar cell was eliminated by inserting ITO layer. ► This work shows the feasibility of the highly efficient hybrid tandem solar cells. -- Abstract: We demonstrate hybrid tandem photovoltaic devices with a transparent conductive interconnecting recombination layer. The series-connected hybrid tandem photovoltaic devices were developed by combining hydrogenated amorphous silicon (a-Si:H) and polymer-based organic photovoltaics (OPVs). In order to enhance the interfacial connection between the subcells, we employed highly transparent and conductive indium tin oxide (ITO) thin layer. By using the ITO interconnecting layer, the power conversion efficiency of the hybrid tandem solar cell was enhanced from 1.0% (V OC = 1.041 V, J SC = 2.97 mA/cm 2 , FF = 32.3%) to 2.6% (V OC = 1.336 V, J SC = 4.65 mA/cm 2 , FF = 41.98%) due to the eliminated interfacial series resistance.

  11. Improved Optics in Monolithic Perovskite/Silicon Tandem Solar Cells with a Nanocrystalline Silicon Recombination Junction

    Sahli, Florent; Kamino, Brett A.; Werner, Jé ré mie; Brä uninger, Matthias; Paviet-Salomon, Bertrand; Barraud, Loris; Monnard, Raphaë l; Seif, Johannes Peter; Tomasi, Andrea; Jeangros, Quentin; Hessler-Wyser, Aï cha; De Wolf, Stefaan; Despeisse, Matthieu; Nicolay, Sylvain; Niesen, Bjoern; Ballif, Christophe

    2017-01-01

    Perovskite/silicon tandem solar cells are increasingly recognized as promi­sing candidates for next-generation photovoltaics with performance beyond the single-junction limit at potentially low production costs. Current designs for monolithic tandems rely on transparent conductive oxides as an intermediate recombination layer, which lead to optical losses and reduced shunt resistance. An improved recombination junction based on nanocrystalline silicon layers to mitigate these losses is demonstrated. When employed in monolithic perovskite/silicon heterojunction tandem cells with a planar front side, this junction is found to increase the bottom cell photocurrent by more than 1 mA cm−2. In combination with a cesium-based perovskite top cell, this leads to tandem cell power-conversion efficiencies of up to 22.7% obtained from J–V measurements and steady-state efficiencies of up to 22.0% during maximum power point tracking. Thanks to its low lateral conductivity, the nanocrystalline silicon recombination junction enables upscaling of monolithic perovskite/silicon heterojunction tandem cells, resulting in a 12.96 cm2 monolithic tandem cell with a steady-state efficiency of 18%.

  12. Annual report of Department of Research Reactor and Tandem Accelerator, JFY2012. Operation, utilization and technical development of JRR-3, JRR-4, NSRR, Tandem Accelerator and RI Production Facility

    Murayama, Yoji; Ishii, Tetsuro; Nakamura, Kiyoshi; Uno, Yuki; Ishikuro, Yasuhiro; Kawashima, Kazuhito; Ishizaki, Nobuhiro; Matsumura, Taichi; Nagahori, Kazuhisa; Odauchi, Shouji; Maruo, Takeshi

    2014-03-01

    The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3(Japan Research Reactor No.3), JRR-4(Japan Research Reactor No.4), NSRR(Nuclear Safety Research Reactor), Tandem Accelerator and RI Production Facility. This annual report describes a summary of activities of services and technical developments carried out in the period between April 1, 2012 and March 31, 2013. The activities were categorized into five service/development fields: (1) Operation and maintenance of research reactors and tandem accelerator, (2) Utilization of research reactors and tandem accelerator, (3) Upgrading of utilization techniques of research reactors and tandem accelerator, (4) Safety administration for department of research reactor and tandem accelerator, (5) International cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, number of staff members dispatched to Fukushima for the technical assistance, outcomes in service and technical developments and so on. (author)

  13. Assessment of Genetic Diversity of Zoonotic Brucella spp. Recovered from Livestock in Egypt Using Multiple Locus VNTR Analysis

    Ahmed M. S. Menshawy

    2014-01-01

    Full Text Available Brucellosis is endemic in most parts of Egypt, where it is caused mainly by Brucella melitensis biovar 3, and affects cattle and small ruminants in spite of ongoing efforts devoted to its control. Knowledge of the predominant Brucella species/strains circulating in a region is a prerequisite of a brucellosis control strategy. For this reason a study aiming at the evaluation of the phenotypic and genetic heterogeneity of a panel of 17 Brucella spp. isolates recovered from domestic ruminants (cattle, buffalo, sheep, and goat from four governorates during a period of five years (2002–2007 was carried out using microbiological tests and molecular biology techniques (PCR, MLVA-15, and sequencing. Thirteen strains were identified as B. melitensis biovar 3 while all phenotypic and genetic techniques classified the remaining isolates as B. abortus (n=2 and B. suis biovar 1 (n=2. MLVA-15 yielded a high discriminatory power (h=0.801, indicating a high genetic diversity among the B. melitensis strains circulating among domestic ruminants in Egypt. This is the first report of the isolation of B. suis from cattle in Egypt which, coupled with the finding of B. abortus, suggests a potential role of livestock as reservoirs of several zoonotic Brucella species in the region.

  14. A novel variational Bayes multiple locus Z-statistic for genome-wide association studies with Bayesian model averaging

    Logsdon, Benjamin A.; Carty, Cara L.; Reiner, Alexander P.; Dai, James Y.; Kooperberg, Charles

    2012-01-01

    Motivation: For many complex traits, including height, the majority of variants identified by genome-wide association studies (GWAS) have small effects, leaving a significant proportion of the heritable variation unexplained. Although many penalized multiple regression methodologies have been proposed to increase the power to detect associations for complex genetic architectures, they generally lack mechanisms for false-positive control and diagnostics for model over-fitting. Our methodology is the first penalized multiple regression approach that explicitly controls Type I error rates and provide model over-fitting diagnostics through a novel normally distributed statistic defined for every marker within the GWAS, based on results from a variational Bayes spike regression algorithm. Results: We compare the performance of our method to the lasso and single marker analysis on simulated data and demonstrate that our approach has superior performance in terms of power and Type I error control. In addition, using the Women's Health Initiative (WHI) SNP Health Association Resource (SHARe) GWAS of African-Americans, we show that our method has power to detect additional novel associations with body height. These findings replicate by reaching a stringent cutoff of marginal association in a larger cohort. Availability: An R-package, including an implementation of our variational Bayes spike regression (vBsr) algorithm, is available at http://kooperberg.fhcrc.org/soft.html. Contact: blogsdon@fhcrc.org Supplementary information: Supplementary data are available at Bioinformatics online. PMID:22563072

  15. Single-task and dual-task tandem gait test performance after concussion.

    Howell, David R; Osternig, Louis R; Chou, Li-Shan

    2017-07-01

    To compare single-task and dual-task tandem gait test performance between athletes after concussion with controls on observer-timed, spatio-temporal, and center-of-mass (COM) balance control measurements. Ten participants (19.0±5.5years) were prospectively identified and completed a tandem gait test protocol within 72h of concussion and again 1 week, 2 weeks, 1 month, and 2 months post-injury. Seven uninjured controls (20.0±4.5years) completed the same protocol in similar time increments. Tandem gait test trials were performed with (dual-task) and without (single-task) concurrently performing a cognitive test as whole-body motion analysis was performed. Outcome variables included test completion time, average tandem gait velocity, cadence, and whole-body COM frontal plane displacement. Concussion participants took significantly longer to complete the dual-task tandem gait test than controls throughout the first 2 weeks post-injury (mean time=16.4 [95% CI: 13.4-19.4] vs. 10.1 [95% CI: 6.4-13.7] seconds; p=0.03). Single-task tandem gait times were significantly lower 72h post-injury (p=0.04). Dual-task cadence was significantly lower for concussion participants than controls (89.5 [95% CI: 68.6-110.4] vs. 127.0 [95% CI: 97.4-156.6] steps/minute; p=0.04). Moderately-high to high correlations between tandem gait test time and whole-body COM medial-lateral displacement were detected at each time point during dual-task gait (r s =0.70-0.93; p=0.03-0.001). Adding a cognitive task during the tandem gait test resulted in longer detectable deficits post-concussion compared to the traditional single-task tandem gait test. As a clinical tool to assess dynamic motor function, tandem gait may assist with return to sport decisions after concussion. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  16. Simulation of tandem hydrofoils by finite volume method with moving grid system; Henkei koshi wo tsukatta yugen taisekiho ni yoru tandem suichuyoku no simulation

    Kawashima, H. [Ship Research Inst., Tokyo (Japan); Miyata, H. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

    1996-12-31

    With an objective to clarify possibility of application of time-advancing calculated fluid dynamic (CFD) simulation by using a finite volume method with moving grid system, a simulation was performed on motion of a ship with hydrofoils including the control system therein. The simulation consists of a method that couples a moving grid system technology, an equation of motion, and the control system. Complex interactions between wings and with free surface may be considered automatically by directly deriving fluid force from a flow field by using the CFD. In addition, two-dimensional flows around tandem hydrofoils were calculated to solve the motion problem within a vertical plane. As a result, the following results were obtained: a finite volume method using a dynamic moving grid system method was applied to problems in non-steady tandem hydrofoils to show its usefulness; a method that couples the CFD with the equation of motion was applied to the control problems in the tandem hydrofoils to show possibility of a new technology for simulating motions; and a simulation that considers such wing interference as wave creation, discharged vortices, and associated flows was shown useful to understand characteristics of the tandem hydrofoils. 13 refs., 14 figs.

  17. 6 MV Folded Tandem Ion Accelerator facility at BARC

    Gupta, S.K.

    2010-01-01

    The 6 MV Folded Tandem Ion Accelerator (FOTIA) facility is operational round the clock and accelerated beams of both light and heavy ions are being used extensively by various divisions of BARC, Universities, lIT Bombay and other R and D labs across the country. The FOTIA is an upgraded version of the old 5.5 MV single stage Van-de-Graaff accelerator (1962-1992). Since its commissioning in the year 2000, the poor beam transmission through the 180 deg folding magnet was a matter of concern. A systematic study for beam transmission through the accelerator was carried out and progressive modifications in folding magnet chamber, foil stripper holder and improvement in average vacuum level through the accelerator have resulted in large improvement of beam transmission leading to up to 2.0 micro-amp analyzed proton beams on target. Now the utilization of the beams from the accelerator has increased many folds for basic and applied research in the fields of atomic and nuclear physics, material science and radiation biology etc. Few new beam lines after the indigenously developed 5-port switching magnet are added and the experimental setup for PIXE, PIGE, External PIXE, 4 neutron detector, Proton Induced Positron Annihilation Spectroscopy (PIPAS) setup and the general purpose scattering chamber etc have been commissioned in the beam hall. The same team has developed a Low Energy Accelerator Facility (LEAF) which delivers negative ions of light and heavy ions for application in implantation, irradiation damage studies in semiconductor devices and testing of new beam line components being developed for Low Energy High Intensity Proton Accelerator (LEHIPA) programme at BARC. The LEAF has been developed as stand alone facility and can deliver beam quickly with minimum intervention of the operator. Few more features are being planned to deliver uniform scanned beams on large targets. (author)

  18. Present state of tandem superconductive booster of JAERI

    Takeuchi, Suehiro; Matsuda, Makoto; Kanazawa, Shuhei; Yoshida, Tadashi; Ouchi, Isao; Shoji, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-12-01

    The superconductive booster constructed rear-stage accelerator of the tandem accelerator of the Tokai Research Establishment, JAERI (Japan Atomic Energy Research Institute), was completed in construction of its whole system on October, 1993, and through its beam accelerating test and remodulation its design characteristics were established on September, 1994. From November, 1994 to April, 1995 a repulsion-forming nuclear isolation apparatus was installed to modulate at target room, and was begun to use on June, 1995. The beam reaccelerated at the booster was used mainly for nuclear spectroscopy experiment, a collaborative research was developed using mini-crystal balls made by collecting from University of Tsukuba and so forth. The accelerating part of the booster is a phase independent setting type Linac consisting of 40 niobium superconducting holes with 1/4 wave-length type and 130 MHz in frequency, in which a hole can form 5 MV/m of accelerating electric field for 4 W of radio frequency spent power of 0.75 MV of accelerating voltage per hole, to form 30 MV of voltage in a whole. 4 holes are contained into each 10 cryostats, respectively. In accelerating tests, Si, Cl, Ni, Ge, Ag, I and Au ions are accelerated to establish 30 mV of total accelerating voltage in its design value, which reaches to their expected energy characteristics. Its used days in this year are 25 days after beginning of its use, and operating days of the cooling apparatus was 135 days in total. (G.K.)

  19. TRStalker: an efficient heuristic for finding fuzzy tandem repeats.

    Pellegrini, Marco; Renda, M Elena; Vecchio, Alessio

    2010-06-15

    Genomes in higher eukaryotic organisms contain a substantial amount of repeated sequences. Tandem Repeats (TRs) constitute a large class of repetitive sequences that are originated via phenomena such as replication slippage and are characterized by close spatial contiguity. They play an important role in several molecular regulatory mechanisms, and also in several diseases (e.g. in the group of trinucleotide repeat disorders). While for TRs with a low or medium level of divergence the current methods are rather effective, the problem of detecting TRs with higher divergence (fuzzy TRs) is still open. The detection of fuzzy TRs is propaedeutic to enriching our view of their role in regulatory mechanisms and diseases. Fuzzy TRs are also important as tools to shed light on the evolutionary history of the genome, where higher divergence correlates with more remote duplication events. We have developed an algorithm (christened TRStalker) with the aim of detecting efficiently TRs that are hard to detect because of their inherent fuzziness, due to high levels of base substitutions, insertions and deletions. To attain this goal, we developed heuristics to solve a Steiner version of the problem for which the fuzziness is measured with respect to a motif string not necessarily present in the input string. This problem is akin to the 'generalized median string' that is known to be an NP-hard problem. Experiments with both synthetic and biological sequences demonstrate that our method performs better than current state of the art for fuzzy TRs and that the fuzzy TRs of the type we detect are indeed present in important biological sequences. TRStalker will be integrated in the web-based TRs Discovery Service (TReaDS) at bioalgo.iit.cnr.it. Supplementary data are available at Bioinformatics online.

  20. Profiling of Parkin-binding partners using tandem affinity purification.

    Alessandra Zanon

    Full Text Available Parkinson's disease (PD is a progressive neurodegenerative disorder affecting approximately 1-2% of the general population over age 60. It is characterized by a rather selective loss of dopaminergic neurons in the substantia nigra and the presence of α-synuclein-enriched Lewy body inclusions. Mutations in the Parkin gene (PARK2 are the major cause of autosomal recessive early-onset parkinsonism. The Parkin protein is an E3 ubiquitin ligase with various cellular functions, including the induction of mitophagy upon mitochondrial depolarizaton, but the full repertoire of Parkin-binding proteins remains poorly defined. Here we employed tandem affinity purification interaction screens with subsequent mass spectrometry to profile binding partners of Parkin. Using this approach for two different cell types (HEK293T and SH-SY5Y neuronal cells, we identified a total of 203 candidate Parkin-binding proteins. For the candidate proteins and the proteins known to cause heritable forms of parkinsonism, protein-protein interaction data were derived from public databases, and the associated biological processes and pathways were analyzed and compared. Functional similarity between the candidates and the proteins involved in monogenic parkinsonism was investigated, and additional confirmatory evidence was obtained using published genetic interaction data from Drosophila melanogaster. Based on the results of the different analyses, a prioritization score was assigned to each candidate Parkin-binding protein. Two of the top ranking candidates were tested by co-immunoprecipitation, and interaction to Parkin was confirmed for one of them. New candidates for involvement in cell death processes, protein folding, the fission/fusion machinery, and the mitophagy pathway were identified, which provide a resource for further elucidating Parkin function.

  1. Profiling of Parkin-Binding Partners Using Tandem Affinity Purification

    Blankenburg, Hagen; Doncheva, Nadezhda T.; Schwienbacher, Christine; Serafin, Alice; Alexa, Adrian; Weichenberger, Christian X.; Albrecht, Mario; Klein, Christine; Hicks, Andrew A.; Pramstaller, Peter P.

    2013-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disorder affecting approximately 1–2% of the general population over age 60. It is characterized by a rather selective loss of dopaminergic neurons in the substantia nigra and the presence of α-synuclein-enriched Lewy body inclusions. Mutations in the Parkin gene (PARK2) are the major cause of autosomal recessive early-onset parkinsonism. The Parkin protein is an E3 ubiquitin ligase with various cellular functions, including the induction of mitophagy upon mitochondrial depolarizaton, but the full repertoire of Parkin-binding proteins remains poorly defined. Here we employed tandem affinity purification interaction screens with subsequent mass spectrometry to profile binding partners of Parkin. Using this approach for two different cell types (HEK293T and SH-SY5Y neuronal cells), we identified a total of 203 candidate Parkin-binding proteins. For the candidate proteins and the proteins known to cause heritable forms of parkinsonism, protein-protein interaction data were derived from public databases, and the associated biological processes and pathways were analyzed and compared. Functional similarity between the candidates and the proteins involved in monogenic parkinsonism was investigated, and additional confirmatory evidence was obtained using published genetic interaction data from Drosophila melanogaster. Based on the results of the different analyses, a prioritization score was assigned to each candidate Parkin-binding protein. Two of the top ranking candidates were tested by co-immunoprecipitation, and interaction to Parkin was confirmed for one of them. New candidates for involvement in cell death processes, protein folding, the fission/fusion machinery, and the mitophagy pathway were identified, which provide a resource for further elucidating Parkin function. PMID:24244333

  2. Preliminary design study of the Tandem Mirror Reactor (TMR)

    Moir, R.W.; Barr, W.L.; Carlson, G.A.

    1978-01-01

    This report describes work done in Fiscal Year 1977 by the Fusion Reactor Studies Group of LLL on the conceptual design of a 1000-MW(e) Tandem Mirror Reactor (TMR). The high Q (defined as the ratio of fusion power to injection power) predicted for the TMR (approximately 5) reduces the recirculating power to a nondominant problem and results in an attractive mirror fusion power plant. The fusion plasma of the TMR is contained in the 100-m-long central cell where the magnetic field strength is a modest 2 T. The blanket for neutron energy recovery and tritium breeding is cylindrical and, along with the solenoidal magnet, is divided into 3-m-long modules to facilitate maintenance. The central cell is fueled (but not heated) by the injection of low-energy neutral beams near its ends. Thus, the central cell is simple and of low technology. The end-cell plasmas must be of high density and high energy in order to plug and heat (via the electrons) the central-cell plasma. The present conceptual design uses 1.2-MeV neutral-beam injection for the end plugs and a cryogenic-aluminum, Yin-Yang magnet that produces an incremental field of about 1 T over a field of 16 T produced by a pair of Nb 3 Sn superconducting solenoids. Important design problems remain in both the neutral-beam injector and in the end-plug magnet. Also remaining are important physics questions such as alpha-beam particle transport and end-plug stability. These questions are discussed at length in the report and suggestions for future work are given

  3. Revisiting hyper- and hypo-androgenism by tandem mass spectrometry.

    Fanelli, Flaminia; Gambineri, Alessandra; Mezzullo, Marco; Vicennati, Valentina; Pelusi, Carla; Pasquali, Renato; Pagotto, Uberto

    2013-06-01

    Modern endocrinology is living a critical age of transition as far as laboratory testing and biochemical diagnosis are concerned. Novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for steroid measurement in biological fluids have abundantly demonstrated their analytical superiority over immunometric platforms that until now have dominated the world of steroid hormones determination in clinical laboratories. One of the most useful applications of LC-MS/MS is in the hypogonadism and hyperandrogenism field: LC-MS/MS has proved particularly suitable for the detection of low levels of testosterone typical of women and children, and in general more reliable in accurately determining hypogonadal male levels. This technique also offers increased informative power by allowing multi-analytical profiles that give a more comprehensive picture of the overall hormonal asset. Several LC-MS/MS methods for testosterone have been published in the last decade, some of them included other androgen or more comprehensive steroid profiles. LC-MS/MS offers the concrete possibility of achieving a definitive standardization of testosterone measurements and the generation of widely accepted reference intervals, that will set the basis for a consensus on the diagnostic value of biochemical testing. The present review is aimed at summarizing technological advancements in androgen measurements in serum and saliva. We also provide a picture of the state of advancement of standardization of testosterone assays, of the redefinition of androgen reference intervals by novel assays and of studies using LC-MS/MS for the characterization and diagnosis of female hyperandrogenism and male hypogonadism.

  4. Tandem Mass Spectrometry of Modified and Platinated Oligoribonucleotides

    Nyakas, Adrien; Stucki, Silvan R.; Schürch, Stefan

    2011-05-01

    Therapeutic approaches for treatment of various diseases aim at the interruption of transcription or translation. Modified oligonucleotides, such as 2'- O-methyl- and methylphosphonate-derivatives, exhibit high resistance against cellular nucleases, thus rendering application for, e.g., antigene or antisense purposes possible. Other approaches are based on administration of cross-linking agents, such as cis-diamminedichloroplatinum(II) (cisplatin, DDP), which is still the most widely used anticancer drug worldwide. Due to the formation of 1,2-intrastrand cross links at adjacent guanines, replication of the double-strand is disturbed, thus resulting in significant cytotoxicity. Evidence for the gas-phase dissociation mechanism of platinated RNA is given, based on nano-electrospray ionization high-resolution multistage tandem mass spectrometry (MS n ). Confirmation was found by investigating the fragmentation pattern of platinated and unplatinated 2'-methoxy oligoribonucleotide hexamers and their corresponding methylphosphonate derivatives. Platinated 2'-methoxy oligoribonucleotides exhibit a similar gas-phase dissociation behavior as the corresponding DNA and RNA sequences, with the 3'-C-O bond adjacent to the vicinal guanines being cleaved preferentially, leading to wx-ion formation. By examination of the corresponding platinated methylphosphonate derivatives of the 2'-methoxy oligoribonucleotides, the key role of the negatively charged phosphate oxygen atoms in direct proximity to the guanines was proven. The significant alteration of fragmentation due to platination is demonstrated by comparison of the fragment ion patterns of unplatinated and platinated 2'- O-methyl- and 2'- O-methyl methylphosphonate oligoribonucleotides, and the results obtained by H/D exchange experiments.

  5. Artificial urinary sphincter revision for urethral atrophy: comparing single cuff downsizing and tandem cuff placement

    Brian J. Linder

    Full Text Available ABSTRACT Objective To compare outcomes for single urethral cuff downsizing versus tandem cuff placement during artificial urinary sphincter (AUS revision for urethral atrophy. Materials and Methods We identified 1778 AUS surgeries performed at our institution from 1990-2014. Of these, 406 were first AUS revisions, including 69 revisions for urethral atrophy. Multiple clinical and surgical variables were evaluated for potential association with device outcomes following revision, including surgical revision strategy (downsizing a single urethral cuff versus placing tandem urethral cuffs. Results Of the 69 revision surgeries for urethral atrophy at our institution, 56 (82% were tandem cuff placements, 12 (18% were single cuff downsizings and one was relocation of a single cuff. When comparing tandem cuff placements and single cuff downsizings, the cohorts were similar with regard to age (p=0.98, body-mass index (p=0.95, prior pelvic radiation exposure (p=0.73 and length of follow-up (p=0.12. Notably, there was no difference in 3-year overall device survival compared between single cuff and tandem cuff revisions (60% versus 76%, p=0.94. Likewise, no significant difference was identified for tandem cuff placement (ref. single cuff when evaluating the risk of any tertiary surgery (HR 0.95, 95% CI 0.32-4.12, p=0.94 or urethral erosion/device infection following revision (HR 0.79, 95% CI 0.20-5.22, p=0.77. Conclusions There was no significant difference in overall device survival in patients undergoing single cuff downsizing or tandem cuff placement during AUS revision for urethral atrophy.

  6. Workshop of the JAEA-Tokai Tandem Accelerator. Memorial of 100,000-hour operation

    Ishii, Tetsuro; Osa, Akihiko

    2009-04-01

    Workshop of the JAEA-Tokai tandem accelerator has been held every two years. As a memorial of 100,000-hour operation of the tandem accelerator, we have organized the workshop focusing on the activity at this facility. This workshop covers developments and experiments carried out so far, together with experiments in progress and proposals in future. As previous series of workshops, we offered an opportunity to have active discussion among scientists in different fields including accelerator, nuclear physics, nuclear chemistry, radiation effects, atomic physics and so on, aiming at extending facility and research interactively. As a memorial lecture, we invited Dr. Akira Tonomura of fellow of Hitachi, Ltd, a distinctive scientist for development of electron holography. He delivered a lecture titled 'Structure of magnetic flux observed by electron beam'. He once used the tandem accelerator to induce columnar defects in high-temperature superconductor and studied vortices trapped along the defects. Prof. Shigeru Kubono of University of Tokyo, a chairman of program advisory committee of the tandem accelerator, encouraged us through a talk of 'Expectations for the JAEA-Tokai tandem accelerator'. This workshop was held at Advanced Science Research Center Building in Nuclear Science Research Institute on January 6th and 7th in 2009, having 24 oral presentations and 48 posters, and successfully carried out with as many as 120 participants and a lot of science discussions. This review is the collection of slides of oral presentations. The colored slides can be also found in the home page of the tandem accelerator facility (http://rrsys.tokai-sc.jaea.go.jp/rrsys/html/tandem/index.html). (author)

  7. Band gap engineering of tandem structured CIGS compound absorption layer fabricated by sputtering and selenization

    Kang, San; Sharma, Rahul; Sim, Jae-Kwan [Semiconductor Materials Processing Laboratory, School of Advanced Materials Engineering, College of Engineering, Research Center for Advanced Materials Development (RCAMD), Chonbuk National University, Deokjin-dong 664-14, Jeonju 561-756 (Korea, Republic of); Lee, Cheul-Ro, E-mail: crlee7@jbnu.ac.kr [Semiconductor Materials Processing Laboratory, School of Advanced Materials Engineering, College of Engineering, Research Center for Advanced Materials Development (RCAMD), Chonbuk National University, Deokjin-dong 664-14, Jeonju 561-756 (Korea, Republic of)

    2013-06-25

    Highlights: ► Systematic band gap engineering to fabricate tandem Cu(In,Ga)Se{sub 2} absorption layers. ► XRD shows prominent (1 1 2) reflection shift for attributed CIS, CIGS, and CGS phases. ► Optical transmittance and reflectance spectrum are improved towards infrared region. ► The Cu/In + Ga and Ga/In + Ga effect is matched with highest efficient solar cell. ► Tandem CIS/CIGS/CGS layer, the band gap is increased from 1.15 to 2.06 eV. -- Abstract: Band gap engineering was executed to fabricate a multi-junction stacked i.e. tandem Cu(In,Ga)Se{sub 2} (CIGS) absorption layer. The CIGS absorption layers consist of multi-junction stacked CIS/CIGS/CGS thin films from bottom to top with increasing band gap. Tandem CIGS layers were fabricated by using three precursor of CuIn, In/CuGa/In, and CuGa onto the Mo coated soda-lime glass (SLG) by the sequential sputtering of CuIn, CuGa, and In targets. The CIG precursors were converted into CIGS absorption thin film by selenization process. From the X-ray diffraction (XRD) pattern of CIS/CIGS/CGS tandem layer, with the prominent peak shift for (1 1 2) reflections was attributed to the individual CIS, CIGS, and CGS phases at 26.76°, 27.15°, and 27.65° diffraction angles, respectively. The morphologies and atomic (at%) composition uniformity onto the surface and along the depth were extensively analyzed with field effect scanning electron microscope (FESEM) attached energy dispersive spectroscopy (EDS) and secondary ion mass spectroscopy (SIMS). The optical properties such as transmittance, reflectance and absorbance were found to improve in the infrared region for all the tandem CIGS layers. Near the fundamental absorption edge, the absorption coefficient was approached to 10{sup 5} cm{sup −1} for CIS/CIGS/CGS tandem layer. The straight-line behavior indicates that the films have a direct band gap. The band gap was found to increase from 1.15 to 1.74 eV with the Ga-grading along the depth of individual CIS, CIGS

  8. Band gap engineering of tandem structured CIGS compound absorption layer fabricated by sputtering and selenization

    Kang, San; Sharma, Rahul; Sim, Jae-Kwan; Lee, Cheul-Ro

    2013-01-01

    Highlights: ► Systematic band gap engineering to fabricate tandem Cu(In,Ga)Se 2 absorption layers. ► XRD shows prominent (1 1 2) reflection shift for attributed CIS, CIGS, and CGS phases. ► Optical transmittance and reflectance spectrum are improved towards infrared region. ► The Cu/In + Ga and Ga/In + Ga effect is matched with highest efficient solar cell. ► Tandem CIS/CIGS/CGS layer, the band gap is increased from 1.15 to 2.06 eV. -- Abstract: Band gap engineering was executed to fabricate a multi-junction stacked i.e. tandem Cu(In,Ga)Se 2 (CIGS) absorption layer. The CIGS absorption layers consist of multi-junction stacked CIS/CIGS/CGS thin films from bottom to top with increasing band gap. Tandem CIGS layers were fabricated by using three precursor of CuIn, In/CuGa/In, and CuGa onto the Mo coated soda-lime glass (SLG) by the sequential sputtering of CuIn, CuGa, and In targets. The CIG precursors were converted into CIGS absorption thin film by selenization process. From the X-ray diffraction (XRD) pattern of CIS/CIGS/CGS tandem layer, with the prominent peak shift for (1 1 2) reflections was attributed to the individual CIS, CIGS, and CGS phases at 26.76°, 27.15°, and 27.65° diffraction angles, respectively. The morphologies and atomic (at%) composition uniformity onto the surface and along the depth were extensively analyzed with field effect scanning electron microscope (FESEM) attached energy dispersive spectroscopy (EDS) and secondary ion mass spectroscopy (SIMS). The optical properties such as transmittance, reflectance and absorbance were found to improve in the infrared region for all the tandem CIGS layers. Near the fundamental absorption edge, the absorption coefficient was approached to 10 5 cm −1 for CIS/CIGS/CGS tandem layer. The straight-line behavior indicates that the films have a direct band gap. The band gap was found to increase from 1.15 to 1.74 eV with the Ga-grading along the depth of individual CIS, CIGS, and CGS thin films

  9. DNA radio-induced tandem lesions: formation, introduction in oligonucleotides and repair

    Bourdat, Anne-Gaelle

    2000-01-01

    Cell killing induced by excited photosensitizers, ionizing radiation or radiomimetic drugs can not be only explained by the formation of single DNA lesions. Thus, multiply damaged sites, are likely to have harmful biological consequences. One example of tandem base damage induced by ".OH radical in X-irradiated aqueous solution of DNA oligomers is N-(2-deoxy-β-D-erythro-pentofuranosyl)-formyl-amine (dβF)/8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo). In order to investigate the biological significance of such a tandem lesion, both 8-oxodGuo and dβF were introduced in synthetic oligonucleotides at vicinal positions using the solid phase phosphoramidite method with the 'Pac phosphoramidite' chemistry. The purity of the synthetic DNA fragments and the integrity of modified nucleosides was confirmed using different complementary techniques: HPLC, PAGE, ESI MS, MALDI-TOF MS and capillary electrophoresis. Using the above synthetic substrates, investigations were carried out in order to determine the substrate specificity and the excision mechanism of three glycosylases involved in the base excision repair pathway: endonuclease III, Fpg and yOggl. Both tandem lesions were substrates for the BER enzymes. However, the tandem lesion are not completely excised by the repair enzymes. The rates of excision as inferred from the determination of the ratios of Vm/Km Michaelis kinetics constants were not found to be significantly affected by the presence of the tandem lesions. MALDI-TOF mass spectrometry was used in order to gain insights into mechanistic aspects of oligonucleotide cleavage by the BER enzymes. During in vitro DNA synthesis by Taq DNA polymerase, Klenow fragment exo- and DNA polymerase β, tandem base damage were found to block the progression of the enzymes. Finally, the level of tandem base damage in the DNA exposed to γ-ray using the liquid chromatography coupled to electro-spray ionization tandem mass spectrometry was determined. Both dβF-8-oxodGuo and 8

  10. Simulation of forward dark current voltage characteristics of tandem solar cells

    Rubinelli, F.A.

    2012-01-01

    The transport mechanisms tailoring the shape of dark current–voltage characteristics of amorphous and microcrystalline silicon based tandem solar cell structures are explored with numerical simulations. Our input parameters were calibrated by fitting experimental current voltage curves of single and double junction structures measured under dark and illuminated conditions. At low and intermediate forward voltages the dark current–voltage characteristics show one or two regions with a current–voltage exponential dependence. The diode factor is unique in tandem cells with the same material in both intrinsic layers and two dissimilar diode factors are observed in tandem cells with different materials on the top and bottom intrinsic layers. In the exponential regions the current is controlled by recombination through gap states and by free carrier diffusion. At high forward voltages the current grows more slowly with the applied voltage. The current is influenced by the onset of electron space charge limited current (SCLC) in tandem cells where both intrinsic layers are of amorphous silicon and by series resistance of the bottom cell in tandem cells where both intrinsic layers are of microcrystalline silicon. In the micromorph cell the onset of SCLC becomes visible on the amorphous top sub-cell. The dark current also depends on the thermal generation of electron–hole (e–h) pairs present at the tunneling recombination junction. The highest dependence is observed in the tandem structure where both intrinsic layers are of microcrystalline silicon. The prediction of meaningless dark currents at low forward and reverse voltages by our code is discussed and one solution is given. - Highlights: ► Transport mechanisms shaping the dark current-voltage curves of tandem devices. ► The devices are amorphous and microcrystalline based tandem solar cells. ► Two regions with a current-voltage exponential dependence are observed. ► The tandem J-V diode factor is the

  11. Silicon nanocrystals embedded in silicon carbide for tandem solar cell applications

    Schnabel, Manuel

    2015-01-01

    Tandem solar cells consist of multiple individual solar cells stacked in order of increasing bandgap, with the cell with highest bandgap towards the incident light. This allows photons to be absorbed in the cell that will convert them to electricity with the greatest efficiency, and is the only solar cell concept to surpass the theoretical efficiency limit of a conventional solar cell so far. This work is concerned with the development of silicon nanocrystals (Si NCs) embedded in silicon carbide, which are expected to have a higher bandgap than bulk Si due to quantum confinement, for use in the top cell of a two-junction tandem cell. Charge carrier transport and recombination were investigated as a function of various parameters. Distortion of luminescence spectra by optical interference was highlighted and a robust model to describe transport of majority carriers was developed. Furthermore, a range of processing steps required to produce a Si NC-based tandem cell were studied, culminating in the preparation of the first Si NC-based tandem cells. The resulting cells exhibited open-circuit voltages of 900 mV, demonstrating tandem cell functionality.

  12. Hybrid tandem quantum dot/organic photovoltaic cells with complementary near infrared absorption

    Kim, Taesoo

    2017-06-01

    Monolithically integrated hybrid tandem solar cells that effectively combine solution-processed colloidal quantum dot (CQD) and organic bulk heterojunction subcells to achieve tandem performance that surpasses the individual subcell efficiencies have not been demonstrated to date. In this work, we demonstrate hybrid tandem cells with a low bandgap PbS CQD subcell harvesting the visible and near-infrared photons and a polymer:fullerene—poly (diketopyrrolopyrrole-terthiophene) (PDPP3T):[6,6]-phenyl-C60-butyric acid methyl ester (PC61BM)—top cell absorbing effectively the red and near-infrared photons of the solar spectrum in a complementary fashion. The two subcells are connected in series via an interconnecting layer (ICL) composed of a metal oxide layer, a conjugated polyelectrolyte, and an ultrathin layer of Au. The ultrathin layer of Au forms nano-islands in the ICL, reducing the series resistance, increasing the shunt resistance, and enhancing the device fill-factor. The hybrid tandems reach a power conversion efficiency (PCE) of 7.9%, significantly higher than the PCE of the corresponding individual single cells, representing one of the highest efficiencies reported to date for hybrid tandem solar cells based on CQD and polymer subcells.

  13. On the Relativistic Correction of Particles Trajectory in Tandem Type Electrostatic Accelerator

    Minárik, Stanislav

    2015-08-01

    A constant potential is applied to the acceleration of the ion-beam in the tandem type electrostatic accelerator. However, not just one voltage is applied, but instead a number of applications can be made in succession by means of the tandem arrangement of high voltage tubes. This number of voltage applications, which is the number of so-called "stages" of a tandem accelerator, may be two, three, or four, depending on the chosen design. Electrostatic field with approximately constant intensity acts on ions in any stage. In general, non-relativistic dynamics is used for the description of the ion transport in tandem accelerator. Energies of accelerated ions are too low and relativistic effects cannot be commonly observed by standard experimental technique. Estimation of possible relativistic correction of ion trajectories is therefore only a matter of calculation. In this note, we briefly present such calculation. Our aim is to show how using the relativistic dynamics modifies the particles trajectory in tandem type accelerator and what parameters determine this modification.

  14. Stacking multiple connecting functional materials in tandem organic light-emitting diodes

    Zhang, Tao; Wang, Deng-Ke; Jiang, Nan; Lu, Zheng-Hong

    2017-02-01

    Tandem device is an important architecture in fabricating high performance organic light-emitting diodes and organic photovoltaic cells. The key element in making a high performance tandem device is the connecting materials stack, which plays an important role in electric field distribution, charge generation and charge injection. For a tandem organic light-emitting diode (OLED) with a simple Liq/Al/MoO3 stack, we discovered that there is a significant current lateral spreading causing light emission over an extremely large area outside the OLED pixel when the Al thickness exceeds 2 nm. This spread light emission, caused by an inductive electric field over one of the device unit, limits one’s ability to fabricate high performance tandem devices. To resolve this issue, a new connecting materials stack with a C60 fullerene buffer layer is reported. This new structure permits optimization of the Al metal layer in the connecting stack and thus enables us to fabricate an efficient tandem OLED having a high 155.6 cd/A current efficiency and a low roll-off (or droop) in current efficiency.

  15. The ''Kinetic Stabilizer'': A Simpler Tandem Mirror Confinement?

    Post, R.F.

    2000-01-01

    ion beams are injected along the field lines in such a way as to be reflected before they reach the mirrors, thus forming a localized peak in the plasma density. It will be shown that the power required to produce these stabilizing plasmas is much less than the power per meter of fusion power systems that might employ this technique. Use of the Kinetic Stabilizer idea may therefore permit the construction of tandem mirror fusion power systems that are much smaller and simpler than those based on the use of non-axisymmetric fields to achieve MHD stability

  16. Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

    Li, Guijun, E-mail: gliad@connect.ust.hk; Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing [State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2014-06-09

    Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400–800 nm) and bottom (800–1100 nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

  17. Construction and operational experience of the Tandem Mirror Experiment-Upgrade (TMX-U)

    Chargin, A.K.; Calderon, M.O.; Moore, T.L.

    1983-01-01

    The Tandem Mirror Experiment-Upgrade (TMX-U) incorporates two new features at Lawrence Livermore National Laboratory (LLNL) tandem mirror program, thermal barriers in the end plugs and injection of the neutral beams at several oblique angles. The thermal barriers isolate the electrons in the end plugs from those in the central cell, making it possible to heat them independently with microwaves. In addition, this innovation produces a large potential gradient in the end plugs with lower magnetic fields and lower neutral-beam energies than would be possible in a conventional tandem mirror device. The TMX-U is also designed to test neutral-beam-injection angles as an experimental parameter. We use angles other than 90 0 to produce a plasma with improved microstability

  18. Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

    Li, Guijun; Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing

    2014-01-01

    Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400–800 nm) and bottom (800–1100 nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

  19. Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

    Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

    2018-02-01

    We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density-voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

  20. Tandem white organic light-emitting diodes adopting a C60:rubrene charge generation layer

    Bi Wen-Tao; Wu Xiao-Ming; Hua Yu-Lin; Sun Jin-E; Xiao Zhi-Hui; Wang Li; Yin Shou-Gen

    2014-01-01

    Organic bulk heterojunction fullerence (C 60 ) doped 5, 6, 11, 12-tetraphenylnaphthacene (rubrene) as the high quality charge generation layer (CGL) with high transparency and superior charge generating capability for tandem organic light emitting diodes (OLEDs) is developed. This CGL shows excellent optical transparency about 90%, which can reduce the optical interference effect formed in tandem OLEDs. There is a stable white light emission including 468 nm and 500 nm peaks from the blue emitting layer and 620 nm peak from the red emitting layer in tandem white OLEDs. A high efficiency of about 17.4 cd/A and CIE coordinates of (0.40, 0.35) at 100 cd/m 2 and (0.36, 0.34) at 1000 cd/m 2 have been demonstrated by employing the developed CGL, respectively. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. Transport of dc and bunched beams through a 25 MV folded tandem accelerator

    Milner, W.T.; Alton, G.D.; Hensley, D.C.; Jones, C.M.; King, R.F.; Larson, J.D.; Moak, C.D.; Sayer, R.O.

    1975-01-01

    Studies of beam transport through the planned ORNL 25 MV folded tandem accelerator demonstrate efficient utilization of phase-space acceptance and the feasibility of injecting bunched beams from the tandem accelerator into the Oak Ridge Isochronous Cyclotron (ORIC). Use of a 180 0 bending magnet in the terminal provides outstanding charge state selection and permits better control of the high-energy beam transport than has previously been possible in conventional tandem accelerators. Time spreads introduced in bunched beams by the 180 0 magnet are kept within a 6 0 RF acceptance window at ORIC provided the beam has a crossover in the center of the 180 0 magnet. Ion masses from 12 to 240 amu, preinjection energies from 150 to 500 keV and terminal voltages from 7.5 to 25 MV were studied for dc beams and beams bunched by various modulation techniques. (U.S.)

  2. Probing Photocurrent Nonuniformities in the Subcells of Monolithic Perovskite/Silicon Tandem Solar Cells

    Song, Zhaoning

    2016-11-23

    Perovskite/silicon tandem solar cells with high power conversion efficiencies have the potential to become a commercially viable photovoltaic option in the near future. However, device design and optimization is challenging because conventional characterization methods do not give clear feedback on the localized chemical and physical factors that limit performance within individual subcells, especially when stability and degradation is a concern. In this study, we use light beam induced current (LBIC) to probe photocurrent collection nonuniformities in the individual subcells of perovskite/silicon tandems. The choices of lasers and light biasing conditions allow efficiency-limiting effects relating to processing defects, optical interference within the individual cells, and the evolution of water-induced device degradation to be spatially resolved. The results reveal several types of microscopic defects and demonstrate that eliminating these and managing the optical properties within the multilayer structures will be important for future optimization of perovskite/silicon tandem solar cells.

  3. Plasma Desorption Mass Spectrometry using TANDEM accelerator in National Industrial Research Inst. of Nagoya

    Mizota, Takeshi; Nakao, Setsuo; Niwa, Hiroaki; Saito, Kazuo [Particle Beam Sceince Laboratory, Multi-Function Material Science Department, National Industrial Research Inst. of Nagoya, Nagoya (Japan)

    2001-02-01

    Plasma Desorption Mass Spectrometry (PDMS) analysis was studied using TANDEM accelerator. The heavy ions of MeV range emit the secondary ions of atoms, molecules, polymers and clusters from the irradiated samples without destruction. The analysis system of PDMS designed and set-up using a mass spectrometer of Time of Flight and the TANDEM accelerator. The system performance was tested for C-60 fullerene on the surface of the samples using 11.2 MeV {sup 28}Si beams produced by the TANDEM accelerator of 1.7MV. The result shows that the hydrogen and hydrocarbons can be analyzed in the range of 1amu unit. The resolution (M/{delta}M) of the Mass Spectrometry system is confirmed to be about 1000 from the separation of the 720 and 721amu peaks, which is attributed to the C-60 fullerene including {sup 13}C atoms. (H. Katsuta)

  4. Beam transfer lines for the Tandem-superconducting cyclotron at Lab. Nazionale del Sud

    Calabretta, L.; Cuttone, G.; DiBernardo, P.; Giove, D.; Raia, G.; Yan, C.; Cao, L.; Liu, K.

    1988-01-01

    At the L.N.S. an MP-Tandem will be used as injector for the Superconducting Cyclotron. This paper describes the handling beam system for the Superconducting Cyclotron. All the lines are designed to be achromatic. Home made beam profile monitor is the main diagnostic device and its design and preliminary tests are presented. The distributed computer control for all the beam lines and bunching system is described too. The status of beam transfer line from tandem to S.C. and of bunching system is presented

  5. Robust Tension Control of Strip for 5-Stand Tandem Cold Mills

    Behrooz Shafiei

    2014-01-01

    Full Text Available Tandem cold rolling process is a nonlinear complex system with external and internal uncertainties and significant disturbances. The improvement in the quality of the final output depends on the control strategy of centerline thickness and interstand tension. This paper focuses on interstand tension control problem in 5-stand tandem cold rolling mills. Tension dynamics can be described by a nominal model perturbed by parametric uncertainties. In order to overcome the model uncertainties and external disturbances, suboptimal H∞ and μ controllers are proposed and the Hankel-norm approximation is used to reduce the order of μ controller. The performance of the proposed controllers is demonstrated by some simulations.

  6. Authentication of Fish Products by Large-Scale Comparison of Tandem Mass Spectra

    Wulff, Tune; Nielsen, Michael Engelbrecht; Deelder, André M.

    2013-01-01

    Authentication of food is a major concern worldwide to ensure that food products are correctly labeled in terms of which animals are actually processed for consumption. Normally authentication is based on species recognition by comparison of selected sequences of DNA or protein. We here present...... a new robust, proteome-wide tandem mass spectrometry method for species recognition and food product authentication. The method does not use or require any genome sequences or selection of tandem mass spectra but uses all acquired data. The experimental steps were performed in a simple, standardized...

  7. Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry

    Bornø, Andreas; Foged, Lene; van Hall, Gerrit

    2014-01-01

    The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments...... of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14 days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose...

  8. Improved voltage performance of the Oak Ridge 25URC tandem accelerator

    Meigs, M.J.; Jones, C.M.; Haynes, D.L.; Juras, R.C.; Ziegler, N.F.; Roatz, J.E.; Rathmell, R.D.

    1989-01-01

    This paper reports on the Oak Ridge 25URC tandem electrostatic accelerator one of two accelerators operated by the Holifield Heavy Ion Research Facility (HHIRF) at the Oak Ridge National Laboratory. Placed into routine service in 1982, the accelerator has provided a wide range of heavy ion beams for research in nuclear and atomic physics. These beams have been provided both directly and after further acceleration by the Oak Ridge Isochronous Cyclotron (ORIC). Show schematically in this paper, the tandem accelerator is a model 25URC Pelletron accelerator

  9. Vivitron - A 35 MV Van de Graaff tandem. Design, performance, charge transport system

    Letournel, M.; Helleboid, J.M.; Bertein, H.

    1985-01-01

    This paper describes a new configuration for an electrostatic tandem accelerator. The project of the Strasbourg Nuclear Center is a 35 MV Van de Graaff tandem, in fact a new design in that field. The general features of the machine and its associated electrostatic field are described. The machine is designed to minimise energy dissipation within the accelerator column in the event of electrical breakdown. This is discussed as also insulator and conductor designs. Charge transport system is a particular field. The choice of a belt system and its design result from specific studies carried out at the C.R.N. with reference to the electrostatics of solid and gaseous insulations [fr

  10. Materials Science Division HVEM-Tandem Facility at Argonne National Laboratory

    Taylor, A.

    1981-10-01

    The ANL-Materials Science Division High Voltage Electron Microscope-Tandem Facility is a unique national research facility available to scientists from industry, universities, and other national laboratories, following a peer evaluation of their research proposals by the Facility Steering Committee. The principal equipment consists of a Kratos EM7 1.2-MV high voltage electron microscope, a 300-kV Texas Nuclear ion accelerator, and a National Electrostatics 2-MV Tandem accelerator. Ions from both accelerators are transmitted into the electron microscope through the ion-beam interface. Recent work at the facility is summarized

  11. SEBIM pilot operated tandems. A new solution for Darlington NGS bleed condenser relief valves

    Paetzold, H.; Hera, V.; Schaumburg, G.

    1996-01-01

    Following incidents at Pickering, Wolsung and Bruce NGS, involving instability of bleed condenser relief valves, Darlington station decided to replace the spring loaded RV's by new pilot operated SEBIM tandem valves. This paper is presenting the approach taken, the design and the testing of the new solution, as well as some of the computer modeling work performed in connection with this project. The SEBIM tandems, following successful testing in France, will be installed in Darlington Unit 2, this spring. The new valves can perform with absence of instability and prevent a LOCA incident due to their design, which includes a protection and a redundant valve in series. (author)

  12. Preparation of ethylene/1-hexene copolymers from ethylene using a fully silica-supported tandem catalyst system

    Karbach, Fabian F.; Macko, Tibor; Duchateau, Robbert

    2016-01-01

    A silica-supported tandem catalyst system, capable of producing ethylene/1-hexene copolymers from ethylene being the single monomer, has been investigated. As tandem couple a phenoxyimine titanium catalyst for ethylene trimerization was combined with a metallocene catalyst for α-olefin

  13. GENETIC DIVERSITY OF TYPHA LATIFOLIA (TYPHACEAE) AND THE IMPACT OF POLLUTANTS EXAMINED WITH TANDEM-REPETITIVE DNA PROBES

    Genetic diversity at variable-number-tandem-repeat (VNTR) loci was examined in the common cattail, Typha latifolia (Typhaceae), using three synthetic DNA probes composed of tandemly repeated "core" sequences (GACA, GATA, and GCAC). The principal objectives of this investigation w...

  14. Crystalline silicon solar cell with front and rear polysilicon passivated contacts as bottom cell for hybrid tandems

    Luxembourg, S.L.; Zhang, D.; Wu, Y.; Najafi, M.; Zardetto, V.; Verhees, W.; Burgers, A.R.; Veenstra, S.; Geerligs, L.J.

    2017-01-01

    In this paper we analyze and model perovskite/c-Si tandem cells with front and rear polySi passivated contacts on the bottom cell. A high-efficiency tandem approach will benefit from the high Voc potential of a c-Si bottom cell with front and rear polySi passivated contacts while the combination

  15. Zinc tin oxide as high-temperature stable recombination layer for mesoscopic perovskite/silicon monolithic tandem solar cells

    Werner, Jérémie

    2016-12-05

    Perovskite/crystalline silicon tandem solar cells have the potential to reach efficiencies beyond those of silicon single-junction record devices. However, the high-temperature process of 500 °C needed for state-of-the-art mesoscopic perovskite cells has, so far, been limiting their implementation in monolithic tandem devices. Here, we demonstrate the applicability of zinc tin oxide as a recombination layer and show its electrical and optical stability at temperatures up to 500 °C. To prove the concept, we fabricate monolithic tandem cells with mesoscopic top cell with up to 16% efficiency. We then investigate the effect of zinc tin oxide layer thickness variation, showing a strong influence on the optical interference pattern within the tandem device. Finally, we discuss the perspective of mesoscopic perovskite cells for high-efficiency monolithic tandem solar cells. © 2016 Author(s)

  16. Designing and overproducing a tandem epitope of gp350/220 that shows a potential to become an EBV vaccine

    Widodo

    2018-03-01

    Full Text Available Background: Epstein-Barr virus (EBV can cause cancer in people from around the world. There is no EBV vaccine available for use on a global scale. However, emerging evidence suggests that the epitope on the gp350/220 capsid protein may be developed into an EBV vaccine. Nevertheless, the production of small, single epitope is challenging of stability issues and possible alteration of peptide structure. In this study, a tandem epitope was developed consisting of three single epitopes, aimed to improve stability, antigenicity and preserve epitope structure. Materials and methods: A tandem epitope was designed using bioinformatics based on the epitope structure of the gp350/220 protein. The tandem epitope structure was analyzed using a protein folding method with Abalone software, which was further refined via YASARA force field and molecular repairing using a FoldX method. Immunogenicity was examined with Epitopia software, whereas allergen properties were tested using AlgPred. The pattern of the tandem epitope binding with anti-gp350/220 antibodies was performed using Z-dock and snugDock. The tandem epitope was then overproduced in E. coli strain BL21 as a host cell. Result: Our model demonstrated a successfully designed and overproduced tandem epitope. The tandem epitope demonstrated a similar structure compared with the epitope of whole protein gp350/220. Our epitope also demonstrated non-allergen and antigenicity properties, and possessed antibody binding patterns consistent with whole protein gp350/220. Conclusion and recommendation: These data suggest a novel tandem epitope composed of three similar epitopes demonstrates antigenicity, structure, and binding properties consistent with whole protein gp350/220. We also demonstrate successful production of the tandem epitope using E. coli strain BL21 as a host. Future in vivo experimental animal research is necessary to test the ability of this tandem epitope to stimulate antibody production

  17. Monte Carlo particle simulation and finite-element techniques for tandem mirror transport

    Rognlien, T.D.; Cohen, B.I.; Matsuda, Y.; Stewart, J.J. Jr.

    1987-01-01

    A description is given of numerical methods used in the study of axial transport in tandem mirrors owing to Coulomb collisions and rf diffusion. The methods are Monte Carlo particle simulations and direct solution to the Fokker-Planck equations by finite-element expansion. (author)

  18. Present status of tandem accelerator analysis facility in National Institute for Environmental Studies

    Kume, Hiroshi; Shibata, Yasuyuki; Tanaka, Atsushi; Yoneda, Minoru; Kumamoto, Yuichiro; Uehiro, Takashi; Morita, Masatoshi [National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan)

    1996-12-01

    In National Institute for Environmental Studies, two types of tandem accelerator analysis facilities were able to be installed in September, 1995. One is the accelerator mass analysis exclusive equipment with a 5 MV tandem accelerator, and the other is the high energy ion beam analyzer, in which the surface analysis system is connected to a 1 MV tandem accelerator, mainly used for PIXE measurement. The accelerator mass analyzer can be roughly divided into four parts, that is, ion source and negative ion injection system, accelerator, high energy analysis system, minute amount isotope beam line and control system. These parts are briefly explained. The test measurement of carbon isotope ratio was carried out, but the results dispersed and unsatisfactory. As for the ion beam analyzer, the surface analysis system (RBS400) of Charles Evans and Associates is combined with a 1 MV PELETRON tandem accelerator (3SDH) of NEC, and these are described. This analyzer also is not in the state that the steady operation can be carried out. Slight leak occurred in the ion source. The countermeasures to both cases are in progress. (K.I.)

  19. Present status of tandem accelerator in Japan Atomic Energy Research Institute

    Yoshida, Tadashi; Kanda, Susumu; Takeuchi, Suehiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-12-01

    The tandem accelerator in Japan Atomic Energy Research Institute was made by NEC in USA. Since it is the accelerator of turning-up structure, it has large magnet at the high voltage terminal, and supplies electric power by driving a generator with large diameter shaft. The control is carried out by CAMUCK, and the electronic circuit is protected from the surging arising due to discharge. Since the experiment on full scale was begun, 14 years have elapsed, and at present, it became a very stable accelerator. As to the operation mode, the acceleration voltage is limited to below 17 MV. The operation voltage and the state of operation are shown. Recently, the troubles of chains originating in oil have occurred. The adjustment of the tandem accelerator requires more than one month. The adjustment is mainly related to the chains and shafts, and this is explained. The ion source used for the tandem accelerator at present is the negative ion source made by NEC. The installation of an ECR ion source is planned. The utilization of the tandem accelerator system is reported. (K.I.)

  20. Toward Male Individualization with Rapidly Mutating Y-Chromosomal Short Tandem Repeats

    K. Ballantyne (Kaye); A. Ralf (Arwin); R. Aboukhalid (Rachid); N.M. Achakzai (Niaz); T. Anjos (Tania); Q. Ayub (Qasim); J. Balažic (Jože); J. Ballantyne (Jack); D.J. Ballard (David); B. Berger (Burkhard); C. Bobillo (Cecilia); M. Bouabdellah (Mehdi); H. Burri (Helen); T. Capal (Tomas); S. Caratti (Stefano); J. Cárdenas (Jorge); F. Cartault (François); E.F. Carvalho (Elizeu); M. de Carvalho (Margarete); B. Cheng (Baowen); M.D. Coble (Michael); D. Comas (David); D. Corach (Daniel); M. D'Amato (Mauro); S. Davison (Sean); P. de Knijff (Peter); M.C.A. de Ungria (Maria Corazon); R. Decorte (Ronny); T. Dobosz (Tadeusz); B.M. Dupuy (Berit); S. Elmrghni (Samir); M. Gliwiński (Mateusz); S.C. Gomes (Sara); L. Grol (Laurens); C. Haas (Cordula); E. Hanson (Erin); J. Henke (Jürgen); L. Henke (Lotte); F. Herrera-Rodríguez (Fabiola); C.R. Hill (Carolyn); G. Holmlund (Gunilla); K. Honda (Katsuya); U.-D. Immel (Uta-Dorothee); S. Inokuchi (Shota); R. Jobling; M. Kaddura (Mahmoud); J.S. Kim (Jong); S.H. Kim (Soon); W. Kim (Wook); T.E. King (Turi); E. Klausriegler (Eva); D. Kling (Daniel); L. Kovačević (Lejla); L. Kovatsi (Leda); P. Krajewski (Paweł); S. Kravchenko (Sergey); M.H.D. Larmuseau (Maarten); E.Y. Lee (Eun Young); R. Lessig (Rüdiger); L.A. Livshits (Ludmila); D. Marjanović (Damir); M. Minarik (Marek); N. Mizuno (Natsuko); H. Moreira (Helena); N. Morling (Niels); M. Mukherjee (Meeta); P. Munier (Patrick); J. Nagaraju (Javaregowda); F. Neuhuber (Franz); S. Nie (Shengjie); P. Nilasitsataporn (Premlaphat); T. Nishi (Takeki); H.H. Oh (Hye); S. Olofsson (Sylvia); V. Onofri (Valerio); J. Palo (Jukka); H. Pamjav (Horolma); W. Parson (Walther); M. Petlach (Michal); C. Phillips (Christopher); R. Ploski (Rafal); S.P.R. Prasad (Samayamantri P.); D. Primorac (Dragan); G.A. Purnomo (Gludhug); J. Purps (Josephine); H. Rangel-Villalobos (Hector); K. Reogonekbała (Krzysztof); B. Rerkamnuaychoke (Budsaba); D.R. Gonzalez (Danel Rey); C. Robino (Carlo); L. Roewer (Lutz); A. de Rosa (Anna); A. Sajantila (Antti); A. Sala (Andrea); J.M. Salvador (Jazelyn); P. Sanz (Paula); C. Schmitt (Christian); A.K. Sharma (Anisha K.); D.A. Silva (Dayse); K.-J. Shin (Kyoung-Jin); T. Sijen (Titia); M. Sirker (Miriam); D. Siváková (Daniela); V. Škaro (Vedrana); C. Solano-Matamoros (Carlos); L. Souto (L.); V. Stenzl (Vlastimil); H. Sudoyo (Herawati); D. Syndercombe-Court (Denise); A. Tagliabracci (Adriano); D. Taylor (Duncan); A. Tillmar (Andreas); I.S. Tsybovsky (Iosif); C. Tyler-Smith (Chris); K. van der Gaag (Kristiaan); D. Vanek (Daniel); A. Völgyi (Antónia); D. Ward (Denise); P. Willemse (Patricia); E.P.H. Yap (Eric); Z-Y. Yong (Ze-Yie); I.Z. Pajnič (Irena Zupanič); M.H. Kayser (Manfred)

    2014-01-01

    textabstractRelevant for various areas of human genetics, Y-chromosomal short tandem repeats (Y-STRs) are commonly used for testing close paternal relationships among individuals and populations, and for male lineage identification. However, even the widely used 17-loci Yfiler set cannot resolve

  1. Importance Sampling Simulation of Population Overflow in Two-node Tandem Networks

    Nicola, V.F.; Zaburnenko, T.S.; Baier, C; Chiola, G.; Smirni, E.

    2005-01-01

    In this paper we consider the application of importance sampling in simulations of Markovian tandem networks in order to estimate the probability of rare events, such as network population overflow. We propose a heuristic methodology to obtain a good approximation to the 'optimal' state-dependent

  2. Allele frequencies of ten short tandem repeats loci in the central ...

    2009-04-03

    Apr 3, 2009 ... c Indian Academy of Sciences. RESEARCH NOTE. Allele frequencies of ten short tandem ... Statistical parameters of forensic importance, the power of discrimination (PD), observed and expected ... rameters indicated the usefulness of the loci in forensic per- sonal identification and paternity testing among ...

  3. Language Learning Shifts and Attitudes towards Language Learning in an Online Tandem Program for Beginner Writers

    Tolosa, Constanza; Ordóñez, Claudia Lucía; Guevara, Diana Carolina

    2017-01-01

    We present findings of a project that investigated the potential of an online tandem program to enhance the foreign language learning of two groups of school-aged beginner learners, one learning English in Colombia and the other learning Spanish in New Zealand. We assessed the impact of the project on students' learning with a free writing…

  4. Start up of the Tandem Accelerator in the Ezeiza Atomic Center

    Bianchini, R.; Consorti, S.; Roldan, M.; Llovera, R.; Arenilla, P.; Alvarez, D.E.; Ugarte, R.

    2010-01-01

    A High Voltage tandem electrostatic accelerator FN model was installed and started up by the Nuclear Regulatory Authority (ARN) on the campus of Ezeiza Atomic Center. Subsequently, the facility was transferred to the National Atomic Energy Commission for a new start up, re-engineering, maintenance, and operation [es

  5. JAERI TANDEM, LINAC and V.D.G. annual report 1989

    1990-09-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator, the electron linear accelerator and the Van de Graaff accelerator from April 1, 1989 to March 31, 1990. Summary reports of 49 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  6. Functional Diversity of Tandem Substrate-Binding Domains in ABC Transporters from Pathogenic Bacteria

    Fulyani, Faizah; Schuurman-Wolters, Gea K.; Vujicic - Zagar, Andreja; Guskov, Albert; Slotboom, Dirk-Jan; Poolman, Bert

    2013-01-01

    The ATP-binding cassette (ABC) transporter GInPQ is an essential uptake system for amino acids in gram-positive pathogens and related nonpathogenic bacteria. The transporter has tandem substrate-binding domains (SBDs) fused to each transmembrane domain, giving rise to four SBDs per functional

  7. Variable-number tandem repeats as molecular markers for biotypes of Pasteuria ramosa in Daphnia spp.

    Mouton, Laurence; Nong, Guang; Preston, James F; Ebert, Dieter

    2007-06-01

    Variable-number tandem repeats (VNTRs) have been identified in populations of Pasteuria ramosa, a castrating endobacterium of Daphnia species. The allelic polymorphisms at 14 loci in laboratory and geographically diverse soil samples showed that VNTRs may serve as biomarkers for the genetic characterization of P. ramosa isolates.

  8. Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer.

    Lei, Yu; Lin, Guan-yu

    2013-01-01

    Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution, high spectral resolution, and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror, it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating, which make the anterior Wadsworth condition fulfilling each wavelength, is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband.

  9. Genome-wide analysis of tandem repeats in plants and green algae

    Zhixin Zhao; Cheng Guo; Sreeskandarajan Sutharzan; Pei Li; Craig Echt; Jie Zhang; Chun Liang

    2014-01-01

    Tandem repeats (TRs) extensively exist in the genomes of prokaryotes and eukaryotes. Based on the sequenced genomes and gene annotations of 31 plant and algal species in Phytozome version 8.0 (http://www.phytozome.net/), we examined TRs in a genome-wide scale, characterized their distributions and motif features, and explored their putative biological functions. Among...

  10. Status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostic system

    Coutts, G.W.; Coffield, F.E.; Hornady, R.S.

    1983-01-01

    This paper presents the current status of the Tandem Mirror Experiment-Upgrade (TMX-U) diagnostics system. For the initial instruments active on TMX-U, the expansions or upgrades that have been implemented are outlined. For the newly added systems, more implementation details are presented

  11. Linked tandem mirror configuration as a possible steady state high β plasma container

    Ikuta, Kazunari.

    1982-04-01

    A possibility of achieving steady state high β plasma confinement in toroidal geometry is considered in detail by closing off the ends of tandem mirrors entirely by flux bridges, where β is the ratio of plasma pressure to the magnetic pressure. The key problem of this approach seems to be the magnetic design of magneto-hydrodynamically stabilized, preferentially leaky bridges. (author)

  12. Final version of the pick-up wheels in the Pelletron tandem accelerator at Lund

    Hakansson, K.; Hellborg, R.

    1993-01-01

    A new type of pick-up wheel has been designed and constructed for the charge transport system of the Lund 3UDH Pelletron tandem accelerator. The major improvements compared with older types are a slender design with only one ball bearing and more robust contact pins with a rubber ring between the pinhead and the wheel nave. (orig.)

  13. X-Chromosomal short tandem repeat loci in the Turkish population ...

    In this study, we aimed to demonstrate the importance and utility of polymorphic short tandem repeat (STR) found on the human X chromosome and to provide the first allelic frequency data of X-STR (X chromosomal) loci in the Turkish population. Blood samples were taken from unrelated individuals (135 males and 129 ...

  14. Cytokinin profiling in plant tissues using ultra-performance liquid chromatography–electrospray tandem mass spectrometry

    Novák, Ondřej; Hauserová, Eva; Amakorová, Petra; Doležal, Karel; Strnad, Miroslav

    2008-01-01

    Roč. 69, č. 11 (2008), s. 2214-2224 ISSN 0031-9422 R&D Projects: GA AV ČR KAN200380801 Institutional research plan: CEZ:AV0Z50380511 Keywords : Ultra-performance liquid chromatography (UPLC) * Tandem mass spectrometry (MS/MS) * Microextraction Subject RIV: EC - Immunology Impact factor: 2.946, year: 2008

  15. RUTHENIUM-CATALYZED TANDEM OLEFIN MIGRATION-ALDOL AND MANNICH-TYPE REACTIONS IN IONIC LIQUID.

    In the presence of a catalytic amount of RuCl2(PPh3)3, a cross-coupling of 3-buten-2-ol with aldehydes and imines was developed via a tandem olefin migration--aldol--Mannich reaction in bmim[PF6]. With In(OAc)3 as a co-catalyst, a-vinylbenzyl alcohol and aldehydes underwent sim...

  16. Materials science symposium 'heavy ion science in tandem energy region'

    Iwamoto, Akira; Yoshida, Tadashi; Takeuchi, Suehiro [eds.

    2000-01-01

    The tandem accelerator established at Japan Atomic Energy Research Institute (JAERI) in 1982 has been one of the most prominent electrostatic accelerators in the world. The accelerator has been serving for many researches planned by not only JAERI staff but also researchers of universities and national institutes. After the completion of the tandem booster in 1993, four times higher beam energy became available. These two facilities, the tandem accelerator and the booster, made great strides in heavy ion physics and a lot of achievements have been accumulated until now. The research departments of JAERI were reformed in 1998, and the accelerators section came under the Department of Materials Science. On this reform of the research system, the symposium 'Heavy Ion Science in Tandem Energy Region' was held in cooperation with nuclear and solid state physicists although there has been no such symposium for many years. The symposium was expected to stimulate novel development in both nuclear and solid state physics, and also interdisciplinary physics between nuclear and solid state physics. The 68 papers are indexed individually. (J.P.N.)

  17. JAERI tandem and V.D.G. annual report 1998. April 1, 1998 - March 31, 1999

    NONE

    1999-12-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 1998 to March 31, 1999. Summary reports of 38 papers, and lists of publication, personnel and cooperative research with universities and contained. (author)

  18. Electron and ion cyclotron heating calculations in the tandem-mirror modeling code MERTH

    Smith, G.R.

    1985-01-01

    To better understand and predict tandem-mirror experiments, we are building a comprehensive Mirror Equilibrium Radial Transport and Heating (MERTH) code. In this paper we first describe our method for developing the code. Then we report our plans for the installation of physics packages for electron- and ion-cyclotron heating of the plasma

  19. Tandem radical reactions and ring-closing metathesis. Application in the synthesis of cyclooctenes.

    Sibi, Mukund P; Aasmul, Mona; Hasegawa, Hikaru; Subramanian, Thangaiah

    2003-08-07

    [reaction: see text] Fumarate- and acrylate-substituted oxazolidinones undergo tandem radical reaction to form dienes in moderate to good yields. The resulting dienes provide cyclooctenes in moderate to good yields after ring-closing metathesis (RCM). The role of the carbon backbone substituents and other variables in the efficiency of the eight-membered ring formation is discussed.

  20. High work function transparent middle electrode for organic tandem solar cells

    Moet, D. J. D.; de Bruyn, P.; Blom, P. W. M.

    2010-01-01

    The use of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) in combination with ZnO as middle electrode in solution-processed organic tandem solar cells requires a pH modification of the PEDOT:PSS dispersion. We demonstrate that this neutralization leads to a reduced work function

  1. JAERI tandem annual report 2002. April 1, 2002 - March 31, 2003

    Takeuchi, Suehiro; Oshima, Masumi; Ishii, Tetsuro; Nagame, Yuichiro; Chiba, Satoshi; Sataka, Masao

    2003-11-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 2002 to March 31, 2003. Summary reports of 54 papers, and lists of publication, personnel and cooperative research with universities are contained. (author)

  2. JAERI tandem and V.D.G. annual report 1997. April 1, 1997 - March 31, 1998

    Takeuchi, Suehiro; Ikezoe, Hiroshi; Chiba, Satoshi; Sataka, Masao; Nagame, Yuichiro; Takemori, Satoshi; Iwamoto, Akira

    1998-10-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 1997 to March 31, 1998. Summary reports of 40 papers, and lists of publication, personnel and cooperative researches with universities are contained. (author)

  3. JAERI TANDEM and V.D.G. annual report 1992 April 1, 1992 - March 31, 1993

    1993-09-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 1992 to March 31, 1993. Summary reports of 41 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  4. JAERI tandem, linac and V.D.G. annual report 1984

    Shikazono, Naomoto; Iizumi, Masashi; Ishii, Mitsuhiko; Kawarasaki, Yuuki; Murayama, Michio; Okashita, Hiroshi; Ozawa, Kunio; Suto, Yoichi

    1985-07-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator, the electron linear accelerator and the Van de Graaff accelerator from April 1, 1984 to March 31, 1985. Summary reports of 53 papers, publications, personnel and a list of cooperative researches with universities are contained. (author)

  5. JAERI tandem, linac and V.D.G. annual report 1987

    1988-10-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator, the electron linear accelerator and the Van de Graaff accelerator from April 1, 1987 to March 31, 1988. Summary reports of 49 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  6. JAERI TANDEM and V.D.G. annual report 1994. April 1, 1994 - March 31, 1995

    Suzuki, Yasuo; Ikezoe, Hiroshi; Iwamoto, Akira; Sataka, Masao; Shinohara, Nobuo; Takeuchi, Suehiro; Shoji, Tokio; Okabe, Takashi

    1995-10-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 1994 to March 31, 1995. Summary reports of 47 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  7. Very high frequency plasma deposited amorphous/nanocrystalline silicon tandem solar cells on flexible substrates

    Liu, Y.|info:eu-repo/dai/nl/304831743

    2010-01-01

    The work in this thesis is to develop high quality intrinsic layers (especially nc-Si:H) for micromorph silicon tandem solar cells/modules on plastic substrates following the substrate transfer method or knows as the Helianthos procedure. Two objectives are covered in this thesis: (1) preliminary

  8. Organic-inorganic halide perovskites: perspectives for silicon-based tandem solar cells

    Löper, P.; Niesen, B.; Moon, S.J.; Martin de Nicolas, S.; Holovský, Jakub; Remeš, Zdeněk; Ledinský, Martin; Haug, F.J.; Yum, J. H.; De Wolf, S.; Ballif, C.

    2014-01-01

    Roč. 4, č. 6 (2014), s. 1545-1551 ISSN 2156-3381 R&D Projects: GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : perovskite * tandem solar cells * optical absorption * photothermal deflection spectroscopy * degradation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.165, year: 2014

  9. Tandem shock waves in medicine and biology: a review of potential applications and successes

    Lukeš, Petr; Fernández, F.; Gutiérrez-Aceves, J.; Fernández, E.; Alvarez, U.M.; Šunka, Pavel; Loske, A.M.

    2016-01-01

    Roč. 26, č. 1 (2016), s. 1-23 ISSN 0938-1287 Institutional support: RVO:61389021 Keywords : Tandem shock waves * Acoustic cavitation * Clinical applications * Bactericidal effect * Genetic transformation * Cancer treatment Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.107, year: 2016 http://link.springer.com/article/10.1007%2Fs00193-015-0577-0

  10. Sequence-specific DNA alkylation by tandem Py-Im polyamide conjugates.

    Taylor, Rhys Dylan; Kawamoto, Yusuke; Hashiya, Kaori; Bando, Toshikazu; Sugiyama, Hiroshi

    2014-09-01

    Tandem N-methylpyrrole-N-methylimidazole (Py-Im) polyamides with good sequence-specific DNA-alkylating activities have been designed and synthesized. Three alkylating tandem Py-Im polyamides with different linkers, which each contained the same moiety for the recognition of a 10 bp DNA sequence, were evaluated for their reactivity and selectivity by DNA alkylation, using high-resolution denaturing gel electrophoresis. All three conjugates displayed high reactivities for the target sequence. In particular, polyamide 1, which contained a β-alanine linker, displayed the most-selective sequence-specific alkylation towards the target 10 bp DNA sequence. The tandem Py-Im polyamide conjugates displayed greater sequence-specific DNA alkylation than conventional hairpin Py-Im polyamide conjugates (4 and 5). For further research, the design of tandem Py-Im polyamide conjugates could play an important role in targeting specific gene sequences. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. JAERI tandem annual report 2001. April 1, 2001 - March 31, 2002

    Takeuchi, Suehiro; Ikezoe, Hiroshi; Chiba, Satoshi; Nagame, Yuichiro; Sataka, Masao; Iwamoto, Akira (eds.) [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-11-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 2001 to March 31, 2002. Summary reports of 48 papers, and lists of publication, personnel and cooperative research with universities are contained. (author)

  12. Tandemly repeated sequence in 5'end of mtDNA control region of ...

    Extensive length variability was observed in 5' end sequence of the mitochondrial DNA control region of the Japanese Spanish mackerel (Scomberomorus niphonius). This length variability was due to the presence of varying numbers of a 56-bp tandemly repeated sequence and a 46-bp insertion/deletion (indel).

  13. GPU accelerated tandem traversal of blocked bounding volume hierarchy collision detection for multibody dynamics

    Damkjær, Jesper; Erleben, Kenny

    2009-01-01

    and a simultaneous descend in the tandem traversal. The data structure design and traversal are highly specialized for exploiting the parallel threads in the NVIDIA GPUs. As proof-of-concept we demonstrate a GPU implementation for a multibody dynamics simulation, showing an approximate speedup factor of up to 8...

  14. JAERI TANDEM annual report 2000. April 1, 2000 - March 31, 2001

    Takeuchi, Suehiro; Ikezoe, Hiroshi; Chiba, Satoshi; Nagame, Yuichiro; Sataka, Masao; Iwamoto, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] (eds.)

    2001-11-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 2000 to March 31, 2001. Summary reports of 46 papers, and lists of publication, personnel and cooperative research with universities are contained. (author)

  15. Tandem Mannich/Diels–Alder reactions for the synthesis of indole compound libraries

    Wu, Peng; Petersen, Michael Åxman; Petersen, Rico

    2016-01-01

    A tandem Mannich/Diels–Alder sequence for the synthesis of small-molecule libraries with an indolyl-octahydro-3a,6-epoxy-isoindole core structure is demonstrated in this study. Representative diversification examples based on this scaffold were performed, and a library is being produced within...

  16. Note on an energy scanning system for a Van de Graaff or a tandem accelerator

    Camplan, J.

    1987-01-01

    In a system including one electrostatic deflector, one magnet and a second electrostatic deflector used for energy scanning of particles outgoing from a tandem or a Van de Graaff accelerator, we derive equations linking positions and deflexions of the two deflectors. (orig.)

  17. The modification of the terminal electrostatic field of HI-13 tandem accelerator

    Li Tao; Guan Xialing

    1993-01-01

    The calculation of electrostatic field of terminal and its neighbour region for HI-13 tandem accelerator is made. The limit terminal voltage without tubes is evaluated. Using elliptical cross section in stead of circular ones for the first six equipotential rings, the electrostatic field of this region are modified

  18. Simple and efficient importance sampling scheme for a tandem queue with server slow-down

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2008-01-01

    This paper considers importance sampling as a tool for rare-event simulation. The system at hand is a so-called tandem queue with slow-down, which essentially means that the server of the first queue (or: upstream queue) switches to a lower speed when the second queue (downstream queue) exceeds some

  19. JAERI TANDEM and V.D.G. annual report 1995. April 1, 1995 - March 31, 1996

    Takeuchi, Suehiro; Ikezoe, Hiroshi; Iwamoto, Akira; Sataka, Masao; Nagame, Yuichiro; Shoji, Tokio; Okabe, Takashi; Maekawa, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; eds.

    1996-08-01

    This annual report describes research activities which have been performed with the JAERI Tandem accelerator and the Van de Graaff accelerator from April 1, 1995 to March 31, 1996. Summary reports of 59 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  20. A review of recent progress in heterogeneous silicon tandem solar cells

    Yamaguchi, Masafumi; Lee, Kan-Hua; Araki, Kenji; Kojima, Nobuaki

    2018-04-01

    Silicon solar cells are the most established solar cell technology and are expected to dominate the market in the near future. As state-of-the-art silicon solar cells are approaching the Shockley-Queisser limit, stacking silicon solar cells with other photovoltaic materials to form multi-junction devices is an obvious pathway to further raise the efficiency. However, many challenges stand in the way of fully realizing the potential of silicon tandem solar cells because heterogeneously integrating silicon with other materials often degrades their qualities. Recently, above or near 30% silicon tandem solar cell has been demonstrated, showing the promise of achieving high-efficiency and low-cost solar cells via silicon tandem. This paper reviews the recent progress of integrating solar cell with other mainstream solar cell materials. The first part of this review focuses on the integration of silicon with III-V semiconductor solar cells, which is a long-researched topic since the emergence of III-V semiconductors. We will describe the main approaches—heteroepitaxy, wafer bonding and mechanical stacking—as well as other novel approaches. The second part introduces the integration of silicon with polycrystalline thin-film solar cells, mainly perovskites on silicon solar cells because of its rapid progress recently. We will also use an analytical model to compare the material qualities of different types of silicon tandem solar cells and project their practical efficiency limits.

  1. Heat-pipe liquid-pool-blanket concept for the Tandem Mirror Reactor

    Hoffman, M.A.; Werner, R.W.; Johnson, G.L.

    1981-01-01

    The blanket concept for the tandem mirror reactor described in this paper was developed to produce the medium temperature heat (approx. 850 to 950 K) for the General Atomic sulfur-iodine thermochemical process for producing hydrogen. This medium temperature heat from the blanket constitutes about 81% of the total power output of the fusion reactor

  2. Tandem-pulsed acousto-optics: an analytical framework of modulated high-contrast speckle patterns

    Resink, Steffen; Steenbergen, Wiendelt

    2015-01-01

    Recently we presented acousto-optic (AO) probing of scattering media using addition or subtraction of speckle patterns due to tandem nanosecond pulses. Here we present a theoretical framework for ideal (polarized, noise-free) speckle patterns with unity contrast that links ultrasound-induced optical

  3. Learner Perspectives on Task Design for Oral-Visual eTandem Language Learning

    El-Hariri, Yasmin

    2016-01-01

    Constituting a more specific form of online collaboration, eTandem Language Learning (eTLL) shows great potential for non-formal, self-directed language learning. Research in this field, particularly regarding task design, is still scarce. Focusing on their beliefs and attitudes, this article examines what learners think about how…

  4. JAERI tandem and V.D.G. annual report 1993. April 1, 1993 - March 31, 1994

    Suzuki, Yasuo; Ikezoe, Hiroshi; Iwamoto, Akira; Kazumata, Yukio; Shinohara, Nobuo; Takeuchi, Suehiro; Okabe, Takashi

    1994-11-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 1993 to March 31, 1994. Summary reports of 43 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  5. Tandem ring-closing metathesis/isomerization reactions for the total synthesis of violacein

    Petersen, Mette Terp; Nielsen, Thomas Eiland

    2013-01-01

    A series of 5-substituted 2-pyrrolidinones was synthesized through a one-pot ruthenium alkylidene-catalyzed tandem RCM/isomerization/nucleophilic addition sequence. The intermediates resulting from RCM/isomerization showed reactivity toward electrophiles in aldol condensation reactions which...

  6. A spectral theory approach for extreme value analysis in a tandem of fluid queues

    J.W. Bosman (Joost); R. Núñez Queija (Rudesindo)

    2014-01-01

    htmlabstractWe consider a model to evaluate performance of streaming media over an unreliable network. Our model consists of a tandem of two fluid queues. The first fluid queue is a Markov modulated fluid queue that models the network congestion, and the second queue represents the play-out buffer.

  7. Interchange stability criteria for anisotropic central-cell plasmas in the tandem mirror GAMMA 10

    Hojo, Hitoshi; Inutake, Masaaki; Ichimura, Makoto; Katsumata, Ryota; Watanabe, Tsuguhiro.

    1993-05-01

    Flute interchange stability of anisotropic central-cell plasmas in the tandem mirror GAMMA 10 is studied numerically. The stability criteria on the beta value is obtained as a function of axial localization length of the pressure in both central and anchor cells. The temperature anisotropy of the plasma is also discussed. (author)

  8. A proposal for study of ion-beam induced chemical reactions using JAERI tandem accelerator

    1985-11-01

    Problems in ion-beam induced chemical reactions using JAERI Tandem Accelerator were discussed. Research philosophy, some proposed experiments which are based on measurements during ion-beam bombardment, and main features of the experimental apparatus are briefly described in this report. (author)

  9. Design for the magnetic field requirements of the tandem mirror experiment

    Chen, F.K.; Chargin, A.K.; Denhoy, B.S.; Waugh, A.F.

    1977-01-01

    The tandem mirror magnetic geometry is described, followed by an analysis of the magnet set designed to meet the requirements of the TMX experiment. The final magnet line-up is composed of a baseball coil with two C coils for each plug, six solenoidal coils for the central cell, and two RC coils plus one octupole coil for each transition

  10. Self-similarity of far wake behind tandem of two disks

    Okulov, Valery; Litvinov, I. V.; Naumov, I. V.

    2017-01-01

    the wake ceased to differ from the background of natural turbulent fluctuations of the incident flow. It has been found that the position of the second disk in the tandem affects the energy loss in the wake due to its expansion but does not influence the decay. The revealed patterns in the wake development...

  11. Synthesis of 2-vinylic indoles and derivatives via a Pd-catalyzed tandem coupling reaction.

    Fayol, Aude; Fang, Yuan-Qing; Lautens, Mark

    2006-09-14

    A novel one-step synthesis of valuable 2-vinylic indoles and their tricycle derivatives is described. This reaction, which utilizes a gem-dibromovinyl unit as a readily available starting material, occurs via an efficient Pd-catalyzed tandem Buchwald-Hartwig/Heck reaction.

  12. JAERI Tandem, LINAC and V.D.G. annual report 1986

    1987-08-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator, the electron linear accelerator and the Van de Graaff accelerator from April 1, 1986 to March 31, 1987. Summary reports of 55 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  13. Argonne National Laboratory 1980-1981 tandem-linac accelerator report

    Hartog, P.D.; Pardo, R.; Munson, F.; Heath, C.

    1981-01-01

    Performance of the facility is discussed. The FN tandem Van de Graaff is now used as an injector for the superconducting linac; heavy-ion beams are being injected. Stripper foil development is described, with fabrication by arc evaporation and by RF discharge compared. Facility modifications, such as the control room, are discussed

  14. Proceedings of the 13th meeting for tandem accelerators and related techniques

    NONE

    2001-02-01

    The 13th Meeting for Tandem Accelerators and Related Techniques was held on June 8-9, 2000 at Mutsu, Aomori Prefecture, under the auspices of Marine Research Laboratory, Mutsu Establishment, the Japan Atomic Energy Research Institute. About 60 people participated in the meeting from 27 universities and organizations, many of which have a tandem accelerator or an electrostatic accelerator. The objectives of the meeting are to exchange information on tandem accelerates or electrostatic accelerators by making a presentation on related research and topics, and also to enhance mutual friendship of participants, resulting in the contribution to associated R and D. The meeting mainly consisted of presentations by participants and corresponding Q and A; the present situation on facilities of accelerator mass spectrometers (AMS), operations of and research on tandem accelerators or electrostatic accelerators, applications of AMS, related techniques and applications using accelerators, and so on. This report summarizes the contents of presentations made in the meeting. The 30 of the presented papers are indexed individually. (J.P.N.)

  15. Controller routines for the DECsystem-10 with application to a tandem-mirror plasma code

    Faul, D.R.; Devoto, R.S.

    1979-01-01

    FORTRAN-callable subroutines have been written to enable controller--controllee interaction on the LLL DECsystem-10. These subroutines have been used to construct a controller (XTCTMR) for a tandem-mirror physics code (CTCTMR). A description of the subroutines and their use is presented. Also, sample results are given

  16. Spectral properties of the tandem Jackson network, seen as a quasi-birth-and-death process

    Kroese, D.P.; Scheinhardt, W.R.W.; Taylor, P.G.

    2004-01-01

    Quasi-birth-and-death (QBD) processes with infinite “phase spaces" can exhibit unusual and interesting behavior. One of the simplest examples of such a process is the two-node tandem Jackson network, with the “phase" giving the state of the first queue and the “level" giving the state of the second

  17. JAERI tandem annual report 1999. April 1, 1999 - March 31, 2000

    NONE

    2000-11-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 1999 to March 31, 2000. Summary reports of 49 papers, and lists of publication, personnel and cooperative research with universities are contained. (author)

  18. Investigation of InGaN/Si double junction tandem solar cells | Bouzid ...

    In this work, the solar power conversion efficiency of InGaN/Si double junction tandem solar cells was investigated under 1-sun AM1.5 illumination, using realistic material parameters. With this intention, the current-voltage curves are calculated for different front recombination velocities and the influence of the bottom cell ...

  19. Enhanced antibody-dependent cellular phagocytosis by chimeric monoclonal antibodies with tandemly repeated Fc domains.

    Nagashima, Hiroaki; Ootsubo, Michiko; Fukazawa, Mizuki; Motoi, Sotaro; Konakahara, Shu; Masuho, Yasuhiko

    2011-04-01

    We previously reported that chimeric monoclonal antibodies (mAbs) with tandemly repeated Fc domains, which were developed by introducing tandem repeats of Fc domains downstream of 2 Fab domains, augmented binding avidities for all Fcγ receptors, resulting in enhanced antibody (Ab)-dependent cellular cytotoxicity. Here we investigated regarding Ab-dependent cellular phagocytosis (ADCP) mediated by these chimeric mAbs, which is considered one of the most important mechanisms that kills tumor cells, using two-color flow cytometric methods. ADCP mediated by T3-Ab, a chimeric mAb with 3 tandemly repeated Fc domains, was 5 times more potent than that by native anti-CD20 M-Ab (M-Ab hereafter). Furthermore, T3-Ab-mediated ADCP was resistant to competitive inhibition by intravenous Ig (IVIG), although M-Ab-mediated ADCP decreased in the presence of IVIG. An Fcγ receptor-blocking study demonstrated that T3-Ab mediated ADCP via both FcγRIA and FcγRIIA, whereas M-Ab mediated ADCP exclusively via FcγRIA. These results suggest that chimeric mAbs with tandemly repeated Fc domains enhance ADCP as well as ADCC, and that Fc multimerization may significantly enhance the efficacy of therapeutic Abs. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  20. Liquid chromatographic-tandem mass spectrometric determination of selected sulphonamides in milk

    Rhijn, van J.A.; Lasaroms, J.J.P.; Berendsen, B.J.A.; Brinkman, U.A.Th.

    2002-01-01

    Liquid chromatography–tandem mass spectrometry is used for the quantitative analysis of selected sulphonamides in milk. Ultrafiltration is the only sample pre-treatment technique which is required. Consequently, sample throughput is much higher than with conventional procedures, and analyte

  1. Highly efficient tandem polymer solar cells with a photovoltaic response in the visible light range.

    Zheng, Zhong; Zhang, Shaoqing; Zhang, Maojie; Zhao, Kang; Ye, Long; Chen, Yu; Yang, Bei; Hou, Jianhui

    2015-02-18

    Highly efficient polymer solar cells with a tandem structure are fabricated by using two excellent photovoltaic polymers and a highly transparent intermediate recombination layer. Power conversion -efficiencies over 10% can be realized with a photovoltaic response within 800 nm. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Hybrid tandem solar cells with depleted-heterojunction quantum dot and polymer bulk heterojunction subcells

    Kim, Taesoo; Gao, Yangqin; Hu, Hanlin; Yan, Buyi; Ning, Zhijun; Jagadamma, Lethy Krishnan; Zhao, Kui; Kirmani, Ahmad R.; Eid, Jessica; Adachi, Michael M.; Sargent, Edward H.; Beaujuge, Pierre; Amassian, Aram

    2015-01-01

    with underlayers and associated constraints on the tandem architecture, and show that an adequate device configuration consists of a low bandgap CQD bottom cell and a high bandgap polymer:fullerene top cell. Once we optimize the recombination layer and individual

  3. JAERI tandem, LINAC and V.D.G. annual report 1988

    1989-09-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator, the electron linear accelerator and the Van de Graaff accelerator from April 1, 1988 to March 31, 1989. Summary reports of 45 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  4. A novel tandem Betti/Ullmann oxidation reaction as an efficient route ...

    Betti reaction; cross-coupling reaction; oxidation; heterogeneous catalysis. Abstract. A novel tandem Betti/Ullmann/oxidation reaction was used for synthesis of new oxazepine derivatives containing kojic acid. This protocol ... This method provides a new and useful strategy for the construction of heterocycles. Also novel Betti ...

  5. JAERI TANDEM, LINAC and V.D.G. annual report, 1985

    1986-08-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator, the electron linear accelerator and the Van de Graaff accelerator from April 1, 1985 to March 31, 1986. Summary reports of 52 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  6. JAERI TANDEM and V.D.G. annual report 1996. April 1, 1996 - March 31, 1997

    Takeuchi, Suehiro; Ikezoe, Hiroshi; Iwamoto, Akira; Sataka, Masao; Nagame, Yuichiro; Shoji, Tokio; Okabe, Takashi; Maekawa, Hiroshi

    1997-09-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaf accelerator from April 1, 1996 to March 31, 1997. Summary reports of 48 papers, and list of publications, personnel and cooperative researches with universities are contained. (author)

  7. JAERI TANDEM and V.D.G. annual report 1994. April 1, 1994 - March 31, 1995

    Suzuki, Yasuo; Ikezoe, Hiroshi; Iwamoto, Akira; Sataka, Masao; Shinohara, Nobuo; Takeuchi, Suehiro; Shoji, Tokio; Okabe, Takashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; eds.

    1995-10-01

    This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 1994 to March 31, 1995. Summary reports of 47 papers, and list of publications, personnel and cooperative researches with universities are contained. (author).

  8. Measuring the external quantum efficiency of two-terminal polymer tandem solar cells

    Gilot, J.; Wienk, M.M.; Janssen, R.A.J.

    2010-01-01

    Tandem configurations, in which two cells are stacked and connected in series, offer a viable approach to further increase the power conversion efficiency (PCE) of organic solar cells. To enable the future rational design of new materials it is important to accurately assess the contributions of

  9. Simulation of a Jackson tandem network using state-dependent importance sampling

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2008-01-01

    This paper considers importance sampling as a tool for rare-event simulation. The focus is on estimating the probability of overflow in the downstream queue of a Jackson two-node tandem queue. It is known that in this setting 'traditional' state-independent importance-sampling distributions perform

  10. Model for ion confinement in a hot-electron tandem mirror anchor

    Baldwin, D.E.

    1980-01-01

    Anisotropic, hot electrons trapped in local minimum-B wells have been proposed as MHD-stabilizing anchors to an otherwise axisymmetric tandem configuration. This work describes a model for plasma confinement between the anchors and the remainder of the system and calcuates the power loss implied by maintenance of this plasma

  11. Monte Carlo particle simulation and finite-element techniques for tandem mirror transport

    Rognlien, T.D.; Cohen, B.I.; Matsuda, Y.; Stewart, J.J. Jr.

    1985-12-01

    A description is given of numerical methods used in the study of axial transport in tandem mirrors owing to Coulomb collisions and rf diffusion. The methods are Monte Carlo particle simulations and direct solution to the Fokker-Planck equations by finite-element expansion. 11 refs

  12. Delay in a tandem queueing model with mobile queues: An analytical approximation

    Al Hanbali, Ahmad; de Haan, Roland; Boucherie, Richardus J.; van Ommeren, Jan C.W.

    In this paper, we analyze the end-to-end delay performance of a tandem queueing system with mobile queues. Due to state-space explosion, there is no hope for a numerical exact analysis for the joint-queue-length distribution. For this reason, we present an analytical approximation that is based on

  13. Combined heat and power plants with parallel tandem steam turbines; Smaaskalig kraftvaerme med parallellkopplade tandemturbiner

    Steinwall, Pontus; Norstroem, Urban; Pettersson, Camilla; Oesterlin, Erik

    2004-12-01

    We investigate the technical and economical conditions for a concept with parallel coupled tandem turbines in small scale combined heat and power plants fired with bio-fuel and waste. Performance and heat production costs at varying electricity prices for the concept with two smaller tandem coupled steam turbines has been compared to the traditional concept with one single multi-staged turbine. Three different types of plants have been investigated: - Bio fuelled CHP plant with thermal capacity of 15 MW{sub th}; - Waste fired CHP plant with thermal capacity of 20 MW{sub th}; - Bio fuelled CHP plant with thermal capacity of 25 MW{sub th}. The simple steam turbines (Curtis turbines) used in the tandem arrangement has an isentropic efficiency of about 49 to 53% compared to the multi-staged steam turbines with isentropic efficiency in the range of 59% to 81%. The lower isentropic efficiency for the single staged turbines is to some extent compensated at partial load when one of the two turbines can be shut down leading to better operational conditions for the one still in operation. For concepts with saturated steam at partial load below 50% the tandem arrangements presents higher electricity efficiency than the conventional single turbine alternative. The difference in annual production of electricity is therefore less than the difference in isentropic efficiency for the two concepts. Production of electricity is between 2% and 42% lower for the tandem arrangements in this study. Investment costs for the turbine island has been calculated for the two turbine concepts and when the costs for turbines, generator, power transmission, condensing system, piping system, buildings, assembling, commissioning and engineering has been added the sum is about the same for the two concepts. For the bio-fuelled plant with thermal capacity of 15 MW{sub th} the turbine island amount to about 10-12 MSEK and about 13-15 MSEK for the waste fired plant with a thermal capacity of 20 MW

  14. Randomized Trial of Oral Misoprostol Treatment for Cervical Ripening Before Tandem Application in Cervix Cancer

    Cepni, Kimia; Gul, Sule; Cepni, Ismail; Gueralp, Onur; Sal, Veysel; Mayadagli, Alpaslan

    2011-01-01

    Purpose: To investigate the efficacy of oral misoprostol administered to facilitate tandem application to the cervix as a part of brachytherapy in patients with cervical cancer. Methods and Materials: Eighty patients with cervical cancer who had been planned to undergo brachytherapy at Dr. Luetfi Kirdar Kartal Training and Research Hospital were evaluated in a double-blind, prospective, randomized trial. Patients were divided randomly into two groups of 40 patients. The first and second groups received 400 μg of misoprostol orally and placebo, respectively, 3 h before tandem application. The two groups were compared in terms of age, diameter of tumor, parity, age at first intercourse, amount of bleeding and pain at first tandem application, length of endometrial cavity measured by hysterometer, and size of Hegar dilators used for cervical dilatation. Results: Of all cases, 63.6%, 16.3%, 10%, 6.3%, 2.5%, and 1.3% were Stage IIB, IIIB, IIIA, IVA, IIA and IIC, respectively. Mean (±SD) age (range) was 49.3 ± 13.1 (25-83) years and 56.6 ± 13.2 (30-78) years in the study and control groups, respectively (p = 0.015). Age at first intercourse, diameter of tumor, parity, amount of bleeding at first tandem application, and length of endometrial cavity measured by hysterometer were not significantly different between the two groups. Pain score was significantly higher in the control group (p < 0.001). Application was significantly easier in the study group compared with controls (p < 0.001). Average size of initial Hegar dilators used for cervical dilatation was significantly higher in the study group compared with controls (p = 0.017). Conclusion: Administration of misoprostol 400 μg orally for cervical ripening before tandem application facilitates the procedure, increases patient tolerability and comfort, and may decrease complication rates.

  15. Impact of 'optimized' treatment planning for tandem and ring, and tandem and ovoids, using high dose rate brachytherapy for cervical cancer

    Noyes, William R.; Peters, Nancy E.; Thomadsen, Bruce R.; Fowler, Jack F.; Buchler, Dolores A.; Stitt, Judith A.; Kinsella, Timothy J.

    1995-01-01

    Purpose: Different treatment techniques are used in high dose rate (HDR) remote afterloading intracavitary brachytherapy for uterine cervical cancer. We have investigated the differences between 'optimized' and 'nonoptimized' therapy using both a tandem and ring (T/R) applicator, and a tandem and ovoids (T/O), applicator. Methods and Materials: HDR afterloading brachytherapy using the Madison System for Stage IB cervical cancer was simulated for 10 different patients using both a T/R applicator and a T/O applicator. A treatment course consists of external beam irradiation and five insertions of HDR afterloading brachytherapy. Full dosimetry calculations were performed at the initial insertion for both applicators and used as a reference for the following four insertions of the appropriate applicator. Forty dosimetry calculations were performed to determine the dose delivered to Point M (similar to Point A), Point E (obturator lymph nodes), vaginal surface, bladder, and rectum. 'Optimized' doses were specified to Point M and to the vaginal surface. 'Nonoptimized' doses were specified to Point M only. Using the linear-quadratic equation, calculations have been performed to convert the delivered dose using HDR to the biologically equivalent doses at the conventional low dose rate (LDR) at 0.60 Gy/h. Results: Major differences between 'optimized' and 'nonoptimized' LDR equivalent doses were found at the vaginal surface, bladder, and rectum. Overdoses at the vaginal surface, bladder, and rectum were calculated to be 208%, nil, and 42%, respectively, for the T/R applicator with 'nonoptimization'. However, for the T/O applicator, the overdoses were smaller, being nil, 32%, and 27%, respectively, with 'nonoptimization'. Conclusion: Doses given in high dose rate intracavitary brachytherapy border on tissue tolerance. 'Optimization' of either applicator decreases the risk of a dose that may have potential for complications. Optimization of a tandem and ovoids best ensures

  16. Annual report of Department of Research Reactors and Tandem Accelerator, JFY2006. Operation, utilization and technical development of JRR-3, JRR-4, NSRR and Tandem Accelerator

    2007-12-01

    The Department of Research Reactors and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor-3), JRR-4 (Japan Research Reactor-4) and NSRR (Nuclear Safety Research Reactor) and Tandem Accelerator. The following services and technical developments were achieved in Japanese Fiscal Year 2006: 1) JRR-3 was operated for 181 days in 7 cycles and JRR-4 for 149 days in 37 cycles to provide neutrons for research and development of in-house and outside users. 2) JRR-3 and JRR-4 were utilized through deliberate coordination as follows, a) Neutron irradiations of 628 materials, for neutron transmutation doping of silicon etc. b) Capsule irradiations of 3,067 samples, for neutron activation analyses etc. c) Neutron beam experiments of 6,338 cases x days. 3) Concerning to the 10 times increasing plan of cold neutron beams from JRR-3, a pressure resistant test model of the high-performance neutron moderator vessel which had been designed to increase cold neutrons twice as much as the present one was fabricated. Various developments for upgrading cold neutron guide tubes with super mirrors were in progress. 4) Boron neutron capture therapy was carried out 34 times using JRR-4. Improved neutron collimators were built to fit well to any irregular outline for cancer around the neck. 5) NSRR carried out 4 times of pulse irradiations of high burn-up MOX fuels and 9 times of un-irradiated fuels to contribute to fuel safety researches. 6) The Tandem Accelerator was operated for 201 days to contribute to the researches of nuclear physics and solid state physics with high energy heavy ions. The new utilization program of sharing beam times with outside users was performed by carrying out 45 days. The beam intensity increasing program with a high performance ion source, in place of the compact one which has been working in the high voltage terminal, has made great progress. (author)

  17. SU-F-T-633: Cyberknife Boost Versus Conventional Tandem and Ovoid Treatment for Cervical Cancer

    Santoro, J; Witten, M; Haas, J [Winthrop University Hospital, Lynbrook, NY (United States)

    2016-06-15

    Purpose: Brachytherapy has been the standard of care for cervical cancer for 100 years. The treatment can be administered using an HDR (high dose rate) remote afterloader with a {sup 192}Ir source in an outpatient setting, a PDR afterloader with a {sup 192}Ir source, or with LDR manually loaded or a remote afterloader utilizing {sup 192}Ir or {sup 137}Cs sources in an inpatient setting. The procedure involves the placement of a tandem and ovoid, tandem and ring, or tandem and cylinder applicator in an operating room setting with the patient under general anesthesia. Inaccuracies introduced into the process occurring between placement of the applicator and actual delivery can introduce uncertainty into the actual dose delivered to the tumor and critical organs. In this study we seek to investigate the dosimetric difference between an SBRT-based radiotherapy boost and conventional Brachytherapy in treating cervical cancer. Methods: Five HDR tandem and ovoid patients were planned using the Brachyvision treatment planning system and treated in four fractions using the Varian Varisource afterloader (Varian Medical Systems). For the same cohort, the patient planning CTs were imported into Multiplan (Accuray Inc) and a dose/fractionation-equivalent CyberKnife SBRT plan was retrospectively generated. Dosimetric quantities such as target/CTV D90, V90, D2cc for rectum, bladder, and bowel were measured and compared between the two modalities. Results: The CTV D90 for the tandem and ovoid was 2540cGy (90.7%) and 3009cGy (107.5%) for the CyberKnife plan. The D2cc for the rectum, bladder, and bowel were 1576cGy, 1641cGy, and 996cGy for the tandem and ovoid and 1374cGy, 1564cGy, and 1547cGy for CyberKnife. Conclusion: The D2cc doses to critical structures are comparable in both modalities. The CTV coverage is far superior for the CyberKnife plan. The dose distribution for CyberKnife has the advantage of increased conformality and lower maximum CTV dose.

  18. Homo-Tandem Polymer Solar Cells withVOC>1.8 V for Efficient PV-Driven Water Splitting

    Gao, Yangqin; Le Corre, Vincent M.; Gaï tis, Alexandre; Neophytou, Marios; Hamid, Mahmoud Abdul; Takanabe, Kazuhiro; Beaujuge, Pierre

    2016-01-01

    Efficient homo-tandem and triple-junction polymer solar cells are constructed by stacking identical subcells composed of the wide-bandgap polymer PBDTTPD, achieving power conversion efficiencies >8% paralleled by open-circuit voltages >1.8 V

  19. Hybrid Tandem Quantum Dot/Organic Solar Cells with Enhanced Photocurrent and Efficiency via Ink and Interlayer Engineering

    Kim, Taesoo; Firdaus, Yuliar; Kirmani, Ahmad R.; Liang, Ru-Ze; Hu, Hanlin; Liu, Mengxia; El Labban, Abdulrahman; Hoogland, Sjoerd; Beaujuge, Pierre; Sargent, Edward H.; Amassian, Aram

    2018-01-01

    Realization of colloidal quantum dot (CQD)/organic photovoltaic (OPV) tandem solar cells that integrate the strong infrared absorption of CQDs with large photovoltages of OPVs is an attractive option toward high-performing, low-cost thin film solar

  20. Field Performance versus Standard Test Condition Efficiency of Tandem Solar Cells and the Specific Case of Perovskites/Silicon Devices

    Dupre, Olivier; Niesen, Bjö rn; De Wolf, Stefaan; Ballif, Christophe

    2018-01-01

    efficiencies and calculate their energy yields using field data from Denver. We find that annual losses due to differences between operating conditions and standard test conditions are similar for single-junction and four-terminal tandem devices. The additional