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Sample records for accelerating factor cd55

  1. Decay accelerating factor (CD55 protects neuronal cells from chemical hypoxia-induced injury

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    Tsokos George C

    2010-04-01

    Full Text Available Abstract Background Activated complement system is known to mediate neuroinflammation and neurodegeneration following exposure to hypoxic-ischemic insults. Therefore, inhibition of the complement activation cascade may represent a potential therapeutic strategy for the management of ischemic brain injury. Decay-accelerating factor (DAF, also known as CD55 inhibits complement activation by suppressing the function of C3/C5 convertases, thereby limiting local generation or deposition of C3a/C5a and membrane attack complex (MAC or C5b-9 production. The present study investigates the ability of DAF to protect primary cultured neuronal cells subjected to sodium cyanide (NaCN-induced hypoxia from degeneration and apoptosis. Methods Cultured primary cortical neurons from embryonic Sprague-Dawley rats were assigned one of four groups: control, DAF treatment alone, hypoxic, or hypoxic treated with DAF. Hypoxic cultures were exposed to NaCN for 1 hour, rinsed, followed by 24 hour exposure to 200 ng/ml of recombinant human DAF in normal medium. Human DAF was used in the present study and it has been shown to effectively regulate complement activation in rats. Neuronal cell function, morphology and viability were investigated by measuring plateau depolarization potential, counting the number dendritic spines, and observing TUNEL and MTT assays. Complement C3, C3a, C3a receptor (R production, C3a-C3aR interaction and MAC formation were assessed along with the generation of activated caspase-9, activated caspase-3, and activated Src. Results When compared to controls, hypoxic cells had fewer dendritic spines, reduced plateau depolarization accompanied by increased apoptotic activity and accumulation of MAC, as well as up-regulation of C3, C3a and C3aR, enhancement of C3a-C3aR engagement, and elevated caspase and Src activity. Treatment of hypoxic cells with 200 ng/ml of recombinant human DAF resulted in attenuation of neuronal apoptosis and exerted

  2. The Expression and Action of Decay-Accelerating Factor (CD55 in Human Malignancies and Cancer Therapy

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    Jan-Henrik Mikesch

    2006-01-01

    Full Text Available Decay-accelerating factor (DAF, CD55 is physiologically acting as an inhibitor of the complement system, but is also broadly expressed in malignant tumours. Here DAF seems to exert different functions beyond its immunological role such as e.g. promotion of tumorigenesis, decrease of complement mediated tumor cell lysis, autocrine loops for cell rescue and evasion of apoptosis, neoangiogenesis, invasiveness, cell motility, and metastasis via oncogenic tyrosine kinase pathways and specific seven-span transmembrane receptors (CD97 binding. Therefore, DAF has already become a target for therapy. In this paper we review the role of DAF in human malignancies as described in different basic, diagnostic and experimental therapeutic studies.

  3. The effects of prednisone and steroid-sparing agents on decay accelerating factor (CD55) expression: implications in myasthenia gravis.

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    Auret, Jennifer; Abrahams, Amaal; Prince, Sharon; Heckmann, Jeannine M

    2014-06-01

    Decay accelerating factor (DAF) expression at the muscle endplate is an important defence against complement-mediated damage in myasthenia gravis. Previously we implicated the c.-198C>G DAF polymorphism with the development of treatment-resistant myasthenia-associated ophthalmoplegia by showing that the C>G DAF polymorphism prevented lipopolysaccharide-induced upregulation of lymphoblast DAF. We postulated that drugs used in myasthenia gravis may increase the susceptibility of extraocular muscles to complement-mediated damage and studied their effects on endogenous DAF using patient-derived lymphoblasts as well as mouse myotubes. We show that prednisone repressed C>G DAF expression in lymphoblasts and increased their susceptibility to cytotoxicity. Methotrexate, but not azathioprine or cyclosporine, increased DAF in C>G lymphoblasts. In mouse myotubes expressing wild-type Daf, prednisone also repressed Daf expression. Although cyclosporine, azathioprine, and methotrexate increased muscle Daf levels when used alone, upon co-treatment with prednisone only azathioprine maintained myotube Daf levels close to basal. Therefore, prednisone negatively influences DAF expression in C>G lymphoblasts and in myotubes expressing wild-type Daf. We speculate that myasthenic individuals at risk of developing the ophthalmoplegic complication, such as those with C>G DAF, may have inadequate endogenous levels of complement regulatory protein protection in their extraocular muscle in response to prednisone, increasing their susceptibility to complement-mediated damage.

  4. Piracy of decay-accelerating factor (CD55) signal transduction by the diffusely adhering strain Escherichia coli C1845 promotes cytoskeletal F-actin rearrangements in cultured human intestinal INT407 cells.

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    Peiffer, I; Servin, A L; Bernet-Camard, M F

    1998-09-01

    Diffusely adhering Escherichia coli (DAEC) C1845 (clinical isolate) harboring the fimbrial adhesin F1845 can infect cultured human differentiated intestinal epithelial cells; this process is followed by the disassembly of the actin network in the apical domain. The aim of this study was to examine the mechanism by which DAEC C1845 promotes F-actin rearrangements. For this purpose, we used a human embryonic intestinal cell line (INT407) expressing the membrane-associated glycosylphosphatidylinositol (GPI) protein-anchored decay-accelerating factor (DAF), the receptor of the F1845 adhesin. We show here that infection of INT407 cells by DAEC C1845 can provoke dramatic F-actin rearrangements without cell entry. Clustering of phosphotyrosines was observed, revealing that the DAEC C1845-DAF interaction involves the recruitment of signal transduction molecules. A pharmacological approach with a subset of inhibitors of signal transduction molecules was used to identify the cascade of signal transduction molecules that are coupled to the DAF, that are activated upon infection, and that promote the F-actin rearrangements. DAEC C1845-induced F-actin rearrangements can be blocked dose dependently by protein tyrosine kinase, phospholipase Cgamma, phosphatidylinositol 3-kinase, protein kinase C, and Ca2+ inhibitors. F-actin rearrangements and blocking by inhibitors were observed after infection of the cells with two E. coli recombinants carrying the plasmids containing the fimbrial adhesin F1845 or the fimbrial hemagglutinin Dr, belonging to the same family of adhesins. These findings show that the DAEC Dr family of pathogens promotes alterations in the intestinal cell cytoskeleton by piracy of the DAF-GPI signal cascade without bacterial cell entry.

  5. Investigation of several influential factors on flow cytometry analysis of CD55 and CD59 expression on red blood cells%红细胞CD55、CD59流式细胞术检测方法的若干影响因素探讨

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    张薇薇; 张军; 方超平; 沈茜

    2011-01-01

    Objective To study some factors that may influence the measurements of CD55 and CD59 expression on red blood cells by flow cytometry and establish the standard operation procedure. Methods Ethylene diamine tetraacetic acid( EDTA )-anticoagulated peripheral bloods from 15 patients with non-hematological disorder and 11 patients with paroxysmal nocturnal hemoglobinuria ( PNH ) were determined for CD55 and CD59 expression on red blood cells by flow cytometry. The various amounts of monoclonal antibody ( mAb ), the fluorescein type that conjugated with mAb and the staining time were analyzed. Results The mean fluorescence intensity ( MFI ) increased with the increasing amount of mAb before the saturated amount of mAb ( < 9 jjlL ) were added. The positive rates and MFI from using anti-CD55 labeled with fluorescein isothiocyanate ( FITC ) were lower than those from anti-CD55-phycoerythrin ( PE ). There was no statistical significance in CD59 positive rate between FITC and PE, while the higher MFI was observed significantly using anti-CD59-FITC. The staining time had a significant impact on not only the positive rate of CD55-PE but also the MFI obtained from CD59-FITC and CD55-PE ( P <0. 05 ), except the CD59-FITC positive rate between the 2 groups with 3 h. Conclusions The flow cytometry analysis of CD55 and CD59 expression on red blood cells is strongly influenced by the mAb amount, the mAb's fluorescein type and staining time. To ensure a proper reaction and a reliable result, we recommend a two-color staining method of anti-CD59-FITC and anti-CD55-PE, red blood cells in the range from 1.6 X 105 to 2. 8 X 105 stained with 12 jxL of each mAb and an incubation time of 40 min.%目的 探讨流式细胞仪测定红细胞表面CD55、CD59试验过程中影响检测的若干因素,建立此项目的 标准操作程序.方法 利用流式细胞仪对15例非血液病、11例阵发性血红蛋白尿症(PNH)的乙二胺四乙酸(EDTA)外周抗凝血进行红细胞CD55、CD59

  6. Production of multiple transgenic Yucatan miniature pigs expressing human complement regulatory factors, human CD55, CD59, and H-transferase genes.

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    Young-Hee Jeong

    Full Text Available The present study was conducted to generate transgenic pigs coexpressing human CD55, CD59, and H-transferase (HT using an IRES-mediated polycistronic vector. The study focused on hyperacute rejection (HAR when considering clinical xenotransplantation as an alternative source for human organ transplants. In total, 35 transgenic cloned piglets were produced by somatic cell nuclear transfer (SCNT and were confirmed for genomic integration of the transgenes from umbilical cord samples by PCR analysis. Eighteen swine umbilical vein endothelial cells (SUVEC were isolated from umbilical cord veins freshly obtained from the piglets. We observed a higher expression of transgenes in the transgenic SUVEC (Tg SUVEC compared with the human umbilical vein endothelial cells (HUVEC. Among these genes, HT and hCD59 were expressed at a higher level in the tested Tg organs compared with non-Tg control organs, but there was no difference in hCD55 expression between them. The transgenes in various organs of the Tg clones revealed organ-specific and spatial expression patterns. Using from 0 to 50% human serum solutions, we performed human complement-mediated cytolysis assays. The results showed that, overall, the Tg SUVEC tested had greater survival rates than did the non-Tg SUVEC, and the Tg SUVEC with higher HT expression levels tended to have more down-regulated α-Gal epitope expression, resulting in greater protection against cytotoxicity. By contrast, several Tg SUVEC with low CD55 expression exhibited a decreased resistance response to cytolysis. These results indicated that the levels of HT expression were inversely correlated with the levels of α-Gal epitope expression and that the combined expression of hCD55, hCD59, and HT proteins in SUVECs markedly enhances a protective response to human serum-mediated cytolysis. Taken together, these results suggest that combining a polycistronic vector system with SCNT methods provides a fast and efficient alternative

  7. Triggering of the dsRNA sensors TLR3, MDA5, and RIG-I induces CD55 expression in synovial fibroblasts.

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    Olga N Karpus

    Full Text Available BACKGROUND: CD55 (decay-accelerating factor is a complement-regulatory protein highly expressed on fibroblast-like synoviocytes (FLS. CD55 is also a ligand for CD97, an adhesion-type G protein-coupled receptor abundantly present on leukocytes. Little is known regarding the regulation of CD55 expression in FLS. METHODS: FLS isolated from arthritis patients were stimulated with pro-inflammatory cytokines and Toll-like receptor (TLR ligands. Transfection with polyinosinic-polycytidylic acid (poly(I:C and 5'-triphosphate RNA were used to activate the cytoplasmic double-stranded (dsRNA sensors melanoma differentiation-associated gene 5 (MDA5 and retinoic acid-inducible gene-I (RIG-I. CD55 expression, cell viability, and binding of CD97-loaded beads were quantified by flow cytometry. RESULTS: CD55 was expressed at equal levels on FLS isolated from patients with rheumatoid arthritis (RA, osteoarthritis, psoriatic arthritis and spondyloarthritis. CD55 expression in RA FLS was significantly induced by IL-1β and especially by the TLR3 ligand poly(I:C. Activation of MDA5 and RIG-I also enhanced CD55 expression. Notably, activation of MDA5 dose-dependently induced cell death, while triggering of TLR3 or RIG-I had a minor effect on viability. Upregulation of CD55 enhanced the binding capacity of FLS to CD97-loaded beads, which could be blocked by antibodies against CD55. CONCLUSIONS: Activation of dsRNA sensors enhances the expression of CD55 in cultured FLS, which increases the binding to CD97. Our findings suggest that dsRNA promotes the interaction between FLS and CD97-expressing leukocytes.

  8. A functional SNP in the regulatory region of the decay-accelerating factor gene associates with extraocular muscle pareses in myasthenia gravis

    OpenAIRE

    Heckmann, J M; Uwimpuhwe, H; Ballo, R; Kaur, M.; Bajic, V.B.; Prince, S.

    2009-01-01

    Complement activation in myasthenia gravis (MG) may damage muscle endplate and complement regulatory proteins such as decay-accelerating factor (DAF) or CD55 may be protective. We hypothesize that the increased prevalence of severe extraocular muscle (EOM) dysfunction among African MG subjects reported earlier may result from altered DAF expression. To test this hypothesis, we screened the DAF gene sequences relevant to the classical complement pathway and found an association between myasthe...

  9. Expression of membrane complement regulators, CD46, CD55 and CD59, in mesothelial cells of patients on peritoneal dialysis therapy.

    Science.gov (United States)

    Sei, Yumi; Mizuno, Masashi; Suzuki, Yasuhiro; Imai, Masaki; Higashide, Keiko; Harris, Claire L; Sakata, Fumiko; Iguchi, Daiki; Fujiwara, Michitaka; Kodera, Yasuhiro; Maruyama, Shoichi; Matsuo, Seiichi; Ito, Yasuhiko

    2015-06-01

    We investigated the expression of membrane complement regulators (CRegs), CD46, CD55 and CD59 in human mesothelial cells, and correlated with clinical background and level of complement (C) activation products in peritoneal dialysis (PD) fluids (PDF) to clarify influence of the C activation system in PD patients. Expression of CRegs was assessed on primary cultures of mesothelial cells (HPMC) harvested from PD fluid of 31 PD patients. Because expression of CD55 but not CD46 and CD59 in mesothelial cells was significantly correlated to value of dialysate-to-plasma creatinine concentration ratio (D/P Cre) (p<0.005) as an indicator of peritoneal function, we focused on analysis of CD55 expression of HPMCs in comparison with levels of C activation products in the PDF of the PD patients, and their background factors. When comparing expression of the CRegs between systemic neutrophils and HPMC, no correlation was observed, supporting that change of CRegs' expression in HPMC was independently occurring in the peritoneum. Expression of CD55 protein in HPMC was closely correlated with expression at the mRNA level (p<0.0001) and was inversely correlated with levels of sC5b-9 (p<0.05), but not C3, C4, IL6 and CA125 in the PDF. Complications of diabetes, usage of icodextrin and residual renal function were not correlated with change of CD55 expression in HPMCs. Our data show that the process of PD therapy modifies expression of CD55 on peritoneal mesothelium and triggers local C activation. These findings support efforts to modify PD therapy to limit effects on activation and regulation of the C system.

  10. Clinical Significance of the Detection of CD55, CD59 Expression Deletion in Patients with Cytopenia%血细胞减少患者衰变加速因子和膜反应性溶血抑制物表达缺失检测的临床意义

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    吕敏; 朱焕玲; 蒋能刚; 曾婷婷

    2012-01-01

    目的 检测血细胞减少患者外周血红细胞和中性粒细胞细胞膜糖基磷脂酰肌醇(GPI)连接的补体调节蛋白衰变加速因子(CD55)和膜反应性溶血抑制物(CD59)表达情况,并探讨其临床意义.方法 2006年7月-2011年3月,采用直接免疫荧光标记法流式细胞仪检测182例血细胞减少患者外周血CD55及CD59表达情况,其中阵发性睡眠性血红蛋白尿(PNH)9例,再生障碍性贫血(AA) -PNH综合征8例,AA 83例,骨髓增生异常综合征51例,自身免疫性溶血性贫血11例,造血功能停滞6例,缺铁性贫血7例,巨幼细胞性贫血4例,脾功能亢进3例.结果 PNH及AA-PNH患者CD55、CD59抗原缺失率均较其他血细胞减少者明显增高.结论 流式细胞仪检测外周血中红细胞和中性粒细胞膜CD55和CD59抗原表达缺失率是目前诊断PNH可靠和敏感的方法,也是对PNH、AA-PNH早期诊断敏感指标,并且PNH克隆检测还能为诊断疾病提供鉴别诊断依据.%Objective To explore the expression of decaying accelerating factor (CD55) and membrane inhibitor of reactive lysis (CD59) connected with glycosylphosphatidylinositol (GPI) on the membranes of peripheral blood cells and neutrophils in patients with cytopenia, and research on their clinical significance. Methods From July 2006 to March 2011, By directing immunofiuorescence flow cytometry, we detected the expression levels of CD55 and CD59 in 182 patients with cytopenia. Among them, there were 9 cases of paroxysmal nocturnal hemoglobinuria (PNH), 8 cases of aplastic anemia-PNH (AA-PNH), 83 cases of aplastic anemia (AA), 51 cases of myelodysplastic syndrome, 11 cases of autoimmune hemolytic anemia, 6 cases of aplastic crisis, 7 cases of iron deficiency anemia, 4 cases of megaloblastic anemia and 3 cases of hypersplenism. Results CD55 and CD59 antigens deficiency was more significant in PNH, AA-PNH patients than in other cytopenic patients. Conclusions Detection of CD55 and CD59 antigens deficiency

  11. Early and extensive CD55 loss from red blood cells supports a causal role in malarial anaemia

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    Gwamaka Moses

    2011-12-01

    Full Text Available Abstract Background Levels of complement regulatory proteins (CrP on the surface of red blood cells (RBC decrease during severe malarial anaemia and as part of cell ageing process. It remains unclear whether CrP changes seen during malaria contribute to the development of anaemia, or result from an altered RBC age distribution due to suppressive effects of malaria on erythropoiesis. Methods A cross sectional study was conducted in the north-east coast of Tanzania to investigate whether the changes in glycosylphosphatidylinositol (GPI-anchored complement regulatory proteins (CD55 and CD59 contributes to malaria anaemia. Blood samples were collected from a cohort of children under intensive surveillance for Plasmodium falciparum parasitaemia and illness. Levels of CD55 and CD59 were measured by flow cytometer and compared between anaemic (8.08 g/dl and non- anaemic children (11.42 g/dl. Results Levels of CD55 and CD59 decreased with increased RBC age. CD55 levels were lower in anaemic children and the difference was seen in RBC of all ages. Levels of CD59 were lower in anaemic children, but these differences were not significant. CD55, but not CD59, levels correlated positively with the level of haemoglobin in anaemic children. Conclusion The extent of CD55 loss from RBC of all ages early in the course of malarial anaemia and the correlation of CD55 with haemoglobin levels support the hypothesis that CD55 may play a causal role in this disorder.

  12. Role of CD97stalk and CD55 as molecular markers for prognosis and therapy of gastric carcinoma patients

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    LIU Yong; CHEN Li; PENG Shu-you; CHEN Zhou-xun; HOANG-VU C

    2005-01-01

    Objectives: To explore the mechanism of development and aggressiveness in gastric carcinomas by investigating the expression and role of CD97 and its cellular ligand CD55 in gastric carcinomas. Methods: Tumor and corresponding normal mucosal tissue, collected from 39 gastric carcinoma patients, were examined by immunohistochemistry and RT-PCR for the expression of CD97 and CD55. Results: CD97stalk was strongly stained on scattered tumor cells or small tumor cell clusters at the invasion front of gastric carcinomas. The expression of CD97stalk was frequently observed in tumors of stage Ⅰ and T1 gastric carcinoma patients. The expression of CD97stalk between Stage Ⅰ and Stage Ⅱ, Ⅲ, Ⅳ specimens showed significant difference (P<0.05), between T1 and T2, T3, T4 specimens also showed significant difference (P<0.05). Specimens with tumor invasion depth limited in mucosa of T 1 specimens showed higher positive CD55 expression than specimens with the same tumor invasion depth in T2, T3, T4 specimens, the expression of CD55 between T1 and T2, T3, T4 specimens was significantly different (P<0.05).There was strong correlation between the distribution patterns of CD97stalk and CD55 on tumor tissues (r=0.73, P<0.05). Signet ring cell carcinomas frequently contained strong CD97stalk and CD55-staining. Conclusions: Our results suggest that CD97stalk is probably involved in the growth, invasion and aggressiveness of gastric carcinomas by binding its cellular ligand CD55. CD97stalk and CD55 could be useful as molecular markers for prognosis and therapy of gastric carcinoma patients.

  13. Acceleration Factor Harmonious Particle Swarm Optimizer

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    Jie Chen; Feng Pan; Tao Cai

    2006-01-01

    A Particle Swarm Optimizer (PSO) exhibits good performance for optimization problems, although it cannot guarantee convergence to a global, or even local minimum. However, there are some adjustable parameters, and restrictive conditions, which can affect the performance of the algorithm. In this paper, the sufficient conditions for the asymptotic stability of an acceleration factor and inertia weight are deduced, the value of the inertia weight ω is enhanced to (-1, 1).Furthermore a new adaptive PSO algorithm - Acceleration Factor Harmonious PSO (AFHPSO) is proposed, and is proved to be a global search algorithm. AFHPSO is used for the parameter design of a fuzzy controller for a linear motor driving servo system. The performance of the nonlinear model for the servo system demonstrates the effectiveness of the optimized fuzzy controller and AFHPSO.

  14. Increased deposition of C3b on red cells with low CR1 and CD55 in a malaria-endemic region of western Kenya: Implications for the development of severe anemia

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    Odera Michael M

    2008-08-01

    Full Text Available Abstract Background Severe anemia due to Plasmodium falciparum malaria is a major cause of mortality among young children in western Kenya. The factors that lead to the age-specific incidence of this anemia are unknown. Previous studies have shown an age-related expression of red cell complement regulatory proteins, which protect erythrocytes from autologous complement attack and destruction. Our primary objective was to determine whether in a malaria-endemic area red cells with low levels of complement regulatory proteins are at increased risk for complement (C3b deposition in vivo. Secondarily, we studied the relationship between red cell complement regulatory protein levels and hemoglobin levels. Methods Three hundred and forty-two life-long residents of a malaria-holoendemic region of western Kenya were enrolled in a cross-sectional study and stratified by age. We measured red cell C3b, CR1, CD55, and immune complex binding capacity by flow cytometry. Individuals who were positive for malaria were treated and blood was collected when they were free of parasitemia. Analysis of variance was used to identify independent variables associated with the %C3b-positive red cells and the hemoglobin level. Results Individuals between the ages of 6 and 36 months had the lowest red cell CR1, highest %C3b-positive red cells, and highest parasite density. Malaria prevalence also reached its peak within this age group. Among children ≤ 24 months of age the %C3b-positive red cells was usually higher in individuals who were treated for malaria than in uninfected individuals with similarly low red cell CR1 and CD55. The variables that most strongly influenced the %C3b-positive red cells were age, malaria status, and red cell CD55 level. Although it did not reach statistical significance, red cell CR1 was more important than red cell CD55 among individuals treated for malaria. The variables that most strongly influenced the hemoglobin level were age, the %C3b

  15. CD55 is a key complement regulatory protein that counteracts complement-mediated inactivation of Newcastle Disease Virus.

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    Rangaswamy, Udaya S; Cotter, Christopher R; Cheng, Xing; Jin, Hong; Chen, Zhongying

    2016-08-01

    Newcastle disease virus (NDV) is being developed as an oncolytic virus for virotherapy. In this study we analysed the regulation of complement-mediated inactivation of a recombinant NDV in different host cells. NDV grown in human cells was less sensitive to complement-mediated virus inactivation than NDV grown in embryonated chicken eggs. Additionally, NDV produced from HeLa-S3 cells is more resistant to complement than NDV from 293F cells, which correlated with higher expression and incorporation of complement regulatory proteins (CD46, CD55 and CD59) into virions from HeLa-S3 cells. Further analysis of the recombinant NDVs individually expressing the three CD molecules showed that CD55 is the most potent in counteracting complement-mediated virus inactivation. The results provide important information on selecting NDV manufacture substrate to mitigate complement-mediated virus inactivation.

  16. DECAY ACCELERATING FACTOR AND COLORECTAL CANCER

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    高雪芹; 鲁艳芹; 韩金祥

    2004-01-01

    Objective: To review the significance of decay accelerating factor (DAF) in the eolorectal cancer, we searched the data from PubMed and selected the related articles for review. It was found that DAF were expressed in the adenomas and adenocarcinoma of colorectal tissues. The release of DAF in the stool of the patients was also detectable. It increased more significantly in the stool of patients with colorectal cancer than other gastrointestinal cancer. Its detection by ELISA method may render a good test for the noninvasive diagnosis of colorectal cancer. It can be concluded that DAF is expressed extensively in colorectal cancer. And the detection of DAF released in the stool of colorectal cancer patients may be a good noninvasive method for the diagnosis of colorectal cancer.

  17. Quantitation of CD55 and CD59 expression on reticulocytes and mature erythrocytes in paroxysmal nocturnal hemoglobinuria, aplastic anemia, and healthy control subjects.

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    Kim, Yeongsic; Lim, Jihyang; Kim, Myungshin; Kim, Yonggoo; Lee, Jong-Wook; Han, Kyungja

    2010-01-01

    Since PNH occasionally results in bone marrow failure, it is difficult to differentiate PNH from AA with small numbers of CD(55) (-)CD(59) (-) erythrocytes. We quantified CD55 and CD59 molecules expressed on normal reticulocytes and mature erythrocytes of paroxysmal nocturnal hemoglobinuria (PNH), aplastic anemia (AA), and normal individuals in order to determine their usefulness for differentiation between PNH and AA. A total of 56 patients (AA 39 patients, PNH 17 patients) and 10 healthy volunteers were enrolled. Two-color flow cytometric analyses were conducted using thiazole orange, anti-CD55 and CD59 monoclonal antibodies to identify CD(55) (-)CD(59) (-) reticulocytes and mature erythrocytes. Mean fluorescence level of CD(55) (+) mature erythrocytes was lowest in the PNH patients (13.2 x 10(3) MESF), and was significantly lower than in normal controls (16.7 x 10(3) MESF, p erythrocytes was lowest in the PNH subjects (24.5 x 10(3) MESF), significantly less than in normal controls (39.0 x 10(3) MESF, p erythrocytes may be useful in differentiating PNH from AA patients with small numbers of PNH-phenotype erythrocytes, and the total reticulocyte count may prove useful as a marker for PNH clone size.

  18. Decreased expression of complement regulatory proteins, CD55 and CD59, on peripheral blood leucocytes in patients with type 2 diabetes and macrovascular diseases

    Institute of Scientific and Technical Information of China (English)

    MA Xi-wen; CHANG Zhi-wen; QIN Ming-zhao; SUN Ying; HUANG Hui-lian; HE Yan

    2009-01-01

    Background Macro- and microvascular diseases are the leading cause of morbidity and mortality in diabetic patients, but their mechanisms remain unclear. Recent reports provide evidence that the levels of CD55 and CD59 are decreased in diabetic microvascular diseases. However, very little is known about the levels of CD55 and CD59, the relationship between them and carotid artery intima-media thickness, and the effects of statins on CD55 and CD59 in diabetic macrovascular diseases.Methods The mean fluorescence intensity (MFI) of CD55 and CD59 expression on peripheral blood leucocyte subsets (lymphocytes, monocytes and neutrophils) was studied using flow cytometry, and carotid artery intima-media thickness was measured using B-mode ultrasonography in 23 healthy subjects (controls), 19 patients with type 2 diabetes (T2DM), and 43 patients with type 2 diabetes and macrovascular diseases (T2DM-M). The patients with T2DM-M were assigned to two subgroups based on whether statins were used: group with statins (n=23) and group without statins (n=20).Results Compared with the controls and T2DM, the MFI of CD55 positive neutrophils was significantly lower in T2DM-M (P=0.049 vs controls and P=0.033 vs T2DM); similarly, the MFI of CD59 positive monocytes was also lower in T2DM-M (P=0.038 vs controls and P=0.043 vs T2DM). The MFI of CD59 positive neutrophils in T2DM-M was lower than in T2DM (P=0.032). The levels of CD55 and CD59 were negatively associated with age and blood pressure (r=-0.245--0.352, P=0.041-0.003), but not acute-phase reactants and carotid artery intima-media thickness. The levels of CD55 and CD59 increased after treatment with statins, but the results were not significantly different (P >0.05).Conclusions CD55 and CD59 expressions on peripheral blood leucocytes are decreased in T2DM patients with macrovascular diseases. The results suggest that the decreased levels of complement regulatory proteins might play an important role in diabetic macrovascular

  19. LU factorization for accelerator-based systems

    KAUST Repository

    Agullo, Emmanuel

    2011-12-01

    Multicore architectures enhanced with multiple GPUs are likely to become mainstream High Performance Computing (HPC) platforms in a near future. In this paper, we present the design and implementation of an LU factorization using tile algorithm that can fully exploit the potential of such platforms in spite of their complexity. We use a methodology derived from previous work on Cholesky and QR factorizations. Our contributions essentially consist of providing new CPU/GPU hybrid LU kernels, studying the impact on performance of the looking variants as well as the storage layout in presence of pivoting, tuning the kernels for two different machines composed of multiple recent NVIDIA Tesla S1070 (four GPUs total) and Fermi-based S2050 GPUs (three GPUs total), respectively. The hybrid tile LU asymptotically achieves 1 Tflop/s in single precision on both hardwares. The performance in double precision arithmetic reaches 500 Gflop/s on the Fermi-based system, twice faster than the old GPU generation of Tesla S1070. We also discuss the impact of the number of tiles on the numerical stability. We show that the numerical results of the tile LU factorization will be accurate enough for most applications as long as the computations are performed in double precision arithmetic. © 2011 IEEE.

  20. A functional SNP in the regulatory region of the decay-accelerating factor gene associates with extraocular muscle pareses in myasthenia gravis

    KAUST Repository

    Heckmann, J M

    2009-08-13

    Complement activation in myasthenia gravis (MG) may damage muscle endplate and complement regulatory proteins such as decay-accelerating factor (DAF) or CD55 may be protective. We hypothesize that the increased prevalence of severe extraocular muscle (EOM) dysfunction among African MG subjects reported earlier may result from altered DAF expression. To test this hypothesis, we screened the DAF gene sequences relevant to the classical complement pathway and found an association between myasthenics with EOM paresis and the DAF regulatory region c.-198CG SNP (odds ratio8.6; P0.0003). This single nucleotide polymorphism (SNP) results in a twofold activation of a DAF 5?-flanking region luciferase reporter transfected into three different cell lines. Direct matching of the surrounding SNP sequence within the DAF regulatory region with the known transcription factor-binding sites suggests a loss of an Sp1-binding site. This was supported by the observation that the c.-198CG SNP did not show the normal lipopolysaccharide-induced DAF transcriptional upregulation in lymphoblasts from four patients. Our findings suggest that at critical periods during autoimmune MG, this SNP may result in inadequate DAF upregulation with consequent complement-mediated EOM damage. Susceptible individuals may benefit from anti-complement therapy in addition to immunosuppression. © 2010 Macmillan Publishers Limited. All rights reserved.

  1. A functional SNP in the regulatory region of the decay-accelerating factor gene associates with extraocular muscle pareses in myasthenia gravis.

    Science.gov (United States)

    Heckmann, J M; Uwimpuhwe, H; Ballo, R; Kaur, M; Bajic, V B; Prince, S

    2010-01-01

    Complement activation in myasthenia gravis (MG) may damage muscle endplate and complement regulatory proteins such as decay-accelerating factor (DAF) or CD55 may be protective. We hypothesize that the increased prevalence of severe extraocular muscle (EOM) dysfunction among African MG subjects reported earlier may result from altered DAF expression. To test this hypothesis, we screened the DAF gene sequences relevant to the classical complement pathway and found an association between myasthenics with EOM paresis and the DAF regulatory region c.-198C>G SNP (odds ratio=8.6; P=0.0003). This single nucleotide polymorphism (SNP) results in a twofold activation of a DAF 5'-flanking region luciferase reporter transfected into three different cell lines. Direct matching of the surrounding SNP sequence within the DAF regulatory region with the known transcription factor-binding sites suggests a loss of an Sp1-binding site. This was supported by the observation that the c.-198C>G SNP did not show the normal lipopolysaccharide-induced DAF transcriptional upregulation in lymphoblasts from four patients. Our findings suggest that at critical periods during autoimmune MG, this SNP may result in inadequate DAF upregulation with consequent complement-mediated EOM damage. Susceptible individuals may benefit from anti-complement therapy in addition to immunosuppression.

  2. O papel das proteínas reguladoras do complemento CD55/CD59 em células de sangue periférico de pacientes com lúpus eritematoso sistêmico The role of CD55/CD59 complement regulatory proteins on peripheral blood cells of systemic lupus erythematosus patients

    Directory of Open Access Journals (Sweden)

    Ana Paula Alegretti

    2009-06-01

    Full Text Available CD55 e CD59 são proteínas de membrana ancoradas por glicosilfosfatidilinositol que apresentam propriedades reguladoras da ativação da cascata do complemento. Essa regulação ocorre através da inibição da C3 convertase pelo CD55 e prevenção da etapa final de polimerização do complexo de ataque à membrana pelo CD59. Deficiência na expressão dessas proteínas pode estar associada a uma maior ativação do sistema complemento, inclusive do complexo de ataque à membrana, levando à morte celular. Pacientes com lúpus eritematoso sistêmico, com anemia hemolítica e linfopenia, parecem apresentar uma deficiência adquirida de CD55 e CD59. Contudo, os mecanismos que modulam essa diminuída expressão continuam desconhecidos e o seu impacto nas manifestações do lúpus eritematoso sistêmico precisa ser mais bem estudado.CD55 and CD59 are glycosylphosphatidylinositol-anchored proteins with regulatory properties on the activating cascades of the complement system. This regulation occurs through inhibition of the C3-convertase formation by CD55, and prevention of the terminal polymerization of the membrane attack complex by CD59. Deficiency in the expression of these proteins can be associated with increased susceptibility to complement-mediated cell death. Systemic lupus erythematosus patients with hemolytic anemia and lymphopenia seem to have an acquired deficiency of CD55 and CD59 proteins. However, the mechanisms involved in this deficiency and its impact on the clinical manifestation of SLE needs to be further investigated.

  3. Accelerated Gibbs Sampling for Infinite Sparse Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Andrzejewski, D M

    2011-09-12

    The Indian Buffet Process (IBP) gives a probabilistic model of sparse binary matrices with an unbounded number of columns. This construct can be used, for example, to model a fixed numer of observed data points (rows) associated with an unknown number of latent features (columns). Markov Chain Monte Carlo (MCMC) methods are often used for IBP inference, and in this technical note, we provide a detailed review of the derivations of collapsed and accelerated Gibbs samplers for the linear-Gaussian infinite latent feature model. We also discuss and explain update equations for hyperparameter resampling in a 'full Bayesian' treatment and present a novel slice sampler capable of extending the accelerated Gibbs sampler to the case of infinite sparse factor analysis by allowing the use of real-valued latent features.

  4. Radiation Pressure Acceleration: the factors limiting maximum attainable ion energy

    CERN Document Server

    Bulanov, S S; Schroeder, C B; Bulanov, S V; Esirkepov, T Zh; Kando, M; Pegoraro, F; Leemans, W P

    2016-01-01

    Radiation pressure acceleration (RPA) is a highly efficient mechanism of laser-driven ion acceleration, with with near complete transfer of the laser energy to the ions in the relativistic regime. However, there is a fundamental limit on the maximum attainable ion energy, which is determined by the group velocity of the laser. The tightly focused laser pulses have group velocities smaller than the vacuum light speed, and, since they offer the high intensity needed for the RPA regime, it is plausible that group velocity effects would manifest themselves in the experiments involving tightly focused pulses and thin foils. However, in this case, finite spot size effects are important, and another limiting factor, the transverse expansion of the target, may dominate over the group velocity effect. As the laser pulse diffracts after passing the focus, the target expands accordingly due to the transverse intensity profile of the laser. Due to this expansion, the areal density of the target decreases, making it trans...

  5. Risk factors for accelerated atherosclerosis in young women with hyperprolactinemia.

    Science.gov (United States)

    Medic-Stojanoska, Milica; Icin, Tijana; Pletikosic, Ivana; Bajkin, Ivana; Novakovic-Paro, Jovanka; Stokic, Edita; Spasic, Dragan T; Kovacev-Zavisic, Branka; Abenavoli, Ludovico

    2015-04-01

    Prolactin is a metabolic hormone. The hypothesis is that hyperprolactinemia can cause metabolic and inflammatory changes which are associated with accelerated atherosclerotic process, but the treatment of hyperprolactinemia with dopamine agonists, leads to reversibility of these processes. The first aim of this study was to determine whether hyperprolactinemia in premenopausal women is accompanied with the increase in body mass index (BMI), changes in body composition, lipid disturbances, the presence of inflammation and changes in systolic and diastolic blood pressure as risk factors for the development of early atherosclerosis. The second aim was to know whether the therapy of hyperprolactinemia and prolactin normalization lead to improvement of the observed parameters. Twenty female patients with prolactinomas, before and during treatment with dopamine agonists and 16 healthy controls were evaluated. Prolactin, BMI, total body fat, free fat mass, total body water, total cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL) and fibrinogen as well as systolic and diastolic blood pressure were measured at baseline and during the therapy. Hyperprolactinemic patients had pathologic and significantly higher levels of prolactin (PRL) than the controls (p=0.000). The BMI, body fat, total body water (TBW), total cholesterol, triglycerides, LDL were in normal range and higher in the patients than in the controls. HDL was lower in hyperprolactinemic females than controls. The difference was significant only for body fat (fat % p=0.006; fat kg p=0.009). Fibrinogen was slightly increased in patients compared with the controls. Hyperprolactinemic patients had normal, but increased levels of systolic and diastolic blood pressure compared with the controls. The difference with border significance was found in diastolic blood pressure (p=0.065). The correlation of PRL with all the observed parameters was positive apart from HDL, but relatively

  6. 再生障碍性贫血患者PIG-A基因外显子2、4、5突变及粒细胞CD 55、CD 59的表达%Mutations of PIG-A gene Exons 2,4,5 and Granulocytic Expressions of CD55 and CD59 in Patients with Aplastic Anemia

    Institute of Scientific and Technical Information of China (English)

    李玉云; 昝丽娜; 王卫国

    2009-01-01

    背景与目的:探讨再生障碍性贫血(aplastic anemia,AA)患者PIG-A基因外显子2、4、5的突变及粒细胞表面CD55、CD59锚蛋白表达的情况. 材料与方法:从30例AA患者及20例正常对照组人群外周血提取基因组DNA,采用PCR扩增PIC-A基因外显子2、4、5,再将纯化的PCR产物双向测序检测基因序列;并用流式细胞术检测两组人群外周血粒细胞中CD55、CD59的表达. 结果:30例从患者中11例发现PIG-A基因外显子2突变,包括碱基替代、缺失、插入;PIG-A基因外显子4和外显子5突变各5例,仅为碱基替代;共5例患者有2个或2个以上外显子存在突变,正常对照组未发现突变.粒细胞CD55和CD59的表达率在AA患者PIG-A基因突变者中分别为(86.57 4±5.90)%、(88.174±5.90)%,在PIG-A基因未突变者中分别为(91.874±4.79)%、(94.24±3.76)%.均较正常对照组(97.864±1.52)%、(98.824±1.42)%显著降低(P均<0.05).结论:再生障碍性贫血患者存在PIG-A基因突变和粒细胞CD55、CD59表达缺失的现象,提示再障患者可能存在造血的克隆源性异常.%BACKGROUND AND AIM: To explore mutations of PIG-A gene exon2, exon4, exon5 and expression of CD55 and CD59 in granulocytes of patients with aplastic anemia. MATERIALS AND METHODS: Genomic DNA from peripheral blood of 30 aplastic anemia patients and 20 normal controls were extracted, and PIG-A gene exon2, exon4, exon5 were then examined with polymerase chain reaction (PCR) , nucleotide sequences were analyzed by bidirectional sequencing after PCR products were purified. The expressions of CD55 and CD59 in granulocytes from peripheral blood of the two groups above were detected by flow cytometry. RESULTS: The mutations of PIG-A gene exon2 including base substitution, deletion, insertion occurred in 11 of 30 aplastic anemia patients , the mutations of exon4, exon5 were also found in five aplastic anemia patients, with only base substitution. Two or more exon mutations were found in 5

  7. Neutron dose per fluence and weighting factors for use at high energy accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Cossairt, J.Donald; Vaziri, Kamran; /Fermilab

    2008-07-01

    In June 2007, the United States Department of Energy incorporated revised values of neutron weighting factors into its occupational radiation protection Regulation 10 CFR Part 835 as part of updating its radiation dosimetry system. This has led to a reassessment of neutron radiation fields at high energy proton accelerators such as those at the Fermi National Accelerator Laboratory (Fermilab). Values of dose per fluence factors appropriate for accelerator radiation fields calculated elsewhere are collated and radiation weighting factors compared. The results of this revision to the dosimetric system are applied to americium-beryllium neutron energy spectra commonly used for instrument calibrations. A set of typical accelerator neutron energy spectra previously measured at Fermilab are reassessed in light of the new dosimetry system. The implications of this revision are found to be of moderate significance.

  8. Acceleration of epithelial cell syndecan-1 shedding by anthrax hemolytic virulence factors

    Directory of Open Access Journals (Sweden)

    Chandhoke Vikas

    2006-02-01

    Full Text Available Abstract Background It has been recently reported that major pathogens Staphylococcus aureus and Pseudomonas aeruginosa accelerate a normal process of cell surface syndecan-1 (Synd1 ectodomain shedding as a mechanism of host damage due to the production of shedding-inducing virulence factors. We tested if acceleration of Synd1 shedding takes place in vitro upon treatment of epithelial cells with B. anthracis hemolysins, as well as in vivo during anthrax infection in mice. Results The isolated anthrax hemolytic proteins AnlB (sphingomyelinase and AnlO (cholesterol-binding pore-forming factor, as well as ClnA (B. cereus homolog of B. anthracis phosphatidyl choline-preferring phospholipase C cause accelerated shedding of Synd1 and E-cadherin from epithelial cells and compromise epithelial barrier integrity within a few hours. In comparison with hemolysins in a similar range of concentrations, anthrax lethal toxin (LT also accelerates shedding albeit at slower rate. Individual components of LT, lethal factor and protective antigen are inactive with regard to shedding. Inhibition experiments favor a hypothesis that activities of tested bacterial shedding inducers converge on the stimulation of cytoplasmic tyrosine kinases of the Syk family, ultimately leading to activation of cellular sheddase. Both LT and AnlO modulate ERK1/2 and p38 MAPK signaling pathways, while JNK pathway seems to be irrelevant to accelerated shedding. Accelerated shedding of Synd1 also takes place in DBA/2 mice challenged with Bacillus anthracis (Sterne spores. Elevated levels of shed ectodomain are readily detectable in circulation after 24 h. Conclusion The concerted acceleration of shedding by several virulence factors could represent a new pathogenic mechanism contributing to disruption of epithelial or endothelial integrity, hemorrhage, edema and abnormal cell signaling during anthrax infection.

  9. Accelerated Multiplicative Updates and Hierarchical ALS Algorithms for Nonnegative Matrix Factorization

    CERN Document Server

    Gillis, Nicolas

    2011-01-01

    Nonnegative matrix factorization (NMF) is a data analysis technique used in a great variety of applications such as text mining, image processing, hyperspectral data analysis, computational biology, and clustering. In this paper, we consider two well-known algorithms designed to solve NMF problems, namely the multiplicative updates of Lee and Seung and the hierarchical alternating least squares of Cichocki et al. We propose a simple way to significantly accelerate their convergence, based on a careful analysis of the computational cost needed at each iteration. This acceleration technique can also be applied to other algorithms, which we illustrate on the projected gradient method of Lin. The efficiency of the accelerated algorithms is empirically demonstrated on image and text datasets, and compares favorably with a state-of-the-art alternating nonnegative least squares algorithm. Finally, we provide a theoretical argument based on the properties of NMF and its solutions that explains in particular the very ...

  10. Protective effects of decay-accelerating factor on blast-induced neurotrauma in rats

    OpenAIRE

    Li, Yansong; Chavko, Mikulas; Slack, Jessica L.; Liu, Bin; McCarron, Richard M.; Ross, James D. (Dalhousie University); Dalle Lucca, Jurandir J

    2013-01-01

    Background Blast-induced neurotrauma (BINT) is the signature life threatening injury of current military casualties. Neuroinflammation is a key pathological occurrence of secondary injury contributing to brain damage after blast injury. We have recently demonstrated that blast-triggered complement activation and cytokine release are associated with BINT. Here, we evaluated if administration of the complement inhibitor recombinant human decay-accelerating factor (rhDAF) is beneficial on neuroi...

  11. Travel-related hepatitis B: risk factors and prevention using an accelerated vaccination schedule.

    Science.gov (United States)

    Keystone, Jay S

    2005-10-01

    Rates of global travel and tourism are increasing dramatically, especially to regions with medium or high endemicity for hepatitis A and B, such as Asia, Africa, Latin America, and the Middle East. International travelers to these areas should be protected against both hepatitis A and B, regardless of their anticipated length of stay. However, many travelers depart within weeks of planning their trip (too late to complete the accelerated 0-, 1-, 2-month regimen for hepatitis B), and a majority of those traveling depart without being vaccinated. Although extended-stay travelers are at high risk for hepatitis B, short-stay travelers also are at risk. The most commonly encountered risk factors for travel-related hepatitis B are casual sexual activity with a new partner, medical and dental care abroad, and in the expatriate community, adoption of children who are hepatitis B carriers. Although efficacy studies of accelerated schedules for hepatitis B immunization have not been conducted, the results of immunogenicity studies in healthy volunteers who received an accelerated, 3-dose regimen on a 0-,7-, and 21-day schedule suggest that excellent, rapid, and long-term protection will be conferred. More data are needed to assess the efficacy of accelerated schedules in persons aged >40 years and to determine whether a fourth dose of hepatitis B vaccine is needed in all age groups.

  12. Accelerated fracture healing in transgenic mice overexpressing an anabolic isoform of fibroblast growth factor 2.

    Science.gov (United States)

    Hurley, Marja M; Adams, Douglas J; Wang, Liping; Jiang, Xi; Burt, Patience Meo; Du, Erxia; Xiao, Liping

    2016-03-01

    The effect of targeted expression of an anabolic isoform of basic fibroblast growth factor (FGF2) in osteoblastic lineage on tibial fracture healing was assessed in mice. Closed fracture of the tibiae was performed in Col3.6-18 kDaFgf2-IRES-GFPsaph mice in which a 3.6 kb fragment of type I collagen promoter (Col3.6) drives the expression of only the 18 kD isoform of FGF2 (18 kDaFgf2/LMW) with green fluorescent protein-sapphire (GFPsaph) as well as Vector mice (Col3.6-IRES-GFPsaph, Vector) that did not harbor the FGF2 transgene. Radiographic, micro-CT, DEXA, and histologic analysis of fracture healing of tibiae harvested at 3, 10 and 20 days showed a smaller fracture callus but accelerated fracture healing in LMWTg compared with Vector mice. At post fracture day 3, FGF receptor 3 and Sox 9 mRNA were significantly increased in LMWTg compared with Vector. Accelerated fracture healing was associated with higher FGF receptor 1, platelet derived growth factors B, C, and D, type X collagen, vascular endothelial cell growth factor, matrix metalloproteinase 9, tartrate resistant acid phosphatase, cathepsin K, runt-related transcription factor-2, Osterix and Osteocalcin and lower Sox9, and type II collagen expression at 10 days post fracture. We postulate that overexpression of LMW FGF2 accelerated the fracture healing process due to its effects on factors that are important in chondrocyte and osteoblast differentiation and vascular invasion.

  13. Decay-Accelerating Factor Mitigates Controlled Hemorrhage-Instigated Intestinal and Lung Tissue Damage and Hyperkalemia in Swine

    Science.gov (United States)

    2011-07-01

    Decay-Accelerating Factor Mitigates Controlled Hemorrhage- Instigated Intestinal and Lung Tissue Damage and Hyperkalemia in Swine Jurandir J. Dalle...DAF treatment improved hemorrhage- induced hyperkalemia . The protective effects of DAF appear to be related to its ability to reduce tissue complement...Decay-accelerating factor mitigates controlled hemorrhage-instigated intestinal and lung tissue damage and hyperkalemia in swine 5a. CONTRACT NUMBER

  14. Factors affecting visual acuity after accelerated crosslinking in patients with progressive keratoconus

    Directory of Open Access Journals (Sweden)

    Ahmet Kırgız

    2016-06-01

    Full Text Available ABSTRACT Purpose: The present study aimed to report the outcomes of patients with progressive keratoconus who were treated via accelerated crosslinking (CXL 6 months earlier and to determine the factors that promoted improved visual acuity after treatment. Methods: This retrospective study included 35 eyes of 34 patients with progressive keratoconus who underwent CXL. Topographical measurements were obtained preoperatively and in the first, third, and sixth months postoperatively using a rotating Scheimpflug camera. The uncorrected visual acuity (UCVA, best-corrected visual acuity (BCVA, flat keratometry (K value (K1, steep K value (K2, average K value (avgK, topographic cylindrical value (Cyl, apical keratoscopy front (AKf, apical keratoscopy back (AKb, symmetry index front (SIf, symmetry index back (SIb, and thinnest point of the cornea (ThkMin were recorded. Results: At the 6-month follow-up, the mean UCVA and BCVA values were improved, and the K values remained stable. Statistically significant decreases in AKf (p=0.04 and the thinnest point of the cornea (p=0.001 and a statistically significant increase in AKb (p=0.01 were observed. A correlation analysis revealed that the preoperative BCVA, UCVA, K1, K2, avgK, AKf, and AKb values significantly affected visual acuity at the 6-month follow-up. Conclusions: Accelerated CXL is an effective treatment for the prevention or even reversal of keratoconus progression. The preoperative K values and apexes of the anterior and posterior cornea were found to affect visual acuity at 6 months after accelerated CXL. Both AKb steepening and AKf flattening appear to be important factors in the stabilization of keratometric values and improvement of visual outcomes.

  15. Carcinogenic Parasite Secretes Growth Factor That Accelerates Wound Healing and Potentially Promotes Neoplasia.

    Directory of Open Access Journals (Sweden)

    Michael J Smout

    2015-10-01

    Full Text Available Infection with the human liver fluke Opisthorchis viverrini induces cancer of the bile ducts, cholangiocarcinoma (CCA. Injury from feeding activities of this parasite within the human biliary tree causes extensive lesions, wounds that undergo protracted cycles of healing, and re-injury over years of chronic infection. We show that O. viverrini secreted proteins accelerated wound resolution in human cholangiocytes, an outcome that was compromised following silencing of expression of the fluke-derived gene encoding the granulin-like growth factor, Ov-GRN-1. Recombinant Ov-GRN-1 induced angiogenesis and accelerated mouse wound healing. Ov-GRN-1 was internalized by human cholangiocytes and induced gene and protein expression changes associated with wound healing and cancer pathways. Given the notable but seemingly paradoxical properties of liver fluke granulin in promoting not only wound healing but also a carcinogenic microenvironment, Ov-GRN-1 likely holds marked potential as a therapeutic wound-healing agent and as a vaccine against an infection-induced cancer of major public health significance in the developing world.

  16. [Determination of head scatter factors released from a scanning-type therapeutic accelerator].

    Science.gov (United States)

    Sato, Tomoharu

    2003-07-01

    The MM50 is a racetrack microtron capable of taking out photon beams and electron beams with energies of up to 50 MeV. It flattens the beam by the beam-scanning method, while the microtron MM22 utilizes a flattening filter. The head-scatter factors (hereafter called S(h)), which are important for evaluating the output of the photon beam of the MM50 and MM22, were measured using a mini-phantom and build-up cap. S(h) measured with the build-up cap showed the influence of contaminated electrons, whereas S(h) measured with the mini-phantom showed less influence, even for 50 MV photon beams. Compared with the MM22, the MM50 showed less change in S(h) according to field size and energy. The reason for this seemed to be that the MM50 has a smaller extra-focal region than other accelerators equipped with flattening filters and, therefore, can essentially be considered a point source by using the beam-scanning method without a flattening filter. This study demonstrated that photons scattered by the flattening filter used for beam flattening in typical medical accelerators mainly contribute to S(h).

  17. Theory of factors limiting high gradient operation of warm accelerating structures

    Energy Technology Data Exchange (ETDEWEB)

    Nusinovich, Gregory S. [University of Maryland; Antonsen, Thomas M. [University of Maryland; Kishek, Rami [University of Maryland

    2014-07-25

    This final report summarizes the research performed during the time period from 8/1/2010 to 7/31/2013. It consists of two parts describing our studies in two directions: (a) analysis of factors limiting operation of dielectric-loaded accelerating (DLA) structures where the main problem is the occurrence of multipactor on dielectric surfaces, and (b) studies of effects associated with either RF magnetic or RF electric fields which may cause the RF breakdown in high-gradient metallic accelerating structures. In the studies of DLA structures, at least, two accomplishments should be mentioned: the development of a 3D non-stationary, self-consistent code describing the multipactor phenomena and yielding very good agreement with some experimental data obtained in joint ANL/NRL experiments. In the metallic structures, such phenomena as the heating and melting of micro-particles (metallic dust) by RF electric and magnetic fields in single-shot and rep-rate regimes is analyzed. Also, such processes in micro-protrusions on the structure surfaces as heating and melting due to the field emitted current and the Nottingham effect are thoroughly investigated with the account for space charge of emitted current on the field emission from the tip.

  18. Acceleration of Medpor implant fibrovascularization with local vascular endothelial growth-factor injections: An experimental study

    Directory of Open Access Journals (Sweden)

    Mert Demirel

    2015-12-01

    Full Text Available Objective: Medpor is a biocompatible, high-density porous polyethylene implant that is used for multiple indications in plastic surgery. The most frequent complications associated with the Medpor implant are infection and implant exposure. The primary cause of these complications is poor fibrovascularization of the Medpor implant and poor nourishment of the overlying skin. The present experimental study aimed to determine whether vascular endothelial growth factor (VEGF could accelerate and increase Medpor implant fibrovascularization in vivo, and thereby improve local nourishment and prevent complications. Materials and Methods: The Medpor implant was inserted under the dorsal skin area in 40 Sprague-Dawley rats. 20 rats receiving local VEGF injections comprised the study group. The control group received saline injections. Fibrovascularization of the Medpor implants was compared. Results: In the rats injected with VEGF, the Medpor implant fibrovascularized faster, and there were more newly formed blood vessels, as compared with those in the control group. Conclusion: These findings have led to our use of VEGF-like agents that the accelerate angiogenesis in the Medpor implant as a means to reduce the incidence of such complications as infection and implant exposure. [Arch Clin Exp Surg 2015; 4(4.000: 196-201

  19. Accelerated Discovery of Thermoelectric Materials: Combinatorial Facility and High-Throughput Measurement of Thermoelectric Power Factor.

    Science.gov (United States)

    García-Cañadas, Jorge; Adkins, Nicholas J E; McCain, Stephen; Hauptstein, Bastian; Brew, Ashley; Jarvis, David J; Min, Gao

    2016-06-13

    A series of processes have been developed to facilitate the rapid discovery of new promising thermoelectric alloys. A novel combinatorial facility where elements are wire-fed and laser-melted was designed and constructed. Different sample compositions can be achieved by feeding different element wires at specific rates. The composition of all the samples prepared was tested by energy dispersive X-ray spectroscopy (EDS). Then, their thermoelectric properties (power factor) at room temperature were screened in a specially designed new high-throughput setup. After the screening, the thermoelectric properties can be mapped with the possibility of identifying compositional trends. As a proof-of-concept, a promising thermoelectric ternary system, Al-Fe-Ti, has been identified, demonstrating the capability of this accelerated approach.

  20. Small field detector correction factors: effects of the flattening filter for Elekta and Varian linear accelerators.

    Science.gov (United States)

    Tyler, Madelaine K; Liu, Paul Z Y; Lee, Christopher; McKenzie, David R; Suchowerska, Natalka

    2016-05-08

    Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization cham-bers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney. Small field correction factors were generated for both FF and FFF beams. Diode measured detector response was compared with a recently published mathematical relation to predict diode response corrections in small fields. The effect of flattening filter removal on detector response was quantified using a ratio of relative detector responses in FFF and FF fields for the same field size. The removal of the flattening filter was found to have a small but measurable effect on ionization chamber response with maximum deviations of less than ± 0.9% across all field sizes measured. Solid-state detectors showed an increased dependence on the flattening filter of up to ± 1.6%. Measured diode response was within ± 1.1% of the published mathematical relation for all fields up to 30 mm, independent of linac type and presence or absence of a flattening filter. For 6 MV beams, detector correction factors between FFF and FF beams are interchangeable for a linac between FF and FFF modes, providing that an additional uncertainty of up to ± 1.6% is accepted.

  1. Daintain/AIF-1 (Allograft Inflammatory Factor-1) accelerates type 1 diabetes in NOD mice

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan-Ying, E-mail: biozyy@163.com [College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041 (China); Huang, Xin-Yuan [College of Life Science and Technology, Hubei Engineering University, Xiaogan 432000 (China); Chen, Zheng-Wang [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Daintain/AIF-1 is over-expressed in the blood of NOD mice suffering from insulitis. Black-Right-Pointing-Pointer Daintain/AIF-1 stimulates white blood cell proliferation in NOD mice. Black-Right-Pointing-Pointer Daintain/AIF-1 increases blood glucose levels and triggers type 1 diabetes. Black-Right-Pointing-Pointer Daintain/AIF-1 accelerates insulitis, while its antibody prevents insulitis. Black-Right-Pointing-Pointer Daintain/AIF-1 enhances the levels of nitric oxide in the pancreases of NOD mice. -- Abstract: A large body of experimental evidence suggests that cytokines trigger pancreatic {beta}-cell death in type 1 diabetes mellitus. Daintain/AIF-1 (Allograft Inflammatory Factor-1), a specific marker for activated macrophages, is accumulated in the pancreatic islets of pre-diabetic BB rats. In the present study, we demonstrate that daintain/AIF-1 is released into blood and the levels of daintain/AIF-1 in the blood of type 1 diabetes-prone non-obese diabetic (NOD) mice suffering from insulitis are significantly higher than that in healthy NOD mice. When injected intravenously into NOD mice, daintain/AIF-1 stimulates white blood cell proliferation, increases the concentrations of blood glucose, impairs insulin expression, up-regulates nitric oxide (NO) production in pancreases and accelerates diabetes in NOD mice, while the antibody against daintain/AIF-1 delays or prevents insulitis in NOD mice. These results imply daintain/AIF-1 triggers type 1 diabetes probably via arousing immune cells activation and induction of NO production in pancreas of NOD mice.

  2. Identification of the imprinted KLF14 transcription factor undergoing human-specific accelerated evolution.

    Science.gov (United States)

    Parker-Katiraee, Layla; Carson, Andrew R; Yamada, Takahiro; Arnaud, Philippe; Feil, Robert; Abu-Amero, Sayeda N; Moore, Gudrun E; Kaneda, Masahiro; Perry, George H; Stone, Anne C; Lee, Charles; Meguro-Horike, Makiko; Sasaki, Hiroyuki; Kobayashi, Keiko; Nakabayashi, Kazuhiko; Scherer, Stephen W

    2007-05-04

    Imprinted genes are expressed in a parent-of-origin manner and are located in clusters throughout the genome. Aberrations in the expression of imprinted genes on human Chromosome 7 have been suggested to play a role in the etiologies of Russell-Silver Syndrome and autism. We describe the imprinting of KLF14, an intronless member of the Krüppel-like family of transcription factors located at Chromosome 7q32. We show that it has monoallelic maternal expression in all embryonic and extra-embryonic tissues studied, in both human and mouse. We examine epigenetic modifications in the KLF14 CpG island in both species and find this region to be hypomethylated. In addition, we perform chromatin immunoprecipitation and find that the murine Klf14 CpG island lacks allele-specific histone modifications. Despite the absence of these defining features, our analysis of Klf14 in offspring from DNA methyltransferase 3a conditional knockout mice reveals that the gene's expression is dependent upon a maternally methylated region. Due to the intronless nature of Klf14 and its homology to Klf16, we suggest that the gene is an ancient retrotransposed copy of Klf16. By sequence analysis of numerous species, we place the timing of this event after the divergence of Marsupialia, yet prior to the divergence of the Xenarthra superclade. We identify a large number of sequence variants in KLF14 and, using several measures of diversity, we determine that there is greater variability in the human lineage with a significantly increased number of nonsynonymous changes, suggesting human-specific accelerated evolution. Thus, KLF14 may be the first example of an imprinted transcript undergoing accelerated evolution in the human lineage.

  3. Identification of the imprinted KLF14 transcription factor undergoing human-specific accelerated evolution.

    Directory of Open Access Journals (Sweden)

    Layla Parker-Katiraee

    2007-05-01

    Full Text Available Imprinted genes are expressed in a parent-of-origin manner and are located in clusters throughout the genome. Aberrations in the expression of imprinted genes on human Chromosome 7 have been suggested to play a role in the etiologies of Russell-Silver Syndrome and autism. We describe the imprinting of KLF14, an intronless member of the Krüppel-like family of transcription factors located at Chromosome 7q32. We show that it has monoallelic maternal expression in all embryonic and extra-embryonic tissues studied, in both human and mouse. We examine epigenetic modifications in the KLF14 CpG island in both species and find this region to be hypomethylated. In addition, we perform chromatin immunoprecipitation and find that the murine Klf14 CpG island lacks allele-specific histone modifications. Despite the absence of these defining features, our analysis of Klf14 in offspring from DNA methyltransferase 3a conditional knockout mice reveals that the gene's expression is dependent upon a maternally methylated region. Due to the intronless nature of Klf14 and its homology to Klf16, we suggest that the gene is an ancient retrotransposed copy of Klf16. By sequence analysis of numerous species, we place the timing of this event after the divergence of Marsupialia, yet prior to the divergence of the Xenarthra superclade. We identify a large number of sequence variants in KLF14 and, using several measures of diversity, we determine that there is greater variability in the human lineage with a significantly increased number of nonsynonymous changes, suggesting human-specific accelerated evolution. Thus, KLF14 may be the first example of an imprinted transcript undergoing accelerated evolution in the human lineage.

  4. Arsenite exposure accelerates aging process regulated by the transcription factor DAF-16/FOXO in Caenorhabditis elegans.

    Science.gov (United States)

    Yu, Chan-Wei; How, Chun Ming; Liao, Vivian Hsiu-Chuan

    2016-05-01

    Arsenic is a known human carcinogen and high levels of arsenic contamination in food, soils, water, and air are of toxicology concerns. Nowadays, arsenic is still a contaminant of emerging interest, yet the effects of arsenic on aging process have received little attention. In this study, we investigated the effects and the underlying mechanisms of chronic arsenite exposure on the aging process in Caenorhabditis elegans. The results showed that prolonged arsenite exposure caused significantly decreased lifespan compared to non-exposed ones. In addition, arsenite exposure (100 μM) caused significant changes of age-dependent biomarkers, including a decrease of defecation frequency, accumulations of intestinal lipofuscin and lipid peroxidation in an age-dependent manner in C. elegans. Further evidence revealed that intracellular reactive oxygen species (ROS) level was significantly increased in an age-dependent manner upon 100 μM arsenite exposure. Moreover, the mRNA levels of transcriptional makers of aging (hsp-16.1, hsp-16.49, and hsp-70) were increased in aged worms under arsenite exposure (100 μM). Finally, we showed that daf-16 mutant worms were more sensitive to arsenite exposure (100 μM) on lifespan and failed to induce the expression of its target gene sod-3 in aged daf-16 mutant under arsenite exposure (100 μM). Our study demonstrated that chronic arsenite exposure resulted in accelerated aging process in C. elegans. The overproduction of intracellular ROS and the transcription factor DAF-16/FOXO play roles in mediating the accelerated aging process by arsenite exposure in C. elegans. This study implicates a potential ecotoxicological and health risk of arsenic in the environment.

  5. Traditional and non-traditional risk factors contribute to the development of accelerated atherosclerosis in patients with systemic lupus erythematosus

    NARCIS (Netherlands)

    de Leeuw, K.; Freire, B.; Srnit, A. J.; Bootsma, H.; Kallenberg, C. G.; Bijl, M.

    2006-01-01

    To determine risk factors of accelerated atherosclerosis in patients with systemic lupus erythematosus (SLE), 72 patients with inactive disease and 36 age- and sex-matched controls were included. The intima-media thickness (IMT) of the common carotid artery was determined by ultrasound. Traditional

  6. Identification of amino acids in the Dr adhesin required for binding to decay-accelerating factor.

    Science.gov (United States)

    Van Loy, Cristina P; Sokurenko, Evgeni V; Samudrala, Ram; Moseley, Steve L

    2002-07-01

    Members of the Dr family of adhesins of Escherichia coli recognize as a receptor the Dr(a) blood-group antigen present on the complement regulatory and signalling molecule, decay-accelerating factor (DAF). One member of this family, the Dr haemagglutinin, also binds to a second receptor, type IV collagen. Structure/function information regarding these adhesins has been limited and domains directly involved in the interaction with DAF have not been determined. We devised a strategy to identify amino acids in the Dr haemagglutinin that are specifically involved in the interaction with DAF. The gene encoding the adhesive subunit, draE, was subjected to random mutagenesis and used to complement a strain defective for its expression. The resulting mutants were enriched and screened to obtain those that do not bind to DAF, but retain binding to type IV collagen. Individual amino acid changes at positions 10, 63, 65, 75, 77, 79 and 131 of the mature DraE sequence significantly reduced the ability of the DraE adhesin to bind DAF, but not collagen. Over half of the mutants obtained had substitutions within amino acids 63-81. Analysis of predicted structures of DraE suggest that these proximal residues may cluster to form a binding domain for DAF.

  7. Overexpression of insulin-like growth factor-II induces accelerated myoblast differentiation.

    Science.gov (United States)

    Stewart, C E; James, P L; Fant, M E; Rotwein, P

    1996-10-01

    Previous studies have shown that exogenous insulin-like growth factors (IGFs) can stimulate the terminal differentiation of skeletal myoblasts in culture and have established a correlation between the rate and the extent of IGF-II secretion by muscle cell lines and the rate of biochemical and morphological differentiation. To investigate the hypothesis that autocrine secretion of IGF-II plays a critical role in stimulating spontaneous myogenic differentiation in vitro, we have established C2 muscle cell lines that stably express a mouse IGF-II cDNA under control of the strong, constitutively active Moloney sarcoma virus promoter, enabling us to study directly the effects of IGF-II overproduction. Similar to observations with other muscle cell lines, IGF-II overexpressing myoblasts proliferated normally in growth medium containing 20% fetal serum, but they underwent enhanced differentiation compared with controls when incubated in low-serum differentiation medium. Accelerated differentiation of IGF-II overexpressing C2 cells was preceded by the rapid induction of myogenin mRNA and protein expression (within 1 h, compared with 24-48 h in controls) and was accompanied by an enhanced proportion of the retinoblastoma protein in an underphosphrylated and potentially active form, by a marked increase in activity of the muscle-specific enzyme, creatine phosphokinase, by extensive myotube formation by 48 h, and by elevated secretion of IGF binding protein-5 when compared with controls. These results confirm a role for IGF-II as an autocrine/paracrine differentiation factor for skeletal myoblasts, and they define a model cell system that will be useful in determining the biochemical mechanisms of IGF action in cellular differentiation.

  8. Modulation of PBMC-decay accelerating factor (PBMC-DAF) and cytokines in rheumatoid arthritis.

    Science.gov (United States)

    Pahwa, Roma; Kumar, Uma; Das, Nibhriti

    2016-03-01

    Studies have suggested that abnormal expression of complement regulatory proteins and cytokines contribute significantly to the path-physiology of rheumatoid arthritis. In this context, Decay accelerating factor (DAF) a complement regulatory protein is gaining increased attention. With the notion that immune effecter mechanisms are all interlinked and circulating peripheral blood mononuclear cells (PBMCs) should have a role in a systemic disease like rheumatoid arthritis, we studied the modulation and significance of PBMC-DAF and cytokines in RA. Seventy-five RA patients and 75 healthy controls were recruited. Expression of DAF and cytokines (IFN-γ, IL-17A and IL-10) in the PBMCs of patients and controls was determined. Correlations among DAF, cytokines, and disease activity were evaluated by standard statistical methods. The effect of IFN-γ, IL-17A, and IL-10 on the expression of DAF in patients and controls was studied in vitro. Expression of PBMC-DAF declined in patients both at mRNA and surface level and correlated negatively with the disease activity. Expression of IFN-γ also declined in patients but correlated positively with DAF and negatively with disease activity. Expression of IL-17A and IL-10 was higher in patients. The levels correlated positively with disease activity and negatively with DAF both in patients and controls. In vitro studies indicated that IFN-γ up-regulated DAF expression in PBMCs, whereas IL-17A and IL-10 had negative effect on the same. The decline in the PBMC-DAF is a contributing factor in manifestations of RA. Cytokine environment contributes to this decline. These findings brought novel insights into the complement-cytokine axis in the path-physiology of RA.

  9. Theory of factors limiting high gradient operation of warm accelerating structures

    Energy Technology Data Exchange (ETDEWEB)

    Nusinovich, Gregory S. [Univ. of Maryland, College Park, MD (United States)

    2014-07-22

    This report consists of two parts. In the first part we describe a study of the heating of microprotrusions on surfaces of accelerating structures. This ;process is believed to lead to breakdown in these structures. Our study revealed that for current accelerator parameters melting should not occur due to space charge limitations of the current emitted by a protrusion. The second part describes a novel concept to develop THz range sources based on harmonic cyclotron masers for driving future colliders. This work was stimulated by a recent request of SLAC to develop high power, high-efficiency sources of sub-THz radiation for future high-gradient accelerators.

  10. Accelerated partial-breast irradiation with interstitial implants. Analysis of factors affecting cosmetic outcome

    Energy Technology Data Exchange (ETDEWEB)

    Ott, Oliver J.; Lotter, Michael; Fietkau, Rainer; Strnad, Vratislav [University Hospital Erlangen (Germany). Dept. of Radiation Oncology

    2009-03-15

    Purpose: To analyze patient-, disease-, and treatment-related factors for their impact on cosmetic outcome (CO) after interstitial multicatheter accelerated partial-breast irradiation (APBI). Patients and Methods: Between April 2001 and January 2005, 171 patients with early breast cancer were recruited in Erlangen for this subanalysis of the German-Austrian APBI phase II-trial. 58% (99/171) of the patients received pulsed-dose-rate (PDR), and 42% (72/171) high-dose-rate (HDR) brachytherapy. Prescribed reference dose for HDR brachytherapy was 32 Gy in eight fractions of 4 Gy, twice daily. Prescribed reference dose in PDR brachytherapy was 49.8 Gy in 83 consecutive fractions of 0.6 Gy each hour. Total treatment time was 3-4 days. Endpoint of this evaluation was the CO, graded as excellent, good, fair, or poor. Patients were divided in two groups with an excellent (n = 102) or nonexcellent (n = 69) cosmetic result. Various factors were analyzed for their impact on excellent CO. Results: The median follow-up time was 52 months (range: 21-91 months). Cosmetic results were rated as excellent in 59.6% (102/171), good in 29.8% (51/171), fair in 9.9% (17/171), and poor in 0.6% (1/171). The initial cosmetic status was significantly worse for the nonexcellent CO group (p = 0.000). The percentage of patients who received PDR brachytherapy APBI was higher in the nonexcellent CO group (68.1% vs. 51%; p = 0.026). Acute toxicity was higher in the nonexcellent CO group (24.6% vs. 12.7%; p = 0.045). Furthermore, the presence of any late toxicity was found to be associated with a worse cosmetic result (65.2% vs. 18.6%; p = 0.000). In detail, the appearance of skin hyperpigmentation (p = 0.034), breast tissue fibrosis (p = 0.000), and telangiectasia (p = 0.000) had a negative impact on CO. Conclusion: The initial, surgery-associated cosmetic status, brachytherapy modality, and the presence of acute and late toxicities were found to have an impact on overall CO. Our data have proven

  11. Study of some risk factors and accelerating factors of heart attack and the delay reasons in referring to theMazandaran Cardiac Center in 2009

    Directory of Open Access Journals (Sweden)

    Hedayat Jafari

    2009-01-01

    Full Text Available 12 3 4 (Received 21 October, 2009 ; Accepted 13 January, 2010AbstractBackground and purpose: Coronary artery disease (CAD particularly of the acute myocardial infraction (MI is one of the main causes of mortality in the developing countries. Considering the complication of the disease, the aim of this study was to investigate risk and accelerating factors of heart attack and the reason of the patients' delay in referring to Mazandaran Cardiac Center in 2009.Materials and methods: This cross-sectional study was preformed on 200 acute myocardial infarction (AMI patients. The criteria of diagnosis for AMI in this study was ST elevation of ECG, increase of CKMB above 25 in three phases and increase of Troponin-1 above 1nd/ml and also LDH increase: The demographic information, history of having specific and related disease and the heart attack accelerating factors and the reason of delay in referring to cardiac center was recorded in questionnaire. The collected data were coded, then analyzed by X2 test and ANOVA test using u. SPSS soft wave.Results: Of 200 patients under study, 57% were male. With mean age and BMI of 62.02 years and of 26.66 respectively. The major risk factor in incidence of heart attack in this study first was high blood pressure (24.7 % and the second one was diabetes mellitus 15.5 %. The accelerating factors of heart attack were heavy physical activity (25.3 %, sudden wake ups (25.2 %, and mental work along with tension (12.6 % respectively.Conclusion: Considering the risk factors and heart attack accelerating factors, providing proper education to the public, it is possible it reduce the number of heart attack cases and implement proper strategy to reduce the delay in referring of such patients to a cardiac center. J Mazand Univ Med Sci 2009; 19(73: 69-74 (Persian.

  12. ADHD as risk factor for early onset and heightened adult problem severity of illicit substance use: An Accelerated Gateway Model

    OpenAIRE

    Dunne, Eugene M.; Hearn, Lauren E.; Rose, Jonathan; Latimer, William W.

    2014-01-01

    The primary aims of the present study were to assess ADHD history as a risk factor for earlier initiation and current use of licit and illicit substances among a sample of drug using adults. It was hypothesized that ADHD history would accelerate the Gateway Theory of drug use. Participants included 941 drug-using African American and Caucasian individuals in Baltimore, Maryland. The sample consisted of 124 (13.2%) participants who reported a history of ADHD and 817 (86.8%) who reported no his...

  13. Time to accelerate integration of human factors and ergonomics in patient safety.

    Science.gov (United States)

    Gurses, Ayse P; Ozok, A Ant; Pronovost, Peter J

    2012-04-01

    Progress toward improving patient safety has been slow despite engagement of the health care community in improvement efforts. A potential reason for this sluggish pace is the inadequate integration of human factors and ergonomics principles and methods in these efforts. Patient safety problems are complex and rarely caused by one factor or component of a work system. Thus, health care would benefit from human factors and ergonomics evaluations to systematically identify the problems, prioritize the right ones, and develop effective and practical solutions. This paper gives an overview of the discipline of human factors and ergonomics and describes its role in improving patient safety. We provide examples of how human factors and ergonomics principles and methods have improved both care processes and patient outcomes. We provide five major recommendations to better integrate human factors and ergonomics in patient safety improvement efforts: build capacity among health care workers to understand human factors and ergonomics, create market forces that demand the integration of human factors and ergonomics design principles into medical technologies, increase the number of human factors and ergonomic practitioners in health care organizations, expand investments in improvement efforts informed by human factors and ergonomics, and support interdisciplinary research to improve patient safety. In conclusion, human factors and ergonomics must play a more prominent role in health care if we want to increase the pace in improving patient safety.

  14. Investigation of reliability attributes and accelerated stress factors of terrestrial solar cells. First annual report

    Energy Technology Data Exchange (ETDEWEB)

    Prince, J.L.; Lathrop, J.W.

    1979-05-01

    The results of accelerated stress testing of four different types of silicon terrestrial solar cells are discussed. The accelerated stress tests used included bias-temperature tests, bias-temperature-humidity tests, thermal cycle and thermal shock tests, and power cycle tests. Characterization of the cells was performed before stress testing and at periodic down-times, using electrical measurement, visual inspection, and metal adherence pull tests. Electrical parameters measured included short-circuit current, I/sub sc/, open circuit voltage, V/sub oc/, and output power, voltage, and current at the maximum power point, P/sub m/, V/sub m/, and I/sub m/ respectively. Incorporated in the report are the distributions of the prestress electrical data for all cell types. Data was also obtained on cell series and shunt resistance. Significant differences in the response to the various stress tests was observed between cell types. On the basis of the experience gained in this research work, a suggested Reliability Qualification Test Schedule was developed.

  15. Investigation of reliability attributes and accelerated stress factors on terrestrial solar cells. Third annual report

    Energy Technology Data Exchange (ETDEWEB)

    Lathrop, J.W.; Hartman, R.A.; Saylor, C.R.

    1981-01-01

    The third year of the accelerated reliability testing program concentrated on electrical measurement instrumentation and in modeling cell behavior in the second quadrant. In addition, some preliminary work was done on correlating cell color changes with electrical degradation. Not reported are results of continuing accelerated stress tests on state of the art cells. A number of new cells were added to the program, but not in time for sufficient data to be obtained, while the older cells are undergoing extended test periods and new data are not yet available on them. The all-digital, microprocessor controlled, short interval tester, which was designed and fabricated, has replaced the manual measurement procedure formerly used. This has improved measurement accuracy and repeatability, reduced measurement time, and through coordinated data management procedures, eliminated data errors. A complete description of the tester including schematics and software is given and its operating procedures described. A computer model, based on the thermal and electrical properties of the cells and encapsulating materials, was developed to relate cell temperature to electrical characteristics in the second quadrant. This model adequately predicted the behavior of both encapsulated and unencapsulated cells, although accurate temperature measurements on encapsulated cells were difficult to obtain. In addition, only cells of one type were used for comparison and other cell types may require different parameter values for fitting. Use of the model should permit the prediction of a cell's sensitivity to degradation in the second quadrant. The computer program is listed together with a description of its operation.

  16. Students' Perceptions of Factors That Contribute to Risk and Success in Accelerated High School Courses

    Science.gov (United States)

    Shaunessy-Dedrick, Elizabeth; Suldo, Shannon M.; Roth, Rachel A.; Fefer, Sarah A.

    2015-01-01

    In this qualitative study, we investigated 15 successful and 15 struggling high school students, perceived stressors, coping strategies, and intrapersonal and environmental factors that students perceive to influence their success in college-level courses. We found that students' primary sources of stress involved meeting numerous academic demands…

  17. Hepatocyte Growth Factor Prevents Acute Renal Failure of Accelerates Renal Regeneration in mice

    Science.gov (United States)

    Kawaida, Kouichi; Matsumoto, Kunio; Shimazu, Hisaaki; Nakamura, Toshikazu

    1994-05-01

    Although acute renal failure is encountered with administration of nephrotoxic drugs, ischemia, or unilateral nephrectomy, there has been no effective drug which can be used in case of acute renal failure. Hepatocyte growth factor (HGF) is a potent hepatotropic factor for liver regeneration and is known to have mitogenic, motogenic, and morphogenic activities for various epithelial cells, including renal tubular cells. Intravenous injection of recombinant human HGF into mice remarkably suppressed increases in blood urea nitrogen and serum creatinine caused by administration of cisplatin, a widely used antitumor drug, or HgCl_2, thereby indicating that HGF strongly prevented the onset of acute renal dysfunction. Moreover, exogenous HGF stimulated DNA synthesis of renal tubular cells after renal injuries caused by HgCl_2 administration and unilateral nephrectomy and induced reconstruction of the normal renal tissue structure in vivo. Taken together with our previous finding that expression of HGF was rapidly induced after renal injuries, these results allow us to conclude that HGF may be the long-sought renotropic factor for renal regeneration and may prove to be effective treatment for patients with renal dysfunction, especially that caused by cisplatin.

  18. Identification of the Imprinted KLF14 Transcription Factor Undergoing Human-Specific Accelerated Evolution

    OpenAIRE

    Layla Parker-Katiraee; Carson, Andrew R.; Takahiro Yamada; Philippe Arnaud; Robert Feil; Abu-Amero, Sayeda N.; Moore, Gudrun E; Masahiro Kaneda; Perry, George H.; Stone, Anne C.; Charles Lee; Makiko Meguro-Horike; Hiroyuki Sasaki; Keiko Kobayashi; Kazuhiko Nakabayashi

    2007-01-01

    Imprinted genes are expressed in a parent-of-origin manner and are located in clusters throughout the genome. Aberrations in the expression of imprinted genes on human Chromosome 7 have been suggested to play a role in the etiologies of Russell-Silver Syndrome and autism. We describe the imprinting of KLF14, an intronless member of the Krüppel-like family of transcription factors located at Chromosome 7q32. We show that it has monoallelic maternal expression in all embryonic and extra-embryon...

  19. Identification of the imprinted KLF14 transcription factor undergoing human-specific accelerated evolution

    OpenAIRE

    Parker-Katiraee, L.; Carson, A.R.; Yamada, T; Meguro-Horike, M.; Nakabayashi, K.; Scherer, S.W.; Arnaud, P.; Feil, R; Abu-Amero, S. N.; Moore, G.E.; Kaneda, M.; Sasaki, H.; Perry, G. H.; Stone, A C; Lee, C

    2007-01-01

    Imprinted genes are expressed in a parent-of-origin manner and are located in clusters throughout the genome. Aberrations in the expression of imprinted genes on human Chromosome 7 have been suggested to play a role in the etiologies of Russell-Silver Syndrome and autism. We describe the imprinting of KLF14, an intronless member of the Krüppel-like family of transcription factors located at Chromosome 7q32. We show that it has monoallelic maternal expression in all embryonic and extra-embryon...

  20. Accelerated circumferential strain quantification of the left ventricle using CIRCOME: simulation and factor analysis

    Science.gov (United States)

    Moghaddam, Abbas N.; Finn, J. Paul

    2008-03-01

    Circumferential strain of the left ventricle reflects myocardial contractility and is considered a key index of cardiac function. It is also an important parameter in the quantitative evaluation of heart failure. Circumferential compression encoding, CIRCOME, is a novel method in cardiac MRI to evaluate this strain non-invasively and quickly. This strain encoding technique avoids the explicit measurement of the displacement field and does not require calculation of strain through spatial differentiation. CIRCOME bypasses these two time-consuming and noise sensitive steps by directly using the frequency domain (k-space) information from radially tagged myocardium, before and after deformation. It uses the ring-shaped crown region of the k-space, generated by the taglines, to reconstruct circumferentially compression-weighted images of the heart before and after deformation. CIRCOME then calculates the circumferential strain through relative changes in the compression level of corresponding regions before and after deformation. This technique can be implemented in 3D as well as 2D and may be employed to estimate the overall global or regional circumferential strain. The main parameters that affect the accuracy of this method are spatial resolution, signal to noise ratio, eccentricity of the center of radial taglines their fading and their density. Also, a variety of possible image reconstruction and filtering options may influence the accuracy of the method. This study describes the pulse sequence, algorithm, influencing factors and limiting criteria for CIRCOME and provides the simulated results.

  1. A cytokine-like factor astakine accelerates the hemocyte production in Pacific oyster Crassostrea gigas.

    Science.gov (United States)

    Li, Yiqun; Jiang, Shuai; Li, Meijia; Xin, Lusheng; Wang, Lingling; Wang, Hao; Qiu, Limei; Song, Linsheng

    2016-02-01

    Astakine has been reported to be a hematopoietic growth factor of prokineticin homolog firstly found in arthropods freshwater crayfish Pacifastacus leniusculus. In the present study, an astakine homologous gene was identified from Pacific oyster Crassostrea gigas (designated CgAstakine). The full length cDNA of CgAstakine encoded a polypeptide of 103 amino acids containing a prokineticin (PK) domain homologous to that in astakine from freshwater crayfish P. leniusculus. The deduced amino acid sequence of CgAstakine shared higher similarity with those of other invertebrate astakines than prokineticins from vertebrates. The mRNA of CgAstakine was highly expressed in hepatopancreas and adductor muscle of oyster, while the CgAstakine protein was mainly distributed in hepatopancreas, gill and hemocytes. The mRNA expression of CgAstakine in hemocytes was significantly increased (p oyster hemocytes were incubated with 5 μg/mL recombinant CgAstakine protein (rCgAstakine) for 24 h in vitro, the proliferation of hemocytes was significantly increased to 1.89 fold of that in control group (p oyster hemocytes was significantly upregulated (2.45 fold of that in control group, p oysters were received an injection of rCgAstakine (0.5 μg/g). These results collectively indicated that CgAstakine could modulate the hemocytes proliferation both in vitro and in vivo, and probably involved in the hematopoietic process fighting against the invasion of foreign pathogens.

  2. The Accelerating And Constraining Factors Of The Coordinated And Balanced Development Of Regions

    Directory of Open Access Journals (Sweden)

    Vladimir Stepanovich Bochko

    2015-03-01

    Full Text Available In the article, the hypothesis that the modern industrial-technological process causes complication of socio-economic space and conducts to amplification its integrity, which, in turn, causes the need for the coordinated and balanced development, is proved. The process of complication of economic space is revealed as a result of number growth of communications caused by creation of the enterprises and organizations, by the change of structure of manufacture and increase of an educational level of the population. The characteristics of a new quality of economic space are given. The factors of the coordinated and balanced development of territories are allocated. The contents «a commercial combination» is shown. The necessity of transition to the system innovation thinking in conditions of becoming complicated economic space is proved. The idea of use «rebalancing of the economy « as a new vision of equation in conditions of crisis situations is offered. The conclusion is made that the result of theoretical and practical searches should become formation vital stability of development of territories, which is provided with intelligence — technological and moral — ethical level of the population, living on it

  3. A Tandem Repeat in Decay Accelerating Factor 1 Is Associated with Severity of Murine Mercury-Induced Autoimmunity

    Directory of Open Access Journals (Sweden)

    David M. Cauvi

    2014-01-01

    Full Text Available Decay accelerating factor (DAF, a complement-regulatory protein, protects cells from bystander complement-mediated lysis and negatively regulates T cells. Reduced expression of DAF occurs in several systemic autoimmune diseases including systemic lupus erythematosus, and DAF deficiency exacerbates disease in several autoimmune models, including murine mercury-induced autoimmunity (mHgIA. Daf1, located within Hmr1, a chromosome 1 locus associated in DBA/2 mice with resistance to mHgIA, could be a candidate. Here we show that reduced Daf1 transcription in lupus-prone mice was not associated with a reduction in the Daf1 transcription factor SP1. Studies of NZB mice congenic for the mHgIA-resistant DBA/2 Hmr1 locus suggested that Daf1 expression was controlled by the host genome and not the Hmr1 locus. A unique pentanucleotide repeat variant in the second intron of Daf1 in DBA/2 mice was identified and shown in F2 intercrosses to be associated with less severe disease; however, analysis of Hmr1 congenics indicated that this most likely reflected the presence of autoimmunity-predisposing genetic variants within the Hmr1 locus or that Daf1 expression is mediated by the tandem repeat in epistasis with other genetic variants present in autoimmune-prone mice. These studies argue that the effect of DAF on autoimmunity is complex and may require multiple genetic elements.

  4. Model for Initiation of Quality Factor Degradation at High Accelerating Fields in Superconducting Radio-Frequency Cavaties

    Energy Technology Data Exchange (ETDEWEB)

    Dzyuba, A.; /Fermilab /Novosibirsk State U.; Romanenko, A.; /Fermilab; Cooley, L.D.; /Fermilab

    2010-07-13

    A model for the onset of the reduction in SRF cavity quality factor, the so-called Q-drop, at high accelerating electric fields is presented. Since magnetic fields at the cavity equator are tied to accelerating electric fields by a simple geometric factor, the onset of magnetic flux penetration determines the onset of Q-drop. We consider breakdown of the surface barrier at triangular grooves to predict the magnetic field of first flux penetration H{sub pen}. Such defects were argued to be the worst case by Buzdin and Daumens, [1998 Physica C 294 257], whose approach, moreover, incorporates both the geometry of the groove and local contamination via the Ginzburg-Landau parameter {kappa}. Since previous Q-drop models focused on either topography or contamination alone, the proposed model allows new comparisons of one effect in relation to the other. The model predicts equivalent reduction of H{sub pen} when either roughness or contamination were varied alone, so smooth but dirty surfaces limit cavity performance about as much as rough but clean surfaces do. Still lower H{sub pen} was predicted when both effects were combined, i.e. contamination should exacerbate the negative effects of roughness and vice-versa. To test the model with actual data, coupons were prepared by buffered chemical polishing and electropolishing, and stylus profilometry was used to obtain distributions of angles. From these data, curves for surface resistance generated by simple flux flow as a function of magnetic field were generated by integrating over the distribution of angles for reasonable values of {kappa}. This showed that combined effects of roughness and contamination indeed reduce the Q-drop onset field by {approx}20%, and that that contamination contributes to Q-drop as much as roughness. The latter point may be overlooked by SRF cavity research, since access to the cavity interior by spectroscopy tools is very difficult, whereas optical images have become commonplace. The model

  5. Comparison of Tissue-Maximum Ratio and Output Factors ESTRO booklet with 6 for Siemens Primus accelerator Mevatron; Comparacion de Tissue-Maximum Ratio y Output Factors con el ESTYRO booklet 6 para un acelerador Siemens Primus Mevatron

    Energy Technology Data Exchange (ETDEWEB)

    Lupiani Castellanos, J.; Quinones Rodriguez, L. A.; Richarte Reina, J. M.; Ramos Caballero, L. J.; Angulo Pain, E.; Castro Ramierez, I. J.; Iborra Oquendo, M. A.; Urena Llinares, A.

    2011-07-01

    The ESTRO Booklet 6 gives the numerical data collected in four different sizes and different accelerators for different beam qualities. Although the end of this guide is the calculation and verification of monitor units, the data we have used Siemens Primus accelerator Mevatron 6 MV photons to perform quality control of the experimental measurements for the tissue-maximum ratio (TMR) and the output factor (OF) in air yen dummy.

  6. Platelet factor XIII increases the fibrinolytic resistance of platelet-rich clots by accelerating the crosslinking of alpha 2-antiplasmin to fibrin

    Science.gov (United States)

    Reed, G. L.; Matsueda, G. R.; Haber, E.

    1992-01-01

    Platelet clots resist fibrinolysis by plasminogen activators. We hypothesized that platelet factor XIII may enhance the fibrinolytic resistance of platelet-rich clots by catalyzing the crosslinking of alpha 2-antiplasmin (alpha 2AP) to fibrin. Analysis of plasma clot structure by polyacrylamide gel electrophoresis and immunoblotting revealed accelerated alpha 2AP-fibrin crosslinking in platelet-rich compared with platelet-depleted plasma clots. A similar study of clots formed with purified fibrinogen (depleted of factor XIII activity), isolated platelets, and specific factor XIII inhibitors indicated that this accelerated crosslinking was due to the catalytic activity of platelet factor XIII. Moreover, when washed platelets were aggregated by thrombin, there was evidence of platelet factor XIII-mediated crosslinking between platelet alpha 2AP and platelet fibrin(ogen). Specific inhibition (by a monoclonal antibody) of the alpha 2AP associated with washed platelet aggregates accelerated the fibrinolysis of the platelet aggregate. Thus in platelet-rich plasma clots, and in thrombin-induced platelet aggregates, platelet factor XIII actively formed alpha 2AP-fibrin crosslinks, which appeared to enhance the resistance of platelet-rich clots to fibrinolysis.

  7. Tumor necrosis factoraccelerates the resolution of established pulmonary fibrosis in mice by targeting profibrotic lung macrophages.

    Science.gov (United States)

    Redente, Elizabeth F; Keith, Rebecca C; Janssen, William; Henson, Peter M; Ortiz, Luis A; Downey, Gregory P; Bratton, Donna L; Riches, David W H

    2014-04-01

    Idiopathic pulmonary fibrosis (IPF) is a relentless, fibrotic parenchymal lung disease in which alternatively programmed macrophages produce profibrotic molecules that promote myofibroblast survival and collagen synthesis. Effective therapies to treat patients with IPF are lacking, and conventional therapy may be harmful. We tested the hypothesis that therapeutic lung delivery of the proinflammatory cytokine tumor necrosis factor (TNF)-α into wild-type fibrotic mice would reduce the profibrotic milieu and accelerate the resolution of established pulmonary fibrosis. Fibrosis was assessed in bleomycin-instilled wild-type and TNF-α(-/-) mice by measuring hydroxyproline levels, static compliance, and Masson's trichrome staining. Macrophage infiltration and programming status was assessed by flow cytometry of enzymatically digested lung and in situ immunostaining. Pulmonary delivery of TNF-α to wild-type mice with established pulmonary fibrosis was found to reduce their fibrotic burden, to improve lung function and architecture, and to reduce the number and programming status of profibrotic alternatively programmed macrophages. In contrast, fibrosis and alternative macrophage programming were prolonged in bleomycin-instilled TNF-α(-/-) mice. To address the role of the reduced numbers of alternatively programmed macrophages in the TNF-α-induced resolution of established pulmonary fibrosis, we conditionally depleted macrophages in MAFIA (MAcrophage Fas-Induced Apoptosis) mice. Conditional macrophage depletion phenocopied the resolution of established pulmonary fibrosis observed after therapeutic TNF-α delivery. Taken together, our results show for the first time that TNF-α is involved in the resolution of established pulmonary fibrosis via a mechanism involving reduced numbers and programming status of profibrotic macrophages. We speculate that pulmonary delivery of TNF-α or augmenting its signaling pathway represent a novel therapeutic strategy to resolve

  8. Impact of the Number of Cautionary and/or Unsuitable Risk Factors on Outcomes After Accelerated Partial Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wobb, Jessica; Wilkinson, J. Ben [Department of Radiation Oncology, Beaumont Cancer Institute, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan (United States); Shah, Chirag [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States); Mitchell, Christina; Wallace, Michelle; Ye, Hong; Stromberg, Jannifer; Grills, Inga [Department of Radiation Oncology, Beaumont Cancer Institute, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan (United States); Chen, Peter Y., E-mail: PChen@beaumont.edu [Department of Radiation Oncology, Beaumont Cancer Institute, Oakland University William Beaumont School of Medicine, Royal Oak, Michigan (United States)

    2013-09-01

    Purpose: To examine clinical outcomes of accelerated partial-breast irradiation (APBI) stratified by the number of American Society for Radiation Oncology consensus statement cautionary/unsuitable risk factors (RFs) present. Methods and Materials: A total of 692 patients were treated with APBI at a single institution between April 1993 and January 2012 using interstitial (n=195), balloon (n=292), and 3-dimensional conformal radiation therapy (n=205) techniques. Clinical outcomes were evaluated by risk group and number of RFs. Results: Median follow-up was 5.2 years (range, 0-18.3 years). Most patients were classified as suitable (n=240, 34%) or cautionary (n=343, 50%) risk, whereas 16% (n=109) were unsuitable. In patients with increasing total RFs (1 RF, 2 RF, 3+ RF), higher rates of grade 3 histology (10% vs 18% vs 32%, P<.001), estrogen receptor negativity (0 vs 12% vs 29%, P<.001), close/positive margins (0 vs 6% vs 17%, P<.001), and use of adjuvant chemotherapy (3% vs 12% vs 33%, P<.001) were noted. When pooling cautionary and unsuitable patients, increased ipsilateral breast tumor recurrence/regional recurrence was most notable for patients with 3 or more combined RFs versus 2 or fewer combined RFs (P<.001). Conclusions: Patients with 3 or more cautionary or unsuitable RFs may be at risk for higher local, regional, and distant recurrence after breast-conserving therapy using APBI. Patients with 2 or fewer total RFs have 98% locoregional control at 5 years. Inclusion of total number of RFs in future risk stratification schemes for APBI may be warranted.

  9. Impact accelerations

    Science.gov (United States)

    Vongierke, H. E.; Brinkley, J. W.

    1975-01-01

    The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

  10. FFAGS for rapid acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Carol J. Johnstone and Shane Koscielniak

    2002-09-30

    When large transverse and longitudinal emittances are to be transported through a circular machine, extremely rapid acceleration holds the advantage that the beam becomes immune to nonlinear resonances because there is insufficient time for amplitudes to build up. Uncooled muon beams exhibit large emittances and require fast acceleration to avoid decay losses and would benefit from this style of acceleration. The approach here employs a fixed-field alternating gradient or FFAG magnet structure and a fixed frequency acceleration system. Acceptance is enhanced by the use only of linear lattice elements, and fixed-frequency rf enables the use of cavities with large shunt resistance and quality factor.

  11. Medium-Term Stability of the Photon Beam Energy of An Elekta CompactTM Linear Accelerator Based on Daily Measurements of Beam Quality Factor

    Directory of Open Access Journals (Sweden)

    Mohammad Amin Mosleh-Shirazi

    2016-04-01

    Full Text Available Introduction In this study, we aimed to assess the medium-term energy stability of a 6MV Elekta CompactTM linear accelerator. To the best of our knowledge, this is the first published article to evaluate this linear accelerator in terms of energy stability. As well as investigating the stability of the linear accelerator energy over a period of several weeks, the results will be useful for estimation of the required tolerance values for the beam quality factor (BQF of the PTW QUICKCHECK weblineTM (QCW daily checking device. Materials and Methods Over a 13 week period of routine clinical service, 52 daily readings of BQF were taken and then analyzed for a 10×10 cm2 field. Results No decreasing or increasing trend in BQF was observed over the study period. The mean BQF value was estimated at 5.4483 with a standard deviation (SD of 0.0459 (0.8%. The mean value was only 0.1% different from the baseline value. Conclusion The results of this medium-term stability study of the Elekta Compact linear accelerator energy showed that 96.2% of the observed BQF values were within ±1.3% of the baseline value. This can be considered to be within the recommended tolerance for linear accelerator photon beam energy. If an approach of applying ±3 SD is taken, the tolerance level for BQF may be suggested to be set at ±2.5%. However, further research is required to establish a relationship between BQF value and the actual changes in beam energy and penetrative quality.

  12. Future accelerators (?)

    Energy Technology Data Exchange (ETDEWEB)

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  13. Genes and environment as predisposing factors in autoimmunity: acceleration of spontaneous thyroiditis by dietary iodide in NOD.H2(h4) mice.

    Science.gov (United States)

    Kolypetri, Panayota; King, Justin; Larijani, Mani; Carayanniotis, George

    2015-01-01

    In the field of autoimmune thyroiditis, NOD.H2(h4) mice have attracted significant and increasing attention since they not only develop spontaneous disease but they present thyroiditis with accelerated incidence and severity if they ingest iodide through their drinking water. This animal model highlights the interplay between genetic and dietary factors in the triggering of autoimmune disease and offers new opportunities to study immunoregulatory parameters influenced by both genes and environment. Here, we review experimental findings with this mouse model of thyroiditis.

  14. Tumor necrosis factor-α-accelerated degradation of type I collagen in human skin is associated with elevated matrix metalloproteinase (MMP)-1 and MMP-3 ex vivo

    DEFF Research Database (Denmark)

    Ågren, Magnus S; Schnabel, Reinhild; Christensen, Lise H

    2015-01-01

    /ml) in the absence or presence of the nonselective MMP inhibitor GM6001 for 8 days. The basal culture conditions promoted type I collagen catabolism that was accelerated by TNF-α (p...Tumor necrosis factor (TNF)-α induces matrix metalloproteinases (MMPs) that may disrupt skin integrity. We have investigated the effects and mechanisms of exogenous TNF-α on collagen degradation by incubating human skin explants in defined serum-free media with or without TNF-α (10ng...... were associated with increased collagen degradation. TNF-α increased secretion of MMP-1 (p

  15. FFAGS FOR MUON ACCELERATION.

    Energy Technology Data Exchange (ETDEWEB)

    BERG,J.S.KAHN,S.PALMER,R.TRBOJEVIC,D.JOHNSTONE,C.KEIL,Y.OGITSU,T.OHMORI,C.SESSLER,A.KOSCIELNIAK,S.

    2003-06-26

    Due to their finite lifetime, muons must be accelerated very rapidly. It is challenging to make the magnets ramp fast enough to accelerate in a synchrotron, and accelerating in a linac is very expensive. One can use a recirculating accelerator (like CEBAF), but one needs a different arc for each turn, and this limits the number of turns one can use to accelerate, and therefore requires significant amounts of RF to achieve the desired energy gain. An alternative method for muon acceleration is using a fixed field alternating gradient (FFAG) accelerator. Such an accelerator has a very large energy acceptance (a factor of two or three), allowing one to use the same arc with a magnetic field that is constant over time. Thus, one can in principle make as many turns as one can tolerate due to muon decay, therefore reducing the RF cost without increasing the arc cost. This paper reviews the current status of research into the design of FFAGs for muon acceleration. Several current designs are described and compared. General design considerations are also discussed.

  16. Accelerating Value Creation with Accelerators

    DEFF Research Database (Denmark)

    Jonsson, Eythor Ivar

    2015-01-01

    accelerator programs. Microsoft runs accelerators in seven different countries. Accelerators have grown out of the infancy stage and are now an accepted approach to develop new ventures based on cutting-edge technology like the internet of things, mobile technology, big data and virtual reality. It is also...... with the traditional audit and legal universes and industries are examples of emerging potentials both from a research and business point of view to exploit and explore further. The accelerator approach may therefore be an Idea Watch to consider, no matter which industry you are in, because in essence accelerators...

  17. Accelerating Value Creation with Accelerators

    DEFF Research Database (Denmark)

    Jonsson, Eythor Ivar

    2015-01-01

    Accelerators can help to accelerate value creation. Accelerators are short-term programs that have the objective of creating innovative and fast growing ventures. They have gained attraction as larger corporations like Microsoft, Barclays bank and Nordea bank have initiated and sponsored accelera......Accelerators can help to accelerate value creation. Accelerators are short-term programs that have the objective of creating innovative and fast growing ventures. They have gained attraction as larger corporations like Microsoft, Barclays bank and Nordea bank have initiated and sponsored...... an approach to facilitate implementation and realization of business ideas and is a lucrative approach to transform research into ventures and to revitalize regions and industries in transition. Investors have noticed that the accelerator approach is a way to increase the possibility of success by funnelling...

  18. Accelerated evolution of functional plastid rRNA and elongation factor genes due to reduced protein synthetic load after the loss of photosynthesis in the chlorophyte alga Polytoma.

    Science.gov (United States)

    Vernon, D; Gutell, R R; Cannone, J J; Rumpf, R W; Birky, C W

    2001-09-01

    Polytoma obtusum and Polytoma uvella are members of a clade of nonphotosynthetic chlorophyte algae closely related to Chlamydomonas humicola and other photosynthetic members of the Chlamydomonadaceae. Descended from a nonphotosynthetic mutant, these obligate heterotrophs retain a plastid (leucoplast) with a functional protein synthetic system, and a plastid genome (lpDNA) with functional genes encoding proteins required for transcription and translation. Comparative studies of the evolution of genes in chloroplasts and leucoplasts can identify modes of selection acting on the plastid genome. Two plastid genes--rrn16, encoding the plastid small-subunit rRNA, and tufA, encoding elongation factor Tu--retain their functions in protein synthesis after the loss of photosynthesis in two nonphotosynthetic Polytoma clades but show a substantially accelerated rate of base substitution in the P. uvella clade. The accelerated evolution of tufA is due, at least partly, to relaxed codon bias favoring codons that can be read without wobble, mainly in three amino acids. Selection for these codons may be relaxed because leucoplasts are required to synthesize fewer protein molecules per unit time than are chloroplasts (reduced protein synthetic load) and thus require a lower rate of synthesis of elongation factor Tu. Relaxed selection due to a lower protein synthetic load is also a plausible explanation for the accelerated rate of evolution of rrn16, but the available data are insufficient to test the hypothesis for this gene. The tufA and rrn16 genes in Polytoma oviforme, the sole member of a second nonphotosynthetic clade, are also functional but show no sign of relaxed selection.

  19. Dielectric assist accelerating structure

    Science.gov (United States)

    Satoh, D.; Yoshida, M.; Hayashizaki, N.

    2016-01-01

    A higher-order TM02 n mode accelerating structure is proposed based on a novel concept of dielectric loaded rf cavities. This accelerating structure consists of ultralow-loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure. Unlike conventional dielectric loaded accelerating structures, most of the rf power is stored in the vacuum space near the beam axis, leading to a significant reduction of the wall loss, much lower than that of conventional normal-conducting linac structures. This allows us to realize an extremely high quality factor and a very high shunt impedance at room temperature. A simulation of a 5 cell prototype design with an existing alumina ceramic indicates an unloaded quality factor of the accelerating mode over 120 000 and a shunt impedance exceeding 650 M Ω /m at room temperature.

  20. LIBO accelerates

    CERN Multimedia

    2002-01-01

    The prototype module of LIBO, a linear accelerator project designed for cancer therapy, has passed its first proton-beam acceleration test. In parallel a new version - LIBO-30 - is being developed, which promises to open up even more interesting avenues.

  1. RECIRCULATING ACCELERATION

    Energy Technology Data Exchange (ETDEWEB)

    BERG,J.S.; GARREN,A.A.; JOHNSTONE,C.

    2000-04-07

    This paper compares various types of recirculating accelerators, outlining the advantages and disadvantages of various approaches. The accelerators are characterized according to the types of arcs they use: whether there is a single arc for the entire recirculator or there are multiple arcs, and whether the arc(s) are isochronous or non-isochronous.

  2. Overexpression of insulin-like growth factor-1 attenuates skeletal muscle damage and accelerates muscle regeneration and functional recovery after disuse.

    Science.gov (United States)

    Ye, Fan; Mathur, Sunita; Liu, Min; Borst, Stephen E; Walter, Glenn A; Sweeney, H Lee; Vandenborne, Krista

    2013-05-01

    Skeletal muscle is a highly dynamic tissue that responds to endogenous and external stimuli, including alterations in mechanical loading and growth factors. In particular, the antigravity soleus muscle experiences significant muscle atrophy during disuse and extensive muscle damage upon reloading. Given that insulin-like growth factor-1 (IGF-1) has been implicated as a central regulator of muscle repair and modulation of muscle size, we examined the effect of virally mediated overexpression of IGF-1 on the soleus muscle following hindlimb cast immobilization and upon reloading. Recombinant IGF-1 cDNA virus was injected into one of the posterior hindlimbs of the mice, while the contralateral limb was injected with saline (control). At 20 weeks of age, both hindlimbs were immobilized for 2 weeks to induce muscle atrophy in the soleus and ankle plantarflexor muscle group. Subsequently, the mice were allowed to reambulate, and muscle damage and recovery were monitored over a period of 2-21 days. The primary finding of this study was that IGF-1 overexpression attenuated reloading-induced muscle damage in the soleus muscle, and accelerated muscle regeneration and force recovery. Muscle T2 assessed by magnetic resonance imaging, a non-specific marker of muscle damage, was significantly lower in IGF-1-injected compared with contralateral soleus muscles at 2 and 5 days reambulation (Pmuscle damage in IGF-1-injected soleus muscles was confirmed on histology, with a lower fractional area of abnormal muscle tissue in IGF-1-injected muscles at 2 days reambulation (33.2±3.3 versus 54.1±3.6%, Pmuscle regeneration included timely increases in the number of central nuclei (21% at 5 days reambulation), paired-box transcription factor 7 (36% at 5 days), embryonic myosin (37% at 10 days) and elevated MyoD mRNA (7-fold at 2 days) in IGF-1-injected limbs (Pmuscles from damage and accelerating muscle repair and regeneration.

  3. Growth factor-activated stem cell circuits and stromal signals cooperatively accelerate non-integrated iPSC reprogramming of human myeloid progenitors.

    Directory of Open Access Journals (Sweden)

    Tea Soon Park

    Full Text Available Nonviral conversion of skin or blood cells into clinically useful human induced pluripotent stem cells (hiPSC occurs in only rare fractions (~0.001%-0.5% of donor cells transfected with non-integrating reprogramming factors. Pluripotency induction of developmentally immature stem-progenitors is generally more efficient than differentiated somatic cell targets. However, the nature of augmented progenitor reprogramming remains obscure, and its potential has not been fully explored for improving the extremely slow pace of non-integrated reprogramming. Here, we report highly optimized four-factor reprogramming of lineage-committed cord blood (CB myeloid progenitors with bulk efficiencies of ~50% in purified episome-expressing cells. Lineage-committed CD33(+CD45(+CD34(- myeloid cells and not primitive hematopoietic stem-progenitors were the main targets of a rapid and nearly complete non-integrated reprogramming. The efficient conversion of mature myeloid populations into NANOG(+TRA-1-81(+ hiPSC was mediated by synergies between hematopoietic growth factor (GF, stromal activation signals, and episomal Yamanaka factor expression. Using a modular bioinformatics approach, we demonstrated that efficient myeloid reprogramming correlated not to increased proliferation or endogenous Core factor expressions, but to poised expression of GF-activated transcriptional circuits that commonly regulate plasticity in both hematopoietic progenitors and embryonic stem cells (ESC. Factor-driven conversion of myeloid progenitors to a high-fidelity pluripotent state was further accelerated by soluble and contact-dependent stromal signals that included an implied and unexpected role for Toll receptor-NFκB signaling. These data provide a paradigm for understanding the augmented reprogramming capacity of somatic progenitors, and reveal that efficient induced pluripotency in other cell types may also require extrinsic activation of a molecular framework that commonly

  4. Temporal adaptation of neutrophil oxidative responsiveness to n-formyl-methionyl-leucyl-phenylalanine. Acceleration by granulocyte-macrophage colony stimulating factor.

    Science.gov (United States)

    English, D; Broxmeyer, H E; Gabig, T G; Akard, L P; Williams, D E; Hoffman, R

    1988-10-01

    This investigation was undertaken to clarify the mechanism by which purified recombinant human granulocyte-macrophage colony stimulating factor (GM-CSF) potentiates neutrophil oxidative responses triggered by the chemotactic peptide, FMLP. Previous studies have shown that GM-CSF priming of neutrophil responses to FMLP is induced relatively slowly, requiring 90 to 120 min of incubation in vitro, is not associated with increased levels of cytoplasmic free Ca2+, but is associated with up-regulation of cell-surface FMLP receptors. We have confirmed these findings and further characterized the process of GM-CSF priming. We found that the effect of GM-CSF on neutrophil oxidative responsiveness was induced in a temperature-dependent manner and was not reversed when the cells were washed extensively to remove the growth factor before stimulation with FMLP. Extracellular Ca2+ was not required for functional enhancement by GM-CSF and GM-CSF alone effected no detectable alteration in the 32P-labeled phospholipid content of neutrophils during incubation in vitro. Our data indicate that GM-CSF exerts its influence on neutrophils by accelerating a process that occurs spontaneously and results in up-regulation of both cell-surface FMLP receptors and oxidative responsiveness to FMLP. Thus, the results demonstrate that, with respect to oxidative activation, circulating endstage polymorphonuclear leukocytes are nonresponsive or hyporesponsive to FMLP; functional responsiveness increases dramatically as surface FMLP receptors are gradually deployed after the cells leave the circulation. Thus, as neutrophils mature, their responsiveness to FMLP changes in a manner which may be crucial for efficient host defense. At 37 degrees C, this process is markedly potentiated by GM-CSF. We conclude that endogenous GM-CSF, released systemically or at sites of infection and inflammation, potentially plays an important role in host defense by accelerating functional maturation of responding

  5. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  6. Monitor backscatter factors for the Varian 21EX and TrueBeam linear accelerators: measurements and Monte Carlo modelling.

    Science.gov (United States)

    Zavgorodni, Sergei; Alhakeem, Eyad; Townson, Reid

    2014-02-21

    Linac backscattered radiation (BSR) into the monitor chamber affects the chamber's signal and has to be accounted for in radiotherapy dose calculations. In Monte Carlo (MC) calculations, the BSR can be modelled explicitly and accounted for in absolute dose. However, explicit modelling of the BSR becomes impossible if treatment head geometry is not available. In this study, monitor backscatter factors (MBSFs), defined as the ratio of the charge collected in the monitor chamber for a reference field to that of a given field, have been evaluated experimentally and incorporated into MC modelling of linacs with either known or unknown treatment head geometry. A telescopic technique similar to that by Kubo (1989 Med. Phys. 16 295-98) was used. However, instead of lead slits, a 1.8 mm diameter collimator and a small (2 mm diameter) detector positioned at extended source to detector distance were used. This setup provided a field of view to the source of less than 3.1 mm and allowed for MBSF measurements of open fields from 1 × 1 to 40 × 40 cm(2). For the fields with both X and Y dimensions exceeding 15 cm, a diode detector was used. A pinpoint ionization chamber was used for smaller fields. MBSFs were also explicitly modelled in MC calculations using BEAMnrc and DOSXYZnrc codes for 6 and 18 MV beams of a Varian 21EX linac. A method for deriving the D(ch)(forward) values that are used in MC absolute dose calculations was demonstrated. These values were derived from measured MBSFs for two 21EX and four TrueBeam energies. MBSFs were measured for 6 and 18 MV beams from Varian 21EX, and for 6 MV, 10 MV-FFF, 10 MV, and 15 MV beams from Varian TrueBeam linacs. For the open field sizes modelled in this study for the 21EX, the measured MBSFs agreed with MC calculated values within combined statistical (0.4%) and experimental (0.2%) uncertainties. Variation of MBSFs across field sizes was about a factor of two smaller for the TrueBeam compared to 21EX Varian linacs. Measured

  7. Tranexamic acid combined with recombinant factor VIII increases clot resistance to accelerated fibrinolysis in severe hemophilia A

    DEFF Research Database (Denmark)

    Hvas, Anne-Mette; Sørensen, Hanne Thykjær; Norengaard, Lisbeth

    2007-01-01

    BACKGROUND: Most patients with severe hemophilia A suffer from a profoundly compromised hemostatic response. In addition to both the delayed and slow development of a clot, previous studies have documented that severe hemophilia A is also associated with reduced clot stability. OBJECTIVES: We...... examined whether the clot stability in hemophiliacs could be improved by treatment with tranexamic acid (TXA) in combination with recombinant factor VIII (rFVIII). PATIENTS/METHODS: Baseline blood samples were obtained from eight males with severe hemophilia A. Thereafter, a bolus injection of r...... the elasticity curve increased 5-fold after rFVIII and 24-fold after addition of TXA. CONCLUSIONS: The study demonstrates that simultaneous treatment with TXA and rFVIII significantly improves the clot stability in patients with hemophilia A. Udgivelsesdato: December...

  8. Separable projection integrals for higher-order correlators of the cosmic microwave sky: Acceleration by factors exceeding 100

    Science.gov (United States)

    Briggs, J. P.; Pennycook, S. J.; Fergusson, J. R.; Jäykkä, J.; Shellard, E. P. S.

    2016-04-01

    We present a case study describing efforts to optimise and modernise "Modal", the simulation and analysis pipeline used by the Planck satellite experiment for constraining general non-Gaussian models of the early universe via the bispectrum (or three-point correlator) of the cosmic microwave background radiation. We focus on one particular element of the code: the projection of bispectra from the end of inflation to the spherical shell at decoupling, which defines the CMB we observe today. This code involves a three-dimensional inner product between two functions, one of which requires an integral, on a non-rectangular domain containing a sparse grid. We show that by employing separable methods this calculation can be reduced to a one-dimensional summation plus two integrations, reducing the overall dimensionality from four to three. The introduction of separable functions also solves the issue of the non-rectangular sparse grid. This separable method can become unstable in certain scenarios and so the slower non-separable integral must be calculated instead. We present a discussion of the optimisation of both approaches. We demonstrate significant speed-ups of ≈100×, arising from a combination of algorithmic improvements and architecture-aware optimisations targeted at improving thread and vectorisation behaviour. The resulting MPI/OpenMP hybrid code is capable of executing on clusters containing processors and/or coprocessors, with strong-scaling efficiency of 98.6% on up to 16 nodes. We find that a single coprocessor outperforms two processor sockets by a factor of 1.3× and that running the same code across a combination of both microarchitectures improves performance-per-node by a factor of 3.38×. By making bispectrum calculations competitive with those for the power spectrum (or two-point correlator) we are now able to consider joint analysis for cosmological science exploitation of new data.

  9. Monitor backscatter factors for the Varian 21EX and TrueBeam linear accelerators: measurements and Monte Carlo modeling

    CERN Document Server

    Zavgorodni, Sergei; Townson, Reid

    2013-01-01

    Objectives: Linac backscattered radiation (BSR) into the monitor chamber affects the chamber signal and has to be accounted for in radiotherapy dose calculations. In Monte Carlo (MC) calculations BSR can be modeled explicitly and incorporated into absolute dose. However, explicit modeling of BSR becomes impossible if treatment head geometry is not available. In this study, monitor backscatter factors (MBSFs), defined as the ratio of the charge collected in the monitor chamber for a reference field to that of a given field, have been evaluated experimentally and incorporated into MC modeling. Materials and methods: A telescopic technique similar to that by Kubo (1989) was used. However, instead of lead slits, a 1.8 mm diameter collimator and a PTW pinpoint ionization chamber positioned at extended SDD were used. These provided a field of view to the source of less than 3.1 mm. MBSFs were also explicitly modeled in MC calculations using BEAMnrc and DOSXYZnrc codes for 6MV and 18MV beams of a Varian 21EX linac, ...

  10. Angiopoietin-like protein 2 increases renal fibrosis by accelerating transforming growth factor-β signaling in chronic kidney disease.

    Science.gov (United States)

    Morinaga, Jun; Kadomatsu, Tsuyoshi; Miyata, Keishi; Endo, Motoyoshi; Terada, Kazutoyo; Tian, Zhe; Sugizaki, Taichi; Tanigawa, Hiroki; Zhao, Jiabin; Zhu, Shunshun; Sato, Michio; Araki, Kimi; Iyama, Ken-ichi; Tomita, Kengo; Mukoyama, Masashi; Tomita, Kimio; Kitamura, Kenichiro; Oike, Yuichi

    2016-02-01

    Renal fibrosis is a common pathological consequence of chronic kidney disease (CKD) with tissue fibrosis closely associated with chronic inflammation in numerous pathologies. However, molecular mechanisms underlying that association, particularly in the kidney, remain unclear. Here, we determine whether there is a molecular link between chronic inflammation and tissue fibrosis in CKD progression. Histological analysis of human kidneys indicated abundant expression of angiopoietin-like protein 2 (ANGPTL2) in renal tubule epithelial cells during progression of renal fibrosis. Numerous ANGPTL2-positive renal tubule epithelial cells colocalized with cells positive for transforming growth factor (TGF)-β1, a critical mediator of tissue fibrosis. Analysis of M1 collecting duct cells in culture showed that TGF-β1 increases ANGPTL2 expression by attenuating its repression through microRNA-221. Conversely, ANGPTL2 increased TGF-β1 expression through α5β1 integrin-mediated activation of extracellular signal-regulated kinase. Furthermore, ANGPTL2 deficiency in a mouse unilateral ureteral obstruction model significantly reduced renal fibrosis by decreasing TGF-β1 signal amplification in kidney. Thus, ANGPTL2 and TGF-β1 positively regulate each other as renal fibrosis progresses. Our study provides insight into molecular mechanisms underlying chronic inflammation and tissue fibrosis and identifies potential therapeutic targets for CKD treatment.

  11. A mutein of human basic fibroblast growth factor TGP-580 accelerates colonic ulcer healing by stimulating angiogenesis in the ulcer bed in rats.

    Science.gov (United States)

    Satoh, H; Szabo, S

    2015-10-01

    Previously, we reported that TGP-580, a mutein of human basic fibroblast growth factor (bFGF), accelerated the healing of gastric and duodenal ulcers in rats. In the present study, we examined the effect of TGP-580 on the healing of colonic ulcers. In male Sprague Dawley rats, ulcers were induced in the colon 6 cm from the anus by enema of 50 μl of 3% N-ethylmaleimide, a sulfhydryl alkylator. The lesions were examined under a dissecting microscope (x10). The concentration of bFGF in the ulcerated colon was measured by enzyme immunoassay, and both the distribution of bFGF and the density of microvessels in the ulcer bed were examined by immunohistochemical staining. The content of bFGF in the ulcerated colon was markedly increased associated with ulcer healing, and ulcer healing was significantly delayed by intravenous administration of a monoclonal antibody for bFGF (MAb 3H3) once daily for 10 days. In the ulcer bed, many cells such as fibroblasts, vascular endothelial cells and macrophages were positively stained with bFGF antiserum. TGP-580, human bFGF or dexamethasone was given intracolonally twice daily for 10 days, starting the day after ulcer induction. TGP-580 (0.2 - 20 μg/ml, 200 μl/rat) dose-dependently accelerated ulcer healing, and its effect was more than 10 times stronger than that of human bFGF. Density (μm/0.01 mm(2)) of microvessels in the ulcer bed was significantly increased by treatment with TGP-580, and there was a good correlation between the density of microvessels and the decrease of ulcerated area (R(2) = 0.633). On the other hand dexamethasone (20 μg/ml) inhibited angiogenesis in the ulcer bed and delayed ulcer healing. These results suggest that angiogenesis in the ulcer bed plays an important role in ulcer healing, and that bFGF mutein TGP-580 accelerated colonic ulcer healing, at least in part, by stimulating angiogenesis, whereas glucocorticoids may delay the healing by inhibiting angiogenesis.

  12. Hepatocyte Growth Factor Effects on Mesenchymal Stem Cells Derived from Human Arteries: A Novel Strategy to Accelerate Vascular Ulcer Wound Healing

    Directory of Open Access Journals (Sweden)

    Sabrina Valente

    2016-01-01

    Full Text Available Vascular ulcers are a serious complication of peripheral vascular disease, especially in diabetics. Several approaches to treat the wounds are proposed but they show poor outcomes and require long healing times. Hepatocyte Growth Factor/Scatter Factor (HGF/SF is a pleiotropic cytokine exerting many biological activities through the c-Met receptor. This study was aimed at verifying whether HGF/SF influences proliferation, migration, and angiogenesis on mesenchymal stem cells isolated from human arteries (hVW-MSCs. hVW-MSCs were exposed to NIBSC HGF/SF (2.5, 5, 10, and 70 ng/mL from 6 hrs to 7 days. HGF and c-MET mRNA and protein expression, cell proliferation (Alamar Blue and Ki–67 assay, migration (scratch and transwell assays, and angiogenesis (Matrigel were investigated. hVW-MSCs displayed stemness features and expressed HGF and c-MET. HGF/SF did not increase hVW-MSC proliferation, whereas it enhanced the cell migration, the formation of capillary-like structures, and the expression of angiogenic markers (vWF, CD31, and KDR. The HGF/SF effects on hVW-MSC migration and angiogenic potential are of great interest to accelerate wound healing process. Local delivery of HGF/SF could therefore improve the healing of unresponsive vascular ulcers.

  13. Hepatocyte Growth Factor Effects on Mesenchymal Stem Cells Derived from Human Arteries: A Novel Strategy to Accelerate Vascular Ulcer Wound Healing.

    Science.gov (United States)

    Valente, Sabrina; Ciavarella, Carmen; Pasanisi, Emanuela; Ricci, Francesca; Stella, Andrea; Pasquinelli, Gianandrea

    2016-01-01

    Vascular ulcers are a serious complication of peripheral vascular disease, especially in diabetics. Several approaches to treat the wounds are proposed but they show poor outcomes and require long healing times. Hepatocyte Growth Factor/Scatter Factor (HGF/SF) is a pleiotropic cytokine exerting many biological activities through the c-Met receptor. This study was aimed at verifying whether HGF/SF influences proliferation, migration, and angiogenesis on mesenchymal stem cells isolated from human arteries (hVW-MSCs). hVW-MSCs were exposed to NIBSC HGF/SF (2.5, 5, 10, and 70 ng/mL) from 6 hrs to 7 days. HGF and c-MET mRNA and protein expression, cell proliferation (Alamar Blue and Ki-67 assay), migration (scratch and transwell assays), and angiogenesis (Matrigel) were investigated. hVW-MSCs displayed stemness features and expressed HGF and c-MET. HGF/SF did not increase hVW-MSC proliferation, whereas it enhanced the cell migration, the formation of capillary-like structures, and the expression of angiogenic markers (vWF, CD31, and KDR). The HGF/SF effects on hVW-MSC migration and angiogenic potential are of great interest to accelerate wound healing process. Local delivery of HGF/SF could therefore improve the healing of unresponsive vascular ulcers.

  14. 不完全非负矩阵分解的加速算法%Accelerated Algorithm to Incomplete Nonnegative Matrix Factorization

    Institute of Scientific and Technical Information of China (English)

    史加荣; 焦李成; 尚凡华

    2011-01-01

    非负矩阵分解(NMF)已成为数据分析与处理的一种日益流行的方法.当数据矩阵不完全时,可用加权非负矩阵分解(WNMF)来分解矩阵.但是在WNMF算法中,对于给定的搜索方向,步长的选取一般来说不是最优的.本文研究了不完全非负矩阵分解(INMF)问题,提出了加速算法(AINMF).首先,将INMF问题转化为交替地求解两个非负最小二乘(NNNLS)问题.对于每个NNLS问题,在搜索方向上采用精确的步长.接着,分析了NNLS问题的算法复杂度.最后,试验结果证实了AINMF优于WNMF.%Nornegative matrix factorization (NMF) is an increasingly popular technique for data processing and analysis. For an incomplete data matrix, the weighted nonnegative matrix factorization (WNMF) is employed to decompose it. But the searching step size in WNMF is not optimal along the given seaching direction. This paper studies the incomplete nonnegative matrix factorization (INMF) and proposes an accelerated algorithm. First, INMF is transformed into solving alternatively two nonnegative least squares (NNLS) problems. For each NNLS problem, the exact step size is chosen along the searching direction. Then, the complexity of NNLS problems is analyzed. Finally, experimental results show that the proposed method outperforms WNMF.

  15. Accelerated Unification

    OpenAIRE

    Arkani-Hamed, Nima; Cohen, Andrew; Georgi, Howard

    2001-01-01

    We construct four dimensional gauge theories in which the successful supersymmetric unification of gauge couplings is preserved but accelerated by N-fold replication of the MSSM gauge and Higgs structure. This results in a low unification scale of $10^{13/N}$ TeV.

  16. Developing a framework for predicting upper extremity muscle activities, postures, velocities, and accelerations during computer use: the effect of keyboard use, mouse use, and individual factors on physical exposures.

    Science.gov (United States)

    Bruno Garza, Jennifer L; Catalano, Paul J; Katz, Jeffrey N; Huysmans, Maaike A; Dennerlein, Jack T

    2012-01-01

    Prediction models were developed based on keyboard and mouse use in combination with individual factors that could be used to predict median upper extremity muscle activities, postures, velocities, and accelerations experienced during computer use. In the laboratory, 25 participants performed five simulated computer trials with different amounts of keyboard and mouse use ranging from a highly keyboard-intensive trial to a highly mouse-intensive trial. During each trial, muscle activity and postures of the shoulder and wrist and velocities and accelerations of the wrists, along with percentage keyboard and mouse use, were measured. Four individual factors (hand length, shoulder width, age, and gender) were also measured on the day of data collection. Percentage keyboard and mouse use explained a large amount of the variability in wrist velocities and accelerations. Although hand length, shoulder width, and age were each significant predictors of at least one median muscle activity, posture, velocity, or acceleration exposure, these individual factors explained very little variability in addition to percentage keyboard and mouse use in any of the physical exposures investigated. The amounts of variability explained for models predicting median wrist velocities and accelerations ranged from 75 to 84% but were much lower for median muscle activities and postures (0-50%). RMS errors ranged between 8 to 13% of the range observed. While the predictions for wrist velocities and accelerations may be able to be used to improve exposure assessment for future epidemiologic studies, more research is needed to identify other factors that may improve the predictions for muscle activities and postures.

  17. Small fields output factors measurements and correction factors determination for several detectors for a CyberKnife{sup Registered-Sign} and linear accelerators equipped with microMLC and circular cones

    Energy Technology Data Exchange (ETDEWEB)

    Bassinet, C.; Huet, C.; Derreumaux, S.; Baumann, M.; Trompier, F.; Roch, P.; Clairand, I. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP17, 92262 Fontenay-aux-Roses Cedex (France); Brunet, G.; Gaudaire-Josset, S. [Institut de Cancerologie de l' Ouest Rene Gauducheau, bd Jacques Monod, 44805 Saint Herblain Cedex (France); Chea, M.; Boisserie, G. [Groupe Hospitalier Pitie-Salpetriere, 47/83 bd de l' Hopital, 75651 Paris Cedex 13 (France); Lacornerie, T. [Centre Oscar Lambret, 3, rue Frederic Combemale, BP 307, 59020 Lille Cedex (France)

    2013-07-15

    Purpose: The use of small photon fields is now an established practice in stereotactic radiosurgery and radiotherapy. However, due to a lack of lateral electron equilibrium and high dose gradients, it is difficult to accurately measure the dosimetric quantities required for the commissioning of such systems. Moreover, there is still no metrological dosimetric reference for this kind of beam today. In this context, the first objective of this work was to determine and to compare small fields output factors (OF) measured with different types of active detectors and passive dosimeters for three types of facilities: a CyberKnife{sup Registered-Sign} system, a dedicated medical linear accelerator (Novalis) equipped with m3 microMLC and circular cones, and an adaptive medical linear accelerator (Clinac 2100) equipped with an additional m3 microMLC. The second one was to determine the k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}} correction factors introduced in a recently proposed small field dosimetry formalism for different active detectors.Methods: Small field sizes were defined either by microMLC down to 6 Multiplication-Sign 6 mm{sup 2} or by circular cones down to 4 mm in diameter. OF measurements were performed with several commercially available active detectors dedicated to measurements in small fields (high resolution diodes: IBA SFD, Sun Nuclear EDGE, PTW 60016, PTW 60017; ionizing chambers: PTW 31014 PinPoint chamber, PTW 31018 microLion liquid chamber, and PTW 60003 natural diamond). Two types of passive dosimeters were used: LiF microcubes and EBT2 radiochromic films.Results: Significant differences between the results obtained by several dosimetric systems were observed, particularly for the smallest field size for which the difference in the measured OF reaches more than 20%. For passive dosimeters, an excellent agreement was observed (better than 2%) between EBT2 and LiF microcubes

  18. A decay-accelerating factor-binding strain of coxsackievirus B3 requires the coxsackievirus-adenovirus receptor protein to mediate lytic infection of rhabdomyosarcoma cells.

    Science.gov (United States)

    Shafren, D R; Williams, D T; Barry, R D

    1997-12-01

    The composition of the cellular receptor complex for coxsackievirus B3 (CVB3) has been an area of much contention for the last 30 years. Recently, two individual components of a putative CVB3 cellular receptor complex have been identified as (i) decay-accelerating factor (DAF) and (ii) the coxsackievirus-adenovirus receptor protein (CAR). The present study elucidates the individual roles of DAF and CAR in cell entry of CVB3 Nancy. First, we confirm that the DAF-binding phenotype of CVB3 correlates to the presence of key amino acids located in the viral capsid protein, VP2. Second, using antibody blockade, we show that complete protection of permissive cells from infection by high input multiplicities of CVB3 requires a combination of both anti-DAF and anti-CAR antibodies. Finally, it is shown that expression of the CAR protein on the surface of nonpermissive DAF-expressing RD cells renders them highly susceptible to CVB3-mediated lytic infection. Therefore, although the majority of CVB3 Nancy attaches to the cell via DAF, only virus directly interacting with the CAR protein mediates lytic infection. The role of DAF in CVB3 cell infection may be analogous to that recently described for coxsackievirus A21 (D. R. Shafren, D. J. Dorahy, R. A. Ingham, G. F. Burns, and R. D. Barry, J. Virol. 71:4736-4743, 1997), in that DAF may act as a CVB3 sequestration site, enhancing viral presentation to the functional CAR protein.

  19. Evaluating and modeling the effects of surface sampling factors on the recovery of organic chemical attribution signatures using the accelerated diffusion sampler and solvent extraction.

    Science.gov (United States)

    Mo, Kai-For; Heredia-Langner, Alejandro; Fraga, Carlos G

    2017-03-01

    In this study, an experimental design matrix was created and executed to test the effects of various real-world factors on the ability of (1) the accelerated diffusion sampler with solid phase micro-extraction (ADS-SPME) and (2) solvent extraction to capture organic chemical attribution signatures (CAS) from dimethyl methylphosphonate (DMMP) spiked onto painted wall board (PWB) surfaces. The DMMP CAS organic impurities sampled by ADS-SPME and solvent extraction were analyzed by gas chromatography/mass spectrometry (GC/MS). The number of detected DMMP CAS impurities and their respective GC/MS peak areas were determined as a function of DMMP stock, DMMP spiked volume, exposure time, SPME sampling time, and ADS headspace pressure. Based on the statistical analysis of experimental results, several general conclusions are made: (1) the amount of CAS impurity detected using ADS-SPME and GC/MS was most influenced by spiked volume, stock, and ADS headspace pressure, (2) reduced ADS headspace pressure increased the amount of detected CAS impurity, as measured by GC/MS peak area, by up to a factor of 1.7-1.9 compared to ADS at ambient headspace pressure, (3) the ADS had no measurable effect on the number of detected DMMP impurities, that is, ADS (with and without reduced pressure) had no practical effect on the DMMP impurity profile collected from spiked PWB, and (4) solvent extraction out performed ADS-SPME in terms of consistently capturing all or most of the targeted DMMP impurities from spiked PWB.

  20. Evaluating and modeling the effects of surface sampling factors on the recovery of organic chemical attribution signatures using the accelerated diffusion sampler and solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Kai-For; Heredia-Langner, Alejandro; Fraga, Carlos G.

    2017-03-01

    In this study, an experimental design matrix was created and executed in order to test the effects of various real-world factors on the ability of the (1) accelerated diffusion sampler with solid phase micro-extraction (ADS-SPME) and (2) solvent extraction to capture organic chemical attribution signatures (CAS) from dimethyl methylphosphonate (DMMP) spiked onto painted wall board (PWB) surfaces. The DMMP CAS organic impurities sampled by ADS-SPME and solvent extraction were analyzed by gas chromatography/mass spectrometry (GC/MS). The number of detected DMMP CAS impurities and their respective GC/MS peak areas were determined as a function of DMMP stock, DMMP spiked volume, exposure time, SPME sampling time, and ADS headspace pressure. Based on the statistical analysis of experimental results, several general conclusions are made: (1) ADS-SPME with vacuum (i.e., reduced pressure) increased the amount of detected CAS impurity, as measured by GC/MS peak area, by a factor of 1.7 to 1.9 for PWB under certain experimental conditions, (2) the amount of detected CAS impurity was most influenced by spiked volume, stock, and ADS headspace pressure, (3) the ADS had no measurable effect on the number of detected DMMP impurities, that is, the ADS (with and without reduced pressure) had no practical effect on the DMMP impurity profile collected from spiked PWB, and (4) solvent extraction out performed ADS-SPME in terms of consistently capturing all or most of the targeted DMMP impurities from spiked PWB.

  1. Particle Accelerators in China

    Science.gov (United States)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  2. MUON ACCELERATION

    Energy Technology Data Exchange (ETDEWEB)

    BERG,S.J.

    2003-11-18

    One of the major motivations driving recent interest in FFAGs is their use for the cost-effective acceleration of muons. This paper summarizes the progress in this area that was achieved leading up to and at the FFAG workshop at KEK from July 7-12, 2003. Much of the relevant background and references are also given here, to give a context to the progress we have made.

  3. Laser acceleration

    Science.gov (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  4. Accelerators and the Accelerator Community

    Energy Technology Data Exchange (ETDEWEB)

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  5. accelerating cavity

    CERN Multimedia

    On the inside of the cavitytThere is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  6. Accelerator applications in energy and security

    CERN Document Server

    Chou, Weiren

    2015-01-01

    As accelerator science and technology progressed over the past several decades, the accelerators themselves have undergone major improvements in multiple performance factors: beam energy, beam power, and beam brightness. As a consequence, accelerators have found applications in a wide range of fields in our life and in our society. The current volume is dedicated to applications in energy and security, two of the most important and urgent topics in today's world. This volume makes an effort to provide a review as complete and up to date as possible of this broad and challenging subject. It contains overviews on each of the two topics and a series of articles for in-depth discussions including heavy ion accelerator driven inertial fusion, linear accelerator-based ADS systems, circular accelerator-based ADS systems, accelerator-reactor interface, accelerators for fusion material testing, cargo inspection, proton radiography, compact neutron generators and detectors. It also has a review article on accelerator ...

  7. 多因素综合海洋气候自然加速试验技术相关性和加速性验证%Relativity and Acceleration Verification of Multi-factors Integrated Marine Climate Natural Accelerated Test Technologies

    Institute of Scientific and Technical Information of China (English)

    彭京川; 郭赞洪; 杨晓然

    2016-01-01

    Objective To verify the relativity and acceleration of multi-factors integrated marine climate natural accelerated test technologies to outdoor exposure test in tropic marine climate.Methods Multi-factors integrated marine climate natural ac-celerated test device, relative enterprise standards as well as traditional marine climate outdoor exposure were adopted to test and verify automobile fasteners of different surface treatment technologies, standard metals, organic coatings and plastics as specimen. Spearman order relativity coefficient method and acceleration factor method were used to further verify the relativity and acceleration.Results Automobile fasteners, standard metals and organic coatings indicated that their corrosion failure mod-es were the same in multi-factors integrated marine climate natural accelerated test and tropic marine climate outdoor exposure test. For the accelerated test to outdoor exposure test in the exposure site 350 meters from South China Sea, order relativity coefficient of fasteners was 1, and the acceleration rate of zinc nickel alloy plated fastener, chromium free zinc aluminum alloy coated fastener, LAFRE coated fastener and Graphene coated fastener was 7.7, 11.3, 10.3 and 13.5 respectively; order relativity coefficient of standard metals was 0.8, and the acceleration rate of Q235, industrial pure aluminum, industrial pure zinc, and in-dustrial pure copper was 11.8,11.5,9.3 and 3.7 respectively. For the accelerated test to outdoor exposure test in the marine plat-form, order relativity coefficient of standard metals was 1, and the acceleration rate of Q235, industrial pure aluminum, industri-al pure zinc, and industrial pure copper was 3.4, 2.1, 4.5 and 2.2 respectively.Conclusion Multi-factors integrated marine cli-mate natural accelerated test technology has good relativity to tropic marine climate outdoor exposure, and has better relativity to marine platform exposure. The technology also has high acceleration rate to

  8. TEACHERS IN THE ERA OF ACCELERATION : How the acceleration of ICT developments influences the ICT use by teachers at school

    OpenAIRE

    Charalambous, Georgios

    2015-01-01

    In the effort to examine the factors that impact the use of ICT by teachers, research has up until now neglected the acceleration of ICT developments as a factor that affects the successful integration of ICT in education. The technological acceleration in general has triggered significant changes at the social level, such as the acceleration of social change and the acceleration of the pace of life. This is why the study of the acceleration of ICT provides for a good theoretical framework to...

  9. Social-emotional characteristics of gifted accelerated and non-accelerated students in the Netherlands

    NARCIS (Netherlands)

    Hoogeveen, A.J.M.; Hell, J.G. van; Verhoeven, L.T.W.

    2012-01-01

    Background. In the studies of acceleration conducted so far a multidimensional perspective has largely been neglected. No attempt has been made to relate social-emotional characteristics of accelerated versus non-accelerated students in perspective of environmental factors. Aims. In this study, soci

  10. Social-Emotional Characteristics of Gifted Accelerated and Non-Accelerated Students in the Netherlands

    Science.gov (United States)

    Hoogeveen, Lianne; van Hell, Janet G.; Verhoeven, Ludo

    2012-01-01

    Background: In the studies of acceleration conducted so far a multidimensional perspective has largely been neglected. No attempt has been made to relate social-emotional characteristics of accelerated versus non-accelerated students in perspective of environmental factors. Aims: In this study, social-emotional characteristics of accelerated…

  11. Performance analysis of acceleration resolution for radar signal

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Hongzhong; (赵宏钟); FU; Qiang; (付; 强)

    2003-01-01

    The high acceleration of moving targets has brought severe problems in radar signal processing, such as the decrease in output signal-noise-ratio and the deterioration of Doppler resolution. This paper presents an acceleration ambiguity function (AAF) for characterizing the acceleration effects and the acceleration resolution property in radar signal processing. The definition of the acceleration resolution based on AAF is also presented. Using AAF as an analyzing tool, some factors are derived including the loss factor of output SNR, the broadening factor of Doppler resolution, and the optimal accumulative time (OPT) caused by acceleration in linear-phase matched filtering. The convergent property of quadratic-phase matched-filter for searching for and estimating the acceleration is discussed. The results and conclusions are helpful for the quantitative analysis of the acceleration effects on signal processing, and for evaluation of the performance of acceleration in radar signal waveform design.

  12. 2014 CERN Accelerator Schools: Plasma Wake Acceleration

    CERN Multimedia

    2014-01-01

    A specialised school on Plasma Wake Acceleration will be held at CERN, Switzerland from 23-29 November, 2014.   This course will be of interest to staff and students in accelerator laboratories, university departments and companies working in or having an interest in the field of new acceleration techniques. Following introductory lectures on plasma and laser physics, the course will cover the different components of a plasma wake accelerator and plasma beam systems. An overview of the experimental studies, diagnostic tools and state of the art wake acceleration facilities, both present and planned, will complement the theoretical part. Topical seminars and a visit of CERN will complete the programme. Further information can be found at: http://cas.web.cern.ch/cas/PlasmaWake2014/CERN-advert.html http://indico.cern.ch/event/285444/

  13. Application of acceleration factor in reliability assessment of product in varying stresses%加速系数在产品变应力可靠性评估中的应用

    Institute of Scientific and Technical Information of China (English)

    赵志草; 宋保维; 王新平; 梁庆卫

    2012-01-01

    针对产品可靠性评估中忽视使用应力变化的问题,基于加速寿命试验的思想,利用加速系数,在已知加速模型的基础上建立了处理变化使用应力的时间折合模型及变化的使用应力在某个时间段内的等效应力模型.最后将上述模型应用到了某型舰船电缆绝缘材料的等效使用环境温度计算中.通过与原方法对比,验证了文中方法的正确性及有效性.该方法对产品其他情况下变应力的处理有借鉴作用.%For the neglect of changes of operating stress in re-liability assessment of product, based on the thought of accelerated life tests and the known acceleration model, the equivalent time model to deal with the varying operating stress and the equivalent stress model of operating stress during a period of time were given by using the acceleration factor. Then, the equivalent stress model was applied to the calculation of equivalent operating environmental temperature for some ship cable insulation. Comparing with former method, the result shows the validity of method mentioned above. This method can also be the reference of equivalent stress process-ing in other cases.

  14. Improved plasma accelerator

    Science.gov (United States)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  15. Accelerator Technology Division

    Science.gov (United States)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  16. High Energy Particle Accelerators

    CERN Multimedia

    Audio Productions, Inc, New York

    1960-01-01

    Film about the different particle accelerators in the US. Nuclear research in the US has developed into a broad and well-balanced program.Tour of accelerator installations, accelerator development work now in progress and a number of typical experiments with high energy particles. Brookhaven, Cosmotron. Univ. Calif. Berkeley, Bevatron. Anti-proton experiment. Negative k meson experiment. Bubble chambers. A section on an electron accelerator. Projection of new accelerators. Princeton/Penn. build proton synchrotron. Argonne National Lab. Brookhaven, PS construction. Cambridge Electron Accelerator; Harvard/MIT. SLAC studying a linear accelerator. Other research at Madison, Wisconsin, Fixed Field Alternate Gradient Focusing. (FFAG) Oakridge, Tenn., cyclotron. Two-beam machine. Comments : Interesting overview of high energy particle accelerators installations in the US in these early years. .

  17. Accelerators, Colliders, and Snakes

    Science.gov (United States)

    Courant, Ernest D.

    2003-12-01

    The author traces his involvement in the evolution of particle accelerators over the past 50 years. He participated in building the first billion-volt accelerator, the Brookhaven Cosmotron, which led to the introduction of the "strong-focusing" method that has in turn led to the very large accelerators and colliders of the present day. The problems of acceleration of spin-polarized protons are also addressed, with discussions of depolarizing resonances and "Siberian snakes" as a technique for mitigating these resonances.

  18. Factors influencing flow accelerated corrosion in air cooling condensers%直接空冷凝汽器流动加速腐蚀的影响因素

    Institute of Scientific and Technical Information of China (English)

    孟龙; 杨静; 孙本达; 张祥金; 祁东东; 倪瑞涛

    2014-01-01

    By using the orthogonal test method,effects of dissolved oxygen content,pH value,different types of alkaline agent,and flow velocity on carbon steel flow accelerated corrosion (FAC)were discussed, under air cooling island working condition.Studies show that temperature has the largest influence on air cooling island FAC,dissolved oxygen takes the second place,and then is the velocity.The utilization of al-kaline agent is associated with the solution's pH value,the interaction between the two can not be neglec-ted.When the dissolved oxygen in water is low,the formation of Fe2 O3 protective film is affected,metals are prone to FAC.By this time,improving dissolved oxygen in water is the effective way to control FAC.%采用正交试验方法研究了空冷岛运行状态下温度、溶解氧含量、pH 值、碱化剂种类和流速对碳钢部件流动加速腐蚀(FAC)的影响.结果表明:温度对空冷岛FAC的影响最大,溶解氧量次之,流速影响较小;碱化剂的使用与 pH 值相关,其联合作用不可忽视;水中溶解氧含量较低时,由于会影响金属表面Fe2 O3保护膜的形成,使得金属易产生 FAC,此时,提高水中溶解氧量可有效抑制FAC.

  19. Factors associated with acute and late dysphagia in the DAHANCA 6 & 7 randomized trial with accelerated radiotherapy for head and neck cancer

    DEFF Research Database (Denmark)

    Mortensen, Hanna Rahbek; Overgaard, Jens; Jensen, Kenneth;

    2013-01-01

    Dysphagia is a common and debilitating side effect in head and neck radiotherapy (RT). Prognostic factors are numerous and their interrelationship not well understood. The aim of this study was to establish a multivariate prognostic model for acute and late dysphagia after RT, based on informatio...

  20. Far field acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

  1. Accelerators and Dinosaurs

    CERN Document Server

    Turner, Michael Stanley

    2003-01-01

    Using naturally occuring particles on which to research might have made accelerators become extinct. But in fact, results from astrophysics have made accelerator physics even more important. Not only are accelerators used in hospitals but they are also being used to understand nature's inner workings by searching for Higgs bosons, CP violation, neutrino mass and dark matter (2 pages)

  2. The CERN Accelerator School

    CERN Multimedia

    2016-01-01

    Introduction to accelerator physics The CERN Accelerator School: Introduction to Accelerator Physics, which should have taken place in Istanbul, Turkey, later this year has now been relocated to Budapest, Hungary.  Further details regarding the new hotel and dates will be made available as soon as possible on a new Indico site at the end of May.

  3. Acceleration: It's Elementary

    Science.gov (United States)

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  4. Association between different risk factors and vascular accelerated ageing (EVA study): study protocol for a cross-sectional, descriptive observational study

    Science.gov (United States)

    Gomez-Marcos, Manuel A; Martinez-Salgado, Carlos; Gonzalez-Sarmiento, Rogelio; Hernandez-Rivas, Jesus Ma; Sanchez-Fernandez, Pedro L; Recio-Rodriguez, Jose I; Rodriguez-Sanchez, Emiliano; García-Ortiz, Luis

    2016-01-01

    Introduction The process of population ageing that is occurring in developed societies represents a major challenge for the health system. The aim of this study is to analyse factors that have an influence on early vascular ageing (EVA), estimated by carotid-femoral pulse wave velocity (cf-PWV) and Cardio Ankle Vascular Index (CAVI), and to determine differences by gender in a Spanish population. Methods and analysis An observational, descriptive, cross-sectional study. Study population From the population assigned to the participating healthcare centres, a cluster random sampling stratified by age and gender will be performed to obtain 500 participants aged between 35 and 75. Those who meet the inclusion criteria and give written informed consent will be included in the study. Measurements Main dependent variables: cf-PWV determined using the SphygmoCor System and CAVI estimated using VASERA. Secondary dependent variables: telomere length, carotid intima-media thickness, central and peripheral augmentation index, ankle-brachial pulse wave velocity, ankle-brachial index, retinal arteriovenous index, and renal and cardiac organ damage. Independent variables: lifestyles (physical activity, adherence to the Mediterranean diet, alcohol and tobacco consumption); psychological factors (depression, anxiety and chronic stress); inflammatory factors and oxidative stress. Ethics and dissemination The study has been approved by the clinical research ethics committee of the healthcare area of Salamanca. All study participants will sign an informed consent form agreeing to participate in the study in compliance with the Declaration of Helsinki and the WHO standards for observational studies. The results of this study will allow the understanding of the relationship of the different influencing factors and their relative weight in the development of EVA. At least 5 publications in first-quartile scientific journals are planned. Trial registration number NCT02623894; Pre

  5. The Accelerator Reliability Forum

    CERN Document Server

    Lüdeke, Andreas; Giachino, R

    2014-01-01

    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  6. Industrial Application of Accelerators

    CERN Document Server

    CERN. Geneva

    2017-01-01

    At CERN, we are very familiar with large, high energy particle accelerators. However, in the world outside CERN, there are more than 35000 accelerators which are used for applications ranging from treating cancer, through making better electronics to removing harmful micro-organisms from food and water. These are responsible for around $0.5T of commerce each year. Almost all are less than 20 MeV and most use accelerator types that are somewhat different from what is at CERN. These lectures will describe some of the most common applications, some of the newer applications in development and the accelerator technology used for them. It will also show examples of where technology developed for particle physics is now being studied for these applications. Rob Edgecock is a Professor of Accelerator Science, with a particular interest in the medical applications of accelerators. He works jointly for the STFC Rutherford Appleton Laboratory and the International Institute for Accelerator Applications at the Univer...

  7. Industrial Application of Accelerators

    CERN Document Server

    CERN. Geneva

    2017-01-01

    At CERN, we are very familiar with large, high energy particle accelerators. However, in the world outside CERN, there are more than 35000 accelerators which are used for applications ranging from treating cancer, through making better electronics to removing harmful micro-organisms from food and water. These are responsible for around $0.5T of commerce each year. Almost all are less than 20 MeV and most use accelerator types that are somewhat different from what is at CERN. These lectures will describe some of the most common applications, some of the newer applications in development and the accelerator technology used for them. It will also show examples of where technology developed for particle physics is now being studied for these applications. Rob Edgecock is a Professor of Accelerator Science, with a particular interest in the medical applications of accelerators. He works jointly for the STFC Rutherford Appleton Laboratory and the International Institute for Accelerator Applications at the Uni...

  8. Harmonic ratcheting for fast acceleration

    Science.gov (United States)

    Cook, N.; Brennan, J. M.; Peggs, S.

    2014-04-01

    A major challenge in the design of rf cavities for the acceleration of medium-energy charged ions is the need to rapidly sweep the radio frequency over a large range. From low-power medical synchrotrons to high-power accelerator driven subcritical reactor systems, and from fixed focus alternating gradient accelerators to rapid cycling synchrotrons, there is a strong need for more efficient, and faster, acceleration of protons and light ions in the semirelativistic range of hundreds of MeV/u. A conventional way to achieve a large, rapid frequency sweep (perhaps over a range of a factor of 6) is to use custom-designed ferrite-loaded cavities. Ferrite rings enable the precise tuning of the resonant frequency of a cavity, through the control of the incremental permeability that is possible by introducing a pseudoconstant azimuthal magnetic field. However, rapid changes over large permeability ranges incur anomalous behavior such as the "Q-loss" and "f-dot" loss phenomena that limit performance while requiring high bias currents. Notwithstanding the incomplete understanding of these phenomena, they can be ameliorated by introducing a "harmonic ratcheting" acceleration scheme in which two or more rf cavities take turns accelerating the beam—one turns on when the other turns off, at different harmonics—so that the radio frequency can be constrained to remain in a smaller range. Harmonic ratcheting also has straightforward performance advantages, depending on the particular parameter set at hand. In some typical cases it is possible to halve the length of the cavities, or to double the effective gap voltage, or to double the repetition rate. This paper discusses and quantifies the advantages of harmonic ratcheting in general. Simulation results for the particular case of a rapid cycling medical synchrotron ratcheting from harmonic number 9 to 2 show that stability and performance criteria are met even when realistic engineering details are taken into consideration.

  9. Using Uncertainty Analysis to Guide the Development of Accelerated Stress Tests (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Kempe, M.

    2014-03-01

    Extrapolation of accelerated testing to the long-term results expected in the field has uncertainty associated with the acceleration factors and the range of possible stresses in the field. When multiple stresses (such as temperature and humidity) can be used to increase the acceleration, the uncertainty may be reduced according to which stress factors are used to accelerate the degradation.

  10. Particle-accelerator decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Opelka, J.H.; Mundis, R.L.; Marmer, G.J.; Peterson, J.M.; Siskind, B.; Kikta, M.J.

    1979-12-01

    Generic considerations involved in decommissioning particle accelerators are examined. There are presently several hundred accelerators operating in the United States that can produce material containing nonnegligible residual radioactivity. Residual radioactivity after final shutdown is generally short-lived induced activity and is localized in hot spots around the beam line. The decommissioning options addressed are mothballing, entombment, dismantlement with interim storage, and dismantlement with disposal. The recycle of components or entire accelerators following dismantlement is a definite possibility and has occurred in the past. Accelerator components can be recycled either immediately at accelerator shutdown or following a period of storage, depending on the nature of induced activation. Considerations of cost, radioactive waste, and radiological health are presented for four prototypic accelerators. Prototypes considered range from small accelerators having minimal amounts of radioactive mmaterial to a very large accelerator having massive components containing nonnegligible amounts of induced activation. Archival information on past decommissionings is presented, and recommendations concerning regulations and accelerator design that will aid in the decommissioning of an accelerator are given.

  11. Accelerator and radiation physics

    CERN Document Server

    Basu, Samita; Nandy, Maitreyee

    2013-01-01

    "Accelerator and radiation physics" encompasses radiation shielding design and strategies for hadron therapy accelerators, neutron facilities and laser based accelerators. A fascinating article describes detailed transport theory and its application to radiation transport. Detailed information on planning and design of a very high energy proton accelerator can be obtained from the article on radiological safety of J-PARC. Besides safety for proton accelerators, the book provides information on radiological safety issues for electron synchrotron and prevention and preparedness for radiological emergencies. Different methods for neutron dosimetry including LET based monitoring, time of flight spectrometry, track detectors are documented alongwith newly measured experimental data on radiation interaction with dyes, polymers, bones and other materials. Design of deuteron accelerator, shielding in beam line hutches in synchrotron and 14 MeV neutron generator, various radiation detection methods, their characteriza...

  12. Leaky Fermi accelerators

    CERN Document Server

    Shah, Kushal; Rom-Kedar, Vered; Turaev, Dmitry

    2015-01-01

    A Fermi accelerator is a billiard with oscillating walls. A leaky accelerator interacts with an environment of an ideal gas at equilibrium by exchange of particles through a small hole on its boundary. Such interaction may heat the gas: we estimate the net energy flow through the hole under the assumption that the particles inside the billiard do not collide with each other and remain in the accelerator for sufficiently long time. The heat production is found to depend strongly on the type of the Fermi accelerator. An ergodic accelerator, i.e. one which has a single ergodic component, produces a weaker energy flow than a multi-component accelerator. Specifically, in the ergodic case the energy gain is independent of the hole size, whereas in the multi-component case the energy flow may be significantly increased by shrinking the hole size.

  13. Accelerator reliability workshop

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, L.; Duru, Ph.; Koch, J.M.; Revol, J.L.; Van Vaerenbergh, P.; Volpe, A.M.; Clugnet, K.; Dely, A.; Goodhew, D

    2002-07-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop.

  14. Ponderomotive Acceleration in Coronal Loops

    Science.gov (United States)

    Dahlburg, R. B.; Laming, J. M.; Taylor, B. D.; Obenschain, K.

    2016-11-01

    Ponderomotive acceleration has been asserted to be a cause of the first ionization potential (FIP) effect, the well-known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a “by-product” of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of coronal loops with an axial magnetic field from 0.005 to 0.02 T and lengths from 25,000 to 75,000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets, which act to heat the loop. As a consequence of coronal magnetic reconnection, small-scale, high-speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.

  15. Accelerating proliferation of neural stem/progenitor cells in collagen sponges immobilized with engineered basic fibroblast growth factor for nervous system tissue engineering.

    Science.gov (United States)

    Ma, Fukai; Xiao, Zhifeng; Chen, Bing; Hou, Xianglin; Han, Jin; Zhao, Yannan; Dai, Jianwu; Xu, Ruxiang

    2014-03-10

    Neural stem/progenitor cells (NS/PCs) play a therapeutic role in nervous system diseases and contribute to functional recovery. However, their efficacy is limited as the majority of cells die post-transplantation. In this study, collagen sponges were utilized as carriers for NS/PCs. Basic fibroblast growth factor (bFGF), a mitogen for NS/PCs, was incorporated into the collagen sponges to stimulate NS/PC proliferation. However, the effect of native bFGF is limited because it diffuses into the culture medium and is lost following medium exchange. To overcome this problem, a collagen-binding polypeptide domain, which has high affinity to collagen, was fused with bFGF to sustain the exposure of NS/PCs within the collagen sponges to bFGF. The results indicated that the number of NS/PCs was significantly higher in collagen sponges incorporating engineered bFGF than in those with native bFGF or the PBS control after 7 days in culture. Here, we designed a natural biological neural scaffold consisting of collagen sponges, engineered bFGF, and NS/PCs. In addition to the effect of proliferated NS/PCs, the engineered bFGF retained in the natural biological neural scaffolds could have a direct effect on nervous system reconstruction. The two aspects of the natural biological neural scaffolds may produce synergistic effects, and so they represent a promising candidate for nervous system repair.

  16. Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte Carlo-GEANT4 simulations for IORT mobile dedicate accelerator

    Science.gov (United States)

    Marrale, Maurizio; Longo, Anna; Russo, Giorgio; Casarino, Carlo; Candiano, Giuliana; Gallo, Salvatore; Carlino, Antonio; Brai, Maria

    2015-09-01

    In this work a comparison between the response of alanine and Markus ionization chamber was carried out for measurements of the output factors (OF) of electron beams produced by a linear accelerator used for Intra-Operative Radiation Therapy (IORT). Output factors (OF) for conventional high-energy electron beams are normally measured using ionization chamber according to international dosimetry protocols. However, the electron beams used in IORT have characteristics of dose per pulse, energy spectrum and angular distribution quite different from beams usually used in external radiotherapy, so the direct application of international dosimetry protocols may introduce additional uncertainties in dosimetric determinations. The high dose per pulse could lead to an inaccuracy in dose measurements with ionization chamber, due to overestimation of ks recombination factor. Furthermore, the electron fields obtained with IORT-dedicated applicators have a wider energy spectrum and a wider angular distribution than the conventional fields, due to the presence of electrons scattered by the applicator's wall. For this reason, a dosimetry system should be characterized by a minimum dependence from the beam energy and from angle of incidence of electrons. This become particularly critical for small and bevelled applicators. All of these reasons lead to investigate the use of detectors different from the ionization chamber for measuring the OFs. Furthermore, the complete characterization of the radiation field could be accomplished also by the use of Monte Carlo simulations which allows to obtain detailed information on dose distributions. In this work we compare the output factors obtained by means of alanine dosimeters and Markus ionization chamber. The comparison is completed by the Monte Carlo calculations of OFs determined through the use of the Geant4 application "iort _ therapy" . The results are characterized by a good agreement of response of alanine pellets and Markus

  17. Power Converters for Accelerators

    CERN Document Server

    Visintini, R

    2015-01-01

    Particle accelerators use a great variety of power converters for energizing their sub-systems; while the total number of power converters usually depends on the size of the accelerator or combination of accelerators (including the experimental setup), the characteristics of power converters depend on their loads and on the particle physics requirements: this paper aims to provide an overview of the magnet power converters in use in several facilities worldwide.

  18. High Gradient Accelerator Research

    Energy Technology Data Exchange (ETDEWEB)

    Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Physics. Plasma Science and Fusion Center

    2016-07-12

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  19. The accelerating structure of the IFUSP microtron

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, J.; Martins, M.N.; Lima, J.A. de; Malafronte, A.A.; Portante, L.; Cruz, M.T.F. da; Pascholati, P.R. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1997-10-01

    The accelerating structure for ultra-relativistic electrons ({beta}=1) of the IFUSP microtron accelerator is described. We present the main characteristics of the structure and discuss some of the expected properties of the project, such as effective shunt impedance, coupling factor and accelerating field distribution, based on calculations. We describe the construction procedures, from the machining and pre-tuning of the cavities, to the brazing process and the final tuning of the whole structure. The final results obtained for the structure are presented and the dynamic tuning system based on moving plungers described. (author). 1 ref., 3 figs., 2 tabs.

  20. KEK digital accelerator

    Science.gov (United States)

    Iwashita, T.; Adachi, T.; Takayama, K.; Leo, K. W.; Arai, T.; Arakida, Y.; Hashimoto, M.; Kadokura, E.; Kawai, M.; Kawakubo, T.; Kubo, Tomio; Koyama, K.; Nakanishi, H.; Okazaki, K.; Okamura, K.; Someya, H.; Takagi, A.; Tokuchi, A.; Wake, M.

    2011-07-01

    The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA) is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR) ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

  1. Accelerators Beyond The Tevatron?

    Energy Technology Data Exchange (ETDEWEB)

    Lach, Joseph; /Fermilab

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  2. COLLECTIVE-FIELD ACCELERATION

    Energy Technology Data Exchange (ETDEWEB)

    Sessler, Andrew M.

    1969-07-04

    Diverse methods proposed for the acceleration of particles by means of collective fields are reviewed. A survey is made of the various currently active experimental programs devoted to investigating collective acceleration, and the present status of the research is briefly noted.

  3. Asia honours accelerator physicists

    CERN Multimedia

    2010-01-01

    "Steve Meyers of Cern and Jie Wei of Beijing's Tsinghua University are the first recipients of a new prize for particle physics. The pair were honoured for their contributions to numerous particle-accelerator projects - including Cern's Large Hadron Collider - by the Asian Committee for Future Accelerators (ACFA)..." (1 paragraph)

  4. Accelerating DSMC data extraction.

    Energy Technology Data Exchange (ETDEWEB)

    Gallis, Michail A.; Piekos, Edward Stanley

    2006-10-01

    In many direct simulation Monte Carlo (DSMC) simulations, the majority of computation time is consumed after the flowfield reaches a steady state. This situation occurs when the desired output quantities are small compared to the background fluctuations. For example, gas flows in many microelectromechanical systems (MEMS) have mean speeds more than two orders of magnitude smaller than the thermal speeds of the molecules themselves. The current solution to this problem is to collect sufficient samples to achieve the desired resolution. This can be an arduous process because the error is inversely proportional to the square root of the number of samples so we must, for example, quadruple the samples to cut the error in half. This work is intended to improve this situation by employing more advanced techniques, from fields other than solely statistics, for determining the output quantities. Our strategy centers on exploiting information neglected by current techniques, which collect moments in each cell without regard to one another, values in neighboring cells, nor their evolution in time. Unlike many previous acceleration techniques that modify the method itself, the techniques examined in this work strictly post-process so they may be applied to any DSMC code without affecting its fidelity or generality. Many potential methods are drawn from successful applications in a diverse range of areas, from ultrasound imaging to financial market analysis. The most promising methods exploit relationships between variables in space, which always exist in DSMC due to the absence of shocks. Disparate techniques were shown to produce similar error reductions, suggesting that the results shown in this report may be typical of what is possible using these methods. Sample count reduction factors of approximately three to five were found to be typical, although factors exceeding ten were shown on some variables under some techniques.

  5. Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams

    Energy Technology Data Exchange (ETDEWEB)

    Siemann, R.H.; /SLAC

    2011-10-24

    Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

  6. The Accelerated Kepler Problem

    CERN Document Server

    Namouni, Fathi

    2007-01-01

    The accelerated Kepler problem is obtained by adding a constant acceleration to the classical two-body Kepler problem. This setting models the dynamics of a jet-sustaining accretion disk and its content of forming planets as the disk loses linear momentum through the asymmetric jet-counterjet system it powers. The dynamics of the accelerated Kepler problem is analyzed using physical as well as parabolic coordinates. The latter naturally separate the problem's Hamiltonian into two unidimensional Hamiltonians. In particular, we identify the origin of the secular resonance in the accelerated Kepler problem and determine analytically the radius of stability boundary of initially circular orbits that are of particular interest to the problem of radial migration in binary systems as well as to the truncation of accretion disks through stellar jet acceleration.

  7. On Accelerated Black Holes

    CERN Document Server

    Letelier, P S; Letelier, Patricio S.; Oliveira, Samuel R.

    1998-01-01

    The C-metric is revisited and global interpretation of some associated spacetimes are studied in some detail. Specially those with two event horizons, one for the black hole and another for the acceleration. We found that the spacetime fo an accelerated Schwarzschild black hole is plagued by either conical singularities or lack of smoothness and compactness of the black hole horizon. By using standard black hole thermodynamics we show that accelerated black holes have higher Hawking temperature than Unruh temperature. We also show that the usual upper bound on the product of the mass and acceleration parameters (<1/sqrt(27)) is just a coordinate artifact. The main results are extended to accelerated Kerr black holes. We found that they are not changed by the black hole rotation.

  8. Chotosan (Diaoteng San-induced improvement of cognitive deficits in senescence-accelerated mouse (SAMP8 involves the amelioration of angiogenic/neurotrophic factors and neuroplasticity systems in the brain

    Directory of Open Access Journals (Sweden)

    Tanaka Ken

    2011-09-01

    Full Text Available Abstract Background Chotosan (CTS, Diaoteng San, a Kampo medicine (ie Chinese medicine formula, is reportedly effective in the treatment of patients with cerebral ischemic insults. This study aims to evaluate the therapeutic potential of CTS in cognitive deficits and investigates the effects and molecular mechanism(s of CTS on learning and memory deficits and emotional abnormality in an animal aging model, namely 20-week-old senescence-accelerated prone mice (SAMP8, with and without a transient ischemic insult (T2VO. Methods Age-matched senescence-resistant inbred strain mice (SAMR1 were used as control. SAMP8 received T2VO (T2VO-SAMP8 or sham operation (sham-SAMP8 at day 0. These SAMP8 groups were administered CTS (750 mg/kg, p.o. or water daily for three weeks from day 3. Results Compared with the control group, both sham-SAMP8 and T2VO-SAMP8 groups exhibited cognitive deficits in the object discrimination and water maze tests and emotional abnormality in the elevated plus maze test. T2VO significantly exacerbated spatial cognitive deficits of SAMP8 elucidated by the water maze test. CTS administration ameliorated the cognitive deficits and emotional abnormality of sham- and T2VO-SAMP8 groups. Western blotting and immunohistochemical studies revealed a marked decrease in the levels of phosphorylated forms of neuroplasticity-related proteins, N-methyl-D-aspartate receptor 1 (NMDAR1, Ca2+/calmodulin-dependent protein kinase II (CaMKII, cyclic AMP responsive element binding protein (CREB and brain-derived neurotrophic factor (BDNF in the frontal cortices of sham-SAMP8 and T2VO-SAMP8. Moreover, these animal groups showed significantly reduced levels of vasculogenesis/angiogenesis factors, vascular endothelial growth factor (VEGF, VEGF receptor type 2 (VEGFR2, platelet-derived growth factor-A (PDGF-A and PDGF receptor α (PDGFRα. CTS treatment reversed the expression levels of these factors down-regulated in the brains of sham- and T2VO-SAMP8

  9. Recombinant human thrombopoietin in combination with granulocyte colony-stimulating factor enhances mobilization of peripheral blood progenitor cells, increases peripheral blood platelet concentration, and accelerates hematopoietic recovery following high-dose chemotherapy.

    Science.gov (United States)

    Somlo, G; Sniecinski, I; ter Veer, A; Longmate, J; Knutson, G; Vuk-Pavlovic, S; Bhatia, R; Chow, W; Leong, L; Morgan, R; Margolin, K; Raschko, J; Shibata, S; Tetef, M; Yen, Y; Forman, S; Jones, D; Ashby, M; Fyfe, G; Hellmann, S; Doroshow, J H

    1999-05-01

    Lineage-specific growth factors mobilize peripheral blood progenitor cells (PBPC) and accelerate hematopoietic recovery after high-dose chemotherapy. Recombinant human thrombopoietin (rhTPO) may further increase the progenitor-cell content and regenerating potential of PBPC products. We evaluated the safety and activity of rhTPO as a PBPC mobilizer in combination with granulocyte colony-stimulating factor (G-CSF) in 29 breast cancer patients treated with high-dose chemotherapy followed by PBPC reinfusion. Initially, patients received escalating single doses of rhTPO intravenously (IV) at 0.6, 1.2, or 2.4 micrograms/kg, on day 1. Subsequent patients received rhTPO 0.6 or 0.3 micrograms/kg on days -3, -1, and 1, or 0.6 micrograms/kg on days -1 and 1. G-CSF, 5 micrograms/kg IV or subcutaneously (SC) twice daily, was started on day 3 and continued through aphereses. Twenty comparable, concurrently and identically treated patients (who were eligible and would have been treated on protocol but for the lack of study opening) mobilized with G-CSF alone served as comparisons. CD34(+) cell yields were substantially higher with the first apheresis following rhTPO and G-CSF versus G-CSF alone: 4.1 x 10(6)/kg (range, 1.3 to 17.6) versus 0.8 x 10(6)/ kg (range, 0.3 to 4.2), P =.0003. The targeted minimum yield of 3 x 10(6) CD34(+) cells/kg was procured following a single apheresis procedure in 61% of the rhTPO and G-CSF-mobilized group versus 10% of G-CSF-mobilized patients (P =.001). In rhTPO and G-CSF mobilized patients, granulocyte (day 8 v 9, P =.0001) and platelet recovery (day 9 v 10, P =.07) were accelerated, and fewer erythrocyte (3 v 4, P =.02) and platelet (4 v 5, P =.02) transfusions were needed compared with G-CSF-mobilized patients. Peripheral blood platelet counts, following rhTPO and G-CSF, were increased by greater than 100% and the platelet content of PBPC products by 60% to 110% on the first and second days of aphereses (P rhTPO at 0.6 microgram/kg. rhTPO is

  10. Cosmic particle acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Zimbardo, Gaetano; Perri, Silvia [Universita della Calabria, Dipartimento di Fisica, 87036 Rende (Italy)

    2014-07-01

    The most popular mechanism for the acceleration of cosmic rays, which is thought to operate in supernova remnant shocks as well as at heliospheric shocks, is the diffusive shock acceleration, which is a Fermi mechanism based on normal diffusion. On the other hand, in the last few years it has been shown that the transport of plasma particles in the presence of electric and magnetic turbulence can be superdiffusive rather than normal diffusive. The term 'superdiffusive' refers to the mean square displacement of particle positions growing superlinearly with time, as compared to the normal linear growth. In particular, superdiffusion is characterized by a non Gaussian statistical process called Levy random walk. We show how diffusive shock acceleration is modified by superdiffusion, and how this yields new predictions for the cosmic ray spectral index, for the acceleration time, and for the spatial profile of energetic particles. A comparison with observations of particle acceleration at heliospheric shocks and at supernova remnant shocks is done. We discuss how superdiffusive shock acceleration allows to explain the observations of hard ion spectra at the solar wind termination shock detected by Voyager 2, of hard radio spectra due to synchrotron emission of electrons accelerated at supernova remnant shocks, and how it can help to explain the observations of 'thin rims' in the X-ray synchrotron emission.

  11. The miniature accelerator

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    The image that most people have of CERN is of its enormous accelerators and their capacity to accelerate particles to extremely high energies. But thanks to some cutting-edge studies on beam dynamics and radiofrequency technology, along with innovative construction techniques, teams at CERN have now created the first module of a brand-new accelerator, which will be just 2 metres long. The potential uses of this miniature accelerator will include deployment in hospitals for the production of medical isotopes and the treatment of cancer. It’s a real David-and-Goliath story.   Serge Mathot, in charge of the construction of the "mini-RFQ", pictured with the first of the four modules that will make up the miniature accelerator. The miniature accelerator consists of a radiofrequency quadrupole (RFQ), a component found at the start of all proton accelerator chains around the world, from the smallest to the largest. The LHC is designed to produce very high-intensity beams ...

  12. 基于CFD前处理软件的潜艇加速度系数势流计算方法%A potential flow method for evaluation acceleration factor of submarine based on CFD pre-processor

    Institute of Scientific and Technical Information of China (English)

    林兆伟; 涂卫民; 郭传海; 李新汶

    2013-01-01

      A method of 3 D panel method combined CFD pre-processor was used to calculate the acceleration factor for submarine design in this paper, the improved method was presented instead of traditional panel method for enhancing work efficiency. To inspect calculation precision, a comparison between model test and calculations was investigated for three submarine models, the results show this method can effectively overcome the shortcomings of traditional method in the geometric description and helps enhance calculation precision obviously.%  采用CFD前处理软件和势流计算相结合的方法,解决潜艇设计中的加速度系数计算问题,对传统方法进行合理改进和优化,提高了工作效率。为检验该方法计算精度,文中计算了3种艇型模型,计算结果用模型试验验证。结果表明,此方法可以有效克服传统面元处理方法对潜艇复杂局部结构几何描述能力不足的缺陷,提高了计算精度。

  13. Application of Accelerators and Storage Rings: Accelerators in Medicine

    CERN Document Server

    Amaldi, U

    2013-01-01

    This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the the Section '11.3 Accelerators in Medicine' of the Chapter '11 Application of Accelerators and Storage Rings' with the content: 11.3 Accelerators in Medicine 11.3.1 Accelerators and Radiopharmaceuticals 11.3.2 Accelerators and Cancer Therapy

  14. Confronting Twin Paradox Acceleration

    Science.gov (United States)

    Murphy, Thomas W.

    2016-05-01

    The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity β ≡v/c .

  15. Up-regulation of intestinal vascular endothelial growth factor by Afa/Dr diffusely adhering Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Gaëlle Cane

    Full Text Available BACKGROUND: Angiogenesis has been recently described as a novel component of inflammatory bowel disease pathogenesis. The level of vascular endothelial growth factor (VEGF has been found increased in Crohn's disease and ulcerative colitis mucosa. To question whether a pro-inflammatory Escherichia coli could regulate the expression of VEGF in human intestinal epithelial cells, we examine the response of cultured human colonic T84 cells to infection by E. coli strain C1845 that belongs to the typical Afa/Dr diffusely adhering E. coli family (Afa/Dr DAEC. METHODOLOGY: VEGF mRNA expression was examined by Northern blotting and q-PCR. VEGF protein levels were assayed by ELISA and its bioactivity was analysed in endothelial cells. The bacterial factor involved in VEGF induction was identified using recombinant E. coli expressing Dr adhesin, purified Dr adhesin and lipopolysaccharide. The signaling pathway activated for the up-regulation of VEGF was identified using a blocking monoclonal anti-DAF antibody, Western blot analysis and specific pharmacological inhibitors. PRINCIPAL FINDINGS: C1845 bacteria induce the production of VEGF protein which is bioactive. VEGF is induced by adhering C1845 in both a time- and bacteria concentration-dependent manner. This phenomenon is not cell line dependent since we reproduced this observation in intestinal LS174, Caco2/TC7 and INT407 cells. Up-regulation of VEGF production requires: (1 the interaction of the bacterial F1845 adhesin with the brush border-associated decay accelerating factor (DAF, CD55 acting as a bacterial receptor, and (2 the activation of a Src protein kinase upstream of the activation of the Erk and Akt signaling pathways. CONCLUSIONS: Results demonstrate that a Afa/Dr DAEC strain induces an adhesin-dependent activation of DAF signaling that leads to the up-regulation of bioactive VEGF in cultured human intestinal cells. Thus, these results suggest a link between an entero-adherent, pro

  16. Accelerated Hypertension after Venlafaxine Usage

    Directory of Open Access Journals (Sweden)

    Yüksel Kıvrak

    2014-01-01

    Full Text Available Venlafaxine is the first antidepressant that acts via inhibiting serotonin and noradrenaline reuptake. Hypertension is observed in doses exceeding 300 mg/day and is the most feared complication. We report a patient with accelerated hypertension after venlafaxine use observed at a dose of 150 mg/day. A 23-year-old patient with symptoms of insomnia, depression, anhedonia, fatigue admitted our clinic. Venlafaxine at a dose of 75 mg/day was initiated after he was diagnosed with major depressive disorder. After 5 months, venlafaxine dose was uptitrated to 150 mg/day due to inadequate response to drug. After using venlafaxine for ten months at the dose of 150 mg/day, he admitted our clinic with headache and epistaxis. He was hospitalized after his blood pressure was measured as 210/170 mmHg. No secondary causes for hypertension were found, and venlafaxine treatment was considered possible etiologic factor. After stopping venlafaxine treatment, his blood pressure was reverted back to normal limits. While mild elevation of blood pressure could be observed after venlafaxine treatment, this case shows that accelerated hypertension with a diastolic blood pressure rise above 120 mmHg could be observed at relatively low doses of venlafaxine. Close monitoring of blood pressure is necessary after initiation of treatment, as accelerated hypertension could cause endorgan damage with potentially catastrophic results.

  17. Vibration control in accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Montag, C.

    2011-01-01

    In the vast majority of accelerator applications, ground vibration amplitudes are well below tolerable magnet jitter amplitudes. In these cases, it is necessary and sufficient to design a rigid magnet support structure that does not amplify ground vibration. Since accelerator beam lines are typically installed at an elevation of 1-2m above ground level, special care has to be taken in order to avoid designing a support structure that acts like an inverted pendulum with a low resonance frequency, resulting in untolerable lateral vibration amplitudes of the accelerator components when excited by either ambient ground motion or vibration sources within the accelerator itself, such as cooling water pumps or helium flow in superconducting magnets. In cases where ground motion amplitudes already exceed the required jiter tolerances, for instance in future linear colliders, passive vibration damping or active stabilization may be considered.

  18. Joint International Accelerator School

    CERN Multimedia

    CERN Accelerator School

    2014-01-01

    The CERN and US Particle Accelerator Schools recently organised a Joint International Accelerator School on Beam Loss and Accelerator Protection, held at the Hyatt Regency Hotel, Newport Beach, California, USA from 5-14 November 2014. This Joint School was the 13th in a series of such schools, which started in 1985 and also involves the accelerator communities in Japan and Russia.   Photo courtesy of Alfonse Pham, Michigan State University.   The school attracted 58 participants representing 22 different nationalities, with around half from Europe and the other half from Asia and the Americas. The programme comprised 26 lectures, each of 90 minutes, and 13 hours of case study. The students were given homework each day and had an opportunity to sit a final exam, which counted towards university credit. Feedback from the participants was extremely positive, praising the expertise and enthusiasm of the lecturers, as well as the high standard and quality of their lectures. Initial dis...

  19. Rejuvenating CERN's Accelerators

    CERN Multimedia

    2004-01-01

    In the coming years and especially in 2005, CERN's accelerators are going to receive an extensive renovation programme to ensure they will perform reliably and effectively when the LHC comes into service.

  20. Accelerating Cosmologies from Compactification

    CERN Document Server

    Townsend, P K; Townsend, Paul K.; Wohlfarth, Mattias N.R.

    2003-01-01

    A solution of the (4+n)-dimensional vacuum Einstein equations is found for which spacetime is compactified on a compact hyperbolic manifold of time-varying volume to a flat four-dimensional FLRW cosmology undergoing accelerated expansion in Einstein conformal frame. This shows that the `no-go' theorem forbidding acceleration in `standard' (time-independent) compactifications of string/M-theory does not apply to `cosmological' (time-dependent) hyperbolic compactifications.

  1. Accelerating News Issue 2

    CERN Document Server

    Kahle, K; Wildner, E

    2012-01-01

    In this summer issue we look at how developments in collimator materials could have applications in aerospace and beyond, and how Polish researchers are harnessing accelerators for medical and industrial uses. We see how the LHC luminosity upgrade is linking with European industry and US researchers, and how the neutrino oscillation community is progressing. We find out the mid-term status of TIARA-PP and how it is mapping European accelerator education resources.

  2. Biomedical accelerator mass spectrometry

    Science.gov (United States)

    Freeman, Stewart P. H. T.; Vogel, John S.

    1995-05-01

    Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

  3. Accelerators for America's Future

    Science.gov (United States)

    Bai, Mei

    2016-03-01

    Particle accelerator, a powerful tool to energize beams of charged particles to a desired speed and energy, has been the working horse for investigating the fundamental structure of matter and fundermental laws of nature. Most known examples are the 2-mile long Stanford Linear Accelerator at SLAC, the high energy proton and anti-proton collider Tevatron at FermiLab, and Large Hadron Collider that is currently under operation at CERN. During the less than a century development of accelerator science and technology that led to a dazzling list of discoveries, particle accelerators have also found various applications beyond particle and nuclear physics research, and become an indispensible part of the economy. Today, one can find a particle accelerator at almost every corner of our lives, ranging from the x-ray machine at the airport security to radiation diagnostic and therapy in hospitals. This presentation will give a brief introduction of the applications of this powerful tool in fundermental research as well as in industry. Challenges in accelerator science and technology will also be briefly presented

  4. Diffusive Shock Acceleration and Reconnection Acceleration Processes

    Science.gov (United States)

    Zank, G. P.; Hunana, P.; Mostafavi, P.; Le Roux, J. A.; Li, Gang; Webb, G. M.; Khabarova, O.; Cummings, A.; Stone, E.; Decker, R.

    2015-12-01

    Shock waves, as shown by simulations and observations, can generate high levels of downstream vortical turbulence, including magnetic islands. We consider a combination of diffusive shock acceleration (DSA) and downstream magnetic-island-reconnection-related processes as an energization mechanism for charged particles. Observations of electron and ion distributions downstream of interplanetary shocks and the heliospheric termination shock (HTS) are frequently inconsistent with the predictions of classical DSA. We utilize a recently developed transport theory for charged particles propagating diffusively in a turbulent region filled with contracting and reconnecting plasmoids and small-scale current sheets. Particle energization associated with the anti-reconnection electric field, a consequence of magnetic island merging, and magnetic island contraction, are considered. For the former only, we find that (i) the spectrum is a hard power law in particle speed, and (ii) the downstream solution is constant. For downstream plasmoid contraction only, (i) the accelerated spectrum is a hard power law in particle speed; (ii) the particle intensity for a given energy peaks downstream of the shock, and the distance to the peak location increases with increasing particle energy, and (iii) the particle intensity amplification for a particular particle energy, f(x,c/{c}0)/f(0,c/{c}0), is not 1, as predicted by DSA, but increases with increasing particle energy. The general solution combines both the reconnection-induced electric field and plasmoid contraction. The observed energetic particle intensity profile observed by Voyager 2 downstream of the HTS appears to support a particle acceleration mechanism that combines both DSA and magnetic-island-reconnection-related processes.

  5. Small type accelerator. Try for accelerator driven system

    CERN Document Server

    Mori, Y

    2003-01-01

    FFAG (Fixed-field alternating gradient) accelerator for accelerator driven subcritical reactor, which aims to change from long-lived radioactive waste to short-lived radioactivity, is introduced. It is ring accelerator. The performance needed is proton as accelerator particle, 10MW (total) beam power, about 1GeV beam energy, >30% power efficiency and continuous beam. The feature of FFAG accelerator is constant magnetic field. PoP (Proof-of-principle)-FFAG accelerator, radial type, was run at first in Japan in 2000. The excursion is about some ten cm. In principle, beam can be injected and extracted at any place of ring. The 'multi-fish' acceleration can accelerate beams to 100% duty by repeating acceleration. 150MeV-FFAG accelerator has been started since 2001. It tried to practical use, for example, treatment of cancer. (S.Y.)

  6. Dielectric laser accelerators

    Science.gov (United States)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

    2014-10-01

    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  7. Plasma-based accelerator structures

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Carl B. [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  8. Superconducting Accelerator Magnets

    CERN Document Server

    Mess, K H; Wolff, S

    1996-01-01

    The main topic of the book are the superconducting dipole and quadrupole magnets needed in high-energy accelerators and storage rings for protons, antiprotons or heavy ions. The basic principles of low-temperature superconductivity are outlined with special emphasis on the effects which are relevant for accelerator magnets. Properties and fabrication methods of practical superconductors are described. Analytical methods for field calculation and multipole expansion are presented for coils without and with iron yoke. The effect of yoke saturation and geometric distortions on field quality is studied. Persistent magnetization currents in the superconductor and eddy currents the copper part of the cable are analyzed in detail and their influence on field quality and magnet performance is investigated. Superconductor stability, quench origins and propagation and magnet protection are addressed. Some important concepts of accelerator physics are introduced which are needed to appreciate the demanding requirements ...

  9. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2007-01-01

    Particle Accelerator Physics is an in-depth and comprehensive introduction to the field of high-energy particle acceleration and beam dynamics. Part I gathers the basic tools, recalling the essentials of electrostatics and electrodynamics as well as of particle dynamics in electromagnetic fields. Part II is an extensive primer in beam dynamics, followed in Part III by the introduction and description of the main beam parameters. Part IV is devoted to the treatment of perturbations in beam dynamics. Part V discusses the details of charged particle accleration. Part VI and Part VII introduce the more advanced topics of coupled beam dynamics and the description of very intense beams. Part VIII is an exhaustive treatment of radiation from accelerated charges and introduces important sources of coherent radiation such as synchrotrons and free-electron lasers. Part IX collects the appendices gathering useful mathematical and physical formulae, parameters and units. Solutions to many end-of-chapter problems are give...

  10. Uniform Acceleration in General Relativity

    CERN Document Server

    Friedman, Yaakov

    2016-01-01

    We extend de la Fuente and Romero's defining equation for uniform acceleration in a general curved spacetime from linear acceleration to the full Lorentz covariant uniform acceleration. In a flat spacetime background, we have explicit solutions. We use generalized Fermi-Walker transport to parallel transport the Frenet basis along the trajectory. In flat spacetime, we obtain velocity and acceleration transformations from a uniformly accelerated system to an inertial system. We obtain the time dilation between accelerated clocks. We apply our acceleration transformations to the motion of a charged particle in a constant electromagnetic field and recover the Lorentz-Abraham-Dirac equation.

  11. Microelectromechanical acceleration-sensing apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Robb M. (Albuquerque, NM); Shul, Randy J. (Albuquerque, NM); Polosky, Marc A. (Albuquerque, NM); Hoke, Darren A. (Albuquerque, NM); Vernon, George E. (Rio Rancho, NM)

    2006-12-12

    An acceleration-sensing apparatus is disclosed which includes a moveable shuttle (i.e. a suspended mass) and a latch for capturing and holding the shuttle when an acceleration event is sensed above a predetermined threshold level. The acceleration-sensing apparatus provides a switch closure upon sensing the acceleration event and remains latched in place thereafter. Examples of the acceleration-sensing apparatus are provided which are responsive to an acceleration component in a single direction (i.e. a single-sided device) or to two oppositely-directed acceleration components (i.e. a dual-sided device). A two-stage acceleration-sensing apparatus is also disclosed which can sense two acceleration events separated in time. The acceleration-sensing apparatus of the present invention has applications, for example, in an automotive airbag deployment system.

  12. Studies of accelerated compact toruses

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, C.W.; Eddleman, J.; Hammer, J.H.

    1983-01-04

    In an earlier publication we considered acceleration of plasma rings (Compact Torus). Several possible accelerator configurations were suggested and the possibility of focusing the accelerated rings was discussed. In this paper we consider one scheme, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focusing) during acceleration. Because the allowable acceleration force, F/sub a/ = kappaU/sub m//R where (kappa < 1), increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case, however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency.

  13. GPU Accelerated Surgical Simulators for Complex Morhpology

    DEFF Research Database (Denmark)

    Mosegaard, Jesper; Sørensen, Thomas Sangild

    2005-01-01

    a springmass system in order to simulate a complex organ such as the heart. Computations are accelerated by taking advantage of modern graphics processing units (GPUs). Two GPU implementations are presented. They vary in their generality of spring connections and in the speedup factor they achieve...

  14. Social emotional consequences of accelerating gifted students

    NARCIS (Netherlands)

    Hoogeveen, A.J.M.

    2008-01-01

    This dissertations reports four studies on the social-emotional effects of accelerating gifted students. The research concentrated on how and to what extent educational programs, in interaction with environmental and personal factors, influence the functioning of gifted students, in the short and th

  15. Accelerating News Issue 4

    CERN Document Server

    Szeberenyi, A; Wildner, E

    2012-01-01

    In this winter issue, we are very pleased to announce the approval of EuCARD-2 by the European Commission. We look at the conclusions of EUROnu in proposing future neutrino facilities at CERN, a new milestone reached by CLIC and progress on the SPARC upgrade using C-band technology. We also report on recent events: second Joint HiLumi LHC-LARP Annual Meeting and workshop on Superconducting technologies for the Next Generation of Accelerators aiming at closer collaboration with industry. The launch of the Accelerators for Society brochure is also highlighted.

  16. Shielding high energy accelerators

    CERN Document Server

    Stevenson, Graham Roger

    2001-01-01

    After introducing the subject of shielding high energy accelerators, point source, line-of-sight models, and in particular the Moyer model. are discussed. Their use in the shielding of proton and electron accelerators is demonstrated and their limitations noted. especially in relation to shielding in the forward direction provided by large, flat walls. The limitations of reducing problems to those using it cylindrical geometry description are stressed. Finally the use of different estimators for predicting dose is discussed. It is suggested that dose calculated from track-length estimators will generally give the most satisfactory estimate. (9 refs).

  17. Backward Raman Amplifier for Laser Wakefield Accelerator

    Science.gov (United States)

    Ludwig, Joshua; Masson-Laborde, Paul-Edouard; Huller, Stefan; Rozmus, Wojciech; Wilks, Scott C.

    2016-10-01

    Particle in cell simulations via SCPIC and theoretical work on Raman amplification and laser wake field acceleration will be presented. Laser energy depletion has been shown to be a limiting factor during wake field acceleration. This work focuses on optimizing parameters for Raman amplification to work in conjunction with wake field acceleration in order in order to sustain an accelerating laser pulse as it generates plasma waves. It has been shown that laser pulses undergo red shifting during wake generation. Our work demonstrates that this red shifting results in a detuning between pump and seed in the backward Raman Amplifier. This detuning limits the amount of energy that can be transferred from the pump to the seed, and places new limits on backward Raman amplification. To overcome this limiting factor, this study makes use of a chirped pump allowing for extended coupling to the accelerating pulse. Three wave coupling model of Raman amplifier with a frequency shift term due to wake field will also be discussed and compared with PIC simulations.

  18. Effect of basic fibroblast growth factor and danshen on bcl-2 and p53 mRNA expression in the brain of rats exposed to repeated,high,positive acceleration(+Gz)

    Institute of Scientific and Technical Information of China (English)

    Hongjin Liu; Qing Cai

    2008-01-01

    BACKGROUND:Both animal experiments and clinical studies have shown that basic fibroblast growth factor(bFGF)and danshen(Salvia miltiorrhiza)can exhibit protective effects on ischemia-reperfusion cerebral injury.OBJECTIVE:To test whether bFGF and danshen can protect cerebral injury induced by exposure to repeated,high,positive acceleration(+Gz)in an animal model and to analyze the possible mechanisms.DESIGN,TIME AND SETTING:Randomized controlled animal study.The experiment was performed at the Research Center for Molecular Biology,Air-force General Hospital of Chinese PLA from April to August 2000.MATERIALS:A total of 20 clean grade,healthy,Sprague Dawley rats of both genders,weighing(200±15)g,were provided by our experimental animal center.Rats were randomly divided into 5 groups:the control group,+Gz exposure group,bFGF group,danshen group,and saline group,with 4 animals per group.bFGF(Beijing Bailuyuan Biotechnology Co.Ltd.)and danshen solution(Shanghai Zhongxi Pharmaceutical Co.Ltd.)were used.METHODS:All rats were fixed on a rotary arm of a centrifugal apparams(2 m in radius)with their heads oriented towards the center of the apparatus.Except for rats in the control group.the value of+Gz exposure was+14 Gz with an acceleration rate of 1.5 G/s.The peak force lasted for 45 seconds.+Gz exposure was performed three times with intervals of 30 minutes.Rats in the control group received the same+Gz procedure,but the G value was+1 Gz.Rats in bFGF group and danshen group were intraperitoneally injected with 100 μg/kg bFGF or 15 g/kg danshen solution,respectively,at 30 minutes prior to centrifugation and immediately after tentrifugation.Rats in saline group were injected with the same volume of saline.Six hours after exposure,rats were decapitated.One hemisphere was preserved in liquid nitrogen for RNA extraction and the other was processed for apoptosis detection.MAIN OUTCOME MEASURES:mRNA levels of bcl-2 and p53 were measured by semi-quantitative reverse

  19. Exogenous endothelial cells as accelerators of hematopoietic reconstitution

    Directory of Open Access Journals (Sweden)

    Mizer J

    2012-11-01

    Full Text Available Abstract Despite the successes of recombinant hematopoietic-stimulatory factors at accelerating bone marrow reconstitution and shortening the neutropenic period post-transplantation, significant challenges remain such as cost, inability to reconstitute thrombocytic lineages, and lack of efficacy in conditions such as aplastic anemia. A possible means of accelerating hematopoietic reconstitution would be administration of cells capable of secreting hematopoietic growth factors. Advantages of this approach would include: a ability to regulate secretion of cytokines based on biological need; b long term, localized production of growth factors, alleviating need for systemic administration of factors that possess unintended adverse effects; and c potential to actively repair the hematopoietic stem cell niche. Here we overview the field of hematopoietic growth factors, discuss previous experiences with mesenchymal stem cells (MSC in accelerating hematopoiesis, and conclude by putting forth the rationale of utilizing exogenous endothelial cells as a novel cellular therapy for acceleration of hematopoietic recovery.

  20. SPS accelerating cavity

    CERN Multimedia

    1980-01-01

    One of the SPS acceleration cavities (200 MHz, travelling wave structure). On the ceiling one sees the coaxial transmission line which feeds the power from the amplifier, located in a surface building above, to the upstream end of the cavity. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8104138, 8302397.

  1. Prospects for Accelerator Technology

    Science.gov (United States)

    Todd, Alan

    2011-02-01

    Accelerator technology today is a greater than US$5 billion per annum business. Development of higher-performance technology with improved reliability that delivers reduced system size and life cycle cost is expected to significantly increase the total accelerator technology market and open up new application sales. Potential future directions are identified and pitfalls in new market penetration are considered. Both of the present big market segments, medical radiation therapy units and semiconductor ion implanters, are approaching the "maturity" phase of their product cycles, where incremental development rather than paradigm shifts is the norm, but they should continue to dominate commercial sales for some time. It is anticipated that large discovery-science accelerators will continue to provide a specialty market beset by the unpredictable cycles resulting from the scale of the projects themselves, coupled with external political and economic drivers. Although fraught with differing market entry difficulties, the security and environmental markets, together with new, as yet unrealized, industrial material processing applications, are expected to provide the bulk of future commercial accelerator technology growth.

  2. The CERN accelerator complex

    CERN Multimedia

    De Melis, Cinzia

    2016-01-01

    The LHC is the last ring (dark blue line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

  3. Atmospheric and accelerator neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoichiro [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo Higashi-Mozumi, Kamioka, Hida-City, Gifu 506-1205 (Japan)

    2006-05-15

    Results from the atmospheric neutrino measurements are presented. Evidence for the {nu}{sub {tau}} appearance in the atmospheric neutrino events was shown by statistical methods. The long baseline oscillation experiment using man-made neutrinos has confirmed the atmospheric neutrino oscillation. The future accelerator experiments are briefly discussed.

  4. Acceleration and Special Relativity

    CERN Document Server

    Yahalomi, E M

    2000-01-01

    The integration of acceleration over time before reaching the uniformvelocity turns out to be the source of all the special relativity effects. Itexplains physical phenomena like clocks comparisons. The equations forspace-time, mass and energy are presented. This phenomenon complements theexplanation for the twins paradox. A Universal reference frame is obtained.

  5. The CERN Accelerator School

    CERN Multimedia

    2016-01-01

      Introduction to accelerator physics This course will take place in Istanbul, Turkey, from 18 to 30 September 2016. It is now open for registration, and further information can be found here: http://cas.web.cern.ch/cas/Turkey-2016/Turkey-advert.html

  6. The CERN Accelerator School

    CERN Multimedia

    2016-01-01

    Introduction to accelerator physics This course will take place in Budapest, Hungary, from 2 to 14 October 2016. It is now open for registration and further information can be found at: http://cas.web.cern.ch/cas/Hungary2016/Hungary-advert.html and http://indico.cern.ch/event/532397/.

  7. The CERN accelerator complex

    CERN Multimedia

    Haffner, Julie

    2013-01-01

    The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

  8. The CERN accelerator complex

    CERN Multimedia

    Christiane Lefèvre

    2008-01-01

    The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

  9. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    One of the SPS accelerating cavities (200 MHz, travelling wave structure). The power that is fed into the upstream end of the cavity is extracted at the downstream end and sent into a dump load. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8011289, 8302397.

  10. Combined generating-accelerating buncher for compact linear accelerators

    Science.gov (United States)

    Savin, E. A.; Matsievskiy, S. V.; Sobenin, N. P.; Sokolov, I. D.; Zavadtsev, A. A.

    2016-09-01

    Described in the previous article [1] method of the power extraction from the modulated electron beam has been applied to the compact standing wave electron linear accelerator feeding system, which doesnt require any connection waveguides between the power source and the accelerator itself [2]. Generating and accelerating bunches meet in the hybrid accelerating cell operating at TM020 mode, thus the accelerating module is placed on the axis of the generating module, which consists from the pulsed high voltage electron sources and electrons dumps. This combination makes the accelerator very compact in size which is very valuable for the modern applications such as portable inspection sources. Simulations and geometry cold tests are presented.

  11. Neurodegeneration in accelerated aging.

    Science.gov (United States)

    Scheibye-Knudsen, Moren

    2016-11-01

    The growing proportion of elderly people represents an increasing economic burden, not least because of age-associated diseases that pose a significant cost to the health service. Finding possible interventions to age-associated disorders therefore have wide ranging implications. A number of genetically defined accelerated aging diseases have been characterized that can aid in our understanding of aging. Interestingly, all these diseases are associated with defects in the maintenance of our genome. A subset of these disorders, Cockayne syndrome, Xeroderma pigmentosum group A and ataxia-telangiectasia, show neurological involvement reminiscent of what is seen in primary human mitochondrial diseases. Mitochondria are the power plants of the cells converting energy stored in oxygen, sugar, fat, and protein into ATP, the energetic currency of our body. Emerging evidence has linked this organelle to aging and finding mitochondrial dysfunction in accelerated aging disorders thereby strengthens the mitochondrial theory of aging. This theory states that an accumulation of damage to the mitochondria may underlie the process of aging. Indeed, it appears that some accelerated aging disorders that show neurodegeneration also have mitochondrial dysfunction. The mitochondrial alterations may be secondary to defects in nuclear DNA repair. Indeed, nuclear DNA damage may lead to increased energy consumption, alterations in mitochondrial ATP production and defects in mitochondrial recycling, a term called mitophagy. These changes may be caused by activation of poly-ADP-ribose-polymerase 1 (PARP1), an enzyme that responds to DNA damage. Upon activation PARP1 utilizes key metabolites that attenuate pathways that are normally protective for the cell. Notably, pharmacological inhibition of PARP1 or reconstitution of the metabolites rescues the changes caused by PARP1 hyperactivation and in many cases reverse the phenotypes associated with accelerated aging. This implies that modulation

  12. Transforming Growth Factor β-1 (TGF-β1) Is a Serum Biomarker of Radiation Induced Fibrosis in Patients Treated With Intracavitary Accelerated Partial Breast Irradiation: Preliminary Results of a Prospective Study

    Energy Technology Data Exchange (ETDEWEB)

    Boothe, Dustin L. [Weill Cornell Medical College of Cornell University, New York, New York (United States); Coplowitz, Shana [Department of Radiation Oncology, Stich Radiation Center, Weill Cornell Medical College of Cornell University, New York, New York (United States); Greenwood, Eleni [Weill Cornell Medical College of Cornell University, New York, New York (United States); Barney, Christian L. [Department of Radiation Oncology, Ohio State University, Columbus, Ohio (United States); Christos, Paul J. [Division of Biostatistics and Epidemiology, Department of Public Health, Weill Cornell Medical College of Cornell University, New York, New York (United States); Parashar, Bhupesh; Nori, Dattatreyudu; Chao, K. S. Clifford [Department of Radiation Oncology, Stich Radiation Center, Weill Cornell Medical College of Cornell University, New York, New York (United States); Wernicke, A. Gabriella, E-mail: gaw9008@med.cornell.edu [Department of Radiation Oncology, Stich Radiation Center, Weill Cornell Medical College of Cornell University, New York, New York (United States)

    2013-12-01

    Purpose: To examine a relationship between serum transforming growth factor β -1 (TGF-β1) values and radiation-induced fibrosis (RIF). Methods and Materials: We conducted a prospective analysis of the development of RIF in 39 women with American Joint Committee on Cancer stage 0-I breast cancer treated with lumpectomy and accelerated partial breast irradiation via intracavitary brachytherapy (IBAPBI). An enzyme-linked immunoassay (Quantikine, R and D, Minneapolis, MN) was used to measure serum TGF-β1 before surgery, before IBAPBI, and during IBAPBI. Blood samples for TGF-β1 were also collected from 15 healthy, nontreated women (controls). The previously validated tissue compliance meter (TCM) was used to objectively assess RIF. Results: The median time to follow-up for 39 patients was 44 months (range, 5-59 months). RIF was graded by the TCM scale as 0, 1, 2, and 3 in 5 of 20 patients (25%), 6 of 20 patients (30%), 5 of 20 patients (25%), and 4 of 20 patients (20%), respectively. The mean serum TGF-β1 values were significantly higher in patients before surgery than in disease-free controls, as follows: all cancer patients (30,201 ± 5889 pg/mL, P=.02); patients with any type of RIF (32,273 ± 5016 pg/mL, P<.0001); and women with moderate to severe RIF (34,462 ± 4713 pg/mL, P<0.0001). Patients with moderate to severe RIF had significantly elevated TGF-β1 levels when compared with those with none to mild RIF before surgery (P=.0014) during IBAPBI (P≤0001), and the elevation persisted at 6 months (P≤.001), 12 months (P≤.001), 18 months (P≤.001), and 24 months (P=.12). A receiver operating characteristic (ROC) curve of TGF-β1 values predicting moderate to severe RIF was generated with an area under the curve (AUC){sub ROC} of 0.867 (95% confidence interval 0.700-1.000). The TGF-β1 threshold cutoff was determined to be 31,000 pg/mL, with associated sensitivity and specificity of 77.8% and 90.0%, respectively. Conclusions: TGF-β1 levels correlate with

  13. Ponderomotive Acceleration in Coronal Loops

    CERN Document Server

    Dahlburg, R B; Taylor, B D; Obenschain, K

    2016-01-01

    Ponderomotive acceleration has been asserted to be a cause of the First Ionization Potential (FIP) effect, the by now well known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a "byproduct" of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of a coronal loops with an axial magnetic field from 0.005 Teslas to 0.02 Teslas and lengths from 25000 km to 75000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets...

  14. Nonlinear dynamics in particle accelerators

    CERN Document Server

    Dilão, Rui

    1996-01-01

    This book is an introductory course to accelerator physics at the level of graduate students. It has been written for a large audience which includes users of accelerator facilities, accelerator physicists and engineers, and undergraduates aiming to learn the basic principles of construction, operation and applications of accelerators.The new concepts of dynamical systems developed in the last twenty years give the theoretical setting to analyse the stability of particle beams in accelerator. In this book a common language to both accelerator physics and dynamical systems is integrated and dev

  15. Dynamics of electron acceleration in laser-driven wakefields. Acceleration limits and asymmetric plasma waves

    Energy Technology Data Exchange (ETDEWEB)

    Popp, Antonia

    2011-12-16

    The experiments presented in this thesis study several aspects of electron acceleration in a laser-driven plasma wave. High-intensity lasers can efficiently drive a plasma wave that sustains electric fields on the order of 100 GV/m. Electrons that are trapped in this plasma wave can be accelerated to GeV-scale energies. As the accelerating fields in this scheme are 3-4 orders of magnitude higher than in conventional radio-frequency accelerators, the necessary acceleration distance can be reduced by the same factor, turning laser-wakefield acceleration (LWFA) into a promising compact, and potentially cheaper, alternative. However, laser-accelerated electron bunches have not yet reached the parameter standards of conventional accelerators. This work will help to gain better insight into the acceleration process and to optimize the electron bunch properties. The 25 fs, 1.8 J-pulses of the ATLAS laser at the Max-Planck-Institute of Quantum Optics were focused into a steady-state flow gas cell. This very reproducible and turbulence-free gas target allows for stable acceleration of electron bunches. Thus the sensitivity of electron parameters to subtle changes of the experimental setup could be determined with meaningful statistics. At optimized experimental parameters, electron bunches of {approx}50 pC total charge were accelerated to energies up to 450 MeV with a divergence of {approx}2 mrad FWHM. As, in a new design of the gas cell, its length can be varied from 2 to 14 mm, the electron bunch energy could be evaluated after different acceleration distances, at two different electron densities. From this evolution important acceleration parameters could be extracted. At an electron density of 6.43. 10{sup 18} cm{sup -3} the maximum electric field strength in the plasma wave was determined to be {approx}160 GV/m. The length after which the relativistic electrons outrun the accelerating phase of the electric field and are decelerated again, the so-called dephasing length

  16. Mass spectrometry with accelerators.

    Science.gov (United States)

    Litherland, A E; Zhao, X-L; Kieser, W E

    2011-01-01

    As one in a series of articles on Canadian contributions to mass spectrometry, this review begins with an outline of the history of accelerator mass spectrometry (AMS), noting roles played by researchers at three Canadian AMS laboratories. After a description of the unique features of AMS, three examples, (14)C, (10)Be, and (129)I are given to illustrate the methods. The capabilities of mass spectrometry have been extended by the addition of atomic isobar selection, molecular isobar attenuation, further ion acceleration, followed by ion detection and ion identification at essentially zero dark current or ion flux. This has been accomplished by exploiting the techniques and accelerators of atomic and nuclear physics. In 1939, the first principles of AMS were established using a cyclotron. In 1977 the selection of isobars in the ion source was established when it was shown that the (14)N(-) ion was very unstable, or extremely difficult to create, making a tandem electrostatic accelerator highly suitable for assisting the mass spectrometric measurement of the rare long-lived radioactive isotope (14)C in the environment. This observation, together with the large attenuation of the molecular isobars (13)CH(-) and (12)CH 2(-) during tandem acceleration and the observed very low background contamination from the ion source, was found to facilitate the mass spectrometry of (14)C to at least a level of (14)C/C ~ 6 × 10(-16), the equivalent of a radiocarbon age of 60,000 years. Tandem Accelerator Mass Spectrometry, or AMS, has now made possible the accurate radiocarbon dating of milligram-sized carbon samples by ion counting as well as dating and tracing with many other long-lived radioactive isotopes such as (10)Be, (26)Al, (36)Cl, and (129)I. The difficulty of obtaining large anion currents with low electron affinities and the difficulties of isobar separation, especially for the heavier mass ions, has prompted the use of molecular anions and the search for alternative

  17. Selective Acceleration in Impulsive Solar Flares

    Institute of Scientific and Technical Information of China (English)

    王德焴

    2001-01-01

    A plasma acceleration mechanism is proposed to explain the dramatic enhancement in the ratio of 3 He/4He, (enhancement factor 102 - 103) observed in solar 3He-rich flares. Considering that coronal plasma is mainly composed of hydrogen and helium ions, the hydrogen ion-helium ion hybrid waves and quasi-perpendicular waves can be excited by energetic electron beam during the impulsive solarflares. The frequencies of these waves are close to the 3He++ ion gyrofrequency, but far from the 4He++ ion gyrofrequency. Most of these waves are selectively absorbed by 3He ions. These preheated 3He ions can be successively stochastic accelerated by Alfvén turbulence, when their velocities are larger than the local Alfvén velocity. It makes the ratio of 3He/4He dramatically enhanced and the acceleration energy spectrum of 3He ions forms a power-law distribution during the impulsive solar flares.

  18. Cosmic acceleration from interaction of ordinary fluids

    CERN Document Server

    Pinto-Neto, Nelson

    2007-01-01

    Cosmological models with two interacting fluids, each satisfying the strong energy condition, are studied in the framework of classical General Relativity. If the interactions are phenomenologically described by a power law in the scale factor, the two initial interacting fluids can be equivalently substituted by two non interacting effective fluids, where one of them may violate the strong energy condition and/or have negative energy density. Analytical solutions of the Friedmann equations of this general setting are obtained and studied. One may have, depending on the scale where the interaction becomes important, non singular universes with early accelerated phase, or singular models with transition from decelerated to accelerated expansion at large scales. Among the first, there are bouncing models where contraction is stopped by the interaction. In the second case, one obtains dark energy expansion rates without dark energy, like $\\Lambda$CDM or phantomic accelerated expansions without cosmological const...

  19. Does electromagnetic radiation accelerate galactic cosmic rays

    Science.gov (United States)

    Eichler, D.

    1977-01-01

    The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.

  20. Influence of spatiotemporal coupling on the capture-and-acceleration-scenario vacuum electron acceleration by ultrashort pulsed laser beam

    Institute of Scientific and Technical Information of China (English)

    Lu Da-Quan; Qian Lie-Jia; Li Yong-Zhong; Fan Dian-Yuan

    2007-01-01

    This paper investigates the properties of the ultrashort pulsed beam aimed to the capture-and-acceleration-scenario(CAS) vacuum electron acceleration. The result shows that the spatiotemporal distribution of the phase velocity, the longitudinal component of the electric field and the acceleration quality factor are qualitatively similar to that of the continuous-wave Gaussian beam, and are slightly influenced by the spatiotemporal coupling of the ultrashort pulsed beam. When the pulse is compressed to an ultrashort one in which the pulse duration TFWHM < 5T0, the variation of the maximum net energy gain due to the carrier-envelope phase is a crucial disadvantage in the CAS acceleration process.

  1. Born Reciprocity and Cosmic Accelerations

    CERN Document Server

    Bolognesi, S

    2015-01-01

    The trans-Planckian theory is a model that realizes concretely the Born reciprocity idea, which is the postulate of absolute equivalence between coordinate $x$ and momenta $p$. This model is intrinsically global, and thus it is naturally implemented in a cosmological setting. Cosmology and Born reciprocity are made for each other. Inflation provides the essential mechanism to suppress the terms coming from the dual part of the action. The trans-Planckian theory, on the other hand, provides an explanation for the accelerated periods of the universe scale factor, both the inflationary period and the present period dominated by dark energy. All of this is possible just considering a simple model that contains gravity, one gauge field plus one matter field (to be identified with dark matter) together with the reciprocity principle.

  2. Acceleration of microparticle

    CERN Document Server

    Shibata, H

    2002-01-01

    A microparticle (dust) ion source has been installed at the high voltage terminal of the 3.75 MV single ended Van de Graaff electrostatic accelerator and a beam line for microparticle experiments has been build at High Fluence Irradiation Facility (HIT) of Research Center for Nuclear Science and Technology, the University of Tokyo. Microparticle acceleration has been successful in obtaining expected velocities of 1-20 km/s or more for micron or submicron sized particles. Development of in situ dust detectors and analyzers on board satellites and spacecraft in the expected mass and velocity range of micrometeoroids and investigation of hypervelocity impact phenomena by using time of flight mass spectrometry, impact flash or luminescence measurement and scanning electron or laser microscope observation for metals, ceramics, polymers and semiconductors bombarded by micron-sized particles were started three years ago. (author)

  3. Particle accelerator physics

    CERN Document Server

    Wiedemann, Helmut

    2015-01-01

    This book by Helmut Wiedemann is a well-established, classic text, providing an in-depth and comprehensive introduction to the field of high-energy particle acceleration and beam dynamics. The present 4th edition has been significantly revised, updated and expanded. The newly conceived Part I is an elementary introduction to the subject matter for undergraduate students. Part II gathers the basic tools in preparation of a more advanced treatment, summarizing the essentials of electrostatics and electrodynamics as well as of particle dynamics in electromagnetic fields. Part III is an extensive primer in beam dynamics, followed, in Part IV, by an introduction and description of the main beam parameters and including a new chapter on beam emittance and lattice design. Part V is devoted to the treatment of perturbations in beam dynamics. Part VI then discusses the details of charged particle acceleration. Parts VII and VIII introduce the more advanced topics of coupled beam dynamics and describe very intense bea...

  4. SUPERDIFFUSIVE SHOCK ACCELERATION

    Energy Technology Data Exchange (ETDEWEB)

    Perri, S.; Zimbardo, G. [Dipartimento di Fisica, Universita della Calabria, Ponte P. Bucci Cubo 31C, I-87036 Rende (Italy)

    2012-05-10

    The theory of diffusive shock acceleration is extended to the case of superdiffusive transport, i.e., when the mean square deviation grows proportionally to t{sup {alpha}}, with {alpha} > 1. Superdiffusion can be described by a statistical process called Levy random walk, in which the propagator is not a Gaussian but it exhibits power-law tails. By using the propagator appropriate for Levy random walk, it is found that the indices of energy spectra of particles are harder than those obtained where a normal diffusion is envisaged, with the spectral index decreasing with the increase of {alpha}. A new scaling for the acceleration time is also found, allowing substantially shorter times than in the case of normal diffusion. Within this framework we can explain a number of observations of flat spectra in various astrophysical and heliospheric contexts, for instance, for the Crab Nebula and the termination shock of the solar wind.

  5. Accelerating QDP++ using GPUs

    CERN Document Server

    Winter, Frank

    2011-01-01

    Graphic Processing Units (GPUs) are getting increasingly important as target architectures in scientific High Performance Computing (HPC). NVIDIA established CUDA as a parallel computing architecture controlling and making use of the compute power of GPUs. CUDA provides sufficient support for C++ language elements to enable the Expression Template (ET) technique in the device memory domain. QDP++ is a C++ vector class library suited for quantum field theory which provides vector data types and expressions and forms the basis of the lattice QCD software suite Chroma. In this work accelerating QDP++ expression evaluation to a GPU was successfully implemented leveraging the ET technique and using Just-In-Time (JIT) compilation. The Portable Expression Template Engine (PETE) and the C API for CUDA kernel arguments were used to build the bridge between host and device memory domains. This provides the possibility to accelerate Chroma routines to a GPU which are typically not subject to special optimisation. As an ...

  6. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  7. Hardware Accelerated Simulated Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Laney, D; Callahan, S; Max, N; Silva, C; Langer, S; Frank, R

    2005-04-12

    We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32 bit floating point texture capabilities to obtain validated solutions to the radiative transport equation for X-rays. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedra that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester. We show that the hardware accelerated solution is faster than the current technique used by scientists.

  8. Accelerators for Cancer Therapy

    Science.gov (United States)

    Lennox, Arlene J.

    2000-05-30

    The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy.

  9. Accelerated Parallel Texture Optimization

    Institute of Scientific and Technical Information of China (English)

    Hao-Da Huang; Xin Tong; Wen-Cheng Wang

    2007-01-01

    Texture optimization is a texture synthesis method that can efficiently reproduce various features of exemplar textures. However, its slow synthesis speed limits its usage in many interactive or real time applications. In this paper, we propose a parallel texture optimization algorithm to run on GPUs. In our algorithm, k-coherence search and principle component analysis (PCA) are used for hardware acceleration, and two acceleration techniques are further developed to speed up our GPU-based texture optimization. With a reasonable precomputation cost, the online synthesis speed of our algorithm is 4000+ times faster than that of the original texture optimization algorithm and thus our algorithm is capable of interactive applications. The advantages of the new scheme are demonstrated by applying it to interactive editing of flow-guided synthesis.

  10. NEW ACCELERATION METHODS

    Energy Technology Data Exchange (ETDEWEB)

    Sessler, A.M.

    1984-07-01

    But a glance at the Livingston chart, Fig. 1, of accelerator particle energy as a function of time shows that the energy has steadily, exponentially, increased. Equally significant is the fact that this increase is the envelope of diverse technologies. If one is to stay on, or even near, the Livingston curve in future years then new acceleration techniques need to be developed. What are the new acceleration methods? In these two lectures I would like to sketch some of these new ideas. I am well aware that they will probably not result in high energy accelerators within this or the next decade, but conversely, it is likely that these ideas will form the basis for the accelerators of the next century. Anyway, the ideas are stimulating and suffice to show that accelerator physicists are not just 'engineers', but genuine scientists deserving to be welcomed into the company of high energy physicists. I believe that outsiders will find this field surprisingly fertile and, certainly fun. To put it more personally, I very much enjoy working in this field and lecturing on it. There are a number of review articles which should be consulted for references to the original literature. In addition there are three books on the subject. Given this material, I feel free to not completely reference the material in the remainder of this article; consultation of the review articles and books will be adequate as an introduction to the literature for references abound (hundreds are given). At last, by way of introduction, I should like to quote from the end of Ref. 2 for I think the remarks made there are most germane. Remember that the talk was addressed to accelerator physicists: 'Finally, it is often said, I think by physicists who are not well-informed, that accelerator builders have used up their capital and now are bereft of ideas, and as a result, high energy physics will eventually--rather soon, in fact--come to a halt. After all, one can't build too many

  11. Accelerated plate tectonics.

    Science.gov (United States)

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

  12. Future Accelerator Magnet Needs

    CERN Document Server

    Devred, Arnaud; Yamamoto, A

    2005-01-01

    Superconducting magnet technology is continually evolving in order to meet the demanding needs of new accelerators and to provide necessary upgrades for existing machines. A variety of designs are now under development, including high fields and gradients, rapid cycling and novel coil configurations. This paper presents a summary of R&D programs in the EU, Japan and the USA. A performance comparison between NbTi and Nb3Sn along with fabrication and cost issues are also discussed.

  13. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  14. Tractor accelerated test on test rig

    Directory of Open Access Journals (Sweden)

    M. Mattetti

    2013-09-01

    Full Text Available The experimental tests performed to validate a tractor prototype before its production, need a substantial financial and time commitment. The tests could be reduced using accelerated tests able to reproduce on the structural part of the tractor, the same damage produced on the tractor during real life in a reduced time. These tests were usually performed reproducing a particular harsh condition a defined number of times, as for example using a bumpy road on track to carry out the test in any weather condition. Using these procedures the loads applied on the tractor structure are different with respect to those obtained during the real use, with the risk to apply loads hard to find in reality. Recently it has been demonstrated how, using the methodologies designed for cars, it is possible to also expedite the structural tests for tractors. In particular, automotive proving grounds were recently successfully used with tractors to perform accelerated structural tests able to reproduce the real use of the machine with an acceleration factor higher than that obtained with the traditional methods. However, the acceleration factor obtained with a tractor on proving grounds is in any case reduced due to the reduced speed of the tractors with respect to cars. In this context, the goal of the paper is to show the development of a methodology to perform an accelerated structural test on a medium power tractor using a 4 post test rig. In particular, several proving ground testing conditions have been performed to measure the loads on the tractor. The loads obtained were then edited to remove the not damaging portion of signals, and finally the loads obtained were reproduced in a 4 post test rig. The methodology proposed could be a valid alternative to the use of a proving ground to reproduce accelerated structural tests on tractors.

  15. Accelerator mass spectrometry.

    Science.gov (United States)

    Hellborg, Ragnar; Skog, Göran

    2008-01-01

    In this overview the technique of accelerator mass spectrometry (AMS) and its use are described. AMS is a highly sensitive method of counting atoms. It is used to detect very low concentrations of natural isotopic abundances (typically in the range between 10(-12) and 10(-16)) of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the use of smaller samples (mg and even sub-mg size) and shorter measuring times (less than 1 hr). The equipment used for AMS is almost exclusively based on the electrostatic tandem accelerator, although some of the newest systems are based on a slightly different principle. Dedicated accelerators as well as older "nuclear physics machines" can be found in the 80 or so AMS laboratories in existence today. The most widely used isotope studied with AMS is 14C. Besides radiocarbon dating this isotope is used in climate studies, biomedicine applications and many other fields. More than 100,000 14C samples are measured per year. Other isotopes studied include 10Be, 26Al, 36Cl, 41Ca, 59Ni, 129I, U, and Pu. Although these measurements are important, the number of samples of these other isotopes measured each year is estimated to be less than 10% of the number of 14C samples.

  16. Accelerated Profile HMM Searches.

    Directory of Open Access Journals (Sweden)

    Sean R Eddy

    2011-10-01

    Full Text Available Profile hidden Markov models (profile HMMs and probabilistic inference methods have made important contributions to the theory of sequence database homology search. However, practical use of profile HMM methods has been hindered by the computational expense of existing software implementations. Here I describe an acceleration heuristic for profile HMMs, the "multiple segment Viterbi" (MSV algorithm. The MSV algorithm computes an optimal sum of multiple ungapped local alignment segments using a striped vector-parallel approach previously described for fast Smith/Waterman alignment. MSV scores follow the same statistical distribution as gapped optimal local alignment scores, allowing rapid evaluation of significance of an MSV score and thus facilitating its use as a heuristic filter. I also describe a 20-fold acceleration of the standard profile HMM Forward/Backward algorithms using a method I call "sparse rescaling". These methods are assembled in a pipeline in which high-scoring MSV hits are passed on for reanalysis with the full HMM Forward/Backward algorithm. This accelerated pipeline is implemented in the freely available HMMER3 software package. Performance benchmarks show that the use of the heuristic MSV filter sacrifices negligible sensitivity compared to unaccelerated profile HMM searches. HMMER3 is substantially more sensitive and 100- to 1000-fold faster than HMMER2. HMMER3 is now about as fast as BLAST for protein searches.

  17. Optimizing accelerator technology

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    A new EU-funded research and training network, oPAC, is bringing together 22 universities, research centres and industry partners to optimize particle accelerator technology. CERN is one of the network’s main partners and will host 5 early-stage researchers in the BE department.   A diamond detector that will be used for novel beam diagnostics applications in the oPAC project based at CIVIDEC. (Image courtesy of CIVIDEC.) As one of the largest Marie Curie Initial Training Networks ever funded by the EU – to the tune of €6 million – oPAC extends well beyond the particle physics community. “Accelerator physics has become integral to research in almost every scientific discipline – be it biology and life science, medicine, geology and material science, or fundamental physics,” explains Carsten P. Welsch, oPAC co-ordinator based at the University of Liverpool. “By optimizing the operation of accelerators, all of these...

  18. Berkeley Proton Linear Accelerator

    Science.gov (United States)

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

  19. French nuclear physics accelerator opens

    Science.gov (United States)

    Dumé, Belle

    2016-12-01

    A new €140m particle accelerator for nuclear physics located at the French Large Heavy Ion National Accelerator (GANIL) in Caen was inaugurated last month in a ceremony attended by French president François Hollande.

  20. Periodic Relativity: Deflection of Light, Acceleration, Rotation Curves

    Directory of Open Access Journals (Sweden)

    Zaveri V. H.

    2015-01-01

    Full Text Available Vectorial analysis relating to derivation of deflection of light is presented. Curvilinear acceleration is distinguished from the Newtonian polar conic acceleration. The dif- ference between the two is due to the curvature term. Lorentz invariant expression for acceleration is derived. A physical theory of rotation curves of galaxies based on second solution to Einstein’s field equation is presented. Theory is applied to Milky Way, M31, NGC3198 and Solar system. Modified Kepler’s third law yields correct orbital periods of stars in a galaxy. Deviation factor in the line element of t he theory happens to be the ratio of the Newtonian gravitational acceleration to th e measured acceleration of the star in the galaxy. Therefore this deviation factor can replace the MOND function.

  1. Plasma accelerator experiments in Yugoslavia

    Science.gov (United States)

    Purić, J.; Astashynski, V. M.; Kuraica, M. M.; Dojčinovié, I. P.

    2002-12-01

    An overview is given of the results obtained in the Plasma Accelerator Experiments in Belgrade, using quasi-stationary high current plasma accelerators constructed within the framework of the Yugoslavia-Belarus Joint Project. So far, the following plasma accelerators have been realized: Magnetoplasma Compressor type (MPC); MPC Yu type; one stage Erosive Plasma Dynamic System (EPDS) and, in final stage of construction two stage Quasi-Stationary High Current Plasma Accelerator (QHPA).

  2. Accelerating in de Sitter spacetimes

    CERN Document Server

    Cotaescu, Ion I

    2014-01-01

    We propose a definition of uniform accelerated frames in de Sitter spacetimes exploiting the Nachtmann group theoretical method of introducing coordinates on these manifolds. Requiring the transformation between the static frame and the accelerated one to depend continuously on acceleration in order to recover the well-known Rindler approach in the flat limit, we obtain a result with a reasonable physical meaning.

  3. A Statistical Perspective on Highly Accelerated Testing

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward V. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use of highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning

  4. A Statistical Perspective on Highly Accelerated Testing.

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward V.

    2015-02-01

    Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use of highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning

  5. APT accelerator. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, G.; Rusthoi, D. [comp.] [ed.

    1995-03-01

    The Accelerator Production of Tritium (APT) project, sponsored by Department of Energy Defense Programs (DOE/DP), involves the preconceptual design of an accelerator system to produce tritium for the nation`s stockpile of nuclear weapons. Tritium is an isotope of hydrogen used in nuclear weapons, and must be replenished because of radioactive decay (its half-life is approximately 12 years). Because the annual production requirements for tritium has greatly decreased since the end of the Cold War, an alternative approach to reactors for tritium production, based on a linear accelerator, is now being seriously considered. The annual tritium requirement at the time this study was undertaken (1992-1993) was 3/8 that of the 1988 goal, usually stated as 3/8-Goal. Continued reduction in the number of weapons in the stockpile has led to a revised (lower) production requirement today (March, 1995). The production requirement needed to maintain the reduced stockpile, as stated in the recent Nuclear Posture Review (summer 1994) is approximately 3/16-Goal, half the previous level. The Nuclear Posture Review also requires that the production plant be designed to accomodate a production increase (surge) to 3/8-Goal capability within five years, to allow recovery from a possible extended outage of the tritium plant. A multi-laboratory team, collaborating with several industrial partners, has developed a preconceptual APT design for the 3/8-Goal, operating at 75% capacity. The team has presented APT as a promising alternative to the reactor concepts proposed for Complex-21. Given the requirements of a reduced weapons stockpile, APT offers both significant safety, environmental, and production-fexibility advantages in comparison with reactor systems, and the prospect of successful development in time to meet the US defense requirements of the 21st Century.

  6. Muon Acceleration - RLA and FFAG

    Energy Technology Data Exchange (ETDEWEB)

    Bogacz, Alex

    2011-10-01

    Various acceleration schemes for muons are presented. The overall goal of the acceleration systems: large acceptance acceleration to 25 GeV and 'beam shaping' can be accomplished by various fixed field accelerators at different stages. They involve three superconducting linacs: a single pass linear Pre-accelerator followed by a pair of multi-pass Recirculating Linear Accelerators (RLA) and finally a non-scaling FFAG ring. The present baseline acceleration scenario has been optimized to take maximum advantage of appropriate acceleration scheme at a given stage. The solenoid based Pre-accelerator offers very large acceptance and facilitates correction of energy gain across the bunch and significant longitudinal compression trough induced synchrotron motion. However, far off-crest acceleration reduces the effective acceleration gradient and adds complexity through the requirement of individual RF phase control for each cavity. The RLAs offer very efficient usage of high gradient superconducting RF and ability to adjust path-length after each linac pass through individual return arcs with uniformly periodic FODO optics suitable for chromatic compensation of emittance dilution with sextupoles. However, they require spreaders/recombiners switchyards at both linac ends and significant total length of the arcs. The non-scaling Fixed Field Alternating Gradient (FFAG) ring combines compactness with very large chromatic acceptance (twice the injection energy) and it allows for large number of passes through the RF (at least eight, possibly as high as 15).

  7. Hardware Accelerated Power Estimation

    CERN Document Server

    Coburn, Joel; Raghunathan, Anand

    2011-01-01

    In this paper, we present power emulation, a novel design paradigm that utilizes hardware acceleration for the purpose of fast power estimation. Power emulation is based on the observation that the functions necessary for power estimation (power model evaluation, aggregation, etc.) can be implemented as hardware circuits. Therefore, we can enhance any given design with "power estimation hardware", map it to a prototyping platform, and exercise it with any given test stimuli to obtain power consumption estimates. Our empirical studies with industrial designs reveal that power emulation can achieve significant speedups (10X to 500X) over state-of-the-art commercial register-transfer level (RTL) power estimation tools.

  8. 2014 CERN Accelerator Schools

    CERN Multimedia

    2014-01-01

    A specialised school on Power Converters will be held in Baden, Switzerland, from 7 to 14 May 2014. Please note that the deadline for applications is 7 FEBRUARY 2014. A course on Introduction to Accelerator Physics will be held in Prague, Czech Republic, from 31 August to 12 September 2014. Applications are now open for this school; the application deadline is 25 APRIL 2014. Further information on these schools and other CAS events can be found on the CAS website and on the Indico page. For further information please contact Barbara.strasser@cern.ch

  9. Accelerated Innovation Pilot

    Science.gov (United States)

    Davis, Jeffrey

    2012-01-01

    Opportunities: I. Engage NASA team (examples) a) Research and technology calls . provide suggestions to AES, HRP, OCT. b) Use NASA@Work to solicit other ideas; (possibly before R+D calls). II. Stimulate collaboration (examples) a) NHHPC. b) Wharton Mack Center for Technological Innovation (Feb 2013). c) International ] DLR ] :envihab (July 2013). d) Accelerated research models . NSF, Myelin Repair Foundation. III. Engage public Prizes (open platform: InnoCentive, yet2.com, NTL; Rice Business Plan, etc.) IV. Use same methods to engage STEM.

  10. Medical applications of accelerators

    CERN Document Server

    Rossi, Sandro

    1998-01-01

    At Present, about five thousands accelerators are devoted to biomedical applications. They are mainly used in radiotherapy, research and medical radioisotopes production. In this framework oncological hadron-therapy deserves particular attention since it represents a field in rapid evolution thanks to the joint efforts of laboratories with long experiences in particle physics. It is the case of CERN where the design of an optimised synchrotron for medical applications has been pursued. These lectures present these activities with particular attention to the new developments which are scientifically interesting and/or economically promising.

  11. Accelerating abelian gauge dynamics

    CERN Document Server

    Adler, Stephen Louis

    1991-01-01

    In this paper, we suggest a new acceleration method for Abelian gauge theories based on linear transformations to variables which weight all length scales equally. We measure the autocorrelation time for the Polyakov loop and the plaquette at β=1.0 in the U(1) gauge theory in four dimensions, for the new method and for standard Metropolis updates. We find a dramatic improvement for the new method over the Metropolis method. Computing the critical exponent z for the new method remains an important open issue.

  12. ACCELERATING NANO-TECHNOLOGICAL

    DEFF Research Database (Denmark)

    Jensen, Jens Stissing; Koch, Christian

    2007-01-01

    By viewing the construction industry as a technological innovation system (TIS) this paper discusses possible initiatives to accelerate nanotechnological innovations. The point of departure is a recent report on the application of nano-technology in the Danish construction industry, which concludes...... of the system are furthermore poorly equipped at identifying potentials within high-tech areas. In order to exploit the potentials of nano-technology it is thus argued that an alternative TIS needs to be established. Initiatives should identify and support “incubation rooms” or marked niches in order...

  13. Particle acceleration mechanisms

    CERN Document Server

    Petrosyan, V

    2008-01-01

    We review the possible mechanisms for production of non-thermal electrons which are responsible for non-thermal radiation in clusters of galaxies. Our primary focus is on non-thermal Bremsstrahlung and inverse Compton scattering, that produce hard X-ray emission. We briefly review acceleration mechanisms and point out that in most astrophysical situations, and in particular for the intracluster medium, shocks, turbulence and plasma waves play a crucial role. We consider two scenarios for production of non-thermal radiation. The first is hard X-ray emission due to non-thermal Bremsstrahlung by nonrelativistic particles. Non-thermal tails are produced by accelerating electrons from the background plasma with an initial Maxwellian distribution. However, these tails are accompanied by significant heating and they are present for a short time of <10^6 yr, which is also the time that the tail will be thermalised. Such non-thermal tails, even if possible, can only explain the hard X-ray but not the radio emission...

  14. Accelerator School Success

    CERN Multimedia

    2004-01-01

    Accelerator specialists don't grow on trees: training them is the job of the CERN Accelerator School (CAS). Group photo during visit to the Daresbury Laboratory. CAS and the CCLRC Daresbury Laboratory jointly organised a specialised school on Power Converters in Warrington, England from 12-18 May 2004. The last CAS Power Converter course was in 1990, so there was plenty of ground to cover. The challenging programme proposed a review of the state of the art and the latest developments in the field, including 30 hours of tuition. The school also included a visit to the CCLRC Daresbury laboratory, a one-day excursion to Liverpool and Chester and a themed (Welsh medieval) dinner at the school's closure. A record attendance of 91 students of more than 20 different nationalities included not only participants from Europe and North America but also from Armenia, Taiwan, India, Turkey, Iran and for the first time, fee-paying students from China and Australia. European industry showed a welcome and solid interest in...

  15. Scientific computing with multicore and accelerators

    CERN Document Server

    Kurzak, Jakub; Dongarra, Jack

    2010-01-01

    Dense Linear Algebra Implementing Matrix Multiplication on the Cell B.E, Wesley Alvaro, Jakub Kurzak, and Jack DongarraImplementing Matrix Factorizations on the Cell BE, Jakub Kurzak and Jack DongarraDense Linear Algebra for Hybrid GPU-Based Systems, Stanimire Tomov and Jack DongarraBLAS for GPUs, Rajib Nath, Stanimire Tomov, and Jack DongarraSparse Linear Algebra Sparse Matrix-Vector Multiplication on Multicore and Accelerators, Samuel Williams, Nathan B

  16. Acceleration in Linear and Circular Motion

    Science.gov (United States)

    Kellington, S. H.; Docherty, W.

    1975-01-01

    Describes the construction of a simple accelerometer and explains its use in demonstrating acceleration, deceleration, constant speed, measurement of acceleration, acceleration and the inclined plane and angular and radial acceleration. (GS)

  17. 2014 Joint International Accelerator School: Beam Loss and Accelerator Protection

    CERN Document Server

    JAS - Joint US-CERN-Japan-Russia Accelerator School

    2016-01-01

    Many particle accelerators operate with very high beam power and very high energy stored in particle beams as well as in magnet systems. In the future, the beam power in high intensity accelerators will further increase. The protection of the accelerator equipment from the consequences of uncontrolled release of the energy is essential. This was the motivation for organizing a first school on beam losses and accelerator protection (in general referred to as machine protection). During the school the methods and technologies to identify, mitigate, monitor and manage the technical risks associated with the operation of accelerators with high-power beams or subsystems with large stored energy were presented. At the completion of the school the participants should have been able to understand the physical phenomena that can damage machine subsystems or interrupt operations and to analyze an accelerator facility to produce a register of technical risks and the corresponding risk mitigation and management strategie...

  18. Investigation on laser accelerators. Plasma beat wave accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Akihiko; Miyamoto, Yasuaki; Hagiwara, Masayoshi; Suzuki, Mitsutoshi; Sudo, Osamu [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works

    1998-04-01

    Laser accelerator technology has characteristics of high energy, compact, short pulse and high luminescence{center_dot}low emittance. This means potential many applications in wide ranges of fields as well as high energy and nuclear physics. High power short laser pulses are injected to a plasma in the typical example of laser accelerators. Large electric fields are induced in the plasma. Electrons in the plasma are accelerated with the ponderomotive force of the electric field. The principles of interaction on beat wave, wakefield accelerators, inverse free electron laser and inverse Cherenkov radiation are briefly introduced. The overview of plasma beat wave accelerator study is briefly described on the programs at Chalk River Laboratories(Canada), UCLA(USA), Osaka Univ. (Japan) and Ecole Polytechnique (France). Issues of the plasma beat wave accelerator are discussed from the viewpoint of application. Existing laser technologies of CO{sub 2}, YAG and YFL are available for the present day accelerator technology. An acceleration length of beat wave interaction is limited due to its phase condition. Ideas on multi-staged acceleration using the phasing plasma fiber are introduced. (Y. Tanaka)

  19. CERN Accelerator School: Registration open for Advanced Accelerator Physics course

    CERN Multimedia

    2015-01-01

    Registration is now open for the CERN Accelerator School’s Advanced Accelerator Physics course to be held in Warsaw, Poland from 27 September to 9 October 2015.   The course will be of interest to physicists and engineers who wish to extend their knowledge of Accelerator Physics. The programme offers core lectures on accelerator physics in the mornings and a practical course with hands-on tuition in the afternoons.  Further information can be found at: http://cas.web.cern.ch/cas/Poland2015/Warsaw-advert.html http://indico.cern.ch/event/361988/

  20. CERN Accelerator School: Registration open for Advanced Accelerator Physics course

    CERN Multimedia

    2015-01-01

    Registration is now open for the CERN Accelerator School’s Advanced Accelerator Physics course to be held in Warsaw, Poland from 27 September to 9 October 2015.   The course will be of interest to physicists and engineers who wish to extend their knowledge of accelerator physics. The programme offers core lectures on accelerator physics in the mornings and a practical course with hands-on tuition in the afternoons.  Further information can be found at: http://cas.web.cern.ch/cas/Poland2015/Warsaw-advert.html http://indico.cern.ch/event/361988/

  1. Accelerated Chemical Reactions and Organic Synthesis in Leidenfrost Droplets.

    Science.gov (United States)

    Bain, Ryan M; Pulliam, Christopher J; Thery, Fabien; Cooks, R Graham

    2016-08-22

    Leidenfrost levitated droplets can be used to accelerate chemical reactions in processes that appear similar to reaction acceleration in charged microdroplets produced by electrospray ionization. Reaction acceleration in Leidenfrost droplets is demonstrated for a base-catalyzed Claisen-Schmidt condensation, hydrazone formation from precharged and neutral ketones, and for the Katritzky pyrylium into pyridinium conversion under various reaction conditions. Comparisons with bulk reactions gave intermediate acceleration factors (2-50). By keeping the volume of the Leidenfrost droplets constant, it was shown that interfacial effects contribute to acceleration; this was confirmed by decreased reaction rates in the presence of a surfactant. The ability to multiplex Leidenfrost microreactors, to extract product into an immiscible solvent during reaction, and to use Leidenfrost droplets as reaction vessels to synthesize milligram quantities of product is also demonstrated.

  2. Accelerated Life Test Design for Tractor Powertrain Front Axle

    Directory of Open Access Journals (Sweden)

    Ismail Azianti

    2016-01-01

    Full Text Available Accelerated Life Test (ALT has been applied in the manufacturing for many years due to rapid changing technologies, more complex products, speedier product development, and more demanding customer requirements. These reasons have pushed the manufacturers to acquire reliability information faster. ALT allows reducing the time needed to show the reliability of the product. The purpose of this study is to design accelerated life testing which involved determination of normal test time, acceleration factor, acceleration test time, and finally experimental setup. This case study provides the basis for ALT designs for the tractor front axle based on customer usage and field failure analysis, which were conducted to estimate the current reliability, especially on the B10 life during the operational stage of the product. The accelerated life test conducted has guaranteed the B10 life of 4,000 hours with 90% confidence level for lesser time needed for testing to show the reliability of the front axle assembly.

  3. Electrostatic accelerators fundamentals and applications

    CERN Document Server

    2005-01-01

    Electrostatic accelerators are an important and widespread subgroup within the broad spectrum of modern, large particle acceleration devices. They are specifically designed for applications that require high-quality ion beams in terms of energy stability and emittance at comparatively low energies (a few MeV). Their ability to accelerate virtually any kind of ion over a continuously tunable range of energies make them a highly versatile tool for investigations in many research fields including, but not limited to, atomic and nuclear spectroscopy, heavy ion reactions, accelerator mass spectroscopy as well as ion-beam analysis and modification. The book is divided into three parts. The first part concisely introduces the field of accelerator technology and techniques that emphasize their major modern applications. The second part treats the electrostatic accelerator per se: its construction and operational principles as well as its maintenance. The third part covers all relevant applications in which electrosta...

  4. Control problems in very large accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Crowley-Milling, M.C.

    1985-06-01

    There is no fundamental difference of kind in the control requirements between a small and a large accelerator since they are built of the same types of components, which individually have similar control inputs and outputs. The main difference is one of scale; the large machine has many more components of each type, and the distances involved are much greater. Both of these factors must be taken into account in determining the optimum way of carrying out the control functions. Small machines should use standard equipment and software for control as much as possible, as special developments for small quantities cannot normally be justified if all costs are taken into account. On the other hand, the very great number of devices needed for a large machine means that, if special developments can result in simplification, they may make possible an appreciable reduction in the control equipment costs. It is the purpose of this report to look at the special control problems of large accelerators, which the author shall arbitarily define as those with a length of circumference in excess of 10 km, and point out where special developments, or the adoption of developments from outside the accelerator control field, can be of assistance in minimizing the cost of the control system. Most of the first part of this report was presented as a paper to the 1985 Particle Accelerator Conference. It has now been extended to include a discussion on the special case of the controls for the SSC.

  5. Diffusive Shock Acceleration at Cosmological Shock Waves

    CERN Document Server

    Kang, Hyesung

    2012-01-01

    We reexamine nonlinear diffusive shock acceleration (DSA) at cosmological shocks in the large scale structure of the Universe, incorporating wave-particle interactions that are expected to operate in collisionless shocks. Adopting simple phenomenological models for magnetic field amplification (MFA) by cosmic-ray (CR) streaming instabilities and Alfv'enic drift, we perform kinetic DSA simulations for a wide range of sonic and Alfv'enic Mach numbers and evaluate the CR injection fraction and acceleration efficiency. In our DSA model the CR acceleration efficiency is determined mainly by the sonic Mach number Ms, while the MFA factor depends on the Alfv'enic Mach number and the degree of shock modification by CRs. We show that at strong CR modified shocks, if scattering centers drift with an effective Alfv'en speed in the amplified magnetic field, the CR energy spectrum is steepened and the acceleration efficiency is reduced significantly, compared to the cases without such effects. As a result, the postshock C...

  6. DIFFUSIVE SHOCK ACCELERATION AT COSMOLOGICAL SHOCK WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Ryu, Dongsu, E-mail: kang@uju.es.pusan.ac.kr, E-mail: ryu@canopus.cnu.ac.kr [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2013-02-10

    We reexamine nonlinear diffusive shock acceleration (DSA) at cosmological shocks in the large-scale structure of the universe, incorporating wave-particle interactions that are expected to operate in collisionless shocks. Adopting simple phenomenological models for magnetic field amplification (MFA) by cosmic-ray (CR) streaming instabilities and Alfvenic drift, we perform kinetic DSA simulations for a wide range of sonic and Alfvenic Mach numbers and evaluate the CR injection fraction and acceleration efficiency. In our DSA model, the CR acceleration efficiency is determined mainly by the sonic Mach number M{sub s} , while the MFA factor depends on the Alfvenic Mach number and the degree of shock modification by CRs. We show that at strong CR modified shocks, if scattering centers drift with an effective Alfven speed in the amplified magnetic field, the CR energy spectrum is steepened and the acceleration efficiency is reduced significantly, compared to the cases without such effects. As a result, the postshock CR pressure saturates roughly at {approx}20% of the shock ram pressure for strong shocks with M{sub s} {approx}> 10. In the test-particle regime (M{sub s} {approx}< 3), it is expected that the magnetic field is not amplified and the Alfvenic drift effects are insignificant, although relevant plasma physical processes at low Mach number shocks remain largely uncertain.

  7. HIGH ENERGY PARTICLE ACCELERATOR

    Science.gov (United States)

    Courant, E.D.; Livingston, M.S.; Snyder, H.S.

    1959-04-14

    An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.

  8. Hadron accelerators for radiotherapy

    Science.gov (United States)

    Owen, Hywel; MacKay, Ranald; Peach, Ken; Smith, Susan

    2014-04-01

    Over the last twenty years the treatment of cancer with protons and light nuclei such as carbon ions has moved from being the preserve of research laboratories into widespread clinical use. A number of choices now exist for the creation and delivery of these particles, key amongst these being the adoption of pencil beam scanning using a rotating gantry; attention is now being given to what technologies will enable cheaper and more effective treatment in the future. In this article the physics and engineering used in these hadron therapy facilities is presented, and the research areas likely to lead to substantive improvements. The wider use of superconducting magnets is an emerging trend, whilst further ahead novel high-gradient acceleration techniques may enable much smaller treatment systems. Imaging techniques to improve the accuracy of treatment plans must also be developed hand-in-hand with future sources of particles, a notable example of which is proton computed tomography.

  9. Dynamics of pyroelectric accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ghaderi, R.; Davani, F. Abbasi, E-mail: fabbasi@sbu.ac.ir [Radiation Application Department, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2015-01-26

    Pyroelectric crystals are used to produce high energy electron beams. We have derived a method to model electric potential generation on LiTaO{sub 3} crystal during heating cycle. In this method, effect of heat transfer on the potential generation is investigated by some experiments. In addition, electron emission from the crystal surface is modeled by measurements and analysis. These spectral data are used to present a dynamic equation of electric potential with respect to thickness of the crystal and variation of its temperature. The dynamic equation's results for different thicknesses are compared with measured data. As a result, to attain more energetic electrons, best thickness of the crystals could be extracted from the equation. This allows for better understanding of pyroelectric crystals and help to study about current and energy of accelerated electrons.

  10. Testing Gravity on Accelerators

    CERN Document Server

    Kalaydzhyan, Tigran

    2016-01-01

    Weak equivalence principle (WEP) is one of the cornerstones of the modern theories of gravity, stating that the trajectory of a freely falling test body is independent of its internal structure and composition. Even though WEP is known to be valid for the normal matter with a high precision, it has never been experimentally confirmed for relativistic matter and antimatter. We make an attempt to constrain possible deviations from WEP utilizing the modern accelerator technologies. We analyze the (absence of) vacuum Cherenkov radiation, photon decay, anomalous synchrotron losses and the Compton spectra to put limits on the isotropic Lorentz violation and further convert them to the constraints on the difference between the gravitational and inertial masses of the relativistic electrons/positrons. Our main result is the 0.1% limit on the mentioned difference.

  11. Acceleration of cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Berezhko, E [Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk (Russian Federation)], E-mail: berezhko@ikfia.ysn.ru

    2008-07-15

    Cosmic ray (CR) origin problem is briefly discussed. It is argued that CRs with energies up to 10{sup 17} eV are produced in galactic supernova remnants, whereas ultra high energy CRs are extragalactic. CR composition strongly changes within the transition from galactic to extragalactic CR component, therefore precise measurements of CR composition at energies 10{sup 17} - 10{sup 19} eV are needed for the reliable determination of this transition. The possible sources of extragalactic CRs are briefly discussed. It is argued that CR acceleration at the shock created by the expanding cocoons around active galactic nuclei has to be considered as a prime candidate for the sources of extragalactic CRs.

  12. SPS accelerating cavity

    CERN Multimedia

    1976-01-01

    The SPS started up with 2 accelerating cavities (each consisting of 5 tank sections) in LSS3. They have a 200 MHz travelling wave structure (see 7411032 and 7802190) and 750 kW of power is fed to each of the cavities from a 1 MW tetrode power amplifier, located in a surface building above, via a coaxial transmission line. Clemens Zettler, builder of the SPS RF system, is standing at the side of one of the cavities. In 1978 and 1979 another 2 cavities were added and entered service in 1980. These were part of the intensity improvement programme and served well for the new role of the SPS as proton-antiproton collider. See also 7411032, 8011289, 8104138, 8302397.

  13. Accelerators for Fusion Materials Testing

    Science.gov (United States)

    Knaster, Juan; Okumura, Yoshikazu

    Fusion materials research is a worldwide endeavor as old as the parallel one working toward the long term stable confinement of ignited plasma. In a fusion reactor, the preservation of the required minimum thermomechanical properties of the in-vessel components exposed to the severe irradiation and heat flux conditions is an indispensable factor for safe operation; it is also an essential goal for the economic viability of fusion. Energy from fusion power will be extracted from the 14 MeV neutron freed as a product of the deuterium-tritium fusion reactions; thus, this kinetic energy must be absorbed and efficiently evacuated and electricity eventually generated by the conventional methods of a thermal power plant. Worldwide technological efforts to understand the degradation of materials exposed to 14 MeV neutron fluxes >1018 m-2s-1, as expected in future fusion power plants, have been intense over the last four decades. Existing neutron sources can reach suitable dpa (“displacement-per-atom”, the figure of merit to assess materials degradation from being exposed to neutron irradiation), but the differences in the neutron spectrum of fission reactors and spallation sources do not allow one to unravel the physics and to anticipate the degradation of materials exposed to fusion neutrons. Fusion irradiation conditions can be achieved through Li (d, xn) nuclear reactions with suitable deuteron beam current and energy, and an adequate flowing lithium screen. This idea triggered in the late 1970s at Los Alamos National Laboratory (LANL) a campaign working toward the feasibility of continuous wave (CW) high current linacs framed by the Fusion Materials Irradiation Test (FMIT) project. These efforts continued with the Low Energy Demonstrating Accelerator (LEDA) (a validating prototype of the canceled Accelerator Production of Tritium (APT) project), which was proposed in 2002 to the fusion community as a 6.7MeV, 100mA CW beam injector for a Li (d, xn) source to bridge

  14. Project X: Accelerator Reference Design

    CERN Document Server

    Holmes, S D; Chase, B; Gollwitzer, K; Johnson, D; Kaducak, M; Klebaner, A; Kourbanis, I; Lebedev, V; Leveling, A; Li, D; Nagaitsev, S; Ostroumov, P; Pasquinelli, R; Patrick, J; Prost, L; Scarpine, V; Shemyakin, A; Solyak, N; Steimel, J; Yakovlev, V; Zwaska, R

    2013-01-01

    Part 1 of "Project X: Accelerator Reference Design, Physics Opportunities, Broader Impacts". Part 1 contains the volume Preface and a description of the conceptual design for a high-intensity proton accelerator facility being developed to support a world-leading program of Intensity Frontier physics over the next two decades at Fermilab. Subjects covered include performance goals, the accelerator physics design, and the technological basis for such a facility.

  15. NIIEFA accelerators for applied purposes

    Science.gov (United States)

    Vorogushin, M. F.; Strokach, A. P.; Filatov, O. G.

    2016-12-01

    Since the foundation of the institute, we have designed and delivered more than three hundred different accelerators to Russia and abroad: cyclotrons, linear accelerators, and neutron generators. The technical characteristics of our equipment makes it competitive on the international market. Here we present the application, main parameters, and status of accelerators manufactured by NIIEFA, as well as prospects for the development of electrophysical systems for applied purposes.

  16. Landing the uniformly accelerating observers

    OpenAIRE

    Rothenstein, Bernhard; Popescu, Stefan; Gruber, Ronald P.

    2006-01-01

    Observers of the uniformly accelerating observers or the observers who make up the system of uniformly accelerating observers reach the same velocity V at different times ti which depends on V and on theirs acceleration gi. Considering a platform that moves with constant velocity V, the observers can land smoothly on it. Their ages and locations in the inertial reference frame attached to the platform are reckoned and compared.

  17. Collective accelerator for electron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, R.J.

    1985-05-13

    A recent concept for collective acceleration and focusing of a high energy electron bunch is discussed, in the context of its possible applicability to large linear colliders in the TeV range. The scheme can be considered to be a member of the general class of two-beam accelerators, where a high current, low voltage beam produces the acceleration fields for a trailing high energy bunch.

  18. Thomas Precession by Uniform Acceleration

    CERN Document Server

    Pardy, Miroslav

    2015-01-01

    We determine the nonlinear transformations between coordinate systems which are mutually in a constant symmetrical accelerated motion. The maximal acceleration limit follows from the kinematical origin and it is an analogue of the maximal velocity in special relativity. We derive the dependence of mass, length, time, Doppler effect, Cherenkov effect and transition radiation angle on acceleration as an analogue phenomena in special theory of relativity. The last application of our method is the Thomas precession by uniform acceleration with the possible role in the modern physics and cosmology. The comparison of derived results with other relativistic methods is necessary.

  19. Superconducting Radiofrequency (SRF) Acceleration Technology

    Data.gov (United States)

    Federal Laboratory Consortium — SRF cavities enable accelerators to increase particle beam energy levels while minimizing the use of electrical power by all but eliminating electrical resistance....

  20. SHORT ACCELERATION TIMES FROM SUPERDIFFUSIVE SHOCK ACCELERATION IN THE HELIOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Perri, S.; Zimbardo, G., E-mail: silvia.perri@fis.unical.it [Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, I-87036 Rende (Italy)

    2015-12-10

    The analysis of time profiles of particles accelerated at interplanetary shocks allows particle transport properties to be inferred. The frequently observed power-law decay upstream, indeed, implies a superdiffusive particle transport when the level of magnetic field variance does not change as the time interval from the shock front increases. In this context, a superdiffusive shock acceleration (SSA) theory has been developed, allowing us to make predictions of the acceleration times. In this work we estimate for a number of interplanetary shocks, including the solar wind termination shock, the acceleration times for energetic protons in the framework of SSA and we compare the results with the acceleration times predicted by standard diffusive shock acceleration. The acceleration times due to SSA are found to be much shorter than in the classical model, and also shorter than the interplanetary shock lifetimes. This decrease of the acceleration times is due to the scale-free nature of the particle displacements in the framework of superdiffusion. Indeed, very long displacements are possible, increasing the probability for particles far from the front of the shock to return, and short displacements have a high probability of occurrence, increasing the chances for particles close to the front to cross the shock many times.

  1. Nonlinear Particle Acceleration and Thermal Particles in GRB Afterglows

    Science.gov (United States)

    Warren, Donald C.; Ellison, Donald C.; Barkov, Maxim V.; Nagataki, Shigehiro

    2017-02-01

    The standard model for GRB afterglow emission treats the accelerated electron population as a simple power law, N(E)\\propto {E}-p for p≳ 2. However, in standard Fermi shock acceleration, a substantial fraction of the swept-up particles do not enter the acceleration process at all. Additionally, if acceleration is efficient, then the nonlinear back-reaction of accelerated particles on the shock structure modifies the shape of the nonthermal tail of the particle spectra. Both of these modifications to the standard synchrotron afterglow impact the luminosity, spectra, and temporal variation of the afterglow. To examine the effects of including thermal particles and nonlinear particle acceleration on afterglow emission, we follow a hydrodynamical model for an afterglow jet and simulate acceleration at numerous points during the evolution. When thermal particles are included, we find that the electron population is at no time well fitted by a single power law, though the highest-energy electrons are; if the acceleration is efficient, then the power-law region is even smaller. Our model predicts hard–soft–hard spectral evolution at X-ray energies, as well as an uncoupled X-ray and optical light curve. Additionally, we show that including emission from thermal particles has drastic effects (increases by factors of 100 and 30, respectively) on the observed flux at optical and GeV energies. This enhancement of GeV emission makes afterglow detections by future γ-ray observatories, such as CTA, very likely.

  2. Concentrated Light for Accelerated Photo Degradation of Polymer Materials

    DEFF Research Database (Denmark)

    Madsen, Morten Vesterager; Tromholt, Thomas; Norrman, Kion;

    2013-01-01

    Concentrated light is used to perform photochemical degradation of polymer solar cell materials with acceleration factors up to 1200. At constant temperature the photon efficiency in regards to photo degradation is constant for 1–150 suns and oxygen diffusion rates are not a limiting factor. Acce...

  3. Thomas Edison Accelerated Elementary School.

    Science.gov (United States)

    Levin, Henry M.; Chasin, Gene

    This paper describes early outcomes of a Sacramento, California, elementary school that participated in the Accelerated Schools Project. The school, which serves many minority and poor students, began training for the project in 1992. Accelerated Schools were designed to advance the learning rate of students through a gifted and talented approach,…

  4. COMPASS Accelerator Design Technical Overview

    Energy Technology Data Exchange (ETDEWEB)

    Nanni, Emilio; Dolgashev, Valery; Tantawi, Sami; Neilson, Jeff; /SLAC

    2016-03-14

    This report is a survey of technical options for generating a MeV-class accelerator for space based science applications. The survey was performed focusing on the primary technical requirements of the accelerator in the context of a satellite environment with its unique challenges of limited electrical power (PE), thermal isolation, dimensions, payload requirement and electrical isolation.

  5. The influence of epidermal growth factor receptor and tumor differentiation on the response to accelerated radiotherapy of squamous cell carcinomas of the head and neck in the randomized DAHANCA 6 and 7 study

    DEFF Research Database (Denmark)

    Eriksen, Jesper Grau; Steiniche, Torben; Overgaard, Jens

    2005-01-01

    to the repopulation taking place during radiotherapy. The aim of the current study was to address the influence of EGFr and histopathological differentiation when the overall treatment time of radiotherapy was moderately reduced. PATIENTS AND METHODS: Eight hundred and three patients with representative pretreatment...... tissue samples from the randomized DAHANCA 6 and 7 study of 5 vs. 6 fx/wk of radiotherapy. EGFr was visualized using immunohistochemistry and separated into high and low expression before correlation with clinical data. RESULTS: Tumors with high EGFr (84%) responded better to moderately accelerated...... radiotherapy, than carcinomas with low EGFr, using locoregional control as endpoint and a similar pattern was seen, stratifying by well/moderate vs. poor tumor differentiation. Therefore, a combined parameter was constructed showing a more prominent separation of response: tumors with high EGFr and well/moderate...

  6. Accelerated tests of coil coatings

    Directory of Open Access Journals (Sweden)

    Rosales, B. M.

    2003-12-01

    Full Text Available Accelerated laboratory tests on 12 materials in study in the Subgroup 6 of the PATINA Network (CYTED, are discussed for different exposition periods in salt spray, SO2 and Prohesion chambers. International standards used to evaluate failures caused by the different aggressive agents of these laboratory tests are the same as those applied for outdoor expositions. The results exposed contribute to a better understanding of the mechanisms occurred in the diverse natural environments, being mentioned the main analogies and differences respect to factors affecting natural tests. They also allowed to evidence the advantages and limitations in the application of these tests during several days, as compared to the years required to attain similar failure magnitudes through outdoor tests.

    En este trabajo se discuten los ensayos de laboratorio acelerados, realizados sobre 12 materiales de estudio en el Subgrupo 6 de la Red PATINA (CYTED, a diferentes periodos de exposición en cámaras de niebla salina, SO2 y Prohesion. Se utilizaron las normas internacionales para evaluar los fallos causados por los diferentes agentes agresivos de estos ensayos de laboratorio, las cuales se aplican también para los ensayos de exposición a la intemperie. Los resultados expuestos contribuyen a una mejor comprensión de los mecanismos ocurridos en los diversos ambientes naturales, mencionándose las principales analogías y diferencias respecto de los factores que afectan los ensayos naturales. También permitieron evidenciar las ventajas y limitaciones en la aplicación de estos ensayos durante varios días, en comparación con los años requeridos para alcanzar magnitudes de fallos similares por medio de ensayos a intemperie.

  7. Process in high energy heavy ion acceleration

    Science.gov (United States)

    Dinev, D.

    2009-03-01

    A review of processes that occur in high energy heavy ion acceleration by synchrotrons and colliders and that are essential for the accelerator performance is presented. Interactions of ions with the residual gas molecules/atoms and with stripping foils that deliberately intercept the ion trajectories are described in details. These interactions limit both the beam intensity and the beam quality. The processes of electron loss and capture lie at the root of heavy ion charge exchange injection. The review pays special attention to the ion induced vacuum pressure instability which is one of the main factors limiting the beam intensity. The intrabeam scattering phenomena which restricts the average luminosity of ion colliders is discussed. Some processes in nuclear interactions of ultra-relativistic heavy ions that could be dangerous for the performance of ion colliders are represented in the last chapter.

  8. Ultra-accelerated natural sunlight exposure testing

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.J.; Bingham, C.; Goggin, R.; Lewandowski, A.A.; Netter, J.C.

    2000-06-13

    Process and apparatus are disclosed for providing ultra accelerated natural sunlight exposure testing of samples under controlled weathering without introducing unrealistic failure mechanisms in exposed materials and without breaking reciprocity relationships between flux exposure levels and cumulative dose that includes multiple concurrent levels of temperature and relative humidity at high levels of natural sunlight comprising: (a) concentrating solar flux uniformly; (b) directing the controlled uniform sunlight onto sample materials in a chamber enclosing multiple concurrent levels of temperature and relative humidity to allow the sample materials to be subjected to accelerated irradiance exposure factors for a sufficient period of time in days to provide a corresponding time of about at least a years worth of representative weathering of the sample materials.

  9. Ultra-accelerated natural sunlight exposure testing

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, Gary J. (Pine, CO); Bingham, Carl (Lakewood, CO); Goggin, Rita (Englewood, CO); Lewandowski, Allan A. (Evergreen, CO); Netter, Judy C. (Westminster, CO)

    2000-06-13

    Process and apparatus for providing ultra accelerated natural sunlight exposure testing of samples under controlled weathering without introducing unrealistic failure mechanisms in exposed materials and without breaking reciprocity relationships between flux exposure levels and cumulative dose that includes multiple concurrent levels of temperature and relative humidity at high levels of natural sunlight comprising: a) concentrating solar flux uniformly; b) directing the controlled uniform sunlight onto sample materials in a chamber enclosing multiple concurrent levels of temperature and relative humidity to allow the sample materials to be subjected to accelerated irradiance exposure factors for a sufficient period of time in days to provide a corresponding time of about at least a years worth of representative weathering of the sample materials.

  10. Controlled Microwave Heating Accelerates Rolling Circle Amplification.

    Science.gov (United States)

    Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

    2015-01-01

    Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same.

  11. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  12. LHC Dipoles Accelerate

    CERN Multimedia

    2001-01-01

    Andrezej Siemko (left), Peter Sievers (centre), and Lucio Rossi (right), have the exciting challenge of preparing and testing 2000 magnets for the LHC. The LHC is going to require a lot of powerful magnets by the time it begins operation in 2006. More specifically, it is going to need 130 special magnets, 400 quadrupoles, and a whopping 1250 dipoles! Preparing and testing these magnets for the conditions they will encounter in the LHC is not an easy task. But evaluation of the most recently received magnet, from the German company Noell, is showing that while the monumental task of receiving and testing nearly 2000 magnets is going to be exhausting, the goals are definitely attainable. At the moment and over the next year, pre-series magnets (the magnets that CERN uses to fine tune performance) are arriving slowly (90 in total will arrive), but by 2003 the rate of series magnet arrival will accelerate to 9 per week, that's over 450 in a single year! And working with these magnets when they arrive is tough. ...

  13. The entangled accelerating universe

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Diaz, Pedro F. [Colina de los Chopos, Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain); Estacion Ecologica de Biocosmologia, Pedro de Alvarado, 14, 06411-Medellin (Spain)], E-mail: p.gonzalezdiaz@imaff.cfmac.csic.es; Robles-Perez, Salvador [Colina de los Chopos, Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain); Estacion Ecologica de Biocosmologia, Pedro de Alvarado, 14, 06411-Medellin (Spain)

    2009-08-31

    Using the known result that the nucleation of baby universes in correlated pairs is equivalent to spacetime squeezing, we show in this Letter that there exists a T-duality symmetry between two-dimensional warp drives, which are physically expressible as localized de Sitter little universes, and two-dimensional Tolman-Hawking and Gidding-Strominger baby universes respectively correlated in pairs, so that the creation of warp drives is also equivalent to spacetime squeezing. Perhaps more importantly, it has been also seen that the nucleation of warp drives entails a violation of the Bell's inequalities, and hence the phenomena of quantum entanglement, complementarity and wave function collapse. These results are generalized to the case of any dynamically accelerating universe filled with dark or phantom energy whose creation is also physically equivalent to spacetime squeezing and to the violation of the Bell's inequalities, so that the universe we are living in should be governed by essential sharp quantum theory laws and must be a quantum entangled system.

  14. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

    An exhibition of plastic arts and two evenings of performances by sound and visual artists as part of CERN's 50th anniversary celebrations. Fifty candles for CERN, an international laboratory renowned for fundamental research, is a cause for celebration. Since March this year, Geneva and neighbouring parts of France have been the venues for a wealth of small and large-scale events, which will continue until November. Given CERN's location in the commune of Meyrin, the ForuMeyrin is hosting exhibitions of plastic arts and performances entitled: Accelerated Particles. Several works will be exhibited and performed in two 'salons'. Salon des matières: An exhibition of plastic arts From Tues 12 October to Wed 3 November 2004 Tuesdays to Fridays: 16:00 to 19:00 Saturdays: 14:00 to 18:00 Exhibition open late on performance nights, entrance free Salon des particules: Musical and visual performances Tues 12 and Mon 25 October from 20:00 to 23:00 Preview evening for both events: Tues 12 October from 18:...

  15. EXHIBITION: Accelerated Particles

    CERN Multimedia

    2004-01-01

    http://www.cern.ch/cern50/ An exhibition of plastic arts and two evenings of performances by sound and visual artists as part of CERN's fiftieth anniversary celebrations. The fiftieth anniversary of a world famous organization like CERN, an international laboratory specializing in fundamental research, is a cause for celebration. Since March this year, Geneva and neighbouring parts of France have been the venues for a wealth of small and large-scale events, which will continue until November. Given CERN's location in the commune of Meyrin, the ForuMeyrin is hosting two "salons" consisting of an exhibition of plastic arts and evenings of music and visual arts performances with the collective title of "Accelerated Particles". Several works will be exhibited and performed. Salon des matières: An exhibition of plastic arts Until Wednesday 3 November 2004. Tuesdays to Fridays: 4.00 p.m. to 7.00 p.m. Saturdays: 2.00 p.m. to 6.00 p.m. Doors open late on the evening of the performances. Salon des ...

  16. Accelerated shallow water modeling

    Science.gov (United States)

    Gandham, Rajesh; Medina, David; Warburton, Timothy

    2015-04-01

    ln this talk we will describe our ongoing developments in accelerated numerical methods for modeling tsunamis, and oceanic fluid flows using two dimensional shallow water model and/or three dimensional incompressible Navier Stokes model discretized with high order discontinuous Galerkin methods. High order discontinuous Galerkin methods can be computationally demanding, requiring extensive computational time to simulate real time events on traditional CPU architectures. However, recent advances in computing architectures and hardware aware algorithms make it possible to reduce simulation time and provide accurate predictions in a timely manner. Hence we tailor these algorithms to take advantage of single instruction multiple data (SIMD) architecture that is seen in modern many core compute devices such as GPUs. We will discuss our unified and extensive many-core programming library OCCA that alleviates the need to completely re-design the solvers to keep up with constantly evolving parallel programming models and hardware architectures. We will present performance results for the flow simulations demonstrating performance leveraging multiple different multi-threading APIs on GPU and CPU targets.

  17. Actinides, accelerators and erosion

    Science.gov (United States)

    Tims, S. G.; Fifield, L. K.

    2012-10-01

    Fallout isotopes can be used as artificial tracers of soil erosion and sediment accumulation. The most commonly used isotope to date has been 137Cs. Concentrations of 137Cs are, however, significantly lower in the Southern Hemisphere, and furthermore have now declined to 35% of original values due to radioactive decay. As a consequence the future utility of 137Cs is limited in Australia, with many erosion applications becoming untenable within the next 20 years, and there is a need to replace it with another tracer. Plutonium could fill this role, and has the advantages that there were six times as many atoms of Pu as of 137Cs in fallout, and any loss to decay has been negligible due to the long half-lives of the plutonium isotopes. Uranium-236 is another long-lived fallout isotope with significant potential for exploitation as a tracer of soil and sediment movement. Uranium is expected to be more mobile in soils than plutonium (or caesium), and hence the 236U/Pu ratio will vary with soil depth, and so could provide an independent measure of the amount of soil loss. In this paper we discuss accelerator based ultra-sensitive measurements of plutonium and 236U isotopes and their advantages over 137Cs as tracers of soil erosion and sediment movement.

  18. Actinides, accelerators and erosion

    Directory of Open Access Journals (Sweden)

    Fifield L.K.

    2012-10-01

    Full Text Available Fallout isotopes can be used as artificial tracers of soil erosion and sediment accumulation. The most commonly used isotope to date has been 137Cs. Concentrations of 137Cs are, however, significantly lower in the Southern Hemisphere, and furthermore have now declined to 35% of original values due to radioactive decay. As a consequence the future utility of 137Cs is limited in Australia, with many erosion applications becoming untenable within the next 20 years, and there is a need to replace it with another tracer. Plutonium could fill this role, and has the advantages that there were six times as many atoms of Pu as of 137Cs in fallout, and any loss to decay has been negligible due to the long half-lives of the plutonium isotopes. Uranium-236 is another long-lived fallout isotope with significant potential for exploitation as a tracer of soil and sediment movement. Uranium is expected to be more mobile in soils than plutonium (or caesium, and hence the 236U/Pu ratio will vary with soil depth, and so could provide an independent measure of the amount of soil loss. In this paper we discuss accelerator based ultra-sensitive measurements of plutonium and 236U isotopes and their advantages over 137Cs as tracers of soil erosion and sediment movement.

  19. Energy Innovation Acceleration Program

    Energy Technology Data Exchange (ETDEWEB)

    Wolfson, Johanna [Fraunhofer USA Inc., Center for Sustainable Energy Systems, Boston, MA (United States)

    2015-06-15

    The Energy Innovation Acceleration Program (IAP) – also called U-Launch – has had a significant impact on early stage clean energy companies in the Northeast and on the clean energy economy in the Northeast, not only during program execution (2010-2014), but continuing into the future. Key results include: Leverage ratio of 105:1; $105M in follow-on funding (upon $1M investment by EERE); At least 19 commercial products launched; At least 17 new industry partnerships formed; At least $6.5M in revenue generated; >140 jobs created; 60% of assisted companies received follow-on funding within 1 year of program completion; In addition to the direct measurable program results summarized above, two primary lessons emerged from our work executing Energy IAP:; Validation and demonstration awards have an outsized, ‘tipping-point’ effect for startups looking to secure investments and strategic partnerships. An ecosystem approach is valuable, but an approach that evaluates the needs of individual companies and then draws from diverse ecosystem resources to fill them, is most valuable of all.

  20. EXOTIC MAGNETS FOR ACCELERATORS.

    Energy Technology Data Exchange (ETDEWEB)

    WANDERER, P.

    2005-09-18

    Over the last few years, several novel magnet designs have been introduced to meet the requirements of new, high performance accelerators and beam lines. For example, the FAIR project at GSI requires superconducting magnets ramped at high rates ({approx} 4 T/s) in order to achieve the design intensity. Magnets for the RIA and FAIR projects and for the next generation of LHC interaction regions will need to withstand high doses of radiation. Helical magnets are required to maintain and control the polarization of high energy protons at RHIC. In other cases, novel magnets have been designed in response to limited budgets and space. For example, it is planned to use combined function superconducting magnets for the 50 GeV proton transport line at J-PARC to satisfy both budget and performance requirements. Novel coil winding methods have been developed for short, large aperture magnets such as those used in the insertion region upgrade at BEPC. This paper will highlight the novel features of these exotic magnets.

  1. Particle Acceleration in Astrophysical Sources

    CERN Document Server

    Amato, Elena

    2015-01-01

    Astrophysical sources are extremely efficient accelerators. Some sources emit photons up to multi-TeV energies, a signature of the presence, within them, of particles with energies much higher than those achievable with the largest accelerators on Earth. Even more compelling evidence comes from the study of Cosmic Rays, charged relativistic particles that reach the Earth with incredibly high energies: at the highest energy end of their spectrum, these subatomic particles are carrying a macroscopic energy, up to a few Joules. Here I will address the best candidate sources and mechanisms as cosmic particle accelerators. I will mainly focus on Galactic sources such as Supernova Remnants and Pulsar Wind Nebulae, which being close and bright, are the best studied among astrophysical accelerators. These sources are held responsible for most of the energy that is put in relativistic particles in the Universe, but they are not thought to accelerate particles up to the highest individual energies, $\\approx 10^{20}$ eV...

  2. Shear Acceleration in Expanding Flows

    CERN Document Server

    Rieger, F M

    2016-01-01

    Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate the acceleration of energetic charged particles to higher energies. To this end, the gradual shear acceleration coefficient is derived based on an analytical treatment. The results are applied to the context of the relativistic jets of active galactic nuclei. The inferred acceleration timescale is investigated for a variety of conical flow profiles (i.e., power law, Gaussian, Fermi-Dirac) and compared to the relevant radiative and non-radiative loss timescales. The results exemplify that relativistic shear flows are capable of boosting cosmic-rays to extreme energies. Efficient electron acceleration, on the other hand, requires weak magnetic fields and may thus be accompanied by a delayed onset of particle energization and affect the overall jet appearance (e.g., core, ridge ...

  3. The ISAC post-accelerator

    Science.gov (United States)

    Laxdal, R. E.; Marchetto, M.

    2014-01-01

    The acceleration chain of the ISAC facility boosts the energy of both radioactive and stable light and heavy ions for beam delivery to both a medium energy area in ISAC-I and a high energy area in ISAC-II. The post-accelerator comprises a 35.4 MHz RFQ to accelerate beams of A/q ≤ 30 from 2 keV/u to 150 keV/u and a post stripper, 106.1 MHz variable energy drift tube linac (DTL) to accelerate ions of A/q ≤ 6 to a final energy between 0.15 MeV/u to 1.5 MeV/u. A 40 MV superconducting linac further accelerates beam from 1.5 MeV/u to energies above the Coulomb barrier. All linacs operate cw to preserve beam intensity.

  4. Industrial accelerators and their applications

    CERN Document Server

    Hamm, Marianne E

    2012-01-01

    This unique new book is a comprehensive review of the many current industrial applications of particle accelerators, written by experts in each of these fields. Readers will gain a broad understanding of the principles of these applications, the extent to which they are employed, and the accelerator technology utilized. The book also serves as a thorough introduction to these fields for non-experts and laymen. Due to the increased interest in industrial applications, there is a growing interest among accelerator physicists and many other scientists worldwide in understanding how accelerators are used in various applications. The government agencies that fund scientific research with accelerators are also seeking more information on the many commercial applications that have been or can be developed with the technology developments they are funding. Many industries are also doing more research on how they can improve their products or processes using particle beams.

  5. Beam acceleration through proton radio frequency quadrupole accelerator in BARC

    Science.gov (United States)

    Bhagwat, P. V.; Krishnagopal, S.; Mathew, J. V.; Singh, S. K.; Jain, P.; Rao, S. V. L. S.; Pande, M.; Kumar, R.; Roychowdhury, P.; Kelwani, H.; Rama Rao, B. V.; Gupta, S. K.; Agarwal, A.; Kukreti, B. M.; Singh, P.

    2016-05-01

    A 3 MeV proton Radio Frequency Quadrupole (RFQ) accelerator has been designed at the Bhabha Atomic Research Centre, Mumbai, India, for the Low Energy High Intensity Proton Accelerator (LEHIPA) programme. The 352 MHz RFQ is built in 4 segments and in the first phase two segments of the LEHIPA RFQ were commissioned, accelerating a 50 keV, 1 mA pulsed proton beam from the ion source, to an energy of 1.24 MeV. The successful operation of the RFQ gave confidence in the physics understanding and technology development that have been achieved, and indicate that the road forward can now be traversed rather more quickly.

  6. Statistical analysis of data from accelerated ageing tests of PES UF membranes

    NARCIS (Netherlands)

    Zondervan, Edwin; Zwijnenburg, Arie; Roffel, Brian

    2007-01-01

    In this research, membrane life-time was evaluated by means of accelerated ageing experiments. A pressure pulse unit was used to perform the ageing experiments in an accelerated way. An experimental design has been set up and four ageing factors were varied at two levels. The four ageing factors stu

  7. Accelerated cleanup risk reduction

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, R.B.; Aines, R.M.; Blake, R.G.; Copeland, A.B.; Newmark, R.L.; Tompson, A.F.B.

    1998-02-01

    There is no proven technology for remediating contaminant plume source regions in a heterogeneous subsurface. This project is an interdisciplinary effort to develop the requisite new technologies so that will be rapidly accepted by the remediation community. Our technology focus is hydrous pyrolysis/oxidation (HPO) which is a novel in situ thermal technique. We have expanded this core technology to leverage the action of steam injection and place an in situ microbial filter downstream to intercept and destroy the accelerated movement of contaminated groundwater. Most contaminant plume source regions, including the chlorinated solvent plume at LLNL, are in subsurface media characterized by a wide range in hydraulic conductivity. At LLNL, the main conduits for contaminant transport are buried stream channels composed of gravels and sands; these have a hydraulic conductivity in the range of 10{sup -1} to 10{sup -2} cm/s. Clay and silt units with a hydraulic conductivity of 10{sup -1} to 10{sup -6} cm/s bound these buried channels; these are barriers to groundwater movement and contain the highest contaminant concentrations in the source region. New remediation technologies are required because the current ones preferentially access the high conductivity units. HPO is an innovative process for the in situ destruction of contaminants in the entire subsurface. It operates by the injection of steam. We have demonstrated in laboratory experiments that many contaminants rapidly oxidize to harmless compounds at temperatures easily achieved by injecting steam, provided sufficient dissolved oxygen is present. One important challenge in a heterogeneous source region is getting heat, contaminants, and an oxidizing agent in the same place at the same time. We have used the NUFT computer program to simulate the cyclic injection of steam into a contaminated aquifer for design of a field demonstration. We used an 8 hour, steam/oxygen injection cycle followed by a 56 hour relaxation

  8. Accelerated coffee pulp composting.

    Science.gov (United States)

    Sánchez, G; Olguín, E J; Mercado, G

    1999-02-01

    The effect of two abundant, easily available and very low-cost agro-industrial organic residues, i.e., filter cake from the sugar industry and poultry litter, on the composting stabilization time of coffee pulp and on the quality of the produced compost, was evaluated. Piles of one cubic meter were built and monitored within the facilities of a coffee processing plant in the Coatepec region of the State of Veracruz, Mexico. Manual aeration was carried out once a week. A longer thermophilic period (28 days) and a much lower C/N ratio (in the range of 6.9-9.1) were observed in the piles containing the amendments, as compared to the control pile containing only coffee pulp (14 days and a C/N ratio of 14.4, respectively). The maximum assimilation rate of the reducing sugars was 1.6 g kg-1 d-1 (from 7.5 to 5.3%) during the first two weeks when accelerators were present in the proportion of 20% filter cake plus 20% poultry litter, while they accumulated at a rate of 1.2 g kg-1 d-1 (from 7.4 to 9.13%) during the same period in the control pile. The best combination of amendments was 30% filter cake with 20% poultry litter, resulting in a final nitrogen content as high as 4.81%. The second best combination was 20% filter cake with 10% poultry litter, resulting in a compost which also contained a high level of total nitrogen (4.54%). It was concluded that the use of these two residues enhanced the composting process of coffee pulp, promoting a shorter stabilization period and yielding a higher quality of compost.

  9. Operation of the accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, R.C.; Batzka, B.; Billquist, P.J. [and others

    1995-08-01

    Fiscal Year 1994 was the first year of seven-day operation since ATLAS became a national user facility in 1985. ATLAS made the most of the opportunity this year by providing 5200 hours of beam on-target to the research program. A record number of 60 experiments were completed and the {open_quotes}facility reliability{close_quotes} remained near the 90% level. Seven-day operation was made possible with the addition to the staff of two operator positions providing single-operator coverage during the weekend period. The normally scheduled coverage was augmented by an on-call list of system experts who respond to emergencies with phone-in advice and return to the Laboratory when necessary. This staffing approach continues but we rearranged our staffing patterns so that we now have one cryogenics engineer working a shift pattern which includes 8-hour daily coverage during the weekend. ATLAS provided a beam mix to users consisting of 26 different isotopic species, 23% of which were for A>100 in FY 1994. Approximately 60% of the beam time was provided by the Positive Ion Injector, slightly less than the usage rate of FY 1993. Experiments using uranium or lead beams accounted for 16.4% of the total beam time. The ECR ion source and high-voltage platform functioned well throughout the year. A new technique for solid material production in the source was developed which uses a sputtering process wherein the sample of material placed near the plasma chamber wall is biased negatively. Plasma ions are accelerated into the sample and material is sputtered from the surface into the plasma. This technique is now used routinely for many elements. Runs of calcium, germanium, nickel, lead, tellurium, and uranium were carried out with this technique.

  10. "small ACCELERATORS" 24 May - 2 June 2005

    CERN Multimedia

    2005-01-01

    CERN Accelerator School and Kernfysisch Versneller Instituut (KVI) Groningen, the Netherlands announce a course on "Small Accelerators", Hotel Golden Tulip Drenthe, Zeegse, the Netherlands, 24 May - 2 June 2005. This specialised course is dedicated to the physics and the main applications of small accelerators. The course will review the different accelerator types as well as their specificities in terms of accelerator physics.

  11. Proton Acceleration at Oblique Shocks

    Science.gov (United States)

    Galinsky, V. L.; Shevchenko, V. I.

    2011-06-01

    Acceleration at the shock waves propagating oblique to the magnetic field is studied using a recently developed theoretical/numerical model. The model assumes that resonant hydromagnetic wave-particle interaction is the most important physical mechanism relevant to motion and acceleration of particles as well as to excitation and damping of waves. The treatment of plasma and waves is self-consistent and time dependent. The model uses conservation laws and resonance conditions to find where waves will be generated or damped, and hence particles will be pitch-angle-scattered. The total distribution is included in the model and neither introduction of separate population of seed particles nor some ad hoc escape rate of accelerated particles is needed. Results of the study show agreement with diffusive shock acceleration models in the prediction of power spectra for accelerated particles in the upstream region. However, they also reveal the presence of spectral break in the high-energy part of the spectra. The role of the second-order Fermi-like acceleration at the initial stage of the acceleration is discussed. The test case used in the paper is based on ISEE-3 data collected for the shock of 1978 November 12.

  12. Application of electron accelerator worldwide

    Energy Technology Data Exchange (ETDEWEB)

    Machi, Sueo [Japan Atomic Industrial Forum, Inc., Tokyo (Japan)

    2003-02-01

    Electron accelerator is an important radiation source for radiation technology, which covers broad fields such as industry, health care, food and environmental protection. There are about 1,000 electron accelerators for radiation processing worldwide. Electron accelerator has advantage over Co-60 irradiator in term of high dose rate and power, assurance of safety, and higher economic performance at larger volume of irradiation. Accelerator generating higher energy in the range of 10 MeV and high power electron beam is now commercially available. There is a trend to use high-energy electron accelerator replacing Co-60 in case of large through-put of medical products. Irradiated foods, in particular species, are on the commercial market in 35 countries. Electron accelerator is used efficiently and economically for production of new or modified polymeric materials through radiation-induced cross-linking, grafting and polymerization reaction. Another important application of electron beam is the curing of surface coatings in the manufacture of products. Electron accelerators of large capacity are used for cleaning exhaust gases in industrial scale. Economic feasibility studies of this electron beam process have shown that this technology is more cost effective than the conventional process. It should be noted that the conventional limestone process produce gypsum as a by-product, which cannot be used in some countries. By contrast, the by-product of the electron beam process is a valuable fertilizer. (Y. Tanaka)

  13. 2014 CERN Accelerator Schools: Beam Loss and Accelerator Protection

    CERN Multimedia

    2014-01-01

    The US-CERN-JAPAN-RUSSIA Joint International Accelerator School is organising a course on Beam Loss and Accelerator Protection to be held in Newport Beach, California, USA from 5-14 November, 2014.    This school is intended for physicists and engineers who are or may be engaged in the design, construction, and/or operation of accelerators with high power photon or particle beams and/or accelerator sub-systems with large stored energy. Application deadlines are 15 August and 4 September. Further information on this Joint School can be found at: http://cas.web.cern.ch/cas/JAS/Newport%20Beach%202014/NPBadvert.html http://indico.cern.ch/event/287647/ http://uspas.fnal.gov/programs/JAS/JAS14.shtml

  14. Electromagnetic acceleration of permanent magnets

    CERN Document Server

    Dolya, S N

    2015-01-01

    We consider the acceleration of the permanent magnets, consisting of neodymium iron boron by means of the running magnetic field gradient. It is shown that the specific magnetic moment per nucleon in neodymium iron boron is determined by the remained magnetization of the substance. The maximum accessable gradient of the magnetic field accelerating the permanent magnets is determined by the coercive force thirty kilogauss. For the neodymium iron boron magnets this gradient is equal to twenty kilogauss divided by one centimeter. The finite velocity of the magnets six kilometers per second, the length of acceleration is six hundred thirty-seven meters.

  15. Experimental demonstration of 3D accelerating beam arrays.

    Science.gov (United States)

    Yu, Xianghua; Li, Runze; Yan, Shaohui; Yao, Baoli; Gao, Peng; Han, Guoxia; Lei, Ming

    2016-04-10

    Accelerating beams have attracted much attention in the frontiers of optical physics and technology owing to their unique propagation dynamics of nondiffracting, self-healing, and freely accelerating along curved trajectories. Such behaviors essentially arise from the particular phase factor occurring in their spatial frequency spectrum, e.g., the cubic phase associated to the spectrum of Airy beam. In this paper, we theoretically and experimentally demonstrate a sort of accelerating beam arrays, which are composed of spatially separated accelerating beams. By superimposing kinoforms of multifocal patterns into the spatial frequency spectrum of accelerating beams, different types of beam arrays, e.g., Airy beam arrays and two-main-lobe accelerating beam arrays, are generated and measured by scanning a reflection mirror near the focal region along the optical axis. The 3D intensity patterns reconstructed from the experimental data present good agreement with the theoretical counterparts. The combination of accelerating beams with optical beam arrays proposed here may find potential applications in various fields such as optical microscopes, optical micromachining, optical trapping, and so on.

  16. Accelerated GPU based SPECT Monte Carlo simulations.

    Science.gov (United States)

    Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

    2016-06-07

    Monte Carlo (MC) modelling is widely used in the field of single photon emission computed tomography (SPECT) as it is a reliable technique to simulate very high quality scans. This technique provides very accurate modelling of the radiation transport and particle interactions in a heterogeneous medium. Various MC codes exist for nuclear medicine imaging simulations. Recently, new strategies exploiting the computing capabilities of graphical processing units (GPU) have been proposed. This work aims at evaluating the accuracy of such GPU implementation strategies in comparison to standard MC codes in the context of SPECT imaging. GATE was considered the reference MC toolkit and used to evaluate the performance of newly developed GPU Geant4-based Monte Carlo simulation (GGEMS) modules for SPECT imaging. Radioisotopes with different photon energies were used with these various CPU and GPU Geant4-based MC codes in order to assess the best strategy for each configuration. Three different isotopes were considered: (99m) Tc, (111)In and (131)I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational

  17. Accelerated GPU based SPECT Monte Carlo simulations

    Science.gov (United States)

    Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

    2016-06-01

    Monte Carlo (MC) modelling is widely used in the field of single photon emission computed tomography (SPECT) as it is a reliable technique to simulate very high quality scans. This technique provides very accurate modelling of the radiation transport and particle interactions in a heterogeneous medium. Various MC codes exist for nuclear medicine imaging simulations. Recently, new strategies exploiting the computing capabilities of graphical processing units (GPU) have been proposed. This work aims at evaluating the accuracy of such GPU implementation strategies in comparison to standard MC codes in the context of SPECT imaging. GATE was considered the reference MC toolkit and used to evaluate the performance of newly developed GPU Geant4-based Monte Carlo simulation (GGEMS) modules for SPECT imaging. Radioisotopes with different photon energies were used with these various CPU and GPU Geant4-based MC codes in order to assess the best strategy for each configuration. Three different isotopes were considered: 99m Tc, 111In and 131I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational efficiency

  18. Quantitative accelerated degradation testing: Practical approaches

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadian, S. Hossein, E-mail: seyed-h.mohammadian.1@ulaval.c [Centre Interuniversitaire de Recherche sur les Reseaux d' Entreprise, la Logistique et le Transport (CIRRELT), Departement de Genie Mecanique, Pavillon Adrien-Pouliot, Universite Laval, Quebec, G1V 0A6 (Canada) and Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada); Ait-Kadi, Daoud, E-mail: Daoud.Aitkadi@gmc.ulaval.c [Centre Interuniversitaire de Recherche sur les Reseaux d' Entreprise, la Logistique et le Transport (CIRRELT), Departement de Genie Mecanique, Pavillon Adrien-Pouliot, Universite Laval, Quebec, G1V 0A6 (Canada); Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada); Routhier, Francois, E-mail: Francois.Routhier@rea.ulaval.c [Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada)

    2010-02-15

    The concept of accelerated testing by tracking degradation of samples over test time needs to be developed for reliability estimation. This paper aims at proposing practical approaches to conduct accelerated degradation testing on new and available used samples. For this purpose, product failure is related to a suitable physical property. Then, its failure time is defined as the expected time in which its property reaches the critical level. Degradation model of field samples returned from service due to a degrading failure mode has been estimated based on the least square method, and available gap between manufacturer criterion and user's claim (to report a failure) has also been discussed. For a product under some stresses, a general formula has been proposed by the superposition principle in order to estimate its degradation for independent and dependent failure modes. If used samples are available, and acceleration factor of the related test is unknown, partial aging method has been presented to considerably shorten the test time.

  19. SNEAP 80: symposium of Northeastern Accelerator personnel

    Energy Technology Data Exchange (ETDEWEB)

    Billen, J.H. (ed.)

    1980-01-01

    Reports of operations are presented for twenty-seven facilities, along with reports on accelerators in progress, ion sources, insulating gases, charging systems, stripping foils, accelerating tubes, and upgraded accelerator systems. (GHT)

  20. Terahertz-driven linear electron acceleration

    CERN Document Server

    Nanni, Emilio Alessandro; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Miller, R J Dwayne; Kärtner, Franz X

    2014-01-01

    The cost, size and availability of electron accelerators is dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency (RF) accelerating structures operate with 30-50 MeV/m gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional RF structures. However, laser-driven electron accelerators require intense sources and suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here, we demonstrate the first linear acceleration of electrons with keV energy gain using optically-generated terahertz (THz) pulses. THz-driven accelerating structures enable high-gradient electron accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. Increasing the operational frequency of accelerators into the THz band allows for greatly increased accelerating ...

  1. Particle accelerator; the Universe machine

    CERN Multimedia

    Yurkewicz, Katie

    2008-01-01

    "In summer 2008, scientists will switch on one of the largest machines in the world to search for the smallest of particle. CERN's Large Hadron Collider particle accelerator has the potential to chagne our understanding of the Universe."

  2. IGBT accelerated aging data set.

    Data.gov (United States)

    National Aeronautics and Space Administration — Preliminary data from thermal overstress accelerated aging using the aging and characterization system. The data set contains aging data from 6 devices, one device...

  3. Accelerator structure work for NLC

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.H.; Adolphsen, C.; Bane, K.L.F.; Deruyter, H.; Farkas, Z.D.; Hoag, H.A.; Holtkamp, N.; Lavine, T.; Loew, G.A.; Nelson, E.M.; Palmer, R.B.; Paterson, J.M.; Ruth, R.D.; Thompson, K.A.; Vlieks, A.; Wang, J.W.; Wilson, P.B. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Gluckstern, R. [Maryland Univ., College Park, MD (United States); Ko, K.; Kroll, N. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)]|[California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics

    1992-07-01

    The NLC design achieves high luminosity with multiple bunches in each RF pulse. Acceleration of a train of bunches without emittance growth requires control of long range dipole wakefields. SLAC is pursuing a structure design which suppresses the effect of wakefields by varying the physical dimensions of successive cells of the disk-loaded traveling wave structure in a manner which spreads the frequencies of the higher mode while retaining the synchronism between the electrons and the accelerating mode. The wakefields of structures incorporating higher mode detuning have been measured at the Accelerator Test Facility at Argonne. Mechanical design and brazing techniques which avoid getting brazing alloy into the interior of the accelerator are being studied. A test facility for high-power testing of these structures is complete and high power testing has begun.

  4. Advanced Superconducting Test Accelerator (ASTA)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Superconducting Test Accelerator (ASTA) facility will be based on upgrades to the existing NML pulsed SRF facility. ASTA is envisioned to contain 3 to...

  5. Advanced Superconducting Test Accelerator (ASTA)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Superconducting Test Accelerator (ASTA) facility will be based on upgrades to the existing NML pulsed SRF facility. ASTA is envisioned to contain 3 to 6...

  6. Particle acceleration around SNR shocks

    Energy Technology Data Exchange (ETDEWEB)

    Morlino, G., E-mail: morlino@arcetri.astro.it [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5, 50125 Firenze (Italy)

    2013-08-21

    We review the basic features of particle acceleration theory around collisionless shocks in supernova remnants (SNRs). We show how non-linear effects induced by the back reaction of accelerated particles onto the shock dynamics are of paramount importance to support the hipotesys that SNRs are the factories of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of magnetic field amplification and the presence of neutrals in the circumstellar environment. Special attention will be devoted to observational consequences of non-linear effects on the multi-wavelength spectrum of SNRs, with emphasis on X-ray and gamma-ray emission. Finally we also discuss how Balmer lines, detected from several young SNRs, can be used to estimate the shock dynamical properties and the efficiency of CR acceleration.

  7. Particle acceleration around SNR shocks

    CERN Document Server

    Morlino, Giovanni

    2012-01-01

    We review the basic features of particle acceleration theory around collisionless shocks in supernova remnants (SNRs). We show how non linear effects induced by the back reaction of accelerated particles onto the shock dynamics are of paramount importance to support the hipotesys that SNRs are the factories of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of magnetic field amplification and the presence of neutrals in the circumstellar environment. Special attention will be devoted to observational consequences of non linear effects on the multi-wavelength spectrum of SNRs, with emphasis on X-ray and gamma-ray emission. Finally we also discuss how Balmer lines, detected from several young SNRs, can be used to estimate the shock dynamical properties and the efficiency of CR acceleration.

  8. Accelerating advanced-materials commercialization

    Science.gov (United States)

    Maine, Elicia; Seegopaul, Purnesh

    2016-05-01

    Long commercialization times, high capital costs and sustained uncertainty deter investment in innovation for advanced materials. With appropriate strategies, technology and market uncertainties can be reduced, and the commercialization of advanced materials accelerated.

  9. Accelerated Solutions for Transcendental Stiffness Matrix Eigenproblems

    Directory of Open Access Journals (Sweden)

    F.W. Williams

    1996-01-01

    Full Text Available This article outlines many existing and forthcoming methods that can be used alone, or in various combinations, to accelerate the solutions of the transcendental stiffness matrix eigenproblems that arise when the stiffness matrix is assembled from exact member stiffnesses, which are obtained by solving the member differential equations exactly. Thus distributed member mass and/or the flexural effect of axial loading are incorporated exactly, and the solutions are the natural frequencies for vibration problems or the critical load factors for buckling problems.

  10. The KEK Digital Accelerator and Its Brothers

    Science.gov (United States)

    Takayama, Ken

    Circular induction accelerators developed in the last 10 years are discussed. They are characterized by induction acceleration of a charged beam bunch trapped in the barrier bucket. This property enables acceleration of any ion species from an extremely low energy to relativistic energy in a single accelerator ring. In the future, a racetrack-shaped fixed field induction accelerator (induction microtron) could be realized as a unique accelerator for cluster ions such as C-60 and Si-100.

  11. Technology of superconducting accelerator dipoles

    Energy Technology Data Exchange (ETDEWEB)

    Hassenzahl, W.V.; Meuser, R.B.; Taylor, C.

    1983-06-01

    We discuss accelerator dipoles and their characteristics. Other types of magnets, in particular bubble chamber magnets have been quite successful. Their performance is based on cryogenic stability which is addressed only briefly in this chapter. This type of stability is not available to the accelerator designer because of the large quantities of copper or other stabilizer that would reduce the current density in the windings to an unacceptably low value.

  12. Bucharest heavy ion accelerator facility

    Energy Technology Data Exchange (ETDEWEB)

    Ceausescu, V.; Dobrescu, S.; Duma, M.; Indreas, G.; Ivascu, M.; Papureanu, S.; Pascovici, G.; Semenescu, G.

    1986-02-15

    The heavy ion accelerator facility of the Heavy Ion Physics Department at the Institute of Physics and Nuclear Engineering in Bucharest is described. The Tandem accelerator development and the operation of the first stage of the heavy ion postaccelerating system are discussed. Details are given concerning the resonance cavities, the pulsing system matching the dc beam to the RF cavities and the computer control system.

  13. Sequentially pulsed traveling wave accelerator

    Science.gov (United States)

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  14. BRIEF HISTORY OF FFAG ACCELERATORS.

    Energy Technology Data Exchange (ETDEWEB)

    RUGGIERO, A.

    2006-12-04

    Colleagues of mine have asked me few times why we have today so much interest in Fixed-Field Alternating-Gradient (FFAG) accelerators when these were invented a long time ago, and have always been ignored since then. I try here to give a reply with a short history of FFAG accelerators, at least as I know it. I take also the opportunity to clarify few definitions.

  15. Hamiltonian mechanics of stochastic acceleration.

    Science.gov (United States)

    Burby, J W; Zhmoginov, A I; Qin, H

    2013-11-08

    We show how to find the physical Langevin equation describing the trajectories of particles undergoing collisionless stochastic acceleration. These stochastic differential equations retain not only one-, but two-particle statistics, and inherit the Hamiltonian nature of the underlying microscopic equations. This opens the door to using stochastic variational integrators to perform simulations of stochastic interactions such as Fermi acceleration. We illustrate the theory by applying it to two example problems.

  16. Dark Energy or local acceleration?

    CERN Document Server

    Feoli, Antonio

    2016-01-01

    We find that an observer with a suitable acceleration relative to the frame comoving whit the cosmic fluid, in the context of the FRW decelerating universe, measures the same cosmological redshift as the LambdaCDM model. The estimated value of this acceleration is beta = 1.4x10^-9m/s^2. The problem of a too high peculiar velocity can be solved assuming, for the observer, a sort of helical motion.

  17. Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

    CERN Document Server

    Zharkova, Valentina V; Benz, Arnold O; Browning, Phillippa; Dauphin, Cyril; Emslie, A Gordon; Fletcher, Lyndsay; Kontar, Eduard P; Mann, Gottfried; Onofri, Marco; Petrosian, Vahe; Turkmani, Rim; Vilmer, Nicole; Vlahos, Loukas

    2011-01-01

    We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.

  18. Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration

    Science.gov (United States)

    Jing, C.; Kanareykin, A.; Power, J. G.; Conde, M.; Yusof, Z.; Schoessow, P.; Gai, W.

    2007-04-01

    One approach to future high energy particle accelerators is based on the wakefield principle: a leading high-charge drive bunch is used to excite fields in an accelerating structure or plasma that in turn accelerates a trailing low-charge witness bunch. The transformer ratio R is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss of the drive bunch. In general, Rtransformer ratio limitation. We report here the first experimental study of the ramped bunch train (RBT) technique in a dielectric based accelerating structure. A single drive bunch was replaced by two bunches with charge ratio of 1∶2.5 and a separation of 10.5 wavelengths of the fundamental mode. An average measured transformer ratio enhancement by a factor of 1.31 over the single drive bunch case was obtained.

  19. Vacuum Brazing of Accelerator Components

    Science.gov (United States)

    Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

    2012-11-01

    Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

  20. Ponderomotive Acceleration by Relativistic Waves

    CERN Document Server

    Lau, Calvin; Yeh, Po-Chun; Luk, Onnie; McClenaghan, Joseph; Ebisuzaki, Toshikazu; Tajima, Toshiki

    2014-01-01

    In the extreme high intensity regime of electromagnetic (EM) waves in plasma, the acceleration process is found to be dominated by the ponderomotive acceleration (PA). While the wakefields driven by the ponderomotive force of the relativistic intensity EM waves are important, they may be overtaken by the PA itself in the extreme high intensity regime when the dimensionless vector potential $a_0$ of the EM waves far exceeds unity. The energy gain by this regime (in 1D) is shown to be (approximately) proportional to $a_0^2$. Before reaching this extreme regime, the coexistence of the PA and the wakefield acceleration (WA) is observed where the wave structures driven by the wakefields show the phenomenon of multiple and folded wave-breakings. Investigated are various signatures of the acceleration processes such as the dependence on the mass ratio for the energy gain as well as the energy spectral features. The relevance to high energy cosmic ray acceleration and to the relativistic laser acceleration is conside...

  1. High-Intensity Proton Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Jay L. Hirshfield

    2011-12-27

    Analysis is presented for an eight-cavity proton cyclotron accelerator that could have advantages as compared with other accelerators because of its potentially high acceleration gradient. The high gradient is possible since protons orbit in a sequence of TE111 rotating mode cavities of equally diminishing frequencies with path lengths during acceleration that greatly exceed the cavity lengths. As the cavities operate at sequential harmonics of a basic repetition frequency, phase synchronism can be maintained over a relatively wide injection phase window without undue beam emittance growth. It is shown that use of radial vanes can allow cavity designs with significantly smaller radii, as compared with simple cylindrical cavities. Preliminary beam transport studies show that acceptable extraction and focusing of a proton beam after cyclic motion in this accelerator should be possible. Progress is also reported on design and tests of a four-cavity electron counterpart accelerator for experiments to study effects on beam quality arising from variations injection phase window width. This device is powered by four 500-MW pulsed amplifiers at 1500, 1800, 2100, and 2400 MHz that provide phase synchronous outputs, since they are driven from a with harmonics derived from a phase-locked 300 MHz source.

  2. Accelerator and electrodynamics capability review

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Kevin W [Los Alamos National Laboratory

    2010-01-01

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  3. CAS Accelerator Physics (RF for Accelerators) in Denmark

    CERN Multimedia

    Barbara Strasser

    2010-01-01

    The CERN Accelerator School (CAS) and Aarhus University jointly organised a specialised course on RF for Accelerators, at the Ebeltoft Strand Hotel, Denmark from 8 to 17 June 2010.   Caption The challenging programme focused on the introduction of the underlying theory, the study and the performance of the different components involved in RF systems, the RF gymnastics and RF measurements and diagnostics. This academic part was supplemented with three afternoons dedicated to practical hands-on exercises. The school was very successful, with 100 participants representing 25 nationalities. Feedback from the participants was extremely positive, praising the expertise and enthusiasm of the lecturers, as well as the high standard and excellent quality of their lectures. In addition to the academic programme, the participants were able to visit a small industrial exhibition organised by Aarhus University and take part in a one-day excursion consisting of a visit of the accelerators operated ...

  4. Acceleration schedules for a recirculating heavy-ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, W.M.; Grote, D.P.

    2002-05-01

    Recent advances in solid-state switches have made it feasible to design programmable, high-repetition-rate pulsers for induction accelerators. These switches could lower the cost of recirculating induction accelerators, such as the ''small recirculator'' at Lawrence Livermore National Laboratory (LLNL), by substantially reducing the number of induction modules. Numerical work is reported here to determine what effects the use of fewer pulsers at higher voltage would have on the beam quality of the LLNL small recirculator. Lattices with different numbers of pulsers are examined using the fluid/envelope code CIRCE, and several schedules for acceleration and compression are compared for each configuration. For selected schedules, the phase-space dynamics is also studied using the particle-in-cell code WARP3d.

  5. Acceleration of injected electrons by the plasma beat wave accelerator

    Science.gov (United States)

    Joshi, C.; Clayton, C. E.; Marsh, K. A.; Dyson, A.; Everett, M.; Lal, A.; Leemans, W. P.; Williams, R.; Katsouleas, T.; Mori, W. B.

    1992-07-01

    In this paper we describe the recent work at UCLA on the acceleration of externally injected electrons by a relativistic plasma wave. A two frequency laser was used to excite a plasma wave over a narrow range of static gas pressures close to resonance. Electrons with energies up to our detection limit of 9.1 MeV were observed when 2.1 MeV electrons were injected in the plasma wave. No accelerated electrons above the detection threshold were observed when the laser was operated on a single frequency or when no electrons were injected. Experimental results are compared with theoretical predictions, and future prospects for the plasma beat wave accelerator are discussed.

  6. The Accelerator Markup Language and the Universal Accelerator Parser

    Energy Technology Data Exchange (ETDEWEB)

    Sagan, D.; Forster, M.; /Cornell U., LNS; Bates, D.A.; /LBL, Berkeley; Wolski, A.; /Liverpool U. /Cockcroft Inst. Accel. Sci. Tech.; Schmidt, F.; /CERN; Walker, N.J.; /DESY; Larrieu, T.; Roblin, Y.; /Jefferson Lab; Pelaia, T.; /Oak Ridge; Tenenbaum, P.; Woodley, M.; /SLAC; Reiche, S.; /UCLA

    2006-10-06

    A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally, this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.

  7. Acceleration of cutaneous wound healing by brassinosteroids.

    Science.gov (United States)

    Esposito, Debora; Rathinasabapathy, Thirumurugan; Schmidt, Barbara; Shakarjian, Michael P; Komarnytsky, Slavko; Raskin, Ilya

    2013-01-01

    Brassinosteroids are plant growth hormones involved in cell growth, division, and differentiation. Their effects in animals are largely unknown, although recent studies showed that the anabolic properties of brassinosteroids are possibly mediated through the phosphoinositide 3-kinase/protein kinase B signaling pathway. Here, we examined biological activity of homobrassinolide (HB) and its synthetic analogues in in vitro proliferation and migration assays in murine fibroblast and primary keratinocyte cell culture. HB stimulated fibroblast proliferation and migration and weakly induced keratinocyte proliferation in vitro. The effects of topical HB administration on progression of wound closure were further tested in the mouse model of cutaneous wound healing. C57BL/6J mice were given a full-thickness dermal wound, and the rate of wound closure was assessed daily for 10 days, with adenosine receptor agonist CGS-21680 as a positive control. Topical application of brassinosteroid significantly reduced wound size and accelerated wound healing in treated animals. mRNA levels of transforming growth factor beta and intercellular adhesion molecule 1 were significantly lower, while tumor necrosis factor alpha was nearly suppressed in the wounds from treated mice. Our data suggest that topical application of brassinosteroids accelerates wound healing by positively modulating inflammatory and reepithelialization phases of the wound repair process, in part by enhancing Akt signaling in the skin at the edges of the wound and enhancing migration of fibroblasts in the wounded area. Targeting this signaling pathway with brassinosteroids may represent a promising approach to the therapy of delayed wound healing.

  8. Derivation of Hamiltonians for accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Symon, K.R.

    1997-09-12

    In this report various forms of the Hamiltonian for particle motion in an accelerator will be derived. Except where noted, the treatment will apply generally to linear and circular accelerators, storage rings, and beamlines. The generic term accelerator will be used to refer to any of these devices. The author will use the usual accelerator coordinate system, which will be introduced first, along with a list of handy formulas. He then starts from the general Hamiltonian for a particle in an electromagnetic field, using the accelerator coordinate system, with time t as independent variable. He switches to a form more convenient for most purposes using the distance s along the reference orbit as independent variable. In section 2, formulas will be derived for the vector potentials that describe the various lattice components. In sections 3, 4, and 5, special forms of the Hamiltonian will be derived for transverse horizontal and vertical motion, for longitudinal motion, and for synchrobetatron coupling of horizontal and longitudinal motions. Hamiltonians will be expanded to fourth order in the variables.

  9. Industrial Electron Accelerators Type ILU

    CERN Document Server

    Auslender, Vadim; Cheskidov, Vladimir; Faktorovich, Boris; Gorbunov, Vladimir; Gornakov, Igor; Nekhaev, V E; Panfilov, Alexander; Sidorov, Alexander; Tkachenko, Vadim; Tuvik, Alfred; Voronin, Leonid

    2005-01-01

    The report describes the electron accelerators of ILU series covering the energy range from 0.5 to 5 MeV with beam power up to 50 kW. The pulse linear accelerators type ILU are developed since 1970 in Budker institute of Nuclear Physics and are supplied to the industry. The ILU machines are purposed for wide application in various technological processes and designed for long continuous and round-the-clock work in industrial conditions. A principle of acceleration of electrons in the gap of HF resonator is used in the ILU machines. The HF resonator has toroidal form. The electron gun is placed in one of the protruding electrodes forming the accelerating gap of the resonator. The resonator is fed from HF autogenerator realized on the industrial triode, the feedback signal is given from the resonator. The absence of outer beam injection and usage of self-excited HF generator simplify the design of accelerator and ensure its reliable operation.

  10. Accelerator Technology Division annual report, FY 1989

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    This paper discusses: accelerator physics and special projects; experiments and injectors; magnetic optics and beam diagnostics; accelerator design and engineering; radio-frequency technology; accelerator theory and simulation; free-electron laser technology; accelerator controls and automation; and high power microwave sources and effects.

  11. 38 CFR 9.14 - Accelerated Benefits.

    Science.gov (United States)

    2010-07-01

    ...' GROUP LIFE INSURANCE AND VETERANS' GROUP LIFE INSURANCE § 9.14 Accelerated Benefits. (a) What is an Accelerated Benefit? An Accelerated Benefit is a payment of a portion of your Servicemembers' Group Life...? ____ Yes__ No__ The patient applied for an accelerated benefit under his/her government life...

  12. Linear accelerator for radioisotope production

    Energy Technology Data Exchange (ETDEWEB)

    Hansborough, L.D.; Hamm, R.W.; Stovall, J.E.

    1982-02-01

    A 200- to 500-..mu..A source of 70- to 90-MeV protons would be a valuable asset to the nuclear medicine program. A linear accelerator (linac) can achieve this performance, and it can be extended to even higher energies and currents. Variable energy and current options are available. A 70-MeV linac is described, based on recent innovations in linear accelerator technology; it would be 27.3 m long and cost approx. $6 million. By operating the radio-frequency (rf) power system at a level necessary to produce a 500-..mu..A beam current, the cost of power deposited in the radioisotope-production target is comparable with existing cyclotrons. If the rf-power system is operated at full power, the same accelerator is capable of producing an 1140-..mu..A beam, and the cost per beam watt on the target is less than half that of comparable cyclotrons.

  13. Virtual gap dielectric wall accelerator

    Science.gov (United States)

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  14. Symposium on accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-01-01

    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

  15. A Multibunch Plasma Wakefield Accelerator

    CERN Document Server

    Kallos, Efthymios; Ben-Zvi, Ilan; Katsouleas, Thomas C; Kimura, Wayne D; Kusche, Karl; Muggli, Patric; Pavlishin, Igor; Pogorelsky, Igor; Yakimenko, Vitaly; Zhou, Feng

    2005-01-01

    We investigate a plasma wakefield acceleration scheme where a train of electron microbunches feeds into a high density plasma. When the microbunch train enters such a plasma that has a corresponding plasma wavelength equal to the microbunch separation distance, a strong wakefield is expected to be resonantly driven to an amplitude that is at least one order of magnitude higher than that using an unbunched beam. PIC simulations have been performed using the beamline parameters of the Brookhaven National Laboratory Accelerator Test Facility operating in the configuration of the STELLA inverse free electron laser (IFEL) experiment. A 65 MeV electron beam is modulated by a 10.6 um CO2 laser beam via an IFEL interaction. This produces a train of ~90 microbunches separated by the laser wavelength. In this paper, we present both a simple theoretical treatment and simulation results that demonstrate promising results for the multibunch technique as a plasma-based accelerator.

  16. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  17. Superconducting Magnets for Particle Accelerators

    CERN Document Server

    Rossi, L

    2012-01-01

    Superconductivity has been the most influential technology in the field of accelerators in the last 30 years. Since the commissioning of the Tevatron, which demonstrated the use and operability of superconductivity on a large scale, superconducting magnets and rf cavities have been at the heart of all new large accelerators. Superconducting magnets have been the invariable choice for large colliders, as well as cyclotrons and large synchrotrons. In spite of the long history of success, superconductivity remains a difficult technology, requires adequate R&D and suitable preparation, and has a relatively high cost. Hence, it is not surprising that the development has also been marked by a few setbacks. This article is a review of the main superconducting accelerator magnet projects; it highlights the main characteristics and main achievements, and gives a perspective on the development of superconducting magnets for the future generation of very high energy colliders.

  18. Progress Towards Doubling the Beam Power at Fermilab's Accelerator Complex

    Energy Technology Data Exchange (ETDEWEB)

    Kourbanis, Ioanis [Fermilab

    2014-07-01

    After a 16 month shutdown to reconfigure the Fermilab Accelerators for high power operations, the Fermilab Accelerator Complex is again providing beams for numerous Physics Experiments. By using the Recycler to slip stack protons while the Main Injector is ramping, the beam power at 120 GeV can reach 700 KW, a factor of 2 increase. The progress towards doubling the Fermilab's Accelerator complex beam power will be presented.

  19. Accelerating Vaccine Formulation Development Using Design of Experiment Stability Studies.

    Science.gov (United States)

    Ahl, Patrick L; Mensch, Christopher; Hu, Binghua; Pixley, Heidi; Zhang, Lan; Dieter, Lance; Russell, Ryann; Smith, William J; Przysiecki, Craig; Kosinski, Mike; Blue, Jeffrey T

    2016-10-01

    Vaccine drug product thermal stability often depends on formulation input factors and how they interact. Scientific understanding and professional experience typically allows vaccine formulators to accurately predict the thermal stability output based on formulation input factors such as pH, ionic strength, and excipients. Thermal stability predictions, however, are not enough for regulators. Stability claims must be supported by experimental data. The Quality by Design approach of Design of Experiment (DoE) is well suited to describe formulation outputs such as thermal stability in terms of formulation input factors. A DoE approach particularly at elevated temperatures that induce accelerated degradation can provide empirical understanding of how vaccine formulation input factors and interactions affect vaccine stability output performance. This is possible even when clear scientific understanding of particular formulation stability mechanisms are lacking. A DoE approach was used in an accelerated 37(°)C stability study of an aluminum adjuvant Neisseria meningitidis serogroup B vaccine. Formulation stability differences were identified after only 15 days into the study. We believe this study demonstrates the power of combining DoE methodology with accelerated stress stability studies to accelerate and improve vaccine formulation development programs particularly during the preformulation stage.

  20. The Toledo heavy ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Haar, R.R. (Dept. of Physics and Astronomy, Univ. of Toledo, OH (United States)); Beideck, D.J. (Dept. of Physics and Astronomy, Univ. of Toledo, OH (United States)); Curtis, L.J. (Dept. of Physics and Astronomy, Univ. of Toledo, OH (United States)); Kvale, T.J. (Dept. of Physics and Astronomy, Univ. of Toledo, OH (United States)); Sen, A. (Dept. of Physics and Astronomy, Univ. of Toledo, OH (United States)); Schectman, R.M. (Dept. of Physics and Astronomy, Univ. of Toledo, OH (United States)); Stevens, H.W. (Dept. of Physics and Astronomy, Univ. of Toledo, OH (United States))

    1993-06-01

    The recently installed 330 kV electrostatic positive ion accelerator at the University of Toledo is described. Experiments have been performed using ions ranging from H[sup +] to Hg[sup 2+] and exotic molecules such as HeH[sup +]. Most of these experiments involve the beam-foil studies of the lifetimes of excited atomic states and the apparatus used for these experiments is also described. Another beamline is available for ion-implantation. The Toledo heavy ion accelerator facility welcomes outside users. (orig.)

  1. Geometric integration for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Forest, Etienne [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2006-05-12

    This paper is a very personal view of the field of geometric integration in accelerator physics-a field where often work of the highest quality is buried in lost technical notes or even not published; one has only to think of Simon van der Meer Nobel prize work on stochastic cooling-unpublished in any refereed journal. So I reconstructed the relevant history of geometrical integration in accelerator physics as much as I could by talking to collaborators and using my own understanding of the field. The reader should not be too surprised if this account is somewhere between history, science and perhaps even fiction.

  2. Thermodynamics of Accelerating Black Holes.

    Science.gov (United States)

    Appels, Michael; Gregory, Ruth; Kubizňák, David

    2016-09-23

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  3. Electron Cloud Effects in Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.A.

    2012-11-30

    Abstract We present a brief summary of various aspects of the electron-cloud effect (ECE) in accelerators. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire ?ECLOUD? series [1?22]. In addition, the proceedings of the various flavors of Particle Accelerator Conferences [23] contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series [24] contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC [25].

  4. Electron Cloud Effects in Accelerators

    CERN Document Server

    Furman, M A

    2013-01-01

    We present a brief summary of various aspects of the electron-cloud effect (ECE) in accelerators. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire "ECLOUD" series [122]. In addition, the proceedings of the various flavors of Particle Accelerator Conferences [23] contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series [24] contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC [25].

  5. Calorimetry at industrial electron accelerators

    DEFF Research Database (Denmark)

    Miller, Arne; Kovacs, A.

    1985-01-01

    Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials such as grap......Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials...

  6. OpenMP for Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, J C; Stotzer, E J; Hart, A; de Supinski, B R

    2011-03-15

    OpenMP [13] is the dominant programming model for shared-memory parallelism in C, C++ and Fortran due to its easy-to-use directive-based style, portability and broad support by compiler vendors. Similar characteristics are needed for a programming model for devices such as GPUs and DSPs that are gaining popularity to accelerate compute-intensive application regions. This paper presents extensions to OpenMP that provide that programming model. Our results demonstrate that a high-level programming model can provide accelerated performance comparable to hand-coded implementations in CUDA.

  7. Using the factors that have a positive impact on the retention of low socioeconomic students to prepare accelerated enrolled nurses for the science units of a nursing degree. A Practice Report

    Directory of Open Access Journals (Sweden)

    Sheila Doggrell

    2015-03-01

    Full Text Available At a campus in a low socioeconomic (SES area, our University allows enrolled nurses entry into the second year of a Bachelor of Nursing, but attrition is high.  Using the factors, described by Yorke and Thomas (2003 to have a positive impact on the attrition of low SES students, we developed strategies to prepare the enrolled nurses for the pharmacology and bioscience units of a nursing degree with the aim of reducing their attrition.  As a strategy, the introduction of review lectures of anatomy, physiology and microbiology, was associated with significantly reduced attrition rates. The subsequent introduction of a formative website activity of some basic concepts in bioscience and pharmacology, and a workshop addressing study skills and online resources, were associated with a further reduction in attrition rates of enrolled nursing students in a Bachelor of Nursing

  8. Superconducting linear accelerator system for NSC

    Indian Academy of Sciences (India)

    P N Prakash; T S Datta; B P Ajith Kumar; J Antony; P Barua; J Chacko; A Choudhury; G K Chadhari; S Ghosh; S Kar; S A Krishnan; Manoj Kumar; Rajesh Kumar; A Mandal; D S Mathuria; R S Meena; R Mehta; K K Mistri; A Pandey; M V Suresh Babu; B K Sahu; A Sarkar; S S K Sonti; A Rai; S Venkatramanan; J Zacharias; R K Bhowmik; A Roy

    2002-11-01

    This paper reports the construction of a superconducting linear accelerator as a booster to the 15 UD Pelletron accelerator at Nuclear Science Centre, New Delhi. The LINAC will use superconducting niobium quarter wave resonators as the accelerating element. Construction of the linear accelerator has progressed sufficiently. Details of the entire accelerator system including the cryogenics facility, RF electronics development, facilities for fabricating niobium resonators indigenously, and present status of the project are presented.

  9. Gradient limitations in room temperature and superconducting acceleration structures

    Energy Technology Data Exchange (ETDEWEB)

    Solyak, N.A.; /Fermilab

    2008-10-01

    Accelerating gradient is a key parameter of the accelerating structure in large linac facilities, like future Linear Collider. In room temperature accelerating structures the gradient is limited mostly by breakdown phenomena, caused by high surface electric fields or pulse surface heating. High power processing is a necessary procedure to clean surface and improve the gradient. In the best tested X-band structures the achieved gradient is exceed 100 MV/m in of {approx}200 ns pulses for breakdown rate of {approx} 10{sup -7}. Gradient limit depends on number of factors and no one theory which can explain all sets of experimental results and predict gradient in new accelerating structure. In paper we briefly overview the recent experimental results of breakdown studies, progress in understanding of gradient limitations and scaling laws. Although superconducting rf technology has been adopted throughout the world for ILC, it has frequently been difficult to reach the predicted performance in these structures due to a number of factors: multipactoring, field emission, Q-slope, thermal breakdown. In paper we are discussing all these phenomena and the ways to increase accelerating gradient in SC cavity, which are a part of worldwide R&D program.

  10. Implementation of GPU-accelerated back projection for EPR imaging.

    Science.gov (United States)

    Qiao, Zhiwei; Redler, Gage; Epel, Boris; Qian, Yuhua; Halpern, Howard

    2015-01-01

    Electron paramagnetic resonance (EPR) Imaging (EPRI) is a robust method for measuring in vivo oxygen concentration (pO2). For 3D pulse EPRI, a commonly used reconstruction algorithm is the filtered backprojection (FBP) algorithm, in which the backprojection process is computationally intensive and may be time consuming when implemented on a CPU. A multistage implementation of the backprojection can be used for acceleration, however it is not flexible (requires equal linear angle projection distribution) and may still be time consuming. In this work, single-stage backprojection is implemented on a GPU (Graphics Processing Units) having 1152 cores to accelerate the process. The GPU implementation results in acceleration by over a factor of 200 overall and by over a factor of 3500 if only the computing time is considered. Some important experiences regarding the implementation of GPU-accelerated backprojection for EPRI are summarized. The resulting accelerated image reconstruction is useful for real-time image reconstruction monitoring and other time sensitive applications.

  11. Pulsed-focusing recirculating linacs for muon acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

    2014-12-31

    Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of

  12. PULSED-FOCUSING RECIRCULATING LINACS FOR MUON ACCELERATION

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland PAUL

    2014-12-31

    Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of

  13. Tumor Necrosis Factor-Like Weak Inducer of Apoptosis Accelerates the Progression of Renal Fibrosis in Lupus Nephritis by Activating SMAD and p38 MAPK in TGF-β1 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Zhiqin Liu

    2016-01-01

    Full Text Available This study aim was to explore the effects of tumor necrosis factor-like weak inducer of apoptosis (TWEAK in lupus nephritis and its potential underlying mechanisms. MRL/lpr mice were used for in vivo experiments and human proximal tubular cells (HK2 cells were used for in vitro experiments. Results showed that MRL/lpr mice treated with vehicle solution or LV-Control shRNA displayed significant proteinuria and severe renal histopathological changes. LV-TWEAK-shRNA treatment reversed these changes and decreased renal expressions of TWEAK, TGF-β1, p-p38 MAPK, p-Smad2, COL-1, and α-SMA proteins. In vitro, hTWEAK treatment upregulated the expressions of TGF-β1, p-p38 MAPK, p-SMAD2, α-SMA, and COL-1 proteins in HK2 cells and downregulated the expressions of E-cadherin protein, which were reversed by cotreatment with anti-TWEAK mAb or SB431542 treatment. These findings suggest that TWEAK may contribute to chronic renal changes and renal fibrosis by activating TGF-β1 signaling pathway, and phosphorylation of Smad2 and p38 MAPK proteins was also involved in this signaling pathway.

  14. CERNois wins prestigious accelerator award

    CERN Multimedia

    Katarina Anthony

    2011-01-01

    During the 2nd International Particle Accelerator Conference, CERN’s Rogelio Tomás García became the first Spaniard to receive the Frank Sacherer Prize for his work in particle beam optics.   Rogelio Tomás García at the 2nd International Particle Accelerator Conference. The Frank Sacherer Prize is awarded to physicists who have made a “significant, original contribution to the accelerator field" early on in their career. This year the prize was given to Rogelio Tomás García who, at only 35 years of age, has made important contributions to the optics design, optics measurement, and correction techniques applied at both the LHC and Brookhaven’s RHIC. “Tomás has had a vital impact on CERN’s beam optics studies and has made very impressive achievements in the field of beam optics,” says Oliver Brüning, Head of the Accelerators and Beam Physics...

  15. Thomas Jefferson National Accelerator Facility

    Energy Technology Data Exchange (ETDEWEB)

    Grames, Joseph; Higinbotham, Douglas; Montgomery, Hugh

    2010-09-08

    The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, USA, is one of ten national laboratories under the aegis of the Office of Science of the U.S. Department of Energy (DOE). It is managed and operated by Jefferson Science Associates, LLC. The primary facility at Jefferson Lab is the Continuous Electron Beam Accelerator Facility (CEBAF) as shown in an aerial photograph in Figure 1. Jefferson Lab was created in 1984 as CEBAF and started operations for physics in 1995. The accelerator uses superconducting radio-frequency (srf) techniques to generate high-quality beams of electrons with high-intensity, well-controlled polarization. The technology has enabled ancillary facilities to be created. The CEBAF facility is used by an international user community of more than 1200 physicists for a program of exploration and study of nuclear, hadronic matter, the strong interaction and quantum chromodynamics. Additionally, the exceptional quality of the beams facilitates studies of the fundamental symmetries of nature, which complement those of atomic physics on the one hand and of high-energy particle physics on the other. The facility is in the midst of a project to double the energy of the facility and to enhance and expand its experimental facilities. Studies are also pursued with a Free-Electron Laser produced by an energy-recovering linear accelerator.

  16. Program Evaluation: Accelerating Retained Students

    Science.gov (United States)

    Juneau, Lisa

    2014-01-01

    The purpose of this program evaluation was to evaluate the first year of an acceleration program that allowed students who were retained a grade level for not performing on academic level in early elementary school an opportunity to rejoin their age appropriate class. The primary focus of the evaluation was to evaluate the effectiveness of an…

  17. Cosmological Acceleration from Gravitational Waves

    CERN Document Server

    Marochnik, Leonid

    2015-01-01

    It is shown that the classical gravitational waves of super-horizon wavelengths are able to form the de Sitter accelerated expansion of the empty (with no matter fields) Universe. The contemporary Universe is about 70% empty and asymptotically is going to become completely empty, so the effect caused by emptiness should be already very noticeable. It could manifest itself as the dark energy.

  18. Observations of Collective Ion Acceleration.

    Science.gov (United States)

    1981-01-01

    possible benefit can be listed. In cancer therapy, radiation produced by ion beams may be more selectively directed into tumors. Ion beams in spallation...34Autoresonant Accelerator Concept," Phys. Rev. Lett. 31, 1234 (1973). 50. S. Humphries, J. J. Lee, and R. N. Sudan, "Generation of Incense Pulsed Ion Beams

  19. CLIC Drive Beam Accelerating Structures

    CERN Document Server

    Wegner, Rolf

    2012-01-01

    Travelling structures for accelerating the high-current (4.2 A) CLIC Drive Beam to an energy of 2.37 GeV are presented. The structures are optimised for efficiency (full beam loading operation) and a desired filling time. Higher order modes are studied and are reduced by detuning along the structure and by damping with silicon carbide loads.

  20. Physics Needs for Future Accelerators

    CERN Document Server

    Lykken, J D

    2000-01-01

    Contents: 1. Prologomena to any meta future physics 1.1 Physics needs for building future accelerators 1.2 Physics needs for funding future accelerators 2. Physics questions for future accelerators 2.1 Crimes and misapprehensions 2.1.1 Organized religion 2.1.2 Feudalism 2.1.3 Trotsky was right 2.2 The Standard Model as an effective field theory 2.3 What is the scale of new physics? 2.4 What could be out there? 2.5 Model-independent conclusions 3. Future accelerators 3.1 What is the physics driving the LHC? 3.2 What is the physics driving the LC? 3.2.1 Higgs physics is golden 3.2.2 LHC won't be sufficient to unravel the new physics as the TeV scale 3.2.3 LC precision measurements can pin down new physics scales 3.3 Why a Neutrino Factory? 3.4 Pushing the energy frontier

  1. Post-LHC accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Gourlay, Stephen A.

    2001-06-10

    The design and practicality of future accelerators, such as hadron colliders and neutrino factories being considered to supercede the LHC, will depend greatly on the choice of superconducting magnets. Various possibilities will be reviewed and discussed, taking into account recent progress and projected improvements in magnet design and conductor development along with the recommendations from the 2001 Snowmass workshop.

  2. Repair of overheating linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Barkley, Walter; Baldwin, William; Bennett, Gloria; Bitteker, Leo; Borden, Michael; Casados, Jeff; Fitzgerald, Daniel; Gorman, Fred; Johnson, Kenneth; Kurennoy, Sergey; Martinez, Alberto; O’Hara, James; Perez, Edward; Roller, Brandon; Rybarcyk, Lawrence; Stark, Peter; Stockton, Jerry

    2004-01-01

    Los Alamos Neutron Science Center (LANSCE) is a proton accelerator that produces high energy particle beams for experiments. These beams include neutrons and protons for diverse uses including radiography, isotope production, small feature study, lattice vibrations and material science. The Drift Tube Linear Accelerator (DTL) is the first portion of a half mile long linear section of accelerator that raises the beam energy from 750 keV to 100 MeV. In its 31st year of operation (2003), the DTL experienced serious issues. The first problem was the inability to maintain resonant frequency at full power. The second problem was increased occurrences of over-temperature failure of cooling hoses. These shortcomings led to an investigation during the 2003 yearly preventative maintenance shutdown that showed evidence of excessive heating: discolored interior tank walls and coper oxide deposition in the cooling circuits. Since overheating was suspected to be caused by compromised heat transfer, improving that was the focus of the repair effort. Investigations revealed copper oxide flow inhibition and iron oxide scale build up. Acid cleaning was implemented with careful attention to protection of the base metal, selection of components to clean and minimization of exposure times. The effort has been very successful in bringing the accelerator through a complete eight month run cycle allowing an incredible array of scientific experiments to be completed this year (2003-2004). This paper will describe the systems, investigation analysis, repair, return to production and conclusion.

  3. Technology and applications of advanced accelerator concepts

    CERN Document Server

    Chou, Weiren

    2016-01-01

    Since its invention in the 1920s, particle accelerators have made tremendous progress in accelerator science, technology and applications. However, the fundamental acceleration principle, namely, to apply an external radiofrequency (RF) electric field to accelerate charged particles, remains unchanged. As this method (either room temperature RF or superconducting RF) is approaching its intrinsic limitation in acceleration gradient (measured in MeV/m), it becomes apparent that new methods with much higher acceleration gradient (measured in GeV/m) must be found for future very high energy accelerators as well as future compact (table-top or room-size) accelerators. This volume introduces a number of advanced accelerator concepts (AAC) — their principles, technologies and potential applications. For the time being, none of them stands out as a definitive direction in which to go. But these novel ideas are in hot pursuit and look promising. Furthermore, some AAC requires a high power laser system. This has the ...

  4. Limitations on plasma acceleration due to synchrotron losses

    CERN Document Server

    Barletta, W A; Bonifacio, R; De Salvo, L

    1999-01-01

    In this letter we consider the effect of synchrotron radiation losses due to the betatron motion of the electron beam in its self-induced magnetic field in a plasma accelerator taking into account the charge neutralization factor. The most favorable case is where the plasma density is smaller than the beam density. The contrary regime is strongly disfavored by the synchrotron radiation loss for beams with characteristics for TeV energies. In both cases we find that upon increasing the plasma density the synchrotron losses kill the acceleration process, so that there are limitations on the maximum allowable plasma density.

  5. Experience with magnetic shielding of a large scale accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sergei Nagaitsev et al.

    2001-08-14

    It is not unusual to place multiple accelerators in a common enclosure to save on civil construction costs. This often complicates operations, especially if accelerators are affecting each other. At Fermilab, the influence of a rapidly cycling Main Injector (MI) synchrotron on an antiproton storage ring (Recycler), placed in a common tunnel, was initially found to be unacceptable for a reliable operation of the Recycler. Initial closed orbit excursions in the Recycler ring during the MI ramp were in excess of 5 mm (rms). This paper describes a shielding technique, used to reduce these orbit excursions by a factor of five.

  6. CAS - CERN Accelerator School: Advanced Accelerator Physics Course

    CERN Document Server

    Herr, W

    2014-01-01

    This report presents the proceedings of the Course on Advanced Accelerator Physics organized by the CERN Accelerator School. The course was held in Trondheim, Norway from 18 to 29 August 2013, in collaboration with the Norwegian University of Science and Technology. Its syllabus was based on previous courses and in particular on the course held in Berlin 2003 whose proceedings were published as CERN Yellow Report CERN- 2006-002. The field has seen significant advances in recent years and some topics were presented in a new way and other topics were added. The lectures were supplemented with tutorials on key topics and 14 hours of hands on courses on Optics Design and Corrections, RF Measurement Techniques and Beam Instrumentation and Diagnostics. These courses are a key element of the Advanced Level Course.

  7. GPU accelerated particle visualization with Splotch

    Science.gov (United States)

    Rivi, M.; Gheller, C.; Dykes, T.; Krokos, M.; Dolag, K.

    2014-07-01

    Splotch is a rendering algorithm for exploration and visual discovery in particle-based datasets coming from astronomical observations or numerical simulations. The strengths of the approach are production of high quality imagery and support for very large-scale datasets through an effective mix of the OpenMP and MPI parallel programming paradigms. This article reports our experiences in re-designing Splotch for exploiting emerging HPC architectures nowadays increasingly populated with GPUs. A performance model is introduced to guide our re-factoring of Splotch. A number of parallelization issues are discussed, in particular relating to race conditions and workload balancing, towards achieving optimal performances. Our implementation was accomplished by using the CUDA programming paradigm. Our strategy is founded on novel schemes achieving optimized data organization and classification of particles. We deploy a reference cosmological simulation to present performance results on acceleration gains and scalability. We finally outline our vision for future work developments including possibilities for further optimizations and exploitation of hybrid systems and emerging accelerators.

  8. Predicting edge seal performance from accelerated testing

    Science.gov (United States)

    Hardikar, Kedar; Vitkavage, Dan; Saproo, Ajay; Krajewski, Todd

    2014-10-01

    Degradation in performance of a PV module attributable to moisture ingress has received significant attention in PV reliability research. Assessment of field performance of PV modules against moisture ingress through product-level testing in temperature-humidity control chambers poses challenges. Development of a meaningful acceleration factor model is challenging due to different rates of degradation of components embedded in a PV module, when exposed to moisture. Test results are typically a convolution of moisture barrier performance of the edge seal and degradation of laminated components when exposed to moisture. It is desirable to have an alternate method by which moisture barrier performance of the edge seal in its end product form can be assessed in any given field conditions, independent of particular cell design. In this work, a relatively inexpensive test technique was developed to test the edge seal in its end product form in a manner that is decoupled from other components of the PV module. A theoretical framework was developed to assess moisture barrier performance of edge seal with desiccants subjected to different conditions. This framework enables the analysis of test results from accelerated tests and prediction of the field performance of the edge seal. Results from this study lead to the conclusion that the edge seal on certain Miasole glass-glass modules studied is effective for the most aggressive weather conditions examined, beyond the intended service.

  9. Silymarin Accelerates Liver Regeneration after Partial Hepatectomy

    Directory of Open Access Journals (Sweden)

    Jia-Ping Wu

    2015-01-01

    Full Text Available Partial hepatectomy (PHx is a liver regeneration physiological response induced to maintain homeostasis. Liver regeneration evolved presumably to protect wild animals from catastrophic liver loss caused by toxins or tissue injury. Silymarin (Sm ability to stimulate liver regeneration has been an object of curiosity for many years. Silymarin has been investigated for use as an antioxidant and anticarcinogen. However, its use as a supportive treatment for liver damage is elusive. In this study, we fed silymarin (Sm, 25 mg/kg to male Sprague-Dawley rats for 7 weeks. Surgical 2/3 PHx was then conducted on the rats at 6 hrs, 24 hrs, and 72 hrs. Western blot and RT-PCR were conducted to detect the cell cycle activities and silymarin effects on hepatic regeneration. The results showed that silymarin enhanced liver regeneration by accelerating the cell cycle in PHx liver. Silymarin led to increased G1 phase (cyclin D1/pRb, S phase (cyclin E/E2F, G2 phase (cyclin B, and M phase (cyclin A protein and mRNA at 6 hrs, 24 hrs, and 72 hrs PHx. HGF, TGFα, and TGFβ1 growth factor expressions were also enhanced. We suggest that silymarin plays a crucial role in accelerated liver regeneration after PHx.

  10. The Effect of Novel Binary Accelerator System on Properties of Vulcanized Natural Rubber

    Directory of Open Access Journals (Sweden)

    Moez Kamoun

    2009-01-01

    Full Text Available The mechanical properties, curing characteristics, and swelling behaviour of vulcanized natural rubber with a novel binary accelerator system are investigated. Results indicate that the mechanical properties were improved. Crosslinking density of vulcanized natural rubber was measured by equilibrium swelling method. As a result, the new binary accelerator was found to be able to improve both cure rate and crosslinking density. Using the numerical analysis of test interaction between binary accelerator and operational modelling of vulcanization-factors experiments, it can be concluded that the interaction (Cystine, N-cyclohexyl-2-benzothiazyl sulfenamide was significant and the optimum value of binary accelerator was suggested, respectively, at levels 0 and +1.

  11. Accelerate!

    Science.gov (United States)

    Kotter, John P

    2012-11-01

    The old ways of setting and implementing strategy are failing us, writes the author of Leading Change, in part because we can no longer keep up with the pace of change. Organizational leaders are torn between trying to stay ahead of increasingly fierce competition and needing to deliver this year's results. Although traditional hierarchies and managerial processes--the components of a company's "operating system"--can meet the daily demands of running an enterprise, they are rarely equipped to identify important hazards quickly, formulate creative strategic initiatives nimbly, and implement them speedily. The solution Kotter offers is a second system--an agile, networklike structure--that operates in concert with the first to create a dual operating system. In such a system the hierarchy can hand off the pursuit of big strategic initiatives to the strategy network, freeing itself to focus on incremental changes to improve efficiency. The network is populated by employees from all levels of the organization, giving it organizational knowledge, relationships, credibility, and influence. It can Liberate information from silos with ease. It has a dynamic structure free of bureaucratic layers, permitting a level of individualism, creativity, and innovation beyond the reach of any hierarchy. The network's core is a guiding coalition that represents each level and department in the hierarchy, with a broad range of skills. Its drivers are members of a "volunteer army" who are energized by and committed to the coalition's vividly formulated, high-stakes vision and strategy. Kotter has helped eight organizations, public and private, build dual operating systems over the past three years. He predicts that such systems will lead to long-term success in the 21st century--for shareholders, customers, employees, and companies themselves.

  12. Accelerating cosmologies and a phase transition in M-theory

    Energy Technology Data Exchange (ETDEWEB)

    Wohlfarth, Mattias N.R

    2003-06-19

    M-theory compactifies on a seven-dimensional time-dependent hyperbolic or flat space to a four-dimensional FLRW cosmology undergoing a period of accelerated expansion in Einstein conformal frame. The strong energy condition is violated by the scalar fields produced in the compactification, as is necessary to evade the no-go theorem for time-independent compactifications. The four-form field strength of eleven-dimensional supergravity smoothly switches on during the period of accelerated expansion in hyperbolic compactifications, whereas in flat compactifications, the three-form potential smoothly changes its sign. For small acceleration times, this behaviour is like a phase transition of the three-form potential, during which the cosmological scale factor approximately doubles.

  13. Accelerating Cosmologies and a Phase Transition in M-Theory

    CERN Document Server

    Wohlfarth, M N R

    2003-01-01

    M-theory compactifies on a seven-dimensional time-dependent hyperbolic or flat space to a four-dimensional FLRW cosmology undergoing a period of accelerated expansion in Einstein conformal frame. The strong energy condition is violated by the scalar fields produced in the compactification, as is necessary to evade the no-go theorem for time-independent compactifications. The four-form field strength of eleven-dimensional supergravity smoothly switches on during the period of accelerated expansion in hyperbolic compactifications, whereas in flat compactifications, the three-form potential smoothly changes its sign. For small acceleration times, this behaviour is like a phase transition of the three-form potential, during which the cosmological scale factor approximately doubles.

  14. On Memory Accelerated Signal Processing within Software Defined Radios

    CERN Document Server

    Pellegrini, Vincenzo; Di Dio, Mario

    2010-01-01

    Since J. Mitola's work in 1992, Software Defined Radios (SDRs) have been quite a hot topic in wireless systems research. Though many notable achievements were reported in the field, the scarcity of computational power on general purpose CPUs has always constrained their wide adoption in production environments. If conveniently applied within an SDR context, classical concepts known in computer science as space/time tradeoffs can be extremely helpful when trying to mitigate this problem. Inspired by and building on those concepts, this paper presents a novel SDR implementation technique which we call Memory Acceleration (MA) that makes extensive use of the memory resources available on a general purpose computing system, in order to accelerate signal computation. MA can provide substantial acceleration factors when applied to conventional SDRs without reducing their peculiar flexibility. As a practical proof of this, an example of MA applied in the real world to the ETSI DVB-T Viterbi decoder is provided. Actu...

  15. Influence of Accelerated Aging on Detonation Performance of Explosives

    Institute of Scientific and Technical Information of China (English)

    GAO Da-yuan; HUA Cheng; WANG Xiang; HAN Yong

    2010-01-01

    To understand the aging effects on detonation performances of explosives, an accelerated aging mechanism and effect of explosives were analyzed. Based on the thermo-gravimetric (TG) curves of explosives under the heat rate of 5, 10 and 20 K·min-1, the thermal decomposition activation energy, pre-exponential factor, mechanism function and kinetic equation of the explosives were calculated by Ozawa's equation and decomposition extents. Then, according to the derived kinetic equation, the density, composition and heat of formation of GI-1, PBX-1 and PBX-2 explosive in different decompo-sition extents were calculated at accelerated aging temperatures of 70 ℃ and 75 ℃, respectively. Furthermore, the detona-tion parameters of GI-1, PBX-1 and PBX-2 explosives were found out by means of VLWR code. The results show that after accelerated aging, the density are decrease, the detonation velocity and pressure are all decreased slightly.

  16. A preliminary design of the collinear dielectric wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.; Gai, W.; Doran, S.; Lindberg, R.; Power, J.G.; Strelnikov, N.; Sun, Y.; Trakhtenberg, E.; Vasserman, I. [ANL, Argonne, IL 60439 (United States); Jing, C.; Kanareykin, A.; Li, Y. [Euclid Techlabs LLC, Solon, OH 44139 (United States); Gao, Q. [Tsinghua University, Beijing (China); Shchegolkov, D.Y.; Simakov, E.I. [LANL, Los Alamos, NM 87545 (United States)

    2016-09-01

    A preliminary design of the multi-meter long collinear dielectric wakefield accelerator that achieves a highly efficient transfer of the drive bunch energy to the wakefields and to the witness bunch is considered. It is made from ~0.5 m long accelerator modules containing a vacuum chamber with dielectric-lined walls, a quadrupole wiggler, an rf coupler, and BPM assembly. The single bunch breakup instability is a major limiting factor for accelerator efficiency, and the BNS damping is applied to obtain the stable multi-meter long propagation of a drive bunch. Numerical simulations using a 6D particle tracking computer code are performed and tolerances to various errors are defined.

  17. Numeric Spectrum of Relic Gravitational Waves in Accelerating Universe

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yang; ZHAO Wen; YUAN Ye-Fei; XIA Tian-Yang

    2005-01-01

    @@ The accelerating expansion of the Universe in the present stage is a process that will change the spectrum of relic gravitational waves. Here we present a numerical calculation for the power spectrum of relic gravitational waves in the accelerating Universe. The results show that although the overall features of the power spectrum are similar to those in the non-accelerating models, the amplitude is smaller in order of 10-1. We also find that the spectrum is very sensitive to the index β of the inflationary expansion with the scale factor a(τ) ∝ |τ|1+β. With increase of β, the resulting spectrum tends to be flatter with more power on high frequencies, and the sensitivity of the second science run of the LIGO detectors puts a restriction on the parameterβ< -1.8. The influence of reheating followed by the inflation has been examined.

  18. Advanced Accelerator Concepts Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Wurtele, Jonathan S.

    2014-05-13

    physics motivation for our experiment, one that requires only a few dozen researchers but must effectively integrate plasma, accelerator, atomic, and fundamental physics, as well as combine numerous technologies in the control, manipulation, and measurement of neutral and non-neutral particles. The ELENA ring (to which we hope to contribute, should funding be provided) is expect, when completed, to significantly enhance the performance of antihydrogen trapping by increasing by a factor of 100 the number of antiprotons that can be successfully trapped and cooled. ELENA operation is scheduled to commence in 2017. In collaboration with LBNL scientists, we proposed a frictional cooling scheme. This is an alternative cooling method to that used by ELENA. It is less complicated, experimentally unproven, and produces a lower yield of cold antiprotons. Students and postdoctoral researchers work on the trapping, cooling, transport, and nonlinear dynamics of antiprotons bunches that are provided by the AD to ALPHA; they contribute to the operation of the experiment, to software development, and to the design and operation of experiments. Students are expected to spend at summers at CERN while taking courses; after completion of courses they typically reside at CERN for most of the half-year run. The Antiproton Decelerator [AD] at CERN, along with its experiments, is the only facility in the world where antiprotons can be trapped and cooled and combined with positrons to form cold antihydrogen, with the ultimate goal of studying CPT violation and, subsequently, gravitational interactions of antimatter. Beyond the ALPHA experiment, the group worked on beam physics problems including limits on the average current in a time-dependent period cathode and new methods to create longitudinally coherent high repetition rate soft x-ray sources and wide bandwidth mode locked x-ray lasers. We completed a detailed study of quantum mechanical effects in the transit time cooling of muons.

  19. Accelerated aging of polymer composite bridge materials

    Science.gov (United States)

    Carlson, Nancy M.; Blackwood, Larry G.; Torres, Lucinda L.; Rodriguez, Julio G.; Yoder, Timothy S.

    1999-05-01

    Accelerated aging research on samples of composite materials and candidate UV protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory. Durability results and sensor data form test with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  20. Accelerated Aging of Polymer Composite Bridge Materials

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Nancy Margaret; Blackwood, Larry Gene; Torres, Lucinda Laine; Rodriguez, Julio Gallardo; Yoder, Timothy Scott

    1999-03-01

    Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  1. Strong evidence for hadron acceleration in Tycho's supernova remnant

    Science.gov (United States)

    Morlino, G.; Caprioli, D.

    2012-02-01

    Context. Very recent gamma-ray observations of G120.1+1.4 (Tycho's) supernova remnant (SNR) by Fermi-LAT and VERITAS have provided new fundamental pieces of information for understanding particle acceleration and nonthermal emission in SNRs. Aims: We want to outline a coherent description of Tycho's properties in terms of SNR evolution, shock hydrodynamics, and multiwavelength emission by accounting for particle acceleration at the forward shock via first-order Fermi mechanism. Methods: We adopt here a quick and reliable semi-analytical approach to nonlinear diffusive shock acceleration. It includes magnetic field amplification due to resonant streaming instability and the dynamical backreaction on the shock of both cosmic rays (CRs) and self-generated magnetic turbulence. Results: We find that Tycho's forward shock accelerates protons up to at least 500 TeV, channelling into CRs about 10% of its kinetic energy. Moreover, the CR-induced streaming instability is consistent with all the observational evidence of very efficient magnetic field amplification (up to ~300 μG). In such a strong magnetic field, the velocity of the Alfvén waves scattering CRs in the upstream is expected to be enhanced and to make accelerated particles feel an effective compression factor lower than 4, in turn leading to an energy spectrum steeper than the standard prediction ∝ E-2. This effect is crucial for explaining GeV-to-TeV gamma-ray spectrum as the result of neutral pions decay produced in nuclear collisions between accelerated nuclei and the background gas. Conclusions: The self-consistency of such hadronic scenario, along with the inability of the concurrent leptonic mechanism (inverse Compton scattering of relativistic electrons on several photon backgrounds) to reproduce both the shape and the normalization of the detected gamma-ray emission, represents the first clear and direct radiative evidence that hadron acceleration occurs efficiently in young Galactic SNRs.

  2. The Radiological Research Accelerator Facility

    Energy Technology Data Exchange (ETDEWEB)

    Hall, E.J.

    1992-05-01

    The Radiological Research Accelerator Facility (RARAF) is based on a 4-MV Van de Graaff accelerator, which is used to generate a variety of well-characterized radiation beams for research in radiobiology, radiological physics, and radiation chemistry. It is part of the Center for Radiological Research (CRR) -- formerly the Radiological Research Laboratory (RRL) -- of Columbia University, and its operation is supported as a National Facility by the US Department of Energy (DOE). As such, RARAF is available to all potential users on an equal basis, and scientists outside the CRR are encouraged to submit proposals for experiments at RARAF. The operation of the Van de Graaff is supported by the DOE, but the research projects themselves must be supported separately. Experiments performed from May 1991--April 1992 are described.

  3. The Radiological Research Accelerator Facility

    Energy Technology Data Exchange (ETDEWEB)

    Hall, E.J.; Marino, S.A.

    1993-05-01

    The Radiological Research Accelerator Facility (RARAF) is based on a 4-MV Van de Graaff accelerator, which is used to generate a variety of well-characterized radiation beams for research in radiobiology, radiological physics, and radiation chemistry. It is part of the Center for Radiological Research (CRR) - formerly the Radiological Research Laboratory of Columbia University, and its operation is supported as a National Facility by the US Department of Energy (DOE). As such, RARAF is available to all potential users on an equal basis and scientists outside the CRR are encouraged to submit proposals for experiments at RARAF. The operation of the Van de Graaff is supported by the DOE, but the research projects themselves must be supported separately. This report provides a listing and brief description of experiments performed at RARAF during the May 1, 1992 through April 30, 1993.

  4. Accelerating Expansion of the Universe

    CERN Document Server

    Chakraborty, Writambhara

    2011-01-01

    This thesis concentrates on the accelerated expansion of the Universe recently explored by measurements of redshift and luminosity-distance relations of type Ia Supernovae. We have considered a model of the universe filled with modified Chaplygin gas and barotropic fluid. The role of dynamical cosmological constant has been explored with Modified Chaplygin Gas as the background fluid. Various phenomenological models for \\Lambda have been studied in presence of the gravitational constant G to be constant or time dependent. A new form of the well known Chaplygin gas model has been presented by introducing inhomogeneity in the EOS. This model explains w=-1 crossing. An interaction of this model with the scalar field has also been investigated through a phenomenological coupling function. Tachyonic field has been depicted as dark energy model to represent the present acceleration of the Universe. A mixture of the tachyonic fluid has been considered with Generalized Chaplygin Gas to show the role of the later as a...

  5. History of hadron therapy accelerators.

    Science.gov (United States)

    Degiovanni, Alberto; Amaldi, Ugo

    2015-06-01

    In the last 60 years, hadron therapy has made great advances passing from a stage of pure research to a well-established treatment modality for solid tumours. In this paper the history of hadron therapy accelerators is reviewed, starting from the first cyclotrons used in the thirties for neutron therapy and passing to more modern and flexible machines used nowadays. The technical developments have been accompanied by clinical studies that allowed the selection of the tumours which are more sensitive to this type of radiotherapy. This paper aims at giving a review of the origin and the present status of hadron therapy accelerators, describing the technological basis and the continuous development of this application to medicine of instruments developed for fundamental science. At the end the present challenges are reviewed.

  6. Hardware-Accelerated Simulated Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Laney, D; Callahan, S; Max, N; Silva, C; Langer, S; Frank, R

    2005-08-04

    We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take advantage of 32-bit floating point texture capabilities to obtain solutions to the radiative transport equation for X-rays. The hardware accelerated solutions are accurate enough to enable scientists to explore the experimental design space with greater efficiency than the methods currently in use. An unsorted hexahedron projection algorithm is presented for curvilinear hexahedral meshes that produces simulated radiographs in the absorption-only regime. A sorted tetrahedral projection algorithm is presented that simulates radiographs of emissive materials. We apply the tetrahedral projection algorithm to the simulation of experimental diagnostics for inertial confinement fusion experiments on a laser at the University of Rochester.

  7. Self accelerating electron Airy beams

    CERN Document Server

    Voloch-Bloch, Noa; Lilach, Yigal; Gover, Avraham; Arie, Ady

    2013-01-01

    We report the first experimental generation and observation of Airy beams of free electrons. The electron Airy beams are generated by diffraction of electrons through a nanoscale hologram, that imprints a cubic phase modulation on the beams' transverse plane. We observed the spatial evolution dynamics of an arc-shaped, self accelerating and shape preserving electron Airy beams. We directly observed the ability of electrons to self-heal, restoring their original shape after passing an obstacle. This electromagnetic method opens up new avenues for steering electrons, like their photonic counterparts, since their wave packets can be imprinted with arbitrary shapes or trajectories. Furthermore, these beams can be easily manipulated using magnetic or electric potentials. It is also possible to efficiently self mix narrow beams having opposite signs of acceleration, hence obtaining a new type of electron interferometer.

  8. Accelerating optimization by tracing valley

    Science.gov (United States)

    Li, Qing-Xiao; He, Rong-Qiang; Lu, Zhong-Yi

    2016-06-01

    We propose an algorithm to accelerate optimization when an objective function locally resembles a long narrow valley. In such a case, a conventional optimization algorithm usually wanders with too many tiny steps in the valley. The new algorithm approximates the valley bottom locally by a parabola that is obtained by fitting a set of successive points generated recently by a conventional optimization method. Then large steps are taken along the parabola, accompanied by fine adjustment to trace the valley bottom. The effectiveness of the new algorithm has been demonstrated by accelerating the Newton trust-region minimization method and the Levenberg-Marquardt method on the nonlinear fitting problem in exact diagonalization dynamical mean-field theory and on the classic minimization problem of the Rosenbrock's function. Many times speedup has been achieved for both problems, showing the high efficiency of the new algorithm.

  9. The US Muon Accelerator Program

    Energy Technology Data Exchange (ETDEWEB)

    Torun, Y.; /IIT, Chicago; Kirk, H.; /Brookhaven; Bross, A.; Geer, Steve; Shiltsev, Vladimir; /Fermilab; Zisman, M.; /LBL, Berkeley

    2010-05-01

    An accelerator complex that can produce ultra-intense beams of muons presents many opportunities to explore new physics. A facility of this type is unique in that, in a relatively straightforward way, it can present a physics program that can be staged and thus move forward incrementally, addressing exciting new physics at each step. At the request of the US Department of Energy's Office of High Energy Physics, the Neutrino Factory and Muon Collider Collaboration (NFMCC) and the Fermilab Muon Collider Task Force (MCTF) have recently submitted a proposal to create a Muon Accelerator Program that will have, as a primary goal, to deliver a Design Feasibility Study for an energy-frontier Muon Collider by the end of a 7 year R&D program. This paper presents a description of a Muon Collider facility and gives an overview of the proposal.

  10. Industrial Applications of Accelerator Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaesang; Park, Jaewon; Lee, Chanyoung; and others

    2013-02-15

    PEFP(Proton Engineering Frontier Project) put its aim on development of high power linear proton accelerator and its beam applications. So, it has, since late 1990's, accumulated accelerator and ion source technologies, supplied beam utilization service to related industry. As of now, right after 10 year long project(PEFP), many of its low energy beam technologies seem to be successfully utilized for industrial purpose to meet the market needs, especially in improvement of production process and manufacturing performance, new substance development, etc. In this context, it is high time to carry out in-depth industrialization development on PEFP's retained ion beam technology prowess: To help them diffused profitable markets as soon as possible. So, in this work, through verification on the industrialization feasibility by experiments, it is going to get it started, with cooperation of participatory company, to enter into markets with developed technology and products.

  11. Particle Accelerators for PET radionuclides

    DEFF Research Database (Denmark)

    Jensen, Mikael

    2012-01-01

    The requirements set for particle accelerators for production of radioactive isotopes for PET can easily be derived from first principles. The simple general need is for proton beams with energy in the region 10–20 MeV and current 20–100 microAmps. This is most reliably and cost-effectively achie......The requirements set for particle accelerators for production of radioactive isotopes for PET can easily be derived from first principles. The simple general need is for proton beams with energy in the region 10–20 MeV and current 20–100 microAmps. This is most reliably and cost...... different manufacturers will be discussed the light of what is actually needed for a given PET site operation. Alternatives to the conventional cyclotron have been proposed and tested but have at present very limited use. These alternatives will be discussed, as well as the future possibilities of supplying...

  12. Observational Probes of Cosmic Acceleration

    CERN Document Server

    Weinberg, David H; Eisenstein, Daniel J; Hirata, Christopher; Riess, Adam G; Rozo, Eduardo

    2012-01-01

    The accelerating expansion of the universe is the most surprising cosmological discovery in many decades, implying that the universe is dominated by some form of "dark energy" with exotic physical properties, or that Einstein's theory of gravity breaks down on cosmological scales. The profound implications of cosmic acceleration have inspired ambitious experimental efforts to measure the history of expansion and growth of structure with percent-level precision or higher. We review in detail the four most well established methods for making such measurements: Type Ia supernovae, baryon acoustic oscillations (BAO), weak gravitational lensing, and galaxy clusters. We pay particular attention to the systematic uncertainties in these techniques and to strategies for controlling them at the level needed to exploit "Stage IV" dark energy facilities such as BigBOSS, LSST, Euclid, and WFIRST. We briefly review a number of other approaches including redshift-space distortions, the Alcock-Paczynski test, and direct meas...

  13. Greece welcomes CERN Accelerator School

    CERN Multimedia

    CAS School

    2011-01-01

    The CERN Accelerator School (CAS) and the University of the Aegean jointly organised a course on intermediate-level Accelerator Physics in Chios, Greece, from 19 to 30 September, 2011.   CAS Students pose for a group photo in Chios, Greece. This course followed the established format of the intermediate school, with lectures in the mornings and specialised courses in the afternoons. The latter provided “hands-on” education and experience in three topics: “RF Measurement Techniques”, “Beam Instrumentation and Diagnostics” and “Optics Design and Correction”.  Participants selected one of the three courses and followed the chosen topic throughout the school. Guided studies and tutorials on core subjects, seminars and a poster session completed the programme. An excursion included a visit to the Nea Moni monastery, a guided tour of two medieval villages, Pyrgi and Mesta, and finished with a typical Greek me...

  14. Industrial applications of electron accelerators

    CERN Document Server

    Cleland, M R

    2006-01-01

    This paper addresses the industrial applications of electron accelerators for modifying the physical, chemical or biological properties of materials and commercial products by treatment with ionizing radiation. Many beneficial effects can be obtained with these methods, which are known as radiation processing. The earliest practical applications occurred during the 1950s, and the business of radiation processing has been expanding since that time. The most prevalent applications are the modification of many different plastic and rubber products and the sterilization of single-use medical devices. Emerging applications are the pasteurization and preservation of foods and the treatment of toxic industrial wastes. Industrial accelerators can now provide electron energies greater than 10 MeV and average beam powers as high as 700 kW. The availability of high-energy, high-power electron beams is stimulating interest in the use of X-rays (bremsstrahlung) as an alternative to gamma rays from radioactive nuclides.

  15. Accelerating structure with linear excitation

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, J.; Srinivasan-Rao, T.

    1988-03-01

    The switched power linac (SPL) structures require a ring-shaped laser beam pulse of uniform intensity to avoid transverse field components of the accelerating field at the center. In order to also utilize the reflection of the outgoing EM wave, the switching element has to be very close to the outer edge of the structure to ensure nearly synchronous superposition at the beam hole with the original inward going wave. It is sometimes easier to produce linear (flat) laser beams, e.g., from powerful excimer lasers which have beams of rectangular cross section. Such flat beams could be used to excite linear photocathode switches or be used to produce flat electron beam pulses in electron sources. In this paper, an accelerator structure is proposed which may be considered a variant of the SPL disk structure, but could be used with linear beams. The structure utilizes a double parabolic horn. 8 refs., 9 figs.

  16. String worldsheet for accelerating quark

    Science.gov (United States)

    Hubeny, Veronika E.; Semenoff, Gordon W.

    2015-10-01

    We consider the AdS bulk dual to an external massive quark in SYM following an arbitrary trajectory on Minkowski background. While a purely outgoing boundary condition on the gluonic field allows one to express the corresponding string worldsheet in a closed form, the setup has curious consequences. In particular, we argue that any quark whose trajectory on flat spacetime approaches that of a light ray in the remote past (as happens e.g. in the case of uniform acceleration) must necessarily be accompanied by an anti-quark. This is puzzling from the field theory standpoint, since one would expect that a sole quark following any timelike trajectory should be allowed. We explain the resolution in terms of boundary and initial conditions. We analyze the configuration in global AdS, which naturally suggests a modification to the boundary conditions allowing for a single accelerated quark without accompanying anti-quark. We contrast this resolution with earlier proposals.

  17. Accelerating Around an Unbanked Curve

    Science.gov (United States)

    Mungan, Carl E.

    2006-02-01

    The December 2004 issue of TPT presented a problem concerning how a car should accelerate around an unbanked curve of constant radius r starting from rest if it is to avoid skidding. Interestingly enough, two solutions were proffered by readers.2 The purpose of this note is to compare and contrast the two approaches. Further experimental investigation of various turning strategies using a remote-controlled car and overhead video analysis could make for an interesting student project.

  18. Geometry for the accelerating universe

    CERN Document Server

    Punzi, R; Wohlfarth, M N R; Punzi, Raffaele; Schuller, Frederic P.; Wohlfarth, Mattias N.R.

    2006-01-01

    The Lorentzian spacetime metric is replaced by an area metric which naturally emerges as a generalized geometry in quantum string and gauge theory. Employing the area metric curvature scalar, the gravitational Einstein-Hilbert action is re-interpreted as dynamics for an area metric. Without the need for dark energy or fine-tuning, area metric cosmology explains the observed small acceleration of the late Universe.

  19. Accelerator x-ray sources

    CERN Document Server

    Talman, Richard

    2007-01-01

    This first book to cover in-depth the generation of x-rays in particle accelerators focuses on electron beams produced by means of the novel Energy Recovery Linac (ERL) technology. The resulting highly brilliant x-rays are at the centre of this monograph, which continues where other books on the market stop. Written primarily for general, high energy and radiation physicists, the systematic treatment adopted by the work makes it equally suitable as an advanced textbook for young researchers.

  20. Status of JAERI tandem accelerator

    Energy Technology Data Exchange (ETDEWEB)

    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)

  1. An accelerator worth fighting for

    CERN Multimedia

    1996-01-01

    Financial pressures from member states have upset the calculations of the European Laboratory for Particle Physics's (CERN) major accelerator, the Large Hadron Collider (LHC). Despite preference for domestic high energy programs, CERN members accord high priority to LHC physics. Converting to a global facility can help spread the high annual cost of subscription. But given the political realities, a revision of the LHC project appears more feasible. CERN's management needs to deploy its skills to overcome the financial obstacles to the facility.

  2. Symplectic maps for accelerator lattices

    Energy Technology Data Exchange (ETDEWEB)

    Warnock, R.L.; Ruth, R.; Gabella, W.

    1988-05-01

    We describe a method for numerical construction of a symplectic map for particle propagation in a general accelerator lattice. The generating function of the map is obtained by integrating the Hamilton-Jacobi equation as an initial-value problem on a finite time interval. Given the generating function, the map is put in explicit form by means of a Fourier inversion technique. We give an example which suggests that the method has promise. 9 refs., 9 figs.

  3. Self-accelerating Warped Braneworlds

    Energy Technology Data Exchange (ETDEWEB)

    Carena, Marcela; Lykken, Joseph; /Fermilab; Park, Minjoon; /UC, Davis; Santiago, Jose; /Fermilab

    2006-11-01

    Braneworld models with induced gravity have the potential to replace dark energy as the explanation for the current accelerating expansion of the Universe. The original model of Dvali, Gabadadze and Porrati (DGP) demonstrated the existence of a ''self-accelerating'' branch of background solutions, but suffered from the presence of ghosts. We present a new large class of braneworld models which generalize the DGP model. Our models have negative curvature in the bulk, allow a second brane, and have general brane tensions and localized curvature terms. We exhibit three different kinds of ghosts, associated to the graviton zero mode, the radion, and the longitudinal components of massive graviton modes. The latter two species occur in the DGP model, for negative and positive brane tension respectively. In our models, we find that the two kinds of DGP ghosts are tightly correlated with each other, but are not always linked to the feature of self-acceleration. Our models are a promising laboratory for understanding the origins and physical meaning of braneworld ghosts, and perhaps for eliminating them altogether.

  4. Time derivative of earthquake acceleration

    Institute of Scientific and Technical Information of China (English)

    Mai Tong; Guo-Quan Wang; George C.Lee

    2005-01-01

    Unlike acceleration, velocity, and displacement, the time derivative of acceleration (TDoA) of ground motion has not been extensively studied. In this paper, the basic characteristics of TDoA are evaluated based on records from the 1999Chi-Chi, earthquake (Mw 7.6) and one of its aftershocks (Mw 6.2). It is found that the maximum TDoA at a free-field station was over 31,200 crm/s3 (31.8 g/s); and the duration of "strong" TDoA, between the first and the last time points exceeding 2,000 cm/s3 (2 g/s), was almost one minute near the epicenter area. Since ground TDoA sensors are not commonly available,the time series are calculated by direct numerical differentiation of acceleration time series. Relative error analysis shows that the error is non-transitive and total error is within 4%. The density function of TDoA amplitude, frequency content and spatial distribution of peak ground jerk (PGJ) are evaluated. The study also includes examination of some TDoA responses from a seven-story building and comparison of ground TDoA with the limit TDoA used in the transportation industry for ride comfort. Some potential impacts of TDoA on humans have also been reviewed.

  5. Compensation Techniques in Accelerator Physics

    Energy Technology Data Exchange (ETDEWEB)

    Sayed, Hisham Kamal [Old Dominion Univ., Norfolk, VA (United States)

    2011-05-01

    Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

  6. Analytical tools in accelerator physics

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.N.

    2010-09-01

    This paper is a sub-set of my lectures presented in the Accelerator Physics course (USPAS, Santa Rosa, California, January 14-25, 2008). It is based on my notes I wrote during period from 1976 to 1979 in Novosibirsk. Only few copies (in Russian) were distributed to my colleagues in Novosibirsk Institute of Nuclear Physics. The goal of these notes is a complete description starting from the arbitrary reference orbit, explicit expressions for 4-potential and accelerator Hamiltonian and finishing with parameterization with action and angle variables. To a large degree follow logic developed in Theory of Cyclic Particle Accelerators by A.A.Kolmensky and A.N.Lebedev [Kolomensky], but going beyond the book in a number of directions. One of unusual feature is these notes use of matrix function and Sylvester formula for calculating matrices of arbitrary elements. Teaching the USPAS course motivated me to translate significant part of my notes into the English. I also included some introductory materials following Classical Theory of Fields by L.D. Landau and E.M. Liftsitz [Landau]. A large number of short notes covering various techniques are placed in the Appendices.

  7. Injector Design for Advanced Accelerators

    Science.gov (United States)

    Henestroza, Enrique; Faltens, A.

    1996-11-01

    Accelerator designs intended to provide acceleration at a much lower cost per Joule than the ILSE or ELISE designs are under study. For these designs, which typically have many beams, an injector of significantly lower cost is needed. A goal, which from our design appears to be achievable, is to reduce the transverse dimension to half that of the 2 MeV, 800 mA ILSE injector(E. Henestroza, ``Injectors for Heavy Ion Fusion", Proc. of the 11th International Wkshp. on Laser Interaction and Related Plasma Phenomena, 1993.) while generating about the same current. A single channel of a lower cost injector includes an 800 kV column, accelerating a 700 mA beam extracted from a potassium source of 4 cm radius by a 120 kV electrode. The beam passes into a superconducting 7 T solenoid of 15 cm aperture and 15 cm length. This high-field solenoid provides the focusing needed for a small beam without increasing the electric field gradient. The injector and its matching section, also designed, fit within a 12 cm radius, which is small enough to allow construction of attractive multi-beam injectors. We will present solutions for the generation and transport of 700 mA potassium beams of up to 1.6 MeV within the same transverse constraint.

  8. Low voltage electron beam accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ochi, Masafumi [Iwasaki Electric Co., Ltd., Tokyo (Japan)

    2003-02-01

    Widely used electron accelerators in industries are the electron beams with acceleration voltage at 300 kV or less. The typical examples are shown on manufactures in Japan, equipment configuration, operation, determination of process parameters, and basic maintenance requirement of the electron beam processors. New electron beam processors with acceleration voltage around 100 kV were introduced maintaining the relatively high dose speed capability of around 10,000 kGy x mpm at production by ESI (Energy Science Inc. USA, Iwasaki Electric Group). The application field like printing and coating for packaging requires treating thickness of 30 micron or less. It does not require high voltage over 110 kV. Also recently developed is a miniature bulb type electron beam tube with energy less than 60 kV. The new application area for this new electron beam tube is being searched. The drive force of this technology to spread in the industries would be further development of new application, process and market as well as the price reduction of the equipment, upon which further acknowledgement and acceptance of the technology to societies and industries would entirely depend. (Y. Tanaka)

  9. On the solutions to accelerating cosmologies

    CERN Document Server

    Ito, M

    2003-01-01

    Motivated by recent accelerating cosmological model, we derive the solutions to vacuum Einstein equation in $(d+1)$-dimensional Minkowski space with $n$-dimensional hyperbolic manifold. The conditions of accelerating expansion are given in such a set up.

  10. Symposium report on frontier applications of accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Parsa, Z. [ed.

    1993-09-28

    This report contains viewgraph material on the following topics: Electron-Positron Linear Colliders; Unconventional Colliders; Prospects for UVFEL; Accelerator Based Intense Spallation; Neutron Sources; and B Physics at Hadron Accelerators with RHIC as an Example.

  11. Snowmass 2013 Computing Frontier: Accelerator Science

    CERN Document Server

    Spentzouris, P; Joshi, C; Amundson, J; An, W; Bruhwiler, D L; Cary, J R; Cowan, B; Decyk, V K; Esarey, E; Fonseca, R A; Friedman, A; Geddes, C G R; Grote, D P; Kourbanis, I; Leemans, W P; Lu, W; Mori, W B; Ng, C; Qiang, Ji; Roberts, T; Ryne, R D; Schroeder, C B; Silva, L O; Tsung, F S; Vay, J -L; Vieira, J

    2013-01-01

    This is the working summary of the Accelerator Science working group of the Computing Frontier of the Snowmass meeting 2013. It summarizes the computing requirements to support accelerator technology in both Energy and Intensity Frontiers.

  12. Accelerated Cure Project for Multiple Sclerosis

    Science.gov (United States)

    ... main content Accelerating research toward a cure for multiple sclerosis Home Contact Us Search form Search Connect Volunteer ... is to accelerate efforts toward a cure for multiple sclerosis by rapidly advancing research that determines its causes ...

  13. Berkeley Lab Laser Accelerator (BELLA) facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Berkeley Lab Laser Accelerator (BELLA) facility (formerly LOASIS) develops advanced accelerators and radiation sources. High gradient (1-100 GV/m) laser-plasma...

  14. A Critical Theory Perspective on Accelerated Learning.

    Science.gov (United States)

    Brookfield, Stephen D.

    2003-01-01

    Critically analyzes accelerated learning using concepts from Herbert Marcuse (rebellious subjectivity) and Erich Fromm (automaton conformity). Concludes that, by providing distance and separation, accelerated learning has more potential to stimulate critical autonomous thought. (SK)

  15. Extremely Fast Acceleration of Cosmic Rays in a Supernova Remnant

    Energy Technology Data Exchange (ETDEWEB)

    Uchiyama, Y.; Aharonian, F.A.; Tanaka, T.; Takahashi, T.; Maeda, Y.; /JAERI, Tokai /Dublin Inst. /Heidelberg, Max Planck Inst. /SLAC

    2007-10-23

    Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through magnetohydrodynamic waves generated by cosmic rays. Here we report a discovery of the brightening and decay of X-ray hot spots in the shell of theSNRRXJ1713.723946 on a one-year timescale. This rapid variability shows that the X-rays are produced by ultrarelativistic electrons through a synchrotron process and that electron acceleration does indeed take place in a strongly magnetized environment, indicating amplification of the magnetic field by a factor of more than 100. The X-ray variability also implies that we have witnessed the ongoing shock-acceleration of electrons in real time. Independently, broadband X-ray spectrometric measurements of RXJ1713.723946 indicate that electron acceleration proceeds in the most effective ('Bohm-diffusion') regime. Taken together, these two results provide a strong argument for acceleration of protons and nuclei to energies of 1 PeV (10{sup 15} eV) and beyond in young supernova remnants.

  16. Electron Acceleration in Contracting Magnetic Islands during Solar Flares

    Science.gov (United States)

    Borovikov, D.; Tenishev, V.; Gombosi, T. I.; Guidoni, S. E.; DeVore, C. R.; Karpen, J. T.; Antiochos, S. K.

    2017-01-01

    Electron acceleration in solar flares is well known to be efficient at generating energetic particles that produce the observed bremsstrahlung X-ray spectra. One mechanism proposed to explain the observations is electron acceleration within contracting magnetic islands formed by magnetic reconnection in the flare current sheet. In a previous study, a numerical magnetohydrodynamic simulation of an eruptive solar flare was analyzed to estimate the associated electron acceleration due to island contraction. That analysis used a simple analytical model for the island structure and assumed conservation of the adiabatic invariants of particle motion. In this paper, we perform the first-ever rigorous integration of the guiding-center orbits of electrons in a modeled flare. An initially isotropic distribution of particles is seeded in a contracting island from the simulated eruption, and the subsequent evolution of these particles is followed using guiding-center theory. We find that the distribution function becomes increasingly anisotropic over time as the electrons’ energy increases by up to a factor of five, in general agreement with the previous study. In addition, we show that the energized particles are concentrated on the Sunward side of the island, adjacent to the reconnection X-point in the flare current sheet. Furthermore, our analysis demonstrates that the electron energy gain is dominated by betatron acceleration in the compressed, strengthened magnetic field of the contracting island. Fermi acceleration by the shortened field lines of the island also contributes to the energy gain, but it is less effective than the betatron process.

  17. Construction of FFAG Accelerators in KURRI for ADS Study

    CERN Document Server

    Tanigaki, Minoru; Inoue, Makoto; Ishi, Yoshihiro; Machida, Shinji; Mishima, Kaichiro; Mori, Yoshiharu; Shiroya, Seiji

    2004-01-01

    KART (Kumatori Accelerator driven Reactor Test) project is in progress at Kyoto University Research Reactor Institute (KURRI) from the fiscal year of 2002. The purposes of this project is the feasibility study of ADS, such as studying the effect of incident neutron energy on the effective multiplication factor of the subcritical nuclear fuel system. We are now constructing a proton FFAG accelerator complex as a neutron production driver for this project. Our accelerator complex consists of a 2.5 MeV FFAG with induction acceleration as an injector, 20 MeV and 150 MeV FFAGs with RF acceleration as a booster and a main ring, respectively. Our FFAG injector is a spiral sector type with 32 trim coils to produce a magnetic field of variable field index. Both booster and main rings are the radial sector type in which the field index is determined by the shape of pole-face. The test operations of the injector and the whole FFAG complex are expected around the spring and summer in 2005, respectively. Then this FFAG co...

  18. Extremely fast acceleration of cosmic rays in a supernova remnant.

    Science.gov (United States)

    Uchiyama, Yasunobu; Aharonian, Felix A; Tanaka, Takaaki; Takahashi, Tadayuki; Maeda, Yoshitomo

    2007-10-04

    Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through magnetohydrodynamic waves generated by cosmic rays. Here we report a discovery of the brightening and decay of X-ray hot spots in the shell of the SNR RX J1713.7-3946 on a one-year timescale. This rapid variability shows that the X-rays are produced by ultrarelativistic electrons through a synchrotron process and that electron acceleration does indeed take place in a strongly magnetized environment, indicating amplification of the magnetic field by a factor of more than 100. The X-ray variability also implies that we have witnessed the ongoing shock-acceleration of electrons in real time. Independently, broadband X-ray spectrometric measurements of RX J1713.7-3946 indicate that electron acceleration proceeds in the most effective ('Bohm-diffusion') regime. Taken together, these two results provide a strong argument for acceleration of protons and nuclei to energies of 1 PeV (10(15) eV) and beyond in young supernova remnants.

  19. Tuning and Matching of Constant Impedance Travelling Wave Accelerating Structure

    Institute of Scientific and Technical Information of China (English)

    YANG; Jing-he; ZHU; Zhi-bin; WU; Qing-feng; ZENG; Zi-qiang; WANG; Xiu-long; ZHOU; Wen-zhen

    2015-01-01

    As the penetration depth of electron accelerated by 10MeV electron irradiating accelerator is deep,and the accelerator has broad application prospects.The performance of the accelerator is influenced,to a great extent,by the traveling wave accelerating tube,which is the core component of the accelerator.To develop the accelerator

  20. Resolving beam transport problems in electrostatic accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Larson, J.D.

    1977-01-01

    A review is given of problem areas in beam transmission which are frequently encountered during the design, operation and upgrading of electrostatic accelerators. Examples are provided of analytic procedures that clarify accelerator ion optics and lead to more effective beam transport. Suggestions are made for evaluating accelerator design with the goal of improved performance.

  1. 多因素综合海洋气候模拟加速试验技术在紧固件表面处理工艺筛选中的应用%Application of Multi-factor Integrated Simulation of Marine Climate and Acceleration Test Technologies in Screening of Fastener Surface Treatment Technologies

    Institute of Scientific and Technical Information of China (English)

    王俊芳; 李希; 殷宗莲; 杨晓然

    2016-01-01

    目的:进行表面处理工艺筛选。方法采用海洋气候多因素综合模拟加速试验技术,对镀锌三价铬钝化、镀锌六价铬钝化、镀锌镍合金、无铬锌铝涂层、拉孚铼工艺和石墨烯涂层6种汽车紧固件表面处理工艺进行试验。测定保护层初期腐蚀、保护层腐蚀10%(面积)和基体金属腐蚀10%(面积)的时间,根据检测数据评价上述工艺的保护性能并进行优劣排序。与万宁站户外暴露试验结果对比分析,验证筛选结果的正确性,同时评价海洋气候多因素综合模拟加速试验技术的加速性和相关性。结果6种表面处理工艺出现保护层初期腐蚀的时间分别为24、48、48、48、144、72 h;保护层腐蚀10%(面积)的时间分别为48、72、72、72、216、144 h;基体金属腐蚀的时间分别为216、168、432、432、432、216 h。腐蚀外观形貌变化过程与户外暴露试验相似,平均加速倍率为21。结论上述工艺保护性能优劣排序为拉孚铼工艺、无铬锌铝涂层、锌镍合金镀层、石墨烯、镀锌三价铬钝化和镀锌六价铬钝化。海洋气候多因素综合模拟加速试验技术与户外暴露试验结果相比具有高加速性和良好相关性,筛选结果正确。%Objective To screen surface treatment technologies. Methods Six kinds of automobile fastener surface treatment technologies, trivalence chromium passivated zinc plating, hexad chromium passivated zinc plating, zinc-nickel alloys plating, chromium free zinc aluminum plating, LAFRE® , and Graphene coating, were tested using a new technology—multi-factor simula-tion of marine climate and acceleration test technology. Initial corrosion time, the time of 10% surface treatment area corrosion, and the time of 10% base metal area corrosion were measured with net eye inspection method. The protection ability of the above surface treatment technologies was evaluated with inspection data. The correctness of the

  2. High-energy cosmic-ray acceleration

    CERN Document Server

    Bustamante, M; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M; von Steinkirch, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi acceleration, though not entirely satisfactory, is the most promising mechanism for explaining the ultra-high-energy cosmic-ray flux.

  3. Health physics practices at research accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R.H.

    1976-02-01

    A review is given of the uses of particle accelerators in health physics, the text being a short course given at the Health Physics Society Ninth Midyear Topical Symposium in February, 1976. Topics discussed include: (1) the radiation environment of high energy accelerators; (2) dosimetry at research accelerators; (3) shielding; (4) induced activity; (5) environmental impact of high energy accelerators; (6) population dose equivalent calculation; and (7) the application of the ''as low as practicable concept'' at accelerators. (PMA)

  4. Accelerator Technology Division progress report, FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  5. Deuterium accelerator experiments for APT.

    Energy Technology Data Exchange (ETDEWEB)

    Causey, Rion A. (Sandia National Laboratories, Livermore, CA); Hertz, Kristin L. (Sandia National Laboratories, Livermore, CA); Cowgill, Donald F. (Sandia National Laboratories, Livermore, CA)

    2005-08-01

    Sandia National Laboratories in California initiated an experimental program to determine whether tritium retention in the tube walls and permeation through the tubes into the surrounding coolant water would be a problem for the Accelerator Production of Tritium (APT), and to find ways to mitigate the problem, if it existed. Significant holdup in the tube walls would limit the ability of APT to meet its production goals, and high levels of permeation would require a costly cleanup system for the cooling water. To simulate tritium implantation, a 200 keV accelerator was used to implant deuterium into Al 6061-T and SS3 16L samples at temperatures and particle fluxes appropriate for APT, for times varying between one week and five months. The implanted samples were characterized to determine the deuterium retention and Permeation. During the implantation, the D(d,p)T nuclear reaction was used to monitor the build-up of deuterium in the implant region of the samples. These experiments increased in sophistication, from mono-energetic deuteron implants to multi-energetic deuteron and proton implants, to more accurately reproduce the conditions expected in APT. Micron-thick copper, nickel, and anodized aluminum coatings were applied to the front surface of the samples (inside of the APT walls) in an attempt to lower retention and permeation. The reduction in both retention and permeation produced by the nickel coatings, and the ability to apply them to the inside of the APT tubes, indicate that both nickel-coated Al 6061-T6 and nickel-coated SS3 16L tubes would be effective for use in APT. The results of this work were submitted to the Accelerator Production of Tritium project in document number TPO-E29-Z-TNS-X-00050, APT-MP-01-17.

  6. Accelerated Adaptive MGS Phase Retrieval

    Science.gov (United States)

    Lam, Raymond K.; Ohara, Catherine M.; Green, Joseph J.; Bikkannavar, Siddarayappa A.; Basinger, Scott A.; Redding, David C.; Shi, Fang

    2011-01-01

    The Modified Gerchberg-Saxton (MGS) algorithm is an image-based wavefront-sensing method that can turn any science instrument focal plane into a wavefront sensor. MGS characterizes optical systems by estimating the wavefront errors in the exit pupil using only intensity images of a star or other point source of light. This innovative implementation of MGS significantly accelerates the MGS phase retrieval algorithm by using stream-processing hardware on conventional graphics cards. Stream processing is a relatively new, yet powerful, paradigm to allow parallel processing of certain applications that apply single instructions to multiple data (SIMD). These stream processors are designed specifically to support large-scale parallel computing on a single graphics chip. Computationally intensive algorithms, such as the Fast Fourier Transform (FFT), are particularly well suited for this computing environment. This high-speed version of MGS exploits commercially available hardware to accomplish the same objective in a fraction of the original time. The exploit involves performing matrix calculations in nVidia graphic cards. The graphical processor unit (GPU) is hardware that is specialized for computationally intensive, highly parallel computation. From the software perspective, a parallel programming model is used, called CUDA, to transparently scale multicore parallelism in hardware. This technology gives computationally intensive applications access to the processing power of the nVidia GPUs through a C/C++ programming interface. The AAMGS (Accelerated Adaptive MGS) software takes advantage of these advanced technologies, to accelerate the optical phase error characterization. With a single PC that contains four nVidia GTX-280 graphic cards, the new implementation can process four images simultaneously to produce a JWST (James Webb Space Telescope) wavefront measurement 60 times faster than the previous code.

  7. Analysis of the change of cartilage matrix components and related growth factors and inflammatory factors in temporomandibular joint affecting under sustained high acceleration%持续性高正加速度下颞下颌关节软骨基质成分与相关炎性因子的mRNA变化

    Institute of Scientific and Technical Information of China (English)

    陈新; 栗洪师; 冯岩; 尹音; 曹均凯

    2015-01-01

    目的:建立不同持续性高正加速度(+Gz)环境下的动物模型,研究颞颌关节紊乱病(temporomandibular joint disorder,TMD)软骨关节基质成分Ⅱ型胶原、多糖聚糖体、胶原酶,以及IGF-1、TGF-β1、TNF-α、IL-2与IL-3的变化情况。方法分离并体外培养正常与+Gz下的颞下颌软骨细胞,提取总mRNA,荧光定量PCR检测。结果Ⅱ型胶原、多糖聚糖体、胶原酶,以及IGF-1、TGF-β1明显减少,TNF-α、IL-2与IL-3显著增高。结论在+Gz下,颞下颌关节软骨基质成分受到严重影响,修复能力下降,炎性反应增加。%Objective To investigate possible changes of cartilage matrix components typeⅡcollagen, polysaccharides, chitosan body and IGF-1, collagenase TGF-β1, TNF-α, IL-2 and IL-3 on temporomandibular joint disorder (TMD) under the establishment of different persistent high acceleration (+Gz) animal model of environment and the different activated time condition. Methods 36 Rats were randomly divided into 3 groups: Sham group(n=12), +5 Gz group(n=12), and +10 Gz group(n=12), isolated and temporomandibular cartilage cells of normal and high acceleration in vitro, extraction of total mRNA, fluorescence quantitative PCR detection. Results TypeⅡcollagen, polysaccharides, chitosan body and IGF-1, collagenase TGF-β1 decreased significantly, while TNF-α, IL-2 and IL-3 increased significantly. Conclusion The decrease of collagen type Ⅱ, proteoglycans, collagenase, IGF-1, TGF-β1 and increase of IL-2, IL-3 could be very important reasons for the reconstruction and inflammation reaction of proteoglycans induced by repeated +Gz stresses on temporomandibular joint.

  8. Microwave View on Particle Acceleration in Flares

    CERN Document Server

    Fleishman, Gregory D

    2013-01-01

    The thermal-to-nonthermal partition was found to vary greatly from one flare to another resulting in a broad variety of cases from 'heating without acceleration' to 'acceleration without heating'. Recent analysis of microwave data of these differing cases suggests that a similar acceleration mechanism, forming a power-law nonthermal tail up to a few MeV or even higher, operates in all the cases. However, the level of this nonthermal spectrum compared to the original thermal distribution differs significantly from one case to another, implying a highly different thermal-to-nonthermal energy partition in various cases. This further requires a specific mechanism capable of extracting the charged particles from the thermal pool and supplying them to a bulk acceleration process to operate in flares \\textit{in addition} to the bulk acceleration process itself, which, in contrast, efficiently accelerates the seed particles, while cannot accelerate the thermal particles. Within this 'microwave' view on the flare ener...

  9. Multi-beam linear accelerator EVT

    Energy Technology Data Exchange (ETDEWEB)

    Teryaev, Vladimir E., E-mail: vladimir_teryaev@mail.ru [Omega-P, Inc., New Haven, CT 06510 (United States); Kazakov, Sergey Yu. [Fermilab, Batavia, IL 60510 (United States); Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT 06510 (United States); Yale University, New Haven, CT 06511 (United States)

    2016-09-01

    A novel electron multi-beam accelerator is presented. The accelerator, short-named EVT (Electron Voltage Transformer) belongs to the class of two-beam accelerators. It combines an RF generator and essentially an accelerator within the same vacuum envelope. Drive beam-lets and an accelerated beam are modulated in RF modulators and then bunches pass into an accelerating structure, comprising uncoupled with each other and inductive tuned cavities, where the energy transfer from the drive beams to the accelerated beam occurs. A phasing of bunches is solved by choice correspond distances between gaps of the adjacent cavities. Preliminary results of numerical simulations and the initial specification of EVT operating in S-band, with a 60 kV gun and generating a 2.7 A, 1.1 MV beam at its output is presented. A relatively high efficiency of 67% and high design average power suggest that EVT can find its use in industrial applications.

  10. Cosmic-ray acceleration in young protostars

    CERN Document Server

    Padovani, Marco; Marcowith, Alexandre; Ferrière, Katia

    2015-01-01

    The main signature of the interaction between cosmic rays and molecular clouds is the high ionisation degree. This decreases towards the densest parts of a cloud, where star formation is expected, because of energy losses and magnetic effects. However recent observations hint to high levels of ionisation in protostellar systems, therefore leading to an apparent contradiction that could be explained by the presence of energetic particles accelerated within young protostars. Our modelling consists of a set of conditions that has to be satisfied in order to have an efficient particle acceleration through the diffusive shock acceleration mechanism. We find that jet shocks can be strong accelerators of protons which can be boosted up to relativistic energies. Another possibly efficient acceleration site is located at protostellar surfaces, where shocks caused by impacting material during the collapse phase are strong enough to accelerate protons. Our results demonstrate the possibility of accelerating particles du...

  11. Introduction to Particle Acceleration in the Cosmos

    Science.gov (United States)

    Gallagher, D. L.; Horwitz, J. L.; Perez, J.; Quenby, J.

    2005-01-01

    Accelerated charged particles have been used on Earth since 1930 to explore the very essence of matter, for industrial applications, and for medical treatments. Throughout the universe nature employs a dizzying array of acceleration processes to produce particles spanning twenty orders of magnitude in energy range, while shaping our cosmic environment. Here, we introduce and review the basic physical processes causing particle acceleration, in astrophysical plasmas from geospace to the outer reaches of the cosmos. These processes are chiefly divided into four categories: adiabatic and other forms of non-stochastic acceleration, magnetic energy storage and stochastic acceleration, shock acceleration, and plasma wave and turbulent acceleration. The purpose of this introduction is to set the stage and context for the individual papers comprising this monograph.

  12. Future HEP Accelerators: The US Perspective

    CERN Document Server

    Bhat, Pushpalatha

    2015-01-01

    Accelerator technology has advanced tremendously since the introduction of accelerators in the 1930s, and particle accelerators have become indispensable instruments in high energy physics (HEP) research to probe Nature at smaller and smaller distances. At present, accelerator facilities can be classified into Energy Frontier colliders that enable direct discoveries and studies of high mass scale particles and Intensity Frontier accelerators for exploration of extremely rare processes, usually at relatively low energies. The near term strategies of the global energy frontier particle physics community are centered on fully exploiting the physics potential of the Large Hadron Collider (LHC) at CERN through its high-luminosity upgrade (HL-LHC), while the intensity frontier HEP research is focused on studies of neutrinos at the MW-scale beam power accelerator facilities, such as Fermilab Main Injector with the planned PIP-II SRF linac project. A number of next generation accelerator facilities have been proposed...

  13. Electron Acceleration by Transient Ion Foreshock Phenomena

    Science.gov (United States)

    Wilson, L. B., III; Turner, D. L.

    2015-12-01

    Particle acceleration is a topic of considerable interest in space, laboratory, and astrophysical plasmas as it is a fundamental physical process to all areas of physics. Recent THEMIS [e.g., Turner et al., 2014] and Wind [e.g., Wilson et al., 2013] observations have found evidence for strong particle acceleration at macro- and meso-scale structures and/or pulsations called transient ion foreshock phenomena (TIFP). Ion acceleration has been extensively studied, but electron acceleration has received less attention. Electron acceleration can arise from fundamentally different processes than those affecting ions due to differences in their gyroradii. Electron acceleration is ubiquitous, occurring in the solar corona (e.g., solar flares), magnetic reconnection, at shocks, astrophysical plasmas, etc. We present new results analyzing the dependencies of electron acceleration on the properties of TIFP observed by the THEMIS spacecraft.

  14. ACFA and IPAC announce accelerator prizes

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Steve Myers, CERN's Director for Accelerators and Technology. The Asian Committee for Future Accelerators (ACFA) has joined forces with the first International Particle Accelerator Conference, IPAC’10, to award prizes for outstanding work in the field of accelerators. The conference replaces the regional conferences of the Americas, Europe and Asia and will be hosted by the three regions on a rotational basis (see CERN Courier). The ACFA/IPAC’10 Prizes Selection Committee, chaired by Won Namkung of Pohang Accelerator Laboratory, decided on the prizes and the names of the winners at a meeting on 20 January. The awards will be made during IPAC’10, which will be held in Kyoto on 23-28 May. Jie Wei. (Courtesy Tsinghua University.) Steve Myers, Director for Accelerators and Technology at CERN, receives an Achievement Prize for Outstanding Work in the Accelerator Field with no Age Limit “for his numerous outstanding contributions to the design, construction, commissio...

  15. Plasma Channel Guided Laser Wakefield Accelerator

    CERN Document Server

    Geddes, C G

    2005-01-01

    High quality electron beams (several 109 electrons above 80 MeV energy with percent energy spread and low divergence) have been produced for the first time in a compact, high gradient, all-optical laser accelerator by extending the interaction distance using a pre-formed plasma density channel to guide the drive laser pulse. Laser-driven accelerators, in which particles are accelerated by the electric field of a plasma wave (wake) driven by the radiation pressure of an intense laser, have over the past decade demonstrated accelerating fields thousands of times greater than those achievable in conventional radio-frequency accelerators. This has spurred interest in them as compact next- generation sources of energetic electrons and radiation. To date, however, acceleration distances have been severely limited by the lack of a controllable method for extending the propagation distance of the focused laser pulse. The ensuing short acceleration distance resulted in low-energy beams with 100 percent electron energy...

  16. Technical report on the accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Bex, L. [ed.

    1995-12-31

    GANIL operation and the technical studies performed in 1994 are described. The milestones for 1994 are: SISSI (Source d`Ions Secondaires a Supraconducteurs Intense) has been in operation and used for secondary beam production with four different primary beams. The 100 kV platform for beam injection in the CO1 has been in operation for production of metallic beams which demand is increasing. Finally the SPIRAL project (Systeme de Production d`Ions Radioactifs Acceleres en Ligne) is in progress. In late 1994 the civil work has started in view of the installation of the machine in the north part of the GANIL machine building. (K.A.). 48 refs.

  17. ACCELERATION GROWTH OF ICT MARKET

    Directory of Open Access Journals (Sweden)

    Drakulić Danica

    2007-06-01

    Full Text Available The wurk points to the importance of ICT (Information Communication Technologies, as one of the main trajectories by which advanced economies have come to the high dynamism and richness. How do the performsnces of these technological changes, determined mainly by ICT, exert influences on the economicgrowth or, in general, on production results at the aggregate, macroeconomic level. The U.S.A. supremacy in this field has faced challenges. It loses tempo, and the EU countries, after the multi-decade syndrome of technological catching up to U.S.A., go through faster into the future, giving an accelerating tone to the technological race.

  18. Flow accelerated organic coating degradation

    Science.gov (United States)

    Zhou, Qixin

    Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as

  19. AESS: Accelerated Exact Stochastic Simulation

    Science.gov (United States)

    Jenkins, David D.; Peterson, Gregory D.

    2011-12-01

    The Stochastic Simulation Algorithm (SSA) developed by Gillespie provides a powerful mechanism for exploring the behavior of chemical systems with small species populations or with important noise contributions. Gene circuit simulations for systems biology commonly employ the SSA method, as do ecological applications. This algorithm tends to be computationally expensive, so researchers seek an efficient implementation of SSA. In this program package, the Accelerated Exact Stochastic Simulation Algorithm (AESS) contains optimized implementations of Gillespie's SSA that improve the performance of individual simulation runs or ensembles of simulations used for sweeping parameters or to provide statistically significant results. Program summaryProgram title: AESS Catalogue identifier: AEJW_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJW_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: University of Tennessee copyright agreement No. of lines in distributed program, including test data, etc.: 10 861 No. of bytes in distributed program, including test data, etc.: 394 631 Distribution format: tar.gz Programming language: C for processors, CUDA for NVIDIA GPUs Computer: Developed and tested on various x86 computers and NVIDIA C1060 Tesla and GTX 480 Fermi GPUs. The system targets x86 workstations, optionally with multicore processors or NVIDIA GPUs as accelerators. Operating system: Tested under Ubuntu Linux OS and CentOS 5.5 Linux OS Classification: 3, 16.12 Nature of problem: Simulation of chemical systems, particularly with low species populations, can be accurately performed using Gillespie's method of stochastic simulation. Numerous variations on the original stochastic simulation algorithm have been developed, including approaches that produce results with statistics that exactly match the chemical master equation (CME) as well as other approaches that approximate the CME. Solution

  20. Decay of Quantum Accelerator Modes

    CERN Document Server

    Sheinman, M; Guarneri, I; Rebuzzini, L; Fishman, Shmuel; Guarneri, Italo; Rebuzzini, Laura; Sheinman, Michael

    2005-01-01

    Experimentally observable Quantum Accelerator Modes are used as a test case for the study of some general aspects of quantum decay from classical stable islands immersed in a chaotic sea. The modes are shown to correspond to metastable states, analogous to the Wannier-Stark resonances. Different regimes of tunneling, marked by different quantitative dependence of the lifetimes on 1/hbar, are identified, depending on the resolution of KAM substructures that is achieved on the scale of hbar. The theory of Resonance Assisted Tunneling introduced by Brodier, Schlagheck, and Ullmo [9], is revisited, and found to well describe decay whenever applicable.

  1. Gauge fields in accelerated frames

    CERN Document Server

    Lenz, F

    2008-01-01

    Quantized fields in accelerated frames (Rindler spaces) with emphasis on gauge fields are investigated. Important properties of the dynamics in Rindler spaces are shown to follow from the scale invariance of the corresponding Hamiltonians. Origin and consequences of this extraordinary property of Hamiltonians in Rindler spaces are elucidated. Characteristics of the Unruh radiation, the appearance of a photon condensate and the interaction energy of vector and scalar static charges are discussed and implications for Yang-Mills theories and QCD in Rindler spaces are indicated.

  2. Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Spentzouris, P.; /Fermilab; Cary, J.; /Tech-X, Boulder; McInnes, L.C.; /Argonne; Mori, W.; /UCLA; Ng, C.; /SLAC; Ng, E.; Ryne, R.; /LBL, Berkeley

    2011-11-14

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization

  3. FERMILAB ACCELERATOR R&D PROGRAM TOWARDS INTENSITY FRONTIER ACCELERATORS : STATUS AND PROGRESS

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir [Fermilab

    2016-11-15

    The 2014 P5 report indicated the accelerator-based neutrino and rare decay physics research as a centrepiece of the US domestic HEP program at Fermilab. Operation, upgrade and development of the accelerators for the near- term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss key elements of the accelerator physics and technology R&D program toward future multi-MW proton accelerators and present its status and progress. INTENSITY FRONTIER ACCELERATORS

  4. Novel Aspects of Direct Laser Acceleration of Relativistic Electrons

    CERN Document Server

    Arefiev, A V; Khudik, V N

    2015-01-01

    We examine the impact of several factors on electron acceleration by a laser pulse and the resulting electron energy gain. Specifically, we consider the role played by: 1) static longitudinal electric field; 2) static transverse electric field; 3) electron injection into the laser pulse; and 4) static longitudinal magnetic field. It is shown that all of these factors lead, under certain conditions, to a considerable electron energy gain from the laser pulse. In contrast with other mechanisms such as wakefield acceleration, the static electric fields in this case do not directly transfer substantial energy to the electron. Instead, they reduce the longitudinal dephasing between the electron and the laser beam, which then allows the electron to gain extra energy from the beam. The mechanisms discussed here are relevant to experiments with under-dense gas jets, as well as to experiments with solid-density targets involving an extended pre-plasma.

  5. Secondary electron emission from plasma processed accelerating cavity grade niobium

    Science.gov (United States)

    Basovic, Milos

    Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for higher energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were treated

  6. ACCELERATION OF TYPE II SPICULES IN THE SOLAR CHROMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Michael L., E-mail: mgoodman@wvhtf.org [Advanced Technologies Group, West Virginia High Technology Consortium Foundation, 1000 Galliher Drive, Fairmont, WV 26554 (United States)

    2012-10-01

    A 2.5D, time-dependent magnetohydrodynamic model is used to test the proposition that observed type II spicule velocities can be generated by a Lorentz force under chromospheric conditions. It is found that current densities localized on observed space and time scales of type II spicules and that generate maximum magnetic field strengths {<=}50 G can generate a Lorentz force that accelerates plasma to terminal velocities similar to those of type II spicules. Maximum vertical flow speeds are {approx}150-460 km s{sup -1}, horizontally localized within {approx}2.5-10 km from the vertical axis of the spicule, and comparable to slow solar wind speeds, suggesting that significant solar wind acceleration occurs in type II spicules. Horizontal speeds are {approx}20 times smaller than vertical speeds. Terminal velocity is reached {approx}100 s after acceleration begins. The increase in the mechanical and thermal energy of the plasma during acceleration is (2-3) Multiplication-Sign 10{sup 22} ergs. The radial component of the Lorentz force compresses the plasma during the acceleration process by factors as large as {approx}100. The Joule heating flux generated during this process is essentially due to proton Pedersen current dissipation and can be {approx}0.1-3.7 times the heating flux of {approx}10{sup 6} ergs cm{sup -2} s{sup -1} associated with middle-upper chromospheric emission. About 84%-94% of the magnetic energy that accelerates and heats the spicules is converted into bulk flow kinetic energy.

  7. Nonlinear Krylov acceleration of reacting flow codes

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S.; Rawat, R.; Smith, P.; Pernice, M. [Univ. of Utah, Salt Lake City, UT (United States)

    1996-12-31

    We are working on computational simulations of three-dimensional reactive flows in applications encompassing a broad range of chemical engineering problems. Examples of such processes are coal (pulverized and fluidized bed) and gas combustion, petroleum processing (cracking), and metallurgical operations such as smelting. These simulations involve an interplay of various physical and chemical factors such as fluid dynamics with turbulence, convective and radiative heat transfer, multiphase effects such as fluid-particle and particle-particle interactions, and chemical reaction. The governing equations resulting from modeling these processes are highly nonlinear and strongly coupled, thereby rendering their solution by traditional iterative methods (such as nonlinear line Gauss-Seidel methods) very difficult and sometimes impossible. Hence we are exploring the use of nonlinear Krylov techniques (such as CMRES and Bi-CGSTAB) to accelerate and stabilize the existing solver. This strategy allows us to take advantage of the problem-definition capabilities of the existing solver. The overall approach amounts to using the SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) method and its variants as nonlinear preconditioners for the nonlinear Krylov method. We have also adapted a backtracking approach for inexact Newton methods to damp the Newton step in the nonlinear Krylov method. This will be a report on work in progress. Preliminary results with nonlinear GMRES have been very encouraging: in many cases the number of line Gauss-Seidel sweeps has been reduced by about a factor of 5, and increased robustness of the underlying solver has also been observed.

  8. Normalization of Gravitational Acceleration Models

    Science.gov (United States)

    Eckman, Randy A.; Brown, Aaron J.; Adamo, Daniel R.

    2011-01-01

    Unlike the uniform density spherical shell approximations of Newton, the con- sequence of spaceflight in the real universe is that gravitational fields are sensitive to the nonsphericity of their generating central bodies. The gravitational potential of a nonspherical central body is typically resolved using spherical harmonic approximations. However, attempting to directly calculate the spherical harmonic approximations results in at least two singularities which must be removed in order to generalize the method and solve for any possible orbit, including polar orbits. Three unique algorithms have been developed to eliminate these singularities by Samuel Pines [1], Bill Lear [2], and Robert Gottlieb [3]. This paper documents the methodical normalization of two1 of the three known formulations for singularity-free gravitational acceleration (namely, the Lear [2] and Gottlieb [3] algorithms) and formulates a general method for defining normalization parameters used to generate normalized Legendre Polynomials and ALFs for any algorithm. A treatment of the conventional formulation of the gravitational potential and acceleration is also provided, in addition to a brief overview of the philosophical differences between the three known singularity-free algorithms.

  9. GPU Accelerated Vector Median Filter

    Science.gov (United States)

    Aras, Rifat; Shen, Yuzhong

    2011-01-01

    Noise reduction is an important step for most image processing tasks. For three channel color images, a widely used technique is vector median filter in which color values of pixels are treated as 3-component vectors. Vector median filters are computationally expensive; for a window size of n x n, each of the n(sup 2) vectors has to be compared with other n(sup 2) - 1 vectors in distances. General purpose computation on graphics processing units (GPUs) is the paradigm of utilizing high-performance many-core GPU architectures for computation tasks that are normally handled by CPUs. In this work. NVIDIA's Compute Unified Device Architecture (CUDA) paradigm is used to accelerate vector median filtering. which has to the best of our knowledge never been done before. The performance of GPU accelerated vector median filter is compared to that of the CPU and MPI-based versions for different image and window sizes, Initial findings of the study showed 100x improvement of performance of vector median filter implementation on GPUs over CPU implementations and further speed-up is expected after more extensive optimizations of the GPU algorithm .

  10. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  11. Winter therapy for the accelerators

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    Hundreds of people are hard at work during the year-end technical stop as all the accelerators are undergoing maintenance, renovation and upgrade operations in parallel.   The new beam absorber on its way to Point 2 before being lowered into the LHC tunnel for installation. The accelerator teams didn’t waste any time before starting their annual winter rejuvenation programme over the winter. At the end of November, as the LHC ion run was beginning, work got under way on the PS Booster, where operation had already stopped. On 14 December, once the whole complex had been shut down, the technical teams turned their attention to the other injectors and the LHC. The year-end technical stop (YETS) provides an opportunity to carry out maintenance work on equipment and repair any damage as well as to upgrade the machines for the upcoming runs. Numerous work projects are carried out simultaneously, so good coordination is crucial. Marzia Bernardini's team in the Enginee...

  12. Instructional Design for Accelerated Macrocognitive Expertise in the Baseball Workplace

    OpenAIRE

    Fadde, Peter J.

    2016-01-01

    The goal of accelerating expertise can leave researchers and trainers in human factors, naturalistic decision making, sport science, and expertise studies concerned about seemingly insufficient application of expert performance theories, findings and methods for training macrocognitive aspects of human performance. Video-occlusion methods perfected by sports expertise researchers have great instructional utility, in some cases offering an effective and inexpensive alternative to high-fidelity...

  13. Radiative damping in plasma-based accelerators

    Science.gov (United States)

    Kostyukov, I. Yu.; Nerush, E. N.; Litvak, A. G.

    2012-11-01

    The electrons accelerated in a plasma-based accelerator undergo betatron oscillations and emit synchrotron radiation. The energy loss to synchrotron radiation may seriously affect electron acceleration. The electron dynamics under combined influence of the constant accelerating force and the classical radiation reaction force is studied. It is shown that electron acceleration cannot be limited by radiation reaction. If initially the accelerating force was stronger than the radiation reaction force, then the electron acceleration is unlimited. Otherwise the electron is decelerated by radiative damping up to a certain instant of time and then accelerated without limits. It is shown that regardless of the initial conditions the infinite-time asymptotic behavior of an electron is governed by a self-similar solution providing that the radiative damping becomes exactly equal to 2/3 of the accelerating force. The relative energy spread induced by the radiative damping decreases with time in the infinite-time limit. The multistage schemes operating in the asymptotic acceleration regime when electron dynamics is determined by the radiation reaction are discussed.

  14. Conception design of helium ion FFAG accelerator with induction accelerating cavity

    Institute of Scientific and Technical Information of China (English)

    LUO Huan-Li; XU Yu-Cun; WANG Xiang-Qi; XU Hong-Liang

    2013-01-01

    In the recent decades of particle accelerator R&D area,the fixed field alternating gradient (FFAG) accelerator has become a highlight for some advantages of its higher beam intensity and lower cost,although there are still some technical challenges.In this paper,the FFAG accelerator is adopted to accelerate a helium ion beam on the one hand for the study of helium embrittlement on fusion reactor envelope material and on the other hand for promoting the conception research and design of the FFAG accelerator and exploring the possibility of developing high power FFAG accelerators.The conventional period focusing unit of the helium ion FFAG accelerator and threedimensional model of the large aperture combinatorial magnet by OPERA-TOSCA are given.For low energy and low revolution frequency,induction acceleration is proposed to replace conventional radio frequency (RF) acceleration for the helium ion FFAG accelerator,which avoids the potential breakdown of the acceleration field caused by the wake field and improves the acceleration repetition frequency to gain higher beam intensity.The main parameters and three-dimensional model of induction cavity are given.Two special constraint waveforms are proposed to refrain from particle accelerating time slip (AT) caused by accelerating voltage drop of flat top and energy deviation.The particle longitudinal motion in two waveforms is simulated.

  15. Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne; Mori, Warren; /UCLA; Ng, Cho; /SLAC; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2011-10-21

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  16. Acceleration of 3HE and heavy ions at interplanetary shocks

    Science.gov (United States)

    Desai, M. I.; Mason, G. M.; Dwyer, J. R.; Mazur, J. E.; Smith, C. W.; Koug, R. M.

    2001-08-01

    We have surveyed the 0.5-2.0 MeV nucleon-1 ion composition of 56 interplanetary shocks (IP) observed with the Ultra-Low-Energy Isotope Spectrometer (ULEIS) on board the Advanced Composition Explorer (ACE) from 1997 October 1 through 2000 November 30. Our results show the first ever measurement (25 cases) of 3 He ions being accelerated at IP shocks. The 3 He/4 He ratio at the 25 shocks exhibited a wide range of values between 0.00140.24; the ratios were enhanced between factors of ~3-600 over the solar wind value. During the survey period, the occurrence probability of 3 He-rich shocks increased with rising solar activity as measured in terms of the daily occurrence rates of sunspots and X-ray flares. The 3 He enhancements at IP shocks cannot be attributed to rigidity dependent acceleration of solar wind ions and are better explained if the shocks accelerate ions from multiple sources, one being remnant impulsive solar flare material enriched in 3 He ions. Our results also indicate that the contribution of impulsive flares to the seed population for IP shocks varies from event to event, and that the interplanetary medium is being replenished with impulsive material more frequently during periods of increased solar activity. 1. Introduction Enhancements in the intensities of energetic ions associated with transient interplanetary (IP) shocks have been observed routinely at 1 AU since the 1960's (e.g., Reames 1999). It is presently believed that the majority of such IP shocks are driven by fast coronal mass ejections or CMEs as they propagate through interplanetary space (e.g., Gosling 1993), and that the associated ion intensity enhancements are due to diffusive shock acceleration of solar wind ions (Lee 1983; Jones and Ellison 1991; Reames 1999). However, the putative solar wind origin of the IP-shock accelerated ions is based on composition measurements associated with a very limited number of individual IP shocks (Klecker et al. 1981; Hovestadt et al. 1982; Tan et

  17. Simulations of ion acceleration at non-relativistic shocks: ii) magnetic field amplification and particle diffusion

    CERN Document Server

    Caprioli, Damiano

    2014-01-01

    We use large hybrid (kinetic ions-fluid electrons) simulations to study ion acceleration and generation of magnetic turbulence due to the streaming of energetic particles that are self-consistently accelerated at non-relativistic shocks. When acceleration is efficient (at quasi-parallel shocks), we find that the magnetic field develops transverse components and is significantly amplified in the pre-shock medium. The total amplification factor is larger than 10 for shocks with Mach number $M=100$, and scales with the square root of $M$. We find that in the shock precursor the energy spectral density of excited magnetic turbulence is proportional to spectral energy distribution of accelerated particles at corresponding resonant momenta, in good agreement with the predictions of quasilinear theory of diffusive shock acceleration. We discuss the role of Bell's instability, which is predicted and found to grow faster than resonant instability in shocks with $M\\gtrsim 30$. Ahead of these strong shocks we distinguis...

  18. An Accelerator control middle layer using Matlab

    CERN Document Server

    Portmann, G J; Terebilo, Andrei

    2005-01-01

    Matlab is a matrix manipulation language originally developed to be a convenient language for using the LINPACK and EISPACK libraries. What makes Matlab so appealing for accelerator physics is the combination of a matrix oriented programming language, an active workspace for system variables, powerful graphics capability, built-in math libraries, and platform independence. A number of software toolboxes for accelerators have been written in Matlab – the Accelerator Toolbox (AT) for machine simulations, LOCO for accelerator calibration, Matlab Channel Access Toolbox (MCA) for EPICS connections, and the Middle Layer. This paper will describe the MiddleLayer software toolbox that resides between the high-level control applications and the low-level accelerator control system. This software was a collaborative effort between ALS and Spear but was written to easily port. Five accelerators presently use this software – Spear, ALS, CLS, and the X-ray and VUV rings at Brookhaven. The Middle Layer fu...

  19. Nonresonant Grain Acceleration in MHD Turbulence

    CERN Document Server

    Yan, Huirong

    2009-01-01

    We discuss a new type of dust acceleration mechanism that acts in a turbulent magnetized medium. The magnetohydrodynamic (MHD) turbulence can accelerate grains through resonant as well as nonresonant interactions. We show that the magnetic compression provides higher velocities for super-Alfv\\'enic turbulence and can accelerate an extended range of grains in warm media compared to gyroresonance. While fast modes dominate the acceleration for the large grains, slow modes can be important for sub-micron grains. We provide comprehensive discussion of all the possible grain acceleration mechanisms in interstellar medium. We show that supersonic velocities are attainable for Galactic dust grains. We discuss the consequence of the acceleration. The implications for extinction curve, grain alignment, chemical abundance, etc, are provided.

  20. CAS course on Plasma Wake Acceleration

    CERN Multimedia

    CERN Accelerator School

    2015-01-01

    The CERN Accelerator School (CAS) recently organised a specialised course on Plasma Wake Acceleration, held at CERN, Geneva, Switzerland, from 23 to 29 November 2014.    Following a number of introductory lectures on laser and plasma physics, as well as an overview of conventional accelerators and their limitations, the course covered a large number of aspects of plasma wake acceleration schemes: the creation of plasma by high power lasers or particle beams, a description of the plasma creation process through simulations and the characteristics of the accelerated particle beams, including results of the latest achievements. Lectures on beam diagnostics, the applications of plasma accelerated beams, and topical seminars completed the programme.  The course was very successful, with 109 students of 26 nationalities attending; most participants coming from European counties, but also from the US, Israel, India, South Korea, Russia and Ukraine. Feedback from the participants was...

  1. Likelihood Analysis of the Local Group Acceleration

    CERN Document Server

    Schmoldt, I M; Teodoro, L; Efstathiou, G P; Frenk, C S; Keeble, O; Maddox, S J; Oliver, S; Rowan-Robinson, M; Saunders, W J; Sutherland, W; Tadros, H; White, S D M

    1999-01-01

    We compute the acceleration on the Local Group using 11206 IRAS galaxies from the recently completed all-sky PSCz redshift survey. Measuring the acceleration vector in redshift space generates systematic uncertainties due to the redshift space distortions in the density field. We therefore assign galaxies to their real space positions by adopting a non-parametric model for the velocity field that solely relies on the linear gravitational instability and linear biasing hypotheses. Remaining systematic contributions to the measured acceleration vector are corrected for by using PSCz mock catalogues from N-body experiments. The resulting acceleration vector points approx. 15 degrees away from the CMB dipole apex, with a remarkable alignment between small and large scale contributions. A considerable fraction of the measured acceleration is generated within 40 h-1 Mpc with a non-negligible contribution from scales between 90 and 140 h-1 Mpc after which the acceleration amplitude seems to have converged. The local...

  2. Acceleration profiles in elite Australian soccer.

    Science.gov (United States)

    Varley, M C; Aughey, R J

    2013-01-01

    We quantified the acceleration and high-velocity running of elite Australian soccer players. We hypothesised that high-intensity activity would be underestimated when excluding acceleration during match analysis given its high metabolic demand and occurrence at low velocities. Player movements were observed from 29 players (forwards and central and wide defenders and midfielders) during domestic Australian competition using 5-Hz global positioning system. Effort occurrence were determined for high-velocity running, sprinting and maximal accelerations. The commencement and final velocity of maximal accelerations were also identified. Players undertook an 8~fold greater number of maximal accelerations than sprints per game (65±21 vs. 8±5). Of maximal accelerations ~98% commenced from a starting velocity lower than what would be considered high-velocity running while ~85% did not cross the high-velocity running threshold. The number of efforts performed in all categories were position dependent (Psprints compared to all other positions (Pdrills.

  3. The electromagnetic field in accelerated frames

    CERN Document Server

    Maluf, J W

    2011-01-01

    We develop a geometrical framework that allows to obtain the electromagnetic field quantities in accelerated frames. The frame of arbitrary accelerated observers in space-time is defined by a suitable set of tetrad fields, whose timelike components are adapted to the worldlines of a field of observers. We consider the Faraday tensor and Maxwell's equations as abstract tensor quantities in space-time, and make use of tetrad fields to project the electromagnetic field quantities in the accelerated frames. As an application, plane and spherical electromagnetic waves are projected in linearly accelerated frames in Minkowski space-time. We show that the amplitude, frequency and the wave vector of the plane wave in the accelerated frame vary with time, while the light speed remains constant. We also obtain the variation of the Poynting vector with time in the accelerated frame.

  4. Stephen Myers - More collaboration for accelerators

    CERN Multimedia

    2009-01-01

    Stephen Myers has been appointed Director of Accelerators and Technology. His highest priority is to get the LHC running this year, but beyond that he also has the difficult task of balancing resources between non-LHC physics, new projects and consolidation of the existing accelerators. Stephen Myers, previous head of the Accelerator and Beams (AB) Department, will now oversee all the accelerator and technology activities at CERN, including the Beams, Technology and Engineering departments, in the re-established position of Director of Accelerators and Technology. "There are several good reasons to have a single person responsible for the CERN accelerators and technology," said Myers. "Most importantly, this will allow closer collaboration between the three departments and provide the structure for possible redeployment of resources. There will, of course, be regular meetings between the heads of department and myself, and if proble...

  5. The Pulse Line Ion Accelerator Concept

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Richard J.

    2006-02-15

    The Pulse Line Ion Accelerator concept was motivated by the desire for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. A pulse power driver applied at one end of a helical pulse line creates a traveling wave pulse that accelerates and axially confines the heavy ion beam pulse. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/meter acceleration gradients. The concept might be described crudely as an ''air core'' induction linac where the PFN is integrated into the beam line so the accelerating voltage pulse can move along with the ions to get voltage multiplication.

  6. Elements of a dielectric laser accelerator

    CERN Document Server

    McNeur, Joshua; Schönenberger, Norbert; Leedle, Kenneth J; Deng, Huiyang; Ceballos, Andrew; Hoogland, Heinar; Ruehl, Axel; Hartl, Ingmar; Solgaard, Olav; Harris, James S; Byer, Robert L; Hommelhoff, Peter

    2016-01-01

    The widespread use of high energy particle beams in basic research, medicine and coherent X-ray generation coupled with the large size of modern radio frequency (RF) accelerator devices and facilities has motivated a strong need for alternative accelerators operating in regimes outside of RF. Working at optical frequencies, dielectric laser accelerators (DLAs) - transparent laser-driven nanoscale dielectric structures whose near fields can synchronously accelerate charged particles - have demonstrated high-gradient acceleration with a variety of laser wavelengths, materials, and electron beam parameters, potentially enabling miniaturized accelerators and table-top coherent x-ray sources. To realize a useful (i.e. scalable) DLA, crucial developments have remained: concatenation of components including sustained phase synchronicity to reach arbitrary final energies as well as deflection and focusing elements to keep the beam well collimated along the design axis. Here, all of these elements are demonstrated wit...

  7. Magnetic acceleration of ultra-relativistic GRB and AGN jets

    CERN Document Server

    Maxim, Barkov

    2008-01-01

    We present numerical simulations of cold, axisymmetric, magnetically driven relativistic outflows. The outflows are initially sub-Alfv\\'enic and Poynting flux-dominated, with total--to--rest-mass energy flux ratio up to $\\mu \\sim 620$. To study the magnetic acceleration of jets we simulate flows confined within a funnel with rigid wall of prescribed shape, which we take to be $z\\propto r^a$ (in cylindrical coordinates, with $a$ ranging from 1 to 2). This allows us to eliminate the numerical dissipative effects induced by a free boundary with an ambient medium. We find that in all cases they converge to a steady state characterized by a spatially extended acceleration region. For the jet solutions the acceleration process is very efficient - on the outermost scale of the simulation more than half of the Poynting flux has been converted into kinetic energy flux, and the terminal Lorentz factor approached its maximum possible value ($\\Gamma_\\infty \\simeq \\mu$). The acceleration is accompanied by the collimation ...

  8. On the efficient acceleration of clouds in active galactic nuclei

    CERN Document Server

    Waters, Tim

    2016-01-01

    In the broad line region of AGN, acceleration occurs naturally when a cloud condenses out of the hot confining medium due to the increase in line opacity as the cloud cools. However, acceleration by radiation pressure is not very efficient when the flux is time-independent, unless the flow is one-dimensional. Here we explore how acceleration is affected by a time-varying flux, as AGN are known to be highly variable. If the period of flux oscillations is longer than the thermal timescale, we expect the gas to cool during the low flux state, and therefore line opacity should quickly increase. The cloud will receive a small kick due to the increased radiation force. We perform hydrodynamical simulations using Athena to confirm this effect and quantify its importance. We find that despite the flow becoming turbulent in 2D due to hydrodynamic instabilities, a 20% modulation of the flux leads to a net increase in acceleration --- by more than a factor of 2 --- in both 1D and 2D. We show that this is sufficient to p...

  9. High Voltage Operation of Helical Pulseline Structures for Ion Acceleration

    CERN Document Server

    Waldron, William; Reginato, Lou

    2005-01-01

    The basic concept for the acceleration of heavy ions using a helical pulseline requires the launching of a high voltage traveling wave with a waveform determined by the beam transport physics in order to maintain stability and acceleration.* This waveform is applied to the front of the helix, creating over the region of the ion bunch a constant axial acceleration electric field that travels down the line in synchronism with the ions. Several methods of driving the helix have been considered. Presently, the best method of generating the waveform and also maintaining the high voltage integrity appears to be a transformer primary loosely coupled to the front of the helix, generating the desired waveform and achieving a voltage step-up from primary to secondary (the helix). This can reduce the drive voltage that must be brought into the helix enclosure through the feedthroughs by factors of 5 or more. The accelerating gradient is limited by the voltage holding of the vacuum insulator, and the material and helix g...

  10. Sliding response of gravity dams including vertical seismic accelerations

    Institute of Scientific and Technical Information of China (English)

    Constantin Christopoulos; Pierre Léger; André Filiatrault

    2003-01-01

    Seismic safety assessment of gravity dams has become a major concern in many regions of the world while the effects of vertical seismic accelerations on the response of structures remain poorly understood. This paper first investigates the effect of including vertical accelerations in the sliding response analysis of gravity dams subjected to a range of historical ground motion records separated in two groups according to their source-to-site distance. Analyses showed that the incidence of vertical accelerations on the sliding response of gravity dams is significantly higher for near-source records than for farsource records. The pseudo-static 30% load combination rule, commonly used in practice to account for the non-simultaneous occurrence of the peak horizontal and vertical accelerations, yielded good approximations of the minimum safety factors against sliding computed from time-history analyses. A method for empirically estimating the vertical response spectra based on horizontal spectra, accounting for the difference in frequency content and amplitudes between the two components is investigated. Results from analyses using spectrum compatible horizontal and vertical synthetic records also approximated well the sliding response of a gravity dam subjected to series of simultaneous horizontal and vertical historical earthquake records.

  11. Accelerating VASP electronic structure calculations using graphic processing units

    KAUST Repository

    Hacene, Mohamed

    2012-08-20

    We present a way to improve the performance of the electronic structure Vienna Ab initio Simulation Package (VASP) program. We show that high-performance computers equipped with graphics processing units (GPUs) as accelerators may reduce drastically the computation time when offloading these sections to the graphic chips. The procedure consists of (i) profiling the performance of the code to isolate the time-consuming parts, (ii) rewriting these so that the algorithms become better-suited for the chosen graphic accelerator, and (iii) optimizing memory traffic between the host computer and the GPU accelerator. We chose to accelerate VASP with NVIDIA GPU using CUDA. We compare the GPU and original versions of VASP by evaluating the Davidson and RMM-DIIS algorithms on chemical systems of up to 1100 atoms. In these tests, the total time is reduced by a factor between 3 and 8 when running on n (CPU core + GPU) compared to n CPU cores only, without any accuracy loss. © 2012 Wiley Periodicals, Inc.

  12. The unequivocal evidence of hadron acceleration in Tycho's Supernova Remnant

    CERN Document Server

    Morlino, G

    2011-01-01

    We apply the non-linear diffusive shock acceleration theory in order to describe the properties of SN 1572 (G120.1+1.4, hereafter simply Tycho). By analyzing its multi-wavelength spectrum, we show how Tycho's forward shock is accelerating protons up to ~500 TeV, channelling into cosmic rays more than 10% of its kinetic energy. Our model allows us to take into account self-consistently the dynamical reaction of the accelerated particles, the generation of magnetic fields in the shock proximity and the dynamical reaction of the magnetic field as well. We find that the streaming instability induced by cosmic rays is consistent with all the observational evidences indicating a very efficient magnetic field amplification (up to ~300 uG, in particular the radio and X-ray morphology of the remnant. In such a strong magnetic field, the velocity of the scattering centers in the upstream may be enhanced and make accelerated particles feel an effective compression factor lower than 4, in turn leading to an energy spectr...

  13. Superconducting accelerating structures for very low velocity ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Shepard, K.W.; Ostroumov, P.N.; Fuerst, J.D.; Waldschmidt, G.; /Argonne; Gonin, I.V.; /Fermilab

    2008-01-01

    This paper presents designs for four types of very-low-velocity superconducting accelerating cavity capable of providing several MV of accelerating potential per cavity, and suitable for particle velocities in the range 0.006 < v/c < 0.06. Superconducting TEM-class cavities have been widely applied to CW acceleration of ion beams. SC linacs can be formed as an array of independently-phased cavities, enabling a variable velocity profile to maximize the output energy for each of a number of different ion species. Several laboratories in the US and Europe are planning exotic beam facilities based on SC linacs. The cavity designs presented here are intended for the front-end of such linacs, particularly for the post-acceleration of rare isotopes of low charge state. Several types of SC cavities have been developed recently to cover particle velocities above 0.06c. Superconducting four-gap quarter-wave resonators for velocities 0.008 < {beta} = v/c < 0.05 were developed about two decades ago and have been successfully operated at the ATLAS SC linac at Argonne National Laboratory. Since that time, progress in simulation tools, cavity fabrication and processing have increased SC cavity gradients by a factor of 3-4. This paper applies these tools to optimize the design of a four-gap quarter-wave resonator for exotic beam facilities and other low-velocity applications.

  14. GPUs as Storage System Accelerators

    CERN Document Server

    Al-Kiswany, Samer; Ripeanu, Matei

    2012-01-01

    Massively multicore processors, such as Graphics Processing Units (GPUs), provide, at a comparable price, a one order of magnitude higher peak performance than traditional CPUs. This drop in the cost of computation, as any order-of-magnitude drop in the cost per unit of performance for a class of system components, triggers the opportunity to redesign systems and to explore new ways to engineer them to recalibrate the cost-to-performance relation. This project explores the feasibility of harnessing GPUs' computational power to improve the performance, reliability, or security of distributed storage systems. In this context, we present the design of a storage system prototype that uses GPU offloading to accelerate a number of computationally intensive primitives based on hashing, and introduce techniques to efficiently leverage the processing power of GPUs. We evaluate the performance of this prototype under two configurations: as a content addressable storage system that facilitates online similarity detectio...

  15. FEL-accelerator related diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Jordan; David Douglas; Stephen V. Benson; Pavel Evtuschenko

    2007-08-02

    Free Electron Lasers (FEL) present a unique set of beam parameters to the diagnostics suite. The FEL requires characterization of the full six dimensional phase space of the electron beam at the wiggler and accurate alignment of the electron beam to the optical mode of the laser. In addition to the FEL requirements on the diagnostics suite, the Jefferson Lab FEL is operated as an Energy Recovered Linac (ERL) which imposes additional requirements on the diagnostics. The ERL aspect of the Jefferson Lab FEL requires that diagnostics operate over a unique dynamic range and operate with simultaneous transport of the accelerated and energy recovered beams. This talk will present how these challenges are addressed at the Jefferson Lab FEL.

  16. Accelerated Characterization of Polymer Properties

    Energy Technology Data Exchange (ETDEWEB)

    R. Wroczynski; l. Brewer; D. Buckley; M. Burrell; R. Potyrailo

    2003-07-30

    This report describes the efforts to develop a suite of microanalysis techniques that can rapidly measure a variety of polymer properties of industrial importance, including thermal, photo-oxidative, and color stability; as well as ductility, viscosity, and mechanical and antistatic properties. Additional goals of the project were to direct the development of these techniques toward simultaneous measurements of multiple polymer samples of small size in real time using non-destructive and/or parallel or rapid sequential measurements, to develop microcompounding techniques for preparing polymers with additives, and to demonstrate that samples prepared in the microcompounder could be analyzed directly or used in rapid off-line measurements. These enabling technologies are the crucial precursors to the development of high-throughput screening (HTS) methodologies for the polymer additives industry whereby the rate of development of new additives and polymer formulations can be greatly accelerated.

  17. Testing general relativity on accelerators

    CERN Document Server

    Kalaydzhyan, Tigran

    2015-01-01

    Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyse experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable -- maximal energy of the scattered photons -- would experience a significant shift in the Earth's gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of res...

  18. Development project of small accelerator

    CERN Document Server

    Yamada, S

    2002-01-01

    The object of this project is demonstration of a small proton and heavy ion synchrotron and a small hard X-ray photon radiation source by using new technology and application of them to therapy, diagnosis, material science and life science. In this paper, a part of small proton and heavy ion synchrotron is discussed. Nine organizations joined in this project. There are four development themes such as optimization of laser-ion 100 TW class source target, beam storage and cooling device, small synchrotron ring and FFAG accelerator. Outline and contents of development of them are explained. This project is planning to generate a few MeV/u carbon ions in fully ionized states by impact of laser with about 100 TW output. 3 T maximum bending magnetic field using normal conduction AC magnet will be actualized for synchrotron with 200 MeV proton beam. (S.Y.)

  19. Accelerating the life of transistors

    Science.gov (United States)

    Haochun, Qi; Changzhi, Lü; Xiaoling, Zhang; Xuesong, Xie

    2013-06-01

    Choosing small and medium power switching transistors of the NPN type in a 3DK set as the study object, the test of accelerating life is conducted in constant temperature and humidity, and then the data are statistically analyzed with software developed by ourselves. According to degradations of such sensitive parameters as the reverse leakage current of transistors, the lifetime order of transistors is about more than 104 at 100 °C and 100% relative humidity (RH) conditions. By corrosion fracture of transistor outer leads and other failure modes, with the failure truncated testing, the average lifetime rank of transistors in different distributions is extrapolated about 103. Failure mechanism analyses of degradation of electrical parameters, outer lead fracture and other reasons that affect transistor lifetime are conducted. The findings show that the impact of external stress of outer leads on transistor reliability is more serious than that of parameter degradation.

  20. Accelerating the life of transistors

    Institute of Scientific and Technical Information of China (English)

    Qi Haochun; Lü Changzhi; Zhang Xiaoling; Xie Xuesong

    2013-01-01

    Choosing small and medium power switching transistors of the NPN type in a 3DK set as the study object,the test of accelerating life is conducted in constant temperature and humidity,and then the data are statistically analyzed with software developed by ourselves.According to degradations of such sensitive parameters as the reverse leakage current of transistors,the lifetime order of transistors is about more than 104 at 100 ℃ and 100% relative humidity (RH) conditions.By corrosion fracture of transistor outer leads and other failure modes,with the failure truncated testing,the average lifetime rank of transistors in different distributions is extrapolated about 103.Failure mechanism analyses of degradation of electrical parameters,outer lead fracture and other reasons that affect transistor lifetime are conducted.The findings show that the impact of external stress of outer leads on transistor reliability is more serious than that of parameter degradation.

  1. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU TaJung

    2001-01-01

    @@ The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  2. Neuroscience and Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Palmblad, M N; Buchholz, B A; Hillegonds, D J; Vogel, J S

    2004-08-02

    Accelerator mass spectrometry (AMS) is a mass spectrometric method for quantifying rare isotopes. It has had great impact in geochronology and archaeology and is now being applied in biomedicine. AMS measures radioisotopes such as {sup 3}H, {sup 14}C, {sup 26}Al, {sup 36}Cl and {sup 41}Ca, with zepto- or attomole sensitivity and high precision and throughput, enabling safe human pharmacokinetic studies involving: microgram doses, agents having low bioavailability, or toxicology studies where administered doses must be kept low (<1 {micro}g/kg). It is used to study long-term pharmacokinetics, to identify biomolecular interactions, to determine chronic and low-dose effects or molecular targets of neurotoxic substances, to quantify transport across the blood-brain barrier and to resolve molecular turnover rates in the human brain on the timescale of decades. We will here review how AMS is applied in neurotoxicology and neuroscience.

  3. Interactive troubleshooting guide for accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Legg, R.; Dunham, B.; Higgins, S.; Kazimi, R.; Kehne, D.; Oren, T.

    1997-12-01

    Modern accelerators face the challenge of supporting increased machine complexity and higher levels of utilization while relying on downsized maintenance and support groups. To improve system availability, reduce reliance on system experts and provide a systematic approach to problem solving, an interactive troubleshooting guide has been implemented for the CEBAF injector at Jefferson lab. This guide, which uses a tree structure with appropriate hypertext links, traces problems from a set of symptoms, through a series of diagnostic tests, to a specific corrective action. This guide is used in conjunction with an active parameter monitoring system that is part of the EPICS control system tool kit. The monitoring system generates operator alarms when injector RF or magnet parameters fall outside pre-set windows. Operators receive immediate feedback when injector components vary from their standard values and the troubleshooting guide provides a systematic means to identify and ultimately correct the problem.

  4. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU; TaJung

    2001-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.  ……

  5. Theoretical Aspects of Cosmic Acceleration

    CERN Document Server

    Trodden, Mark

    2016-01-01

    Efforts to understand and map the possible explanations for the late time acceleration of the universe have led to a broad range of suggestions, ranging from the cosmological constant and straightforward dark energy, to exotically coupled models, to infrared modifications of General Relativity. If we are to uncover which, if any, of these approaches might provide a serious answer to the problem, it is crucial to understand the constraints that theoretical consistency places on the models, and on the regimes in which they make predictions. In this talk, delivered as an invited plenary lecture at the Dark Side of the Universe conference in Kyoto, Japan, I briefly describe some modern attempts to carry out this program and some of the more interesting ideas that have emerged. As an example, I use the Galileon model, discussing how the Vainshtein mechanism occurs, and how a number of these theoretical problems arise around such backgrounds.

  6. INDIRECT ACCELERATED ADAPTIVE FUZZY CONTROLLER

    Institute of Scientific and Technical Information of China (English)

    ZHU Liye; FANG Yuan; ZHANG Weidong

    2008-01-01

    According to a type of normal nonlinear system, an indirect adaptive fuzzy (IAF) controller has been applied to those systems where no accurate mathematical models of the systems under control are available. To satisfy with system performance, an indirect accelerated adaptive fuzzy (IAAF) controller is proposed, and its general form is presented. The general form IAAF controller ensures necessary control criteria and system's global stability using Lyapunov Theorem. It has been proved that the close-loop system error converges to a small neighborhood of equilibrium point. The optimal IAAF controller is derived to guarantee the process's shortest settling time. Simulation results indicate the IAAF controller make the system more stable, accurate, and fast.

  7. Extinction Events Can Accelerate Evolution

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific......Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate...... evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending...

  8. Extinction events can accelerate evolution.

    Directory of Open Access Journals (Sweden)

    Joel Lehman

    Full Text Available Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term.

  9. Building bridges … and accelerators

    CERN Multimedia

    2009-01-01

    Lyn Evans, the LHC project leader, was awarded an honorary doctorate from the University of Geneva (UNIGE) to celebrate his role not just in building accelerators, but also in building bridges between nations. He was one of four notables honoured at the event on Friday 5 June, coinciding with the University’s 450th Anniversary. Lyn Evans arriving at the ceremony with Archbishop Desmond Tutu. "It was a big surprise when I found out I’d been nominated," recounts Evans, "but it was an even bigger surprise to find out with whom I’d been nominated". At the ceremony Evans was awarded the honorary doctorate along with three others: Archbishop Desmond Tutu, who was acclaimed for his fight against apartheid in South Africa, Mary Robinson, first woman president of Ireland and former United Nations’ high commissioner of human rights, and Pascal Lamy, Director-General of the World Trade Organization. The award ceremony, known as the �...

  10. Extinction Events Can Accelerate Evolution

    Science.gov (United States)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term. PMID:26266804

  11. Report on accelerated corrosion studies.

    Energy Technology Data Exchange (ETDEWEB)

    Mowry, Curtis Dale; Glass, Sarah Jill; Sorensen, Neil Robert

    2011-03-01

    Sandia National Laboratories (SNL) conducted accelerated atmospheric corrosion testing for the U.S. Consumer Product Safety Commission (CPSC) to help further the understanding of the development of corrosion products on conductor materials in household electrical components exposed to environmental conditions representative of homes constructed with problem drywall. The conditions of the accelerated testing were chosen to produce corrosion product growth that would be consistent with long-term exposure to environments containing humidity and parts per billion (ppb) levels of hydrogen sulfide (H{sub 2}S) that are thought to have been the source of corrosion in electrical components from affected homes. This report documents the test set-up, monitoring of electrical performance of powered electrical components during the exposure, and the materials characterization conducted on wires, screws, and contact plates from selected electrical components. No degradation in electrical performance (measured via voltage drop) was measured during the course of the 8-week exposure, which was approximately equivalent to 40 years of exposure in a light industrial environment. Analyses show that corrosion products consisting of various phases of copper sulfide, copper sulfate, and copper oxide are found on exposed surfaces of the conductor materials including wires, screws, and contact plates. The morphology and the thickness of the corrosion products showed a range of character. In some of the copper wires that were observed, corrosion product had flaked or spalled off the surface, exposing fresh metal to the reaction with the contaminant gasses; however, there was no significant change in the wire cross-sectional area.

  12. Materials considerations in accelerator targets

    Science.gov (United States)

    Peacock, H. B.; Iyer, N. C.; Louthan, M. R.

    1995-09-01

    Future nuclear materials production and/or the burn-up of long lived radioisotopes may be accomplished through the capture of spallation produced neutrons in accelerators. Aluminum clad-lead and/or lead alloys has been proposed as a spallation target. Aluminum was the cladding choice because of the low neutron absorption cross section, fast radioactivity decay, high thermal conductivity, and excellent fabricability. Metallic lead and lead oxide powders were considered for the target core with the fabrication options being casting or powder metallurgy (PM). Scoping tests to evaluate gravity casting, squeeze casting, and casting and swaging processes showed that, based on fabricability and heat transfer considerations, squeeze casting was the preferred option for manufacture of targets with initial core cladding contact. Thousands of aluminum clad aluminum-lithium alloy core targets and control rods for tritium production have been fabricated by coextrusion processes and successfully irradiated in the SRS reactors. Tritium retention in, and release from, the coextruded product was modeled from experimental and operational data. The model assumed that tritium atoms, formed by the 6Li(n,a)3He reaction, were produced in solid solution in the Al-Li alloy. Because of the low solubility of hydrogen isotopes in aluminum alloys, the irradiated Al-Li rapidly became supersaturated in tritium. Newly produced tritium atoms were trapped by lithium atoms to form a lithium tritide. The effective tritium pressure required for trap or tritide stability was the equilibrium decomposition pressure of tritium over a lithium tritide-aluminum mixture. The temperature dependence of tritium release was determined by the permeability of the cladding to tritium and the local equilibrium at the trap sites. The model can be used to calculate tritium release from aluminum clad, aluminum-lithium alloy targets during postulated accelerator operational and accident conditions. This paper describes

  13. Accelerating cleanup: Paths to closure

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-06-01

    This report describes the status of Environmental Management`s (EM`s) cleanup program and a direction forward to complete achievement of the 2006 vision. Achieving the 2006 vision results in significant benefits related to accomplishing EM program objectives. As DOE sites accelerate cleanup activities, risks to public health, the environment, and worker safety and health are all reduced. Finding more efficient ways to conduct work can result in making compliance with applicable environmental requirements easier to achieve. Finally, as cleanup activities at sites are completed, the EM program can focus attention and resources on the small number of sites with more complex cleanup challenges. Chapter 1 describes the process by which this report has been developed and what it hopes to accomplish, its relationship to the EM decision-making process, and a general background of the EM mission and program. Chapter 2 describes how the site-by-site projections were constructed, and summarizes, for each of DOE`s 11 Operations/Field Offices, the projected costs and schedules for completing the cleanup mission. Chapter 3 presents summaries of the detailed cleanup projections from three of the 11 Operations/Field Offices: Rocky Flats (Colorado), Richland (Washington), and Savannah River (South Carolina). The remaining eight Operations/Field Office summaries are in Appendix E. Chapter 4 reviews the cost drivers, budgetary constraints, and performance enhancements underlying the detailed analysis of the 353 projects that comprise EM`s accelerated cleanup and closure effort. Chapter 5 describes a management system to support the EM program. Chapter 6 provides responses to the general comments received on the February draft of this document.

  14. Dielectric laser acceleration of non-relativistic electrons at a photonic structure

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, John

    2013-08-29

    Stanford. The potential of dielectric laser accelerators lies in the larger attainable acceleration gradients resulting in a more compact design as well as a lower cost of these devices compared with conventional accelerator facilities. This size reduction by potentially a factor of 100 is owed to the two orders of magnitude larger damage threshold of dielectric materials as compared to metals. We present an outlook towards the design of an envisioned large-scale dielectric laser accelerator and its possible application in future compact free electron lasers.

  15. Fixed-Field Alternating-Gradient Accelerators

    CERN Document Server

    Sheehy, S L

    2016-01-01

    These notes provide an overview of Fixed-Field Alternating-Gradient (FFAG) accelerators for medical applications. We begin with a review of the basic principles of this type of accelerator, including the scaling and non-scaling types, highlighting beam dynamics issues that are of relevance to hadron ac- celerators. The potential of FFAG accelerators in the field of hadron therapy is discussed in detail, including an overview of existing medical FFAG designs. The options for FFAG treatment gantries are also considered.

  16. Unifying physics of accelerators, lasers and plasma

    CERN Document Server

    Seryi, Andrei

    2015-01-01

    Unifying Physics of Accelerators, Lasers and Plasma introduces the physics of accelerators, lasers and plasma in tandem with the industrial methodology of inventiveness, a technique that teaches that similar problems and solutions appear again and again in seemingly dissimilar disciplines. This unique approach builds bridges and enhances connections between the three aforementioned areas of physics that are essential for developing the next generation of accelerators.

  17. Kinematics of transition during human accelerated sprinting

    Directory of Open Access Journals (Sweden)

    Ryu Nagahara

    2014-07-01

    Full Text Available This study investigated kinematics of human accelerated sprinting through 50 m and examined whether there is transition and changes in acceleration strategies during the entire acceleration phase. Twelve male sprinters performed a 60-m sprint, during which step-to-step kinematics were captured using 60 infrared cameras. To detect the transition during the acceleration phase, the mean height of the whole-body centre of gravity (CG during the support phase was adopted as a measure. Detection methods found two transitions during the entire acceleration phase of maximal sprinting, and the acceleration phase could thus be divided into initial, middle, and final sections. Discriminable kinematic changes were found when the sprinters crossed the detected first transition—the foot contacting the ground in front of the CG, the knee-joint starting to flex during the support phase, terminating an increase in step frequency—and second transition—the termination of changes in body postures and the start of a slight decrease in the intensity of hip-joint movements, thus validating the employed methods. In each acceleration section, different contributions of lower-extremity segments to increase in the CG forward velocity—thigh and shank for the initial section, thigh, shank, and foot for the middle section, shank and foot for the final section—were verified, establishing different acceleration strategies during the entire acceleration phase. In conclusion, there are presumably two transitions during human maximal accelerated sprinting that divide the entire acceleration phase into three sections, and different acceleration strategies represented by the contributions of the segments for running speed are employed.

  18. Cyclinacs: Fast-Cycling Accelerators for Hadrontherapy

    OpenAIRE

    Amaldi, U.; Braccini, S.; Citterio, A; Crandall, K.; Crescenti, M.; Dominietto, M.; Giuliacci, A.; Magrin, G.; Mellace, C.; Pearce, P; Pitta', G.; Rosso, E.; Weiss, M.; Zennaro, R.

    2009-01-01

    We propose an innovative fast-cycling accelerator complex conceived and designed to exploit at best the properties of accelerated ion beams for hadrontherapy. A cyclinac is composed by a cyclotron, which can be used also for other valuable medical and research purposes, followed by a high gradient linear accelerator capable to produce ion beams optimized for the irradiation of solid tumours with the most modern techniques. The properties of cyclinacs together with design studies for protons a...

  19. Control of robot dynamics using acceleration control

    Science.gov (United States)

    Workman, G. L.; Prateru, S.; Li, W.; Hinman, Elaine

    1992-01-01

    Acceleration control of robotic devices can provide improvements to many space-based operations using flexible manipulators and to ground-based operations requiring better precision and efficiency than current industrial robots can provide. This paper reports on a preliminary study of acceleration measurement on robotic motion during parabolic flights on the NASA KC-135 and a parallel study of accelerations with and without gravity arising from computer simulated motions using TREETOPS software.

  20. A Novel Permanent Magnetic Angular Acceleration Sensor

    OpenAIRE

    Hao Zhao; Hao Feng

    2015-01-01

    Angular acceleration is an important parameter for status monitoring and fault diagnosis of rotary machinery. Therefore, we developed a novel permanent magnetic angular acceleration sensor, which is without rotation angle limitations and could directly measure the instantaneous angular acceleration of the rotating system. The sensor rotor only needs to be coaxially connected with the rotating system, which enables convenient sensor installation. For the cup structure of the sensor rotor, it h...