SN Test Research Articles

Computation of the Strain Induced Critical Current Reduction in the 16 T Nb3Sn Test Facility Dipole

A test facility dipole is being developed at LBNL, targeting a 16 T field in a 144 mm wide aperture. The magnet uses a block design, with two double-pancake coils. In order to minimize motion under the large Lorentz forces, the coils are preloaded against a thick aluminum shell and iron yoke using bladder and key technology. It is then crucial to verify that the performance of the magnet is not degraded due to strain induced on the Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn conductor during assembly, cool-down and powering. The critical current of extracted strands was measured in a varying background magnetic field and as a function of the applied longitudinal strain. Finite element analysis was used to extract the strain state inside the superconducting strands during magnet assembly and operation. This strain was then compared to the measurements to evaluate potential reversible and irreversible effects on the magnet performances. The results suggest that the magnet can reach 16 T with sufficient margin, with no irreversible degradation in the high field region.

Segmenting Time Series via Self-Normalisation

AbstractWe propose a novel and unified framework for change-point estimation in multivariate time series. The proposed method is fully non-parametric, robust to temporal dependence and avoids the demanding consistent estimation of long-run variance. One salient and distinct feature of the proposed method is its versatility, where it allows change-point detection for a broad class of parameters (such as mean, variance, correlation and quantile) in a unified fashion. At the core of our method, we couple the self-normalisation- (SN) based tests with a novel nested local-window segmentation algorithm, which seems new in the growing literature of change-point analysis. Due to the presence of an inconsistent long-run variance estimator in the SN test, non-standard theoretical arguments are further developed to derive the consistency and convergence rate of the proposed SN-based change-point detection method. Extensive numerical experiments and relevant real data analysis are conducted to illustrate the effectiveness and broad applicability of our proposed method in comparison with state-of-the-art approaches in the literature.

Specific humoral immunity in mink infected with the Aleutian disease virus (AMDV) and vaccinated against distemper

The Aleutian mink disease (AD) is one of the most serious threats to modern mink breeding. In farms where AD is endemic, a significant effect on breeding and reproductive effects is caused by permanent AMDV infection. The aim of this study was investigating the influence of subclinical infection of AMDV on the functional immune status and on the state of postvaccinal immunity against mink distemper. The analyses involved 30 brown mink females aged 12 weeks and allocated into an experimental group (group I) and control group (group II), with 15 animals in each. The minks from group I originated from the farm with an endemic form of Aleutian disease. The control minks from group II originated from the AMDV-uninfected farm. The dynamics of the growth of specific antibodies was examined after vaccination of the minks from both groups against distemper. Serum levels were determined in both groups with a seroneutralisation assay (SN). Obtaining positive values in the SN test in both groups of animals confirmed the induction of a specific immune response. There were significant differences in the magnitude of the positive SN assay values between the minks from group I and group II at all days of determination. The significantly lower SN values noted in the group minks with subclinical course of AMDV reveal that Aleutian disease can cause a suppressive effect on humoral response after vaccination.

Momentum injection by clustered supernovae: testing subgrid feedback prescriptions

ABSTRACT Using a 1D Lagrangian code specifically designed to assess the impact of multiple, time-resolved supernovae (SNe) from a single-star cluster on the surrounding medium, we test three commonly used feedback recipes: delayed cooling (e.g. used in the gasoline-2 code), momentum-energy injection (a resolution-dependent transition between momentum-dominated feedback and energy-dominated feedback used, e.g. in the fire-2 code), and simultaneous energy injection (e.g. used in the EAGLE simulations). Our work provides an intermediary test for these recipes: we analyse a setting that is more complex than the simplified scenarios for which many were designed, but one more controlled than a full galactic simulation. In particular, we test how well these models reproduce the enhanced momentum efficiency seen for an 11 SN cluster simulated at high resolution (0.6 pc; a factor of 12 enhancement relative to the isolated SN case) when these subgrid recipes are implemented in low resolution (20 pc) runs. We find that: (1) the delayed cooling model performs well – resulting in 9 times the momentum efficiency of the fiducial isolated SN value – when SNe are clustered and 1051 erg are injected per SN, while clearly overpredicting the momentum efficiency in the single SN test case; (2) the momentum-energy model always achieves good results, with a factor of 5 boost in momentum efficiency; and (3) injecting the energy from all SNe simultaneously does little to prevent overcooling and greatly underproduces the momentum deposited by clustered SNe, resulting in a factor of 3 decrease in momentum efficiency on the average.

Protection of human influenza vaccines against a reassortant swine influenza virus of pandemic H1N1 origin using a pig model

Since the pandemic H1N1 emergence in 2009 (pdmH1N1), many reassortant pdmH1N1 viruses emerged and found circulating in the pig population worldwide. Currently, commercial human subunit vaccines are used commonly to prevent the influenza symptom based on the WHO recommendation. In case of current reassortant swine influenza viruses transmitting from pigs to humans, the efficacy of current human influenza vaccines is of interest. In this study, influenza A negative pigs were vaccinated with selected commercial human subunit vaccines and challenged with rH3N2. All sera were tested with both HI and SN assays using four representative viruses from the surveillance data in 2012 (enH1N1, pdmH1N1, rH1N2 and rH3N2). The results showed no significant differences in clinical signs and macroscopic and microscopic findings among groups. However, all pig sera from vaccinated groups had protective HI titers to the enH1N1, pdmH1N1 and rH1N2 at 21DPV onward and had protective SN titers only to pdmH1N1and rH1N2 at 21DPV onward. SN test results appeared more specific than those of HI tests. All tested sera had no cross-reactivity against the rH3N2. Both studied human subunit vaccines failed to protect and to stop viral shedding with no evidence of serological reaction against rH3N2. SIV surveillance is essential for monitoring a novel SIV emergence potentially for zoonosis.

A comparison of two modified stationarity tests. A Monte Carlo study

To specify an econometric model with time series data, it is important to determine the order of integration of the variables in the model. In this paper, using a complete set of Monte Carlo experiments, we compare the behaviour of two stationarity tests, the Xiao test (Sn) and the KPSS (Kwiatkowski, Phillips, Schmidt and Shin) test, using an alternative estimator of the long-run variance to those used in the original version of the tests, to recommend which one to use in practice. First, we compare the small sample properties of the original Sn test with those of its modified version. We conclude that this modified version has a better size versus power trade-off than the original test. So, second, we compare the finite sample properties of the modified Sn and the modified KPSS. Since the modified KPSS exhibits higher power and size, we conduct a second experiment determining the critical value of each test, in such a way that the power of both tests coincides at 0.5, and then we examine their size for some local-to-unity values. The results show that, in most cases, the performance of the modified KPSS test dominates that of the modified Sn test.

Serological and virological detection of canine herpesvirus-1 in adult dogs with and without reproductive disorders

Canine herpesvirus 1 (CaHV-1) is known to cause reproductive disorders in adult dogs and neonatal mortality in puppies. The seroprevalence of CaHV-1 has not been documented in Italy. Sera from 865 dogs were screened for CaHV-1 using a serum neutralization assay (SN). All CaHV-1 positive sera and 100 CaHV-1 negative sera were also tested using an in-house immunofluorescence (IF) test. Thirteen bitches with reproductive disorders and three bitches with no history of reproductive diseases were also examined clinically so that lesions associated with CaHV-1 and CaHV-1 DNA could be identified using PCR analysis of vaginal swabs.An overall seroprevalence of 14.6% was observed using SN, and 18.6% using IF. The correlation between SN and IF was moderate. The SN assay demonstrated a greater sensitivity than IF, with a few exceptions. None of the vaginal swabs tested positive for CaHV-1 DNA. The differences in the seropositivity rates between SN and IF were not statistically significant (P = 0.16). Using the SN test as the reference standard, the sensitivity and specificity of IF were 29% and 95%, respectively. These results suggest that CaHV-1 is common in canine populations and could pose a threat to neonatal survival and canine fertility in breeding kennels in Italy. Vaccination of breeding bitches should be recommended if there is a history of reproductive disorders.

Autochthonous tick-borne encephalitis virus (TBEV) - seropositive cattle in Belgium: a risk-based targeted serological survey

Tick-borne encephalitis virus (TBEV) is the most important arthropod-borne virus in Europe. The Western subtype of this pathogenic neurotropic flavivirus is carried by Ixodes ricinus. Tick-borne encephalitis has become a considerable public risk in several European countries, with currently 3000 hospitalized cases per year. The risk of TBEV-introduction into Belgium remains high and the presence of infected wildlife in Belgium is suspected. Domestic animals such as dogs or cattle can serve as excellent sentinels for TBEV-surveillance in order to install an early warning surveillance component for this emerging zoonotic disease of public importance. In a targeted, risk-based and cross-sectional sampling design, serological screening was performed on Belgian cattle (n = 650), selected from the 2010 Belgian national cattle surveillance serum bank. The three most Eastern provinces of Belgium, which are geographically situated closest to known and/or recently emerging TBEV-endemic, were targeted. These areas are also currently known as endemic for Lyme disease (Borrelia burgdorferi), another disease transmitted by the same tick. Bovine sera were tested at the TBEV Belgian National Reference Centre at the WIV-ISP, by gold standard TBEV seroneutralisation test, based on the rapid fluorescent focus inhibition test (RFFIT) protocol. Using a conservative >1/15 cut-off titer for SN test, 17 bovines were seropositive and six had borderline results (1/10 < titer < 1/15). The accuracy of the RFFIT-SNT was confirmed in a mouse inoculation test and by West Nile virus and Rabies virus serology. There was a positive correlation between the neutralizing antibody titer, determined by SN, and the median survival time in mice inoculated intranasally with a mix of virus and serum. Lesions consistent of viral encephalitis were demonstrated in histopathology. The overall bovine TBEV-seroprevalence in the targeted area was estimated between 2.6 and 4.3% and freedom could no longer be substantiated. Bovines with borderline results were often located close to confirmed seropositive animals. The geographical locations roughly coincided with the known Belgian hot spots for Lyme disease. This risk-based cross-sectional serological survey in cattle, obtained through one health cooperation confirms the presence of infected foci in Belgium for the first time. Given the relevance of TBEV for the food chain through consumption of unpasteurized milk and cheese and through its considerable public burden in other European countries, further surveillance in cattle, other sentinels, ticks and humans at risk is recommended to further determine the location and size of endemic foci and the risk for public health.

Attempt to Detect Evidence for Tick-Borne Encephalitis Virus in Ticks and Mammalian Wildlife in the Netherlands

To investigate if tick-borne encephalitis virus (TBEV) is present in mammalian wildlife species or ticks in The Netherlands, serum samples and ticks were tested for TBEV antibodies and TBEV RNA, respectively. Serum samples were collected from wild boar (666), deer (13), fox (399), and rodents (90), and were tested for TBEV antibodies, using ELISA, and SN test or HI test. Over a period of 4 years, a total of 906 ticks was collected from seven regions in The Netherlands. In four different regions, this was done on a monthly basis and during four consecutive summers. All ticks were tested for TBEV RNA by RT-PCR. TBEV antibody was detected by ELISA in two (0.5%) sera of foxes and 49 (7%) sera of wild boar, but not confirmed by HI or SNT. TBEV RNA was not detected in any of 906 ticks. It was concluded that there is no real evidence for a TBEV reservoir in ticks or wildlife in The Netherlands.

Effect of virus-specific antibodies on attachment, internalization and infection of porcine reproductive and respiratory syndrome virus in primary macrophages

Porcine reproductive and respiratory syndrome virus (PRRSV) induces respiratory distress in young pigs and reproductive failure in sows. In PRRSV infected pigs, virus persists for several weeks to several months. Although IPMA antibodies are detected from 7 days post inoculation (pi), virus neutralizing (VN) antibodies are commonly detected starting from 3 weeks pi with an SN test on Marc-145 cells. Since infection of Marc-145 cells is quite different compared to infection of macrophages, the in vivo target cell, the role of these VN antibodies in in vivo protection is questionable. In our study, we demonstrated that antibodies from pigs early in infection with PRRSV Lelystad virus (14 days pi) showed no neutralization in the SN test on Marc-145 cells, but partially reduced Lelystad virus infection of porcine alveolar macrophages. At 72 days pi, VN antibodies were detected by the SN test on Marc-145 cells, and these protected macrophages completely against Lelystad virus infection. In contrast, these VN antibodies only partially reduced porcine alveolar macrophage infection of a Belgian PRRSV isolate (homologous virus), and had no effect on infection of porcine alveolar macrophages with the American type VR-2332 strain (heterologous virus). Confocal analysis of Lelystad virus attachment and internalization in macrophages showed that antibodies blocked infection through both a reduction in virus attachment, and a reduction of PRRSV internalization. Western immunoblotting analysis revealed that sera from 14 days pi, which showed no neutralization in the SN test on Marc-145 cells but partially reduced Lelystad virus infection of macrophages, predominantly recognized the Lelystad virus N protein, and reacted faintly with the M envelope protein. Sera from 72 days pi, with VN antibodies that blocked infection of Marc-145 cells and PAM, reacted with the N protein and the two major envelope proteins M and GP5. Using the Belgian PRRSV isolate 94V360 an identical but less intense reactivity profile was obtained. VN sera also recognized the VR-2332 N and M protein, but not the GP5 protein.

Effects of Sn on the oxidation and oxide characteristics of Zr alloys in water and a LiOH solution

To investigate the Sn effects on the oxidation and oxide characteristics of Zr-xSn (x=02.0wt%) binary alloys, autoclave tests were performed in pure water and LiOH solutions containing 2.2 and 70 ppm Li. Corrosion behavior of the Zr-xSn binary alloys was found to be highly dependent on the Sn content and test environment. Corrosion resistance of the Zr-xSn alloys decreased with increasing Sn content in pure water, but increased with increasing Sn content in the LiOH solution. In pure water, a high Sn content accelerated transformation of the oxide microstructure from a columnar grain to an equiaxed grain and the oxide crystal structure from tetragonal to monoclinic. However, this trend was not maintained in the LiOH solution because Li-penetration into the oxide played a more important role than Sn in the transformation of the oxide properties. It is suggested that high Sn content tends to retard Li-penetration into the oxide in LiOH solution.

Wetting characteristics of Pb-free solder alloys and PWB finishes

For a successful transition to Pb-free manufacturing in electronics assembly, it is critical to understand the behavior of Pb-free solders (in bulk and paste form) and their interaction with the Pb-free printed wiring board (PWB) finishes. This paper presents the results obtained from solder paste spread tests and wetting balance experiments with several Pb-free solder alloys and Pb-free PWB finishes. The solder alloys studied were Sn3.4Ag4.8Bi, Sn4.0Ag0.5Cu, Sn3.5Ag and Sn0.7Cu. Eutectic Sn37Pb was used as a reference. The PWB surface finishes were Sn, NiAu, Ag and OSP. Wetting balance experiments were conducted in air while the spread tests were performed in air and nitrogen to understand the effect of reflow atmosphere on the spreading. Surface analysis techniques such as Nomarski phase contrast microscopy, Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-received PWB finishes. Sequential electrochemical reduction analysis (SERA) was also performed on the as-received PWB test coupons and on the Sn test coupons after multiple reflow cycles. The effect of multiple reflow cycles on the wetting performance, spreading and the surface composition of the PWB finishes was studied.

A comparative study on the immune response of sheep to foot and mouth disease virus vaccine type Asia-1 prepared with different inactivants and adjuvants

Foot and mouth disease virus type Asia-1 was inactivated either with formaldehyde or binaryethylenimine (BEI). Inactivated vaccines were prepared incorporating aluminium hydroxide gel or mineral oil as an adjuvant. The antibody response to the adult sheep was studied by ELISA and SN test for a period of 6 months. There was no difference in the antibody response between vaccines inactivated with formaldehyde or BEI. Whereas significant difference in the antibody response was observed between gel and oil vaccines. The high titres of antibody stimulated by oil vaccines persisted longer than those of gel vaccines within the period of study.

Humoral Immunity of Neonatal Swine after FMD Vaccination

The possible effect on pig protection after vaccination pregnant sows and their piglets against FMD at various age was examined using the SN test. Three experiments were conducted with three sow in each (8-9 piglets each). In the first experiment sows were not vaccinated but their piglets were vaccinated on 10th, 20th and 60th day of age. In second experiment sows were vaccinated at the end of rest period and in the middle of pregnancy. Pigs from one sow were vaccinated on 10th, from second sow on 20th and from the third sow on the 60th day of age. Pigs which were vaccinated on the 10th and 20th day of age were revaccinated on the 60th day of age. In third experiment sows were vaccinated at the end of the rest period and in the middle of pregnancy. Their piglets were not vaccinated. The conclusion may be drawn that if the epidemiological situation requires, systemic vaccination of all pigs then, on large farms (where pig production is planned) all sows should be vaccinated at the end of the rest period (first vaccination) and on the 55th-60th day of pregnancy. The next vaccination should be done in the middle of the next pregnancy. A vaccination program of piglets, according to our results, should depend on the vaccination program used for their dams.

Manufacture of the Westinghouse forced flow Nb&amp;lt;inf&amp;gt;3&amp;lt;/inf&amp;gt;Sn test coil for the large coil program

Manufacturing of the Westinghouse forced flow Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn coil for the Oak Ridge National Laboratory Large Coil Program (LCP) is complete. The coil is installed in the Large Coil Test Facility (LCTF) at Oak Ridge National Laboratory and is being tested. The coil design concept is briefly presented to better understand the complexities of the manufacturing processes. This paper describes step-by-step procedures for the Westinghouse LCP coil manufacture. The facilities required and the training of the shop personnel are also discussed. The quality requirements and the quality procedures at each step of fabrication are described. Some of the serious problems which arose during manufacturing are pointed out along with the fixes to these problems. Some of the important development tasks needed for manufacture of this coil are listed. In every case, the completion of these tasks resulted in process modification prior to actual commitment to manufacture. This paper also highlights the major design and manufacturing advantages of the Westinghouse LCP coil. The goal of the Westinghouse LCP coil is to demonstrate the potential of Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn for large scale applications to either high field or high current density magnets.

Serological studies of mucosal disease virus in England and Wales

A survey of the cattle population in England and Wales showed that about 62 per cent of animals had neutralising (SN) antibody to BVD-MD virus in their serum. Fewer seropositive individuals were detected by immunodiffusion (53 per cent), and complement fixation (CF) tests (34 per cent). The prevalence of antibody was not affected by herd size, but some variation was found between various regions of the country, and the proportion of animals seropositive rose markedly with age. The immunodiffusion test was a specific but relatively insensitive method of detecting antibody compared with the SN test. The data suggest that the CF test may detect a different, short-lived antibody. For diagnostic serology, the SN test was superior to the other methods. No antibody to the virus was detected in human or equine sera but about 7.3 per cent of sheep sampled had serum antibody to the virus in the immunodiffusion test.

Microtiter tests for detecting antibody in bovine serum to parainfluenza 3 virus, infectious bovine rhinotracheitis virus, and bovine virus diarrhea virus.

Microneutralization tests for detection of antibody in bovine serum to three bovine viruses are described. The Madin-Darby bovine kidney cell line was used with parainfluenza 3 virus (PI 3), whereas serially cultivated bovine embryonic kidney cells were used for infectious bovine rhinotracheitis virus and bovine virus diarrhea virus. Comparison of micro-hemagglutination-inhibition (HI) with micro-serum-neutralization (SN) tests for PI 3 showed the SN test to be more sensitive, more specific, and therefore more useful than the HI test for detecting antibody. Although the effect of trypsin-periodate treatment of serum was to reduce the HI titer of numerous sera by a twofold dilution, sufficient evidence could not be found to indicate that nonspecific HI inhibitors to PI 3 are present in bovine sera.

Microtiter Tests for Detecting Antibody in Bovine Serum to Parainfluenza 3 Virus, Infectious Bovine Rhinotracheitis Virus, and Bovine Virus Diarrhea Virus

Microneutralization tests for detection of antibody in bovine serum to three bovine viruses are described. The Madin-Darby bovine kidney cell line was used with parainfluenza 3 virus (PI 3), whereas serially cultivated bovine embryonic kidney cells were used for infectious bovine rhinotracheitis virus and bovine virus diarrhea virus. Comparison of micro-hemagglutination-inhibition (HI) with micro-serum-neutralization (SN) tests for PI 3 showed the SN test to be more sensitive, more specific, and therefore more useful than the HI test for detecting antibody. Although the effect of trypsin-periodate treatment of serum was to reduce the HI titer of numerous sera by a twofold dilution, sufficient evidence could not be found to indicate that nonspecific HI inhibitors to PI 3 are present in bovine sera.