1,790 research outputs found
Hyper-velocity impact test and simulation of a double-wall shield concept for the Wide Field Monitor aboard LOFT
The space mission LOFT (Large Observatory For X-ray Timing) was selected in
2011 by ESA as one of the candidates for the M3 launch opportunity. LOFT is
equipped with two instruments, the Large Area Detector (LAD) and the Wide Field
Monitor (WFM), based on Silicon Drift Detectors (SDDs). In orbit, they would be
exposed to hyper-velocity impacts by environmental dust particles, which might
alter the surface properties of the SDDs. In order to assess the risk posed by
these events, we performed simulations in ESABASE2 and laboratory tests. Tests
on SDD prototypes aimed at verifying to what extent the structural damages
produced by impacts affect the SDD functionality have been performed at the Van
de Graaff dust accelerator at the Max Planck Institute for Nuclear Physics
(MPIK) in Heidelberg. For the WFM, where we expect a rate of risky impacts
notably higher than for the LAD, we designed, simulated and successfully tested
at the plasma accelerator at the Technical University in Munich (TUM) a
double-wall shielding configuration based on thin foils of Kapton and
Polypropylene. In this paper we summarize all the assessment, focussing on the
experimental test campaign at TUM.Comment: Proc. SPIE 9144, Space Telescopes and Instrumentation 2014:
Ultraviolet to Gamma Ray, 91446
Социально ориентированные программы, KIDS SAVE LIVES (Дети спасают жизни), World Restart a Heart (Перезапусти сердце) и другие кампании для повышения выживаемости при внебольничной остановке сердца
Sudden out-of-hospital cardiac arrest (OHCA) is the third leading cause of death in industrialized nations.While educating lay bystanders in CPR is clearly the most important way to increase survival in this third leading cause of death and the community programs are helpful, it is less easy to reach the entire population if programs are not obligatory. Therefore experts see the need for obligatory inclusion of CPR education in schools. And this is exactly our clear expectation to all politicians involved in health care and school politics worldwide. Until this is reality in all countries, we invite everyone to help to convince the responsible politicians and to take part in campaigns like KIDS SAVE LIVES and WRAH.Внезапная внебольничная остановка сердца (ВОС) — третья по частоте причина смерти в развитых странах.Обучение основам СЛР лиц без медицинского образования — наиболее важная стратегия повышения выживаемости при остановке сердца. Программы, включающие такое обучение, весьма эффективны, однако полного охвата населения достичь очень трудно вследствие их необязательного статуса. В связи с этим, по мнению экспертов, СЛР необходимо ввести в школьную программу в качестве обязательного предмета. Именно этого мы ждем от политиков, ответственных за систему здравоохранения и образование, во всех странах. Пока наша цель не достигнута, мы призываем всех помочь нам убедить ответственных лиц и принять участие в таких кампаниях, как KIDS SAVE LIVES и World Restart a Heart
Elastic constants of nematic liquid crystals of uniaxial symmetry
We study in detail the influence of molecular interactions on the Frank
elastic constants of uniaxial nematic liquid crystals composed of molecules of
cylindrical symmetry. A brief summary of the status of theoretical development
for the elastic constants of nematics is presented. Considering a pair
potential having both repulsive and attractive parts numerical calculations are
reported for three systems MBBA, PAA and 8OCB. For these systems the
length-to-width ratio is estimated from the experimentally proposed
structure of the molecules. The repulsive interaction is represented by a
repulsion between hard ellipsoids of revolution (HER) and the attractive
potential is represented by the quadrupole and dispersion interactions. From
the numerical results we observe that in the density range of nematics the
contribution of the quadrupole and dispersion interactions are small as
compared to the repulsive HER interaction. The inclusion of attractive
interaction reduces the values of elastic constants ratios. The temperature
variation of elastic constants ratios are reported and compared with the
experimental values. A reasonably good agreement between theory and experiment
is observed
Analysis of the use of tenon joints in the design of wood products
У роботі розглядаються та перевіряються шипові з’єднання при проектуванні та будуванні дерев’яної меблі. Проводиться функціональний аналіз та аналіз напружень з’єднань у Autodesk Inventor.The paper considers and checks tenon joints in the design and construction of
wooden furniture. The functional and stress analysis of joints in Autodesk Inventor is carried
out.
Lowering the energy threshold in COSINE-100 dark matter searches
COSINE-100 is a dark matter detection experiment that uses NaI(Tl) crystal
detectors operating at the Yangyang underground laboratory in Korea since
September 2016. Its main goal is to test the annual modulation observed by the
DAMA/LIBRA experiment with the same target medium. Recently DAMA/LIBRA has
released data with an energy threshold lowered to 1 keV, and the persistent
annual modulation behavior is still observed at 9.5. By lowering the
energy threshold for electron recoils to 1 keV, COSINE-100 annual modulation
results can be compared to those of DAMA/LIBRA in a model-independent way.
Additionally, the event selection methods provide an access to a few to sub-GeV
dark matter particles using constant rate studies. In this article, we discuss
the COSINE-100 event selection algorithm, its validation, and efficiencies near
the threshold
Calcium Homeostasis in Myogenic Differentiation Factor 1 (MyoD)-Transformed, Virally-Transduced, Skin-Derived Equine Myotubes
Dysfunctional skeletal muscle calcium homeostasis plays a central role in the pathophysiology of several human and animal skeletal muscle disorders, in particular, genetic disorders associated with ryanodine receptor 1 (RYR1) mutations, such as malignant hyperthermia, central core disease, multiminicore disease and certain centronuclear myopathies. In addition, aberrant skeletal muscle calcium handling is believed to play a pivotal role in the highly prevalent disorder of Thoroughbred racehorses, known as Recurrent Exertional Rhabdomyolysis. Traditionally, such defects were studied in human and equine subjects by examining the contractile responses of biopsied muscle strips exposed to caffeine, a potent RYR1 agonist. However, this test is not widely available and, due to its invasive nature, is potentially less suitable for valuable animals in training or in the human paediatric setting. Furthermore, increasingly, RYR1 gene polymorphisms (of unknown pathogenicity and significance) are being identified through next generation sequencing projects. Consequently, we have investigated a less invasive test that can be used to study calcium homeostasis in cultured, skin-derived fibroblasts that are converted to the muscle lineage by viral transduction with a MyoD (myogenic differentiation 1) transgene. Similar models have been utilised to examine calcium homeostasis in human patient cells, however, to date, there has been no detailed assessment of the cells’ calcium homeostasis, and in particular, the responses to agonists and antagonists of RYR1. Here we describe experiments conducted to assess calcium handling of the cells and examine responses to treatment with dantrolene, a drug commonly used for prophylaxis of recurrent exertional rhabdomyolysis in horses and malignant hyperthermia in humans
- …