A SOURCE OF PROPELLER EXCITED BROADBAND VIBRATION ON A HIGH-SPEED TWIN SCREW SHIP

The cause of the severe propeller excited broadband vibration on a twin screw ship’s stern was investigated in a cavitation tunnel using conventional modelling methods. At first sight the results did not indicate anything untoward about the stern and propeller designs tested, apart from some unusual cavitation patterns in the propellers’ slipstreams. The fluctuating pressure levels on the model hull varied considerably depending on the propeller designs and loading conditions used in the tests, but these did not provide an explanation for the vibration on the ship. Some unusual patterns in the relative levels of the harmonic pressures on the stern were noticed in addition to the presence of a large cavitation disturbance in a propeller trailing vortex that was captured in a single frame of a video recording. This latter observation led to a plausible explanation for the broadband vibration on the ship’s stern.

Three days in December: Jewish human rights between the United Nations and the middle east in 1948

The twin birth of the UN Universal Declaration of Human Rights and the UN Genocide Convention in 1948 have received enormous scholarly attention in recent years. Yet historians have largely ignored how these legal projects intersected with that year’s war in Israel/Palestine. In this article, I push these two stories back into a single frame by examining the year-long efforts of one early human rights organization, the World Jewish Congress, to advance rights-claims on behalf of Middle Eastern Jewish communities imperiled by the regional repercussions of the war. The WJC’s record of activities affords us a direct window into contemporaneous activist understandings of the ties between the Holocaust and the Nakba, human rights and genocide, and international law and politics. More broadly, it reveals the intrinsic limits of early human rights advocacy in an emerging global system exclusively structured around nation states.

Digital processing of shadowgraph images taking into account the diffraction of light at a shock front

The aim of the study is to determine the shock wave position in experimental shadowgraph images and to evaluate the accuracy by digital image processing. The experimental images were obtained with the shock tube with a rectangular channel. The shadowgraph optical system formed a parallel light beam. It passed through the plane-parallel quartz glasses of the shock tube test section. The process synchronization system at the facility allows registering the shadowgraph images of unsteady flows with shock waves with a high-speed camera or with a single frame camera. The obtained spatial intensity profiles were used to determine the coordinates of gas-dynamic discontinuities at different stages of the flow evolution. shadowgraph patterns were analysed taking into account diffraction at the shock front in case of a laser light source.

Deep-Learning Super-Resolution Microscopy Reveals Nanometer-Scale Intracellular Dynamics at the Millisecond Temporal Resolution

Single-molecule localization microscopy (SMLM) can be used to resolve subcellular structures and achieve a tenfold improvement in spatial resolution compared to that obtained by conventional fluorescence microscopy. However, the separation of single-molecule fluorescence events in thousands of frames dramatically increases the image acquisition time and phototoxicity, impeding the observation of instantaneous intracellular dynamics. Based on deep learning networks, we develop a single-frame super-resolution microscopy (SFSRM) approach that reconstructs a super-resolution image from a single frame of a diffraction-limited image to support live-cell super-resolution imaging at a ∼20 nm spatial resolution and a temporal resolution of up to 10 ms over thousands of time points. We demonstrate that our SFSRM method enables the visualization of the dynamics of vesicle transport at a millisecond temporal resolution in the dense and vibrant microtubule network in live cells. Moreover, the well-trained network model can be used with different live-cell imaging systems, such as confocal and light-sheet microscopes, making super-resolution microscopy accessible to nonexperts.

THE GWAC DATA PROCESSING AND MANAGEMENT SYSTEM

GWAC will have been built an integrated FOV of 5,000 degree2 and have already built 1,800 square degree2. The limit magnitude of a 10-second exposure image in the moonless night is 16R. In each observation night, GWAC produces about 0.7TB of raw data, and the data processing pipeline generates millions of single frame alerts. We describe the GWAC Data Processing and Management System (GPMS), including hardware architecture, database, detection-filtering-validation of transient candidates, data archiving, and user interfaces for the check of transient and the monitor of the system. GPMS combines general technology and software in astronomy and computer field, and use some advanced technologies such as deep learning. Practical results show that GPMS can fully meet the scientific data processing requirement of GWAC. It can online accomplish the detection, filtering and validation of millions of transient candidates, and feedback the final results to the astronomer in real-time. During the observation from October of 2018 to December of 2019, we have already found 102 transients.