An accelerator facility for intermediate energy proton irradiation and testing of nuclear materials

The bulk irradiation of materials with 10-30 MeV protons promises to advance the study of radiation damage for fission and fusion power plants. Intermediate energy proton beams can now be dedicated to materials irradiation within university-scale laboratories. This paper describes the first such facility, with an Ionetix ION-12SC cyclotron producing 12 MeV proton beams. Samples are mm-scale tensile specimens with thicknesses up to 300 um, mounted to a cooled beam target with control over temperature. A specialized tensile tester for radioactive specimens at high temperature (500+ {\deg}C) and/or vacuum represents the conditions in fission and fusion systems, while a digital image correlation system remotely measures strain. Overall, the facility provides university-scale irradiation and testing capability with intermediate energy protons to complement traditional in-core fission reactor and micro-scale ion irradiation. This facility demonstrates that bulk proton irradiation is a scalable and effective approach for nuclear materials research, down-selection, and qualification.Comment: Submitted to NIM B journa

Neuraminidase Inhibitor Susceptibility of Influenza Viruses Circulating in Bulgaria during the Last Four Consecutive Epidemic Seasons (2011/12 to 2014/15)

Emergence of resistant influenza virus progeny to currently approved antiviral drugs determines the need for antiviral susceptibility monitoring. The aim of the present study is to analyze neuraminidase inhibitor susceptibility of influenza viruses circulating in Bulgaria during the 2011/2012, 2012/2013, 2013/2014 and 2014/2015 flu seasons. A phenotypic fluorescence-based assay with MUNANA substrate was conducted with 93 influenza A(H1N1)pdm09, A(H3N2) and type B isolates. Screening of 352 influenza A(H1N1)pdm09 viruses was carried out using a Real Time RT-PCR discrimination assay for detection of the H275Y oseltamivir resistance point mutation. Phenotypic (IC50) evidence for resistance or reduced susceptibility to neuraminidase inhibitors was not found for any of the influenza A(H1N1)pdm09, A(H3N2) and type B viruses screened. Only one (0,3%) influenza A(H1N1)pdm09 virus carrying the H275Y substitution was detected. Real Time RT-PCR assay could be applied to screen large numbers of clinical A(H1N1)pdm09 influenza virus positive samples for oseltamivir resistance. The present study highlights the importance of continued influenza antiviral susceptibility monitoring in clinical specimens

Структура, непроницаемость и долговечность цементного бетона

The paper presents the main hypotheses of frost destruction of cement concrete. The influence of cyclic temperature changes and the effect of static and dynamic (shock) loads on concrete on changes in the structure and strength of concreteis considered. The paper provides results of comparative tests of frost resistance of concrete containing a porous additive and a plasticizer, which contribute to an increase in the density and impermeability of its structure. It has been shown experimentally that the introduction of air-entraining additives with an additional effect of hydrophobization is productive from the standpoint of ensuring frost resistance of concrete of relatively low classes (up to C30/37), compressive strength up to 50 MPa and water absorption by mass more than 4.0 %. It is advisable to increase the frost resistance of concrete with greater impermeability and strength by increasing these indicators, in particular, due to the maximum decrease in the initial water content and high-quality compaction. This conclusion is experimentally confirmed by the data presented in the paper, since the “mechanism” of frost destruction of cement concrete is multifactorial, and the growth of its density (impermeability) and strength provide a higher ability to resist “force” effects associated with repeated alternating deformations of concrete, as well as the action of external loads, accumulation of fatigue phenomena, hydrodynamics of liquid filtration under the influence of changing temperature fields, etc. A comparative assessment of concrete frost resistance has been carried out using standardized and patented techniques containing a porous (air-entraining) additive, as well as plasticizing and mineral additives of amorphous micro-silica, introduced into concrete in order to increase its density, impermeability and strength and on this basis – increasing frost resistance. Experimental data are presented, reflecting the relationship and patterns of decrease in frost resistance of concrete subjected to the simultaneous action of static (for compression – different levels from the corresponding indicator of concrete strength) and shock, concentratedly applied dynamic loads. The regularity of the relationship between the accelerated frost destruction of concrete and the action of mechanical loads that cause cracking in its structure has been confirmed.. В статье представлены основные гипотезы морозной деструкции цементного бетона. Рассмотрено влияние циклических изменений температуры и воздействия на бетон статической и динамической (ударной) нагрузок на изменения в структуре и прочности бетона. Приведены результаты сравнительных испытаний морозостойкости бетона, содержащего поризующую добавку и пластификатор, способствующий повышению плотности и непроницаемости его структуры. Экспериментально показано, что введение воздухововлекающих добавок, обладающих дополнительным эффектом гидрофобизации, продуктивно с позиций обеспечения морозостойкости бетонов относительно низких классов (до С30/37), прочностью на сжатие до 50 МПа и водопоглощением по массе более 4,0 %. Морозостойкость бетона большей непроницаемости и прочности целесообразно повышать, наращивая эти показатели, в частности, за счет максимального уменьшения начального водосодержания и качественного уплотнения. Этот вывод экспериментально подтверждают приведенные в статье данные, так как «механизм» морозной деструкции цементного бетона многофакторный, а рост его плотности (непроницаемости) и прочности обеспечивает более высокую способность сопротивляться силовым воздействиям, связанным с многократно повторяющимися знакопеременными деформациями бетона, а также с действием внешних нагрузок, накоплением усталостных явлений, гидродинамики фильтрации жидкости под влиянием изменяющихся температурных полей и проч. С использованием стандартизированных и авторских методик проведена сравнительная оценка морозостойкости бетона, содержащего поризующую (воздухововлекающую) добавку, а также пластифицирующие и минеральную добавки аморфного микрокремнезема, вводимые в бетон с целью увеличения его плотности, непроницаемости и прочности, а на этой основе – повышения морозостойкости. Приведены экспериментальные данные, отражающие взаимосвязь и закономерности снижения морозостойкости бетона, подверженного одновременному воздействию статической (на сжатие – разного уровня от соответствующего показателя прочности бетона) и ударной, сосредоточенно приложенной динамической нагрузок. Подтверждена закономерность взаимосвязи ускоренной морозной деструкции бетона с действием механических нагрузок, вызывающих трещинообразование в его структуре

Taxing the Informal Economy: The Current State of Knowledge and Agendas for Future Research

This paper reviews the literature on taxation of the informal economy, taking stock of key debates and drawing attention to recent innovations. Conventionally, the debate on whether to tax has frequently focused on the limited revenue potential, high cost of collection, and potentially adverse impact on small firms. Recent arguments have increasingly emphasised the more indirect benefits of informal taxation in relation to economic growth, broader tax compliance, and governance. More research is needed, we argue, into the relevant costs and benefits for all, including quasi-voluntary compliance, political and administrative incentives for reform, and citizen-state bargaining over taxation

Global disparities in SARS-CoV-2 genomic surveillance

Genomic sequencing is essential to track the evolution and spread of SARS-CoV-2, optimize molecular tests, treatments, vaccines, and guide public health responses. To investigate the global SARS-CoV-2 genomic surveillance, we used sequences shared via GISAID to estimate the impact of sequencing intensity and turnaround times on variant detection in 189 countries. In the first two years of the pandemic, 78% of high-income countries sequenced >0.5% of their COVID-19 cases, while 42% of low- and middle-income countries reached that mark. Around 25% of the genomes from high income countries were submitted within 21 days, a pattern observed in 5% of the genomes from low- and middle-income countries. We found that sequencing around 0.5% of the cases, with a turnaround time <21 days, could provide a benchmark for SARS-CoV-2 genomic surveillance. Socioeconomic inequalities undermine the global pandemic preparedness, and efforts must be made to support low- and middle-income countries improve their local sequencing capacity

The potential risks and impact of the start of the 2015–2016 influenza season in the WHO European Region: a rapid risk assessment

Background: Countries in the World Health Organization (WHO) European Region are reporting more severe influenza activity in the 2015–2016 season compared to previous seasons. Objectives: To conduct a rapid risk assessment to provide interim information on the severity of the current influenza season. Methods: Using the WHO manual for rapid risk assessment of acute public health events and surveillance data available from Flu News Europe, an assessment of the current influenza season from 28 September 2015 (week 40/2015) up to 31 January 2016 (week 04/2016) was made compared with the four previous seasons. Results: The current influenza season started around week 51/2015 with higher influenza activity reported in Eastern Europe compared to Western Europe. There is a strong predominance of influenza A(H1N1)pdm09 compared to previous seasons, but the virus is antigenically similar to the strain included in the seasonal influenza vaccine. Compared to the 2014/2015 season, there was a rapid increase in the number of severe cases in Eastern European countries with the majority of such cases occurring among adults aged < 65 years. Conclusions: The current influenza season is characterized by an early start in Eastern European countries, with indications of a more severe season. Currently circulating influenza A(H1N1)pdm09 viruses are antigenically similar to those included in the seasonal influenza vaccine, and the vaccine is expected to be effective. Authorities should provide information to the public and health providers about the current influenza season, recommendations for the treatment of severe disease and effective public health measures to prevent influenza transmission

Contemporary methods for realization and estimation of efficiency of 3Daudio technology application for sound interface improvement of an aircraft cabin

High information load of crew is one of the main problems of modern piloted aircraft therefore researches on approving data representation form, especially in critical situations are a challenge. The article considers one of opportunities to improve the interface of a modern pilot's cabin i.e. to use a spatial sound (3D - audio technology). The 3D - audio is a technology, which recreates a spatially directed sound in earphones or via loudspeakers. Spatial audio-helps, which together with information on danger will specify also the direction from which it proceeds, can reduce time of response to an event and, therefore, increase situational safety of flight. It is supposed that helps will be provided through pilot's headset therefore technology realization via earphones is discussed.Now the main hypothesis explaining the human ability to recognize the position of a sound source in space, asserts that the human estimates distortion of a sound signal spectrum at interaction with the head and an auricle depending on an arrangement of the sound source. For exact describing the signal spectrum variations there are such concepts as Head Related Impulse Response (HRIR) and Head Related Transfer Function (HRTF). HRIR is measured in humans or dummies. At present the most full-scale public HRIR library is CIPIC HRTF Database of CIPIC Interface Laboratory at UC Davis.To have 3D audio effect, it is necessary to simulate a mono-signal conversion through the linear digital filters with anthropodependent pulse characteristics (HRIR) for the left and right ear, which correspond to the chosen direction. Results should be united in a stereo file and applied for reproduction to the earphones.This scheme was realized in Matlab, and the received software was used for experiments to estimate the quantitative characteristics of technology. For processing and subsequent experiments the following sound signals were chosen: a fragment of the classical music piece "Polovetsky Dancings" from A.P. Borodin's opera "Prince Igor", the horn sounds, the modulated broadband noise (with the fixed position, and "wandering" in the range ±5º in the vertical direction with respect to the fixed position). In the course of experiments the examinee was offered to define in what of possible positions (on an azimuth ±80º, ±40º, 0º, on an eminence ±45º, 0º, and 90º - over the head) there is a virtual source of sound.According to results of experiments, directions with "rough" gradation 90 ° (in a horizontal "at the left–direct-on the right", in a vertical ""up-direct-down") are distinguished with he high probability (on the average 0.94) for all types of signals. Thus the spectral content of signal is of no importance. Results of more accurate recognition with gradation of 40 … 45 ° depend on the type of signal and are different for horizontal and vertical channels. In the horizontal channel the probability of the correct recognition for broadband signals (the modulated noise, classical music) is 0,77 … 0,78, for a sound of horn it is 0,75. In the vertical channel for broadband signals (the modulated noise, classical music) the probability of the correct recognition is 0.48 … 0.50, for a sound of horn it is 0.36. The results allow us to assume that the person recognizes better the position of sound signal sources with rather wide spectrum close to the natural ones (broadband noise, symphonic orchestra).Thus, as a result of the carried-out work the sound processing algorithms have been realized and the software to allow reproducing spatial audio-helps via earphones has been created. In the course of research the methods of a digital filtration as well the statistical methods to analyse the results of experiments have been used. The main result defining a scientific novelty of work is the objective quantitative characteristics of the 3D - audio technology, which are expedient for considering in designing the interfaces for pilots' cabins of modern aircrafts.</p

Airplane Crew Support Implementation Basing on Ellipsoidal Model of the Closed “Pilot-Airplane” Ergatic System

The paper discusses the problem of closed-loop ergatic “pilot - airplane” system monitoring for the purposes of flight safety. The new approach is proposed, based on the confidential ellipsoidal model, which parameters are estimated by flight data processing. The ellipsoidal model of ergatic “pilot - airplane” system enables to detect system emergency operation mode and to identify the source of such emergency mode. The operability of the proposed approach is confirmed by the experimental data processing

Airplane Crew Support Implementation Basing on Ellipsoidal Model of the Closed “Pilot-Airplane” Ergatic System

The paper discusses the problem of closed-loop ergatic “pilot - airplane” system monitoring for the purposes of flight safety. The new approach is proposed, based on the confidential ellipsoidal model, which parameters are estimated by flight data processing. The ellipsoidal model of ergatic “pilot - airplane” system enables to detect system emergency operation mode and to identify the source of such emergency mode. The operability of the proposed approach is confirmed by the experimental data processing