118 research outputs found
Time Strategies of Virtual Communities
The Internet has a significant impact on the perception of time and its organization. There is a growing body of literature that recognizes the importance of measuring social time in relation to the virtual communities of social media. The dynamics of communication in virtual communities largely depend on the time strategies that shape the content plan of a particular medium. Based on contemporary theories such as the concept of ‘timeless time’, we analyze the features of the temporal characteristics of the Internet, considering the multiple dimensions of time in virtual communities.
This study aims to identify time strategies depending on their types (e.g., belonging to the certain platform, or target audience). The research is based on posts from 99 politicized virtual communities on the Vk.com and Telegram platforms in 2022. We employ heatmaps and combine them with cluster analysis. As a result, certain patterns of temporal strategies within communities became apparent, depending on the hour, day of the week, and month. We also establish a connection between time strategies and the event context of 2022.
This article may be of interest to sociologists, political scientists, and researchers in cultural and communication studies who are interested in applied aspects of social time research
Георадарные исследования для подготовки взлетно-посадочной полосы на морском льду в районе полевой базы Оазис Бангера, Восточная Антарктида
When one is carrying out logistic operations at Russian Antarctic stations, organization and safe operation of snow-runways play an important role. Nowadays six of the seven existing stations and field bases of the Russian Antarctic expedition (RAE) are provided with air communication, however, the Bunger Oasis field base is still outside the air transportation structure. The aim of the investigations described in this paper was to find a safe site for organizing a snow-runway in the area of the Bunger Oasis field base. Taking into account the location of the infrastructure objects of RAE within the Bunger Oasis, the central part of the epishelf Transcription Gulf, situated 7 km away from the base, was chosen as the most appropriate site. During the summer field season of the 64th RAE (2018/2019), a geophysical survey using the GPR (Ground-penetrating radar) method was carried out within the area to obtain data on the thickness of the bay ice. The GPR survey conducted shows that the sea ice thickness varies from 2.9 to 3.1 m. Moreover, no signs of discontinuities in the ice layer were found. The area investigated was identified as a safe site suitable for the landing of light and medium aircraft. However, due to the specificity of the relief of the oasis adjacent to the Bay, the weathering products of the rocks composing the hills migrated to the surface of the ice layer. The effect of solar radiation caused the thawing in the areas of such particles to increase, and this, in turn, led to the formation of cavities on the surface, the dimensions of which do not meet the requirements for runway coatings. As a result, in the area under study, the boundaries of the sites were determined that are suitable for the organization of runways for medium and small aircraft without preliminary rolling of the landing site.В настоящей работе представлены результаты исследований, выполненных в районе полевой базы Оазис Бангера в ходе полевого сезона 64-й РАЭ (2018/19 г.). Целью работ был поиск безопасной площадки для организации посадочной полосы для самолетов средней и малой авиации. Наиболее подходящим местом для возможного аэродрома был выбран покров залива Транскрипция, располагающегося на удалении 7 км от базы. В рамках исследований были выполнены геофизические инженерные изыскания методом георадиолокации для определения мощности льда залива и выявления нарушения целостности ледяного покрова. По результатам работ был найден безопасный участок для приема мало- и среднегабаритных самолетов на лыжных шасси
Зависимость диэлектрических свойств керамики титаната бария и композита на его основе от температуры спекания
In this paper, we compare the structure and dielectric properties of the samples of barium titanate ceramics that have been sintered at temperatures of 1100, 1150, 1200, 1250 and 1350 °C and dielectric characteristics of the samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%). It is shown that only samples sintered at the temperature of 1250 and 1350 °C have polarization sufficient for the existence of the piezoelectric effect. For the same samples, the pyroelectric coefficient and reversal polarization significantly exceed those for samples sintered at lower temperatures. Analysis of the samples structure confirmed the dependence of the dielectric properties of the barium titanate ceramics on the grain size and, as a consequence, on the sintering temperature. Based on the studies carried out, the optimal temperature (1250 °С) for obtaining composite samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%) was selected. The temperature dependence of the dielectric constant for the composite samples based on barium ferrite — barium titanate with a sintering temperature of 1250 °C is similar to the dependence for the BaTiO3 ceramic samples sintered at 1350 °C. At room temperatures, the permittivity of the composite samples is also significantly higher than that of the barium titanate ceramic samples obtained at the same sintering temperatures. The addition of barium ferrite to the barium titanate not only increased the permittivity of the composite, but also led to a diffusing of the ferroelectric phase transition and a shift in the temperature of the maximum of the dielectric constant by 10 degrees towards high temperatures.Проведено сравнение структуры и диэлектрических свойств образцов керамики титаната бария, спеченных при температурах 1100, 1150, 1200, 1250 и 1350 °С, и диэлектрических характеристик образцов композита титанат бария (80 % (об.)) — феррит бария (20 % (об.)), спеченных при температурах 1150, 1200 и 1250 °С. Показано, что поляризацию, достаточную для проявления пьезоэлектрического эффекта, имеют только образцы титаната бария, спеченные при температурах 1250 и 1350 °С. У этих же образцов величина пирокоэффициента и остаточной поляризации значительно превосходят аналогичные значения для образцов, спеченных при более низких температурах. Анализ структуры образцов подтвердил зависимость диэлектрических свойств керамики титаната бария от размера зерен и, как следствие, от температуры спекания. На основании проведенных исследований выбран оптимальный режим спекания образцов композита титанат бария (80 % (об.)) — феррит бария (20 % (об.)) —1250 °С. Дальнейшее повышение температуры до 1300 °С показало наличие у данного композита эвтектики. При этом температурная зависимость диэлектрической проницаемости для образцов композита на основе феррита бария — титаната бария с температурой спекания 1250 °С аналогичны зависимости для образцов керамики BaTiO3, спеченных при 1350 °С. При комнатных температурах у образцов композита диэлектрическая проницаемость также значительно больше, чем у образцов керамики титаната бария, полученных при тех же температурах спекания. Добавление феррита бария в состав титаната бария не только повысило диэлектрическую проницаемость композита, но и привело к размытию сегнетоэлектрического фазового перехода и смещению температуры максимума диэлектрической проницаемости на 10 градусов в сторону высоких температур.
Дипептидный аналог холецистокинина-4, ослабляет тревожную реакцию у «высокоэмоциональных» мышей BALB/с и при моделировании алкогольной абстиненции у крыс: сравнение с феназепамом
Anxiolytic effects of dipeptide endogenous cholecystokinin tetrapeptide analogue GB-115 at the dose range 0,25-2,0 mg/ kg after oral administration were studied in rodents with high emotionality. In “elevated plus-maze” test GB-115 anxiolytic activity comparable with phenazepam was shown in inbred “anxious” BALB/c mice and “aged” rats with long-term 10% ethanol experience during ethanol withdrawal. GB-115 at the doses 0,5-2,0 mg/kg didn’t induce sedation, in contrast phenazepam significantly suppressed spontaneous locomotor activity in BALB/c mice in Optovarimex. The data obtained show potent anxiolytic properties GB-115 (tablet 0,001) lacking benzodiazepine’s side-effects in animal models with high emotionality.Изучены анксиолитические свойства ГБ-115, дипептидного аналога эндогенного тетрапептида холецистокинина у животных с повышенным уровнем эмоциональности при пероральном введении в диапазоне доз 0,25-2,0 мг/кг. В тесте ПКЛ анксиолитическое действие ГБ-115, сопоставимое с феназепамом, установлено у инбредных мышей BALB/c и у «старых» крыс, потреблявших 10% раствор этанола в течение 33 недель на фоне алкогольной депривации. ГБ-115 в дозах 0,5-2,0 мг/кг не вызывал седативного действия, в то время как феназепам статистически значимо угнетал спонтанную двигательную активность мышей BALB/c в актометре. Полученные результаты демонстрируют наличие у ГБ-115 (таблетка 0,001) выраженных анксиолитических свойств, лишённых побочных эффектов, характерных для производных бензодиазепина, на экспериментальных моделях с повышенным уровнем тревожност
AWAKE, the advanced proton driven plasma wakefield acceleration experiment at CERN
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world׳s first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented
AWAKE: A Proton-Driven Plasma Wakefield Acceleration Experiment at CERN
The AWAKE Collaboration has been formed in order to demonstrate proton-driven plasma wakefield acceleration for the first time. This acceleration technique could lead to future colliders of high energy but of a much reduced length when compared to proposed linear accelerators. The CERN SPS proton beam in the CNGS facility will be injected into a 10 m plasma cell where the long proton bunches will be modulated into significantly shorter micro-bunches. These micro-bunches will then initiate a strong wakefield in the plasma with peak fields above 1 GV/m that will be harnessed to accelerate a bunch of electrons from about 20 MeV to the GeV scale within a few meters. The experimental program is based on detailed numerical simulations of beam and plasma interactions. The main accelerator components, the experimental area and infrastructure required as well as the plasma cell and the diagnostic equipment are discussed in detail. First protons to the experiment are expected at the end of 2016 and this will be followed by an initial three-four years experimental program. The experiment will inform future larger-scale tests of proton-driven plasma wakefield acceleration and applications to high energy colliders
AWAKE: A proton-driven plasma wakefield acceleration experiment at CERN
The AWAKE Collaboration has been formed in order to demonstrate proton-driven plasma wakefield acceleration for the first time. This acceleration technique could lead to future colliders of high energy but of a much reduced length when compared to proposed linear accelerators. The CERN SPS proton beam in the CNGS facility will be injected into a 10 m plasma cell where the long proton bunches will be modulated into significantly shorter micro bunches. These micro-bunches will then initiate a strong wakefield in the plasma with peak fields above 1 GV/m that will be harnessed to accelerate a bunch of electrons from about 20 MeV to the GeV scale within a few meters. The experimental program is based on detailed numerical simulations of beam and plasma interactions. The main accelerator components, the experimental area and infrastructure required as well as the plasma cell and the diagnostic equipment are discussed in detail. First protons to the experiment are expected at the end of 2016 and this will be followed by an initial three-four years experimental program. The experiment will inform future larger-scale tests of proton-driven plasma wakefield acceleration and applications to high energy colliders.info:eu-repo/semantics/publishedVersio
Experimental Observation of Plasma Wakefield Growth Driven by the Seeded Self-Modulation of a Proton Bunch
We measure the effects of transverse wakefields driven by a relativistic proton bunch in plasma with densities of 2.1 x 10(14) and 7.7 x 10(14) electrons/cm(3). We show that these wakefields periodically defocus the proton bunch itself, consistently with the development of the seeded self-modulation process. We show that the defocusing increases both along the bunch and along the plasma by using time resolved and time-integrated measurements of the proton bunch transverse distribution. We evaluate the transverse wakefield amplitudes and show that they exceed their seed value (< 15 MV/m) and reach over 300 MV/m. All these results confirm the development of the seeded self-modulation process, a necessary condition for external injection of low energy and acceleration of electrons to multi-GeV energy levels
Path to AWAKE : evolution of the concept
This paper describes the conceptual steps in reaching the design of the AWAKE experiment currently under construction at CERN. We start with an introduction to plasma wakefield acceleration and the motivation for using proton drivers. We then describe the self-modulation instability - a key to an early realization of the concept. This is then followed by the historical development of the experimental design, where the critical issues that arose and their solutions are described. We conclude with the design of the experiment as it is being realized at CERN and some words on the future outlook. A summary of the AWAKE design and construction status as presented in this conference is given in Gschwendtner et al. [1]
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