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Typhoon Noru (2022) was a historic storm that caused significant damage to the central region of Vietnam. Typhoon Noru has caused strong winds and torrential rainfall in Da Nang, Quang Nam, and Quang Ngai. Quang Nam Province saw many trees and power lines fall, and many areas were flooded. The Da Nang government has reported the typhoon toppled many trees, blew the rooftops of three houses, damaged the walls of several schools, and caused a power outage at some 3200 substations. It resulted in widespread flooding in coastal areas and downstream from the Vu Gia-Thu Bon River river basin. This study evaluates the impact of Typhoon Noru. The results show that: (1) The numerical simulation was applied to re-analyze the offshore meteorological field with the Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) model as an input for 2D wave propagation and hydraulic models; (2) The study couples the 1D and 2D models in MIKE FLOOD to simulate the flood and inundation caused by Typhoon Noru in the study area. The calibration and validation results of the 1D hydraulic model, the 2D wave propagation model, and the 2D hydrodynamic model were reasonably good, with a Nash coefficient ranging from 0.84 to 0.96 and a percent bias (BIAS) of −0.9% to 7.5%. The results of the simulation showed that the flood and inundation caused by Typhoon Noru resulted in significant damage in two districts: Thang Binh in Quang Nam province and Hoa Vang in Da Nang province. The practical significance of these results is that they provide valuable support for warning systems and troubleshooting efforts related to the impact of typhoons.

The subject and purpose of the work - the COVID-19 pandemic - has so far affected almost all countries of the world and sharply reminded of the need for further research on many aspects of viruses. An attempt to use classical approaches to describe the mechanisms of transmission and spread of this infection and the related methods of carrying out sanitary and preventive measures turned out to be ineffective. Nowadays, the creation of models of new viral infection has acquired particular relevance, allowing one to explain the features of its course observed in practice and to propose a mathematical description of the mechanism of its spread. Methods and methodology of work. The theory of probability and mathematical statistics, numerical modeling tools for solving systems of ordinary differential equations describing the spread of a viral infection are used. Results of work. A lego model for describing the structure of a compound viral infection is proposed, which makes it possible to explain the possibility of recurrent disease and the presence of several waves of it. Estimates of the probability of disease and mortality from the number of fragments of lego infection were obtained. The need to comply with special sanitary and hygienic measures to reduce the likelihood of severe disease and mortality is indicated. Using compartment models, a system of equations has been proposed to describe the dynamics of the spread of a new coronavirus infection COVID-19, which takes into account the presence of the latent period of infection, as well as the possibility of additional infection in a medical institution. Предмет і мета роботи – пандемія COVID-19 наразі торкнулася майже всіх країн світу та гостро нагадала про необхідність подальших досліджень багатьох аспектів вірусів. Спроба використання класичних підходів для опису механізмів передачі та поширення цієї інфекції та пов’язаних з ними методів проведення санітарно-профілактичних заходів виявилася неефективною. У наш час особливої актуальності набуло створення моделей нової вірусної інфекції, що дозволяє пояснити особливості її перебігу, що спостерігаються на практиці, і запропонувати математичний опис механізму її поширення. Методи та методика роботи: в роботі використовуються теорія ймовірності та математична статистика, засоби чисельного моделювання для розв’язування систем звичайних диференціальних рівнянь, що описують поширення вірусної інфекції. Результати роботи: Запропоновано лего модель для опису структури складної вірусної інфекції, яка дає змогу пояснити можливість рецидиву захворювання та наявність кількох його хвиль. Отримано оцінки ймовірності захворюваності та смертності від кількості фрагментів лего зараження. Вказується на необхідність дотримання спеціальних санітарно-гігієнічних заходів для зниження ймовірності тяжкого перебігу захворювання та смертності. За допомогою компартментних моделей запропоновано систему рівнянь для опису динаміки поширення нової коронавірусної інфекції COVID-19, яка враховує наявність латентного періоду інфекції, а також можливість додаткового зараження в лікувальному закладі.

Sofar, studies on labour migration in Vietnam have often focused on domestic migration, international migration, refugee migration, force migration; ignored the cross – border undocumented migration. At the North Central Coast provinces: Ha Tinh, Nghe An, many rural workers always choose Thailand as the destination because of convenience transport and seeking job easily. However, the lack of supplying labour official or contract papers legally, they often faced to risks and uncertainties. This paper aims to provide an analysis of these undocumented migration flows from Vietnam to Thailand by indepth interview and participant observation methods. The main issues in this article include: (1) describes the risks of Vietnamese workers through employment, housing, legal status in Thailand and (2) analysis the coping – risk strategies of Vietnamese workers in Thailand. Inside these, express on the renewal and completion of visa such as a special trick helps them respond to risky types. Finally, the article contributes to the development of new research directions on policies for these undocumented migrant workers.

The methodology for integrated ground-based and satellite monitoring of atmospheric aerosols is discussed. An algorithm for processing data from coordinated lidar and radiometric sensing (LRS) is described. The algorithm was tested by studying aerosol parameter altitude profiles in the vicinity of AERONET stations using data from ground-based solar radiometers and CALIOP satellite lidar. Coordinated measurements with AERONET network radiometers and ground-based multiwavelength lidars at remote sensing stations of the Institute of Physics, NASB (Minsk, Belarus), Institute of Atmospheric Optics, SB, RAS (Tomsk, Russia), and KRSU (Teploklyuchenka, Kyrgyzstan) were used to verify the satellite sensing results.

The paper considers the possibility of using short-wave (SW) band broadcasting stations to detect airborne objects using the Doppler method. It has been shown that detection is possible at Doppler frequencies are spaced from the carrier frequency up to 60 Hz. Air objects moving at speeds up to 2000 km/h have such Doppler shifts in the decameter wavelength band. The relation is given and the detection range of air objects is estimated, the requirements for the degree of suppression of the direct illuminating signal are determined. The spectral characteristics of the signals of HF broadcasting stations have been studied experimentally. Theoretical estimates of the RCS of air objects of various types at different polarizations are given, including airplanes are made using the Stealth technology. It has been experimentally confirmed that their RCS in the resonant region can reach thousands of square meters and exceed the values in the microwave band by 4…5 orders of magnitude. Noise levels in the Doppler band of detection have been determined and the detection ranges of airborne objects have been estimated. It is shown that if the illumination signal is suppressed by 30…40 dB, the detection ranges can exceed 200 km.

The technical skill level of a surgeon has a significant effect on patients’ surgical outcomes. In the current proficiency-based training of technical surgical skills, an accredited medical educator views the procedure to provide feedback, which is time-consuming, labor-intensive, and subjective. This research developed an automated system to facilitate the work of senior surgeons. More specifically, we introduced data surgical gloves with gold nanowires motion sensors embedded to track the motion of the trainees. We also proposed several machine learning algorithms to analyze recorded signals from the data gloves to automatedly and objectively evaluate the surgical skills with high accuracy.

In this study, the WRF (Weather Research and Forecasting) model was used to simulate and investigate diurnal and annual variations of wind speed and wind power density over Southern Vietnam at 2‐km horizontal resolution for two years (2016 and 2017). The model initial and boundary conditions are from the National Centers for Environmental Prediction (NCEP) Final Analyses (FNL). Observation data for two years at 20 m height at Bac Lieu station were used for model bias correction and investigating diurnal and annual variation of wind speeds. The results show that the WRF model overestimates wind speeds. After bias correction, the model reasonably well simulates wind speeds over the research area. Wind speed and wind power density show much higher values at levels of 50–200 m above ground levels than near ground (20 m) level and significantly higher near the coastal regions than inland. Wind speed has significant annual and diurnal cycles. Both annual and diurnal cycles of wind speeds were well simulated by the model. Wind speed is much stronger during daytime than at nighttime. Low-level wind speed reaches the maximum at about 14 LT to 15 LT when the vertical momentum mixing is highly active. Wind speeds over the eastern coastal region of Southern Vietnam are much stronger in winter than in summer due to two main reasons, including (1) stronger large-scale wind speed in winter than in summer and (2) funnel effect creating a local maximum wind speed over the nearshore ocean which then transports high-momentum air inland in winter.

We investigated concentrations of organic carbon (OC), elemental carbon (EC), and a wide range of particle-bound organic compounds in daily sampled PM2.5 at the remote Pha Din (PDI) – Global Atmosphere Watch (GAW) monitoring station in northwestern Vietnam during an intense 3-week sampling campaign from 23 March to 12 April 2015. The site is known to receive trans-regional air masses during large-scale biomass burning (BB) episodes. BB is a globally widespread phenomenon and BB emission characterization is of high scientific and societal relevance. Emissions composition is influenced by multiple factors (e.g., fuel and thereby vegetation type, fuel moisture, fire temperature, available oxygen). Due to regional variations in these parameters, studies in different world regions are needed. OC composition provides valuable information regarding the health- and climate-relevant properties of PM2.5. Yet, OC composition studies from PDI are missing in the scientific literature to date. Therefore, we quantified 51 organic compounds simultaneously by in situ derivatization thermal desorption gas chromatography and time-of-flight mass spectrometry (IDTD-GC-TOFMS). Anhydrosugars, methoxyphenols, n-alkanes, fatty acids, polycyclic aromatic hydrocarbons, oxygenated polycyclic aromatic hydrocarbons, nitrophenols, and OC were used in a hierarchical cluster analysis highlighting distinctive patterns for periods under low, medium, and high BB influence. The highest particle phase concentration of the typical primary organic aerosol (POA) and possible secondary organic aerosol (SOA) constituents, especially nitrophenols, were found on 5 and 6 April. We linked the trace gas mixing ratios of methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), and ozone (O3) to the statistical classification of BB events based on OA composition and found increased CO and O3 levels during medium and high BB influence. Likewise, a backward trajectory analysis indicates different source regions for the identified periods based on the OA clusters, with cleaner air masses arriving from the northeast, i.e., mainland China and the Yellow Sea. The more polluted periods are characterized by trajectories from the southwest, with more continental recirculation of the medium cluster and more westerly advection for the high cluster. These findings highlight that BB activities in northern Southeast Asia significantly enhance the regional organic aerosol loading and also affect the carbonaceous PM2.5 constituents and the trace gases in northwestern Vietnam. The presented analysis adds valuable data on the carbonaceous and chemical composition of PM2.5, in particular of OC, in a region of scarce data availability, and thus offers a reference dataset from Southeast Asian large-scale BB for future studies. Such a reference dataset may be useful for the evaluation of atmospheric transport simulation models, or for comparison with other world regions and BB types, such as Australian bush fires, African savannah fires, or tropical peatland fires.

The measuring complex of the submillimeter range, implemented on the basis of a gas laser, is described. The technique of measuring the characteristics of dielectrics and the results are presented. It is concluded that it is possible to use the proposed method for validating the results of determining the dielectric characteristics of materials.

The possibility of using the emissions of shortwave (HF) broadcasting stations to detect airborne objects using the Doppler method is considered. It is shown that detection is possible at Doppler frequencies are spaced from the carrier frequency up to 60 Hz. In the decameter wavelength range, such objects are possessed by airborne objects moving at speeds up to 2000 kmph. The relation is given and the detection range of airborne objects is estimated, the requirements for the degree of suppression of the direct backlight signal are determined. The spectral characteristics of the signals of broadcast HF stations are experimentally investigated. Theoretical estimates of the RCS of airborne objects of various types at different polarizations, including aircrafts are made using the Stealth technology, are given. The noise levels in the Doppler detection frequency band are determined and the detection ranges of airborne objects are estimated. It is shown that when the backlight signal is suppressed at 30 … 40 dB, they can reach 200 km

The possibility of using the signals of global satellite navigation systems for diagnosing the state of the sea surface and monitoring waves is considered. The behavior of navigation signals during various sea conditions is analyzed. The possibility of monitoring the disturbance by the magnitude of the fluctuation and the level of fading of the trend component of the received GNSS signal is shown.

In this paper, we present the results of an experimental study of the statistical characteristics of interference of HF broadcast stations (spectra, distribution laws, at different frequencies and at different times of the day) and the results of their approximation by fractal and poly-Gaussian dependences

The financial support by the European Union's Horizon 2020 research and innovation program (ACTRIS-2, grant agreement no. 654109) is gratefully acknowledged. The investigation was supported by the Belarusian Republican Foundation for Fundamental, Research Agreement No. F18EA-011, by the Russian Foundation for Basic Research (grant No. 18-55-81001), and also by Vietnam Academy of Science and Technology (project code QTRU05.01/18-20). The Portuguese team acknowledges the support from the Portuguese Science Foundation, in the frame of the European Regional Development Fund -COMPETE 2020, under the projects UID/GEO/04683/2013 (POCI-01-0145-FEDER-007690), The paper presents the preliminary results of the lidar&radiometer measurement campaign (LRMC2017), estimation of statistical relations between aerosol mode concentrations retrieved from CALIOP and ground-based lidar stations and case study of fire smoke events in the Eurasian regions using combined ground-based and space lidar and radiometer observations., European Union's Horizon 2020 research and innovation program (ACTRIS-2) 654109, Belarusian Republican Foundation for Fundamental, Research F18EA-011, Russian Foundation for Basic Research (RFBR) 18-55-81001, Vietnam Academy of Science and Technology QTRU05.01/18-20, Portuguese Science Foundation, in the frame of the European Regional Development Fund -COMPETE 2020 UID/GEO/04683/2013 (POCI-01-0145-FEDER-007690)

Globally consistent measurements of airborne metal concentrations in fine particulate matter (PM2.5) are important for understanding potential health impacts, prioritizing air pollution mitigation strategies, and enabling global chemical transport model development. PM2.5 filter samples (N ~ 800 from 19 locations) collected from a globally distributed surface particulate matter sampling network (SPARTAN) between January 2013 and April 2019 were analyzed for particulate mass and trace metals content. Metal concentrations exhibited pronounced spatial variation, primarily driven by anthropogenic activities. PM2.5 levels of lead, arsenic, chromium, and zinc were significantly enriched at some locations by factors of 100–3000 compared to crustal concentrations. Levels of metals in PM2.5 and PM10 exceeded health guidelines at multiple sites. For example, Dhaka and Kanpur sites exceeded the US National Ambient Air 3-month Quality Standard for lead (150 ng m−3). Kanpur, Hanoi, Beijing and Dhaka sites had annual mean arsenic concentrations that approached or exceeded the World Health Organization’s risk level for arsenic (6.6 ng m−3). The high concentrations of several potentially harmful metals in densely populated cites worldwide motivates expanded measurements and analyses.

This paper is devoted to solving the problem of atmosphere diagnosis using radiation of the global navigation satellites. New methods for diagnosing the meteorological situation, the refractive state of the troposphere and underlying surface based on the behavior of navigation signals are proposed. The model of the mapping function that takes into account the sphericity of the troposphere and allows more accurate describing of the actual values for the tropospheric delay is proposed.

The possibility of using Latin squares for constructing two-dimensional non-equidistant antenna arrays that can be used for development of radio telescopes and systems for remote sensing of atmospheric and lithospheric radiation has been shown. An algorithm for calculating the coordinates of elements of a non-equidistant antenna array using the values of elements of Latin squares is proposed. It is shown that in this case, it is possible to obtain an almost complete coverage of the grid of spatial frequencies in the region of the arrangement of the elements at small filling coefficients of array. Directional patterns are studied and the side lobes levels are estimated for non-equidistant antennas obtained on the basis of Latin squares. The possibility of synthesizing of large antenna arrays on the basis of composite squares using the embedding of generative Latin squares is shown. The characteristics of the obtained arrays are studied. It is shown that using the shifts and mutual rotations of individual layers is involved in the synthesized array; its characteristics can be substantially improved.

In this article, by combining/following previous publications, we summarize the history of nearly 100 years of development of the Vietnam seismological network and its achievements in earthquake monitoring and seismological research to contribute to prevention and mitigation of natural disasters and sustainable development of the country. Earthquake observation in Vietnam has gone through many stages of development, the first seismic station was established in Sapa by the French in 1924. In the years of 70-80s of the 20th Century, the earthquake monitoring network of Vietnam consisted of 7 stations, including five stations distributed in the Northern part (Phu Lien, Sa Pa, Bac Giang, Hoa Binh, Tuyen Quang) and two stations located in the south (Nha Trang and Da Lat). In the period from 1990 to 2005, the national seismological network with 24 digital seismographs and short-period sensors was created and distributed throughout the country. Today, earthquake monitoring in Vietnam has made great progress, the new seismological network with 30 broadband stations with advanced earthquake monitoring technology been established completely in 2017. The international cooperation on earthquake monitoring and seismological research is always promoted and expanded, over the past 60 years, IGP has collaborated with many scientific organizations from different countries such as Russia, France, China, Japan, Poland, The United State of America,... and prestigious international organizations as UNDP, PTWC, CTBTO, IRIS, ADPC, RIMES,.. Through these cooperations, many research projects have been done and Vietnamese seismologists have been trained and educated at different levels that help to improve their knowledge earthquake monitoring and seismological research. Besides operating the national seismological network, some local seismic networks have also been established by Institute of Geophysics for many years to monitor and study induced seismicity in some reservoirs of hydropower dams such as Son La, Hoa Binh, Tri An, Yaly, Song Tranh, Lai Chau, Huoi Quang, Ban Chat,...

In this paper, the characteristics of wind speed at 20 m height at the Bac Lieu atmospheric physic station (Bac Lieu station) in 2016 were evaluated using the Weibull distribution function. The wind speed data set (every minute) from January 7th to December 31st, 2016 was used to calculate the two parameters of Weibull function including Weibull shape factor “k” and Weibull scale factor “c”. The results showed that at the Bac Lieu station in 2016, the values of k and c were 1.69 and 3.91, respectively. Some characteristics of wind speed were also estimated such as wind energy density (Pa/A=57.3 W/m2), wind speed of maximum energy carrier (Vmec=6.2 m/s), the most probable wind speed (Vmp=2.3 m/s), mean wind speed (Vmean­=3.5 m/s) and standard deviation of wind speeds (s = 2.1 m/s).

The results of synchronous detection of the emission of various components of the electromagnetic and acoustic fields obtained under conditions of low industrial interference and a high level of microseismicity are investigated. To compensate electromagnetic radiation of lithospheric origin, a compensation method was used. The signal loop antenna, recording a mixture of signals of lithospheric and atmospheric-thunderstorm origins, was used as a magnetic core of a steel casing of the borehole. The compensating signal was recorded using an antenna, the receiving coil of which was identical to the coil of the signal antenna. The measurements were carried out in the seismically active region of Russia (the Kamchatka peninsula, the Paratun hydrothermal deposit) at the intersection of the sublatitudinal and submeridional fault zones. Methods for analyzing registration data of non-stationary processes are considered using the example of acoustic-electromagnetic emission of the lithosphere, the electromagnetic component of which is a component of the natural electromagnetic field of the Earth. Their characteristics are estimated and a statistical model is proposed that uses nested semi-Markov processes and finite atomic functions. Observations of geophysical electromagnetic fields, in addition to useful information about the emission processes, contain interference, mainly of technogenic origin. They are especially strong in downhole measurements when a well casing is used as the receiving antenna. These interferences significantly impede the allocation of useful information. The possibility of using bleaching filters to increase the contrast of observation of useful signals of lithospheric origin against their background is considered.

Major national emission sources are assessed by characterization of smoke pollution arising due to traditional agriculture, domestic, and cooking activities in the regions of the biggest biomass burning. Measurement campaigns were carried in Son La and Ba Vi regions, Vietnam, during the dry seasons of 2013 and 2015-2016. PM and BC monitoring, aerosol sampling, chemical speciation were conducted to evaluate ambient smoke level, to relate the characteristics of local on-field emissions to regional aerosols, and to identify the dangerous components of smoke composition. The regions Son La and Ba Vi in February-June faced severe levels of air pollution, with critical PM2.5 and PM10 concentrations up to 130 and 167 µg/m3, respectively, significantly exceeding the air quality standards. A wide range of PM mass concentrations was categorized according to the smoke level, supported by the evolution of carbon (OC, EC) fractions as well as ionic species and molecular markers. The level of PM and BC concentrations was seen to be dependent on factors such as weather conditions and precipitation. Non-acid carbonyls, carboxylates, and aliphatic carbon compounds were evolved with increasing smoke intensity, together with carbonates in coarse size fractions, indicating a large impact of smoke emissions and soil lifted up by the intense fires. On-field emissions in both smoldering and flaming phases were assessed in near-source measurements.