Do the internet, economic growth, and environmental quality spur people's happiness during Covid-19 pandemic?

Factors affecting people's happiness have attracted much attention in the context of the COVID-19 pandemic. This paper was conducted to investigate whether internet use, economic growth, and environmental quality improvements can ease psychological darns caused by the COVID-19 pandemic. In the context of Southeast countries, and by applying the Bayesian inference, the findings of this study are summarized: (i) internet use and economic growth positively drive people's happiness; (ii) the effect of environmental quality on happiness is unclear in the context of the COVID-19 pandemic. Based on this evidence, the study suggests practical implications for policymakers in boosting economic growth and enhancing people's happiness

EVALUATION OF BIODEGRADATION RATE CONSTANT (K₁) AND BOD POLLUTION IN THE LAKE SYSTEM OF HANOI

Joint Research on Environmental Science and Technology for the Eart

COMPLETE REPAIR FOR TETRALOGY OF FALLOT IN CHILDREN: SHORT-TERM OUTCOME IN A SINGLE CENTER

Tetralogy of Fallot is a common cyanotic congenital heart disease. Early surgery treatment gives patients a chance to have normal physical and mental health due to preventing complications of cyanosis and even death as a natural history of tetralogy of Fallot. This study aimed to show short-term outcomes (including the time of postoperative hospital stay and 30 days after discharge) of tetralogy of Fallot complete repair at the Department of Pediatric Cardiac Surgery, Cho Ray Hospital. A retrospective study was performed on the data of medical documents of 38 patients, who underwent complete repair for tetralogy of Fallot with full sternotomy and cardiopulmonary bypass from March 2017 to December 2019, following a collection form. The results showed the average age and weight were 33.89±13.02 months and 11.77±2.48 kg. The cardiopulmonary bypass time was 147.74±12.48 mins, the aortic cross-clamp time 104.84±9.73 mins, the mechanical ventilation time 31.14±10.75 hours, the duration of stay in the intensive care unit 58.03±13.56 hours, the postoperative hospital stay time 10.12±1.5 days, and the mortality rate 2.6%. The study concludes that the short-term surgical outcome of complete repair for tetralogy of Fallot in lightweight children is safe and effective with a low mortality rate

NUMERICAL SIMULATION OF AIRFLOW AROUND VEHICLE MODELS

This article carries out the numerical simulation of airflow over three dimensional car models using ANSYS Fluent software. The calculations have been performed by using realizable k-e turbulence model. The external airflow field of the simplified BMV M6 model with or without a wing is simulated. Several aerodynamic characteristics such as pressure distribution, velocity contours, velocity vectors, streamlines, turbulence kinetic energy and turbulence dissipation energy are analyzed in this study. The aerodynamic forces acting on the car model is calculated and compared with other authors

Groundwater recharge in Mekong River Delta: An application of the water-table fluctuation method in the Long Xuyen Quadrangle and the Ca Mau Peninsula

Local groundwater recharge was determined using the Water Table Fluctuation method in the Long Xuyen Quadrangle and the Ca Mau Peninsula to refine existing estimates in a range of aquifer lithologies in light of climate change. The approach takes advantage of long term monthly water level records of Vietnam by Division of Water Resources Planning and Investigation for the South of Vietnam. An analysis of water levels in eight observation wells during four climatically distinct years (2005, 2009, 2013, and 2020) was used in combination with the monthly meteorological data. Groundwater recharge was estimated by the Water Table Fluctuation method to vary from 95.7 to 150.4 mm/year and account for 5.3 to 7.5% of the total rainfall. The estimates fall within the range of values used in regional-scale recharge models and demonstrate the potential of the Water Table Fluctuation method for resolving spatial and temporal variations of groundwater recharge

A moving element method using timoshenko’s beam theory for dynamic analysis of train-track systems

The paper presents a dynamic analysis of train-track systems supported by viscoelastic foundations by combining Timoshenko’s beam theory and moving element method (MEM). In the proposed method, a three-node beam element is utilized to get a high order approximation for the deflection of Timoshenko beam. The reduced integral method is applied in order to avoid the shear-locking phenomenon when computing the shear strain energy of the rail beam. In addition, the behavior of train-track system with respect to time is deduced by using Newmark’s constant acceleration method. Numerical results show that the proposed method is free of shear locking and gives a good agreement with Koh et al.’s method using Euler-Bernoulli beam theory

Monitoring Cirrus Cloud and Tropopause Height over Hanoi Using a Compact Lidar System

Abstract. Cirrus clouds in the upper troposphere and the lower stratosphere have attracted great attention due to their important role and impact on the atmospheric radioactive balance. Because cirrus clouds are located high in the atmosphere, their study requires a high resolution remote sensing technique not only for detection but also for the characterization of their properties. The lidar technique with its inherent high sensitivity and resolution has become an indispensible tool for studying and improving our understanding of cirrus cloud. Using lidar technique we can simultaneously measure the cloud height, thickness and follow its temporal evolution. In this paper we describe the development of a compact and highly sensitive lidar system with the aim to remotely monitor for the first time the cirrus clouds over Hanoi (21001’42’’N, 105051’12’’W). From the lidar data collected during the year 2011. We derive the mean cloud height, location of cloud top, the cloud mean thickness and their temporal evolution. We then compare the location of the cloud top with the position of the tropopause determined the radiosonde data and found good that the distance between cloud top and tropopause remains fairly stable, indicating that generally the top of cirrus clouds is the good tracer of the tropopause. We found that the cirrus clouds are generally located at height between 11.2 to 15 km with average height of 13.4 km. Their thickness is between 0.3 and 3.8 km with average value of 1.7 km. We also compare the properties of cirrus cloud with that observed at other locations around the world based on lidar technique

Heat Dissipation for Microprocessor Using Multiwalled Carbon Nanotubes Based Liquid

Carbon nanotubes (CNTs) are one of the most valuable materials with high thermal conductivity (2000 W/m·K compared with thermal conductivity of Ag 419 W/m·K). This suggested an approach in applying the CNTs in thermal dissipation system for high power electronic devices, such as computer processor and high brightness light emitting diode (HB-LED). In this work, multiwalled carbon nanotubes (MWCNTs) based liquid was made by COOH functionalized MWCNTs dispersed in distilled water with concentration in the range between 0.2 and 1.2 gram/liter. MWCNT based liquid was used in liquid cooling system to enhance thermal dissipation for computer processor. By using distilled water in liquid cooling system, CPU’s temperature decreases by about 10°C compared with using fan cooling system. By using MWCNT liquid with concentration of 1 gram/liter MWCNTs, the CPU’s temperature decreases by 7°C compared with using distilled water in cooling system. Theoretically, we also showed that the presence of MWCNTs reduced thermal resistance and increased the thermal conductivity of liquid cooling system. The results have confirmed the advantages of the MWCNTs for thermal dissipation systems for the μ-processor and other high power electronic devices

Multichannel Photon Counting Lidar Measurements Using USB-based Digital Storage Oscilloscope

We present a simple method of making multichannel photon counting measurements of weak lidar signal from large ranges, using commonly available USB-based digital storage oscilloscopes. The single photon pulses from compact photomultiplier tubes are amplified and stretched so that the pulses are large and broad enough to be sampled efficiently by the USB oscilloscopes. A software interface written in Labview is then used to count the number of photon pulses in each of the prescribed time bins to form the histogram of LIDAR signal. This method presents a flexible alternative to the modular multichannel scalers and facilitate the development of sensitive lidar systems