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In the last few decades, the Mekong Delta coastlines have suffered serious erosion. Strong waves during the Northeast Monsoon are one of the main reasons for this. Many types of breakwaters with different structural components have been designed and built to mitigate coastline erosion. Vertical seawalls have been widely used, but they create reflection waves, which can generate water particle kinematics in front of the structure and increase the toe scour. In this study, an innovative block of inclined and porous breakwaters was studied by conducting laboratory-scale experiments. The experimental results show that inclined and porous breakwaters can considerably reduce wave energy due to transmission, reflection, and diffraction compared to inclined breakwaters. The porosity on the front and back sides of the structures has also been studied. Letting sediment-laden seawaters penetrate inside the sheltered zones, porous breakwaters promote accretion and facilitate the forestation of mangrove belts.

Mitigating and adapting to the effects of climate change is an ongoing concern for developing countries like Vietnam. Hence, Vietnam ratified the Paris agreement without delay in October 2016. As a part of its climate policy strategy, the government is proposing to increase the taxes either on coal by 50% or petroleum products by 33.33%. This study employs the GTAP-E-Power model with additional improvements to include non-CO2 emissions to examine the impacts of such a policy on the Vietnamese economy. Results show that the trade-offs of the increased tax on petroleum products (Scenario 1) are much higher than the increased tax on coal (Scenario 2). For example, real GDP in Vietnam declines by 2.23% and 1.05% in Scenario 1 and Scenario 2, respectively. In addition, the country’s emissions level reduces by 10.23% in Scenario 2 compared to a reduction of 7.62% in Scenario 1. A higher tax on coal would foster the extension of renewable energy sectors faster than the impacts resulted from increasing tax on petroleum products. The increased demands by the private sector for electricity generated from renewable sources signals a potential for a sustainable development of the renewable electricity generation sectors in Vietnam.

This article employs a global computable general equilibrium economic model (GTAP-E-PowerS) to examine the impact on the world economy if households in every country self-supply power to meet 30–100% of residential demand, with subsequent monetary savings diverted to consuming more food. Results show the power generation sector reduces output levels by 14%–42% across various countries if households 100% self-supply. Coal mining sectors are adversely affected in numerous countries with contractions of 9%–28% ($6,086-$18,935 million) in the United States and 4%–13% ($2,505–$8,143 million) in Australia. Improved outcomes for the world environment are found with reductions of CO2e emission levels of 2.24%–7.38% (or 924–3,042 MtCO2 equivalent). The agriculture and food-processing sectors expand significantly in many countries but also cause major increases in land prices, particularly in land-scarce countries in Middle East, Europe, Japan, and Taiwan. Results also show the security of food and energy supply are improved along with environmental gains from lower emission levels. However, the energy sector is adversely affected and those countries with a heavy reliance on fossil fuel extraction and mining activities experience significant reductions in real GDP.

Both CO2 and non-CO2 emissions are liable in climate change policies in many countries around the world. However, there are still many impact assessment studies in different regions that consider only CO2 emissions. We hypothesise that excluding non-CO2 greenhouse gas emissions, which are also liable in climate change policies, may lead to misleading results and impacts. We employ a global climate change policy model (GTAP-E-PowerS) to examine how the impact of a uniform carbon tax at US$15 applying to the world regions are different when only CO2 emissions are liable compared to the case that non-CO2 emissions are additionally subject to the tax. That is, the impacts of the carbon tax applying to CO2 emissions only (against no carbon tax) will be compared to the impacts of such a tax applying to both CO2 and non-CO2 greenhouse gas emissions (against no carbon tax). Results show the deviations in the impacts between with and without inclusion of non-CO2 emissions are more obvious in developing countries particularly by comparison to developed nations. Iran, for instance, experiences a higher reduction in real GDP of 1.52 percentage points when non-CO2 emissions are overlooked. These impact deviations also rise with increased costs to economies (e.g., more sectors involved or higher tax rates). We find developing countries experience higher contraction rates in their economies than developed nations. Iran, Kazakhstan, South Africa, China, India, Russia, Mexico, and Indonesia all experience 2–5.1% reductions in real GDP relative to business-as-usual (no carbon tax), while such reductions are below 0.8% in Australia, the United States and other developed nations because emission costs compared to economy size are relatively high in developing nations. Major polluting countries like China, the United States, India, and Russia were also found to have low marginal abatement costs compared to other nations due to high emission levels and input substitution possibilities. To provide more accurate and insightful impacts of climate change policies, we recommend future studies include both CO2 and non-CO2 emissions in models.

In this paper, a printed dipole antenna with U-shaped directors will be designed and constructed on a FR4 substrate for 2.4 GHz and 5.8 GHz bands. This printed dipole antenna has three parts: a reflector at 2.4 GHz, a parasitic at 5.8 GHz and U-shaped directors. The impact of these parameters on reflection coefficient and radiation pattern of antenna will be investigated. In addition, the antenna geometry is optimized with Genetic Algorithm. The results obtained from simulation and measurement will indicate the radiation characteristics such as return loss from 10 dB, radiation pattern and gain of 3 dB.

Energy security has been a major concern in developing countries because of rapid economic development and population growth, low power generation capacity, and unwell-developed transmission infrastructure. Vietnam in this context has been under energy security threats for more than a decade and is currently having a new power policy to strongly develop power generation and distribution networks. It is expected that the country's economy is able to develop substantially due to massively additional energy supply once completing the plants and distribution networks but the likely impacts are still undefined. This paper extends an economic electricity-detailed model to examine the potential impacts of such a new power policy in Vietnam. We find that the policy will decrease the prices of both fossil-based and renewable-based electricity significantly by 40%–78% under a 2030 target scenario, benefiting all sectors in the economy to substitute for fossil fuels. Households are particularly benefited as evidenced by 5.64%–19.19% increases in per-capita utility. Overall, the Vietnamese economy is significantly advantaged with real GDP increasing by 5.44%–24.83% over different scenarios, which are much higher than the findings in other countries. More importantly, the policy moves the country to a low-carbon energy structure in the near future.

See-through-wall imaging radar is considered to be a remarkable application of ultra-wideband communication since it facilitates the observation of moving objects through wall or behind the doors. In this topic, an array of Vivaldi antenna for see-through-wall imaging application will be proposed to operate from 1 GHz to 4 GHz frequency band. The genetic optimization of HFSS is implemented to illustrate the radiation characteristics such as gain, axial ratio, return loss, VSWR, bandwidth and radiation patterns. The characteristics of this mentioned structure will be studied and simulated using HFSS software. In addition, the study of Wilkinson power divider for supplying power to antenna elements is also included.

In this paper, an S-band mixer circuit used for both up- and down- conversion mixers is designed. The proposed mixer works in the range power levels from −20dBm to −3 dBm for the RF input of the down-converter, and for the IF input of the up-converter. The Local oscillator (LO) working at 2.87 GHz has the power level of +2dBm. The simulation and measurement exhibits the conversion loss greater than −10dB and good isolation between RF, IF, and LO ports (RF-LO isolation >30 dB, LO-IF isolation>30 dB, RF-IF isolation>25 dB).